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Bibliography on: Archaea

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ESP: PubMed Auto Bibliography 26 Sep 2023 at 01:30 Created: 


In 1977, Carl Woese and George Fox applied molecular techniques to biodiversity and discovered that life on Earth consisted of three, not two (prokaryotes and eukaryotes), major lineages, tracing back nearly to the very origin of life on Earth. The third lineage has come to be known as the Archaea. Organisms now considered Archaea were originally thought to be a kind of prokaryote, but Woese and Fox showed that they were as different from prokaryotes as they were from eukaryotes. To understand life on Earth one must also understand the Archaea .

Created with PubMed® Query: ( archaea[TITLE] OR archaebacteria[TITLE] ) NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)


RevDate: 2023-09-25

Murali R, Yu H, Speth DR, et al (2023)

Physiological potential and evolutionary trajectories of syntrophic sulfate-reducing bacterial partners of anaerobic methanotrophic archaea.

PLoS biology, 21(9):e3002292 pii:PBIOLOGY-D-22-02613 [Epub ahead of print].

Sulfate-coupled anaerobic oxidation of methane (AOM) is performed by multicellular consortia of anaerobic methanotrophic (ANME) archaea in obligate syntrophic partnership with sulfate-reducing bacteria (SRB). Diverse ANME and SRB clades co-associate but the physiological basis for their adaptation and diversification is not well understood. In this work, we used comparative metagenomics and phylogenetics to investigate the metabolic adaptation among the 4 main syntrophic SRB clades (HotSeep-1, Seep-SRB2, Seep-SRB1a, and Seep-SRB1g) and identified features associated with their syntrophic lifestyle that distinguish them from their non-syntrophic evolutionary neighbors in the phylum Desulfobacterota. We show that the protein complexes involved in direct interspecies electron transfer (DIET) from ANME to the SRB outer membrane are conserved between the syntrophic lineages. In contrast, the proteins involved in electron transfer within the SRB inner membrane differ between clades, indicative of convergent evolution in the adaptation to a syntrophic lifestyle. Our analysis suggests that in most cases, this adaptation likely occurred after the acquisition of the DIET complexes in an ancestral clade and involve horizontal gene transfers within pathways for electron transfer (CbcBA) and biofilm formation (Pel). We also provide evidence for unique adaptations within syntrophic SRB clades, which vary depending on the archaeal partner. Among the most widespread syntrophic SRB, Seep-SRB1a, subclades that specifically partner ANME-2a are missing the cobalamin synthesis pathway, suggestive of nutritional dependency on its partner, while closely related Seep-SRB1a partners of ANME-2c lack nutritional auxotrophies. Our work provides insight into the features associated with DIET-based syntrophy and the adaptation of SRB towards it.

RevDate: 2023-09-22
CmpDate: 2023-09-22

Tan S, Cheng M, Li XX, et al (2023)

Natronosalvus halobius gen. nov., sp. nov., Natronosalvus caseinilyticus sp. nov., Natronosalvus vescus sp. nov., Natronosalvus rutilus sp. nov. and Natronosalvus amylolyticus sp. nov., halophilic archaea isolated from salt lakes and soda lakes.

International journal of systematic and evolutionary microbiology, 73(9):.

Five halophilic archaeal strains (AGai3-5[T], KZCA101[T], CGA3[T], WLHS1[T] and WLHSJ1[T]) were isolated from salt lakes and soda lakes in PR China. These strains had low 16S rRNA gene similarities (91.3-96.0 %) to closely related species of the family Natrialbaceae and may represent a new genus of the family. Phylogenetic and phylogenomic analyses revealed that these strains formed a distinct clade, separate from the nearby genera Natronobiforma and Saliphagus. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity (AAI) values among these five strains and the current members of the family Natrialbaceae were 72-90, 20-42 and 62-91 %, respectively, clearly below the threshold values for species demarcation. According to the critical value of AAI (≤76 %) proposed to differentiate genera within the family Natrialbaceae, it was further indicated that these strains represented a novel genus within the family. These strains could be distinguished from the related genera according to differential phenotypic characteristics. The major lipids of these strains were phosphatidic acid (PA), phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, mannosyl glucosyl diether (DGD-PA), sulphated DGD-1 (S-DGD-PA) and sulphated galactosyl mannosyl glucosyl diether. The phenotypic, chemotaxonomic, phylogenetic and phylogenomic features indicated that strains AGai3-5[T] (=CGMCC 1.16078[T]=JCM 33549[T]), KZCA101[T] (=CGMCC 1.17431[T]=JCM 35074[T]), CGA3[T] (=CGMCC 1.17463[T]=JCM 34318[T]), WLHS1[T] (=CGMCC 1.13780[T]=JCM 33562[T]) and WLHSJ1[T] (=CGMCC 1.13784[T]=JCM 33563[T]) represent five novel species of a new genus within the family Natrialbaceae, named Natronosalvus halobius gen. nov., sp. nov., Natronosalvus caseinilyticus sp. nov., Natronosalvus vescus sp. nov., Natronosalvus rutilus sp. nov. and Natronosalvus amylolyticus sp. nov., respectively.

RevDate: 2023-09-20

Volmer JG, McRae H, M Morrison (2023)

The evolving role of methanogenic archaea in mammalian microbiomes.

Frontiers in microbiology, 14:1268451.

Methanogenic archaea (methanogens) represent a diverse group of microorganisms that inhabit various environmental and host-associated microbiomes. These organisms play an essential role in global carbon cycling given their ability to produce methane, a potent greenhouse gas, as a by-product of their energy production. Recent advances in culture-independent and -dependent studies have highlighted an increased prevalence of methanogens in the host-associated microbiome of diverse animal species. Moreover, there is increasing evidence that methanogens, and/or the methane they produce, may play a substantial role in human health and disease. This review addresses the expanding host-range and the emerging view of host-specific adaptations in methanogen biology and ecology, and the implications for host health and disease.

RevDate: 2023-09-16

Soza-Bolaños AI, Domínguez-Pérez RA, Ayala-Herrera JL, et al (2023)

Presence of methanogenic archaea in necrotic root canals of patients with or without type 2 diabetes mellitus.

Australian endodontic journal : the journal of the Australian Society of Endodontology Inc [Epub ahead of print].

Theoretically, a necrotic root canal fulfils all requirements as a niche for methanogens to inhabit. However, their presence in it and its implication in apical periodontitis (AP) is controversial. Therefore, to contribute to ending the controversy, this study aimed to detect and compare methanogens' presence in two distinct niches with supposedly different microenvironments; both were necrotic root canals associated with AP but one from patients with type 2 diabetes mellitus (T2DM) while the other from non-diabetic patients. A clinical examination was performed on 65 T2DM patients and 73 non-diabetic controls. Samples from necrotic root canals were obtained, and methanogens were identified. The presence of methanogens was three times higher (27.6%) in the T2DM group than in non-diabetic patients (8.2%). In addition, methanogens' presence was associated with a higher prevalence of periapical symptoms.

RevDate: 2023-09-15

Wang W, Lei J, Li M, et al (2023)

Archaea are better adapted to antimony stress than their bacterial counterparts in Xikuangshan groundwater.

The Science of the total environment pii:S0048-9697(23)05624-3 [Epub ahead of print].

Archaea are important ecological components of microbial communities in various environments, but are currently poorly investigated in antimony (Sb) contaminated groundwater particularly on their ecological differences in comparison with bacteria. To address this issue, groundwater samples were collected from Xikuangshan aquifer along an Sb gradient and subjected to 16S rRNA gene amplicon sequencing and bioinformatic analysis. The results demonstrated that bacterial communities were more susceptibly affected by elevated Sb concentration than their archaeal counterparts, and the positive stimulation of Sb concentration on bacterial diversity coincided with the intermediate disturbance hypothesis. Overall, the balance of environmental variables (Sb, pH, and EC), competitive interactions, and stochastic events jointly regulated bacterial and archaeal communities. Linear fitting analysis revealed that Sb significantly drove the deterministic process (heterogeneous selection) of bacterial communities, whereas stochastic process (dispersal limitation) contributed more to archaeal community assembly. In contract, the assembly of Sb-resistant bacteria and archaea was dominated by the stochastic process (undominated), which implied the important role of diversification and drift instead of selection. Compared with Sb-resistant microorganisms, bacterial and archaeal communities showed lower niche width, which may result from the constraints of Sb concentration and competitive interaction. Moreover, Sb-resistant archaea had a higher niche than that of Sb-resistant bacteria via investing on flexible metabolic pathways such as organic metabolism, ammonia oxidation; and carbon fixation to enhance their competitiveness. Our results offered new insights into the ecological adaptation mechanisms of bacteria and archaea in Sb-contaminated groundwater.

RevDate: 2023-09-15
CmpDate: 2023-09-15

Deore KS, Dhakephalkar PK, SS Dagar (2023)

Phylogenetically and physiologically diverse methanogenic archaea inhabit the Indian hot spring environments.

Archives of microbiology, 205(10):332.

Mesophilic and thermophilic methanogens belonging to the hydrogenotrophic, methylotrophic, and acetotrophic groups were isolated from Indian hot spring environments using BY and BCYT growth media. Following initial Hinf I-based PCR-RFLP screening, 70 methanogens were sequenced to ascertain their identity. These methanogens were phylogenetically and physiologically diverse and represented different taxa distributed across three physiological groups, i.e., hydrogenotrophs (53), methylotrophs (14) and acetotrophs (3). Overall, methanogens representing three families, five genera, and ten species, including two putative novel species, were recognized. The highest number and diversity of methanogens was observed at 40 ℃, dominated by Methanobacterium (10; 3 species), Methanosarcina (9; 3 species), Methanothermobacter (7; 2 species), Methanomethylovorans (5; 1 species) and Methanoculleus (3; 1 species). Both putative novel methanogen species were isolated at 40 ℃ and belonged to the genera Methanosarcina and Methanobacterium. At 55 ℃, limited diversity was observed, and resulted in the isolation of only two genera of methanogens, i.e., Methanothermobacter (28; 2 species) and Methanosarcina (4; 1 species). At 70 ℃, only members of the genus Methanothermobacter (5; 2 species) were isolated, whereas no methanogen could be cultured at 85 ℃. Ours is the first study that documents the extensive range of cultivable methanogenic archaea inhabiting hot springs across various geothermal provinces of India.

RevDate: 2023-09-13

Zou D, Chen J, Zhang C, et al (2023)

Diversity and salinity adaptations of ammonia oxidizing archaea in three estuaries of China.

Applied microbiology and biotechnology [Epub ahead of print].

Ammonia-oxidizing archaea (AOA) are ubiquitously found in diverse habitats and play pivotal roles in the nitrogen and carbon cycle, especially in estuarine and coastal environments. Despite the fact that the diversity and distribution of AOA are thought to be tightly linked to habitats, little is known about the relationship that underpins their genomic traits, adaptive potentials, and ecological niches. Here, we have characterized and compared the AOA community in three estuaries of China using metagenomics. AOA were the dominant ammonia oxidizers in the three estuaries. Through phylogenetic analyses, five major AOA groups were identified, including the Nitrosomarinus-like, Nitrosopumilus-like, Aestuariumsis-like, Nitrosarchaeum-like, and Nitrosopelagicus-like groups. Statistical analyses showed that the aquatic and sedimentary AOA communities were mainly influenced by spatial factors (latitude and water depth) and environmental factors (salinity, pH, and dissolved oxygen) in estuaries, respectively. Compared to AOA dwelling in terrestrial and marine habitats, estuarine AOA encoded more genes involved in glucose and amino acid metabolism, transport systems, osmotic control, and cell motility. The low proteome isoelectric points (pI), high content of acidic amino acids, and the presence of potassium ion and mechanosensitive channels suggest a "salt-in" strategy for estuarine AOA to counteract high osmolarity in their surroundings. Our findings have indicated potential adaptation strategies and highlighted their importance in the estuarine nitrogen and carbon cycles. KEY POINTS: • Spatial and environmental factors influence water and sediment AOA respectively. • Estuarine AOA share low proteome isoelectric value and high acid amino acids content. • AOA adaptation to estuaries is likely resulted from their unique genomic features.

RevDate: 2023-09-12

Spang A (2023)

Uncovering the hidden world of nanosized archaea.

Nature reviews. Microbiology, 21(10):638.

RevDate: 2023-09-12

Oudova-Rivera B, Crombie AT, Murrell JC, et al (2023)

Alcohols as inhibitors of ammonia oxidising archaea and bacteria.

FEMS microbiology letters pii:7271388 [Epub ahead of print].

Ammonia oxidisers are key players in the global nitrogen cycle, and are responsible for the oxidation of ammonia to nitrite, which is further oxidised to nitrate by other microorganisms. Their activity can lead to adverse effects on some human-impacted environments, including water pollution through leaching of nitrate and emissions of the greenhouse gas nitrous oxide (N2O). Ammonia monooxygenase (AMO) is the key enzyme in microbial ammonia oxidation and shared by all groups of aerobic ammonia oxidisers. The AMO has not been purified in an active form, and much of what is known about its potential structure and function comes from studies on its interactions with inhibitors. The archaeal AMO is less well studied as ammonia oxidising archaea were discovered much more recently than their bacterial counterparts. The inhibition of ammonia oxidation by aliphatic alcohols (C1-C8) using the model terrestrial ammonia oxidising archaeon 'Candidatus Nitrosocosmicus franklandus' C13 and the ammonia oxidising bacterium Nitrosomonas europaea was examined in order to expand knowledge about the range of inhibitors of ammonia oxidisers. Methanol was the most potent specific inhibitor of the AMO in both ammonia oxidisers, with half-maximal inhibitory concentrations (IC50) of 0.19 mM and 0.31 mM, respectively. The inhibition was AMO-specific in 'Ca. N. franklandus' C13 in the presence of C1-C2 alcohols, and in N. europaea in the presence of C1-C3 alcohols. Higher chain-length alcohols caused non-specific inhibition and also inhibited hydroxylamine oxidation. Ethanol was tolerated by 'Ca. N. franklandus' C13 at a higher threshold concentration than other chain-length alcohols, with 80 mM ethanol being required for complete inhibition of ammonia oxidation.

RevDate: 2023-09-06
CmpDate: 2023-09-06

Vipindas PV, Jabir T, Venkatachalam S, et al (2023)

Vertical segregation and phylogenetic characterization of archaea and archaeal ammonia monooxygenase gene in the water column of the western Arctic Ocean.

Extremophiles : life under extreme conditions, 27(3):24.

Archaea constitute a substantial fraction of marine microbial biomass and play critical roles in the biogeochemistry of oceans. However, studies on their distribution and ecology in the Arctic Ocean are relatively scarce. Here, we studied the distributions of archaea and archaeal ammonia monooxygenase (amoA) gene in the western Arctic Ocean, using the amplicon sequencing approach from the sea surface to deep waters up to 3040 m depth. A total of five archaeal phyla, Nitrososphaerota, "Euryarchaeota", "Halobacteriota," "Nanoarchaeota", and Candidatus Thermoplasmatota, were detected. We observed a clear, depth-dependent vertical segregation among archaeal communities. Ca. Thermoplasmatota (66.8%) was the most dominant phylum in the surface waters. At the same time, Nitrososphaerota (55.9%) was dominant in the deep waters. Most of the amoA gene OTUs (99%) belonged to the Nitrosopumilales and were further clustered into five subclades ("NP-Alpha", "NP-Delta", "NP-Epsilon", "NP-Gamma", and "NP-Theta"). "NP-Epsilon" was the most dominant clade throughout the water column and "NP_Alpha" showed higher abundance only in the deeper water. Salinity and inorganic nutrient concentrations were the major factors that determined the vertical segregation of archaea. We anticipate that the observed differences in the vertical distribution of archaea might contribute to the compartmentalization of dark carbon fixation and nitrification in deeper water and organic matter degradation in surface waters of the Arctic Ocean.

RevDate: 2023-08-31

Di Giulio M (2023)

The absence of the evolutionary state of the Prokaryote would imply a polyphyletic origin of proteins and that LUCA, the ancestor of bacteria and that of archaea were progenotes.

Bio Systems pii:S0303-2647(23)00189-2 [Epub ahead of print].

I analysed the similarity gradient observed in protein families - of phylogenetically deep fundamental traits - of bacteria and archaea, ranging from cases such as the core of the DNA replication apparatus where there is no sequence similarity between the proteins involved, to cases in which, as in the translation initiation factors, only some proteins involved would be homologs, to cases such as for aminoacyl-tRNA synthetases in which most of the proteins involved would be homologs. This pattern of similarity between bacteria and archaea would seem to be a very clear indication of a transitional evolutionary stage that preceded both the Last Bacterial Common Ancestor and the Last Archaeal Common Ancestor, i.e. progenotic stages. Indeed, this similarity pattern would seem to exemplify an ongoing transition as all the evolutionary phases would be represented in it. Instead, in the cellular stage it is expected that these evolutionary phases should have already been overcome, i.e. completed, and therefore no longer detectable. In fact, if we had really been in the presence of the prokaryotic stage then we should not have observed this similarity pattern in proteins involved in defining the ancestral characters of bacteria and archaea, as the completion of the different cellular structures should have required a very low number of proteins to be late evolved in lineages leading to bacteria and archaea. Indeed, the already reached state of the Prokaryote would have determined complete cellular structures therefore a total absence of proteins to evolve independently in the two main phyletic lineages and able to complete the evolution of a particular character already evidently in a definitive state, which, on the other hand, does not appear to have been the case. All this would have prevented the formation of this pattern of similarity which instead would appear to be real. In conclusion, the existence of this pattern of similarity observed in the families of homologous proteins of bacteria and archaea would imply the absence of the evolutionary stage of the Prokaryote and consequently a progenotic status to be assigned to the LUCA. Indeed, the LUCA stage would have been a stage of evolutionary transition because it is belatedly marked by the presence of all the different evolutionary phases, evidently more easily interpretable within the definition of progenote than that of genote precisely because they are inherent in an evolutionary transition and not to an evolution that has already been achieved. Finally, I discuss the importance of these arguments for the polyphyletic origin of proteins.

RevDate: 2023-08-29

Xie L, Yu S, Lu X, et al (2023)

Different Responses of Bacteria and Archaea to Environmental Variables in Brines of the Mahai Potash Mine, Qinghai-Tibet Plateau.

Microorganisms, 11(8):.

Salt mines feature both autochthonous and allochthonous microbial communities introduced by industrialization. It is important to generate the information on the diversity of the microbial communities present in the salt mines and how they are shaped by the environment representing ecological diversification. Brine from Mahai potash mine (Qianghai, China), an extreme hypersaline environment, is used to produce potash salts for hundreds of millions of people. However, halophiles preserved in this niche during deposition are still unknown. In this study, using high-throughput 16S rRNA gene amplicon sequencing and estimation of physicochemical variables, we examined brine samples collected from locations with the gradient of industrial activity intensity and discrete hydrochemical compositions in the Mahai potash mine. Our findings revealed a highly diverse bacterial community, mainly composed of Pseudomonadota in the hypersaline brines from the industrial area, whereas in the natural brine collected from the upstream Mahai salt lake, most of the 16S rRNA gene reads were assigned to Bacteroidota. Halobacteria and halophilic methanogens dominated archaeal populations. Furthermore, we discovered that in the Mahai potash mining area, bacterial communities tended to respond to anthropogenic influences. In contrast, archaeal diversity and compositions were primarily shaped by the chemical properties of the hypersaline brines. Conspicuously, distinct methanogenic communities were discovered in sets of samples with varying ionic compositions, indicating their strong sensitivity to the brine hydrochemical alterations. Our findings provide the first taxonomic snapshot of microbial communities from the Mahai potash mine and reveal the different responses of bacteria and archaea to environmental variations in this high-altitude aquatic ecosystem.

