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Bibliography on: Symbiosis

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ESP: PubMed Auto Bibliography 29 Jun 2022 at 01:50 Created: 

Symbiosis

Symbiosis refers to an interaction between two or more different organisms living in close physical association, typically to the advantage of both. Symbiotic relationships were once thought to be exceptional situations. Recent studies, however, have shown that every multicellular eukaryote exists in a tight symbiotic relationship with billions of microbes. The associated microbial ecosystems are referred to as microbiome and the combination of a multicellular organism and its microbiota has been described as a holobiont. It seems "we are all lichens now."

Created with PubMed® Query: symbiosis NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

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RevDate: 2022-06-28

Shin NR, Doucet D, Y Pauchet (2022)

Duplication of horizontally acquired GH5_2 enzymes played a central role in the evolution of longhorned beetles.

Molecular biology and evolution pii:6604784 [Epub ahead of print].

The rise of functional diversity through gene duplication contributed to the adaption of organisms to various environments. Here we investigate the evolution of putative cellulases of the subfamily 2 of glycoside hydrolase family 5 (GH5_2) in the Cerambycidae (longhorned beetles), a megadiverse assemblage of mostly xylophagous beetles. Cerambycidae originally acquired GH5_2 from a bacterial donor through horizontal gene transfer (HGT), and extant species harbor multiple copies that arose from gene duplication. We ask how these digestive enzymes contributed to the ability of these beetles to feed on wood. We analyzed 113 GH5_2, including the functional characterization of 52 of them, derived from 25 species covering most subfamilies of Cerambycidae. Ancestral gene duplications led to five well-defined groups with distinct substrate specificity, allowing these beetles to break down, in addition to cellulose, polysaccharides that are abundant in plant cell walls (PCWs), namely, xyloglucan, xylan, and mannans. Resurrecting the ancestral enzyme originally acquired by HGT, we show it was a cellulase that was able to break down glucomannan and xylan. Finally, recent gene duplications further expanded the catalytic repertoire of cerambycid GH5_2, giving rise to enzymes that favor transglycosylation over hydrolysis. We suggest that HGT and gene duplication, which shaped the evolution of GH5_2, played a central role in the ability of cerambycid beetles to use a PCW-rich diet and may have contributed to their successful radiation.

RevDate: 2022-06-28

Ruiz B, Sauviac L, Brouquisse R, et al (2022)

Role of Nitric Oxide (NO) of bacterial origin in the Medicago truncatula-Sinorhizobium meliloti symbiosis.

Molecular plant-microbe interactions : MPMI [Epub ahead of print].

Nitric oxide (NO) is a small ubiquitous gaseous molecule which has been found in many host-pathogen interactions. NO has been evidenced as part of the defense arsenal of animal cells and more recently of plant cells. To fight this molecular weapon, pathogens have evolved responses consisting in adaptation to NO or degradation of this toxic molecule. More recently, it was shown that NO could also be produced by the pathogen and contributes likewise to the success of the host cell infection. NO is also present during symbiotic interactions. Despite the growing knowledge about the role of NO during friendly interactions, data on the specificity of action of NO produced by each partner are scarce, partly due to the multiplicity of NO production systems. In the nitrogen fixing symbiosis between the soil bacterium Sinorhizobium meliloti and the model legume Medicago truncatula, NO has been detected at all steps of the interaction where it displays various roles. Both partners contribute to NO production inside the legume root nodules where nitrogen fixation occurs. The study focuses on the role of bacterial NO in this interaction. We used a genetic approach to identify bacterial NO sources in the symbiotic context and test the phenotype in planta of bacterial mutants affected in NO production. Our results show that only denitrification is a source of bacterial NO in Medicago nodules and give an insight on the role of bacteria-derived NO at different steps of the symbiotic interaction.

RevDate: 2022-06-28

Wei F, Liu Y, Zhou D, et al (2022)

Transcriptomic identification of a unique set of NCR peptides expressed in the nitrogen-fixing root nodule of Astragalus sinicus.

Molecular plant-microbe interactions : MPMI [Epub ahead of print].

Legumes in the inverted repeat-lacking clade (IRLC) each produce a unique set of nodule-specific cysteine-rich (NCR) peptides, which act in concert to determine the terminal differentiation of nitrogen-fixing bacteroid. IRLC legumes differ greatly in NCR number and sequence diversity. This raises a significant question how bacteroid differentiation is collectively controlled by the specific NCR repertoire of an IRLC legume. Astragalus sinicus is an IRLC legume that forms indeterminate nodules with its microsymbiont Mesorhizobium huakuii 7653R. Here, we performed transcriptome analysis of root and nodule samples at 3, 7, 14, 28 days post inoculation with M. huakuii 7653R and its isogenic ∆bacA mutant. BacA is a broad-specificity peptide transporter required for the host-derived NCRs to target rhizobial cells. A total of 167 NCRs were identified in the RNA transcripts. Comparative sequence and electrochemical analysis revealed that A. sinicus NCRs (AsNCRs) are dominated by a unique cationic group (termed subgroup C), whose mature portion is relatively long (>60 amino acids) and phylogenetically distinct and possessing six highly conserved cysteine residues. Subsequent functional characterization showed that a 7653R variant harboring AsNCR03 (a representative of subgroup C AsNCR) displayed significant growth inhibition in laboratory media, and formed ineffective white nodules on A. sinicus with irregular symbiosomes. Finally, bacterial two-hybrid analysis led to the identification of GroEL1 and GroEL3 as the molecular targets of AsNCR067 and AsNCR076. Together, our data contribute to a systematic understanding of the NCR repertoire associated with the A. sinicus and M. huakuii symbiosis.

RevDate: 2022-06-27

Liu Y, Yang M, Tang L, et al (2022)

TLR4 regulates RORγt+ regulatory T-cell responses and susceptibility to colon inflammation through interaction with Akkermansia muciniphila.

Microbiome, 10(1):98.

BACKGROUND: Well-balanced interactions between gut microbiota and the immune system are essential to prevent chronic intestinal inflammation, as observed in inflammatory bowel diseases (IBD). Toll-like receptor 4 (TLR4) functions as a sensor mediating the crosstalk between the intestinal commensal microbiome and host immunity, but the influence of TLR4 on the shaping of intestinal microbiota and immune responses during colon inflammation remains poorly characterized. We investigated whether the different susceptibilities to colitis between wild-type (WT) and TLR4-/- mice were gut microbiota-dependent and aimed to identify the potential immunity modulation mechanism.

METHODS: We performed antibiotic depletion of the microbiota, cohousing experiments, and faecal microbiota transplantation (FMT) in WT and TLR4-/- mice to assess the influence of TLR4 on intestinal microbial ecology. 16S rRNA sequencing was performed to dissect microbial discrepancies, and dysbiosis-associated immune perturbation was investigated by flow cytometry. Akkermansia muciniphila (A. muciniphila)-mediated immune modulation was confirmed through the T-cell transfer colitis model and bone marrow chimaera construction.

RESULTS: TLR4-/- mice experienced enhanced susceptibility to DSS-induced colitis. 16S rRNA sequencing showed notable discrepancy in the gut microbiota between WT and TLR4-/- mice. In particular, A. muciniphila contributed most to distinguishing the two groups. The T-cell transfer colitis model and bone marrow transplantation (BMT) consistently demonstrated that A. muciniphila ameliorated colitis by upregulating RORγt+ Treg cell-mediated immune responses. Mucosal biopsies from human manifested parallel outcomes with colon tissue from WT mice, as evidenced by the positive correlation between TLR4 expression and intestinal A. muciniphila colonization during homeostasis.

CONCLUSIONS: Our results demonstrate a novel protective role of TLR4 against intestinal inflammation, wherein it can modulate A. muciniphila-associated immune responses. These findings provide a new perspective on host-commensal symbiosis, which may be beneficial for developing potential therapeutic strategies. Video abstract.

RevDate: 2022-06-28
CmpDate: 2022-06-28

Suetsugu K, J Matsubayashi (2022)

Foliar chlorophyll concentration modulates the degree of fungal exploitation in a rhizoctonia-associated orchid.

Journal of experimental botany, 73(12):4204-4213.

Some green orchids obtain carbon from both mycobionts and photosynthesis at the adult stage. Intriguingly, these orchids can produce albino and, in rare cases, variegated phenotypes. Here, we studied a Platanthera hondoensis population with green, variegated, and albino individuals. Although its closely related Platanthera species are usually associated with non-ectomycorrhizal rhizoctonias, and several studies have failed to find evidence of trophic plasticity in rhizoctonia-associated orchids, variegated and albino P. hondoensis must possess a higher fungal dependency than green P. hondoensis. Therefore, we investigated whether (i) P. hondoensis is associated with non-ectomycorrhizal rhizoctonias and (ii) the degree of mycoheterotrophy (using 13C abundance as a proxy) correlates with the foliar chlorophyll concentration. High-throughput DNA sequencing revealed that all P. hondoensis phenotypes were dominantly associated with a rhizoctonia from Ceratobasidiaceae belonging to a clade distinct from recognized ectomycorrhizal clades. Regression analysis revealed a positive linear relationship between foliar chlorophyll concentration and the degree of mycoheterotrophy. This study strongly suggests that rhizoctonia-associated P. hondoensis can dynamically adjust fungal exploitation in response to photosynthetic carbon levels. Since rhizoctonia is the most common orchid mycorrhizal partner, trophic plasticity may be a widespread adaptive trait in green orchids.

RevDate: 2022-06-27

Kafle A, Cooney DR, Shah G, et al (2022)

Mycorrhiza-mediated potassium transport in Medicago truncatula can be evaluated by using rubidium as a proxy.

Plant science : an international journal of experimental plant biology pii:S0168-9452(22)00188-1 [Epub ahead of print].

Arbuscular mycorrhizal (AM) fungi considerably improve plant nutrient acquisition, particularly phosphorus and nitrogen. Despite the physiological importance of potassium (K+) in plants, there is increasing interest in the mycorrhizal contribution to plant K+ nutrition. Yet, methods to track K+ transport are often costly and limiting evaluation opportunities. Rubidium (Rb+) is known to be transported through same pathways as K+. As such our research efforts attempt to evaluate if Rb+ could serve as a viable proxy for evaluating K+ transport in AM symbiosis. Therefore, we examined the transport of K+ in Medicago truncatula colonized by the AM fungus Rhizophagus irregularis isolate 09 having access to various concentrations of Rb+ in custom-made two-compartment systems. Plant biomass, fungal root colonization, and shoot nutrient concentrations were recorded under sufficient and limited K+ regimes. We report that AM plants displayed higher shoot Rb+ and K+ concentrations and a greater K+:Na+ ratio relative to non-colonized plants in both sufficient and limited K+ conditions. Consequently, our results indicate that Rb+ can be used as a proxy to assess the movement of K+ in AM symbiosis, and suggest the existence of a mycorrhizal uptake pathway for K+ nutrition in M. truncatula.

RevDate: 2022-06-27

Mason CJ, Peiffer M, Chen B, et al (2022)

Opposing Growth Responses of Lepidopteran Larvae to the Establishment of Gut Microbiota.

Microbiology spectrum [Epub ahead of print].

Gut microbiota can have diverse impacts on hosts, the nature of which often depend on the circumstances. For insect gut microbes, the quality and nature of host diets can be a significant force in swinging the pendulum from inconsequential to functionally important. In our study, we addressed whether beneficial microbes in one species impart similar functions to related species under identical conditions. Using fall armyworm (Spodoptera frugiperda), beet armyworm (Spodoptera exigua), and other noctuid hosts, we implemented an axenic rearing strategy and manipulated gut bacterial populations and dietary conditions. Our results revealed that some gut Enterococcus and Enterobacter isolates can facilitate utilization of a poor diet substrate by fall armyworm, but this was not the case for other more optimized diets. While Enterococcus provided benefits to fall armyworm, it was decidedly antagonistic to beet armyworm (Spodoptera exigua) under identical conditions. Unique isolates and bacterial introductions at early growth stages were critical to how both larval hosts performed. Our results provide robust evidence of the roles in which bacteria support lepidopteran larval growth, but also indicate that the directionality of these relationships can differ among congener hosts. IMPORTANCE Insects have intimate relationships with gut microbiota, where bacteria can contribute important functions to their invertebrate hosts. Lepidopterans are important insect pests, but how they engage with their gut bacteria and how that translates to impacts on the host are lacking. Here we demonstrate the facultative nature of gut microbiota in lepidopteran larvae and the importance of diet in driving mutualistic or antagonistic relationships. Using multiple lepidopteran species, we uncover that the same bacteria that can facilitate exploitation of a challenging diet in one host severely diminishes larval performance of another larval species. Additionally, we demonstrate the beneficial functions of gut microbiota on the hosts are not limited to one lineage, but rather multiple isolates can facilitate the exploitation of a suboptimal diet. Our results illuminate the context-dependent nature of the gut microbiomes in invertebrates, and how host-specific microbial engagement can produce dramatically different interactions.

RevDate: 2022-06-27

Holley JC, Jackson MN, Pham AT, et al (2022)

Carpenter Bees (Xylocopa) Harbor a Distinctive Gut Microbiome Related to That of Honey Bees and Bumble Bees.

Applied and environmental microbiology [Epub ahead of print].

Eusocial corbiculate bees, including bumble bees and honey bees, maintain a socially transmitted core gut microbiome that contributes to digestion and pathogen defense. In contrast, solitary bees, which have fewer opportunities for direct interhost transmission, typically have less consistent microbiomes dominated by bacteria associated with pollen and food reserves. Carpenter bees (genus Xylocopa) are long-lived bees that are not eusocial but that often live in shared nesting sites. We characterized gut microbiomes for Xylocopa micans, X. mexicanorum, X. tabaniformis parkinsoniae, and X. virginica and for five solitary bee species from other genera (Andrena, Habropoda, Megachile, and Svastra), sampled in the same localities in central Texas. Unexpectedly, all four Xylocopa species had microbiomes dominated by bacterial lineages previously known only from social bees or other insect groups. Microbiomes were similar across three Xylocopa species and included lineages in the families Bifidobacteriaceae, Orbaceae, Lactobacillaceae, Pseudomonadaceae, and Enterobacteriaceae. In contrast, X. virginica had a distinct microbiome dominated by the genus Bombilactobacillus, a group abundant in guts of eusocial bees. Phylogenetic analyses support a past transfer of bacterial lineages into Xylocopa from bumble bees or honey bees. Gut microbiome compositions of Xylocopa species were distinct from those of other co-occurring solitary bees that had variable gut microbiomes dominated by bacteria from environmental sources. IMPORTANCE Gut microbiomes from social bees, such as honey bees and bumble bees, are conserved and consist of host-restricted bacteria that are transmitted among sterile female workers within a colony and that are important to the health of these key insect pollinators. In contrast, solitary bee species typically have more erratic, environmentally acquired microbiomes. Carpenter bees (genus Xylocopa) can be solitary as they lack a worker caste, and each female can excavate nests and raise offspring alone, although females are often social share nests at least in some species. This study showed that the gut microbiomes of four Xylocopa species have distinctive and consistent compositions and are dominated by bacterial lineages previously known from honey bees and bumble bees. Thus, eusociality is not required for bees to maintain a specialized, host-restricted gut microbiome. These findings suggest that gut bacteria are transmitted at shared nesting sites and that they play a role in host ecology.

RevDate: 2022-06-27

Heath KD, Batstone RT, Cerón Romero M, et al (2022)

MGEs as the MVPs of Partner Quality Variation in Legume-Rhizobium Symbiosis.

mBio [Epub ahead of print].

Despite decades of research, we are only just beginning to understand the forces maintaining variation in the nitrogen-fixing symbiosis between rhizobial bacteria and leguminous plants. In their recent work, Alexandra Weisberg and colleagues use genomics to document the breadth of mobile element diversity that carries the symbiosis genes of Bradyrhizobium in natural populations. Studying rhizobia from the perspective of their mobile genetic elements, which have their own transmission modes and fitness interests, reveals novel mechanisms for the generation and maintenance of diversity in natural populations of these ecologically and economically important mutualisms.

RevDate: 2022-06-27

Kumar H, N Kumar (2022)

Errors in antibiotic sensitivity testing: Barking up the wrong tree.

Annals of medicine and surgery (2012), 79:104015 pii:S2049-0801(22)00775-0.

RevDate: 2022-06-27

Lee MH, Medina Munoz M, RVM Rio (2022)

The Tsetse Metabolic Gambit: Living on Blood by Relying on Symbionts Demands Synchronization.

Frontiers in microbiology, 13:905826.

Tsetse flies have socioeconomic significance as the obligate vector of multiple Trypanosoma parasites, the causative agents of Human and Animal African Trypanosomiases. Like many animals subsisting on a limited diet, microbial symbiosis is key to supplementing nutrient deficiencies necessary for metabolic, reproductive, and immune functions. Extensive studies on the microbiota in parallel to tsetse biology have unraveled the many dependencies partners have for one another. But far less is known mechanistically on how products are swapped between partners and how these metabolic exchanges are regulated, especially to address changing physiological needs. More specifically, how do metabolites contributed by one partner get to the right place at the right time and in the right amounts to the other partner? Epigenetics is the study of molecules and mechanisms that regulate the inheritance, gene activity and expression of traits that are not due to DNA sequence alone. The roles that epigenetics provide as a mechanistic link between host phenotype, metabolism and microbiota (both in composition and activity) is relatively unknown and represents a frontier of exploration. Here, we take a closer look at blood feeding insects with emphasis on the tsetse fly, to specifically propose roles for microRNAs (miRNA) and DNA methylation, in maintaining insect-microbiota functional homeostasis. We provide empirical details to addressing these hypotheses and advancing these studies. Deciphering how microbiota and host activity are harmonized may foster multiple applications toward manipulating host health, including identifying novel targets for innovative vector control strategies to counter insidious pests such as tsetse.

RevDate: 2022-06-27

Chen J, Li J, Yang Y, et al (2022)

Effects of Conventional and Organic Agriculture on Soil Arbuscular Mycorrhizal Fungal Community in Low-Quality Farmland.

Frontiers in microbiology, 13:914627.

