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Wang B, Huang J, Yang J, Jiang H, Xiao H, Han J, Zhang X. Bicarbonate uptake rates and diversity of RuBisCO genes in saline lake sediments. FEMS Microbiol Ecol 2021; 97:6149456. [PMID: 33629724 DOI: 10.1093/femsec/fiab037] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 02/23/2021] [Indexed: 11/12/2022] Open
Abstract
There is limited knowledge of microbial carbon fixation rate, and carbon-fixing microbial abundance and diversity in saline lakes. In this study, the inorganic carbon uptake rates and carbon-fixing microbial populations were investigated in the surface sediments of lakes with a full range of salinity from freshwater to salt saturation. The results showed that in the studied lakes light-dependent bicarbonate uptake contributed substantially (>70%) to total bicarbonate uptake, while the contribution of dark bicarbonate uptake (1.35-25.17%) cannot be ignored. The light-dependent bicarbonate uptake rates were significantly correlated with pH and turbidity, while dark bicarbonate uptake rates were significantly influenced by dissolved inorganic carbon, pH, temperature and salinity. Carbon-fixing microbial populations using the Calvin-Benson-Bassham pathway were widespread in the studied lakes, and they were dominated by the cbbL and cbbM gene types affiliated with Cyanobacteria and Proteobacteria, respectively. The cbbL and cbbM gene abundance and population structures were significantly affected by different environmental variables, with the cbbL and cbbM genes being negatively correlated with salinity and organic carbon concentration, respectively. In summary, this study improves our knowledge of the abundance, diversity and function of carbon-fixing microbial populations in the lakes with a full range of salinity.
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Affiliation(s)
- Beichen Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China
| | - Jianrong Huang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China
| | - Jian Yang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China
| | - Hongchen Jiang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China.,State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
| | - Haiyi Xiao
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Jibin Han
- Key Laboratory of Salt Lake Geology and Environment of Qinghai Province, Qinghai Institute of Salt Lakes, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Xining 81008, China
| | - Xiying Zhang
- Key Laboratory of Salt Lake Geology and Environment of Qinghai Province, Qinghai Institute of Salt Lakes, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Xining 81008, China
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2
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Tahon G, Willems A. Isolation and characterization of aerobic anoxygenic phototrophs from exposed soils from the Sør Rondane Mountains, East Antarctica. Syst Appl Microbiol 2017; 40:357-369. [DOI: 10.1016/j.syapm.2017.05.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 12/24/2022]
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3
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Kadnikov VV, Ivasenko DA, Beletskii AV, Mardanov AV, Danilova EV, Pimenov NV, Karnachuk OV, Ravin NV. A novel uncultured bacterium of the family Gallionellaceae: Description and genome reconstruction based on metagenomic analysis of microbial community in acid mine drainage. Microbiology (Reading) 2016. [DOI: 10.1134/s002626171604010x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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4
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Varaljay VA, Satagopan S, North JA, Witte B, Dourado MN, Anantharaman K, Arbing MA, McCann SH, Oremland RS, Banfield JF, Wrighton KC, Tabita FR. Functional metagenomic selection of ribulose 1, 5-bisphosphate carboxylase/oxygenase from uncultivated bacteria. Environ Microbiol 2016; 18:1187-99. [PMID: 26617072 PMCID: PMC10035430 DOI: 10.1111/1462-2920.13138] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/17/2015] [Accepted: 11/17/2015] [Indexed: 01/29/2023]
Abstract
Ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) is a critical yet severely inefficient enzyme that catalyses the fixation of virtually all of the carbon found on Earth. Here, we report a functional metagenomic selection that recovers physiologically active RubisCO molecules directly from uncultivated and largely unknown members of natural microbial communities. Selection is based on CO2 -dependent growth in a host strain capable of expressing environmental deoxyribonucleic acid (DNA), precluding the need for pure cultures or screening of recombinant clones for enzymatic activity. Seventeen functional RubisCO-encoded sequences were selected using DNA extracted from soil and river autotrophic enrichments, a photosynthetic biofilm and a subsurface groundwater aquifer. Notably, three related form II RubisCOs were recovered which share high sequence similarity with metagenomic scaffolds from uncultivated members of the Gallionellaceae family. One of the Gallionellaceae RubisCOs was purified and shown to possess CO2 /O2 specificity typical of form II enzymes. X-ray crystallography determined that this enzyme is a hexamer, only the second form II multimer ever solved and the first RubisCO structure obtained from an uncultivated bacterium. Functional metagenomic selection leverages natural biological diversity and billions of years of evolution inherent in environmental communities, providing a new window into the discovery of CO2 -fixing enzymes not previously characterized.
