1
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Géron A, Werner J, Wattiez R, Matallana-Surget S. Towards the discovery of novel molecular clocks in Prokaryotes. Crit Rev Microbiol 2024; 50:491-503. [PMID: 37330701 DOI: 10.1080/1040841x.2023.2220789] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 01/17/2023] [Accepted: 02/15/2023] [Indexed: 06/19/2023]
Abstract
Diel cycle is of enormous biological importance as it imposes daily oscillation in environmental conditions, which temporally structures most ecosystems. Organisms developed biological time-keeping mechanisms - circadian clocks - that provide a significant fitness advantage over competitors by optimising the synchronisation of their biological activities. While circadian clocks are ubiquitous in Eukaryotes, they are so far only characterised in Cyanobacteria within Prokaryotes. However, growing evidence suggests that circadian clocks are widespread in the bacterial and archaeal domains. As Prokaryotes are at the heart of crucial environmental processes and are essential to human health, unravelling their time-keeping systems provides numerous applications in medical research, environmental sciences, and biotechnology. In this review, we elaborate on how novel circadian clocks in Prokaryotes offer research and development perspectives. We compare and contrast the different circadian systems in Cyanobacteria and discuss about their evolution and taxonomic distribution. We necessarily provide an updated phylogenetic analysis of bacterial and archaeal species that harbour homologs of the main cyanobacterial clock components. Finally, we elaborate on new potential clock-controlled microorganisms that represent opportunities of ecological and industrial relevance in prokaryotic groups such as anoxygenic photosynthetic bacteria, methanogenic archaea, methanotrophs or sulphate-reducing bacteria.
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Affiliation(s)
- Augustin Géron
- Division of Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, UK
- Proteomic and Microbiology Department, University of Mons, Mons, Belgium
| | - Johannes Werner
- High Performance and Cloud Computing Group, Zentrum für Datenverarbeitung (ZDV), University of Tübingen, Tübingen, Germany
| | - Ruddy Wattiez
- Proteomic and Microbiology Department, University of Mons, Mons, Belgium
| | - Sabine Matallana-Surget
- Division of Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, UK
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2
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Singh VK, Jha S, Rana P, Mishra S, Kumari N, Singh SC, Anand S, Upadhye V, Sinha RP. Resilience and Mitigation Strategies of Cyanobacteria under Ultraviolet Radiation Stress. Int J Mol Sci 2023; 24:12381. [PMID: 37569755 PMCID: PMC10419127 DOI: 10.3390/ijms241512381] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/31/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
Ultraviolet radiation (UVR) tends to damage key cellular machinery. Cells may adapt by developing several defence mechanisms as a response to such damage; otherwise, their destiny is cell death. Since cyanobacteria are primary biotic components and also important biomass producers, any drastic effects caused by UVR may imbalance the entire ecosystem. Cyanobacteria are exposed to UVR in their natural habitats. This exposure can cause oxidative stress which affects cellular morphology and vital processes such as cell growth and differentiation, pigmentation, photosynthesis, nitrogen metabolism, and enzyme activity, as well as alterations in the native structure of biomolecules such as proteins and DNA. The high resilience and several mitigation strategies adopted by a cyanobacterial community in the face of UV stress are attributed to the activation of several photo/dark repair mechanisms, avoidance, scavenging, screening, antioxidant systems, and the biosynthesis of UV photoprotectants, such as mycosporine-like amino acids (MAAs), scytonemin (Scy), carotenoids, and polyamines. This knowledge can be used to develop new strategies for protecting other organisms from the harmful effects of UVR. The review critically reports the latest updates on various resilience and defence mechanisms employed by cyanobacteria to withstand UV-stressed environments. In addition, recent developments in the field of the molecular biology of UV-absorbing compounds such as mycosporine-like amino acids and scytonemin and the possible role of programmed cell death, signal perception, and transduction under UVR stress are discussed.
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Affiliation(s)
- Varsha K. Singh
- Laboratory of Photobiology and Molecular Microbiology, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India; (V.K.S.); (S.J.); (P.R.); (S.M.); (N.K.)
| | - Sapana Jha
- Laboratory of Photobiology and Molecular Microbiology, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India; (V.K.S.); (S.J.); (P.R.); (S.M.); (N.K.)
| | - Palak Rana
- Laboratory of Photobiology and Molecular Microbiology, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India; (V.K.S.); (S.J.); (P.R.); (S.M.); (N.K.)
| | - Sonal Mishra
- Laboratory of Photobiology and Molecular Microbiology, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India; (V.K.S.); (S.J.); (P.R.); (S.M.); (N.K.)
| | - Neha Kumari
- Laboratory of Photobiology and Molecular Microbiology, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India; (V.K.S.); (S.J.); (P.R.); (S.M.); (N.K.)
| | - Suresh C. Singh
- Taurmed Technologies Pvt Ltd., 304, Pearl’s Business Park, Netaji Subhash Place, New Delhi 110034, India; (S.C.S.); (S.A.)
| | - Shekhar Anand
- Taurmed Technologies Pvt Ltd., 304, Pearl’s Business Park, Netaji Subhash Place, New Delhi 110034, India; (S.C.S.); (S.A.)
| | - Vijay Upadhye
- Department of Microbiology, Parul Institute of Applied Science, Center of Research for Development, Parul University, Vadodara 391760, India;
| | - Rajeshwar P. Sinha
- Laboratory of Photobiology and Molecular Microbiology, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India; (V.K.S.); (S.J.); (P.R.); (S.M.); (N.K.)
- University Center for Research & Development (UCRD), Chandigarh University, Chandigarh 140413, India
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3
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Moran JJ, Bernstein HC, Mobberley JM, Thompson AM, Kim YM, Dana KL, Cory AB, Courtney S, Renslow RS, Fredrickson JK, Kreuzer HW, Lipton MS. Daylight-driven carbon exchange through a vertically structured microbial community. Front Microbiol 2023; 14:1139213. [PMID: 37303779 PMCID: PMC10251406 DOI: 10.3389/fmicb.2023.1139213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Interactions between autotrophs and heterotrophs are central to carbon (C) exchange across trophic levels in essentially all ecosystems and metabolite exchange is a frequent mechanism for distributing C within spatially structured ecosystems. Yet, despite the importance of C exchange, the timescales at which fixed C is transferred in microbial communities is poorly understood. We employed a stable isotope tracer combined with spatially resolved isotope analysis to quantify photoautotrophic uptake of bicarbonate and track subsequent exchanges across a vertical depth gradient in a stratified microbial mat over a light-driven diel cycle. We observed that C mobility, both across the vertical strata and between taxa, was highest during periods of active photoautotrophy. Parallel experiments with 13C-labeled organic substrates (acetate and glucose) showed comparably less exchange of C within the mat. Metabolite analysis showed rapid incorporation of 13C into molecules that can both comprise a portion of the extracellular polymeric substances in the system and serve to transport C between photoautotrophs and heterotrophs. Stable isotope proteomic analysis revealed rapid C exchange between cyanobacterial and associated heterotrophic community members during the day with decreased exchange at night. We observed strong diel control on the spatial exchange of freshly fixed C within tightly interacting mat communities suggesting a rapid redistribution, both spatially and taxonomically, primarily during daylight periods.
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Affiliation(s)
- James J. Moran
- Pacific Northwest National Laboratory, Richland, WA, United States
- Department of Integrative Biology, Michigan State University, East Lansing, MI, United States
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI, United States
| | - Hans C. Bernstein
- Pacific Northwest National Laboratory, Richland, WA, United States
- Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
- ARC – The Arctic Centre for Sustainable Energy, UiT The Arctic University of Norway, Tromsø, Norway
| | | | | | - Young-Mo Kim
- Pacific Northwest National Laboratory, Richland, WA, United States
| | - Karl L. Dana
- Pacific Northwest National Laboratory, Richland, WA, United States
| | | | - Steph Courtney
- Pacific Northwest National Laboratory, Richland, WA, United States
| | - Ryan S. Renslow
- Pacific Northwest National Laboratory, Richland, WA, United States
| | | | - Helen W. Kreuzer
- Pacific Northwest National Laboratory, Richland, WA, United States
| | - Mary S. Lipton
- Pacific Northwest National Laboratory, Richland, WA, United States
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4
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Exploring the Relationship between Biosynthetic Gene Clusters and Constitutive Production of Mycosporine-like Amino Acids in Brazilian Cyanobacteria. Molecules 2023; 28:molecules28031420. [PMID: 36771087 PMCID: PMC9918943 DOI: 10.3390/molecules28031420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/12/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
Cyanobacteria are oxygenic phototrophic prokaryotes that have evolved to produce ultraviolet-screening mycosporine-like amino acids (MAAs) to lessen harmful effects from obligatory exposure to solar UV radiation. The cyanobacterial MAA biosynthetic cluster is formed by a gene encoding 2-epi-5-epi-valiolone synthase (EVS) located immediately upstream from an O-methyltransferase (OMT) encoding gene, which together biosynthesize the expected MAA precursor 4-deoxygadusol. Accordingly, these genes are typically absent in non-producers. In this study, the relationship between gene cluster architecture and constitutive production of MAAs was evaluated in cyanobacteria isolated from various Brazilian biomes. Constitutive production of MAAs was only detected in strains where genes formed a co-linear cluster. Expectedly, this production was enhanced upon exposure of the strains to UV irradiance and by using distinct culture media. Constitutive production of MAAs was not detected in all other strains and, unexpectedly, production could not be induced by exposure to UV irradiation or changing growth media. Other photoprotection strategies which might be employed by these MAA non-producing strains are discussed. The evolutionary and ecological significance of gene order conservation warrants closer experimentation, which may provide a first insight into regulatory interactions of genes encoding enzymes for MAA biosynthesis.
