1
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Ecogenomics reveals viral communities across the Challenger Deep oceanic trench. Commun Biol 2022; 5:1055. [PMID: 36192584 PMCID: PMC9529941 DOI: 10.1038/s42003-022-04027-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 09/23/2022] [Indexed: 11/23/2022] Open
Abstract
Despite the environmental challenges and nutrient scarcity, the geographically isolated Challenger Deep in Mariana trench, is considered a dynamic hotspot of microbial activity. Hadal viruses are the least explored microorganisms in Challenger Deep, while their taxonomic and functional diversity and ecological impact on deep-sea biogeochemistry are poorly described. Here, we collect 13 sediment cores from slope and bottom-axis sites across the Challenger Deep (down to ~11 kilometers depth), and identify 1,628 previously undescribed viral operational taxonomic units at species level. Community-wide analyses reveals 1,299 viral genera and distinct viral diversity across the trench, which is significantly higher at the bottom-axis vs. slope sites of the trench. 77% of these viral genera have not been previously identified in soils, deep-sea sediments and other oceanic settings. Key prokaryotes involved in hadal carbon and nitrogen cycling are predicted to be potential hosts infected by these viruses. The detected putative auxiliary metabolic genes suggest that viruses at Challenger Deep could modulate the carbohydrate and sulfur metabolisms of their potential hosts, and stabilize host’s cell membranes under extreme hydrostatic pressures. Our results shed light on hadal viral metabolic capabilities, contribute to understanding deep sea ecology and on functional adaptions of hadal viruses for future research. Analysis of 13 sediment cores from the Challenger Deep of Marian Trench (down to 11 kilometers depth) identified distinct operational taxonomic units and relevant auxiliary metabolic genes, providing further insight into deep-sea viral metabolic capabilities and ecology.
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2
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Heinrichs ME, De Corte D, Engelen B, Pan D. An Advanced Protocol for the Quantification of Marine Sediment Viruses via Flow Cytometry. Viruses 2021; 13:v13010102. [PMID: 33451082 PMCID: PMC7828538 DOI: 10.3390/v13010102] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 11/16/2022] Open
Abstract
Viruses are highly abundant, diverse, and active components of marine environments. Flow cytometry has helped to increase the understanding of their impact on shaping microbial communities and biogeochemical cycles in the pelagic zone. However, to date, flow cytometric quantification of sediment viruses is still hindered by interference from the sediment matrix. Here, we developed a protocol for the enumeration of marine sediment viruses by flow cytometry based on separation of viruses from sediment particles using a Nycodenz density gradient. Results indicated that there was sufficient removal of background interference to allow for flow cytometric quantification. Applying this new protocol to deep-sea and tidal-flat samples, viral abundances enumerated by flow cytometry correlated well (R2 = 0.899) with counts assessed by epifluorescence microscopy over several orders of magnitude from marine sediments of various compositions. Further optimization may be needed for sediments with low biomass or high organic content. Overall, the new protocol enables fast and accurate quantification of marine sediment viruses, and opens up the options for virus sorting, targeted viromics, and single-virus sequencing.
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Affiliation(s)
- Mara Elena Heinrichs
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, 26129 Oldenburg, Germany; (M.E.H.); (D.D.C.); (B.E.)
| | - Daniele De Corte
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, 26129 Oldenburg, Germany; (M.E.H.); (D.D.C.); (B.E.)
| | - Bert Engelen
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, 26129 Oldenburg, Germany; (M.E.H.); (D.D.C.); (B.E.)
| | - Donald Pan
- Institute for Extra-Cutting-Edge Science and Technology Avant-Garde Research (X-Star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka 237-0061, Japan
- Department of Ecology and Environmental Studies, The Water School, Florida Gulf Coast University, Fort Myers, FL 33913, USA
- Correspondence:
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3
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Wei M, Xu K. New Insights Into the Virus-to-Prokaryote Ratio (VPR) in Marine Sediments. Front Microbiol 2020; 11:1102. [PMID: 32547525 PMCID: PMC7272709 DOI: 10.3389/fmicb.2020.01102] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 05/04/2020] [Indexed: 11/13/2022] Open
Abstract
The virus-to-prokaryote ratio (VPR), which reflects the numerical dominance of viruses over their hosts, has been proposed as a proxy for assessing the relationship between viruses and prokaryotes. Previous studies showed that VPR values fluctuate over six orders of magnitude within and across various benthic ecosystems, with an average value of approximately 10. We hypothesize that this high VPR value is largely due to the inaccurate enumeration of viruses and prokaryotes (e.g., centrifugation treatments may lead to a three-fourfold overestimation of VPR). In this study, we evaluated the impact of processing methods on the determination of VPR values. Using an optimized procedure, we investigated the marine benthic VPR at 31 sites, from intertidal zones through continental shelves to abyssal plains, and assessed its monthly variation in two contrasting intertidal habitats (muddy-sand and sandy). By compiling 135 VPR data points of surface sediments from 37 publications, we reveal the effect of centrifugation on published VPR values and describe the spatial distribution of VPR values on a larger scale based on reliable data. The results showed that the commonly used centrifugation method may result in an overestimation of VPR values that are approximately one order of magnitude higher than those obtained using the dilution method, while other processing steps had a limited impact on the VPR. Our analysis indicates that the benthic VPR value is low and less varied across temporal and spatial scales, fluctuating mostly within 10, and the average VPR is approximately 2 in both marine and freshwater habitats. An insignificant seasonal pattern in the VPR was observed in the intertidal zone, with lower VPR values occurring at high temperatures. The VPR spatial distribution was primarily associated with sediment phaeophytin a, suggesting that the trophic conditions of the upper water column and the sedimentation of organic matter to the bottom are the key factors affecting VPR values. The mean VPR in benthic habitats is approximately one order of magnitude lower and much less varied than that observed in pelagic habitats, indicating that the virus-host relationship and the ecological function of viruses in the two ecosystems may be very different.