RevDate: 2023-08-26

Garcia-Bonete MJ, Rajan A, Suriano F, et al (2023)

The Underrated Gut Microbiota Helminths, Bacteriophages, Fungi, and Archaea.

Life (Basel, Switzerland), 13(8): pii:life13081765.

The microbiota inhabits the gastrointestinal tract, providing essential capacities to the host. The microbiota is a crucial factor in intestinal health and regulates intestinal physiology. However, microbiota disturbances, named dysbiosis, can disrupt intestinal homeostasis, leading to the development of diseases. Classically, the microbiota has been referred to as bacteria, though other organisms form this complex group, including viruses, archaea, and eukaryotes such as fungi and protozoa. This review aims to clarify the role of helminths, bacteriophages, fungi, and archaea in intestinal homeostasis and diseases, their interaction with bacteria, and their use as therapeutic targets in intestinal maladies.

RevDate: 2023-08-12

Naitam MG, Ramakrishnan B, Grover M, et al (2023)

Rhizosphere-dwelling halophilic archaea: a potential candidate for alleviating salinity-associated stress in agriculture.

Frontiers in microbiology, 14:1212349.

Salinity is a serious environmental factor that impedes crop growth and drastically reduces yield. This study aimed to investigate the potential of halophilic archaea isolated from the Rann of Kutch to alleviate the negative impact of salinity on crop growth and yield. The halophilic archaea, which demonstrated high tolerance to salinity levels up to 4.5 M, were evaluated for their ability to promote plant growth in both salt-tolerant and salt-susceptible wheat cultivars. Our assessment focused on their capacity to solubilize essential nutrients, including phosphorus (14-61 mg L[-1]), potassium (37-78 mg L[-1]), and zinc (8-17 mg L[-1]), as well as their production of the phytohormone IAA (17.30 to 49.3 μg ml[-1]). To conduct the experiments, five wheat cultivars (two salt-tolerant and three salt-susceptible) were grown in triplicates using soft MS agar tubes (50 ml) and pots containing 10 kg of soil with an electrical conductivity (EC) of 8 dSm[-1]. Data were collected at specific time points: 21 days after sowing (DAS) for the MS agar experiment, 45 DAS for the pot experiment, and at the time of harvest. In the presence of haloarchaea, the inoculated treatments exhibited significant increases in total protein (46%), sugar (27%), and chlorophyll (31%) levels compared to the un-inoculated control. Furthermore, the inoculation led to an elevated accumulation of osmolyte proline (31.51%) and total carbohydrates (27.85%) while substantially reducing the activity of antioxidant enzymes such as SOD, catalase, and peroxidase by 57-76%, respectively. Notably, the inoculated treatments also showed improved plant vegetative growth parameters compared to the un-inoculated treatments. Interestingly, the positive effects of the halophilic archaea were more pronounced in the susceptible wheat cultivars than in the tolerant cultivars. These findings highlight the growth-promoting abilities of the halophilic archaeon Halolamina pelagica CDK2 and its potential to mitigate the detrimental effects of salinity. Consequently, further evaluation of this halophilic archaeon under field conditions is warranted to explore its potential use in the development of microbial inoculants.

RevDate: 2023-05-15
CmpDate: 2023-05-04

Taubner RS, Baumann LMF, Steiner M, et al (2023)

Lipidomics and Comparative Metabolite Excretion Analysis of Methanogenic Archaea Reveal Organism-Specific Adaptations to Varying Temperatures and Substrate Concentrations.

mSystems, 8(2):e0115922.

Methanogenic archaea possess diverse metabolic characteristics and are an ecologically and biotechnologically important group of anaerobic microorganisms. Although the scientific and biotechnological value of methanogens is evident with regard to their methane-producing physiology, little is known about their amino acid excretion, and virtually nothing is known about the lipidome at different substrate concentrations and temperatures on a quantitative comparative basis. Here, we present the lipidome and a comprehensive quantitative analysis of proteinogenic amino acid excretion as well as methane, water, and biomass production of the three autotrophic, hydrogenotrophic methanogens Methanothermobacter marburgensis, Methanothermococcus okinawensis, and Methanocaldococcus villosus under varying temperatures and nutrient supplies. The patterns and rates of production of excreted amino acids and the lipidome are unique for each tested methanogen and can be modulated by varying the incubation temperature and substrate concentration, respectively. Furthermore, the temperature had a significant influence on the lipidomes of the different archaea. The water production rate was much higher, as anticipated from the rate of methane production for all studied methanogens. Our results demonstrate the need for quantitative comparative physiological studies connecting intracellular and extracellular constraints of organisms to holistically investigate microbial responses to environmental conditions. IMPORTANCE Biological methane production by methanogenic archaea has been well studied for biotechnological purposes. This study reveals that methanogenic archaea actively modulate their lipid inventory and proteinogenic amino acid excretion pattern in response to environmental changes and the possible utilization of methanogenic archaea as microbial cell factories for the targeted production of lipids and amino acids.

RevDate: 2023-08-09

Ren B, Wang W, Shen L, et al (2023)

Nitrogen fertilization rate affects communities of ammonia-oxidizing archaea and bacteria in paddy soils across different climatic zones of China.

The Science of the total environment, 902:166089 pii:S0048-9697(23)04714-9 [Epub ahead of print].

Nitrogen fertilization has important effects on nitrification. However, how the rate of nitrogen fertilization affects nitrification potential, as well as the communities of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB), remains unclear. We performed a large-scale investigation of nitrification potential and ammonia-oxidizer communities in Chinese paddy fields at different nitrogen fertilization rates across different climatic zones. It was found that the nitrification potential at the high nitrogen fertilization rate (≥150 kg[-1] N ha[-1]) was 23.35 % higher than that at the intermediate rate (100-150 kg[-1] N ha[-1]) and 20.77 % higher than that at the low rate (< 100 kg[-1] N ha[-1]). The nitrification potential showed no significant variation among different nitrogen fertilization rates across climatic zones. Furthermore, the AOA and AOB amoA gene abundance at the high nitrogen fertilization rate was 481.67 % and 292.74 % higher (p < 0.05) than that at the intermediate rate, respectively. Correlation analysis demonstrated a significant positive correlation between AOB abundance and nitrification potential. AOA and AOB community composition differed significantly among nitrogen fertilization rates. Moreover, soil NH4[+] content, pH, water content, bulk density, and annual average temperature were regarded as key environmental factors influencing the community structure of ammonia-oxidizers. Taken together, the nitrogen fertilization rate had a significant impact on the communities of AOA and AOB but did not significantly alter the nitrification potential. Our findings provide new insights into the impact of nitrogen fertilization management on nitrification in rice paddy fields.

RevDate: 2023-07-29

Manfredini A, Malusà E, Pinzari F, et al (2023)

Quantification of nitrogen cycle functional genes from viable archaea and bacteria in paddy soil.

Journal of applied microbiology pii:7233727 [Epub ahead of print].

AIMS: One of the main challenges of culture-independent soil microbiology is distinguishing the microbial community's viable fraction from dead matter. Propidium monoazide (PMA) binds the DNA of dead cells, preventing its amplification. This dye could represent a robust means to overcome the drawbacks of other selective methods, such as RNA-based analyses.

METHODS AND RESULTS: We quantified functional genes from viable archaea and bacteria in soil by combining the use of PMA and qPCR. Four N-cycle-related functional genes (bacterial and archaeal ammonia monooxygenase, nitrate reductase and nitrite reductase) were successfully quantified from the living fraction of bacteria and archaea of a paddy soil. The protocol was also tested with pure bacterial cultures and soils with different physical and chemical properties.

CONCLUSIONS: The experiment results revealed a contrasting impact of mineral and organic fertilizers on the abundance of microbial genes related to the N cycle in paddy soil.

RevDate: 2023-07-29

Marín-Paredes R, Bolívar-Torres HH, Coronel-Gaytán A, et al (2023)

A Metagenome from a Steam Vent in Los Azufres Geothermal Field Shows an Abundance of Thermoplasmatales archaea and Bacteria from the Phyla Actinomycetota and Pseudomonadota.

Current issues in molecular biology, 45(7):5849-5864.

Los Azufres National Park is a geothermal field that has a wide number of thermal manifestations; nevertheless, the microbial communities in many of these environments remain unknown. In this study, a metagenome from a sediment sample from Los Azufres National Park was sequenced. In this metagenome, we found that the microbial diversity corresponds to bacteria (Actinomycetota, Pseudomonadota), archaea (Thermoplasmatales and Candidatus Micrarchaeota and Candidatus Parvarchaeota), eukarya (Cyanidiaceae), and viruses (Fussellovirus and Caudoviricetes). The functional annotation showed genes related to the carbon fixation pathway, sulfur metabolism, genes involved in heat and cold shock, and heavy-metal resistance. From the sediment, it was possible to recover two metagenome-assembled genomes from Ferrimicrobium and Cuniculiplasma. Our results showed that there are a large number of microorganisms in Los Azufres that deserve to be studied.

RevDate: 2023-07-27

Esser SP, Rahlff J, Zhao W, et al (2023)

A predicted CRISPR-mediated symbiosis between uncultivated archaea.

Nature microbiology [Epub ahead of print].

CRISPR-Cas systems defend prokaryotic cells from invasive DNA of viruses, plasmids and other mobile genetic elements. Here, we show using metagenomics, metatranscriptomics and single-cell genomics that CRISPR systems of widespread, uncultivated archaea can also target chromosomal DNA of archaeal episymbionts of the DPANN superphylum. Using meta-omics datasets from Crystal Geyser and Horonobe Underground Research Laboratory, we find that CRISPR spacers of the hosts Candidatus Altiarchaeum crystalense and Ca. A. horonobense, respectively, match putative essential genes in their episymbionts' genomes of the genus Ca. Huberiarchaeum and that some of these spacers are expressed in situ. Metabolic interaction modelling also reveals complementation between host-episymbiont systems, on the basis of which we propose that episymbionts are either parasitic or mutualistic depending on the genotype of the host. By expanding our analysis to 7,012 archaeal genomes, we suggest that CRISPR-Cas targeting of genomes associated with symbiotic archaea evolved independently in various archaeal lineages.

RevDate: 2023-07-26

Cai Y, Li H, Qu G, et al (2023)

Responses of applied voltages on the archaea microbial distribution in sludge digestion.

Chemosphere pii:S0045-6535(23)01906-9 [Epub ahead of print].

As the development of urban population led to the increase of domestic water consumption, consequently the generation of surplus sludge (SS) produced increasingly during sewage treatment processes. In order to enhance the SS resource utilization efficiency, an electricity-assisted anaerobic digestion (EAAD) system was employed to examine the alterations in the digestion broth and the characteristics of gas production. Additionally, the response of applied voltages on the distribution of archaeal community near various electrodes within the sludge was explored. The results revealed that the application of high voltages exceeding 3.0 V hindered the CH4 production but stimulated the CO2 generation. Subsequently, both CH4 and CO2 production were impeded by the applied voltages. Furthermore, the increased voltages significantly decreased the abundance of Methanomicrobia, Methanosaeta, and Methanosarcina, which were crucial determinants of CH4 content in biogas. Notably, the excessively high voltages intensities caused the AD process to halt and even inactivate the microbial flora. Interestingly, the distribution characteristics of archaeal community were influenced not only by the voltages intensity but also exhibited variations between the anode and cathode regions. Moreover, as the applied voltage intensified, the discrepancy of responses between the cathode and anode regions became more pronounced, offering novel theoretical and technical foundations for the advancement of electricity-assisted with AD technology.

RevDate: 2023-07-25

Williams AM, Jolley E, Santiago-Martínez MG, et al (2023)

In vivo structure probing of RNA in Archaea: Novel insights into the ribosome structure of Methanosarcina acetivorans.

RNA (New York, N.Y.) pii:rna.079687.123 [Epub ahead of print].

Structure probing combined with next-generation sequencing (NGS) has provided novel insights into RNA structure-function relationships. To date such studies have focused largely on bacteria and eukaryotes, with little attention given to the third domain of life, archaea. Furthermore, functional RNAs have not been extensively studied in archaea, leaving open questions about RNA structure and function within this domain of life. With archaeal species being diverse and having many similarities to both bacteria and eukaryotes, the archaea domain has the potential to be an evolutionary bridge. In this study, we introduce a method for probing RNA structure in vivo in the archaea domain of life. We investigated the structure of ribosomal RNA (rRNA) from Methanosarcina acetivorans, a well-studied anaerobic archaeal species, grown with either methanol or acetate. After probing the RNA in vivo with dimethyl sulfate (DMS), Structure-seq2 libraries were generated, sequenced, and analyzed. We mapped the reactivity of DMS onto the secondary structure of the ribosome, which we determined independently with comparative analysis, and confirmed the accuracy of DMS probing in M. acetivorans Accessibility of the rRNA to DMS in the two carbon sources was found to be quite similar, although some differences were found. Overall, this study establishes the Structure-seq2 pipeline in the archaea domain of life and informs about ribosomal structure within M. acetivorans.

RevDate: 2023-07-24
CmpDate: 2023-07-24

Kim YB, Whon TW, Kim JY, et al (2023)

In-depth metataxonomic investigation reveals low richness, high intervariability, and diverse phylotype candidates of archaea in the human urogenital tract.

Scientific reports, 13(1):11746.

The urogenital microbiota is the potential principal factor in the pathophysiology of urinary tract infection and the protection of urinary tract health. Little is known about the urogenital archaeome although several reports have indicated that the archaeomes of various regions of the human body are associated with health. Accordingly, we aimed to determine the presence and diversity of archaeomes in the human urogenital tract. To explore the urogenital archaeome, voided urine specimens from 373 asymptomatic Korean individuals were used. No difference was observed in body mass index, age, or gender, according to presence of archaea. Analysis of archaeal 16S rRNA gene amplicons of archaea positive samples consisted of simple community structures, including diverse archaea, such as the phyla Methanobacteriota, Thermoproteota, and Halobacteriota. Asymptomatic individuals showed high participant-dependent intervariability in their urogenital archaeomes. The mean relative archaeal abundance was estimated to be 0.89%, and fluorescence in situ hybridisation micrographs provided evidence of archaeal cells in the human urogenital tract. In addition, the urogenital archaeome shared partial taxonomic compositional characteristics with those of the other body sites. In this study, Methanobacteriota, Thermoproteota, and Halobacteriota were suggested as inhabitants of the human urogenital tract, and a distinct human urogenital archaeome was characterised. These findings expand our knowledge of archaea-host associations in the human urogenital tract and may lead to novel insights into the role of archaea in urinary tract health.

RevDate: 2023-07-19

Banas I, Esser SP, Turzynski V, et al (2023)

Spatio-functional organization in virocells of small uncultivated archaea from the deep biosphere.

The ISME journal [Epub ahead of print].

Despite important ecological roles posited for virocells (i.e., cells infected with viruses), studying individual cells in situ is technically challenging. We introduce here a novel correlative microscopic approach to study the ecophysiology of virocells. By conducting concerted virusFISH, 16S rRNA FISH, and scanning electron microscopy interrogations of uncultivated archaea, we linked morphologies of various altiarchaeal cells to corresponding phylogenetic signals and indigenous virus infections. While uninfected cells exhibited moderate separation between fluorescence signals of ribosomes and DNA, virocells displayed complete cellular segregation of chromosomal DNA from viral DNA, the latter co-localizing with host ribosome signals. A similar spatial separation was observed in dividing cells, with viral signals congregating near ribosomes at the septum. These observations suggest that replication of these uncultivated viruses occurs alongside host ribosomes, which are used to generate the required proteins for virion assembly. Heavily infected cells sometimes displayed virus-like particles attached to their surface, which agree with virus structures in cells observed via transmission electron microscopy. Consequently, this approach is the first to link genomes of uncultivated viruses to their respective structures and host cells. Our findings shed new light on the complex ecophysiology of archaeal virocells in deep subsurface biofilms and provide a solid framework for future in situ studies of virocells.

RevDate: 2023-07-19

Bargiela R, Korzhenkov AA, McIntosh OA, et al (2023)

Evolutionary patterns of archaea predominant in acidic environment.

Environmental microbiome, 18(1):61.

BACKGROUND: Archaea of the order Thermoplasmatales are widely distributed in natural acidic areas and are amongst the most acidophilic prokaryotic organisms known so far. These organisms are difficult to culture, with currently only six genera validly published since the discovery of Thermoplasma acidophilum in 1970. Moreover, known great diversity of uncultured Thermoplasmatales represents microbial dark matter and underlines the necessity of efforts in cultivation and study of these archaea. Organisms from the order Thermoplasmatales affiliated with the so-called "alphabet-plasmas", and collectively dubbed "E-plasma", were the focus of this study. These archaea were found predominantly in the hyperacidic site PM4 of Parys Mountain, Wales, UK, making up to 58% of total metagenomic reads. However, these archaea escaped all cultivation attempts.

RESULTS: Their genome-based metabolism revealed its peptidolytic potential, in line with the physiology of the previously studied Thermoplasmatales isolates. Analyses of the genome and evolutionary history reconstruction have shown both the gain and loss of genes, that may have contributed to the success of the "E-plasma" in hyperacidic environment compared to their community neighbours. Notable genes among them are involved in the following molecular processes: signal transduction, stress response and glyoxylate shunt, as well as multiple copies of genes associated with various cellular functions; from energy production and conversion, replication, recombination, and repair, to cell wall/membrane/envelope biogenesis and archaella production. History events reconstruction shows that these genes, acquired by putative common ancestors, may determine the evolutionary and functional divergences of "E-plasma", which is much more developed than other representatives of the order Thermoplasmatales. In addition, the ancestral hereditary reconstruction strongly indicates the placement of Thermogymnomonas acidicola close to the root of the Thermoplasmatales.

CONCLUSIONS: This study has analysed the metagenome-assembled genome of "E-plasma", which denotes the basis of their predominance in Parys Mountain environmental microbiome, their global ubiquity, and points into the right direction of further cultivation attempts. The results suggest distinct evolutionary trajectories of organisms comprising the order Thermoplasmatales, which is important for the understanding of their evolution and lifestyle.

RevDate: 2023-07-17

Feehan B, Ran Q, Dorman V, et al (2023)

Novel complete methanogenic pathways in longitudinal genomic study of monogastric age-associated archaea.

Animal microbiome, 5(1):35.