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Zhao M, Zhao Y, Lin W, Xiao KQ. An overview of experimental simulations of microbial activity in early Earth. Front Microbiol 2022; 13:1052831. [PMID: 36713221 PMCID: PMC9878457 DOI: 10.3389/fmicb.2022.1052831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 12/16/2022] [Indexed: 01/15/2023] Open
Abstract
Microbial activity has shaped the evolution of the ocean and atmosphere throughout the Earth history. Thus, experimental simulations of microbial metabolism under the environment conditions of the early Earth can provide vital information regarding biogeochemical cycles and the interaction and coevolution between life and environment, with important implications for extraterrestrial exploration. In this review, we discuss the current scope and knowledge of experimental simulations of microbial activity in environments representative of those of early Earth, with perspectives on future studies. Inclusive experimental simulations involving multiple species, and cultivation experiments with more constraints on environmental conditions similar to early Earth would significantly advance our understanding of the biogeochemical cycles of the geological past.
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Affiliation(s)
- Mingyu Zhao
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Yao Zhao
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China
| | - Wei Lin
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Ke-Qing Xiao
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
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6
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Paul V, Banerjee Y, Ghosh P, Busi SB. Depthwise microbiome and isotopic profiling of a moderately saline microbial mat in a solar saltern. Sci Rep 2020; 10:20686. [PMID: 33244085 PMCID: PMC7693307 DOI: 10.1038/s41598-020-77622-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 11/09/2020] [Indexed: 11/23/2022] Open
Abstract
The solar salterns in Tuticorin, India, are man-made, saline to hypersaline systems hosting some uniquely adapted populations of microorganisms and eukaryotic algae that have not been fully characterized. Two visually different microbial mats (termed 'white' and 'green') developing on the reservoir ponds (53 PSU) were isolated from the salterns. Firstly, archaeal and bacterial diversity in different vertical layers of the mats were analyzed. Culture-independent 16S rRNA gene analysis revealed that both bacteria and archaea were rich in their diversity. The top layers had a higher representation of halophilic archaea Halobacteriaceae, phylum Chloroflexi, and classes Anaerolineae, Delta- and Gamma- Proteobacteria than the deeper sections, indicating that a salinity gradient exists within the mats. Limited presence of Cyanobacteria and detection of algae-associated bacteria, such as Phycisphaerae, Phaeodactylibacter and Oceanicaulis likely implied that eukaryotic algae and other phototrophs could be the primary producers within the mat ecosystem. Secondly, predictive metabolic pathway analysis using the 16S rRNA gene data revealed that in addition to the regulatory microbial functions, methane and nitrogen metabolisms were prevalent. Finally, stable carbon and nitrogen isotopic compositions determined from both mat samples showed that the δ13Corg and δ15Norg values increased slightly with depth, ranging from - 16.42 to - 14.73‰, and 11.17 to 13.55‰, respectively. The isotopic signature along the microbial mat profile followed a pattern that is distinctive to the community composition and net metabolic activities, and comparable to saline mats in other salterns. The results and discussions presented here by merging culture-independent studies, predictive metabolic analyses and isotopic characterization, provide a collective strategy to understand the compositional and functional characteristics of microbial mats in saline environments.
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Affiliation(s)
- Varun Paul
- Department of Geosciences, Mississippi State University, Starkville, MS, 39762, USA.
| | - Yogaraj Banerjee
- Interdisciplinary Centre for Water Research, Indian Institute of Science, Bangalore, 560012, India
| | - Prosenjit Ghosh
- Interdisciplinary Centre for Water Research, Indian Institute of Science, Bangalore, 560012, India
- Centre for Earth Sciences, Indian Institute of Science, Bangalore, 560012, India
| | - Susheel Bhanu Busi
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 4362, Esch-sur-Alzette, Luxembourg
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7
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Conradi FD, Mullineaux CW, Wilde A. The Role of the Cyanobacterial Type IV Pilus Machinery in Finding and Maintaining a Favourable Environment. Life (Basel) 2020; 10:life10110252. [PMID: 33114175 PMCID: PMC7690835 DOI: 10.3390/life10110252] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/18/2020] [Accepted: 10/21/2020] [Indexed: 12/11/2022] Open
Abstract
Type IV pili (T4P) are proteinaceous filaments found on the cell surface of many prokaryotic organisms and convey twitching motility through their extension/retraction cycles, moving cells across surfaces. In cyanobacteria, twitching motility is the sole mode of motility properly characterised to date and is the means by which cells perform phototaxis, the movement towards and away from directional light sources. The wavelength and intensity of the light source determine the direction of movement and, sometimes in concert with nutrient conditions, act as signals for some cyanobacteria to form mucoid multicellular assemblages. Formation of such aggregates or flocs represents an acclimation strategy to unfavourable environmental conditions and stresses, such as harmful light conditions or predation. T4P are also involved in natural transformation by exogenous DNA, secretion processes, and in cellular adaptation and survival strategies, further cementing the role of cell surface appendages. In this way, cyanobacteria are finely tuned by external stimuli to either escape unfavourable environmental conditions via phototaxis, exchange genetic material, and to modify their surroundings to fit their needs by forming multicellular assemblies.
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Affiliation(s)
- Fabian D. Conradi
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (F.D.C.); (C.W.M.)
| | - Conrad W. Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (F.D.C.); (C.W.M.)
| | - Annegret Wilde
- Institute of Biology III, University of Freiburg, Schänzlestr. 1, 79104 Freiburg; Germany
- Correspondence:
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8
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Hirano M, Takebe M, Ishido T, Ide T, Matsunaga S. The C-terminal region affects the activity of photoactivated adenylyl cyclase from Oscillatoria acuminata. Sci Rep 2019; 9:20262. [PMID: 31889099 PMCID: PMC6937261 DOI: 10.1038/s41598-019-56721-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 12/13/2019] [Indexed: 11/09/2022] Open
Abstract
Photoactivated adenylyl cyclase (PAC) is a unique protein that, upon blue light exposure, catalyzes cAMP production. The crystal structures of two PACs, from Oscillatoria acuminata (OaPAC) and Beggiatoa sp. (bPAC), have been solved, and they show a high degree of similarity. However, the photoactivity of OaPAC is much lower than that of bPAC, and the regulatory mechanism of PAC photoactivity, which induces the difference in activity between OaPAC and bPAC, has not yet been clarified. Here, we investigated the role of the C-terminal region in OaPAC, the length of which is the only notable difference from bPAC. We found that the photoactivity of OaPAC was inversely proportional to the C-terminal length. However, the deletion of more than nine amino acids did not further increase the activity, indicating that the nine amino acids at the C-terminal critically affect the photoactivity. Besides, absorption spectral features of light-sensing domains (BLUF domains) of the C-terminal deletion mutants showed similar light-dependent spectral shifts as in WT, indicating that the C-terminal region influences the activity without interacting with the BLUF domain. The study characterizes new PAC mutants with modified photoactivities, which could be useful as optogenetics tools.
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Affiliation(s)
- Minako Hirano
- Bio Photonics Laboratory, The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsu Nishi-ku, Hamamatsu, Shizuoka, 431-1202, Japan.
| | - Masumi Takebe
- Central Research Laboratory, Hamamatsu Photonics K.K., 5000 Hirakuchi Hamakita-ku, Hamamatsu, Shizuoka, 434-8601, Japan
| | - Tomoya Ishido
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama-shi, Okayama, 700-8530, Japan
| | - Toru Ide
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama-shi, Okayama, 700-8530, Japan
| | - Shigeru Matsunaga
- Central Research Laboratory, Hamamatsu Photonics K.K., 5000 Hirakuchi Hamakita-ku, Hamamatsu, Shizuoka, 434-8601, Japan.
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9
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Haro S, Brodersen KE, Bohórquez J, Papaspyrou S, Corzo A, Kühl M. Radiative Energy Budgets in a Microbial Mat Under Different Irradiance and Tidal Conditions. MICROBIAL ECOLOGY 2019; 77:852-865. [PMID: 30852639 DOI: 10.1007/s00248-019-01350-6] [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: 10/29/2018] [Accepted: 02/19/2019] [Indexed: 06/09/2023]
Abstract
Irradiance and temperature variations during tidal cycles modulate microphytobenthic primary production potentially by changing the radiative energy balance of photosynthetic mats between immersion and emersion and thus sediment daily net metabolism. To test the effect of tidal stages on the radiative energy budget, we used microsensor measurements of oxygen, temperature, and scalar irradiance to estimate the radiative energy budget in a coastal photosynthetic microbial mat during immersion (constant water column of 2 cm) and emersion under increasing irradiance. Total absorbed light energy was higher in immersion than emersion, due to a lower reflectance of the microbial mat, while most (> 97%) of the absorbed light energy was dissipated as heat irrespective of tidal conditions. During immersion, the upward heat flux was higher than the downward one, whereas the opposite occurred during emersion. At highest photon irradiance (800 μmol photon m-2 s-1), the sediment temperature increased ~ 2.5 °C after changing the conditions from immersion to emersion. The radiative energy balance showed that less than 1% of the incident light energy (PAR, 400-700 nm) was conserved by photosynthesis under both tidal conditions. At low to moderate incident irradiances, the light use efficiency was similar during the tidal stages. In contrast, we found an ~ 30% reduction in the light use efficiency during emersion as compared to immersion under the highest irradiance likely due to the rapid warming of the sediment during emersion and increased non-photochemical quenching. These changes in the photosynthetic efficiency and radiative energy budget could affect both primary producers and temperature-dependent bacterial activity and consequently daily net metabolism rates having important ecological consequences.
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Affiliation(s)
- S Haro
- Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, 11510, Puerto Real, Cádiz, Spain.
