Viewport Size Code:
Login | Create New Account
picture

  MENU

About | Classical Genetics | Timelines | What's New | What's Hot

About | Classical Genetics | Timelines | What's New | What's Hot

icon

Bibliography Options Menu

icon
QUERY RUN:
HITS:
PAGE OPTIONS:
Hide Abstracts   |   Hide Additional Links
NOTE:
Long bibliographies are displayed in blocks of 100 citations at a time. At the end of each block there is an option to load the next block.

Bibliography on: Biodiversity and Metagenomics

The Electronic Scholarly Publishing Project: Providing world-wide, free access to classic scientific papers and other scholarly materials, since 1993.

More About:  ESP | OUR CONTENT | THIS WEBSITE | WHAT'S NEW | WHAT'S HOT

ESP: PubMed Auto Bibliography 22 May 2024 at 01:30 Created: 

Biodiversity and Metagenomics

If evolution is the only light in which biology makes sense, and if variation is the raw material upon which selection works, then variety is not merely the spice of life, it is the essence of life — the sine qua non without which life could not exist. To understand biology, one must understand its diversity. Historically, studies of biodiversity were directed primarily at the realm of multicellular eukaryotes, since few tools existed to allow the study of non-eukaryotes. Because metagenomics allows the study of intact microbial communities, without requiring individual cultures, it provides a tool for understanding this huge, hitherto invisible pool of biodiversity, whether it occurs in free-living communities or in commensal microbiomes associated with larger organisms.

Created with PubMed® Query: biodiversity metagenomics NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

-->

RevDate: 2024-05-21

Ameer A, Saleem F, Keating C, et al (2024)

Dataset of 130 metagenome-assembled genomes of healthy and diseased broiler chicken caeca from Pakistan.

Data in brief, 54:110487.

This article presents metagenomic-assembled genomes (MAGs) of prokaryotic organisms originating from chicken caeca. The samples originate from broiler chickens, one group was infected with Newcastle Disease Virus (NDV) and one uninfected control group. There were four birds per group. Both groups were raised on commercially available antibiotic free feed under a semi-controlled setup. The binning step of the samples identified 130 MAGs with ≥50 % completion, and ≤10 % contamination. The data presented includes sequences in FASTA format, tables of functional annotation of genes, and data from two different approaches for phylogenetic tree construction using these MAGs. Major geochemical cycles at community level including carbon, sulfur, and nitrogen cycles are also presented.

RevDate: 2024-05-21
CmpDate: 2024-05-18

Min K, Glowacki AJ, Bosma ML, et al (2024)

Quantitative analysis of the effects of essential oil mouthrinses on clinical plaque microbiome: a parallel-group, randomized trial.

BMC oral health, 24(1):578.

BACKGROUND: The rich diversity of microorganisms in the oral cavity plays an important role in the maintenance of oral health and development of detrimental oral health conditions. Beyond commonly used qualitative microbiome metrics, such as relative proportions or diversity, both the species-level identification and quantification of bacteria are key to understanding clinical disease associations. This study reports the first-time application of an absolute quantitative microbiome analysis using spiked DNA standards and shotgun metagenome sequencing to assess the efficacy and safety of product intervention on dental plaque microbiome.

METHODS: In this parallel-group, randomized clinical trial, essential oil mouthrinses, including LISTERINE® Cool Mint Antiseptic (LCM), an alcohol-containing prototype mouthrinse (ACPM), and an alcohol-free prototype mouthrinse (AFPM), were compared against a hydroalcohol control rinse on clinical parameters and the oral microbiome of subjects with moderate gingivitis. To enable a sensitive and clinically meaningful measure of bacterial abundances, species were categorized according to their associations with oral conditions based on published literature and quantified using known amounts of spiked DNA standards.

RESULTS: Multivariate analysis showed that both LCM and ACPM shifted the dysbiotic microbiome composition of subjects with gingivitis to a healthier state after 4 weeks of twice-daily use, resembling the composition of subjects with clinically healthy oral conditions recruited for observational reference comparison at baseline. The essential oil-containing mouthrinses evaluated in this study showed statistically significant reductions in clinical gingivitis and plaque measurements when compared to the hydroalcohol control rinse after 6 weeks of use.

CONCLUSIONS: By establishing a novel quantitative method for microbiome analysis, this study sheds light on the mechanisms of LCM mouthrinse efficacy on oral microbial ecology, demonstrating that repeated usage non-selectively resets a gingivitis-like oral microbiome toward that of a healthy oral cavity.

TRIAL REGISTRATION: The trial was registered on ClinicalTrials.gov on 10/06/2021. The registration number is NCT04921371.

RevDate: 2024-05-18
CmpDate: 2024-05-18

Nebauer DJ, Pearson LA, BA Neilan (2024)

Critical steps in an environmental metaproteomics workflow.

Environmental microbiology, 26(5):e16637.

Environmental metaproteomics is a rapidly advancing field that provides insights into the structure, dynamics, and metabolic activity of microbial communities. As the field is still maturing, it lacks consistent workflows, making it challenging for non-expert researchers to navigate. This review aims to introduce the workflow of environmental metaproteomics. It outlines the standard practices for sample collection, processing, and analysis, and offers strategies to overcome the unique challenges presented by common environmental matrices such as soil, freshwater, marine environments, biofilms, sludge, and symbionts. The review also highlights the bottlenecks in data analysis that are specific to metaproteomics samples and provides suggestions for researchers to obtain high-quality datasets. It includes recent benchmarking studies and descriptions of software packages specifically built for metaproteomics analysis. The article is written without assuming the reader's familiarity with single-organism proteomic workflows, making it accessible to those new to proteomics or mass spectrometry in general. This primer for environmental metaproteomics aims to improve accessibility to this exciting technology and empower researchers to tackle challenging and ambitious research questions. While it is primarily a resource for those new to the field, it should also be useful for established researchers looking to streamline or troubleshoot their metaproteomics experiments.

RevDate: 2024-05-21
CmpDate: 2024-05-18

Laue HE, Bonham KS, Coker MO, et al (2024)

Prospective association of the infant gut microbiome with social behaviors in the ECHO consortium.

Molecular autism, 15(1):21.

BACKGROUND: Identifying modifiable risk factors of autism spectrum disorders (ASDs) may inform interventions to reduce financial burden. The infant/toddler gut microbiome is one such feature that has been associated with social behaviors, but results vary between cohorts. We aimed to identify consistent overall and sex-specific associations between the early-life gut microbiome and autism-related behaviors.

METHODS: Utilizing the Environmental influences on Children Health Outcomes (ECHO) consortium of United States (U.S.) pediatric cohorts, we gathered data on 304 participants with fecal metagenomic sequencing between 6-weeks to 2-years postpartum (481 samples). ASD-related social development was assessed with the Social Responsiveness Scale (SRS-2). Linear regression, PERMANOVA, and Microbiome Multivariable Association with Linear Models (MaAsLin2) were adjusted for sociodemographic factors. Stratified models estimated sex-specific effects.

RESULTS: Genes encoding pathways for synthesis of short-chain fatty acids were associated with higher SRS-2 scores, indicative of ASDs. Fecal concentrations of butyrate were also positively associated with ASD-related SRS-2 scores, some of which may be explained by formula use.

LIMITATIONS: The distribution of age at outcome assessment differed in the cohorts included, potentially limiting comparability between cohorts. Stool sample collection methods also differed between cohorts. Our study population reflects the general U.S. population, and thus includes few participants who met the criteria for being at high risk of developing ASD.

CONCLUSIONS: Our study is among the first multicenter studies in the U.S. to describe prospective microbiome development from infancy in relation to neurodevelopment associated with ASDs. Our work contributes to clarifying which microbial features associate with subsequent diagnosis of neuropsychiatric outcomes. This will allow for future interventional research targeting the microbiome to change neurodevelopmental trajectories.

RevDate: 2024-05-21
CmpDate: 2024-05-21

Han B, He Y, Chen J, et al (2024)

Different microbial functional traits drive bulk and rhizosphere soil phosphorus mobilization in an alpine meadow after nitrogen input.

The Science of the total environment, 931:172904.

Enhanced nitrogen (N) input is expected to influence the soil phosphorus (P) cycling through biotic and abiotic factors. Among these factors, soil microorganisms play a vital role in regulating soil P availability. However, the divergent contribution of functional microorganisms to soil P availability in the rhizosphere and bulk soil under N addition remains unclear. We conducted an N addition experiment with four N input rates (0, 5, 10, and 15 g N m[-2] year[-1]) in an alpine meadow over three years. Metagenomics was employed to investigate the functional microbial traits in the rhizosphere and bulk soil. We showed that N addition had positive effects on microbial functional traits related to P-cycling in the bulk and rhizosphere soil. Specifically, high N addition significantly increased the abundance of most microbial genes in the bulk soil but only enhanced the abundance of five genes in the rhizosphere soil. The soil compartment, rather than the N addition treatment, was the dominant factor explaining the changes in the diversity and network of functional microorganisms. Furthermore, the abundance of functional microbial genes had a profound effect on soil available P, particularly in bulk soil P availability driven by the ppa and ppx genes, as well as rhizosphere soil P availability driven by the ugpE gene. Our results highlight that N addition stimulates the microbial potential for soil P mobilization in alpine meadows. Distinct microbial genes play vital roles in soil P availability in bulk and rhizosphere soil respectively. This indicates the necessity for models to further our knowledge of P mobilization processes from the bulk soil to the rhizosphere soil, allowing for more precise predictions of the effects of N enrichment on soil P cycling.

RevDate: 2024-05-21
CmpDate: 2024-05-21

Zhu W, Zhao H, Ke J, et al (2024)

Deciphering the environmental adaptation and functional trait of core and noncore bacterial communities in impacted coral reef seawater.

The Science of the total environment, 931:172897.

Microorganisms play pivotal roles in different biogeochemical cycles within coral reef waters. Nevertheless, our comprehension of the microbially mediated processes following environmental perturbation is still limited. To gain a deeper insight into the environmental adaptation and nutrient cycling, particularly within core and noncore bacterial communities, it is crucial to understand reef ecosystem functioning. In this study, we delved into the microbial community structure and function of seawater in a coral reef under different degrees of anthropogenic disturbance. To achieve this, we harnessed the power of 16S rRNA gene high-throughput sequencing and metagenomics techniques. The results showed that a continuous temporal succession but little spatial heterogeneity in the bacterial communities of core and noncore taxa and functional profiles involved in nitrogen (N) and phosphorus (P) cycling. Eutrophication state (i.e., nutrient concentration and turbidity) and temperature played pivotal roles in shaping both the microbial community composition and functional traits of coral reef seawater. Within this context, the core subcommunity exhibited a remarkably broader habitat niche breadth, stronger phylogenetic signal and lower environmental sensitivity when compared to the noncore taxa. Null model analysis further revealed that the core subcommunity was governed primarily by stochastic processes, while deterministic processes played a more significant role in shaping the noncore subcommunity. Furthermore, our observations indicated that changes in function related to N cycling were correlated to the variations in noncore taxa, while core taxa played a more substantial role in critical processes such as P cycling. Collectively, these findings facilitated our knowledge about environmental adaptability of core and noncore bacterial taxa and shed light on their respective roles in maintaining diverse nutrient cycling within coral reef ecosystems.

RevDate: 2024-05-21
CmpDate: 2024-05-21

Luo X, Hounmanou YMG, Ndayisenga F, et al (2024)

Spontaneous fermentation mitigates the frequency of genes encoding antimicrobial resistance spreading from the phyllosphere reservoir to the diet.

The Science of the total environment, 931:172712.

The phyllosphere microbiome of vegetable products constitutes an important reservoir for multidrug resistant bacteria and Antibiotic Resistance Genes (ARG). Vegetable products including fermented products such as Paocai therefore may serve as a shuttle for extrinsic microorganisms with ARGs into the gut of consumers. Here we study the effect of fermentation on Paocai ARG dissemination by metagenomic analysis. Microbial abundance and diversity of the Paocai microbiome were diminished during fermentation, which correlated with the reduction of abundance in ARGs. Specifically, as fermentation progressed, Enterobacterales overtook Pseudomonadales as the predominant ARG carriers, and Lactobacillales and Enterobacteriales became the determinants of Paocai resistome variation. Moreover, the dual effect of microbes and metal resistance genes (MRGs) was the major contributor driving Paocai resistome dynamics. We recovered several metagenome-assembled genomes (MAGs) carrying acquired ARGs in the phyllosphere microbiome. ARGs of potential clinical and epidemiological relevance such as tet M and emrB-qacA, were mainly hosted by non-dominant bacterial genera. Overall, our study provides evidence that changes in microbial community composition by fermentation aid in constraining ARG dispersal from raw ingredients to the human microbiome but does not eliminate them.

RevDate: 2024-05-21
CmpDate: 2024-05-21

Reygner J, Delannoy J, Barba-Goudiaby M-T, et al (2024)

Reduction of product composition variability using pooled microbiome ecosystem therapy and consequence in two infectious murine models.

Applied and environmental microbiology, 90(5):e0001624.

Growing evidence demonstrates the key role of the gut microbiota in human health and disease. The recent success of microbiotherapy products to treat recurrent Clostridioides difficile infection has shed light on its potential in conditions associated with gut dysbiosis, such as acute graft-versus-host disease, intestinal bowel diseases, neurodegenerative diseases, or even cancer. However, the difficulty in defining a "good" donor as well as the intrinsic variability of donor-derived products' taxonomic composition limits the translatability and reproducibility of these studies. Thus, the pooling of donors' feces has been proposed to homogenize product composition and achieve higher taxonomic richness and diversity. In this study, we compared the metagenomic profile of pooled products to corresponding single donor-derived products. We demonstrated that pooled products are more homogeneous, diverse, and enriched in beneficial bacteria known to produce anti-inflammatory short chain fatty acids compared to single donor-derived products. We then evaluated pooled products' efficacy compared to corresponding single donor-derived products in Salmonella and C. difficile infectious mouse models. We were able to demonstrate that pooled products decreased pathogenicity by inducing a structural change in the intestinal microbiota composition. Single donor-derived product efficacy was variable, with some products failing to control disease progression. We further performed in vitro growth inhibition assays of two extremely drug-resistant bacteria, Enterococcus faecium vanA and Klebsiella pneumoniae oxa48, supporting the use of pooled microbiotherapies. Altogether, these results demonstrate that the heterogeneity of donor-derived products is corrected by pooled fecal microbiotherapies in several infectious preclinical models.IMPORTANCEGrowing evidence demonstrates the key role of the gut microbiota in human health and disease. Recent Food and Drug Administration approval of fecal microbiotherapy products to treat recurrent Clostridioides difficile infection has shed light on their potential to treat pathological conditions associated with gut dysbiosis. In this study, we combined metagenomic analysis with in vitro and in vivo studies to compare the efficacy of pooled microbiotherapy products to corresponding single donor-derived products. We demonstrate that pooled products are more homogeneous, diverse, and enriched in beneficial bacteria compared to single donor-derived products. We further reveal that pooled products decreased Salmonella and Clostridioides difficile pathogenicity in mice, while single donor-derived product efficacy was variable, with some products failing to control disease progression. Altogether, these findings support the development of pooled microbiotherapies to overcome donor-dependent treatment efficacy.

RevDate: 2024-05-20
CmpDate: 2024-05-18

Min K, Bosma ML, John G, et al (2024)

Quantitative analysis of the effects of brushing, flossing, and mouthrinsing on supragingival and subgingival plaque microbiota: 12-week clinical trial.

BMC oral health, 24(1):575.

BACKGROUND: Translational microbiome research using next-generation DNA sequencing is challenging due to the semi-qualitative nature of relative abundance data. A novel method for quantitative analysis was applied in this 12-week clinical trial to understand the mechanical vs. chemotherapeutic actions of brushing, flossing, and mouthrinsing against the supragingival dental plaque microbiome. Enumeration of viable bacteria using vPCR was also applied on supragingival plaque for validation and on subgingival plaque to evaluate interventional effects below the gingival margin.

METHODS: Subjects with gingivitis were enrolled in a single center, examiner-blind, virtually supervised, parallel group controlled clinical trial. Subjects with gingivitis were randomized into brushing only (B); brushing and flossing (BF); brushing and rinsing with Listerine® Cool Mint® Antiseptic (BA); brushing and rinsing with Listerine® Cool Mint® Zero (BZ); or brushing, flossing, and rinsing with Listerine® Cool Mint® Zero (BFZ). All subjects brushed twice daily for 1 min with a sodium monofluorophosphate toothpaste and a soft-bristled toothbrush. Subjects who flossed used unflavored waxed dental floss once daily. Subjects assigned to mouthrinses rinsed twice daily. Plaque specimens were collected at the baseline visit and after 4 and 12 weeks of intervention. Bacterial cell number quantification was achieved by adding reference amounts of DNA controls to plaque samples prior to DNA extraction, followed by shallow shotgun metagenome sequencing.

RESULTS: 286 subjects completed the trial. The metagenomic data for supragingival plaque showed significant reductions in Shannon-Weaver diversity, species richness, and total and categorical bacterial abundances (commensal, gingivitis, and malodor) after 4 and 12 weeks for the BA, BZ, and BFZ groups compared to the B group, while no significant differences were observed between the B and BF groups. Supragingival plaque vPCR further validated these results, and subgingival plaque vPCR demonstrated significant efficacy for the BFZ intervention only.

CONCLUSIONS: This publication reports on a successful application of a quantitative method of microbiome analysis in a clinical trial demonstrating the sustained and superior efficacy of essential oil mouthrinses at controlling dental plaque compared to mechanical methods. The quantitative microbiological data in this trial also reinforce the safety and mechanism of action of EO mouthrinses against plaque microbial ecology and highlights the importance of elevating EO mouthrinsing as an integral part of an oral hygiene regimen.

TRIAL REGISTRATION: The trial was registered on ClinicalTrials.gov on 31/10/2022. The registration number is NCT05600231.

RevDate: 2024-05-20
CmpDate: 2024-05-18

Li S, Li X, Ye Y, et al (2024)

The rhizosphere microbiome and its influence on the accumulation of metabolites in Bletilla striata (Thunb.) Reichb. f.

BMC plant biology, 24(1):409.

BACKGROUND: Bletilla striata (Thunb.) Reichb. f. (B. striata) is a perennial herbaceous plant in the Orchidaceae family known for its diverse pharmacological activities, such as promoting wound healing, hemostasis, anti-inflammatory effects, antioxidant properties, and immune regulation. Nevertheless, the microbe-plant-metabolite regulation patterns for B. striata remain largely undetermined, especially in the field of rhizosphere microbes. To elucidate the interrelationships between soil physics and chemistry and rhizosphere microbes and metabolites, a comprehensive approach combining metagenome analysis and targeted metabolomics was employed to investigate the rhizosphere soil and tubers from four provinces and eight production areas in China.

RESULTS: Our study reveals that the core rhizosphere microbiome of B. striata is predominantly comprised of Paraburkholderia, Methylibium, Bradyrhizobium, Chitinophaga, and Mycobacterium. These microbial species are recognized as potentially beneficial for plants health. Comprehensive analysis revealed a significant association between the accumulation of metabolites, such as militarine and polysaccharides in B. striata and the composition of rhizosphere microbes at the genus level. Furthermore, we found that the soil environment indirectly influenced the metabolite profile of B. striata by affecting the composition of rhizosphere microbes. Notably, our research identifies soil organic carbon as a primary driving factor influencing metabolite accumulation in B. striata.

CONCLUSION: Our fndings contribute to an enhanced understanding of the comprehensive regulatory mechanism involving microbe-plant-metabolite interactions. This research provides a theoretical basis for the cultivation of high-quality traditional Chinese medicine B. striata.

RevDate: 2024-05-19
CmpDate: 2024-05-19

Wan B, Lei Y, Yuan Z, et al (2024)

Metagenomic dissection of the intestinal microbiome in the giant river prawn Macrobrachium rosenbergii infected with Decapod iridescent virus 1.

Fish & shellfish immunology, 149:109617.

Microbiome in the intestines of aquatic invertebrates plays pivotal roles in maintaining intestinal homeostasis, especially when the host is exposed to pathogen invasion. Decapod iridescent virus 1 (DIV1) is a devastating virus seriously affecting the productivity and success of crustacean aquaculture. In this study, a metagenomic analysis was conducted to investigate the genomic sequences, community structure and functional characteristics of the intestinal microbiome in the giant river prawn Macrobrachiumrosenbergii infected with DIV1. The results showed that DIV1 infection could significantly reduce the diversity and richness of intestinal microbiome. Proteobacteria represented the largest taxon at the phylum level, and at the species level, the abundance of Gonapodya prolifera and Solemya velum gill symbiont increased significantly following DIV1 infection. In the infected prawns, four metabolic pathways related to purine metabolism, pyrimidine metabolism, glycerophospholipid metabolism, and pentose phosphate pathway, and five pathways related to nucleotide excision repair, homologous recombination, mismatch repair, base excision repair, and DNA replication were significantly enriched. Moreover, several immune response related pathways, such as shigellosis, bacterial invasion of epithelial cells, Salmonella infection, and Vibrio cholerae infection were repressed, indicating that secondary infection in M. rosenbergii may be inhibited via the suppression of these immune related pathways. DIV1 infection led to the induction of microbial carbohydrate enzymes such as the glycoside hydrolases (GHs), and reduced the abundance and number of antibiotic-resistant ontologies (AROs). A variety of AROs were identified from the microbiota, and mdtF and lrfA appeared as the dominant genes in the detected AROs. In addition, antibiotic efflux, antibiotic inactivation, and antibiotic target alteration were the main antibiotic resistance mechanisms. Collectively, the data would enable a deeper understanding of the molecular response of intestinal microbiota to DIV1, and offer more insights into its roles in prawn resistance to DIVI infection.

