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Lingappa UF, Stein NT, Metcalfe KS, Present TM, Orphan VJ, Grotzinger JP, Knoll AH, Trower EJ, Gomes ML, Fischer WW. Early impacts of climate change on a coastal marine microbial mat ecosystem. SCIENCE ADVANCES 2022; 8:eabm7826. [PMID: 35622915 PMCID: PMC9140962 DOI: 10.1126/sciadv.abm7826] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 04/12/2022] [Indexed: 06/15/2023]
Abstract
Among the earliest consequences of climate change are extreme weather and rising sea levels-two challenges to which coastal environments are particularly vulnerable. Often found in coastal settings are microbial mats-complex, stratified microbial ecosystems that drive massive nutrient fluxes through biogeochemical cycles and have been important constituents of Earth's biosphere for eons. Little Ambergris Cay, in the Turks and Caicos Islands, supports extensive mats that vary sharply with relative water level. We characterized the microbial communities across this variation to understand better the emerging threat of sea level rise. In September 2017, the eyewall of category 5 Hurricane Irma transited the island. We monitored the impact and recovery from this devastating storm event. New mat growth proceeded rapidly, with patterns suggesting that storm perturbation may facilitate the adaptation of these ecosystems to changing sea level. Sulfur cycling, however, displayed hysteresis, stalling for >10 months after the hurricane and likely altering carbon storage potential.
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Affiliation(s)
- Usha F. Lingappa
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Nathaniel T. Stein
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Kyle S. Metcalfe
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Theodore M. Present
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Victoria J. Orphan
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - John P. Grotzinger
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Andrew H. Knoll
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Elizabeth J. Trower
- Department of Geological Sciences, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Maya L. Gomes
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Woodward W. Fischer
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
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He J, Zhang N, Muhammad A, Shen X, Sun C, Li Q, Hu Y, Shao Y. From surviving to thriving, the assembly processes of microbial communities in stone biodeterioration: A case study of the West Lake UNESCO World Heritage area in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 805:150395. [PMID: 34818768 DOI: 10.1016/j.scitotenv.2021.150395] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/13/2021] [Accepted: 09/13/2021] [Indexed: 05/11/2023]
Abstract
Serious concerns regarding stone biodeterioration have been raised due to the loss of aesthetic value and hidden dangers in stone cultural heritages and buildings. Stone biodeterioration involves a complex ecological interplay among organisms, however, the ecological mechanisms (deterministic or stochastic processes) that determine the microbial community on stone remain poorly understood. Here, using both amplicon and shotgun metagenomic sequencing approaches, we comprehensively investigated the biodiversity, assembly, and function of communities (including prokaryotes, fungi, microfauna, and plants) on various types of deteriorating limestone across different habitats in Feilaifeng. By generalizing classic ecological models to stone habitats, we further uncovered and quantified the mechanisms underlying microbial community assembly processes and microbial interactions within the biodeteriorated limestone. Community profiling revealed stable ecosystem functional potential despite high taxonomic variation across different biodeterioration types, suggesting non-random community assembly. Increased niche differentiation occurred in prokaryotes and fungi but not in microfauna and plant during biodeterioration. Certain microbial groups such as nitrifying archaea and bacteria showed wider niche breadth and likely contributing to the initiation, succession and expansion of stone biodeterioration. Consistently, prokaryotes were more strongly structured by selection-based deterministic processes, while micro-eukaryotes were more influenced by dispersal and drift-based stochastic processes. Importantly, microbial coexistence maintains network robustness within stone microbiotas, highlighting mutual cooperation among functional microorganisms. These results provide new insights into microbial community assembly mechanisms in stone ecosystems and may aid in the sustainable conservation of stone materials of interest.