- University Institute of Marine Research (INMAR), University of Cádiz, Cadiz, Spain.
| | - K E Brodersen
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - J Bohórquez
- Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, 11510, Puerto Real, Cádiz, Spain
- University Institute of Marine Research (INMAR), University of Cádiz, Cadiz, Spain
| | - S Papaspyrou
- Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, 11510, Puerto Real, Cádiz, Spain
- University Institute of Marine Research (INMAR), University of Cádiz, Cadiz, Spain
| | - A Corzo
- Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, 11510, Puerto Real, Cádiz, Spain
- University Institute of Marine Research (INMAR), University of Cádiz, Cadiz, Spain
| | - M Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia
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10
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D'Agostino PM, Woodhouse JN, Liew HT, Sehnal L, Pickford R, Wong HL, Burns BP, Neilan BA. Bioinformatic, phylogenetic and chemical analysis of the UV‐absorbing compounds scytonemin and mycosporine‐like amino acids from the microbial mat communities of Shark Bay, Australia. Environ Microbiol 2019; 21:702-715. [DOI: 10.1111/1462-2920.14517] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 12/20/2018] [Accepted: 12/24/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Paul M. D'Agostino
- School of Biotechnology and Biomolecular Sciences University of New South Wales Sydney New South Wales Australia
- Biosystems Chemistry, Department of Chemistry and Center for Integrated Protein Science Munich (CIPSM) Technische Universität München Garching Germany
| | - Jason N. Woodhouse
- School of Biotechnology and Biomolecular Sciences University of New South Wales Sydney New South Wales Australia
- Department of Experimental Limnology Leibniz‐Institute of Freshwater Ecology and Inland Fisheries Stechlin Germany
| | - Heng Tai Liew
- School of Biotechnology and Biomolecular Sciences University of New South Wales Sydney New South Wales Australia
- School of Biological Sciences Nanyang Technological University 60 Nanyang Drive Singapore
| | - Luděk Sehnal
- Research Centre for Toxic Compounds in the Environment, Faculty of Science Masaryk University Kamenice 5, 625 00, Brno Czech Republic
| | - Russel Pickford
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre University of New South Wales Sydney New South Wales Australia
| | - Hon Lun Wong
- School of Biotechnology and Biomolecular Sciences University of New South Wales Sydney New South Wales Australia
| | - Brendan P. Burns
- School of Biotechnology and Biomolecular Sciences University of New South Wales Sydney New South Wales Australia
| | - Brett A. Neilan
- School of Biotechnology and Biomolecular Sciences University of New South Wales Sydney New South Wales Australia
- School of Environmental and Life Sciences University of Newcastle Newcastle New South Wales Australia
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11
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Köbler C, Schultz SJ, Kopp D, Voigt K, Wilde A. The role of the Synechocystis sp. PCC 6803 homolog of the circadian clock output regulator RpaA in day-night transitions. Mol Microbiol 2018; 110:847-861. [PMID: 30216574 DOI: 10.1111/mmi.14129] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 09/07/2018] [Accepted: 07/12/2018] [Indexed: 01/20/2023]
Abstract
Cyanobacteria exhibit rhythmic gene expression with a period length of 24 hours to adapt to daily environmental changes. In the model organism Synechococcuselongatus PCC 7942, the central oscillator consists of the three proteins KaiA, KaiB and KaiC and utilizes the histidine kinase SasA and its response regulator RpaA as output-signaling pathway. Synechocystis sp. PCC 6803 contains in addition to the canonical kaiAB1C1 gene cluster two further homologs of the kaiB and kaiC genes. Here, we demonstrate that the SasA-RpaA system interacts with the KaiAB1C1 core oscillator only. Interaction with KaiC2 and KaiC3 proteins was not detected, suggesting different signal transduction components for the clock homologs. Inactivation of rpaA in Synechocystis sp. PCC 6803 leads to reduced viability of the mutant in light-dark cycles, especially under mixotrophic growth conditions. Chemoheterotrophic growth of the ∆rpaA strain in the dark was abolished completely. Transcriptomic data revealed that RpaA is mainly involved in the regulation of genes related to CO2 - acclimation in the light and to carbon metabolism in the dark. Further, our results indicate a link between the circadian clock and phototaxis.
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Affiliation(s)
- Christin Köbler
- Faculty of Biology, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany
| | - Siri-Jasmin Schultz
- Faculty of Biology, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany
| | - Dominik Kopp
- Faculty of Biology, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany
| | - Karsten Voigt
- Faculty of Biology, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany
| | - Annegret Wilde
- Faculty of Biology, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany.,BIOSS Centre of Biological Signalling Studies, University of Freiburg, 79106, Freiburg, Germany
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12
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Mloszewska AM, Cole DB, Planavsky NJ, Kappler A, Whitford DS, Owttrim GW, Konhauser KO. UV radiation limited the expansion of cyanobacteria in early marine photic environments. Nat Commun 2018; 9:3088. [PMID: 30082788 PMCID: PMC6079077 DOI: 10.1038/s41467-018-05520-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 07/09/2018] [Indexed: 01/09/2023] Open
Abstract
Prior to atmospheric oxygenation, ecosystems were exposed to higher UV radiation fluxes relative to modern surface environments. Iron–silica mineral coatings have been evoked as effective UV radiation shields in early terrestrial settings. Here we test whether similar protection applied to planktonic cyanobacteria within the Archean water column. Based on experiments done under Archean seawater conditions, we report that Fe(III)–Si-rich precipitates absorb up to 70% of incoming UV-C radiation, with a reduction of <20% in photosynthetically active radiation flux. However, we demonstrate that even short periods of UV-C irradiation in the presence of Fe(III)–Si precipitates resulted in high mortality rates, and suggest that these effects would have persisted throughout much of the photic zone. Our findings imply that despite the shielding properties of Fe(III)–Si-rich precipitates in the early water column, UV radiation would continue to limit cyanobacterial expansion and likely had a greater effect on Archean ecosystem structure before the formation of an ozone layer. The means by which planktonic cyanobacteria were able to persist through the Archean despite high fluxes of UV radiation are unclear. Here, the authors show that Fe(III)-Si rich precipitates in the Archean photic zone could have provided early planktonic cyanobacteria an effective shield against UV-C radiation.
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Affiliation(s)
- Aleksandra M Mloszewska
- Earth Sciences Department, University of Toronto, Toronto, M5S 3B1, ON, Canada. .,Applied Geosciences, University of Tübingen, Tübingen, 72074, Germany. .,Earth and Atmospheric Sciences, University of Alberta, Edmonton, T6G 2E3, AB, Canada.
| | - Devon B Cole
- Department of Geology and Geophysics, Yale University, New Haven, 06511, CT, USA
| | - Noah J Planavsky
- Department of Geology and Geophysics, Yale University, New Haven, 06511, CT, USA
| | - Andreas Kappler
- Applied Geosciences, University of Tübingen, Tübingen, 72074, Germany
| | - Denise S Whitford
- Biological Sciences, University of Alberta, Edmonton, T6G 2E9, AB, Canada
| | - George W Owttrim
- Biological Sciences, University of Alberta, Edmonton, T6G 2E9, AB, Canada
| | - Kurt O Konhauser
- Earth and Atmospheric Sciences, University of Alberta, Edmonton, T6G 2E3, AB, Canada.
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Sallstedt T, Bengtson S, Broman C, Crill PM, Canfield DE. Evidence of oxygenic phototrophy in ancient phosphatic stromatolites from the Paleoproterozoic Vindhyan and Aravalli Supergroups, India. GEOBIOLOGY 2018; 16:139-159. [PMID: 29380943 DOI: 10.1111/gbi.12274] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 12/17/2017] [Indexed: 05/24/2023]
Abstract
Fossil microbiotas are rare in the early rock record, limiting the type of ecological information extractable from ancient microbialites. In the absence of body fossils, emphasis may instead be given to microbially derived features, such as microbialite growth patterns, microbial mat morphologies, and the presence of fossilized gas bubbles in lithified mats. The metabolic affinity of micro-organisms associated with phosphatization may reveal important clues to the nature and accretion of apatite-rich microbialites. Stromatolites from the 1.6 Ga Chitrakoot Formation (Semri Group, Vindhyan Supergroup) in central India contain abundant fossilized bubbles interspersed within fine-grained in situ-precipitated apatite mats with average δ13 Corg indicative of carbon fixation by the Calvin cycle. In addition, the mats hold a synsedimentary fossil biota characteristic of cyanobacterial and rhodophyte morphotypes. Phosphatic oncoid cone-like stromatolites from the Paleoproterozoic Aravalli Supergroup (Jhamarkotra Formation) comprise abundant mineralized bubbles enmeshed within tufted filamentous mat fabrics. Construction of these tufts is considered to be the result of filamentous bacteria gliding within microbial mats, and as fossilized bubbles within pristine mat laminae can be used as a proxy for oxygenic phototrophy, this provides a strong indication for cyanobacterial activity in the Aravalli mounds. We suggest that the activity of oxygenic phototrophs may have been significant for the formation of apatite in both Vindhyan and Aravalli stromatolites, mainly by concentrating phosphate and creating steep diurnal redox gradients within mat pore spaces, promoting apatite precipitation. The presence in the Indian stromatolites of alternating apatite-carbonate lamina may result from local variations in pH and oxygen levels caused by photosynthesis-respiration in the mats. Altogether, this study presents new insights into the ecology of ancient phosphatic stromatolites and warrants further exploration into the role of oxygen-producing biotas in the formation of Paleoproterozoic shallow-basin phosphorites.
