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Bibliography on: Archaea

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ESP: PubMed Auto Bibliography 25 May 2024 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: 2024-05-16

Zhang Y, Xiang Y, Yang Z, et al (2024)

Co-occurrence of dominant bacteria and methanogenic archaea and their metabolic traits in a thermophilic anaerobic digester.

Environmental science and pollution research international [Epub ahead of print].

Thermophilic anaerobic digestion (TAD) represents a promising biotechnology for both methane energy production and waste stream treatment. However, numerous critical microorganisms and their metabolic characteristics involved in this process remain unidentified due to the limitations of culturable isolates. This study investigated the phylogenetic composition and potential metabolic traits of bacteria and methanogenic archaea in a TAD system using culture-independent metagenomics. Predominant microorganisms identified in the stable phase of TAD included hydrogenotrophic methanogens (Methanothermobacter and Methanosarcina) and hydrogen-producing bacteria (Coprothermobacter, Acetomicrobium, and Defluviitoga). Nine major metagenome-assembled genomes (MAGs) associated with the dominant genera were selected to infer their metabolic potentials. Genes related to thermal resistance were widely found in all nine major MAGs, such as the molecular chaperone genes, Clp protease gene, and RNA polymerase genes, which may contribute to their predominance under thermophilic condition. Thermophilic temperatures may increase the hydrogen partial pressure of Coprothermobacter, Acetomicrobium, and Defluviitoga, subsequently altering the primary methanogenesis pathway from acetoclastic pathway to hydrogenotrophic pathway in the TAD. Consequently, genes encoding the hydrogenotrophic methanogenesis pathway were the most abundant in the recovered archaeal MAGs. The potential interaction between hydrogen-producing bacteria and hydrogenotrophic methanogens may play critical roles in TAD processes.

RevDate: 2024-05-14

Liu X, Su D, Huan H, et al (2024)

Corrigendum to "Rice-fish coculture without phosphorus addition improves paddy soil nitrogen availability by shaping ammonia-oxidizing archaea and bacteria in subtropical regions of South China" [Sci. Total Environ. 927 (2024): 171642].

RevDate: 2024-05-11

Musat F, Kjeldsen KU, Rotaru AE, et al (2024)

Archaea oxidizing alkanes through alkyl-coenzyme M reductases.

Current opinion in microbiology, 79:102486 pii:S1369-5274(24)00062-6 [Epub ahead of print].

This review synthesizes recent discoveries of novel archaea clades capable of oxidizing higher alkanes, from volatile ones like ethane to longer-chain alkanes like hexadecane. These archaea, termed anaerobic multicarbon alkane-oxidizing archaea (ANKA), initiate alkane oxidation using alkyl-coenzyme M reductases, enzymes similar to the methyl-coenzyme M reductases of methanogenic and anaerobic methanotrophic archaea (ANME). The polyphyletic alkane-oxidizing archaea group (ALOX), encompassing ANME and ANKA, harbors increasingly complex alkane degradation pathways, correlated with the alkane chain length. We discuss the evolutionary trajectory of these pathways emphasizing metabolic innovations and the acquisition of metabolic modules via lateral gene transfer. Additionally, we explore the mechanisms by which archaea couple alkane oxidation with the reduction of electron acceptors, including electron transfer to partner sulfate-reducing bacteria (SRB). The phylogenetic and functional constraints that shape ALOX-SRB associations are also discussed. We conclude by highlighting the research needs in this emerging research field and its potential applications in biotechnology.

RevDate: 2024-05-09

Kanno N, Kato S, Itoh T, et al (2022)

Resonance Raman analysis of intracellular vitamin B12 analogs in methanogenic archaea.

Analytical science advances, 3(5-6):165-173.

Methanogenic archaea (methanogens) are microorganisms that can synthesize methane. They are found in diverse environments ranging from paddy fields to animal digestive tracts to deep-sea hydrothermal vents. Investigating their distribution and physiological activity is crucial for the detailed analysis of the dynamics of greenhouse gas generation and the search for the environmental limits of life. In methanogens, cobamide cofactors (vitamin B12 analogs) play a key role in methane synthesis and carbon fixation, thus serving as a marker compound that metabolically characterizes them. Here, we report on resonance Raman detection of cobamides in methanogenic cells without destroying cells and provide structural insights into those cobamides. We succeeded in detecting cobamides in four representative methanogens Methanosarcina mazei, Methanosarcina barkeri, Methanopyrus kandleri, and Methanocaldococcus jannaschii. The former two are mesophilic, cytochrome-containing methanogens, whereas the latter two are hyperthermophilic, non-cytochrome-containing methanogens. The 532 nm-excited Raman spectra of single or multiple cells of the four species all showed resonance Raman bands of cobamides arising mainly from the corrin ring, with the most intense one at ∼1500 cm[-1]. We envision that resonance Raman microspectroscopy could be useful for in situ, nondestructive identification of methanogenic cells that produce high levels of cobamides.

RevDate: 2024-05-03

Padalko A, Nair G, FL Sousa (2024)

Fusion/fission protein family identification in Archaea.

mSystems [Epub ahead of print].

The majority of newly discovered archaeal lineages remain without a cultivated representative, but scarce experimental data from the cultivated organisms show that they harbor distinct functional repertoires. To unveil the ecological as well as evolutionary impact of Archaea from metagenomics, new computational methods need to be developed, followed by in-depth analysis. Among them is the genome-wide protein fusion screening performed here. Natural fusions and fissions of genes not only contribute to microbial evolution but also complicate the correct identification and functional annotation of sequences. The products of these processes can be defined as fusion (or composite) proteins, the ones consisting of two or more domains originally encoded by different genes and split proteins, and the ones originating from the separation of a gene in two (fission). Fusion identifications are required for proper phylogenetic reconstructions and metabolic pathway completeness assessments, while mappings between fused and unfused proteins can fill some of the existing gaps in metabolic models. In the archaeal genome-wide screening, more than 1,900 fusion/fission protein clusters were identified, belonging to both newly sequenced and well-studied lineages. These protein families are mainly associated with different types of metabolism, genetic, and cellular processes. Moreover, 162 of the identified fusion/fission protein families are archaeal specific, having no identified fused homolog within the bacterial domain. Our approach was validated by the identification of experimentally characterized fusion/fission cases. However, around 25% of the identified fusion/fission families lack functional annotations for both composite and split states, showing the need for experimental characterization in Archaea.IMPORTANCEGenome-wide fusion screening has never been performed in Archaea on a broad taxonomic scale. The overlay of multiple computational techniques allows the detection of a fine-grained set of predicted fusion/fission families, instead of rough estimations based on conserved domain annotations only. The exhaustive mapping of fused proteins to bacterial organisms allows us to capture fusion/fission families that are specific to archaeal biology, as well as to identify links between bacterial and archaeal lineages based on cooccurrence of taxonomically restricted proteins and their sequence features. Furthermore, the identification of poorly characterized lineage-specific fusion proteins opens up possibilities for future experimental and computational investigations. This approach enhances our understanding of Archaea in general and provides potential candidates for in-depth studies in the future.

RevDate: 2024-04-29
CmpDate: 2024-04-27

Dobryakova NV, Dumina MV, Zhgun AA, et al (2024)

L-Asparaginase Conjugates from the Hyperthermophilic Archaea Thermococcus sibiricus with Improved Biocatalytic Properties.

International journal of molecular sciences, 25(8):.

This study investigated the effect of polycationic and uncharged polymers (and oligomers) on the catalytic parameters and thermostability of L-asparaginase from Thermococcus sibiricus (TsA). This enzyme has potential applications in the food industry to decrease the formation of carcinogenic acrylamide during the processing of carbohydrate-containing products. Conjugation with the polyamines polyethylenimine and spermine (PEI and Spm) or polyethylene glycol (PEG) did not significantly affect the secondary structure of the enzyme. PEG contributes to the stabilization of the dimeric form of TsA, as shown by HPLC. Furthermore, neither polyamines nor PEG significantly affected the binding of the L-Asn substrate to TsA. The conjugates showed greater maximum activity at pH 7.5 and 85 °C, 10-50% more than for native TsA. The pH optima for both TsA-PEI and TsA-Spm conjugates were shifted to lower pH ranges from pH 10 (for the native enzyme) to pH 8.0. Additionally, the TsA-Spm conjugate exhibited the highest activity at pH 6.5-9.0 among all the samples. Furthermore, the temperature optimum for activity at pH 7.5 shifted from 90-95 °C to 80-85 °C for the conjugates. The thermal inactivation mechanism of TsA-PEG appeared to change, and no aggregation was observed in contrast to that of the native enzyme. This was visually confirmed and supported by the analysis of the CD spectra, which remained almost unchanged after heating the conjugate solution. These results suggest that TsA-PEG may be a more stable form of TsA, making it a potentially more suitable option for industrial use.

RevDate: 2024-04-25
CmpDate: 2024-04-25

Mukherjee D, Selvi VA, Ganguly J, et al (2024)

New insights into the coal-associated methane architect: the ancient archaebacteria.

Archives of microbiology, 206(5):234.

Exploration and marketable exploitation of coalbed methane (CBM) as cleaner fuel has been started globally. In addition, incidence of methane in coal basins is an imperative fraction of global carbon cycle. Significantly, subsurface coal ecosystem contains methane forming archaea. There is a rising attention in optimizing microbial coal gasification to exploit the abundant or inexpensive coal reserves worldwide. Therefore, it is essential to understand the coalbeds in geo-microbial perspective. Current review provides an in-depth analysis of recent advances in our understanding of how methanoarchaea are distributed in coal deposits globally. Specially, we highlight the findings on coal-associated methanoarchaeal existence, abundance, diversity, metabolic activity, and biogeography in diverse coal basins worldwide. Growing evidences indicates that we have arrived an exciting era of archaeal research. Moreover, gasification of coal into methane by utilizing microbial methanogenesis is a considerable way to mitigate the energy crisis for the rising world population.

RevDate: 2024-04-25

Li Q, Cheng X, Liu X, et al (2024)

Ammonia-oxidizing archaea adapted better to the dark, alkaline oligotrophic karst cave than their bacterial counterparts.

Frontiers in microbiology, 15:1377721.

Subsurface karst caves provide unique opportunities to study the deep biosphere, shedding light on microbial contribution to elemental cycling. Although ammonia oxidation driven by both ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) is well explored in soil and marine environments, our understanding in the subsurface biosphere still remained limited to date. To address this gap, weathered rock and sediment samples were collected from the Xincuntun Cave in Guilin City, an alkaline karst cave, and subjected to high-throughput sequencing and quantification of bacterial and archaeal amoA, along with determination of the potential nitrification rates (PNR). Results revealed that AOA dominated in ammonia oxidation, contributing 48-100% to the PNR, and AOA amoA gene copies outnumbered AOB by 2 to 6 orders. Nitrososphaera dominated in AOA communities, while Nitrosopira dominated AOB communities. AOA demonstrated significantly larger niche breadth than AOB. The development of AOA communities was influenced by deterministic processes (50.71%), while AOB communities were predominantly influenced by stochastic processes. TOC, NH4[+], and Cl[-] played crucial roles in shaping the compositions of ammonia oxidizers at the OTU level. Cross-domain co-occurrence networks highlighted the dominance of AOA nodes in the networks and positive associations between AOA and AOB, especially in the inner zone, suggesting collaborative effort to thrive in extreme environments. Their high gene copies, dominance in the interaction with ammonia oxidizing bacteria, expansive niche breadth and substantial contribution to PNR collectively confirmed that AOA better adapted to alkaline, oligotrophic karst caves environments, and thus play a fundamental role in nitrogen cycling in subsurface biosphere.

RevDate: 2024-04-25

van Wolferen M, Ithurbide S, Santiago-Martínez MG, et al (2024)

Editorial: Molecular Biology of Archaea - 2022.

Frontiers in microbiology, 15:1393932.

RevDate: 2024-04-23

Gulati P, Singh A, Patra S, et al (2024)

Restriction modification systems in archaea: A panoramic outlook.

Heliyon, 10(8):e27382.

Restriction modification (RM) systems are one of the ubiquitous yet primitive defense responses employed by bacteria and archaea with the primary role of safeguarding themselves against invading bacteriophages. Protection of the host occurs by the cleavage of the invading foreign DNA via restriction endonucleases with concomitant methylation of host DNA with the aid of a methyltransferase counterpart. RM systems have been extensively studied in bacteria, however, in the case of archaea there are limited reports of RM enzymes that are investigated to date owing to their inhospitable growth demands. This review aims to broaden the knowledge about what is known about the diversity of RM systems in archaea and encapsulate the current knowledge on restriction and modification enzymes characterized in archaea so far and the role of RM systems in the milieu of archaeal biology.

RevDate: 2024-04-19

Wang Q, Zheng G, Ni L, et al (2024)

Colonization characteristics and dynamic transition of archaea communities on polyethylene and polypropylene microplastics in the sediments of mangrove ecosystems.

Journal of hazardous materials, 471:134343 pii:S0304-3894(24)00922-1 [Epub ahead of print].

Microplastics are a growing concern in mangrove ecosystems; however, their effects on archaeal communities and related ecological processes remain unclear. We conducted in situ biofilm-enrichment experiments to investigate the ecological influence of polyethylene (PE) and polypropylene microplastics on archaeal communities in the sediments of mangrove ecosystems. The archaeal community present on microplastics was distinct from that of the surrounding sediments at an early stage but became increasingly similar over time. Bathyarchaeota, Thaumarchaeota, Euryarchaeota, and Asgardaeota were the most abundant phyla. Methanolobus, an archaeal biomarker, was enriched in PE biofilms, and significantly controlled by homogeneous selection in the plastisphere, indicating an increased potential risk of methane emission. The dominant archaeal assembly process in the sediments was deterministic (58.85%-70.47%), while that of the PE biofilm changed from stochastic to deterministic during the experiment. The network of PE plastispheres showed less complexity and competitive links, and higher modularity and stability than that of sediments. Functional prediction showed an increase in aerobic ammonia oxidation during the experiment, whereas methanogenesis and chemoheterotrophy were significantly higher in the plastisphere. This study provides novel insights into the impact of microplastic pollution on archaeal communities and their mediating ecological functions in mangrove ecosystems.

RevDate: 2024-04-11
CmpDate: 2024-04-11

Price MN, AP Arkin (2024)

A fast comparative genome browser for diverse bacteria and archaea.

PloS one, 19(4):e0301871.

Genome sequencing has revealed an incredible diversity of bacteria and archaea, but there are no fast and convenient tools for browsing across these genomes. It is cumbersome to view the prevalence of homologs for a protein of interest, or the gene neighborhoods of those homologs, across the diversity of the prokaryotes. We developed a web-based tool, fast.genomics, that uses two strategies to support fast browsing across the diversity of prokaryotes. First, the database of genomes is split up. The main database contains one representative from each of the 6,377 genera that have a high-quality genome, and additional databases for each taxonomic order contain up to 10 representatives of each species. Second, homologs of proteins of interest are identified quickly by using accelerated searches, usually in a few seconds. Once homologs are identified, fast.genomics can quickly show their prevalence across taxa, view their neighboring genes, or compare the prevalence of two different proteins. Fast.genomics is available at

RevDate: 2024-04-09

Michimori Y, Izaki R, Su Y, et al (2024)

Removal of phosphoglycolate in hyperthermophilic archaea.

Proceedings of the National Academy of Sciences of the United States of America, 121(16):e2311390121.

Many organisms that utilize the Calvin-Benson-Bassham (CBB) cycle for autotrophic growth harbor metabolic pathways to remove and/or salvage 2-phosphoglycolate, the product of the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). It has been presumed that the occurrence of 2-phosphoglycolate salvage is linked to the CBB cycle, and in particular, the C2 pathway to the CBB cycle and oxygenic photosynthesis. Here, we examined 2-phosphoglycolate salvage in the hyperthermophilic archaeon Thermococcus kodakarensis, an obligate anaerobe that harbors a Rubisco that functions in the pentose bisphosphate pathway. T. kodakarensis harbors enzymes that have the potential to convert 2-phosphoglycolate to glycine and serine, and their genes were identified by biochemical and/or genetic analyses. 2-phosphoglycolate phosphatase activity increased 1.6-fold when cells were grown under microaerobic conditions compared to anaerobic conditions. Among two candidates, TK1734 encoded a phosphatase specific for 2-phosphoglycolate, and the enzyme was responsible for 80% of the 2-phosphoglycolate phosphatase activity in T. kodakarensis cells. The TK1734 disruption strain displayed growth impairment under microaerobic conditions, which was relieved upon addition of sodium sulfide. In addition, glycolate was detected in the medium when T. kodakarensis was grown under microaerobic conditions. The results suggest that T. kodakarensis removes 2-phosphoglycolate via a phosphatase reaction followed by secretion of glycolate to the medium. As the Rubisco in T. kodakarensis functions in the pentose bisphosphate pathway and not in the CBB cycle, mechanisms to remove 2-phosphoglycolate in this archaeon emerged independent of the CBB cycle.

RevDate: 2024-04-09

Gao X, Wang S, Kong W, et al (2024)

Floristic changes and environmental drivers of soil fungi and archaea in different salt-tolerant plant communities in the intertidal habitat of coastal wetlands.

Environmental geochemistry and health, 46(5):167.

Microorganisms are crucial elements of terrestrial ecosystems, which play significant roles in improving soil physicochemical properties, providing plant growth nutrients, degrading toxic and harmful chemicals, and biogeochemical cycling. Variations in the types and quantities of root exudates among different plants greatly alter soil physicochemical properties and result in variations in the diversity, structure, and function of soil microorganisms. Not much is understood about the differences of soil fungi and archaea communities for different plant communities in coastal wetlands, and their response mechanisms to environmental changes. In this study, fungal and archaea communities in soils of Suaeda salsa, Phragmites australis, and Spartina alterniflora in the intertidal habitat of coastal wetlands were selected for research. Soil fungi and archaea were analyzed for diversity, community structure, and function using high throughput ITS and 16S rRNA gene sequencing. The study revealed significant differences in fungi and archaea's diversity and community structure in the rhizosphere soil of three plant communities. At the same time, there is no significant difference in the functional groups. SOM, TP, AP, MC, EC and SOM, TN, TP, AP, MC, EC are the primary environmental determinants affecting changes in soil fungal and archaeal communities, respectively. Variations in the diversity, community structure, and ecological functions of fungi and archaea can be used as indicators characterizing the impact of external disturbances on the soil environment, providing a theoretical foundation for the effective utilization of soil microbial resources, thereby achieving the goal of environmental protection and health promotion.

RevDate: 2024-04-06
CmpDate: 2024-04-05

Yin X, Zhou G, Cai M, et al (2024)

Physiological versatility of ANME-1 and Bathyarchaeotoa-8 archaea evidenced by inverse stable isotope labeling.

Microbiome, 12(1):68.