BACKGROUND: Archaea perform critical roles in the microbiome system, including utilizing hydrogen to allow for enhanced microbiome member growth and influencing overall host health. With the majority of microbiome research focusing on bacteria, the functions of archaea are largely still under investigation. Understanding methanogenic functions during the host lifetime will add to the limited knowledge on archaeal influence on gut and host health. In our study, we determined lifelong archaea dynamics, including detection and methanogenic functions, while assessing global, temporal and host distribution of our novel archaeal metagenome-assembled genomes (MAGs). We followed 7 monogastric swine throughout their life, from birth to adult (1-156 days of age), and collected feces at 22 time points. The samples underwent gDNA extraction, Illumina sequencing, bioinformatic quality and assembly processes, MAG taxonomic assignment and functional annotation. MAGs were utilized in downstream phylogenetic analysis for global, temporal and host distribution in addition to methanogenic functional potential determination.

RESULTS: We generated 1130 non-redundant MAGs, representing 588 unique taxa at the species level, with 8 classified as methanogenic archaea. The taxonomic classifications were as follows: orders Methanomassiliicoccales (5) and Methanobacteriales (3); genera UBA71 (3), Methanomethylophilus (1), MX-02 (1), and Methanobrevibacter (3). We recovered the first US swine Methanobrevibacter UBA71 sp006954425 and Methanobrevibacter gottschalkii MAGs. The Methanobacteriales MAGs were identified primarily during the young, preweaned host whereas Methanomassiliicoccales primarily in the adult host. Moreover, we identified our methanogens in metagenomic sequences from Chinese swine, US adult humans, Mexican adult humans, Swedish adult humans, and paleontological humans, indicating that methanogens span different hosts, geography and time. We determined complete metabolic pathways for all three methanogenic pathways: hydrogenotrophic, methylotrophic, and acetoclastic. This study provided the first evidence of acetoclastic methanogenesis in archaea of monogastric hosts which indicated a previously unknown capability for acetate utilization in methanogenesis for monogastric methanogens. Overall, we hypothesized that the age-associated detection patterns were due to differential substrate availability via the host diet and microbial metabolism, and that these methanogenic functions are likely crucial to methanogens across hosts. This study provided a comprehensive, genome-centric investigation of monogastric-associated methanogens which will further improve our understanding of microbiome development and functions.

RevDate: 2023-07-14

Wright CL, LE Lehtovirta-Morley (2023)

Nitrification and beyond: metabolic versatility of ammonia oxidising archaea.

The ISME journal [Epub ahead of print].

Ammonia oxidising archaea are among the most abundant living organisms on Earth and key microbial players in the global nitrogen cycle. They carry out oxidation of ammonia to nitrite, and their activity is relevant for both food security and climate change. Since their discovery nearly 20 years ago, major insights have been gained into their nitrogen and carbon metabolism, growth preferences and their mechanisms of adaptation to the environment, as well as their diversity, abundance and activity in the environment. Despite significant strides forward through the cultivation of novel organisms and omics-based approaches, there are still many knowledge gaps on their metabolism and the mechanisms which enable them to adapt to the environment. Ammonia oxidising microorganisms are typically considered metabolically streamlined and highly specialised. Here we review the physiology of ammonia oxidising archaea, with focus on aspects of metabolic versatility and regulation, and discuss these traits in the context of nitrifier ecology.

RevDate: 2023-07-14

Padilla-Vaca F, de la Mora J, García-Contreras R, et al (2023)

Two-Component System Sensor Kinases from Asgardian Archaea May Be Witnesses to Eukaryotic Cell Evolution.

Molecules (Basel, Switzerland), 28(13):.

The signal transduction paradigm in bacteria involves two-component systems (TCSs). Asgardarchaeota are archaea that may have originated the current eukaryotic lifeforms. Most research on these archaea has focused on eukaryotic-like features, such as genes involved in phagocytosis, cytoskeleton structure, and vesicle trafficking. However, little attention has been given to specific prokaryotic features. Here, the sequence and predicted structural features of TCS sensor kinases analyzed from two metagenome assemblies and a genomic assembly from cultured Asgardian archaea are presented. The homology of the sensor kinases suggests the grouping of Lokiarchaeum closer to bacterial homologs. In contrast, one group from a Lokiarchaeum and a meta-genome assembly from Candidatus Heimdallarchaeum suggest the presence of a set of kinases separated from the typical bacterial TCS sensor kinases. AtoS and ArcB homologs were found in meta-genome assemblies along with defined domains for other well-characterized sensor kinases, suggesting the close link between these organisms and bacteria that may have resulted in the metabolic link to the establishment of symbiosis. Several kinases are predicted to be cytoplasmic; some contain several PAS domains. The data shown here suggest that TCS kinases in Asgardian bacteria are witnesses to the transition from bacteria to eukaryotic organisms.

RevDate: 2023-07-10

Sun J, Zhang A, Zhang Z, et al (2023)

Distinct assembly processes and environmental adaptation of abundant and rare archaea in Arctic marine sediments.

Marine environmental research, 190:106082 pii:S0141-1136(23)00210-6 [Epub ahead of print].

Revealing the ecological processes and environmental adaptation of abundant and rare archaea is a central, but poorly understood, topic in ecology. Here, abundant and rare archaeal diversity, community assembly processes and co-occurrence patterns were comparatively analyzed in Arctic marine sediments. Our findings revealed that the rare taxa exhibited significantly higher diversity compared to the abundant taxa. Additionally, the abundant taxa displayed stronger environmental adaptation than the rare taxa. The co-occurrence network analysis demonstrated that the rare taxa developed more interspecies interactions and modules in response to environmental disturbance. Furthermore, the community assembly of abundant and rare taxa in sediments was primarily controlled by stochastic and deterministic processes, respectively. These findings provide valuable insights into the archaeal community assembly processes and significantly contribute to a deeper understanding of the environmental adaptability of abundant and rare taxa in Arctic marine sediments.

RevDate: 2023-07-05

Kiledal EA, Shaw M, Polson SW, et al (2023)

Metagenomic Analysis of a Concrete Bridge Reveals a Microbial Community Dominated by Halophilic Bacteria and Archaea.

Microbiology spectrum [Epub ahead of print].

Concrete hosts a small but diverse microbiome that changes over time. Shotgun metagenomic sequencing would enable assessment of both the diversity and function of the microbial community in concrete, but a number of unique challenges make this difficult for concrete samples. The high concentration of divalent cations in concrete interferes with nucleic acid extraction, and the extremely low biomass in concrete means that DNA from laboratory contamination may be a large fraction of the sequence data. Here, we develop an improved method for DNA extraction from concrete, with higher yield and lower laboratory contamination. To show that this method provides DNA of sufficient quality and quantity to do shotgun metagenomic sequencing, DNA was extracted from a sample of concrete obtained from a road bridge and sequenced with an Illumina MiSeq system. This microbial community was dominated by halophilic Bacteria and Archaea, with enriched functional pathways related to osmotic stress responses. Although this was a pilot-scale effort, we demonstrate that metagenomic sequencing can be used to characterize microbial communities in concrete and that older concrete structures may host different microbes than recently poured concrete. IMPORTANCE Prior work on the microbial communities of concrete focused on the surfaces of concrete structures such as sewage pipes or bridge pilings, where thick biofilms were easy to observe and sample. Because the biomass inside concrete is so low, more recent analyses of the microbial communities inside concrete used amplicon sequencing methods to describe those communities. However, to understand the activity and physiology of microbes in concrete, or to develop living infrastructure, we must develop more direct methods of community analysis. The method developed here for DNA extraction and metagenomic sequencing can be used for analysis of microbial communities inside concrete and can likely be adapted for other cementitious materials.

RevDate: 2023-07-05
CmpDate: 2023-07-05

Li XX, Tan S, Cheng M, et al (2023)

Salinilacihabitans rarus gen. nov., sp. nov., Natrononativus amylolyticus gen. nov., sp. nov., Natronobeatus ordinarius gen. nov., sp. nov., and Halovivax gelatinilyticus sp. nov., halophilic archaea, isolated from a salt lake and soda lakes.

Extremophiles : life under extreme conditions, 27(2):15.

Four halophilic archaea strains, AD-4[T], CGA30[T], CGA73[T], and WLHSJ27[T], were isolated from a salt lake and two soda lakes located in different regions of China. The 16S rRNA and rpoB' gene sequence similarities among strains AD-4[T], CGA30[T], CGA73[T], WLHSJ27[T], and the current species of the family Natrialbaceae were 90.9-97.5% and 83.1-91.8%, respectively. The phylogenetic and phylogenomic analyses revealed that these four strains separated from existing genera in the family Natrialbaceae and formed distant branches. The ANI, isDDH, and AAI values among these four strains and the current members of the family Natrialbaceae were 72-79%, 20-25%, and 63-73%, respectively, much lower than the threshold values for species demarcation. Strains AD-4[T], CGA73[T], and WLHSJ27[T] may represent three novel genera of the family Natrialbaceae according to the cutoff value of AAI (≤ 76%) proposed to differentiate genera within the family Natrialbaceae. These four strains could be distinguished from the related genera according to differential phenotypic characteristics. The major phospholipids of these four strains were identical while their glycolipid profiles were diverse. DGD-1 is a major glycolipid found in strain AD-4[T], trace glycolipids, DGD-1, and S-DGD-1, and (or) S-TGD-1 was found in the other three strains. The major respiratory quinones detected in the four strains were menaquinone MK-8 and MK-8(H2). This polyphasic classification indicated that strains AD-4[T], CGA73[T], and WLHSJ27[T] represent three novel species of three new genera with the family Natrialbaceae, and strain CGA30[T] represents a novel species of Halovivax.

RevDate: 2023-07-03

Li B, Liang J, Phillips MA, et al (2023)

Neofunctionalization of S-adenosylmethionine decarboxylase into pyruvoyl-dependent L-ornithine and L-arginine decarboxylases is widespread in bacteria and archaea.

The Journal of biological chemistry pii:S0021-9258(23)02033-1 [Epub ahead of print].

S-Adenosylmethionine decarboxylase (AdoMetDC/SpeD) is a key polyamine biosynthetic enzyme required for conversion of putrescine to spermidine. Autocatalytic self-processing of the AdoMetDC/SpeD proenzyme generates a pyruvoyl cofactor from an internal serine. Recently, we discovered that diverse bacteriophages encode AdoMetDC/SpeD homologs that lack AdoMetDC activity and instead decarboxylate L-ornithine or L-arginine. We reasoned that neofunctionalized AdoMetDC/SpeD homologs were unlikely to have emerged in bacteriophages and were probably acquired from ancestral bacterial hosts. To test this hypothesis, we sought to identify candidate AdoMetDC/SpeD homologs encoding L-ornithine and L-arginine decarboxylases in bacteria and archaea. We searched for the anomalous presence of AdoMetDC/SpeD homologs in the absence of its obligatory partner enzyme spermidine synthase, or the presence of two AdoMetDC/SpeD homologs encoded in the same genome. Biochemical characterization of candidate neofunctionalized genes confirmed lack of AdoMetDC activity, and functional presence of L-ornithine or L-arginine decarboxylase activity in proteins from phyla Actinomycetota, Armatimonadota, Planctomycetota, Melainabacteria, Perigrinibacteria, Atribacteria, Chloroflexota, Sumerlaeota, Omnitrophota, Lentisphaerota and Euryarchaeota, the bacterial candidate phyla radiation and DPANN archaea, and the δ-Proteobacteria class. Phylogenetic analysis indicated that L-arginine decarboxylases emerged at least three times from AdoMetDC/SpeD, whereas L-ornithine decarboxylases arose only once, potentially from the AdoMetDC/SpeD-derived L-arginine decarboxylases, revealing unsuspected polyamine metabolic plasticity. Horizontal transfer of the neofunctionalized genes appears to be the more prevalent mode of dissemination. We identified fusion proteins of bona fide AdoMetDC/SpeD with homologous L-ornithine decarboxylases that possess two, unprecedented internal protein-derived pyruvoyl cofactors. These fusion proteins suggest a plausible model for the evolution of the eukaryotic AdoMetDC.

RevDate: 2023-06-30

Johnsen U, Ortjohann M, Reinhardt A, et al (2023)

Discovery of a novel transcriptional regulator of sugar catabolism in archaea.

Molecular microbiology [Epub ahead of print].

The haloarchaeon Haloferax volcanii degrades D-glucose via the semiphosphorylative Entner-Doudoroff pathway and D-fructose via a modified Embden-Meyerhof pathway. Here, we report the identification of GfcR, a novel type of transcriptional regulator that functions as an activator of both D-glucose and D-fructose catabolism. We find that in the presence of D-glucose, GfcR activates gluconate dehydratase, glyceraldehyde-3-phosphate dehydrogenase and pyruvate kinase and also acts as activator of the phosphotransferase system and of fructose-1,6-bisphosphate aldolase, which are involved in uptake and degradation of D-fructose. In addition, glyceraldehyde-3-phosphate dehydrogenase and pyruvate kinase are activated by GfcR in the presence of D-fructose and also during growth on D-galactose and glycerol. Electrophoretic mobility shift assays indicate that GfcR binds directly to promoters of regulated genes. Specific intermediates of the degradation pathways of the three hexoses and of glycerol were identified as inducer molecules of GfcR. GfcR is composed of a phosphoribosyltransferase (PRT) domain with an N-terminal helix-turn-helix motif and thus shows homology to PurR of Gram-positive bacteria that is involved in the transcriptional regulation of nucleotide biosynthesis. We propose that GfcR of H. volcanii evolved from a PRT-like enzyme to attain a function as a transcriptional regulator of central sugar catabolic pathways in archaea.

RevDate: 2023-06-30
CmpDate: 2023-06-30

Wang J, Qu YN, Evans PN, et al (2023)

Evidence for nontraditional mcr-containing archaea contributing to biological methanogenesis in geothermal springs.

Science advances, 9(26):eadg6004.

Recent discoveries of methyl-coenzyme M reductase-encoding genes (mcr) in uncultured archaea beyond traditional euryarchaeotal methanogens have reshaped our view of methanogenesis. However, whether any of these nontraditional archaea perform methanogenesis remains elusive. Here, we report field and microcosm experiments based on [13]C-tracer labeling and genome-resolved metagenomics and metatranscriptomics, revealing that nontraditional archaea are predominant active methane producers in two geothermal springs. Archaeoglobales performed methanogenesis from methanol and may exhibit adaptability in using methylotrophic and hydrogenotrophic pathways based on temperature/substrate availability. A five-year field survey found Candidatus Nezhaarchaeota to be the predominant mcr-containing archaea inhabiting the springs; genomic inference and mcr expression under methanogenic conditions strongly suggested that this lineage mediated hydrogenotrophic methanogenesis in situ. Methanogenesis was temperature-sensitive , with a preference for methylotrophic over hydrogenotrophic pathways when incubation temperatures increased from 65° to 75°C. This study demonstrates an anoxic ecosystem wherein methanogenesis is primarily driven by archaea beyond known methanogens, highlighting diverse nontraditional mcr-containing archaea as previously unrecognized methane sources.

RevDate: 2023-06-28

Mapelli-Brahm P, Gómez-Villegas P, Gonda ML, et al (2023)

Microalgae, Seaweeds and Aquatic Bacteria, Archaea, and Yeasts: Sources of Carotenoids with Potential Antioxidant and Anti-Inflammatory Health-Promoting Actions in the Sustainability Era.

Marine drugs, 21(6): pii:md21060340.

Carotenoids are a large group of health-promoting compounds used in many industrial sectors, such as foods, feeds, pharmaceuticals, cosmetics, nutraceuticals, and colorants. Considering the global population growth and environmental challenges, it is essential to find new sustainable sources of carotenoids beyond those obtained from agriculture. This review focuses on the potential use of marine archaea, bacteria, algae, and yeast as biological factories of carotenoids. A wide variety of carotenoids, including novel ones, were identified in these organisms. The role of carotenoids in marine organisms and their potential health-promoting actions have also been discussed. Marine organisms have a great capacity to synthesize a wide variety of carotenoids, which can be obtained in a renewable manner without depleting natural resources. Thus, it is concluded that they represent a key sustainable source of carotenoids that could help Europe achieve its Green Deal and Recovery Plan. Additionally, the lack of standards, clinical studies, and toxicity analysis reduces the use of marine organisms as sources of traditional and novel carotenoids. Therefore, further research on the processing of marine organisms, the biosynthetic pathways, extraction procedures, and examination of their content is needed to increase carotenoid productivity, document their safety, and decrease costs for their industrial implementation.

RevDate: 2023-06-23

Carré L, Gonzalez D, Girard É, et al (2023)

Effects of chaotropic salts on global proteome stability in halophilic archaea: Implications for life signatures on Mars.

Environmental microbiology [Epub ahead of print].

Halophilic archaea thriving in hypersaline environments, such as salt lakes, offer models for putative life in extraterrestrial brines such as those found on Mars. However, little is known about the effect of the chaotropic salts that could be found in such brines, such as MgCl2 , CaCl2 and (per)chlorate salts, on complex biological samples like cell lysates which could be expected to be more representative of biomarkers left behind putative extraterrestrial life forms. We used intrinsic fluorescence to study the salt dependence of proteomes extracted from five halophilic strains: Haloarcula marismortui, Halobacterium salinarum, Haloferax mediterranei, Halorubrum sodomense and Haloferax volcanii. These strains were isolated from Earth environments with different salt compositions. Among the five strains that were analysed, H. mediterranei stood out as a results of its high dependency on NaCl for its proteome stabilization. Interestingly, the results showed contrasting denaturation responses of the proteomes to chaotropic salts. In particular, the proteomes of strains that are most dependent or tolerant on MgCl2 for growth exhibited higher tolerance towards chaotropic salts that are abundant in terrestrial and Martian brines. These experiments bridge together global protein properties and environmental adaptation and help guide the search for protein-like biomarkers in extraterrestrial briny environments.

RevDate: 2023-06-21

Iacono R, De Lise F, Moracci M, et al (2023)

Glycoside hydrolases from (hyper)thermophilic archaea: structure, function, and applications.

Essays in biochemistry pii:233166 [Epub ahead of print].

(Hyper)thermophilic archaeal glycosidases are enzymes that catalyze the hydrolysis of glycosidic bonds to break down complex sugars and polysaccharides at high temperatures. These enzymes have an unique structure that allows them to remain stable and functional in extreme environments such as hot springs and hydrothermal vents. This review provides an overview of the current knowledge and milestones on the structures and functions of (hyper)thermophilic archaeal glycosidases and their potential applications in various fields. In particular, this review focuses on the structural characteristics of these enzymes and how these features relate to their catalytic activity by discussing different types of (hyper)thermophilic archaeal glycosidases, including β-glucosidases, chitinase, cellulases and α-amylases, describing their molecular structures, active sites, and mechanisms of action, including their role in the hydrolysis of carbohydrates. By providing a comprehensive overview of (hyper)thermophilic archaeal glycosidases, this review aims to stimulate further research into these fascinating enzymes.

RevDate: 2023-06-20

Jarrell KF, Albers SV, JNS Machado (2021)

A comprehensive history of motility and Archaellation in Archaea.

FEMS microbes, 2:xtab002.