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Affiliation(s)
- T Sallstedt
- Department of Paleobiology, Swedish Museum of Natural History, Stockholm, Sweden
- Department of Biology, Nordic Center for Earth Evolution (NordCEE) and University of Southern Denmark, Odense, Denmark
| | - S Bengtson
- Department of Paleobiology, Swedish Museum of Natural History, Stockholm, Sweden
- Department of Biology, Nordic Center for Earth Evolution (NordCEE) and University of Southern Denmark, Odense, Denmark
| | - C Broman
- Department of Geological Sciences, Stockholm University, Stockholm, Sweden
| | - P M Crill
- Department of Geological Sciences, Stockholm University, Stockholm, Sweden
| | - D E Canfield
- Department of Biology, Nordic Center for Earth Evolution (NordCEE) and University of Southern Denmark, Odense, Denmark
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14
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Trampe E, Castenholz RW, Larsen JEN, Kühl M. Phototrophic microbes form endolithic biofilms in ikaite tufa columns (SW Greenland). Environ Microbiol 2017; 19:4754-4770. [DOI: 10.1111/1462-2920.13940] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 12/28/2022]
Affiliation(s)
- Erik Trampe
- Marine Biological Section; University of Copenhagen, Strandpromenaden 5; Helsingør DK-3000 Denmark
| | | | - Jens E. N. Larsen
- Marine Biological Section; University of Copenhagen, Strandpromenaden 5; Helsingør DK-3000 Denmark
| | - Michael Kühl
- Marine Biological Section; University of Copenhagen, Strandpromenaden 5; Helsingør DK-3000 Denmark
- Climate Change Cluster; University of Technology Sydney; Ultimo NSW 2007 Australia
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15
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Wilde A, Mullineaux CW. Light-controlled motility in prokaryotes and the problem of directional light perception. FEMS Microbiol Rev 2017; 41:900-922. [PMID: 29077840 PMCID: PMC5812497 DOI: 10.1093/femsre/fux045] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 09/12/2017] [Indexed: 12/02/2022] Open
Abstract
The natural light environment is important to many prokaryotes. Most obviously, phototrophic prokaryotes need to acclimate their photosynthetic apparatus to the prevailing light conditions, and such acclimation is frequently complemented by motility to enable cells to relocate in search of more favorable illumination conditions. Non-phototrophic prokaryotes may also seek to avoid light at damaging intensities and wavelengths, and many prokaryotes with diverse lifestyles could potentially exploit light signals as a rich source of information about their surroundings and a cue for acclimation and behavior. Here we discuss our current understanding of the ways in which bacteria can perceive the intensity, wavelength and direction of illumination, and the signal transduction networks that link light perception to the control of motile behavior. We discuss the problems of light perception at the prokaryotic scale, and the challenge of directional light perception in small bacterial cells. We explain the peculiarities and the common features of light-controlled motility systems in prokaryotes as diverse as cyanobacteria, purple photosynthetic bacteria, chemoheterotrophic bacteria and haloarchaea.
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Affiliation(s)
- Annegret Wilde
- Institute of Biology III, University of Freiburg, 79104 Freiburg, Germany
- BIOSS Centre of Biological Signalling Studies, University of Freiburg, 79106 Freiburg, Germany
| | - Conrad W. Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
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16
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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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17
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Pascal PY, Gros O, Boschker HT. Temporal fluctuations in the trophic role of large benthic sulfur bacteria in mangrove sediment. FOOD WEBS 2016. [DOI: 10.1016/j.fooweb.2016.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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18
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Oxidation of Molecular Hydrogen by a Chemolithoautotrophic Beggiatoa Strain. Appl Environ Microbiol 2016; 82:2527-36. [PMID: 26896131 PMCID: PMC4959497 DOI: 10.1128/aem.03818-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 02/10/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED A chemolithoautotrophic strain of the family Beggiatoaceae, Beggiatoa sp. strain 35Flor, was found to oxidize molecular hydrogen when grown in a medium with diffusional gradients of oxygen, sulfide, and hydrogen. Microsensor profiles and rate measurements suggested that the strain oxidized hydrogen aerobically when oxygen was available, while hydrogen consumption under anoxic conditions was presumably driven by sulfur respiration.Beggiatoa sp. 35Flor reached significantly higher biomass in hydrogen-supplemented oxygen-sulfide gradient media, but hydrogen did not support growth of the strain in the absence of reduced sulfur compounds. Nevertheless, hydrogen oxidation can provide Beggiatoa sp. 35Flor with energy for maintenance and assimilatory purposes and may support the disposal of internally stored sulfur to prevent physical damage resulting from excessive sulfur accumulation. Our knowledge about the exposure of natural populations of Beggiatoa ceae to hydrogen is very limited, but significant amounts of hydrogen could be provided by nitrogen fixation, fermentation, and geochemical processes in several of their typical habitats such as photosynthetic microbial mats and submarine sites of hydrothermal fluid flow. IMPORTANCE Reduced sulfur compounds are certainly the main electron donors for chemolithoautotrophic Beggiatoa ceae, but the traditional focus on this topic has left other possible inorganic electron donors largely unexplored. In this paper, we provide evidence that hydrogen oxidation has the potential to strengthen the ecophysiological plasticity of Beggiatoa ceaein several ways. Moreover, we show that hydrogen oxidation by members of this family can significantly influence biogeochemical gradients and therefore should be considered in environmental studies.
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19
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Chennu A, Grinham A, Polerecky L, de Beer D, Al-Najjar MAA. Rapid Reactivation of Cyanobacterial Photosynthesis and Migration upon Rehydration of Desiccated Marine Microbial Mats. Front Microbiol 2015; 6:1472. [PMID: 26733996 PMCID: PMC4689872 DOI: 10.3389/fmicb.2015.01472] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 12/07/2015] [Indexed: 01/24/2023] Open
Abstract
Desiccated cyanobacterial mats are the dominant biological feature in the Earth's arid zones. While the response of desiccated cyanobacteria to rehydration is well-documented for terrestrial systems, information about the response in marine systems is lacking. We used high temporal resolution hyperspectral imaging, liquid chromatography, pulse-amplitude fluorometry, oxygen microsensors, and confocal laser microscopy to study this response in a desiccated microbial mat from Exmouth Gulf, Australia. During the initial 15 min after rehydration chlorophyll a concentrations increased 2-5 fold and cyanobacterial photosynthesis was re-established. Although the mechanism behind this rapid increase of chlorophyll a remains unknown, we hypothesize that it involves resynthesis from a precursor stored in desiccated cyanobacteria. The subsequent phase (15 min-48 h) involved migration of the reactivated cyanobacteria toward the mat surface, which led, together with a gradual increase in chlorophyll a, to a further increase in photosynthesis. We conclude that the response involving an increase in chlorophyll a and recovery of photosynthetic activity within minutes after rehydration is common for cyanobacteria from desiccated mats of both terrestrial and marine origin. However, the response of upward migration and its triggering factor appear to be mat-specific and likely linked to other factors.
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Affiliation(s)
- Arjun Chennu
- Max Planck Institute for Marine MicrobiologyBremen, Germany
| | - Alistair Grinham
- School of Civil Engineering, The University of Queensland, St. LuciaQLD, Australia
| | - Lubos Polerecky
- Max Planck Institute for Marine MicrobiologyBremen, Germany
- Department of Earth Sciences, Utrecht UniversityUtrecht, Netherlands
| | - Dirk de Beer
- Max Planck Institute for Marine MicrobiologyBremen, Germany
| | - Mohammad A. A. Al-Najjar
- Max Planck Institute for Marine MicrobiologyBremen, Germany
- Red Sea Research Center, King Abdullah University of Science and TechnologyJeddah, Saudi Arabia
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20
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Wong HL, Smith DL, Visscher PT, Burns BP. Niche differentiation of bacterial communities at a millimeter scale in Shark Bay microbial mats. Sci Rep 2015; 5:15607. [PMID: 26499760 PMCID: PMC4620479 DOI: 10.1038/srep15607] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 09/28/2015] [Indexed: 02/01/2023] Open
Abstract
Modern microbial mats can provide key insights into early Earth ecosystems, and Shark Bay, Australia, holds one of the best examples of these systems. Identifying the spatial distribution of microorganisms with mat depth facilitates a greater understanding of specific niches and potentially novel microbial interactions. High throughput sequencing coupled with elemental analyses and biogeochemical measurements of two distinct mat types (smooth and pustular) at a millimeter scale were undertaken in the present study. A total of 8,263,982 16S rRNA gene sequences were obtained, which were affiliated to 58 bacterial and candidate phyla. The surface of both mats were dominated by Cyanobacteria, accompanied with known or putative members of Alphaproteobacteria and Bacteroidetes. The deeper anoxic layers of smooth mats were dominated by Chloroflexi, while Alphaproteobacteria dominated the lower layers of pustular mats. In situ microelectrode measurements revealed smooth mats have a steeper profile of O2 and H2S concentrations, as well as higher oxygen production, consumption, and sulfate reduction rates. Specific elements (Mo, Mg, Mn, Fe, V, P) could be correlated with specific mat types and putative phylogenetic groups. Models are proposed for these systems suggesting putative surface anoxic niches, differential nitrogen fixing niches, and those coupled with methane metabolism.
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Affiliation(s)
- Hon Lun Wong
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia
- Australian Centre for Astrobiology, University of New South Wales Sydney, Australia
| | - Daniela-Lee Smith
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia
- Australian Centre for Astrobiology, University of New South Wales Sydney, Australia
| | - Pieter T. Visscher
- Department of Marine Sciences, University of Connecticut, USA
- Australian Centre for Astrobiology, University of New South Wales Sydney, Australia
| | - Brendan P. Burns
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia
- Australian Centre for Astrobiology, University of New South Wales Sydney, Australia
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21
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Cyanobacterial reuse of extracellular organic carbon in microbial mats. ISME JOURNAL 2015; 10:1240-51. [PMID: 26495994 PMCID: PMC5029224 DOI: 10.1038/ismej.2015.180] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 08/21/2015] [Accepted: 09/02/2015] [Indexed: 11/09/2022]
Abstract
Cyanobacterial organic matter excretion is crucial to carbon cycling in many microbial communities, but the nature and bioavailability of this C depend on unknown physiological functions. Cyanobacteria-dominated hypersaline laminated mats are a useful model ecosystem for the study of C flow in complex communities, as they use photosynthesis to sustain a more or less closed system. Although such mats have a large C reservoir in the extracellular polymeric substances (EPSs), the production and degradation of organic carbon is not well defined. To identify extracellular processes in cyanobacterial mats, we examined mats collected from Elkhorn Slough (ES) at Monterey Bay, California, for glycosyl and protein composition of the EPS. We found a prevalence of simple glucose polysaccharides containing either α or β (1,4) linkages, indicating distinct sources of glucose with differing enzymatic accessibility. Using proteomics, we identified cyanobacterial extracellular enzymes, and also detected activities that indicate a capacity for EPS degradation. In a less complex system, we characterized the EPS of a cyanobacterial isolate from ES, ESFC-1, and found the extracellular composition of biofilms produced by this unicyanobacterial culture were similar to that of natural mats. By tracing isotopically labeled EPS into single cells of ESFC-1, we demonstrated rapid incorporation of extracellular-derived carbon. Taken together, these results indicate cyanobacteria reuse excess organic carbon, constituting a dynamic pool of extracellular resources in these mats.