BACKGROUND: The trophic strategy is one key principle to categorize microbial lifestyles, by broadly classifying microorganisms based on the combination of their preferred carbon sources, electron sources, and electron sinks. Recently, a novel trophic strategy, i.e., chemoorganoautotrophy-the utilization of organic carbon as energy source but inorganic carbon as sole carbon source-has been specifically proposed for anaerobic methane oxidizing archaea (ANME-1) and Bathyarchaeota subgroup 8 (Bathy-8).

RESULTS: To further explore chemoorganoautotrophy, we employed stable isotope probing (SIP) of nucleic acids (rRNA or DNA) using unlabeled organic carbon and [13]C-labeled dissolved inorganic carbon (DIC), i.e., inverse stable isotope labeling, in combination with metagenomics. We found that ANME-1 archaea actively incorporated [13]C-DIC into RNA in the presence of methane and lepidocrocite when sulfate was absent, but assimilated organic carbon when cellulose was added to incubations without methane additions. Bathy-8 archaea assimilated [13]C-DIC when lignin was amended; however, their DNA was derived from both inorganic and organic carbon sources rather than from inorganic carbon alone. Based on SIP results and supported by metagenomics, carbon transfer between catabolic and anabolic branches of metabolism is possible in these archaeal groups, indicating their anabolic versatility.

CONCLUSION: We provide evidence for the incorporation of the mixed organic and inorganic carbon by ANME-1 and Bathy-8 archaea in the environment. Video Abstract.

RevDate: 2024-03-30
CmpDate: 2024-03-28

Fry M (2024)

The discovery of archaea: from observed anomaly to consequential restructuring of the phylogenetic tree.

History and philosophy of the life sciences, 46(2):16.

Observational and experimental discoveries of new factual entities such as objects, systems, or processes, are major contributors to some advances in the life sciences. Yet, whereas discovery of theories was extensively deliberated by philosophers of science, very little philosophical attention was paid to the discovery of factual entities. This paper examines historical and philosophical aspects of the experimental discovery by Carl Woese of archaea, prokaryotes that comprise one of the three principal domains of the phylogenetic tree. Borrowing Kuhn's terminology, this discovery of a major biological entity was made during a 'normal science' project of building molecular taxonomy for prokaryotes. Unexpectedly, however, an observed anomaly instigated the discovery of archaea. Substantiation of the existence of the new archaeal entity and consequent reconstruction of the phylogenetic tree prompted replacement of a long-held model of a prokarya and eukarya bipartite tree of life by a new model of a tripartite tree comprising of bacteria, archaea, and eukarya. This paper explores the history and philosophical implications of the progression of Woese's project from normal science to anomaly-instigated model-changing discovery. It is also shown that the consequential discoveries of RNA splicing and of ribozymes were similarly prompted by unexpected irregularities during normal science activities. It is thus submitted that some discoveries of factual biological entities are triggered by unforeseen observational or experimental anomalies.

RevDate: 2024-03-23

Baker BA, Gutiérrez-Preciado A, Rodríguez Del Río Á, et al (2024)

Expanded phylogeny of extremely halophilic archaea shows multiple independent adaptations to hypersaline environments.

Nature microbiology [Epub ahead of print].

Extremely halophilic archaea (Haloarchaea, Nanohaloarchaeota, Methanonatronarchaeia and Halarchaeoplasmatales) thrive in saturating salt concentrations where they must maintain osmotic equilibrium with their environment. The evolutionary history of adaptations enabling salt tolerance remains poorly understood, in particular because the phylogeny of several lineages is conflicting. Here we present a resolved phylogeny of extremely halophilic archaea obtained using improved taxon sampling and state-of-the-art phylogenetic approaches designed to cope with the strong compositional biases of their proteomes. We describe two uncultured lineages, Afararchaeaceae and Asbonarchaeaceae, which break the long branches at the base of Haloarchaea and Nanohaloarchaeota, respectively. We obtained 13 metagenome-assembled genomes (MAGs) of these archaea from metagenomes of hypersaline aquatic systems of the Danakil Depression (Ethiopia). Our phylogenomic analyses including these taxa show that at least four independent adaptations to extreme halophily occurred during archaeal evolution. Gene-tree/species-tree reconciliation suggests that gene duplication and horizontal gene transfer played an important role in this process, for example, by spreading key genes (such as those encoding potassium transporters) across extremely halophilic lineages.

RevDate: 2024-03-20

Batista M, Langendijk-Genevaux P, Kwapisz M, et al (2024)

Evolutionary and functional insights into the Ski2-like helicase family in Archaea: a comparison of Thermococcales ASH-Ski2 and Hel308 activities.

NAR genomics and bioinformatics, 6(1):lqae026.

RNA helicases perform essential housekeeping and regulatory functions in all domains of life by binding and unwinding RNA molecules. The Ski2-like proteins are primordial helicases that play an active role in eukaryotic RNA homeostasis pathways, with multiple homologs having specialized functions. The significance of the expansion and diversity of Ski2-like proteins in Archaea, the third domain of life, has not yet been established. Here, by studying the phylogenetic diversity of Ski2-like helicases among archaeal genomes and the enzymatic activities of those in Thermococcales, we provide further evidence of the function of this protein family in archaeal metabolism of nucleic acids. We show that, in the course of evolution, ASH-Ski2 and Hel308-Ski2, the two main groups of Ski2-like proteins, have diverged in their biological functions. Whereas Hel308 has been shown to mainly act on DNA, we show that ASH-Ski2, previously described to be associated with the 5'-3' aRNase J exonuclease, acts on RNA by supporting an efficient annealing activity, but also an RNA unwinding with a 3'-5' polarity. To gain insights into the function of Ski2, we also analyse the transcriptome of Thermococcus barophilus ΔASH-Ski2 mutant strain and provide evidence of the importance of ASH-Ski2 in cellular metabolism pathways related to translation.

RevDate: 2024-03-18

Guo K, Li D, Hao T, et al (2024)

Potential directions for future development of mainstream partial nitrification-anammox processes: Ammonia-oxidizing archaea as novel functional microorganisms providing nitrite.

Bioresource technology pii:S0960-8524(24)00308-0 [Epub ahead of print].

The application of ammonia-oxidizing archaea (AOA)-based partial nitrification-anammox (PN-A) for mainstream wastewater treatment has attracted research interest because AOA can maintain higher activity in low-temperature environments and they have higher affinity for oxygen and ammonia-nitrogen compared with ammonia-oxidizing bacteria (AOB), thus facilitating stabilized nitrite production, deep removal of low-ammonia, and nitrite-oxidizing bacteria suppression. Moreover, the low affinity of AOA for ammonia makes them more tolerant to N-shock loading and more efficiently integrated with anaerobic ammonium oxidation (anammox). Based on the limitations of the AOB-based PN-A process, this review comprehensively summarizes the potential and significance of AOA for nitrite supply, then gives strategies and influencing factors for replacing AOB with AOA. Additionally, the methods and key influences on the coupling of AOA and anammox are explored. Finally, this review proposes four AOA-based oxygen- or ammonia-limited autotrophic nitritation/denitrification processes to address the low effluent quality and instability of mainstream PN-A processes.

RevDate: 2024-03-18
CmpDate: 2024-03-18

Alghamrawy BT, Hegazy GE, Sabry SA, et al (2024)

Production, characterization and biomedical potential of biosurfactants produced by haloalkaliphilic archaea from Wadi El-Natrun, Egypt.

Microbial cell factories, 23(1):84.

Extreme halophilic archaea that can live in high saline environments can offer potential applications in different biotechnological fields. This study delves into the fascinating field of halophilic archaea and their ability to produce biosurfactants. Some strains of haloarchaea were isolated from Wadi El-Natrun and were screened for biosurfactants production in a standard basal medium using emulsification index assay. Two strains were chosen as the potential strains for surface tension reduction. They were identified as Natrialba sp. BG1 and N3. The biosurfactants production was optimized and the produced emulsifiers were partially purified and identified using FTIR and NMR. Sequential statistical optimization, Plackett-Burman (PB) and Box-Behnken Designs (BBD) were carried out using 5 factors: oil, NaCl, casamino acids, pH, and inoculum size. The most significant factors were used for the next Response Surface Methodology experiment. The final optimal conditions for biosurfactants production were the inoculum size 2% pH 11 and NaCl 250 g/L, for Natrialba sp. BG1 and inoculum size 2.2%, pH 10 and NaCl 100 g/L for Natrialba sp. N3. The produced biosurfactants were tested for wound healing and the results indicated that Natrialba sp. BG1 biosurfactants is more efficient than Natrialba sp. N3 biosurfactants. Biosurfactants extracts were tested for their cytotoxic effects on normal cell line as well as on different cancer cells using MTT assay. The findings demonstrated that varying concentrations of the biosurfactants (31.25, 62.5, 125, 250, 500 and 1000 µg/mL) exhibited cytotoxic effects on the cell lines being tested. Additionally, the outcomes unveiled the presence of anti-inflammatory and antioxidant properties for both biosurfactants. Consequently, they could potentially serve as natural, safe, and efficient novel agents for combating cancer, promoting wound healing, and providing anti-inflammatory and antioxidant benefits.

RevDate: 2024-03-13

Liu X, Sun D, Huang H, et al (2024)

Rice-fish coculture improves paddy soil nitrogen availability in subtropical regions of South China by regulating ammonia-oxidizing bacteria and archaea without phosphorus addition.

The Science of the total environment pii:S0048-9697(24)01784-4 [Epub ahead of print].

Rice-fish coculture (RFC), as a traditional agricultural strategy in China, can optimally utilize the scarce resource, especially in subtropical regions with phosphorus (P) deficiency limiting agricultural production. However, ammonia-oxidizing archaea (AOA) and bacteria (AOB) are responsible for ammonia oxidation, but it remains uncertain whether their community compositions are related to the RFC combined with and without P addition to improve soil nitrogen (N) use efficiency. Here, a microcosm experiment was conducted to assess the impacts of the inorganic P (0 and 50 mg P kg[-1] as KH2PO4) addition combined without and with fish on AOA and AOB community diversities, enzyme activities and N availability. The results showed that RFC significantly increased available N content and urease activity without P addition compared with P addition. RFC significantly increased urease activity and shannon diversity of AOA, and reduced NAG activity and shannon diversity of AOB without P addition, respectively. Higher diversity of AOA compared with that of AOB causes greater competition for resources and energy within their habitats, thereby resulting in lower network complexity. Our findings indicated that the abundances of AOA and AOB are influenced by the introduction of fish and/or P availability, of which AOB is linked to N availability and indirectly influenced by the regulation of N-related enzymes. Overall, RFC could improve paddy soil N availability in subtropical region without P addition, which provides a scientific basis for promoting the practices that RFC reduce N fertilizer application in South China.

RevDate: 2024-03-13

von Hoyningen-Huene AJE, Bang C, Rausch P, et al (2024)

The archaeome in metaorganism research, with a focus on marine models and their bacteria-archaea interactions.

Frontiers in microbiology, 15:1347422.

Metaorganism research contributes substantially to our understanding of the interaction between microbes and their hosts, as well as their co-evolution. Most research is currently focused on the bacterial community, while archaea often remain at the sidelines of metaorganism-related research. Here, we describe the archaeome of a total of eleven classical and emerging multicellular model organisms across the phylogenetic tree of life. To determine the microbial community composition of each host, we utilized a combination of archaea and bacteria-specific 16S rRNA gene amplicons. Members of the two prokaryotic domains were described regarding their community composition, diversity, and richness in each multicellular host. Moreover, association with specific hosts and possible interaction partners between the bacterial and archaeal communities were determined for the marine models. Our data show that the archaeome in marine hosts predominantly consists of Nitrosopumilaceae and Nanoarchaeota, which represent keystone taxa among the porifera. The presence of an archaeome in the terrestrial hosts varies substantially. With respect to abundant archaeal taxa, they harbor a higher proportion of methanoarchaea over the aquatic environment. We find that the archaeal community is much less diverse than its bacterial counterpart. Archaeal amplicon sequence variants are usually host-specific, suggesting adaptation through co-evolution with the host. While bacterial richness was higher in the aquatic than the terrestrial hosts, a significant difference in diversity and richness between these groups could not be observed in the archaeal dataset. Our data show a large proportion of unclassifiable archaeal taxa, highlighting the need for improved cultivation efforts and expanded databases.

RevDate: 2024-03-13

Hu Y, Ma X, Tan S, et al (2024)

Genome-based classification of genera Halosegnis and Salella, and description of four novel halophilic archaea isolated from a tidal flat.

Antonie van Leeuwenhoek, 117(1):51.

The current species of Halosegnis and Salella within the class Halobacteria are closely related based on phylogenetic, phylogenomic, and comparative genomic analyses. The Halosegnis species showed 99.8-100.0% 16S rRNA and 96.6-99.6% rpoB' gene similarities to the Salella species, respectively. Phylogenetic and phylogenomic analyses showed that Salella cibi CBA1133[T], the sole species of Salella, formed a single tight cluster with Halosegnis longus F12-1[T], then with Halosegnis rubeus F17-44[T]. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and average amino acid identity (AAI) values between Salella cibi CBA1133[T] and Halosegnis longus F12-1[T] were 99.2, 94.2, and 98.6%, respectively, much higher than the thresholds for species demarcation. This genome-based classification revealed that the genus Salella should be merged with Halosegnis, and Salella cibi should be a later heterotypic synonym of Halosegnis longus. Halophilic archaeal strains DT72[T], DT80[T], DT85[T], and DT116[T], isolated from the saline soil of a tidal flat in China, were subjected to polyphasic taxonomic characterization. The phenotypic, chemotaxonomic, phylogenetic, and phylogenomic features indicated that strains DT72[T] (= CGMCC 1.18925[T] = JCM 35418[T]), DT80[T] (= CGMCC 1.18926[T] = JCM 35419[T]), DT85[T] (= CGMCC 1.19049[T] = JCM 35605[T]), and DT116[T] (= CGMCC 1.19045[T] = JCM 35606[T]) represent four novel species of the genera Halorussus, Halosegnis and Haloglomus, respectively, for which the names, Halorussus caseinilyticus sp. nov., Halorussus lipolyticus sp. nov., Halosegnis marinus sp. nov., and Haloglomus litoreum sp. nov., are proposed.

RevDate: 2024-03-13

Tran LT, Akıl C, Senju Y, et al (2024)

The eukaryotic-like characteristics of small GTPase, roadblock and TRAPPC3 proteins from Asgard archaea.

Communications biology, 7(1):273.

Membrane-enclosed organelles are defining features of eukaryotes in distinguishing these organisms from prokaryotes. Specification of distinct membranes is critical to assemble and maintain discrete compartments. Small GTPases and their regulators are the signaling molecules that drive membrane-modifying machineries to the desired location. These signaling molecules include Rab and Rag GTPases, roadblock and longin domain proteins, and TRAPPC3-like proteins. Here, we take a structural approach to assess the relatedness of these eukaryotic-like proteins in Asgard archaea, the closest known prokaryotic relatives to eukaryotes. We find that the Asgard archaea GTPase core domains closely resemble eukaryotic Rabs and Rags. Asgard archaea roadblock, longin and TRAPPC3 domain-containing proteins form dimers similar to those found in the eukaryotic TRAPP and Ragulator complexes. We conclude that the emergence of these protein architectures predated eukaryogenesis, however further adaptations occurred in proto-eukaryotes to allow these proteins to regulate distinct internal membranes.

RevDate: 2024-03-12

Chisholm C, Di H, Cameron K, et al (2024)

Contrasting response of comammox Nitrospira, ammonia oxidising bacteria, and archaea to soil pH and nitrogen inputs.

The Science of the total environment pii:S0048-9697(24)01769-8 [Epub ahead of print].

This study aimed to investigate the effect of soil pH change, and nitrogen amendment on ammonia oxidiser abundance and comammox Nitrospira community composition. The experimental design used soil mesocosms placed in a temperature-controlled incubator for 90 days. A Templeton silt loam was used as its physiochemical properties are typical of the region's dairy farms. The results showed that comammox Nitrospira clade B preferred the natural (pH 6.1-6.2) soil pH with no applied nitrogen. Furthermore, synthetic urine (N700) decreased the abundance of comammox Nitrospira clade B. This may have been because the large amounts of available ammonia in the N700 treatments inhibited the growth of comammox Nitrospira. These results suggest that while comammox Nitrospira clade B are present in New Zealand dairy farm soils, but their role in nitrification in the very high nitrogen environment under a urine patch in grazed pastures may be limited. Further research is needed to confirm this. In contrast to comammox, the AOB community (dominated by Nitrosospira) responded positively to the application of synthetic urine. The response was greatest in the high pH soil (7.1), followed by the natural and then the low pH (4.9) soils. This may be due to the difference in ammonia availability. At high pH, the ammonia/ammonium equilibrium favours ammonia production. Calculated ammonia availability in the N700 treatments accurately predicted the AOB amoA gene abundance. Interestingly, the AOA community abundance (which was predominantly made up of Thaumarchaeota group I.1b clade E) seemed to prefer the natural and high pH soils over the low pH. This may be due to the specific lineage of AOA present. AOA did not respond to the application of nitrogen.

RevDate: 2024-03-11

Huda N, Rana MR, Huq MA, et al (2024)

Understanding vermicompost and organic manure interactions: impact on toxic elements, nitrification activity, comammox Nitrospira inopinata, and archaea/bacteria.

Environmental monitoring and assessment, 196(4):355.

Vermicompost is a substantial source of nutrients, promotes soil fertility, and maintains or increases soil organic matter levels. Potentially toxic elements (PTEs) in vermicompost impact on nitrification activity. However, it is yet unknown how vermicompost affects nitrifying bacteria and archaea, comammox Nitrospira inopinata (complete ammonia oxidizers), net nitrification rates (NNRs), and PTEs. The effects of vermicompost application on NNRs, potential nitrification rates (NPs), PTEs, and the abundances of comammox N. inopinata bacteria, nitrite-oxidizing bacteria (NOB), and ammonia-oxidizing bacteria (AOB)/archaea (AOA) were studied. NNRs and NPs were significantly higher (p < 0.05) in fresh cow-dung vermicompost (stored for 40 days) as compared with other organic manure. The level of PTEs (Cu[2+], Fe[2+], Pb[2+], Cd[2+], and Zn[2+]) was significantly lower (p < 0.05) in vermicompost as compared with compost of waste material with Trichoderma and cow dung. Comammox N. inopinata, NOB, AOB, and AOA were significantly higher (p < 0.05) in stored cow-dung vermicompost (more than 1 year) as compared with other organic manure. The results of the scatterplot matrix analysis suggested that Fe[2+], total nitrogen (TN), soil organic carbon (SOC), and total carbon (TC) were linearly correlated (p < 0.001) with NNRs and NPs in vermicompost and organic manure. Similarly, comammox N. inopinata bacteria, NOB, AOB, and AOA were linearly correlated (p < 0.001) with NNR and NP. These results indicated that vermicompost promoted nitrification activity by increasing microbial diversity and abundance, supplying nutrients and organic matter for microbial growth, and facilitating complex microbial interactions. It may be concluded that the influence of vermicompost, which played a great role in PTE concentration reduction, increased chemical, and biological properties, increased the growth rate of nitrifying bacteria/archaea and the nitrogen cycle.

