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Tian J, Wang H, Huan P, Yue X, Liu B. Comprehensive Multi-omics Approaches Provide Insights to Summer Mortality in the Clam Meretrix petechialis. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2024; 26:389-403. [PMID: 38483672 DOI: 10.1007/s10126-024-10304-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 03/06/2024] [Indexed: 04/25/2024]
Abstract
Bivalve mass mortalities have been reported worldwide, which not only can be explained as a result of pathogen infection, but may reflect changes in environments. Although these episodes were often reported, there was limited information concerning the molecular responses to various stressors leading to summer mortality. In the present work, RNA sequencing (RNA-seq), tandem mass tagging (TMT)-based quantitative proteomics, and 16S rRNA sequencing were used to explore the natural outbreak of summer mortality in the clam Meretrix petechialis. We identified a total of 172 differentially expressed genes (DEGs) and 222 differentially expressed proteins (DEPs) in the diseased group compared to the normal group. The inconsistent expression profiles of immune DEGs/DEPs may be due to the immune dysregulation of the diseased clams. Notably, 11 solute carrier family genes were found among the top 20 down-regulated genes in the diseased group, indicating that weakened transmembrane transport ability might occur in the diseased clams. Integration analysis of transcriptomic and proteomic results showed that many metabolic processes such as "arginine and proline metabolism" and "tyrosine metabolism" were inhibited in the diseased group, suggesting metabolic inhibition. Moreover, 16S rRNA sequencing revealed that the microbial composition of clam hepatopancreas was disordered in the diseased group. The comparison of DEGs expression between the natural summer mortality event and an artificial challenge experiment involving both Vibrio infection and heat stress revealed 9/15 genes showing similar expression trends between the two conditions, suggesting that the summer mortality might be caused by a combination of high temperature and Vibrio infection. These results would deepen our understanding of summer mortality and provide candidate resistance markers for clam resistance breeding.
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Affiliation(s)
- Jing Tian
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hongxia Wang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266000, China
| | - Pin Huan
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266000, China
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Xin Yue
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266000, China
| | - Baozhong Liu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266000, China.
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Chinese Academy of Sciences, Qingdao, 266071, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Moloney BJ, Deveney M, Ellard K, Hick P, Kirkland PD, Moody N, Frances J. Ostreid herpesvirus-1 microvariant surveillance in Pacific oysters (Magallana gigas, Thunberg, 1793) in Australia in 2011. Aust Vet J 2023; 101:345-355. [PMID: 37421375 DOI: 10.1111/avj.13265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 05/12/2023] [Accepted: 06/14/2023] [Indexed: 07/10/2023]
Abstract
OBJECTIVE To demonstrate that OsHV-1 microvariant was limited to the known infected areas in New South Wales at the time of the survey in 2011. DESIGN A 2-stage survey to demonstrate probability of infection at 2% design prevalence within oyster growing regions and to detect at least one infected region (4% design prevalence) with 95% confidence. SAMPLE POPULATION Magallana gigas in nominated oyster growing regions in New South Wales, South Australia and Tasmania as approved by the Aquatic Consultative Committee on Emergency Animal Diseases and documented in a national surveillance plan. PROCEDURE Field sampling for active surveillance and laboratory selection of appropriate tissues using methods to minimize potential for cross contamination. Published methods for qPCR and conventional PCR for OsHV-1 microvariant. Stochastic analysis of survey results to demonstrate probability of detection in the areas tested. RESULTS AND CONCLUSIONS OsHV-1 microvariant was not detected in a total 4121 samples according to the case definition developed for the survey. However, in NSW a screening qPCR for OsHV-1 detected 13 samples that reacted. These samples were negative at 2 laboratories in the qPCR and conventional PCR assays used in the case definition for the survey. We concluded that oyster production areas of Australia outside the infected area in NSW met the criteria for self-declaration of freedom at the time of the survey in 2011. CLINICAL RELEVANCE This activity illustrated achievements in surveillance for an emerging emergency animal pathogen where epidemiological and test validation data were limited, but where data was required to inform the emergency disease response. It also illustrated the challenges faced by investigators in interpreting surveillance results using tests with limited validation. It was guided by and has informed improvements in surveillance and emergency disease preparedness.
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Affiliation(s)
- B J Moloney
- NSW Department of Primary Industries, Head Office, Orange, New South Wales, Australia
| | - M Deveney
- South Australian Research and Development Institute, SARDI Aquatic Sciences, West Beach, South Australia, Australia
| | - K Ellard
- Biosecurity Tasmania, Department of Natural Resources and the Environment, Hobart, Tasmania, Australia
| | - P Hick
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales, Australia
| | - P D Kirkland
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales, Australia
| | - Njg Moody
- CSIRO, Australian Centre for Disease Preparedness, Geelong, Victoria, Australia
| | - J Frances
- NSW Department of Primary Industries, Port Stephens Fisheries Institute, Port Stephens, New South Wales, Australia
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Worden PJ, Bogema DR, Micallef ML, Go J, Deutscher AT, Labbate M, Green TJ, King WL, Liu M, Seymour JR, Jenkins C. Phylogenomic diversity of Vibrio species and other Gammaproteobacteria isolated from Pacific oysters ( Crassostrea gigas) during a summer mortality outbreak. Microb Genom 2022; 8:mgen000883. [PMID: 36748707 PMCID: PMC9837568 DOI: 10.1099/mgen.0.000883] [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] [Indexed: 12/12/2022] Open
Abstract
The Pacific oyster (PO), Crassostrea gigas, is an important commercial marine species but periodically experiences large stock losses due to disease events known as summer mortality. Summer mortality has been linked to environmental perturbations and numerous viral and bacterial agents, indicating this disease is multifactorial in nature. In 2013 and 2014, several summer mortality events occurred within the Port Stephens estuary (NSW, Australia). Extensive culture and molecular-based investigations were undertaken and several potentially pathogenic Vibrio species were identified. To improve species identification and genomically characterise isolates obtained from this outbreak, whole-genome sequencing (WGS) and subsequent genomic analyses were performed on 48 bacterial isolates, as well as a further nine isolates from other summer mortality studies using the same batch of juveniles. Average nucleotide identity (ANI) identified most isolates to the species level and included members of the Photobacterium, Pseudoalteromonas, Shewanella and Vibrio genera, with Vibrio species making up more than two-thirds of all species identified. Construction of a phylogenomic tree, ANI analysis, and pan-genome analysis of the 57 isolates represents the most comprehensive culture-based phylogenomic survey of Vibrios during a PO summer mortality event in Australian waters and revealed large genomic diversity in many of the identified species. Our analysis revealed limited and inconsistent associations between isolate species and their geographical origins, or host health status. Together with ANI and pan-genome results, these inconsistencies suggest that to determine the role that microbes may have in Pacific oyster summer mortality events, isolate identification must be at the taxonomic level of strain. Our WGS data (specifically, the accessory genomes) differentiated bacterial strains, and coupled with associated metadata, highlight the possibility of predicting a strain's environmental niche and level of pathogenicity.
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Affiliation(s)
- Paul J. Worden
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Woodbridge Rd, Menangle, NSW 2568
| | - Daniel R. Bogema
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Woodbridge Rd, Menangle, NSW 2568
| | - Melinda L. Micallef
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Woodbridge Rd, Menangle, NSW 2568
| | - Jeffrey Go
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Woodbridge Rd, Menangle, NSW 2568
| | - Ania T. Deutscher
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Woodbridge Rd, Menangle, NSW 2568
| | - Maurizio Labbate
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Timothy J. Green
- Centre for Shellfish Research, Vancouver Island University, Nanaimo, British Columbia,, Canada
| | - William L. King
- Department of Plant Pathology and Environmental MIcrobiology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Michael Liu
- iThree Institute, University of Technology Sydney, Building 4, 745 Harris Street, Broadway, Ultimo, NSW, 2007
| | - Justin R. Seymour
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007
| | - Cheryl Jenkins
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Woodbridge Rd, Menangle, NSW 2568,*Correspondence: Cheryl Jenkins,
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Fuller AM, VanBlaricom GR, Neuman MJ, Witting DA, Friedman CS. A field sentinel study investigating withering syndrome transmission dynamics in California abalones. MARINE ENVIRONMENTAL RESEARCH 2022; 173:105540. [PMID: 34864337 DOI: 10.1016/j.marenvres.2021.105540] [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: 05/27/2021] [Revised: 11/24/2021] [Accepted: 11/26/2021] [Indexed: 06/13/2023]
Abstract
We examined the risk of withering syndrome (WS) rickettsia-like organism (WS-RLO) infection in sentinel red abalone (Haliotis rufescens) deployed in modules at two Southern California field sites, one adjacent to an abalone farm and one adjacent to wild abalones. WS-RLO DNA was detected in seawater near modules at the wild abalone site but not near the farm (WS-RLO DNA was detected in the farm effluent). More WS-RLO DNA was detected in tissue from abalone near the farm relative to those near wild abalones (p < 0.05). However, infection prevalence and intensity based on histology were low and similar between sites (p > 0.05) and were independent of WS-RLO DNA loads in abalone tissue and seawater. More stippled (ST)-RLO than WS-RLO were observed with more ST-RLO infections near wild abalone than near the abalone farm (p < 0.05). We demonstrate the utility of caged sentinel abalone to better understand pathogen transmission patterns in the field.