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Biddanda BA, McMillan AC, Long SA, Snider MJ, Weinke AD. Seeking sunlight: rapid phototactic motility of filamentous mat-forming cyanobacteria optimize photosynthesis and enhance carbon burial in Lake Huron's submerged sinkholes. Front Microbiol 2015; 6:930. [PMID: 26441867 PMCID: PMC4561352 DOI: 10.3389/fmicb.2015.00930] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 08/24/2015] [Indexed: 11/13/2022] Open
Abstract
We studied the motility of filamentous mat-forming cyanobacteria consisting primarily of Oscillatoria-like cells growing under low-light, low-oxygen, and high-sulfur conditions in Lake Huron's submerged sinkholes using in situ observations, in vitro measurements and time-lapse microscopy. Gliding movement of the cyanobacterial trichomes (100-10,000 μm long filaments, composed of cells ∼10 μm wide and ∼3 μm tall) revealed individual as well as group-coordinated motility. When placed in a petri dish and dispersed in ground water from the sinkhole, filaments re-aggregated into defined colonies within minutes, then dispersed again. Speed of individual filaments increased with temperature from ∼50 μm min(-1) or ∼15 body lengths min(-1) at 10°C to ∼215 μm min(-1) or ∼70 body lengths min(-1) at 35°C - rates that are rapid relative to non-flagellated/ciliated microbes. Filaments exhibited precise and coordinated positive phototaxis toward pinpoints of light and congregated under the light of foil cutouts. Such light-responsive clusters showed an increase in photosynthetic yield - suggesting phototactic motility aids in light acquisition as well as photosynthesis. Once light source was removed, filaments slowly spread out evenly and re-aggregated, demonstrating coordinated movement through inter-filament communication regardless of light. Pebbles and pieces of broken shells placed upon intact mat were quickly covered by vertically motile filaments within hours and became fully buried in the anoxic sediments over 3-4 diurnal cycles - likely facilitating the preservation of falling debris. Coordinated horizontal and vertical filament motility optimize mat cohesion and dynamics, photosynthetic efficiency and sedimentary carbon burial in modern-day sinkhole habitats that resemble the shallow seas in Earth's early history. Analogous cyanobacterial motility may have played a key role in the oxygenation of the planet by optimizing photosynthesis while favoring carbon burial.
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Affiliation(s)
- Bopaiah A. Biddanda
- Annis Water Resources Institute, Grand Valley State University, MuskegonMI, USA
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Rugheimer S, Segura A, Kaltenegger L, Sasselov D. UV SURFACE ENVIRONMENT OF EARTH-LIKE PLANETS ORBITING FGKM STARS THROUGH GEOLOGICAL EVOLUTION. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/0004-637x/806/1/137] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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24
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Al-Beloshei NE, Al-Awadhi HA, Al-Khalaf RAR, Oommen S, Afzal M. Biocatalyzed transformation of progesterone by Geobacillus gargensis DSM 15378. APPL BIOCHEM MICRO+ 2015. [DOI: 10.1134/s0003683815030023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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25
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Hoffmann D, Maldonado J, Wojciechowski MF, Garcia-Pichel F. Hydrogen export from intertidal cyanobacterial mats: sources, fluxes and the influence of community composition. Environ Microbiol 2015; 17:3738-53. [DOI: 10.1111/1462-2920.12769] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 12/23/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Dörte Hoffmann
- School of Life Sciences; Arizona State University; Tempe AZ 85287-4501 USA
| | - Juan Maldonado
- School of Life Sciences; Arizona State University; Tempe AZ 85287-4501 USA
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Two new Beggiatoa species inhabiting marine mangrove sediments in the Caribbean. PLoS One 2015; 10:e0117832. [PMID: 25689402 PMCID: PMC4331518 DOI: 10.1371/journal.pone.0117832] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/31/2014] [Indexed: 11/19/2022] Open
Abstract
Beggiatoaceae, giant sulphur-oxidizing bacteria, are well known to occur in cold and temperate waters, as well as hydrothermal vents, where they form dense mats on the floor. However, they have never been described in tropical marine mangroves. Here, we describe two new species of benthic Beggiatoaceae colonizing a marine mangrove adjacent to mangrove roots. We combined phylogenetic and lipid analysis with electron microscopy in order to describe these organisms. Furthermore, oxygen and sulphide measurements in and ex situ were performed in a mesocosm to characterize their environment. Based on this, two new species, Candidatus Maribeggiatoa sp. and Candidatus Isobeggiatoa sp. inhabiting tropical marine mangroves in Guadeloupe were identified. The species identified as Candidatus Maribeggiatoa group suggests that this genus could harbour a third cluster with organisms ranging from 60 to 120 μm in diameter. This is also the first description of an Isobeggiatoa species outside of Arctic and temperate waters. The multiphasic approach also gives information about the environment and indications for the metabolism of these bacteria. Our study shows the widespread occurrence of members of Beggiatoaceae family and provides new insight in their potential role in shallow-water marine sulphide-rich environments such as mangroves.
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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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A model of filamentous cyanobacteria leading to reticulate pattern formation. Life (Basel) 2014; 4:433-56. [PMID: 25370380 PMCID: PMC4206854 DOI: 10.3390/life4030433] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/09/2014] [Accepted: 08/14/2014] [Indexed: 12/03/2022] Open
Abstract
The filamentous cyanobacterium, Pseudanabaena, has been shown to produce reticulate patterns that are thought to be the result of its gliding motility. Similar fossilized structures found in the geological record constitute some of the earliest signs of life on Earth. It is difficult to tie these fossils, which are billions of years old, directly to the specific microorganisms that built them. Identifying the physicochemical conditions and microorganism properties that lead microbial mats to form macroscopic structures can lead to a better understanding of the conditions on Earth at the dawn of life. In this article, a cell-based model is used to simulate the formation of reticulate patterns in cultures of Pseudanabaena. A minimal system of long and flexible trichomes capable of gliding motility is shown to be sufficient to produce stable patterns consisting of a network of streams. Varying model parameters indicate that systems with little to no cohesion, high trichome density and persistent movement are conducive to reticulate pattern formation, in conformance with experimental observations.
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Kothari A, Vaughn M, Garcia-Pichel F. Comparative genomic analyses of the cyanobacterium, Lyngbya aestuarii BL J, a powerful hydrogen producer. Front Microbiol 2013; 4:363. [PMID: 24376438 PMCID: PMC3858816 DOI: 10.3389/fmicb.2013.00363] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Accepted: 11/15/2013] [Indexed: 11/13/2022] Open
Abstract
The filamentous, non-heterocystous cyanobacterium Lyngbya aestuarii is an important contributor to marine intertidal microbial mats system worldwide. The recent isolate L. aestuarii BL J, is an unusually powerful hydrogen producer. Here we report a morphological, ultrastructural, and genomic characterization of this strain to set the basis for future systems studies and applications of this organism. The filaments contain circa 17 μm wide trichomes, composed of stacked disk-like short cells (2 μm long), encased in a prominent, laminated exopolysaccharide sheath. Cellular division occurs by transversal centripetal growth of cross-walls, where several rounds of division proceed simultaneously. Filament division occurs by cell self-immolation of one or groups of cells (necridial cells) at the breakage point. Short, sheath-less, motile filaments (hormogonia) are also formed. Morphologically and phylogenetically L. aestuarii belongs to a clade of important cyanobacteria that include members of the marine Trichodesmiun and Hydrocoleum genera, as well as terrestrial Microcoleus vaginatus strains, and alkalyphilic strains of Arthrospira. A draft genome of strain BL J was compared to those of other cyanobacteria in order to ascertain some of its ecological constraints and biotechnological potential. The genome had an average GC content of 41.1%. Of the 6.87 Mb sequenced, 6.44 Mb was present as large contigs (>10,000 bp). It contained 6515 putative protein-encoding genes, of which, 43% encode proteins of known functional role, 26% corresponded to proteins with domain or family assignments, 19.6% encode conserved hypothetical proteins, and 11.3% encode apparently unique hypothetical proteins. The strain's genome reveals its adaptations to a life of exposure to intense solar radiation and desiccation. It likely employs the storage compounds, glycogen, and cyanophycin but no polyhydroxyalkanoates, and can produce the osmolytes, trehalose, and glycine betaine. According to its genome, BL J strain also has the potential to produce a plethora of products of biotechnological interest such as Curacin A, Barbamide, Hemolysin-type calcium-binding toxin, the suncreens scytonemin, and mycosporines, as well as heptadecane and pentadecane alkanes. With respect to hydrogen production, initial comparisons of the genetic architecture and sequence of relevant genes and loci, and a comparative model of protein structure of the NiFe bidirectional hydrogenase, did not reveal conspicuous differences that could explain its unusual hydrogen producing capacity.
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Affiliation(s)
- Ankita Kothari
- School of Life Sciences, Arizona State University Tempe, AZ, USA
| | - Michael Vaughn
- Department of Chemistry and Biochemistry, Arizona State University Tempe, AZ, USA
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Tamulonis C, Postma M, Kaandorp J. Modeling filamentous cyanobacteria reveals the advantages of long and fast trichomes for optimizing light exposure. PLoS One 2011; 6:e22084. [PMID: 21789215 PMCID: PMC3138769 DOI: 10.1371/journal.pone.0022084] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 06/14/2011] [Indexed: 11/18/2022] Open
Abstract
Cyanobacteria form a very large and diverse phylum of prokaryotes that perform oxygenic photosynthesis. Many species of cyanobacteria live colonially in long trichomes of hundreds to thousands of cells. Of the filamentous species, many are also motile, gliding along their long axis, and display photomovement, by which a trichome modulates its gliding according to the incident light. The latter has been found to play an important role in guiding the trichomes to optimal lighting conditions, which can either inhibit the cells if the incident light is too weak, or damage the cells if too strong. We have developed a computational model for gliding filamentous photophobic cyanobacteria that allows us to perform simulations on the scale of a Petri dish using over 10(5) individual trichomes. Using the model, we quantify the effectiveness of one commonly observed photomovement strategy--photophobic responses--in distributing large populations of trichomes optimally over a light field. The model predicts that the typical observed length and gliding speeds of filamentous cyanobacteria are optimal for the photophobic strategy. Therefore, our results suggest that not just photomovement but also the trichome shape itself improves the ability of the cyanobacteria to optimize their light exposure.