RevDate: 2024-03-10

Peng L, Jia M, Li S, et al (2024)

Developing antibiotics-based strategies to efficiently enrich ammonia-oxidizing archaea from wastewater treatment plants.

The Science of the total environment, 923:171479 pii:S0048-9697(24)01620-6 [Epub ahead of print].

The effects of five antibiotics (i.e., ampicillin, streptomycin, carbenicillin, kanamycin and tetracycline) on ammonia-oxidizing archaea (AOA) enrichment from anoxic activated sludge were investigated. The combined use of five antibiotics during 90-day cultivation could selectively inhibit nitrite-oxidizing bacteria (NOB) and ammonia-oxidizing bacteria (AOB) with AOA unaffected, as evidenced by the nitrite accumulation ratio of 100 % and the proportion of AOA in ammonia-oxidizing microbes over 91 %. The alternative use of five antibiotics was the optimal approach to screening for AOA during 348-day cultivation, which inhibited AOB growth at a level equivalent to the combined use of five antibiotics (the AOB-amoA gene decreased by over 99.90 %), further promoted AOA abundance (the much higher AOA-amoA to AOB-amoA gene copy number ratio (1453.30) than that in the groups with the combined use of five antibiotics (192.94)), eliminated bacterial adaptation to antibiotics and reduced antibiotic-resistant bacteria to form Nitrocosmicus-dominant community (42.35 % in abundance).

RevDate: 2024-03-07

Sun D, Rozmoš M, Kotianová M, et al (2024)

Arbuscular mycorrhizal fungi suppress ammonia-oxidizing bacteria but not archaea across agricultural soils.

Heliyon, 10(4):e26485.

Arbuscular mycorrhizal (AM) fungi are supposedly competing with ammonia-oxidizing microorganisms (AO) for soil nitrogen in form of ammonium. Despite a few studies directly addressing AM fungal and AO interactions, mostly in artificial cultivation substrates, it is not yet clear whether AM fungi can effectively suppress AO in field soils containing complex indigenous microbiomes. To fill this knowledge gap, we conducted compartmentalized pot experiments using four pairs of cropland and grassland soils with varying physicochemical properties. To exclude the interference of roots, a fine nylon mesh was used to separate the rhizosphere and mesh bags, with the latter being filled with unsterile field soils. Inoculation of plants with AM fungus Rhizophagus irregularis LPA9 suppressed AO bacteria (AOB) but not archaea (AOA) in the soils, indicating how soil nitrification could be suppressed by AM fungal presence/activity. In addition, in rhizosphere filled with artificial substrate, AM inoculation did suppress both AOB and AOA, implying more complex interactions between roots, AO, and AM fungi. Besides, we also observed that indigenous AM fungi contained in the field soils eventually did colonize the roots of plants behind the root barrier, and that the extent of such colonization was higher if the soil has previously been taken from cropland than from grassland. Despite this, the effect of experimental AM fungal inoculation on suppression of indigenous AOB in the unsterile field soils did not vanish. It seems that studying processes at a finer temporal scale, using larger buffer zones between rhizosphere and mesh bags, and/or detailed characterization of indigenous AM fungal and AO communities would be needed to uncover further details of the biotic interactions between the AM fungi and indigenous soil AO.

RevDate: 2024-03-04

Wang J, Wen X, Fang Z, et al (2024)

Impact of salinity and organic matter on the ammonia-oxidizing archaea and bacteria in treating hypersaline industrial wastewater: amoA gene abundance and ammonia removal contributions.

Environmental science and pollution research international [Epub ahead of print].

Studies published recently proposed that ammonia-oxidizing archaea (AOA) may be beneficial for hypersaline (salinity > 50 g NaCl L[-1]) industrial wastewater treatment. However, knowledge of AOA activity in hypersaline bioreactors is limited. This study investigated the effects of salinity, organic matter, and practical pickled mustard tuber wastewater (PMTW) on AOA and ammonia-oxidizing bacteria (AOB) in two sequencing batch biofilm reactors (SBBRs). Results showed that despite observed salinity inhibition (p < 0.05), both AOA and AOB contributed to high ammonia removal efficiency at a salinity of 70 g NaCl L[-1] in the two SBBRs. The ammonia removal efficiency of SBBR2 did not significantly differ from that of SBBR1 in the absence of organic matter (p > 0.05). Batch tests and quantitative real-time PCR (qPCR) reveal that salinity and organic matter inhibition resulted in a sharp decline in specific ammonia oxidation rates and amoA gene copy numbers of AOA and AOB (p < 0.05). AOA demonstrated higher abundance and more active ammonia oxidation activity in hypersaline and high organic matter environments. Salinity was positively correlated with the potential ammonia oxidation contribution of AOA (p < 0.05), resulting in a potential transition from AOB dominance to AOA dominance in SBBR1 as salinity levels rose. Moreover, autochthonous AOA in PMTW promoted the abundance and ammonia oxidation activities of AOA in SBBR2, further elevating the nitrification removal efficiency after feeding the practical PMTW. AOA demonstrates greater tolerance to the challenging hypersaline environment, making it a valuable candidate for the treatment of practical industrial wastewater with high salinity and organic content.

RevDate: 2024-03-04

Liu Y, Qian Y, Fu L, et al (2024)

Archaea-Inspired Switchable Nanochannels for On-Demand Lithium Detection by pH Activation.

ACS central science, 10(2):469-476.

With the rapid development of the lithium ion battery industry, emerging lithium (Li) enrichment in nature has attracted ever-growing attention due to the biotoxicity of high Li levels. To date, fast lithium ion (Li[+]) detection remains urgent but is limited by the selectivity, sensitivity, and stability of conventional technologies based on passive response processes. In nature, archaeal plasma membrane ion exchangers (NCLX_Mj) exhibit Li[+]-gated multi/monovalent ion transport behavior, activated by different stimuli. Inspired by NCLX_Mj, we design a pH-controlled biomimetic Li[+]-responsive solid-state nanochannel system for on-demand Li[+] detection using 2-(2-hydroxyphenyl)benzoxazole (HPBO) units as Li[+] recognition groups. Pristine HPBO is not reactive to Li[+], whereas negatively charged HPBO enables specific Li[+] coordination under alkaline conditions to decrease the ion exchange capacity of nanochannels. On-demand Li[+] detection is achieved by monitoring the decline in currents, thereby ensuring precise and stable Li[+] recognition (>0.1 mM) in the toxic range of Li[+] concentration (>1.5 mM) for human beings. This work provides a new approach to constructing Li[+] detection nanodevices and has potential for applications of Li-related industries and medical services.

RevDate: 2024-03-01

Lee KC, Archer SDJ, Kansour MK, et al (2024)

Bioremediation of oily hypersaline soil via autochthonous bioaugmentation with halophilic bacteria and archaea.

The Science of the total environment pii:S0048-9697(24)01418-9 [Epub ahead of print].

Kuwaiti hypersaline soil samples were contaminated with 5 % (w/w) weathered Kuwaiti light crude oil and bioaugmented with autochthonous halophilic hydrocarbonoclastic archaeal and bacterial strains, two each, individually and as consortia. Residual oil contents were determined, and microbial communities were analyzed by culture-dependent and culture-independent approaches initially and seasonally for one year. After one year of the bioremediation process, the mean oil degradation rate was similar across all treated soils including the controlled unbioaugmented one. Oil hydrocarbons were drastically reduced in all soil samples with values ranging from 82.7 % to 93 %. During the bioremediation process, the number of culturable oil-degrading bacteria increased to a range of 142 to 344 CFUx10[4] g[-1] after 12 months of bioaugmentation. Although culture-independent analysis showed a high proportion of inoculants initially, none could be cultured throughout the bioremediation procedure. Within a year, microbial communities changed continually, and 33 species of halotolerant/halophilic hydrocarbonoclastic bacteria were isolated and identified belonged mainly to the three major bacterial phyla Actinobacteria, Proteobacteria, and Firmicutes. The archaeal phylum Halobacterota represented <1 % of the microbial community's relative abundance, which explains why none of its members were cultured. Improving the biodegradability of an already balanced environment by autochthonous bioaugmentation is more involved than just adding the proper oil degraders. This study emphasizes the possibility of a relatively large resistant population, a greater diversity of oil-degrading microorganisms, and the highly selective impacts of oil contamination on hypersaline soil bacterial communities.

RevDate: 2024-02-29

Cena JA, Belmok A, Kyaw CM, et al (2024)

The Archaea domain: Exploring historical and contemporary perspectives with in silico primer coverage analysis for future research in Dentistry.

Archives of oral biology, 161:105936 pii:S0003-9969(24)00057-8 [Epub ahead of print].

OBJECTIVE: The complete picture of how the human microbiome interacts with its host is still largely unknown, particularly concerning microorganisms beyond bacteria. Although existing in very low abundance and not directly linked to causing diseases, archaea have been detected in various sites of the human body, including the gastrointestinal tract, oral cavity, skin, eyes, respiratory and urinary systems. But what exactly are these microorganisms? In the early 1990 s, archaea were classified as a distinct domain of life, sharing a more recent common ancestor with eukaryotes than with bacteria. While archaea's presence and potential significance in Dentistry remain under-recognized, there are concerns that they may contribute to oral dysbiosis. However, detecting archaea in oral samples presents challenges, including difficulties in culturing, the selection of DNA extraction methods, primer design, bioinformatic analysis, and databases.

DESIGN: This is a comprehensive review on the oral archaeome, presenting an in-depth in silico analysis of various primers commonly used for detecting archaea in human body sites.

RESULTS: Among several primer pairs used for detecting archaea in human samples across the literature, only one specifically designed for detecting methanogenic archaea in stool samples, exhibited exceptional coverage levels for the domain and various archaea phyla.

CONCLUSIONS: Our in silico analysis underscores the need for designing new primers targeting not only methanogenic archaea but also nanoarchaeal and thaumarchaeota groups to gain a comprehensive understanding of the archaeal oral community. By doing so, researchers can pave the way for further advancements in the field of oral archaeome research.

RevDate: 2024-02-25

Cisek AA, Szymańska E, Aleksandrzak-Piekarczyk T, et al (2024)

The Role of Methanogenic Archaea in Inflammatory Bowel Disease-A Review.

Journal of personalized medicine, 14(2):.

Methanogenic archaea are a part of the commensal gut microbiota responsible for hydrogen sink and the efficient production of short-chain fatty acids. Dysbiosis of methanogens is suspected to play a role in pathogenesis of variety of diseases, including inflammatory bowel disease (IBD). Unlike bacteria, the diversity of archaea seems to be higher in IBD patients compared to healthy subjects, whereas the prevalence and abundance of gut methanogens declines in IBD, especially in ulcerative colitis. To date, studies focusing on methanogens in pediatric IBD are very limited; nevertheless, the preliminary results provide some evidence that methanogens may be influenced by the chronic inflammatory process in IBD. In this review, we demonstrated the development and diversity of the methanogenic community in IBD, both in adults and children.

RevDate: 2024-02-21

Zhang IH, Borer B, Zhao R, et al (2024)

Uncultivated DPANN archaea are ubiquitous inhabitants of global oxygen-deficient zones with diverse metabolic potential.

mBio [Epub ahead of print].

Archaea belonging to the DPANN (Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota, and Nanohaloarchaeota) superphylum have been found in an expanding number of environments and perform a variety of biogeochemical roles, including contributing to carbon, sulfur, and nitrogen cycling. Generally characterized by ultrasmall cell sizes and reduced genomes, DPANN archaea may form mutualistic, commensal, or parasitic interactions with various archaeal and bacterial hosts, influencing the ecology and functioning of microbial communities. While DPANN archaea reportedly comprise a sizeable fraction of the archaeal community within marine oxygen-deficient zone (ODZ) water columns, little is known about their metabolic capabilities in these ecosystems. We report 33 novel metagenome-assembled genomes (MAGs) belonging to the DPANN phyla Nanoarchaeota, Pacearchaeota, Woesearchaeota, Undinarchaeota, Iainarchaeota, and SpSt-1190 from pelagic ODZs in the Eastern Tropical North Pacific and the Arabian Sea. We find these archaea to be permanent, stable residents of all three major ODZs only within anoxic depths, comprising up to 1% of the total microbial community and up to 25%-50% of archaea as estimated from read mapping to MAGs. ODZ DPANN appear to be capable of diverse metabolic functions, including fermentation, organic carbon scavenging, and the cycling of sulfur, hydrogen, and methane. Within a majority of ODZ DPANN, we identify a gene homologous to nitrous oxide reductase. Modeling analyses indicate the feasibility of a nitrous oxide reduction metabolism for host-attached symbionts, and the small genome sizes and reduced metabolic capabilities of most DPANN MAGs suggest host-associated lifestyles within ODZs.IMPORTANCEArchaea from the DPANN (Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota, and Nanohaloarchaeota) superphylum have diverse metabolic capabilities and participate in multiple biogeochemical cycles. While metagenomics and enrichments have revealed that many DPANN are characterized by ultrasmall genomes, few biosynthetic genes, and episymbiotic lifestyles, much remains unknown about their biology. We report 33 new DPANN metagenome-assembled genomes originating from the three global marine oxygen-deficient zones (ODZs), the first from these regions. We survey DPANN abundance and distribution within the ODZ water column, investigate their biosynthetic capabilities, and report potential roles in the cycling of organic carbon, methane, and nitrogen. We test the hypothesis that nitrous oxide reductases found within several ODZ DPANN genomes may enable ultrasmall episymbionts to serve as nitrous oxide consumers when attached to a host nitrous oxide producer. Our results indicate DPANN archaea as ubiquitous residents within the anoxic core of ODZs with the potential to produce or consume key compounds.

RevDate: 2024-02-20
CmpDate: 2024-02-19

Ouboter HT, Mesman R, Sleutels T, et al (2024)

Mechanisms of extracellular electron transfer in anaerobic methanotrophic archaea.

Nature communications, 15(1):1477.

Anaerobic methanotrophic (ANME) archaea are environmentally important, uncultivated microorganisms that oxidize the potent greenhouse gas methane. During methane oxidation, ANME archaea engage in extracellular electron transfer (EET) with other microbes, metal oxides, and electrodes through unclear mechanisms. Here, we cultivate ANME-2d archaea ('Ca. Methanoperedens') in bioelectrochemical systems and observe strong methane-dependent current (91-93% of total current) associated with high enrichment of 'Ca. Methanoperedens' on the anode (up to 82% of the community), as determined by metagenomics and transmission electron microscopy. Electrochemical and metatranscriptomic analyses suggest that the EET mechanism is similar at various electrode potentials, with the possible involvement of an uncharacterized short-range electron transport protein complex and OmcZ nanowires.

RevDate: 2024-02-17

Baquero DP, Bignon EA, M Krupovic (2024)

Pleomorphic viruses establish stable relationship with marine hyperthermophilic archaea.

The ISME journal pii:7585948 [Epub ahead of print].

Non-lytic viruses with enveloped pleomorphic virions (family Pleolipoviridae) are ubiquitous in hypersaline environments across the globe and are associated with nearly all major lineages of halophilic archaea. However, their existence in other ecosystems remains largely unknown. Here, we show that evolutionarily related viruses also infect hyperthermophilic archaea thriving in deep-sea hydrothermal vents. Archaeoglobus veneficus pleomorphic virus 1 (AvPV1), the first virus described for any member of the class Archaeoglobi, encodes a morphogenetic module typical of pleolipoviruses, including the characteristic VP4-like membrane fusion protein. We show that AvPV1 is a non-lytic virus chronically produced in liquid cultures without substantially affecting the growth dynamics of its host with a stable virus-to-host ratio of ~1. Mining of genomic and metagenomic databases revealed broad distribution of AvPV1-like viruses in geographically remote hydrothermal vents. Comparative genomics, coupled with phylogenetic analysis of VP4-like fusogens revealed deep divergence of pleomorphic viruses infecting halophilic, methanogenic, and hyperthermophilic archaea, signifying niche separation and coevolution of the corresponding virus-host pairs. Hence, we propose a new virus family, "Thalassapleoviridae", for classification of the marine hyperthermophilic virus AvPV1 and its relatives. Collectively, our results provide insights into the diversity and evolution of pleomorphic viruses beyond hypersaline environments.

RevDate: 2024-02-16

Zheng Y, Wang B, Gao P, et al (2024)

Novel order-level lineage of ammonia-oxidizing archaea widespread in marine and terrestrial environments.

The ISME journal, 18(1):.

Ammonia-oxidizing archaea (AOA) are among the most ubiquitous and abundant archaea on Earth, widely distributed in marine, terrestrial, and geothermal ecosystems. However, the genomic diversity, biogeography, and evolutionary process of AOA populations in subsurface environments are vastly understudied compared to those in marine and soil systems. Here, we report a novel AOA order Candidatus (Ca.) Nitrosomirales which forms a sister lineage to the thermophilic Ca. Nitrosocaldales. Metagenomic and 16S rRNA gene-read mapping demonstrates the abundant presence of Nitrosomirales AOA in various groundwater environments and their widespread distribution across a range of geothermal, terrestrial, and marine habitats. Terrestrial Nitrosomirales AOA show the genetic capacity of using formate as a source of reductant and using nitrate as an alternative electron acceptor. Nitrosomirales AOA appear to have acquired key metabolic genes and operons from other mesophilic populations via horizontal gene transfer, including genes encoding urease, nitrite reductase, and V-type ATPase. The additional metabolic versatility conferred by acquired functions may have facilitated their radiation into a variety of subsurface, marine, and soil environments. We also provide evidence that each of the four AOA orders spans both marine and terrestrial habitats, which suggests a more complex evolutionary history for major AOA lineages than previously proposed. Together, these findings establish a robust phylogenomic framework of AOA and provide new insights into the ecology and adaptation of this globally abundant functional guild.

RevDate: 2024-02-15

Lu Z, Zhang S, Liu Y, et al (2024)

Origin of eukaryotic-like Vps23 shapes an ancient functional interplay between ESCRT and ubiquitin system in Asgard archaea.

Cell reports, 43(2):113781 pii:S2211-1247(24)00109-8 [Epub ahead of print].

Functional interplay between the endosomal sorting complexes required for transport (ESCRT) and the ubiquitin system underlies the ubiquitin-dependent cargo-sorting pathway of the eukaryotic endomembrane system, yet its evolutionary origin remains unclear. Here, we show that a UEV-Vps23 protein family, which contains UEV and Vps23 domains, mediates an ancient ESCRT and ubiquitin system interplay in Asgard archaea. The UEV binds ubiquitin with high affinity, making the UEV-Vps23 a sensor for sorting ubiquitinated cargo. A steadiness box in the Vps23 domain undergoes ubiquitination through an Asgard E1, E2, and RING E3 cascade. The UEV-Vps23 switches between autoinhibited and active forms, regulating the ESCRT and ubiquitin system interplay. Furthermore, the shared sequence and structural homology among the UEV-Vps23, eukaryotic Vps23, and archaeal CdvA suggest a common evolutionary origin. Together, this work expands our understanding of the ancient ESCRT and ubiquitin system interplay that likely arose antedating divergent evolution between Asgard archaea and eukaryotes.