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Affiliation(s)
- Ava M Fuller
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA, 98195, USA.
| | - Glenn R VanBlaricom
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA, 98195, USA; US Geological Survey, Washington Cooperative Fish and Wildlife Research Unit, University of Washington, Box 355020, Seattle, WA, 98195, USA
| | - Melissa J Neuman
- NOAA National Marine Fisheries Service Protected Resources Division, 501 West Ocean Blvd, Suite 4200 Long Beach, CA, 90802, USA
| | - David A Witting
- NOAA National Marine Fisheries Service Protected Resources Division, 501 West Ocean Blvd, Suite 4200 Long Beach, CA, 90802, USA
| | - Carolyn S Friedman
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA, 98195, USA
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Gustafson LL, Arzul I, Burge CA, Carnegie RB, Caceres-Martinez J, Creekmore L, Dewey W, Elston R, Friedman CS, Hick P, Hudson K, Lupo C, Rheault R, Spiegel K, Vásquez-Yeomans R. Optimizing surveillance for early disease detection: Expert guidance for Ostreid herpesvirus surveillance design and system sensitivity calculation. Prev Vet Med 2021; 194:105419. [PMID: 34274864 DOI: 10.1016/j.prevetmed.2021.105419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/22/2021] [Accepted: 06/26/2021] [Indexed: 10/21/2022]
Abstract
To keep pace with rising opportunities for disease emergence and spread, surveillance in aquaculture must enable the early detection of both known and new pathogens. Conventional surveillance systems (designed to provide proof of disease freedom) may not support detection outside of periodic sampling windows, leaving substantial blind spots to pathogens that emerge in other times and places. To address this problem, we organized an expert panel to envision optimal systems for early disease detection, focusing on Ostreid herpesvirus 1 (OsHV-1), a pathogen of panzootic consequence to oyster industries. The panel followed an integrative group process to identify and weight surveillance system traits perceived as critical to the early detection of OsHV-1. Results offer a road map with fourteen factors to consider when building surveillance systems geared to early detection; factor weights can be used by planners and analysts to compare the relative value of different designs or enhancements. The results were also used to build a simple, but replicable, model estimating the system sensitivity (SSe) of observational surveillance and, in turn, the confidence in disease freedom that negative reporting can provide. Findings suggest that optimally designed observational systems can contribute substantially to both early detection and disease freedom confidence. In contrast, active surveillance as a singular system is likely insufficient for early detection. The strongest systems combined active with observational surveillance and engaged joint industry and government involvement: results suggest that effective partnerships can generate highly sensitive systems, whereas ineffective partnerships may seriously erode early detection capability. Given the costs of routine testing, and the value (via averted losses) of early detection, we conclude that observational surveillance is an important and potentially very effective tool for health management and disease prevention on oyster farms, but one that demands careful planning and participation. This evaluation centered on OsHV-1 detection in farmed oyster populations. However, many of the features likely generalize to other pathogens and settings, with the important caveat that the pathogens need to manifest via morbidity or mortality events in the species, life stages and environments under observation.
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Affiliation(s)
- Lori L Gustafson
- Animal and Plant Health Inspection Services, U.S. Department of Agriculture, 2150 Centre Ave, Fort Collins, CO, 80526, USA.
| | - Isabelle Arzul
- Laboratoire de Genetique et Pathologie des Mollusques Marins, Ifremer, SG2M-LGPMM, Avenue de Mus de Loup, La Tremblade, 17390, France
| | - Colleen A Burge
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, 701 E Pratt Street, Baltimore, MD, 21202, USA
| | - Ryan B Carnegie
- Virginia Institute of Marine Science, William & Mary, P.O. Box 1346, Gloucester Point, VA, 23062, USA
| | - Jorge Caceres-Martinez
- Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Carretera Ensenada-Tijuana No. 3918, Zona Playitas, Ensenada, Baja California, 22860, Mexico
| | - Lynn Creekmore
- Animal and Plant Health Inspection Services, U.S. Department of Agriculture, 2150 Centre Ave, Fort Collins, CO, 80526, USA
| | - William Dewey
- Taylor Shellfish Farms, 130 SE Lynch Rd., Shelton, WA, 98584, USA
| | - Ralph Elston
- AquaTechnics Inc. PO Box 687, Carlsborg, WA, 98324, USA
| | - Carolyn S Friedman
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA, 98195, USA
| | - Paul Hick
- Sydney School of Veterinary Science, 425 Werombi Road, Camden, New South Wales, 2570, Australia
| | - Karen Hudson
- Virginia Institute of Marine Science, William & Mary, P.O. Box 1346, Gloucester Point, VA, 23062, USA
| | - Coralie Lupo
- Laboratoire de Genetique et Pathologie des Mollusques Marins, Ifremer, SG2M-LGPMM, Avenue de Mus de Loup, La Tremblade, 17390, France
| | - Robert Rheault
- East Coast Shellfish Growers Association, 1121 Mooresfield Rd., Wakefield, RI, 02879, USA
| | - Kevin Spiegel
- Animal and Plant Health Inspection Services, U.S. Department of Agriculture, 2150 Centre Ave, Fort Collins, CO, 80526, USA
| | - Rebeca Vásquez-Yeomans
- Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Carretera Ensenada-Tijuana No. 3918, Zona Playitas, Ensenada, Baja California, 22860, Mexico
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Dégremont L, Morga B, Maurouard E, Travers MA. Susceptibility variation to the main pathogens of Crassostrea gigas at the larval, spat and juvenile stages using unselected and selected oysters to OsHV-1 and/or V. aestuarianus. J Invertebr Pathol 2021; 183:107601. [PMID: 33964304 DOI: 10.1016/j.jip.2021.107601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 04/15/2021] [Accepted: 04/25/2021] [Indexed: 10/21/2022]
Abstract
French commercial hatcheries are massively producing Crassostrea gigas selected for their higher resistance to OsHV-1, and soon should also implement selection for increasing resistance to Vibrio aestuarianus. The first objective of this study was to optimize the breeding programs for dual resistance to OsHV-1 and V. aestuarianus to determine the earliest life stage for which oysters are able to develop disease resistance. Wild stocks and selected families were tested using experimental infections by both pathogens at the larval, spat and juvenile stages. Oyster families could be evaluated for OsHV-1 as soon as the larval stage by a bath method, but this only highlighted the most resistant families; those that showed the highest resistance to V. aestuarianus could be determined using the cohabitation method at the juvenile stage. The second objective of this study was to determine if selection to increase/decrease the resistance to OsHV-1 and V. aestuarianus could have an impact on other major pathogens currently detected in hatchery at the larval stage, and in nursery and field at the spat/juveniles stages (V. coralliilyticus, V. crassostreae, V. tasmaniensis, V. neptunius, V. europaeus, V. harveyi, V. chagasi). No relationship was found between mortality caused by V. aestuarianus/OsHV-1 and the mortality caused by the other virulent bacterial strains tested regardless the stages, except between OsHV-1 and V. tasmaniensis at the juvenile stage. Finally, miscellaneous findings were evidenced such as (1) bath for bacterial challenges was not adapted for spat, (2) the main pathogens at the larval stage were OsHV-1 and V. coralliilyticus using bath, while it was V. coralliilyticus, V. europaeus, and V. neptunius at the juvenile stage by injection, and (4) variation in mortality was observed among families/wild controls for all pathogens at larval and juvenile stages, except for V. harveyi for larvae.
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Affiliation(s)
| | | | | | - Marie-Agnès Travers
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, F-34090 Montpellier, France
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Whittington RJ, Hick P, Fuhrmann M, Liu O, Paul-Pont I. Removal of oyster pathogens from seawater. ENVIRONMENT INTERNATIONAL 2021; 150:106258. [PMID: 33243468 DOI: 10.1016/j.envint.2020.106258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/30/2020] [Accepted: 10/31/2020] [Indexed: 06/11/2023]
Affiliation(s)
- R J Whittington
- School of Veterinary Science, The University of Sydney, Camden, NSW 2570, Australia.
| | - P Hick
- School of Veterinary Science, The University of Sydney, Camden, NSW 2570, Australia
| | - M Fuhrmann
- School of Veterinary Science, The University of Sydney, Camden, NSW 2570, Australia
| | - O Liu
- School of Veterinary Science, The University of Sydney, Camden, NSW 2570, Australia; Aquatic Pest and Health Policy, Animal Health Policy Branch, Biosecurity Animal Division, Australian Government Department of Agriculture, Water and the Environment, Canberra, ACT 2601, Australia(1)
| | - I Paul-Pont
- School of Veterinary Science, The University of Sydney, Camden, NSW 2570, Australia; Laboratoire des Sciences de l'Environnement Marin (LEMAR), CNRS/UBO/IRD/IFREMER Institut Universitaire Europeen de la Mer, 29280 Plouzane, France(1)
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Prado-Alvarez M, García-Fernández P, Faury N, Azevedo C, Morga B, Gestal C. First detection of OsHV-1 in the cephalopod Octopus vulgaris. Is the octopus a dead-end for OsHV-1? J Invertebr Pathol 2021; 183:107553. [PMID: 33596434 DOI: 10.1016/j.jip.2021.107553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/28/2021] [Accepted: 02/09/2021] [Indexed: 11/29/2022]
Abstract
The ostreid herpes virus (OsHV-1), associated with massive mortalities in the bivalve Crassostrea gigas, was detected for the first time in the cephalopod Octopus vulgaris. Wild adult animals from a natural breeding area in Spain showed an overall prevalence of detection of 87.5% between 2010 and 2015 suggesting an environmental source of viral material uptake. Overall positive PCR detections were significantly higher in adult animals (p = 0.031) compared to newly hatched paralarvae (62%). Prevalence in embryos reached 65%. Sequencing of positive amplicons revealed a match with the variant OsHV-1 µVar showing the genomic features that distinguish this variant in the ORF4. Gill tissues from adult animals were also processed for in situ hybridization and revealed positive labelling. Experimental exposure trials in octopus paralarvae were carried out by cohabitation with virus injected oysters and by immersion in viral suspension observing a significant decrease in paralarval survival in both experiments. An increase in the number of OsHV-1 positive animals was detected in dead paralarvae after cohabitation with virus injected oysters. No signs of viral replication were observed based on lack of viral gene expression or visualization of viral structures by transmission electron microscopy. The octopus response against OsHV-1 was evaluated by gene expression of previously reported transcripts involved in immune response in C. gigas suggesting that immune defences in octopus are also activated after exposure to OsHV-1.
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Affiliation(s)
- Maria Prado-Alvarez
- Marine Molecular Pathobiology Group, Marine Research Institute, Spanish National Research Council, Eduardo Cabello 6, 36208 Vigo, Spain.
| | - Pablo García-Fernández
- Marine Molecular Pathobiology Group, Marine Research Institute, Spanish National Research Council, Eduardo Cabello 6, 36208 Vigo, Spain
| | - Nicole Faury
- IFREMER, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390 La Tremblade, France
| | - Carlos Azevedo
- Interdisciplinary Center of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal; Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Benjamin Morga
- IFREMER, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390 La Tremblade, France
| | - Camino Gestal
- Marine Molecular Pathobiology Group, Marine Research Institute, Spanish National Research Council, Eduardo Cabello 6, 36208 Vigo, Spain.