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Affiliation(s)
- Carlos Tamulonis
- Informatics Institute, University of Amsterdam, Amsterdam, The Netherlands.
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31
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Miller AW, Blackwelder P, Al-Sayegh H, Richardson LL. Fine-structural analysis of black band disease-infected coral reveals boring cyanobacteria and novel bacteria. DISEASES OF AQUATIC ORGANISMS 2011; 93:179-190. [PMID: 21516970 DOI: 10.3354/dao02305] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Examination of coral fragments infected with black band disease (BBD) at the fine- and ultrastructural levels using scanning (SEM) and transmission electron microscopy (TEM) revealed novel features of the disease. SEM images of the skeleton from the host coral investigated (Montastraea annularis species complex) revealed extensive boring underneath the BBD mat, with cyanobacterial filaments present within some of the bore holes. Cyanobacteria were observed to penetrate into the overlying coral tissue from within the skeleton and were present throughout the mesoglea between tissue layers (coral epidermis and gastrodermis). A population of novel, as yet unidentified, small filamentous bacteria was found at the leading edge of the migrating band. This population increased in number within the band and was present within degrading coral epithelium, suggesting a role in disease etiology. In coral tissue in front of the leading edge of the band, cyanobacterial filaments were observed to be emerging from bundles of sloughed-off epidermal tissue. Degraded gastrodermis that contained actively dividing zooxanthellae was observed using both TEM and SEM. The BBD mat contained cyanobacterial filaments that were twisted, characteristic of negative-tactic responses. Some evidence of boring was found in apparently healthy control coral fragments; however, unlike in BBD-infected fragments, there were no associated cyanobacteria. These results suggest the coral skeleton as a possible source of pathogenic BBD cyanobacteria. Additionally, SEM revealed the presence of a potentially important group of small, filamentous BBD-associated bacteria yet to be identified.
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Affiliation(s)
- Aaron W Miller
- Department of Biological Sciences, Florida International University, Miami, Florida 33199, USA.
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32
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The Role of Sulfate Reduction in Stromatolites and Microbial Mats: Ancient and Modern Perspectives. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/978-94-007-0397-1_25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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Bebout BM, Garcia-Pichel F. UV B-Induced Vertical Migrations of Cyanobacteria in a Microbial Mat. Appl Environ Microbiol 2010; 61:4215-22. [PMID: 16535178 PMCID: PMC1388643 DOI: 10.1128/aem.61.12.4215-4222.1995] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Exposure to moderate doses of UV B (0.35 to 0.79 W m(sup-2) s(sup-1) or 0.98 to 2.2 (mu)mol of photons m(sup-2) s(sup-1) at 310 nm) caused the surface layers of microbial mats from Solar Lake, Sinai, Egypt, to become visibly lighter green. Concurrent with the color change were rapid and dramatic reductions in gross photosynthesis and in the resultant high porewater oxygen concentrations in the surface layers of the mats. The depths at which both maximum gross photosynthesis and maximum oxygen concentrations occurred were displaced downward. In contrast, gross photosynthesis in the deeper layers of the mats increased in response to UV B incident upon the surface. The cessation of exposure to UV B partially reversed all of these changes. Taken together, these responses suggest that photoautotrophic members of the mat community, most likely the dominant cyanobacterium Microcoleus chthonoplastes, were migrating in response to the added UV B. The migration phenomenon was also observed in response to increases in visible radiation and UV A, but UV B was ca. 100-fold more effective than visible radiation and ca. 20-fold more effective than UV A in provoking the response. Migrating microorganisms within this mat are apparently able to sense UV B directly and respond behaviorally to limit their exposure to UV. Because of strong vertical gradients of light and dissolved substances in microbial mats, the migration and the resultant vertical redistribution of photosynthetic activity have important consequences for both the photobiology of the cyanobacteria and the net primary productivity of the mat ecosystem.
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34
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Environmental Dynamics, Community Structure and Function in a Hypersaline Microbial Mat. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/978-90-481-3799-2_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Brady AL, Slater G, Laval B, Lim DS. Constraining carbon sources and growth rates of freshwater microbialites in Pavilion Lake using (14)C analysis. GEOBIOLOGY 2009; 7:544-555. [PMID: 19702837 DOI: 10.1111/j.1472-4669.2009.00215.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This study determined the natural abundance isotopic compositions ((13)C, (14)C) of the primary carbon pools and microbial communities associated with modern freshwater microbialites located in Pavilion Lake, British Columbia, Canada. The Delta(14)C of dissolved inorganic carbon (DIC) was constant throughout the water column and consistent with a primarily atmospheric source. Observed depletions in DIC (14)C values compared with atmospheric CO(2) indicated effects due either to DIC residence time and/or inputs of (14)C-depleted groundwater. Mass balance comparisons of local and regional groundwater indicate that groundwater DIC could contribute a maximum of 9-13% of the DIC. (14)C analysis of microbial phospholipid fatty acids from microbialite communities had Delta(14)C values comparable with lake water DIC, demonstrating that lake water DIC was their primary carbon source. Microbialite carbonate was also primarily derived from DIC. However, some depletion in microbialite carbonate (14)C relative to lake water DIC occurred, due either to residence time or mixing with a (14)C-depleted carbon source. A detrital branch covered with microbialite growth was used to estimate a microbialite growth rate of 0.05 mm year(-1) for the past 1000 years, faster than previous estimates for this system. These results demonstrate that the microbialites are actively growing and that the primary carbon source for both microbial communities and recent carbonate is DIC originating from the atmosphere. While these data cannot conclusively differentiate between abiotic and biotic formation mechanisms, the evidence for minor inputs of groundwater-derived DIC is consistent with the previously hypothesized biological origin of the Pavilion Lake microbialites.
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Affiliation(s)
- A L Brady
- School of Geography and Earth Sciences, McMaster University, Hamilton, ON, Canada
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Kohls K, Abed RMM, Polerecky L, Weber M, de Beer D. Halotaxis of cyanobacteria in an intertidal hypersaline microbial mat. Environ Microbiol 2009; 12:567-75. [PMID: 19919535 DOI: 10.1111/j.1462-2920.2009.02095.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An intertidal hypersaline cyanobacterial mat from Abu Dhabi (United Arab Emirates) exhibited a reversible change in its surface colour within several hours upon changes in salinity of the overlying water. The mat surface was orange-reddish at salinities above 15% and turned dark green at lower salinities. We investigated this phenomenon using a polyphasic approach that included denaturing gradient gel electrophoresis, microscopy, high-performance liquid chromatography, hyperspectral imaging, absorption spectroscopy, oxygen microsensor measurements and modelling of salinity dynamics. Filaments of Microcoleus chthonoplastes, identified based on 16S rRNA sequencing and morphology, were found to migrate up and down when salinity was decreased below or increased above 15%, respectively, causing the colour change of the mat uppermost layer. Migration occurred in light and in the dark, and could be induced by different salts, not only NaCl. The influence of salinity-dependent and independent physico-chemical parameters, such as water activity, oxygen solubility, H2S, gravity and light, was excluded, indicating that the observed migration was due to a direct response to salt stress. We propose to term this salinity-driven cyanobacterial migration as 'halotaxis', a process that might play a vital role in the survival of cyanobacteria in environments exposed to continuous salinity fluctuations such as intertidal flats.
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Affiliation(s)
- Katharina Kohls
- Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.
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37
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Cabrol NA, Grin EA, Chong G, Minkley E, Hock AN, Yu Y, Bebout L, Fleming E, Häder DP, Demergasso C, Gibson J, Escudero L, Dorador C, Lim D, Woosley C, Morris RL, Tambley C, Gaete V, Galvez ME, Smith E, Uskin-Peate I, Salazar C, Dawidowicz G, Majerowicz J. The High-Lakes Project. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jg000818] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Nathalie A. Cabrol
- Space Science and Astrobiology Division; NASA Ames Research Center; Moffett Field California USA
- SETI Carl Sagan Center; Mountain View California USA
| | - Edmond A. Grin
- Space Science and Astrobiology Division; NASA Ames Research Center; Moffett Field California USA
- SETI Carl Sagan Center; Mountain View California USA
| | - Guillermo Chong
- Centro de Investigación Científica y Tecnológica para Minería; Santiago Chile
| | - Edwin Minkley
- Department of Biological Sciences; Carnegie Mellon University; Pittsburgh Pennsylvania USA
| | - Andrew N. Hock
- Department of Earth and Space Sciences; University of California; Los Angeles California USA
| | - Youngseob Yu
- Department of Civil and Environmental Engineering; Carnegie Mellon University; Pittsburgh Pennsylvania USA
| | - Leslie Bebout
- Space Science and Astrobiology Division; NASA Ames Research Center; Moffett Field California USA
| | - Erich Fleming
- Space Science and Astrobiology Division; NASA Ames Research Center; Moffett Field California USA
| | - Donat P. Häder
- Department Botanik; University of Erlangen; Erlangen Germany
| | - Cecilia Demergasso
- Centro de Biotecnología; Universidad Católica del Norte; Antofagasta Chile
| | - John Gibson
- Marine Research Laboratories, Tasmanian Aquaculture and Fisheries Institute; University of Tasmania; Hobart, Tasmania Australia
| | - Lorena Escudero
- Centro de Investigación Científica y Tecnológica para Minería; Santiago Chile
| | - Cristina Dorador
- Centro de Biotecnología; Universidad Católica del Norte; Antofagasta Chile
| | - Darlene Lim
- Space Science and Astrobiology Division; NASA Ames Research Center; Moffett Field California USA
- SETI Carl Sagan Center; Mountain View California USA
| | - Clayton Woosley
- Space Science and Astrobiology Division; NASA Ames Research Center; Moffett Field California USA
- SETI Carl Sagan Center; Mountain View California USA
| | | | | | - Victor Gaete
- Departamento de Química; Universidad Católica del Norte; Antofagasta Chile
| | | | - Eric Smith
- Discoverer Ketty Lund Exploration Vessel; Key West Florida USA
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Bailey JV, Orphan VJ, Joye SB, Corsetti FA. Chemotrophic microbial mats and their potential for preservation in the rock record. ASTROBIOLOGY 2009; 9:843-859. [PMID: 19968462 DOI: 10.1089/ast.2008.0314] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Putative microbialites are commonly regarded to have formed in association with photosynthetic microorganisms, such as cyanobacteria. However, many modern microbial mat ecosystems are dominated by chemotrophic bacteria and archaea. Like phototrophs, filamentous sulfur-oxidizing bacteria form large mats at the sediment/water interface that can act to stabilize sediments, and their metabolic activities may mediate the formation of marine phosphorites. Similarly, bacteria and archaea associated with the anaerobic oxidation of methane (AOM) catalyze the precipitation of seafloor authigenic carbonates. When preserved, lipid biomarkers, isotopic signatures, body fossils, and lithological indicators of the local depositional environment may be used to identify chemotrophic mats in the rock record. The recognition of chemotrophic communities in the rock record has the potential to transform our understanding of ancient microbial ecologies, evolution, and geochemical conditions. Chemotrophic microbes on Earth occupy naturally occurring interfaces between oxidized and reduced chemical species and thus may provide a new set of search criteria to target life-detection efforts on other planets.