Arbuscular mycorrhizal (AM) fungi have promising applications in low-quality farmlands all over the world, but research on their responses to conventional and organic farming systems in low-quality soil is limited. We hypothesized that the colonization activity and community diversity of AM fungi in conventional farming systems may not be lower than in organic farming on low-quality farmlands where beneficial symbiosis is required. We collected soil and maize root samples from medium to low fertility farmlands with conventional or organic farming systems in western Jilin Province, China. The colonization percentage and intensity, taxonomic and phylogenetic diversity, community composition of soil AM fungi, and soil factors were detected and compared between the two farming systems. The colonization intensity and operational taxonomic unit (OTU) taxonomic diversity on conventional farms were higher than on organic farms. Glomus was the most common genus on conventional farms, whereas Paraglomus and Glomus were the most common on organic farms. We also found a simpler AM fungal network structure with lower OTU phylogenetic diversity on conventional farms. Our findings suggested that though the conventional farming system resulted in different compositions and simpler structures of soil AM fungal community, there are potential diverse OTU resources currently present on conventional farms. This work has potential impacts on understanding the influence of different farming systems on soil AM fungi in low-quality farmlands and the development of efficient mycorrhizal inoculant production.

RevDate: 2022-06-27

Fernández N, Knoblochová T, Kohout P, et al (2022)

Asymmetric Interaction Between Two Mycorrhizal Fungal Guilds and Consequences for the Establishment of Their Host Plants.

Frontiers in plant science, 13:873204.

Arbuscular mycorrhiza (AM) and ectomycorrhiza (EcM) are the most abundant and widespread types of mycorrhizal symbiosis, but there is little and sometimes conflicting information regarding the interaction between AM fungi (AMF) and EcM fungi (EcMF) in soils. Their competition for resources can be particularly relevant in successional ecosystems, which usually present a transition from AM-forming herbaceous vegetation to EcM-forming woody species. The aims of this study were to describe the interaction between mycorrhizal fungal communities associated with AM and EcM hosts naturally coexisting during primary succession on spoil banks and to evaluate how this interaction affects growth and mycorrhizal colonization of seedlings of both species. We conducted a greenhouse microcosm experiment with Betula pendula and Hieracium caespitosum as EcM and AM hosts, respectively. They were cultivated in three-compartment rhizoboxes. Two lateral compartments contained different combinations of both host plants as sources of fungal mycelia colonizing the middle compartment, where fungal biomass, diversity, and community composition as well as the growth of each host plant species' seedlings were analyzed. The study's main finding was an asymmetric outcome of the interaction between the two plant species: while H. caespitosum and associated AMF reduced the abundance of EcMF in soil, modified the composition of EcMF communities, and also tended to decrease growth and mycorrhizal colonization of B. pendula seedlings, the EcM host did not have such effects on AM plants and associated AMF. In the context of primary succession, these findings suggest that ruderal AM hosts could hinder the development of EcM tree seedlings, thus slowing the transition from AM-dominated to EcM-dominated vegetation in early successional stages.

RevDate: 2022-06-27

Lou H, Guo C, Fan B, et al (2022)

Lingonberry (Vaccinium vitis-idaea L.) Interact With Lachnum pygmaeum to Mitigate Drought and Promote Growth.

Frontiers in plant science, 13:920338.

The application of Ericoid mycorrhizal (ErM) fungi is considered to be an important strategy for increasing plant yield and drought resistance. In this study, we isolated and identified two ErM fungi that can promote the growth of lingonberry. We tried to understand the potential of these two ErM fungi to promote the growth of lingonberry and the strategies to help plants cope with water shortage. The use value of ErM fungi was evaluated by inoculating Oidiodendron maius FC (OmFC) or Lachnum pygmaeum ZL6 (LpZL6), well-watered (WW) and severe drought stress (SDS). The results showed that the mycelium of LpZL6 was denser than that of OmFC, and both ErM fungi significantly increased the biomass of lingonberry stems and roots. They also significantly increased the chlorophyll content by 65.6 and 97.8%, respectively. In addition, inoculation with LpZL6 fungi can improve drought resistance, promote root growth and increase root wet weight by 1157.6%. Drought reduced the chlorophyll content and soluble sugar content of lingonberry but increased significantly after inoculation with LpZL6. Inoculation with LpZL6 decreased lingonberry's malondialdehyde (MDA) content but increased the superoxide dismutase (SOD) activity. Overall, these results indicated that the successful coexistence of ErM fungi and lingonberry alleviated the adverse effects of drought stress through higher secondary metabolites and photosynthetic pigment synthesis.

RevDate: 2022-06-27
CmpDate: 2022-06-27

Huang M, Yuan M, Sun C, et al (2022)

Roles of AGD2a in Plant Development and Microbial Interactions of Lotus japonicus.

International journal of molecular sciences, 23(12): pii:ijms23126863.

Arabidopsis AGD2 (Aberrant Growth and Death2) and its close homolog ALD1 (AGD2-like defense response protein 1) have divergent roles in plant defense. We previously reported that modulation of salicylic acid (SA) contents by ALD1 affects numbers of nodules produced by Lotus japonicus, but AGD2's role in leguminous plants remains unclear. A combination of enzymatic analysis and biological characterization of genetic materials was used to study the function of AGD2 (LjAGD2a and LjAGD2b) in L. japonicus. Both LjAGD2a and LjAGD2b could complement dapD and dapE mutants of Escherichia coli and had aminotransferase activity in vitro. ljagd2 plants, with insertional mutations of LjAGD2, had delayed flowering times and reduced seed weights. In contrast, overexpression of LjAGD2a in L. japonicus induced early flowering, with increases in seed and flower sizes, but reductions in pollen fertility and seed setting rates. Additionally, ljagd2a mutation resulted in increased expression of nodulin genes and corresponding increases in infection threads and nodule numbers following inoculation with Rhizobium. Changes in expression of LjAGD2a in L. japonicus also affected endogenous SA contents and hence resistance to pathogens. Our results indicate that LjAGD2a functions as an LL-DAP aminotransferase and plays important roles in plant development. Moreover, LjAGD2a activates defense signaling via the Lys synthesis pathway, thereby participating in legume-microbe interaction.

RevDate: 2022-06-27
CmpDate: 2022-06-27

Li Y, Pei Y, Shen Y, et al (2022)

Progress in the Self-Regulation System in Legume Nodule Development-AON (Autoregulation of Nodulation).

International journal of molecular sciences, 23(12): pii:ijms23126676.

The formation and development of legumes nodules requires a lot of energy. Legumes must strictly control the number and activity of nodules to ensure efficient energy distribution. The AON system can limit the number of rhizobia infections and nodule numbers through the systemic signal pathway network that the aboveground and belowground parts participate in together. It can also promote the formation of nodules when plants are deficient in nitrogen. The currently known AON pathway includes four parts: soil NO3- signal and Rhizobium signal recognition and transmission, CLE-SUNN is the negative regulation pathway, CEP-CRA2 is the positive regulation pathway and the miR2111/TML module regulates nodule formation and development. In order to ensure the biological function of this important approach, plants use a variety of plant hormones, polypeptides, receptor kinases, transcription factors and miRNAs for signal transmission and transcriptional regulation. This review summarizes and discusses the research progress of the AON pathway in Legume nodule development.

RevDate: 2022-06-27
CmpDate: 2022-06-27

Wekesa C, Jalloh AA, Muoma JO, et al (2022)

Distribution, Characterization and the Commercialization of Elite Rhizobia Strains in Africa.

International journal of molecular sciences, 23(12): pii:ijms23126599.

Grain legumes play a significant role in smallholder farming systems in Africa because of their contribution to nutrition and income security and their role in fixing nitrogen. Biological Nitrogen Fixation (BNF) serves a critical role in improving soil fertility for legumes. Although much research has been conducted on rhizobia in nitrogen fixation and their contribution to soil fertility, much less is known about the distribution and diversity of the bacteria strains in different areas of the world and which of the strains achieve optimal benefits for the host plants under specific soil and environmental conditions. This paper reviews the distribution, characterization, and commercialization of elite rhizobia strains in Africa.

RevDate: 2022-06-27
CmpDate: 2022-06-27

Ngwenya ZD, Mohammed M, Jaiswal SK, et al (2022)

Phylogenetic relationships among Bradyrhizobium species nodulating groundnut (Arachis hypogea L.), jack bean (Canavalia ensiformis L.) and soybean (Glycine max Merr.) in Eswatini.

Scientific reports, 12(1):10629.

This study assessed the genetic diversity and phylogenetic relationships of rhizobial isolates obtained from root nodules of groundnut, jack bean and soybean planted in different locations within Eswatini. Seventy-six rhizobial isolates were studied using ERIC-PCR (enterobacterial repetitive intergenic consensus) fingerprinting and PCR amplification of 16S rRNA, housekeeping genes (atpD, dnaK, glnll and rpoB) and symbiotic genes (nifH and nodC). The dendrogram generated from the ERIC-PCR banding patterns grouped the test rhizobial isolates into 16 major clusters (Cluster I-XVI), with three isolates, namely TUTAHeS60, TUTGMeS3 and TUTAHeS127, forming outgroups of Clusters IV, VI and IX, respectively. Furthermore, the 76 test isolates were grouped into 56 ERIC-PCR types at 70% similarity level. The phylogenetic analysis of the 16S rRNA gene and multilocus sequence analysis of four housekeeping (atpD, dnaK, glnII and rpoB) and two symbiotic (nifH and nodC) genes showed that all three legumes (groundnut, jack bean and soybean) were nodulated by bacterial symbionts belonging to the genus Bradyrhizobium, with some isolates exhibiting high divergence from the known reference type strains. The results also showed that B. arachidis, B. iriomotense and B. canariense were the closest type strains to the groundnut isolates, while B. pachyrhizi and B. elkanii were the closest relatives to the bacterial symbionts associated with the nodulation of both jack bean and soybean. This study is the first report to describe of the bacterial symbionts nodulating jack bean in African soils.

RevDate: 2022-06-27
CmpDate: 2022-06-27

Fiege JK, RA Langlois (2022)

Embracing the heterogeneity of natural viruses in mouse studies.

The Journal of general virology, 103(6):.

Animal models are a critical tool in modern biology. To increase reproducibility and to reduce confounding variables modern animal models exclude many microbes, including key natural commensals and pathogens. Here we discuss recent strategies to incorporate a natural microbiota to laboratory mouse models and the impacts the microbiota has on immune responses, with a focus on viruses.

RevDate: 2022-06-27
CmpDate: 2022-06-23

Hu ZI, Link VM, Lima-Junior DS, et al (2022)

Immune checkpoint inhibitors unleash pathogenic immune responses against the microbiota.

Proceedings of the National Academy of Sciences of the United States of America, 119(26):e2200348119.

Immune checkpoint inhibitors (ICIs) are essential components of the cancer therapeutic armamentarium. While ICIs have demonstrated remarkable clinical responses, they can be accompanied by immune-related adverse events (irAEs). These inflammatory side effects are of unclear etiology and impact virtually all organ systems, with the most common being sites colonized by the microbiota such as the skin and gastrointestinal tract. Here, we establish a mouse model of commensal bacteria-driven skin irAEs and demonstrate that immune checkpoint inhibition unleashes commensal-specific inflammatory T cell responses. These aberrant responses were dependent on production of IL-17 by commensal-specific T cells and induced pathology that recapitulated the cutaneous inflammation seen in patients treated with ICIs. Importantly, aberrant T cell responses unleashed by ICIs were sufficient to perpetuate inflammatory memory responses to the microbiota months following the cessation of treatment. Altogether, we have established a mouse model of skin irAEs and reveal that ICIs unleash aberrant immune responses against skin commensals, with long-lasting inflammatory consequences.

RevDate: 2022-06-25

Wang X, Chen K, Zhou M, et al (2022)

GmNAC181 promotes symbiotic nodulation and salt tolerance of nodulation by directly regulating GmNINa expression in soybean.

The New phytologist [Epub ahead of print].

Soybean (Glycine max) is one of the most important crops worldwide. Under low nitrogen condition, soybean can form a symbiotic relationship with rhizobia to acquire sufficient nitrogen for their growth and production. Nodulation signaling controls soybean symbiosis with rhizobia. The soybean Nodule Inception (GmNINa) gene is a central regulator of soybean nodulation. However, the transcriptional regulation of GmNINa remains largely unknown. Nodulation is sensitive to salt stress, but the underlying mechanisms are unclear. Here, we identified a NAC transcription factor designated GmNAC181 (also known as GmNAC11) as the interacting protein of GmNSP1a. GmNAC181 overexpression or knockdown resulted in increased or decreased numbers of nodules, respectively, in soybean. Accordingly, the expression of GmNINa was greatly up- and downregulated, respectively. Furthermore, we showed that GmNAC181 can directly bind to the GmNINa promoter to activate its gene expression. Intriguingly, GmNAC181 was highly induced by salt stress during nodulation and promoted symbiotic nodulation under salt stress. We identified a new transcriptional activator of GmNINa in the nodulation pathway and revealed a mechanism by which GmNAC181 acts as a network node orchestrating the expression of GmNINa and symbiotic nodulation under salt stress conditions.

RevDate: 2022-06-24

Song H, Kim KT, Park SY, et al (2022)

A comparative genomic analysis of lichen-forming fungi reveals new insights into fungal lifestyles.

Scientific reports, 12(1):10724.

Lichen-forming fungi are mutualistic symbionts of green algae or cyanobacteria. We report the comparative analysis of six genomes of lichen-forming fungi in classes Eurotiomycetes and Lecanoromycetes to identify genomic information related to their symbiotic lifestyle. The lichen-forming fungi exhibited genome reduction via the loss of dispensable genes encoding plant-cell-wall-degrading enzymes, sugar transporters, and transcription factors. The loss of these genes reflects the symbiotic biology of lichens, such as the absence of pectin in the algal cell wall and obtaining specific sugars from photosynthetic partners. The lichens also gained many lineage- and species-specific genes, including those encoding small secreted proteins. These genes are primarily induced during the early stage of lichen symbiosis, indicating their significant roles in the establishment of lichen symbiosis.Our findings provide comprehensive genomic information for six lichen-forming fungi and novel insights into lichen biology and the evolution of symbiosis.

RevDate: 2022-06-24

Yang YM, Naseer M, Zhu Y, et al (2022)

Dual effects of nZVI on maize growth and water use are positively mediated by arbuscular mycorrhizal fungi via rhizosphere interactions.

Environmental pollution (Barking, Essex : 1987) pii:S0269-7491(22)00875-2 [Epub ahead of print].

Nanoscale zero-valent iron (nZVI) might generate positive and negative effects on plant growth, since it acts as either hazardous or growth-promotion role. It is still unclear whether such dual roles can be mediated by arbuscular mycorrhizal fungifungi (AMF) in plant-AMF symbiosis. We first identified that in 1.5 g kg-1 nZVI (≤1.5 g kg-1 positively), maize biomass was increased by 15.83%; yet in 2.0 g kg-1 nZVI, it turned to be declined by 6.83%, relative to non-nZVI condition (CK, p < 0.05), showing a negative effect. Interestingly, the inoculation of AMF massively improved biomass by 45.18% in 1.5 g kg-1 nZVI, and relieved the growth inhibition by 2.0 g kg-1 nZVI. The event of water use efficiency followed similar trend as that of biomass. We found that proper concentration of nZVI can positively interact with rhizosphere AMF carrier, enabling more plant photosynthetic carbon to be remobilized to mycorrhiza. The scanning of transmission electron microscopy showed that excessive nZVI can infiltrate into root cortical cells and disrupt cellular homeostasis mechanism, significantly increasing iron content in roots by 76.01% (p < 0.05). Simultaneously, the images of scanning electron microscopy showed that nZVI were attached on root surface to form an insoluble iron ion (Fe3+) layer, hindering water absorption. However, they were efficiently immobilized and in situ intercepted by extraradical hyphae in mycorrhizal-nZVI symbiosis, lowering iron translocation efficiency by 6.07% (p < 0.05). Herein, the optimized structure remarkably diminished aperture blockage at root surface and improved root activities by 30.06% (p < 0.05). Particularly, next-generation sequencing demonstrated that appropriate amount of nZVI promoted the colonization and development of Funneliformis mosseae as dominant species in rhizosphere, confirming the positive interaction between AMF and nZVI, and its regulatory mechanism. Therefore, dual effects of nZVI can be actively mediated by AMF via rhizosphere interactions. The findings provided new insights into the safe and efficient application of nanomaterials in agriculture.

RevDate: 2022-06-24

Prescott SL, Logan AC, Bristow J, et al (2022)

Exiting the Anthropocene: Achieving Personal and Planetary Health in the 21st Century.

Allergy [Epub ahead of print].

Planetary health provides a perspective of ecological interdependence that connects the health and vitality of individuals, communities, and Earth's natural systems. It includes the social, political, and economic ecosystems that influence both individuals and whole societies. In an era of interconnected grand challenges threatening health of all systems at all scales, planetary health provides a framework for cross-sectoral collaboration and unified systems approaches to solutions. The field of allergy is at the forefront of these efforts. Allergic conditions are a sentinel measure of environmental impact on human health in early life-illuminating how ecological changes affect immune development and predispose to a wider range of inflammatory noncommunicable diseases (NCDs). This shows how adverse macroscale ecology in the Anthropocene penetrates to the molecular level of personal and microscale ecology, including the microbial systems at the foundations of all ecosystems. It provides the basis for more integrated efforts to address widespread environmental degradation and adverse effects of maladaptive urbanisation, food systems, lifestyle behaviours, and socioeconomic disadvantage. Nature-based solutions and efforts to improve nature-relatedness are crucial for restoring symbiosis, balance, and mutualism in every sense, recognizing that both personal lifestyle choices and collective structural actions are needed in tandem. Ultimately, meaningful ecological approaches will depend on placing greater emphasis on psychological and cultural dimensions such as mindfulness, values, and moral wisdom to ensure a sustainable and resilient future.

RevDate: 2022-06-24

Ndabankulu K, Tsvuura Z, A Magadlela (2022)

Alien invasive Leucaena leucocephala successfully acquires nutrients by investing in below-ground biomass compared to native Vachellia nilotica in nutrient-amended soils in South Africa.

AoB PLANTS, 14(3):plac026 pii:plac026.