RevDate: 2024-05-19
CmpDate: 2024-05-19

Ye T, He S, Li J, et al (2024)

Metagenomic and transcriptomic analysis revealing the impact of oxytetracycline and ciprofloxacin on gut microbiota and gene expression in the Chinese giant salamander (Andrias davidianus).

Aquatic toxicology (Amsterdam, Netherlands), 271:106925.

Excessive antibiotic use has led to the spread of antibiotic resistance genes (ARGs), impacting gut microbiota and host health. However, the effects of antibiotics on amphibian populations remain unclear. We investigated the impact of oxytetracycline (OTC) and ciprofloxacin (CIP) on Chinese giant salamanders (Andrias davidianus), focusing on gut microbiota, ARGs, and gene expression by performing metagenome and transcriptome sequencing. A. davidianus were given OTC (20 or 40 mg/kg) or CIP (50 or 100 mg/kg) orally for 7 days. The results revealed that oral administration of OTC and CIP led to distinct changes in microbial composition and functional potential, with CIP treatment having a greater impact than OTC. Antibiotic treatment also influenced the abundance of ARGs, with an increase in fluoroquinolone and multi-drug resistance genes observed post-treatment. The construction of metagenome-assembled genomes (MAGs) accurately validated that CIP intervention enriched fish-associated potential pathogens Aeromonas hydrophila carrying an increased number of ARGs. Additionally, mobile genetic elements (MGEs), such as phages and plasmids, were implicated in the dissemination of ARGs. Transcriptomic analysis of the gut revealed significant alterations in gene expression, particularly in immune-related pathways, with differential effects observed between OTC and CIP treatments. Integration of metagenomic and transcriptomic data highlighted potential correlations between gut gene expression and microbial composition, suggesting complex interactions between the host gut and its gut microbiota in response to antibiotic exposure. These findings underscore the importance of understanding the impact of antibiotic intervention on the gut microbiome and host health in amphibians, particularly in the context of antibiotic resistance and immune function.

RevDate: 2024-05-19
CmpDate: 2024-05-19

Lim TW, Huang S, Zhang Y, et al (2024)

A comparison of the prevalence of respiratory pathogens and opportunistic respiratory pathogenic profile of 'clean' and 'unclean' removable dental prostheses.

Journal of dentistry, 145:104968.

OBJECTIVES: To determine and compare the opportunistic respiratory pathogenic index (ORPI) and prevalence of respiratory pathogens between clean and unclean removable prostheses.

METHODS: A cross-sectional study was conducted among 97 removable prosthesis wearers at a teaching dental hospital. Participants' prosthesis hygiene was grouped into clean and unclean. After prosthesis plaque samples were sequenced using the Type IIB Restriction-site Associated DNA Sequencing for Microbiome method, the prevalence was assessed for the presence of respiratory pathogens on each sample. The ORPIs for clean and unclean prostheses were quantified based on the sum of the relative abundance of respiratory pathogenic bacteria in a microbiome using a reference database that contains opportunistic respiratory pathogens and disease-associated information.

RESULTS: A total of 30 opportunistic respiratory pathogens were identified on the removable prostheses. Eighty-one (83.5 %) removable prostheses harboured respiratory pathogenic bacteria. Stenotrophomonas maltophilia (34.0 %), Pseudomonas aeruginosa (27.8 %), and Streptococcus agalactiae (27.8 %) were the top three prevalent respiratory pathogens detected in plaque samples. There was a significantly higher prevalence of respiratory pathogens residing on unclean than clean prostheses (P = 0.046). However, the ORPIs in both groups showed no statistically significant difference (P = 0.516).

CONCLUSIONS: The ORPIs for both clean and unclean prostheses demonstrated a similar abundance of respiratory pathogens. However, the high prevalence of respiratory pathogens residing on unclean prostheses should not be underestimated. Therefore, maintaining good prosthesis hygiene is still important for overall oral and systemic health, even though the direct link between prosthesis cleanliness and reduced abundance of respiratory pathogens has not been established.

CLINICAL SIGNIFICANCE: The association between the prevalence of respiratory pathogens and unclean removable prostheses has been demonstrated and might increase the theoretical risk of respiratory disease development.

RevDate: 2024-05-19
CmpDate: 2024-05-19

Yang S, Sun J, Wang C, et al (2024)

Residue quality drives SOC sequestration by altering microbial taxonomic composition and ecophysiological function in desert ecosystem.

Environmental research, 250:118518.

Plant residues are important sources of soil organic carbon in terrestrial ecosystems. The degradation of plant residue by microbes can influence the soil carbon cycle and sequestration. However, little is known about the microbial composition and function, as well as the accumulation of soil organic carbon (SOC) in response to the inputs of different quality plant residues in the desert environment. The present study evaluated the effects of plant residue addition from Pinus sylvestris var. mongolica (Pi), Artemisia desertorum (Ar) and Amorpha fruticosa (Am) on desert soil microbial community composition and function in a field experiment in the Mu Us Desert. The results showed that the addition of the three plant residues with different C/N ratios induced significant variation in soil microbial communities. The Am treatment (low C/N ratio) improved microbial diversity compared with the Ar and Pi treatments (medium and high C/N ratios). The variations in the taxonomic and functional compositions of the dominant phyla Actinobacteria and Proteobacteria were higher than those of the other phyla among the different treatments. Moreover, the network links between Proteobacteria and other phyla and the CAZyme genes abundances from Proteobacteria increased with increasing residue C/N, whereas those decreased for Actinobacteria. The SOC content of the Am, Ar and Pi treatments increased by 45.73%, 66.54% and 107.99%, respectively, as compared to the original soil. The net SOC accumulation was positively correlated with Proteobacteria abundance and negatively correlated with Actinobacteria abundance. These findings showed that changing the initial quality of plant residue from low C/N to high C/N can result in shifts in taxonomic and functional composition from Actinobacteria to Proteobacteria, which favors SOC accumulation. This study elucidates the ecophysiological roles of Actinobacteria and Proteobacteria in the desert carbon cycle, expands our understanding of the potential microbial-mediated mechanisms by which plant residue inputs affect SOC sequestration in desert soils, and provides valuable guidance for species selection in desert vegetation reconstruction.

RevDate: 2024-05-17
CmpDate: 2024-05-17

Zhao J, Guan G, Li D, et al (2024)

Study on the gut symbiotic microbiota in long- and short-winged brown planthopper, Nilaparvata lugens (Stål).

Scientific reports, 14(1):11306.

The brown planthopper (BPH), Nilaparvata lugens (Stål), is one of the most important rice pests in Asia rice regions. BPH has monophagy, migration, rapid reproduction and strong environmental adaptability, and its control is a major problem in pest management. Adult BPH exhibit wing dimorphism, and the symbiotic microbiota enriched in the gut can provide energy for wing flight muscles as a source of nutrition. In order to study the diversity of symbiotic microbiota in different winged BPHs, this paper takes female BPH as the research object. It was found that the number of symbiotic microbiota of different winged BPHs would change at different development stages. Then, based on the 16S rRNA and ITS sequences, a metagenomic library was constructed, combined with fluorescent quantitative PCR and high-throughput sequencing, the dominant symbiotic microbiota flora in the gut of different winged BPHs was found, and the community structure and composition of symbiotic microbiota in different winged BPHs were further determined. Together, our results preliminarily revealed that symbiotic microbiota in the gut of BPHs have certain effects on wing morphology, and understanding the mechanisms underlying wing morph differentiation will clarify how nutritional factors or environmental cues alter or regulate physiological and metabolic pathways. These findings also establish a theoretical basis for subsequent explorations into BPH-symbiont interplay.

RevDate: 2024-05-16
CmpDate: 2024-05-16

Elbakary M, Hammad SF, Youseif SH, et al (2024)

Revealing the diversity of Jojoba-associated fungi using amplicon metagenome approach and assessing the in vitro biocontrol activity of its cultivable community.

World journal of microbiology & biotechnology, 40(7):205.

Jojoba shrubs are wild plants cultivated in arid and semiarid lands and characterized by tolerance to drought, salinity, and high temperatures. Fungi associated with such plants may be attributed to the tolerance of host plants against biotic stress in addition to the promotion of plant growth. Previous studies showed the importance of jojoba as jojoba oil in the agricultural field; however, no prior study discussed the role of jojoba-associated fungi (JAF) in reflecting plant health and the possibility of using JAF in biocontrol. Here, the culture-independent and culture-dependent approaches were performed to study the diversity of the jojoba-associated fungi. Then, the cultivable fungi were evaluated for in-vitro antagonistic activity and in vitro plant growth promotion assays. The metagenome analysis revealed the existence of four fungal phyla: Ascomycota, Aphelidiomycota, Basidiomycota, and Mortierellomycota. The phylum Ascomycota was the most common and had the highest relative abundance in soil, root, branch, and fruit samples (59.7%, 50.7%, 49.8%, and 52.4%, respectively). Alternaria was the most abundant genus in aboveground tissues: branch (43.7%) and fruit (32.1%), while the genus Discosia had the highest abundance in the underground samples: soil (24%) and root (30.7%). For the culture-dependent method, a total of 14 fungi were isolated, identified, and screened for their chitinolytic and antagonist activity against three phytopathogenic fungi (Fusarium oxysporum, Alternaria alternata and Rhizoctonia solani) as well as their in vitro plant growth promotion (PGP) activity. Based on ITS sequence analysis, the selected potent isolates were identified as Aspergillus stellatusEJ-JFF3, Aspergillus flavus EJ-JFF4, Stilbocrea sp. EJ-JLF1, Fusarium solani EJ-JRF3, and Amesia atrobrunneaEJ-JSF4. The endophyte strain A. flavus EJ-JFF4 exhibited the highest chitinolytic activity (9 Enzyme Index) and antagonistic potential against Fusarium oxysporum, Alternaria alternata, and Rhizoctonia solani phytopathogens with inhibitory percentages of 72, 70, and 80 respectively. Also, A. flavus EJ-JFF4 had significant multiple PGP properties, including siderophore production (69.3%), phosphate solubilization (95.4 µg ml[-1]). The greatest production of Indol-3-Acetic Acid was belonged to A. atrobrunnea EJ-JSF4 (114.5 µg ml[-1]). The analysis of FUNGuild revealed the abundance of symbiotrophs over other trophic modes, and the guild of endophytes was commonly assigned in all samples. For the first time, this study uncovered fungal diversity associated with jojoba plants using a culture-independent approach and in-vitro assessed the roles of cultivable fungal strains in promoting plant growth and biocontrol. The present study indicated the significance of jojoba shrubs as a potential source of diverse fungi with high biocontrol and PGP activities.

RevDate: 2024-05-18
CmpDate: 2024-05-16

Norenhag J, Edfeldt G, Stålberg K, et al (2024)

Compositional and functional differences of the vaginal microbiota of women with and without cervical dysplasia.

Scientific reports, 14(1):11183.

Alterations in the vaginal microbiota, including both species composition and functional pathways, have been associated with HPV infection and progression of dysplasia to cervical cancer. To further explore this, shotgun metagenomic sequencing was used to taxonomically and functionally characterize the vaginal microbiota of women with and without cervical dysplasia. Women with histologically verified dysplasia (n = 177; low grade dysplasia (LSIL) n = 81, high-grade dysplasia (HSIL) n = 94, cancer n = 2) were compared with healthy controls recruited from the cervical screening programme (n = 177). Women with dysplasia had a higher vaginal microbial diversity, and higher abundances of Gardnerella vaginalis, Aerococcus christensenii, Peptoniphilus lacrimalis and Fannyhessea vaginae, while healthy controls had higher relative abundance of Lactobacillus crispatus. Genes involved in e.g. nucleotide biosynthesis and peptidoglycan biosynthesis were more abundant in women with dysplasia. Healthy controls showed higher abundance of genes important for e.g. amino acid biosynthesis, (especially L-lysine) and sugar degradation. These findings suggest that the microbiota may have a role in creating a pro-oncogenic environment in women with dysplasia. Its role and potential interactions with other components in the microenvironment deserve further exploration.

RevDate: 2024-05-17

Singh P, Singh SM, Segawa T, et al (2024)

Bacterial diversity and biopotentials of Hamtah glacier cryoconites, Himalaya.

Frontiers in microbiology, 15:1362678.

Cryoconite is a granular structure present on the glaciers and ice sheets found in polar regions including the Himalayas. It is composed of organic and inorganic matter which absorb solar radiations and reduce ice surface albedo, therefore impacting the melting and retreat of glaciers. Though climate warming has a serious impact on Himalayan glaciers, the biodiversity of sub-glacier ecosystems is poorly understood. Moreover, cryoconite holes are unique habitats for psychrophile biodiversity hotspots in the NW Himalayas, but unfortunately, studies on the microbial diversity of such habitats remain elusive. Therefore, the current study was designed to explore the bacterial diversity of the Hamtah Glacier Himalaya using both culturable and non-culturable approaches. The culturable bacterial count ranged from 2.0 × 10[3] to 8.8 × 10[5] colony-forming units (CFUs)/g at the different locations of the glacier. A total of 88 bacterial isolates were isolated using the culturable approach. Based on the 16S ribosomal RNA gene (16S rRNA), the identified species belong to seven genera, namely, Cryobacterium, Duganella, Janthinobacterium, Pseudomonas, Peribacillus, Psychrobacter, and Sphingomonas. In the non-culturable approach, high-throughput sequencing of 16S rRNA genes (using MiSeq) showed unique bacterial community profiles and represented 440 genera belonging to 20 phyla, namely, Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, Chloroflexi, Acidobacteria, Planctomycetes, Cyanobacteria, Verrucomicrobia, Spirochaetes, Elusimicrobia, Armatimonadetes, Gemmatimonadetes, Deinococcus-Thermus, Nitrospirae, Chlamydiae, Chlorobi, Deferribacteres, Fusobacteria, Lentisphaerae, and others. High relative abundances of Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes were observed in the samples. Phototrophic (Cyanobacteria and Chloroflexi) and nitrifier (Nitrospirae) in bacterial populations indicated sustenance of the micro-ecosystem in the oligotrophic glacier environment. The isolates varied in their phenotypic characteristics, enzyme activities, and antibiotic sensitivity. Furthermore, the fatty acid profiles of bacterial isolates indicate the predominance of branched fatty acids. Iso-, anteiso-, unsaturated and saturated fatty acids together constituted a major proportion of the total fatty acid composition. High cold-adapted enzyme activities such as lipase and cellulase expressed by Cryobacterium arcticum (KY783365) and protease and cellulase activities by Pseudomonas sp. strains (KY783373, KY783377-79, KY783382) provide evidence of the possible applications of these organisms. Additionally, antibiotic tests indicated that most isolates were sensitive to antibiotics. In conclusion, the present study contributed for the first time to bacterial diversity and biopotentials of cryoconites of Hamtah Glacier, Himalayas. Furthermore, the cold-adapted enzymes and polyunsaturated fatty acids (PUFAs) may provide an opportunity for biotechnology in the Himalayas. Inductively coupled plasma mass spectrometry (ICPMS) analyses showed the presence of several elements in cryoconites, providing a clue for the accelerating melting and retreating of the Hamtah glacier.

RevDate: 2024-05-18

Kaijser W, Lorenz AW, Brauer VS, et al (2024)

Differential associations of five riverine organism groups with multiple stressors.

The Science of the total environment, 934:173105 pii:S0048-9697(24)03252-2 [Epub ahead of print].

The decline of river and stream biodiversity results from multiple simultaneous occuring stressors, yet few studies explore responses explore responses across various taxonomic groups at the same locations. In this study, we address this shortcoming by using a coherent data set to study the association of nine commonly occurring stressors (five chemical, one morphological and three hydraulic) with five taxonomic groups (bacteria, fungi, diatoms, macro-invertebrates and fish). According to studies on single taxonomic groups, we hypothesise that gradients of chemical stressors structure community composition of all taxonomic groups, while gradients of hydraulic and morphological stressors are mainly related to larger organisms such as benthic macro-invertebrates and fish. Organisms were sampled over two years at 20 sites in two catchments: a recently restored urban lowland catchment (Boye) and a moderately disturbed rural mountainous catchment (Kinzig). Dissimilarity matrices were computed for each taxonomic group within a catchment. Taxonomic dissimilarities between sites were linked to stressor dissimilarities using multivariable Generalized Linear Mixed Models. Stressor gradients were longer in the Boye, but did in contrast to the Kinzig not cover low stress intensities. Accordingly, responses of the taxonomic groups were stronger in the Kinzig catchment than in the recently restored Boye catchment. The discrepancy between catchments underlines that associations to stressors strongly depend on which part of the stressor gradient is covered in a catchment. All taxonomic groups were related to conductivity. Bacteria, fungi and macro-invertebrates change with dissolved oxygen, and bacteria and fungi with total nitrogen. Morphological and hydraulic stressors had minor correlations with bacteria, fungi and diatoms, while macro-invertebrates were strongly related to fine sediment and discharge, and fish to high flow peaks. The results partly support our hypotheses about the differential associations of the different taxonomic groups with the stressors.

RevDate: 2024-05-18
CmpDate: 2024-05-16

Kuster R, M Staton (2024)

Readsynth: short-read simulation for consideration of composition-biases in reduced metagenome sequencing approaches.

BMC bioinformatics, 25(1):191.

BACKGROUND: The application of reduced metagenomic sequencing approaches holds promise as a middle ground between targeted amplicon sequencing and whole metagenome sequencing approaches but has not been widely adopted as a technique. A major barrier to adoption is the lack of read simulation software built to handle characteristic features of these novel approaches. Reduced metagenomic sequencing (RMS) produces unique patterns of fragmentation per genome that are sensitive to restriction enzyme choice, and the non-uniform size selection of these fragments may introduce novel challenges to taxonomic assignment as well as relative abundance estimates.

RESULTS: Through the development and application of simulation software, readsynth, we compare simulated metagenomic sequencing libraries with existing RMS data to assess the influence of multiple library preparation and sequencing steps on downstream analytical results. Based on read depth per position, readsynth achieved 0.79 Pearson's correlation and 0.94 Spearman's correlation to these benchmarks. Application of a novel estimation approach, fixed length taxonomic ratios, improved quantification accuracy of simulated human gut microbial communities when compared to estimates of mean or median coverage.

CONCLUSIONS: We investigate the possible strengths and weaknesses of applying the RMS technique to profiling microbial communities via simulations with readsynth. The choice of restriction enzymes and size selection steps in library prep are non-trivial decisions that bias downstream profiling and quantification. The simulations investigated in this study illustrate the possible limits of preparing metagenomic libraries with a reduced representation sequencing approach, but also allow for the development of strategies for producing and handling the sequence data produced by this promising application.

RevDate: 2024-05-18
CmpDate: 2024-05-18

Jang CS, Kim H, Kim D, et al (2024)

MicroPredict: predicting species-level taxonomic abundance of whole-shotgun metagenomic data using only 16S amplicon sequencing data.

Genes & genomics, 46(6):701-712.

BACKGROUND: The importance of the human microbiome in the analysis of various diseases is emerging. The two main methods used to profile the human microbiome are 16S rRNA gene sequencing (16S sequencing) and whole-genome shotgun sequencing (WGS). Owing to the full coverage of the genome in sequencing, WGS has multiple advantages over 16S sequencing, including higher taxonomic profiling resolution at the species-level and functional profiling analysis. However, 16S sequencing remains widely used because of its relatively low cost. Although WGS is the standard method for obtaining accurate species-level data, we found that 16S sequencing data contained rich information to predict high-resolution species-level abundances with reasonable accuracy.

OBJECTIVE: In this study, we proposed MicroPredict, a method for accurately predicting WGS-comparable species-level abundance data using 16S taxonomic profile data.

METHODS: We employed a mixed model using two key strategies: (1) modeling both sample- and species-specific information for predicting WGS abundances, and (2) accounting for the possible correlations among different species.

RESULTS: We found that MicroPredict outperformed the other machine learning methods.

CONCLUSION: We expect that our approach will help researchers accurately approximate the species-level abundances of microbiome profiles in datasets for which only cost-effective 16S sequencing has been applied.

RevDate: 2024-05-17
CmpDate: 2024-05-17

Liao Q, Zhao Y, Wang Z, et al (2024)

Kiwifruit resistance to gray mold is enhanced by yeast-induced modulation of the endophytic microbiome.

The Science of the total environment, 932:173109.

The influence of endophytic microbial community on plant growth and disease resistance is of considerable importance. Prior research indicates that pre-treatment of kiwifruit with the biocontrol yeast Debaryomyces hansenii suppresses gray mold disease induced by Botrytis cinerea. However, the specific underlying mechanisms remain unclear. In this study, Metagenomic sequencing was utilized to analyze the composition of the endophytic microbiome of kiwifruit under three distinct conditions: the healthy state, kiwifruit inoculated with B. cinerea, and kiwifruit treated with D. hansenii prior to inoculation with B. cinerea. Results revealed a dominance of Proteobacteria in all treatment groups, accompanied by a notable increase in the relative abundance of Actinobacteria and Firmicutes. Ascomycota emerged as the major dominant group within the fungal community. Treatment with D. hansenii induced significant alterations in microbial community diversity, specifically enhancing the relative abundance of yeast and exerting an inhibitory effect on B. cinerea. The introduction of D. hansenii also enriched genes associated with energy metabolism and signal transduction, positively influencing the overall structure and function of the microbial community. Our findings highlight the potential of D. hansenii to modulate microbial dynamics, inhibit pathogenic organisms, and positively influence functional attributes of the microbial community.