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Agnew MV, Friedman CS, Langdon C, Divilov K, Schoolfield B, Morga B, Degremont L, Dhar AK, Kirkland P, Dumbauld B, Burge CA. Differential Mortality and High Viral Load in Naive Pacific Oyster Families Exposed to OsHV-1 Suggests Tolerance Rather than Resistance to Infection. Pathogens 2020; 9:E1057. [PMID: 33348814 PMCID: PMC7766980 DOI: 10.3390/pathogens9121057] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 11/25/2022] Open
Abstract
Pacific oysters, Crassostrea gigas, are one of the most productive aquaculture species in the world. However, they are threatened by the spread of Ostreid herpesvirus-1 (OsHV-1) and its microvariants (collectively "µvars"), which cause mass mortalities in all life stages of Pacific oysters globally. Breeding programs have been successful in reducing mortality due to OsHV-1 variants following viral outbreaks; however, an OsHV-1-resistant oyster line does not yet exist in the United States (US), and it is unknown how OsHV-1 µvars will affect US oyster populations compared to the current variant, which is similar to the OsHV-1 reference, found in Tomales Bay, CA. The goals of this study were to investigate the resistance of C. gigas juveniles produced by the Molluscan Broodstock Program (MBP) to three variants of OsHV-1: a California reference OsHV-1, an Australian µvar, and a French µvar. This is the first study to directly compare OsHV-1 µvars to a non-µvar. The survival probability of oysters exposed to the French (FRA) or Australian (AUS) µvar was significantly lower (43% and 71%, respectively) than to the reference variant and controls (96%). No oyster family demonstrated resistance to all three OsHV-1 variants, and many surviving oysters contained high copy numbers of viral DNA (mean ~3.53 × 108). These results indicate that the introduction of OsHV-1 µvars could have substantial effects on US Pacific oyster aquaculture if truly resistant lines are not achieved, and highlight the need to consider resistance to infection in addition to survival as traits in breeding programs to reduce the risk of the spread of OsHV-1 variants.
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Affiliation(s)
- M. Victoria Agnew
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD 21202, USA;
| | - Carolyn S. Friedman
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA;
| | - Christopher Langdon
- Department of Fisheries and Wildlife, Coastal Oregon Marine Experiment Station, Hatfield Marine Science Center, Newport, OR 97365, USA; (C.L.); (K.D.); (B.S.)
| | - Konstantin Divilov
- Department of Fisheries and Wildlife, Coastal Oregon Marine Experiment Station, Hatfield Marine Science Center, Newport, OR 97365, USA; (C.L.); (K.D.); (B.S.)
| | - Blaine Schoolfield
- Department of Fisheries and Wildlife, Coastal Oregon Marine Experiment Station, Hatfield Marine Science Center, Newport, OR 97365, USA; (C.L.); (K.D.); (B.S.)
| | - Benjamin Morga
- Ifremer, SG2M, LGPMM, 17390 La Tremblade, France; (B.M.); (L.D.)
| | - Lionel Degremont
- Ifremer, SG2M, LGPMM, 17390 La Tremblade, France; (B.M.); (L.D.)
| | - Arun K. Dhar
- Aquaculture Pathology Laboratory, School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA;
| | - Peter Kirkland
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, NSW 2568, Australia;
| | - Brett Dumbauld
- Hatfield Marine Science Center, USDA-ARS, Newport, OR 97365, USA;
| | - Colleen A. Burge
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD 21202, USA;
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King WL, Siboni N, Kahlke T, Dove M, O'Connor W, Mahbub KR, Jenkins C, Seymour JR, Labbate M. Regional and oyster microenvironmental scale heterogeneity in the Pacific oyster bacterial community. FEMS Microbiol Ecol 2020; 96:5813259. [PMID: 32221598 DOI: 10.1093/femsec/fiaa054] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 03/22/2020] [Indexed: 01/04/2023] Open
Abstract
Different organs of a host represent distinct microenvironments resulting in the establishment of multiple discrete bacterial communities within a host. These discrete bacterial communities can also vary according to geographical location. For the Pacific oyster, Crassostrea gigas, the factors governing bacterial diversity and abundance of different oyster microenvironments are poorly understood. In this study, the factors shaping bacterial abundance, diversity and composition associated with the C. gigas mantle, gill, adductor muscle and digestive gland were characterised using 16S (V3-V4) rRNA amplicon sequencing across six discrete estuaries. Both location and tissue-type, with tissue-type being the stronger determinant, were factors driving bacterial community composition. Bacterial communities from wave-dominated estuaries had similar compositions and higher bacterial abundance despite being geographically distant from one another, possibly indicating that functional estuarine morphology characteristics are a factor shaping the oyster bacterial community. Despite the bacterial community heterogeneity, examinations of the core bacterial community identified Spirochaetaceae bacteria as conserved across all sites and samples. Whereas members of the Vulcaniibacterium, Spirochaetaceae and Margulisbacteria, and Polynucleobacter were regionally conserved members of the digestive gland, gill and mantle bacterial communities, respectively. This indicates that baseline bacterial community profiles for specific locations are necessary when investigating bacterial communities in oyster health.
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Affiliation(s)
- William L King
- University of Technology Sydney, The School of Life Sciences, Ultimo, New South Wales, 2007, Australia.,University of Technology Sydney, Climate Change Cluster, Ultimo, New South Wales, 2007, Australia
| | - Nachshon Siboni
- University of Technology Sydney, Climate Change Cluster, Ultimo, New South Wales, 2007, Australia
| | - Tim Kahlke
- University of Technology Sydney, Climate Change Cluster, Ultimo, New South Wales, 2007, Australia
| | - Michael Dove
- NSW Department of Primary Industries, Port Stephens Fisheries Institute, Port Stephens, New South Wales, 2316, Australia
| | - Wayne O'Connor
- NSW Department of Primary Industries, Port Stephens Fisheries Institute, Port Stephens, New South Wales, 2316, Australia
| | - Khandaker Rayhan Mahbub
- University of Technology Sydney, The School of Life Sciences, Ultimo, New South Wales, 2007, Australia
| | - Cheryl Jenkins
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales, 2568, Australia
| | - Justin R Seymour
- University of Technology Sydney, Climate Change Cluster, Ultimo, New South Wales, 2007, Australia
| | - Maurizio Labbate
- University of Technology Sydney, The School of Life Sciences, Ultimo, New South Wales, 2007, Australia
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11
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Friedman CS, Reece KS, Wippel BJT, Agnew MV, Dégremont L, Dhar AK, Kirkland P, MacIntyre A, Morga B, Robison C, Burge CA. Unraveling concordant and varying responses of oyster species to Ostreid Herpesvirus 1 variants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 739:139752. [PMID: 32846506 DOI: 10.1016/j.scitotenv.2020.139752] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 05/12/2020] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
The Ostreid herpesvirus 1 (OsHV-1) and variants, particularly the microvariants (μVars), are virulent and economically devastating viruses impacting oysters. Since 2008 OsHV-1 μVars have emerged rapidly having particularly damaging effects on aquaculture industries in Europe, Australia and New Zealand. We conducted field trials in Tomales Bay (TB), California where a non-μVar strain of OsHV-1 is established and demonstrated differential mortality of naturally exposed seed of three stocks of Pacific oyster, Crassostrea gigas, and one stock of Kumamoto oyster, C. sikamea. Oysters exposed in the field experienced differential mortality that ranged from 64 to 99% in Pacific oysters (Tasmania>Midori = Willapa stocks), which was much higher than that of Kumamoto oysters (25%). Injection trials were done using French (FRA) and Australian (AUS) μVars with the same oyster stocks as planted in the field and, in addition, two stocks of the Eastern oyster, C. virginica. No mortality was observed in control oysters. One C. virginica stock suffered ~10% mortality when challenged with both μVars tested. Two Pacific oyster stocks suffered 75 to 90% mortality, while one C. gigas stock had relatively low mortality when challenged with the AUS μVar (~22%) and higher mortality when challenged with the French μVar (~72%). Conversely, C. sikamea suffered lower mortality when challenged with the French μVar (~22%) and higher mortality with the AUS μVar (~44%). All dead oysters had higher viral loads (~1000×) as measured by quantitative PCR relative to those that survived. However, some survivors had high levels of virus, including those from species with lower mortality. Field mortality in TB correlated with laboratory mortality of the FRA μVar (69% correlation) but not with that of the AUS μVar, which also lacked correlation with the FRA μVar. The variation in response to OsHV-1 variant challenges by oyster species and stocks demonstrates the need for empirical assessment of multiple OsHV-1 variants.
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Affiliation(s)
- Carolyn S Friedman
- School of Aquatic & Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98105, USA
| | - Kimberly S Reece
- Virginia Institute of Marine Sciences, William & Mary, P.O. Box 1346, Gloucester Point, Virginia 23062, USA
| | - Bryanda J T Wippel
- School of Aquatic & Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98105, USA
| | - M Victoria Agnew
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, 701 E Pratt Street, Baltimore, MD 21202, USA
| | - Lionel Dégremont
- Ifremer, SG2M-LGPMM, Station La Tremblade, 17390 La Tremblade, France
| | - Arun K Dhar
- Aquaculture Pathology Laboratory, Animal and Comparative Biomedical Sciences, The University of Arizona, 1117 E Lowell Road, Tucson, AZ 85721, USA
| | - Peter Kirkland
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW 2568, Australia
| | - Alanna MacIntyre
- Virginia Institute of Marine Sciences, William & Mary, P.O. Box 1346, Gloucester Point, Virginia 23062, USA
| | - Benjamin Morga
- Ifremer, SG2M-LGPMM, Station La Tremblade, 17390 La Tremblade, France
| | - Clara Robison
- Virginia Institute of Marine Sciences, William & Mary, P.O. Box 1346, Gloucester Point, Virginia 23062, USA
| | - Colleen A Burge
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, 701 E Pratt Street, Baltimore, MD 21202, USA.
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12
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Mandas D, Salati F, Polinas M, Sanna MA, Zobba R, Burrai GP, Alberti A, Antuofermo E. Histopathological and Molecular Study of Pacific Oyster Tissues Provides Insights into V. aestuarianus Infection Related to Oyster Mortality. Pathogens 2020; 9:pathogens9060492. [PMID: 32575736 PMCID: PMC7350300 DOI: 10.3390/pathogens9060492] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/15/2020] [Accepted: 06/18/2020] [Indexed: 12/12/2022] Open
Abstract
Consumer preference for healthy and sustainable food products has been steadily increasing in recent years. Bivalve mollusks satisfy these characteristics and have captured ever-increasing market shares. However, the expansion of molluscan culture in worldwide and global trade have favored the spread of pathogens around the world. Combined with environmental changes and intensive production systems this has contributed to the occurrence of mass mortality episodes, thus posing a threat to the production of different species, including the Pacific oyster Crassotrea gigas. In the San Teodoro lagoon, one of the most devoted lagoons to extensive Pacific oyster aquaculture in Sardinia, a mortality outbreak was observed with an estimated 80% final loss of animal production. A study combining cultural, biomolecular and histopathological methods was conducted: (1) to investigate the presence of different Vibrio species and OsHV-1 in selected oyster tissues (digestive gland, gills, and mantle); (2) to quantify Vibrio aestuarianus and to evaluate the severity of hemocyte infiltration in infected tissues; (3) to produce post-amplification data and evaluating ToxR gene as a target for phylogenetic analyses. Results provide new insights into V. aestuarianus infection related to oyster mortality outbreaks and pave the way to the development of tools for oyster management.