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Affiliation(s)
- Vanessa A. Varaljay
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Sriram Satagopan
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Justin A. North
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Brian Witte
- The Botanical Research Institute of Texas, Fort Worth, TX 76107, USA
| | | | - Karthik Anantharaman
- Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA
| | - Mark A. Arbing
- Protein Expression Technology Center, UCLA-DOE Institute, University of California, Los Angeles, CA 90095, USA
| | | | | | - Jillian F. Banfield
- Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA
| | - Kelly C. Wrighton
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - F. Robert Tabita
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- For correspondence. ; Tel. +1 614 292 4297; Fax: +1 614 292 6337
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Tahon G, Tytgat B, Stragier P, Willems A. Analysis of cbbL, nifH, and pufLM in Soils from the Sør Rondane Mountains, Antarctica, Reveals a Large Diversity of Autotrophic and Phototrophic Bacteria. MICROBIAL ECOLOGY 2016; 71:131-149. [PMID: 26582318 DOI: 10.1007/s00248-015-0704-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 11/02/2015] [Indexed: 06/05/2023]
Abstract
Cyanobacteria are generally thought to be responsible for primary production and nitrogen fixation in the microbial communities that dominate Antarctic ecosystems. Recent studies of bacterial communities in terrestrial Antarctica, however, have shown that Cyanobacteria are sometimes only scarcely present, suggesting that other bacteria presumably take over their role as primary producers and diazotrophs. The diversity of key genes in these processes was studied in surface samples from the Sør Rondane Mountains, Dronning Maud Land, using clone libraries of the large subunit of ribulose-1,5-biphosphate carboxylase/oxygenase (RuBisCO) genes (cbbL, cbbM) and dinitrogenase-reductase (nifH) genes. We recovered a large diversity of non-cyanobacterial cbbL type IC in addition to cyanobacterial type IB, suggesting that non-cyanobacterial autotrophs may contribute to primary production. The nifH diversity recovered was predominantly related to Cyanobacteria, particularly members of the Nostocales. We also investigated the occurrence of proteorhodopsin and anoxygenic phototrophy as mechanisms for non-Cyanobacteria to exploit solar energy. While proteorhodopsin genes were not detected, a large diversity of genes coding for the light and medium subunits of the type 2 phototrophic reaction center (pufLM) was observed, suggesting for the first time, that the aerobic photoheterotrophic lifestyle may be important in oligotrophic high-altitude ice-free terrestrial Antarctic habitats.
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Affiliation(s)
- Guillaume Tahon
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium
| | - Bjorn Tytgat
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium
| | - Pieter Stragier
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium
| | - Anne Willems
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium.