Each of the three Domains of life, Eukarya, Bacteria and Archaea, have swimming structures that were all originally called flagella, despite the fact that none were evolutionarily related to either of the other two. Surprisingly, this was true even in the two prokaryotic Domains of Bacteria and Archaea. Beginning in the 1980s, evidence gradually accumulated that convincingly demonstrated that the motility organelle in Archaea was unrelated to that found in Bacteria, but surprisingly shared significant similarities to type IV pili. This information culminated in the proposal, in 2012, that the 'archaeal flagellum' be assigned a new name, the archaellum. In this review, we provide a historical overview on archaella and motility research in Archaea, beginning with the first simple observations of motile extreme halophilic archaea a century ago up to state-of-the-art cryo-tomography of the archaellum motor complex and filament observed today. In addition to structural and biochemical data which revealed the archaellum to be a type IV pilus-like structure repurposed as a rotating nanomachine (Beeby et al. 2020), we also review the initial discoveries and subsequent advances using a wide variety of approaches to reveal: complex regulatory events that lead to the assembly of the archaellum filaments (archaellation); the roles of the various archaellum proteins; key post-translational modifications of the archaellum structural subunits; evolutionary relationships; functions of archaella other than motility and the biotechnological potential of this fascinating structure. The progress made in understanding the structure and assembly of the archaellum is highlighted by comparing early models to what is known today.

RevDate: 2023-06-19

Pessi IS, Rutanen A, J Hultman (2022)

Candidatus Nitrosopolaris, a genus of putative ammonia-oxidizing archaea with a polar/alpine distribution.

FEMS microbes, 3:xtac019.

Ammonia-oxidizing archaea (AOA) are key players in the nitrogen cycle of polar soils. Here, we analyzed metagenomic data from tundra soils in Rásttigáisá, Norway, and recovered four metagenome-assembled genomes (MAGs) assigned to the genus 'UBA10452', an uncultured lineage of putative AOA in the order Nitrososphaerales ('terrestrial group I.1b'), phylum Thaumarchaeota. Analysis of other eight previously reported MAGs and publicly available amplicon sequencing data revealed that the UBA10452 lineage is predominantly found in acidic polar and alpine soils. In particular, UBA10452 MAGs were more abundant in highly oligotrophic environments such as mineral permafrost than in more nutrient-rich, vegetated tundra soils. UBA10452 MAGs harbour multiple copies of genes related to cold tolerance, particularly genes involved in DNA replication and repair. Based on the phylogenetic, biogeographic, and ecological characteristics of 12 UBA10452 MAGs, which include a high-quality MAG (90.8% complete, 3.9% redundant) with a nearly complete 16S rRNA gene, we propose a novel Candidatus genus, Ca. Nitrosopolaris, with four species representing clear biogeographic/habitat clusters.

RevDate: 2023-06-18

Elcheninov AG, Ugolkov YA, Elizarov IM, et al (2023)

Cellulose metabolism in halo(natrono)archaea: a comparative genomics study.

Frontiers in microbiology, 14:1112247.

Extremely halophilic archaea are one of the principal microbial community components in hypersaline environments. The majority of cultivated haloarchaea are aerobic heterotrophs using peptides or simple sugars as carbon and energy sources. At the same time, a number of novel metabolic capacities of these extremophiles were discovered recently among which is a capability of growing on insoluble polysaccharides such as cellulose and chitin. Still, polysaccharidolytic strains are in minority among cultivated haloarchaea and their capacities of hydrolyzing recalcitrant polysaccharides are hardly investigated. This includes the mechanisms and enzymes involved in cellulose degradation, which are well studied for bacterial species, while almost unexplored in archaea and haloarchaea in particular. To fill this gap, a comparative genomic analysis of 155 cultivated representatives of halo(natrono)archaea, including seven cellulotrophic strains belonging to the genera Natronobiforma, Natronolimnobius, Natrarchaeobius, Halosimplex, Halomicrobium and Halococcoides was performed. The analysis revealed a number of cellulases, encoded in the genomes of cellulotrophic strains but also in several haloarchaea, for which the capacity to grow on cellulose was not shown. Surprisingly, the cellulases genes, especially of GH5, GH9 and GH12 families, were significantly overrepresented in the cellulotrophic haloarchaea genomes in comparison with other cellulotrophic archaea and even cellulotrophic bacteria. Besides cellulases, the genes for GH10 and GH51 families were also abundant in the genomes of cellulotrophic haloarchaea. These results allowed to propose the genomic patterns, determining the capability of haloarchaea to grow on cellulose. The patterns helped to predict cellulotrophic capacity for several halo(natrono)archaea, and for three of them it was experimentally confirmed. Further genomic search revealed that glucose and cellooligosaccharides import occurred by means of porters and ABC (ATP-binding cassette) transporters. Intracellular glucose oxidation occurred through glycolysis or the semi-phosphorylative Entner-Dudoroff pathway which occurrence was strain-specific. Comparative analysis of CAZymes toolbox and available cultivation-based information allowed proposing two possible strategies used by haloarchaea capable of growing on cellulose: so-called specialists are more effective in degradation of cellulose while generalists are more flexible in nutrient spectra. Besides CAZymes profiles the groups differed in genome sizes, as well as in variability of mechanisms of import and central metabolism of sugars.

RevDate: 2023-06-15

Taglialegna A (2023)

A plasmid to modify Archaea.

Nature reviews. Microbiology [Epub ahead of print].

RevDate: 2023-06-15

Thompson TP, Busetti A, BF Gilmore (2023)

Quorum Sensing in Halorubrum saccharovorum Facilitates Cross-Domain Signaling between Archaea and Bacteria.

Microorganisms, 11(5): pii:microorganisms11051271.

Quorum Sensing (QS) is a well-studied intercellular communication mechanism in bacteria, regulating collective behaviors such as biofilm formation, virulence, and antibiotic resistance. However, cell-cell signaling in haloarchaea remains largely unexplored. The coexistence of bacteria and archaea in various environments, coupled with the known cell-cell signaling mechanisms in both prokaryotic and eukaryotic microorganisms and the presence of cell-cell signaling mechanisms in both prokaryotic and eukaryotic microorganisms, suggests a possibility for haloarchaea to possess analogous cell-cell signaling or QS systems. Recently, N-acylhomoserine lactone (AHL)-like compounds were identified in haloarchaea; yet, their precise role-for example, persister cell formation-remains ambiguous. This study investigated the capacity of crude supernatant extract from the haloarchaeon Halorubrum saccharovorum CSM52 to stimulate bacterial AHL-dependent QS phenotypes using bioreporter strains. Our findings reveal that these crude extracts induced several AHL-dependent bioreporters and modulated pyocyanin and pyoverdine production in Pseudomonas aeruginosa. Importantly, our study suggests cross-domain communication between archaea and bacterial pathogens, providing evidence for archaea potentially influencing bacterial virulence. Using Thin Layer Chromatography overlay assays, lactonolysis, and colorimetric quantification, the bioactive compound was inferred to be a chemically modified AHL-like compound or a diketopiperazine-like molecule, potentially involved in biofilm formation in H. saccharovorum CSM52. This study offers new insights into putative QS mechanisms in haloarchaea and their potential role in interspecies communication and coordination, thereby enriching our understanding of microbial interactions in diverse environments.

RevDate: 2023-06-15

Payá G, Bautista V, Camacho M, et al (2023)

Comprehensive Bioinformatics Analysis of the Biodiversity of Lsm Proteins in the Archaea Domain.

Microorganisms, 11(5): pii:microorganisms11051196.

The Sm protein superfamily includes Sm, like-Sm (Lsm), and Hfq proteins. Sm and Lsm proteins are found in the Eukarya and Archaea domains, respectively, while Hfq proteins exist in the Bacteria domain. Even though Sm and Hfq proteins have been extensively studied, archaeal Lsm proteins still require further exploration. In this work, different bioinformatics tools are used to understand the diversity and distribution of 168 Lsm proteins in 109 archaeal species to increase the global understanding of these proteins. All 109 archaeal species analyzed encode one to three Lsm proteins in their genome. Lsm proteins can be classified into two groups based on molecular weight. Regarding the gene environment of lsm genes, many of these genes are located adjacent to transcriptional regulators of the Lrp/AsnC and MarR families, RNA-binding proteins, and ribosomal protein L37e. Notably, only proteins from species of the class Halobacteria conserved the internal and external residues of the RNA-binding site identified in Pyrococcus abyssi, despite belonging to different taxonomic orders. In most species, the Lsm genes show associations with 11 genes: rpl7ae, rpl37e, fusA, flpA, purF, rrp4, rrp41, hel308, rpoD, rpoH, and rpoN. We propose that most archaeal Lsm proteins are related to the RNA metabolism, and the larger Lsm proteins could perform different functions and/or act through other mechanisms of action.

RevDate: 2023-06-12

Tong Y, Wu X, Liu Y, et al (2023)

Alternative Z-genome biosynthesis pathway shows evolutionary progression from Archaea to phage.

Nature microbiology [Epub ahead of print].

Many bacteriophages evade bacterial immune recognition by substituting adenine with 2,6-diaminopurine (Z) in their genomes. The Z-genome biosynthetic pathway involves PurZ that belongs to the PurA (adenylosuccinate synthetase) family and bears particular similarity to archaeal PurA. However, how the transition of PurA to PurZ occurred during evolution is not clear; recapturing this process may shed light on the origin of Z-containing phages. Here we describe the computer-guided identification and biochemical characterization of a naturally existing PurZ variant, PurZ0, which uses guanosine triphosphate as the phosphate donor rather than the ATP used by PurZ. The atomic resolution structure of PurZ0 reveals a guanine nucleotide binding pocket highly analogous to that of archaeal PurA. Phylogenetic analyses suggest PurZ0 as an intermediate during the evolution of archaeal PurA to phage PurZ. Maintaining the balance of different purines necessitates further evolvement of guanosine triphosphate-using PurZ0 to ATP-using PurZ in adaptation to Z-genome life.

RevDate: 2023-06-12

van der Does C, Braun F, Ren H, et al (2023)

Putative nucleotide-based second messengers in archaea.

microLife, 4:uqad027.

Second messengers transfer signals from changing intra- and extracellular conditions to a cellular response. Over the last few decades, several nucleotide-based second messengers have been identified and characterized in especially bacteria and eukaryotes. Also in archaea, several nucleotide-based second messengers have been identified. This review will summarize our understanding of nucleotide-based second messengers in archaea. For some of the nucleotide-based second messengers, like cyclic di-AMP and cyclic oligoadenylates, their roles in archaea have become clear. Cyclic di-AMP plays a similar role in osmoregulation in euryarchaea as in bacteria, and cyclic oligoadenylates are important in the Type III CRISPR-Cas response to activate CRISPR ancillary proteins involved in antiviral defense. Other putative nucleotide-based second messengers, like 3',5'- and 2',3'-cyclic mononucleotides and adenine dinucleotides, have been identified in archaea, but their synthesis and degradation pathways, as well as their functions as secondary messengers, still remain to be demonstrated. In contrast, 3'-3'-cGAMP has not yet been identified in archaea, but the enzymes required to synthesize 3'-3'-cGAMP have been found in several euryarchaeotes. Finally, the widely distributed bacterial second messengers, cyclic diguanosine monophosphate and guanosine (penta-)/tetraphosphate, do not appear to be present in archaea.

RevDate: 2023-06-11

Jia Z, Lipus D, Burckhardt O, et al (2023)

Enrichment of rare methanogenic Archaea shows their important ecological role in natural high-CO2 terrestrial subsurface environments.

Frontiers in microbiology, 14:1105259.

INTRODUCTION: Long-term stability of underground CO2 storage is partially affected by microbial activity but our knowledge of these effects is limited, mainly due to a lack of sites. A consistently high flux of mantle-derived CO2 makes the Eger Rift in the Czech Republic a natural analogue to underground CO2 storage. The Eger Rift is a seismically active region and H2 is produced abiotically during earthquakes, providing energy to indigenous microbial communities.

METHODS: To investigate the response of a microbial ecosystem to high levels of CO2 and H2, we enriched microorganisms from samples from a 239.5 m long drill core from the Eger Rift. Microbial abundance, diversity and community structure were assessed using qPCR and 16S rRNA gene sequencing. Enrichment cultures were set up with minimal mineral media and H2/CO2 headspace to simulate a seismically active period with elevated H2.

RESULTS AND DISCUSSION: Methane headspace concentrations in the enrichments indicated that active methanogens were almost exclusively restricted to enrichment cultures from Miocene lacustrine deposits (50-60 m), for which we observed the most significant growth. Taxonomic assessment showed microbial communities in these enrichments to be less diverse than those with little or no growth. Active enrichments were especially abundant in methanogens of the taxa Methanobacterium and Methanosphaerula. Concurrent to the emergence of methanogenic archaea, we also observed sulfate reducers with the metabolic ability to utilize H2 and CO2, specifically the genus Desulfosporosinus, which were able to outcompete methanogens in several enrichments. Low microbial abundance and a diverse non-CO2 driven microbial community, similar to that in drill core samples, also reflect the inactivity in these cultures. Significant growth of sulfate reducing and methanogenic microbial taxa, which make up only a small fraction of the total microbial community, emphasize the need to account for rare biosphere taxa when assessing the metabolic potential of microbial subsurface populations. The observation that CO2 and H2-utilizing microorganisms could only be enriched from a narrow depth interval suggests that factors such as sediment heterogeneity may also be important. This study provides new insight on subsurface microbes under the influence of high CO2 concentrations, similar to those found in CCS sites.

RevDate: 2023-06-05

Catchpole RJ, Barbe V, Magdelenat G, et al (2023)

A self-transmissible plasmid from a hyperthermophile that facilitates genetic modification of diverse Archaea.

Nature microbiology [Epub ahead of print].

Conjugative plasmids are self-transmissible mobile genetic elements that transfer DNA between host cells via type IV secretion systems (T4SS). While T4SS-mediated conjugation has been well-studied in bacteria, information is sparse in Archaea and known representatives exist only in the Sulfolobales order of Crenarchaeota. Here we present the first self-transmissible plasmid identified in a Euryarchaeon, Thermococcus sp. 33-3. The 103 kbp plasmid, pT33-3, is seen in CRISPR spacers throughout the Thermococcales order. We demonstrate that pT33-3 is a bona fide conjugative plasmid that requires cell-to-cell contact and is dependent on canonical, plasmid-encoded T4SS-like genes. Under laboratory conditions, pT33-3 transfers to various Thermococcales and transconjugants propagate at 100 °C. Using pT33-3, we developed a genetic toolkit that allows modification of phylogenetically diverse Archaeal genomes. We demonstrate pT33-3-mediated plasmid mobilization and subsequent targeted genome modification in previously untransformable Thermococcales species, and extend this process to interphylum transfer to a Crenarchaeon.

RevDate: 2023-06-01

Zehnle H, Laso-Pérez R, Lipp J, et al (2023)

Candidatus Alkanophaga archaea from Guaymas Basin hydrothermal vent sediment oxidize petroleum alkanes.

Nature microbiology [Epub ahead of print].

Methanogenic and methanotrophic archaea produce and consume the greenhouse gas methane, respectively, using the reversible enzyme methyl-coenzyme M reductase (Mcr). Recently, Mcr variants that can activate multicarbon alkanes have been recovered from archaeal enrichment cultures. These enzymes, called alkyl-coenzyme M reductase (Acrs), are widespread in the environment but remain poorly understood. Here we produced anoxic cultures degrading mid-chain petroleum n-alkanes between pentane (C5) and tetradecane (C14) at 70 °C using oil-rich Guaymas Basin sediments. In these cultures, archaea of the genus Candidatus Alkanophaga activate the alkanes with Acrs and completely oxidize the alkyl groups to CO2. Ca. Alkanophaga form a deep-branching sister clade to the methanotrophs ANME-1 and are closely related to the short-chain alkane oxidizers Ca. Syntrophoarchaeum. Incapable of sulfate reduction, Ca. Alkanophaga shuttle electrons released from alkane oxidation to the sulfate-reducing Ca. Thermodesulfobacterium syntrophicum. These syntrophic consortia are potential key players in petroleum degradation in heated oil reservoirs.

RevDate: 2023-06-01

Hou G, Wazir ZG, Liu J, et al (2023)

Effects of sulfadiazine and Cu on soil potential nitrification and ammonia-oxidizing archaea and bacteria communities across different soils.

Frontiers in microbiology, 14:1153199.

INTRODUCTION: Sulfadiazine (SDZ) and copper (Cu) are frequently detected in agricultural soils, but little is known on their single or combined impact on ammonia oxidizing microbial community and function across different soils.

METHODS: In this study, a microcosm was conducted to distinguish the microbial ecotoxicity of SDZ and Cu across different soils by analyzing soil potential nitrification rate (PNR) and the amoA gene sequences.

RESULTS: The results showed that the single spiking of SDZ caused a consistent decrease of soil PNR among three tested soils, but no consistent synergistic inhibition of SDZ and Cu was observed across these soils. Moreover, across three tested soils, the distinct responses to the single or joint exposure of SDZ and Cu were found in amoA gene abundance, and diversity as well as the identified genus taxa of ammonia-oxidizing archaea (AOA) and bacteria (AOB). Meanwhile, only the specific genus taxa of AOA or AOB consistently corresponded to the variation of soil PNR across different treated soils. The further principal component analysis (PCA) exhibited that the variable influence of SDZ and Cu on ammonia oxidizing microbial community and function was greatly dependent on soil type.

DISCUSSION: Therefore, in addition to ecological functionality and the specific prokaryotic taxa, soil microbial ecotoxicity of SDZ and Cu also was dependent on edaphic factors derived from soil types. This study proposes an integrative assessment of soil properties and multiple microbial targets to soil contamination management.

RevDate: 2023-05-31

Wang BB, Bao CX, Sun YP, et al (2023)

Halobacterium wangiae sp. nov. and Halobacterium zhouii sp. nov., two extremely halophilic archaea isolated from sediment of a salt lake and saline soil of an inland saltern.

International journal of systematic and evolutionary microbiology, 73(5):.

Two novel halophilic archaeal strains, Gai3-17[T] and XZYJT26[T], were isolated from the sediment of Gaize salt lake and the saline soil of Mangkang ancient solar saltern in Tibet, PR China, respectively. Strains Gai3-17[T] and XZYJT26[T] were related to each other (96.5 and 89.7% similarity, respectively) and showed 97.5-95.4 and 91.5-87.7% similarities to the current members of Halobacterium based on 16S rRNA and rpoB' genes. The phylogenomic analysis indicated that strains Gai3-17[T] and XZYJT26[T] formed two distinct clades and clustered with the Halobacterium species. The two strains can be differentiated from the type strains of the six species with validly published names based on several phenotypic characteristics. The phospholipids of the two strains were phosphatidic acid, phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester. One major glycolipid, sulphated galactosyl mannosyl glucosyl diether, was detected in strain Gai3-17[T], while four glycolipids, mannosyl glucosyl diether, sulphated mannosyl glucosyl diether, disulphated mannosyl glucosyl diether and sulphated galactosyl mannosyl glucosyl diether were observed in strain XZYJT26[T]. The average nucleotide identity, digital DNA-DNA hybridization and amino acid identity values among the two strains and the members of Halobacterium were no more than 81, 25 and 77 %, respectively. These overall genome-related indices were below the threshold values for species boundary, indicating that strains Gai3-17[T] and XZYJT26[T] represent two novel species of Halobacterium. Thus, two novel species, Halobacterium wangiae sp. nov. and Halobacterium zhouii sp. nov., are proposed to accommodate strains Gai3-17[T] (=CGMCC 1.16101[T]=JCM 33551[T]) and XZYJT26[T] (=CGMCC 1.16682[T]=JCM 33556[T]), respectively.