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Affiliation(s)
- Jake V Bailey
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA.
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39
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Characterization of halophiles isolated from solar salterns in Baja California, Mexico. Extremophiles 2009; 13:643-56. [DOI: 10.1007/s00792-009-0247-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Accepted: 04/14/2009] [Indexed: 10/20/2022]
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40
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Dillon JG, Miller S, Bebout B, Hullar M, Pinel N, Stahl DA. Spatial and temporal variability in a stratified hypersaline microbial mat community. FEMS Microbiol Ecol 2009; 68:46-58. [PMID: 19175677 DOI: 10.1111/j.1574-6941.2009.00647.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Hypersaline microbial mat communities have recently been shown to be more diverse than once thought. The variability in community composition of hypersaline mats, both in terms of spatial and temporal dimensions, is still poorly understood. Because this information is essential to understanding the complex biotic and abiotic interactions within these communities, terminal restriction fragment analysis and 16S rRNA gene sequencing were used to characterize the near-surface community of a hypersaline microbial mat in Guerrero Negro, Mexico. Core samples were analyzed to assay community variability over large regional scales (centimeter to kilometer) and to track depth-related changes in population distribution at 250-microm intervals over a diel period. Significant changes in total species diversity were observed at increasing distances across the mat surface; however, key species (e.g. Microcoleus sp.) were identified throughout the mat. The vertical position and abundance of >50% of the 60 peaks detected varied dramatically over a diel cycle, including Beggiatoa sp., cyanobacteria, Chloroflexus sp., Halochromatium sp., Bacteroidetes sp. and several as-yet-identified bacteria. Many of these migrations correlated strongly with diel changes in redox conditions within the mat, contributing to strong day-night community structure differences.
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Affiliation(s)
- Jesse G Dillon
- Department of Microbiology & NASA Astrobiology Institute, University of Washington, Seattle, WA, USA.
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41
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Kamp A, Røy H, Schulz-Vogt HN. Video-supported analysis of Beggiatoa filament growth, breakage, and movement. MICROBIAL ECOLOGY 2008; 56:484-91. [PMID: 18335158 PMCID: PMC2755761 DOI: 10.1007/s00248-008-9367-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2007] [Revised: 12/06/2007] [Accepted: 01/27/2008] [Indexed: 05/05/2023]
Abstract
A marine Beggiatoa sp. was cultured in semi-solid agar with opposing oxygen-sulfide gradients. Growth pattern, breakage of filaments for multiplication, and movement directions of Beggiatoa filaments in the transparent agar were investigated by time-lapse video recording. The initial doubling time of cells was 15.7 +/- 1.3 h (mean +/- SD) at room temperature. Filaments grew up to an average length of 1.7 +/- 0.2 mm, but filaments of up to approximately 6 mm were also present. First breakages of filaments occurred approximately 19 h after inoculation, and time-lapse movies illustrated that a parent filament could break into several daughter filaments within a few hours. In >20% of the cases, filament breakage occurred at the tip of a former loop. As filament breakage is accomplished by the presence of sacrificial cells, loop formation and the presence of sacrificial cells must coincide. We hypothesize that sacrificial cells enhance the chance of loop formation by interrupting the communication between two parts of one filament. With communication interrupted, these two parts of one filament can randomly move toward each other forming the tip of a loop at the sacrificial cell.
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Affiliation(s)
- Anja Kamp
- Institute for Microbiology, Leibniz University of Hannover, Hannover, Germany.
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42
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Millimeter-scale genetic gradients and community-level molecular convergence in a hypersaline microbial mat. Mol Syst Biol 2008; 4:198. [PMID: 18523433 PMCID: PMC2483411 DOI: 10.1038/msb.2008.35] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Accepted: 04/28/2008] [Indexed: 11/23/2022] Open
Abstract
To investigate the extent of genetic stratification in structured microbial communities, we compared the metagenomes of 10 successive layers of a phylogenetically complex hypersaline mat from Guerrero Negro, Mexico. We found pronounced millimeter-scale genetic gradients that were consistent with the physicochemical profile of the mat. Despite these gradients, all layers displayed near-identical and acid-shifted isoelectric point profiles due to a molecular convergence of amino-acid usage, indicating that hypersalinity enforces an overriding selective pressure on the mat community.
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43
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Mußmann M, Hu FZ, Richter M, de Beer D, Preisler A, Jørgensen BB, Huntemann M, Glöckner FO, Amann R, Koopman WJH, Lasken RS, Janto B, Hogg J, Stoodley P, Boissy R, Ehrlich GD. Insights into the genome of large sulfur bacteria revealed by analysis of single filaments. PLoS Biol 2007; 5:e230. [PMID: 17760503 PMCID: PMC1951784 DOI: 10.1371/journal.pbio.0050230] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 06/26/2007] [Indexed: 11/19/2022] Open
Abstract
Marine sediments are frequently covered by mats of the filamentous Beggiatoa and other large nitrate-storing bacteria that oxidize hydrogen sulfide using either oxygen or nitrate, which they store in intracellular vacuoles. Despite their conspicuous metabolic properties and their biogeochemical importance, little is known about their genetic repertoire because of the lack of pure cultures. Here, we present a unique approach to access the genome of single filaments of Beggiatoa by combining whole genome amplification, pyrosequencing, and optical genome mapping. Sequence assemblies were incomplete and yielded average contig sizes of approximately 1 kb. Pathways for sulfur oxidation, nitrate and oxygen respiration, and CO2 fixation confirm the chemolithoautotrophic physiology of Beggiatoa. In addition, Beggiatoa potentially utilize inorganic sulfur compounds and dimethyl sulfoxide as electron acceptors. We propose a mechanism of vacuolar nitrate accumulation that is linked to proton translocation by vacuolar-type ATPases. Comparative genomics indicates substantial horizontal gene transfer of storage, metabolic, and gliding capabilities between Beggiatoa and cyanobacteria. These capabilities enable Beggiatoa to overcome non-overlapping availabilities of electron donors and acceptors while gliding between oxic and sulfidic zones. The first look into the genome of these filamentous sulfur-oxidizing bacteria substantially deepens the understanding of their evolution and their contribution to sulfur and nitrogen cycling in marine sediments.
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Affiliation(s)
- Marc Mußmann
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- * To whom correspondence should be addressed. E-mail: (MM); (FOG); (GDE)
| | - Fen Z Hu
- Center for Genomic Sciences, Allegheny General Hospital/Allegheny-Singer Research Institute, Pittsburgh, Pennsylvania, United States of America
| | - Michael Richter
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- School of Engineering and Sciences, Jacobs University Bremen, Bremen, Germany
| | - Dirk de Beer
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - André Preisler
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Bo B Jørgensen
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Marcel Huntemann
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- School of Engineering and Sciences, Jacobs University Bremen, Bremen, Germany
| | - Frank Oliver Glöckner
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- School of Engineering and Sciences, Jacobs University Bremen, Bremen, Germany
- * To whom correspondence should be addressed. E-mail: (MM); (FOG); (GDE)
| | - Rudolf Amann
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Werner J. H Koopman
- Department of Membrane Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Roger S Lasken
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Benjamin Janto
- Center for Genomic Sciences, Allegheny General Hospital/Allegheny-Singer Research Institute, Pittsburgh, Pennsylvania, United States of America
| | - Justin Hogg
- Center for Genomic Sciences, Allegheny General Hospital/Allegheny-Singer Research Institute, Pittsburgh, Pennsylvania, United States of America
| | - Paul Stoodley
- Center for Genomic Sciences, Allegheny General Hospital/Allegheny-Singer Research Institute, Pittsburgh, Pennsylvania, United States of America
| | - Robert Boissy
- Center for Genomic Sciences, Allegheny General Hospital/Allegheny-Singer Research Institute, Pittsburgh, Pennsylvania, United States of America
| | - Garth D Ehrlich
- Center for Genomic Sciences, Allegheny General Hospital/Allegheny-Singer Research Institute, Pittsburgh, Pennsylvania, United States of America
- * To whom correspondence should be addressed. E-mail: (MM); (FOG); (GDE)
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44
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Gupta S, Agrawal SC. Motility in Oscillatoria salina as affected by different factors. Folia Microbiol (Praha) 2007; 51:565-71. [PMID: 17455793 DOI: 10.1007/bf02931621] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
All 3-10-d-old Oscillatoria salina filaments glide with the speed of 323-330 microm/min (BG 11 medium, pH 7.5, 21 +/- 2 degrees C, continuous light intensity of approximately 30 micromol m(-2) s(-1)) in a culture chamber. However, a time bound progressive decrease in gliding speed and in percentage of gliding filaments occurred, depending upon the severity of different stress factors studied, viz. water stress (2-8% agarized media, liquid media with 0.2-1 mol/L NaCl, blot-dryness of filaments for > or = 5 min), temperature shock (5, 40 degrees C for > or = 5 min; 35 degrees C for > or = 15 min), darkness and low light intensity (2, 10 micromol m(-2) s(-1)), UV exposure (0.96-3.84 kJ/m2), pH extremes (< or = 6.5 and > or = 9.5), lack of all nutrients from liquid medium (double distilled water), presence of 'heavy' metals (1, 25 ppm Fe, Cu, Zn, Ni, Co, Hg) or organic substances in liquid medium (25, 250 ppm 2,4-D, captan, urea, DDT, thiourea). This feature of the alga (i.e. reduction in speed and percentage of gliding filaments depending upon severity of stress conditions) may thus be suggested to be used in assessing water quality.