RevDate: 2024-02-14

Ju H, Zhang J, Zou Y, et al (2024)

Bacteria undergo significant shifts while archaea maintain stability in Pocillopora damicornis under sustained heat stress.

Environmental research pii:S0013-9351(24)00373-6 [Epub ahead of print].

Global warming reportedly poses a critical risk to coral reef ecosystems. Bacteria and archaea are crucial components of the coral holobiont. The response of archaea associated with warming is less well understood than that of the bacterial community in corals. Also, there have been few studies on the dynamics of the microbial community in the coral holobiont under long-term heat stress. In order to track the dynamic alternations in the microbial communities within the heat-stressed coral holobiont, three-week heat-stress monitoring was carried out on the coral Pocillopora damicornis. The findings demonstrate that the corals were stressed at 32 °C, and showed a gradual decrease in Symbiodiniaceae density with increasing duration of heat stress. The archaeal community in the coral holobiont remained relatively unaltered by the increasing temperature, whereas the bacterial community was considerably altered. Sustained heat stress exacerbated the dissimilarities among parallel samples of the bacterial community, confirming the Anna Karenina Principle in animal microbiomes. Heat stress leads to more complex and unstable microbial networks, characterized by an increased average degree and decreased modularity, respectively. With the extension of heat stress duration, the relative abundances of the gene (nifH) and genus (Tistlia) associated with nitrogen fixation increased in coral samples, as well as the potential pathogenic bacteria (Flavobacteriales) and opportunistic bacteria (Bacteroides). Hence, our findings suggest that coral hosts might recruit nitrogen-fixing bacteria during the initial stages of suffering heat stress. An environment that is conducive to the colonization and development of opportunistic and pathogenic bacteria when the coral host becomes more susceptible as heat stress duration increases.

RevDate: 2024-02-13

Ghimire-Kafle S, Weaver ME, Kimbrel MP, et al (2024)

Competition between ammonia-oxidizing archaea and complete ammonia oxidizers from freshwater environments.

Applied and environmental microbiology [Epub ahead of print].

Aerobic ammonia oxidizers (AOs) are prokaryotic microorganisms that contribute to the global nitrogen cycle by performing the first step of nitrification, the oxidation of ammonium to nitrite and nitrate. While aerobic AOs are found ubiquitously, their distribution is controlled by key environmental conditions such as substrate (ammonium) availability. Ammonia-oxidizing archaea (AOA) and complete ammonia oxidizers (comammox) are generally found in oligotrophic environments with low ammonium availability. However, whether AOA and comammox share these habitats or outcompete each other is not well understood. We assessed the competition for ammonium between an AOA and comammox enriched from the freshwater Lake Burr Oak. The AOA enrichment culture (AOA-BO1) contained Nitrosarchaeum sp. BO1 as the ammonia oxidizer and Nitrospira sp. BO1 as the nitrite oxidizer. The comammox enrichment BO4 (cmx-BO4) contained the comammox strain Nitrospira sp. BO4. The competition experiments were performed either in continuous cultivation with ammonium as a growth-limiting substrate or in batch cultivation with initial ammonium concentrations of 50 and 500 µM. Regardless of the ammonium concentration, Nitrospira sp. BO4 outcompeted Nitrosarchaeum sp. BO1 under all tested conditions. The dominance of Nitrospira sp. BO4 could be explained by the ability of comammox to generate more energy through the complete oxidation of ammonia to nitrate and their more efficient carbon fixation pathway-the reductive tricarboxylic acid cycle. Our results are supported by the higher abundance of comammox compared to AOA in the sediment of Lake Burr Oak.IMPORTANCENitrification is a key process in the global nitrogen cycle. Aerobic ammonia oxidizers play a central role in the nitrogen cycle by performing the first step of nitrification. Ammonia-oxidizing archaea (AOA) and complete ammonia oxidizers (comammox) are the dominant nitrifiers in environments with low ammonium availability. While AOA have been studied for almost 20 years, comammox were only discovered 8 years ago. Until now, there has been a gap in our understanding of whether AOA and comammox can co-exist or if one strain would be dominant under ammonium-limiting conditions. Here, we present the first study characterizing the competition between freshwater AOA and comammox under varying substrate concentrations. Our results will help in elucidating the niches of two key nitrifiers in freshwater lakes.

RevDate: 2024-02-07

Kuroda K, Nakajima M, Nakai R, et al (2024)

Microscopic and metatranscriptomic analyses revealed unique cross-domain parasitism between phylum Candidatus Patescibacteria/candidate phyla radiation and methanogenic archaea in anaerobic ecosystems.

mBio [Epub ahead of print].

To verify whether members of the phylum Candidatus Patescibacteria parasitize archaea, we applied cultivation, microscopy, metatranscriptomic, and protein structure prediction analyses on the Patescibacteria-enriched cultures derived from a methanogenic bioreactor. Amendment of cultures with exogenous methanogenic archaea, acetate, amino acids, and nucleoside monophosphates increased the relative abundance of Ca. Patescibacteria. The predominant Ca. Patescibacteria were families Ca. Yanofskyibacteriaceae and Ca. Minisyncoccaceae, and the former showed positive linear relationships (r[2] ≥ 0.70) Methanothrix in their relative abundances, suggesting related growth patterns. Methanothrix and Methanospirillum cells with attached Ca. Yanofskyibacteriaceae and Ca. Minisyncoccaceae, respectively, had significantly lower cellular activity than those of the methanogens without Ca. Patescibacteria, as extrapolated from fluorescence in situ hybridization-based fluorescence. We also observed that parasitized methanogens often had cell surface deformations. Some Methanothrix-like filamentous cells were dented where the submicron cells were attached. Ca. Yanofskyibacteriaceae and Ca. Minisyncoccaceae highly expressed extracellular enzymes, and based on structural predictions, some contained peptidoglycan-binding domains with potential involvement in host cell attachment. Collectively, we propose that the interactions of Ca. Yanofskyibacteriaceae and Ca. Minisyncoccaceae with methanogenic archaea are parasitisms.IMPORTANCECulture-independent DNA sequencing approaches have explored diverse yet-to-be-cultured microorganisms and have significantly expanded the tree of life in recent years. One major lineage of the domain Bacteria, Ca. Patescibacteria (also known as candidate phyla radiation), is widely distributed in natural and engineered ecosystems and has been thought to be dependent on host bacteria due to the lack of several biosynthetic pathways and small cell/genome size. Although bacteria-parasitizing or bacteria-preying Ca. Patescibacteria have been described, our recent studies revealed that some lineages can specifically interact with archaea. In this study, we provide strong evidence that the relationship is parasitic, shedding light on overlooked roles of Ca. Patescibacteria in anaerobic habitats.

RevDate: 2024-02-06
CmpDate: 2024-02-06

Tirumalai MR, Sivaraman RV, Kutty LA, et al (2023)

Ribosomal Protein Cluster Organization in Asgard Archaea.

Archaea (Vancouver, B.C.), 2023:5512414.

It has been proposed that the superphylum of Asgard Archaea may represent a historical link between the Archaea and Eukarya. Following the discovery of the Archaea, it was soon appreciated that archaeal ribosomes were more similar to those of Eukarya rather than Bacteria. Coupled with other eukaryotic-like features, it has been suggested that the Asgard Archaea may be directly linked to eukaryotes. However, the genomes of Bacteria and non-Asgard Archaea generally organize ribosome-related genes into clusters that likely function as operons. In contrast, eukaryotes typically do not employ an operon strategy. To gain further insight into conservation of the r-protein genes, the genome order of conserved ribosomal protein (r-protein) coding genes was identified in 17 Asgard genomes (thirteen complete genomes and four genomes with less than 20 contigs) and compared with those found previously in non-Asgard archaeal and bacterial genomes. A universal core of two clusters of 14 and 4 cooccurring r-proteins, respectively, was identified in both the Asgard and non-Asgard Archaea. The equivalent genes in the E. coli version of the cluster are found in the S10 and spc operons. The large cluster of 14 r-protein genes (uS19-uL22-uS3-uL29-uS17 from the S10 operon and uL14-uL24-uL5-uS14-uS8-uL6-uL18-uS5-uL30-uL15 from the spc operon) occurs as a complete set in the genomes of thirteen Asgard genomes (five Lokiarchaeotes, three Heimdallarchaeotes, one Odinarchaeote, and four Thorarchaeotes). Four less conserved clusters with partial bacterial equivalents were found in the Asgard. These were the L30e (str operon in Bacteria) cluster, the L18e (alpha operon in Bacteria) cluster, the S24e-S27ae-rpoE1 cluster, and the L31e, L12..L1 cluster. Finally, a new cluster referred to as L7ae was identified. In many cases, r-protein gene clusters/operons are less conserved in their organization in the Asgard group than in other Archaea. If this is generally true for nonribosomal gene clusters, the results may have implications for the history of genome organization. In particular, there may have been an early transition to or from the operon approach to genome organization. Other nonribosomal cellular features may support different relationships. For this reason, it may be important to consider ribosome features separately.

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

Tang SK, Zhi XY, Zhang Y, et al (2024)

Addendum: Cellular differentiation into hyphae and spores in halophilic archaea.

Nature communications, 15(1):523.

RevDate: 2024-02-01

Scott KM, Payne RR, A Gahramanova (2024)

Widespread dissolved inorganic carbon-modifying toolkits in genomes of autotrophic Bacteria and Archaea and how they are likely to bridge supply from the environment to demand by autotrophic pathways.

Applied and environmental microbiology [Epub ahead of print].

Using dissolved inorganic carbon (DIC) as a major carbon source, as autotrophs do, is complicated by the bedeviling nature of this substance. Autotrophs using the Calvin-Benson-Bassham cycle (CBB) are known to make use of a toolkit comprised of DIC transporters and carbonic anhydrase enzymes (CA) to facilitate DIC fixation. This minireview provides a brief overview of the current understanding of how toolkit function facilitates DIC fixation in Cyanobacteria and some Proteobacteria using the CBB and continues with a survey of the DIC toolkit gene presence in organisms using different versions of the CBB and other autotrophic pathways (reductive citric acid cycle, Wood-Ljungdahl pathway, hydroxypropionate bicycle, hydroxypropionate-hydroxybutyrate cycle, and dicarboxylate-hydroxybutyrate cycle). The potential function of toolkit gene products in these organisms is discussed in terms of CO2 and HCO3[-] supply from the environment and demand by the autotrophic pathway. The presence of DIC toolkit genes in autotrophic organisms beyond those using the CBB suggests the relevance of DIC metabolism to these organisms and provides a basis for better engineering of these organisms for industrial and agricultural purposes.

RevDate: 2024-01-31

Qin W, Wei SP, Zheng Y, et al (2024)

Ammonia-oxidizing bacteria and archaea exhibit differential nitrogen source preferences.

Nature microbiology [Epub ahead of print].

Ammonia-oxidizing microorganisms (AOM) contribute to one of the largest nitrogen fluxes in the global nitrogen budget. Four distinct lineages of AOM: ammonia-oxidizing archaea (AOA), beta- and gamma-proteobacterial ammonia-oxidizing bacteria (β-AOB and γ-AOB) and complete ammonia oxidizers (comammox), are thought to compete for ammonia as their primary nitrogen substrate. In addition, many AOM species can utilize urea as an alternative energy and nitrogen source through hydrolysis to ammonia. How the coordination of ammonia and urea metabolism in AOM influences their ecology remains poorly understood. Here we use stable isotope tracing, kinetics and transcriptomics experiments to show that representatives of the AOM lineages employ distinct regulatory strategies for ammonia or urea utilization, thereby minimizing direct substrate competition. The tested AOA and comammox species preferentially used ammonia over urea, while β-AOB favoured urea utilization, repressed ammonia transport in the presence of urea and showed higher affinity for urea than for ammonia. Characterized γ-AOB co-utilized both substrates. These results reveal contrasting niche adaptation and coexistence patterns among the major AOM lineages.

RevDate: 2024-01-31

Maza-Márquez P, Lee MD, BM Bebout (2024)

Community ecology and functional potential of bacteria, archaea, eukarya and viruses in Guerrero Negro microbial mat.

Scientific reports, 14(1):2561.

In this study, the microbial ecology, potential environmental adaptive mechanisms, and the potential evolutionary interlinking of genes between bacterial, archaeal and viral lineages in Guerrero Negro (GN) microbial mat were investigated using metagenomic sequencing across a vertical transect at millimeter scale. The community composition based on unique genes comprised bacteria (98.01%), archaea (1.81%), eukarya (0.07%) and viruses (0.11%). A gene-focused analysis of bacteria archaea, eukarya and viruses showed a vertical partition of the community. The greatest coverages of genes of bacteria and eukarya were detected in first layers, while the highest coverages of genes of archaea and viruses were found in deeper layers. Many genes potentially related to adaptation to the local environment were detected, such as UV radiation, multidrug resistance, oxidative stress, heavy metals, salinity and desiccation. Those genes were found in bacterial, archaeal and viral lineages with 6477, 44, and 1 genes, respectively. The evolutionary histories of those genes were studied using phylogenetic analysis, showing an interlinking between domains in GN mat.

RevDate: 2024-01-31

Candeliere F, Sola L, Raimondi S, et al (2024)

Good and bad dispositions between archaea and bacteria in the human gut: New insights from metagenomic survey and co-occurrence analysis.

Synthetic and systems biotechnology, 9(1):88-98 pii:S2405-805X(23)00114-X.

Archaea are an understudied component of the human microbiome. In this study, the gut archaeome and bacteriome of 60 healthy adults from different region were analyzed by whole-genome shotgun sequencing. Archaea were ubiquitously found in a wide range of abundances, reaching up to 7.2 %. The dominant archaeal phylum was Methanobacteriota, specifically the family Methanobacteriaceae, encompassing more than 50 % of Archaea in 50 samples. The previously underestimated Thermoplasmatota, mostly composed of Methanomassiliicoccaceae, dominated in 10 subjects (>50 %) and was present in all others except one. Halobacteriota, the sole other archaeal phylum, occurred in negligible concentration, except for two samples (4.6-4.8 %). This finding confirmed that the human gut archaeome is primarily composed of methanogenic organisms and among the known methanogenic pathway: i) hydrogenotrophic reduction of CO2 is the predominant, being the genus Methanobrevibacter and the species Methanobrevibacter smithii the most abundant in the majority of the samples; ii) the second pathway, that involved Methanomassiliicoccales, was the hydrogenotrophic reduction of methyl-compounds; iii) dismutation of acetate or methyl-compounds seemed to be absent. Co-occurrence analysis allowed to unravel correlations between Archaea and Bacteria that shapes the overall structure of the microbial community, allowing to depict a clearer picture of the human gut archaeome.

RevDate: 2024-01-30
CmpDate: 2024-01-29

Rao A, AJM Driessen (2024)

Unraveling the multiplicity of geranylgeranyl reductases in Archaea: potential roles in saturation of terpenoids.

Extremophiles : life under extreme conditions, 28(1):14.

The enzymology of the key steps in the archaeal phospholipid biosynthetic pathway has been elucidated in recent years. In contrast, the complete biosynthetic pathways for proposed membrane regulators consisting of polyterpenes, such as carotenoids, respiratory quinones, and polyprenols remain unknown. Notably, the multiplicity of geranylgeranyl reductases (GGRs) in archaeal genomes has been correlated with the saturation of polyterpenes. Although GGRs, which are responsible for saturation of the isoprene chains of phospholipids, have been identified and studied in detail, there is little information regarding the structure and function of the paralogs. Here, we discuss the diversity of archaeal membrane-associated polyterpenes which is correlated with the genomic loci, structural and sequence-based analyses of GGR paralogs.

RevDate: 2024-01-24

Ni Y, Xu T, Yan S, et al (2024)

Hiding in plain sight: The discovery of complete genomes of 11 hypothetical spindle-shaped viruses that putatively infect mesophilic ammonia-oxidizing archaea.

Environmental microbiology reports [Epub ahead of print].

The genome of a putative Nitrosopumilaceae virus with a hypothetical spindle-shaped particle morphology was identified in the Yangshan Harbour metavirome from the East China Sea through protein similarity comparison and structure analysis. This discovery was accompanied by a set of 10 geographically dispersed close relatives found in the environmental virus datasets from typical locations of ammonia-oxidizing archaeon distribution. Its host prediction was supported by iPHoP prediction and protein sequence similarity. The structure of the predicted major capsid protein, together with the overall N-glycosylation site, the transmembrane helices prediction, the hydrophilicity profile, and the docking simulation of the major capsid proteins, indicate that these viruses resemble spindle-shaped viruses. It suggests a similarly assembled structure and, consequently, a possibly spindle-shaped morphology of these newly discovered archaeal viruses.

RevDate: 2024-01-23

Anonymous (2024)

Correction to 'Rare ribosomal RNA sequences from archaea stabilize the bacterial ribosome'.

RevDate: 2024-01-23

Beeckman F, Drozdzecki A, De Knijf A, et al (2023)

High-throughput assays to identify archaea-targeting nitrification inhibitors.

Frontiers in plant science, 14:1283047.

Nitrification is a microbial process that converts ammonia (NH3) to nitrite (NO2 [-]) and then to nitrate (NO3 [-]). The first and rate-limiting step in nitrification is ammonia oxidation, which is conducted by both bacteria and archaea. In agriculture, it is important to control this process as high nitrification rates result in NO3 [-] leaching, reduced nitrogen (N) availability for the plants and environmental problems such as eutrophication and greenhouse gas emissions. Nitrification inhibitors can be used to block nitrification, and as such reduce N pollution and improve fertilizer use efficiency (FUE) in agriculture. Currently applied inhibitors target the bacteria, and do not block nitrification by ammonia-oxidizing archaea (AOA). While it was long believed that nitrification in agroecosystems was primarily driven by bacteria, recent research has unveiled potential significant contributions from ammonia-oxidizing archaea (AOA), especially when bacterial activity is inhibited. Hence, there is also a need for AOA-targeting nitrification inhibitors. However, to date, almost no AOA-targeting inhibitors are described. Furthermore, AOA are difficult to handle, hindering their use to test or identify possible AOA-targeting nitrification inhibitors. To address the need for AOA-targeting nitrification inhibitors, we developed two miniaturized nitrification inhibition assays using an AOA-enriched nitrifying community or the AOA Nitrosospaera viennensis. These assays enable high-throughput testing of candidate AOA inhibitors. We here present detailed guidelines on the protocols and illustrate their use with some examples. We believe that these assays can contribute to the discovery of future AOA-targeting nitrification inhibitors, which could complement the currently applied inhibitors to increase nitrification inhibition efficiency in the field and as such contribute to a more sustainable agriculture.

RevDate: 2024-01-21

Tang M, Chen Q, Zhong H, et al (2024)

CPR bacteria and DPANN archaea play pivotal roles in response of microbial community to antibiotic stress in groundwater.