RevDate: 2023-05-30

Ávila-Román J, Gómez-Villegas P, de Carvalho CCCR, et al (2023)

Up-Regulation of the Nrf2/HO-1 Antioxidant Pathway in Macrophages by an Extract from a New Halophilic Archaea Isolated in Odiel Saltworks.

Antioxidants (Basel, Switzerland), 12(5):.

The production of reactive oxygen species (ROS) plays an important role in the progression of many inflammatory diseases. The search for antioxidants with the ability for scavenging free radicals from the body cells that reduce oxidative damage is essential to prevent and treat these pathologies. Haloarchaea are extremely halophilic microorganisms that inhabit hypersaline environments, such as saltworks or salt lakes, where they have to tolerate high salinity, and elevated ultraviolet (UV) and infrared radiations. To cope with these extreme conditions, haloarchaea have developed singular mechanisms to maintain an osmotic balance with the medium, and are endowed with unique compounds, not found in other species, with bioactive properties that have not been fully explored. This study aims to assess the potential of haloarchaea as a new source of natural antioxidant and anti-inflammatory agents. A carotenoid-producing haloarchaea was isolated from Odiel Saltworks (OS) and identified on the basis of its 16S rRNA coding gene sequence as a new strain belonging to the genus Haloarcula. The Haloarcula sp. OS acetone extract (HAE) obtained from the biomass contained bacterioruberin and mainly C18 fatty acids, and showed potent antioxidant capacity using ABTS assay. This study further demonstrates, for the first time, that pretreatment with HAE of lipopolysaccharide (LPS)-stimulated macrophages results in a reduction in ROS production, a decrease in the pro-inflammatory cytokines TNF-α and IL-6 levels, and up-regulation of the factor Nrf2 and its target gene heme oxygenase-1 (HO-1), supporting the potential of the HAE as a therapeutic agent in the treatment of oxidative stress-related inflammatory diseases.

RevDate: 2023-05-25

Liu J, Soler N, Gorlas A, et al (2021)

Extracellular membrane vesicles and nanotubes in Archaea.

microLife, 2:uqab007.

Membrane-bound extracellular vesicles (EVs) are secreted by cells from all three domains of life and their implication in various biological processes is increasingly recognized. In this review, we summarize the current knowledge on archaeal EVs and nanotubes, and emphasize their biological significance. In archaea, the EVs and nanotubes have been largely studied in representative species from the phyla Crenarchaeota and Euryarchaeota. The archaeal EVs have been linked to several physiological processes such as detoxification, biomineralization and transport of biological molecules, including chromosomal, viral or plasmid DNA, thereby taking part in genome evolution and adaptation through horizontal gene transfer. The biological significance of archaeal nanotubes is yet to be demonstrated, although they could participate in EV biogenesis or exchange of cellular contents. We also discuss the biological mechanisms leading to EV/nanotube biogenesis in Archaea. It has been recently demonstrated that, similar to eukaryotes, EV budding in crenarchaea depends on the ESCRT machinery, whereas the mechanism of EV budding in euryarchaeal lineages, which lack the ESCRT-III homologues, remains unknown.

RevDate: 2023-05-22
CmpDate: 2023-05-22

Ma X, Hu Y, Li XX, et al (2023)

Halomicroarcula laminariae sp. nov. and Halomicroarcula marina sp. nov., extremely halophilic archaea isolated from salted brown alga Laminaria and coastal saline-alkali lands.

International journal of systematic and evolutionary microbiology, 73(5):.

Four extremely halophilic archaeal strains, LYG-108[T], LYG-24, DT1[T] and YSSS71, were isolated from salted Laminaria produced in Lianyungang and saline soil from the coastal beach at Jiangsu, PR China. The four strains were found to be related to the current species of Halomicroarcula (showing 88.1-98.5% and 89.3-93.6% similarities, respectively) as revealed by phylogenetic analysis based on 16S rRNA and rpoB' genes. These phylogenies were fully supported by the phylogenomic analysis, and the overall genome-related indexes (average nucleotide identity, DNA-DNA hybridization and average amino acid identity) among these four strains and the Halomicroarcula species were 77-84 %, 23-30 % and 71-83 %, respectively, clearly below the threshold values for species demarcation. Additionally, the phylogenomic and comparative genomic analyses revealed that Halomicroarcula salina YGH18[T] is related to the current species of Haloarcula rather than those of Halomicroarcula, Haloarcula salaria Namwong et al. 2011 is a later heterotypic synonym of Haloarcula argentinensis Ihara et al. 1997, and Haloarcula quadrata Oren et al. 1999 is a later heterotypic synonym of Haloarcula marismortui Oren et al. 1990. The major polar lipids of strains LYG-108[T], LYG-24, DT1[T] and YSSS71 were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulphate, sulphated mannosyl glucosyl diether and additional glycosyl-cardiolipins. All these results showed that strains LYG-108[T] (=CGMCC 1.13607[T]=JCM 32950[T]) and LYG-24 (=CGMCC 1.13605=JCM 32949) represent a new species of the genus Halomicroarcula, for which the name Halomicroarcula laminariae sp. nov. is proposed; strains DT1[T] (=CGMCC 1.18928[T]=JCM 35414[T]) and YSSS71 (=CGMCC 1.18783=JCM 34915) also represent a new species of the genus Halomicroarcula, for which the name Halomicroarcula marina sp. nov. is proposed.

RevDate: 2023-05-18

Wang Z, Li Y, Zheng W, et al (2023)

Ammonia oxidizing archaea and bacteria respond to different manure application rates during organic vegetable cultivation in Northwest China.

Scientific reports, 13(1):8064.

Ammonia oxidization is a critical process in nitrogen cycling that involves ammonia oxidizing archaea (AOA) and bacteria (AOB). However, the effects of different manure amounts on ammonia-oxidizing microorganisms (AOMs) over the course of organic vegetables production remains unclear. We used the amoA gene to evaluated AOMs abundance and community structure in organic vegetable fields. Quantitative PCR revealed that AOB were more abundant than AOA. Among them, the amoA copy number of AOB treated with 900 kgN ha[-1] was 21.3 times that of AOA. The potential nitrification rate was significantly correlated with AOB abundance (P < 0.0001) but not with AOA, suggesting that AOB might contribute more to nitrification than AOA. AOB sequences were classified into Nitrosomonas and Nitrosospira, and AOA into Nitrosopumilus and Nitrososphaera. Nitrosomonas and Nitrosopumilus were predominant in treatments that received manure nitrogen at ≥ 900 kg ha[-1] (52.7-56.5%) and when manure was added (72.7-99.8%), respectively, whereas Nitrosospira and Nitrososphaera occupied more than a half percentage in those that received ≤ 600 kg ha[-1] (58.4-84.9%) and no manure (59.6%). A similar manure rate resulted in more identical AOMs' community structures than greater difference manure rate. The bacterial amoA gene abundances and ratios of AOB and AOA showed significantly positive correlations with soil electrical conductivity, total carbon and nitrogen, nitrate, phosphorus, potassium, and organic carbon, indicating that these were potential key factors influencing AOMs. This study explored the AOMs' variation in organic vegetable fields in Northwest China and provided a theoretical basis and reference for the subsequent formulation of proper manure management.

RevDate: 2023-05-17

Dondjou DT, Diedhiou AG, Mbodj D, et al (2023)

Rice developmental stages modulate rhizosphere bacteria and archaea co-occurrence and sensitivity to long-term inorganic fertilization in a West African Sahelian agro-ecosystem.

Environmental microbiome, 18(1):42.

BACKGROUND: Rhizosphere microbial communities are important components of the soil-plant continuum in paddy field ecosystems. These rhizosphere communities contribute to nutrient cycling and rice productivity. The use of fertilizers is a common agricultural practice in rice paddy fields. However, the long-term impact of the fertilizers usage on the rhizosphere microbial communities at different rice developmental stages remains poorly investigated. Here, we examined the effects of long-term (27 years) N and NPK-fertilization on bacterial and archaeal community inhabiting the rice rhizosphere at three developmental stages (tillering, panicle initiation and booting) in the Senegal River Delta.

RESULTS: We found that the effect of long-term inorganic fertilization on rhizosphere microbial communities varied with the rice developmental stage, and between microbial communities in their response to N and NPK-fertilization. The microbial communities inhabiting the rice rhizosphere at panicle initiation appear to be more sensitive to long-term inorganic fertilization than those at tillering and booting stages. However, the effect of developmental stage on microbial sensitivity to long-term inorganic fertilization was more pronounced for bacterial than archaeal community. Furthermore, our data reveal dynamics of bacteria and archaea co-occurrence patterns in the rice rhizosphere, with differentiated bacterial and archaeal pivotal roles in the microbial inter-kingdom networks across developmental stages.

CONCLUSIONS: Our study brings new insights on rhizosphere bacteria and archaea co-occurrence and the long-term inorganic fertilization impact on these communities across developmental stages in field-grown rice. It would help in developing strategies for the successful manipulation of microbial communities to improve rice yields.

RevDate: 2023-05-17

Aparici D, Esclapez J, Bautista V, et al (2023)

Archaea: current and potential biotechnological applications.

Research in microbiology pii:S0923-2508(23)00055-4 [Epub ahead of print].

Archaea are microorganisms with great ability to colonize some of the most inhospitable environments in nature, managing to survive in places with extreme characteristics for most microorganisms. Its proteins and enzymes are stable and can act under extreme conditions in which other proteins and enzymes would degrade. These attributes make them ideal candidates for use in a wide range of biotechnological applications. This review describes the most important applications, both current and potential, that archaea present in Biotechnology, classifying them according to the sector to which the application is directed. It also analyzes the advantages and disadvantages of its use.

RevDate: 2023-05-16

Romero R, Gervasi MT, DiGiulio DB, et al (2023)

Are bacteria, fungi, and archaea present in the midtrimester amniotic fluid?.

Journal of perinatal medicine [Epub ahead of print].

OBJECTIVES: This study was conducted to determine whether bacteria, fungi, or archaea are detected in the amniotic fluid of patients who underwent midtrimester amniocentesis for clinical indications.

METHODS: Amniotic fluid samples from 692 pregnancies were tested by using a combination of culture and end-point polymerase chain reaction (PCR) techniques. Intra-amniotic inflammation was defined as an interleukin-6 concentration >2,935 pg/mL.

RESULTS: Microorganisms were detected in 0.3% (2/692) of cases based on cultivation, 1.73% (12/692) based on broad-range end-point PCR, and 2% (14/692) based on the combination of both methods. However, most (13/14) of these cases did not have evidence of intra-amniotic inflammation and delivered at term. Therefore, a positive culture or end-point PCR in most patients appears to have no apparent clinical significance.

CONCLUSIONS: Amniotic fluid in the midtrimester of pregnancy generally does not contain bacteria, fungi, or archaea. Interpretation of amniotic fluid culture and molecular microbiologic results is aided by the assessment of the inflammatory state of the amniotic cavity. The presence of microorganisms, as determined by culture or a microbial signal in the absence of intra-amniotic inflammation, appears to be a benign condition.

RevDate: 2023-05-16

Grünberger F, Jüttner M, Knüppel R, et al (2023)

Nanopore-based RNA sequencing deciphers the formation, processing, and modification steps of rRNA intermediates in Archaea.

RNA (New York, N.Y.) pii:rna.079636.123 [Epub ahead of print].

Ribosomal RNA (rRNA) maturation in archaea is a complex multi-step process that requires well-defined endo- and exoribonuclease activities to generate fully mature linear rRNAs. However, technical challenges prevented detailed mapping of rRNA processing steps and a systematic analysis of rRNA maturation pathways across the tree of life. In this study, we employed long-read (PCR)-cDNA and direct RNA nanopore-based sequencing to study rRNA maturation in three archaeal model organisms, namely the Euryarchaea Haloferax volcanii and Pyrococcus furiosus and the Crenarchaeon Sulfolobus acidocaldarius. Compared to standard short-read protocols, nanopore sequencing facilitates simultaneous readout of 5'- and 3'-positions, which is required for the classification of rRNA processing intermediates. More specifically, we i) accurately detect and describe rRNA maturation stages by analysis of terminal read positions of cDNA reads and thereupon ii) explore the stage-dependent installation of the KsgA-mediated dimethylations in Haloferax volcanii using basecalling and signal characteristics of direct RNA reads. Due to the single-molecule sequencing capacity of nanopore sequencing, we could detect hitherto unknown intermediates with high confidence, revealing details about the maturation of archaea-specific circular rRNA intermediates. Taken together, our study delineates common principles and unique features of rRNA processing in euryarchaeal and crenarchaeal representatives, thereby significantly expanding our understanding of rRNA maturation pathways in archaea.

RevDate: 2023-05-15
CmpDate: 2023-05-15

Pallen MJ, Rodriguez-R LM, NF Alikhan (2023)

Corrigendum: Naming the unnamed: over 65,000 Candidatus names for unnamed Archaea and Bacteria in the Genome Taxonomy Database.

International journal of systematic and evolutionary microbiology, 73(5):.

RevDate: 2023-05-08

Demey LM, Gumerov VM, Xing J, et al (2023)

Transmembrane Transcription Regulators Are Widespread in Bacteria and Archaea.

Microbiology spectrum [Epub ahead of print].

To adapt and proliferate, bacteria must sense and respond to the ever-changing environment. Transmembrane transcription regulators (TTRs) are a family of one-component transcription regulators that respond to extracellular information and influence gene expression from the cytoplasmic membrane. How TTRs function to modulate expression of their target genes while localized to the cytoplasmic membrane remains poorly understood. In part, this is due to a lack of knowledge regarding the prevalence of TTRs among prokaryotes. Here, we show that TTRs are highly diverse and prevalent throughout bacteria and archaea. Our work demonstrates that TTRs are more common than previously appreciated and are enriched within specific bacterial and archaeal phyla and that many TTRs have unique transmembrane region properties that can facilitate association with detergent-resistant membranes. IMPORTANCE One-component signal transduction systems are the major class of signal transduction systems among bacteria and are commonly cytoplasmic. TTRs are a group of unique one-component signal transduction systems that influence transcription from the cytoplasmic membrane. TTRs have been implicated in a wide array of biological pathways critical for both pathogens and human commensal organisms but were considered to be rare. Here, we demonstrate that TTRs are in fact highly diverse and broadly distributed in bacteria and archaea. Our findings suggest that transcription factors can access the chromosome and influence transcription from the membrane in both archaea and bacteria. This study challenges thus the commonly held notion that signal transduction systems require a cytoplasmic transcription factor and highlights the importance of the cytoplasmic membrane in directly influencing signal transduction.

RevDate: 2023-04-28

Hodgskiss LH, Melcher M, Kerou M, et al (2023)

Correction to: Unexpected complexity of the ammonia monooxygenase in archaea.

RevDate: 2023-04-26

Jaffe AL, Castelle CJ, JF Banfield (2023)

Habitat Transition in the Evolution of Bacteria and Archaea.

Annual review of microbiology [Epub ahead of print].

Related groups of microbes are widely distributed across Earth's habitats, implying numerous dispersal and adaptation events over evolutionary time. However, relatively little is known about the characteristics and mechanisms of these habitat transitions, particularly for populations that reside in animal microbiomes. Here, we review the literature concerning habitat transitions among a variety of bacterial and archaeal lineages, considering the frequency of migration events, potential environmental barriers, and mechanisms of adaptation to new physicochemical conditions, including the modification of protein inventories and other genomic characteristics. Cells dependent on microbial hosts, particularly bacteria from the Candidate Phyla Radiation, have undergone repeated habitat transitions from environmental sources into animal microbiomes. We compare their trajectories to those of both free-living cells-including the Melainabacteria, Elusimicrobia, and methanogenic archaea-and cellular endosymbionts and bacteriophages, which have made similar transitions. We conclude by highlighting major related topics that may be worthy of future study. Expected final online publication date for the Annual Review of Microbiology, Volume 77 is September 2023. Please see for revised estimates.

RevDate: 2023-04-26

Chen X, Molenda O, Brown CT, et al (2023)

"Candidatus Nealsonbacteria" Are Likely Biomass Recycling Ectosymbionts of Methanogenic Archaea in a Stable Benzene-Degrading Enrichment Culture.

Applied and environmental microbiology [Epub ahead of print].

The Candidate Phyla Radiation (CPR), also referred to as superphylum Patescibacteria, is a very large group of bacteria with no pure culture representatives discovered by 16S rRNA sequencing or genome-resolved metagenomic analyses of environmental samples. Within the CPR, candidate phylum Parcubacteria, previously referred to as OD1, is prevalent in anoxic sediments and groundwater. Previously, we had identified a specific member of the Parcubacteria (referred to as DGGOD1a) as an important member of a methanogenic benzene-degrading consortium. Phylogenetic analyses herein place DGGOD1a within the clade "Candidatus Nealsonbacteria." Because of its persistence over many years, we hypothesized that "Ca. Nealsonbacteria" DGGOD1a must play an important role in sustaining anaerobic benzene metabolism in the consortium. To try to identify its growth substrate, we amended the culture with a variety of defined compounds (pyruvate, acetate, hydrogen, DNA, and phospholipid), as well as crude culture lysate and three subfractions thereof. We observed the greatest (10-fold) increase in the absolute abundance of "Ca. Nealsonbacteria" DGGOD1a only when the consortium was amended with crude cell lysate. These results implicate "Ca. Nealsonbacteria" in biomass recycling. Fluorescence in situ hybridization and cryogenic transmission electron microscope images revealed that "Ca. Nealsonbacteria" DGGOD1a cells were attached to larger archaeal Methanothrix cells. This apparent epibiont lifestyle was supported by metabolic predictions from a manually curated complete genome. This is one of the first examples of bacterial-archaeal episymbiosis and may be a feature of other "Ca. Nealsonbacteria" found in anoxic environments. IMPORTANCE An anaerobic microbial enrichment culture was used to study members of candidate phyla that are difficult to grow in the lab. We were able to visualize tiny "Candidatus Nealsonbacteria" cells attached to a large Methanothrix cell, revealing a novel episymbiosis.

RevDate: 2023-04-26

Prakash O, Dodsworth JA, Dong X, et al (2023)

Proposed minimal standards for description of methanogenic archaea.

International journal of systematic and evolutionary microbiology, 73(4):.

Methanogenic archaea are a diverse, polyphyletic group of strictly anaerobic prokaryotes capable of producing methane as their primary metabolic product. It has been over three decades since minimal standards for their taxonomic description have been proposed. In light of advancements in technology and amendments in systematic microbiology, revision of the older criteria for taxonomic description is essential. Most of the previously recommended minimum standards regarding phenotypic characterization of pure cultures are maintained. Electron microscopy and chemotaxonomic methods like whole-cell protein and lipid analysis are desirable but not required. Because of advancements in DNA sequencing technologies, obtaining a complete or draft whole genome sequence for type strains and its deposition in a public database are now mandatory. Genomic data should be used for rigorous comparison to close relatives using overall genome related indices such as average nucleotide identity and digital DNA-DNA hybridization. Phylogenetic analysis of the 16S rRNA gene is also required and can be supplemented by phylogenies of the mcrA gene and phylogenomic analysis using multiple conserved, single-copy marker genes. Additionally, it is now established that culture purity is not essential for studying prokaryotes, and description of Candidatus methanogenic taxa using single-cell or metagenomics along with other appropriate criteria is a viable alternative. The revisions to the minimal criteria proposed here by the members of the Subcommittee on the Taxonomy of Methanogenic Archaea of the International Committee on Systematics of Prokaryotes should allow for rigorous yet practical taxonomic description of these important and diverse microbes.