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6
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Kato S, Ohkuma M, Powell DH, Krepski ST, Oshima K, Hattori M, Shapiro N, Woyke T, Chan CS. Comparative Genomic Insights into Ecophysiology of Neutrophilic, Microaerophilic Iron Oxidizing Bacteria. Front Microbiol 2015; 6:1265. [PMID: 26617599 PMCID: PMC4643136 DOI: 10.3389/fmicb.2015.01265] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/30/2015] [Indexed: 11/13/2022] Open
Abstract
Neutrophilic microaerophilic iron-oxidizing bacteria (FeOB) are thought to play a significant role in cycling of carbon, iron and associated elements in both freshwater and marine iron-rich environments. However, the roles of the neutrophilic microaerophilic FeOB are still poorly understood due largely to the difficulty of cultivation and lack of functional gene markers. Here, we analyze the genomes of two freshwater neutrophilic microaerophilic stalk-forming FeOB, Ferriphaselus amnicola OYT1 and Ferriphaselus strain R-1. Phylogenetic analyses confirm that these are distinct species within Betaproteobacteria; we describe strain R-1 and propose the name F. globulitus. We compare the genomes to those of two freshwater Betaproteobacterial and three marine Zetaproteobacterial FeOB isolates in order to look for mechanisms common to all FeOB, or just stalk-forming FeOB. The OYT1 and R-1 genomes both contain homologs to cyc2, which encodes a protein that has been shown to oxidize Fe in the acidophilic FeOB, Acidithiobacillus ferrooxidans. This c-type cytochrome common to all seven microaerophilic FeOB isolates, strengthening the case for its common utility in the Fe oxidation pathway. In contrast, the OYT1 and R-1 genomes lack mto genes found in other freshwater FeOB. OYT1 and R-1 both have genes that suggest they can oxidize sulfur species. Both have the genes necessary to fix carbon by the Calvin–Benson–Basshom pathway, while only OYT1 has the genes necessary to fix nitrogen. The stalk-forming FeOB share xag genes that may help form the polysaccharide structure of stalks. Both OYT1 and R-1 make a novel biomineralization structure, short rod-shaped Fe oxyhydroxides much smaller than their stalks; these oxides are constantly shed, and may be a vector for C, P, and metal transport to downstream environments. Our results show that while different FeOB are adapted to particular niches, freshwater and marine FeOB likely share common mechanisms for Fe oxidation electron transport and biomineralization pathways.
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Affiliation(s)
- Shingo Kato
- Department of Geological Sciences, University of Delaware, Newark DE, USA ; Japan Collection of Microorganisms, RIKEN BioResource Center Tsukuba, Japan
| | - Moriya Ohkuma
- Japan Collection of Microorganisms, RIKEN BioResource Center Tsukuba, Japan
| | - Deborah H Powell
- Delaware Biotechnology Institute, University of Delaware, Newark DE, USA
| | - Sean T Krepski
- Department of Geological Sciences, University of Delaware, Newark DE, USA
| | - Kenshiro Oshima
- Center for Omics and Bioinformatics, Graduate School of Frontier Sciences, University of Tokyo Kashiwa, Japan
| | - Masahira Hattori
- Center for Omics and Bioinformatics, Graduate School of Frontier Sciences, University of Tokyo Kashiwa, Japan
| | - Nicole Shapiro
- Department of Energy Joint Genome Institute, Walnut Creek CA, USA
| | - Tanja Woyke
- Department of Energy Joint Genome Institute, Walnut Creek CA, USA
| | - Clara S Chan
- Department of Geological Sciences, University of Delaware, Newark DE, USA
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Quantitative PCR analysis of functional genes in iron-rich microbial mats at an active hydrothermal vent system (Lō'ihi Seamount, Hawai'i). Appl Environ Microbiol 2015; 81:2976-84. [PMID: 25681182 DOI: 10.1128/aem.03608-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/09/2015] [Indexed: 01/22/2023] Open
Abstract
The chemolithotrophic Zetaproteobacteria represent a novel class of Proteobacteria which oxidize Fe(II) to Fe(III) and are the dominant bacterial population in iron-rich microbial mats. Zetaproteobacteria were first discovered at Lō'ihi Seamount, located 35 km southeast off the big island of Hawai'i, which is characterized by low-temperature diffuse hydrothermal venting. Novel nondegenerate quantitative PCR (qPCR) assays for genes associated with microbial nitrogen fixation, denitrification, arsenic detoxification, Calvin-Benson-Bassham (CBB), and reductive tricarboxylic acid (rTCA) cycles were developed using selected microbial mat community-derived metagenomes. Nitrogen fixation genes were not detected, but all other functional genes were present. This suggests that arsenic detoxification and denitrification processes are likely cooccurring in addition to two modes of carbon fixation. Two groups of microbial mat community types were identified by terminal restriction fragment length polymorphism (T-RFLP) and were further described based on qPCR data for zetaproteobacterial abundance and carbon fixation mode preference. qPCR variance was associated with mat morphology but not with temperature or sample site. Geochemistry data were significantly associated with sample site and mat morphology. Together, these qPCR assays constitute a functional gene signature for iron microbial mat communities across a broad array of temperatures, mat types, chemistries, and sampling sites at Lō'ihi Seamount.