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Affiliation(s)
- Jintao He
- Max Planck Partner Group, Institute of Sericulture and Apiculture, College of Animal Sciences, Faculty of Agriculture, Life and Environmental Sciences, Zhejiang University, Hangzhou, China
| | - Nan Zhang
- Max Planck Partner Group, Institute of Sericulture and Apiculture, College of Animal Sciences, Faculty of Agriculture, Life and Environmental Sciences, Zhejiang University, Hangzhou, China
| | - Abrar Muhammad
- Max Planck Partner Group, Institute of Sericulture and Apiculture, College of Animal Sciences, Faculty of Agriculture, Life and Environmental Sciences, Zhejiang University, Hangzhou, China
| | - Xiaoqiang Shen
- Max Planck Partner Group, Institute of Sericulture and Apiculture, College of Animal Sciences, Faculty of Agriculture, Life and Environmental Sciences, Zhejiang University, Hangzhou, China
| | - Chao Sun
- Analysis Center of Agrobiology and Environmental Sciences, Zhejiang University, Hangzhou, China
| | - Qiang Li
- Laboratory of Cultural Relics Conservation Materials, Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Yulan Hu
- School of Art and Archaeology, Zhejiang University, Hangzhou, China
| | - Yongqi Shao
- Max Planck Partner Group, Institute of Sericulture and Apiculture, College of Animal Sciences, Faculty of Agriculture, Life and Environmental Sciences, Zhejiang University, Hangzhou, China; Key Laboratory for Molecular Animal Nutrition, Ministry of Education, China.
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Jiménez-Jiménez C, Moreno VM, Vallet-Regí M. Bacteria-Assisted Transport of Nanomaterials to Improve Drug Delivery in Cancer Therapy. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:288. [PMID: 35055305 PMCID: PMC8781131 DOI: 10.3390/nano12020288] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/08/2022] [Accepted: 01/11/2022] [Indexed: 12/12/2022]
Abstract
Currently, the design of nanomaterials for the treatment of different pathologies is presenting a major impact on biomedical research. Thanks to this, nanoparticles represent a successful strategy for the delivery of high amounts of drugs for the treatment of cancer. Different nanosystems have been designed to combat this pathology. However, the poor penetration of these nanomaterials into the tumor tissue prevents the drug from entering the inner regions of the tumor. Some bacterial strains have self-propulsion and guiding capacity thanks to their flagella. They also have a preference to accumulate in certain tumor regions due to the presence of different chemo-attractants factors. Bioconjugation reactions allow the binding of nanoparticles in living systems, such as cells or bacteria, in a simple way. Therefore, bacteria are being used as a transport vehicle for nanoparticles, facilitating their penetration and the subsequent release of the drug inside the tumor. This review would summarize the literature on the anchoring methods of diverse nanosystems in bacteria and, interestingly, their advantages and possible applications in cancer therapy.
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Affiliation(s)
- Carla Jiménez-Jiménez
- CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, 28040 Madrid, Spain;
| | - Víctor M. Moreno
- Departamento de Química en Ciencias Farmacéuticas, Facultad de Farmacia, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria, Hospital 12 de Octubre i+12, 28040 Madrid, Spain;
| | - María Vallet-Regí
- CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, 28040 Madrid, Spain;
- Departamento de Química en Ciencias Farmacéuticas, Facultad de Farmacia, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria, Hospital 12 de Octubre i+12, 28040 Madrid, Spain;
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Wang YN, Kai Y, Wang L, Tsang YF, Fu X, Hu J, Xie Y. Key internal factors leading to the variability in CO 2 fixation efficiency of different sulfur-oxidizing bacteria during autotrophic cultivation. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 271:110957. [PMID: 32579519 DOI: 10.1016/j.jenvman.2020.110957] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 06/07/2020] [Accepted: 06/11/2020] [Indexed: 06/11/2023]
Abstract
Variability in the apparent CO2 fixation yield of four aerobic sulfur-oxidizing bacteria (Halothiobacillus neapolitanus DSM 15147, Thiobacillus thioparus DSM 505, Thiomonas intermedia DSM 18155, and Starkeya novella DSM 506) in autotrophic culturing was studied, and mutual effects of key intrinsic factors on CO2 fixation were explored. DSM 15147 and DSM 505 exhibited much higher CO2 fixation yields than DSM 18155 and DSM 506. The differences in CO2 fixation yield were determined not only by cbb gene transcription, but also by cell synthesis rate, which was determined by rRNA gene copy number; the rRNA gene copy number had a more significant effect than cbb gene transcription on the apparent CO2 fixation yield. Moreover, accumulation of EDOC was observed in all four strains during chemoautotrophic cultivation, and the proportion of EDOC accounting for total fixed organic carbon (TOC; EDOC/TOC ratio) was much higher in DSM 18155 and DSM 506 than in DSM 15147 and DSM 505. The accumulation of EDOC led to a significant decrease in the cbb gene transcription efficiency during cultivation, and a further feedback inhibitory effect on CO2 fixation.