RevDate: 2023-04-24

Dithugoe CD, Bezuidt OKI, Cavan EL, et al (2023)

Bacteria and Archaea Regulate Particulate Organic Matter Export in Suspended and Sinking Marine Particle Fractions.

mSphere [Epub ahead of print].

The biological carbon pump (BCP) in the Southern Ocean is driven by phytoplankton productivity and is a significant organic matter sink. However, the role of particle-attached (PA) and free-living (FL) prokaryotes (bacteria and archaea) and their diversity in influencing the efficiency of the BCP is still unclear. To investigate this, we analyzed the metagenomes linked to suspended and sinking marine particles from the Sub-Antarctic Southern Ocean Time Series (SOTS) by deploying a Marine Snow Catcher (MSC), obtaining suspended and sinking particulate material, determining organic carbon and nitrogen flux, and constructing metagenome-assembled genomes (MAGs). The suspended and sinking particle-pools were dominated by bacteria with the potential to degrade organic carbon. Bacterial communities associated with the sinking fraction had more genes related to the degradation of complex organic carbon than those in the suspended fraction. Archaea had the potential to drive nitrogen metabolism via nitrite and ammonia oxidation, altering organic nitrogen concentration. The data revealed several pathways for chemoautotrophy and the secretion of recalcitrant dissolved organic carbon (RDOC) from CO2, with bacteria and archaea potentially sequestering particulate organic matter (POM) via the production of RDOC. These findings provide insights into the diversity and function of prokaryotes in suspended and sinking particles and their role in organic carbon/nitrogen export in the Southern Ocean. IMPORTANCE The biological carbon pump is crucial for the export of particulate organic matter in the ocean. Recent studies on marine microbes have shown the profound influence of bacteria and archaea as regulators of particulate organic matter export. Yet, despite the importance of the Southern Ocean as a carbon sink, we lack comparable insights regarding microbial contributions. This study provides the first insights regarding prokaryotic contributions to particulate organic matter export in the Southern Ocean. We reveal evidence that prokaryotic communities in suspended and sinking particle fractions harbor widespread genomic potential for mediating particulate organic matter export. The results substantially enhance our understanding of the role played by microorganisms in regulating particulate organic matter export in suspended and sinking marine fractions in the Southern Ocean.

RevDate: 2023-04-21

Roux S, Camargo AP, Coutinho FH, et al (2023)

iPHoP: An integrated machine learning framework to maximize host prediction for metagenome-derived viruses of archaea and bacteria.

PLoS biology, 21(4):e3002083 pii:PBIOLOGY-D-22-01906 [Epub ahead of print].

The extraordinary diversity of viruses infecting bacteria and archaea is now primarily studied through metagenomics. While metagenomes enable high-throughput exploration of the viral sequence space, metagenome-derived sequences lack key information compared to isolated viruses, in particular host association. Different computational approaches are available to predict the host(s) of uncultivated viruses based on their genome sequences, but thus far individual approaches are limited either in precision or in recall, i.e., for a number of viruses they yield erroneous predictions or no prediction at all. Here, we describe iPHoP, a two-step framework that integrates multiple methods to reliably predict host taxonomy at the genus rank for a broad range of viruses infecting bacteria and archaea, while retaining a low false discovery rate. Based on a large dataset of metagenome-derived virus genomes from the IMG/VR database, we illustrate how iPHoP can provide extensive host prediction and guide further characterization of uncultivated viruses.

RevDate: 2023-04-21

Zhang Z, S Fusco (2023)

Editorial: New insights into the genetic mechanisms of thermophilic archaea.

Frontiers in microbiology, 14:1185784.

RevDate: 2023-04-21

Zhang CJ, Chen YL, Sun YH, et al (2021)

Diversity, metabolism and cultivation of archaea in mangrove ecosystems.

Marine life science & technology, 3(2):252-262.

Mangroves comprise a globally significant intertidal ecosystem that contains a high diversity of microorganisms, including fungi, bacteria and archaea. Archaea is a major domain of life that plays important roles in biogeochemical cycles in these ecosystems. In this review, the potential roles of archaea in mangroves are briefly highlighted. Then, the diversity and metabolism of archaeal community of mangrove ecosystems across the world are summarized and Bathyarchaeota, Euryarchaeota, Thaumarchaeota, Woesearchaeota, and Lokiarchaeota are confirmed as the most abundant and ubiquitous archaeal groups. The metabolic potential of these archaeal groups indicates their important ecological function in carbon, nitrogen and sulfur cycling. Finally, some cultivation strategies that could be applied to uncultivated archaeal lineages from mangrove wetlands are suggested, including refinements to traditional cultivation methods based on genomic and transcriptomic information, and numerous innovative cultivation techniques such as single-cell isolation and high-throughput culturing (HTC). These cultivation strategies provide more opportunities to obtain previously uncultured archaea.

RevDate: 2023-04-18

Nikonov OS, Nikonova EY, Tarabarova AG, et al (2023)

Recognition of γ-Subunit by β-Subunit in Translation Initiation Factor 2. Stabilization of the GTP-Bound State of I/F 2 in Archaea and Eukaryotes.

Biochemistry. Biokhimiia, 88(2):221-230.

Eukaryotic and archaeal translation initiation factor 2 (e/aIF2) functions as a heterotrimeric complex. It consists of three subunits (α, β, γ). α- and β-subunits are bound to γ-subunit by hydrogen bonds and van der Waals interactions, but do not contact each other. Although main functions of the factor are performed by the γ-subunit, reliable formation of αγ and βγ complexes is necessary for its proper functioning. In this work, we introduced mutations in the recognition part of the βγ interface and showed that hydrophobic effect plays a crucial role in the recognition of subunits both in eukaryotes and archaea. Shape and properties of the groove on the surface of γ-subunit facilitates transition of the disordered recognition part of the β-subunit into an α-helix containing approximately the same number of residues in archaea and eukaryotes. In addition, based on the newly obtained data, it was concluded that in archaea and eukaryotes, transition of the γ-subunit to the active state leads to additional contact between the region of switch 1 and C-terminal part of the β-subunit, which stabilizes helical conformation of the switch.

RevDate: 2023-04-19

Hu H, Natarajan VP, F Wang (2021)

Towards enriching and isolation of uncultivated archaea from marine sediments using a refined combination of conventional microbial cultivation methods.

Marine life science & technology, 3(2):231-242.

UNLABELLED: The archaea that can be readily cultivated in the laboratory are only a small fraction of the total diversity that exists in nature. Although molecular ecology methods, such as metagenomic sequencing, can provide valuable information independent of cell cultivation, it is only through cultivation-based experiments that they may be fully characterized, both for their physiological and ecological properties. Here, we report our efforts towards enriching and isolation of uncultivated archaea from marine sediments using a refined combination of conventional microbial cultivation methods. Initially, cells were retrieved from the sediment samples through a cell extraction procedure and the sediment-free mixed cells were then divided into different size-range fractions by successive filtration through 0.8 µm, 0.6 µm and 0.2 µm membranes. Archaeal 16S rRNA gene analyses indicated noticeable retention of different archaeal groups in different fractions. For each fraction, supplementation with a variety of defined substrates (e.g., methane, sulfate, and lignin) and stepwise dilutions led to highly active enrichment cultures of several archaeal groups with Bathyarchaeota most prominently enriched. Finally, using a roll-bottle technique, three co-cultures consisting of Bathyarchaeota (subgroup-8) and a bacterial species affiliated with either Pseudomonas or Glutamicibacter were obtained. Our results demonstrate that a combination of cell extraction, size fractionation, and roll-bottle isolation methods could be a useful protocol for the successful enrichment and isolation of numerous slow-growing archaeal groups from marine sediments.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42995-021-00092-0.

RevDate: 2023-04-19

Cui HL, ML Dyall-Smith (2021)

Cultivation of halophilic archaea (class Halobacteria) from thalassohaline and athalassohaline environments.

Marine life science & technology, 3(2):243-251.

UNLABELLED: As a group, the halophilic archaea (class Halobacteria) are the most salt-requiring and salt-resistant microorganisms within the domain Archaea. Halophilic archaea flourish in thalassohaline and athalassohaline environments and require over 100-150 g/L NaCl for growth and structural stability. Natural hypersaline environments vary in salt concentration, chemical composition and pH, and occur in climates ranging from tropical to polar and even under-sea. Accordingly, their resident haloarchaeal species vary enormously, as do their individual population compositions and community structures. These diverse halophilic archaeal strains are precious resources for theoretical and applied research but assessing their taxonomic and metabolic novelty and diversity in natural environments has been technically difficult up until recently. Environmental DNA-based high-throughput sequencing technology has now matured sufficiently to allow inexpensive recovery of massive amounts of sequence data, revealing the distribution and community composition of halophilic archaea in different hypersaline environments. While cultivation of haloarchaea is slow and tedious, and only recovers a fraction of the natural diversity, it is the conventional means of describing new species, and provides strains for detailed study. As of the end of May 2020, the class Halobacteria contains 71 genera and 275 species, 49.8% of which were first isolated from the marine salt environment and 50.2% from the inland salt environment, indicating that both thalassohaline and athalassohaline environments contain diverse halophilic archaea. However, there remain taxa that have not yet been isolated in pure culture, such as the nanohaloarchaea, which are widespread in the salt environment and may be one of the hot spots in the field of halophilic archaea research in the future. In this review, we focus on the cultivation strategies that have been used to isolate extremely halophilic archaea and point out some of the pitfalls and challenges.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42995-020-00087-3.

RevDate: 2023-04-17

Cerna-Vargas JP, Gumerov VM, Krell T, et al (2023)

Amine recognizing domain in diverse receptors from bacteria and archaea evolved from the universal amino acid sensor.

bioRxiv : the preprint server for biology pii:2023.04.06.535858.

Bacteria contain many different receptor families that sense different signals permitting an optimal adaptation to the environment. A major limitation in microbiology is the lack of information on the signal molecules that activate receptors. Due to a significant sequence divergence, the signal recognized by sensor domains is only poorly reflected in overall sequence identity. Biogenic amines are of central physiological relevance for microorganisms and serve for example as substrates for aerobic and anaerobic growth, neurotransmitters or osmoprotectants. Based on protein structural information and sequence analysis, we report here the identification of a sequence motif that is specific for amine-sensing dCache sensor domains (dCache_1AM). These domains were identified in more than 13,000 proteins from 8,000 bacterial and archaeal species. dCache_1AM containing receptors were identified in all major receptor families including sensor kinases, chemoreceptors, receptors involved in second messenger homeostasis and Ser/Thr phosphatases. The screening of compound libraries and microcalorimetric titrations of selected dCache_1AM domains confirmed their capacity to specifically bind amines. Mutants in the amine binding motif or domains that contain a single mismatch in the binding motif, had either no or a largely reduced affinity for amines, illustrating the specificity of this motif. We demonstrate that the dCache_1AM domain has evolved from the universal amino acid sensing domain, providing novel insight into receptor evolution. Our approach enables precise "wet"-lab experiments to define the function of regulatory systems and thus holds a strong promise to address an important bottleneck in microbiology: the identification of signals that stimulate numerous receptors.

RevDate: 2023-04-17

Lach J, Strapagiel D, Matera-Witkiewicz A, et al (2023)

Draft genomes of halophilic Archaea strains isolated from brines of the Carpathian Foreland, Poland.

Journal of genomics, 11:20-25.

Halophilic Archaea are a unique group of microorganisms living in saline environments. They constitute a complex group whose biodiversity has not been thoroughly studied. Here, we report three draft genomes of halophilic Archaea isolated from brines, representing the genera of Halorubrum, Halopenitus, and Haloarcula. Two of these strains, Boch-26 and POP-27, were identified as members of the genera Halorubrum and Halopenitus, respectively. However, they could not be assigned to any known species because of the excessive difference in genome sequences between these strains and any other described genomes. In contrast, the third strain, Boch-26, was identified as Haloarcula hispanica. Genome lengths of these isolates ranged from 2.7 Mbp to 3.0 Mbp, and GC content was in the 63.77%-68.77% range. Moreover, functional analysis revealed biosynthetic gene clusters (BGCs) related to terpenes production in all analysed genomes and one BGC for RRE (RiPP recognition element)-dependent RiPP (post-translationally modified peptides) biosynthesis. Moreover, the obtained results enhanced the knowledge about the salt mines microbiota biodiversity as a poorly explored environment so far.

RevDate: 2023-04-17

Liang H, Song ZM, Zhong Z, et al (2023)

Genomic and metabolic analyses reveal antagonistic lanthipeptides in archaea.

Microbiome, 11(1):74.

BACKGROUND: Microbes produce diverse secondary metabolites (SMs) such as signaling molecules and antimicrobials that mediate microbe-microbe interaction. Archaea, the third domain of life, are a large and diverse group of microbes that not only exist in extreme environments but are abundantly distributed throughout nature. However, our understanding of archaeal SMs lags far behind our knowledge of those in bacteria and eukarya.

RESULTS: Guided by genomic and metabolic analysis of archaeal SMs, we discovered two new lanthipeptides with distinct ring topologies from a halophilic archaeon of class Haloarchaea. Of these two lanthipeptides, archalan α exhibited anti-archaeal activities against halophilic archaea, potentially mediating the archaeal antagonistic interactions in the halophilic niche. To our best knowledge, archalan α represents the first lantibiotic and the first anti-archaeal SM from the archaea domain.

CONCLUSIONS: Our study investigates the biosynthetic potential of lanthipeptides in archaea, linking lanthipeptides to antagonistic interaction via genomic and metabolic analyses and bioassay. The discovery of these archaeal lanthipeptides is expected to stimulate the experimental study of poorly characterized archaeal chemical biology and highlight the potential of archaea as a new source of bioactive SMs. Video Abstract.

RevDate: 2023-04-15

Cumsille A, Durán RE, Rodríguez-Delherbe A, et al (2023)

GenoVi, an open-source automated circular genome visualizer for bacteria and archaea.

PLoS computational biology, 19(4):e1010998.

The increase in microbial sequenced genomes from pure cultures and metagenomic samples reflects the current attainability of whole-genome and shotgun sequencing methods. However, software for genome visualization still lacks automation, integration of different analyses, and customizable options for non-experienced users. In this study, we introduce GenoVi, a Python command-line tool able to create custom circular genome representations for the analysis and visualization of microbial genomes and sequence elements. It is designed to work with complete or draft genomes, featuring customizable options including 25 different built-in color palettes (including 5 color-blind safe palettes), text formatting options, and automatic scaling for complete genomes or sequence elements with more than one replicon/sequence. Using a Genbank format file as the input file or multiple files within a directory, GenoVi (i) visualizes genomic features from the GenBank annotation file, (ii) integrates a Cluster of Orthologs Group (COG) categories analysis using DeepNOG, (iii) automatically scales the visualization of each replicon of complete genomes or multiple sequence elements, (iv) and generates COG histograms, COG frequency heatmaps and output tables including general stats of each replicon or contig processed. GenoVi's potential was assessed by analyzing single and multiple genomes of Bacteria and Archaea. Paraburkholderia genomes were analyzed to obtain a fast classification of replicons in large multipartite genomes. GenoVi works as an easy-to-use command-line tool and provides customizable options to automatically generate genomic maps for scientific publications, educational resources, and outreach activities. GenoVi is freely available and can be downloaded from

RevDate: 2023-04-04
CmpDate: 2023-04-04

Tang SK, Zhi XY, Zhang Y, et al (2023)

Cellular differentiation into hyphae and spores in halophilic archaea.

Nature communications, 14(1):1827.

Several groups of bacteria have complex life cycles involving cellular differentiation and multicellular structures. For example, actinobacteria of the genus Streptomyces form multicellular vegetative hyphae, aerial hyphae, and spores. However, similar life cycles have not yet been described for archaea. Here, we show that several haloarchaea of the family Halobacteriaceae display a life cycle resembling that of Streptomyces bacteria. Strain YIM 93972 (isolated from a salt marsh) undergoes cellular differentiation into mycelia and spores. Other closely related strains are also able to form mycelia, and comparative genomic analyses point to gene signatures (apparent gain or loss of certain genes) that are shared by members of this clade within the Halobacteriaceae. Genomic, transcriptomic and proteomic analyses of non-differentiating mutants suggest that a Cdc48-family ATPase might be involved in cellular differentiation in strain YIM 93972. Additionally, a gene encoding a putative oligopeptide transporter from YIM 93972 can restore the ability to form hyphae in a Streptomyces coelicolor mutant that carries a deletion in a homologous gene cluster (bldKA-bldKE), suggesting functional equivalence. We propose strain YIM 93972 as representative of a new species in a new genus within the family Halobacteriaceae, for which the name Actinoarchaeum halophilum gen. nov., sp. nov. is herewith proposed. Our demonstration of a complex life cycle in a group of haloarchaea adds a new dimension to our understanding of the biological diversity and environmental adaptation of archaea.

RevDate: 2023-04-03

Hu Y, Ma X, Li XX, et al (2023)

Natrinema caseinilyticum sp. nov., Natrinema gelatinilyticum sp. nov., Natrinema marinum sp. nov., Natrinema zhouii sp. nov., extremely halophilic archaea isolated from marine environments and a salt mine.

Extremophiles : life under extreme conditions, 27(1):9.

Four extremely halophilic archaeal strains (ZJ2[T], BND6[T], DT87[T], and YPL30[T]) were isolated from marine environments and a salt mine in China. The 16S rRNA and rpoB' gene sequence similarities among strains ZJ2[T], BND6[T], DT87[T], YPL30[T] and the current species of Natrinema were 93.2-99.3% and 89.2-95.8%, respectively. Both phylogenetic and phylogenomic analyses revealed that strains ZJ2[T], BND6[T], DT87[T], and YPL30[T] cluster with the Natrinema members. The overall genome-related indexes (ANI, isDDH, and AAI) among these four strains and the current species of genus Natrinema were 70-88%, 22-43% and 75-89%, respectively, clearly below the threshold values for species boundary. Strains ZJ2[T], BND6[T], DT87[T], and YPL30[T] could be distinguished from the related species according to differential phenotypic characteristics. The major polar lipids of the four strains were phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), sulfated mannosyl glucosyl diether (S-DGD-1), and disulfated mannosyl glucosyl diether (S2-DGD). The phenotypic, chemotaxonomic, phylogenetic and phylogenomic features indicated that strains ZJ2[T] (= CGMCC 1.18786[ T] = JCM 34918[ T]), BND6[T] (= CGMCC 1.18777[ T] = JCM 34909[ T]), DT87[T] (= CGMCC 1.18921[ T] = JCM 35420[ T]), and YPL30[T] (= CGMCC 1.15337[ T] = JCM 31113[ T]) represent four novel species of the genus Natrinema, for which the names, Natrinema caseinilyticum sp. nov., Natrinema gelatinilyticum sp. nov., Natrinema marinum sp. nov., and Natrinema zhouii sp. nov., are proposed.