Water research, 251:121137 pii:S0043-1354(24)00037-X [Epub ahead of print].

The accumulation of antibiotics in the natural environment can disrupt microbial population dynamics. However, our understanding of how microbial communities adapt to the antibiotic stress in groundwater ecosystems remains limited. By recovering 2675 metagenome-assembled genomes (MAGs) from 66 groundwater samples, we explored the effect of antibiotics on bacterial, archaeal, and fungal communities, and revealed the pivotal microbes and their mechanisms in coping with antibiotic stress. The results indicated that antibiotics had the most significant influence on bacterial and archaeal communities, while the impact on the fungal community was minimal. Analysis of co-occurrence networks between antibiotics and microbes revealed the critical roles of Candidate Phyla Radiation (CPR) bacteria and DPANN archaea, two representative microbial groups in groundwater ecosystem, in coping with antibiotic resistance and enhancing network connectivity and complexity. Further genomic analysis demonstrated that CPR bacteria carried approximately 6 % of the identified antibiotic resistance genes (ARGs), indicating their potential to withstand antibiotics on their own. Meanwhile, the genomes of CPR bacteria and DPANN archaea were found to encode diverse biosynthetic gene clusters (BGCs) responsible for producing antimicrobial metabolites, which could not only assist CPR and DPANN organisms but also benefit the surrounding microbes in combating antibiotic stress. These findings underscore the significant impact of antibiotics on prokaryotic microbial communities in groundwater, and highlight the importance of CPR bacteria and DPANN archaea in enhancing the overall resilience and functionality of the microbial community in the face of antibiotic stress.

RevDate: 2024-01-19

Müller MC, Lemaire ON, Kurth JM, et al (2024)

Differences in regulation mechanisms of glutamine synthetases from methanogenic archaea unveiled by structural investigations.

Communications biology, 7(1):111.

Glutamine synthetases (GS) catalyze the ATP-dependent ammonium assimilation, the initial step of nitrogen acquisition that must be under tight control to fit cellular needs. While their catalytic mechanisms and regulations are well-characterized in bacteria and eukaryotes, only limited knowledge exists in archaea. Here, we solved two archaeal GS structures and unveiled unexpected differences in their regulatory mechanisms. GS from Methanothermococcus thermolithotrophicus is inactive in its resting state and switched on by 2-oxoglutarate, a sensor of cellular nitrogen deficiency. The enzyme activation overlays remarkably well with the reported cellular concentration for 2-oxoglutarate. Its binding to an allosteric pocket reconfigures the active site through long-range conformational changes. The homolog from Methermicoccus shengliensis does not harbor the 2-oxoglutarate binding motif and, consequently, is 2-oxoglutarate insensitive. Instead, it is directly feedback-inhibited through glutamine recognition by the catalytic Asp50'-loop, a mechanism common to bacterial homologs, but absent in M. thermolithotrophicus due to residue substitution. Analyses of residue conservation in archaeal GS suggest that both regulations are widespread and not mutually exclusive. While the effectors and their binding sites are surprisingly different, the molecular mechanisms underlying their mode of action on GS activity operate on the same molecular determinants in the active site.

RevDate: 2024-01-16

Hackley RK, Vreugdenhil-Hayslette A, Darnell CL, et al (2024)

A conserved transcription factor controls gluconeogenesis via distinct targets in hypersaline-adapted archaea with diverse metabolic capabilities.

PLoS genetics, 20(1):e1011115 pii:PGENETICS-D-23-00973 [Epub ahead of print].

Timely regulation of carbon metabolic pathways is essential for cellular processes and to prevent futile cycling of intracellular metabolites. In Halobacterium salinarum, a hypersaline adapted archaeon, a sugar-sensing TrmB family protein controls gluconeogenesis and other biosynthetic pathways. Notably, Hbt. salinarum does not utilize carbohydrates for energy, uncommon among Haloarchaea. We characterized a TrmB-family transcriptional regulator in a saccharolytic generalist, Haloarcula hispanica, to investigate whether the targets and function of TrmB, or its regulon, is conserved in related species with distinct metabolic capabilities. In Har. hispanica, TrmB binds to 15 sites in the genome and induces the expression of genes primarily involved in gluconeogenesis and tryptophan biosynthesis. An important regulatory control point in Hbt. salinarum, activation of ppsA and repression of pykA, is absent in Har. hispanica. Contrary to its role in Hbt. salinarum and saccharolytic hyperthermophiles, TrmB does not act as a global regulator: it does not directly repress the expression of glycolytic enzymes, peripheral pathways such as cofactor biosynthesis, or catabolism of other carbon sources in Har. hispanica. Cumulatively, these findings suggest rewiring of the TrmB regulon alongside metabolic network evolution in Haloarchaea.

RevDate: 2024-01-15

Lu Z, Xia R, Zhang S, et al (2024)

Evolution of optimal growth temperature in Asgard archaea inferred from the temperature dependence of GDP binding to EF-1A.

Nature communications, 15(1):515.

The archaeal ancestor of eukaryotes apparently belonged to the phylum Asgardarchaeota, but the ecology and evolution of Asgard archaea are poorly understood. The optimal GDP-binding temperature of a translation elongation factor (EF-1A or EF-Tu) has been previously shown to correlate with the optimal growth temperature of diverse prokaryotes. Here, we reconstruct ancestral EF-1A sequences and experimentally measure the optimal GDP-binding temperature of EF-1A from ancient and extant Asgard archaea, to infer the evolution of optimal growth temperatures in Asgardarchaeota. Our results suggest that the Asgard ancestor of eukaryotes was a moderate thermophile, with an optimal growth temperature around 53 °C. The origin of eukaryotes appears to coincide with a transition from thermophilic to mesophilic lifestyle during the evolution of Asgard archaea.

RevDate: 2024-01-13
CmpDate: 2024-01-12

Cisek AA, Szymańska E, Wierzbicka-Rucińska A, et al (2024)

Methanogenic Archaea in the Pediatric Inflammatory Bowel Disease in Relation to Disease Type and Activity.

International journal of molecular sciences, 25(1):.

The inflammatory bowel disease (IBD) is associated with gut microbiota dysbiosis; however, studies on methanogens-especially those focused on children-are extremely limited. The aim of this study was to determine the abundance of total methanogenic archaea and their three subgroups: Methanobrevibacter (Mb.) smithii, Methanosphaera (Ms.) stadtmanae, and Methanomassiliicoccales, in the feces of children with both active and inactive Crohn's disease (CD) and ulcerative colitis (UC). The results of a quantitative real-time PCR were cross-referenced with the disease type (CD vs. UC) and activity assessed with the use of Pediatric Crohn's Disease Activity Index (PCDAI) and Pediatric Ulcerative Colitis Activity Index (PUCAI) indices, and fecal calprotectin (FCP) concentration, and compared with controls. There was a significant decrease in the number of total methanogens in CD and UC compared to controls. The prevalence of total methanogens was also lower in UC compared to controls. Furthermore, patients from the inactive UC group were colonized by a lower number of Mb. smithii, and demonstrated the most pronounced positive correlation between the number of Ms. stadtmanae and the FCP concentration. Our results demonstrate that gut methanogens are related to the type and activity of pediatric IBD.

RevDate: 2024-01-11
CmpDate: 2024-01-11

Hu Y, Ma X, Li XX, et al (2024)

Halomicrococcus gelatinilyticus sp. nov. and Halosimplex aquaticum sp. nov., halophilic archaea isolated from saline soil and an inland solar saltern.

International journal of systematic and evolutionary microbiology, 74(1):.

Two extremely halophilic archaeal strains, GSLN9[T] and XZYJT29[T], were isolated from the saline soil in different regions of western China. Both strains GSLN9[T] and XZYJT29[T] have two 16S rRNA genes with similarities of 95.1 and 94.8 %, respectively. Strain GSLN9[T] was mostly related to the genus Halomicrococcus based on 16S rRNA (showing 91.0-96.0 % identities) and rpoB' genes (showing 92.0 % identity). Strain XZYJT29[T] showed 92.1-97.6 % (16S rRNA gene) and 91.4-93.1 % (rpoB' gene) sequence similarities to its relatives in the genus Halosimplex, respectively. The polar lipid profile of strain GSLN9[T] included phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulphate (PGS), sulphated mannosyl glucosyl diether (S-DGD-1) and sulphated galactosyl mannosyl glucosyl diether (S-TGD-1), mostly similar to that of Halomicrococcus hydrotolerans H22[T]. PA, PG, PGP-Me, S-DGD-1 (S-DGD-PA), S2-DGD, S-TGD-1 and an unidentified glycolipid were detected in strain XZYJT29[T]; this polar lipid composition is similar to those of members of the genus Halosimplex. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between these two strains and their relatives of the genera Halomicrococcus and Halosimplex were no more than 82, 27 and 80 %, respectively, much lower than the thresholds for species demarcation. Other phenotypic characterization results indicated that strains GSLN9[T] and XZYJT29[T] can be differentiated from the current species of the genera Halomicrococcus and Halosimplex, respectively. These results revealed that strains GSLN9[T] (=CGMCC 1.15215[T]=JCM 30842[T]) and XZYJT29[T] (=CGMCC 1.15828[T]=JCM 31853[T]) represent novel species of Halomicrococcus and Halosimplex, for which the names Halomicrococcus gelatinilyticus sp. nov. and Halosimplex aquaticum sp. nov. are proposed.

RevDate: 2024-01-10
CmpDate: 2024-01-10

Li XX, Tan S, Cheng M, et al (2024)

Halospeciosus flavus gen. nov., sp. nov. and Haladaptatus caseinilyticus sp. nov., halophilic archaea isolated from saline soil of an inland solar saltern and offshore sediment.

International journal of systematic and evolutionary microbiology, 74(1):.

Two novel halophilic archaeal strains (XZGYJ-43[T] and ZJ1[T]) were isolated from Mangkang ancient solar saltern (Tibet, PR China) and Zhujiang river inlet (Guangdong, PR China), respectively. The comparison of the 16S rRNA gene sequences revealed that strain XZGYJ-43[T] is related to the current species of the family Halobacteriaceae (89.2-91.7% similarity) and strain ZJ1[T] showed 94.7-98.3% similarity to the current species of the genus Haladaptatus. Phylogenetic analyses based on 16S rRNA genes, rpoB' genes and genomes indicated that strain XZGYJ-43[T] is separate from the related genera, Halocalculus, Salarchaeum and Halarchaeum of the family Halobacteriaceae, and strain ZJ1[T] tightly clusters with the current species of the genus Haladaptatus. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between strain XZGYJ-43[T] and the current species of the family Halobacteriaceae were 71-75, 20-25 and 59-68 %, and these values between strain ZJ1[T] and the current species of the genus Haladaptatus were 77-81, 27-32 and 76-82 %, respectively, clearly below the thresholds for prokaryotic species demarcation. These two strains could be distinguished from their relatives according to differential phenotypic characteristics. The major polar lipids of strain XZGYJ-43[T] were phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), mannosyl glucosyl diether (DGD-1; DGD-PA) and sulphated mannosyl glucosyl diether (S-DGD-1; S-DGD-PA), and those of strain ZJ1[T] were PA, PG, PGP-Me, DGD-PA, S-DGD-1 (S-DGD-PA) and sulphated galactosyl mannosyl glucosyl diether. Based on phenotypic, phylogenetic and genomic data, strain XZGYJ-43[T] (=CGMCC 1.13890[T]=JCM 33735[T]) represents a novel species of a new genus within the family Halobacteriaceae, and strain ZJ1[T] (=CGMCC 1.18785[T]=JCM 34917[T]) represents a novel species of the genus Haladaptatus, for which the names Halospeciosus flavus gen. nov., sp. nov. and Haladaptatus caseinilyticus sp. nov. are proposed, respectively.

RevDate: 2024-01-08

Makarova KS, Zhang C, Wolf YI, et al (2024)

Computational analysis of genes with lethal knockout phenotype and prediction of essential genes in archaea.

mBio [Epub ahead of print].

Only a relatively small fraction of the genes in any bacterium or archaeon is essential for survival as demonstrated by the lethal effect of their disruption. The identification of essential genes and their functions is crucial for understanding fundamental cell biology. However, many of the genes with a lethal knockout phenotype remain poorly functionally characterized, and furthermore, many genes can exhibit this phenotype not because their products perform essential cellular functions but because their knockout activates the toxicity of other genes. We applied state-of-the-art computational methods to predict the functions of a number of uncharacterized genes with the lethal knockout phenotype in two archaeal species and developed a computational approach to predict genes involved in essential functions. These findings advance the current understanding of key functionalities of archaeal cells.

RevDate: 2024-01-08

Hanišáková N, Vítězová M, Vítěz T, et al (2023)

Microbiological insight into various underground gas storages in Vienna Basin focusing on methanogenic Archaea.

Frontiers in microbiology, 14:1293506.

In recent years, there has been a growing interest in extending the potential of underground gas storage (UGS) facilities to hydrogen and carbon dioxide storage. However, this transition to hydrogen storage raises concerns regarding potential microbial reactions, which could convert hydrogen into methane. It is crucial to gain a comprehensive understanding of the microbial communities within any UGS facilities designated for hydrogen storage. In this study, underground water samples and water samples from surface technologies from 7 different UGS objects located in the Vienna Basin were studied using both molecular biology methods and cultivation methods. Results from 16S rRNA sequencing revealed that the proportion of archaea in the groundwater samples ranged from 20 to 58%, with methanogens being the predominant. Some water samples collected from surface technologies contained up to 87% of methanogens. Various species of methanogens were isolated from individual wells, including Methanobacterium sp., Methanocalculus sp., Methanolobus sp. or Methanosarcina sp. We also examined water samples for the presence of sulfate-reducing bacteria known to be involved in microbially induced corrosion and identified species of the genus Desulfovibrio in the samples. In the second part of our study, we contextualized our data by comparing it to available sequencing data from terrestrial subsurface environments worldwide. This allowed us to discern patterns and correlations between different types of underground samples based on environmental conditions. Our findings reveal presence of methanogens in all analyzed groups of underground samples, which suggests the possibility of unintended microbial hydrogen-to-methane conversion and the associated financial losses. Nevertheless, the prevalence of methanogens in our results also highlights the potential of the UGS environment, which can be effectively leveraged as a bioreactor for the conversion of hydrogen into methane, particularly in the context of Power-to-Methane technology.

RevDate: 2024-01-07

Mao Y, Wu J, Yang R, et al (2024)

Novel database for accA gene revealed a vertical variability pattern of autotrophic carbon fixation potential of ammonia oxidizing archaea in a permeable subterranean estuary.

Marine environmental research, 194:106342 pii:S0141-1136(24)00003-5 [Epub ahead of print].

The autotrophic carbon fixation pathway of ammonia-oxidizing archaea (AOA) was the 3-hydroxypropionate/4-hydroxybutyrate (3-HP/4-HB) cycle, of which the acetyl-CoA carboxylase α-submit (accA) gene is widely recognized as the indicator. To date, there is no reference database or suitable cut-off value for operational taxonomic unit (OTU) clustering to analyze the diversity of AOA based on the accA gene. In this study, a reference database with 489 sequences was constructed, all the accA gene sequences was obtained from the AOA enrichment culture, pure culture and environmental samples. Additionally, the 79% was determined as the cut-off value for OTU clustering by comparing the similarity between the accA gene and the 16S rRNA gene. The developed method was verified by analyzing samples from the subterranean estuary and a vertical variation pattern of autotrophic carbon fixation potential of AOA was revealed. This study provided an effective method to analyze the diversity and autotrophic carbon fixation potential of AOA based on accA gene.

RevDate: 2024-01-05

Zhao H, Wu H, Guseman A, et al (2024)

The role of cryptic ancestral symmetry in histone folding mechanisms across Eukarya and Archaea.

PLoS computational biology, 20(1):e1011721 pii:PCOMPBIOL-D-23-01309 [Epub ahead of print].

Histones compact and store DNA in both Eukarya and Archaea, forming heterodimers in Eukarya and homodimers in Archaea. Despite this, the folding mechanism of histones across species remains unclear. Our study addresses this gap by investigating 11 types of histone and histone-like proteins across humans, Drosophila, and Archaea through multiscale molecular dynamics (MD) simulations, complemented by NMR and circular dichroism experiments. We confirm and elaborate on the widely applied "folding upon binding" mechanism of histone dimeric proteins and report a new alternative conformation, namely, the inverted non-native dimer, which may be a thermodynamically metastable configuration. Protein sequence analysis indicated that the inverted conformation arises from the hidden ancestral head-tail sequence symmetry underlying all histone proteins, which is congruent with the previously proposed histone evolution hypotheses. Finally, to explore the potential formations of homodimers in Eukarya, we utilized MD-based AWSEM and AI-based AlphaFold-Multimer models to predict their structures and conducted extensive all-atom MD simulations to examine their respective structural stabilities. Our results suggest that eukaryotic histones may also form stable homodimers, whereas their disordered tails bring significant structural asymmetry and tip the balance towards the formation of commonly observed heterotypic dimers.

RevDate: 2024-01-05

Medina-Chávez NO, Torres-Cerda A, Chacón JM, et al (2023)

Disentangling a metabolic cross-feeding in a halophilic archaea-bacteria consortium.

Frontiers in microbiology, 14:1276438.

Microbial syntrophy, a cooperative metabolic interaction among prokaryotes, serves a critical role in shaping communities, due to the auxotrophic nature of many microorganisms. Syntrophy played a key role in the evolution of life, including the hypothesized origin of eukaryotes. In a recent exploration of the microbial mats within the exceptional and uniquely extreme Cuatro Cienegas Basin (CCB), a halophilic isolate, designated as AD140, emerged as a standout due to its distinct growth pattern. Subsequent genome sequencing revealed AD140 to be a co-culture of a halophilic archaeon from the Halorubrum genus and a marine halophilic bacterium, Marinococcus luteus, both occupying the same ecological niche. This intriguing coexistence hints at an early-stage symbiotic relationship that thrives on adaptability. By delving into their metabolic interdependence through genomic analysis, this study aims to uncover shared characteristics that enhance their symbiotic association, offering insights into the evolution of halophilic microorganisms and their remarkable adaptations to high-salinity environments.

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

Guerra A (2024)

Human associated Archaea: a neglected microbiome worth investigating.

World journal of microbiology & biotechnology, 40(2):60.

The majority of research in the field of human microbiota has predominantly focused on bacterial and fungal communities. Conversely, the human archaeome has received scant attention and remains poorly studied, despite its potential role in human diseases. Archaea have the capability to colonize various human body sites, including the gastrointestinal tract, skin, vagina, breast milk, colostrum, urinary tract, lungs, nasal and oral cavities. This colonization can occur through vertical transmission, facilitated by the transfer of breast milk or colostrum from mother to child, as well as through the consumption of dairy products, organic produce, salty foods, and fermented items. The involvement of these microorganisms in diseases, such as periodontitis, might be attributed to their production of toxic compounds and the detoxification of growth inhibitors for pathogens. However, the precise mechanisms through which these contributions occur remain incompletely understood, necessitating further studies to assess their impact on human health.

