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Xu M, Liu M, Liu T, Pan X, Ren Q, Han T, Gou L. HigA2 (Rv2021c) Is a Transcriptional Regulator with Multiple Regulatory Targets in Mycobacterium tuberculosis. Microorganisms 2024; 12:1244. [PMID: 38930627 PMCID: PMC11205783 DOI: 10.3390/microorganisms12061244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2024] [Revised: 06/17/2024] [Accepted: 06/18/2024] [Indexed: 06/28/2024] Open
Abstract
Toxin-antitoxin (TA) systems are the major mechanism for persister formation in Mycobacterium tuberculosis (Mtb). Previous studies found that HigBA2 (Rv2022c-Rv2021c), a predicted type II TA system of Mtb, could be activated for transcription in response to multiple stresses such as anti-tuberculosis drugs, nutrient starvation, endure hypoxia, acidic pH, etc. In this study, we determined the binding site of HigA2 (Rv2021c), which is located in the coding region of the upstream gene higB2 (Rv2022c), and the conserved recognition motif of HigA2 was characterized via oligonucleotide mutation. Eight binding sites of HigA2 were further found in the Mtb genome according to the conserved motif. RT-PCR showed that HigA2 can regulate the transcription level of all eight of these genes and three adjacent downstream genes. DNA pull-down experiments showed that twelve functional regulators sense external regulatory signals and may regulate the transcription of the HigBA2 system. Of these, Rv0903c, Rv0744c, Rv0474, Rv3124, Rv2603c, and Rv3583c may be involved in the regulation of external stress signals. In general, we identified the downstream target genes and possible upstream regulatory genes of HigA2, which paved the way for the illustration of the persistence establishment mechanism in Mtb.
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Affiliation(s)
- Mingyan Xu
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Meikun Liu
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Tong Liu
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Xuemei Pan
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Qi Ren
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Tiesheng Han
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Lixia Gou
- School of Life Science, North China University of Science and Technology, Tangshan 063210, China
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2
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Leung PM, Grinter R, Tudor-Matthew E, Lingford JP, Jimenez L, Lee HC, Milton M, Hanchapola I, Tanuwidjaya E, Kropp A, Peach HA, Carere CR, Stott MB, Schittenhelm RB, Greening C. Trace gas oxidation sustains energy needs of a thermophilic archaeon at suboptimal temperatures. Nat Commun 2024; 15:3219. [PMID: 38622143 PMCID: PMC11018855 DOI: 10.1038/s41467-024-47324-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/22/2024] [Indexed: 04/17/2024] Open
Abstract
Diverse aerobic bacteria use atmospheric hydrogen (H2) and carbon monoxide (CO) as energy sources to support growth and survival. Such trace gas oxidation is recognised as a globally significant process that serves as the main sink in the biogeochemical H2 cycle and sustains microbial biodiversity in oligotrophic ecosystems. However, it is unclear whether archaea can also use atmospheric H2. Here we show that a thermoacidophilic archaeon, Acidianus brierleyi (Thermoproteota), constitutively consumes H2 and CO to sub-atmospheric levels. Oxidation occurs across a wide range of temperatures (10 to 70 °C) and enhances ATP production during starvation-induced persistence under temperate conditions. The genome of A. brierleyi encodes a canonical CO dehydrogenase and four distinct [NiFe]-hydrogenases, which are differentially produced in response to electron donor and acceptor availability. Another archaeon, Metallosphaera sedula, can also oxidize atmospheric H2. Our results suggest that trace gas oxidation is a common trait of Sulfolobales archaea and may play a role in their survival and niche expansion, including during dispersal through temperate environments.
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Affiliation(s)
- Pok Man Leung
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
| | - Rhys Grinter
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Eve Tudor-Matthew
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - James P Lingford
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Luis Jimenez
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Han-Chung Lee
- Monash Proteomics and Metabolomics Platform and Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Michael Milton
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Iresha Hanchapola
- Monash Proteomics and Metabolomics Platform and Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Erwin Tanuwidjaya
- Monash Proteomics and Metabolomics Platform and Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Ashleigh Kropp
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Hanna A Peach
- Geomicrobiology Research Group, Department of Geothermal Sciences, Te Pū Ao | GNS Science, Wairakei, Taupō, 3377, Aotearoa New Zealand
| | - Carlo R Carere
- Geomicrobiology Research Group, Department of Geothermal Sciences, Te Pū Ao | GNS Science, Wairakei, Taupō, 3377, Aotearoa New Zealand
- Te Tari Pūhanga Tukanga Matū | Department of Chemical and Process Engineering, Te Whare Wānanga o Waitaha | University of Canterbury, Christchurch, 8140, Aotearoa New Zealand
| | - Matthew B Stott
- Geomicrobiology Research Group, Department of Geothermal Sciences, Te Pū Ao | GNS Science, Wairakei, Taupō, 3377, Aotearoa New Zealand
- Te Kura Pūtaiao Koiora | School of Biological Sciences, Te Whare Wānanga o Waitaha | University of Canterbury, Christchurch, 8140, Aotearoa New Zealand
| | - Ralf B Schittenhelm
- Monash Proteomics and Metabolomics Platform and Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
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3
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Sarkar J, Mondal M, Bhattacharya S, Dutta S, Chatterjee S, Mondal N, N S, Peketi A, Mazumdar A, Ghosh W. Extremely oligotrophic and complex-carbon-degrading microaerobic bacteria from Arabian Sea oxygen minimum zone sediments. Arch Microbiol 2024; 206:179. [PMID: 38498215 DOI: 10.1007/s00203-024-03875-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 03/20/2024]
Abstract
Sediments underlying marine hypoxic zones are huge sinks of unreacted complex organic matter, where despite acute O2 limitation, obligately aerobic bacteria thrive, and steady depletion of organic carbon takes place within a few meters below the seafloor. However, little knowledge exists about the sustenance and complex carbon degradation potentials of aerobic chemoorganotrophs in these sulfidic ecosystems. We isolated and characterized a number of aerobic bacterial chemoorganoheterotrophs from across a ~ 3 m sediment horizon underlying the perennial hypoxic zone of the eastern Arabian Sea. High levels of sequence correspondence between the isolates' genomes and the habitat's metagenomes and metatranscriptomes illustrated that the strains were widespread and active across the sediment cores explored. The isolates catabolized several complex organic compounds of marine and terrestrial origins in the presence of high or low, but not zero, O2. Some of them could also grow anaerobically on yeast extract or acetate by reducing nitrate and/or nitrite. Fermentation did not support growth, but enabled all the strains to maintain a fraction of their cell populations over prolonged anoxia. Under extreme oligotrophy, limited growth followed by protracted stationary phase was observed for all the isolates at low cell density, amid high or low, but not zero, O2 concentration. While population control and maintenance could be particularly useful for the strains' survival in the critically carbon-depleted layers below the explored sediment depths (core-bottom organic carbon: 0.5-1.0% w/w), metagenomic data suggested that in situ anoxia could be surmounted via potential supplies of cryptic O2 from previously reported sources such as Nitrosopumilus species.
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Affiliation(s)
- Jagannath Sarkar
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India.
| | - Mahamadul Mondal
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
| | - Sabyasachi Bhattacharya
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
- National Institute of Biomedical Genomics, Kalyani, West Bengal, India
| | - Subhajit Dutta
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
| | - Sumit Chatterjee
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
| | - Nibendu Mondal
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
- International Institute of Innovation and Technology, Kolkata, West Bengal, India
| | - Saran N
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
| | - Aditya Peketi
- Geological Oceanography, CSIR National Institute of Oceanography, Dona Paula, Goa, 403004, India
| | - Aninda Mazumdar
- Geological Oceanography, CSIR National Institute of Oceanography, Dona Paula, Goa, 403004, India
| | - Wriddhiman Ghosh
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India.
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Valentin-Alvarado LE, Fakra SC, Probst AJ, Giska JR, Jaffe AL, Oltrogge LM, West-Roberts J, Rowland J, Manga M, Savage DF, Greening C, Baker BJ, Banfield JF. Autotrophic biofilms sustained by deeply sourced groundwater host diverse bacteria implicated in sulfur and hydrogen metabolism. MICROBIOME 2024; 12:15. [PMID: 38273328 PMCID: PMC10811913 DOI: 10.1186/s40168-023-01704-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 10/18/2023] [Indexed: 01/27/2024]
Abstract
BACKGROUND Biofilms in sulfide-rich springs present intricate microbial communities that play pivotal roles in biogeochemical cycling. We studied chemoautotrophically based biofilms that host diverse CPR bacteria and grow in sulfide-rich springs to investigate microbial controls on biogeochemical cycling. RESULTS Sulfide springs biofilms were investigated using bulk geochemical analysis, genome-resolved metagenomics, and scanning transmission X-ray microscopy (STXM) at room temperature and 87 K. Chemolithotrophic sulfur-oxidizing bacteria, including Thiothrix and Beggiatoa, dominate the biofilms, which also contain CPR Gracilibacteria, Absconditabacteria, Saccharibacteria, Peregrinibacteria, Berkelbacteria, Microgenomates, and Parcubacteria. STXM imaging revealed ultra-small cells near the surfaces of filamentous bacteria that may be CPR bacterial episymbionts. STXM and NEXAFS spectroscopy at carbon K and sulfur L2,3 edges show that filamentous bacteria contain protein-encapsulated spherical elemental sulfur granules, indicating that they are sulfur oxidizers, likely Thiothrix. Berkelbacteria and Moranbacteria in the same biofilm sample are predicted to have a novel electron bifurcating group 3b [NiFe]-hydrogenase, putatively a sulfhydrogenase, potentially linked to sulfur metabolism via redox cofactors. This complex could potentially contribute to symbioses, for example, with sulfur-oxidizing bacteria such as Thiothrix that is based on cryptic sulfur cycling. One Doudnabacteria genome encodes adjacent sulfur dioxygenase and rhodanese genes that may convert thiosulfate to sulfite. We find similar conserved genomic architecture associated with CPR bacteria from other sulfur-rich subsurface ecosystems. CONCLUSIONS Our combined metagenomic, geochemical, spectromicroscopic, and structural bioinformatics analyses of biofilms growing in sulfide-rich springs revealed consortia that contain CPR bacteria and sulfur-oxidizing Proteobacteria, including Thiothrix, and bacteria from a new family within Beggiatoales. We infer roles for CPR bacteria in sulfur and hydrogen cycling. Video Abstract.
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Affiliation(s)
- Luis E Valentin-Alvarado
- Graduate Group in Microbiology, University of California, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Sirine C Fakra
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Alexander J Probst
- Earth and Planetary Science, University of California, Berkeley, CA, USA
- Environmental Metagenomics, Research Center One Health Ruhr of the University Alliance Ruhr, Faculty of Chemistry,, University of Duisburg-Essen, Essen, Essen, Germany
| | - Jonathan R Giska
- Earth and Planetary Science, University of California, Berkeley, CA, USA
- Cleaner Air Oregon Program, Oregon Department of Environmental Quality, Portland, USA
| | - Alexander L Jaffe
- Graduate Group in Microbiology, University of California, Berkeley, CA, USA
| | - Luke M Oltrogge
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, 94720, USA
| | - Jacob West-Roberts
- Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
| | - Joel Rowland
- Earth and Planetary Science, University of California, Berkeley, CA, USA
- Earth and Env. Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Michael Manga
- Earth and Planetary Science, University of California, Berkeley, CA, USA
- University of Duisburg-Essen, Universitätsstraße 5, 45141, Essen, Germany
| | - David F Savage
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, 94720, USA
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Brett J Baker
- Department of Integrative Biology, University of Texas, Austin, USA
- Department of Marine Science, University of Texas, Austin, USA
| | - Jillian F Banfield
- Innovative Genomics Institute, University of California, Berkeley, CA, USA.
- Earth and Planetary Science, University of California, Berkeley, CA, USA.
- Environmental Science, Policy and Management, University of California, Berkeley, CA, USA.
- Department of Marine Science, University of Texas, Austin, USA.
- Energy Geoscience Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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5
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Reis PCJ, Tsuji JM, Weiblen C, Schiff SL, Scott M, Stein LY, Neufeld JD. Enigmatic persistence of aerobic methanotrophs in oxygen-limiting freshwater habitats. THE ISME JOURNAL 2024; 18:wrae041. [PMID: 38470309 PMCID: PMC11008690 DOI: 10.1093/ismejo/wrae041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/06/2024] [Accepted: 03/13/2024] [Indexed: 03/13/2024]
Abstract
Methanotrophic bacteria mitigate emissions of the potent greenhouse gas methane (CH4) from a variety of anthropogenic and natural sources, including freshwater lakes, which are large sources of CH4 on a global scale. Despite a dependence on dioxygen (O2) for CH4 oxidation, abundant populations of putatively aerobic methanotrophs have been detected within microoxic and anoxic waters and sediments of lakes. Experimental work has demonstrated active aerobic methanotrophs under those conditions, but how they are able to persist and oxidize CH4 under O2 deficiency remains enigmatic. In this review, we discuss possible mechanisms that underpin the persistence and activity of aerobic methanotrophs under O2-limiting conditions in freshwater habitats, particularly lakes, summarize experimental evidence for microbial oxidation of CH4 by aerobic bacteria under low or no O2, and suggest future research directions to further explore the ecology and metabolism of aerobic methanotrophs in O2-limiting environments.
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Affiliation(s)
- Paula C J Reis
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Jackson M Tsuji
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, Institute for Extra-cutting-edge Science and Technology Avant-garde Research, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan
| | - Cerrise Weiblen
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Sherry L Schiff
- Department of Earth & Environmental Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Matthew Scott
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Lisa Y Stein
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Josh D Neufeld
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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Keller LML, Flattich K, Weber-Ban E. Novel WYL domain-containing transcriptional activator acts in response to genotoxic stress in rapidly growing mycobacteria. Commun Biol 2023; 6:1222. [PMID: 38042942 PMCID: PMC10693628 DOI: 10.1038/s42003-023-05592-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 11/15/2023] [Indexed: 12/04/2023] Open
Abstract
The WYL domain is a nucleotide-sensing module that controls the activity of transcription factors involved in the regulation of DNA damage response and phage defense mechanisms in bacteria. In this study, we investigated a WYL domain-containing transcription factor in Mycobacterium smegmatis that we termed stress-involved WYL domain-containing regulator (SiwR). We found that SiwR controls adjacent genes that belong to the DinB/YfiT-like putative metalloenzymes superfamily by upregulating their expression in response to various genotoxic stress conditions, including upon exposure to H2O2 or the natural antibiotic zeocin. We show that SiwR binds different forms of single-stranded DNA (ssDNA) with high affinity, primarily through its characteristic WYL domain. In combination with complementation studies of a M. smegmatis siwR deletion strain, our findings support a role of the WYL domains as signal-sensing activity switches of WYL domain-containing transcription factors (WYL TFs). Our study provides evidence that WYL TFs are involved in the adaptation of bacteria to changing environments and encountered stress conditions.