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Affiliation(s)
- Daniela Mandas
- Fish Diseases and Aquaculture Center, IZS of Oristano, 09170 Oristano, Italy; (D.M.); (F.S.)
| | - Fulvio Salati
- Fish Diseases and Aquaculture Center, IZS of Oristano, 09170 Oristano, Italy; (D.M.); (F.S.)
| | - Marta Polinas
- Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy; (M.P.); (M.A.S.); (R.Z.); (G.P.B.)
| | - Marina Antonella Sanna
- Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy; (M.P.); (M.A.S.); (R.Z.); (G.P.B.)
| | - Rosanna Zobba
- Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy; (M.P.); (M.A.S.); (R.Z.); (G.P.B.)
- Mediterranean Center for Disease Control (MCDC), University of Sassari, 07100 Sassari, Italy
| | - Giovanni Pietro Burrai
- Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy; (M.P.); (M.A.S.); (R.Z.); (G.P.B.)
- Mediterranean Center for Disease Control (MCDC), University of Sassari, 07100 Sassari, Italy
| | - Alberto Alberti
- Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy; (M.P.); (M.A.S.); (R.Z.); (G.P.B.)
- Mediterranean Center for Disease Control (MCDC), University of Sassari, 07100 Sassari, Italy
- Correspondence: (A.A.); (E.A.); Tel.: +39-3209225647 (A.A.); +39-3398325369 (E.A.)
| | - Elisabetta Antuofermo
- Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy; (M.P.); (M.A.S.); (R.Z.); (G.P.B.)
- Mediterranean Center for Disease Control (MCDC), University of Sassari, 07100 Sassari, Italy
- Correspondence: (A.A.); (E.A.); Tel.: +39-3209225647 (A.A.); +39-3398325369 (E.A.)
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13
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Xin L, Huang B, Zhang H, Li C, Bai C, Wang C. OsHV-1 infection leads to mollusc tissue lesion and iron redistribution, revealing a strategy of iron limitation against pathogen. Metallomics 2020; 11:822-832. [PMID: 30843573 DOI: 10.1039/c9mt00018f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The mass mortality of molluscs caused by OsHV-1 infection has frequently occurred worldwide in recent years. Meanwhile the interaction between OsHV-1 and its host is largely unknown. Innate immunity mainly makes up the mollusc defense system, due to the lack of adaptive immunity in invertebrates. The iron limitation strategy is an indispensable facet of innate immunity across vertebrate and invertebrate species. In this study, an iron limitation strategy was interestingly found to contribute to mollusc innate immune responses against OsHV-1 infection. Firstly, ark clams, Scapharca broughtonii, were experimentally infected with OsHV-1, and serious hyperaemia in hepatopancreases and the erosion of gills were observed post OsHV-1 infection according to a histology assay. Meanwhile, based on quantification and Prussian blue staining, the process of iron efflux from ark clams was described post OsHV-1 infection. Secondly, ferritin, as an important iron storage protein, was characterized in ark clams and showed significant iron binding activity. According to the results of an immunohistochemistry assay, ferritin was supposed to be responsible for the iron translocation in ark clams post OsHV-1 infection. Its expression level was significantly fluctuant in response to OsHV-1 infection. Finally, oxidative stress was assessed by the analyses of H2O2 content, total antioxidant capacity and MDA level post OsHV-1 infection. Supplementary iron was found to promote ROS generation and death of hemocytes in vivo. These results highlighted that microenvironment changes in the essential nutrient iron should be an important aspect of the pathogenesis of OsHV-1 disease.
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Affiliation(s)
- Lusheng Xin
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, P. R. China.
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14
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Martínez-García MF, Grijalva-Chon JM, Castro-Longoria R, Re-Vega ED, Varela-Romero A, Chávez-Villalba JE. Prevalence and genotypic diversity of ostreid herpesvirus type 1 in Crassostrea gigas cultured in the Gulf of California, Mexico. DISEASES OF AQUATIC ORGANISMS 2020; 138:185-194. [PMID: 32213666 DOI: 10.3354/dao03462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In bivalve mollusk aquaculture, massive disease outbreaks with high mortality and large economic losses can occur, as in northwest Mexico in the 1990s. A range of pathogens can affect bivalves; one of great concern is ostreid herpesvirus 1 (OsHV-1), of which there are several strains. This virus has been detected in the Gulf of California in occasional or sporadic samplings, but to date, there have been few systematic studies. Monthly samples of Crassostrea gigas, water, and sediment were taken in the La Cruz coastal lagoon and analyzed by PCR. The native mollusk, Dosinia ponderosa, which lives outside the lagoon, was sampled as a control. The virus was found throughout the year only in C. gigas, with prevalence up to 60%. In total, 9 genotype variants were detected, and genetic analysis suggests that linear genotypic evolution has occurred from strain JF894308, present in La Cruz in 2011. There has been no evidence of the entry of new viral genotypes in the recent past, thus confinement of the virus within the lagoons of the Gulf of California could promote a native genotypic diversity in the short term.
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15
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Ruiz-Ramos DV, Schiebelhut LM, Hoff KJ, Wares JP, Dawson MN. An initial comparative genomic autopsy of wasting disease in sea stars. Mol Ecol 2020; 29:1087-1102. [PMID: 32069379 DOI: 10.1111/mec.15386] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 01/28/2020] [Accepted: 02/05/2020] [Indexed: 12/18/2022]
Abstract
Beginning in 2013, sea stars throughout the Eastern North Pacific were decimated by wasting disease, also known as "asteroid idiopathic wasting syndrome" (AIWS) due to its elusive aetiology. The geographic extent and taxonomic scale of AIWS meant events leading up to the outbreak were heterogeneous, multifaceted, and oftentimes unobserved; progression from morbidity to death was rapid, leaving few tell-tale symptoms. Here, we take a forensic genomic approach to discover candidate genes that may help explain sea star wasting syndrome. We report the first genome and annotation for Pisaster ochraceus, along with differential gene expression (DGE) analyses in four size classes, three tissue types, and in symptomatic and asymptomatic individuals. We integrate nucleotide polymorphisms associated with survivors of the wasting disease outbreak, DGE associated with temperature treatments in P. ochraceus, and DGE associated with wasting in another asteroid Pycnopodia helianthoides. In P. ochraceus, we found DGE across all tissues, among size classes, and between asymptomatic and symptomatic individuals; the strongest wasting-associated DGE signal was in pyloric caecum. We also found previously identified outlier loci co-occur with differentially expressed genes. In cross-species comparisons of symptomatic and asymptomatic individuals, consistent responses distinguish genes associated with invertebrate innate immunity and chemical defence, consistent with context-dependent stress responses, defensive apoptosis, and tissue degradation. Our analyses thus highlight genomic constituents that may link suspected environmental drivers (elevated temperature) with intrinsic differences among individuals (age/size, alleles associated with susceptibility) that elicit organismal responses (e.g., coelomocyte proliferation) and manifest as sea star wasting mass mortality.
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Affiliation(s)
- Dannise V Ruiz-Ramos
- Department of Life and Environmental Sciences, University of California, Merced, CA, USA
| | - Lauren M Schiebelhut
- Department of Life and Environmental Sciences, University of California, Merced, CA, USA
| | - Katharina J Hoff
- Institute for Computer Science and Mathematics, University of Greifswald, Greifswald, Germany.,Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - John P Wares
- Department of Genetics and the Odum School of Ecology, University of Georgia, Athens, GA, USA
| | - Michael N Dawson
- Department of Life and Environmental Sciences, University of California, Merced, CA, USA
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16
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Divilov K, Schoolfield B, Morga B, Dégremont L, Burge CA, Mancilla Cortez D, Friedman CS, Fleener GB, Dumbauld BR, Langdon C. First evaluation of resistance to both a California OsHV-1 variant and a French OsHV-1 microvariant in Pacific oysters. BMC Genet 2019; 20:96. [PMID: 31830898 PMCID: PMC6909534 DOI: 10.1186/s12863-019-0791-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 11/21/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Variants of the Ostreid herpesvirus 1 (OsHV-1) cause high losses of Pacific oysters globally, including in Tomales Bay, California, USA. A suite of new variants, the OsHV-1 microvariants (μvars), cause very high mortalities of Pacific oysters in major oyster-growing regions outside of the United States. There are currently no known Pacific oysters in the United States that are resistant to OsHV-1 as resistance has yet to be evaluated in these oysters. As part of an effort to begin genetic selection for resistance to OsHV-1, 71 families from the Molluscan Broodstock Program, a US West Coast Pacific oyster breeding program, were screened for survival after exposure to OsHV-1 in Tomales Bay. They were also tested in a quarantine laboratory in France where they were exposed to a French OsHV-1 microvariant using a plate assay, with survival recorded from three to seven days post-infection. RESULTS Significant heritability for survival were found for all time points in the plate assay and in the survival phenotype from a single mortality count in Tomales Bay. Genetic correlations between survival against the French OsHV-1 μvar in the plate assay and the Tomales Bay variant in the field trait were weak or non-significant. CONCLUSIONS Future breeding efforts will seek to validate the potential of genetic improvement for survival to OsHV-1 through selection using the Molluscan Broodstock Program oysters. The lack of a strong correlation in survival between OsHV-1 variants under this study's exposure conditions may require independent selection pressure for survival to each variant in order to make simultaneous genetic gains in resistance.