Soils in grasslands and savannas of southern Africa are acidic and nutrient-poor. Legume plants, such as Vachellia nilotica and alien invasive Leucaena leucocephala, are a major component of the vegetation there. Vachellia nilotica can establish in drought-prone environments, and is invasive in high rainfall areas. Leucaena leucocephala is an emerging invasive in South Africa and is ranked among the world's 100 most invasive alien species. Alien plants can invade native habitats through their adaptability to low-resource soils, and thus can out-compete and displace native vegetation. We investigated the effects of phosphorus (P) deficiency and soil acidity on legume-microbe symbiosis, nitrogen (N) nutrition and carbon (C) growth costs of these two legumes in grassland soils. We used as inoculum and growth substrate soils collected from a long-term (>65 years) nutrient and lime-addition trial, the Veld Fertilizer Trial (VFT), located at Ukulinga Research Farm near Pietermaritzburg in South Africa. We used soils from three VFT treatments: soils fertilized with superphosphate (336 kg ha-1) applied once per year (+P), soils fertilized with superphosphate (336 kg ha-1) applied once per year with dolomitic lime (2250 kg ha-1) applied once every 5 years (P+L) and soils with no superphosphate and no dolomitic lime applications (Control). Seeds of V. nilotica and L. leucocephala were germinated and grown independently in these soils in green house conditions and harvested after 125 days for measurement of growth, legume-microbe symbiosis, N nutrition and C growth costs. Results showed that the two legumes had different growth adaptations. Vachellia nilotica grown in control soils and +P soils nodulated with various Burkholderia spp., while L. leucocephala did not nodulate in all soil treatments. Both legumes utilized for growth both atmospheric- and soil-derived N across all treatments thereby decreasing C growth costs. Vachellia nilotica grown in +P soils accumulated the most biomass and N nutrition. Leucaena leucocephala maximized specific N assimilation rates by investing in below-ground biomass accumulation in control soils. This shows that L. leucocephala possesses traits that are successful in acquiring nutrients by investing in below-ground biomass and relying on utilization of N from both the soil and the atmosphere.

RevDate: 2022-06-24

Engelenburg HJ, Lucassen PJ, Sarafian JT, et al (2022)

Multiple sclerosis and the microbiota: Progress in understanding the contribution of the gut microbiome to disease.

Evolution, medicine, and public health, 10(1):277-294 pii:eoac009.

Multiple sclerosis (MS), a neurological autoimmune disorder, has recently been linked to neuro-inflammatory influences from the gut. In this review, we address the idea that evolutionary mismatches could affect the pathogenesis of MS via the gut microbiota. The evolution of symbiosis as well as the recent introduction of evolutionary mismatches is considered, and evidence regarding the impact of diet on the MS-associated microbiota is evaluated. Distinctive microbial community compositions associated with the gut microbiota of MS patients are difficult to identify, and substantial study-to-study variation and even larger variations between individual profiles of MS patients are observed. Furthermore, although some dietary changes impact the progression of MS, MS-associated features of microbiota were found to be not necessarily associated with diet per se. In addition, immune function in MS patients potentially drives changes in microbial composition directly, in at least some individuals. Finally, assessment of evolutionary histories of animals with their gut symbionts suggests that the impact of evolutionary mismatch on the microbiota is less concerning than mismatches affecting helminths and protists. These observations suggest that the benefits of an anti-inflammatory diet for patients with MS may not be mediated by the microbiota per se. Furthermore, any alteration of the microbiota found in association with MS may be an effect rather than a cause. This conclusion is consistent with other studies indicating that a loss of complex eukaryotic symbionts, including helminths and protists, is a pivotal evolutionary mismatch that potentiates the increased prevalence of autoimmunity within a population.

RevDate: 2022-06-24

Dabré ÉE, Hijri M, C Favret (2022)

Influence on Soybean Aphid by the Tripartite Interaction between Soybean, a Rhizobium Bacterium, and an Arbuscular Mycorrhizal Fungus.

Microorganisms, 10(6): pii:microorganisms10061196.

The inoculation of arbuscular mycorrhizal (AM) fungi and rhizobia in legumes has been proven to increase plant growth and yield. To date, studies of the effects of these interactions on phytophagous insects have shown them to be context-dependent depending on the inoculant strain, the plant, and the insect species. Here, we document how a symbiosis involving an AM fungus, Rhizophagus irregularis; a rhizobium, Bradyrhizobium japonicum; and soybean, Glycine max, influences the soybean aphid, Aphis glycines. Soybean co-inoculated with the AM fungus-rhizobium pair increased the plant's biomass, nodulation, mycorrhizal colonization, nitrogen, and carbon concentrations, but decreased phosphorus concentration. Similar effects were observed with rhizobium alone, with the exception that root biomass was unaffected. With AM fungus alone, we only observed an increase in mycorrhizal colonization and phosphorus concentration. The aphids experienced an increased reproductive rate with the double inoculation, followed by rhizobium alone, whereas no effect was observed with the AM fungus. The size of individual aphids was not affected. Furthermore, we found positive correlation between nitrogen concentration and aphid population density. Our results confirm that co-inoculation of two symbionts can enhance both plant and phytophagous insect performance beyond what either symbiont can contribute alone.

RevDate: 2022-06-24

Dabré ÉE, Brodeur J, Hijri M, et al (2022)

The Effects of an Arbuscular Mycorrhizal Fungus and Rhizobium Symbioses on Soybean Aphid Mostly Fail to Propagate to the Third Trophic Level.

Microorganisms, 10(6): pii:microorganisms10061158.

The cascading effects of microbe-plant symbioses on the second trophic level, such as phytophagous insects, have been most studied. However, few studies have examined the higher third trophic level, i.e., their natural enemies. We investigated the effects of the symbiotic associations between an arbuscular mycorrhizal (AM) fungus, Rhizophagus irregularis (Glomerales: Glomeraceae), a nitrogen-fixing bacterium, Bradyrhizobium japonicum (Rhizobiales: Bradyrhizobiaceae), and soybean, Glycine max (L.) Merr. (Fabaceae) on two natural enemies of the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), the ladybird beetle Coleomegilla maculata (De Geer) (Coleoptera: Coccinellidae), and the parasitoid Aphelinus certus Yasnosh (Hymenoptera: Aphelinidae). We measured the growth and survival in the predator and parasitoid reared on aphids feeding on soybean inoculated seedlings. The rhizobium symbiosis alone was affected with a decreased rate of parasitoid emergence, presumably due to decreased host quality. However, number of mummies, sex-ratio, development time, and parasitoid size were all unaffected by inoculation. AM fungus alone or co-inoculated with the rhizobium was unaffected with any of the parameters of the parasitoid. For the predator, none of the measured parameters was affected with any inoculant. Here, it appears that whatever benefits the microbe-plant symbioses confer on the second trophic level are little transferred up to the third.

RevDate: 2022-06-24

Shinde DB, Koratkar SS, Rale V, et al (2022)

Effect of Encapsulated Ferrous Sulphate Fortified Salt on Hemoglobin Levels in Anemic Rats.

Foods (Basel, Switzerland), 11(12): pii:foods11121795.

(1) Background: Iron deficiency anemia is a significant nutritional problem all over the world. Salt formulations supplemented with encapsulated iron and iodine (double-fortified) were tested for their efficacy in managing iron deficiency anemia. In this study, we have checked the effect of these double-fortified salt formulations (iron and iodine) on hemoglobin (Hb) levels in anemic Wistar male rats. (2) Methods: The study was divided into two phases, viz., the development of anemia in the first phase and then the random division of anemic rats into five groups (Groups A to E). These rats were fed with three different salt formulations (Groups A to C); Group D was continued on a low iron diet, and Group E was on a normal pellet diet over a period of 84 days. The level of Hb was tested in each group. (3) Results: The rats in Groups A, B, C, and E recovered from anemia significantly, with higher Hb levels. On day 84, however, the Hb level in Group D continued to decrease. The bodyweight of the rats was not affected in any way. In all of the groups, histopathology examinations in various organs revealed no significant changes. (4) Conclusions: All of the three different salt formulations showed significant recovery in the anemic rats as compared to the rats fed with a normal pelleted diet.

RevDate: 2022-06-24

Benjamin G, Pandharikar G, P Frendo (2022)

Salicylic Acid in Plant Symbioses: Beyond Plant Pathogen Interactions.

Biology, 11(6): pii:biology11060861.

Plants form beneficial symbioses with a wide variety of microorganisms. Among these, endophytes, arbuscular mycorrhizal fungi (AMF), and nitrogen-fixing rhizobia are some of the most studied and well understood symbiotic interactions. These symbiotic microorganisms promote plant nutrition and growth. In exchange, they receive the carbon and metabolites necessary for their development and multiplication. In addition to their role in plant growth and development, these microorganisms enhance host plant tolerance to a wide range of environmental stress. Multiple studies have shown that these microorganisms modulate the phytohormone metabolism in the host plant. Among the phytohormones involved in the plant defense response against biotic environment, salicylic acid (SA) plays an important role in activating plant defense. However, in addition to being a major actor in plant defense signaling against pathogens, SA has also been shown to be involved in plant-microbe symbiotic interactions. In this review, we summarize the impact of SA on the symbiotic interactions. In addition, we give an overview of the impact of the endophytes, AMF, and rhizobacteria on SA-mediated defense response against pathogens.

RevDate: 2022-06-24

Mendoza-Soto AB, Rodríguez-Corral AZ, Bojórquez-López A, et al (2022)

Arbuscular Mycorrhizal Symbiosis Leads to Differential Regulation of Genes and miRNAs Associated with the Cell Wall in Tomato Leaves.

Biology, 11(6): pii:biology11060854.

Arbuscular mycorrhizal symbiosis is an association that provides nutritional benefits to plants. Importantly, it induces a physiological state allowing plants to respond to a subsequent pathogen attack in a more rapid and intense manner. Consequently, mycorrhiza-colonized plants become less susceptible to root and shoot pathogens. This study aimed to identify some of the molecular players and potential mechanisms related to the onset of defense priming by mycorrhiza colonization, as well as miRNAs that may act as regulators of priming genes. The upregulation of cellulose synthases, pectinesterase inhibitors, and xyloglucan endotransglucosylase/hydrolase, as well as the downregulation of a pectinesterase, suggest that the modification and reinforcement of the cell wall may prime the leaves of mycorrhizal plants to react faster and stronger to subsequent pathogen attack. This was confirmed by the findings of miR164a-3p, miR164a-5p, miR171e-5p, and miR397, which target genes and are also related to the biosynthesis or modification of cell wall components. Our findings support the hypothesis that the reinforcement or remodeling of the cell wall and cuticle could participate in the priming mechanism triggered by mycorrhiza colonization, by strengthening the first physical barriers upstream of the pathogen encounter.

RevDate: 2022-06-24

Margarita V, Cao LC, Bailey NP, et al (2022)

Effect of the Symbiosis with Mycoplasma hominis and Candidatus Mycoplasma Girerdii on Trichomonas vaginalis Metronidazole Susceptibility.

Antibiotics (Basel, Switzerland), 11(6): pii:antibiotics11060812.

Trichomoniasis, the most common non-viral sexually transmitted infection worldwide, is caused by the protozoon Trichomonas vaginalis. The 5- nitroimidazole drugs, of which metronidazole is the most prescribed, are the only effective drugs to treat trichomoniasis. Resistance against metronidazole is increasingly reported among T. vaginalis isolates. T. vaginalis can establish an endosymbiosis with two Mycoplasma species, Mycoplasma hominis and Candidatus Mycoplasma girerdii, whose presence has been demonstrated to influence several aspects of the protozoan pathobiology. The role of M. hominis in T. vaginalis resistance to metronidazole is controversial, while the influence of Ca. M. girerdii has never been investigated. In this work, we investigate the possible correlation between the presence of Ca. M. girerdii and/or M. hominis and the in vitro drug susceptibility in a large group of T. vaginalis isolated in Italy and in Vietnam. We also evaluated, via RNA-seq analysis, the expression of protozoan genes involved in metronidazole resistance in a set of syngenic T. vaginalis strains, differing only for the presence/absence of the two Mycoplasmas. Our results show that the presence of M. hominis significantly increases the sensitivity to metronidazole in T. vaginalis and affects gene expression. On the contrary, the symbiosis with Candidatus Mycoplasma girerdii seems to have no effect on metronidazole resistance in T. vaginalis.

RevDate: 2022-06-24
CmpDate: 2022-06-24

Sharp C, KR Foster (2022)

Host control and the evolution of cooperation in host microbiomes.

Nature communications, 13(1):3567.

Humans, and many other species, are host to diverse symbionts. It is often suggested that the mutual benefits of host-microbe relationships can alone explain cooperative evolution. Here, we evaluate this hypothesis with evolutionary modelling. Our model predicts that mutual benefits are insufficient to drive cooperation in systems like the human microbiome, because of competition between symbionts. However, cooperation can emerge if hosts can exert control over symbionts, so long as there are constraints that limit symbiont counter evolution. We test our model with genomic data of two bacterial traits monitored by animal immune systems. In both cases, bacteria have evolved as predicted under host control, tending to lose flagella and maintain butyrate production when host-associated. Moreover, an analysis of bacteria that retain flagella supports the evolution of host control, via toll-like receptor 5, which limits symbiont counter evolution. Our work puts host control mechanisms, including the immune system, at the centre of microbiome evolution.

RevDate: 2022-06-23

George EE, Tashyreva D, Kwong WK, et al (2022)

Gene Transfer Agents in Bacterial Endosymbionts of Microbial Eukaryotes.

Genome biology and evolution pii:6615375 [Epub ahead of print].

Gene transfer agents (GTAs) are virus-like structures that package and transfer prokaryotic DNA from donor to recipient prokaryotic cells. Here, we describe widespread GTA gene clusters in the highly reduced genomes of bacterial endosymbionts from microbial eukaryotes (protists). Homologs of the GTA capsid and portal complexes were initially found to be present in several highly reduced alphaproteobacterial endosymbionts of diplonemid protists (Rickettsiales and Rhodospirillales). Evidence of GTA expression was found in polyA-enriched metatranscriptomes of the diplonemid hosts and their endosymbionts, but due to biases in the polyA-enrichment methods, levels of GTA expression could not be determined. Examining the genomes of closely related bacteria revealed that the pattern of retained GTA head/capsid complexes with missing tail components was common across Rickettsiales and Holosporaceae (Rhodospirillales), all obligate symbionts with a wide variety of eukaryotic hosts. A dN/dS analysis of Rickettsiales and Holosporaceae symbionts revealed that purifying selection is likely the main driver of GTA evolution in symbionts, suggesting they remain functional, but the ecological function of GTAs in bacterial symbionts is unknown. In particular, it is unclear how increasing horizontal gene transfer in small, largely clonal endosymbiont populations can explain GTA retention, and therefore, the structures may have been repurposed in endosymbionts for host interactions. Either way, their widespread retention and conservation in endosymbionts of diverse eukaryotes suggests an important role in symbiosis.

RevDate: 2022-06-23

Bonfante P (2022)

Microbe Profile: Gigaspora margarita, a multifaceted arbuscular mycorrhizal fungus.

Microbiology (Reading, England), 168(6):.

Gigaspora margarita is a cosmopolitan arbuscular mycorrhizal fungus, which - as an obligate symbiont- requires being associated to a host plant to accomplish its life cycle. It is characterized by huge white spores, the development of extraradical auxiliary cells, and the lack of intraradical vesicles. Its genome is dominated by transposable elements and is one of the largest fungal genomes so far sequenced. G. margarita has the peculiar feature to host taxonomically different endobacteria in its cytoplasm. The development of a cured line has allowed us to demonstrate how the endobacteria have a positive impact on the fungal physiology and -with a cascade effect- on the mycorrhizal plant.

RevDate: 2022-06-23

Araújo JPM, Li Y, Duong TA, et al (2022)

Four New Species of Harringtonia: Unravelling the Laurel Wilt Fungal Genus.

Journal of fungi (Basel, Switzerland), 8(6): pii:jof8060613.

Symbiosis between beetles and fungi arose multiple times during the evolution of both organisms. Some of the most biologically diverse and economically important are mutualisms in which the beetles cultivate and feed on fungi. Among these are bark beetles and Harringtonia, a fungal genus that produces Raffaelea-like asexual morph and hosts the causal agent of laurel wilt, H. lauricola (formerly Raffaelea lauricola). In this study, we propose four new species of Harringtonia associated with beetles from Belize and Florida (USA). We hope to contribute towards a more robust and inclusive phylogenetic framework for future studies on these beetle-fungi relationships and their potential impact in crops and forests worldwide.

RevDate: 2022-06-23

Ilgun A, T Schmickl (2022)

Mycelial Beehives of HIVEOPOLIS: Designing and Building Therapeutic Inner Nest Environments for Honeybees.

Biomimetics (Basel, Switzerland), 7(2): pii:biomimetics7020075.

The perceptions and definitions of healthy indoor environments have changed significantly throughout architectural history. Today, molecular biology teaches us that microbes play important roles in human health, and that isolation from them puts not only us but also other inhabitants of urban landscapes, at risk. In order to provide an environment that makes honeybees more resilient to environmental changes, we aim for combining the thermal insulation functionality of mycelium materials with bioactive therapeutic properties within beehive constructions. By identifying mycelial fungi's interactions with nest-related materials, using digital methods to design a hive structure, and engaging in additive manufacturing, we were able to develop a set of methods for designing and fabricating a fully grown hive. We propose two digital methods for modelling 3D scaffolds for micro-super organism co-occupation scenarios: "variable-offset" and "iterative-subtraction", followed by two inoculation methods for the biofabrication of scaffolded fungal composites. The HIVEOPOLIS project aims to diversify and complexify urban ecological niches to make them more resilient to future game changers such as climate change. The combined functions of mycelium materials have the potential to provide a therapeutic environment for honeybees and, potentially, humans in the future.

RevDate: 2022-06-23

Angadi KM, Jadhav VB, SV Jadhav (2022)

Quality Assurance with Reference Quality Control Strains in Antimicrobial Susceptibility Testing: Need for Quality Antimicrobial-Resistant Research [Letter].