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Affiliation(s)
- Ya-Nan Wang
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China
| | - Yan Kai
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China
| | - Lei Wang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Research Institute for Shanghai Pollution Control and Ecological Security, 200092, China.
| | - Yiu Fai Tsang
- Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, New Territories, SAR, Hong Kong, China.
| | - Xiaohua Fu
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Research Institute for Shanghai Pollution Control and Ecological Security, 200092, China
| | - Jiajun Hu
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai, 200444, China
| | - Yanjun Xie
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China
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Hot in Cold: Microbial Life in the Hottest Springs in Permafrost. Microorganisms 2020; 8:microorganisms8091308. [PMID: 32867302 PMCID: PMC7565842 DOI: 10.3390/microorganisms8091308] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 08/22/2020] [Accepted: 08/25/2020] [Indexed: 12/26/2022] Open
Abstract
Chukotka is an arctic region located in the continuous permafrost zone, but thermal springs are abundant there. In this study, for the first time, the microbial communities of the Chukotka hot springs (CHS) biofilms and sediments with temperatures 54–94 °C were investigated and analyzed by NGS sequencing of 16S rRNA gene amplicons. In microbial mats (54–75 °C), phototrophic bacteria of genus Chloroflexus dominated (up to 89% of all prokaryotes), while Aquificae were the most numerous at higher temperatures in Fe-rich sediments and filamentous “streamers” (up to 92%). The electron donors typical for Aquificae, such as H2S and H2, are absent or present only in trace amounts, and the prevalence of Aquificae might be connected with their ability to oxidize the ferrous iron present in CHS sediments. Armatimonadetes, Proteobacteria, Deinococcus-Thermus, Dictyoglomi, and Thermotogae, as well as uncultured bacteria (candidate divisions Oct-Spa1-106, GAL15, and OPB56), were numerous, and Cyanobacteria were present in low numbers. Archaea (less than 8% of the total community of each tested spring) belonged to Bathyarchaeota, Aigarchaeota, and Thaumarchaeota. The geographical location and the predominantly autotrophic microbial community, built on mechanisms other than the sulfur cycle-based ones, make CHS a special and unique terrestrial geothermal ecosystem.
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Finke N, Simister RL, O'Neil AH, Nomosatryo S, Henny C, MacLean LC, Canfield DE, Konhauser K, Lalonde SV, Fowle DA, Crowe SA. Mesophilic microorganisms build terrestrial mats analogous to Precambrian microbial jungles. Nat Commun 2019; 10:4323. [PMID: 31541087 PMCID: PMC6754388 DOI: 10.1038/s41467-019-11541-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 07/03/2019] [Indexed: 12/02/2022] Open
Abstract
Development of Archean paleosols and patterns of Precambrian rock weathering suggest colonization of continents by subaerial microbial mats long before evolution of land plants in the Phanerozoic Eon. Modern analogues for such mats, however, have not been reported, and possible biogeochemical roles of these mats in the past remain largely conceptual. We show that photosynthetic, subaerial microbial mats from Indonesia grow on mafic bedrocks at ambient temperatures and form distinct layers with features similar to Precambrian mats and paleosols. Such subaerial mats could have supported a substantial aerobic biosphere, including nitrification and methanotrophy, and promoted methane emissions and oxidative weathering under ostensibly anoxic Precambrian atmospheres. High C-turnover rates and cell abundances would have made these mats prime locations for early microbial diversification. Growth of landmass in the late Archean to early Proterozoic Eons could have reorganized biogeochemical cycles between land and sea impacting atmospheric chemistry and climate.