RevDate: 2023-12-25

Hinkle JE, Mara P, Beaudoin DJ, et al (2023)

A PCR-Based Survey of Methane-Cycling Archaea in Methane-Soaked Subsurface Sediments of Guaymas Basin, Gulf of California.

Microorganisms, 11(12):.

The Guaymas Basin in the Gulf of California is characterized by active seafloor spreading, the rapid deposition of organic-rich sediments, steep geothermal gradients, and abundant methane of mixed thermogenic and microbial origin. Subsurface sediment samples from eight drilling sites with distinct geochemical and thermal profiles were selected for DNA extraction and PCR amplification to explore the diversity of methane-cycling archaea in the Guaymas Basin subsurface. We performed PCR amplifications with general (mcrIRD), and ANME-1 specific primers that target the alpha (α) subunit of methyl coenzyme M reductase (mcrA). Diverse ANME-1 lineages associated with anaerobic methane oxidation were detected in seven out of the eight drilling sites, preferentially around the methane-sulfate interface, and in several cases, showed preferences for specific sampling sites. Phylogenetically, most ANME-1 sequences from the Guaymas Basin subsurface were related to marine mud volcanoes, seep sites, and the shallow marine subsurface. The most frequently recovered methanogenic phylotypes were closely affiliated with the hyperthermophilic Methanocaldococcaceae, and found at the hydrothermally influenced Ringvent site. The coolest drilling site, in the northern axial trough of Guaymas Basin, yielded the greatest diversity in methanogen lineages. Our survey indicates the potential for extensive microbial methane cycling within subsurface sediments of Guaymas Basin.

RevDate: 2023-12-23

Wu X, Zhang W, Liu G, et al (2023)

Changes in Diversity and Abundance of Ammonia-Oxidizing Archaea and Bacteria along a Glacier Retreating Chronosequence in the Tianshan Mountains, China.

Microorganisms, 11(12): pii:microorganisms11122871.

Glaciers retreating due to global warming create important new habitats, particularly suitable for studying ecosystem development where nitrogen is a limiting factor. Nitrogen availability mainly results from microbial decomposition and transformation processes, including nitrification. AOA and AOB perform the first and rate-limiting step of nitrification. Investigating the abundance and diversity of AOA and AOB is essential for understanding early ecosystem development. The dynamics of AOA and AOB community structure along a soil chronosequence in Tianshan No. 1 Glacier foreland were analyzed using qPCR and clone library methods. The results consistently showed low quantities of both AOA and AOB throughout the chronosequence. Initially, the copy numbers of AOB were higher than those of AOA, but they decreased in later stages. The AOB community was dominated by "Nitrosospira cluster ME", while the AOA community was dominated by "the soil and sediment 1". Both communities were potentially connected to supra- and subglacial microbial communities during early stages. Correlation analysis revealed a significant positive correlation between the ratios of AOA and AOB with soil ammonium and total nitrogen levels. These results suggest that variations in abundance and diversity of AOA and AOB along the chronosequences were influenced by ammonium availability during glacier retreat.

RevDate: 2023-12-22

Trouche B, Schauberger C, Bouderka F, et al (2023)

Distribution and genomic variation of ammonia-oxidizing archaea in abyssal and hadal surface sediments.

ISME communications, 3(1):133.

Ammonia-oxidizing archaea of the phylum Thaumarchaeota play a central role in the biogeochemical cycling of nitrogen in benthic sediments, at the interface between pelagic and subsurface ecosystems. However, our understanding of their niche separation and of the processes controlling their population structure in hadal and abyssal surface sediments is still limited. Here, we reconstructed 47 AOA metagenome-assembled genomes (MAGs) from surface sediments of the Atacama and Kermadec trench systems. They formed deep-sea-specific groups within the family Nitrosopumilaceae and were assigned to six amoA gene-based clades. MAGs from different clades had distinct distribution patterns along oxygen-ammonium counter gradients in surface sediments. At the species level, MAGs thus seemed to form different ecotypes and follow deterministic niche-based distributions. In contrast, intraspecific population structure, defined by patterns of Single Nucleotide Variants (SNV), seemed to reflect more complex contributions of both deterministic and stochastic processes. Firstly, the bathymetric range had a strong effect on population structure, with distinct populations in abyssal plains and hadal trenches. Then, hadal populations were clearly separated by trench system, suggesting a strong isolation-by-topography effect, whereas abyssal populations were rather controlled by sediment depth or geographic distances, depending on the clade considered. Interestingly, genetic variability between samples was lowest in sediment layers where the mean MAG coverage was highest, highlighting the importance of selective pressure linked with each AOA clade's ecological niche. Overall, our results show that deep-sea AOA genome distributions seem to follow both deterministic and stochastic processes, depending on the genomic variability scale considered.

RevDate: 2023-12-23

Rafiq M, Hassan N, Rehman M, et al (2023)

Challenges and Approaches of Culturing the Unculturable Archaea.

Biology, 12(12):.

Since Carl Woese's discovery of archaea as a third domain of life, numerous archaeal species have been discovered, yet archaeal diversity is poorly characterized. Culturing archaea is complicated, but several queries about archaeal cell biology, evolution, physiology, and diversity need to be solved by culturing and culture-dependent techniques. Increasing interest in demand for innovative culturing methods has led to various technological and methodological advances. The current review explains frequent hurdles hindering uncultured archaea isolation and discusses features for more archaeal cultivation. This review also discusses successful strategies and available media for archaeal culturing, which might be helpful for future culturing practices.

RevDate: 2023-12-16

Xiang Y, Zhou T, Deng S, et al (2023)

Nitrite improved nitrification efficiency and enriched ammonia-oxidizing archaea and bacteria in the simultaneous nitrification and denitrification process.

Water research X, 21:100204.

Simultaneous nitrification and denitrification (SND) is effective and energy-saving for wastewater treatment. As an inevitable intermediate product in the SND process, nitrite affects the efficiency of ammonia oxidation and the composition of nitrifiers. To investigate the impact of nitrite on ammonia oxidation efficiency, two reactors performing SND were respectively operated without nitrite (R1 as control) and with 20 mg N/L nitrite addition (R2 as experimental). The total nitrogen removal efficiency was 74.5% in R1 while 99.0% in R2. With nitrite addition (i.e., 20 mg N/L), the ammonia removal rate in R2 increased to 4.5 times of that in R1. The ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) contributed to respective around 46.9% and 41.8% ammonia removal in R2 based on the results of experiments with specific inhibitors. The number of respective AOA and AOB ammonia monooxygenase gene (amoA) copies increased by 280 and 30 times due to nitrite addition, according to the qPCR results. The high-throughput sequencing results illustrated the increase of dominant AOB species from 0.40% in R1 to 1.59% in R2 and the phylogenetic tree analysis revealed a close link to Nitrosospira multiformis. These results indicated that the ammonia removal efficiency was improved and AOA/AOB were enriched by nitrite addition. The specific nitrite reductases in AOA and AOB boosted the adaptation of nitrite addition. This study demonstrated the positive impacts of nitrite addition on the ammonia removal efficiency and rate in the SND process.

RevDate: 2023-12-11

Boswinkle K, Dinh TA, KD Allen (2023)

Biochemical and genetic studies define the functions of methylthiotransferases in methanogenic and methanotrophic archaea.

Frontiers in microbiology, 14:1304671.

Methylthiotransferases (MTTases) are radical S-adenosylmethionine (SAM) enzymes that catalyze the addition of a methylthio (-SCH3) group to an unreactive carbon center. These enzymes are responsible for the production of 2-methylthioadenosine (ms[2]A) derivatives found at position A37 of select tRNAs in all domains of life. Additionally, some bacteria contain the RimO MTTase that catalyzes the methylthiolation of the S12 ribosomal protein. Although the functions of MTTases in bacteria and eukaryotes have been established via detailed genetic and biochemical studies, MTTases from the archaeal domain of life are understudied and the substrate specificity determinants of MTTases remain unclear. Here, we report the in vitro enzymatic activities of an MTTase (C4B56_06395) from a thermophilic Ca. Methanophagales anaerobic methanotroph (ANME) as well as the MTTase from a hyperthermophilic methanogen - MJ0867 from Methanocaldococcus jannaschii. Both enzymes catalyze the methylthiolation of N[6]-threonylcarbamoyladenosine (t[6]A) and N[6]-hydroxynorvalylcarbamoyladenosine (hn[6]A) residues to produce 2-methylthio-N[6]-threonylcarbamoyladenosine (ms[2]t[6]A) and 2-methylthio-N[6]-hydroxynorvalylcarbamoyladenosine (ms[2]hn[6]A), respectively. To further assess the function of archaeal MTTases, we analyzed select tRNA modifications in a model methanogen - Methanosarcina acetivorans - and generated a deletion of the MTTase-encoding gene (MA1153). We found that M. acetivorans produces ms[2]hn[6]A in exponential phase of growth, but does not produce ms[2]t[6]A in detectable amounts. Upon deletion of MA1153, the ms[2]A modification was absent, thus confirming the function of MtaB-family MTTases in generating ms[2]hn[6]A modified nucleosides in select tRNAs.

RevDate: 2023-12-07

Zhang J, Zhou M, Shi F, et al (2023)

The abundance of comammox bacteria was higher than that of ammonia-oxidizing archaea and bacteria in rhizosphere of emergent macrophytes in a typical shallow lake riparian.

International microbiology : the official journal of the Spanish Society for Microbiology [Epub ahead of print].

Complete ammonia oxidation (comammox) bacteria can complete the whole nitrification process independently, which not only challenges the classical two-step nitrification theory but also updates long-held perspective of microbial ecological relationship in nitrification process. Although comammox bacteria have been found in many ecosystems in recent years, there is still a lack of research on the comammox process in rhizosphere of emergent macrophytes in lakeshore zone. Sediment samples were collected in this study from rhizosphere, far-rhizosphere, and non-rhizosphere of emergent macrophytes along the shore of Lake Liangzi, a shallow lake. The diversity of comammox bacteria and amoA gene abundance of comammox bacteria, ammonia-oxidizing archaea (AOA), and ammonia-oxidizing bacteria (AOB) in these samples were measured. The results showed that comammox bacteria widely existed in the rhizosphere of emergent macrophytes and fell into clade A.1, clade A.2, and clade B, and clade A was the predominant community in all sampling sites. The abundance of comammox amoA gene (6.52 × 10[6]-2.45 × 10[8] copies g[-1] dry sediment) was higher than that of AOB amoA gene (6.58 × 10[4]-3.58 × 10[6] copies g[-1] dry sediment), and four orders of magnitude higher than that of AOA amoA gene (7.24 × 10[2]-6.89 × 10[3] copies g[-1] dry sediment), suggesting that the rhizosphere of emergent macrophytes is more favorable for the growth of comammox bacteria than that of AOB and AOA. Our study indicated that the comammox bacteria may play important roles in ammonia-oxidizing processes in all different rhizosphere regions.

RevDate: 2023-12-04

Qu L, Li M, Gong F, et al (2023)

Oxygen-driven divergence of marine group II archaea reflected by transitions of superoxide dismutases.

Microbiology spectrum [Epub ahead of print].

Reactive oxygen species (ROS), including superoxide anion, is a series of substances that cause oxidative stress for all organisms. Marine group II (MGII) archaea are mainly live in the surface seawater and exposed to considerable ROS. Therefore, it is important to understand the antioxidant capacity of MGII. Our research found that Fe/Mn- superoxide dismutase (Fe/MnSOD) may be more suitable for MGII to resist oxidative damage, and the changes in oxygen concentrations and SOD metallic cofactors play an important role in the selection of SOD by the 17 clades of MGII, which in turn affects the species differentiation of MGII. Overall, this study provides insight into the co-evolutionary history of these uncultivated marine archaea with the earth system.

RevDate: 2023-12-02

Wu Y, Zhou S, Li Y, et al (2023)

Climate and local environment co-mediate the taxonomic and functional diversity of bacteria and archaea in the Qinghai-Tibet Plateau rivers.

The Science of the total environment pii:S0048-9697(23)07597-6 [Epub ahead of print].

Understanding the environmental response patterns of riverine microbiota is essential for predicting the potential impact of future environmental change on river ecosystems. Vulnerable plateau ecosystems are particularly sensitive to climate and local environmental changes, however, the environmental response patterns of the taxonomic and functional diversity of riverine microbiota remain unclear. Here, we conducted a systematic investigation of the taxonomic and functional diversity of bacteria and archaea from riparian soils, sediments, and water across the elevation of 1800- 4800 m in the Qinghai-Tibet Plateau rivers. We found that within the elevation range of 1800 to 3800 m, riparian soils and sediments exhibited similarities and stabilities in microbial taxonomic and functional diversity, and water microbiomes were more sensitive with great fluctuations in microbial diversity. Beyond the elevation of 3800 m, microbial diversity declined across all riverine matrixes. Local environmental conditions can influence the sensitivity of microbiomes to climate change. The combination of critical climate and local environmental factors, including total nitrogen, total organic carbon, as well as climate variables associated with temperature and precipitation, provided better explanations for microbial diversity than single-factor analyses. Under the extremely adverse scenario of high greenhouse gas emission concentrations (SSP585), we anticipate that by the end of this century, the bacterial, archaeal, and microbial functional diversity across the river network of the Yangtze and Yellow source basin would potentially change by -16.9- 5.2 %, -16.1- 5.7 %, and -9.3- 6.4 %, respectively. Overall, climate and local environments jointly shaped the microbial diversity in plateau river ecosystems, and water microbiomes would provide early signs of environmental changes. Our study provides effective theoretical foundations for the conservation of river biodiversity and functional stability under environmental changes.

RevDate: 2023-12-02

Diaz GR, Gaire TN, Ferm P, et al (2023)

Effect of castration timing and weaning strategy on the taxonomic and functional profile of ruminal bacteria and archaea of beef calves.

Animal microbiome, 5(1):61.

BACKGROUND: Beef cattle experience several management challenges across their lifecycle. Castration and weaning, two major interventions in the early life of beef cattle, can have a substantial impact on animal performance. Despite the key role of the rumen microbiome on productive traits of beef cattle, the effect of castration timing and weaning strategy on this microbial community has not been formally described. We assessed the effect of four castration time windows (at birth, turnout, pre-weaning and weaning) and two weaning strategies (fence-line and truck transportation) on the rumen microbiome in a randomized controlled study with 32 male calves across 3 collection days (i.e., time points). Ruminal fluid samples were submitted to shotgun metagenomic sequencing and changes in the taxonomic (microbiota) and functional profile (metagenome) of the rumen microbiome were described.

RESULTS: Using a comprehensive yet stringent taxonomic classification approach, we identified 10,238 unique taxa classified under 40 bacterial and 7 archaeal phyla across all samples. Castration timing had a limited long-term impact on the rumen microbiota and was not associated with changes in alpha and beta diversity. The interaction of collection day and weaning strategy was associated with changes in the rumen microbiota, which experienced a significant decrease in alpha diversity and shifts in beta diversity within 48 h post-weaning, especially in calves abruptly weaned by truck transportation. Calves weaned using a fence-line weaning strategy had lower relative abundance of Bacteroides, Lachnospira, Fibrobacter and Ruminococcus genera compared to calves weaned by truck transportation. Some genes involved in the hydrogenotrophic methanogenesis pathway (fwdB and fwdF) had higher relative abundance in fence-line-weaned calves post-weaning. The antimicrobial resistance gene tetW consistently represented more than 50% of the resistome across time, weaning and castration groups, without significant changes in relative abundance.

CONCLUSIONS: Within the context of this study, castration timing had limited long-term effects on the rumen microbiota, while weaning strategy had short-term effects on the rumen microbiota and methane-associated metagenome, but not on the rumen resistome.

RevDate: 2023-12-02

Protasov E, Nonoh JO, Kästle Silva JM, et al (2023)

Diversity and taxonomic revision of methanogens and other archaea in the intestinal tract of terrestrial arthropods.

Frontiers in microbiology, 14:1281628.

Methane emission by terrestrial invertebrates is restricted to millipedes, termites, cockroaches, and scarab beetles. The arthropod-associated archaea known to date belong to the orders Methanobacteriales, Methanomassiliicoccales, Methanomicrobiales, and Methanosarcinales, and in a few cases also to non-methanogenic Nitrososphaerales and Bathyarchaeales. However, all major host groups are severely undersampled, and the taxonomy of existing lineages is not well developed. Full-length 16S rRNA gene sequences and genomes of arthropod-associated archaea are scarce, reference databases lack resolution, and the names of many taxa are either not validly published or under-classified and require revision. Here, we investigated the diversity of archaea in a wide range of methane-emitting arthropods, combining phylogenomic analysis of isolates and metagenome-assembled genomes (MAGs) with amplicon sequencing of full-length 16S rRNA genes. Our results allowed us to describe numerous new species in hitherto undescribed taxa among the orders Methanobacteriales (Methanacia, Methanarmilla, Methanobaculum, Methanobinarius, Methanocatella, Methanoflexus, Methanorudis, and Methanovirga, all gen. nova), Methanomicrobiales (Methanofilum and Methanorbis, both gen. nova), Methanosarcinales (Methanofrustulum and Methanolapillus, both gen. nova), Methanomassiliicoccales (Methanomethylophilaceae fam. nov., Methanarcanum, Methanogranum, Methanomethylophilus, Methanomicula, Methanoplasma, Methanoprimaticola, all gen. nova), and the new family Bathycorpusculaceae (Bathycorpusculum gen. nov.). Reclassification of amplicon libraries from this and previous studies using this new taxonomic framework revealed that arthropods harbor only CO2 and methyl-reducing hydrogenotrophic methanogens. Numerous genus-level lineages appear to be present exclusively in arthropods, suggesting long evolutionary trajectories with their termite, cockroach, and millipede hosts, and a radiation into various microhabitats and ecological niches provided by their digestive tracts (e.g., hindgut compartments, gut wall, or anaerobic protists). The distribution patterns among the different host groups are often complex, indicating a mixed mode of transmission and a parallel evolution of invertebrate and vertebrate-associated lineages.

RevDate: 2023-11-29

Sun F, Wang Y, Wang Y, et al (2023)

Insights into the spatial distributions of bacteria, archaea, ammonia-oxidizing bacteria and archaea communities in sediments of Daya Bay, northern South China Sea.

Marine pollution bulletin, 198:115850 pii:S0025-326X(23)01285-7 [Epub ahead of print].

Microbe plays an important role in the biogeochemical cycles of the coastal waters. However, comprehensive information about the microbe in the gulf waters is lacking. This study employed high-throughput sequencing and quantitative PCR (qPCR) to investigate the distribution patterns of bacterial, archaeal, ammonia-oxidizing bacterial (AOB), and archaeal (AOA) communities in Daya Bay. Community compositions and principal coordinates analysis (PCoA) exhibited significant spatial characteristics in the diversity and distributions of bacteria, archaea, AOB, and AOA. Notably, various microbial taxa (bacterial, archaeal, AOB, and AOA) exhibited significant differences in different regions, playing crucial roles in nitrogen, sulfur metabolism, and organic carbon mineralization. Canonical correlation analysis (CCA) or redundancy analysis (RDA) indicated that environmental parameters such as temperature, salinity, nitrate, total nitrogen, silicate, and phosphate strongly influenced the distributions of bacterial, archaeal, AOB, and AOA. This study deepens the understanding of the composition and ecological function of prokaryotes in the bay.