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Affiliation(s)
| | - Kim Flattich
- Institute of Molecular Biology and Biophysics, ETH Zurich, 8093, Zurich, Switzerland
| | - Eilika Weber-Ban
- Institute of Molecular Biology and Biophysics, ETH Zurich, 8093, Zurich, Switzerland.
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7
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Rubin-Blum M, Yudkovsky Y, Marmen S, Raveh O, Amrani A, Kutuzov I, Guy-Haim T, Rahav E. Tar patties are hotspots of hydrocarbon turnover and nitrogen fixation during a nearshore pollution event in the oligotrophic southeastern Mediterranean Sea. MARINE POLLUTION BULLETIN 2023; 197:115747. [PMID: 37995430 DOI: 10.1016/j.marpolbul.2023.115747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/29/2023] [Accepted: 11/01/2023] [Indexed: 11/25/2023]
Abstract
Weathered oil, that is, tar, forms hotspots of hydrocarbon degradation by complex biota in marine environment. Here, we used marker gene sequencing and metagenomics to characterize the communities of bacteria, archaea and eukaryotes that colonized tar patties and control samples (wood, plastic), collected in the littoral following an offshore spill in the warm, oligotrophic southeastern Mediterranean Sea (SEMS). We show potential aerobic and anaerobic hydrocarbon catabolism niches on tar interior and exterior, linking carbon, sulfur and nitrogen cycles. Alongside aromatics and larger alkanes, short-chain alkanes appear to fuel dominant populations, both the aerobic clade UBA5335 (Macondimonas), anaerobic Syntropharchaeales, and facultative Mycobacteriales. Most key organisms, including the hydrocarbon degraders and cyanobacteria, have the potential to fix dinitrogen, potentially alleviating the nitrogen limitation of hydrocarbon degradation in the SEMS. We highlight the complexity of these tar-associated communities, where bacteria, archaea and eukaryotes co-exist, likely exchanging metabolites and competing for resources and space.
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Affiliation(s)
- Maxim Rubin-Blum
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel.
| | - Yana Yudkovsky
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
| | - Sophi Marmen
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
| | - Ofrat Raveh
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
| | - Alon Amrani
- Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ilya Kutuzov
- Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tamar Guy-Haim
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
| | - Eyal Rahav
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
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Aoki M, Takemura Y, Kawakami S, Yoochatchaval W, Tran P. T, Tomioka N, Ebie Y, Syutsubo K. Quantitative detection and reduction of potentially pathogenic bacterial groups of Aeromonas, Arcobacter, Klebsiella pneumoniae species complex, and Mycobacterium in wastewater treatment facilities. PLoS One 2023; 18:e0291742. [PMID: 37768925 PMCID: PMC10538766 DOI: 10.1371/journal.pone.0291742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 09/05/2023] [Indexed: 09/30/2023] Open
Abstract
Water quality parameters influence the abundance of pathogenic bacteria. The genera Aeromonas, Arcobacter, Klebsiella, and Mycobacterium are among the representative pathogenic bacteria identified in wastewater. However, information on the correlations between water quality and the abundance of these bacteria, as well as their reduction rate in existing wastewater treatment facilities (WTFs), is lacking. Hence, this study aimed to determine the abundance and reduction rates of these bacterial groups in WTFs. Sixty-eight samples (34 influent and 34 non-disinfected, treated, effluent samples) were collected from nine WTFs in Japan and Thailand. 16S rRNA gene amplicon sequencing analysis revealed the presence of Aeromonas, Arcobacter, and Mycobacterium in all influent wastewater and treated effluent samples. Quantitative real-time polymerase chain reaction (qPCR) was used to quantify the abundance of Aeromonas, Arcobacter, Klebsiella pneumoniae species complex (KpSC), and Mycobacterium. The geometric mean abundances of Aeromonas, Arcobacter, KpSC, and Mycobacterium in the influent wastewater were 1.2 × 104-2.4 × 105, 1.0 × 105-4.5 × 106, 3.6 × 102-4.3 × 104, and 6.9 × 103-5.5 × 104 cells mL-1, respectively, and their average log reduction values were 0.77-2.57, 1.00-3.06, 1.35-3.11, and -0.67-1.57, respectively. Spearman's rank correlation coefficients indicated significant positive or negative correlations between the abundances of the potentially pathogenic bacterial groups and Escherichia coli as well as water quality parameters, namely, chemical/biochemical oxygen demand, total nitrogen, nitrate-nitrogen, nitrite-nitrogen, ammonium-nitrogen, suspended solids, volatile suspended solids, and oxidation-reduction potential. This study provides valuable information on the development and appropriate management of WTFs to produce safe, hygienic water.
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Affiliation(s)
- Masataka Aoki
- Regional Environment Conservation Division, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
| | - Yasuyuki Takemura
- Regional Environment Conservation Division, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
| | - Shuji Kawakami
- Department of Civil Engineering, National Institute of Technology (KOSEN), Nagaoka College, Nagaoka, Niigata, Japan
| | - Wilasinee Yoochatchaval
- Department of Environmental Engineering, Faculty of Engineering, Kasetsart University, Bangkok, Thailand
| | - Thao Tran P.
- Regional Environment Conservation Division, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
| | - Noriko Tomioka
- Regional Environment Conservation Division, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
| | - Yoshitaka Ebie
- Material Cycles Division, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
| | - Kazuaki Syutsubo
- Regional Environment Conservation Division, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
- Research Center of Water Environment Technology, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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9
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Kiyama T, Tokunaga A, Naji A, Barbul A. Changes in the negative logarithm of end-tidal hydrogen partial pressure indicate the variation of electrode potential in healthy Japanese subjects. Sci Rep 2023; 13:15473. [PMID: 37726384 PMCID: PMC10509160 DOI: 10.1038/s41598-023-42651-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 09/13/2023] [Indexed: 09/21/2023] Open
Abstract
Molecular hydrogen (H2) is produced by human colon microbiomes and exhaled. End-tidal H2 sampling is a simple method of measuring alveolar H2. The logarithm of the hydrogen ion (H+)/H2 ratio suggests the electrode potential in the solution according to the Nernst equation. As pH is defined as the negative logarithm of the H+ concentration, pH2 is defined as the negative logarithm of the H2 effective pressure in this study. We investigated whether changes in pH2 indicated the variation of electrode potential in the solution and whether changes in end-tidal pH2 could be measured using a portable breath H2 sensor. Changes in the electrode potential were proportional to ([Formula: see text]) in phosphate-buffered solution (pH = 7.1). End-tidal H2 was measured in the morning (baseline) and at noon (after daily activities) in 149 healthy Japanese subjects using a handheld H2 sensor. The median pH2 at the baseline was 4.89, and it increased by 0.15 after daily activities. The variation of electrode potential was obtained by multiplying the pH2 difference, which suggested approximately + 4.6 mV oxidation after daily activities. These data suggested that changes in end-tidal pH2 indicate the variation of electrode potential during daily activities in healthy human subjects.
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Affiliation(s)
- Teruo Kiyama
- Department of Gastrointestinal and Hepato-Biliary-Pancreatic Surgery, Nippon Medical School, Bunkyo, Tokyo, Japan.
- Department of Surgery, TMG Asaka Medical Center, Asaka, Saitama, Japan.
- Department of Surgery, Musashino Tokushukai Hospital, Nishi-Tokyo, Tokyo, Japan.
| | - Akira Tokunaga
- Department of Gastrointestinal and Hepato-Biliary-Pancreatic Surgery, Nippon Medical School, Bunkyo, Tokyo, Japan
| | - Abumrad Naji
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Adrian Barbul
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN, USA
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10
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Wright CL, Lehtovirta-Morley LE. Nitrification and beyond: metabolic versatility of ammonia oxidising archaea. THE ISME JOURNAL 2023; 17:1358-1368. [PMID: 37452095 PMCID: PMC10432482 DOI: 10.1038/s41396-023-01467-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/09/2023] [Accepted: 06/21/2023] [Indexed: 07/18/2023]
Abstract
Ammonia oxidising archaea are among the most abundant living organisms on Earth and key microbial players in the global nitrogen cycle. They carry out oxidation of ammonia to nitrite, and their activity is relevant for both food security and climate change. Since their discovery nearly 20 years ago, major insights have been gained into their nitrogen and carbon metabolism, growth preferences and their mechanisms of adaptation to the environment, as well as their diversity, abundance and activity in the environment. Despite significant strides forward through the cultivation of novel organisms and omics-based approaches, there are still many knowledge gaps on their metabolism and the mechanisms which enable them to adapt to the environment. Ammonia oxidising microorganisms are typically considered metabolically streamlined and highly specialised. Here we review the physiology of ammonia oxidising archaea, with focus on aspects of metabolic versatility and regulation, and discuss these traits in the context of nitrifier ecology.
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Affiliation(s)
- Chloe L Wright
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
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11
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Gulay A, Fournier G, Smets BF, Girguis PR. Proterozoic Acquisition of Archaeal Genes for Extracellular Electron Transfer: A Metabolic Adaptation of Aerobic Ammonia-Oxidizing Bacteria to Oxygen Limitation. Mol Biol Evol 2023; 40:msad161. [PMID: 37440531 PMCID: PMC10415592 DOI: 10.1093/molbev/msad161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/09/2023] [Accepted: 07/06/2023] [Indexed: 07/15/2023] Open
Abstract
Many aerobic microbes can utilize alternative electron acceptors under oxygen-limited conditions. In some cases, this is mediated by extracellular electron transfer (or EET), wherein electrons are transferred to extracellular oxidants such as iron oxide and manganese oxide minerals. Here, we show that an ammonia-oxidizer previously known to be strictly aerobic, Nitrosomonas communis, may have been able to utilize a poised electrode to maintain metabolic activity in anoxic conditions. The presence and activity of multiheme cytochromes in N. communis further suggest a capacity for EET. Molecular clock analysis shows that the ancestors of β-proteobacterial ammonia oxidizers appeared after Earth's atmospheric oxygenation when the oxygen levels were >10-4pO2 (present atmospheric level [PAL]), consistent with aerobic origins. Equally important, phylogenetic reconciliations of gene and species trees show that the multiheme c-type EET proteins in Nitrosomonas and Nitrosospira lineages were likely acquired by gene transfer from γ-proteobacteria when the oxygen levels were between 0.1 and 1 pO2 (PAL). These results suggest that β-proteobacterial EET evolved during the Proterozoic when oxygen limitation was widespread, but oxidized minerals were abundant.
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Affiliation(s)
- Arda Gulay
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Department of Environmental and Resource Engineering, Technical University of Denmark, Lyngby, Denmark
| | - Greg Fournier
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Barth F Smets
- Department of Environmental and Resource Engineering, Technical University of Denmark, Lyngby, Denmark
| | - Peter R Girguis
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
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12
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Li S, Yang S, Wei X, Jiao S, Luo W, Chen W, Wei G. Reduced trace gas oxidizers as a response to organic carbon availability linked to oligotrophs in desert fertile islands. THE ISME JOURNAL 2023; 17:1257-1266. [PMID: 37253970 PMCID: PMC10356767 DOI: 10.1038/s41396-023-01437-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 05/03/2023] [Accepted: 05/19/2023] [Indexed: 06/01/2023]
Abstract
Atmospheric trace gases, such as H2 and CO, are important energy sources for microbial growth and maintenance in various ecosystems, especially in arid deserts with little organic substrate. Nonetheless, the impact of soil organic C availability on microbial trace gas oxidation and the underlying mechanisms are unclear at the community level. This study investigated the energy and life-history strategies of soil microbiomes along an organic C gradient inside and out of Hedysarum scoparium islands dispersed in the Mu Us Desert, China. Metagenomic analysis showed that with increasing organic C availability from bare areas into "fertile islands", the abundance of trace gas oxidizers (TGOs) decreased, but that of trace gas nonoxidizers (TGNOs) increased. The variation in their abundance was more related to labile/soluble organic C levels than to stable/insoluble organic C levels. The consumption rates of H2 and CO confirmed that organic C addition, especially soluble organic C addition, inhibited microbial trace gas oxidation. Moreover, microorganisms with distinct energy-acquiring strategies showed different life-history traits. The TGOs had lower 16 S rRNA operon copy numbers, lower predicted maximum growth rates and higher proportions of labile C degradation genes, implying the prevalence of oligotrophs. In contrast, copiotrophs were prevalent in the TGNOs. These results revealed a mechanism for the microbial community to adapt to the highly heterogeneous distribution of C resources by adjusting the abundances of taxa with distinct energy and life-history strategies, which would further affect trace gas consumption and C turnover in desert ecosystems.
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Affiliation(s)
- Shuyue Li
- State Key Laboratory of Crop Stress Biology in Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Shanshan Yang
- State Key Laboratory of Crop Stress Biology in Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Xiaomeng Wei
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, China
| | - Shuo Jiao
- State Key Laboratory of Crop Stress Biology in Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Wen Luo
- State Key Laboratory of Crop Stress Biology in Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Weimin Chen
- State Key Laboratory of Crop Stress Biology in Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China.
| | - Gehong Wei
- State Key Laboratory of Crop Stress Biology in Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China.
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13
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Liang Y, Plourde A, Bueler SA, Liu J, Brzezinski P, Vahidi S, Rubinstein JL. Structure of mycobacterial respiratory complex I. Proc Natl Acad Sci U S A 2023; 120:e2214949120. [PMID: 36952383 PMCID: PMC10068793 DOI: 10.1073/pnas.2214949120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 02/10/2023] [Indexed: 03/24/2023] Open
Abstract
Oxidative phosphorylation, the combined activity of the electron transport chain (ETC) and adenosine triphosphate synthase, has emerged as a valuable target for the treatment of infection by Mycobacterium tuberculosis and other mycobacteria. The mycobacterial ETC is highly branched with multiple dehydrogenases transferring electrons to a membrane-bound pool of menaquinone and multiple oxidases transferring electrons from the pool. The proton-pumping type I nicotinamide adenine dinucleotide (NADH) dehydrogenase (Complex I) is found in low abundance in the plasma membranes of mycobacteria in typical in vitro culture conditions and is often considered dispensable. We found that growth of Mycobacterium smegmatis in carbon-limited conditions greatly increased the abundance of Complex I and allowed isolation of a rotenone-sensitive preparation of the enzyme. Determination of the structure of the complex by cryoEM revealed the "orphan" two-component response regulator protein MSMEG_2064 as a subunit of the assembly. MSMEG_2064 in the complex occupies a site similar to the proposed redox-sensing subunit NDUFA9 in eukaryotic Complex I. An apparent purine nucleoside triphosphate within the NuoG subunit resembles the GTP-derived molybdenum cofactor in homologous formate dehydrogenase enzymes. The membrane region of the complex binds acyl phosphatidylinositol dimannoside, a characteristic three-tailed lipid from the mycobacterial membrane. The structure also shows menaquinone, which is preferentially used over ubiquinone by gram-positive bacteria, in two different positions along the quinone channel, comparable to ubiquinone in other structures and suggesting a conserved quinone binding mechanism.