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Affiliation(s)
- Konstantin Divilov
- Department of Fisheries and Wildlife, Coastal Oregon Marine Experiment Station, Oregon State University, Hatfield Marine Science Center, Newport, Oregon USA
| | - Blaine Schoolfield
- Department of Fisheries and Wildlife, Coastal Oregon Marine Experiment Station, Oregon State University, Hatfield Marine Science Center, Newport, Oregon USA
| | - Benjamin Morga
- Laboratoire de Génétique et Pathologie des Mollusques Marins, Ifremer, La Tremblade, France
| | - Lionel Dégremont
- Laboratoire de Génétique et Pathologie des Mollusques Marins, Ifremer, La Tremblade, France
| | - Colleen A. Burge
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, Maryland USA
| | | | - Carolyn S. Friedman
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, USA
| | | | - Brett R. Dumbauld
- United States Department of Agriculture-Agricultural Research Service, Hatfield Marine Science Center, Newport, Oregon USA
| | - Chris Langdon
- Department of Fisheries and Wildlife, Coastal Oregon Marine Experiment Station, Oregon State University, Hatfield Marine Science Center, Newport, Oregon USA
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17
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Xin L, Wei Z, Bai C, Chen H, Huang B, Wang C. Influence of temperature on the pathogenicity of Ostreid herpesvirus-1 in ark clam, Scapharca broughtonii. J Invertebr Pathol 2019; 169:107299. [PMID: 31786248 DOI: 10.1016/j.jip.2019.107299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 11/22/2019] [Accepted: 11/26/2019] [Indexed: 11/27/2022]
Abstract
OsHV-1 is an epidemic pathogen of molluscs, and temperature has been recognized as a decisive environmental factor in its pathogenicity. In recent years, ark clam, Scapharca broughtonii, emerged as a host for OsHV-1. In the north of China, massive summer mortalities of ark clams infected with OsHV-1 have been continuously reported since 2012. However, the interaction between temperature and the pathogenicity of OsHV-1 was unknown in ark clams. In this study, the effect of temperature (10 °C to 18 °C stepped by 2 °C) on the occurrence of OsHV-1 disease in ark clams was analyzed. OsHV-1 infection led to gill erosion but not below the critical low temperature (between 12 °C and 14 °C). However, OsHV-1 persisted for more than 2 weeks at 12 °C post inoculation and replication was reactivated when the temperature was elevated to 18 °C. No significant reduction of OsHV-1 DNA load was found when the temperature descended to 12 °C from 18 °C, while the gill erosion remained unchanged. Ark clams failed to show the capability of effective clearance of OsHV-1 below the critical low temperature. Our results demonstrated that the pathogenicity of OsHV-1 was influenced significantly by temperature. Moreover, high temperature favored infection, which could provide more information to understand summer mortality of ark clams.
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Affiliation(s)
- Lusheng Xin
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Zhixin Wei
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Changming Bai
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Hao Chen
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China
| | - Bowen Huang
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Chongming Wang
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China.
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18
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Martenot C, Faury N, Morga B, Degremont L, Lamy JB, Houssin M, Renault T. Exploring First Interactions Between Ostreid Herpesvirus 1 (OsHV-1) and Its Host, Crassostrea gigas: Effects of Specific Antiviral Antibodies and Dextran Sulfate. Front Microbiol 2019; 10:1128. [PMID: 31178841 PMCID: PMC6543491 DOI: 10.3389/fmicb.2019.01128] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/03/2019] [Indexed: 12/18/2022] Open
Abstract
Viral entry mechanisms of herpesviruses constitute a highly complex process which implicates several viral glycoproteins and different receptors on the host cell surfaces. This initial infection stage was currently undescribed for Ostreid herpes virus 1 (OsHV-1), a herpesvirus infecting bivalves including the Pacific oyster, Crassostrea gigas. To identify OsHV-1 glyproteins implicated in the attachment of the virus to oyster cells, three viral putative membrane proteins, encoded by ORF 25, 41, and 72, were selected and polyclonal antibodies against these targets were used to explore first interactions between the virus and host cells. In addition, effects of dextran sulfate, a negative charged sulfated polysaccharide, were investigated on OsHV-1 infection. Effects of antiviral antibodies and dextran sulfate were evaluated by combining viral DNA and RNA detection in spat (in vivo trials) and in oyster hemolymph (in vitro trials). Results showed that viral protein encoded by ORF 25 appeared to be involved in interaction between OsHV-1 and host cells even if other proteins are likely implicated, such as proteins encoded by ORF 72 and ORF 41. Dextran sulfate at 30 μg/mL significantly reduced the spat mortality rate in the experimental conditions. Taken together, these results contribute to better understanding the pathogenesis of the viral infection, especially during the first stage of OsHV-1 infection, and open the way toward new approaches to control OsHV-1 infection in confined facilities.
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Affiliation(s)
- Claire Martenot
- Institut Français de Recherche pour l'Exploitation de la Mer, Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | - Nicole Faury
- Institut Français de Recherche pour l'Exploitation de la Mer, Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | - Benjamin Morga
- Institut Français de Recherche pour l'Exploitation de la Mer, Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | - Lionel Degremont
- Institut Français de Recherche pour l'Exploitation de la Mer, Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | - Jean-Baptiste Lamy
- Institut Français de Recherche pour l'Exploitation de la Mer, Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | | | - Tristan Renault
- Département Ressources Biologiques et Environnement, Institut Français de Recherche pour l'Exploitation de la Mer, Nantes, France
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19
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King WL, Siboni N, Williams NLR, Kahlke T, Nguyen KV, Jenkins C, Dove M, O'Connor W, Seymour JR, Labbate M. Variability in the Composition of Pacific Oyster Microbiomes Across Oyster Families Exhibiting Different Levels of Susceptibility to OsHV-1 μvar Disease. Front Microbiol 2019; 10:473. [PMID: 30915058 PMCID: PMC6421512 DOI: 10.3389/fmicb.2019.00473] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/22/2019] [Indexed: 11/13/2022] Open
Abstract
Oyster diseases are a major impediment to the profitability and growth of the oyster aquaculture industry. In recent years, geographically widespread outbreaks of disease caused by ostreid herpesvirus-1 microvariant (OsHV-1 μvar) have led to mass mortalities among Crassostrea gigas, the Pacific Oyster. Attempts to minimize the impact of this disease have been largely focused on breeding programs, and although these have shown some success in producing oyster families with reduced mortality, the mechanism(s) behind this protection is poorly understood. One possible factor is modification of the C. gigas microbiome. To explore how breeding for resistance to OsHV-1 μvar affects the oyster microbiome, we used 16S rRNA amplicon sequencing to characterize the bacterial communities associated with 35 C. gigas families, incorporating oysters with different levels of susceptibility to OsHV-1 μvar disease. The microbiomes of disease-susceptible families were significantly different to the microbiomes of disease-resistant families. OTUs assigned to the Photobacterium, Vibrio, Aliivibrio, Streptococcus, and Roseovarius genera were associated with low disease resistance. In partial support of this finding, qPCR identified a statistically significant increase of Vibrio-specific 16S rRNA gene copies in the low disease resistance families, possibly indicative of a reduced host immune response to these pathogens. In addition to these results, examination of the core microbiome revealed that each family possessed a small core community, with OTUs assigned to the Winogradskyella genus and the Bradyrhizobiaceae family consistent members across most disease-resistant families. This study examines patterns in the microbiome of oyster families exhibiting differing levels of OsHV-1 μvar disease resistance and reveals some key bacterial taxa that may provide a protective or detrimental role in OsHV-1 μvar disease outbreaks.
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Affiliation(s)
- William L King
- The School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia.,Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Nachshon Siboni
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Nathan L R Williams
- The School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia
| | - Tim Kahlke
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Khue Viet Nguyen
- The School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia.,Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Cheryl Jenkins
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, NSW, Australia
| | - Michael Dove
- NSW Department of Primary Industries, Port Stephens Fisheries Institute, Port Stephens, NSW, Australia
| | - Wayne O'Connor
- NSW Department of Primary Industries, Port Stephens Fisheries Institute, Port Stephens, NSW, Australia
| | - Justin R Seymour
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Maurizio Labbate
- The School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia
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20
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Lafont M, Goncalves P, Guo X, Montagnani C, Raftos D, Green T. Transgenerational plasticity and antiviral immunity in the Pacific oyster (Crassostrea gigas) against Ostreid herpesvirus 1 (OsHV-1). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 91:17-25. [PMID: 30278186 DOI: 10.1016/j.dci.2018.09.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/03/2018] [Accepted: 09/26/2018] [Indexed: 06/08/2023]
Abstract
The oyster's immune system is capable of adapting upon exposure to a pathogen-associated molecular pattern (PAMP) to have an enhanced secondary response against the same type of pathogen. This has been demonstrated using poly(I:C) to elicit an antiviral response in the Pacific oyster (Crassostrea gigas) against Ostreid herpesvirus (OsHV-1). Improved survival following exposure to poly(I:C) has been found in later life stages (within-generational immune priming) and in the next generation (transgenerational immune priming). The mechanism that the oyster uses to transfer immunity to the next generation is unknown. Here we show that oyster larvae have higher survival to OsHV-1 when their mothers, but not their fathers, are exposed to poly(I:C) prior to spawning. RNA-seq provided no evidence to suggest that parental exposure to poly(I:C) reconfigures antiviral gene expression in unchallenged larvae. We conclude that the improved survival of larvae might occur via maternal provisioning of antiviral compounds in the eggs.
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Affiliation(s)
- Maxime Lafont
- Sydney Institute of Marine Science, Chowder Bay, Sydney, Australia; IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, France
| | - Priscila Goncalves
- Sydney Institute of Marine Science, Chowder Bay, Sydney, Australia; Macquarie University, Department of Biological Sciences, Sydney, Australia
| | - Ximing Guo
- Haskin Shellfish Research Laboratory, Rutgers University, Port Norris, NJ, USA
| | - Caroline Montagnani
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, France
| | - David Raftos
- Sydney Institute of Marine Science, Chowder Bay, Sydney, Australia; Macquarie University, Department of Biological Sciences, Sydney, Australia
| | - Timothy Green
- Sydney Institute of Marine Science, Chowder Bay, Sydney, Australia; Macquarie University, Department of Biological Sciences, Sydney, Australia.
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21
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King WL, Jenkins C, Seymour JR, Labbate M. Oyster disease in a changing environment: Decrypting the link between pathogen, microbiome and environment. MARINE ENVIRONMENTAL RESEARCH 2019; 143:124-140. [PMID: 30482397 DOI: 10.1016/j.marenvres.2018.11.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/20/2018] [Accepted: 11/15/2018] [Indexed: 06/09/2023]
Abstract
Shifting environmental conditions are known to be important triggers of oyster diseases. The mechanism(s) behind these synergistic effects (interplay between host, environment and pathogen/s) are often not clear, although there is evidence that shifts in environmental conditions can affect oyster immunity, and pathogen growth and virulence. However, the impact of shifting environmental parameters on the oyster microbiome and how this affects oyster health and susceptibility to infectious pathogens remains understudied. In this review, we summarise the major diseases afflicting oysters with a focus on the role of environmental factors that can catalyse or amplify disease outbreaks. We also consider the potential role of the oyster microbiome in buffering or augmenting oyster disease outbreaks and suggest that a deeper understanding of the oyster microbiome, its links to the environment and its effect on oyster health and disease susceptibility, is required to develop new frameworks for the prevention and management of oyster diseases.
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Affiliation(s)
- William L King
- The School of Life Sciences, University of Technology Sydney, NSW, Australia; Climate Change Cluster, University of Technology Sydney, NSW, Australia
| | - Cheryl Jenkins
- Elizabeth Macarthur Institute, New South Wales Department of Primary Industries, Menangle, NSW, Australia
| | - Justin R Seymour
- Climate Change Cluster, University of Technology Sydney, NSW, Australia
| | - Maurizio Labbate
- The School of Life Sciences, University of Technology Sydney, NSW, Australia.