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Affiliation(s)
- S Gupta
- Department of Botany, University of Allahabad, India
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Hinck S, Neu TR, Lavik G, Mussmann M, de Beer D, Jonkers HM. Physiological adaptation of a nitrate-storing Beggiatoa sp. to diel cycling in a phototrophic hypersaline mat. Appl Environ Microbiol 2007; 73:7013-22. [PMID: 17766448 PMCID: PMC2074952 DOI: 10.1128/aem.00548-07] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to investigate the supposed vertical diel migration and the accompanying physiology of Beggiatoa bacteria from hypersaline microbial mats. We combined microsensor, stable-isotope, and molecular techniques to clarify the phylogeny and physiology of the most dominant species inhabiting mats of the natural hypersaline Lake Chiprana, Spain. The most dominant morphotype had a filament diameter of 6 to 8 microm and a length varying from 1 to >10 mm. Phylogenetic analysis by 16S rRNA gene comparison revealed that this type appeared to be most closely related (91% sequence identity) to the narrow (4-microm diameter) nonvacuolated marine strain MS-81-6. Stable-isotope analysis showed that the Lake Chiprana species could store nitrate intracellularly to 40 mM. The presence of large intracellular vacuoles was confirmed by fluorescein isothiocyanate staining and subsequent confocal microscopy. In illuminated mats, their highest abundance was found at a depth of 8 mm, where oxygen and sulfide co-occurred. However, in the dark, the highest Beggiatoa densities occurred at 7 mm, and the whole population was present in the anoxic zone of the mat. Our findings suggest that hypersaline Beggiatoa bacteria oxidize sulfide with oxygen under light conditions and with internally stored nitrate under dark conditions. It was concluded that nitrate storage by Beggiatoa is an optimal strategy to both occupy the suboxic zones in sulfidic sediments and survive the dark periods in phototrophic mats.
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Affiliation(s)
- Susanne Hinck
- Max Planck Institute for Marine Microbiology, Celsiusstr. 1, D-28359 Bremen, Germany.
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Myers JL, Sekar R, Richardson LL. Molecular detection and ecological significance of the cyanobacterial genera Geitlerinema and Leptolyngbya in black band disease of corals. Appl Environ Microbiol 2007; 73:5173-82. [PMID: 17601818 PMCID: PMC1950983 DOI: 10.1128/aem.00900-07] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Black band disease (BBD) is a pathogenic, sulfide-rich microbial mat dominated by filamentous cyanobacteria that infect corals worldwide. We isolated cyanobacteria from BBD into culture, confirmed their presence in the BBD community by using denaturing gradient gel electrophoresis (DGGE), and demonstrated their ecological significance in terms of physiological sulfide tolerance and photosynthesis-versus-irradiance values. Twenty-nine BBD samples were collected from nine host coral species, four of which have not previously been investigated, from reefs of the Florida Keys, the Bahamas, St. Croix, and the Philippines. From these samples, seven cyanobacteria were isolated into culture. Cloning and sequencing of the 16S rRNA gene using universal primers indicated that four isolates were related to the genus Geitlerinema and three to the genus Leptolyngbya. DGGE results, obtained using Cyanobacteria-specific 16S rRNA primers, revealed that the most common BBD cyanobacterial sequence, detected in 26 BBD field samples, was related to that of an Oscillatoria sp. The next most common sequence, 99% similar to that of the Geitlerinema BBD isolate, was present in three samples. One Leptolyngbya- and one Phormidium-related sequence were also found. Laboratory experiments using isolates of BBD Geitlerinema and Leptolyngbya revealed that they could carry out sulfide-resistant oxygenic photosynthesis, a relatively rare characteristic among cyanobacteria, and that they are adapted to the sulfide-rich, low-light BBD environment. The presence of the cyanotoxin microcystin in these cultures and in BBD suggests a role in BBD pathogenicity. Our results confirm the presence of Geitlerinema in the BBD microbial community and its ecological significance, which have been challenged, and provide evidence of a second ecologically significant BBD cyanobacterium, Leptolyngbya.
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Affiliation(s)
- Jamie L Myers
- Department of Biological Sciences, Florida International University, Miami, FL 33199, USA.
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Biological and chemical sulfide oxidation in a Beggiatoa inhabited marine sediment. ISME JOURNAL 2007; 1:341-53. [DOI: 10.1038/ismej.2007.50] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Díez B, Bauer K, Bergman B. Epilithic cyanobacterial communities of a marine tropical beach rock (Heron Island, Great Barrier Reef): diversity and diazotrophy. Appl Environ Microbiol 2007; 73:3656-68. [PMID: 17416688 PMCID: PMC1932695 DOI: 10.1128/aem.02067-06] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The diversity and nitrogenase activity of epilithic marine microbes in a Holocene beach rock (Heron Island, Great Barrier Reef, Australia) with a proposed biological calcification "microbialite" origin were examined. Partial 16S rRNA gene sequences from the dominant mat (a coherent and layered pink-pigmented community spread over the beach rock) and biofilms (nonstratified, differently pigmented microbial communities of small shallow depressions) were retrieved using denaturing gradient gel electrophoresis (DGGE), and a clone library was retrieved from the dominant mat. The 16S rRNA gene sequences and morphological analyses revealed heterogeneity in the cyanobacterial distribution patterns. The nonheterocystous filamentous genus Blennothrix sp., phylogenetically related to Lyngbya, dominated the mat together with unidentified nonheterocystous filaments of members of the Pseudanabaenaceae and the unicellular genus Chroococcidiopsis. The dominance and three-dimensional intertwined distribution of these organisms were confirmed by nonintrusive scanning microscopy. In contrast, the less pronounced biofilms were dominated by the heterocystous cyanobacterial genus Calothrix, two unicellular Entophysalis morphotypes, Lyngbya spp., and members of the Pseudanabaenaceae family. Cytophaga-Flavobacterium-Bacteroides and Alphaproteobacteria phylotypes were also retrieved from the beach rock. The microbial diversity of the dominant mat was accompanied by high nocturnal nitrogenase activities (as determined by in situ acetylene reduction assays). A new DGGE nifH gene optimization approach for cyanobacterial nitrogen fixers showed that the sequences retrieved from the dominant mat were related to nonheterocystous uncultured cyanobacterial phylotypes, only distantly related to sequences of nitrogen-fixing cultured cyanobacteria. These data stress the occurrence and importance of nonheterocystous epilithic cyanobacteria, and it is hypothesized that such epilithic cyanobacteria are the principal nitrogen fixers of the Heron Island beach rock.
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MESH Headings
- Acetylene/metabolism
- Australia
- Biodiversity
- Cluster Analysis
- Cyanobacteria/classification
- Cyanobacteria/cytology
- Cyanobacteria/isolation & purification
- Cyanobacteria/physiology
- DNA, Bacterial/chemistry
- DNA, Bacterial/genetics
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- Electrophoresis, Polyacrylamide Gel
- Gene Library
- Genes, rRNA
- Microscopy, Electron, Scanning
- Molecular Sequence Data
- Nitrogen Fixation
- Nitrogenase/metabolism
- Nucleic Acid Denaturation
- Oxidoreductases/genetics
- Pacific Ocean
- Phylogeny
- RNA, Bacterial/genetics
- RNA, Ribosomal, 16S/genetics
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- Soil Microbiology
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Affiliation(s)
- Beatriz Díez
- Department of Botany, Stockholm University, S-10691 Stockholm, Sweden.
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Villanueva L, Navarrete A, Urmeneta J, White DC, Guerrero R. Analysis of diurnal and vertical microbial diversity of a hypersaline microbial mat. Arch Microbiol 2007; 188:137-46. [PMID: 17361455 DOI: 10.1007/s00203-007-0229-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Revised: 02/12/2007] [Accepted: 02/27/2007] [Indexed: 10/23/2022]
Abstract
Microbial mats are prokaryotic communities that provide model systems to analyze microbial diversity and ecophysiological interactions. Community diversity of microbial mat samples was assessed at 8:00 a.m. and 3:00 p.m. in a combined analysis consisting of 16S rRNA-denaturing gradient gel electrophoresis (DGGE) and phospholipid fatty acid (PLFA) profiles. The divergence index determined from PLFA and DGGE data showed that depth-related differences have a greater influence on diversity than temporal variations. Shannon and Simpson indices yielded similar values in all samples, which suggested the stable maintenance of a structurally diverse microbial community. The increased diversity observed at 3:00 p.m. between 2.5 and 4 mm can be explained mainly by diversification of anaerobic microorganisms, especially sulfate-reducing bacteria. In the afternoon sampling, the diversity index reflected a higher diversity between 4 and 5.5 mm depth, which suggested an increase in the diversity of strict anaerobes and fermenters. The results are consistent with the conclusion that hypersaline microbial mats are characterized by high degree of diversity that shifts in response to the photobiological adaptations and metabolic status of the microbial community.
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Affiliation(s)
- Laura Villanueva
- Department of Microbiology, University of Barcelona, Barcelona, Spain.
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