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Affiliation(s)
- Yingke Liang
- Molecular Medicine Program, The Hospital for Sick Children, TorontoM5G 0A4, Canada
- Department of Biochemistry, University of Toronto, TorontoM5S 1A8, Canada
| | - Alicia Plourde
- Department of Molecular and Cellular Biology, University of Guelph, TorontoN1G 2W1, Canada
| | - Stephanie A. Bueler
- Molecular Medicine Program, The Hospital for Sick Children, TorontoM5G 0A4, Canada
| | - Jun Liu
- Department of Molecular Genetics, University of Toronto, TorontoM5S 1A8, Canada
| | - Peter Brzezinski
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91Stockholm, Sweden
| | - Siavash Vahidi
- Department of Molecular and Cellular Biology, University of Guelph, TorontoN1G 2W1, Canada
| | - John L. Rubinstein
- Molecular Medicine Program, The Hospital for Sick Children, TorontoM5G 0A4, Canada
- Department of Biochemistry, University of Toronto, TorontoM5S 1A8, Canada
- Department of Medical Biophysics, University of Toronto, TorontoM5G 1L7, Canada
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14
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Ding C, Xu X, Liu Y, Huang X, Xi M, Liu H, Deyett E, Dumont MG, Di H, Hernández M, Xu J, Li Y. Diversity and assembly of active bacteria and their potential function along soil aggregates in a paddy field. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 866:161360. [PMID: 36610629 DOI: 10.1016/j.scitotenv.2022.161360] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 12/23/2022] [Accepted: 12/30/2022] [Indexed: 06/17/2023]
Abstract
Numerous studies have found that soil microbiomes differ at the aggregate level indicating they provide spatially heterogeneous habitats for microbial communities to develop. However, an understanding of the assembly processes and the functional profile of microbes at the aggregate level remain largely rudimentary, particularly for those active members in soil aggregates. In this study, we investigated the diversity, co-occurrence network, assembly process and predictive functional profile of active bacteria in aggregates of different sizes using H218O-based DNA stable isotope probing (SIP) and 16S rRNA gene sequencing. Most of the bacterial reads were active with 91 % of total reads incorporating labelled water during the incubation. The active microbial community belonged mostly of Proteobacteria and Actinobacteria, with a relative abundance of 55.32 % and 28.12 %, respectively. Assembly processes of the active bacteria were more stochastic than total bacteria, while the assembly processes of total bacteria were more influenced by deterministic processes. Furthermore, many functional profiles such as environmental information processing increased in active bacteria (19.39 %) compared to total bacteria (11.22 %). After incubation, the diversity and relative abundance of active bacteria of certain phyla increased, such as Proteobacteria (50.70 % to 59.95 %), Gemmatimonadetes (2.63 % to 4.11 %), and Bacteroidetes (1.50 % to 2.84 %). In small macroaggregates (SMA: 0.25-2 mm), the active bacterial community and its assembly processes differed from that of other soil aggregates (MA: microaggregates, <0.25 mm; LMA: large macroaggregates, 2-4 mm). For functional profiles, the relative abundance of important functions, such as amino acid metabolism, signal transduction and cell motility, increased with incubation days and/or in SMA compared to other aggregates. This study provides robust evidence that the community of active bacteria and its assembly processes in soil aggregates differed from total bacteria, and suggests the importance of dominant active bacteria (such as Proteobacteria) for the predicted functional profiles in the soil ecosystem.
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Affiliation(s)
- Chenxiao Ding
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xinji Xu
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yaowei Liu
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xing Huang
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - MengYuan Xi
- Department of Botany and Plant Sciences, University of California, Riverside 92521, USA
| | - Haiyang Liu
- College of Resources and Environment, Henan Agricultural University, Zhengzhou 450002, China
| | - Elizabeth Deyett
- Department of Botany and Plant Sciences, University of California, Riverside 92521, USA
| | - Marc G Dumont
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Hongjie Di
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Marcela Hernández
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Jianming Xu
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yong Li
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
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15
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Sparks IL, Derbyshire KM, Jacobs WR, Morita YS. Mycobacterium smegmatis: The Vanguard of Mycobacterial Research. J Bacteriol 2023; 205:e0033722. [PMID: 36598232 PMCID: PMC9879119 DOI: 10.1128/jb.00337-22] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The genus Mycobacterium contains several slow-growing human pathogens, including Mycobacterium tuberculosis, Mycobacterium leprae, and Mycobacterium avium. Mycobacterium smegmatis is a nonpathogenic and fast growing species within this genus. In 1990, a mutant of M. smegmatis, designated mc2155, that could be transformed with episomal plasmids was isolated, elevating M. smegmatis to model status as the ideal surrogate for mycobacterial research. Classical bacterial models, such as Escherichia coli, were inadequate for mycobacteria research because they have low genetic conservation, different physiology, and lack the novel envelope structure that distinguishes the Mycobacterium genus. By contrast, M. smegmatis encodes thousands of conserved mycobacterial gene orthologs and has the same cell architecture and physiology. Dissection and characterization of conserved genes, structures, and processes in genetically tractable M. smegmatis mc2155 have since provided previously unattainable insights on these same features in its slow-growing relatives. Notably, tuberculosis (TB) drugs, including the first-line drugs isoniazid and ethambutol, are active against M. smegmatis, but not against E. coli, allowing the identification of their physiological targets. Furthermore, Bedaquiline, the first new TB drug in 40 years, was discovered through an M. smegmatis screen. M. smegmatis has become a model bacterium, not only for M. tuberculosis, but for all other Mycobacterium species and related genera. With a repertoire of bioinformatic and physical resources, including the recently established Mycobacterial Systems Resource, M. smegmatis will continue to accelerate mycobacterial research and advance the field of microbiology.
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Affiliation(s)
- Ian L. Sparks
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
| | - Keith M. Derbyshire
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, University at Albany, Albany, New York, USA
| | - William R. Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Yasu S. Morita
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, USA
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16
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Chauhan P, Datta I, Dhiman A, Shankar U, Kumar A, Vashist A, Sharma TK, Tyagi JS. DNA Aptamer Targets Mycobacterium tuberculosis DevR/DosR Response Regulator Function by Inhibiting Its Dimerization and DNA Binding Activity. ACS Infect Dis 2022; 8:2540-2551. [PMID: 36332135 DOI: 10.1021/acsinfecdis.2c00414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Tuberculosis is recognized as one of the major public health threats worldwide. The DevR-DevS (DosR/DosS) two-component system is considered a novel drug target in Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis, owing to its central role in bacterial adaptation and long-term persistence. An increase in DevR levels and the decreased permeability of the mycobacterial cell wall during hypoxia-associated dormancy pose formidable challenges to the development of anti-DevR compounds. Using an in vitro evolution approach of Systematic Evolution of Ligands by EXponential enrichment (SELEX), we developed a panel of single-stranded DNA aptamers that interacted with Mtb DevR protein in solid-phase binding assays. The best-performing aptamer, APT-6, forms a G-quadruplex structure and inhibits DevR-dependent transcription in Mycobacterium smegmatis. Mechanistic studies indicate that APT-6 functions by inhibiting the dimerization and DNA binding activity of DevR protein. In silico studies reveal that APT-6 interacts majorly with C-terminal domain residues that participate in DNA binding and formation of active dimer species of DevR. To the best of our knowledge, this is the first report of a DNA aptamer that inhibits the function of a cytosolic bacterial response regulator. By inhibiting the dimerization of DevR, APT-6 targets an essential step in the DevR activation mechanism, and therefore, it has the potential to universally block the expression of DevR-regulated genes for intercepting dormancy pathways in mycobacteria. These findings also pave the way for exploring aptamer-based approaches to design and develop potent inhibitors against intracellular proteins of various bacterial pathogens of global concern.
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Affiliation(s)
- Priyanka Chauhan
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Ishara Datta
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Abhijeet Dhiman
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Uma Shankar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore453552, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore453552, India
| | - Atul Vashist
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Tarun Kumar Sharma
- Translational Health Science and Technology Institute (THSTI), Faridabad, Haryana121001, India
| | - Jaya Sivaswami Tyagi
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
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17
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Huang H, Lin L, Bu F, Su Y, Zheng X, Chen Y. Reductive Stress Boosts the Horizontal Transfer of Plasmid-Borne Antibiotic Resistance Genes: The Neglected Side of the Intracellular Redox Spectrum. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15594-15606. [PMID: 36322896 DOI: 10.1021/acs.est.2c04276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The dissemination of plasmid-borne antibiotic resistance genes (ARGs) among bacteria is becoming a global challenge to the "One Health" concept. During conjugation, the donor/recipient usually encounter diverse stresses induced by the surrounding environment. Previous studies mainly focused on the effects of oxidative stress on plasmid conjugation, but ignored the potential contribution of reductive stress (RS), the other side of the intracellular redox spectrum. Herein, we demonstrated for the first time that RS induced by dithiothreitol could significantly boost the horizontal transfer of plasmid RP4 from Escherichia coli K12 to different recipients (E. coli HB101, Salmonella Typhimurium, and Pseudomonas putida KT2440). Phenotypic and genotypic tests confirmed that RS upregulated genes encoding the transfer apparatus of plasmid RP4, which was attributed to the promoted consumption of intracellular glutamine in the donor rather than the widely reported SOS response. Moreover, RS was verified to benefit ATP supply by activating glycolysis (e.g., GAPDH) and the respiratory chain (e.g., appBC), triggering the deficiency of intracellular free Mg2+ by promoting its binding, and reducing membrane permeability by stimulating cardiolipin biosynthesis, all of which were beneficial to the functioning of transfer apparatus. Overall, our findings uncovered the neglected risks of RS in ARG spreading and updated the regulatory mechanism of plasmid conjugation.
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Affiliation(s)
- Haining Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Lin Lin
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Fan Bu
- Shanghai Electric Environmental Protection Group, Shanghai Electric Group Co. Ltd, Shanghai 200092, China
| | - Yinglong Su
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200092, China
| | - Xiong Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
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18
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Zabermawi NMO, Alyhaiby AH, El-Bestawy EA. Microbiological analysis and bioremediation bioassay for characterization of industrial effluent. Sci Rep 2022; 12:18889. [PMID: 36344545 PMCID: PMC9640613 DOI: 10.1038/s41598-022-23480-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 11/01/2022] [Indexed: 11/09/2022] Open
Abstract
This study aims to investigate bacteria for biodegradation of oil pollutants from oily industrial wastewater to be used as bioremediation tools and to determine the characterization of bioremediation bioassays. A screening bioassay was carried out using six exogenous environmental bacterial strains to degrade oily pollution, which indicated promising clearance of the oily wastewater. Two strains, namely Enterobacter cloacae 279-56 (R4) and Pseudomonas otitis MCC10330 (R19), could successfully eliminate oil content and reasonable removal of the organic load. Results showed that the two promising bacterial candidates (R4 and R19) were selected according to the preliminary screening of the six tested bacteria considered the most efficient for all the tested parameters. The highest Removal Efficiency (Removal Efficiency resulted in Residual levels of total dissolved solids (TDS), biochemical oxygen demand, chemical oxygen demand, and Oil content in the treated oily wastewater effluents are 1940, 171, 131, and 84 mg/l respectively where these results are not within safe discharge limits, except for TDS. Hence, the bioremediation assays were carried out using the mixed culture since it was the most efficient strain for degrading all tested parameters.
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Affiliation(s)
- Nidal Mohammed Omar Zabermawi
- grid.412125.10000 0001 0619 1117Department of Biological Sciences, Microbiology, Faculty of Sciences, King Abdulaziz University, Jeddah, 21589 Saudi Arabia
| | - Amani H. Alyhaiby
- grid.412125.10000 0001 0619 1117Department of Biological Sciences, Microbiology, Faculty of Sciences, King Abdulaziz University, Jeddah, 21589 Saudi Arabia
| | - Ebtesam A. El-Bestawy
- grid.7155.60000 0001 2260 6941Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria University, 163 Horria Ave. El-Shatby, P.O. Box 832, Alexandria, Egypt
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19
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Anand P, Akhter Y. A review on enzyme complexes of electron transport chain from Mycobacterium tuberculosis as promising drug targets. Int J Biol Macromol 2022; 212:474-494. [PMID: 35613677 DOI: 10.1016/j.ijbiomac.2022.05.124] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/05/2022] [Accepted: 05/17/2022] [Indexed: 12/20/2022]
Abstract
Energy metabolism is a universal process occurring in all life forms. In Mycobacterium tuberculosis (Mtb), energy production is carried out in two possible ways, oxidative phosphorylation (OxPhos) and substrate-level phosphorylation. Mtb is an obligate aerobic bacterium, making it dependent on OxPhos for ATP synthesis and growth. Mtb inhabits varied micro-niches during the infection cycle, outside and within the host cells, which alters its primary metabolic pathways during the pathogenesis. In this review, we discuss cellular respiration in the context of the mechanism and structural importance of the proteins and enzyme complexes involved. These protein-protein complexes have been proven to be essential for Mtb virulence as they aid the bacteria's survival during aerobic and hypoxic conditions. ATP synthase, a crucial component of the electron transport chain, has been in the limelight, as a prominent drug target against tuberculosis. Likewise, in this review, we have explored other protein-protein complexes of the OxPhos pathway, their functional essentiality, and their mechanism in Mtb's diverse lifecycle. The review summarises crucial target proteins and reported inhibitors of the electron transport chain pathway of Mtb.
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Affiliation(s)
- Pragya Anand
- Department of Biotechnology, School of Life Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Lucknow, Uttar Pradesh 226025, India
| | - Yusuf Akhter
- Department of Biotechnology, School of Life Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Lucknow, Uttar Pradesh 226025, India.