Infection and drug resistance, 15:3075-3076 pii:376887.

RevDate: 2022-06-23

Bathia J, Schröder K, Fraune S, et al (2022)

Symbiotic Algae of Hydra viridissima Play a Key Role in Maintaining Homeostatic Bacterial Colonization.

Frontiers in microbiology, 13:869666.

The freshwater polyp Hydra viridissima (H. viridissima) harbors endosymbiotic Chlorella algae in addition to a species-specific microbiome. The molecular basis of the symbiosis between Hydra and Chlorella has been characterized to be metabolic in nature. Here, we studied the interaction between the extracellularly located microbiota and the algal photobiont, which resides in Hydra's endodermal epithelium, with main focus on Legionella bacterium. We aimed at evaluating the influence of the symbiotic algae on microbial colonization and in shaping the host microbiome. We report that the microbiome composition of symbiotic and aposymbiotic (algae free) H. viridissima is significantly different and dominated by Legionella spp. Hvir in aposymbiotic animals. Co-cultivation of these animals resulted in horizontal transmission of Legionella spp. Hvir bacteria from aposymbiotic to symbiotic animals. Acquisition of this bacterium increased the release of algae into ambient water. From there, algae could subsequently be taken up again by the aposymbiotic animals. The presence of algal symbionts had negative impact on Legionella spp. Hvir and resulted in a decrease of the relative abundance of this bacterium. Prolonged co-cultivation ultimately resulted in the disappearance of the Legionella spp. Hvir bacterium from the Hydra tissue. Our observations suggest an important role of the photobiont in controlling an invasive species in a metacommunity and, thereby, shaping the microbiome.

RevDate: 2022-06-23

Ran Z, Ding W, Cao S, et al (2022)

Arbuscular mycorrhizal fungi: Effects on secondary metabolite accumulation of Traditional Chinese medicine.

Plant biology (Stuttgart, Germany) [Epub ahead of print].

Traditional Chinese medicine (TCM) has played a pivotal role in maintaining the health of people, and the intrinsic quality of TCM is directly related to the clinical efficacy. The medicinal ingredients of TCM are derived from the secondary metabolites of plant metabolism and are also the result of the coordination of various physiological activities in plants. Arbuscular mycorrhizal fungi (AMF) is among the most ubiquitous plant mutualists that enhance the growth and yield of plants by facilitating the uptake of nutrients and water. Symbiosis of AMF with higher plants promotes growth and helps in the accumulation of secondary metabolites in plants. However, there is still no systematic analysis and summarization of their roles in the application of TCM, biosynthesis, and accumulation of active substances of herbs as well as the mechanism. AMF directly or indirectly affects the accumulation of secondary metabolites of TCM, which is the focus of this review. First, in this review, the effects of AM symbiosis on the content of different secondary metabolites in TCM such as phenolic acids, flavonoids, alkaloids, and terpenoids are mainly summarized. Moreover, the mechanism of AMF regulating the synthesis of secondary metabolites was also considered in combination with the establishment of mycorrhizal symbionts, response mechanism of plant hormones, nutrition elements, and expression of key enzyme activities. Finally, combined with the current application prospect of AMF in TCM, the future in-depth research is planned, thus providing a reference for improving the quality of TCM. In this manuscript, we reviewed the research status of AMF in promoting the accumulation of secondary metabolites in TCM to provide new ideas and methods for improving the quality of TCM.

RevDate: 2022-06-23
CmpDate: 2022-06-23

Romero-Leiton JP, Prieto K, Reyes-Gonzalez D, et al (2022)

Optimal control and Bayes inference applied to complex microbial communities.

Mathematical biosciences and engineering : MBE, 19(7):6860-6882.

Interactions between species are essential in ecosystems, but sometimes competition dominates over mutualism. The transition between mutualism-competition can have several implications and consequences, and it has hardly been studied in experimental settings. This work studies the mutualism between cross-feeding bacteria in strains that supply an essential amino acid for their mutualistic partner when both strains are exposed to antimicrobials. When the strains are free of antimicrobials, we found that, depending on the amount of amino acids freely available in the environment, the strains can exhibit extinction, mutualism, or competition. The availability of resources modulates the behavior of both species. When the strains are exposed to antimicrobials, the population dynamics depend on the proportion of bacteria resistant to the antimicrobial, finding that the extinction of both strains is eminent for low levels of the resource. In contrast, competition between both strains continues for high levels of the resource. An optimal control problem was then formulated to reduce the proportion of resistant bacteria, which showed that under cooperation, both strains (sensitive and resistant) are immediately controlled, while under competition, only the density of one of the strains is decreased. In contrast, its mutualist partner with control is increased. Finally, using our experimental data, we did parameters estimation in order to fit our mathematical model to the experimental data.

RevDate: 2022-06-23
CmpDate: 2022-06-23

Chen Y, Zhang L, Zhang S, et al (2022)

The mite Acarus farris inducing defensive behaviors and reducing fitness of termite Coptotermes formosanus: implications for phoresy as a precursor to parasitism.

BMC ecology and evolution, 22(1):80.

BACKGROUND: The ecology and evolution of phoretic mites and termites have not been well studied. In particular, it is unknown whether the specific relationship between mites and termites is commensal or parasitic. High phoretic mite densities have often been found to occur in weak termite colonies, suggesting that the relationship is closer to that of parasitism than commensalism.

RESULTS: To examine this, Coptotermes formosanus was used as a carrier, and Acarus farris as the phoretic mite. We used video recordings to observe termite social immunity behaviors and bioassay to examine termite fitness. Our results showed that the attachment of the mite on the termite can enhance termite social immunity behaviors like alarm vibration and grooming frequency while decreasing the duration of individual grooming episodes in phoretic mites. Further, A. farris phoresy led to a 22.91% reduction in termite abdomen volume and a 3.31-fold increase in termite mortality.

CONCLUSIONS: When termites groom more frequently, the consequence is short duration of grooming bouts. This may be indicative of a trade-off which provides suggestive evidence that frequent social behaviors may cost termites energy. And this caused phoretic behavior hastened termites' death, and helped propagate the population of mites feeding on dead termites. So, it provides a case for phoresy being a precursor to parasitism, and the specific relationship between A. farris and C. formosanus is closer to parasitism than to commensalism.

RevDate: 2022-06-23
CmpDate: 2022-06-23

Leung TLF (2022)

Economies of parasite body size.

Current biology : CB, 32(12):R645-R649.

Parasitism has independently evolved multiple times across the entire tree of life, and there are numerous parasitic representatives from every major eukaryote kingdom. In animals alone, parasitism has independently evolved at least 200 times. If there are any organisms that one might think would have access to limitless resources, it would be parasites. You would think that living in or on the body of their host, which serves as both a habitat and a food source, would provide parasites with bountiful resources to maximise every aspect of their existence, especially reproduction. But parasitism is not a loophole out of life history trade-offs. There is still a finite amount of resources that a parasite can obtain and allocate to its many needs. Living in a resource-rich environment has allowed many parasites to grow to sizes that are of multiple orders of magnitude larger than their free-living relatives. But that does not mean that the underlying economy of nature and its limitations are inapplicable to parasites.

RevDate: 2022-06-23
CmpDate: 2022-06-23

Tvedte ES, Gasser M, Zhao X, et al (2022)

Accumulation of endosymbiont genomes in an insect autosome followed by endosymbiont replacement.

Current biology : CB, 32(12):2786-2795.e5.

Eukaryotic genomes can acquire bacterial DNA via lateral gene transfer (LGT).1 A prominent source of LGT is Wolbachia,2 a widespread endosymbiont of arthropods and nematodes that is transmitted maternally through female germline cells.3,4 The DNA transfer from the Wolbachia endosymbiont wAna to Drosophila ananassae is extensive5-7 and has been localized to chromosome 4, contributing to chromosome expansion in this lineage.6 As has happened frequently with claims of bacteria-to-eukaryote LGT, the contribution of wAna transfers to the expanded size of D. ananassae chromosome 4 has been specifically contested8 owing to an assembly where Wolbachia sequences were classified as contaminants and removed.9 Here, long-read sequencing with DNA from a Wolbachia-cured line enabled assembly of 4.9 Mbp of nuclear Wolbachia transfers (nuwts) in D. ananassae and a 24-kbp nuclear mitochondrial transfer. The nuwts are <8,000 years old in at least two locations in chromosome 4 with at least one whole-genome integration followed by rapid extensive duplication of most of the genome with regions that have up to 10 copies. The genes in nuwts are accumulating small indels and mobile element insertions. Among the highly duplicated genes are cifA and cifB, two genes associated with Wolbachia-mediated Drosophila cytoplasmic incompatibility. The wAna strain that was the source of nuwts was subsequently replaced by a different wAna endosymbiont. Direct RNA Nanopore sequencing of Wolbachia-cured lines identified nuwt transcripts, including spliced transcripts, but functionality, if any, remains elusive.

RevDate: 2022-06-23
CmpDate: 2022-06-23

Gu F, Ai S, Chen Y, et al (2022)

Mutualism promotes insect fitness by fungal nutrient compensation and facilitates fungus propagation by mediating insect oviposition preference.

The ISME journal, 16(7):1831-1842.

Penicillium and Bactrocera dorsalis (oriental fruit fly, Hendel) are major pathogens and pests of citrus fruits, as both of them can cause detrimental losses in citrus production. However, their interaction in the cohabitation of citrus fruits remains elusive. In this study, we revealed a mutualistic relationship between Penicillium and B. dorsalis. We found that insect behaviors can facilitate the entry of fungal pathogens into fruits, and fungal pathogens promote the fitness of insects in return. More specifically, Penicillium could take advantage of the openings left by ovipositors of flies, and adult flies contaminated with Penicillium could spread the fungus to new sites. Moreover, the volatile emissions from fungi could attract gravid flies to the infected site for egg laying. The fungus and B. dorsalis were able to establish mutual interaction, as revealed by the presence of Penicillium DNA in intestinal tracts of flies throughout all larval stages. The fungal partner seemed to promote the emergence rate and shorten the emergence duration of the flies by providing pyridoxine, one of the B group vitamins. Different from previously reported scenarios of strong avoidance of Drosophila and attraction of Aedes aegypti toward Penicillium, our findings unveil a hitherto new paradigm of the mutualism between Penicillium and B. dorsalis, by which both insect and fungus earn benefits to facilitate their propagation.

RevDate: 2022-06-22

Picazo DR, Werner A, Dagan T, et al (2022)

Pangenome evolution in environmentally transmitted symbionts of deep-sea mussels is governed by vertical inheritance.

Genome biology and evolution pii:6613374 [Epub ahead of print].

Microbial pangenomes vary across species; their size and structure are determined by genetic diversity within the population and by gene loss and horizontal gene transfer (HGT). Many bacteria are associated with eukaryotic hosts where the host colonization dynamics may impact bacterial genome evolution. Host-associated lifestyle has been recognized as a barrier to HGT in parentally transmitted bacteria. However, pangenome evolution of environmentally acquired symbionts remains understudied, often due to limitations in symbiont cultivation. Using high-resolution metagenomics, here we study pangenome evolution of two co-occurring endosymbionts inhabiting Bathymodiolus brooksi mussels from a single cold seep. The symbionts, sulfur-oxidizing (SOX) and methane-oxidizing (MOX) gamma-proteobacteria, are environmentally acquired at an early developmental stage and individual mussels may harbor multiple strains of each symbiont species. We found differences in the accessory gene content of both symbionts across individual mussels, which are reflected by differences in symbiont strain composition. Compared to core genes, accessory genes are enriched in genome plasticity functions. We found no evidence for recent horizontal gene transfer between both symbionts. A comparison between the symbiont pangenomes revealed that the MOX population is less diverged and contains fewer accessory genes, supporting that the MOX association with B. brooksi is more recent in comparison to that of SOX. Our results show that the pangenomes of both symbionts evolved mainly by vertical inheritance. We conclude that genome evolution of environmentally transmitted symbionts that associate with individual hosts over their lifetime is affected by a narrow symbiosis where the frequency of HGT is constrained.​.

RevDate: 2022-06-22

Jones MW, Fricke LC, Thorpe CJ, et al (2022)

Infection Dynamics of Cotransmitted Reproductive Symbionts Are Mediated by Sex, Tissue, and Development.

Applied and environmental microbiology [Epub ahead of print].

One of the most prevalent intracellular infections on earth is with Wolbachia, a bacterium in the Rickettsiales that infects a range of insects, crustaceans, chelicerates, and nematodes. Wolbachia is maternally transmitted to offspring and has profound effects on the reproduction and physiology of its hosts, which can result in reproductive isolation, altered vectorial capacity, mitochondrial sweeps, and even host speciation. Some populations stably harbor multiple Wolbachia strains, which can further contribute to reproductive isolation and altered host physiology. However, almost nothing is known about the requirements for multiple intracellular microbes to be stably maintained across generations while they likely compete for space and resources. Here, we use a coinfection of two Wolbachia strains ("wHa" and "wNo") in Drosophila simulans to define the infection and transmission dynamics of an evolutionarily stable double infection. We find that a combination of sex, tissue, and host development contributes to the infection dynamics of the two microbes and that these infections exhibit a degree of niche partitioning across host tissues. wHa is present at a significantly higher titer than wNo in most tissues and developmental stages, but wNo is uniquely dominant in ovaries. Unexpectedly, the ratio of wHa to wNo in embryos does not reflect those observed in the ovaries, indicative of strain-specific transmission dynamics. Understanding how Wolbachia strains interact to establish and maintain stable infections has important implications for the development and effective implementation of Wolbachia-based vector biocontrol strategies, as well as more broadly defining how cooperation and conflict shape intracellular communities. IMPORTANCE Wolbachia is a maternally transmitted intracellular bacterium that manipulates the reproduction and physiology of arthropods, resulting in drastic effects on the fitness, evolution, and even speciation of its hosts. Some hosts naturally harbor multiple strains of Wolbachia that are stably transmitted across generations, but almost nothing is known about the factors that limit or promote these coinfections, which can have profound effects on the host's biology and evolution and are under consideration as an insect-management tool. Here, we define the infection dynamics of a known stably transmitted double infection in Drosophila simulans with an eye toward understanding the patterns of infection that might facilitate compatibility between the two microbes. We find that a combination of sex, tissue, and development all contributes to infection dynamics of the coinfection.

RevDate: 2022-06-22

Song NP, Chen XY, Wang L, et al (2022)

[Village-level landscape succession and its driving mechanism in the agro-pastoral ecotone of Ningxia, China].

Ying yong sheng tai xue bao = The journal of applied ecology, 33(5):1387-1394.

The relationship between human activities and landscape patterns and its regulation are one of the core fields in landscape ecology. The ecological conditions and local cultures of agro-pastoral ecotone are gradually wea-kening due to environmental fluctuations, land-use characteristics (suitable for both farming and grazing), and unstable policy. Therefore, protecting and restoring this semi-natural landscape and the resulting biological, ecolo-gical and cultural functions are becoming increasingly urgent. Here, by combing remote sensing data with interview survey and geographic investigation, we characterized the landscape changes (1964 to 2019) of Wanjigou Village in Yanchi County of Ningxia Hui Autonomous Region, which lay within the agro-pastoral ecotone. We further explored the rules of landscape succession and the underlying natural and social mechanism, as well as the interactions between landscape types. Results showed that Wanjigou Village had been subjected to a succession from the landscape characterized by grassland, arable land and sandy land to that characterized by grassland, shrub land, sandy land and arable land. The change from the competition of landscape function separation to the preliminary integration had formed a definite succession path for grassland-arable land-sandy land-shrub land. The main driving factors were a synthesis of policy, human needs, and environment. Policy often promoted landscape change through large-scale and intensified human activities, while environment promoted landscape succession through internal driving force of ecosystem toward a mutual adaption between landscape and the innate conditions. The driving factors of landscape succession were soil moisture variations caused by the change of soil physical structure, and vegetation change in adapting to new environment. In agro-pastoral ecotone with low resource density, the separation of landscape functions was one of the main reasons for land desertification. The integration and coordination of landscape functions greatly alleviated the situation of ecological deterioration. The critical path to maintain sustainable development of agro-pastoral ecotone was to achieve complementation among landscape types and even integrating with external resources by transforming landscape separation competition into landscape symbiosis.

RevDate: 2022-06-22
CmpDate: 2022-06-22

Cheng K, Wei M, Jin X, et al (2022)

LbAMT3-1, an ammonium transporter induced by arbuscular mycorrhizal in Lycium barbarum, confers tobacco with higher mycorrhizal levels and nutrient uptake.

Plant cell reports, 41(6):1477-1480.

KEY MESSAGE: An ammonium transporter LbAMT3-1 overexpression increases the arbuscular abundance of mycorrhizal that opens the possibility of using LbAMT3-1 in breeding programs to improve symbiotic nutrient uptake in Lycium barbarum. Nitrogen (N) is one of the most essential nutrients required by plants and limits net primary production much of the time in most terrestrial ecosystems. Arbuscular mycorrhizal (AM) fungi can enhance plant nutrient uptake and improve plant productivity in nutrient limit ecosystems. Here, we identified an ammonia transporter, LbAMT3-1, specifically induced by AM fungi in Lycium barbarum. To understand the expression characteristics and biological functions, LbAMT3-1 was cloned, characterized, and overexpressed in Nicotiana tabacum (tobacco). A BLAST search identified the coding sequence for LbAMT3-1 with an open-reading frame of 1473 bp. Reverse transcription polymerase chain reaction (RT-PCR) analysis indicated that, besides mycorrhizal roots, LbAMT3-1 were barely detectable in other tissues, including stems and leaves. Promoter-GUS assay showed that GUS staining was detected in mycorrhizal roots, and GUS activity driven by the LbAMT3-1 promoter was exclusively confined to root cells containing arbuscules. LbAMT3-1 functionally complemented the yeast mutant efficiently, and yeast expressing LbAMT3-1 showed well growth on the agar medium with 0.02, 0.2, and 2 mM NH4+ supply. Moreover, overexpression of LbAMT3-1 in N. tabacum resulted a significant increase in arbuscular abundance and enhanced the nutrient acquisition capacity of mycorrhizal plants. Based on the results of our study, we propose that overexpression of LbAMT3-1 can promote P and N uptake of host plants through the mycorrhizal pathway, and increase the colonization intensity and arbuscular abundance, which opens the possibility of using LbAMT3-1 in breeding programs.