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Kato S, Ikehata K, Shibuya T, Urabe T, Ohkuma M, Yamagishi A. Potential for biogeochemical cycling of sulfur, iron and carbon within massive sulfide deposits below the seafloor. Environ Microbiol 2014; 17:1817-35. [DOI: 10.1111/1462-2920.12648] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 08/13/2014] [Accepted: 09/25/2014] [Indexed: 02/06/2023]
Affiliation(s)
- Shingo Kato
- Department of Molecular Biology; Tokyo University of Pharmacy and Life Science; 1432-1 Horinouchi Hachioji Tokyo 192-0392 Japan
- Japan Collection of Microorganisms; RIKEN BioResource Center; 3-1-1 Koyadai Tsukuba Ibaraki 305-0074 Japan
| | - Kei Ikehata
- Faculty of Life and Environmental Sciences; University of Tsukuba; 1-1-1 Tennodai Tsukuba Ibaraki 305-8572 Japan
| | - Takazo Shibuya
- Submarine Resources Research Project (SRRP) & Precambrian Ecosystem Laboratory (PEL); Japan Agency for Marine-Earth Science and Technology (JAMSTEC); 2-15 Natsushima Yokosuka Kanagawa 237-0061 Japan
| | - Tetsuro Urabe
- Department of Earth and Planetary Science; University of Tokyo; Hongo Bunkyo-ku Tokyo 113-0033 Japan
| | - Moriya Ohkuma
- Japan Collection of Microorganisms; RIKEN BioResource Center; 3-1-1 Koyadai Tsukuba Ibaraki 305-0074 Japan
| | - Akihiko Yamagishi
- Department of Molecular Biology; Tokyo University of Pharmacy and Life Science; 1432-1 Horinouchi Hachioji Tokyo 192-0392 Japan
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Yousuf B, Kumar R, Mishra A, Jha B. Unravelling the carbon and sulphur metabolism in coastal soil ecosystems using comparative cultivation-independent genome-level characterisation of microbial communities. PLoS One 2014; 9:e107025. [PMID: 25225969 PMCID: PMC4167329 DOI: 10.1371/journal.pone.0107025] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 08/07/2014] [Indexed: 11/23/2022] Open
Abstract
Bacterial autotrophy contributes significantly to the overall carbon balance, which stabilises atmospheric CO2 concentration and decelerates global warming. Little attention has been paid to different modes of carbon/sulphur metabolism mediated by autotrophic bacterial communities in terrestrial soil ecosystems. We studied these pathways by analysing the distribution and abundance of the diagnostic metabolic marker genes cbbM, apsA and soxB, which encode for ribulose-1,5-bisphosphate carboxylase/oxygenase, adenosine phosphosulphate reductase and sulphate thiohydrolase, respectively, among different contrasting soil types. Additionally, the abundance of community members was assessed by quantifying the gene copy numbers for 16S rRNA, cbbL, cbbM, apsA and soxB. Distinct compositional differences were observed among the clone libraries, which revealed a dominance of phylotypes associated with carbon and sulphur cycling, such as Gammaproteobacteria (Thiohalomonas, Allochromatium, Chromatium, Thiomicrospira) and Alphaproteobacteria (Rhodopseudomonas, Rhodovulum, Paracoccus). The rhizosphere soil was devoid of sulphur metabolism, as the soxB and apsA genes were not observed in the rhizosphere metagenome, which suggests the absence or inadequate representation of sulphur-oxidising bacteria. We hypothesise that the novel Gammaproteobacteria sulphur oxidisers might be actively involved in sulphur oxidation and inorganic carbon fixation, particularly in barren saline soil ecosystems, suggesting their significant putative ecological role and contribution to the soil carbon pool.