RevDate: 2024-05-17
CmpDate: 2024-05-17

Nguyen SM, Tran HTT, Long J, et al (2024)

Gut microbiome in association with chemotherapy-induced toxicities among patients with breast cancer.

Cancer, 130(11):2014-2030.

BACKGROUND: Little research has focused on the relationship between gut microbiome and chemotherapy-induced toxicity.

METHODS: This prospective study involves 301 patients with breast cancer who had prechemotherapy stool samples collected. Gut microbiome was sequenced by shotgun metagenomics; associations with chemotherapy-induced toxicities during first-line treatment by gut microbial diversity, composition, and metabolic pathways with severe (i.e., grade ≥3) hematological and gastrointestinal toxicities were evaluated via multivariable logistic regression.

RESULTS: High prechemotherapy α-diversity was associated with a significantly reduced risk of both severe hematological toxicity (odds ratio [OR] = 0.94; 95% CI, 0.89-0.99; p = .048) and neutropenia (OR = 0.94; 95% CI, 0.89-0.99; p = .016). A high abundance of phylum Synergistota, class Synergistia, and order Synergistales were significantly associated with a reduced risk of severe neutropenia; conversely, enrichment of phylum Firmicutes C, class Negativicutes, phylum Firmicutes I, and class Bacilli A, order Paenibacillales were significantly associated with an increased risk of severe neutropenia (p range: 0.012-2.32 × 10[-3]; false discovery rate <0.1). Significant positive associations were also observed between severe nausea/vomiting and high Chao1 indexes, β-diversity (p < .05), 20 species belonging to the family Lachnospiraceae, Oscillospiraceae, and Ruminococcaceae (p value range: 6.14 × 10[-3] to 1.33 × 10[-5]; false discovery rate <0.1), and three metabolic pathways involved in reductive tricarboxylic acid cycle I and cycle II, and an incomplete reductive tricarboxylic acid cycle (p < .01). Conversely, a high abundance of species Odoribacter laneus and the pathway related to the L-proline biosynthesis II were inversely associated with severe nausea/vomiting.

CONCLUSIONS: Our study suggests that gut microbiota may be a potential preventive target to reduce chemotherapy-induced toxicity.

RevDate: 2024-05-17
CmpDate: 2024-05-17

Zhang M, Shi Z, Wu C, et al (2024)

Cushing Syndrome Is Associated With Gut Microbial Dysbiosis and Cortisol-Degrading Bacteria.

The Journal of clinical endocrinology and metabolism, 109(6):1474-1484.

CONTEXT: Cushing syndrome (CS) is a severe endocrine disease characterized by excessive secretion of cortisol with multiple metabolic disorders. While gut microbial dysbiosis plays a vital role in metabolic disorders, the role of gut microbiota in CS remains unclear.

OBJECTIVE: The objective of this work is to examine the alteration of gut microbiota in patients with CS.

METHODS: We performed shotgun metagenomic sequencing of fecal samples from 78 patients with CS and 78 healthy controls matched for age and body mass index. Furthermore, we verify the cortisol degradation capacity of Ruminococcus gnavus in vitro and identify the potential metabolite by LC-MC/MS.

RESULTS: We observed significant differences in microbial composition between CS and controls in both sexes, with CS showing reduced Bacteroidetes (Bacteroides vulgatus) and elevated Firmicutes (Erysipelotrichaceae_bacterium_6_1_45) and Proteobacteria (Enterobacter cloacae). Despite distinct causes of hypercortisolism in ACTH-dependent and ACTH-independent CS, we found no significant differences in metabolic profiles or gut microbiota between the 2 subgroups. Furthermore, we identified a group of gut species, including R. gnavus, that were positively correlated with cortisol levels in CS. These bacteria were found to harbor cortisol-degrading desAB genes and were consistently enriched in CS. Moreover, we demonstrated the efficient capacity of R. gnavus to degrade cortisol to 11-oxygenated androgens in vitro.

CONCLUSION: This study provides evidence of gut microbial dysbiosis in patients with CS and identifies a group of CS-enriched bacteria capable of degrading cortisol. These findings highlight the potential role of gut microbiota in regulating host steroid hormone levels, and consequently host health.

RevDate: 2024-05-15
CmpDate: 2024-05-15

Naliukhin AN, Kozlov AV, Eregin AV, et al (2024)

Responses of soil physico-chemical properties, structure of the microbial community and crop yields to different fertilization practices in Russia's conventional farming system.

Brazilian journal of biology = Revista brasleira de biologia, 84:e282493 pii:S1519-69842024000101135.

The use of fertilizers affects not only the soil fertility and crop yield, but also significantly changes the taxonomic structure of the soil microbiocenosis. Here, based on stationary field experiment, we studied the influence of organo-mineral fertilizer (ОМF), modified by bacteria Bacillus subtilis, H-13 in comparison with different fertilizer systems (organic, mineral, organo-mineral) on (i) crop yield, (ii) physical and chemical properties, and (iii) alpha and beta diversity of the microbial community Albic Retisol (Loamic, Aric, Cutanic, Differentic, Ochric). The studies were carried out against the background of liming (рНКCl - 5.9) and without it (рНКCl - 5.1). The use of only one cattle farmyard manure was less effective than its co-application with mineral fertilizers in half doses. A similar effect was obtained when applying ОМF. In addition, the use of OMF contributes to a significant increase in the reserves of soil organic carbon in the soil layer 0-20 cm by 18%-32%. Using high-throughput sequencing of the 16S rRNA variable V4 gene sequence libraries, 10.759 taxa from 456 genera were identified, assigned to 34 fila (31 bacterial and 3 archaeotic. Unilateral application of mineral fertilizers leads to a significant decrease in the alpha diversity of the structure of soil microbial communities (OTE (other things equal) and Shannon index). A clear clustering of the microbiota was found in the variants with and without the introduction of сattle farmyard manure. It is revealed that the taxonomic structure of the microbiocenosis is formed under the influence of two main factors: crop rotation culture and applied fertilizers. The type of cultivated crop determines the dynamics of the microbiota at the level of larger taxa, such as domains, and fertilizers affect the structure of the microbial community at a lower taxonomic level (phyla, orders, bloodlines). On the basis of the Deseq analysis, marker taxa were identified, according to the share participation of which it is possible to determine the type of cultivated crop and fertilizers used in the experiment. Understanding the dynamics of taxa association and other influential factors can lead to the creation of universal systems of metagenomic indication, where tracking the dynamics of microbial communities will allow for a comprehensive assessment of the agroecological state of soils and timely decisions to prevent their degradation.

RevDate: 2024-05-14
CmpDate: 2024-05-14

Qi YL, Chen YT, Xie YG, et al (2024)

Analysis of nearly 3000 archaeal genomes from terrestrial geothermal springs sheds light on interconnected biogeochemical processes.

Nature communications, 15(1):4066.

Terrestrial geothermal springs are physicochemically diverse and host abundant populations of Archaea. However, the diversity, functionality, and geological influences of these Archaea are not well understood. Here we explore the genomic diversity of Archaea in 152 metagenomes from 48 geothermal springs in Tengchong, China, collected from 2016 to 2021. Our dataset is comprised of 2949 archaeal metagenome-assembled genomes spanning 12 phyla and 392 newly identified species, which increases the known species diversity of Archaea by ~48.6%. The structures and potential functions of the archaeal communities are strongly influenced by temperature and pH, with high-temperature acidic and alkaline springs favoring archaeal abundance over Bacteria. Genome-resolved metagenomics and metatranscriptomics provide insights into the potential ecological niches of these Archaea and their potential roles in carbon, sulfur, nitrogen, and hydrogen metabolism. Furthermore, our findings illustrate the interplay of competition and cooperation among Archaea in biogeochemical cycles, possibly arising from overlapping functional niches and metabolic handoffs. Taken together, our study expands the genomic diversity of Archaea inhabiting geothermal springs and provides a foundation for more incisive study of biogeochemical processes mediated by Archaea in geothermal ecosystems.

RevDate: 2024-05-14
CmpDate: 2024-05-14

Warwick-Dugdale J, Tian F, Michelsen ML, et al (2024)

Long-read powered viral metagenomics in the oligotrophic Sargasso Sea.

Nature communications, 15(1):4089.

Dominant microorganisms of the Sargasso Sea are key drivers of the global carbon cycle. However, associated viruses that shape microbial community structure and function are not well characterised. Here, we combined short and long read sequencing to survey Sargasso Sea phage communities in virus- and cellular fractions at viral maximum (80 m) and mesopelagic (200 m) depths. We identified 2,301 Sargasso Sea phage populations from 186 genera. Over half of the phage populations identified here lacked representation in global ocean viral metagenomes, whilst 177 of the 186 identified genera lacked representation in genomic databases of phage isolates. Viral fraction and cell-associated viral communities were decoupled, indicating viral turnover occurred across periods longer than the sampling period of three days. Inclusion of long-read data was critical for capturing the breadth of viral diversity. Phage isolates that infect the dominant bacterial taxa Prochlorococcus and Pelagibacter, usually regarded as cosmopolitan and abundant, were poorly represented.

RevDate: 2024-05-14
CmpDate: 2024-05-14

Yue J, Zhang D, Cao M, et al (2024)

Response of microbial community composition and function to land use in mining soils of Xikuang Mountain in Hunan.

PloS one, 19(5):e0299550 pii:PONE-D-23-38267.

Nine land types in the northern mining area (BKQ) (mining land, smelting land, living area), the old mining area (LKQ) (whole-ore heap, wasteland, grassland), and southern mining area (NKQ) (grassland, shrubs, farmland) of Xikuang Mountain were chosen to explore the composition and functions of soil bacterial communities under different habitats around mining areas. The composition and functions of soil bacterial communities were compared among the sampling sites using 16S rRNA high-throughput sequencing and metagenomic sequencing. α diversity analysis showed the soil bacterial diversity and abundance in the old mining area were significantly higher than those in the northern mining area. β diversity analysis demonstrated that the soil bacterial community composition was highly similar among different vegetation coverages in the southern mining area. Microbial community function analysis showed the annotated KEGG function pathways and eggNOG function composition were consistent between the grassland of the old mining area and the grassland of the southern mining area. This study uncovers the soil bacterial community composition and functions among different habitats in the mining areas of Xikuang Mountain and will underlie soil ecosystem restoration in different habitats under heavy metal pollution around the mining areas there.

RevDate: 2024-05-14
CmpDate: 2024-05-14

Aguilar C, Alwali A, Mair M, et al (2024)

Actinomycetota bioprospecting from ore-forming environments.

Microbial genomics, 10(5):.

Natural products from Actinomycetota have served as inspiration for many clinically relevant therapeutics. Despite early triumphs in natural product discovery, the rate of unearthing new compounds has decreased, necessitating inventive approaches. One promising strategy is to explore environments where survival is challenging. These harsh environments are hypothesized to lead to bacteria developing chemical adaptations (e.g. natural products) to enable their survival. This investigation focuses on ore-forming environments, particularly fluoride mines, which typically have extreme pH, salinity and nutrient scarcity. Herein, we have utilized metagenomics, metabolomics and evolutionary genome mining to dissect the biodiversity and metabolism in these harsh environments. This work has unveiled the promising biosynthetic potential of these bacteria and has demonstrated their ability to produce bioactive secondary metabolites. This research constitutes a pioneering endeavour in bioprospection within fluoride mining regions, providing insights into uncharted microbial ecosystems and their previously unexplored natural products.

RevDate: 2024-05-16
CmpDate: 2024-05-16

Phan J, Calvo DC, Nair D, et al (2024)

Precision synbiotics increase gut microbiome diversity and improve gastrointestinal symptoms in a pilot open-label study for autism spectrum disorder.

mSystems, 9(5):e0050324.

UNLABELLED: The efficacy of prebiotics and probiotics (synbiotics when combined) to improve symptoms associated with autism spectrum disorder (ASD) has shown considerable inter-study variation, likely due to the complex, heterogeneous nature of the disorder and its associated behavioral, developmental, and gastrointestinal symptoms. Here, we present a precision synbiotic supplementation study in 296 children and adults diagnosed with ASD versus 123 age-matched neurotypical controls. One hundred seventy ASD participants completed the study. Baseline and post-synbiotic assessment of ASD and gastrointestinal (GI) symptoms and deep metagenomic sequencing were performed. Within the ASD cohort, there were significant differences in microbes between subpopulations based on the social responsiveness scale (SRS2) survey (Prevotella spp., Bacteroides, Fusicatenibacter, and others) and gluten and dairy-free diets (Bifidobacterium spp., Lactococcus, Streptococcus spp., and others). At the baseline, the ASD cohort maintained a lower taxonomic alpha diversity and significant differences in taxonomic composition, metabolic pathways, and gene families, with a greater proportion of potential pathogens, including Shigella, Klebsiella, and Clostridium, and lower proportions of beneficial microbes, including Faecalibacterium compared to controls. Following the 3-month synbiotic supplementation, the ASD cohort showed increased taxonomic alpha diversity, shifts in taxonomy and metabolic pathway potential, and improvements in some ASD-related symptoms, including a significant reduction in GI discomfort and overall improved language, comprehension, cognition, thinking, and speech. However, the open-label study design may include some placebo effects. In summary, we found that precision synbiotics modulated the gut microbiome and could be used as supplementation to improve gastrointestinal and ASD-related symptoms.

IMPORTANCE: Autism spectrum disorder (ASD) is prevalent in 1 out of 36 children in the United States and contributes to health, financial, and psychological burdens. Attempts to identify a gut microbiome signature of ASD have produced varied results. The limited pre-clinical and clinical population sizes have hampered the success of these trials. To understand the microbiome associated with ASD, we employed whole metagenomic shotgun sequencing to classify microbial composition and genetic functional potential. Despite being one of the most extensive ASD post-synbiotic assessment studies, the results highlight the complexity of performing such a case-control supplementation study in this population and the potential for a future therapeutic approach in ASD.

RevDate: 2024-05-14

Bei Q, Reitz T, Schädler M, et al (2024)

Metabolic potential of Nitrososphaera-associated clades.

The ISME journal pii:7671376 [Epub ahead of print].

Soil ammonia-oxidizing archaea (AOA) play a crucial role in converting ammonia to nitrite, thereby mobilizing reactive nitrogen species into their soluble form, with a significant impact on nitrogen losses from terrestrial soils. Yet, our knowledge regarding their diversity and functions remains limited. In this study, we reconstructed 97 high-quality AOA metagenome-assembled genomes (MAGs) from 180 soil samples collected in Central Germany during 2014-2019 summers. These MAGs were affiliated with the order Nitrososphaerales (NS) and clustered into four family-level clades (NS-α/γ/δ/ε). Among these MAGs, 75 belonged to the most abundant but least understood δ-clade. Within the δ-clade, the amoA genes in three MAGs from neutral soils showed a 99.5% similarity to the fosmid clone 54d9, which has served as representative of the δ-clade for the past two decades since even today no cultivated representatives are available. 72 MAGs constituted a distinct δ sub-clade, and their abundance and expression activity were more than twice that of other MAGs in slightly acidic soils. Unlike the less abundant clades (α, γ, and ε), the δ-MAGs possessed multiple highly expressed intracellular and extracellular carbohydrate-active enzymes responsible for carbohydrate binding (CBM32) and degradation (GH5), along with highly expressed genes involved in ammonia oxidation. Together, these results suggest metabolic versatility of uncultured soil AOA and a potential mixotrophic or chemolithoheterotrophic lifestyle among 54d9-like AOA.

RevDate: 2024-05-14
CmpDate: 2024-05-14

Yang L, Canarini A, Zhang W, et al (2024)

Microbial life-history strategies mediate microbial carbon pump efficacy in response to N management depending on stoichiometry of microbial demand.

Global change biology, 30(5):e17311.

The soil microbial carbon pump (MCP) is increasingly acknowledged as being directly linked to soil organic carbon (SOC) accumulation and stability. Given the close coupling of carbon (C) and nitrogen (N) cycles and the constraints imposed by their stoichiometry on microbial growth, N addition might affect microbial growth strategies with potential consequences for necromass formation and carbon stability. However, this topic remains largely unexplored. Based on two multi-level N fertilizer experiments over 10 years in two soils with contrasting soil fertility located in the North (Cambisol, carbon-poor) and Southwest (Luvisol, carbon-rich), we hypothesized that different resource demands of microorganism elicit a trade-off in microbial growth potential (Y-strategy) and resource-acquisition (A-strategy) in response to N addition, and consequently on necromass formation and soil carbon stability. We combined measurements of necromass metrics (MCP efficacy) and soil carbon stability (chemical composition and mineral associated organic carbon) with potential changes in microbial life history strategies (assessed via soil metagenomes and enzymatic activity analyses). The contribution of microbial necromass to SOC decreased with N addition in the Cambisol, but increased in the Luvisol. Soil microbial life strategies displayed two distinct responses in two soils after N amendment: shift toward A-strategy (Cambisol) or Y-strategy (Luvisol). These divergent responses are owing to the stoichiometric imbalance between microbial demands and resource availability for C and N, which presented very distinct patterns in the two soils. The partial correlation analysis further confirmed that high N addition aggravated stoichiometric carbon demand, shifting the microbial community strategy toward resource-acquisition which reduced carbon stability in Cambisol. In contrast, the microbial Y-strategy had the positive direct effect on MCP efficacy in Luvisol, which greatly enhanced carbon stability. Such findings provide mechanistic insights into the stoichiometric regulation of MCP efficacy, and how this is mediated by site-specific trade-offs in microbial life strategies, which contribute to improving our comprehension of soil microbial C sequestration and potential optimization of agricultural N management.

RevDate: 2024-05-15
CmpDate: 2024-05-14

Cai H, McLimans CJ, Jiang H, et al (2024)

Aerobic anoxygenic phototrophs play important roles in nutrient cycling within cyanobacterial Microcystis bloom microbiomes.

Microbiome, 12(1):88.

BACKGROUND: During the bloom season, the colonial cyanobacterium Microcystis forms complex aggregates which include a diverse microbiome within an exopolymer matrix. Early research postulated a simple mutualism existing with bacteria benefitting from the rich source of fixed carbon and Microcystis receiving recycled nutrients. Researchers have since hypothesized that Microcystis aggregates represent a community of synergistic and interacting species, an interactome, each with unique metabolic capabilities that are critical to the growth, maintenance, and demise of Microcystis blooms. Research has also shown that aggregate-associated bacteria are taxonomically different from free-living bacteria in the surrounding water. Moreover, research has identified little overlap in functional potential between Microcystis and members of its microbiome, further supporting the interactome concept. However, we still lack verification of general interaction and know little about the taxa and metabolic pathways supporting nutrient and metabolite cycling within Microcystis aggregates.

RESULTS: During a 7-month study of bacterial communities comparing free-living and aggregate-associated bacteria in Lake Taihu, China, we found that aerobic anoxygenic phototrophic (AAP) bacteria were significantly more abundant within Microcystis aggregates than in free-living samples, suggesting a possible functional role for AAP bacteria in overall aggregate community function. We then analyzed gene composition in 102 high-quality metagenome-assembled genomes (MAGs) of bloom-microbiome bacteria from 10 lakes spanning four continents, compared with 12 complete Microcystis genomes which revealed that microbiome bacteria and Microcystis possessed complementary biochemical pathways that could serve in C, N, S, and P cycling. Mapping published transcripts from Microcystis blooms onto a comprehensive AAP and non-AAP bacteria MAG database (226 MAGs) indicated that observed high levels of expression of genes involved in nutrient cycling pathways were in AAP bacteria.

CONCLUSIONS: Our results provide strong corroboration of the hypothesized Microcystis interactome and the first evidence that AAP bacteria may play an important role in nutrient cycling within Microcystis aggregate microbiomes. Video Abstract.

RevDate: 2024-05-14
CmpDate: 2024-05-11

Buysse M, Koual R, Binetruy F, et al (2024)

Detection of Anaplasma and Ehrlichia bacteria in humans, wildlife, and ticks in the Amazon rainforest.

Nature communications, 15(1):3988.

Tick-borne bacteria of the genera Ehrlichia and Anaplasma cause several emerging human infectious diseases worldwide. In this study, we conduct an extensive survey for Ehrlichia and Anaplasma infections in the rainforests of the Amazon biome of French Guiana. Through molecular genetics and metagenomics reconstruction, we observe a high indigenous biodiversity of infections circulating among humans, wildlife, and ticks inhabiting these ecosystems. Molecular typing identifies these infections as highly endemic, with a majority of new strains and putative species specific to French Guiana. They are detected in unusual rainforest wild animals, suggesting they have distinctive sylvatic transmission cycles. They also present potential health hazards, as revealed by the detection of Candidatus Anaplasma sparouinense in human red blood cells and that of a new close relative of the human pathogen Ehrlichia ewingii, Candidatus Ehrlichia cajennense, in the tick species that most frequently bite humans in South America. The genome assembly of three new putative species obtained from human, sloth, and tick metagenomes further reveals the presence of major homologs of Ehrlichia and Anaplasma virulence factors. These observations converge to classify health hazards associated with Ehrlichia and Anaplasma infections in the Amazon biome as distinct from those in the Northern Hemisphere.