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Affiliation(s)
- Miao Wei
- Laboratory of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Kuidong Xu
- Laboratory of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
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4
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Pan D, Morono Y, Inagaki F, Takai K. An Improved Method for Extracting Viruses From Sediment: Detection of Far More Viruses in the Subseafloor Than Previously Reported. Front Microbiol 2019; 10:878. [PMID: 31110497 PMCID: PMC6501758 DOI: 10.3389/fmicb.2019.00878] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/05/2019] [Indexed: 01/21/2023] Open
Abstract
Viruses are the most abundant biological entities on Earth and perform essential ecological functions in aquatic environments by mediating biogeochemical cycling and lateral gene transfer. Cellular life as well as viruses have been found in deep subseafloor sediment. However, the study of deep sediment viruses has been hampered by the complexities involved in efficiently extracting viruses from a sediment matrix. Here, we developed a new method for the extraction of viruses from sediment based on density separation using a Nycodenz density step gradient. The density separation method resulted in up to 2 orders of magnitude greater recovery of viruses from diverse subseafloor sediments compared to conventional methods. The density separation method also showed more consistent performance between samples of different sediment lithology, whereas conventional virus extraction methods were highly inconsistent. Using this new method, we show that previously published virus counts have underestimated viral abundances by up to 2 orders of magnitude. These improvements suggest that the carbon contained within viral biomass in the subseafloor environment may potentially be revised upward to 0.8-3.7 Gt from current estimates of 0.2 Gt. The vastly improved recovery of viruses indicate that viruses represent a far larger pool of organic carbon in subseafloor environments than previously estimated.
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Affiliation(s)
- Donald Pan
- Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan
| | - Yuki Morono
- Geomicrobiology Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Nankoku, Japan
- Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan
| | - Fumio Inagaki
- Geomicrobiology Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Nankoku, Japan
- Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan
- Research and Development Center for Ocean Drilling Science, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan
| | - Ken Takai
- Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan
- Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
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5
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Jasna V, Parvathi A, Pradeep Ram AS, Balachandran KK, Madhu NV, Nair M, Jyothibabu R, Jayalakshmy KV, Revichandran C, Sime-Ngando T. Viral-Induced Mortality of Prokaryotes in a Tropical Monsoonal Estuary. Front Microbiol 2017; 8:895. [PMID: 28588564 PMCID: PMC5440509 DOI: 10.3389/fmicb.2017.00895] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/03/2017] [Indexed: 12/02/2022] Open
Abstract
Viruses are recognized as the most abundant and dynamic biological entities in the marine and estuarine environment. However, studies on the dynamics and activity of viruses in transient estuarine systems are limited. This study examines temporal and spatial variations in viral abundance (VA) and viral activity across the salinity gradient in a monsoon-driven tropical estuarine system (Cochin estuary, CE) along the southwest coast of India. Water samples were collected from five stations (with different hydrological settings) every 3 h for 24 h period during two distinct seasons, namely pre-monsoon (PRM, dry season) and monsoon (MON, wet season). Time series measurements were made for a spring and neap tidal cycle for each season at all the stations. The results showed marked spatial and seasonal variability with relatively low diel and tidal variations in VA and lytic activity. Viral activity was found to be distinct in five stations studied with the maximum activity in the mesohaline regions (salinity <20) of the estuary. This region was characterized by high VA, lytic infection and viral production, accompanied by low (BGE) and high bacterial respiration. Based on viral lytic production, lytic viruses were found to be responsible for the release of ca. 72.9 ± 58.5 μg C L−1d−1 of bacterial carbon. The contribution of the viral shunt to the dissolved organic carbon (DOC) pool was higher during the dry season (PRM) than MON. Statistical analysis confirmed a significant association of viruses with the host availability and salinity. This work demonstrates the spatiotemporal distribution of viruses in a tropical estuarine ecosystem and highlights their role in microbial mortality across different salinity gradients. This study forms the first report on viral processes from a monsoon-driven tropical estuarine ecosystem.