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20
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Harold LK, Jinich A, Hards K, Cordeiro A, Keighley LM, Cross A, McNeil MB, Rhee K, Cook GM. Deciphering functional redundancy and energetics of malate oxidation in mycobacteria. J Biol Chem 2022; 298:101859. [PMID: 35337802 PMCID: PMC9062433 DOI: 10.1016/j.jbc.2022.101859] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 03/20/2022] [Accepted: 03/21/2022] [Indexed: 02/07/2023] Open
Abstract
Oxidation of malate to oxaloacetate, catalyzed by either malate dehydrogenase (Mdh) or malate quinone oxidoreductase (Mqo), is a critical step of the tricarboxylic acid cycle. Both Mqo and Mdh are found in most bacterial genomes, but the level of functional redundancy between these enzymes remains unclear. A bioinformatic survey revealed that Mqo was not as widespread as Mdh in bacteria but that it was highly conserved in mycobacteria. We therefore used mycobacteria as a model genera to study the functional role(s) of Mqo and its redundancy with Mdh. We deleted mqo from the environmental saprophyte Mycobacterium smegmatis, which lacks Mdh, and found that Mqo was essential for growth on nonfermentable carbon sources. On fermentable carbon sources, the Δmqo mutant exhibited delayed growth and lowered oxygen consumption and secreted malate and fumarate as terminal end products. Furthermore, heterologous expression of Mdh from the pathogenic species Mycobacterium tuberculosis shortened the delayed growth on fermentable carbon sources and restored growth on nonfermentable carbon sources at a reduced growth rate. In M. tuberculosis, CRISPR interference of either mdh or mqo expression resulted in a slower growth rate compared to controls, which was further inhibited when both genes were knocked down simultaneously. These data reveal that exergonic Mqo activity powers mycobacterial growth under nonenergy limiting conditions and that endergonic Mdh activity complements Mqo activity, but at an energetic cost for mycobacterial growth. We propose Mdh is maintained in slow-growing mycobacterial pathogens for use under conditions such as hypoxia that require reductive tricarboxylic acid cycle activity.
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Affiliation(s)
- Liam K Harold
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand.
| | - Adrian Jinich
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Kiel Hards
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Alexandra Cordeiro
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Laura M Keighley
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Alec Cross
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Matthew B McNeil
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Kyu Rhee
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Gregory M Cook
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand.
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21
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Greening C, Grinter R. Microbial oxidation of atmospheric trace gases. Nat Rev Microbiol 2022; 20:513-528. [PMID: 35414013 DOI: 10.1038/s41579-022-00724-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2022] [Indexed: 02/06/2023]
Abstract
The atmosphere has recently been recognized as a major source of energy sustaining life. Diverse aerobic bacteria oxidize the three most abundant reduced trace gases in the atmosphere, namely hydrogen (H2), carbon monoxide (CO) and methane (CH4). This Review describes the taxonomic distribution, physiological role and biochemical basis of microbial oxidation of these atmospheric trace gases, as well as the ecological, environmental, medical and astrobiological importance of this process. Most soil bacteria and some archaea can survive by using atmospheric H2 and CO as alternative energy sources, as illustrated through genetic studies on Mycobacterium cells and Streptomyces spores. Certain specialist bacteria can also grow on air alone, as confirmed by the landmark characterization of Methylocapsa gorgona, which grows by simultaneously consuming atmospheric CH4, H2 and CO. Bacteria use high-affinity lineages of metalloenzymes, namely hydrogenases, CO dehydrogenases and methane monooxygenases, to utilize atmospheric trace gases for aerobic respiration and carbon fixation. More broadly, trace gas oxidizers enhance the biodiversity and resilience of soil and marine ecosystems, drive primary productivity in extreme environments such as Antarctic desert soils and perform critical regulatory services by mitigating anthropogenic emissions of greenhouse gases and toxic pollutants.
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Affiliation(s)
- Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia. .,Securing Antarctica's Environmental Future, Monash University, Clayton, Victoria, Australia. .,Centre to Impact AMR, Monash University, Clayton, Victoria, Australia.
| | - Rhys Grinter
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
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22
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Gupta A, Singh UB, Sahu PK, Paul S, Kumar A, Malviya D, Singh S, Kuppusamy P, Singh P, Paul D, Rai JP, Singh HV, Manna MC, Crusberg TC, Kumar A, Saxena AK. Linking Soil Microbial Diversity to Modern Agriculture Practices: A Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19053141. [PMID: 35270832 DOI: 10.3390/ijerph190531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 03/04/2022] [Accepted: 03/04/2022] [Indexed: 05/28/2023]
Abstract
Agriculture is a multifarious interface between plants and associated microorganisms. In contemporary agriculture, emphasis is being given to environmentally friendly approaches, particularly in developing countries, to enhance sustainability of the system with the least negative effects on produce quality and quantity. Modern agricultural practices such as extensive tillage, the use of harmful agrochemicals, mono-cropping, etc. have been found to influence soil microbial community structure and soil sustainability. On the other hand, the question of feeding the ever-growing global population while ensuring system sustainability largely remains unanswered. Agriculturally important microorganisms are envisaged to play important roles in various measures to raise a healthy and remunerative crop, including integrated nutrient management, as well as disease and pest management to cut down agrochemicals without compromising the agricultural production. These beneficial microorganisms seem to have every potential to provide an alternative opportunity to overcome the ill effects of various components of traditional agriculture being practiced by and large. Despite an increased awareness of the importance of organically produced food, farmers in developing countries still tend to apply inorganic chemical fertilizers and toxic chemical pesticides beyond the recommended doses. Nutrient uptake enhancement, biocontrol of pests and diseases using microbial inoculants may replace/reduce agrochemicals in agricultural production system. The present review aims to examine and discuss the shift in microbial population structure due to current agricultural practices and focuses on the development of a sustainable agricultural system employing the tremendous untapped potential of the microbial world.
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Affiliation(s)
- Amrita Gupta
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India
| | - Udai B Singh
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India
| | - Pramod K Sahu
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India
| | - Surinder Paul
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India
| | - Adarsh Kumar
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India
| | - Deepti Malviya
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India
| | - Shailendra Singh
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India
| | - Pandiyan Kuppusamy
- ICAR-Central Institute for Research on Cotton Technology, Ginning Training Centre, Nagpur 440023, India
| | - Prakash Singh
- Department of Plant Breeding and Genetics, Veer Kunwar Singh College of Agriculture, Bihar Agricultural University, Dumraon 802136, India
| | - Diby Paul
- Pilgram Marpeck School of Science, Technology, Engineering and Mathematics, Truett McConnel University, 100 Alumni Dr., Cleveland, GA 30528, USA
| | - Jai P Rai
- Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Harsh V Singh
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India
| | - Madhab C Manna
- Soil Biology Division, ICAR-Indian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal 462038, India
| | - Theodore C Crusberg
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01605, USA
| | - Arun Kumar
- Department of Agronomy, Bihar Agricultural University, Sabour, Bhagalpur 813210, India
| | - Anil K Saxena
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India
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23
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Gupta A, Singh UB, Sahu PK, Paul S, Kumar A, Malviya D, Singh S, Kuppusamy P, Singh P, Paul D, Rai JP, Singh HV, Manna MC, Crusberg TC, Kumar A, Saxena AK. Linking Soil Microbial Diversity to Modern Agriculture Practices: A Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:3141. [PMID: 35270832 PMCID: PMC8910389 DOI: 10.3390/ijerph19053141] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 03/04/2022] [Accepted: 03/04/2022] [Indexed: 12/01/2022]
Abstract
Agriculture is a multifarious interface between plants and associated microorganisms. In contemporary agriculture, emphasis is being given to environmentally friendly approaches, particularly in developing countries, to enhance sustainability of the system with the least negative effects on produce quality and quantity. Modern agricultural practices such as extensive tillage, the use of harmful agrochemicals, mono-cropping, etc. have been found to influence soil microbial community structure and soil sustainability. On the other hand, the question of feeding the ever-growing global population while ensuring system sustainability largely remains unanswered. Agriculturally important microorganisms are envisaged to play important roles in various measures to raise a healthy and remunerative crop, including integrated nutrient management, as well as disease and pest management to cut down agrochemicals without compromising the agricultural production. These beneficial microorganisms seem to have every potential to provide an alternative opportunity to overcome the ill effects of various components of traditional agriculture being practiced by and large. Despite an increased awareness of the importance of organically produced food, farmers in developing countries still tend to apply inorganic chemical fertilizers and toxic chemical pesticides beyond the recommended doses. Nutrient uptake enhancement, biocontrol of pests and diseases using microbial inoculants may replace/reduce agrochemicals in agricultural production system. The present review aims to examine and discuss the shift in microbial population structure due to current agricultural practices and focuses on the development of a sustainable agricultural system employing the tremendous untapped potential of the microbial world.
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Affiliation(s)
- Amrita Gupta
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India; (A.G.); (U.B.S.); (P.K.S.); (S.P.); (A.K.); (D.M.); (S.S.); (H.V.S.); (A.K.S.)
| | - Udai B. Singh
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India; (A.G.); (U.B.S.); (P.K.S.); (S.P.); (A.K.); (D.M.); (S.S.); (H.V.S.); (A.K.S.)
| | - Pramod K. Sahu
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India; (A.G.); (U.B.S.); (P.K.S.); (S.P.); (A.K.); (D.M.); (S.S.); (H.V.S.); (A.K.S.)
| | - Surinder Paul
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India; (A.G.); (U.B.S.); (P.K.S.); (S.P.); (A.K.); (D.M.); (S.S.); (H.V.S.); (A.K.S.)
| | - Adarsh Kumar
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India; (A.G.); (U.B.S.); (P.K.S.); (S.P.); (A.K.); (D.M.); (S.S.); (H.V.S.); (A.K.S.)
| | - Deepti Malviya
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India; (A.G.); (U.B.S.); (P.K.S.); (S.P.); (A.K.); (D.M.); (S.S.); (H.V.S.); (A.K.S.)
| | - Shailendra Singh
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India; (A.G.); (U.B.S.); (P.K.S.); (S.P.); (A.K.); (D.M.); (S.S.); (H.V.S.); (A.K.S.)
| | - Pandiyan Kuppusamy
- ICAR-Central Institute for Research on Cotton Technology, Ginning Training Centre, Nagpur 440023, India;
| | - Prakash Singh
- Department of Plant Breeding and Genetics, Veer Kunwar Singh College of Agriculture, Bihar Agricultural University, Dumraon 802136, India;
| | - Diby Paul
- Pilgram Marpeck School of Science, Technology, Engineering and Mathematics, Truett McConnel University, 100 Alumni Dr., Cleveland, GA 30528, USA;
| | - Jai P. Rai
- Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Harsh V. Singh
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India; (A.G.); (U.B.S.); (P.K.S.); (S.P.); (A.K.); (D.M.); (S.S.); (H.V.S.); (A.K.S.)
| | - Madhab C. Manna
- Soil Biology Division, ICAR-Indian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal 462038, India;
| | - Theodore C. Crusberg
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01605, USA;
| | - Arun Kumar
- Department of Agronomy, Bihar Agricultural University, Sabour, Bhagalpur 813210, India;
| | - Anil K. Saxena
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan 275103, India; (A.G.); (U.B.S.); (P.K.S.); (S.P.); (A.K.); (D.M.); (S.S.); (H.V.S.); (A.K.S.)
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24
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Bay SK, Waite DW, Dong X, Gillor O, Chown SL, Hugenholtz P, Greening C. Chemosynthetic and photosynthetic bacteria contribute differentially to primary production across a steep desert aridity gradient. THE ISME JOURNAL 2021; 15:3339-3356. [PMID: 34035443 PMCID: PMC8528921 DOI: 10.1038/s41396-021-01001-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/16/2021] [Accepted: 04/28/2021] [Indexed: 02/04/2023]
Abstract
Desert soils harbour diverse communities of aerobic bacteria despite lacking substantial organic carbon inputs from vegetation. A major question is therefore how these communities maintain their biodiversity and biomass in these resource-limiting ecosystems. Here, we investigated desert topsoils and biological soil crusts collected along an aridity gradient traversing four climatic regions (sub-humid, semi-arid, arid, and hyper-arid). Metagenomic analysis indicated these communities vary in their capacity to use sunlight, organic compounds, and inorganic compounds as energy sources. Thermoleophilia, Actinobacteria, and Acidimicrobiia were the most abundant and prevalent bacterial classes across the aridity gradient in both topsoils and biocrusts. Contrary to the classical view that these taxa are obligate organoheterotrophs, genome-resolved analysis suggested they are metabolically flexible, with the capacity to also use atmospheric H2 to support aerobic respiration and often carbon fixation. In contrast, Cyanobacteria were patchily distributed and only abundant in certain biocrusts. Activity measurements profiled how aerobic H2 oxidation, chemosynthetic CO2 fixation, and photosynthesis varied with aridity. Cell-specific rates of atmospheric H2 consumption increased 143-fold along the aridity gradient, correlating with increased abundance of high-affinity hydrogenases. Photosynthetic and chemosynthetic primary production co-occurred throughout the gradient, with photosynthesis dominant in biocrusts and chemosynthesis dominant in arid and hyper-arid soils. Altogether, these findings suggest that the major bacterial lineages inhabiting hot deserts use different strategies for energy and carbon acquisition depending on resource availability. Moreover, they highlight the previously overlooked roles of Actinobacteriota as abundant primary producers and trace gases as critical energy sources supporting productivity and resilience of desert ecosystems.
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Affiliation(s)
- Sean K Bay
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.
| | - David W Waite
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD, Australia
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Xiyang Dong
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, China
| | - Osnat Gillor
- Zuckerberg Institute for Water Research, Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Sde Boker, Israel
| | - Steven L Chown
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Philip Hugenholtz
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD, Australia
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.
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25
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Giddey AD, Ganief TA, Ganief N, Koch A, Warner DF, Soares NC, Blackburn JM. Cell Wall Proteomics Reveal Phenotypic Adaption of Drug-Resistant Mycobacterium smegmatis to Subinhibitory Rifampicin Exposure. Front Med (Lausanne) 2021; 8:723667. [PMID: 34676224 PMCID: PMC8525676 DOI: 10.3389/fmed.2021.723667] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/24/2021] [Indexed: 01/01/2023] Open
Abstract
Despite the availability of effective drug treatment, Mycobacterium tuberculosis (Mtb), the causative agent of TB disease, kills ~1. 5 million people annually, and the rising prevalence of drug resistance increasingly threatens to worsen this plight. We previously showed that sublethal exposure to the frontline anti-TB drug, rifampicin, resulted in substantial adaptive remodeling of the proteome of the model organism, Mycobacterium smegmatis, in the drug-sensitive mc2155 strain [wild type (WT)]. In this study, we investigate whether these responses are conserved in an engineered, isogenic mutant harboring the clinically relevant S531L rifampicin resistance-conferring mutation (SL) and distinguish the responses that are specific to RNA polymerase β subunit- (RpoB-) binding activity of rifampicin from those that are dependent on the presence of rifampicin alone. We verified the drug resistance status of this strain and observed no phenotypic indications of rifampicin-induced stress upon treatment with the same concentration as used in WT (2.5 μg/ml). Thereafter, we used a cell wall-enrichment strategy to focus attention on the cell wall proteome and observed 253 proteins to be dysregulated in SL bacteria in comparison with 716 proteins in WT. We observed that decreased abundance of ATP-binding cassette (ABC) transporters and increased abundance of ribosomal machinery were conserved in the SL strain, whereas the upregulation of transcriptional machinery and the downregulation of numerous two-component systems were not. We conclude that the drug-resistant M. smegmatis strain displays some of the same proteomic responses observed in WT and suggest that this evidence supports the hypothesis that rifampicin exercises effects beyond RpoB-interaction alone and that mycobacteria recognise rifampicin as a signaling molecule in an RpoB-independent manner at sublethal doses. Taken together, our data indicates mixed RpoB-independent and RpoB-dependent proteomic remodeling in WT mycobacteria, with evidence for RpoB-independent ABC transporter downregulation, but drug activity-based transcriptional upregulation and two-component system downregulation.