RevDate: 2024-05-15
CmpDate: 2024-05-11

Mady EA, Osuga H, Toyama H, et al (2024)

Relationship between the components of mare breast milk and foal gut microbiome: shaping gut microbiome development after birth.

The veterinary quarterly, 44(1):1-9.

The gut microbiota (GM) is essential for mammalian health. Although the association between infant GM and breast milk (BM) composition has been well established in humans, such a relationship has not been investigated in horses. Hence, this study was conducted to analyze the GM formation of foals during lactation and determine the presence of low-molecular-weight metabolites in mares' BM and their role in shaping foals' GM. The fecal and BM samples from six pairs of foals and mares were subjected to 16S ribosomal RNA metagenomic and metabolomic analyses, respectively. The composition of foal GM changed during lactation time; hierarchical cluster analysis divided the fetal GM into three groups corresponding to different time points in foal development. The level of most metabolites in milk decreased over time with increasing milk yield, while threonic acid and ascorbic acid increased. Further analyses revealed gut bacteria that correlated with changes in milk metabolites; for instance, there was a positive correlation between Bacteroidaceae in the foal's gut microbiota and serine/glycine in the mother's milk. These findings help improve the rearing environment of lactating horses and establish artificial feeding methods for foals.

RevDate: 2024-05-13
CmpDate: 2024-05-11

Chai X, Chen X, Yan T, et al (2024)

Intestinal Barrier Impairment Induced by Gut Microbiome and Its Metabolites in School-Age Children with Zinc Deficiency.

Nutrients, 16(9):.

Zinc deficiency affects the physical and intellectual development of school-age children, while studies on the effects on intestinal microbes and metabolites in school-age children have not been reported. School-age children were enrolled to conduct anthropometric measurements and serum zinc and serum inflammatory factors detection, and children were divided into a zinc deficiency group (ZD) and control group (CK) based on the results of serum zinc. Stool samples were collected to conduct metagenome, metabolome, and diversity analysis, and species composition analysis, functional annotation, and correlation analysis were conducted to further explore the function and composition of the gut flora and metabolites of children with zinc deficiency. Beta-diversity analysis revealed a significantly different gut microbial community composition between ZD and CK groups. For instance, the relative abundances of Phocaeicola vulgatus, Alistipes putredinis, Bacteroides uniformis, Phocaeicola sp000434735, and Coprococcus eutactus were more enriched in the ZD group, while probiotic bacteria Bifidobacterium kashiwanohense showed the reverse trend. The functional profile of intestinal flora was also under the influence of zinc deficiency, as reflected by higher levels of various glycoside hydrolases in the ZD group. In addition, saccharin, the pro-inflammatory metabolites, and taurocholic acid, the potential factor inducing intestinal leakage, were higher in the ZD group. In conclusion, zinc deficiency may disturb the gut microbiome community and metabolic function profile of school-age children, potentially affecting human health.

RevDate: 2024-05-13
CmpDate: 2024-05-11

Park G, Kim S, Lee W, et al (2024)

Deciphering the Impact of Defecation Frequency on Gut Microbiome Composition and Diversity.

International journal of molecular sciences, 25(9):.

This study explores the impact of defecation frequency on the gut microbiome structure by analyzing fecal samples from individuals categorized by defecation frequency: infrequent (1-3 times/week, n = 4), mid-frequent (4-6 times/week, n = 7), and frequent (daily, n = 9). Utilizing 16S rRNA gene-based sequencing and LC-MS/MS metabolome profiling, significant differences in microbial diversity and community structures among the groups were observed. The infrequent group showed higher microbial diversity, with community structures significantly varying with defecation frequency, a pattern consistent across all sampling time points. The Ruminococcus genus was predominant in the infrequent group, but decreased with more frequent defecation, while the Bacteroides genus was more common in the frequent group, decreasing as defecation frequency lessened. The infrequent group demonstrated enriched biosynthesis genes for aromatic amino acids and branched-chain amino acids (BCAAs), in contrast to the frequent group, which had a higher prevalence of genes for BCAA catabolism. Metabolome analysis revealed higher levels of metabolites derived from aromatic amino acids and BCAA metabolism in the infrequent group, and lower levels of BCAA-derived metabolites in the frequent group, consistent with their predicted metagenomic functions. These findings underscore the importance of considering stool consistency/frequency in understanding the factors influencing the gut microbiome.

RevDate: 2024-05-15
CmpDate: 2024-05-15

An K, Jia Y, Xie B, et al (2024)

Alterations in the gut mycobiome with coronary artery disease severity.

EBioMedicine, 103:105137.

BACKGROUND: Coronary artery disease (CAD) is a prevalent cardiovascular condition, and numerous studies have linked gut bacterial imbalance to CAD. However, the relationship of gut fungi, another essential component of the intestinal microbiota, with CAD remains poorly understood.

METHODS: In this cross-sectional study, we analyzed fecal samples from 132 participants, split into 31 healthy controls and 101 CAD patients, further categorized into stable CAD (38), unstable angina (41), and acute myocardial infarction (22) groups. We conducted internal transcribed spacer 1 (ITS1) and 16S sequencing to examine gut fungal and bacterial communities.

FINDINGS: Based on ITS1 analyses, Ascomycota and Basidiomycota were the dominant fungal phyla in all the groups. The α diversity of gut mycobiome remained unaltered among the control group and CAD subgroups; however, the structure and composition of the mycobiota differed significantly with the progression of CAD. The abundances of 15 taxa gradually changed with the occurrence and progression of the disease and were significantly correlated with major CAD risk factor indicators. The mycobiome changes were closely linked to gut microbiome dysbiosis in patients with CAD. Furthermore, disease classifiers based on gut fungi effectively identified subgroups with different degrees of CAD. Finally, the FUNGuild analysis further categorized these fungi into distinct ecological guilds.

INTERPRETATION: In conclusion, the structure and composition of the gut fungal community differed from healthy controls to various subtypes of CAD, revealing key fungi taxa alterations linked to the onset and progression of CAD. Our study highlights the potential role of gut fungi in CAD and may facilitate the development of novel biomarkers and therapeutic targets for CAD.

FUNDING: This work was supported by the grants from the National Natural Science Foundation of China (No. 82170302, 92168117, 82370432), National clinical key specialty construction project- Cardiovascular Surgery, the Reform and Development Program of Beijing Institute of Respiratory Medicine (No. Ggyfz202417, Ggyfz202308), the Beijing Natural Science Foundation (No. 7222068); and the Clinical Research Incubation Program of Beijing Chaoyang Hospital Affiliated to Capital Medical University (No. CYFH202209).

RevDate: 2024-05-15
CmpDate: 2024-05-15

Mishra S, Zhang X, X Yang (2024)

Plant communication with rhizosphere microbes can be revealed by understanding microbial functional gene composition.

Microbiological research, 284:127726.

Understanding rhizosphere microbial ecology is necessary to reveal the interplay between plants and associated microbial communities. The significance of rhizosphere-microbial interactions in plant growth promotion, mediated by several key processes such as auxin synthesis, enhanced nutrient uptake, stress alleviation, disease resistance, etc., is unquestionable and well reported in numerous literature. Moreover, rhizosphere research has witnessed tremendous progress due to the integration of the metagenomics approach and further shift in our viewpoint from taxonomic to functional diversity over the past decades. The microbial functional genes corresponding to the beneficial functions provide a solid foundation for the successful establishment of positive plant-microbe interactions. The microbial functional gene composition in the rhizosphere can be regulated by several factors, e.g., the nutritional requirements of plants, soil chemistry, soil nutrient status, pathogen attack, abiotic stresses, etc. Knowing the pattern of functional gene composition in the rhizosphere can shed light on the dynamics of rhizosphere microbial ecology and the strength of cooperation between plants and associated microbes. This knowledge is crucial to realizing how microbial functions respond to unprecedented challenges which are obvious in the Anthropocene. Unraveling how microbes-mediated beneficial functions will change under the influence of several challenges, requires knowledge of the pattern and composition of functional genes corresponding to beneficial functions such as biogeochemical functions (nutrient cycle), plant growth promotion, stress mitigation, etc. Here, we focus on the molecular traits of plant growth-promoting functions delivered by a set of microbial functional genes that can be useful to the emerging field of rhizosphere functional ecology.

RevDate: 2024-05-15
CmpDate: 2024-05-15

Garvin ZK, Abades SR, Trefault N, et al (2024)

Prevalence of trace gas-oxidizing soil bacteria increases with radial distance from Polloquere hot spring within a high-elevation Andean cold desert.

The ISME journal, 18(1):.

High-elevation arid regions harbor microbial communities reliant on metabolic niches and flexibility to survive under biologically stressful conditions, including nutrient limitation that necessitates the utilization of atmospheric trace gases as electron donors. Geothermal springs present "oases" of microbial activity, diversity, and abundance by delivering water and substrates, including reduced gases. However, it is unknown whether these springs exhibit a gradient of effects, increasing their impact on trace gas-oxidizers in the surrounding soils. We assessed whether proximity to Polloquere, a high-altitude geothermal spring in an Andean salt flat, alters the diversity and metabolic structure of nearby soil bacterial populations compared to the surrounding cold desert. Recovered DNA and metagenomic analyses indicate that the spring represents an oasis for microbes in this challenging environment, supporting greater biomass with more diverse metabolic functions in proximal soils that declines sharply with radial distance from the spring. Despite the sharp decrease in biomass, potential rates of atmospheric hydrogen (H2) and carbon monoxide (CO) uptake increase away from the spring. Kinetic estimates suggest this activity is due to high-affinity trace gas consumption, likely as a survival strategy for energy/carbon acquisition. These results demonstrate that Polloquere regulates a gradient of diverse microbial communities and metabolisms, culminating in increased activity of trace gas-oxidizers as the influence of the spring yields to that of the regional salt flat environment. This suggests the spring holds local importance within the context of the broader salt flat and potentially represents a model ecosystem for other geothermal systems in high-altitude desert environments.

RevDate: 2024-05-15
CmpDate: 2024-05-15

Zhang S, Chau HT, Tun HM, et al (2024)

Virological response to nucleos(t)ide analogues treatment in chronic hepatitis B patients is associated with Bacteroides-dominant gut microbiome.

EBioMedicine, 103:105101.

BACKGROUND: Gut dysbiosis is present in chronic hepatitis B virus (HBV) infection. In this study, we integrated microbiome and metabolome analysis to investigate the role of gut microbiome in virological response to nucleos(t)ide analogues (NAs) treatment.

METHODS: Chronic HBV patients were prospectively recruited for steatosis and fibrosis assessments via liver elastography, with full-length 16S sequencing performed to identify the compositional gut microbiota differences. Fasting plasma bile acids were quantified by liquid chromatography-tandem mass spectrometry.

FINDINGS: All patients (n = 110) were characterized into three distinct microbial clusters by their dominant genus: c-Bacteroides, c-Blautia, and c-Prevotella. Patients with c-Bacteroides had a higher plasma ursodeoxycholic acids (UDCA) level and an increase in 7-alpha-hydroxysteroid dehydrogenase (secondary bile acid biotransformation) than other clusters. In NAs-treated patients (n = 84), c-Bacteroides was associated with higher odds of plasma HBV-DNA undetectability when compared with non-c-Bacteroides clusters (OR 3.49, 95% CI 1.43-8.96, p = 0.01). c-Blautia was positively associated with advanced fibrosis (OR 2.74, 95% CI 1.09-7.31, p = 0.04). No such associations were found in treatment-naïve patients. Increased Escherichia coli relative abundance (0.21% vs. 0.03%, p = 0.035) was found in on-treatment patients (median treatment duration 98.1 months) with advanced fibrosis despite HBV DNA undetectability. An enrichment in l-tryptophan biosynthesis was observed in patients with advanced fibrosis, which exhibited a positive correlation with Escherichia coli.

INTERPRETATION: Collectively, unique bacterial signatures, including c-Bacteroides and c-Blautia, were associated with virological undetectability and fibrosis evolution during NAs therapy in chronic HBV, setting up intriguing possibilities in optimizing HBV treatment.

FUNDING: This study was supported by the Guangdong Natural Science Fund (2019A1515012003).

RevDate: 2024-05-13
CmpDate: 2024-05-11

Rekadwad BN, Shouche YS, K Jangid (2024)

A culture-independent approach, supervised machine learning, and the characterization of the microbial community composition of coastal areas across the Bay of Bengal and the Arabian Sea.

BMC microbiology, 24(1):162.

BACKGROUND: Coastal areas are subject to various anthropogenic and natural influences. In this study, we investigated and compared the characteristics of two coastal regions, Andhra Pradesh (AP) and Goa (GA), focusing on pollution, anthropogenic activities, and recreational impacts. We explored three main factors influencing the differences between these coastlines: The Bay of Bengal's shallower depth and lower salinity; upwelling phenomena due to the thermocline in the Arabian Sea; and high tides that can cause strong currents that transport pollutants and debris.

RESULTS: The microbial diversity in GA was significantly higher than that in AP, which might be attributed to differences in temperature, soil type, and vegetation cover. 16S rRNA amplicon sequencing and bioinformatics analysis indicated the presence of diverse microbial phyla, including candidate phyla radiation (CPR). Statistical analysis, random forest regression, and supervised machine learning models classification confirm the diversity of the microbiome accurately. Furthermore, we have identified 450 cultures of heterotrophic, biotechnologically important bacteria. Some strains were identified as novel taxa based on 16S rRNA gene sequencing, showing promising potential for further study.

CONCLUSION: Thus, our study provides valuable insights into the microbial diversity and pollution levels of coastal areas in AP and GA. These findings contribute to a better understanding of the impact of anthropogenic activities and climate variations on biology of coastal ecosystems and biodiversity.

RevDate: 2024-05-13
CmpDate: 2024-05-13

Díaz L, Castellá G, Bragulat MR, et al (2024)

Mycobiome of the external ear canal of healthy cows.

Medical mycology, 62(5):.

Malassezia yeasts belong to the normal skin microbiota of a wide range of warm-blooded animals. However, their significance in cattle is still poorly understood. In the present study, the mycobiota of the external ear canal of 20 healthy dairy Holstein cows was assessed by cytology, culture, PCR, and next-generation sequencing. The presence of Malassezia was detected in 15 cows by cytology and PCR. The metagenomic analysis revealed that Ascomycota was the predominant phylum but M. pachydermatis the main species. The Malassezia phylotype 131 was detected in low abundance. Nor M. nana nor M. equina were detected in the samples.

RevDate: 2024-05-13
CmpDate: 2024-05-13

Sankar J, Thakral V, Bharadwaj K, et al (2024)

The Microbiome and Metabolome of the Gut of Children with Sepsis and Septic Shock.

Journal of intensive care medicine, 39(6):514-524.

BACKGROUND: There is limited understanding of alteration of gut microbiota and metabolome in children with sepsis/septic shock.

METHODS: In this prospective observational study carried out in a pediatric intensive care unit of a tertiary care center from 2020 to 2022, patients aged <17 years with sepsis/septic shock and healthy children (HC) were enrolled. We characterized the gut bacterial compositions by metagenome sequencing and metabolomes by untargeted gas chromatography-mass spectrometry. The primary outcome was to compare the gut microbiota and metabolome of children with sepsis/septic shock with that of HC. The Firmicutes/Bacteroidetes (F/B) ratio was compared between children with sepsis/septic shock and HC. Key secondary outcomes were to evaluate association of factors associated with a low F/B ratio in children with sepsis/septic shock.

RESULTS: A total of 40 children (63% boys) (15 children with sepsis and septic shock and 10 healthy children) with a median (IQR) age of 5.5 (1.5, 10) years were enrolled. In the fecal microbiota, the α-diversity index including Shannon and Simpson indices of the sepsis/septic shock groups was significantly lower than that of the HC. The samples lacked beneficial Bifidobacterium spp. and were dominated by Bacteroides, Enterobacteriaceae, and Enterococcaceae. There was reduction in short-chain fatty acids (SCFAs) in patients with sepsis/septic shock as compared to healthy children. A lower F/B ratio (≤1.57) of the gut microbiota discriminated well between children with sepsis/septic shock and HC. Factors associated with lower F/B ratio were male gender, clinical GI dysfunction, elevated inflammatory markers, and higher organ failure scores.

CONCLUSION: There were significant alterations in the gut microbiota and metabolome in children with sepsis/septic shock as compared to healthy children. Larger study is needed to confirm these exploratory findings and develop potential therapeutic targets that will improve outcomes in children with sepsis/septic shock.

RevDate: 2024-05-12
CmpDate: 2024-05-12

Wang YC, Fu HM, Shen Y, et al (2024)

Biosynthetic potential of uncultured anammox community bacteria revealed through multi-omics analysis.

Bioresource technology, 401:130740.

Microbial secondary metabolites (SMs) and their derivatives have been widely used in medicine, agriculture, and energy. Growing needs for renewable energy and the challenges posed by antibiotic resistance, cancer, and pesticides emphasize the crucial hunt for new SMs. Anaerobic ammonium-oxidation (anammox) systems harbor many uncultured or underexplored bacteria, representing potential resources for discovering novel SMs. Leveraging HiFi long-read metagenomic sequencing, 1,040 biosynthetic gene clusters (BGCs) were unearthed from the anammox microbiome with 58% being complete and showcasing rich diversity. Most of them showed distant relations to known BGCs, implying novelty. Members of the underexplored lineages (Chloroflexota and Planctomycetota) and Proteobacteria contained lots of BGCs, showcasing substantial biosynthetic potential. Metaproteomic results indicated that Planctomycetota members harbored the most active BGCs, particularly those involved in producing potential biofuel-ladderane. Overall, these findings underscore that anammox microbiomes could serve as valuable resources for mining novel BGCs and discovering new SMs for practical application.

RevDate: 2024-05-12
CmpDate: 2024-05-12

Clagnan E, Petrini S, Pioli S, et al (2024)

Conventional activated sludge vs. photo-sequencing batch reactor for enhanced nitrogen removal in municipal wastewater: Microalgal-bacterial consortium and pathogenic load insights.

Bioresource technology, 401:130735.

Municipal wastewater treatment plants are mostly based on traditional activated sludge (AS) processes. These systems are characterised by major drawbacks: high energy consumption, large amount of excess sludge and high greenhouse gases emissions. Treatment through microalgal-bacterial consortia (MBC) is an alternative and promising solution thanks to lower energy consumption and emissions, biomass production and water sanitation. Here, microbial difference between a traditional anaerobic sludge (AS) and a consortium-based system (photo-sequencing batch reactor (PSBR)) with the same wastewater inlet were characterised through shotgun metagenomics. Stable nitrification was achieved in the PSBR ensuring ammonium removal > 95 % and significant total nitrogen removal thanks to larger flocs enhancing denitrification. The new system showed enhanced pathogen removal, a higher abundance of photosynthetic and denitrifying microorganisms with a reduced emissions potential identifying this novel PSBR as an effective alternative to AS.

RevDate: 2024-05-10
CmpDate: 2024-05-10

Li X, Brejnrod A, Trivedi U, et al (2024)

Co-localization of antibiotic resistance genes is widespread in the infant gut microbiome and associates with an immature gut microbial composition.

Microbiome, 12(1):87.

BACKGROUND: In environmental bacteria, the selective advantage of antibiotic resistance genes (ARGs) can be increased through co-localization with genes such as other ARGs, biocide resistance genes, metal resistance genes, and virulence genes (VGs). The gut microbiome of infants has been shown to contain numerous ARGs, however, co-localization related to ARGs is unknown during early life despite frequent exposures to biocides and metals from an early age.

RESULTS: We conducted a comprehensive analysis of genetic co-localization of resistance genes in a cohort of 662 Danish children and examined the association between such co-localization and environmental factors as well as gut microbial maturation. Our study showed that co-localization of ARGs with other resistance and virulence genes is common in the early gut microbiome and is associated with gut bacteria that are indicative of low maturity. Statistical models showed that co-localization occurred mainly in the phylum Proteobacteria independent of high ARG content and contig length. We evaluated the stochasticity of co-localization occurrence using enrichment scores. The most common forms of co-localization involved tetracycline and fluoroquinolone resistance genes, and, on plasmids, co-localization predominantly occurred in the form of class 1 integrons. Antibiotic use caused a short-term increase in mobile ARGs, while non-mobile ARGs showed no significant change. Finally, we found that a high abundance of VGs was associated with low gut microbial maturity and that VGs showed even higher potential for mobility than ARGs.

CONCLUSIONS: We found that the phenomenon of co-localization between ARGs and other resistance and VGs was prevalent in the gut at the beginning of life. It reveals the diversity that sustains antibiotic resistance and therefore indirectly emphasizes the need to apply caution in the use of antimicrobial agents in clinical practice, animal husbandry, and daily life to mitigate the escalation of resistance. Video Abstract.

RevDate: 2024-05-10
CmpDate: 2024-05-10

Tshisekedi KA, De Maayer P, A Botes (2024)

Metagenomic sequencing and reconstruction of 82 microbial genomes from barley seed communities.

Scientific data, 11(1):484.

Barley (Hordeum vulgare) is essential to global food systems and the brewing industry. Its physiological traits and microbial communities determine malt quality. Although microbes influence barley from seed health to fermentation, there is a gap in metagenomic insights during seed storage. Crucially, elucidating the changes in microbial composition associated with barley seeds is imperative for understanding how these fluctuations can impact seed health and ultimately, influence both agricultural yield and quality of barley-derived products. Whole metagenomes were sequenced from eight barley seed samples obtained at different storage time points from harvest to nine months. After binning, 82 metagenome-assembled genomes (MAGs) belonging to 26 distinct bacterial genera were assembled, with a substantial proportion of potential novel species. Most of our MAG dataset (61%) showed over 90% genome completeness. This pioneering barley seed microbial genome retrieval provides insights into species diversity and structure, laying the groundwork for understanding barley seed microbiome interactions at the genome level.