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Affiliation(s)
- Vijayan Jasna
- CSIR-National Institute of Oceanography, Regional Centre (CSIR)Kochi, India
| | - Ammini Parvathi
- CSIR-National Institute of Oceanography, Regional Centre (CSIR)Kochi, India
| | - Angia Sriram Pradeep Ram
- Laboratoire Microorganismes: Génome et Environnement, UMR Centre National de la Recherche Scientifique 6023, Université Clermont-AuvergneAubière, France
| | | | - Nikathil V Madhu
- CSIR-National Institute of Oceanography, Regional Centre (CSIR)Kochi, India
| | - Maheswari Nair
- CSIR-National Institute of Oceanography, Regional Centre (CSIR)Kochi, India
| | | | | | | | - Télesphore Sime-Ngando
- Laboratoire Microorganismes: Génome et Environnement, UMR Centre National de la Recherche Scientifique 6023, Université Clermont-AuvergneAubière, France
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6
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Cabral AS, Lessa MM, Junger PC, Thompson FL, Paranhos R. Virioplankton dynamics are related to eutrophication levels in a tropical urbanized bay. PLoS One 2017; 12:e0174653. [PMID: 28362842 PMCID: PMC5376344 DOI: 10.1371/journal.pone.0174653] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 03/13/2017] [Indexed: 11/19/2022] Open
Abstract
Virioplankton are an important and abundant biological component of marine and freshwater ecosystems. Often overlooked, aquatic viruses play an important role in biogeochemical cycles on a global scale, infecting both autotrophic and heterotrophic microbes. Viral diversity, abundance, and viral interactions at different trophic levels in aqueous environments are not well understood. Tropical ecosystems are less frequently studied than temperate ecosystems, but could provide new insights into how physical and chemical variability can shape or force microbial community changes. In this study, we found high viral abundance values in Guanabara Bay relative to other estuaries around the world. Viral abundance was positively correlated with bacterioplankton abundance and chlorophyll a concentrations. Moreover, prokaryotic and viral abundance were positively correlated with eutrophication, especially in surface waters. These results provide novel baseline data on the quantitative distribution of aquatic viruses in tropical estuaries. They also provide new information on a complex and dynamic relationship in which environmental factors influence the abundance of bacterial hosts and consequently their viruses. Guanabara Bay is characterized by spatial and seasonal variations, and the eutrophication process is the most important factor explaining the structuring of virioplankton abundance and distribution in this tropical urbanized bay.
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Affiliation(s)
- Anderson S. Cabral
- Laboratory of Hydrobiology, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Graduate Program in Ecology, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Laboratory of Microbiology, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Mariana M. Lessa
- Laboratory of Hydrobiology, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Graduate Program in Ecology, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Pedro C. Junger
- Graduate Program in Ecology, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Laboratory of Limnology, Department of Ecology, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Fabiano L. Thompson
- Laboratory of Microbiology, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Rodolfo Paranhos
- Laboratory of Hydrobiology, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Graduate Program in Ecology, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
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7
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Lapygina EV, Lysak LV, Moskvina MI, Zvyagintsev DG. Virus abundance in alluvial-sod soil determined by direct epifluorescence microscopy. Microbiology (Reading) 2016. [DOI: 10.1134/s0026261716060138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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8
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Trubl G, Solonenko N, Chittick L, Solonenko SA, Rich VI, Sullivan MB. Optimization of viral resuspension methods for carbon-rich soils along a permafrost thaw gradient. PeerJ 2016; 4:e1999. [PMID: 27231649 PMCID: PMC4878379 DOI: 10.7717/peerj.1999] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 04/11/2016] [Indexed: 01/23/2023] Open
Abstract
Permafrost stores approximately 50% of global soil carbon (C) in a frozen form; it is thawing rapidly under climate change, and little is known about viral communities in these soils or their roles in C cycling. In permafrost soils, microorganisms contribute significantly to C cycling, and characterizing them has recently been shown to improve prediction of ecosystem function. In other ecosystems, viruses have broad ecosystem and community impacts ranging from host cell mortality and organic matter cycling to horizontal gene transfer and reprogramming of core microbial metabolisms. Here we developed an optimized protocol to extract viruses from three types of high organic-matter peatland soils across a permafrost thaw gradient (palsa, moss-dominated bog, and sedge-dominated fen). Three separate experiments were used to evaluate the impact of chemical buffers, physical dispersion, storage conditions, and concentration and purification methods on viral yields. The most successful protocol, amended potassium citrate buffer with bead-beating or vortexing and BSA, yielded on average as much as 2-fold more virus-like particles (VLPs) g−1 of soil than other methods tested. All method combinations yielded VLPs g−1 of soil on the 108 order of magnitude across all three soil types. The different storage and concentration methods did not yield significantly more VLPs g−1 of soil among the soil types. This research provides much-needed guidelines for resuspending viruses from soils, specifically carbon-rich soils, paving the way for incorporating viruses into soil ecology studies.
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Affiliation(s)
- Gareth Trubl
- Department of Soil, Water and Environmental Science, University of Arizona, Tucson, AZ, United States; Current affiliation: Department of Microbiology, Ohio State University, Columbus, OH, United States
| | - Natalie Solonenko
- Current affiliation: Department of Microbiology, Ohio State University, Columbus, OH, United States; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, United States
| | - Lauren Chittick
- Current affiliation: Department of Microbiology, Ohio State University, Columbus, OH, United States; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, United States
| | - Sergei A Solonenko
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, United States; Current affiliation: Department of Ecology, Evolution and Organismal Biology, Ohio State University, Columbus, OH, United States
| | - Virginia I Rich
- Department of Soil, Water and Environmental Science, University of Arizona, Tucson, AZ, United States; Current affiliation: Department of Microbiology, Ohio State University, Columbus, OH, United States
| | - Matthew B Sullivan
- Current affiliation: Department of Microbiology, Ohio State University, Columbus, OH, United States; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, United States; Current affiliation: Department of Ecology, Evolution and Organismal Biology, Ohio State University, Columbus, OH, United States; Current affiliation: Department of Civil, Environmental and Geodetic Engineering, Ohio State University, Columbus, OH, United States
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9
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Montanié H, De Crignis MG, Lavaud J. Viral Impact on Prokaryotic and Microalgal Activities in the Microphytobenthic Biofilm of an Intertidal Mudflat (French Atlantic Coast). Front Microbiol 2015; 6:1214. [PMID: 26617575 PMCID: PMC4639598 DOI: 10.3389/fmicb.2015.01214] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 10/19/2015] [Indexed: 01/20/2023] Open
Abstract
This is the first report on viriobenthos activity within the microbial biofilm located at the top-surface of the intertidal mudflat during emersion in Marennes-Oléron Bay (France). By combining in situ and ex situ approaches, the viral production (VP) was linked to the dynamics of prokaryotes and microphytobenthos (MPB). VP averaged 2–4 × 108 viruses ml−1 h−1. VP correlated positively with the Virus to Prokaryote Ratio, and both were correlated negatively with the water content. The virus-induced mortality of prokaryotes was lower in winter than in summer (6.8 vs. 39.7% of the production) and the C-shunting may supply 2–12% of their Carbon Demand, respectively. VP accounted for 79% of loss in Prokaryotes but the response was delayed compared to the increase in VP suggesting a simultaneous release of viruses of MPB origin. This hypothesis is supported by capsid-sizing of virions by transmission electronic microscopy and bioassays. Harvesting and ex situ maintenance of top-surface sediments was carried out to monitor the dynamics of viruses, prokaryotes and MPB after inoculation with benthic or planktonic viruses. Benthic viruses modified the prokaryotic and MPB dynamics and decreased the photosynthesis efficiency in contrast to planktonic viruses that impacted MPB but not the prokaryotes.