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Affiliation(s)
- Alexander D Giddey
- Division of Chemical and Systems Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Tariq A Ganief
- Division of Chemical and Systems Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Naadir Ganief
- Division of Chemical and Systems Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Anastasia Koch
- South African Medical Research Council/National Health Laboratory Service/University of Cape Town Molecular Mycobacteriology Research Unit, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Digby F Warner
- South African Medical Research Council/National Health Laboratory Service/University of Cape Town Molecular Mycobacteriology Research Unit, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Nelson C Soares
- College of Pharmacy, University of Sharjah, Sharjah, United Arab Emirates.,Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Jonathan M Blackburn
- Division of Chemical and Systems Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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26
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Greening C, Islam ZF, Bay SK. Hydrogen is a major lifeline for aerobic bacteria. Trends Microbiol 2021; 30:330-337. [PMID: 34462186 DOI: 10.1016/j.tim.2021.08.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/06/2021] [Accepted: 08/09/2021] [Indexed: 12/31/2022]
Abstract
Molecular hydrogen (H2) is available in trace amounts in most ecosystems through atmospheric, biological, geochemical, and anthropogenic sources. Aerobic bacteria use this energy-dense gas, including at atmospheric concentrations, to support respiration and carbon fixation. While it was thought that aerobic H2 consumers are rare community members, here we summarize evidence suggesting that they are dominant throughout soils and other aerated ecosystems. Bacterial cultures from at least eight major phyla can consume atmospheric H2. At the ecosystem scale, H2 consumers are abundant, diverse, and active across diverse soils and are key primary producers in extreme environments such as hyper-arid deserts. On this basis, we propose that H2 is a universally available energy source for the survival of aerobic bacteria.
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Affiliation(s)
- Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Securing Antarctica's Environmental Future, Monash University, Clayton, VIC 3800, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia.
| | - Zahra F Islam
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; STEM College, RMIT University, Bundoora, VIC 3083, Australia
| | - Sean K Bay
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Securing Antarctica's Environmental Future, Monash University, Clayton, VIC 3800, Australia; School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
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27
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Kunota TTR, Rahman MA, Truebody BE, Mackenzie JS, Saini V, Lamprecht DA, Adamson JH, Sevalkar RR, Lancaster JR, Berney M, Glasgow JN, Steyn AJC. Mycobacterium tuberculosis H 2S Functions as a Sink to Modulate Central Metabolism, Bioenergetics, and Drug Susceptibility. Antioxidants (Basel) 2021; 10:1285. [PMID: 34439535 PMCID: PMC8389258 DOI: 10.3390/antiox10081285] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/04/2021] [Accepted: 08/07/2021] [Indexed: 02/03/2023] Open
Abstract
H2S is a potent gasotransmitter in eukaryotes and bacteria. Host-derived H2S has been shown to profoundly alter M. tuberculosis (Mtb) energy metabolism and growth. However, compelling evidence for endogenous production of H2S and its role in Mtb physiology is lacking. We show that multidrug-resistant and drug-susceptible clinical Mtb strains produce H2S, whereas H2S production in non-pathogenic M. smegmatis is barely detectable. We identified Rv3684 (Cds1) as an H2S-producing enzyme in Mtb and show that cds1 disruption reduces, but does not eliminate, H2S production, suggesting the involvement of multiple genes in H2S production. We identified endogenous H2S to be an effector molecule that maintains bioenergetic homeostasis by stimulating respiration primarily via cytochrome bd. Importantly, H2S plays a key role in central metabolism by modulating the balance between oxidative phosphorylation and glycolysis, and it functions as a sink to recycle sulfur atoms back to cysteine to maintain sulfur homeostasis. Lastly, Mtb-generated H2S regulates redox homeostasis and susceptibility to anti-TB drugs clofazimine and rifampicin. These findings reveal previously unknown facets of Mtb physiology and have implications for routine laboratory culturing, understanding drug susceptibility, and improved diagnostics.
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Affiliation(s)
- Tafara T. R. Kunota
- Africa Health Research Institute, University of KwaZulu Natal, Durban 4001, South Africa; (T.T.R.K.); (M.A.R.); (B.E.T.); (J.S.M.); (D.A.L.); (J.H.A.)
| | - Md. Aejazur Rahman
- Africa Health Research Institute, University of KwaZulu Natal, Durban 4001, South Africa; (T.T.R.K.); (M.A.R.); (B.E.T.); (J.S.M.); (D.A.L.); (J.H.A.)
| | - Barry E. Truebody
- Africa Health Research Institute, University of KwaZulu Natal, Durban 4001, South Africa; (T.T.R.K.); (M.A.R.); (B.E.T.); (J.S.M.); (D.A.L.); (J.H.A.)
| | - Jared S. Mackenzie
- Africa Health Research Institute, University of KwaZulu Natal, Durban 4001, South Africa; (T.T.R.K.); (M.A.R.); (B.E.T.); (J.S.M.); (D.A.L.); (J.H.A.)
| | - Vikram Saini
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi 110029, India;
| | - Dirk A. Lamprecht
- Africa Health Research Institute, University of KwaZulu Natal, Durban 4001, South Africa; (T.T.R.K.); (M.A.R.); (B.E.T.); (J.S.M.); (D.A.L.); (J.H.A.)
| | - John H. Adamson
- Africa Health Research Institute, University of KwaZulu Natal, Durban 4001, South Africa; (T.T.R.K.); (M.A.R.); (B.E.T.); (J.S.M.); (D.A.L.); (J.H.A.)
| | - Ritesh R. Sevalkar
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (R.R.S.); (J.N.G.)
| | - Jack R. Lancaster
- Department of Pharmacology and Chemical Biology, Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA;
| | - Michael Berney
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY 10462, USA;
| | - Joel N. Glasgow
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (R.R.S.); (J.N.G.)
| | - Adrie J. C. Steyn
- Africa Health Research Institute, University of KwaZulu Natal, Durban 4001, South Africa; (T.T.R.K.); (M.A.R.); (B.E.T.); (J.S.M.); (D.A.L.); (J.H.A.)
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (R.R.S.); (J.N.G.)
- Centers for AIDS Research and Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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28
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Coskun ÖK, Vuillemin A, Schubotz F, Klein F, Sichel SE, Eisenreich W, Orsi WD. Quantifying the effects of hydrogen on carbon assimilation in a seafloor microbial community associated with ultramafic rocks. ISME JOURNAL 2021; 16:257-271. [PMID: 34312482 PMCID: PMC8692406 DOI: 10.1038/s41396-021-01066-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 07/05/2021] [Accepted: 07/09/2021] [Indexed: 11/09/2022]
Abstract
Thermodynamic models predict that H2 is energetically favorable for seafloor microbial life, but how H2 affects anabolic processes in seafloor-associated communities is poorly understood. Here, we used quantitative 13C DNA stable isotope probing (qSIP) to quantify the effect of H2 on carbon assimilation by microbial taxa synthesizing 13C-labeled DNA that are associated with partially serpentinized peridotite rocks from the equatorial Mid-Atlantic Ridge. The rock-hosted seafloor community was an order of magnitude more diverse compared to the seawater community directly above the rocks. With added H2, peridotite-associated taxa increased assimilation of 13C-bicarbonate and 13C-acetate into 16S rRNA genes of operational taxonomic units by 146% (±29%) and 55% (±34%), respectively, which correlated with enrichment of H2-oxidizing NiFe-hydrogenases encoded in peridotite-associated metagenomes. The effect of H2 on anabolism was phylogenetically organized, with taxa affiliated with Atribacteria, Nitrospira, and Thaumarchaeota exhibiting the most significant increases in 13C-substrate assimilation in the presence of H2. In SIP incubations with added H2, an order of magnitude higher number of peridotite rock-associated taxa assimilated 13C-bicarbonate, 13C-acetate, and 13C-formate compared to taxa that were not associated with peridotites. Collectively, these findings indicate that the unique geochemical nature of the peridotite-hosted ecosystem has selected for H2-metabolizing, rock-associated taxa that can increase anabolism under high H2 concentrations. Because ultramafic rocks are widespread in slow-, and ultraslow-spreading oceanic lithosphere, continental margins, and subduction zones where H2 is formed in copious amounts, the link between H2 and carbon assimilation demonstrated here may be widespread within these geological settings.
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Affiliation(s)
- Ömer K Coskun
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany
| | - Aurèle Vuillemin
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany.,GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
| | - Florence Schubotz
- MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Frieder Klein
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Susanna E Sichel
- Departamento de Geologia e Geofísica/LAGEMAR-Universidade Federal Fluminense-Brazil, Niterói, RJ, Brazil
| | - Wolfgang Eisenreich
- Department of Chemistry, Bavarian NMR Center-Structural Membrane Biochemistry, Technische Universität München, Garching, Germany
| | - William D Orsi
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany. .,GeoBio-CenterLMU, Ludwig-Maximilians-Universität München, Munich, Germany.
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Köstlbacher S, Collingro A, Halter T, Schulz F, Jungbluth SP, Horn M. Pangenomics reveals alternative environmental lifestyles among chlamydiae. Nat Commun 2021; 12:4021. [PMID: 34188040 PMCID: PMC8242063 DOI: 10.1038/s41467-021-24294-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 06/10/2021] [Indexed: 02/07/2023] Open
Abstract
Chlamydiae are highly successful strictly intracellular bacteria associated with diverse eukaryotic hosts. Here we analyzed metagenome-assembled genomes of the "Genomes from Earth's Microbiomes" initiative from diverse environmental samples, which almost double the known phylogenetic diversity of the phylum and facilitate a highly resolved view at the chlamydial pangenome. Chlamydiae are defined by a relatively large core genome indicative of an intracellular lifestyle, and a highly dynamic accessory genome of environmental lineages. We observe chlamydial lineages that encode enzymes of the reductive tricarboxylic acid cycle and for light-driven ATP synthesis. We show a widespread potential for anaerobic energy generation through pyruvate fermentation or the arginine deiminase pathway, and we add lineages capable of molecular hydrogen production. Genome-informed analysis of environmental distribution revealed lineage-specific niches and a high abundance of chlamydiae in some habitats. Together, our data provide an extended perspective of the variability of chlamydial biology and the ecology of this phylum of intracellular microbes.
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Affiliation(s)
- Stephan Köstlbacher
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Astrid Collingro
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Tamara Halter
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | | | | | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria.
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Han SR, Kim B, Jang JH, Park H, Oh TJ. Complete genome sequence of Arthrobacter sp. PAMC25564 and its comparative genome analysis for elucidating the role of CAZymes in cold adaptation. BMC Genomics 2021; 22:403. [PMID: 34078272 PMCID: PMC8171050 DOI: 10.1186/s12864-021-07734-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 05/07/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Arthrobacter group is a known set of bacteria from cold regions, the species of which are highly likely to play diverse roles at low temperatures. However, their survival mechanisms in cold regions such as Antarctica are not yet fully understood. In this study, we compared the genomes of 16 strains within the Arthrobacter group, including strain PAMC25564, to identify genomic features that help it to survive in the cold environment. RESULTS Using 16 S rRNA sequence analysis, we found and identified a species of Arthrobacter isolated from cryoconite. We designated it as strain PAMC25564 and elucidated its complete genome sequence. The genome of PAMC25564 is composed of a circular chromosome of 4,170,970 bp with a GC content of 66.74 % and is predicted to include 3,829 genes of which 3,613 are protein coding, 147 are pseudogenes, 15 are rRNA coding, and 51 are tRNA coding. In addition, we provide insight into the redundancy of the genes using comparative genomics and suggest that PAMC25564 has glycogen and trehalose metabolism pathways (biosynthesis and degradation) associated with carbohydrate active enzyme (CAZymes). We also explain how the PAMC26654 produces energy in an extreme environment, wherein it utilizes polysaccharide or carbohydrate degradation as a source of energy. The genetic pattern analysis of CAZymes in cold-adapted bacteria can help to determine how they adapt and survive in such environments. CONCLUSIONS We have characterized the complete Arthrobacter sp. PAMC25564 genome and used comparative analysis to provide insight into the redundancy of its CAZymes for potential cold adaptation. This provides a foundation to understanding how the Arthrobacter strain produces energy in an extreme environment, which is by way of CAZymes, consistent with reports on the use of these specialized enzymes in cold environments. Knowledge of glycogen metabolism and cold adaptation mechanisms in Arthrobacter species may promote in-depth research and subsequent application in low-temperature biotechnology.
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Affiliation(s)
- So-Ra Han
- Department of Life Science and Biochemical Engineering, Graduate School, SunMoon University, 70 Sunmoon-ro 221, Tangjeong-myeon, 31460, Asan-si, Chungnam, Republic of Korea
| | - Byeollee Kim
- Department of Life Science and Biochemical Engineering, Graduate School, SunMoon University, 70 Sunmoon-ro 221, Tangjeong-myeon, 31460, Asan-si, Chungnam, Republic of Korea
| | - Jong Hwa Jang
- Department of Dental Hygiene, College of Health Science, Dankook University, 119 Dandae-ro, Dongnam-gu, 31116, Cheonan-si, Chungnam, Republic of Korea
| | - Hyun Park
- Division of Biotechnology, College of Life Science and Biotechnology, Korea University, 02841, Seoul, Republic of Korea.
| | - Tae-Jin Oh
- Department of Life Science and Biochemical Engineering, Graduate School, SunMoon University, 70 Sunmoon-ro 221, Tangjeong-myeon, 31460, Asan-si, Chungnam, Republic of Korea. .,Genome-based BioIT Convergence Institute, 70 Sunmoon-ro 221, Tangjeong-myeon, 31460, Asan-si, Chungnam, Republic of Korea. .,Department of Pharmaceutical Engineering and Biotechnology, SunMoon University, 70 Sunmoon-ro 221, Tangjeong-myeon, 31460, Asan-si, Chungnam, Republic of Korea.