RevDate: 2024-05-10
CmpDate: 2024-05-10

Sequino G, Cobo-Diaz JF, Valentino V, et al (2024)

Microbiome mapping in beef processing reveals safety-relevant variations in microbial diversity and genomic features.

Food research international (Ottawa, Ont.), 186:114318.

The microbiome of surfaces along the beef processing chain represents a critical nexus where microbial ecosystems play a pivotal role in meat quality and safety of end products. This study offers a comprehensive analysis of the microbiome along beef processing using whole metagenomics with a particular focus on antimicrobial resistance and virulence-associated genes distribution. Our findings highlighted that microbial communities change dynamically in the different steps along beef processing chain, influenced by the specific conditions of each micro-environment. Brochothrix thermosphacta, Carnobacterium maltaromaticum, Pseudomonas fragi, Psychrobacter cryohalolentis and Psychrobacter immobilis were identified as the key species that characterize beef processing environments. Carcass samples and slaughterhouse surfaces exhibited a high abundance of antibiotic resistance genes (ARGs), mainly belonging to aminoglycosides, β-lactams, amphenicols, sulfonamides and tetracyclines antibiotic classes, also localized on mobile elements, suggesting the possibility to be transmitted to human pathogens. We also evaluated how the initial microbial contamination of raw beef changes in response to storage conditions, showing different species prevailing according to the type of packaging employed. We identified several genes leading to the production of spoilage-associated compounds, and highlighted the different genomic potential selected by the storage conditions. Our results suggested that surfaces in beef processing environments represent a hotspot for beef contamination and evidenced that mapping the resident microbiome in these environments may help in reducing meat microbial contamination, increasing shelf-life, and finally contributing to food waste restraint.

RevDate: 2024-05-11
CmpDate: 2024-05-10

Yan M, Z Yu (2024)

Viruses contribute to microbial diversification in the rumen ecosystem and are associated with certain animal production traits.

Microbiome, 12(1):82.

BACKGROUND: The rumen microbiome enables ruminants to digest otherwise indigestible feedstuffs, thereby facilitating the production of high-quality protein, albeit with suboptimal efficiency and producing methane. Despite extensive research delineating associations between the rumen microbiome and ruminant production traits, the functional roles of the pervasive and diverse rumen virome remain to be determined.

RESULTS: Leveraging a recent comprehensive rumen virome database, this study analyzes virus-microbe linkages, at both species and strain levels, across 551 rumen metagenomes, elucidating patterns of microbial and viral diversity, co-occurrence, and virus-microbe interactions. Additionally, this study assesses the potential role of rumen viruses in microbial diversification by analyzing prophages found in rumen metagenome-assembled genomes. Employing CRISPR-Cas spacer-based matching and virus-microbe co-occurrence network analysis, this study suggests that the viruses in the rumen may regulate microbes at strain and community levels through both antagonistic and mutualistic interactions. Moreover, this study establishes that the rumen virome demonstrates responsiveness to dietary shifts and associations with key animal production traits, including feed efficiency, lactation performance, weight gain, and methane emissions.

CONCLUSIONS: These findings provide a substantive framework for further investigations to unravel the functional roles of the virome in the rumen in shaping the microbiome and influencing overall animal production performance. Video Abstract.

RevDate: 2024-05-10

Bute TF, Wyness A, Wasserman RJ, et al (2024)

Microbial community and extracellular polymeric substance dynamics in arid-zone temporary pan ecosystems.

The Science of the total environment, 932:173059 pii:S0048-9697(24)03206-6 [Epub ahead of print].

Microbial extracellular polymeric substances (EPS) are an important component in sediment ecology. However, most research is highly skewed towards the northern hemisphere and in more permanent systems. This paper investigates EPS (i.e., carbohydrates and proteins) dynamics in arid Austral zone temporary pans sediments. Colorimetric methods and sequence-based metagenomics techniques were employed in a series of small temporary pan ecosystems characterised by alternating wet and dry hydroperiods. Microbial community patterns of distribution were evaluated between seasons (hot-wet and cool-dry) and across depths (and inferred inundation period) based on estimated elevation. Carbohydrates generally occurred in relatively higher proportions than proteins; the carbohydrate:protein ratio was 2.8:1 and 1.6:1 for the dry and wet season respectively, suggesting that EPS found in these systems was largely diatom produced. The wet- hydroperiods (Carbohydrate mean 102 μg g[-1]; Protein mean 65 μg g[-1]) supported more EPS production as compared to the dry- hydroperiods (Carbohydrate mean 73 μg g[-1]; Protein mean 26 μg g[-1]). A total of 15,042 Unique Amplicon Sequence Variants (ASVs) were allocated to 51 bacterial phyla and 1127 genera. The most abundant genera had commonality in high temperature tolerance, with Firmicutes, Actinobacteria and Proteobacteria in high abundances. Microbial communities were more distinct between seasons compared to within seasons which further suggested that the observed metagenome functions could be seasonally driven. This study's findings implied that there were high levels of denitrification by mostly nitric oxide reductase and nitrite reductase enzymes. EPS production was high in the hot-wet season as compared to relatively lower rates of nitrification in the cool-dry season by ammonia monooxygenases. Both EPS quantities and metagenome functions were highly associated with availability of water, with high rates being mainly associated with wet- hydroperiods compared to dry- hydroperiods. These data suggest that extended dry periods threaten microbially mediated processes in temporary wetlands, with implications to loss of biodiversity by desiccation.

RevDate: 2024-05-08

Wienhausen G, Moraru C, Bruns S, et al (2024)

Ligand cross-feeding resolves bacterial vitamin B12 auxotrophies.

Nature [Epub ahead of print].

Cobalamin (vitamin B12, herein referred to as B12) is an essential cofactor for most marine prokaryotes and eukaryotes[1,2]. Synthesized by a limited number of prokaryotes, its scarcity affects microbial interactions and community dynamics[2-4]. Here we show that two bacterial B12 auxotrophs can salvage different B12 building blocks and cooperate to synthesize B12. A Colwellia sp. synthesizes and releases the activated lower ligand α-ribazole, which is used by another B12 auxotroph, a Roseovarius sp., to produce the corrin ring and synthesize B12. Release of B12 by Roseovarius sp. happens only in co-culture with Colwellia sp. and only coincidently with the induction of a prophage encoded in Roseovarius sp. Subsequent growth of Colwellia sp. in these conditions may be due to the provision of B12 by lysed cells of Roseovarius sp. Further evidence is required to support a causative role for prophage induction in the release of B12. These complex microbial interactions of ligand cross-feeding and joint B12 biosynthesis seem to be widespread in marine pelagic ecosystems. In the western and northern tropical Atlantic Ocean, bacteria predicted to be capable of salvaging cobinamide and synthesizing only the activated lower ligand outnumber B12 producers. These findings add new players to our understanding of B12 supply to auxotrophic microorganisms in the ocean and possibly in other ecosystems.

RevDate: 2024-05-11
CmpDate: 2024-05-08

Hirpara KR, Hinsu AT, RK Kothari (2024)

Metagenomic evaluation of peanut rhizosphere microbiome from the farms of Saurashtra regions of Gujarat, India.

Scientific reports, 14(1):10525.

The narrow zone of soil around the plant roots with maximum microbial activity termed as rhizosphere. Rhizospheric bacteria promote the plant growth directly or indirectly by providing the nutrients and producing antimicrobial compounds. In this study, the rhizospheric microbiota of peanut plants was characterized from different farms using an Illumina-based partial 16S rRNA gene sequencing to evaluate microbial diversity and identify the core microbiome through culture-independent (CI) approach. Further, all rhizospheric bacteria that could grow on various nutrient media were identified, and the diversity of those microbes through culture-dependent method (CD) was then directly compared with their CI counterparts. The microbial population profiles showed a significant correlation with organic carbon and concentration of phosphate, manganese, and potassium in the rhizospheric soil. Genera like Sphingomicrobium, Actinoplanes, Aureimonas _A, Chryseobacterium, members from Sphingomonadaceae, Burkholderiaceae, Pseudomonadaceae, Enterobacteriaceae family, and Bacilli class were found in the core microbiome of peanut plants. As expected, the current study demonstrated more bacterial diversity in the CI method. However, a higher number of sequence variants were exclusively present in the CD approach compared to the number of sequence variants shared between both approaches. These CD-exclusive variants belonged to organisms that are more typically found in soil. Overall, this study portrayed the changes in the rhizospheric microbiota of peanuts in different rhizospheric soil and environmental conditions and gave an idea about core microbiome of peanut plant and comparative bacterial diversity identified through both approaches.

RevDate: 2024-05-11
CmpDate: 2024-05-08

Zhang Y, Chen H, Lian C, et al (2024)

Insights into phage-bacteria interaction in cold seep Gigantidas platifrons through metagenomics and transcriptome analyses.

Scientific reports, 14(1):10540.

Viruses are crucial for regulating deep-sea microbial communities and biogeochemical cycles. However, their roles are still less characterized in deep-sea holobionts. Bathymodioline mussels are endemic species inhabiting cold seeps and harboring endosymbionts in gill epithelial cells for nutrition. This study unveiled a diverse array of viruses in the gill tissues of Gigantidas platifrons mussels and analyzed the viral metagenome and transcriptome from the gill tissues of Gigantidas platifrons mussels collected from a cold seep in the South Sea. The mussel gills contained various viruses including Baculoviridae, Rountreeviridae, Myoviridae and Siphovirdae, but the active viromes were Myoviridae, Siphoviridae, and Podoviridae belonging to the order Caudovirales. The overall viral community structure showed significant variation among environments with different methane concentrations. Transcriptome analysis indicated high expression of viral structural genes, integrase, and restriction endonuclease genes in a high methane concentration environment, suggesting frequent virus infection and replication. Furthermore, two viruses (GP-phage-contig14 and GP-phage-contig72) interacted with Gigantidas platifrons methanotrophic gill symbionts (bathymodiolin mussels host intracellular methanotrophic Gammaproteobacteria in their gills), showing high expression levels, and have huge different expression in different methane concentrations. Additionally, single-stranded DNA viruses may play a potential auxiliary role in the virus-host interaction using indirect bioinformatics methods. Moreover, the Cro and DNA methylase genes had phylogenetic similarity between the virus and Gigantidas platifrons methanotrophic gill symbionts. This study also explored a variety of viruses in the gill tissues of Gigantidas platifrons and revealed that bacteria interacted with the viruses during the symbiosis with Gigantidas platifrons. This study provides fundamental insights into the interplay of microorganisms within Gigantidas platifrons mussels in deep sea.

RevDate: 2024-05-11
CmpDate: 2024-05-11

Guruge KS, Goswami P, Kanda K, et al (2024)

Plastiome: Plastisphere-enriched mobile resistome in aquatic environments.

Journal of hazardous materials, 471:134353.

Aquatic microplastics (MPs) act as reservoirs for microbial communities, fostering the formation of a mobile resistome encompassing diverse antibiotic (ARGs) and biocide/metal resistance genes (BMRGs), and mobile genetic elements (MGEs). This collective genetic repertoire, referred to as the "plastiome," can potentially perpetuate environmental antimicrobial resistance (AMR). Our study examining two Japanese rivers near Tokyo revealed that waterborne MPs are primarily composed of polyethylene and polypropylene fibers and sheets of diverse origin. Clinically important genera like Exiguobacterium and Eubacterium were notably enriched on MPs. Metagenomic analysis uncovered a 3.46-fold higher enrichment of ARGs on MPs than those in water, with multidrug resistance genes (MDRGs) and BMRGs prevailing, particularly within MPs. Specific ARG and BMRG subtypes linked to resistance to vancomycin, beta-lactams, biocides, arsenic, and mercury showed selective enrichment on MPs. Network analysis revealed intense associations between host genera with ARGs, BMRGs, and MGEs on MPs, emphasizing their role in coselection. In contrast, river water exhibited weaker associations. This study underscores the complex interactions shaping the mobile plastiome in aquatic environments and emphasizes the global imperative for research to comprehend and effectively control AMR within the One Health framework.

RevDate: 2024-05-10
CmpDate: 2024-05-10

Kean IRL, Clark JA, Zhang Z, et al (2024)

Short-duration selective decontamination of the digestive tract infection control does not contribute to increased antimicrobial resistance burden in a pilot cluster randomised trial (the ARCTIC Study).

Gut, 73(6):910-921 pii:gutjnl-2023-330851.

OBJECTIVE: Selective decontamination of the digestive tract (SDD) is a well-studied but hotly contested medical intervention of enhanced infection control. Here, we aim to characterise the changes to the microbiome and antimicrobial resistance (AMR) gene profiles in critically ill children treated with SDD-enhanced infection control compared with conventional infection control.

DESIGN: We conducted shotgun metagenomic microbiome and resistome analysis on serial oropharyngeal and faecal samples collected from critically ill, mechanically ventilated patients in a pilot multicentre cluster randomised trial of SDD. The microbiome and AMR profiles were compared for longitudinal and intergroup changes. Of consented patients, faecal microbiome baseline samples were obtained in 89 critically ill children. Additionally, samples collected during and after critical illness were collected in 17 children treated with SDD-enhanced infection control and 19 children who received standard care.

RESULTS: SDD affected the alpha and beta diversity of critically ill children to a greater degree than standard care. At cessation of treatment, the microbiome of SDD patients was dominated by Actinomycetota, specifically Bifidobacterium, at the end of mechanical ventilation. Altered gut microbiota was evident in a subset of SDD-treated children who returned late longitudinal samples compared with children receiving standard care. Clinically relevant AMR gene burden was unaffected by the administration of SDD-enhanced infection control compared with standard care. SDD did not affect the composition of the oral microbiome compared with standard treatment.

CONCLUSION: Short interventions of SDD caused a shift in the microbiome but not of the AMR gene pool in critically ill children at the end mechanical ventilation, compared with standard antimicrobial therapy.

RevDate: 2024-05-10
CmpDate: 2024-05-08

Hong Y, Li H, Chen L, et al (2024)

Short-term exposure to antibiotics begets long-term disturbance in gut microbial metabolism and molecular ecological networks.

Microbiome, 12(1):80.

BACKGROUND: Antibiotic exposure can occur in medical settings and from environmental sources. Long-term effects of brief antibiotic exposure in early life are largely unknown.

RESULTS: Post a short-term treatment by ceftriaxone to C57BL/6 mice in early life, a 14-month observation was performed using 16S rRNA gene-sequencing technique, metabolomics analysis, and metagenomics analysis on the effects of ceftriaxone exposure. Firstly, the results showed that antibiotic pre-treatment significantly disturbed gut microbial α and β diversities (P < 0.05). Both Chao1 indices and Shannon indices manifested recovery trends over time, but they didn't entirely recover to the baseline of control throughout the experiment. Secondly, antibiotic pre-treatment reduced the complexity of gut molecular ecological networks (MENs). Various network parameters were affected and manifested recovery trends over time with different degrees, such as nodes (P < 0.001, R[2] = 0.6563), links (P < 0.01, R[2] = 0.4543), number of modules (P = 0.0672, R[2] = 0.2523), relative modularity (P = 0.6714, R[2] = 0.0155), number of keystones (P = 0.1003, R[2] = 0.2090), robustness_random (P = 0.79, R[2] = 0.0063), and vulnerability (P = 0.0528, R[2] = 0.28). The network parameters didn't entirely recover. Antibiotic exposure obviously reduced the number of key species in gut MENs. Interestingly, new keystones appeared during the recovery process of network complexity. Changes in network stability might be caused by variations in network complexity, which supports the ecological theory that complexity begets stability. Besides, the metabolism profiles of the antibiotic group and control were significantly different. Correlation analysis showed that antibiotic-induced differences in gut microbial metabolism were related to MEN changes. Antibiotic exposure also caused long-term effects on gut microbial functional networks in mice.

CONCLUSIONS: These results suggest that short-term antibiotic exposure in early life will cause long-term negative impacts on gut microbial diversity, MENs, and microbial metabolism. Therefore, great concern should be raised about children's brief exposure to antibiotics if the results observed in mice are applicable to humans. Video Abstract.

RevDate: 2024-05-09
CmpDate: 2024-05-08

Morandi SC, Herzog EL, Munk M, et al (2024)

The gut microbiome and HLA-B27-associated anterior uveitis: a case-control study.

Journal of neuroinflammation, 21(1):120.

BACKGROUND: The human gut microbiome (GM) is involved in inflammation and immune response regulation. Dysbiosis, an imbalance in this ecosystem, facilitates pathogenic invasion, disrupts immune equilibrium, and potentially triggers diseases including various human leucocyte antigen (HLA)-B27-associated autoinflammatory and autoimmune diseases such as inflammatory bowel disease (IBD) and spondyloarthropathy (SpA). This study assesses compositional and functional alterations of the GM in patients with HLA-B27-associated non-infectious anterior uveitis (AU) compared to healthy controls.

METHODS: The gut metagenomes of 20 patients with HLA-B27-associated non-infectious AU, 21 age- and sex-matched HLA-B27-negative controls, and 6 HLA-B27-positive healthy controls without a history of AU were sequenced using the Illumina NovaSeq 6000 platform for whole metagenome shotgun sequencing. To identify taxonomic and functional features with significantly different relative abundances between groups and to identify associations with clinical metadata, the multivariate association by linear models (MaAsLin) R package was applied.

RESULTS: Significantly higher levels of the Eubacterium ramulus species were found in HLA-B27-negative controls (p = 0.0085, Mann-Whitney U-test). No significant differences in microbial composition were observed at all other taxonomic levels. Functionally, the lipid IVA biosynthesis pathway was upregulated in patients (p < 0.0001, Mann-Whitney U-test). A subgroup analysis comparing patients with an active non-infectious AU to their age- and sex-matched HLA-B27-negative controls, showed an increase of the species Phocaeicola vulgatus in active AU (p = 0.0530, Mann-Whitney U-test). An additional analysis comparing AU patients to age- and sex-matched HLA-B27-positive controls, showed an increase of the species Bacteroides caccae in controls (p = 0.0022, Mann-Whitney U-test).

CONCLUSION: In our cohort, non-infectious AU development is associated with compositional and functional alterations of the GM. Further research is needed to assess the causality of these associations, offering potentially novel therapeutic strategies.

RevDate: 2024-05-09
CmpDate: 2024-05-09

Fu Q, Ma X, Li S, et al (2024)

New insights into the interactions between the gut microbiota and the inflammatory response to ulcerative colitis in a mouse model of dextran sodium sulfate and possible mechanisms of action for treatment with PE&AFWE.

Animal models and experimental medicine, 7(2):83-97.

BACKGROUND: Inflammatory bowel disease (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), is a heterogeneous state of chronic intestinal inflammation. Intestinal innate immunity, including innate immune cells, defends against pathogens and excessive entry of gut microbiota, while preserving immune tolerance to resident intestinal microbiota, and may be characterized by its capacity to produce a rapid and nonspecific reaction. The association between microbiota dysbiosis and the pathogenesis of IBD is complex and dynamic. When the intestinal ecosystem is in dysbiosis, the reduced abundance and diversity of intestinal gut microbiota make the host more vulnerable to the attack of exogenous and endogenous pathogenic gut microbiota. The aim of our study was to comprehensively assess the relationship between microbial populations within UC, the signaling pathways of pathogenic gut microbe therein and the inflammatory response, as well as to understand the effects of using PE&AFWE (poppy extract [Papaver nudicaule L.] and Artemisia frigida Willd. extract) on UC modulation.

METHODS: A UC mouse model was established by inducing SPF-grade C57BL/6 mice using dextrose sodium sulfate (DSS). Based on metagenomic sequencing to characterize the gut microbiome, the relationship between gut microbiota dysbiosis and gut microbiota was further studied using random forest and Bayesian network analysis methods, as well as histopathological analysis.

RESULTS: (1) We found that the 5 gut microbiota with the highest relative abundance of inflammatory bowel disease UC model gut microbiota were consistent with the top 5 ranked natural bacteria. There were three types of abundance changes in the model groups: increases (Chlamydiae/Proteobacteria and Deferribacteres), decreases (Firmicutes), and no significant changes (Bacteroidetes). The UC model group was significantly different from the control group, with 1308 differentially expressed species with abundance changes greater than or equal to 2-fold. (2) The proportion of the fecal flora in the UC group decreased by 37.5% in the Firmicutes and increased by 14.29% in the proportion of Proteobacteria compared to the control group before treatment. (3) The significantly enriched and increased signaling pathways screened were the 'arachidonic acid metabolic pathway' and the 'phagosomal pathway', which both showed a decreasing trend after drug administration. (4) Based on the causal relationship between different OTUs and the UC model/PE&AFWE administration, screening for directly relevant OTU networks, the UC group was found to directly affect OTU69, followed by a cascade of effects on OTU12, OTU121, OTU93, and OTU7, which may be the pathway of action that initiated the pathological changes in normal mice. (5) We identified a causal relationship between common differentially expressed OTUs and PE&AFWE and UC in the pre- and post-PE&AFWE-treated groups. Thereby, we learned that PE&AFWE can directly affect OTU90, after which it inhibits UC, inhibiting the activity of arachidonic acid metabolic pathway by affecting OTU118, which in turn inhibits the colonization of gut microbiota by OTU93 and OTU7. (6) Histopathological observation and scoring (HS) of the colon showed that there was a significant difference between the model group and the control group (p < 0.001), and that there was a significant recovery in both the sulfasalazine (SASP)and the PE&AFWE groups after the administration of the drug (p < 0.0001).