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Affiliation(s)
- Hélène Montanié
- UMRi 7266 ULR- Centre National de la Recherche Scientifique, LIENSs, Institut du Littoral et de l'Environnement, Université de La Rochelle La Rochelle, France
| | - Margot G De Crignis
- UMRi 7266 ULR- Centre National de la Recherche Scientifique, LIENSs, Institut du Littoral et de l'Environnement, Université de La Rochelle La Rochelle, France
| | - Johann Lavaud
- UMRi 7266 ULR- Centre National de la Recherche Scientifique, LIENSs, Institut du Littoral et de l'Environnement, Université de La Rochelle La Rochelle, France
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10
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Carreira C, Staal M, Middelboe M, Brussaard CPD. Counting viruses and bacteria in photosynthetic microbial mats. Appl Environ Microbiol 2015; 81:2149-55. [PMID: 25595761 PMCID: PMC4345377 DOI: 10.1128/aem.02863-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/07/2015] [Indexed: 11/20/2022] Open
Abstract
Viral abundances in benthic environments are the highest found in aquatic systems. Photosynthetic microbial mats represent benthic environments with high microbial activity and possibly high viral densities, yet viral abundances have not been examined in such systems. Existing extraction procedures typically used in benthic viral ecology were applied to the complex matrix of microbial mats but were found to inefficiently extract viruses. Here, we present a method for extraction and quantification of viruses from photosynthetic microbial mats using epifluorescence microscopy (EFM) and flow cytometry (FCM). A combination of EDTA addition, probe sonication, and enzyme treatment applied to a glutaraldehyde-fixed sample resulted in a substantially higher viral (5- to 33-fold) extraction efficiency and reduced background noise compared to previously published methods. Using this method, it was found that in general, intertidal photosynthetic microbial mats harbor very high viral abundances (2.8 × 10(10) ± 0.3 × 10(10) g(-1)) compared with benthic habitats (10(7) to 10(9) g(-1)). This procedure also showed 4.5- and 4-fold-increased efficacies of extraction of viruses and bacteria, respectively, from intertidal sediments, allowing a single method to be used for the microbial mat and underlying sediment.
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Affiliation(s)
- Cátia Carreira
- Department of Biological Oceanography, Royal Netherlands Institute for Sea Research (NIOZ), Den Burg, The Netherlands Section for Marine Biology, University of Copenhagen, Helsingør, Denmark
| | - Marc Staal
- Section for Marine Biology, University of Copenhagen, Helsingør, Denmark
| | - Mathias Middelboe
- Section for Marine Biology, University of Copenhagen, Helsingør, Denmark
| | - Corina P D Brussaard
- Department of Biological Oceanography, Royal Netherlands Institute for Sea Research (NIOZ), Den Burg, The Netherlands Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
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11
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Corinaldesi C, Tangherlini M, Luna GM, Dell'anno A. Extracellular DNA can preserve the genetic signatures of present and past viral infection events in deep hypersaline anoxic basins. Proc Biol Sci 2014; 281:20133299. [PMID: 24523277 DOI: 10.1098/rspb.2013.3299] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Deep hypersaline anoxic basins (DHABs) of the Mediterranean Sea are among the most extreme ecosystems on Earth and host abundant, active and diversified prokaryotic assemblages. However, factors influencing biodiversity and ecosystem functioning are still largely unknown. We investigated, for the first time, the impact of viruses on the prokaryotic assemblages and dynamics of extracellular DNA pool in the sediments of La Medee, the largest DHAB found on Earth. We also compared, in La Medee and L'Atalante sediments, the diversity of prokaryotic 16S rDNA sequences contained in the extracellular DNA released by virus-induced prokaryotic mortality. We found that DHAB sediments are hot-spots of viral infections, which largely contribute to the release of high amounts of extracellular DNA. DNase activities in DHAB sediments were much higher than other extracellular enzymatic activities, suggesting that extracellular DNA released from killed prokaryotes can be the most suitable trophic resource for benthic prokaryotes. Preserved extracellular DNA pools, which contained novel and diversified gene sequences, were very similar between the DHABs but dissimilar from the respective microbial DNA pools. We conclude that the strong viral impact in DHAB sediments influences the genetic composition of extracellular DNA, which can preserve the signatures of present and past infections.