RevDate: 2023-03-31

Iguchi A, Takemura Y, Danshita T, et al (2023)

Isolation and physiological properties of methanogenic archaea that degrade tetramethylammonium hydroxide.

Applied microbiology and biotechnology [Epub ahead of print].

Tetramethylammonium hydroxide (TMAH) is a known toxic chemical used in the photolithography process of semiconductor photoelectronic processes. Significant amounts of wastewater containing TMAH are discharged from electronic industries. It is therefore attractive to apply anaerobic treatment to industrial wastewater containing TMAH. In this study, a novel TMAH-degrading methanogenic archaeon was isolated from the granular sludge of a psychrophilic upflow anaerobic sludge blanket (UASB) reactor treating synthetic wastewater containing TMAH. Although the isolate (strain NY-STAYD) was phylogenetically related to Methanomethylovorans uponensis, it was the only isolated Methanomethylovorans strain capable of TMAH degradation. Strain NY-STAYD was capable of degrading methylamine compounds, similar to the previously isolated Methanomethylovorans spp. While the strain was able to grow at temperatures ranging from 15 to 37°C, the cell yield was higher at lower temperatures. The distribution of archaeal cells affiliated with the genus Methanomethylovorans in the original granular sludge was investigated by fluorescence in situ hybridization (FISH) using specific oligonucleotide probe targeting 16S rRNA. The results demonstrated that the TMAH-degrading cells associated with the genus Methanomethylovorans were not intermingled with other microorganisms but rather isolated on the granule's surface as a lone dominant archaeon. KEY POINTS: • A TMAH-degrading methanogenic Methanomethylovorans strain was isolated • This strain was the only known Methanomethylovorans isolate that can degrade TMAH • The highest cell yield of the isolate was obtained at psychrophilic conditions.

RevDate: 2023-03-31

D'Alò F, Zucconi L, Onofri S, et al (2023)

Effects of 5-year experimental warming in the Alpine belt on soil Archaea: Multi-omics approaches and prospects.

Environmental microbiology reports [Epub ahead of print].

We currently lack a predictive understanding of how soil archaeal communities may respond to climate change, particularly in Alpine areas where warming is far exceeding the global average. Here, we characterized the abundance, structure, and function of total (by metagenomics) and active soil archaea (by metatranscriptomics) after 5-year experimental field warming (+1°C) in Italian Alpine grasslands and snowbeds. Our multi-omics approach unveiled an increasing abundance of Archaea during warming in snowbeds, which was negatively correlated with the abundance of fungi (by qPCR) and micronutrients (Ca and Mg), but positively correlated with soil water content. In the snowbeds transcripts, warming resulted in the enrichment of abundances of transcription and nucleotide biosynthesis. Our study provides novel insights into possible changes in soil Archaea composition and function in the climate change scenario.

RevDate: 2023-03-31

Cisek AA, Bąk I, B Cukrowska (2023)

Improved Quantitative Real-Time PCR Protocol for Detection and Quantification of Methanogenic Archaea in Stool Samples.

Microorganisms, 11(3):.

Methanogenic archaea are an important component of the human and animal intestinal microbiota, and yet their presence is rarely reported in publications describing the subject. One of the methods of quantifying the prevalence of methanogens is quantitative real-time PCR (qPCR) of the methanogen-specific mcrA gene, and one of the possible reasons for detection failure is usually a methodology bias. Here, we refined the existing protocol by changing one of the primers and improving the conditions of the qPCR reaction. As a result, at the expense of a slightly lower yet acceptable PCR efficiency, the new assay was characterized by increased specificity and sensitivity and a wider linear detection range of 7 orders of magnitude. The lowest copy number of mcrA quantified at a frequency of 100% was 21 copies per reaction. The other validation parameters tested, such as reproducibility and linearity, also gave satisfactory results. Overall, we were able to minimize the negative impacts of primer dimerization and other cross-reactions on qPCR and increase the number of not only detectable but also quantifiable stool samples-or in this case, chicken droppings.

RevDate: 2023-03-29

Slobodkin AI, Ratnikova NM, Slobodkina GB, et al (2023)

Composition and Metabolic Potential of Fe(III)-Reducing Enrichment Cultures of Methanotrophic ANME-2a Archaea and Associated Bacteria.

Microorganisms, 11(3): pii:microorganisms11030555.

The key microbial group involved in anaerobic methane oxidation is anaerobic methanotrophic archaea (ANME). From a terrestrial mud volcano, we enriched a microbial community containing ANME-2a, using methane as an electron donor, Fe(III) oxide (ferrihydrite) as an electron acceptor, and anthraquinone-2,6-disulfonate as an electron shuttle. Ferrihydrite reduction led to the formation of a black, highly magnetic precipitate. A significant relative abundance of ANME-2a in batch cultures was observed over five subsequent transfers. Phylogenetic analysis revealed that, in addition to ANME-2a, two bacterial taxa belonging to uncultured Desulfobulbaceae and Anaerolineaceae were constantly present in all enrichments. Metagenome-assembled genomes (MAGs) of ANME-2a contained a complete set of genes for methanogenesis and numerous genes of multiheme c-type cytochromes (MHC), indicating the capability of methanotrophs to transfer electrons to metal oxides or to a bacterial partner. One of the ANME MAGs encoded respiratory arsenate reductase (Arr), suggesting the potential for a direct coupling of methane oxidation with As(V) reduction in the single microorganism. The same MAG also encoded uptake [NiFe] hydrogenase, which is uncommon for ANME-2. The MAG of uncultured Desulfobulbaceae contained genes of dissimilatory sulfate reduction, a Wood-Ljungdahl pathway for autotrophic CO2 fixation, hydrogenases, and 43 MHC. We hypothesize that uncultured Desulfobulbaceae is a bacterial partner of ANME-2a, which mediates extracellular electron transfer to Fe(III) oxide.

RevDate: 2023-03-28
CmpDate: 2023-03-24

Regueira-Iglesias A, Vázquez-González L, Balsa-Castro C, et al (2023)

In silico evaluation and selection of the best 16S rRNA gene primers for use in next-generation sequencing to detect oral bacteria and archaea.

Microbiome, 11(1):58.

BACKGROUND: Sequencing has been widely used to study the composition of the oral microbiome present in various health conditions. The extent of the coverage of the 16S rRNA gene primers employed for this purpose has not, however, been evaluated in silico using oral-specific databases. This paper analyses these primers using two databases containing 16S rRNA sequences from bacteria and archaea found in the human mouth and describes some of the best primers for each domain.

RESULTS: A total of 369 distinct individual primers were identified from sequencing studies of the oral microbiome and other ecosystems. These were evaluated against a database reported in the literature of 16S rRNA sequences obtained from oral bacteria, which was modified by our group, and a self-created oral archaea database. Both databases contained the genomic variants detected for each included species. Primers were evaluated at the variant and species levels, and those with a species coverage (SC) ≥75.00% were selected for the pair analyses. All possible combinations of the forward and reverse primers were identified, with the resulting 4638 primer pairs also evaluated using the two databases. The best bacteria-specific pairs targeted the 3-4, 4-7, and 3-7 16S rRNA gene regions, with SC levels of 98.83-97.14%; meanwhile, the optimum archaea-specific primer pairs amplified regions 5-6, 3-6, and 3-6, with SC estimates of 95.88%. Finally, the best pairs for detecting both domains targeted regions 4-5, 3-5, and 5-9, and produced SC values of 95.71-94.54% and 99.48-96.91% for bacteria and archaea, respectively.

CONCLUSIONS: Given the three amplicon length categories (100-300, 301-600, and >600 base pairs), the primer pairs with the best coverage values for detecting oral bacteria were as follows: KP_F048-OP_R043 (region 3-4; primer pair position for Escherichia coli J01859.1: 342-529), KP_F051-OP_R030 (4-7; 514-1079), and KP_F048-OP_R030 (3-7; 342-1079). For detecting oral archaea, these were as follows: OP_F066-KP_R013 (5-6; 784-undefined), KP_F020-KP_R013 (3-6; 518-undefined), and OP_F114-KP_R013 (3-6; 340-undefined). Lastly, for detecting both domains jointly they were KP_F020-KP_R032 (4-5; 518-801), OP_F114-KP_R031 (3-5; 340-801), and OP_F066-OP_R121 (5-9; 784-1405). The primer pairs with the best coverage identified herein are not among those described most widely in the oral microbiome literature. Video Abstract.

RevDate: 2023-03-23

Lynes MM, Krukenberg V, Jay ZJ, et al (2023)

Diversity and function of methyl-coenzyme M reductase-encoding archaea in Yellowstone hot springs revealed by metagenomics and mesocosm experiments.

ISME communications, 3(1):22.

Metagenomic studies on geothermal environments have been central in recent discoveries on the diversity of archaeal methane and alkane metabolism. Here, we investigated methanogenic populations inhabiting terrestrial geothermal features in Yellowstone National Park (YNP) by combining amplicon sequencing with metagenomics and mesocosm experiments. Detection of methyl-coenzyme M reductase subunit A (mcrA) gene amplicons demonstrated a wide diversity of Mcr-encoding archaea inhabit geothermal features with differing physicochemical regimes across YNP. From three selected hot springs we recovered twelve Mcr-encoding metagenome assembled genomes (MAGs) affiliated with lineages of cultured methanogens as well as Candidatus (Ca.) Methanomethylicia, Ca. Hadesarchaeia, and Archaeoglobi. These MAGs encoded the potential for hydrogenotrophic, aceticlastic, hydrogen-dependent methylotrophic methanogenesis, or anaerobic short-chain alkane oxidation. While Mcr-encoding archaea represent minor fractions of the microbial community of hot springs, mesocosm experiments with methanogenic precursors resulted in the stimulation of methanogenic activity and the enrichment of lineages affiliated with Methanosaeta and Methanothermobacter as well as with uncultured Mcr-encoding archaea including Ca. Korarchaeia, Ca. Nezhaarchaeia, and Archaeoglobi. We revealed that diverse Mcr-encoding archaea with the metabolic potential to produce methane from different precursors persist in the geothermal environments of YNP and can be enriched under methanogenic conditions. This study highlights the importance of combining environmental metagenomics with laboratory-based experiments to expand our understanding of uncultured Mcr-encoding archaea and their potential impact on microbial carbon transformations in geothermal environments and beyond.

RevDate: 2023-03-17

Chen J, Li Y, Zhong C, et al (2023)

Genomic Insights into Niche Partitioning across Sediment Depth among Anaerobic Methane-Oxidizing Archaea in Global Methane Seeps.

mSystems [Epub ahead of print].

Marine sediments are important methane reservoirs. Methane efflux from the seabed is significantly restricted by anaerobic methanotrophic (ANME) archaea through a process known as anaerobic oxidation of methane (AOM). Different clades of ANME archaea occupy distinct niches in methane seeps, but their underlying molecular mechanisms still need to be fully understood. To provide genetic explanations for the niche partitioning of ANME archaea, we applied comparative genomic analysis to ANME archaeal genomes retrieved from global methane seeps. Our results showed that ANME-2 archaea are more prevalent than ANME-1 archaea in shallow sediments because they carry genes that encode a significantly higher number of outer membrane multiheme c-type cytochromes and flagellar proteins. These features make ANME-2 archaea perform direct interspecies electron transfer better and benefit more from electron acceptors in AOM. Besides, ANME-2 archaea carry genes that encode extra peroxidase compared to ANME-1 archaea, which may lead to ANME-2 archaea better tolerating oxygen toxicity. In contrast, ANME-1 archaea are more competitive in deep layers than ANME-2 archaea because they carry extra genes (mtb and mtt) for methylotrophic methanogenesis and a significantly higher number of frh and mvh genes for hydrogenotrophic methanogenesis. Additionally, ANME-1 archaea carry exclusive genes (sqr, TST, and mddA) involved in sulfide detoxification compared to ANME-2 archaea, leading to stronger sulfide tolerance. Overall, this study reveals the genomic mechanisms shaping the niche partitioning among ANME archaea in global methane seeps. IMPORTANCE Anaerobic methanotrophic (ANME) archaea are important methanotrophs in marine sediment, controlling the flux of biologically generated methane, which plays an essential role in the marine carbon cycle and climate change. So far, no strain of this lineage has been isolated in pure culture, which makes metagenomics one of the fundamental approaches to reveal their metabolic potential. Although the niche partitioning of ANME archaea was frequently reported in different studies, whether this pattern was consistent in global methane seeps had yet to be verified, and little was known about the genetic mechanisms underlying it. Here, we reviewed and analyzed the community structure of ANME archaea in global methane seeps and indicated that the niche partitioning of ANME archaea was statistically supported. Our comparative genomic analysis indicated that the capabilities of interspecies electron transfer, methanogenesis, and the resistance of oxygen and hydrogen sulfide could be critical in defining the distribution of ANME archaea in methane seep sediment.

RevDate: 2023-03-15

Adlung N, S Scheller (2023)

Application of the Fluorescence-Activating and Absorption-Shifting Tag (FAST) for Flow Cytometry in Methanogenic Archaea.

Applied and environmental microbiology [Epub ahead of print].

Methane-producing archaea play a crucial role in the global carbon cycle and are used for biotechnological fuel production. Methanogenic model organisms such as Methanococcus maripaludis and Methanosarcina acetivorans have been biochemically characterized and can be genetically engineered by using a variety of existing molecular tools. The anaerobic lifestyle and autofluorescence of methanogens, however, restrict the use of common fluorescent reporter proteins (e.g., GFP and derivatives), which require oxygen for chromophore maturation. Recently, the use of a novel oxygen-independent fluorescent activation and absorption-shifting tag (FAST) was demonstrated with M. maripaludis. Similarly, we now describe the use of the tandem activation and absorption-shifting tag protein 2 (tdFAST2), which fluoresces when the cell-permeable fluorescent ligand (fluorogen) 4-hydroxy-3,5-dimethoxybenzylidene rhodanine (HBR-3,5DOM) is present. Expression of tdFAST2 in M. acetivorans and M. maripaludis is noncytotoxic and tdFAST2:HBR-3,5DOM fluorescence is clearly distinguishable from the autofluorescence. In flow cytometry experiments, mixed methanogen cultures can be distinguished, thereby allowing for the possibility of high-throughput investigations of the characteristic dynamics within single and mixed cultures. IMPORTANCE Methane-producing archaea play an essential role in the global carbon cycle and demonstrate great potential for various biotechnological applications, e.g., biofuel production, carbon dioxide capture, and electrochemical systems. Oxygen sensitivity and high autofluorescence hinder the use of common fluorescent proteins for studying methanogens. By using tdFAST2:HBR-3,5DOM fluorescence, which functions under anaerobic conditions and is distinguishable from the autofluorescence, real-time reporter studies and high-throughput investigation of the mixed culture dynamics of methanogens via flow cytometry were made possible. This will further help accelerate the sustainable exploitation of methanogens.

RevDate: 2023-03-13

Li D, Ren Z, Zhou Y, et al (2023)

Comammox Nitrospira and Ammonia-Oxidizing Archaea Are Dominant Ammonia Oxidizers in Sediments of an Acid Mine Lake Containing High Ammonium Concentrations.

Applied and environmental microbiology [Epub ahead of print].

Exploring nitrifiers in extreme environments is vital to expanding our understanding of nitrogen cycle and microbial diversity. This study presents that complete ammonia oxidation (comammox) Nitrospira, together with acidophilic ammonia-oxidizing archaea (AOA), dominate in the nitrifying guild in sediments of an acid mine lake (AML). The lake water was characterized by acidic pH below 5 with a high ammonium concentration of 175 mg-N/liter, which is rare on the earth. Nitrification was active in sediments with a maximum nitrate production potential of 70.5 μg-N/(g-dry weight [dw] day) for mixed sediments. Quantitative PCR assays determined that in AML sediments, comammox Nitrospira and AOA amoA genes had relative abundances of 52% and 41%, respectively, among the total amoA genes. Further assays with 16S rRNA and amoA gene amplicon sequencing and metagenomics confirmed their dominance and revealed that the comammox Nitrospira found in sediments belonged to comammox Nitrospira clade A.2. Metagenomic binning retrieved a metagenome-assembled genome (MAG) of the comammox Nitrospira from sediments (completeness = 96.76%), and phylogenomic analysis suggested that it was a novel comammox Nitrospira. Comparative genomic investigation revealed that this comammox Nitrospira contained diverse metal resistance genes and an acidophile-affiliated F-type ATPase. Moreover, it had a more diverse genomic characteristic on nitrogen metabolism than the AOA in sediments and canonical AOB did. The results suggest that comammox Nitrospira is a versatile nitrifier that can adapt to acidic environments even with high ammonium concentrations. IMPORTANCE Ammonia-oxidizing archaea (AOA) was previously considered the sole dominant ammonia oxidizer in acidic environments. This study, however, found that complete ammonia oxidation (comammox) Nitrospira was also a dominant ammonia oxidizer in the sediments of an acidic mine lake, which had an acidic pH < 5 and a high ammonium concentration of 175 mg-N/liter. In combination with average nucleotide identity analysis, phylogenomic analysis suggested it is a novel strain of comammox Nitrospira. Moreover, the adaption of comammox Nitrospira to the acidic lake had been comprehensively investigated based on genome-centric metagenomic approaches. The outcomes of this study significantly expand our understanding of the diversity and adaptability of ammonia oxidizers in the acidic environments.

RevDate: 2023-03-13

Cheng H, Yang Y, He Y, et al (2023)

Spatio-temporal variations of activity of nitrate-driven anaerobic oxidation of methane and community structure of Candidatus Methanoperedens-like archaea in sediment of Wuxijiang river.

Chemosphere, 324:138295 pii:S0045-6535(23)00562-3 [Epub ahead of print].

Nitrate-driven anaerobic oxidation of methane (AOM), catalyzing by Candidatus Methanoperedens-like archaea, is a new addition in the global CH4 cycle. This AOM process acts as a novel pathway for CH4 emission reduction in freshwater aquatic ecosystems; however, its quantitative importance and regulatory factors in riverine ecosystems are nearly unknown. Here, we examined the spatio-temporal changes of the communities of Methanoperedens-like archaea and nitrate-driven AOM activity in sediment of Wuxijiang River, a mountainous river in China. These archaeal community composition varied significantly among reaches (upper, middle, and lower reaches) and between seasons (winter and summer), but their mcrA gene diversity showed no significant spatial or temporal variations. The copy numbers of Methanoperedens-like archaeal mcrA genes were 1.32 × 10[5]-2.47 × 10[7] copies g[-1] (dry weight), and the activity of nitrate-driven AOM was 0.25-1.73 nmol CH4 g[-1] (dry weight) d[-1], which could potentially reduce 10.3% of CH4 emissions from rivers. Significant spatio-temporal variations of mcrA gene abundance and nitrate-driven AOM activity were found. Both the gene abundance and activity increased significantly from upper to lower reaches in both seasons, and were significantly higher in sediment collected in summer than in winter. In addition, the variations of Methanoperedens-like archaeal communities and nitrate-driven AOM activity were largely impacted by the sediment temperature, NH4[+] and organic carbon contents. Taken together, both time and space scales need to be considered for better evaluating the quantitative importance of nitrate-driven AOM in reducing CH4 emissions from riverine ecosystems.