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Garcia SL, Mehrshad M, Buck M, Tsuji JM, Neufeld JD, McMahon KD, Bertilsson S, Greening C, Peura S. Freshwater Chlorobia Exhibit Metabolic Specialization among Cosmopolitan and Endemic Populations. mSystems 2021; 6:e01196-20. [PMID: 33975970 PMCID: PMC8125076 DOI: 10.1128/msystems.01196-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 04/09/2021] [Indexed: 01/15/2023] Open
Abstract
Photosynthetic bacteria from the class Chlorobia (formerly phylum Chlorobi) sustain carbon fixation in anoxic water columns. They harvest light at extremely low intensities and use various inorganic electron donors to fix carbon dioxide into biomass. Until now, most information on the functional ecology and local adaptations of Chlorobia members came from isolates and merely 26 sequenced genomes that may not adequately represent natural populations. To address these limitations, we analyzed global metagenomes to profile planktonic Chlorobia cells from the oxyclines of 42 freshwater bodies, spanning subarctic to tropical regions and encompassing all four seasons. We assembled and compiled over 500 genomes, including metagenome-assembled genomes (MAGs), single-amplified genomes (SAGs), and reference genomes from cultures, clustering them into 71 metagenomic operational taxonomic units (mOTUs or "species"). Of the 71 mOTUs, 57 were classified within the genus Chlorobium, and these mOTUs represented up to ∼60% of the microbial communities in the sampled anoxic waters. Several Chlorobium-associated mOTUs were globally distributed, whereas others were endemic to individual lakes. Although most clades encoded the ability to oxidize hydrogen, many lacked genes for the oxidation of specific sulfur and iron substrates. Surprisingly, one globally distributed Scandinavian clade encoded the ability to oxidize hydrogen, sulfur, and iron, suggesting that metabolic versatility facilitated such widespread colonization. Overall, these findings provide new insight into the biogeography of the Chlorobia and the metabolic traits that facilitate niche specialization within lake ecosystems.IMPORTANCE The reconstruction of genomes from metagenomes has helped explore the ecology and evolution of environmental microbiota. We applied this approach to 274 metagenomes collected from diverse freshwater habitats that spanned oxic and anoxic zones, sampling seasons, and latitudes. We demonstrate widespread and abundant distributions of planktonic Chlorobia-associated bacteria in hypolimnetic waters of stratified freshwater ecosystems and show they vary in their capacities to use different electron donors. Having photoautotrophic potential, these Chlorobia members could serve as carbon sources that support metalimnetic and hypolimnetic food webs.
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Affiliation(s)
- Sarahi L Garcia
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Ecology, Environment, and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Maliheh Mehrshad
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
| | - Moritz Buck
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
| | - Jackson M Tsuji
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Josh D Neufeld
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Katherine D McMahon
- Department of Civil and Environmental Engineering, University of Wisconsin, Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin, Madison, Madison, Wisconsin, USA
| | - Stefan Bertilsson
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Sari Peura
- Department of Forest Mycology and Plant Pathology, Science for Life Laboratory, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
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Abstract
Carbon monoxide has an infamous reputation as a toxic gas, and it has been suggested that it has potential as an antibacterial agent. Despite this, how bacteria resist its toxic effects is not well understood. Carbon monoxide (CO) gas is infamous for its acute toxicity. This toxicity predominantly stems from its tendency to form carbonyl complexes with transition metals, thus inhibiting the heme-prosthetic groups of proteins, including respiratory terminal oxidases. While CO has been proposed as an antibacterial agent, the evidence supporting its toxicity toward bacteria is equivocal, and its cellular targets remain poorly defined. In this work, we investigate the physiological response of mycobacteria to CO. We show that Mycobacterium smegmatis is highly resistant to the toxic effects of CO, exhibiting only minor inhibition of growth when cultured in its presence. We profiled the proteome of M. smegmatis during growth in CO, identifying strong induction of cytochrome bd oxidase and members of the dos regulon, but relatively few other changes. We show that the activity of cytochrome bd oxidase is resistant to CO, whereas cytochrome bcc-aa3 oxidase is strongly inhibited by this gas. Consistent with these findings, growth analysis shows that M. smegmatis lacking cytochrome bd oxidase displays a significant growth defect in the presence of CO, while induction of the dos regulon appears to be unimportant for adaptation to CO. Altogether, our findings indicate that M. smegmatis has considerable resistance to CO and benefits from respiratory flexibility to withstand its inhibitory effects. IMPORTANCE Carbon monoxide has an infamous reputation as a toxic gas, and it has been suggested that it has potential as an antibacterial agent. Despite this, how bacteria resist its toxic effects is not well understood. In this study, we investigated how CO influences growth, proteome, and aerobic respiration of wild-type and mutant strains of Mycobacterium smegmatis. We show that this bacterium produces the CO-resistant cytochrome bd oxidase to tolerate poisoning of its CO-sensitive complex IV homolog. Further, we show that aside from this remodeling of its respiratory chain, M. smegmatis makes few other functional changes to its proteome, suggesting it has a high level of inherent resistance to CO.
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Yang Y, Herbold CW, Jung MY, Qin W, Cai M, Du H, Lin JG, Li X, Li M, Gu JD. Survival strategies of ammonia-oxidizing archaea (AOA) in a full-scale WWTP treating mixed landfill leachate containing copper ions and operating at low-intensity of aeration. WATER RESEARCH 2021; 191:116798. [PMID: 33444853 DOI: 10.1016/j.watres.2020.116798] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/22/2020] [Accepted: 12/28/2020] [Indexed: 05/04/2023]
Abstract
Recent studies indicate that ammonia-oxidizing archaea (AOA) may play an important role in nitrogen removal by wastewater treatment plants (WWTPs). However, our knowledge of the mechanisms employed by AOA for growth and survival in full-scale WWTPs is still limited. Here, metagenomic and metatranscriptomic analyses combined with a laboratory cultivation experiment revealed that three active AOAs (WS9, WS192, and WS208) belonging to family Nitrososphaeraceae were active in the deep oxidation ditch (DOD) of a full-scale WWTP treating landfill leachate, which is configured with three continuous aerobic-anoxic (OA) modules with low-intensity aeration (≤ 1.5 mg/L). AOA coexisted with AOB and complete ammonia oxidizers (Comammox), while the ammonia-oxidizing microbial (AOM) community was unexpectedly dominated by the novel AOA strain WS9. The low aeration, long retention time, and relatively high inputs of ammonium and copper might be responsible for the survival of AOA over AOB and Comammox, while the dominance of WS9, specifically may be enhanced by substrate preference and uniquely encoded retention strategies. The urease-negative WS9 is specifically adapted for ammonia acquisition as evidenced by the high expression of an ammonium transporter, whereas two metabolically versatile urease-positive AOA strains (WS192 and WS208) can likely supplement ammonia needs with urea. This study provides important information for the survival and application of the eutrophic Nitrososphaeraceae AOA and advances our understanding of archaea-dominated ammonia oxidation in a full-scale wastewater treatment system.
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Affiliation(s)
- Yuchun Yang
- State Key Laboratory of Biocontrol, School of Ecology, Sun Yat-sen University, Guangzhou 510275, China
| | - Craig W Herbold
- University of Vienna, Center for Microbiology and Environmental Systems Science, Division of Microbial Ecology, Althanstrasse 14, 1090 Vienna, Austria
| | - Man-Young Jung
- Division of Biology Education, Department of Science Education, Jeju National University, 102 Jejudaehak-ro, Jeju 63243, South Korea; Interdisciplinary Graduate Programme in Advance Convergence Technology and Science, Faculty of Science Education, Jeju National University, Jeju 6324, South Korea
| | - Wei Qin
- School of Oceanography, University of Washington, Seattle, Washington, United States; Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
| | - Mingwei Cai
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Huan Du
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Jih-Gaw Lin
- Institute of Environmental Engineering, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan
| | - Xiaoyan Li
- Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Meng Li
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China.
| | - Ji-Dong Gu
- Environmental Engineering, Guangdong Technion - Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China; Southern Laboratory of Ocean Science and Engineering, Zhuhai, Guangdong, China.
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Mycobacterium smegmatis does not display functional redundancy in nitrate reductase enzymes. PLoS One 2021; 16:e0245745. [PMID: 33471823 PMCID: PMC7816997 DOI: 10.1371/journal.pone.0245745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 01/06/2021] [Indexed: 12/04/2022] Open
Abstract
Reduction of nitrate to nitrite in bacteria is an essential step in the nitrogen cycle, catalysed by a variety of nitrate reductase (NR) enzymes. The soil dweller, Mycobacterium smegmatis is able to assimilate nitrate and herein we set out to confirm the genetic basis for this by probing NR activity in mutants defective for putative nitrate reductase (NR) encoding genes. In addition to the annotated narB and narGHJI, bioinformatics identified three other putative NR-encoding genes: MSMEG_4206, MSMEG_2237 and MSMEG_6816. To assess the relative contribution of each, the corresponding gene loci were deleted using two-step allelic replacement, individually and in combination. The resulting strains were tested for their ability to assimilate nitrate and reduce nitrate under aerobic and anaerobic conditions, using nitrate assimilation and modified Griess assays. We demonstrated that narB, narGHJI, MSMEG_2237 and MSMEG_6816 were individually dispensable for nitrate assimilation and for nitrate reductase activity under aerobic and anaerobic conditions. Only deletion of MSMEG_4206 resulted in significant reduction in nitrate assimilation under aerobic conditions. These data confirm that in M. smegmatis, narB, narGHJI, MSMEG_2237 and MSMEG_6816 are not required for nitrate reduction as MSMEG_4206 serves as the sole assimilatory NR.
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Trace gas oxidizers are widespread and active members of soil microbial communities. Nat Microbiol 2021; 6:246-256. [PMID: 33398096 DOI: 10.1038/s41564-020-00811-w] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/08/2020] [Indexed: 01/24/2023]
Abstract
Soil microorganisms globally are thought to be sustained primarily by organic carbon sources. Certain bacteria also consume inorganic energy sources such as trace gases, but they are presumed to be rare community members, except within some oligotrophic soils. Here we combined metagenomic, biogeochemical and modelling approaches to determine how soil microbial communities meet energy and carbon needs. Analysis of 40 metagenomes and 757 derived genomes indicated that over 70% of soil bacterial taxa encode enzymes to consume inorganic energy sources. Bacteria from 19 phyla encoded enzymes to use the trace gases hydrogen and carbon monoxide as supplemental electron donors for aerobic respiration. In addition, we identified a fourth phylum (Gemmatimonadota) potentially capable of aerobic methanotrophy. Consistent with the metagenomic profiling, communities within soil profiles from diverse habitats rapidly oxidized hydrogen, carbon monoxide and to a lesser extent methane below atmospheric concentrations. Thermodynamic modelling indicated that the power generated by oxidation of these three gases is sufficient to meet the maintenance needs of the bacterial cells capable of consuming them. Diverse bacteria also encode enzymes to use trace gases as electron donors to support carbon fixation. Altogether, these findings indicate that trace gas oxidation confers a major selective advantage in soil ecosystems, where availability of preferred organic substrates limits microbial growth. The observation that inorganic energy sources may sustain most soil bacteria also has broad implications for understanding atmospheric chemistry and microbial biodiversity in a changing world.
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36
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Ko EM, Oh JI. Induction of the cydAB Operon Encoding the bd Quinol Oxidase Under Respiration-Inhibitory Conditions by the Major cAMP Receptor Protein MSMEG_6189 in Mycobacterium smegmatis. Front Microbiol 2020; 11:608624. [PMID: 33343552 PMCID: PMC7739888 DOI: 10.3389/fmicb.2020.608624] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/06/2020] [Indexed: 12/29/2022] Open
Abstract
The respiratory electron transport chain (ETC) of Mycobacterium smegmatis is terminated with two terminal oxidases, the aa 3 cytochrome c oxidase and the cytochrome bd quinol oxidase. The bd quinol oxidase with a higher binding affinity for O2 than the aa 3 oxidase is known to play an important role in aerobic respiration under oxygen-limiting conditions. Using relevant crp1 (MSMEG_6189) and crp2 (MSMEG_0539) mutant strains of M. smegmatis, we demonstrated that Crp1 plays a predominant role in induction of the cydAB operon under ETC-inhibitory conditions. Two Crp-binding sequences were identified upstream of the cydA gene, both of which are necessary for induction of cydAB expression under ETC-inhibitory conditions. The intracellular level of cAMP in M. smegmatis was found to be increased under ETC-inhibitory conditions. The crp2 gene was found to be negatively regulated by Crp1 and Crp2, which appears to lead to significantly low cellular abundance of Crp2 relative to Crp1 in M. smegmatis. Our RNA sequencing analyses suggest that in addition to the SigF partner switching system, Crp1 is involved in induction of gene expression in M. smegmatis exposed to ETC-inhibitory conditions.
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Affiliation(s)
- Eon-Min Ko
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
| | - Jeong-Il Oh
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
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37
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Ray AE, Zhang E, Terauds A, Ji M, Kong W, Ferrari BC. Soil Microbiomes With the Genetic Capacity for Atmospheric Chemosynthesis Are Widespread Across the Poles and Are Associated With Moisture, Carbon, and Nitrogen Limitation. Front Microbiol 2020; 11:1936. [PMID: 32903524 PMCID: PMC7437527 DOI: 10.3389/fmicb.2020.01936] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 07/22/2020] [Indexed: 11/13/2022] Open
Abstract
Soil microbiomes within oligotrophic cold deserts are extraordinarily diverse. Increasingly, oligotrophic sites with low levels of phototrophic primary producers are reported, leading researchers to question their carbon and energy sources. A novel microbial carbon fixation process termed atmospheric chemosynthesis recently filled this gap as it was shown to be supporting primary production at two Eastern Antarctic deserts. Atmospheric chemosynthesis uses energy liberated from the oxidation of atmospheric hydrogen to drive the Calvin-Benson-Bassham (CBB) cycle through a new chemotrophic form of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), designated IE. Here, we propose that the genetic determinants of this process; RuBisCO type IE (rbcL1E) and high affinity group 1h-[NiFe]-hydrogenase (hhyL) are widespread across cold desert soils and that this process is linked to dry and nutrient-poor environments. We used quantitative PCR (qPCR) to quantify these genes in 122 soil microbiomes across the three poles; spanning the Tibetan Plateau, 10 Antarctic and three high Arctic sites. Both genes were ubiquitous, being present at variable abundances in all 122 soils examined (rbcL1E, 6.25 × 103–1.66 × 109 copies/g soil; hhyL, 6.84 × 103–5.07 × 108 copies/g soil). For the Antarctic and Arctic sites, random forest and correlation analysis against 26 measured soil physicochemical parameters revealed that rbcL1E and hhyL genes were associated with lower soil moisture, carbon and nitrogen content. While further studies are required to quantify the rates of trace gas carbon fixation and the organisms involved, we highlight the global potential of desert soil microbiomes to be supported by this new minimalistic mode of carbon fixation, particularly throughout dry oligotrophic environments, which encompass more than 35% of the Earth’s surface.