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Affiliation(s)
- C Corinaldesi
- Department of Life and Environmental Sciences, Polytechnic University of Marche, , 60131 Ancona, Italy, Institute of Marine Sciences-National Research Council (ISMAR-CNR), , Castello 2737/f, 30122 Venezia, Italy
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12
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Viral infections stimulate the metabolism and shape prokaryotic assemblages in submarine mud volcanoes. ISME JOURNAL 2011; 6:1250-9. [PMID: 22170423 DOI: 10.1038/ismej.2011.185] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mud volcanoes are geological structures in the oceans that have key roles in the functioning of the global ecosystem. Information on the dynamics of benthic viruses and their interactions with prokaryotes in mud volcano ecosystems is still completely lacking. We investigated the impact of viral infection on the mortality and assemblage structure of benthic prokaryotes of five mud volcanoes in the Mediterranean Sea. Mud volcano sediments promote high rates of viral production (1.65-7.89 × 10(9) viruses g(-1) d(-1)), viral-induced prokaryotic mortality (VIPM) (33% cells killed per day) and heterotrophic prokaryotic production (3.0-8.3 μgC g(-1) d(-1)) when compared with sediments outside the mud volcano area. The viral shunt (that is, the microbial biomass converted into dissolved organic matter as a result of viral infection, and thus diverted away from higher trophic levels) provides 49 mgC m(-2) d(-1), thus fuelling the metabolism of uninfected prokaryotes and contributing to the total C budget. Bacteria are the dominant components of prokaryotic assemblages in surface sediments of mud volcanoes, whereas archaea dominate the subsurface sediment layers. Multivariate multiple regression analyses show that prokaryotic assemblage composition is not only dependant on the geochemical features and processes of mud volcano ecosystems but also on synergistic interactions between bottom-up (that is, trophic resources) and top-down (that is, VIPM) controlling factors. Overall, these findings highlight the significant role of the viral shunt in sustaining the metabolism of prokaryotes and shaping their assemblage structure in mud volcano sediments, and they provide new clues for our understanding of the functioning of cold-seep ecosystems.
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13
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Helton RR, Wang K, Kan J, Powell DH, Wommack KE. Interannual dynamics of viriobenthos abundance and morphological diversity in Chesapeake Bay sediments. FEMS Microbiol Ecol 2011; 79:474-86. [DOI: 10.1111/j.1574-6941.2011.01238.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 09/12/2011] [Accepted: 10/17/2011] [Indexed: 02/07/2023] Open
Affiliation(s)
- Rebekah R. Helton
- Department of Plant and Soil Sciences; Delaware Biotechnology Institute; University of Delaware; Newark; DE; USA
| | - Kui Wang
- Center of Marine Biotechnology; University of Maryland Biotechnology Institute; Baltimore; MD; USA
| | - Jinjun Kan
- Department of Earth Sciences; University of Southern California; Los Angeles; CA; USA
| | - Deborah H. Powell
- Delaware Biotechnology Institute Bio-Imaging Center; Newark; DE; USA
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14
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Diversity and abundance of single-stranded DNA viruses in human feces. Appl Environ Microbiol 2011; 77:8062-70. [PMID: 21948823 DOI: 10.1128/aem.06331-11] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In this study, we investigated the abundance and diversity of single-stranded DNA (ssDNA) viruses in fecal samples from five healthy individuals through a combination of serial filtration and CsCl gradient ultracentrifugation. Virus abundance ranged from 10⁸ to 10⁹ per gram of feces, and virus-to-bacterium ratios were much lower (less than 0.1) than those observed in aquatic environments (5 to 10). Viral DNA was extracted and randomly amplified using phi29 polymerase and analyzed through high-throughput 454 pyrosequencing. Among 400,133 sequences, an average of 86.2% viromes were previously uncharacterized in public databases. Among previously known viruses, double-stranded DNA podophages (52 to 74%), siphophages (11 to 30%), myophages (1 to 4%), and ssDNA microphages (3 to 9%) were major constituents of human fecal viromes. A phylogenetic analysis of 24 large contigs of microphages based on conserved capsid protein sequences revealed five distinct newly discovered evolutionary microphage groups that were distantly related to previously known microphages. Moreover, putative capsid protein sequences of five contigs were closely related to prophage-like sequences in the genomes of three Bacteroides and three Prevotella strains, suggesting that Bacteroides and Prevotella are the sources of infecting microphages in their hosts.
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15
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Jeffries TC, Seymour JR, Gilbert JA, Dinsdale EA, Newton K, Leterme SSC, Roudnew B, Smith RJ, Seuront L, Mitchell JG. Substrate type determines metagenomic profiles from diverse chemical habitats. PLoS One 2011; 6:e25173. [PMID: 21966446 PMCID: PMC3179486 DOI: 10.1371/journal.pone.0025173] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 08/29/2011] [Indexed: 11/23/2022] Open
Abstract
Environmental parameters drive phenotypic and genotypic frequency variations in microbial communities and thus control the extent and structure of microbial diversity. We tested the extent to which microbial community composition changes are controlled by shifting physiochemical properties within a hypersaline lagoon. We sequenced four sediment metagenomes from the Coorong, South Australia from samples which varied in salinity by 99 Practical Salinity Units (PSU), an order of magnitude in ammonia concentration and two orders of magnitude in microbial abundance. Despite the marked divergence in environmental parameters observed between samples, hierarchical clustering of taxonomic and metabolic profiles of these metagenomes showed striking similarity between the samples (>89%). Comparison of these profiles to those derived from a wide variety of publically available datasets demonstrated that the Coorong sediment metagenomes were similar to other sediment, soil, biofilm and microbial mat samples regardless of salinity (>85% similarity). Overall, clustering of solid substrate and water metagenomes into discrete similarity groups based on functional potential indicated that the dichotomy between water and solid matrices is a fundamental determinant of community microbial metabolism that is not masked by salinity, nutrient concentration or microbial abundance.