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22
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Toldrà A, Andree KB, Bertomeu E, Roque A, Carrasco N, Gairín I, Furones MD, Campàs M. Rapid capture and detection of ostreid herpesvirus-1 from Pacific oyster Crassostrea gigas and seawater using magnetic beads. PLoS One 2018; 13:e0205207. [PMID: 30281676 PMCID: PMC6169968 DOI: 10.1371/journal.pone.0205207] [Citation(s) in RCA: 10] [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: 07/02/2018] [Accepted: 09/20/2018] [Indexed: 12/20/2022] Open
Abstract
Ostreid herpesvirus-1 (OsHV-1) has been involved in mass mortality episodes of Pacific oysters Crassostrea gigas throughout the world, causing important economic losses to the aquaculture industry. In the present study, magnetic beads (MBs) coated with an anionic polymer were used to capture viable OsHV-1 from two types of naturally infected matrix: oyster homogenate and seawater. Adsorption of the virus on the MBs and characterisation of the MB-virus conjugates was demonstrated by real-time quantitative PCR (qPCR). To study the infective capacity of the captured virus, MB-virus conjugates were injected in the adductor muscle of naïve spat oysters, using oyster homogenate and seawater without MBs as positive controls, and bare MBs and sterile water as negative controls. Mortalities were induced after injection with MB-virus conjugates and in positive controls, whereas no mortalities were recorded in negative controls. Subsequent OsHV-1 DNA and RNA analysis of the oysters by qPCR and reverse transcription qPCR (RT-qPCR), respectively, confirmed that the virus was the responsible for the mortality event and the ability of the MBs to capture viable viral particles. The capture of viable OsHV-1 using MBs is a rapid and easy isolation method and a promising tool, combined with qPCR, to be applied to OsHV-1 detection in aquaculture facilities.
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Affiliation(s)
- Anna Toldrà
- IRTA, Ctra., Sant Carles de la Ràpita, Tarragona, Spain
| | | | | | - Ana Roque
- IRTA, Ctra., Sant Carles de la Ràpita, Tarragona, Spain
| | | | - Ignasi Gairín
- IRTA, Ctra., Sant Carles de la Ràpita, Tarragona, Spain
| | | | - Mònica Campàs
- IRTA, Ctra., Sant Carles de la Ràpita, Tarragona, Spain
- * E-mail:
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23
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Abbadi M, Zamperin G, Gastaldelli M, Pascoli F, Rosani U, Milani A, Schivo A, Rossetti E, Turolla E, Gennari L, Toffan A, Arcangeli G, Venier P. Identification of a newly described OsHV-1 µvar from the North Adriatic Sea (Italy). J Gen Virol 2018; 99:693-703. [PMID: 29580370 PMCID: PMC5994699 DOI: 10.1099/jgv.0.001042] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The surveillance activities for abnormal bivalve mortality events in Italy include the diagnosis of ostreid herpesvirus type 1 (OsHV-1) in symptomatic oysters. OsHV-1-positive oysters (Crassostrea gigas) were used as a source for in vivo virus propagation and a virus-rich sample was selected to perform shotgun sequencing based on Illumina technology. Starting from this unpurified supernatant sample from gills and mantle, we generated 3.5 million reads (2×300 bp) and de novo assembled the whole genome of an Italian OsHV-1 microvariant (OsHV-1-PT). The OsHV-1-PT genome encodes 125 putative ORFs, 7 of which had not previously been predicted in other sequenced Malacoherpesviridae. Overall, OsHV-1-PT displays typical microvariant OsHV-1 genome features, while few polymorphisms (0.08 %) determine its uniqueness. As little is known about the genetic determinants of OsHV-1 virulence, comparing complete OsHV-1 genomes supports a better understanding of the virus pathogenicity and provides new insights into virus-host interactions.
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Affiliation(s)
- Miriam Abbadi
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy.,Department of Biology, University of Padova, Padova (PD), Italy
| | - Gianpiero Zamperin
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | | | - Francesco Pascoli
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | - Umberto Rosani
- Department of Biology, University of Padova, Padova (PD), Italy
| | - Adelaide Milani
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | - Alessia Schivo
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | - Emanuele Rossetti
- Consorzio Cooperative Pescatori del Polesine, Scardovari (RO), Italy
| | | | | | - Anna Toffan
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | - Giuseppe Arcangeli
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | - Paola Venier
- Department of Biology, University of Padova, Padova (PD), Italy
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24
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Green TJ, Speck P. Antiviral Defense and Innate Immune Memory in the Oyster. Viruses 2018; 10:v10030133. [PMID: 29547519 PMCID: PMC5869526 DOI: 10.3390/v10030133] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/06/2018] [Accepted: 03/14/2018] [Indexed: 12/17/2022] Open
Abstract
The Pacific oyster, Crassostrea gigas, is becoming a valuable model for investigating antiviral defense in the Lophotrochozoa superphylum. In the past five years, improvements to laboratory-based experimental infection protocols using Ostreid herpesvirus I (OsHV-1) from naturally infected C. gigas combined with next-generation sequencing techniques has revealed that oysters have a complex antiviral response involving the activation of all major innate immune pathways. Experimental evidence indicates C. gigas utilizes an interferon-like response to limit OsHV-1 replication and spread. Oysters injected with a viral mimic (polyI:C) develop resistance to OsHV-1. Improved survival following polyI:C injection was found later in life (within-generational immune priming) and in the next generation (multi-generational immune priming). These studies indicate that the oyster's antiviral defense system exhibits a form of innate immune-memory. An important priority is to identify the molecular mechanisms responsible for this phenomenon. This knowledge will motivate the development of practical and cost-effective treatments for improving oyster health in aquaculture.
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Affiliation(s)
- Timothy J Green
- Centre for Shellfish Research & Department of Fisheries and Aquaculture, Vancouver Island University, Nanaimo, BC V9R 5S5, Canada.
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
| | - Peter Speck
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia.
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25
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Cáceres-Martínez J, Vásquez-Yeomans R, Danigo P, Reyes-Roel C. Histological Alterations in Pacific Oysters Crassostrea gigas that Survived a Summer Mortality Event in Baja California, Mexico. JOURNAL OF AQUATIC ANIMAL HEALTH 2018; 30:31-38. [PMID: 29595887 DOI: 10.1002/aah.10006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 10/23/2017] [Indexed: 06/08/2023]
Abstract
A mortality episode (>90%) of triploid and diploid Pacific oysters Crassostrea gigas cultured in Baja California Sur occurred during summer 2012, coinciding with a thermal anomaly, an algal bloom, and low oxygen values. To help explain the cause of the mortalities, histological analyses and molecular tests for specific pathogens (ostreid herpesvirus 1 [OsHV-1] and Perkinsus marinus) were performed on oysters surviving at the end of the episode. Triploid oysters showed a high percentage of males (43%) and hermaphrodites (30%); 93% of these oysters were in the gonadic reabsorption stage, and in some cases, hemocytes completely filled the lumen of the gonadic follicles. Oysters presented large areas with severe hemocyte infiltration that extended toward the digestive gland. Diploid oysters showed similar gonad alterations. None of samples showed histological or molecular evidence of OsHV-1 or P. marinus. Histological alterations can be related to physiological disorders caused by the mechanism driving summer mortality. This is the first case history of a summer mortality episode among Pacific oysters in Mexico.
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Affiliation(s)
- Jorge Cáceres-Martínez
- Centro de Investigación Científica y de Educación Superior de Ensenada, Carretera Ensenada-Tijuana Number 3918, Zona Playitas, 22860, Ensenada, Baja California, México
| | - Rebeca Vásquez-Yeomans
- Instituto de Sanidad Acuícola, Asociación Civil, Calle de la Marina Sin Número, esquina Caracoles, Fraccionamiento Playa Ensenada, 22880, Ensenada, Baja California, México
| | - Philippe Danigo
- Sol Azul, Sociedad Anónima de Capital Variable, Boulevard Álvaro Obregón 720-2, Colonia El Esterito, 23020, La Paz, Baja California Sur, México
| | - Carlos Reyes-Roel
- Sol Azul, Sociedad Anónima de Capital Variable, Boulevard Álvaro Obregón 720-2, Colonia El Esterito, 23020, La Paz, Baja California Sur, México
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26
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Deines P, Lachnit T, Bosch TCG. Competing forces maintain theHydrametaorganism. Immunol Rev 2017; 279:123-136. [DOI: 10.1111/imr.12564] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Peter Deines
- Zoological Institute; Christian Albrechts University Kiel; Kiel Germany
| | - Tim Lachnit
- Zoological Institute; Christian Albrechts University Kiel; Kiel Germany
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27
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Young T, Kesarcodi-Watson A, Alfaro AC, Merien F, Nguyen TV, Mae H, Le DV, Villas-Bôas S. Differential expression of novel metabolic and immunological biomarkers in oysters challenged with a virulent strain of OsHV-1. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 73:229-245. [PMID: 28373065 DOI: 10.1016/j.dci.2017.03.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 03/30/2017] [Accepted: 03/30/2017] [Indexed: 06/07/2023]
Abstract
Early lifestages of the Pacific oyster (Crassostrea gigas) are highly susceptible to infection by OsHV-1 μVar, but little information exists regarding metabolic or pathophysiological responses of larval hosts. Using a metabolomics approach, we identified a range of metabolic and immunological responses in oyster larvae exposed to OsHV-1 μVar; some of which have not previously been reported in molluscs. Multivariate analyses of entire metabolite profiles were able to separate infected from non-infected larvae. Correlation analysis revealed the presence of major perturbations in the underlying biochemical networks and secondary pathway analysis of functionally-related metabolites identified a number of prospective pathways differentially regulated in virus-exposed larvae. These results provide new insights into the pathogenic mechanisms of OsHV-1 infection in oyster larvae, which may be applied to develop disease mitigation strategies and/or as new phenotypic information for selective breeding programmes aiming to enhance viral resistance.