CONCLUSION: We demonstrated causal effects and inflammatory metabolic pathways in gut microbiota dysbiosis and IBD, with five opportunistic pathogens directly contributing to IBD. PE&AFWE reduced the abundance of proteobacteria in the gut microbiota, and histopathology showed significant improvement.

RevDate: 2024-05-09
CmpDate: 2024-05-09

Su Q, Lau RI, Liu Q, et al (2024)

The gut microbiome associates with phenotypic manifestations of post-acute COVID-19 syndrome.

Cell host & microbe, 32(5):651-660.e4.

The mechanisms underlying the many phenotypic manifestations of post-acute COVID-19 syndrome (PACS) are poorly understood. Herein, we characterized the gut microbiome in heterogeneous cohorts of subjects with PACS and developed a multi-label machine learning model for using the microbiome to predict specific symptoms. Our processed data covered 585 bacterial species and 500 microbial pathways, explaining 12.7% of the inter-individual variability in PACS. Three gut-microbiome-based enterotypes were identified in subjects with PACS and associated with different phenotypic manifestations. The trained model showed an accuracy of 0.89 in predicting individual symptoms of PACS in the test set and maintained a sensitivity of 86% and a specificity of 82% in predicting upcoming symptoms in an independent longitudinal cohort of subjects before they developed PACS. This study demonstrates that the gut microbiome is associated with phenotypic manifestations of PACS, which has potential clinical utility for the prediction and diagnosis of PACS.

RevDate: 2024-05-09
CmpDate: 2024-05-09

Fonnes S, Mollerup S, Paulsen SJ, et al (2024)

The microbiome of the appendix differs in patients with and without appendicitis: A prospective cohort study.

Surgery, 175(6):1482-1488.

BACKGROUND: Appendicitis seems to be a disease of infectious origin, but the detailed pathogenesis is unknown. We aimed to investigate the microbiome of the appendix lumen in patients with and without appendicitis, including a comparison of the subgroups of complicated versus uncomplicated appendicitis.

METHODS: This prospective observational cohort study included adult patients undergoing laparoscopic appendectomy for suspected appendicitis. According to histopathologic findings, the investigated groups consisted of patients with and without appendicitis, including subgroups of complicated versus uncomplicated appendicitis based on the surgical report. A swab of the appendix lumen was analyzed for genetic material from bacteria with shotgun metagenomics, and outcomes included analyses of microbiome diversity and differential abundance of bacteria.

RESULTS: A total of 53 swabs from patients with suspected appendicitis were analyzed: 42 with appendicitis (16 complicated) and 11 without appendicitis. When comparing patients with and without appendicitis, they were equally rich in bacteria (alpha diversity), but the microbiome composition was dissimilar between these groups (beta diversity) (P < .01). No consistent bacterial species were detected in all patients with appendicitis, but a least 3 genera (Blautia, Faecalibacterium, and Fusicatenibacter) and 2 species, Blautia faecis and Blautia wexlerae, were more abundant in patients without appendicitis. For the subgroups complicated versus uncomplicated appendicitis, both measures for microbiome diversity were similar.

CONCLUSION: The appendix microbiome composition of genetic material from bacteria in adult patients with and without appendicitis differed, but the microbiome was similar for patients with complicated versus uncomplicated appendicitis. Trial registration NCT03349814.

RevDate: 2024-05-09
CmpDate: 2024-05-09

Kirsch JM, Hryckowian AJ, BA Duerkop (2024)

A metagenomics pipeline reveals insertion sequence-driven evolution of the microbiota.

Cell host & microbe, 32(5):739-754.e4.

Insertion sequence (IS) elements are mobile genetic elements in bacterial genomes that support adaptation. We developed a database of IS elements coupled to a computational pipeline that identifies IS element insertions in the microbiota. We discovered that diverse IS elements insert into the genomes of intestinal bacteria regardless of human host lifestyle. These insertions target bacterial accessory genes that aid in their adaptation to unique environmental conditions. Using IS expansion in Bacteroides, we show that IS activity leads to the insertion of "hot spots" in accessory genes. We show that IS insertions are stable and can be transferred between humans. Extreme environmental perturbations force IS elements to fall out of the microbiota, and many fail to rebound following homeostasis. Our work shows that IS elements drive bacterial genome diversification within the microbiota and establishes a framework for understanding how strain-level variation within the microbiota impacts human health.

RevDate: 2024-05-09
CmpDate: 2024-05-09

Frayman KB, Macowan M, Caparros-Martin J, et al (2024)

The longitudinal microbial and metabolic landscape of infant cystic fibrosis: the gut-lung axis.

The European respiratory journal, 63(5): pii:13993003.02290-2023.

BACKGROUND AND AIM: In cystic fibrosis, gastrointestinal dysfunction and lower airway infection occur early and are independently associated with poorer outcomes in childhood. This study aimed to define the relationship between the microbiota at each niche during the first 2 years of life, its association with growth and airway inflammation, and explanatory features in the metabolome.

MATERIALS AND METHODS: 67 bronchoalveolar lavage fluid (BALF), 62 plasma and 105 stool samples were collected from 39 infants with cystic fibrosis between 0 and 24 months who were treated with prophylactic antibiotics. 16S rRNA amplicon and shotgun metagenomic sequencing were performed on BALF and stool samples, respectively; metabolomic analyses were performed on all sample types. Sequencing data from healthy age-matched infants were used as controls.

RESULTS: Bacterial diversity increased over the first 2 years in both BALF and stool, and microbial maturation was delayed in comparison to healthy controls from the RESONANCE cohort. Correlations between their respective abundance in both sites suggest stool may serve as a noninvasive alternative for detecting BALF Pseudomonas and Veillonella. Multisite metabolomic analyses revealed age- and growth-related changes, associations with neutrophilic airway inflammation, and a set of core systemic metabolites. BALF Pseudomonas abundance was correlated with altered stool microbiome composition and systemic metabolite alterations, highlighting a complex gut-plasma-lung interplay and new targets with therapeutic potential.

CONCLUSION: Exploration of the gut-lung microbiome and metabolome reveals diverse multisite interactions in cystic fibrosis that emerge in early life. Gut-lung metabolomic links with airway inflammation and Pseudomonas abundance warrant further investigation for clinical utility, particularly in non-expectorating patients.

RevDate: 2024-05-09
CmpDate: 2024-05-09

Nenciarini S, Renzi S, di Paola M, et al (2024)

Ascomycetes yeasts: The hidden part of human microbiome.

WIREs mechanisms of disease, 16(3):e1641.

The fungal component of the microbiota, the mycobiota, has been neglected for a long time due to its poor richness compared to bacteria. Limitations in fungal detection and taxonomic identification arise from using metagenomic approaches, often borrowed from bacteriome analyses. However, the relatively recent discoveries of the ability of fungi to modulate the host immune response and their involvement in human diseases have made mycobiota a fundamental component of the microbial communities inhabiting the human host, deserving some consideration in host-microbe interaction studies and in metagenomics. Here, we reviewed recent data on the identification of yeasts of the Ascomycota phylum across human body districts, focusing on the most representative genera, that is, Saccharomyces and Candida. Then, we explored the key factors involved in shaping the human mycobiota across the lifespan, ranging from host genetics to environment, diet, and lifestyle habits. Finally, we discussed the strengths and weaknesses of culture-dependent and independent methods for mycobiota characterization. Overall, there is still room for some improvements, especially regarding fungal-specific methodological approaches and bioinformatics challenges, which are still critical steps in mycobiota analysis, and to advance our knowledge on the role of the gut mycobiota in human health and disease. This article is categorized under: Immune System Diseases > Genetics/Genomics/Epigenetics Immune System Diseases > Environmental Factors Infectious Diseases > Environmental Factors.

RevDate: 2024-05-07

Lee KS, Landry Z, Athar A, et al (2024)

MicrobioRaman: an open-access web repository for microbiological Raman spectroscopy data.

RevDate: 2024-05-08
CmpDate: 2024-05-07

Lai Y, Tang W, Luo X, et al (2024)

Gut microbiome and metabolome to discover pathogenic bacteria and probiotics in ankylosing spondylitis.

Frontiers in immunology, 15:1369116.

OBJECTIVE: Previous research has partially revealed distinct gut microbiota in ankylosing spondylitis (AS). In this study, we performed non-targeted fecal metabolomics in AS in order to discover the microbiome-metabolome interface in AS. Based on prospective cohort studies, we further explored the impact of the tumor necrosis factor inhibitor (TNFi) on the gut microbiota and metabolites in AS.

METHODS: To further understand the gut microbiota and metabolites in AS, along with the influence of TNFi, we initiated a prospective cohort study. Fecal samples were collected from 29 patients with AS before and after TNFi therapy and 31 healthy controls. Metagenomic and metabolomic experiments were performed on the fecal samples; moreover, validation experiments were conducted based on the association between the microbiota and metabolites.

RESULTS: A total of 7,703 species were annotated using the metagenomic sequencing system and by profiling the microbial community taxonomic composition, while 50,046 metabolites were identified using metabolite profiling. Differential microbials and metabolites were discovered between patients with AS and healthy controls. Moreover, TNFi was confirmed to partially restore the gut microbiota and the metabolites. Multi-omics analysis of the microbiota and metabolites was performed to determine the associations between the differential microbes and metabolites, identifying compounds such as oxypurinol and biotin, which were correlated with the inhibition of the pathogenic bacteria Ruminococcus gnavus and the promotion of the probiotic bacteria Bacteroides uniformis. Through experimental studies, the relationship between microbes and metabolites was further confirmed, and the impact of these two types of microbes on the enterocytes and the inflammatory cytokine interleukin-18 (IL-18) was explored.

CONCLUSION: In summary, multi-omics exploration elucidated the impact of TNFi on the gut microbiota and metabolites and proposed a novel therapeutic perspective: supplementation of compounds to inhibit potential pathogenic bacteria and to promote potential probiotics, therefore controlling inflammation in AS.

RevDate: 2024-05-08
CmpDate: 2024-05-06

Liu L, Zhao M, Lang X, et al (2024)

Modified Lichong decoction intervenes in colorectal cancer by modulating the intestinal flora and the Wnt/β-catenin signaling pathway.

Journal of cancer research and clinical oncology, 150(5):234.

BACKGROUND: The pathogenesis and treatment of colorectal cancer (CRC) continue to be areas of ongoing research, especially the benefits of traditional Chinese medicine (TCM) in slowing the progression of CRC. This study was conducted to investigate the effectiveness and mechanism of action of modified Lichong decoction (MLCD) in inhibiting CRC progression.

METHODS: We established CRC animal models using azoxymethane/dextran sodium sulfate (AOM/DSS) and administered high, medium, or low doses of MLCD or mesalazine (MS) for 9 weeks to observe MLCD alleviation of CRC. The optimal MLCD dose group was then subjected to metagenomic and RNA sequencing (RNA-seq) to explore the differentially abundant flora and genes in the control, model and MLCD groups. Finally, the mechanism of action was verified using WB, qRT‒PCR, immunohistochemistry and TUNEL staining.

RESULTS: MLCD inhibited the progression of CRC, and the optimal effect was observed at high doses. MLCD regulated the structure and function of the intestinal flora by decreasing the abundance of harmful bacteria and increasing that of beneficial bacteria. The differentially expressed genes were mainly associated with the Wnt/β-catenin pathway and the cell cycle. Molecular biology analysis indicated that MLCD suppressed the Wnt/β-catenin pathway and the epithelial-mesenchymal transition (EMT), inhibited abnormal cell proliferation and promoted intestinal epithelial cell apoptosis.

CONCLUSION: MLCD mitigated the abnormal growth of intestinal epithelial cells and promoted apoptosis, thereby inhibiting the progression of CRC. This inhibition was accomplished by modifying the intestinal microbiota and disrupting the Wnt/β-catenin pathway and the EMT. Therefore, MLCD could serve as a potential component of TCM prescriptions for CRC treatment.

RevDate: 2024-05-08
CmpDate: 2024-05-06

Yahara H, Yanamoto S, Takahashi M, et al (2024)

Shotgun metagenomic analysis of saliva microbiome suggests Mogibacterium as a factor associated with chronic bacterial osteomyelitis.

PloS one, 19(5):e0302569.

Osteomyelitis of the jaw is a severe inflammatory disorder that affects bones, and it is categorized into two main types: chronic bacterial and nonbacterial osteomyelitis. Although previous studies have investigated the association between these diseases and the oral microbiome, the specific taxa associated with each disease remain unknown. In this study, we conducted shotgun metagenome sequencing (≥10 Gb from ≥66,395,670 reads per sample) of bulk DNA extracted from saliva obtained from patients with chronic bacterial osteomyelitis (N = 5) and chronic nonbacterial osteomyelitis (N = 10). We then compared the taxonomic composition of the metagenome in terms of both taxonomic and sequence abundances with that of healthy controls (N = 5). Taxonomic profiling revealed a statistically significant increase in both the taxonomic and sequence abundance of Mogibacterium in cases of chronic bacterial osteomyelitis; however, such enrichment was not observed in chronic nonbacterial osteomyelitis. We also compared a previously reported core saliva microbiome (59 genera) with our data and found that out of the 74 genera detected in this study, 47 (including Mogibacterium) were not included in the previous meta-analysis. Additionally, we analyzed a core-genome tree of Mogibacterium from chronic bacterial osteomyelitis and healthy control samples along with a reference complete genome and found that Mogibacterium from both groups was indistinguishable at the core-genome and pan-genome levels. Although limited by the small sample size, our study provides novel evidence of a significant increase in Mogibacterium abundance in the chronic bacterial osteomyelitis group. Moreover, our study presents a comparative analysis of the taxonomic and sequence abundances of all genera detected using deep salivary shotgun metagenome data. The distinct enrichment of Mogibacterium suggests its potential as a marker to distinguish between patients with chronic nonbacterial osteomyelitis and chronic bacterial osteomyelitis, particularly at the early stages when differences are unclear.

RevDate: 2024-05-08
CmpDate: 2024-05-06

Veschetti L, Paiella S, Carelli M, et al (2024)

Dental plaque microbiota sequence counts for microbial profiling and resistance genes detection.

Applied microbiology and biotechnology, 108(1):319.

Shotgun metagenomics sequencing experiments are finding a wide range of applications. Nonetheless, there are still limited guidelines regarding the number of sequences needed to acquire meaningful information for taxonomic profiling and antimicrobial resistance gene (ARG) identification. In this study, we explored this issue in the context of oral microbiota by sequencing with a very high number of sequences (~ 100 million), four human plaque samples, and one microbial community standard and by evaluating the performance of microbial identification and ARGs detection through a downsampling procedure. When investigating the impact of a decreasing number of sequences on quantitative taxonomic profiling in the microbial community standard datasets, we found some discrepancies in the identified microbial species and their abundances when compared to the expected ones. Such differences were consistent throughout downsampling, suggesting their link to taxonomic profiling methods limitations. Overall, results showed that the number of sequences has a great impact on metagenomic samples at the qualitative (i.e., presence/absence) level in terms of loss of information, especially in experiments having less than 40 million reads, whereas abundance estimation was minimally affected, with only slight variations observed in low-abundance species. The presence of ARGs was also assessed: a total of 133 ARGs were identified. Notably, 23% of them inconsistently resulted as present or absent across downsampling datasets of the same sample. Moreover, over half of ARGs were lost in datasets having less than 20 million reads. This study highlights the importance of carefully considering sequencing aspects and suggests some guidelines for designing shotgun metagenomics experiments with the final goal of maximizing oral microbiome analyses. Our findings suggest varying optimized sequence numbers according to different study aims: 40 million for microbiota profiling, 50 million for low-abundance species detection, and 20 million for ARG identification. KEY POINTS: • Forty million sequences are a cost-efficient solution for microbiota profiling • Fifty million sequences allow low-abundance species detection • Twenty million sequences are recommended for ARG identification.

RevDate: 2024-05-08
CmpDate: 2024-05-08

Oliver A, Podell S, Wegley Kelly L, et al (2024)

Enrichable consortia of microbial symbionts degrade macroalgal polysaccharides in Kyphosus fish.

mBio, 15(5):e0049624.

Coastal herbivorous fishes consume macroalgae, which is then degraded by microbes along their digestive tract. However, there is scarce genomic information about the microbiota that perform this degradation. This study explores the potential of Kyphosus gastrointestinal microbial symbionts to collaboratively degrade and ferment polysaccharides from red, green, and brown macroalgae through in silico study of carbohydrate-active enzyme and sulfatase sequences. Recovery of metagenome-assembled genomes (MAGs) from previously described Kyphosus gut metagenomes and newly sequenced bioreactor enrichments reveals differences in enzymatic capabilities between the major microbial taxa in Kyphosus guts. The most versatile of the recovered MAGs were from the Bacteroidota phylum, whose MAGs house enzyme collections able to decompose a variety of algal polysaccharides. Unique enzymes and predicted degradative capacities of genomes from the Bacillota (genus Vallitalea) and Verrucomicrobiota (order Kiritimatiellales) highlight the importance of metabolic contributions from multiple phyla to broaden polysaccharide degradation capabilities. Few genomes contain the required enzymes to fully degrade any complex sulfated algal polysaccharide alone. The distribution of suitable enzymes between MAGs originating from different taxa, along with the widespread detection of signal peptides in candidate enzymes, is consistent with cooperative extracellular degradation of these carbohydrates. This study leverages genomic evidence to reveal an untapped diversity at the enzyme and strain level among Kyphosus symbionts and their contributions to macroalgae decomposition. Bioreactor enrichments provide a genomic foundation for degradative and fermentative processes central to translating the knowledge gained from this system to the aquaculture and bioenergy sectors.IMPORTANCESeaweed has long been considered a promising source of sustainable biomass for bioenergy and aquaculture feed, but scalable industrial methods for decomposing terrestrial compounds can struggle to break down seaweed polysaccharides efficiently due to their unique sulfated structures. Fish of the genus Kyphosus feed on seaweed by leveraging gastrointestinal bacteria to degrade algal polysaccharides into simple sugars. This study reconstructs metagenome-assembled genomes for these gastrointestinal bacteria to enhance our understanding of herbivorous fish digestion and fermentation of algal sugars. Investigations at the gene level identify Kyphosus guts as an untapped source of seaweed-degrading enzymes ripe for further characterization. These discoveries set the stage for future work incorporating marine enzymes and microbial communities in the industrial degradation of algal polysaccharides.

RevDate: 2024-05-07
CmpDate: 2024-05-05

Powell AM, Ali Khan FZ, Ravel J, et al (2024)

Untangling Associations of Microbiomes of Pregnancy and Preterm Birth.

Clinics in perinatology, 51(2):425-439.

This review illuminates the complex interplay between various maternal microbiomes and their influence on preterm birth (PTB), a driving and persistent contributor to neonatal morbidity and mortality. Here, we examine the dynamics of oral, gastrointestinal (gut), placental, and vaginal microbiomes, dissecting their roles in the pathogenesis of PTB. Importantly, focusing on the vaginal microbiome and PTB, the review highlights (1) a protective role of Lactobacillus species; (2) an increased risk with select anaerobes; and (3) the influence of social health determinants on the composition of vaginal microbial communities.

RevDate: 2024-05-07
CmpDate: 2024-05-04

Morsli M, Salipante F, Magnan C, et al (2024)

Direct metagenomics investigation of non-surgical hard-to-heal wounds: a review.

Annals of clinical microbiology and antimicrobials, 23(1):39.

BACKGROUND: Non-surgical chronic wounds, including diabetes-related foot diseases (DRFD), pressure injuries (PIs) and venous leg ulcers (VLU), are common hard-to-heal wounds. Wound evolution partly depends on microbial colonisation or infection, which is often confused by clinicians, thereby hampering proper management. Current routine microbiology investigation of these wounds is based on in vitro culture, focusing only on a limited panel of the most frequently isolated bacteria, leaving a large part of the wound microbiome undocumented.

METHODS: A literature search was conducted on original studies published through October 2022 reporting metagenomic next generation sequencing (mNGS) of chronic wound samples. Studies were eligible for inclusion if they applied 16 S rRNA metagenomics or shotgun metagenomics for microbiome analysis or diagnosis. Case reports, prospective, or retrospective studies were included. However, review articles, animal studies, in vitro model optimisation, benchmarking, treatment optimisation studies, and non-clinical studies were excluded. Articles were identified in PubMed, Google Scholar, Web of Science, Microsoft Academic, Crossref and Semantic Scholar databases.

RESULTS: Of the 3,202 articles found in the initial search, 2,336 articles were removed after deduplication and 834 articles following title and abstract screening. A further 14 were removed after full text reading, with 18 articles finally included. Data were provided for 3,628 patients, including 1,535 DRFDs, 956 VLUs, and 791 PIs, with 164 microbial genera and 116 species identified using mNGS approaches. A high microbial diversity was observed depending on the geographical location and wound evolution. Clinically infected wounds were the most diverse, possibly due to a widespread colonisation by pathogenic bacteria from body and environmental microbiota. mNGS data identified the presence of virus (EBV) and fungi (Candida and Aspergillus species), as well as Staphylococcus and Pseudomonas bacteriophages.