RevDate: 2022-06-21

Lüders A, Dinkelberg A, M Quayle (2022)

Becoming "us" in digital spaces: How online users creatively and strategically exploit social media affordances to build up social identity.

Acta psychologica, 228:103643 pii:S0001-6918(22)00158-5 [Epub ahead of print].

Social media has become a major platform for information-exchange, discourse, and protest and has been linked to a wide range of pressing macro developments. Consequenlty, there is significant interest from scholars as well as from the wider publuc to understand how social media affordances interact with human behavior. In attempts to address these demands, the present article borrows from the social identity tradition to explain group formation processes in Web 2.0 and other online ecosystems. We propose that online users creatively and strategically exploit the affordances provided by platforms and technologies to construct and perform collective selfhood. We emphasize the relevance of community development, norm consensualization, and emotional alignment as recursive dynamic processes that - in symbiosis - provide a functional basis for social identities. We outline these proposed mechanisms based on a corpus of interdisciplinary literature and suggest avenues for future research.

RevDate: 2022-06-20

Heaver SL, Le HH, Tang P, et al (2022)

Characterization of inositol lipid metabolism in gut-associated Bacteroidetes.

Nature microbiology [Epub ahead of print].

Inositol lipids are ubiquitous in eukaryotes and have finely tuned roles in cellular signalling and membrane homoeostasis. In Bacteria, however, inositol lipid production is relatively rare. Recently, the prominent human gut bacterium Bacteroides thetaiotaomicron (BT) was reported to produce inositol lipids and sphingolipids, but the pathways remain ambiguous and their prevalence unclear. Here, using genomic and biochemical approaches, we investigated the gene cluster for inositol lipid synthesis in BT using a previously undescribed strain with inducible control of sphingolipid synthesis. We characterized the biosynthetic pathway from myo-inositol-phosphate (MIP) synthesis to phosphoinositol dihydroceramide, determined the crystal structure of the recombinant BT MIP synthase enzyme and identified the phosphatase responsible for the conversion of bacterially-derived phosphatidylinositol phosphate (PIP-DAG) to phosphatidylinositol (PI-DAG). In vitro, loss of inositol lipid production altered BT capsule expression and antimicrobial peptide resistance. In vivo, loss of inositol lipids decreased bacterial fitness in a gnotobiotic mouse model. We identified a second putative, previously undescribed pathway for bacterial PI-DAG synthesis without a PIP-DAG intermediate, common in Prevotella. Our results indicate that inositol sphingolipid production is widespread in host-associated Bacteroidetes and has implications for symbiosis.

RevDate: 2022-06-21

Kanojiya P, Joshi R, SD Saroj (2022)

The source of carbon and nitrogen differentially affects the survival of Neisseria meningitidis in macrophages and epithelial cells.

Archives of microbiology, 204(7):404.

Neisseria meningitidis is a commensal of human nasopharynx which under certain unidentified conditions could lead to fulminant meningitis or sepsis. Availability of nutrients is essential for bacterial growth and virulence. The metabolic adaptations allow N. meningitidis to utilize host resources, colonize and cause virulence functions which are a crucial for the invasive infection. During colonization meningococci encounters a range of microenvironments involving fluctuations in the availability of carbon and nitrogen source. Therefore, the characterization of virulence factors of N. meningitidis under different microenvironmental conditions is a prime requisite to understand pathogenesis; however, the role of nutrients is not well understood. Here, we explore the expression of virulence phenotype leading to symptomatic behaviour as affected by available carbon and nitrogen sources. We evaluate the effect of carbon or nitrogen source on growth, adhesion to epithelial cells, macrophage infectivity, capsule formation and virulence gene expression of N. meningitidis. It was found that lactate, pyruvate, and acetate facilitate survival of N. meningitidis in macrophages. While in epithelial cells, the survival of N. meningitidis is negatively affected by the presence of lactate and pyruvate.

RevDate: 2022-06-20

Morales DP, Robinson AJ, Pawlowski AC, et al (2022)

Advances and Challenges in Fluorescence in situ Hybridization for Visualizing Fungal Endobacteria.

Frontiers in microbiology, 13:892227.

Several bacteria have long been known to interact intimately with fungi, but molecular approaches have only recently uncovered how cosmopolitan these interactions are in nature. Currently, bacterial-fungal interactions (BFI) are inferred based on patterns of co-occurrence in amplicon sequencing investigations. However, determining the nature of these interactions, whether the bacteria are internally or externally associated, remains a grand challenge in BFI research. Fluorescence in situ hybridization (FISH) is a robust method that targets unique sequences of interest which can be employed for visualizing intra-hyphal targets, such as mitochondrial organelles or, as in this study, bacteria. We evaluate the challenges and employable strategies to resolve intra-hyphal BFI to address pertinent criteria in BFI research, such as culturing media, spatial distribution of bacteria, and abundance of bacterial 16S rRNA copies for fluorescent labeling. While these experimental factors influence labeling and detection of endobacteria, we demonstrate how to overcome these challenges thorough permeabilization, appropriate media choice, and targeted amplification using hybridization chain reaction FISH. Such microscopy imaging approaches can now be utilized by the broader research community to complement sequence-based investigations and provide more conclusive evidence on the nature of specific bacterial-fungal relationships.

RevDate: 2022-06-20

Soni M, Singh AK, Babu KS, et al (2022)

Convolutional neural network based CT scan classification method for COVID-19 test validation.

Smart health (Amsterdam, Netherlands) pii:S2352-6483(22)00031-9 [Epub ahead of print].

Given the novel corona virus discovered in Wuhan, China, in December 2019, due to the high false-negative rate of RT-PCR and the time-consuming to obtain the results, research has proved that computed tomography (CT) has become an auxiliary One of the essential means of diagnosis and treatment of new corona virus pneumonia. Since few COVID-19 CT datasets are currently available, it is proposed to use conditional generative adversarial networks to enhance data to obtain CT datasets with more samples to reduce the risk of over fitting. In addition, a BIN residual block-based method is proposed. The improved U-Net network is used for image segmentation and then combined with multi-layer perception for classification prediction. By comparing with network models such as AlexNet and GoogleNet, it is concluded that the proposed BUF-Net network model has the best performance, reaching an accuracy rate of 93%. Using Grad-CAM technology to visualize the system's output can more intuitively illustrate the critical role of CT images in diagnosing COVID-19. Applying deep learning using the proposed techniques suggested by the above study in medical imaging can help radiologists achieve more effective diagnoses that is the main objective of the research. On the basis of the foregoing, this study proposes to employ CGAN technology to augment the restricted data set, integrate the residual block into the U-Net network, and combine multi-layer perception in order to construct new network architecture for COVID-19 detection using CT images. -19. Given the scarcity of COVID-19 CT datasets, it is proposed that conditional generative adversarial networks be used to augment data in order to obtain CT datasets with more samples and therefore lower the danger of overfitting.

RevDate: 2022-06-20

Kakodkar PV, MG Reddy (2022)

Mu-can: A bacterial-fungal symbiosis that reduces dental caries.

Journal of conservative dentistry : JCD, 25(2):211-212.

RevDate: 2022-06-20

Xie W, Hodge A, Hao Z, et al (2022)

Increased Carbon Partitioning to Secondary Metabolites Under Phosphorus Deficiency in Glycyrrhiza uralensis Fisch. Is Modulated by Plant Growth Stage and Arbuscular Mycorrhizal Symbiosis.

Frontiers in plant science, 13:876192.

Phosphorus (P) is one of the macronutrients limiting plant growth. Plants regulate carbon (C) allocation and partitioning to cope with P deficiency, while such strategy could potentially be influenced by plant growth stage and arbuscular mycorrhizal (AM) symbiosis. In a greenhouse pot experiment using licorice (Glycyrrhiza uralensis) as the host plant, we investigated C allocation belowground and partitioning in roots of P-limited plants in comparison with P-sufficient plants under different mycorrhization status in two plant growth stages. The experimental results indicated that increased C allocation belowground by P limitation was observed only in non-AM plants in the early growth stage. Although root C partitioning to secondary metabolites (SMs) in the non-AM plants was increased by P limitation as expected, trade-off patterns were different between the two growth stages, with C partitioning to SMs at the expense of non-structural carbohydrates (NSCs) in the early growth stage but at the expense of root growth in the late growth stage. These changes, however, largely disappeared because of AM symbiosis, where more root C was partitioned to root growth and AM fungus without any changes in C allocation belowground and partitioning to SMs under P limitations. The results highlighted that besides assisting with plant P acquisition, AM symbiosis may alter plant C allocation and partitioning to improve plant tolerance to P deficiency.

RevDate: 2022-06-20

He C, Han T, Tan L, et al (2022)

Effects of Dark Septate Endophytes on the Performance and Soil Microbia of Lycium ruthenicum Under Drought Stress.

Frontiers in plant science, 13:898378.

In the current study, we explored the effects of dark septate endophytes (DSE) (Neocamarosporium phragmitis, Alternaria chlamydospore, and Microascus alveolaris) on the performance and rhizosphere soil microbial composition of Lycium ruthenicum Murr under drought stress. Differences in plant growth and physiological indexes, soil parameters, and microbial composition under different treatments were studied. Three DSE species could form good symbiotic relationships with L. ruthenicum plants, and the symbionts depended on DSE species and water availability. Inoculation of DSE had the greatest benefit on host plants under drought conditions. In particular, N. phragmitis and A. chlamydospore had a significant positive influence on the biomass, morphological and physiological indexes of host plants. Additionally, the content of arbuscular mycorrhiza (AM) fungi, gram-negative bacteria, and actinomycetes in the soil was significantly elevated after DSE inoculation in the absence of water. Based on a variance decomposition analysis, DSE was the most important factor affecting the growth and physiological parameters of host plants, and DSE inoculation combined with water conditions significantly affected the contents of soil microbial communities. Structural equation model (SEM) analysis showed that the positive effects of DSE on L. ruthenicum varied with DSE species and plant parameters under different water conditions. These results are helpful to understand the ecological function of DSE and its potential application in the cultivation of L. ruthenicum plants in drylands.

RevDate: 2022-06-19

Li Z, Liu Y, L Zhang (2022)

Role of the microbiome in oral cancer occurrence, progression and therapy.

Microbial pathogenesis pii:S0882-4010(22)00251-0 [Epub ahead of print].

The oral cavity, like other digestive or mucosal sites, contains a site-specific microbiome that plays a significant role in maintaining health and homeostasis. Strictly speaking, the gastrointestinal tract starts from the oral cavity, with special attention paid to the specific flora of the oral cavity. In healthy people, the microbiome of the oral microenvironment is governed by beneficial bacteria, that benefit the host by symbiosis. When a microecological imbalance occurs, changes in immune and metabolic signals affect the characteristics of cancer, as well as chronic inflammation, disruption of the epithelial barrier, changes in cell proliferation and cell apoptosis, genomic instability, angiogenesis, and epithelial barrier destruction and metabolic regulation. These pathophysiological changes could result in oral cancer. Rising evidence suggests that oral dysbacteriosis and particular microbes may play a positive role in the evolution, development, progression, and metastasis of oral cancer, for instance, oral squamous cell carcinoma (OSCC) through direct or indirect action.

RevDate: 2022-06-17

Sabbioni G, G Forlani (2022)

The Emerging Role of Proline in the Establishment and Functioning of Legume-Rhizobium Symbiosis.

Frontiers in plant science, 13:888769.

High levels of some enzymes involved in proline synthesis and utilization were early found in soybean nodules, and rhizobial knockout mutants were shown to be defective in inducing nodulation and/or fixing nitrogen, leading to postulate that this amino acid may represent a main substrate for energy transfer from the plant to the symbiont. However, inconsistent results were reported in other species, and several studies suggested that proline metabolism may play an essential role in the legume-Rhizobium symbiosis only under stress. Different mechanisms have been hypothesized to explain the beneficial effects of proline on nodule formation and bacteroid differentiation, yet none of them has been conclusively proven. Here, we summarize these findings, with special emphasis on the occurrence of a legume-specific isoform of δ1-pyrroline-5-carboxylate synthetase, the enzyme that catalyses the rate-limiting step in proline synthesis. Data are discussed in view of recent results connecting the regulation of both, the onset of nodulation and proline metabolism, to the redox status of the cell. Full comprehension of these aspects could open new perspectives to improve the adaptation of legumes to environmental stress.

RevDate: 2022-06-20
CmpDate: 2022-06-20

Bhatia S, Bansal D, Patil S, et al (2022)

A Retrospective Study of Climate Change Affecting Dengue: Evidences, Challenges and Future Directions.

Frontiers in public health, 10:884645.

Climate change is unexpected weather patterns that can create an alarming situation. Due to climate change, various sectors are affected, and one of the sectors is healthcare. As a result of climate change, the geographic range of several vector-borne human infectious diseases will expand. Currently, dengue is taking its toll, and climate change is one of the key reasons contributing to the intensification of dengue disease transmission. The most important climatic factors linked to dengue transmission are temperature, rainfall, and relative humidity. The present study carries out a systematic literature review on the surveillance system to predict dengue outbreaks based on Machine Learning modeling techniques. The systematic literature review discusses the methodology and objectives, the number of studies carried out in different regions and periods, the association between climatic factors and the increase in positive dengue cases. This study also includes a detailed investigation of meteorological data, the dengue positive patient data, and the pre-processing techniques used for data cleaning. Furthermore, correlation techniques in several studies to determine the relationship between dengue incidence and meteorological parameters and machine learning models for predictive analysis are discussed. In the future direction for creating a dengue surveillance system, several research challenges and limitations of current work are discussed.

RevDate: 2022-06-17

Lee J, DW Lee (2022)

Insecticidal Serralysin of Serratia marcescens Is Detoxified in M3 Midgut Region of Riptortus pedestris.

Frontiers in microbiology, 13:913113.

Riptortus pedestris insect indiscriminately acquires not only the symbiotic bacterium Burkholderia insecticola, but also entomopathogens that are abundant in the soil via feeding. However, it is unclear how the host insect survives oral infections of entomopathogens. A previous study suggested that serralysin, a potent virulence factor produced by Serratia marcescens, suppresses cellular immunity by degrading adhesion molecules, thereby contributing to bacterial pathogenesis. Here, we observed that S. marcescens orally administered to R. pedestris stably colonized the insect midgut, while not exhibiting insecticidal activity. Additionally, oral infection with S. marcescens did not affect the host growth or fitness. When co-incubated with the midgut lysates of R. pedestris, serralysin was remarkably degraded. The detoxification activity against serralysin was enhanced in the midgut extract of gut symbiont-colonizing insects. The mRNA expression levels of serralysin genes were negligible in M3-colonizing S. marcescens. M3-colonizing S. marcescens did not produce serralysin toxin. Immunoblot analyses revealed that serralysin was not detected in the M3 midgut region. The findings of our study suggest that orally infected S. marcescens lose entomopathogenicity through host-derived degrading factors and suppression of serralysin.

RevDate: 2022-06-17

Pineda-Mendoza RM, Zúñiga G, López MF, et al (2022)

Rahnella sp., a Dominant Symbiont of the Core Gut Bacteriome of Dendroctonus Species, Has Metabolic Capacity to Degrade Xylan by Bifunctional Xylanase-Ferulic Acid Esterase.

Frontiers in microbiology, 13:911269.

Rahnella sp. ChDrAdgB13 is a dominant member of the gut bacterial core of species of the genus Dendroctonus, which is one of the most destructive pine forest bark beetles. The objectives of this study were identified in Rahnella sp. ChDrAdgB13 genome the glycosyl hydrolase families involved in carbohydrate metabolism and specifically, the genes that participate in xylan hydrolysis, to determine the functionality of a putative endo-1,4-β-D-xylanase, which results to be bifunctional xylanase-ferulic acid esterase called R13 Fae and characterize it biochemically. The carbohydrate-active enzyme prediction revealed 25 glycoside hydrolases, 20 glycosyl transferases, carbohydrate esterases, two auxiliary activities, one polysaccharide lyase, and one carbohydrate-binding module (CBM). The R13 Fae predicted showed high identity to the putative esterases and glycosyl hydrolases from Rahnella species and some members of the Yersiniaceae family. The r13 fae gene encodes 393 amino acids (43.5 kDa), containing a signal peptide, esterase catalytic domain, and CBM48. The R13 Fae modeling showed a higher binding affinity to ferulic acid, α-naphthyl acetate, and arabinoxylan, and a low affinity to starch. The R13 Fae recombinant protein showed activity on α-naphthyl acetate and xylan, but not on starch. This enzyme showed mesophilic characteristics, displaying its optimal activity at pH 6.0 and 25°C. The enzyme was stable at pH from 4.5 to 9.0, retaining nearly 66-71% of its original activity. The half-life of the enzyme was 23 days at 25°C. The enzyme was stable in the presence of metallic ions, except for Hg2+. The products of R13 Fae mediated hydrolysis of beechwood xylan were xylobiose and xylose, manifesting an exo-activity. The results suggest that Rahnella sp. ChDrAdgB13 hydrolyze xylan and its products could be assimilated by its host and other gut microbes as a nutritional source, demonstrating their functional role in the bacterial-insect interaction contributing to their fitness, development, and survival.

RevDate: 2022-06-20
CmpDate: 2022-06-20

Vo VTA, Kim S, Hua TNM, et al (2022)

Iron commensalism of mesenchymal glioblastoma promotes ferroptosis susceptibility upon dopamine treatment.

Communications biology, 5(1):593.

The heterogeneity of glioblastoma multiforme (GBM) leads to poor patient prognosis. Here, we aim to investigate the mechanism through which GBM heterogeneity is coordinated to promote tumor progression. We find that proneural (PN)-GBM stem cells (GSCs) secreted dopamine (DA) and transferrin (TF), inducing the proliferation of mesenchymal (MES)-GSCs and enhancing their susceptibility toward ferroptosis. PN-GSC-derived TF stimulates MES-GSC proliferation in an iron-dependent manner. DA acts in an autocrine on PN-GSC growth in a DA receptor D1-dependent manner, while in a paracrine it induces TF receptor 1 expression in MES-GSCs to assist iron uptake and thus enhance ferroptotic vulnerability. Analysis of public datasets reveals worse prognosis of patients with heterogeneous GBM with high iron uptake than those with other GBM subtypes. Collectively, the findings here provide evidence of commensalism symbiosis that causes MES-GSCs to become iron-addicted, which in turn provides a rationale for targeting ferroptosis to treat resistant MES GBM.