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Affiliation(s)
- N Finke
- Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
- Nordic center for earth evolution (NordCEE), University of Southern Denmark, Odense, Denmark
| | - R L Simister
- Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | | | - S Nomosatryo
- Research center for Limnology, Indonesian Institute of Sciences (LIPI), Jawa Barat, Indonesia
- GFZ German Research Centre for Geosciences, Potsdam, Germany
| | - C Henny
- Research center for Limnology, Indonesian Institute of Sciences (LIPI), Jawa Barat, Indonesia
| | | | - D E Canfield
- Nordic center for earth evolution (NordCEE), University of Southern Denmark, Odense, Denmark
| | - K Konhauser
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Canada
| | - S V Lalonde
- European Institute for Marine Studies, Technopôle Brest-Iroise, Plouzané, France
| | - D A Fowle
- Department of Geology, University of Kansas, Lawrence, KS, USA
| | - S A Crowe
- Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada.
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Mobberley JM, Lindemann SR, Bernstein HC, Moran JJ, Renslow RS, Babauta J, Hu D, Beyenal H, Nelson WC. Organismal and spatial partitioning of energy and macronutrient transformations within a hypersaline mat. FEMS Microbiol Ecol 2017; 93:3071443. [PMID: 28334407 PMCID: PMC5812542 DOI: 10.1093/femsec/fix028] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/13/2017] [Indexed: 02/06/2023] Open
Abstract
Phototrophic mat communities are model ecosystems for studying energy cycling and elemental transformations because complete biogeochemical cycles occur over millimeter-to-centimeter scales. Characterization of energy and nutrient capture within hypersaline phototrophic mats has focused on specific processes and organisms; however, little is known about community-wide distribution of and linkages between these processes. To investigate energy and macronutrient capture and flow through a structured community, the spatial and organismal distribution of metabolic functions within a compact hypersaline mat community from Hot Lake have been broadly elucidated through species-resolved metagenomics and geochemical, microbial diversity and metabolic gradient measurements. Draft reconstructed genomes of 34 abundant organisms revealed three dominant cyanobacterial populations differentially distributed across the top layers of the mat suggesting niche separation along light and oxygen gradients. Many organisms contained diverse functional profiles, allowing for metabolic response to changing conditions within the mat. Organisms with partial nitrogen and sulfur metabolisms were widespread indicating dependence on metabolite exchange. In addition, changes in community spatial structure were observed over the diel. These results indicate that organisms within the mat community have adapted to the temporally dynamic environmental gradients in this hypersaline mat through metabolic flexibility and fluid syntrophic interactions, including shifts in spatial arrangements.
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Affiliation(s)
- Jennifer M Mobberley
- Biological Science Division, Earth and Environmental Science Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Stephen R Lindemann
- Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West Lafayette, IN 47907, USA.,Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Hans C Bernstein
- Biological Science Division, Earth and Environmental Science Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.,The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
| | - James J Moran
- Chemical and Biological Signature Sciences, National Security Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Ryan S Renslow
- Biological Science Division, Earth and Environmental Science Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.,The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
| | - Jerome Babauta
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
| | - Dehong Hu
- Environmental Molecular Sciences Laboratory, Earth and Environmental Science Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Haluk Beyenal
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
| | - William C Nelson
- Biological Science Division, Earth and Environmental Science Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
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Nowicka B, Kruk J. Powered by light: Phototrophy and photosynthesis in prokaryotes and its evolution. Microbiol Res 2016; 186-187:99-118. [PMID: 27242148 DOI: 10.1016/j.micres.2016.04.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 02/12/2016] [Accepted: 04/01/2016] [Indexed: 11/29/2022]
Abstract
Photosynthesis is a complex metabolic process enabling photosynthetic organisms to use solar energy for the reduction of carbon dioxide into biomass. This ancient pathway has revolutionized life on Earth. The most important event was the development of oxygenic photosynthesis. It had a tremendous impact on the Earth's geochemistry and the evolution of living beings, as the rise of atmospheric molecular oxygen enabled the development of a highly efficient aerobic metabolism, which later led to the evolution of complex multicellular organisms. The mechanism of photosynthesis has been the subject of intensive research and a great body of data has been accumulated. However, the evolution of this process is not fully understood, and the development of photosynthesis in prokaryota in particular remains an unresolved question. This review is devoted to the occurrence and main features of phototrophy and photosynthesis in prokaryotes. Hypotheses concerning the origin and spread of photosynthetic traits in bacteria are also discussed.