RevDate: 2023-11-29

Huber M, Vogel N, Borst A, et al (2023)

Unidirectional gene pairs in archaea and bacteria require overlaps or very short intergenic distances for translational coupling via termination-reinitiation and often encode subunits of heteromeric complexes.

Frontiers in microbiology, 14:1291523.

Genomes of bacteria and archaea contain a much larger fraction of unidirectional (serial) gene pairs than convergent or divergent gene pairs. Many of the unidirectional gene pairs have short overlaps of -4 nt and -1 nt. As shown previously, translation of the genes in overlapping unidirectional gene pairs is tightly coupled. Two alternative models for the fate of the post-termination ribosome predict either that overlaps or very short intergenic distances are essential for translational coupling or that the undissociated post-termination ribosome can scan through long intergenic regions, up to hundreds of nucleotides. We aimed to experimentally resolve the contradiction between the two models by analyzing three native gene pairs from the model archaeon Haloferax volcanii and three native pairs from Escherichia coli. A two reporter gene system was used to quantify the reinitiation frequency, and several stop codons in the upstream gene were introduced to increase the intergenic distances. For all six gene pairs from two species, an extremely strong dependence of the reinitiation efficiency on the intergenic distance was unequivocally demonstrated, such that even short intergenic distances of about 20 nt almost completely abolished translational coupling. Bioinformatic analysis of the intergenic distances in all unidirectional gene pairs in the genomes of H. volcanii and E. coli and in 1,695 prokaryotic species representative of 49 phyla showed that intergenic distances of -4 nt or -1 nt (= short gene overlaps of 4 nt or 1 nt) were by far most common in all these groups of archaea and bacteria. A small set of genes in E. coli, but not in H. volcanii, had intergenic distances of around +10 nt. Our experimental and bioinformatic analyses clearly show that translational coupling requires short gene overlaps, whereas scanning of intergenic regions by the post-termination ribosome occurs rarely, if at all. Short overlaps are enriched among genes that encode subunits of heteromeric complexes, and co-translational complex formation requiring precise subunit stoichiometry likely confers an evolutionary advantage that drove the formation and conservation of overlapping gene pairs during evolution.

RevDate: 2023-11-29
CmpDate: 2023-11-29

Mara P, Geller-McGrath D, Edgcomb V, et al (2023)

Metagenomic profiles of archaea and bacteria within thermal and geochemical gradients of the Guaymas Basin deep subsurface.

Nature communications, 14(1):7768.

Previous studies of microbial communities in subseafloor sediments reported that microbial abundance and diversity decrease with sediment depth and age, and microbes dominating at depth tend to be a subset of the local seafloor community. However, the existence of geographically widespread, subsurface-adapted specialists is also possible. Here, we use metagenomic and metatranscriptomic analyses of the hydrothermally heated, sediment layers of Guaymas Basin (Gulf of California, Mexico) to examine the distribution and activity patterns of bacteria and archaea along thermal, geochemical and cell count gradients. We find that the composition and distribution of metagenome-assembled genomes (MAGs), dominated by numerous lineages of Chloroflexota and Thermoproteota, correlate with biogeochemical parameters as long as temperatures remain moderate, but downcore increasing temperatures beyond ca. 45 ºC override other factors. Consistently, MAG size and diversity decrease with increasing temperature, indicating a downcore winnowing of the subsurface biosphere. By contrast, specific archaeal MAGs within the Thermoproteota and Hadarchaeota increase in relative abundance and in recruitment of transcriptome reads towards deeper, hotter sediments, marking the transition towards a specialized deep, hot biosphere.

RevDate: 2023-11-27
CmpDate: 2023-11-27

Yang Y, Liu H, Zhang Y, et al (2023)

Contribution of ammonia-oxidizing archaea and bacteria to nitrogen transformation in a soil fertilized with urea and organic amendments.

Scientific reports, 13(1):20722.

The contribution of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) is crucial for nitrogen transformation. The effects of four organic amendments (OAs) plus urea on soil nitrogen transformation and the contribution of the ammonia-oxidizing microbial community were investigated using an incubation experiment. The OAs plus urea treatments included pig manure plus urea (PM + U), wheat straw plus urea (WS + U), compost plus urea (CP + U) and improved-compost plus urea (IC + U), while no OAs and urea amended control was noted as CK. The abundance and composition of AOA and AOB were determined using high through-put sequencing. Compared with CK, the OA plus urea treatments significantly enhanced the amount of total mineralized nitrogen released during the incubation process. After incubation, the highest mineralized nitrogen and net nitrogen mineralization was under the PM + U treatment and the lowest was in the WS + U treatment. In conclusion, among all OA plus urea treatments, the microbial biomass nitrogen content was the highest in WS + U treatment and dissolved organic nitrogen content was the highest with the PM + U treatment. Additionally, the abundance of AOB was inhibited in comparison to that of AOA; however, AOB contributed more to nitrification than AOA. Soil NO3[-]-N and dissolved organic nitrogen were the principal components influencing the distribution of AOA and AOB. The result illustrated that the OAs plus urea, especially PM plus urea promoted mineralization to produce more dissolved organic nitrogen and NH4[+]-N, thus accelerating the growth of AOB to strengthen nitrification in soil.

RevDate: 2023-11-25

Zhang Z, Bo L, Wang S, et al (2023)

Multidrug-resistant plasmid RP4 inhibits the nitrogen removal capacity of ammonia-oxidizing archaea, ammonia-oxidizing bacteria, and comammox in activated sludge.

Environmental research pii:S0013-9351(23)02543-4 [Epub ahead of print].

In wastewater treatment plants (WWTPs), ammonia oxidation is primarily carried out by three types of ammonia oxidation microorganisms (AOMs): ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and comammox (CMX). Antibiotic resistance genes (ARGs), which pose an important public health concern, have been identified at every stage of wastewater treatment. However, few studies have focused on the impact of ARGs on ammonia removal performance. Therefore, our study sought to investigate the effect of the representative multidrug-resistant plasmid RP4 on the functional microorganisms involved in ammonia oxidation. Using an inhibitor-based method, we first evaluated the contributions of AOA, AOB, and CMX to ammonia oxidation in activated sludge, which were determined to be 13.7%, 41.1%, and 39.1%, respectively. The inhibitory effects of C2H2, C8H14, and 3,4-dimethylpyrazole phosphate (DMPP) were then validated by qPCR. After adding donor strains to the sludge, fluorescence in situ hybridization (FISH) imaging analysis demonstrated the co-localization of RP4 plasmids and all three AOMs, thus confirming the horizontal gene transfer (HGT) of the RP4 plasmid among these microorganisms. Significant inhibitory effects of the RP4 plasmid on the ammonia nitrogen consumption of AOA, AOB, and CMX were also observed, with inhibition rates of 39.7%, 36.2%, and 49.7%, respectively. Moreover, amoA expression in AOB and CMX was variably inhibited by the RP4 plasmid, whereas AOA amoA expression was not inhibited. These results demonstrate the adverse environmental effects of the RP4 plasmid and provide indirect evidence supporting plasmid-mediated conjugation transfer from bacteria to archaea.

RevDate: 2023-11-25

Borrel G, Fadhlaoui K, Ben Hania W, et al (2023)

Methanomethylophilus alvi gen. nov., sp. nov., a Novel Hydrogenotrophic Methyl-Reducing Methanogenic Archaea of the Order Methanomassiliicoccales Isolated from the Human Gut and Proposal of the Novel Family Methanomethylophilaceae fam. nov.

Microorganisms, 11(11):.

The methanogenic strain Mx-05[T] was isolated from the human fecal microbiome. A phylogenetic analysis based on the 16S rRNA gene and protein marker genes indicated that the strain is affiliated with the order Methanomassiliicoccales. It shares 86.9% 16S rRNA gene sequence identity with Methanomassiliicoccus luminyensis, the only member of this order previously isolated. The cells of Mx-05[T] were non-motile cocci, with a diameter range of 0.4-0.7 μm. They grew anaerobically and reduced methanol, monomethylamine, dimethylamine, and trimethylamine into methane, using H2 as an electron donor. H2/CO2, formate, ethanol, and acetate were not used as energy sources. The growth of Mx-05[T] required an unknown medium factor(s) provided by Eggerthella lenta and present in rumen fluid. Mx-05[T] grew between 30 °C and 40 °C (optimum 37 °C), over a pH range of 6.9-8.3 (optimum pH 7.5), and between 0.02 and 0.34 mol.L[-1] NaCl (optimum 0.12 mol.L[-1] NaCl). The genome is 1.67 Mbp with a G+C content of 55.5 mol%. Genome sequence annotation confirmed the absence of the methyl branch of the H4MPT Wood-Ljungdahl pathway, as described for other Methanomassiliicoccales members. Based on an average nucleotide identity analysis, we propose strain Mx-05[T] as being a novel representative of the order Methanomassiliicoccales, within the novel family Methanomethylophilaceae, for which the name Methanomethylophilus alvi gen. nov, sp. nov. is proposed. The type strain is Mx-05[T] (JCM 31474T).

RevDate: 2023-11-24

Tao S, Veen GFC, Zhang N, et al (2023)

Tree and shrub richness modifies subtropical tree productivity by regulating the diversity and community composition of soil bacteria and archaea.

Microbiome, 11(1):261.

BACKGROUND: Declines in plant biodiversity often have negative consequences for plant community productivity, and it becomes increasingly acknowledged that this may be driven by shifts in soil microbial communities. So far, the role of fungal communities in driving tree diversity-productivity relationships has been well assessed in forests. However, the role of bacteria and archaea, which are also highly abundant in forest soils and perform pivotal ecosystem functions, has been less investigated in this context. Here, we investigated how tree and shrub richness affects stand-level tree productivity by regulating bacterial and archaeal community diversity and composition. We used a landscape-scale, subtropical tree biodiversity experiment (BEF-China) where tree (1, 2, or 4 species) and shrub richness (0, 2, 4, 8 species) were modified.

RESULTS: Our findings indicated a noteworthy decline in soil bacterial α-diversity as tree species richness increased from monoculture to 2- and 4- tree species mixtures, but a significant increase in archaeal α-diversity. Additionally, we observed that the impact of shrub species richness on microbial α-diversity was largely dependent on the level of tree species richness. The increase in tree species richness greatly reduced the variability in bacterial community composition and the complexity of co-occurrence network, but this effect was marginal for archaea. Both tree and shrub species richness increased the stand-level tree productivity by regulating the diversity and composition of bacterial community and archaeal diversity, with the effects being mediated via increases in soil C:N ratios.

CONCLUSIONS: Our findings provide insight into the importance of bacterial and archaeal communities in driving the relationship between plant diversity and productivity in subtropical forests and highlight the necessity for a better understanding of prokaryotic communities in forest soils. Video Abstract.

RevDate: 2023-11-24
CmpDate: 2023-11-23

Gomes-Filho JV, Breuer R, Morales-Filloy HG, et al (2023)

Identification of NAD-RNA species and ADPR-RNA decapping in Archaea.

Nature communications, 14(1):7597.

NAD is a coenzyme central to metabolism that also serves as a 5'-terminal cap for bacterial and eukaryotic transcripts. Thermal degradation of NAD can generate nicotinamide and ADP-ribose (ADPR). Here, we use LC-MS/MS and NAD captureSeq to detect and identify NAD-RNAs in the thermophilic model archaeon Sulfolobus acidocaldarius and in the halophilic mesophile Haloferax volcanii. None of the four Nudix proteins of S. acidocaldarius catalyze NAD-RNA decapping in vitro, but one of the proteins (Saci_NudT5) promotes ADPR-RNA decapping. NAD-RNAs are converted into ADPR-RNAs, which we detect in S. acidocaldarius total RNA. Deletion of the gene encoding the 5'-3' exonuclease Saci-aCPSF2 leads to a 4.5-fold increase in NAD-RNA levels. We propose that the incorporation of NAD into RNA acts as a degradation marker for Saci-aCPSF2. In contrast, ADPR-RNA is processed by Saci_NudT5 into 5'-p-RNAs, providing another layer of regulation for RNA turnover in archaeal cells.

RevDate: 2023-11-21

Sarkar S, Kazarina A, Hansen PM, et al (2023)

Ammonia-oxidizing archaea and bacteria differentially contribute to ammonia oxidation in soil under precipitation gradients and land legacy.

bioRxiv : the preprint server for biology pii:2023.11.08.566028.

BACKGROUND: Global change has accelerated the nitrogen cycle. Soil nitrogen stock degradation by microbes leads to the release of various gases, including nitrous oxide (N 2 O), a potent greenhouse gas. Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) participate in the soil nitrogen cycle, producing N 2 O. There are outstanding questions regarding the impact of environmental processes such as precipitation and land use legacy on AOA and AOB structurally, compositionally, and functionally. To answer these questions, we analyzed field soil cores and soil monoliths under varying precipitation profiles and land legacies.

RESULTS: We resolved 28 AOA and AOB metagenome assembled genomes (MAGs) and found that they were significantly higher in drier environments and differentially abundant in different land use legacies. We further dissected AOA and AOB functional potentials to understand their contribution to nitrogen transformation capabilities. We identified the involvement of stress response genes, differential metabolic functional potentials, and subtle population dynamics under different environmental parameters for AOA and AOB. We observed that AOA MAGs lacked a canonical membrane-bound electron transport chain and F-type ATPase but possessed A/A-type ATPase, while AOB MAGs had a complete complex III module and F-type ATPase, suggesting differential survival strategies of AOA and AOB.

CONCLUSIONS: The outcomes from this study will enable us to comprehend how drought-like environments and land use legacies could impact AOA- and AOB-driven nitrogen transformations in soil.

RevDate: 2023-11-19

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

Corrigendum: Identification of U[p]47 in three thermophilic archaea, one mesophilic archaeon, and one hyperthermophilic bacterium.

RNA (New York, N.Y.), 29(12):1973.

RevDate: 2023-11-14

Zhang IH, Borer B, Zhao R, et al (2023)

Uncultivated DPANN archaea are ubiquitous inhabitants of global oxygen deficient zones with diverse metabolic potential.

bioRxiv : the preprint server for biology pii:2023.10.30.564641.

UNLABELLED: Archaea belonging to the DPANN superphylum have been found within an expanding number of environments and perform a variety of biogeochemical roles, including contributing to carbon, sulfur, and nitrogen cycling. Generally characterized by ultrasmall cell sizes and reduced genomes, DPANN archaea may form mutualistic, commensal, or parasitic interactions with various archaeal and bacterial hosts, influencing the ecology and functioning of microbial communities. While DPANN archaea reportedly comprise 15-26% of the archaeal community within marine oxygen deficient zone (ODZ) water columns, little is known about their metabolic capabilities in these ecosystems. We report 33 novel metagenome-assembled genomes belonging to DPANN phyla Nanoarchaeota, Pacearchaeota, Woesarchaeota, Undinarchaeota, Iainarchaeota, and SpSt-1190 from pelagic ODZs in the Eastern Tropical North Pacific and Arabian Sea. We find these archaea to be permanent, stable residents of all 3 major ODZs only within anoxic depths, comprising up to 1% of the total microbial community and up to 25-50% of archaea. ODZ DPANN appear capable of diverse metabolic functions, including fermentation, organic carbon scavenging, and the cycling of sulfur, hydrogen, and methane. Within a majority of ODZ DPANN, we identify a gene homologous to nitrous oxide reductase. Modeling analyses indicate the feasibility of a nitrous oxide reduction metabolism for host-attached symbionts, and the small genome sizes and reduced metabolic capabilities of most DPANN MAGs suggest host-associated lifestyles within ODZs.

IMPORTANCE: Archaea from the DPANN superphylum have diverse metabolic capabilities and participate in multiple biogeochemical cycles. While metagenomics and enrichments have revealed that many DPANN are characterized by ultrasmall genomes, few biosynthetic genes, and episymbiotic lifestyles, much remains unknown about their biology. We report 33 new DPANN metagenome-assembled genomes originating from the 3 global marine oxygen deficient zones (ODZs), the first from these regions. We survey DPANN abundance and distribution within the ODZ water column, investigate their biosynthetic capabilities, and report potential roles in the cycling of organic carbon, methane, and nitrogen. We test the hypothesis that nitrous oxide reductases found within several ODZ DPANN genomes may enable ultrasmall episymbionts to serve as nitrous oxide consumers when attached to a host nitrous oxide producer. Our results indicate DPANN archaea as ubiquitous residents within the anoxic core of ODZs with the potential to produce or consume key compounds.

RevDate: 2023-11-14
CmpDate: 2023-11-14

Krawczyk A, Gosiewski T, Zapała B, et al (2023)

Alterations in intestinal Archaea composition in pediatric patients with Crohn's disease based on next-generation sequencing - a pilot study.

Gut microbes, 15(2):2276806.

Intestinal dysbiosis can lead to the induction of systemic immune-mediated inflammatory diseases, such as Crohn's disease Although archaea are part of the commensal microbiota, they are still one of the least studied microorganisms. The aim of our study was the standardization of the optimal conditions and primers for sequencing of the gut archaeome using Next Generation Sequencing, and evaluation of the differences between the composition of archaea in patients and healthy volunteers, as well as analysis of the changes that occur in the archaeome of patients depending on disease activity. Newly diagnosed patients were characterized by similar archeal profiles at every taxonomic level as in healthy individuals (the dominance of Methanobacteria at the class level, and Methanobrevibacter at the genus level). In turn, in patients previously diagnosed with Crohn's disease (both in active and remission phase), an increased prevalence of Thermoplasmata, Thermoprotei, Halobacteria (at the class level), and Halococcus, Methanospaera or Picrophilus (at the genus level) were observed. Furthermore, we have found a significant correlation between the patient's parameters and the individual class or species of Archaea. Our study confirms changes in archaeal composition in pediatric patients with Crohn's disease, however, only in long-standing disease. At the beginning of the disease, the archeal profile is similar to that of healthy people. However, in the chronic form of the disease, significant differences in the composition of archaeome begin to appear. It seems that some archaea may be a good indicator of the chronicity and activity of Crohn's disease.

RevDate: 2023-11-13

Zhang T, He W, Liang Q, et al (2023)

Lipidomic diversity and proxy implications of archaea from cold seep sediments of the South China Sea.

Frontiers in microbiology, 14:1241958.