RevDate: 2022-06-20
CmpDate: 2022-06-20

Zapién-Campos R, Bansept F, Sieber M, et al (2022)

On the effect of inheritance of microbes in commensal microbiomes.

BMC ecology and evolution, 22(1):75.

BACKGROUND: Our current view of nature depicts a world where macroorganisms dwell in a landscape full of microbes. Some of these microbes not only transit but establish themselves in or on hosts. Although hosts might be occupied by microbes for most of their lives, a microbe-free stage during their prenatal development seems to be the rule for many hosts. The questions of who the first colonizers of a newborn host are and to what extent these are obtained from the parents follow naturally.

RESULTS: We have developed a mathematical model to study the effect of the transfer of microbes from parents to offspring. Even without selection, we observe that microbial inheritance is particularly effective in modifying the microbiome of hosts with a short lifespan or limited colonization from the environment, for example by favouring the acquisition of rare microbes.

CONCLUSION: By modelling the inheritance of commensal microbes to newborns, our results suggest that, in an eco-evolutionary context, the impact of microbial inheritance is of particular importance for some specific life histories.

RevDate: 2022-06-16

Xiong H, Liu X, Xie Z, et al (2022)

Metabolic Symbiosis-Blocking Nano-combination for Tumor Vascular Normalization Treatment.

Advanced healthcare materials [Epub ahead of print].

The clinical anti-vascular endothelial growth factor (anti-VEGF) drugs and metronomic chemotherapy (MET) induced tumor vascular normalization treatment (TVNT) was easily antagonized by tumor microenvironment metabolic cross-talk between tumor cells and endothelial cells. To overcome this dilemma, nanodrug with the ability of endothelial cells targeted glycolysis inhibition and nanodrug with the ability of tumor cell glycolysis inhibition, anti-VEGF and MET were combined to prepare Nano-combination for TVNT. Besides blocking the metabolic cross-talk between tumor cells and endothelial cells, Nano-combination also induced extensive regulations-widely obstructing the pathways related to angiogenesis, tumor cell proliferation and immunosuppression and breaking the negative sugar-lipid-protein metabolism balance in tumor microenvironment. Thus, stronger and more lasting normalized tumor vascular network and remarkable antitumor efficacy were obtained after treatment, constructing a positive feedback loop between TVNT and anti-tumor therapy. Above all, our study provided a new insight for solving the bottleneck of clinical TVNT. This article is protected by copyright. All rights reserved.

RevDate: 2022-06-16

Yu L, Huang T, Qi X, et al (2022)

Genome-Wide Analysis of Long Non-coding RNAs Involved in Nodule Senescence in Medicago truncatula.

Frontiers in plant science, 13:917840.

Plant long non-coding RNAs (lncRNAs) are widely accepted to play crucial roles during diverse biological processes. In recent years, thousands of lncRNAs related to the establishment of symbiosis, root nodule organogenesis and nodule development have been identified in legumes. However, lncRNAs involved in nodule senescence have not been reported. In this study, senescence-related lncRNAs were investigated in Medicago truncatula nodules by high-throughput strand-specific RNA-seq. A total of 4576 lncRNAs and 126 differentially expressed lncRNAs (DElncRNAs) were identified. We found that more than 60% lncRNAs were associated with transposable elements, especially TIR/Mutator and Helitron DNA transposons families. In addition, 49 DElncRNAs were predicted to be the targets of micro RNAs. Functional analysis showed that the largest sub-set of differently expressed target genes of DElncRNAs were associated with the membrane component. Of these, nearly half genes were related to material transport, suggesting that an important function of DElncRNAs during nodule senescence is the regulation of substance transport across membranes. Our findings will be helpful for understanding the functions of lncRNAs in nodule senescence and provide candidate lncRNAs for further research.

RevDate: 2022-06-16

Normand P, Pujic P, Abrouk D, et al (2022)

Draft Genomes of Nitrogen-fixing Frankia Strains Ag45/Mut15 and AgPM24 Isolated from Root Nodules of Alnus Glutinosa.

Journal of genomics, 10:49-56 pii:jgenv10p0049.

The genomes of two nitrogen-fixing Frankia strains, Ag45/Mut15 and AgPM24, isolated from root nodules of Alnus glutinosa are described as representatives of a novel candidate species. Phylogenomic and ANI analyses confirmed that both strains are related to cluster 1 frankiae, and that both strains belong to a novel species. At 6.4 - 6.7 Mb, their genomes were smaller than those of other cultivated Alnus-infective cluster 1 strains but larger than that of the non-cultivated Alnus-infective cluster 1 Sp+ strain AgTrS that was their closest neighbor as assessed by ANI. Comparative genomic analyses identified genes essential for nitrogen-fixation, gene composition as regards COGs, secondary metabolites clusters and transcriptional regulators typical of those from Alnus-infective cluster 1 cultivated strains in both genomes. There were 459 genes present in other cultivated Alnus-infective strains lost in the two genomes, spread over the whole of the genome, which indicates genome erosion is taking place in these two strains.

RevDate: 2022-06-16

Kumar DN, DS Ghogale (2022)

Intrinsic resistance: A non-negligible bacterial trait.

Annals of medicine and surgery (2012), 78:103949 pii:S2049-0801(22)00709-9.

RevDate: 2022-06-21
CmpDate: 2022-06-17

Souza MM, Junqueira LA, Teofilo-Guedes GS, et al (2022)

Predation of neotropical social wasp nests by ants.

Brazilian journal of biology = Revista brasleira de biologia, 84:e260674 pii:S1519-69842024000100520.

RevDate: 2022-06-21

Hearn LR, Davies OK, MP Schwarz (2022)

Extreme reproductive skew at the dawn of sociality is consistent with inclusive fitness theory but problematic for routes to eusociality.

Proceedings. Biological sciences, 289(1976):20220652.

To understand the earliest stages of social evolution, we need to identify species that are undergoing the initial steps into sociality. Amphylaeus morosus is the only unambiguously known social species in the bee family Colletidae and represents an independent origin of sociality within the Apoidea. This allows us to investigate the selective factors promoting the transition from solitary to social nesting. Using genome-wide SNP genotyping, we infer robust pedigree relationships to identify maternity of brood and intracolony relatedness for colonies at the end of the reproductive season. We show that A. morosus forms both matrifilial and full-sibling colonies, both involving complete or almost complete monopolization over reproduction. In social colonies, the reproductive primary was also the primary forager with the secondary female remaining in the nest, presumably as a guard. Social nesting provided significant protection against parasitism and increased brood survivorship in general. We show that secondary females gain large indirect fitness benefits from defensive outcomes, enough to satisfy the conditions of inclusive fitness theory, despite an over-production of males in social colonies. These results suggest an avenue to sociality that involves high relatedness and, very surprisingly, extreme reproductive skew in its earliest stages and raises important questions about the evolutionary steps in pathways to eusociality.

RevDate: 2022-06-21

Bordenstein SR, SR Bordenstein (2022)

Widespread phages of endosymbionts: Phage WO genomics and the proposed taxonomic classification of Symbioviridae.

PLoS genetics, 18(6):e1010227 pii:PGENETICS-D-21-01513.

Wolbachia are the most common obligate, intracellular bacteria in animals. They exist worldwide in arthropod and nematode hosts in which they commonly act as reproductive parasites or mutualists, respectively. Bacteriophage WO, the largest of Wolbachia's mobile elements, includes reproductive parasitism genes, serves as a hotspot for genetic divergence and genomic rearrangement of the bacterial chromosome, and uniquely encodes a Eukaryotic Association Module with eukaryotic-like genes and an ensemble of putative host interaction genes. Despite WO's relevance to genome evolution, selfish genetics, and symbiotic applications, relatively little is known about its origin, host range, diversification, and taxonomic classification. Here we analyze the most comprehensive set of 150 Wolbachia and phage WO assemblies to provide a framework for discretely organizing and naming integrated phage WO genomes. We demonstrate that WO is principally in arthropod Wolbachia with relatives in diverse endosymbionts and metagenomes, organized into four variants related by gene synteny, often oriented opposite the putative origin of replication in the Wolbachia chromosome, and the large serine recombinase is an ideal typing tool to distinguish the four variants. We identify a novel, putative lytic cassette and WO's association with a conserved eleven gene island, termed Undecim Cluster, that is enriched with virulence-like genes. Finally, we evaluate WO-like Islands in the Wolbachia genome and discuss a new model in which Octomom, a notable WO-like Island, arose from a split with WO. Together, these findings establish the first comprehensive Linnaean taxonomic classification of endosymbiont phages, including non-Wolbachia phages from aquatic environments, that includes a new family and two new genera to capture the collective relatedness of these viruses.

RevDate: 2022-06-17
CmpDate: 2022-06-17

Pandit A, Johny L, Srivastava S, et al (2022)

Recreating in vitro tripartite mycorrhizal associations through functional bacterial biofilms.

Applied microbiology and biotechnology, 106(11):4237-4250.

Arbuscular mycorrhizal fungi (AMF) and beneficial bacteria are found naturally associated with most terrestrial plant roots. While it is now well known that bacteria colonize AMF and can form aggregates and biofilms, little is known about how interactions between bacterial communities and AMF take place under both in situ and in vitro conditions. We investigated the impact of inoculation with AMF-associated bacteria (AABs) of AMF by in vitro recreation of the interaction on synthetic growth media in a two-compartment Petri plate system. The inoculated AABs were found to be associated with the mycorrhizal co-culture and were found to migrate along growing AMF hyphae and to be associated with the spore surface. AABs differentially influenced the growth of the AMF and their functional capability demonstrated by analysis of phosphate solubilization, nitrogen fixation, and biofilm formation. We have thus characterized these important interactions adding to a further understanding of the synergistic relationship between the two cross-kingdom microbial partners. KEY POINTS: • An in vitro assay was utilized to recreate functional biofilms with AMF-associated bacteria. • AMF-associated bacteria formed a biofilm and enhanced sporulation of Rhizophagus irregularis. • AMF-bacterial interactions through biofilm formation influence the functional capability of both partners.

RevDate: 2022-06-21
CmpDate: 2022-06-21

Ben Romdhane S, De Lajudie P, Fuhrmann JJ, et al (2022)

Potential role of rhizobia to enhance chickpea-growth and yield in low fertility-soils of Tunisia.

Antonie van Leeuwenhoek, 115(7):921-932.

Plant growth-promoting rhizobacteria are bacteria that improve plant growth and reduce plant pathogen damages. In this study, 100 nodule bacteria were isolated from chickpea, screened for their plant growth-promoting (PGP) traits and then characterised by PCR-RFLP of 16 S rDNA. Results showed that most of the slow-growing isolates fixed nitrogen but those exhibiting fast-growth did not. Fourteen isolates solubilized inorganic phosphorus, 16 strains produced siderophores, and 17 strains produced indole acetic acid. Co-culture experiments identified three strains having an inhibitory effect against Fusarium oxysporum, the primary pathogenic fungus for chickpea in Tunisia. Rhizobia with PGP traits were assigned to Mesorhizobium ciceri, Mesorhizobium mediterraneum, Sinorhizobium meliloti and Agrobacterium tumefaciens. We noted that PGP activities were differentially distributed between M. ciceri and M. mediterraneum. The region of Mateur in northern Tunisia, with clay-silty soil, was the origin of 53% of PGP isolates. Interestingly, we found that S. meliloti and A. tumefaciens strains did not behave as parasitic nodule-bacteria but as PGP rhizobacteria useful for chickpea nutrition and health. In fact, S. meliloti strains could solubilize phosphorus, produce siderophore and auxin. The A. tumefaciens strains could perform the previous PGP traits and inhibit pathogen growth also. Finally, one candidate strain of M. ciceri (LL10)-selected for its highest symbiotic nitrogen fixation and phosphorus solubilization-was used for field experiment. The LL10 inoculation increased grain yield more than three-fold. These finding showed the potential role of rhizobia to be used as biofertilizers and biopesticides, representing low-cost and environment-friendly inputs for sustainable agriculture.

RevDate: 2022-06-17
CmpDate: 2022-06-17

Nascimento da Silva J, Calixto Conceição C, Cristina Ramos de Brito G, et al (2022)

Wolbachia pipientis modulates metabolism and immunity during Aedes fluviatilis oogenesis.

Insect biochemistry and molecular biology, 146:103776.

Wolbachia pipientis is a maternally transmitted bacterium that mostly colonizes arthropods, including the mosquito Aedes fluviatilis, potentially affecting different aspects of host physiology. This intracellular bacterium prefers gonadal tissue cells, interfering with the reproductive cycle of insects, arachnids, crustaceans, and nematodes. Wolbachia's ability to modulate the host's reproduction is related to its success in prevalence and frequency. Infecting oocytes is essential for vertical propagation, ensuring its presence in the germline. The mosquito Ae. fluviatilis is a natural host for this bacterium and therefore represents an excellent experimental model in the effort to understand host-symbiont interactions and the mutual metabolic regulation. The aim of this study was to comparatively describe metabolic changes in naturally Wolbachia-infected and uninfected ovaries of Ae. fluviatilis during the vitellogenic period of oogenesis, thus increasing the knowledge about Wolbachia parasitic/symbiotic mechanisms.

RevDate: 2022-06-21
CmpDate: 2022-06-21

Kaur R, Singh S, N Joshi (2022)

Pervasive Endosymbiont Arsenophonus Plays a Key Role in the Transmission of Cotton Leaf Curl Virus Vectored by Asia II-1 Genetic Group of Bemisia tabaci.

Environmental entomology, 51(3):564-577.

Insects often coevolved with their mutualistic partners such as gut endosymbionts, which play a key in the physiology of host. Studies on such interactions between Bemisia tabaci and its primary and secondary endosymbionts have gained importance due to their indispensable roles in the biology of this insect. Present study reports the predominance of two secondary endosymbionts, Arsenophonus and Cardinium in the Asia II-1 genetic group of whitefly and elucidates their role in the transmission of its vectored Cotton leaf curl virus. Selective elimination of endosymbionts was optimized using serial concentration of ampicillin, chloramphenicol, kanamycin, tetracycline, and rifampicin administered to viruliferous whiteflies through sucrose diet. Primary endosymbiont, Portiera was unresponsive to all the antibiotics, however, rifampicin and tetracycline at 90 μg/ml selectively eliminated Arsenophonus from the whitefly. Elimination of Arsenophonus resulted in significant decrease in virus titer from viruliferous whitefly, further the CLCuV transmission efficiency of these whiteflies was significantly reduced compared to the control flies. Secondary endosymbiont, Cardinium could not be eliminated completely even with higher concentrations of antibiotics. Based on the findings, Arsenophonus plays a key role in the retention and transmission of CLCuV in the Asia II-1 genetic group of B. tabaci, while the role of Cardinium could not be established due to its unresponsiveness to antibiotics.

RevDate: 2022-06-21
CmpDate: 2022-06-21

Krumbholz J, Ishida K, Baunach M, et al (2022)

Deciphering Chemical Mediators Regulating Specialized Metabolism in a Symbiotic Cyanobacterium.

Angewandte Chemie (International ed. in English), 61(26):e202204545.

Genomes of cyanobacteria feature a variety of cryptic biosynthetic pathways for complex natural products, but the peculiarities limiting the discovery and exploitation of the metabolic dark matter are not well understood. Here we describe the discovery of two cell density-dependent chemical mediators, nostoclide and nostovalerolactone, in the symbiotic model strain Nostoc punctiforme, and demonstrate their pronounced impact on the regulation of specialized metabolism. Through transcriptional, bioinformatic and labeling studies we assigned two adjacent biosynthetic gene clusters to the biosynthesis of the two polyketide mediators. Our findings provide insight into the orchestration of specialized metabolite production and give lessons for the genomic mining and high-titer production of cyanobacterial bioactive compounds.

RevDate: 2022-06-13

Bennett AE, K Groten (2022)

The Costs and Benefits of Plant-Arbuscular Mycorrhizal Fungal Interactions.

Annual review of plant biology, 73:649-672.

The symbiotic interaction between plants and arbuscular mycorrhizal (AM) fungi is often perceived as beneficial for both partners, though a large ecological literature highlights the context dependency of this interaction. Changes in abiotic variables, such as nutrient availability, can drive the interaction along the mutualism-parasitism continuum with variable outcomes for plant growth and fitness. However, AM fungi can benefit plants in more ways than improved phosphorus nutrition and plant growth. For example, AM fungi can promote abiotic and biotic stress tolerance even when considered parasitic from a nutrient provision perspective. Other than being obligate biotrophs, very little is known about the benefits AM fungi gain from plants. In this review, we utilize both molecular biology and ecological approaches to expand our understanding of the plant-AM fungal interaction across disciplines.

RevDate: 2022-06-15

Shi X, Qin T, Qu Y, et al (2022)

Infection by endophytic Epichloë sibirica was associated with activation of defense hormone signal transduction pathways and enhanced pathogen resistance in the grass Achnatherum sibiricum.

Phytopathology [Epub ahead of print].

Epichloë endophytes can improve the resistance of host grasses to pathogenic fungi, but the underlying mechanisms remain largely unknown. Here, we used phytohormone quantifications, gene expression analysis and pathogenicity experiments to investigate the effect of Epichloë sibirica on the resistance of Achnatherum sibiricum to Curvularia lunata pathogens. Comparison of gene expression patterns between endophyte-infected and endophyte-free leaves revealed that endophyte infection was associated with significant induction of 1758 and 765 differentially expressed genes in the host before and after pathogen inoculation, respectively. Functional analysis of the differentially expressed genes suggested that endophyte infection may activate the constitutive resistance of the host by increasing photosynthesis, enhancing the ability to scavenge reactive oxygen species, and actively regulating the expression of genes with function related to disease resistance. We found that endophyte infection was associated with induction of the expression of genes involved in the biosynthesis pathways of jasmonic acid, ethylene and pipecolic acid and amplified the defense response of jasmonic acid/ethylene co-regulated EIN/ERF1 transduction pathway and Pip-mediated TGA transduction pathway. Phytohormone quantifications showed that endophyte infection was associated with significant accumulation of jasmonic acid, ethylene and pipecolic acid after pathogen inoculation. Exogenous phytohormone treatments confirmed that the disease index of plants was negatively related to both jasmonic acid and ethylene concentrations. Our results demonstrate that endophyte infection can not only improve the constitutive resistance of the host to phytopathogens before pathogen inoculation but also be associated with enhanced systemic resistance of the host to necrotrophs after C. lunata inoculation.