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Affiliation(s)
- Tim Young
- Institute for Applied Ecology New Zealand, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand; Metabolomics Laboratory, School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand
| | | | - Andrea C Alfaro
- Institute for Applied Ecology New Zealand, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand.
| | - Fabrice Merien
- AUT-Roche Diagnostics Laboratory, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand
| | - Thao V Nguyen
- Institute for Applied Ecology New Zealand, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand
| | - Hannah Mae
- Cawthron Institute, 98 Halifax Street East, Private Bag 2, Nelson 7042, New Zealand
| | - Dung V Le
- Institute for Applied Ecology New Zealand, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand
| | - Silas Villas-Bôas
- Metabolomics Laboratory, School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand
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28
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Complete genome sequence of Ostreid herpesvirus type 1 µVar isolated during mortality events in the Pacific oyster Crassostrea gigas in France and Ireland. Virology 2017; 509:239-251. [PMID: 28672223 DOI: 10.1016/j.virol.2017.06.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 06/14/2017] [Accepted: 06/23/2017] [Indexed: 12/13/2022]
Abstract
Infections with Ostreid herpesvirus 1 (OsHV-1) microvariants in young Pacific oysters are associated with massive mortality events and significant economic losses. Previous studies, focusing on few regions of the genome, have revealed the genomic diversity of these genotypes with respect to the reference type. We used a NGS process to sequence the whole genome of the OsHV-1 µVar in infected individuals, collected during mortality events in France and Ireland. The final genome length of OsHV-1 µVar was approximately 205kbp, shorter than the reference genotype and the overall genome organisation resembled herpes simplex viruses. 94.4% similarity was observed with the OsHV-1 reference genotype. Large indels, including five deletions and three insertions were found to induce the loss and the addition of several ORFs, summed with codon substitutions in 64% of genes shared with the reference type. This diversity raises the question of the exact origin and evolution of OsHV-1 µVar.
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29
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Martenot C, Gervais O, Chollet B, Houssin M, Renault T. Haemocytes collected from experimentally infected Pacific oysters, Crassostrea gigas: Detection of ostreid herpesvirus 1 DNA, RNA, and proteins in relation with inhibition of apoptosis. PLoS One 2017; 12:e0177448. [PMID: 28542284 PMCID: PMC5436676 DOI: 10.1371/journal.pone.0177448] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 04/27/2017] [Indexed: 11/18/2022] Open
Abstract
Recent transcriptomic approaches focused on anti-viral immunity in molluscs lead to the assumption that the innate immune system, such as apoptosis, plays a crucial role against ostreid herpesvirus type 1 (OsHV-1), infecting Pacific cupped oyster, Crassostrea gigas. Apoptosis constitutes a major mechanism of anti-viral response by limiting viral spread and eliminating infected cells. In this way, an OsHV-1 challenge was performed and oysters were monitored at three times post injection to investigate viral infection and host response: 2h (early after viral injection in the adductor muscle), 24h (intermediate time), and 48h (just before first oyster mortality record). Virus infection, associated with high cumulative mortality rates (74% and 100%), was demonstrated in haemocytes by combining several detection techniques such as real-time PCR, real-time RT PCR, immunofluorescence assay, and transmission electron microscopy examination. High viral DNA amounts ranged from 5.46×104 to 3.68×105 DNA copies ng-1 of total DNA, were detected in dead oysters and an increase of viral transcripts was observed from 2, 24, and 48hpi for the five targeted OsHV-1 genes encoding three putative membrane proteins (ORFs 25, 41, and 72), a putative dUTPase (ORF 75), and a putative apoptosis inhibitor (ORF 87). Apoptosis was studied at molecular and cellular levels with an early marker (phosphatidyl-serine externalisation measured by flow cytometry and epifluorescence microscopy) and a later parameter (DNA fragmentation by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling assay (TUNEL)). The down-regulation of genes encoding proteins involved in the activation of the apoptotic pathway (TNF and caspase 3) and the up-regulation of genes encoding anti-apoptotic proteins (IAP-2, and Bcl-2) suggested an important anti-apoptosis phenomenon in haemocytes from OsHV-1 infected oysters at 24 and 48hpi. Additionally, more phosphatidyl-serines were externalized and more cells with DNA fragmentation were observed in haemocytes collected from artificial seawater injected oysters than in haemocytes collected from OsHV-1 infected oysters at 24 and 48hpi, suggesting an inhibition of the apoptotic process in presence of the virus. In conclusion, this study is the first to focus on C. gigas haemocytes, cells involved in the host immune defense, during an OsHV-1 challenge in controlled conditions by combining various and original approaches to investigate apoptosis at molecular and cellular levels.
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Affiliation(s)
- Claire Martenot
- Ifremer (Institut Français de Recherche pour l'Exploitation de la Mer), Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
- * E-mail:
| | - Ophélie Gervais
- Ifremer (Institut Français de Recherche pour l'Exploitation de la Mer), Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | - Bruno Chollet
- Ifremer (Institut Français de Recherche pour l'Exploitation de la Mer), Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | | | - Tristan Renault
- Ifremer, Département Ressources Biologiques et Environnement, Nantes, France
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30
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Arzul I, Corbeil S, Morga B, Renault T. Viruses infecting marine molluscs. J Invertebr Pathol 2017; 147:118-135. [PMID: 28189502 DOI: 10.1016/j.jip.2017.01.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 01/20/2017] [Accepted: 01/23/2017] [Indexed: 11/19/2022]
Abstract
Although a wide range of viruses have been reported in marine molluscs, most of these reports rely on ultrastructural examination and few of these viruses have been fully characterized. The lack of marine mollusc cell lines restricts virus isolation capacities and subsequent characterization works. Our current knowledge is mostly restricted to viruses affecting farmed species such as oysters Crassostrea gigas, abalone Haliotis diversicolor supertexta or the scallop Chlamys farreri. Molecular approaches which are needed to identify virus affiliation have been carried out for a small number of viruses, most of them belonging to the Herpesviridae and birnaviridae families. These last years, the use of New Generation Sequencing approach has allowed increasing the number of sequenced viral genomes and has improved our capacity to investigate the diversity of viruses infecting marine molluscs. This new information has in turn allowed designing more efficient diagnostic tools. Moreover, the development of experimental infection protocols has answered some questions regarding the pathogenesis of these viruses and their interactions with their hosts. Control and management of viral diseases in molluscs mostly involve active surveillance, implementation of effective bio security measures and development of breeding programs. However factors triggering pathogen development and the life cycle and status of the viruses outside their mollusc hosts still need further investigations.
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Affiliation(s)
- Isabelle Arzul
- Ifremer, SG2M-LGPMM, Station La Tremblade, 17390 La Tremblade, France
| | - Serge Corbeil
- CSIRO Australian Animal Health Laboratory, 5 Portarlington Road, Geelong East, Victoria 3220, Australia
| | - Benjamin Morga
- Ifremer, SG2M-LGPMM, Station La Tremblade, 17390 La Tremblade, France
| | - Tristan Renault
- Ifremer, RBE, Centre Atlantique, Rue de l'Ile d'Yeu, BP 21105, 44311 Nantes Cedex 03, France.
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31
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Guo X, Ford SE. Infectious diseases of marine molluscs and host responses as revealed by genomic tools. Philos Trans R Soc Lond B Biol Sci 2016; 371:rstb.2015.0206. [PMID: 26880838 DOI: 10.1098/rstb.2015.0206] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
More and more infectious diseases affect marine molluscs. Some diseases have impacted commercial species including MSX and Dermo of the eastern oyster, QPX of hard clams, withering syndrome of abalone and ostreid herpesvirus 1 (OsHV-1) infections of many molluscs. Although the exact transmission mechanisms are not well understood, human activities and associated environmental changes often correlate with increased disease prevalence. For instance, hatcheries and large-scale aquaculture create high host densities, which, along with increasing ocean temperature, might have contributed to OsHV-1 epizootics in scallops and oysters. A key to understanding linkages between the environment and disease is to understand how the environment affects the host immune system. Although we might be tempted to downplay the role of immunity in invertebrates, recent advances in genomics have provided insights into host and parasite genomes and revealed surprisingly sophisticated innate immune systems in molluscs. All major innate immune pathways are found in molluscs with many immune receptors, regulators and effectors expanded. The expanded gene families provide great diversity and complexity in innate immune response, which may be key to mollusc's defence against diverse pathogens in the absence of adaptive immunity. Further advances in host and parasite genomics should improve our understanding of genetic variation in parasite virulence and host disease resistance.
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Affiliation(s)
- Ximing Guo
- Haskin Shellfish Research Laboratory, Department of Marine and Coastal Sciences, Rutgers University, 6959 Miller Avenue, Port Norris, NJ 08349, USA
| | - Susan E Ford
- Haskin Shellfish Research Laboratory, Department of Marine and Coastal Sciences, Rutgers University, 6959 Miller Avenue, Port Norris, NJ 08349, USA
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Bueno R, Perrott M, Dunowska M, Brosnahan C, Johnston C. In situ hybridization and histopathological observations during ostreid herpesvirus-1-associated mortalities in Pacific oysters Crassostrea gigas. DISEASES OF AQUATIC ORGANISMS 2016; 122:43-55. [PMID: 27901503 DOI: 10.3354/dao03062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In a previous longitudinal study conducted during a mortality investigation associated with ostreid herpesvirus-1 (OsHV-1) microvariant in New Zealand Pacific oysters in 2010-2011, temporality of OsHV-1 nucleic acid detection by real-time PCR assay and onset of Pacific oyster mortality was observed. The present study further elucidated the role of OsHV-1 using an in situ hybridization (ISH) assay on sections of Pacific oysters collected from the same longitudinal study. Hybridization of the labelled probe with the target region of the OsHV-1 genome in infected cells was detected colorimetrically using nitro blue tetrazolium (NBT). OsHV-1 presence and distribution in spat indicated by the ISH signal was then compared with the existence of pathological changes in oyster tissues. Dark blue to purplish black NBT cell labelling was seen predominantly in the stroma of the mantle and gills at Day 5 post introduction to the farm. The distribution and location of ISH signals indicated the extent of OsHV-1-infected cells in multiple tissues. Histopathological abnormalities were mostly non-specific; however, a progressive pattern of increasingly widespread haemocytosis coincided with the appearance of OsHV-1-infected cells in spat collected at different time-points. The visualisation of an increasing number of OsHV-1-positive cells in spat prior to a marked increase in mortality indicated the strong likelihood of an on-going and active viral infection in some oysters. Further studies are recommended to elucidate OsHV-1 pathogenesis in Pacific oysters in association with other potentially causal variables, such as elevated temperature and interaction with Vibrio spp. bacteria.