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Affiliation(s)
- Basit Yousuf
- Discipline of Marine Biotechnology and Ecology, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India
- Academy of Scientific and Innovative Research, CSIR, New Delhi, India
| | - Raghawendra Kumar
- Discipline of Marine Biotechnology and Ecology, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India
- Academy of Scientific and Innovative Research, CSIR, New Delhi, India
| | - Avinash Mishra
- Discipline of Marine Biotechnology and Ecology, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India
- Academy of Scientific and Innovative Research, CSIR, New Delhi, India
- * E-mail: (AM); (BJ)
| | - Bhavanath Jha
- Discipline of Marine Biotechnology and Ecology, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India
- Academy of Scientific and Innovative Research, CSIR, New Delhi, India
- * E-mail: (AM); (BJ)
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10
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Xu W, Li M, Ding JF, Gu JD, Luo ZH. Bacteria dominate the ammonia-oxidizing community in a hydrothermal vent site at the Mid-Atlantic Ridge of the South Atlantic Ocean. Appl Microbiol Biotechnol 2014; 98:7993-8004. [DOI: 10.1007/s00253-014-5833-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 05/13/2014] [Accepted: 05/14/2014] [Indexed: 01/29/2023]
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Functional gene analysis of freshwater iron-rich flocs at circumneutral pH and isolation of a stalk-forming microaerophilic iron-oxidizing bacterium. Appl Environ Microbiol 2013; 79:5283-90. [PMID: 23811518 DOI: 10.1128/aem.03840-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Iron-rich flocs often occur where anoxic water containing ferrous iron encounters oxygenated environments. Culture-independent molecular analyses have revealed the presence of 16S rRNA gene sequences related to diverse bacteria, including autotrophic iron oxidizers and methanotrophs in iron-rich flocs; however, the metabolic functions of the microbial communities remain poorly characterized, particularly regarding carbon cycling. In the present study, we cultivated iron-oxidizing bacteria (FeOB) and performed clone library analyses of functional genes related to carbon fixation and methane oxidization (cbbM and pmoA, respectively), in addition to bacterial and archaeal 16S rRNA genes, in freshwater iron-rich flocs at groundwater discharge points. The analyses of 16S rRNA, cbbM, and pmoA genes strongly suggested the coexistence of autotrophic iron oxidizers and methanotrophs in the flocs. Furthermore, a novel stalk-forming microaerophilic FeOB, strain OYT1, was isolated and characterized phylogenetically and physiologically. The 16S rRNA and cbbM gene sequences of OYT1 are related to those of other microaerophilic FeOB in the family Gallionellaceae, of the Betaproteobacteria, isolated from freshwater environments at circumneutral pH. The physiological characteristics of OYT1 will help elucidate the ecophysiology of microaerophilic FeOB. Overall, this study demonstrates functional roles of microorganisms in iron flocs, suggesting several possible linkages between Fe and C cycling.
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12
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Olins HC, Rogers DR, Frank KL, Vidoudez C, Girguis PR. Assessing the influence of physical, geochemical and biological factors on anaerobic microbial primary productivity within hydrothermal vent chimneys. GEOBIOLOGY 2013; 11:279-293. [PMID: 23551687 DOI: 10.1111/gbi.12034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 02/25/2013] [Indexed: 06/02/2023]
Abstract
Chemosynthetic primary production supports hydrothermal vent ecosystems, but the extent of that productivity and its governing factors have not been well constrained. To better understand anaerobic primary production within massive vent deposits, we conducted a series of incubations at 4, 25, 50 and 90 °C using aggregates recovered from hydrothermal vent structures. We documented in situ geochemistry, measured autochthonous organic carbon stable isotope ratios and assessed microbial community composition and functional gene abundances in three hydrothermal vent chimney structures from Middle Valley on the Juan de Fuca Ridge. Carbon fixation rates were greatest at lower temperatures and were comparable among chimneys. Stable isotope ratios of autochthonous organic carbon were consistent with the Calvin-Benson-Bassham cycle being the predominant mode of carbon fixation for all three chimneys. Chimneys exhibited marked differences in vent fluid geochemistry and microbial community composition, with structures being differentially dominated by gamma (γ) or epsilon (ε) proteobacteria. Similarly, qPCR analyses of functional genes representing different carbon fixation pathways showed striking differences in gene abundance among chimney structures. Carbon fixation rates showed no obvious correlation with observed in situ vent fluid geochemistry, community composition or functional gene abundance. Together, these data reveal that (i) net anaerobic carbon fixation rates among these chimneys are elevated at lower temperatures, (ii) clear differences in community composition and gene abundance exist among chimney structures, and (iii) tremendous spatial heterogeneity within these environments likely confounds efforts to relate the observed rates to in situ microbial and geochemical factors. We also posit that microbes typically thought to be mesophiles are likely active and growing at cooler temperatures, and that their activity at these temperatures comprises the majority of endolithic anaerobic primary production in hydrothermal vent chimneys.