Cold seeps on the continental margins are characterized by intense microbial activities that consume a large portion of methane by anaerobic methanotrophic archaea (ANME) through anaerobic oxidation of methane (AOM). Although ANMEs are known to contain unique ether lipids that may have an important function in marine carbon cycling, their full lipidomic profiles and functional distribution in particular cold-seep settings are still poorly characterized. Here, we combined the 16S rRNA gene sequencing and lipidomic approaches to analyze archaeal communities and their lipids in cold seep sediments with distinct methane supplies from the South China Sea. The archaeal community was dominated by ANME-1 in the moderate seepage area with strong methane emission. Low seepage area presented higher archaeal diversity covering Lokiarchaeia, Bathyarchaeia, and Thermoplasmata. A total of 55 core lipids (CLs) and intact polar lipids (IPLs) of archaea were identified, which included glycerol dialkyl glycerol tetraethers (GDGTs), hydroxy-GDGTs (OH-GDGTs), archaeol (AR), hydroxyarchaeol (OH-AR), and dihydroxyarchaeol (2OH-AR). Diverse polar headgroups constituted the archaeal IPLs. High concentrations of dissolved inorganic carbon (DIC) with depleted δ[13]CDIC and high methane index (MI) values based on both CLs (MICL) and IPLs (MIIPL) indicate that ANMEs were active in the moderate seepage area. The ANME-2 and ANME-3 clades were characterized by enhanced glycosidic and phosphoric diether lipids production, indicating their potential role in coupling carbon and phosphurus cycling in cold seep ecosystems. ANME-1, though representing a smaller proportion of total archaea than ANME-2 and ANME-3 in the low seepage area, showed a positive correlation with MIIPL, indicating a different mechanism contributing to the IPL-GDGT pool. This also suggests that MIIPL could be a sensitive index to trace AOM activities performed by ANME-1. Overall, our study expands the understanding of the archaeal lipid composition in the cold seep and improves the application of MI using intact polar lipids that potentially link to extent ANME activities.

RevDate: 2023-11-13

Manesh MJH, Willard DJ, Lewis AM, et al (2023)

Extremely thermoacidophilic archaea for metal bioleaching: What do their genomes tell Us?.

Bioresource technology, 391(Pt B):129988 pii:S0960-8524(23)01416-5 [Epub ahead of print].

Elevated temperatures favor bioleaching processes through faster kinetics, more favorable mineral chemistry, lower cooling requirements, and less surface passivation. Extremely thermoacidophilic archaea from the order Sulfolobales exhibit novel mechanisms for bioleaching metals from ores and have great potential. Genome sequences of many extreme thermoacidophiles are now available and provide new insights into their biochemistry, metabolism, physiology and ecology as these relate to metal mobilization from ores. Although there are some molecular genetic tools available for extreme thermoacidophiles, further development of these is sorely needed to advance the study and application of these archaea for bioleaching applications. The evolving landscape for bioleaching technologies at high temperatures merits a closer look through a genomic lens at what is currently possible and what lies ahead in terms of new developments and emerging opportunities. The need for critical metals and the diminishing primary deposits for copper should provide incentives for high temperature bioleaching.

RevDate: 2023-11-10

Wang L, Wang Y, Huang X, et al (2022)

Potential metabolic and genetic interaction among viruses, methanogen and methanotrophic archaea, and their syntrophic partners.

ISME communications, 2(1):50.

The metabolism of methane in anoxic ecosystems is mainly mediated by methanogens and methane-oxidizing archaea (MMA), key players in global carbon cycling. Viruses are vital in regulating their host fate and ecological function. However, our knowledge about the distribution and diversity of MMA viruses and their interactions with hosts is rather limited. Here, by searching metagenomes containing mcrA (the gene coding for the α-subunit of methyl-coenzyme M reductase) from a wide variety of environments, 140 viral operational taxonomic units (vOTUs) that potentially infect methanogens or methane-oxidizing archaea were retrieved. Four MMA vOTUs (three infecting the order Methanobacteriales and one infecting the order Methanococcales) were predicted to cross-domain infect sulfate-reducing bacteria. By facilitating assimilatory sulfur reduction, MMA viruses may increase the fitness of their hosts in sulfate-depleted anoxic ecosystems and benefit from synthesis of the sulfur-containing amino acid cysteine. Moreover, cell-cell aggregation promoted by MMA viruses may be beneficial for both the viruses and their hosts by improving infectivity and environmental stress resistance, respectively. Our results suggest a potential role of viruses in the ecological and environmental adaptation of methanogens and methane-oxidizing archaea.

RevDate: 2023-11-03

Lv PL, Jia C, Guo X, et al (2023)

Microbial stratification protects denitrifying anaerobic methane oxidation archaea and bacteria from external oxygen shock in membrane biofilm reactor.

Bioresource technology, 391(Pt A):129966 pii:S0960-8524(23)01394-9 [Epub ahead of print].

Different gradients of dissolved oxygen (DO) regulate the microbial community and nitrogen removal pathways of denitrifying anaerobic methane oxidation (DAMO) and anaerobic ammonium oxidation (Anammox) coupled process in a batch biofilm reactor. Under completely anaerobic condition, approximately 72 mg NO3[-]-N/L was removed at a daily rate of 6.55 mg N/L, whereas a peak accumulation of 95 mg NO3[-]-N/L was observed during DO reached 0.5 mg/L. There is a decrease in the abundance of Candidatus Methylomirabilis (24.1%), Candidatus Methanoperedens (23.3%), and Candidatus Kuenenia (22.6%) to below 5% when DO levels reached 0.2 mg/L. Moreover, key genes associated with the reverse methanogenesis (mcrA) and anaerobic ammonium oxidase (hzo) decreased. These findings indicate that during oxygen shock, methanotrophs and denitrifiers replace Anammox bacteria on the outer sphere of the biofilm, whereas DAMO bacteria and archaea are protected from external oxygen shock due to the microbial stratification of biofilm.

RevDate: 2023-11-08

Vigneron A, Cruaud P, Lovejoy C, et al (2022)

Genomic evidence of functional diversity in DPANN archaea, from oxic species to anoxic vampiristic consortia.

ISME communications, 2(1):4.

DPANN archaea account for half of the archaeal diversity of the biosphere, but with few cultivated representatives, their metabolic potential and environmental functions are poorly understood. The extreme geochemical and environmental conditions in meromictic ice-capped Lake A, in the Canadian High Arctic, provided an isolated, stratified model ecosystem to resolve the distribution and metabolism of uncultured aquatic DPANN archaea living across extreme redox and salinity gradients, from freshwater oxygenated conditions, to saline, anoxic, sulfidic waters. We recovered 28 metagenome-assembled genomes (MAGs) of DPANN archaea that provided genetic insights into their ecological function. Thiosulfate oxidation potential was detected in aerobic Woesearchaeota, whereas diverse metabolic functions were identified in anaerobic DPANN archaea, including degradation and fermentation of cellular compounds, and sulfide and polysulfide reduction. We also found evidence for "vampiristic" metabolism in several MAGs, with genes coding for pore-forming toxins, peptidoglycan degradation, and RNA scavenging. The vampiristic MAGs co-occurred with other DPANNs having complementary metabolic capacities, leading to the possibility that DPANN form interspecific consortia that recycle microbial carbon, nutrients and complex molecules through a DPANN archaeal shunt, adding hidden novel complexity to anaerobic microbial food webs.

RevDate: 2023-11-08

Thomas CM, Taib N, Gribaldo S, et al (2021)

Comparative genomic analysis of Methanimicrococcus blatticola provides insights into host adaptation in archaea and the evolution of methanogenesis.

ISME communications, 1(1):47.

Other than the Methanobacteriales and Methanomassiliicoccales, the characteristics of archaea that inhabit the animal microbiome are largely unknown. Methanimicrococcus blatticola, a member of the Methanosarcinales, currently reunites two unique features within this order: it is a colonizer of the animal digestive tract and can only reduce methyl compounds with H2 for methanogenesis, a increasingly recognized metabolism in the archaea and whose origin remains debated. To understand the origin of these characteristics, we have carried out a large-scale comparative genomic analysis. We infer the loss of more than a thousand genes in M. blatticola, by far the largest genome reduction across all Methanosarcinales. These include numerous elements for sensing the environment and adapting to more stable gut conditions, as well as a significant remodeling of the cell surface components likely involved in host and gut microbiota interactions. Several of these modifications parallel those previously observed in phylogenetically distant archaea and bacteria from the animal microbiome, suggesting large-scale convergent mechanisms of adaptation to the gut. Strikingly, M. blatticola has lost almost all genes coding for the H4MPT methyl branch of the Wood-Ljungdahl pathway (to the exception of mer), a phenomenon never reported before in any member of Class I or Class II methanogens. The loss of this pathway illustrates one of the evolutionary processes that may have led to the emergence of methyl-reducing hydrogenotrophic methanogens, possibly linked to the colonization of organic-rich environments (including the animal gut) where both methyl compounds and hydrogen are abundant.

RevDate: 2023-11-08

Huang L, Chakrabarti S, Cooper J, et al (2021)

Ammonia-oxidizing archaea are integral to nitrogen cycling in a highly fertile agricultural soil.

ISME communications, 1(1):19.

Nitrification is a central process in the global nitrogen cycle, carried out by a complex network of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), complete ammonia-oxidizing (comammox) bacteria, and nitrite-oxidizing bacteria (NOB). Nitrification is responsible for significant nitrogen leaching and N2O emissions and thought to impede plant nitrogen use efficiency in agricultural systems. However, the actual contribution of each nitrifier group to net rates and N2O emissions remain poorly understood. We hypothesized that highly fertile agricultural soils with high organic matter mineralization rates could allow a detailed characterization of N cycling in these soils. Using a combination of molecular and activity measurements, we show that in a mixed AOA, AOB, and comammox community, AOA outnumbered low diversity assemblages of AOB and comammox 50- to 430-fold, and strongly dominated net nitrification activities with low N2O yields between 0.18 and 0.41 ng N2O-N per µg NOx-N in cropped, fallow, as well as native soil. Nitrification rates were not significantly different in plant-covered and fallow plots. Mass balance calculations indicated that plants relied heavily on nitrate, and not ammonium as primary nitrogen source in these soils. Together, these results imply AOA as integral part of the nitrogen cycle in a highly fertile agricultural soil.

RevDate: 2023-11-08

Shafiee RT, Diver PJ, Snow JT, et al (2021)

Marine ammonia-oxidising archaea and bacteria occupy distinct iron and copper niches.

ISME communications, 1(1):1.

Ammonia oxidation by archaea and bacteria (AOA and AOB), is the first step of nitrification in the oceans. As AOA have an ammonium affinity 200-fold higher than AOB isolates, the chemical niche allowing AOB to persist in the oligotrophic ocean remains unclear. Here we show that marine isolates, Nitrosopumilus maritimus strain SCM1 (AOA) and Nitrosococcus oceani strain C-107 (AOB) have contrasting physiologies in response to the trace metals iron (Fe) and copper (Cu), holding potential implications for their niche separation in the oceans. A greater affinity for unchelated Fe may allow AOB to inhabit shallower, euphotic waters where ammonium supply is high, but competition for Fe is rife. In contrast to AOB, AOA isolates have a greater affinity and toxicity threshold for unchelated Cu providing additional explanation to the greater success of AOA in the marine environment where Cu availability can be highly variable. Using comparative genomics, we predict that the proteomic and metal transport basis giving rise to contrasting physiologies in isolates is widespread across phylogenetically diverse marine AOA and AOB that are not yet available in pure culture. Our results develop the testable hypothesis that ammonia oxidation may be limited by Cu in large tracts of the open ocean and suggest a relatively earlier emergence of AOB than AOA when considered in the context of evolving trace metal availabilities over geologic time.

RevDate: 2023-11-02

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

Salinigranum marinum sp. nov. and Halohasta salina sp. nov., halophilic archaea isolated from sediment of a marine saltern and inland saline soil.

International journal of systematic and evolutionary microbiology, 73(11):.

Two halophilic archaeal strains, ZS-10[T] and GSL13[T], were isolated from the Zhoushan marine saltern in Zhejiang, and an inland saline soil from the Tarim Basin, Xinjiang, PR China, respectively. The cells of strain ZS-10[T] were pleomorphic while those of strain GSL13[T] were rod-shaped. Both of them stained Gram-negative and formed red-pigmented colonies on agar plates and their cells lysed in distilled water. The optimum growth of strain ZS-10[T] was observed at 40 °C, 3.4 M NaCl, 0.03 M MgCl2 and pH 7.5, while that of strain GSL13[T] was at 37 °C, 3.1 M NaCl, 0.5 M MgCl2 and pH 7.5. Phylogenetic and phylogenomic analyses indicated that these two strains were related to Salinigranum and Halohasta, respectively. Strains ZS-10[T] and GSL13[T] could be differentiated from the current members of Salinigranum and Halohasta based on the comparison of diverse phenotypic characteristics. The average amino acid identity, average nucleotide identity and digital DNA-DNA hybridization values among strain ZS-10[T] and current species of Salinigranum were 75.8-78.6 %, 80.6-81.9 % and 24.3-26.1 %, respectively. These values between strain GSL13[T] and current species of Halohasta were 78.4-80.8 %, 79.8-82.8% and 22.7-25.7 %, respectively, clearly below the threshold values for species demarcation. The polar lipids of strain ZS-10[T] were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me) and sulphated mannosyl glucosyl diether (S-DGD-1), while those of strain GSL13[T] were phosphatidic acid, PG, PGP-Me, phosphatidylglycerol sulphate and S-DGD-1. The polar lipid profile of strain GSL13[T] was identical to those of Halohasta, whereas strain ZS-10[T] did not contain the minor glycolipids detected in the current Salinigranum species. The phenotypic, phylogenetic and genome-based results suggested that strains ZS-10[T] (=CGMCC 1.12868[T]=JCM 30241[T]) and GSL13[T] (=CGMCC 1.15214[T]=JCM 30841[T]) represent two novel species, for which the names Salinigranum marinum sp. nov. and Halohasta salina sp. nov. are proposed.

RevDate: 2023-11-02

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

Corrigendum: Proposed minimal standards for description of methanogenic archaea.

International journal of systematic and evolutionary microbiology, 73(11):.

RevDate: 2023-11-02

Romero P, Belanche A, Jiménez E, et al (2023)

Rumen microbial degradation of bromoform from red seaweed (Asparagopsis taxiformis) and the impact on rumen fermentation and methanogenic archaea.

Journal of animal science and biotechnology, 14(1):133.

BACKGROUND: The red macroalgae Asparagopsis is an effective methanogenesis inhibitor due to the presence of halogenated methane (CH4) analogues, primarily bromoform (CHBr3). This study aimed to investigate the degradation process of CHBr3 from A. taxiformis in the rumen and whether this process is diet-dependent. An in vitro batch culture system was used according to a 2 × 2 factorial design, assessing two A. taxiformis inclusion rates [0 (CTL) and 2% DM diet (AT)] and two diets [high-concentrate (HC) and high-forage diet (HF)]. Incubations lasted for 72 h and samples of headspace and fermentation liquid were taken at 0, 0.5, 1, 3, 6, 8, 12, 16, 24, 48 and 72 h to assess the pattern of degradation of CHBr3 into dibromomethane (CH2Br2) and fermentation parameters. Additionally, an in vitro experiment with pure cultures of seven methanogens strains (Methanobrevibacter smithii, Methanobrevibacter ruminantium, Methanosphaera stadtmanae, Methanosarcina barkeri, Methanobrevibacter millerae, Methanothermobacter wolfei and Methanobacterium mobile) was conducted to test the effects of increasing concentrations of CHBr3 (0.4, 2, 10 and 50 µmol/L).

RESULTS: The addition of AT significantly decreased CH4 production (P = 0.002) and the acetate:propionate ratio (P = 0.003) during a 72-h incubation. The concentrations of CHBr3 showed a rapid decrease with nearly 90% degraded within the first 3 h of incubation. On the contrary, CH2Br2 concentration quickly increased during the first 6 h and then gradually decreased towards the end of the incubation. Neither CHBr3 degradation nor CH2Br2 synthesis were affected by the type of diet used as substrate, suggesting that the fermentation rate is not a driving factor involved in CHBr3 degradation. The in vitro culture of methanogens showed a dose-response effect of CHBr3 by inhibiting the growth of M. smithii, M. ruminantium, M. stadtmanae, M. barkeri, M. millerae, M. wolfei, and M. mobile.

CONCLUSIONS: The present work demonstrated that CHBr3 from A. taxiformis is quickly degraded to CH2Br2 in the rumen and that the fermentation rate promoted by different diets is not a driving factor involved in CHBr3 degradation.

RevDate: 2023-10-30
CmpDate: 2023-10-30

Ullah N, Yang N, Guan Z, et al (2023)

Comparative Analysis and Phylogenetic Insights of Cas14-Homology Proteins in Bacteria and Archaea.

Genes, 14(10):.

Type-V-F Cas12f proteins, also known as Cas14, have drawn significant interest within the diverse CRISPR-Cas nucleases due to their compact size. This study involves analyzing and comparing Cas14-homology proteins in prokaryotic genomes through mining, sequence comparisons, a phylogenetic analysis, and an array/repeat analysis. In our analysis, we identified and mined a total of 93 Cas14-homology proteins that ranged in size from 344 aa to 843 aa. The majority of the Cas14-homology proteins discovered in this analysis were found within the Firmicutes group, which contained 37 species, representing 42% of all the Cas14-homology proteins identified. In archaea, the DPANN group had the highest number of species containing Cas14-homology proteins, a total of three species. The phylogenetic analysis results demonstrate the division of Cas14-homology proteins into three clades: Cas14-A, Cas14-B, and Cas14-U. Extensive similarity was observed at the C-terminal end (CTD) through a domain comparison of the three clades, suggesting a potentially shared mechanism of action due to the presence of cutting domains in that region. Additionally, a sequence similarity analysis of all the identified Cas14 sequences indicated a low level of similarity (18%) between the protein variants. The analysis of repeats/arrays in the extended nucleotide sequences of the identified Cas14-homology proteins highlighted that 44 out of the total mined proteins possessed CRISPR-associated repeats, with 20 of them being specific to Cas14. Our study contributes to the increased understanding of Cas14 proteins across prokaryotic genomes. These homologous proteins have the potential for future applications in the mining and engineering of Cas14 proteins.

RevDate: 2023-10-27

Notaro A, Zaretsky M, Molinaro A, et al (2023)

N-glycosylation in Archaea: Unusual sugars and unique modifications.

Carbohydrate research, 534:108963 pii:S0008-6215(23)00225-2 [Epub ahead of print].

Archaea are microorganisms that comprise a distinct branch of the universal tree of life and which are best known as extremophiles, residing in a variety of environments characterized by harsh physical conditions. One seemingly universal trait of Archaea is the ability to perform N-glycosylation. At the same time, archaeal N-linked glycans present variety in terms of both composition and architecture not seen in the parallel eukaryal or bacterial processes. In this mini-review, many of the unique and unusual sugars found in archaeal N-linked glycans as identified by nuclear magnetic resonance spectroscopy are described.


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.

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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.

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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.

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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.

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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 large collection of user-selected side-by-side timelines (e.g., all science vs. all other categories, or arts and culture vs. world history), designed to provide a comparative context for appreciating world events.


Biographical information about many key scientists (e.g., Walter Sutton).

Selected Bibliographies

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

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