RevDate: 2023-03-09

Wan XS, Hou L, Kao SJ, et al (2023)

Pathways of N2O production by marine ammonia-oxidizing archaea determined from dual-isotope labeling.

Proceedings of the National Academy of Sciences of the United States of America, 120(11):e2220697120.

The ocean is a net source of the greenhouse gas and ozone-depleting substance, nitrous oxide (N2O), to the atmosphere. Most of that N2O is produced as a trace side product during ammonia oxidation, primarily by ammonia-oxidizing archaea (AOA), which numerically dominate the ammonia-oxidizing community in most marine environments. The pathways to N2O production and their kinetics, however, are not completely understood. Here, we use [15]N and [18]O isotopes to determine the kinetics of N2O production and trace the source of nitrogen (N) and oxygen (O) atoms in N2O produced by a model marine AOA species, Nitrosopumilus maritimus. We find that during ammonia oxidation, the apparent half saturation constants of nitrite and N2O production are comparable, suggesting that both processes are enzymatically controlled and tightly coupled at low ammonia concentrations. The constituent atoms in N2O are derived from ammonia, nitrite, O2, and H2O via multiple pathways. Ammonia is the primary source of N atoms in N2O, but its contribution varies with ammonia to nitrite ratio. The ratio of [45]N2O to [46]N2O (i.e., single or double labeled N) varies with substrate ratio, leading to widely varying isotopic signatures in the N2O pool. O2 is the primary source for O atoms. In addition to the previously demonstrated hybrid formation pathway, we found a substantial contribution by hydroxylamine oxidation, while nitrite reduction is an insignificant source of N2O. Our study highlights the power of dual [15]N-[18]O isotope labeling to disentangle N2O production pathways in microbes, with implications for interpretation of pathways and regulation of marine N2O sources.

RevDate: 2023-03-07

Mei R, Kaneko M, Imachi H, et al (2023)

The origin and evolution of methanogenesis and Archaea are intertwined.

PNAS nexus, 2(2):pgad023.

Methanogenesis has been widely accepted as an ancient metabolism, but the precise evolutionary trajectory remains hotly debated. Disparate theories exist regarding its emergence time, ancestral form, and relationship with homologous metabolisms. Here, we report the phylogenies of anabolism-involved proteins responsible for cofactor biosynthesis, providing new evidence for the antiquity of methanogenesis. Revisiting the phylogenies of key catabolism-involved proteins further suggests that the last Archaea common ancestor (LACA) was capable of versatile H2-, CO2-, and methanol-utilizing methanogenesis. Based on phylogenetic analyses of the methyl/alkyl-S-CoM reductase family, we propose that, in contrast to current paradigms, substrate-specific functions emerged through parallel evolution traced back to a nonspecific ancestor, which likely originated from protein-free reactions as predicted from autocatalytic experiments using cofactor F430. After LACA, inheritance/loss/innovation centered around methanogenic lithoautotrophy coincided with ancient lifestyle divergence, which is clearly reflected by genomically predicted physiologies of extant archaea. Thus, methanogenesis is not only a hallmark metabolism of Archaea, but the key to resolve the enigmatic lifestyle that ancestral archaea took and the transition that led to physiologies prominent today.

RevDate: 2023-02-26

Zheng P, Zhang Q, Zou J, et al (2023)

A new strategy for the enrichment of ammonia-oxidizing archaea in wastewater treatment systems: The positive role of quorum-sensing signaling molecules.

The Science of the total environment pii:S0048-9697(23)01001-X [Epub ahead of print].

Ammonia-oxidizing archaea (AOA) play an important role in natural nitrogen cycle, but are difficult to be enriched in wastewater treatment systems. In this experiment, under ambient temperature and high dissolved oxygen, different types of acyl-homoserine lactones (C6-HSL, C8-HSL, C10-HSL, C14-HSL and 3-oxo-C14-HSL) were added to five wastewater nitrification systems to achieve AOA enrichment. Results showed that AOA couldn't be detected in the blank group without the addition of signaling molecules, while the AOA could be detected in all the reactors with the addition. The enrichment effect of AOA was not obvious with added 100 or 200 nmol/L signaling molecules, while the enrichment effect was both obvious with added C8-HSL of 400 nmol/L and C10-HSL of 800 nmol/L. And relative abundance of AOA increased from undetected in the control group to 1.10 % and 0.96 %, respectively. The exogenous signaling molecules may provide new view for AOA enrichment in wastewater treatment systems.

RevDate: 2023-02-26

Ngcobo PE, Nkosi BVZ, Chen W, et al (2023)

Evolution of Cytochrome P450 Enzymes and Their Redox Partners in Archaea.

International journal of molecular sciences, 24(4):.

Cytochrome P450 monooxygenases (CYPs/P450s) and their redox partners, ferredoxins, are ubiquitous in organisms. P450s have been studied in biology for over six decades owing to their distinct catalytic activities, including their role in drug metabolism. Ferredoxins are ancient proteins involved in oxidation-reduction reactions, such as transferring electrons to P450s. The evolution and diversification of P450s in various organisms have received little attention and no information is available for archaea. This study is aimed at addressing this research gap. Genome-wide analysis revealed 1204 P450s belonging to 34 P450 families and 112 P450 subfamilies, where some families and subfamilies are expanded in archaea. We also identified 353 ferredoxins belonging to the four types 2Fe-2S, 3Fe-4S, 7Fe-4S and 2[4Fe-4S] in 40 archaeal species. We found that bacteria and archaea shared the CYP109, CYP147 and CYP197 families, as well as several ferredoxin subtypes, and that these genes are co-present on archaeal plasmids and chromosomes, implying the plasmid-mediated lateral transfer of these genes from bacteria to archaea. The absence of ferredoxins and ferredoxin reductases in the P450 operons suggests that the lateral transfer of these genes is independent. We present different scenarios for the evolution and diversification of P450s and ferredoxins in archaea. Based on the phylogenetic analysis and high affinity to diverged P450s, we propose that archaeal P450s could have diverged from CYP109, CYP147 and CYP197. Based on this study's results, we propose that all archaeal P450s are bacterial in origin and that the original archaea had no P450s.

RevDate: 2023-02-24

Kisly I, T Tamm (2023)

Archaea/eukaryote-specific ribosomal proteins - guardians of a complex structure.

Computational and structural biotechnology journal, 21:1249-1261.

In three domains of life, proteins are synthesized by large ribonucleoprotein particles called ribosomes. All ribosomes are composed of ribosomal RNAs (rRNA) and numerous ribosomal proteins (r-protein). The three-dimensional shape of ribosomes is mainly defined by a tertiary structure of rRNAs. In addition, rRNAs have a major role in decoding the information carried by messenger RNAs and catalyzing the peptide bond formation. R-proteins are essential for shaping the network of interactions that contribute to a various aspects of the protein synthesis machinery, including assembly of ribosomes and interaction of ribosomal subunits. Structural studies have revealed that many key components of ribosomes are conserved in all life domains. Besides the core structure, ribosomes contain domain-specific structural features that include additional r-proteins and extensions of rRNA and r-proteins. This review focuses specifically on those r-proteins that are found only in archaeal and eukaryotic ribosomes. The role of these archaea/eukaryote specific r-proteins in stabilizing the ribosome structure is discussed. Several examples illustrate their functions in the formation of the internal network of ribosomal subunits and interactions between the ribosomal subunits. In addition, the significance of these r-proteins in ribosome biogenesis and protein synthesis is highlighted.

RevDate: 2023-02-23

Dodsworth JA, O Prakash (2023)

International Committee on Systematics of Prokaryotes: subcommittee on the taxonomy of methanogenic archaea. Minutes of the closed, online meetings held 24 September 2020 and 8 October 2020.

International journal of systematic and evolutionary microbiology, 73(2):.

RevDate: 2023-02-23

Cheng X, Xiang X, Yun Y, et al (2023)

Archaea and their interactions with bacteria in a karst ecosystem.

Frontiers in microbiology, 14:1068595.

Karst ecosystems are widely distributed around the world, accounting for 15-20% of the global land area. However, knowledge on microbial ecology of these systems does not match with their global importance. To close this knowledge gap, we sampled three niches including weathered rock, sediment, and drip water inside the Heshang Cave and three types of soils overlying the cave (forest soil, farmland soil, and pristine karst soil). All these samples were subjected to high-throughput sequencing of V4-V5 region of 16S rRNA gene and analyzed with multivariate statistical analysis. Overall, archaeal communities were dominated by Thaumarchaeota, whereas Actinobacteria dominated bacterial communities. Thermoplasmata, Nitrosopumilaceae, Aenigmarchaeales, Crossiella, Acidothermus, and Solirubrobacter were the important predictor groups inside the Heshang Cave, which were correlated to NH4 [+] availability. In contrast, Candidatus Nitrososphaera, Candidatus Nitrocosmicus, Thaumarchaeota Group 1.1c, and Pseudonocardiaceae were the predictors outside the cave, whose distribution was correlated with pH, Ca[2+], and NO2 [-]. Tighter network structures were found in archaeal communities than those of bacteria, whereas the topological properties of bacterial networks were more similar to those of total prokaryotic networks. Both chemolithoautotrophic archaea (Candidatus Methanoperedens and Nitrosopumilaceae) and bacteria (subgroup 7 of Acidobacteria and Rokubacteriales) were the dominant keystone taxa within the co-occurrence networks, potentially playing fundamental roles in obtaining energy under oligotrophic conditions and thus maintaining the stability of the cave ecosystem. To be noted, all the keystone taxa of karst ecosystems were related to nitrogen cycling, which needs further investigation, particularly the role of archaea. The predicted ecological functions in karst soils mainly related to carbohydrate metabolism, biotin metabolism, and synthesis of fatty acid. Our results offer new insights into archaeal ecology, their potential functions, and archaeal interactions with bacteria, which enhance our understanding about the microbial dark matter in the subsurface karst ecosystems.

RevDate: 2023-02-23

Gios E, Mosley OE, Weaver L, et al (2023)

Ultra-small bacteria and archaea exhibit genetic flexibility towards groundwater oxygen content, and adaptations for attached or planktonic lifestyles.

ISME communications, 3(1):13.

Aquifers are populated by highly diverse microbial communities, including unusually small bacteria and archaea. The recently described Patescibacteria (or Candidate Phyla Radiation) and DPANN radiation are characterized by ultra-small cell and genomes sizes, resulting in limited metabolic capacities and probable dependency on other organisms to survive. We applied a multi-omics approach to characterize the ultra-small microbial communities over a wide range of aquifer groundwater chemistries. Results expand the known global range of these unusual organisms, demonstrate the wide geographical range of over 11,000 subsurface-adapted Patescibacteria, Dependentiae and DPANN archaea, and indicate that prokaryotes with ultra-small genomes and minimalistic metabolism are a characteristic feature of the terrestrial subsurface. Community composition and metabolic activities were largely shaped by water oxygen content, while highly site-specific relative abundance profiles were driven by a combination of groundwater physicochemistries (pH, nitrate-N, dissolved organic carbon). We provide insights into the activity of ultra-small prokaryotes with evidence that they are major contributors to groundwater community transcriptional activity. Ultra-small prokaryotes exhibited genetic flexibility with respect to groundwater oxygen content, and transcriptionally distinct responses, including proportionally greater transcription invested into amino acid and lipid metabolism and signal transduction in oxic groundwater, along with differences in taxa transcriptionally active. Those associated with sediments differed from planktonic counterparts in species composition and transcriptional activity, and exhibited metabolic adaptations reflecting a surface-associated lifestyle. Finally, results showed that groups of phylogenetically diverse ultra-small organisms co-occurred strongly across sites, indicating shared preferences for groundwater conditions.

RevDate: 2023-02-22

Zhang Q, Chen M, Leng Y, et al (2023)

Organic substitution stimulates ammonia oxidation-driven N2O emissions by distinctively enriching keystone species of ammonia-oxidizing archaea and bacteria in tropical arable soils.

The Science of the total environment pii:S0048-9697(23)00799-4 [Epub ahead of print].

Partial organic substitution (POS) is pivotal in enhancing soil productivity and changing nitrous oxide (N2O) emissions by profoundly altering soil nitrogen (N) cycling, where ammonia oxidation is a fundamental core process. However, the regulatory mechanisms of N2O production by ammonia oxidizers at the microbial community level under POS regimes remain unclear. This study explored soil ammonia oxidation and related N2O production, further building an understanding of the correlations between ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) activity and community structure in tropical arable soils under four-year field management regimes (CK, without fertilizer N; N, with only inorganic N; M1N1, with 1/2 organic N + 1/2 inorganic N; M1N2, with 1/3 organic N + 2/3 inorganic N). AOA contributed more to potential ammonia oxidation (PAO) than AOB across all treatments. In comparison with CK, N treatment had no obvious effects on PAO and lowered related N2O emissions by decreasing soil pH and downregulating the abundance of AOA- and AOB-amoA. POS regimes significantly enhanced PAO and N2O emissions relative to N treatment by promoting the abundances and contributions of AOA and AOB. The stimulated AOA-dominated N2O production under M1N1 was correlated with promoted development of Nitrososphaera. By contrast, the increased AOB-dominated N2O production under M1N2 was linked to the enhanced development of Nitrosospira multiformis. Our study suggests organic substitutions with different proportions of inorganic and organic N distinctively regulate the development of specific species of ammonia oxidizers to increase associated N2O emissions. Accordingly, appropriate options should be adopted to reduce environmental risks under POS regimes in tropical croplands.

RevDate: 2023-02-16

Diao M, Balkema C, Muñoz MS, et al (2023)

Succession of bacteria and archaea involved in the nitrogen cycle of a seasonally stratified lake.

FEMS microbiology letters pii:7043454 [Epub ahead of print].

Human-driven changes affect nutrient inputs, oxygen solubility and the hydrodynamics of lakes, which affect biogeochemical cycles mediated by microbial communities. However, information on the succession of microbes involved in nitrogen cycling in seasonally stratified lakes is still incomplete. Here, we investigated the succession of nitrogen-transforming microorganisms in Lake Vechten over 19 months, combining 16S rRNA gene amplicon sequencing and quantification of functional genes. Ammonia-oxidizing archaea (AOA) and bacteria (AOB) and anammox bacteria were abundant in the sediment during winter, accompanied by nitrate in the water column. Nitrogen-fixing bacteria and denitrifying bacteria emerged in the water column in spring when nitrate was gradually depleted. Denitrifying bacteria containing nirS genes were exclusively present in the anoxic hypolimnion. During summer stratification, abundances of AOA, AOB and anammox bacteria decreased sharply in the sediment, and ammonium accumulated in hypolimnion. After lake mixing during fall turnover, abundances of AOA, AOB and anammox bacteria increased and ammonium was oxidized to nitrate. Hence, nitrogen-transforming microorganisms in Lake Vechten displayed a pronounced seasonal succession, which was strongly determined by the seasonal stratification pattern. These results imply that changes in stratification and vertical mixing induced by global warming are likely to alter the nitrogen cycle of seasonally stratified lakes.

RevDate: 2023-02-16

Akpudo YM, Bezuidt OK, TP Makhalanyane (2023)

Metagenome-Assembled Genomes of Four Southern Ocean Archaea Harbor Multiple Genes Linked to Polyethylene Terephthalate and Polyhydroxybutyrate Plastic Degradation.

Microbiology resource announcements [Epub ahead of print].

Here, we present four archaeal metagenome-assembled genomes (MAGs) (three Thaumarchaeota MAGs and one Thermoplasmatota MAG) from a polar upwelling zone in the Southern Ocean. These archaea harbor putative genes encoding enzymes such as polyethylene terephthalate (PET) hydrolases (PETases) and polyhydroxybutyrate (PHB) depolymerases, which are associated with microbial degradation of PET and PHB plastics.

RevDate: 2023-02-15

Filée J, Becker HF, Mellottee L, et al (2023)

Bacterial origins of thymidylate metabolism in Asgard archaea and Eukarya.

Nature communications, 14(1):838.

Asgard archaea include the closest known archaeal relatives of eukaryotes. Here, we investigate the evolution and function of Asgard thymidylate synthases and other folate-dependent enzymes required for the biosynthesis of DNA, RNA, amino acids and vitamins, as well as syntrophic amino acid utilization. Phylogenies of Asgard folate-dependent enzymes are consistent with their horizontal transmission from various bacterial groups. We experimentally validate the functionality of thymidylate synthase ThyX of the cultured 'Candidatus Prometheoarchaeum syntrophicum'. The enzyme efficiently uses bacterial-like folates and is inhibited by mycobacterial ThyX inhibitors, even though the majority of experimentally tested archaea are known to use carbon carriers distinct from bacterial folates. Our phylogenetic analyses suggest that the eukaryotic thymidylate synthase, required for de novo DNA synthesis, is not closely related to archaeal enzymes and might have been transferred from bacteria to protoeukaryotes during eukaryogenesis. Altogether, our study suggests that the capacity of eukaryotic cells to duplicate their genetic material is a sum of archaeal (replisome) and bacterial (thymidylate synthase) characteristics. We also propose that recent prevalent lateral gene transfer from bacteria has markedly shaped the metabolism of Asgard archaea.

RevDate: 2023-02-14

Beltran L, Cvirkaite-Krupovic V, Roberts J, et al (2023)

Domesticated conjugation machinery promotes DNA exchange in hyperthermophilic archaea.

Biophysical journal, 122(3S1):11a.

RevDate: 2023-02-09

Wolff P, Lechner A, Droogmans L, et al (2023)

Identification of Up47 in three thermophilic archaea, one mesophilic archaeon and one hyperthermophilic bacterium.

RNA (New York, N.Y.) pii:rna.079546.122 [Epub ahead of print].

Analysis of tRNA modifications profile in several Archaea allowed to observe a novel modified uridine in the V-loop of several tRNAs from two species: Pyrococcus furiosus and Sulfolobus acidocaldarius (Wolff et al. 2020). Recently, Ohira et al. (Ohira et al. 2022) characterized 2'-phosphouridine (Up) at position 47 in tRNAs of thermophilic Sulfurisphaera tokodaii, as well as in several other archaea and thermophilic bacteria. From the presence of the gene arkI corresponding to the RNA kinase responsible for Up47 formation, they also concluded that Up47 should be present in tRNAs of other thermophilic Archaea. Re-analysis of our earlier data confirms that the unidentified residue in tRNAs of both P. furiosus and S. acidocaldarius is indeed 2'phosphouridine followed by m5C48. Moreover, we find this modification in several tRNAs of other Archaea and of the hyperthermophilic bacterium Aquifex aeolicus.


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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If you thought that the history of life could be organized into a simple tree and that genes only moved from parents to progeny, think again. Recent science has shown that sometimes genes move sideways, skipping the reproductive process, and the tree of life looks more like a tangled bush. David Quammen, a masterful science writer, explains these new findings and more. Read this book and you'll learn about the discovery of the archaea — an entirely different form of life, living right here on this planet, and not noticed until Carl Woese found them, by being among the first to use molecular tools to look at organismal relationships. R. Robbins

Electronic Scholarly Publishing
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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).


ESP now offers a much improved and expanded collection of timelines, designed to give the user choice over subject matter and dates.


Biographical information about many key scientists.

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 )