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Affiliation(s)
- Beatrycze Nowicka
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
| | - Jerzy Kruk
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
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Houghton J, Fike D, Druschel G, Orphan V, Hoehler TM, Des Marais DJ. Spatial variability in photosynthetic and heterotrophic activity drives localized δ13C org fluctuations and carbonate precipitation in hypersaline microbial mats. GEOBIOLOGY 2014; 12:557-574. [PMID: 25312537 DOI: 10.1111/gbi.12113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 08/30/2014] [Indexed: 06/04/2023]
Abstract
Modern laminated photosynthetic microbial mats are ideal environments to study how microbial activity creates and modifies carbon and sulfur isotopic signatures prior to lithification. Laminated microbial mats from a hypersaline lagoon (Guerrero Negro, Baja California, Mexico) maintained in a flume in a greenhouse at NASA Ames Research Center were sampled for δ(13) C of organic material and carbonate to assess the impact of carbon fixation (e.g., photosynthesis) and decomposition (e.g., bacterial respiration) on δ(13) C signatures. In the photic zone, the δ(13) C org signature records a complex relationship between the activities of cyanobacteria under variable conditions of CO2 limitation with a significant contribution from green sulfur bacteria using the reductive TCA cycle for carbon fixation. Carbonate is present in some layers of the mat, associated with high concentrations of bacteriochlorophyll e (characteristic of green sulfur bacteria) and exhibits δ(13) C signatures similar to DIC in the overlying water column (-2.0‰), with small but variable decreases consistent with localized heterotrophic activity from sulfate-reducing bacteria (SRB). Model results indicate respiration rates in the upper 12 mm of the mat alter in situ pH and HCO3- concentrations to create both phototrophic CO2 limitation and carbonate supersaturation, leading to local precipitation of carbonate minerals. The measured activity of SRB with depth suggests they variably contribute to decomposition in the mat dependent on organic substrate concentrations. Millimeter-scale variability in the δ(13) C org signature beneath the photic zone in the mat is a result of shifting dominance between cyanobacteria and green sulfur bacteria with the aggregate signature overprinted by heterotrophic reworking by SRB and methanogens. These observations highlight the impact of sedimentary microbial processes on δ(13) C org signatures; these processes need to be considered when attempting to relate observed isotopic signatures in ancient sedimentary strata to conditions in the overlying water column at the time of deposition and associated inferences about carbon cycling.
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Affiliation(s)
- J Houghton
- Department of Earth and Planetary Sciences, Washington University, St. Louis, MO, USA
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Lee JZ, Burow LC, Woebken D, Everroad RC, Kubo MD, Spormann AM, Weber PK, Pett-Ridge J, Bebout BM, Hoehler TM. Fermentation couples Chloroflexi and sulfate-reducing bacteria to Cyanobacteria in hypersaline microbial mats. Front Microbiol 2014; 5:61. [PMID: 24616716 PMCID: PMC3935151 DOI: 10.3389/fmicb.2014.00061] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 01/30/2014] [Indexed: 11/17/2022] Open
Abstract
Past studies of hydrogen cycling in hypersaline microbial mats have shown an active nighttime cycle, with production largely from Cyanobacteria and consumption from sulfate-reducing bacteria (SRB). However, the mechanisms and magnitude of hydrogen cycling have not been extensively studied. Two mats types near Guerrero Negro, Mexico-permanently submerged Microcoleus microbial mat (GN-S), and intertidal Lyngbya microbial mat (GN-I)-were used in microcosm diel manipulation experiments with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), molybdate, ammonium addition, and physical disruption to understand the processes responsible for hydrogen cycling between mat microbes. Across microcosms, H2 production occurred under dark anoxic conditions with simultaneous production of a suite of organic acids. H2 production was not significantly affected by inhibition of nitrogen fixation, but rather appears to result from constitutive fermentation of photosynthetic storage products by oxygenic phototrophs. Comparison to accumulated glycogen and to CO2 flux indicated that, in the GN-I mat, fermentation released almost all of the carbon fixed via photosynthesis during the preceding day, primarily as organic acids. Across mats, although oxygenic and anoxygenic phototrophs were detected, cyanobacterial [NiFe]-hydrogenase transcripts predominated. Molybdate inhibition experiments indicated that SRBs from a wide distribution of DsrA phylotypes were responsible for H2 consumption. Incubation with (13)C-acetate and NanoSIMS (secondary ion mass-spectrometry) indicated higher uptake in both Chloroflexi and SRBs relative to other filamentous bacteria. These manipulations and diel incubations confirm that Cyanobacteria were the main fermenters in Guerrero Negro mats and that the net flux of nighttime fermentation byproducts (not only hydrogen) was largely regulated by the interplay between Cyanobacteria, SRBs, and Chloroflexi.