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Affiliation(s)
- H C Olins
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
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Kato S, Nakawake M, Kita J, Yamanaka T, Utsumi M, Okamura K, Ishibashi JI, Ohkuma M, Yamagishi A. Characteristics of microbial communities in crustal fluids in a deep-sea hydrothermal field of the suiyo seamount. Front Microbiol 2013; 4:85. [PMID: 23626587 PMCID: PMC3627986 DOI: 10.3389/fmicb.2013.00085] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Accepted: 03/27/2013] [Indexed: 12/04/2022] Open
Abstract
To directly access the sub-seafloor microbial communities, seafloor drilling has been done in a deep-sea hydrothermal field of the Suiyo Seamount, Izu-Bonin Arc, Western Pacific. In the present study, crustal fluids were collected from the boreholes, and the bacterial and archaeal communities in the fluids were investigated by culture-independent molecular analysis based on 16S rRNA gene sequences. Bottom seawater, sands, rocks, sulfide mound, and chimneys were also collected around the boreholes and analyzed for comparisons. Comprehensive analysis revealed the characteristics of the microbial community composition in the crustal fluids. Phylotypes closely related to cultured species, e.g., Alteromonas, Halomonas, Marinobacter, were relatively abundant in some crustal fluid samples, whereas the phylotypes related to Pelagibacter and the SUP05-group were relatively abundant in the seawater samples. Phylotypes related to other uncultured environmental clones in Alphaproteobacteria and Gammaproteobacteria were relatively abundant in the sand, rock, sulfide mound, and chimney samples. Furthermore, comparative analysis with previous studies of the Suiyo Seamount crustal fluids indicates the change in the microbial community composition for 3 years. Our results provide novel insights into the characteristics of the microbial communities in crustal fluids beneath a deep-sea hydrothermal field.
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Affiliation(s)
- Shingo Kato
- Japan Collection of Microorganisms, RIKEN BioResource Center Wako-shi, Saitama, Japan ; Department of Molecular Biology, Tokyo University of Pharmacy and Life Science Hachioji, Tokyo, Japan
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SUP05 dominates the Gammaproteobacterial sulfur oxidizer assemblages in pelagic redoxclines of the central Baltic and Black Seas. Appl Environ Microbiol 2013; 79:2767-76. [PMID: 23417000 DOI: 10.1128/aem.03777-12] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Gammaproteobacterial sulfur oxidizers (GSOs), particularly SUP05-related sequences, have been found worldwide in numerous oxygen-deficient marine environments. However, knowledge regarding their abundance, distribution, and ecological role is scarce. In this study, on the basis of phylogenetic analyses of 16S rRNA gene sequences originating from a Baltic Sea pelagic redoxcline, the in situ abundances of different GSO subgroups were quantified by CARD-FISH (catalyzed reporter fluorescence in situ hybridization) with oligonucleotide probes developed specifically for this purpose. Additionally, ribulose bisphosphate carboxylase/oxygenase form II (cbbM) gene transcript clone libraries were used to detect potential active chemolithoautotrophic GSOs in the Baltic Sea. Taken together, the results obtained by these two approaches demonstrated the existence of two major phylogenetic subclusters embedded within the GSO, one of them affiliated with sequences of the previously described SUP05 subgroup. CARD-FISH analyses revealed that only SUP05 occurred in relatively high numbers, reaching 10 to 30% of the total prokaryotes around the oxic-anoxic interface, where oxygen and sulfide concentrations are minimal. The applicability of the oligonucleotide probes was confirmed with samples from the Black Sea redoxcline, in which the SUP05 subgroup accounted for 10 to 13% of the total prokaryotic abundance. The cbbM transcripts presumably originating from SUP05 cells support previous evidence for the chemolithoautotrophic activity of this phylogenetic group. Our findings on the vertical distribution and high abundance of SUP05 suggest that this group plays an important role in marine redoxcline biogeochemistry, probably as anaerobic or aerobic sulfur oxidizers.
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