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Affiliation(s)
- Thomas C Jeffries
- School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia.
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16
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Dumas MD, Polson SW, Ritter D, Ravel J, Gelb J, Morgan R, Wommack KE. Impacts of poultry house environment on poultry litter bacterial community composition. PLoS One 2011; 6:e24785. [PMID: 21949751 PMCID: PMC3174962 DOI: 10.1371/journal.pone.0024785] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Accepted: 08/17/2011] [Indexed: 11/25/2022] Open
Abstract
Viral and bacterial pathogens are a significant economic concern to the US broiler industry and the ecological epicenter for poultry pathogens is the mixture of bedding material, chicken excrement and feathers that comprises the litter of a poultry house. This study used high-throughput sequencing to assess the richness and diversity of poultry litter bacterial communities, and to look for connections between these communities and the environmental characteristics of a poultry house including its history of gangrenous dermatitis (GD). Cluster analysis of 16S rRNA gene sequences revealed differences in the distribution of bacterial phylotypes between Wet and Dry litter samples and between houses. Wet litter contained greater diversity with 90% of total bacterial abundance occurring within the top 214 OTU clusters. In contrast, only 50 clusters accounted for 90% of Dry litter bacterial abundance. The sixth largest OTU cluster across all samples classified as an Arcobacter sp., an emerging human pathogen, occurring in only the Wet litter samples of a house with a modern evaporative cooling system. Ironically, the primary pathogenic clostridial and staphylococcal species associated with GD were not found in any house; however, there were thirteen 16S rRNA gene phylotypes of mostly gram-positive phyla that were unique to GD-affected houses and primarily occurred in Wet litter samples. Overall, the poultry house environment appeared to substantially impact the composition of litter bacterial communities and may play a key role in the emergence of food-borne pathogens.
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Affiliation(s)
- Michael D. Dumas
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
| | - Shawn W. Polson
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
- Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, United States of America
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, United States of America
| | - Don Ritter
- Mountaire Farms Inc., Millsboro, Delaware, United States of America
| | - Jacques Ravel
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Jack Gelb
- Department of Animal and Food Sciences, University of Delaware, Newark, Delaware, United States of America
| | - Robin Morgan
- Department of Animal and Food Sciences, University of Delaware, Newark, Delaware, United States of America
| | - K. Eric Wommack
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware, United States of America
- Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, United States of America
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17
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Williamson KE, Helton RR, Wommack KE. Bias in bacteriophage morphological classification by transmission electron microscopy due to breakage or loss of tail structures. Microsc Res Tech 2011; 75:452-7. [PMID: 21919126 DOI: 10.1002/jemt.21077] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 07/30/2011] [Indexed: 11/06/2022]
Abstract
Virtually every study that has used transmission electron microscopy (TEM) to estimate viral diversity has acknowledged that loss of phage tails during sample preparation may have biased the results. However, the magnitude of this potential bias has yet to be constrained. To characterize biases in virus morphological diversity due to tail loss, six phage strains representing the order Caudovirales were inoculated into sterile sediments and soils. Phage particles were then extracted using standard methods. Morphologies of extracted phage particles were compared to those of unmanipulated control samples to determine the extent of tail breakage incurred by extraction procedures. Podoviruses exhibited the smallest frequency of tail loss during extraction (1.2-14%), myoviruses were moderately susceptible to tail breakage (15-40%), and siphoviruses were highly susceptible (32-76%). Thus, TEM assessments of viral diversity in soils or sediments by distribution of tail morphologies may be biased toward podoviruses and virions lacking tails, while simultaneously underestimating the abundance of siphoviruses. However, since the majority of viral capsids observed under TEM were intact, estimates of viral diversity based on the distribution of capsid diameters may provide a more reliable basis for morphological comparisons within and across ecosystems.
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Affiliation(s)
- Kurt E Williamson
- Department of Biology, College of William and Mary, Williamsburg, Virginia 23186, USA.
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18
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Repeating patterns of virioplankton production within an estuarine ecosystem. Proc Natl Acad Sci U S A 2011; 108:11506-11. [PMID: 21709214 DOI: 10.1073/pnas.1101907108] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Chesapeake Bay, a seasonally variable temperate estuary, provides a natural laboratory for examining the fluctuations and impacts of viral lysis on aquatic microorganisms. Viral abundance (VA) and viral production (VP) were monitored in the Chesapeake Bay over 4 1/2 annual cycles, producing a unique, long-term, interannual study of virioplankton production. High and dynamic VP rates, averaging 7.9 × 10(6) viruses per mL per h, indicate that viral lysis impacts a significant fraction of microorganisms in the Chesapeake. Viral-mediated bacterial mortality, VA, VP, and organic carbon release all displayed similar interannual and seasonal trends with higher values in 2003 and 2006 than in 2004 and 2005 and peaks in early spring and summer. Surprisingly, higher rates of viral lysis occurred in winter, resulting in a magnified effect of viral lysis on bacterioplankton during times of reduced productivity. Viral lysis directly impacted the organic carbon pool, contributing on average 76 μg of C per L per d, an amount capable of sustaining ∼55% of Chesapeake Bay bacterial production. The observed repeating interannual patterns of VP and lysis are likely interlinked with seasonal cycles of host abundance and diversity, which are in turn driven by annual cycles in environmental conditions, emphasizing the complex interplay of seasonality and microbial ecology in the Chesapeake Bay.