RevDate: 2022-06-15

Martini MC, Vacca C, Torres Tejerizo GA, et al (2022)

ubiF is involved in acid stress tolerance and symbiotic competitiveness in Rhizobium favelukesii LPU83.

Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology] [Epub ahead of print].

The acidity of soils significantly reduces the productivity of legumes mainly because of the detrimental effects of hydrogen ions on the legume plants, leading to the establishment of an inefficient symbiosis and poor biological nitrogen fixation. We recently reported the analysis of the fully sequenced genome of Rhizobium favelukesii LPU83, an alfalfa-nodulating rhizobium with a remarkable ability to grow, nodulate and compete in acidic conditions. To gain more insight into the genetic mechanisms leading to acid tolerance in R. favelukesii LPU83, we constructed a transposon mutant library and screened for mutants displaying a more acid-sensitive phenotype than the parental strain. We identified mutant Tn833 carrying a single-transposon insertion within LPU83_2531, an uncharacterized short ORF located immediately upstream from ubiF homolog. This gene encodes a protein with an enzymatic activity involved in the biosynthesis of ubiquinone. As the transposon was inserted near the 3' end of LPU83_2531 and these genes are cotranscribed as a part of the same operon, we hypothesized that the phenotype in Tn833 is most likely due to a polar effect on ubiF transcription.We found that a mutant in ubiF was impaired to grow at low pH and other abiotic stresses including 5 mM ascorbate and 0.500 mM Zn2+. Although the ubiF mutant retained the ability to nodulate alfalfa and Phaseolus vulgaris, it was unable to compete with the R. favelukesii LPU83 wild-type strain for nodulation in Medicago sativa and P. vulgaris, suggesting that ubiF is important for competitiveness. Here, we report for the first time an ubiF homolog being essential for nodulation competitiveness and tolerance to specific stresses in rhizobia.

RevDate: 2022-06-15

Pendse S, Vaidya A, V Kale (2022)

Clinical applications of pluripotent stem cells and their derivatives: current status and future perspectives.

Regenerative medicine [Epub ahead of print].

Pluripotent stem cells (PSCs) can differentiate into specific cell types and thus hold great promise in regenerative medicine to treat certain diseases. Hence, several studies have been performed harnessing their salutary properties in regenerative medicine. Despite several challenges associated with the clinical applications of PSCs, worldwide efforts are harnessing their potential in the regeneration of damaged tissues. Several clinical trials have been performed using PSCs or their derivatives. However, the delay in publishing the data obtained in the trials has led to a lack of awareness about their outcomes, resulting in apprehension about cellular therapies. Here, the authors review the published papers containing data from recent clinical trials done with PSCs. PSC-derived extracellular vesicles hold great potential in regenerative therapy. Since published papers containing the data obtained in clinical trials on PSC-derived extracellular vesicles are not available yet, the authors have reviewed some of the pre-clinical work done with them.

RevDate: 2022-06-14

Jackson R, Monnin D, Patapiou PA, et al (2022)

Convergent evolution of a labile nutritional symbiosis in ants.

The ISME journal [Epub ahead of print].

Ants are among the most successful organisms on Earth. It has been suggested that forming symbioses with nutrient-supplementing microbes may have contributed to their success, by allowing ants to invade otherwise inaccessible niches. However, it is unclear whether ants have evolved symbioses repeatedly to overcome the same nutrient limitations. Here, we address this question by comparing the independently evolved symbioses in Camponotus, Plagiolepis, Formica and Cardiocondyla ants. Our analysis reveals the only metabolic function consistently retained in all of the symbiont genomes is the capacity to synthesise tyrosine. We also show that in certain multi-queen lineages that have co-diversified with their symbiont for millions of years, only a fraction of queens carry the symbiont, suggesting ants differ in their colony-level reliance on symbiont-derived resources. Our results imply that symbioses can arise to solve common problems, but hosts may differ in their dependence on symbionts, highlighting the evolutionary forces influencing the persistence of long-term endosymbiotic mutualisms.

RevDate: 2022-06-15
CmpDate: 2022-05-31

Rhodes KA, Ma MC, Rendón MA, et al (2022)

Neisseria genes required for persistence identified via in vivo screening of a transposon mutant library.

PLoS pathogens, 18(5):e1010497 pii:PPATHOGENS-D-21-02330.

The mechanisms used by human adapted commensal Neisseria to shape and maintain a niche in their host are poorly defined. These organisms are common members of the mucosal microbiota and share many putative host interaction factors with Neisseria meningitidis and Neisseria gonorrhoeae. Evaluating the role of these shared factors during host carriage may provide insight into bacterial mechanisms driving both commensalism and asymptomatic infection across the genus. We identified host interaction factors required for niche development and maintenance through in vivo screening of a transposon mutant library of Neisseria musculi, a commensal of wild-caught mice which persistently and asymptomatically colonizes the oral cavity and gut of CAST/EiJ and A/J mice. Approximately 500 candidate genes involved in long-term host interaction were identified. These included homologs of putative N. meningitidis and N. gonorrhoeae virulence factors which have been shown to modulate host interactions in vitro. Importantly, many candidate genes have no assigned function, illustrating how much remains to be learned about Neisseria persistence. Many genes of unknown function are conserved in human adapted Neisseria species; they are likely to provide a gateway for understanding the mechanisms allowing pathogenic and commensal Neisseria to establish and maintain a niche in their natural hosts. Validation of a subset of candidate genes confirmed a role for a polysaccharide capsule in N. musculi persistence but not colonization. Our findings highlight the potential utility of the Neisseria musculi-mouse model as a tool for studying the pathogenic Neisseria; our work represents a first step towards the identification of novel host interaction factors conserved across the genus.

RevDate: 2022-06-14

Pekkoh J, Chaichana C, Thurakit T, et al (2022)

Dual-Bioaugmentation Strategy to Enhance the Formation of Algal-Bacteria Symbiosis Biofloc in Aquaculture Wastewater Supplemented with Agricultural Wastes as an Alternative Nutrient Sources and Biomass Support Materials.

Bioresource technology pii:S0960-8524(22)00798-2 [Epub ahead of print].

This study performs an integrated evaluation of the formation and distribution of algal-bacterial bioflocs in aquaculture wastewater supplemented with agricultural waste, together with an assessment of their behavior in the microbial community and of the water quality of the system in which a new bioaugmentation strategy was applied. Results indicated that the dual bioaugmentation strategy via the consortium addition of bacteria and microalgae had the highest formation performance, providing the most compact biofloc structure (0.59 g/L), excellent settleability (71.91%), and a large particle diameter (4.25 mm). The fed-batch supplementation of molasses and rice bran, in terms of changes in the values of COD, NH4+, NO3-, and PO43-, stimulated the formation of biofloc through algal-bacterial bioflocs and microbe-rice bran complexes within a well-established microbial community. These findings provide new insight into the influence of bioaugmentation on the formation of an innovative algal-bacterial biofloc.

RevDate: 2022-06-14

Thompson L, Swift SOI, Egan CP, et al (2022)

Traits and tradeoffs among non-native ectomycorrhizal fungal symbionts affect pine seedling establishment in a Hawaiian co-invasion landscape.

Molecular ecology [Epub ahead of print].

Pine invasions lead to losses of native biodiversity and ecosystem function, but pine invasion success is often linked to co-invading non-native ectomycorrhizal (EM) fungi. How the community composition, traits, and distributions of these fungi vary over the landscape and how this in-turn affects pine success is understudied. A greenhouse bioassay experiment was performed to test the effects of changes in EM fungal community structure from a pine plantation, to an invasion front to currently pine-free areas on percent root colonization and seedling biomass. Soils were also analyzed by qPCR to determine changes in inoculum and spore density over distance for a common co-invading EM fungus, Suillus pungens. Percent colonization increased with distance from the plantation, which corresponded with an increase in seedling biomass and stark changes in EM fungal community membership where Suillus spp. dominated currently pine-free areas. However, there was a negative relationship between S. pungens inoculum potential versus root colonization over distance. We conclude that the success of pine invasions is facilitated by specific traits of Suillus spp., but that the success of Suillus is contingent on a lack of competition with other ectomycorrhizal fungi.

RevDate: 2022-06-13

Amorim K, Loick-Wilde N, Yuen B, et al (2022)

Chemoautotrophy, symbiosis and sedimented diatoms support high biomass of benthic molluscs in the Namibian shelf.

Scientific reports, 12(1):9731.

The molluscs Lucinoma capensis, Lembulus bicuspidatus and Nassarius vinctus are highly abundant in Namibian oxygen minimum zone sediments. To understand which nutritional strategies allow them to reach such impressive abundances in this extreme habitat we investigated their trophic diversity, including a chemosymbiosis in L. capensis, focussing on nitrogen biochemical pathways of the symbionts. We combined results of bulk nitrogen and carbon (δ13C and δ15N) and of compound-specific isotope analyses of amino acid nitrogen (AAs-δ15NPhe and δ15NGlu), with 16S rRNA gene sequencing of L. capensis tissues and also with exploratory results of ammonium, nitrate and nitrite turnover. The trophic position (TP) of the bivalve L. capensis is placed between autotrophy and mixotrophy, consistent with its proposed symbiosis with sulfur-oxidizing Candidatus Thiodiazotropha sp. symbionts. The symbionts are here revealed to perform nitrate reduction and ammonium uptake, with clear indications of ammonium host-symbionts recycling, but surprisingly unable to fix nitrogen. The TP of the bivalve L. bicuspidatus is placed in between mixotrophy and herbivory. The TP of the gastropod N. vinctus reflected omnivory. Multiple lines of evidences in combination with current ecosystem knowledge point to sedimented diatoms as important components of L. bicuspidatus and N. vinctus' diet, likely supplemented at times with chemoautotrophic bacteria. This study highlights the importance of benthic-pelagic coupling that fosters the dietary base for macrozoobenthos in the OMZ. It further unveils that, in contrast to all shallow water lucinid symbionts, deeper water lucinid symbionts rely on ammonium assimilation rather than dinitrogen fixation to obtain nitrogen for growth.

RevDate: 2022-06-14
CmpDate: 2022-06-14

Strunov A, Lerch S, Blanckenhorn WU, et al (2022)

Complex effects of environment and Wolbachia infections on the life history of Drosophila melanogaster hosts.

Journal of evolutionary biology, 35(6):788-802.

Wolbachia bacteria are common endosymbionts of many arthropods found in gonads and various somatic tissues. They manipulate host reproduction to enhance their transmission and confer complex effects on fitness-related traits. Some of these effects can serve to increase the survival and transmission efficiency of Wolbachia in the host population. The Wolbachia-Drosophila melanogaster system represents a powerful model to study the evolutionary dynamics of host-microbe interactions and infections. Over the past decades, there has been a replacement of the ancestral wMelCS Wolbachia variant by the more recent wMel variant in worldwide D. melanogaster populations, but the reasons remain unknown. To investigate how environmental change and genetic variation of the symbiont affect host developmental and adult life-history traits, we compared effects of both Wolbachia variants and uninfected controls in wild-caught D. melanogaster strains at three developmental temperatures. While Wolbachia did not influence any developmental life-history traits, we found that both lifespan and fecundity of host females were increased without apparent fitness trade-offs. Interestingly, wMelCS-infected flies were more fecund than uninfected and wMel-infected flies. By contrast, males infected with wMel died sooner, indicating sex-specific effects of infection that are specific to the Wolbachia variant. Our study uncovered complex temperature-specific effects of Wolbachia infections, which suggests that symbiont-host interactions in nature are strongly dependent on the genotypes of both partners and the thermal environment.

RevDate: 2022-06-13

Nadal-Jimenez P, Siozios S, Halliday N, et al (2022)

Symbiopectobacterium purcellii, gen. nov., sp. nov., isolated from the leafhopper Empoasca decipiens.

International journal of systematic and evolutionary microbiology, 72(6):.

Bacterial endosymbionts are found in multiple arthropod species, where they play crucial roles as nutritional symbionts, defensive symbionts or reproductive parasites. Recent work has highlighted a new clade of heritable microbes within the gammaproteobacteria that enter into both obligate and facultative symbioses, with an obligately required unculturable symbiont recently given the name Candidatus Symbiopectobacterium. In this study, we describe a culturable rod shaped non-flagellated bacterial symbiont from this clade isolated from the leafhopper Empoasca decipiens. The symbiont is related to the transovarially transmitted 'BEV' bacterium that was first isolated from the leafhopper Euscelidius variegatus by Alexander Purcell, and we therefore name the symbiont Symbiopectobacterium purcellii sp. nov., gen. nov. We further report the closed genome sequence for S. purcellii. The genome is atypical for a heritable microbe, being large in size, without profound AT bias and with little evidence of pseudogenization. The genome is predicted to encode Type II, III and VI secretion systems and associated effectors and a non-ribosomal peptide synthase array likely to produce bioactive small molecules. The predicted metabolism is more complete than for other symbionts in the Symbiopectobacterium clade, and the microbe is predicted to synthesize a range of B vitamins. However, Biolog plate results indicate that the metabolism is depauperate compared to the sister clade, represented by Pectobacterium carotovorum. A quorum-sensing pathway related to that of Pectobacterium species (containing an overlapping expI-expR1 pair in opposite directions and a "solo" expR2) is evidenced, and LC-MS/MS analysis reveals the presence of 3-hydroxy-C10-HSL as the sole N-acylhomoserine lactone (AHL) in our strain. This AHL profile is profoundly divergent from that of other Erwinia and Pectobacterium species which produce mostly 3-oxo-C6- and 3-oxo-C8-HSL and could aid group identification. Thus, this microbe denotes one that has lost certain pathways associated with a saprophytic lifestyle but represents an important baseline against which to compare other members of the genus Symbiopectobacterium that show more profound integration into host biology. The type strain of Symbiopectobacterium purcellii gen. nov., sp. nov. is SyEd1T (LMG 32449T=CECT 30436T).

RevDate: 2022-06-13

Newell PD, Preciado LM, CG Murphy (Jr) (2022)

A Functional Analysis of the Purine Salvage Pathway in Acetobacter fabarum.

Journal of bacteriology [Epub ahead of print].

Acetobacter species are a major component of the gut microbiome of the fruit fly Drosophila melanogaster, a widely used model organism. While a range of studies have illuminated impacts of Acetobacter on their hosts, less is known about how association with the host impacts bacteria. A previous study identified that a purine salvage locus was commonly found in Acetobacter associated with Drosophila. In this study, we sought to verify the functions of predicted purine salvage genes in Acetobacter fabarum DsW_054 and to test the hypothesis that these bacteria can utilize host metabolites as a sole source of nitrogen. Targeted gene deletion and complementation experiments confirmed that genes encoding xanthine dehydrogenase (xdhB), urate hydroxylase (urhA), and allantoinase (puuE) were required for growth on their respective substrates as the sole source of nitrogen. Utilization of urate by Acetobacter is significant because this substrate is the major nitrogenous waste product of Drosophila, and its accumulation in the excretory system is detrimental to both flies and humans. The potential significance of our findings for host purine homeostasis and health are discussed, as are the implications for interactions among microbiota members, which differ in their capacity to utilize host metabolites for nitrogen. IMPORTANCE Acetobacter are commonly found in the gut microbiota of fruit flies, including Drosophila melanogaster. We evaluated the function of purine salvage genes in Acetobacter fabarum to test the hypothesis that this bacterium can utilize host metabolites as a source of nitrogen. Our results identify functions for three genes required for growth on urate, a major host waste product. The utilization of this and other Drosophila metabolites by gut bacteria may play a role in their survival in the host environment. Future research into how microbial metabolism impacts host purine homeostasis may lead to therapies because urate accumulation in the excretory system is detrimental to flies and humans.

RevDate: 2022-06-13

Li J, Zou Y, Yang J, et al (2022)

Cultured Bacteria Provide Insight into the Functional Potential of the Coral-Associated Microbiome.

mSystems [Epub ahead of print].

Improving the availability of representative isolates from the coral microbiome is essential for investigating symbiotic mechanisms and applying beneficial microorganisms to improve coral health. However, few studies have explored the diversity of bacteria which can be isolated from a single species. Here, we isolated a total of 395 bacterial strains affiliated with 49 families across nine classes from the coral Pocillopora damicornis. Identification results showed that most of the strains represent potential novel bacterial species or genera. We also sequenced and assembled the genomes of 118 of these isolates, and then the putative functions of these isolates were identified based on genetic signatures derived from the genomes and this information was combined with isolate-specific phenotypic data. Genomic information derived from the isolates identified putative functions including nitrification and denitrification, dimethylsulfoniopropionate transformation, and supply of fixed carbon, amino acids, and B vitamins which may support their eukaryotic partners. Furthermore, the isolates contained genes associated with chemotaxis, biofilm formation, quorum sensing, membrane transport, signal transduction, and eukaryote-like repeat-containing and cell-cell attachment proteins, all of which potentially help the bacterium establish association with the coral host. Our work expands on the existing culture collection of coral-associated bacteria and provides important information on the metabolic potential of these isolates which can be used to refine understanding of the role of bacteria in coral health and are now available to be applied to novel strategies aimed at improving coral resilience through microbiome manipulation. IMPORTANCE Microbes underpin the health of corals which are the building blocks of diverse and productive reef ecosystems. Studying the culturable fraction of coral-associated bacteria has received less attention in recent times than using culture-independent molecular methods. However, the genomic and phenotypic characterization of isolated strains allows assessment of their functional role in underpinning coral health and identification of beneficial microbes for microbiome manipulation. Here, we isolated 395 bacterial strains from tissues of Pocillopora damicornis with many representing potentially novel taxa and therefore providing a significant contribution to coral microbiology through greatly enlarging the existing cultured coral-associated bacterial bank. Through analysis of the genomes obtained in this study for the coral-associated bacteria and coral host, we elucidate putative metabolic linkages and symbiotic establishment. The results of this study will help to elucidate the role of specific isolates in coral health and provide beneficial microbes for efforts aimed at improving coral health.