CONCLUSION: This study highlighted the benefit of mNGS for time-effective pathogen genome detection. Despite the majority of the included studies investigating only 16 S rDNA, ignoring a part of viral, fungal and parasite colonisation, mNGS detected a large number of bacteria through the included studies. Such technology could be implemented in routine microbiology for hard-to-heal wound microbiota investigation and post-treatment wound colonisation surveillance.

RevDate: 2024-05-07
CmpDate: 2024-05-07

Liang X, Zhu Y, Liu H, et al (2024)

Nitrogen-fixing cyanobacteria enhance microbial carbon utilization by modulating the microbial community composition in paddy soils of the Mollisols region.

The Science of the total environment, 929:172609.

Nitrogen-fixing cyanobacteria (NFC) are photosynthetic prokaryotic microorganisms capable of nitrogen fixation. They can be used as biofertilizers in paddy fields, thereby improving the rice tillering capacity and yield. To reveal the microbiological mechanisms by which nitrogen-fixing cyanobacteria alter soil carbon storage, we conducted a field experiment using NFC as a partial substitute for nitrogen fertilizer in paddy fields in the Sanjiang Plain of Northeast China's Mollisols region. Using metagenomic sequencing technology and Biolog Ecoplate™ carbon matrix metabolism measurements, we explored the changes in the soil microbial community structure and carbon utilization in paddy fields. The results indicated that the replacement of nitrogen fertilizer with NFC predisposed the soil microbial community to host a great number of copiotrophic bacterial taxa, and Proteobacteria and Actinobacteria were closely associated with the metabolism of soil carbon sources. Moreover, through co-occurrence network analysis, we found that copiotrophic bacteria clustered in modules that were positively correlated with the metabolic level of carbon sources. The addition of NFC promoted the growth of copiotrophic bacteria, which increased the carbon utilization level of soil microorganisms, improved the diversity of the microbial communities, and had a potential impact on the soil carbon stock. The findings of this study are helpful for assessing the impact of NFC on the ecological function of soil microbial communities in paddy fields in the black soil area of Northeast China, which is highly important for promoting sustainable agricultural development and providing scientific reference for promoting the use of algal-derived nitrogen fertilizers.

RevDate: 2024-05-07
CmpDate: 2024-05-07

Coskun ÖK, Gomez-Saez GV, Beren M, et al (2024)

Quantifying genome-specific carbon fixation in a 750-meter deep subsurface hydrothermal microbial community.

FEMS microbiology ecology, 100(5):.

Dissolved inorganic carbon has been hypothesized to stimulate microbial chemoautotrophic activity as a biological sink in the carbon cycle of deep subsurface environments. Here, we tested this hypothesis using quantitative DNA stable isotope probing of metagenome-assembled genomes (MAGs) at multiple 13C-labeled bicarbonate concentrations in hydrothermal fluids from a 750-m deep subsurface aquifer in the Biga Peninsula (Turkey). The diversity of microbial populations assimilating 13C-labeled bicarbonate was significantly different at higher bicarbonate concentrations, and could be linked to four separate carbon-fixation pathways encoded within 13C-labeled MAGs. Microbial populations encoding the Calvin-Benson-Bassham cycle had the highest contribution to carbon fixation across all bicarbonate concentrations tested, spanning 1-10 mM. However, out of all the active carbon-fixation pathways detected, MAGs affiliated with the phylum Aquificae encoding the reverse tricarboxylic acid (rTCA) pathway were the only microbial populations that exhibited an increased 13C-bicarbonate assimilation under increasing bicarbonate concentrations. Our study provides the first experimental data supporting predictions that increased bicarbonate concentrations may promote chemoautotrophy via the rTCA cycle and its biological sink for deep subsurface inorganic carbon.

RevDate: 2024-05-06
CmpDate: 2024-05-03

Macdonald JFH, Pérez-García P, Schneider YK, et al (2024)

Community dynamics and metagenomic analyses reveal Bacteroidota's role in widespread enzymatic Fucus vesiculosus cell wall degradation.

Scientific reports, 14(1):10237.

Enzymatic degradation of algae cell wall carbohydrates by microorganisms is under increasing investigation as marine organic matter gains more value as a sustainable resource. The fate of carbon in the marine ecosystem is in part driven by these degradation processes. In this study, we observe the microbiome dynamics of the macroalga Fucus vesiculosus in 25-day-enrichment cultures resulting in partial degradation of the brown algae. Microbial community analyses revealed the phylum Pseudomonadota as the main bacterial fraction dominated by the genera Marinomonas and Vibrio. More importantly, a metagenome-based Hidden Markov model for specific glycosyl hydrolyses and sulphatases identified Bacteroidota as the phylum with the highest potential for cell wall degradation, contrary to their low abundance. For experimental verification, we cloned, expressed, and biochemically characterised two α-L-fucosidases, FUJM18 and FUJM20. While protein structure predictions suggest the highest similarity to a Bacillota origin, protein-protein blasts solely showed weak similarities to defined Bacteroidota proteins. Both enzymes were remarkably active at elevated temperatures and are the basis for a potential synthetic enzyme cocktail for large-scale algal destruction.

RevDate: 2024-05-04
CmpDate: 2024-05-01

Guadalupe JJ, Pazmiño-Vela M, Pozo G, et al (2024)

Metagenomic analysis of microbial consortia native to the Amazon, Highlands, and Galapagos regions of Ecuador with potential for wastewater remediation.

Environmental microbiology reports, 16(3):e13272.

Native microbial consortia have been proposed for biological wastewater treatment, but their diversity and function remain poorly understood. This study investigated three native microalgae-bacteria consortia collected from the Amazon, Highlands, and Galapagos regions of Ecuador to assess their metagenomes and wastewater remediation potential. The consortia were evaluated for 12 days under light (LC) and continuous dark conditions (CDC) to measure their capacity for nutrient and organic matter removal from synthetic wastewater (SWW). Overall, all three consortia demonstrated higher nutrient removal efficiencies under LC than CDC, with the Amazon and Galapagos consortia outperforming the Highlands consortium in nutrient removal capabilities. Despite differences in α- and β-diversity, microbial species diversity within and between consortia did not directly correlate with their nutrient removal capabilities. However, all three consortia were enriched with core taxonomic groups associated with wastewater remediation activities. Our analyses further revealed higher abundances for nutrient removing microorganisms in the Amazon and Galapagos consortia compared with the Highland consortium. Finally, this study also uncovered the contribution of novel microbial groups that enhance wastewater bioremediation processes. These groups have not previously been reported as part of the core microbial groups commonly found in wastewater communities, thereby highlighting the potential of investigating microbial consortia isolated from ecosystems of megadiverse countries like Ecuador.

RevDate: 2024-05-03
CmpDate: 2024-05-01

Kawser AQMR, Hoque MN, Rahman MS, et al (2024)

Unveiling the gut bacteriome diversity and distribution in the national fish hilsa (Tenualosa ilisha) of Bangladesh.

PloS one, 19(5):e0303047.

The field of fish microbiome research has rapidly been advancing, primarily focusing on farmed or laboratory fish species rather than natural or marine fish populations. This study sought to reveal the distinctive gut bacteriome composition and diversity within the anadromous fish species Tenualosa ilisha (hilsa), which holds the status of being the national fish of Bangladesh. We conducted an analysis on 15 gut samples obtained from 15 individual hilsa fishes collected from three primary habitats (e.g., freshwater = 5, brackish water = 5 and marine water = 5) in Bangladesh. The analysis utilized metagenomics based on 16S rRNA gene sequencing targeting the V3-V4 regions. Our comprehensive identification revealed a total of 258 operational taxonomic units (OTUs). The observed OTUs were represented by six phyla, nine classes, 19 orders, 26 families and 40 genera of bacteria. Our analysis unveiled considerable taxonomic differences among the habitats (freshwater, brackish water, and marine water) of hilsa fishes, as denoted by a higher level of shared microbiota (p = 0.007, Kruskal-Wallis test). Among the identified genera in the gut of hilsa fishes, including Vagococcus, Morganella, Enterobacter, Plesiomonas, Shigella, Clostridium, Klebsiella, Serratia, Aeromonas, Macrococcus, Staphylococcus, Proteus, and Hafnia, several are recognized as fish probiotics. Importantly, some bacterial genera such as Sinobaca, Synechococcus, Gemmata, Serinicoccus, Saccharopolyspora, and Paulinella identified in the gut of hilsa identified in this study have not been reported in any aquatic or marine fish species. Significantly, we observed that 67.50% (27/40) of bacterial genera were found to be common among hilsa fishes across all three habitats. Our findings offer compelling evidence for the presence of both exclusive and communal bacteriomes within the gut of hilsa fishes, exhibiting potential probiotic properties. These observations could be crucial for guiding future microbiome investigations in this economically significant fish species.

RevDate: 2024-05-06
CmpDate: 2024-05-06

Zhanbo Q, Jing Z, Shugao H, et al (2024)

Age and aging process alter the gut microbes.

Aging, 16(8):6839-6851.

BACKGROUND: Gut microbes and age are both factors that influence the development of disease. The community structure of gut microbes is affected by age.

OBJECTIVE: To plot time-dependent gut microbe profiles in individuals over 45 years old and explore the correlation between age and gut microbes.

METHODS: Fecal samples were collected from 510 healthy individuals over 45 years old. Shannon index, Simpson index, Ace index, etc. were used to analyze the diversity of gut microbes. The beta diversity analysis, including non-metric multidimensional scaling (NMDS), was used to analyze community distribution. Linear discriminant analysis (LDA) and random forest (RF) algorithm were used to analyze the differences of gut microbes. Trend analysis was used to plot the abundances of characteristic gut microbes in different ages.

RESULTS: The individuals aged 45-49 had the highest richness of gut bacteria. Fifteen characteristic gut microbes, including Siphoviridae and Bifidobacterium breve, were screened by RF algorithm. The abundance of Ligiactobacillus and Microviridae were higher in individuals older than 65 years. Moreover, the abundance of Blautia_A massiliensis, Lubbockvirus and Enterocloster clostridioformis decreased with age and the abundance of Klebsiella variicola and Prevotella increased with age. The functional genes, such as human diseases and aging, were significantly different among different aged individuals.

CONCLUSIONS: The individuals in different ages have characteristic gut microbes. The changes in community structure of gut microbes may be related to age-induced diseases.

RevDate: 2024-05-06
CmpDate: 2024-05-06

Zeng N, Wu F, Lu J, et al (2024)

High-fat diet impairs gut barrier through intestinal microbiota-derived reactive oxygen species.

Science China. Life sciences, 67(5):879-891.

Gut barrier disruption is a key event in bridging gut microbiota dysbiosis and high-fat diet (HFD)-associated metabolic disorders. However, the underlying mechanism remains elusive. In the present study, by comparing HFD- and normal diet (ND)-treated mice, we found that the HFD instantly altered the composition of the gut microbiota and subsequently damaged the integrity of the gut barrier. Metagenomic sequencing revealed that the HFD upregulates gut microbial functions related to redox reactions, as confirmed by the increased reactive oxygen species (ROS) levels in fecal microbiota incubation in vitro and in the lumen, which were detected using in vivo fluorescence imaging. This microbial ROS-producing capability induced by HFD can be transferred through fecal microbiota transplantation (FMT) into germ-free (GF) mice, downregulating the gut barrier tight junctions. Similarly, mono-colonizing GF mice with an Enterococcus strain excelled in ROS production, damaged the gut barrier, induced mitochondrial malfunction and apoptosis of the intestinal epithelial cells, and exacerbated fatty liver, compared with other low-ROS-producing Enterococcus strains. Oral administration of recombinant high-stability-superoxide dismutase (SOD) significantly reduced intestinal ROS, protected the gut barrier, and improved fatty liver against the HFD. In conclusion, our study suggests that extracellular ROS derived from gut microbiota play a pivotal role in HFD-induced gut barrier disruption and is a potential therapeutic target for HFD-associated metabolic diseases.

RevDate: 2024-05-06
CmpDate: 2024-05-06

Yao T, Wang H, Lin K, et al (2024)

Exercise-induced microbial changes in preventing type 2 diabetes.

Science China. Life sciences, 67(5):892-899.

The metabolic benefits associated with long-term physical activity are well appreciated and growing evidence suggests that it involves the gut microbiota. Here we re-evaluated the link between exercise-induced microbial changes and those associated with prediabetes and diabetes. We found that the relative abundances of substantial amounts of diabetes-associated metagenomic species associated negatively with physical fitness in a Chinese athlete students cohort. We additionally showed that those microbial changes correlated more with handgrip strength, a simple but valuable biomarker suggestive of the diabetes states, than maximum oxygen intake, one of the key surrogates for endurance training. Moreover, the causal relationships among exercise, risks for diabetes, and gut microbiota were explored based on mediation analysis. We propose that the protective roles of exercise against type 2 diabetes are mediated, at least partly, by the gut microbiota.

RevDate: 2024-05-03
CmpDate: 2024-05-01

Chen P, Chen H, Liu Z, et al (2024)

Fungal-bacteria interactions provide shelter for bacteria in Caesarean section scar diverticulum.

eLife, 12:.

Caesarean section scar diverticulum (CSD) is a significant cause of infertility among women who have previously had a Caesarean section, primarily due to persistent inflammatory exudation associated with this condition. Even though abnormal bacterial composition is identified as a critical factor leading to this chronic inflammation, clinical data suggest that a long-term cure is often unattainable with antibiotic treatment alone. In our study, we employed metagenomic analysis and mass spectrometry techniques to investigate the fungal composition in CSD and its interaction with bacteria. We discovered that local fungal abnormalities in CSD can disrupt the stability of the bacterial population and the entire microbial community by altering bacterial abundance via specific metabolites. For instance, Lachnellula suecica reduces the abundance of several Lactobacillus spp., such as Lactobacillus jensenii, by diminishing the production of metabolites like Goyaglycoside A and Janthitrem E. Concurrently, Clavispora lusitaniae and Ophiocordyceps australis can synergistically impact the abundance of Lactobacillus spp. by modulating metabolite abundance. Our findings underscore that abnormal fungal composition and activity are key drivers of local bacterial dysbiosis in CSD.

RevDate: 2024-04-30
CmpDate: 2024-04-30

Kobayashi D, Inoue Y, Suzuki R, et al (2024)

Identification and epidemiological study of an uncultured flavivirus from ticks using viral metagenomics and pseudoinfectious viral particles.

Proceedings of the National Academy of Sciences of the United States of America, 121(19):e2319400121.

During their blood-feeding process, ticks are known to transmit various viruses to vertebrates, including humans. Recent viral metagenomic analyses using next-generation sequencing (NGS) have revealed that blood-feeding arthropods like ticks harbor a large diversity of viruses. However, many of these viruses have not been isolated or cultured, and their basic characteristics remain unknown. This study aimed to present the identification of a difficult-to-culture virus in ticks using NGS and to understand its epidemic dynamics using molecular biology techniques. During routine tick-borne virus surveillance in Japan, an unknown flaviviral sequence was detected via virome analysis of host-questing ticks. Similar viral sequences have been detected in the sera of sika deer and wild boars in Japan, and this virus was tentatively named the Saruyama virus (SAYAV). Because SAYAV did not propagate in any cultured cells tested, single-round infectious virus particles (SRIP) were generated based on its structural protein gene sequence utilizing a yellow fever virus-based replicon system to understand its nationwide endemic status. Seroepidemiological studies using SRIP as antigens have demonstrated the presence of neutralizing antibodies against SAYAV in sika deer and wild boar captured at several locations in Japan, suggesting that SAYAV is endemic throughout Japan. Phylogenetic analyses have revealed that SAYAV forms a sister clade with the Orthoflavivirus genus, which includes important mosquito- and tick-borne pathogenic viruses. This shows that SAYAV evolved into a lineage independent of the known orthoflaviviruses. This study demonstrates a unique approach for understanding the epidemiology of uncultured viruses by combining viral metagenomics and pseudoinfectious viral particles.

RevDate: 2024-05-03
CmpDate: 2024-04-30

Ishnaiwer M, Le Bastard Q, Naour M, et al (2024)

Efficacy of an inulin-based treatment on intestinal colonization by multidrug-resistant E. coli: insight into the mechanism of action.

Gut microbes, 16(1):2347021.

Inulin, an increasingly studied dietary fiber, alters intestinal microbiota. The aim of this study was to assess whether inulin decreases intestinal colonization by multidrug resistant E. coli and to investigate its potential mechanisms of action. Mice with amoxicillin-induced intestinal dysbiosis mice were inoculated with extended spectrum beta-lactamase producing E. coli (ESBL-E. coli). The combination of inulin and pantoprazole (IP) significantly reduced ESBL-E. coli fecal titers, whereas pantoprazole alone did not and inulin had a delayed and limited effect. Fecal microbiome was assessed using shotgun metagenomic sequencing and qPCR. The efficacy of IP was predicted by increased abundance of 74 taxa, including two species of Adlercreutzia. Preventive treatments with A. caecimuris or A. muris also reduced ESBL-E. coli fecal titers. Fecal microbiota of mice effectively treated by IP was enriched in genes involved in inulin catabolism, production of propionate and expression of beta-lactamases. They also had increased beta-lactamase activity and decreased amoxicillin concentration. These results suggest that IP act through production of propionate and degradation of amoxicillin by the microbiota. The combination of pantoprazole and inulin is a potential treatment of intestinal colonization by multidrug-resistant E. coli. The ability of prebiotics to promote propionate and/or beta-lactamase producing bacteria may be used as a screening tool to identify potential treatments of intestinal colonization by multidrug resistant Enterobacterales.

RevDate: 2024-05-03
CmpDate: 2024-05-03

Kharey GS, Palace V, Whyte L, et al (2024)

Native freshwater lake microbial community response to an in situ experimental dilbit spill.

FEMS microbiology ecology, 100(5):.

With the increase in crude oil transport throughout Canada, the potential for spills into freshwater ecosystems has increased and additional research is needed in these sensitive environments. Large enclosures erected in a lake were used as mesocosms for this controlled experimental dilbit (diluted bitumen) spill under ambient environmental conditions. The microbial response to dilbit, the efficacy of standard remediation protocols on different shoreline types commonly found in Canadian freshwater lakes, including a testing of a shoreline washing agent were all evaluated. We found that the native microbial community did not undergo any significant shifts in composition after exposure to dilbit or the ensuing remediation treatments. Regardless of the treatment, sample type (soil, sediment, or water), or type of associated shoreline, the community remained relatively consistent over a 3-month monitoring period. Following this, metagenomic analysis of polycyclic aromatic and alkane hydrocarbon degradation mechanisms also showed that while many key genes identified in PAH and alkane biodegradation were present, their abundance did not change significantly over the course of the experiment. These results showed that the native microbial community present in a pristine freshwater lake has the prerequisite mechanisms for hydrocarbon degradation in place, and combined with standard remediation practices in use in Canada, has the genetic potential and resilience to potentially undertake bioremediation.

RevDate: 2024-05-02
CmpDate: 2024-05-02

Kharey GS, Palace V, Whyte L, et al (2024)

Influence of heavy Canadian crude oil on pristine freshwater boreal lake ecosystems in an experimental oil spill.

FEMS microbiology ecology, 100(5):.

The overall impact of a crude oil spill into a pristine freshwater environment in Canada is largely unknown. To evaluate the impact on the native microbial community, a large-scale in situ model experimental spill was conducted to assess the potential role of the natural community to attenuate hydrocarbons. A small volume of conventional heavy crude oil (CHV) was introduced within contained mesocosm enclosures deployed on the shoreline of a freshwater lake. The oil was left to interact with the shoreline for 72 h and then free-floating oil was recovered using common oil spill response methods (i.e. freshwater flushing and capture on oleophilic absorptive media). Residual polycyclic aromatic hydrocarbon (PAH) concentrations returned to near preoiling concentrations within 2 months, while the microbial community composition across the water, soil, and sediment matrices of the enclosed oligotrophic freshwater ecosystems did not shift significantly over this period. Metagenomic analysis revealed key polycyclic aromatic and alkane degradation mechanisms also did not change in their relative abundance over the monitoring period. These trends suggest that for small spills (<2 l of oil per 15 m2 of surface freshwater), physical oil recovery reduces polycyclic aromatic hydrocarbon concentrations to levels tolerated by the native microbial community. Additionally, the native microbial community present in the monitored pristine freshwater ecosystem possesses the appropriate hydrocarbon degradation mechanisms without prior challenge by hydrocarbon substrates. This study corroborated trends found previously (Kharey et al. 2024) toward freshwater hydrocarbon degradation in an environmentally relevant scale and conditions on the tolerance of residual hydrocarbons in situ.

RevDate: 2024-05-02
CmpDate: 2024-05-02

Sorouri B, Scales NC, Gaut BS, et al (2024)

Sphingomonas clade and functional distribution with simulated climate change.

Microbiology spectrum, 12(5):e0023624.