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19
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Del Casale A, Flanagan PV, Larkin MJ, Allen CC, Kulakov LA. Analysis of transduction in wastewater bacterial populations by targeting the phage-derived 16S rRNA gene sequences. FEMS Microbiol Ecol 2011; 76:100-8. [DOI: 10.1111/j.1574-6941.2010.01034.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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20
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Determination of viral production in aquatic sediments using the dilution-based approach. Nat Protoc 2009; 4:1013-22. [PMID: 19536269 DOI: 10.1038/nprot.2009.82] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Viruses are the most abundant and dynamic biological entities in the world's ecosystems. Marine sediments, the largest biome in the world, have the potential to represent an optimal environment for viral development. To assess the viral effect on their hosts, and to understand the ecological role of the viruses in the benthic food webs and biogeochemical cycles, measurements of benthic viral production are needed. Different direct and indirect approaches have been proposed to estimate viral production in aquatic sediments, but a standardized protocol is not available yet. The method presented in this protocol relies on the short-time incubations of sediment samples with virus-free seawater, and the subsequent determination of the increase in viral abundance over time by epifluorescence microscopy. The protocol described here is highly reliable, inexpensive and easy to use. The entire procedure takes approximately 3 days to be completed, but the method allows the parallel processing of several sediment samples, which is recommended in ecological studies.
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21
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Seasonal dynamics and metagenomic characterization of estuarine viriobenthos assemblages by randomly amplified polymorphic DNA PCR. Appl Environ Microbiol 2009; 75:2259-65. [PMID: 19218408 DOI: 10.1128/aem.02551-08] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Direct enumeration and genetic analyses indicate that aquatic sediments harbor abundant and diverse viral communities. Thus far, synecological analysis of estuarine sediment viral diversity over an annual cycle has not been reported. This oversight is due in large part to a lack of molecular genetic approaches for assessing viral diversity within a large collection of environmental samples. Here, randomly amplified polymorphic DNA PCR (RAPD-PCR) was used to examine viral genotypic diversity within Chesapeake Bay sediments. Using a single 10-mer oligonucleotide primer for all samples, RAPD-PCR analysis of sediment viral assemblages yielded unique banding patterns across spatial and temporal scales, with the occurrence of specific bands varying among the sample set. Cluster analysis of RAPD-PCR amplicon banding patterns indicated that sediment viral assemblages changed with season and to a lesser extent with geographic location. Sequence analysis of RAPD-PCR amplicons revealed that 76% of sediment viral sequences were not homologous to any sequence in the GenBank nonredundant protein database. Of the GenBank sequence homologs, the majority belonged to viruses within the Podoviridae (24%) and Myoviridae (22%) viral families, which agrees with the previously observed frequencies of these morphological families in Chesapeake Bay sediments. Furthermore, the majority of the sediment viral sequences homologous to GenBank nonredundant protein sequences were phages or prophages (57%). Hence, RAPD-PCR proved to be a reliable and useful approach for characterization of viral assemblages and the genetic diversity of viruses within aquatic sediments.
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22
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Wommack KE, Williamson KE, Helton RR, Bench SR, Winget DM. Methods for the isolation of viruses from environmental samples. Methods Mol Biol 2009; 501:3-14. [PMID: 19066805 DOI: 10.1007/978-1-60327-164-6_1] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Viruses are omnipresent and extraordinarily abundant in the microbial ecosystems of water, soil, and sediment. In nearly every reported case for aquatic and porous media environments (soils and sediments) viral abundance exceeds that of co-occurring host populations by 10-100-fold. If current estimates based on metagenome DNA sequence data are correct, then viruses represent the largest reservoir of unknown genetic diversity on Earth. Microscopy and molecular genetic tools have been critical in demonstrating that viruses are a dynamic component of microbial ecosystems capable of significantly influencing the productivity and population biology of their host communities. Moreover, these approaches have begun to describe and constrain the immense genetic diversity of viral communities. A critical first step in the application of many cultivation-independent approaches to virus ecology is obtaining a concentrate of viruses from an environmental sample. Culture-dependent methods also rely on viruses being present at a high enough abundance to detect. Here, methodological details for the isolation and concentration of viruses from water, soil, and aquatic sediment samples are covered in detail.
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Affiliation(s)
- K Eric Wommack
- Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA
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23
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Major viral impact on the functioning of benthic deep-sea ecosystems. Nature 2008; 454:1084-7. [PMID: 18756250 DOI: 10.1038/nature07268] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 07/15/2008] [Indexed: 11/09/2022]
Abstract
Viruses are the most abundant biological organisms of the world's oceans. Viral infections are a substantial source of mortality in a range of organisms-including autotrophic and heterotrophic plankton-but their impact on the deep ocean and benthic biosphere is completely unknown. Here we report that viral production in deep-sea benthic ecosystems worldwide is extremely high, and that viral infections are responsible for the abatement of 80% of prokaryotic heterotrophic production. Virus-induced prokaryotic mortality increases with increasing water depth, and beneath a depth of 1,000 m nearly all of the prokaryotic heterotrophic production is transformed into organic detritus. The viral shunt, releasing on a global scale approximately 0.37-0.63 gigatonnes of carbon per year, is an essential source of labile organic detritus in the deep-sea ecosystems. This process sustains a high prokaryotic biomass and provides an important contribution to prokaryotic metabolism, allowing the system to cope with the severe organic resource limitation of deep-sea ecosystems. Our results indicate that viruses have an important role in global biogeochemical cycles, in deep-sea metabolism and the overall functioning of the largest ecosystem of our biosphere.