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Affiliation(s)
- Jackson Z. Lee
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
- Bay Area Environmental Research InstituteSonoma, CA, USA
| | - Luke C. Burow
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
- Departments of Civil and Environmental Engineering, and Chemical Engineering, Stanford UniversityStanford, CA, USA
| | - Dagmar Woebken
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
- Departments of Civil and Environmental Engineering, and Chemical Engineering, Stanford UniversityStanford, CA, USA
| | | | - Mike D. Kubo
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
- The SETI InstituteMountain View, CA, USA
| | - Alfred M. Spormann
- Departments of Civil and Environmental Engineering, and Chemical Engineering, Stanford UniversityStanford, CA, USA
| | - Peter K. Weber
- Lawrence Livermore National Lab, Chemical Sciences DivisionLivermore, CA, USA
| | - Jennifer Pett-Ridge
- Lawrence Livermore National Lab, Chemical Sciences DivisionLivermore, CA, USA
| | - Brad M. Bebout
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
| | - Tori M. Hoehler
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
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Control of temperature on microbial community structure in hot springs of the Tibetan Plateau. PLoS One 2013; 8:e62901. [PMID: 23667538 PMCID: PMC3647046 DOI: 10.1371/journal.pone.0062901] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 03/26/2013] [Indexed: 11/24/2022] Open
Abstract
The Tibetan Plateau in Northwest China hosts a number of hot springs that represent a biodiversity hotspot for thermophiles, yet their diversity and relationship to environmental conditions are poorly explored in these habitats. In this study we investigated microbial diversity and community composition in 13 Tibetan hot springs with a wide range of temperatures (22.1–75°C) and other geochemical conditions by using the 16S rRNA gene pyrosequencing approach. Bacteria (108–1011 copy/g; 42 bacterial phyla) in Tibetan hot springs were more abundant and far more diverse than Archaea (107–1010 copy/g; 5 archaeal phyla). The dominant bacterial phyla systematically varied with temperature. Moderate temperatures (75–66°C) favored Aquificae, GAL35, and novel Bacteria, whereas low temperatures (60–22.1°C) selected for Deinococcus-Thermus, Cyanobacteria, and Chloroflexi. The relative abundance of Aquificae was correlated positively with temperature, but the abundances of Deinococcus-Thermus, Cyanobacteria, and Chloroflexi were negatively correlated with temperature. Cyanobacteria and Chloroflexi were abundant in Tibetan hot springs and their abundances were positively correlated at low temperatures (55–43°C) but negatively correlated at moderate temperatures (75–55°C). These correlation patterns suggest a complex physiological relationship between these two phyla. Most archaeal sequences were related to Crenarchaeota with only a few related to Euryarchaeota and Thaumarchaeota. Despite the fact that microbial composition in Tibetan hot springs was strongly shaped by temperature, microbial diversity (richness, evenness and Shannon diversity) was not significantly correlated with temperature change. The results of this study expand our current understanding of microbial ecology in Tibetan hot springs and provide a basis for a global comparison.
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