Microbes are essential for the functioning of all ecosystems, and as global warming and anthropogenic pollution threaten ecosystems, it is critical to understand how microbes respond to these changes. We investigated the climate response of Sphingomonas, a widespread gram-negative bacterial genus, during an 18-month microbial community reciprocal transplant experiment across a Southern California climate gradient. We hypothesized that after 18 months, the transplanted Sphingomonas clade and functional composition would correspond with site conditions and reflect the Sphingomonas composition of native communities. We extracted Sphingomonas sequences from metagenomic data across the gradient and assessed their clade and functional composition. Representatives of at least 12 major Sphingomonas clades were found at varying relative abundances along the climate gradient, and transplanted Sphingomonas clade composition shifted after 18 months. Site had a significant effect (PERMANOVA; P < 0.001) on the distribution of both Sphingomonas functional (R[2] = 0.465) and clade composition (R[2] = 0.400), suggesting that Sphingomonas composition depends on climate parameters. Additionally, for both Sphingomonas clade and functional composition, ordinations revealed that the transplanted communities shifted closer to the native Sphingomonas composition of the grassland site compared with the site they were transplanted into. Overall, our results indicate that climate and substrate collectively determine Sphingomonas clade and functional composition.IMPORTANCESphingomonas is the most abundant gram-negative bacterial genus in litter-degrading microbial communities of desert, grassland, shrubland, and forest ecosystems in Southern California. We aimed to determine whether Sphingomonas responds to climate change in the same way as gram-positive bacteria and whole bacterial communities in these ecosystems. Within Sphingomonas, both clade composition and functional genes shifted in response to climate and litter chemistry, supporting the idea that bacteria respond similarly to climate at different scales of genetic variation. This understanding of how microbes respond to perturbation across scales may aid in future predictions of microbial responses to climate change.

RevDate: 2024-05-02
CmpDate: 2024-05-02

Lee D, Braly K, Nuding M, et al (2024)

Reverse-engineered exclusive enteral nutrition in pediatric Crohn's disease: A pilot trial.

Journal of pediatric gastroenterology and nutrition, 78(5):1135-1142.

BACKGROUND: In pediatric Crohn's disease (CD), commercial formulas used as exclusive enteral nutrition (EEN) are effective at inducing remission. This study aims to assess the impact of a whole-food blended smoothie as EEN on CD activity and the intestinal microbiome.

METHODS: A 4-week prospective trial assessed the impact of EEN with a whole-food smoothie on newly diagnosed mild-to-moderate active pediatric CD. The smoothie with a multivitamin were developed to meet age-appropriate nutritional requirements. Assessment over 4 weeks included Pediatric Crohn's Disease Activity Index (PCDAI), serum laboratories, fecal calprotectin (FCP), and stool collection for metagenomic shotgun sequencing and microbiota composition analysis. Clinical remission was defined as PCDAI ≤ 10 at week 4.

RESULTS: Ten participants were enrolled with median age 14.5 years, and 8 completed the trial. Baseline mean PCDAI was 26.3 ± 9.1 and mean FCP 1149 ± 718 µg/g. At week 4, 80% of participants achieved clinical remission. FCP decreased by over half in 60% of participants, with FCP below 250 µg/g in 60% and below 100 µg/g in 40%. Microbiome analysis showed a significant increase in species richness over 4 weeks (p = 0.01). Compared to baseline, the relative abundance at week 2 and at week 4 was significantly increased for Bifidobacterium and Streptococcus and decreased for Blautia (p < 0.05 for all).

CONCLUSION: A whole-food blended smoothie was effective for inducing clinical remission and decreasing FCP in pediatric CD similar to commercial EEN formulas. Further research may give insight into data-driven whole-food dietary approaches for CD management.

CLINICALTRIALS: gov NCT03508193.

RevDate: 2024-05-02
CmpDate: 2024-05-02

Aljabr W, Dandachi I, Abbas B, et al (2024)

Metagenomic next-generation sequencing of nasopharyngeal microbiota in COVID-19 patients with different disease severities.

Microbiology spectrum, 12(5):e0416623.

Throughout the COVID-19 pandemic, extensive research has been conducted on SARS-COV-2 to elucidate its genome, prognosis, and possible treatments. However, few looked at the microbial markers that could be explored in infected patients and that could predict possible disease severity. The aim of this study is to compare the nasopharyngeal microbiota of healthy subjects, moderate, under medication, and recovered SARS-COV-2 patients. In 2020, 38 nasopharyngeal swabs were collected from 6 healthy subjects, 14 moderates, 10 under medication and 8 recovered SARS-COV-2 patients at the Prince Mohammed Bin Abdulaziz Hospital Riyadh. Metatranscriptomic sequencing was performed using Minion Oxford nanopore sequencing. No significant difference in alpha as well as beta diversity was observed among all four categories. Nevertheless, we have found that Streptococcus spp including Streptococcus pneumoniae and Streptococcus thermophilus were among the top 15 most abundant species detected in COVID-19 patients but not in healthy subjects. The genus Staphylococcus was found to be associated with COVID-19 patients compared to healthy subjects. Furthermore, the abundance of Leptotrichia was significantly higher in healthy subjects compared to recovered patients. Corynebacterium on the other hand, was associated with under-medication patients. Taken together, our study revealed no differences in the overall microbial composition between healthy subjects and COVID-19 patients. Significant differences were seen only at specific taxonomic level. Future studies should explore the nasopharyngeal microbiota between controls and COVID-19 patients while controlling for confounders including age, gender, and comorbidities; since these latter could affect the results and accordingly the interpretation.IMPORTANCEIn this work, no significant difference in the microbial diversity was seen between healthy subjects and COVID-19 patients. Changes in specific taxa including Leptotrichia, Staphylococcus, and Corynebacterium were only observed. Leptotrichia was significantly higher in healthy subjects, whereas Staphylococcus and Corynebacterium were mostly associated with COVID-19, and specifically with under-medication SARS-COV-2 patients, respectively. Although the COVID-19 pandemic has ended, the SARS-COV-2 virus is continuously evolving and the emergence of new variants causing more severe disease should be always kept in mind. Microbial markers in SARS-COV-2 infected patients can be useful in the early suspicion of the disease, predicting clinical outcomes, framing hospital and intensive care unit admission as well as, risk stratification. Data on which microbial marker to tackle is still controversial and more work is needed, hence the importance of this study.

RevDate: 2024-05-02
CmpDate: 2024-05-02

Zhao Z, Baltar F, GJ Herndl (2024)

Decoupling between the genetic potential and the metabolic regulation and expression in microbial organic matter cleavage across microbiomes.

Microbiology spectrum, 12(5):e0303623.

UNLABELLED: Metagenomics, metatranscriptomics, and metaproteomics are used to explore the microbial capability of enzyme secretion, but the links between protein-encoding genes and corresponding transcripts/proteins across ecosystems are underexplored. By conducting a multi-omics comparison focusing on key enzymes (carbohydrate-active enzymes [CAZymes] and peptidases) cleaving the main biomolecules across distinct microbiomes living in the ocean, soil, and human gut, we show that the community structure, functional diversity, and secretion mechanisms of microbial secretory CAZymes and peptidases vary drastically between microbiomes at metagenomic, metatranscriptomic, and metaproteomic levels. Such variations lead to decoupled relationships between CAZymes and peptidases from genetic potentials to protein expressions due to the different responses of key players toward organic matter sources and concentrations. Our results highlight the need for systematic analysis of the factors shaping patterns of microbial cleavage on organic matter to better link omics data to ecosystem processes.

IMPORTANCE: Omics tools are used to explore adaptive mechanism of microbes in diverse systems, but the advantages and limitations of different omics tools remain skeptical. Here, we reported distinct profiles in microbial secretory enzyme composition revealed by different omics methods. In general, the predicted function from metagenomic analysis decoupled from the expression of corresponding transcripts/proteins. Linking omics results to taxonomic origin, functional capability, substrate specificity, secretion preference, and enzymatic activity measurement suggested the substrate's source, concentration and stoichiometry impose strong filtering on the expression of extracellular enzymes, which may overwrite the genetic potentials. Our results present an integrated perspective on the need for multi-dimensional characterization of microbial adaptation in a changing environment.

RevDate: 2024-05-02
CmpDate: 2024-05-02

Blais M-A, Vincent WF, Vigneron A, et al (2024)

Diverse winter communities and biogeochemical cycling potential in the under-ice microbial plankton of a subarctic river-to-sea continuum.

Microbiology spectrum, 12(5):e0416023.

UNLABELLED: Winter conditions greatly alter the limnological properties of lotic ecosystems and the availability of nutrients, carbon, and energy resources for microbial processes. However, the composition and metabolic capabilities of winter microbial communities are still largely uncharacterized. Here, we sampled the winter under-ice microbiome of the Great Whale River (Nunavik, Canada) and its discharge plume into Hudson Bay. We used a combination of 16S and 18S rRNA gene amplicon analysis and metagenomic sequencing to evaluate the size-fractionated composition and functional potential of the microbial plankton. These under-ice communities were diverse in taxonomic composition and metabolically versatile in terms of energy and carbon acquisition, including the capacity to carry out phototrophic processes and degrade aromatic organic matter. Limnological properties, community composition, and metabolic potential differed between shallow and deeper sites in the river, and between fresh and brackish water in the vertical profile of the plume. Community composition also varied by size fraction, with a greater richness of prokaryotes in the larger size fraction (>3 µm) and of microbial eukaryotes in the smaller size fraction (0.22-3 µm). The freshwater communities included cosmopolitan bacterial genera that were previously detected in the summer, indicating their persistence over time in a wide range of physico-chemical conditions. These observations imply that the microbial communities of subarctic rivers and their associated discharge plumes retain a broad taxonomic and functional diversity throughout the year and that microbial processing of complex terrestrial materials persists beneath the ice during the long winter season.

IMPORTANCE: Microbiomes vary over multiple timescales, with short- and long-term changes in the physico-chemical environment. However, there is a scarcity of data and understanding about the structure and functioning of aquatic ecosystems during winter relative to summer. This is especially the case for seasonally ice-covered rivers, limiting our understanding of these ecosystems that are common throughout the boreal, subpolar, and polar regions. Here, we examined the winter under-ice microbiome of a Canadian subarctic river and its entry to the sea to characterize the taxonomic and functional features of the microbial community. We found substantial diversity in both composition and functional capabilities, including the capacity to degrade complex terrestrial compounds, despite the constraints imposed by a prolonged seasonal ice-cover and near-freezing water temperatures. This study indicates the ecological complexity and importance of winter microbiomes in ice-covered rivers and the coastal marine environment that they discharge into.

RevDate: 2024-05-02
CmpDate: 2024-05-02

Zhu K, Jin Y, Zhao Y, et al (2024)

Proteomic scrutiny of nasal microbiomes: implications for the clinic.

Expert review of proteomics, 21(4):169-179.

INTRODUCTION: The nasal cavity is the initial site of the human respiratory tract and is one of the habitats where microorganisms colonize. The findings from a growing number of studies have shown that the nasal microbiome is an important factor for human disease and health. 16S rRNA sequencing and metagenomic next-generation sequencing (mNGS) are the most commonly used means of microbiome evaluation. Among them, 16S rRNA sequencing is the primary method used in previous studies of nasal microbiomes. However, neither 16S rRNA sequencing nor mNGS can be used to analyze the genes specifically expressed by nasal microorganisms and their functions. This problem can be addressed by proteomic analysis of the nasal microbiome.

AREAS COVERED: In this review, we summarize current advances in research on the nasal microbiome, introduce the methods for proteomic evaluation of the nasal microbiome, and focus on the important roles of proteomic evaluation of the nasal microbiome in the diagnosis and treatment of related diseases.

EXPERT OPINION: The detection method for microbiome-expressed proteins is known as metaproteomics. Metaproteomic analysis can help us dig deeper into the nasal microbiomes and provide new targets and ideas for clinical diagnosis and treatment of many nasal dysbiosis-related diseases.

RevDate: 2024-05-02
CmpDate: 2024-05-02

Pan SY, Zhou CB, Deng JW, et al (2024)

The effects of pks[+] Escherichia coli and bile acid in colorectal tumorigenesis among people with cholelithiasis or cholecystectomy.

Journal of gastroenterology and hepatology, 39(5):868-879.

BACKGROUND AND AIM: Patients with cholelithiasis (CL) or cholecystectomy (CE) would have more chances of getting colorectal adenoma (CRA) or cancer (CRC). We aimed to figure out the effects of gut microbiota and bile acid on colorectal neoplasm in CL and CE patients.

METHODS: This was a retrospective observational study that recruited 514 volunteers, including 199 people with normal gallbladders (normal), 152 CL, and 163 CE patients. Discovery cohort was established to explore the difference in gut microbiota through 16S rRNA and metagenomics sequencing. Validation cohort aimed to verify the results through quantitative polymerase chain reaction (qPCR).

RESULTS: Significant enrichment of Escherichia coli was found in patients with cholelithiasis or cholecystectomy both in the discovery cohort (16S rRNA sequencing, PNormal-CL = 0.013, PNormal-CE = 0.042; metagenomics sequencing, PNormal-CE = 0.026) and validation cohort (PNormal-CL < 0.0001, PNormal-CE < 0.0001). Pks[+] E. coli was found enriched in CL and CE patients through qPCR (in discovery cohort: PNormal-CE = 0.018; in validation cohort: PNormal-CL < 0.0001, PNormal-CE < 0.0001). The differences in bile acid metabolism were found both through Tax4Fun analysis of 16S rRNA sequencing (Ko00120, primary bile acid biosynthesis, PNormal-CE = 0.014; Ko00121, secondary bile acid biosynthesis, PNormal-CE = 0.010) and through metagenomics sequencing (map 00121, PNormal-CE = 0.026). The elevation of serum total bile acid of CE patients was also found in validation cohort (PNormal-CE < 0.0001). The level of serum total bile acid was associated with the relative abundance of pks[+] E. coli (r = 0.1895, P = 0.0012).

CONCLUSIONS: E. coli, especially pks[+] species, was enriched in CL and CE patients. Pks[+] E. coli and bile acid metabolism were found associated with CRA and CRC in people after cholecystectomy.

RevDate: 2024-05-01
CmpDate: 2024-04-30

Shi J, Li Z, Jia L, et al (2024)

Castration alters the ileum microbiota of Holstein bulls and promotes beef flavor compounds.

BMC genomics, 25(1):426.

BACKGROUND: In the beef industry, bull calves are usually castrated to improve flavor and meat quality; however, this can reduce their growth and slaughter performance. The gut microbiota is known to exert a significant influence on growth and slaughter performance. However, there is a paucity of research investigating the impact of castration on gut microbiota composition and its subsequent effects on slaughter performance and meat flavor.

RESULT: The objective of this study was to examine the processes via which castration hinders slaughter productivity and enhances meat quality. Bull and castrated calves were maintained under the same management conditions, and at slaughter, meat quality was assessed, and ileum and epithelial tissue samples were obtained. The research employed metagenomic sequencing and non-targeted metabolomics techniques to investigate the makeup of the microbiota and identify differential metabolites. The findings of this study revealed the Carcass weight and eye muscle area /carcass weight in the bull group were significantly higher than those in the steer group. There were no significant differences in the length, width, and crypt depth of the ileum villi between the two groups. A total of 53 flavor compounds were identified in the two groups of beef, of which 16 were significantly higher in the steer group than in the bull group, and 5 were significantly higher in the bull group than in the steer group. In addition, bacteria, Eukaryota, and virus species were significantly separated between the two groups. The lipid metabolism pathways of α-linolenic acid, linoleic acid, and unsaturated fatty acids were significantly enriched in the Steers group. Compared with the steer group, the organic system pathway is significantly enriched in the bull group. The study also found that five metabolites (LPC (0:0/20:3), LPC (20:3/0:0), LPE (0:0/22:5), LPE (22:5/0:0), D-Mannosamine), and three species (s_Cloning_vector_Hsp70_LexA-HP1, s_Bacteroides_Coprophilus_CAG: 333, and s_Clostridium_nexile-CAG: 348) interfere with each other and collectively have a positive impact on the flavor compounds of beef.

CONCLUSIONS: These findings provide a basic understanding that under the same management conditions, castration does indeed reduce the slaughter performance of bulls and improve the flavor of beef. Microorganisms and metabolites contribute to these changes through interactions.

RevDate: 2024-05-01
CmpDate: 2024-04-30

Forry SP, Servetas SL, Kralj JG, et al (2024)

Variability and bias in microbiome metagenomic sequencing: an interlaboratory study comparing experimental protocols.

Scientific reports, 14(1):9785.

Several studies have documented the significant impact of methodological choices in microbiome analyses. The myriad of methodological options available complicate the replication of results and generally limit the comparability of findings between independent studies that use differing techniques and measurement pipelines. Here we describe the Mosaic Standards Challenge (MSC), an international interlaboratory study designed to assess the impact of methodological variables on the results. The MSC did not prescribe methods but rather asked participating labs to analyze 7 shared reference samples (5 × human stool samples and 2 × mock communities) using their standard laboratory methods. To capture the array of methodological variables, each participating lab completed a metadata reporting sheet that included 100 different questions regarding the details of their protocol. The goal of this study was to survey the methodological landscape for microbiome metagenomic sequencing (MGS) analyses and the impact of methodological decisions on metagenomic sequencing results. A total of 44 labs participated in the MSC by submitting results (16S or WGS) along with accompanying metadata; thirty 16S rRNA gene amplicon datasets and 14 WGS datasets were collected. The inclusion of two types of reference materials (human stool and mock communities) enabled analysis of both MGS measurement variability between different protocols using the biologically-relevant stool samples, and MGS bias with respect to ground truth values using the DNA mixtures. Owing to the compositional nature of MGS measurements, analyses were conducted on the ratio of Firmicutes: Bacteroidetes allowing us to directly apply common statistical methods. The resulting analysis demonstrated that protocol choices have significant effects, including both bias of the MGS measurement associated with a particular methodological choices, as well as effects on measurement robustness as observed through the spread of results between labs making similar methodological choices. In the analysis of the DNA mock communities, MGS measurement bias was observed even when there was general consensus among the participating laboratories. This study was the result of a collaborative effort that included academic, commercial, and government labs. In addition to highlighting the impact of different methodological decisions on MGS result comparability, this work also provides insights for consideration in future microbiome measurement study design.

RevDate: 2024-05-01
CmpDate: 2024-04-29

Ma W, Wang Y, Nguyen LH, et al (2024)

Gut microbiome composition and metabolic activity in women with diverticulitis.

Nature communications, 15(1):3612.

The etiopathogenesis of diverticulitis, among the most common gastrointestinal diagnoses, remains largely unknown. By leveraging stool collected within a large prospective cohort, we performed shotgun metagenomic sequencing and untargeted metabolomics profiling among 121 women diagnosed with diverticulitis requiring antibiotics or hospitalizations (cases), matched to 121 women without diverticulitis (controls) according to age and race. Overall microbial community structure and metabolomic profiles differed in diverticulitis cases compared to controls, including enrichment of pro-inflammatory Ruminococcus gnavus, 1,7-dimethyluric acid, and histidine-related metabolites, and depletion of butyrate-producing bacteria and anti-inflammatory ceramides. Through integrated multi-omic analysis, we detected covarying microbial and metabolic features, such as Bilophila wadsworthia and bile acids, specific to diverticulitis. Additionally, we observed that microbial composition modulated the protective association between a prudent fiber-rich diet and diverticulitis. Our findings offer insights into the perturbations in inflammation-related microbial and metabolic signatures associated with diverticulitis, supporting the potential of microbial-based diagnostics and therapeutic targets.

RevDate: 2024-05-01
CmpDate: 2024-05-01

Yi S, Song H, Kim WH, et al (2024)

Dynamics of microbiota and antimicrobial resistance in on-farm dairy processing plants using metagenomic and culture-dependent approaches.

International journal of food microbiology, 417:110704.

On-farm dairy processing plants, which are situated close to farms and larger dairy processing facilities, face unique challenges in maintaining environmental hygiene. This can impact various stages of dairy processing. These plants operate on smaller scales and use Low-Temperature-Long-Time (LTLT) pasteurization, making them more susceptible to microbial contamination through direct and indirect contact. Antimicrobial-resistant bacteria found on dairy farms pose risks to human health by potentially transferring resistance via dairy products. Our study aimed to investigate microbial distribution and antimicrobial resistance at four key stages: the farm, pre-pasteurization, post-pasteurization, and processing environments. We assessed microbial distribution by quantifying indicator bacteria and conducting metagenomic analysis. Antimicrobial resistance was examined by identifying resistance phenotypes and detecting resistance genes in bacterial isolates and metagenomes. Our results showed that the indicator bacteria were detected at all stages of on-farm dairy processing. We observed a significant reduction in aerobic microbes and coliforms post-pasteurization. However, contamination of the final dairy products increased, suggesting potential cross-contamination during post-pasteurization. Metagenomic analysis revealed that Pseudomonas, a representative psychrotrophic bacterium, was predominant in both the farm (24.1 %) and pre-pasteurization (65.9 %) stages, indicating microbial transfer from the farms to the processing plants. Post-pasteurization, Pseudomonas and other psychrotrophs like Acinetobacter and Enterobacteriaceae remained dominant. Core microbiota analysis identified 74 genera in total, including 13 psychrotrophic bacteria, across all stages. Of the 59 strains isolated from these plants, 49 were psychrotrophic. Antimicrobial resistance analysis showed that 74.6 % (44/59) of isolates were resistant to at least one antibiotic, with cefoxitin-, ampicillin-, amoxicillin-, and ticarcillin-resistant bacteria present at all stages. Identical antimicrobial resistance patterns were observed in isolates from serial stages of the same farm and season, suggesting bacterial transmission across stages. Additionally, 27.1 % (16/59) of isolates carried plasmid-mediated resistance genes, which were also detected in the metagenomes of non-isolated samples, indicating potential antimicrobial resistance gene transmission and their presence in uncultured bacteria. These findings reveal the persistence of antimicrobial-resistant psychrotrophic bacteria in on-farm dairy processing plants, which pose potential health risks via dairy consumption. Our study underscores the importance of both culture-dependent and culture-independent methods to fully understand their distribution and impact.