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Affiliation(s)
- Angelique E Ray
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Eden Zhang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Aleks Terauds
- Australian Antarctic Division, Department of Environment, Antarctic Conservation and Management, Kingston, TAS, Australia
| | - Mukan Ji
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Weidong Kong
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Belinda C Ferrari
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
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Panwar P, Allen MA, Williams TJ, Hancock AM, Brazendale S, Bevington J, Roux S, Páez-Espino D, Nayfach S, Berg M, Schulz F, Chen IMA, Huntemann M, Shapiro N, Kyrpides NC, Woyke T, Eloe-Fadrosh EA, Cavicchioli R. Influence of the polar light cycle on seasonal dynamics of an Antarctic lake microbial community. MICROBIOME 2020; 8:116. [PMID: 32772914 PMCID: PMC7416419 DOI: 10.1186/s40168-020-00889-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/30/2020] [Indexed: 05/10/2023]
Abstract
BACKGROUND Cold environments dominate the Earth's biosphere and microbial activity drives ecosystem processes thereby contributing greatly to global biogeochemical cycles. Polar environments differ to all other cold environments by experiencing 24-h sunlight in summer and no sunlight in winter. The Vestfold Hills in East Antarctica contains hundreds of lakes that have evolved from a marine origin only 3000-7000 years ago. Ace Lake is a meromictic (stratified) lake from this region that has been intensively studied since the 1970s. Here, a total of 120 metagenomes representing a seasonal cycle and four summers spanning a 10-year period were analyzed to determine the effects of the polar light cycle on microbial-driven nutrient cycles. RESULTS The lake system is characterized by complex sulfur and hydrogen cycling, especially in the anoxic layers, with multiple mechanisms for the breakdown of biopolymers present throughout the water column. The two most abundant taxa are phototrophs (green sulfur bacteria and cyanobacteria) that are highly influenced by the seasonal availability of sunlight. The extent of the Chlorobium biomass thriving at the interface in summer was captured in underwater video footage. The Chlorobium abundance dropped from up to 83% in summer to 6% in winter and 1% in spring, before rebounding to high levels. Predicted Chlorobium viruses and cyanophage were also abundant, but their levels did not negatively correlate with their hosts. CONCLUSION Over-wintering expeditions in Antarctica are logistically challenging, meaning insight into winter processes has been inferred from limited data. Here, we found that in contrast to chemolithoautotrophic carbon fixation potential of Southern Ocean Thaumarchaeota, this marine-derived lake evolved a reliance on photosynthesis. While viruses associated with phototrophs also have high seasonal abundance, the negative impact of viral infection on host growth appeared to be limited. The microbial community as a whole appears to have developed a capacity to generate biomass and remineralize nutrients, sufficient to sustain itself between two rounds of sunlight-driven summer-activity. In addition, this unique metagenome dataset provides considerable opportunity for future interrogation of eukaryotes and their viruses, abundant uncharacterized taxa (i.e. dark matter), and for testing hypotheses about endemic species in polar aquatic ecosystems. Video Abstract.
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Affiliation(s)
- Pratibha Panwar
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Michelle A Allen
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Timothy J Williams
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Alyce M Hancock
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Tasmania, Australia
| | - Sarah Brazendale
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
- , 476 Lancaster Rd, Pegarah, Australia
| | - James Bevington
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Simon Roux
- Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - David Páez-Espino
- Department of Energy Joint Genome Institute, Berkeley, CA, USA
- Mammoth BioSciences, 279 East Grand Ave, South San Francisco, CA, USA
| | - Stephen Nayfach
- Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Maureen Berg
- Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Frederik Schulz
- Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - I-Min A Chen
- Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | | | - Nicole Shapiro
- Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | | | - Tanja Woyke
- Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | | | - Ricardo Cavicchioli
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia.
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A widely distributed hydrogenase oxidises atmospheric H 2 during bacterial growth. ISME JOURNAL 2020; 14:2649-2658. [PMID: 32647310 PMCID: PMC7784904 DOI: 10.1038/s41396-020-0713-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/25/2020] [Accepted: 06/30/2020] [Indexed: 11/09/2022]
Abstract
Diverse aerobic bacteria persist by consuming atmospheric hydrogen (H2) using group 1h [NiFe]-hydrogenases. However, other hydrogenase classes are also distributed in aerobes, including the group 2a [NiFe]-hydrogenase. Based on studies focused on Cyanobacteria, the reported physiological role of the group 2a [NiFe]-hydrogenase is to recycle H2 produced by nitrogenase. However, given this hydrogenase is also present in various heterotrophs and lithoautotrophs lacking nitrogenases, it may play a wider role in bacterial metabolism. Here we investigated the role of this enzyme in three species from different phylogenetic lineages and ecological niches: Acidithiobacillus ferrooxidans (phylum Proteobacteria), Chloroflexus aggregans (phylum Chloroflexota), and Gemmatimonas aurantiaca (phylum Gemmatimonadota). qRT-PCR analysis revealed that the group 2a [NiFe]-hydrogenase of all three species is significantly upregulated during exponential growth compared to stationary phase, in contrast to the profile of the persistence-linked group 1h [NiFe]-hydrogenase. Whole-cell biochemical assays confirmed that all three strains aerobically respire H2 to sub-atmospheric levels, and oxidation rates were much higher during growth. Moreover, the oxidation of H2 supported mixotrophic growth of the carbon-fixing strains C. aggregans and A. ferrooxidans. Finally, we used phylogenomic analyses to show that this hydrogenase is widely distributed and is encoded by 13 bacterial phyla. These findings challenge the current persistence-centric model of the physiological role of atmospheric H2 oxidation and extend this process to two more phyla, Proteobacteria and Gemmatimonadota. In turn, these findings have broader relevance for understanding how bacteria conserve energy in different environments and control the biogeochemical cycling of atmospheric trace gases.
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Ntagia E, Chatzigiannidou I, Williamson AJ, Arends JBA, Rabaey K. Homoacetogenesis and microbial community composition are shaped by pH and total sulfide concentration. Microb Biotechnol 2020; 13:1026-1038. [PMID: 32126162 PMCID: PMC7264883 DOI: 10.1111/1751-7915.13546] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 02/08/2020] [Accepted: 02/10/2020] [Indexed: 12/27/2022] Open
Abstract
Biological CO2 sequestration through acetogenesis with H2 as electron donor is a promising technology to reduce greenhouse gas emissions. Today, a major issue is the presence of impurities such as hydrogen sulfide (H2 S) in CO2 containing gases, as they are known to inhibit acetogenesis in CO2 -based fermentations. However, exact values of toxicity and inhibition are not well-defined. To tackle this uncertainty, a series of toxicity experiments were conducted, with a mixed homoacetogenic culture, total dissolved sulfide concentrations ([TDS]) varied between 0 and 5 mM and pH between 5 and 7. The extent of inhibition was evaluated based on acetate production rates and microbial growth. Maximum acetate production rates of 0.12, 0.09 and 0.04 mM h-1 were achieved in the controls without sulfide at pH 7, pH 6 and pH 5. The half-maximal inhibitory concentration (IC50 qAc ) was 0.86, 1.16 and 1.36 mM [TDS] for pH 7, pH 6 and pH 5. At [TDS] above 3.33 mM, acetate production and microbial growth were completely inhibited at all pHs. 16S rRNA gene amplicon sequencing revealed major community composition transitions that could be attributed to both pH and [TDS]. Based on the observed toxicity levels, treatment approaches for incoming industrial CO2 streams can be determined.
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Affiliation(s)
- Eleftheria Ntagia
- Center for Microbial Ecology and Technology (CMET)Ghent UniversityCoupure Links 653Ghent9000Belgium
| | - Ioanna Chatzigiannidou
- Center for Microbial Ecology and Technology (CMET)Ghent UniversityCoupure Links 653Ghent9000Belgium
| | - Adam J. Williamson
- Center for Microbial Ecology and Technology (CMET)Ghent UniversityCoupure Links 653Ghent9000Belgium
| | - Jan B. A. Arends
- Center for Microbial Ecology and Technology (CMET)Ghent UniversityCoupure Links 653Ghent9000Belgium
| | - Korneel Rabaey
- Center for Microbial Ecology and Technology (CMET)Ghent UniversityCoupure Links 653Ghent9000Belgium
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41
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Abstract
Significance: Reducing equivalents (NAD(P)H and glutathione [GSH]) are essential for maintaining cellular redox homeostasis and for modulating cellular metabolism. Reductive stress induced by excessive levels of reduced NAD+ (NADH), reduced NADP+ (NADPH), and GSH is as harmful as oxidative stress and is implicated in many pathological processes. Recent Advances: Reductive stress broadens our view of the importance of cellular redox homeostasis and the influences of an imbalanced redox niche on biological functions, including cell metabolism. Critical Issues: The distribution of cellular NAD(H), NADP(H), and GSH/GSH disulfide is highly compartmentalized. Understanding how cells coordinate different pools of redox couples under unstressed and stressed conditions is critical for a comprehensive view of redox homeostasis and stress. It is also critical to explore the underlying mechanisms of reductive stress and its biological consequences, including effects on energy metabolism. Future Directions: Future studies are needed to investigate how reductive stress affects cell metabolism and how cells adapt their metabolism to reductive stress. Whether or not NADH shuttles and mitochondrial nicotinamide nucleotide transhydrogenase enzyme can regulate hypoxia-induced reductive stress is also a worthy pursuit. Developing strategies (e.g., antireductant approaches) to counteract reductive stress and its related adverse biological consequences also requires extensive future efforts.
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Affiliation(s)
- Wusheng Xiao
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Joseph Loscalzo
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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42
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Mavi PS, Singh S, Kumar A. Reductive Stress: New Insights in Physiology and Drug Tolerance of Mycobacterium. Antioxid Redox Signal 2020; 32:1348-1366. [PMID: 31621379 DOI: 10.1089/ars.2019.7867] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Significance:Mycobacterium tuberculosis (Mtb) encounters reductive stress during its infection cycle. Notably, host-generated protective responses, such as acidic pH inside phagosomes and lysosomes, exposure to glutathione in alveolar hypophase (i.e., a thin liquid lining consisting of surfactant and proteins in the alveolus), and hypoxic environments inside granulomas are associated with the accumulation of reduced cofactors, such as nicotinamide adenine dinucleotide (reduced form), nicotinamide adenine dinucleotide phosphate, flavin adenine dinucleotide (reduced form), and nonprotein thiols (e.g., mycothiol), leading to reductive stress in Mtb cells. Dissipation of this reductive stress is important for survival of the bacterium. If reductive stress is not dissipated, it leads to generation of reactive oxygen species, which may be fatal for the cells. Recent Advances: This review focuses on mechanisms utilized by mycobacteria to sense and respond to reductive stress. Importantly, exposure of Mtb cells to reductive stress leads to growth inhibition, altered metabolism, modulation of virulence, and drug tolerance. Mtb is equipped with thiol buffering systems of mycothiol and ergothioneine to protect itself from various redox stresses. These systems are complemented by thioredoxin and thioredoxin reductase (TR) systems for maintaining cellular redox homeostasis. A diverse array of sensors is used by Mycobacterium for monitoring its intracellular redox status. Upon sensing reductive stress, Mtb uses a flexible and robust metabolic system for its dissipation. Branched electron transport chain allows Mycobacterium to function with different terminal electron acceptors and modulate proton motive force to fulfill energy requirements under diverse scenarios. Interestingly, Mtb utilizes variations in the tricarboxylic cycle and a number of dehydrogenases to dissipate reductive stress. Upon prolonged exposure to reductive stress, Mtb utilizes biosynthesis of storage and virulence lipids as a dissipative mechanism. Critical Issues: The mechanisms utilized by Mycobacterium for sensing and tackling reductive stress are not well characterized. Future Directions: The precise role of thiol buffering and TR systems in neutralizing reductive stress is not well defined. Genetic systems that respond to metabolic reductive stress and thiol reductive stress need to be mapped. Genetic screens could aid in identification of such systems. Given that management of reductive stress is critical for both actively replicating and persister mycobacteria, an improved understanding of the mechanisms used by mycobacteria for dissipation of reductive stress may lead to identification of vulnerable choke points that could be targeted for killing Mtb in vivo.
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Affiliation(s)
- Parminder Singh Mavi
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India
| | - Shweta Singh
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India
| | - Ashwani Kumar
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India.,Academy of Scientific and Innovative Research, Ghaziabad, India
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43
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Ciemniecki JA, Newman DK. The Potential for Redox-Active Metabolites To Enhance or Unlock Anaerobic Survival Metabolisms in Aerobes. J Bacteriol 2020; 202:e00797-19. [PMID: 32071098 PMCID: PMC7221258 DOI: 10.1128/jb.00797-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Classifying microorganisms as "obligate" aerobes has colloquially implied death without air, leading to the erroneous assumption that, without oxygen, they are unable to survive. However, over the past few decades, more than a few obligate aerobes have been found to possess anaerobic energy conservation strategies that sustain metabolic activity in the absence of growth or at very low growth rates. Similarly, studies emphasizing the aerobic prowess of certain facultative aerobes have sometimes led to underrecognition of their anaerobic capabilities. Yet an inescapable consequence of the affinity both obligate and facultative aerobes have for oxygen is that the metabolism of these organisms may drive this substrate to scarcity, making anoxic survival an essential skill. To illustrate this, we highlight the importance of anaerobic survival strategies for Pseudomonas aeruginosa and Streptomyces coelicolor, representative facultative and obligate aerobes, respectively. Included among these strategies, we describe a role for redox-active secondary metabolites (RAMs), such as phenazines made by P. aeruginosa, in enhancing substrate-level phosphorylation. Importantly, RAMs are made by diverse bacteria, often during stationary phase in the absence of oxygen, and can sustain anoxic survival. We present a hypothesis for how RAMs may enhance or even unlock energy conservation pathways that facilitate the anaerobic survival of both RAM producers and nonproducers.
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Affiliation(s)
- John A Ciemniecki
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Dianne K Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
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44
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Arjes HA, Vo L, Dunn CM, Willis L, DeRosa CA, Fraser CL, Kearns DB, Huang KC. Biosurfactant-Mediated Membrane Depolarization Maintains Viability during Oxygen Depletion in Bacillus subtilis. Curr Biol 2020; 30:1011-1022.e6. [PMID: 32059765 PMCID: PMC7153240 DOI: 10.1016/j.cub.2020.01.073] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 12/09/2019] [Accepted: 01/23/2020] [Indexed: 12/26/2022]
Abstract
The presence or absence of oxygen in the environment is a strong effector of cellular metabolism and physiology. Like many eukaryotes and some bacteria, Bacillus subtilis primarily utilizes oxygen during respiration to generate ATP. Despite the importance of oxygen for B. subtilis survival, we know little about how populations adapt to shifts in oxygen availability. Here, we find that when oxygen was depleted from stationary phase B. subtilis cultures, ∼90% of cells died while the remaining cells maintained colony-forming ability. We discover that production of the antimicrobial surfactin confers two oxygen-related fitness benefits: it increases aerobic growth yield by increasing oxygen diffusion, and it maintains viability during oxygen depletion by depolarizing the membrane. Strains unable to produce surfactin exhibited an ∼50-fold reduction in viability after oxygen depletion. Surfactin treatment of these cells led to membrane depolarization and reduced ATP production. Chemical and genetic perturbations that alter oxygen consumption or redox state support a model in which surfactin-mediated membrane depolarization maintains viability through slower oxygen consumption and/or a shift to a more reduced metabolic profile. These findings highlight the importance of membrane potential in regulating cell physiology and growth, and demonstrate that antimicrobials that depolarize cell membranes can benefit cells when the terminal electron acceptor in respiration is limiting. This foundational knowledge has deep implications for environmental microbiology, clinical anti-bacterial therapy, and industrial biotechnology.