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Manini E, Luna GM, Corinaldesi C, Zeppilli D, Bortoluzzi G, Caramanna G, Raffa F, Danovaro R. Prokaryote diversity and virus abundance in shallow hydrothermal vents of the Mediterranean Sea (Panarea Island) and the Pacific Ocean (north Sulawesi-Indonesia). MICROBIAL ECOLOGY 2008; 55:626-39. [PMID: 17687593 DOI: 10.1007/s00248-007-9306-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 07/13/2007] [Accepted: 07/15/2007] [Indexed: 05/16/2023]
Abstract
Despite their ubiquitous distribution in tectonically active coastal zones, shallow water hydrothermal vents have been less investigated than deep-sea vents. In the present study, we investigated the role of viral control and fluid emissions on prokaryote abundance, diversity, and community structure (total Archaea, total Bacteria, and sulphate-reducing bacteria) in waters and sediments surrounding the caldera of four different shallow-water hydrothermal vents (three located in the Mediterranean Sea and one in the Pacific Ocean). All vents, independent of their location, generally displayed a significant decrease of benthic prokaryote abundance, as well as its viable fraction, with increasing distance from the vent. Prokaryote assemblages were always dominated by Bacteria. Benthic Archaea accounted for 23-33% of total prokaryote abundance in the Mediterranean Sea and from 13 to 29% in the Pacific Ocean, whereas in the water column they accounted for 25-38%. The highest benthic bacterial ribotype richness was observed in close proximity of the vents (i.e., at 10-cm distance from the emissions), indicating that vent fluids might influence bacterial diversity in surrounding sediments. Virioplankton and viriobenthos abundances were low compared to other marine systems, suggesting that temperature and physical-chemical conditions might influence viral survival in these vent systems. We thus hypothesize that the high bacterial diversity observed in close proximity of the vents is related with the highly variable vent emissions, which could favor the coexistence of several prokaryotic species.
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Affiliation(s)
- E Manini
- Institute of Marine Science, ISMAR-CNR, Largo Fiera della Pesca, 60125 Ancona, Italy
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25
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Danovaro R, Bongiorni L, Corinaldesi C, Giovannelli D, Damiani E, Astolfi P, Greci L, Pusceddu A. Sunscreens cause coral bleaching by promoting viral infections. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:441-7. [PMID: 18414624 PMCID: PMC2291018 DOI: 10.1289/ehp.10966] [Citation(s) in RCA: 300] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Accepted: 01/03/2008] [Indexed: 05/22/2023]
Abstract
BACKGROUND Coral bleaching (i.e., the release of coral symbiotic zooxanthellae) has negative impacts on biodiversity and functioning of reef ecosystems and their production of goods and services. This increasing world-wide phenomenon is associated with temperature anomalies, high irradiance, pollution, and bacterial diseases. Recently, it has been demonstrated that personal care products, including sunscreens, have an impact on aquatic organisms similar to that of other contaminants. OBJECTIVES Our goal was to evaluate the potential impact of sunscreen ingredients on hard corals and their symbiotic algae. METHODS In situ and laboratory experiments were conducted in several tropical regions (the Atlantic, Indian, and Pacific Oceans, and the Red Sea) by supplementing coral branches with aliquots of sunscreens and common ultraviolet filters contained in sunscreen formula. Zooxanthellae were checked for viral infection by epifluorescence and transmission electron microscopy analyses. RESULTS Sunscreens cause the rapid and complete bleaching of hard corals, even at extremely low concentrations. The effect of sunscreens is due to organic ultraviolet filters, which are able to induce the lytic viral cycle in symbiotic zooxanthellae with latent infections. CONCLUSIONS We conclude that sunscreens, by promoting viral infection, potentially play an important role in coral bleaching in areas prone to high levels of recreational use by humans.
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Affiliation(s)
- Roberto Danovaro
- Department of Marine Sciences, Faculty of Science, Polytechnic University of the Marche, Via Brecce Bianche, 60131 Ancona, Italy.
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Abstract
Viruses are by far the most abundant 'lifeforms' in the oceans and are the reservoir of most of the genetic diversity in the sea. The estimated 10(30) viruses in the ocean, if stretched end to end, would span farther than the nearest 60 galaxies. Every second, approximately 10(23) viral infections occur in the ocean. These infections are a major source of mortality, and cause disease in a range of organisms, from shrimp to whales. As a result, viruses influence the composition of marine communities and are a major force behind biogeochemical cycles. Each infection has the potential to introduce new genetic information into an organism or progeny virus, thereby driving the evolution of both host and viral assemblages. Probing this vast reservoir of genetic and biological diversity continues to yield exciting discoveries.
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Affiliation(s)
- Curtis A Suttle
- University of British Columbia, Departments of Earth and Ocean Sciences, Botany, and Microbiology and Immunology, 1461 BioSciences, 6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada.
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