RevDate: 2022-06-13

Matela H, Panchal P, Yadav SS, et al (2022)

A critical comparison of the Indian school food and nutrition guidelines with the WHO-nutrition friendly school initiative and the review of existing implementation scenario.

Nutrition and health [Epub ahead of print].

Background: The school-based food and nutrition guidelines approach has the potential to combat undernutrition, overnutrition and micronutrient deficiencies among children and adolescents and set the foundation for a healthy adult lifestyle. Aim: To critically compare the Nutrition Friendly School Initiative (NFSI) of the World Health Organization (WHO) with the Food Safety and Standards Authority of India (FSSAI) and the Indian Academy of Pediatrics (IAP) guidelines to gauge the strengths and limitations. Additionally, to summarize the existing studies on implementing school food and nutrition guidelines. Methods: Policy documents of the above guidelines were critically evaluated, and narrative analysis was conducted. An electronic search was conducted for full-text research articles published in the English language between January 2007 to September 2021 in Science Direct, PubMed, Web of Science, and SCOPUS databases. Results: Upon critical comparison of the three guidelines, it was found that the NFSI and FSSAI guidelines shared similarities in many components and the FSSAI guidelines, if implemented adequately, could improve the school food environment and combat the triple malnutrition burden in India. After screening the articles based on the eligibility criteria, 11 studies were included in the preparation of the review. Studies reported partial or inadequate implementation and poor compliance with the guidelines or approach. A few studies identified barriers to guideline implementation. Conclusion: Implementation of school food and nutrition guidelines could improve the nutritional outcomes in children and adolescents. To sustain the effective implementation, adequate resources and preparedness are essential in low-and middle-income countries, including India.

RevDate: 2022-06-13

Cui Y (2022)

Landscaping Agricultural and Animal Husbandry Production Park Using Lightweight Deep Reinforcement Learning under Circular Symbiosis Concept.

Computational intelligence and neuroscience, 2022:8410996.

The paper intends to optimize the landscape of the agricultural and animal husbandry (AG and AH) production park using the deep reinforcement learning (DRL) model under circular symbiosis. Therefore, after reviewing the relevant literature, decision tree evolutionary algorithm, and ensemble learning criteria, this paper studies and constructs the circular symbiotic industrial chain. Then, an experiment of landscaping the park and optimizing the production is made with full consideration of practical institutions. Finally, the numerical results show that the yield of several crops has been significantly improved after the landscape optimization by the proposed DRL model. Remarkably, the increase in rice yield is the most prominent. The yield of rice and wheat was about 12 kg before optimization and 18 kg after DRL model optimization, which has increased by 6 kg. This research has important reference value for improving the output efficiency of AG and AH products.

RevDate: 2022-06-13

Qin H, Li G, Xu X, et al (2022)

The role of oral microbiome in periodontitis under diabetes mellitus.

Journal of oral microbiology, 14(1):2078031 pii:2078031.

Periodontitis is among most common human inflammatory diseases and characterized by destruction of tooth-supporting tissues that will eventually lead to tooth loss. Diabetes mellitus (DM) is a group of metabolic disorders characterized by chronic hyperglycemia which results from defects in insulin secretion and/or insulin resistance. Numerous studies have provided evidence for the inter-relationship between DM and periodontitis that has been considered as the sixth most frequent complication of DM. However, the mechanisms are not fully understood yet. The impact of DM on periodontitis through hyperglycemia and inflammatory pathways is well described, but the effects of DM on oral microbiota remain controversial according to previous studies. Recent studies using next-generation sequencing technology indicate that DM can alter the biodiversity and composition of oral microbiome especially subgingival microbiome. This may be another mechanism by which DM risks or aggravates periodontitis. Thus, to understand the role of oral microbiome in periodontitis of diabetics and the mechanism of shifts of oral microbiome under DM would be valuable for making specific therapeutic regimens for treating periodontitis patients with DM or preventing diabetic patients from periodontitis. This article reviews the role of oral microbiome in periodontal health (symbiosis) and disease (dysbiosis), highlights the oral microbial shifts under DM and summarizes the mechanism of the shifts.

RevDate: 2022-06-13

Bauer FM, Lärm L, Morandage S, et al (2022)

Development and Validation of a Deep Learning Based Automated Minirhizotron Image Analysis Pipeline.

Plant phenomics (Washington, D.C.), 2022:9758532.

Root systems of crops play a significant role in agroecosystems. The root system is essential for water and nutrient uptake, plant stability, symbiosis with microbes, and a good soil structure. Minirhizotrons have shown to be effective to noninvasively investigate the root system. Root traits, like root length, can therefore be obtained throughout the crop growing season. Analyzing datasets from minirhizotrons using common manual annotation methods, with conventional software tools, is time-consuming and labor-intensive. Therefore, an objective method for high-throughput image analysis that provides data for field root phenotyping is necessary. In this study, we developed a pipeline combining state-of-the-art software tools, using deep neural networks and automated feature extraction. This pipeline consists of two major components and was applied to large root image datasets from minirhizotrons. First, a segmentation by a neural network model, trained with a small image sample, is performed. Training and segmentation are done using "RootPainter." Then, an automated feature extraction from the segments is carried out by "RhizoVision Explorer." To validate the results of our automated analysis pipeline, a comparison of root length between manually annotated and automatically processed data was realized with more than 36,500 images. Mainly the results show a high correlation (r = 0.9) between manually and automatically determined root lengths. With respect to the processing time, our new pipeline outperforms manual annotation by 98.1-99.6%. Our pipeline, combining state-of-the-art software tools, significantly reduces the processing time for minirhizotron images. Thus, image analysis is no longer the bottle-neck in high-throughput phenotyping approaches.

RevDate: 2022-06-13

Wang J, Ma C, Ma S, et al (2022)

GmARP is Related to the Type III Effector NopAA to Promote Nodulation in Soybean (Glycine max).

Frontiers in genetics, 13:889795 pii:889795.

Type III effectors secreted by rhizobia regulate nodulation in the host plant and are important modulators of symbiosis between rhizobia and soybean (Glycine max), although the underlying mechanisms are poorly understood. Here, we studied the type III effector NopAA in Sinorhizobium fredii HH103, confirming its secretion into the extracellular environment under the action of genistein. The enzyme activity of NopAA was investigated in vitro, using xyloglucan and β-glucan as substrates. NopAA functions were investigated by the generation of a NopAA mutant and the effects of NopAA deficiency on symbiosis were analyzed. Soybean genes associated with NopAA were identified in a recombinant inbred line (RIL) population and their functions were verified. NopAA was confirmed to be a type III effector with glycosyl hydrolase activity, and its mutant did not promote nodulation. Quantitative trait locus (QTL) analysis identified 10 QTLs with one, Glyma.19g074200 (GmARP), found to be associated with NopAA and to positively regulate the establishment of symbiosis. All these results support the hypothesis that type III effectors interact with host proteins to regulate the establishment of symbiosis and suggest the possibility of manipulating the symbiotic soybean-rhizobia interaction to promote efficient nitrogen fixation.

RevDate: 2022-06-13
CmpDate: 2022-06-13

Uhlig F, NP Hyland (2022)

Making Sense of Quorum Sensing at the Intestinal Mucosal Interface.

Cells, 11(11): pii:cells11111734.

The gut microbiome can produce metabolic products that exert diverse activities, including effects on the host. Short chain fatty acids and amino acid derivatives have been the focus of many studies, but given the high microbial density in the gastrointestinal tract, other bacterial products such as those released as part of quorum sensing are likely to play an important role for health and disease. In this review, we provide of an overview on quorum sensing (QS) in the gastrointestinal tract and summarise what is known regarding the role of QS molecules such as auto-inducing peptides (AIP) and acyl-homoserine lactones (AHL) from commensal, probiotic, and pathogenic bacteria in intestinal health and disease. QS regulates the expression of numerous genes including biofilm formation, bacteriocin and toxin secretion, and metabolism. QS has also been shown to play an important role in the bacteria-host interaction. We conclude that the mechanisms of action of QS at the intestinal neuro-immune interface need to be further investigated.

RevDate: 2022-06-13
CmpDate: 2022-06-13

Nepel M, Pfeifer J, Oberhauser FB, et al (2022)

Nitrogen fixation by diverse diazotrophic communities can support population growth of arboreal ants.

BMC biology, 20(1):135.

BACKGROUND: Symbiotic ant-plant associations, in which ants live on plants, feed on plant-provided food, and protect host trees against threats, are ubiquitous across the tropics, with the Azteca-Cecropia associations being amongst the most widespread interactions in the Neotropics. Upon colonization of Cecropia's hollow internodes, Azteca queens form small patches with plant parenchyma, which are then used as waste piles when the colony grows. Patches-found in many ant-plant mutualisms-are present throughout the colony life cycle and may supplement larval food. Despite their initial nitrogen (N)-poor substrate, patches in Cecropia accommodate fungi, nematodes, and bacteria. In this study, we investigated the atmospheric N2 fixation as an N source in patches of early and established ant colonies.

RESULTS: Via 15N2 tracer assays, N2 fixation was frequently detected in all investigated patch types formed by three Azteca ant species. Quantified fixation rates were similar in early and established ant colonies and higher than in various tropical habitats. Based on amplicon sequencing, the identified microbial functional guild-the diazotrophs-harboring and transcribing the dinitrogenase reductase (nifH) gene was highly diverse and heterogeneous across Azteca colonies. The community composition differed between early and established ant colonies and partly between the ant species.

CONCLUSIONS: Our data show that N2 fixation can result in reasonable amounts of N in ant colonies, which might not only enable bacterial, fungal, and nematode growth in the patch ecosystems but according to our calculations can even support the growth of ant populations. The diverse and heterogeneous diazotrophic community implies a functional redundancy, which could provide the ant-plant-patch system with a higher resilience towards changing environmental conditions. Hence, we propose that N2 fixation represents a previously unknown potential to overcome N limitations in arboreal ant colonies.

RevDate: 2022-06-13
CmpDate: 2022-06-13

Abbas A, JP Zackular (2022)

Won't you be my neighbor? The importance of biogeography and nutrient niches in the gut.

Cell host & microbe, 30(6):759-761.

In the complex gastrointestinal tract landscape, competition for resources is fierce among microbes. One way to avoid conflict is migration to a different microhabitat. In this issue of Cell Host & Microbe, Liou et al. demonstrate how a commensal and pathogen differ in how and where they acquire nitrate.

RevDate: 2022-06-13
CmpDate: 2022-06-13

Zhao Y, Cartabia A, Lalaymia I, et al (2022)

Arbuscular mycorrhizal fungi and production of secondary metabolites in medicinal plants.

Mycorrhiza, 32(3-4):221-256.

Medicinal plants are an important source of therapeutic compounds used in the treatment of many diseases since ancient times. Interestingly, they form associations with numerous microorganisms developing as endophytes or symbionts in different parts of the plants. Within the soil, arbuscular mycorrhizal fungi (AMF) are the most prevalent symbiotic microorganisms forming associations with more than 70% of vascular plants. In the last decade, a number of studies have reported the positive effects of AMF on improving the production and accumulation of important active compounds in medicinal plants.In this work, we reviewed the literature on the effects of AMF on the production of secondary metabolites in medicinal plants. The major findings are as follows: AMF impact the production of secondary metabolites either directly by increasing plant biomass or indirectly by stimulating secondary metabolite biosynthetic pathways. The magnitude of the impact differs depending on the plant genotype, the AMF strain, and the environmental context (e.g., light, time of harvesting). Different methods of cultivation are used for the production of secondary metabolites by medicinal plants (e.g., greenhouse, aeroponics, hydroponics, in vitro and hairy root cultures) which also are compatible with AMF. In conclusion, the inoculation of medicinal plants with AMF is a real avenue for increasing the quantity and quality of secondary metabolites of pharmacological, medical, and cosmetic interest.

RevDate: 2022-06-13
CmpDate: 2022-06-13

Cope KR, Kafle A, Yakha JK, et al (2022)

Physiological and transcriptomic response of Medicago truncatula to colonization by high- or low-benefit arbuscular mycorrhizal fungi.

Mycorrhiza, 32(3-4):281-303.

Arbuscular mycorrhizal (AM) fungi form a root endosymbiosis with many agronomically important crop species. They enhance the ability of their host to obtain nutrients from the soil and increase the tolerance to biotic and abiotic stressors. However, AM fungal species can differ in the benefits they provide to their host plants. Here, we examined the putative molecular mechanisms involved in the regulation of the physiological response of Medicago truncatula to colonization by Rhizophagus irregularis or Glomus aggregatum, which have previously been characterized as high- and low-benefit AM fungal species, respectively. Colonization with R. irregularis led to greater growth and nutrient uptake than colonization with G. aggregatum. These benefits were linked to an elevated expression in the roots of strigolactone biosynthesis genes (NSP1, NSP2, CCD7, and MAX1a), mycorrhiza-induced phosphate (PT8), ammonium (AMT2;3), and nitrate (NPF4.12) transporters and the putative ammonium transporter NIP1;5. R. irregularis also stimulated the expression of photosynthesis-related genes in the shoot and the upregulation of the sugar transporters SWEET1.2, SWEET3.3, and SWEET 12 and the lipid biosynthesis gene RAM2 in the roots. In contrast, G. aggregatum induced the expression of biotic stress defense response genes in the shoots, and several genes associated with abiotic stress in the roots. This suggests that either the host perceives colonization by G. aggregatum as pathogen attack or that G. aggregatum can prime host defense responses. Our findings highlight molecular mechanisms that host plants may use to regulate their association with high- and low-benefit arbuscular mycorrhizal symbionts.

RevDate: 2022-06-13
CmpDate: 2022-06-13

Feller B, Dančák M, Hroneš M, et al (2022)

Mycorrhizal structures in mycoheterotrophic Thismia spp. (Thismiaceae): functional and evolutionary interpretations.

Mycorrhiza, 32(3-4):269-280.

Achlorophyllous, mycoheterotrophic plants often have an elaborate mycorrhizal colonization pattern, allowing a sustained benefit from external fungal root penetrations. The present study reveals the root anatomy and mycorrhizal pattern of eight mycoheterotrophic Thismia spp. (Thismiaceae), all of which show separate tissue compartments segregating different hyphal shapes of the mycorrhizal colonization, as there are intact straight, coiled and peculiarly knotted hyphae as well as degenerated clumps of hyphal material. Those tissue compartments in Thismia roots potentially comprise exo-, meso- and endoepidermae, and exo-, meso- and endocortices, although not all species develop all these root layers. Differences in details among species according to anatomy (number of root layers, cell sizes and shapes) and colonization pattern (hyphal shapes within cells) are striking and can be discussed as an evolutionary series towards increasing mycorrhizal complexity which roughly parallels the recently established phylogeny of Thismia. We suggest functional explanations for why the distinct elements of the associations can contribute to the mycorrhizal advantage for the plants and, thus, we emphasize the relevance of structural traits for mycorrhizae.

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ESP Quick Facts

ESP Origins

In the early 1990's, Robert Robbins was a faculty member at Johns Hopkins, where he directed the informatics core of GDB — the human gene-mapping database of the international human genome project. To share papers with colleagues around the world, he set up a small paper-sharing section on his personal web page. This small project evolved into The Electronic Scholarly Publishing Project.

ESP Support

In 1995, Robbins became the VP/IT of the Fred Hutchinson Cancer Research Center in Seattle, WA. Soon after arriving in Seattle, Robbins secured funding, through the ELSI component of the US Human Genome Project, to create the original ESP.ORG web site, with the formal goal of providing free, world-wide access to the literature of classical genetics.

ESP Rationale

Although the methods of molecular biology can seem almost magical to the uninitiated, the original techniques of classical genetics are readily appreciated by one and all: cross individuals that differ in some inherited trait, collect all of the progeny, score their attributes, and propose mechanisms to explain the patterns of inheritance observed.

ESP Goal

In reading the early works of classical genetics, one is drawn, almost inexorably, into ever more complex models, until molecular explanations begin to seem both necessary and natural. At that point, the tools for understanding genome research are at hand. Assisting readers reach this point was the original goal of The Electronic Scholarly Publishing Project.

ESP Usage

Usage of the site grew rapidly and has remained high. Faculty began to use the site for their assigned readings. Other on-line publishers, ranging from The New York Times to Nature referenced ESP materials in their own publications. Nobel laureates (e.g., Joshua Lederberg) regularly used the site and even wrote to suggest changes and improvements.

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When the site began, no journals were making their early content available in digital format. As a result, ESP was obliged to digitize classic literature before it could be made available. For many important papers — such as Mendel's original paper or the first genetic map — ESP had to produce entirely new typeset versions of the works, if they were to be available in a high-quality format.

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Early support from the DOE component of the Human Genome Project was critically important for getting the ESP project on a firm foundation. Since that funding ended (nearly 20 years ago), the project has been operated as a purely volunteer effort. Anyone wishing to assist in these efforts should send an email to Robbins.

ESP Plans

With the development of methods for adding typeset side notes to PDF files, the ESP project now plans to add annotated versions of some classical papers to its holdings. We also plan to add new reference and pedagogical material. We have already started providing regularly updated, comprehensive bibliographies to the ESP.ORG site.

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Papers in Classical Genetics

The ESP began as an effort to share a handful of key papers from the early days of classical genetics. Now the collection has grown to include hundreds of papers, in full-text format.

Digital Books

Along with papers on classical genetics, ESP offers a collection of full-text digital books, including many works by Darwin (and even a collection of poetry — Chicago Poems by Carl Sandburg).

Timelines

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Biographies

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Selected Bibliographies

Bibliographies on several topics of potential interest to the ESP community are now being automatically maintained and generated on the ESP site.

ESP Picks from Around the Web (updated 07 JUL 2018 )