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Affiliation(s)
- Heidi A Arjes
- Department of Bioengineering, Stanford University School of Medicine, 443 via Ortega, Stanford, CA 94305, USA
| | - Lam Vo
- Department of Bioengineering, Stanford University School of Medicine, 443 via Ortega, Stanford, CA 94305, USA
| | - Caroline M Dunn
- Department of Biology, 1001 E 3rd Street, Indiana University, Bloomington, IN 47405, USA
| | - Lisa Willis
- Department of Bioengineering, Stanford University School of Medicine, 443 via Ortega, Stanford, CA 94305, USA
| | - Christopher A DeRosa
- Department of Chemistry, McCormick Road, University of Virginia, Charlottesville, VA 22904, USA
| | - Cassandra L Fraser
- Department of Chemistry, McCormick Road, University of Virginia, Charlottesville, VA 22904, USA
| | - Daniel B Kearns
- Department of Biology, 1001 E 3rd Street, Indiana University, Bloomington, IN 47405, USA.
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University School of Medicine, 443 via Ortega, Stanford, CA 94305, USA; Department of Microbiology & Immunology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, 499 Illinois Street, San Francisco, CA 94158, USA.
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45
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Yang Y, Daims H, Liu Y, Herbold CW, Pjevac P, Lin JG, Li M, Gu JD. Activity and Metabolic Versatility of Complete Ammonia Oxidizers in Full-Scale Wastewater Treatment Systems. mBio 2020; 11:e03175-19. [PMID: 32184251 PMCID: PMC7078480 DOI: 10.1128/mbio.03175-19] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 02/06/2020] [Indexed: 11/20/2022] Open
Abstract
The recent discovery of complete ammonia oxidizers (comammox) contradicts the paradigm that chemolithoautotrophic nitrification is always catalyzed by two different microorganisms. However, our knowledge of the survival strategies of comammox in complex ecosystems, such as full-scale wastewater treatment plants (WWTPs), remains limited. Analyses of genomes and in situ transcriptomes of four comammox organisms from two full-scale WWTPs revealed that comammox were active and showed a surprisingly high metabolic versatility. A gene cluster for the utilization of urea and a gene encoding cyanase suggest that comammox may use diverse organic nitrogen compounds in addition to free ammonia as the substrates. The comammox organisms also encoded the genomic potential for multiple alternative energy metabolisms, including respiration with hydrogen, formate, and sulfite as electron donors. Pathways for the biosynthesis and degradation of polyphosphate, glycogen, and polyhydroxyalkanoates as intracellular storage compounds likely help comammox survive unfavorable conditions and facilitate switches between lifestyles in fluctuating environments. One of the comammox strains acquired from the anaerobic tank encoded and transcribed genes involved in homoacetate fermentation or in the utilization of exogenous acetate, both pathways being unexpected in a nitrifying bacterium. Surprisingly, this strain also encoded a respiratory nitrate reductase which has not yet been found in any other Nitrospira genome and might confer a selective advantage to this strain over other Nitrospira strains in anoxic conditions.IMPORTANCE The discovery of comammox in the genus Nitrospira changes our perception of nitrification. However, genomes of comammox organisms have not been acquired from full-scale WWTPs, and very little is known about their survival strategies and potential metabolisms in complex wastewater treatment systems. Here, four comammox metagenome-assembled genomes and metatranscriptomic data sets were retrieved from two full-scale WWTPs. Their impressive and-among nitrifiers-unsurpassed ecophysiological versatility could make comammox Nitrospira an interesting target for optimizing nitrification in current and future bioreactor configurations.
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Affiliation(s)
- Yuchun Yang
- Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, Hong Kong, People's Republic of China
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, People's Republic of China
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, Vienna, Austria
| | - Holger Daims
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, Vienna, Austria
- University of Vienna, The Comammox Research Platform, Vienna, Austria
| | - Yang Liu
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, People's Republic of China
| | - Craig W Herbold
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, Vienna, Austria
| | - Petra Pjevac
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, Vienna, Austria
- Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Vienna, Austria
| | - Jih-Gaw Lin
- Institute of Environmental Engineering, National Chiao Tung University, Hsinchu City, Taiwan
| | - Meng Li
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, People's Republic of China
| | - Ji-Dong Gu
- Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, Hong Kong, People's Republic of China
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46
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Benoit SL, Maier RJ, Sawers RG, Greening C. Molecular Hydrogen Metabolism: a Widespread Trait of Pathogenic Bacteria and Protists. Microbiol Mol Biol Rev 2020; 84:e00092-19. [PMID: 31996394 PMCID: PMC7167206 DOI: 10.1128/mmbr.00092-19] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pathogenic microorganisms use various mechanisms to conserve energy in host tissues and environmental reservoirs. One widespread but often overlooked means of energy conservation is through the consumption or production of molecular hydrogen (H2). Here, we comprehensively review the distribution, biochemistry, and physiology of H2 metabolism in pathogens. Over 200 pathogens and pathobionts carry genes for hydrogenases, the enzymes responsible for H2 oxidation and/or production. Furthermore, at least 46 of these species have been experimentally shown to consume or produce H2 Several major human pathogens use the large amounts of H2 produced by colonic microbiota as an energy source for aerobic or anaerobic respiration. This process has been shown to be critical for growth and virulence of the gastrointestinal bacteria Salmonella enterica serovar Typhimurium, Campylobacter jejuni, Campylobacter concisus, and Helicobacter pylori (including carcinogenic strains). H2 oxidation is generally a facultative trait controlled by central regulators in response to energy and oxidant availability. Other bacterial and protist pathogens produce H2 as a diffusible end product of fermentation processes. These include facultative anaerobes such as Escherichia coli, S Typhimurium, and Giardia intestinalis, which persist by fermentation when limited for respiratory electron acceptors, as well as obligate anaerobes, such as Clostridium perfringens, Clostridioides difficile, and Trichomonas vaginalis, that produce large amounts of H2 during growth. Overall, there is a rich literature on hydrogenases in growth, survival, and virulence in some pathogens. However, we lack a detailed understanding of H2 metabolism in most pathogens, especially obligately anaerobic bacteria, as well as a holistic understanding of gastrointestinal H2 transactions overall. Based on these findings, we also evaluate H2 metabolism as a possible target for drug development or other therapies.
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Affiliation(s)
- Stéphane L Benoit
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Robert J Maier
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - R Gary Sawers
- Institute of Microbiology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton, VIC, Australia
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47
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Andrews ESV, Arcus VL. PhoH2 proteins couple RNA helicase and RNAse activities. Protein Sci 2020; 29:883-892. [PMID: 31886915 DOI: 10.1002/pro.3814] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 01/29/2023]
Abstract
PhoH2 proteins are found in a very diverse range of microorganisms that span bacteria and archaea. These proteins are composed of two domains: an N-terminal PIN-domain fused with a C-terminal PhoH domain. Collectively this fusion functions as an RNA helicase and ribonuclease. In other genomic contexts, PINdomains and PhoHdomains are separate but adjacent suggesting association to achieve similar function. Exclusively among the mycobacteria, PhoH2 proteins are encoded in the genome with an upstream gene, phoAT, which is thought to play the role of an antitoxin (in place of the traditional VapB antitoxin that lies upstream of the 47 other PINdomains in the mycobacterial genome). This review examines PhoH2 proteins as a whole and describes the bioinformatics, biochemical, structural, and biological properties of the two domains that make up PhoH2: PIN and PhoH. We review the transcriptional regulators of phoH2 from two mycobacterial species and speculate on the function of PhoH2 proteins in the context of a Type II toxin-antitoxin system which are thought to play a role in the stress response in bacteria.
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Affiliation(s)
- Emma S V Andrews
- School of Science, Division of Health, Engineering, Computing and Science, University of Waikato, Hamilton, New Zealand
| | - Vickery L Arcus
- School of Science, Division of Health, Engineering, Computing and Science, University of Waikato, Hamilton, New Zealand
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48
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Hydrogen Does Not Appear To Be a Major Electron Donor for Symbiosis with the Deep-Sea Hydrothermal Vent Tubeworm Riftia pachyptila. Appl Environ Microbiol 2019; 86:AEM.01522-19. [PMID: 31628148 DOI: 10.1128/aem.01522-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 10/09/2019] [Indexed: 12/23/2022] Open
Abstract
Use of hydrogen gas (H2) as an electron donor is common among free-living chemolithotrophic microorganisms. Given the presence of this dissolved gas at deep-sea hydrothermal vents, it has been suggested that it may also be a major electron donor for the free-living and symbiotic chemolithoautotrophic bacteria that are the primary producers at these sites. Giant Riftia pachyptila siboglinid tubeworms and their symbiotic bacteria ("Candidatus Endoriftia persephone") dominate many vents in the Eastern Pacific, and their use of sulfide as a major electron donor has been documented. Genes encoding hydrogenase are present in the "Ca Endoriftia persephone" genome, and proteome data suggest that these genes are expressed. In this study, high-pressure respirometry of intact R. pachyptila and incubations of trophosome homogenate were used to determine whether this symbiotic association could also use H2 as a major electron donor. Measured rates of H2 uptake by intact R. pachyptila in high-pressure respirometers were similar to rates measured in the absence of tubeworms. Oxygen uptake rates in the presence of H2 were always markedly lower than those measured in the presence of sulfide, as was the incorporation of 13C-labeled dissolved inorganic carbon. Carbon fixation by trophosome homogenate was not stimulated by H2, nor was hydrogenase activity detectable in these samples. Though genes encoding [NiFe] group 1e and [NiFe] group 3b hydrogenases are present in the genome and transcribed, it does not appear that H2 is a major electron donor for this system, and it may instead play a role in intracellular redox homeostasis.IMPORTANCE Despite the presence of hydrogenase genes, transcripts, and proteins in the "Ca Endoriftia persephone" genome, transcriptome, and proteome, it does not appear that R. pachyptila can use H2 as a major electron donor. For many uncultivable microorganisms, omic analyses are the basis for inferences about their activities in situ However, as is apparent from the study reported here, there are dangers in extrapolating from omics data to function, and it is essential, whenever possible, to verify functions predicted from omics data with physiological and biochemical measurements.
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49
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Islam ZF, Cordero PRF, Greening C. Putative Iron-Sulfur Proteins Are Required for Hydrogen Consumption and Enhance Survival of Mycobacteria. Front Microbiol 2019; 10:2749. [PMID: 31824474 PMCID: PMC6883350 DOI: 10.3389/fmicb.2019.02749] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 11/12/2019] [Indexed: 01/01/2023] Open
Abstract
Aerobic soil bacteria persist by scavenging molecular hydrogen (H2) from the atmosphere. This key process is the primary sink in the biogeochemical hydrogen cycle and supports the productivity of oligotrophic ecosystems. In Mycobacterium smegmatis, atmospheric H2 oxidation is catalyzed by two phylogenetically distinct [NiFe]-hydrogenases, Huc (group 2a) and Hhy (group 1h). However, it is currently unresolved how these enzymes transfer electrons derived from H2 oxidation into the aerobic respiratory chain. In this work, we used genetic approaches to confirm that two putative iron-sulfur cluster proteins encoded on the hydrogenase structural operons, HucE and HhyE, are required for H2 consumption in M. smegmatis. Sequence analysis show that these proteins, while homologous, fall into distinct phylogenetic clades and have distinct metal-binding motifs. H2 oxidation was reduced when the genes encoding these proteins were deleted individually and was eliminated when they were deleted in combination. In turn, the growth yield and long-term survival of these deletion strains was modestly but significantly reduced compared to the parent strain. In both biochemical and phenotypic assays, the mutant strains lacking the putative iron-sulfur proteins phenocopied those of hydrogenase structural subunit mutants. We hypothesize that these proteins mediate electron transfer between the catalytic subunits of the hydrogenases and the menaquinone pool of the M. smegmatis respiratory chain; however, other roles (e.g., in maturation) are also plausible and further work is required to resolve their role. The conserved nature of these proteins within most Hhy- or Huc-encoding organisms suggests that these proteins are important determinants of atmospheric H2 oxidation.
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Affiliation(s)
| | | | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
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50
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Hards K, Adolph C, Harold LK, McNeil MB, Cheung CY, Jinich A, Rhee KY, Cook GM. Two for the price of one: Attacking the energetic-metabolic hub of mycobacteria to produce new chemotherapeutic agents. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 152:35-44. [PMID: 31733221 DOI: 10.1016/j.pbiomolbio.2019.11.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/12/2019] [Indexed: 12/25/2022]
Abstract
Cellular bioenergetics is an area showing promise for the development of new antimicrobials, antimalarials and cancer therapy. Enzymes involved in central carbon metabolism and energy generation are essential mediators of bacterial physiology, persistence and pathogenicity, lending themselves natural interest for drug discovery. In particular, succinate and malate are two major focal points in both the central carbon metabolism and the respiratory chain of Mycobacterium tuberculosis. Both serve as direct links between the citric acid cycle and the respiratory chain due to the quinone-linked reactions of succinate dehydrogenase, fumarate reductase and malate:quinone oxidoreductase. Inhibitors against these enzymes therefore hold the promise of disrupting two distinct, but essential, cellular processes at the same time. In this review, we discuss the roles and unique adaptations of these enzymes and critically evaluate the role that future inhibitors of these complexes could play in the bioenergetics target space.
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Affiliation(s)
- Kiel Hards
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, 9054, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, 1042, Auckland, New Zealand.
| | - Cara Adolph
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, 9054, Dunedin, New Zealand
| | - Liam K Harold
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, 9054, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, 1042, Auckland, New Zealand
| | - Matthew B McNeil
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, 9054, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, 1042, Auckland, New Zealand
| | - Chen-Yi Cheung
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, 9054, Dunedin, New Zealand
| | - Adrian Jinich
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Kyu Y Rhee
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Gregory M Cook
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, 9054, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, 1042, Auckland, New Zealand.
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