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Affiliation(s)
- Rudolfo Bueno
- Animal Health Laboratory, Investigation, Diagnostic Centres and Response-Wallaceville, Ministry for Primary Industries, 66 Ward St, PO Box 40742, Upper Hutt 5018, New Zealand
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Prado-Alvarez M, Darmody G, Hutton S, O'Reilly A, Lynch SA, Culloty SC. Occurrence of OsHV-1 in Crassostrea gigas Cultured in Ireland during an Exceptionally Warm Summer. Selection of Less Susceptible Oysters. Front Physiol 2016; 7:492. [PMID: 27877131 PMCID: PMC5099240 DOI: 10.3389/fphys.2016.00492] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 10/11/2016] [Indexed: 11/13/2022] Open
Abstract
The occurrence of OsHV-1, a herpes virus causing mass mortality in the Pacific oyster Crassostrea gigas was investigated with the aim to select individuals with different susceptibility to the infection. Naïve spat transferred to infected areas and juveniles currently being grown at those sites were analyzed using molecular and histology approaches. The survey period distinguishes itself by very warm temperatures reaching up to 3.5°C above the average. The virus was not detected in the virus free area although a spread of the disease could be expected due to high temperatures. Overall mortality, prevalence of infection and viral load was higher in spat confirming the higher susceptibility in early life stages. OsHV-1 and oyster mortality were detected in naïve spat after 15 days of cohabitation with infected animals. Although, infection was associated with mortality in spat, the high seawater temperatures could also be the direct cause of mortality at the warmest site. One stock of juveniles suffered an event of abnormal mortality that was significantly associated with OsHV-1 infection. Those animals were infected with a previously undescribed microvariant whereas the other stocks were infected with OsHV-1 μVar. Cell lesions due to the infection were observed by histology and true infections were corroborated by in situ hybridization. Survivors from the natural outbreak were exposed to OsHV-1 μVar by intramuscular injection and were compared to naïve animals. The survival rate in previously exposed animals was significantly higher than in naïve oysters. Results derived from this study allowed the selection of animals that might possess interesting characteristics for future analysis on OsHV-1 resistance.
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Affiliation(s)
- Maria Prado-Alvarez
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Grainne Darmody
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Stephen Hutton
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Amy O'Reilly
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Sharon A Lynch
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Sarah C Culloty
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
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López-Sanmartín M, López-Fernández JR, Cunha ME, De la Herrán R, Navas JI. Ostreid herpesvirus in wild oysters from the Huelva coast (SW Spain). DISEASES OF AQUATIC ORGANISMS 2016; 120:231-240. [PMID: 27503919 DOI: 10.3354/dao03031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This is the first report of ostreid herpesvirus 1 microvariant (OsHV-1 µVar) infecting natural oyster beds located in Huelva (SW Spain). The virus was detected in 3 oyster species present in the intertidal zone: Crassostrea gigas (Thunberg, 1793), C. angulata (Lamarck, 1819) and, for the first time, in Ostrea stentina Payraudeau, 1826. Oysters were identified by a specific polymerase chain reaction (PCR) and posterior restriction fragment length polymorphism (RFLP) analysis based on cytochrome oxidase I (COI) mitochondrial DNA. Results confirmed that C. angulata still remains the dominant oyster population in SW Spain despite the introduction of C. gigas for cultivation in the late 1970s, and its subsequent naturalization. C. angulata shows a higher haplotype diversity than C. gigas. OsHV-1 virus was detected by PCR with C2/C6 pair primers. Posterior RFLP analyses with the restriction enzyme MfeI were done in order to reveal the OsHV-1 µVar. Detections were confirmed by DNA sequencing, and infections were evidenced by in situ hybridization in C. gigas, C. angulata and O. stentina samples. The prevalence was similar among the 3 oyster species but varied between sampling locations, being higher in areas with greater harvesting activities. OsHV-1 µVar accounted for 93% of all OsHV-1 detected.
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Affiliation(s)
- M López-Sanmartín
- IFAPA Centro Agua del Pino, Consejería de Agricultura, Pesca y Desarrollo Rural, Junta de Andalucía, Ctra. El Rompido-Punta Umbría Km 3.8, 21459 Cartaya, Huelva, Spain
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In situ localization and tissue distribution of ostreid herpesvirus 1 proteins in infected Pacific oyster, Crassostrea gigas. J Invertebr Pathol 2016; 136:124-35. [PMID: 27066775 DOI: 10.1016/j.jip.2016.04.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 11/20/2022]
Abstract
Immunohistochemistry (IHC) assays were conducted on paraffin sections from experimentally infected spat and unchallenged spat produced in hatchery to determine the tissue distribution of three viral proteins within the Pacific oyster, Crassostrea gigas. Polyclonal antibodies were produced from recombinant proteins corresponding to two putative membrane proteins and one putative apoptosis inhibitor encoded by ORF 25, 72, and 87, respectively. Results were then compared to those obtained by in situ hybridization performed on the same individuals, and showed a substantial agreement according to Landis and Koch numeric scale. Positive signals were mainly observed in connective tissue of gills, mantle, adductor muscle, heart, digestive gland, labial palps, and gonads of infected spat. Positive signals were also reported in digestive epithelia. However, few positive signals were also observed in healthy appearing oysters (unchallenged spat) and could be due to virus persistence after a primary infection. Cellular localization of staining seemed to be linked to the function of the viral protein targeted. A nucleus staining was preferentially observed with antibodies targeting the putative apoptosis inhibitor protein whereas a cytoplasmic localization was obtained using antibodies recognizing putative membrane proteins. The detection of viral proteins was often associated with histopathological changes previously reported during OsHV-1 infection by histology and transmission electron microscopy. Within the 6h after viral suspension injection, positive signals were almost at the maximal level with the three antibodies and all studied organs appeared infected at 28h post viral injection. Connective tissue appeared to be a privileged site for OsHV-1 replication even if positive signals were observed in the epithelium cells of different organs which may be interpreted as a hypothetical portal of entry or release for the virus. IHC constitutes a suited method for analyzing the early infection stages of OsHV-1 infection and a useful tool to investigate interactions between OsHV-1 and its host at a protein level.
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Burge CA, Friedman CS, Getchell R, House M, Lafferty KD, Mydlarz LD, Prager KC, Sutherland KP, Renault T, Kiryu I, Vega-Thurber R. Complementary approaches to diagnosing marine diseases: a union of the modern and the classic. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150207. [PMID: 26880839 PMCID: PMC4760137 DOI: 10.1098/rstb.2015.0207] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2015] [Indexed: 01/01/2023] Open
Abstract
Linking marine epizootics to a specific aetiology is notoriously difficult. Recent diagnostic successes show that marine disease diagnosis requires both modern, cutting-edge technology (e.g. metagenomics, quantitative real-time PCR) and more classic methods (e.g. transect surveys, histopathology and cell culture). Here, we discuss how this combination of traditional and modern approaches is necessary for rapid and accurate identification of marine diseases, and emphasize how sole reliance on any one technology or technique may lead disease investigations astray. We present diagnostic approaches at different scales, from the macro (environment, community, population and organismal scales) to the micro (tissue, organ, cell and genomic scales). We use disease case studies from a broad range of taxa to illustrate diagnostic successes from combining traditional and modern diagnostic methods. Finally, we recognize the need for increased capacity of centralized databases, networks, data repositories and contingency plans for diagnosis and management of marine disease.
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Affiliation(s)
- Colleen A Burge
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, 701 E Pratt Street, Baltimore, MD 21202, USA
| | - Carolyn S Friedman
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98195, USA
| | - Rodman Getchell
- Department of Microbiology and Immunology, C4-177 Vet Med Center, College of Veterinary Medicine, Cornell University, 930 Campus Road, Ithaca, NY 14853, USA
| | - Marcia House
- Northwest Indian Fisheries Commission, 6730 Martin Way East, Olympia, WA 98516, USA
| | - Kevin D Lafferty
- US Geological Survey, Western Ecological Research Center, c/o Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - Laura D Mydlarz
- Department of Biology, University of Texas Arlington, 501 South Nedderman, Arlington, TX 76019, USA
| | - Katherine C Prager
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Tristan Renault
- Ifremer, Département Ressources Biologiques et Environnement, rue de l'Ile d'Yeu, 44311 Nantes Cedex 03, France
| | - Ikunari Kiryu
- National Research Institute of Aquaculture, Fisheries Research Agency, Mie 516-0193, Japan
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Green TJ, Raftos D, Speck P, Montagnani C. Antiviral immunity in marine molluscs. J Gen Virol 2015; 96:2471-2482. [DOI: 10.1099/jgv.0.000244] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Timothy J. Green
- Sydney Institute of Marine Science, Chowder Bay Road, Mosman, NSW 2088, Australia
- Department of Biological Sciences, Macquarie University, NSW 2109, Australia
| | - David Raftos
- Department of Biological Sciences, Macquarie University, NSW 2109, Australia
- Sydney Institute of Marine Science, Chowder Bay Road, Mosman, NSW 2088, Australia
| | - Peter Speck
- School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - Caroline Montagnani
- IFREMER, IHPE UMR 5244, Univ. Perpignan Via Domitia, CNRS, Univ. Montpellier, F-34095 Montpellier, France
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Barbosa Solomieu V, Renault T, Travers MA. Mass mortality in bivalves and the intricate case of the Pacific oyster, Crassostrea gigas. J Invertebr Pathol 2015. [PMID: 26210497 DOI: 10.1016/j.jip.2015.07.011] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Massive mortality outbreaks in cultured bivalves have been reported worldwide and they have been associated with infection by a range of viral and bacterial pathogens. Due to their economic and social impact, these episodes constitute a particularly sensitive issue in Pacific oyster (Crassostrea gigas) production. Since 2008, mortality outbreaks affecting C. gigas have increased in terms of intensity and geographic distribution. Epidemiologic surveys have lead to the incrimination of pathogens, specifically OsHV-1 and bacteria of the Vibrio genus, in particular Vibrio aestuarianus. Pathogen diversity may partially account for the variability in the outcome of infections. Host factors (age, reproductive status...) including their genetic background that has an impact on host susceptibility toward infection, also play a role herein. Finally, environmental factors have significant effects on the pathogens themselves, on the host and on the host-pathogen interaction. Further knowledge on pathogen diversity, classification, and spread, may contribute toward a better understanding of this issue and potential ways to mitigate the impact of these outbreaks.
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Affiliation(s)
- Valérie Barbosa Solomieu
- Université de Bretagne Occidentale, Direction Europe et International, Présidence, 3 rue des Archives, CS93837, 29238 Brest CEDEX 3, France
| | - Tristan Renault
- Ifremer, Unité Santé Génétique Microbiologie des Mollusques (SG2M), Laboratoire de Génétique et Pathologie des Mollusques Marins (LGPMM), 17390 La Tremblade, France.
| | - Marie-Agnès Travers
- Ifremer, Unité Santé Génétique Microbiologie des Mollusques (SG2M), Laboratoire de Génétique et Pathologie des Mollusques Marins (LGPMM), 17390 La Tremblade, France
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Dégremont L, Lamy JB, Pépin JF, Travers MA, Renault T. New Insight for the Genetic Evaluation of Resistance to Ostreid Herpesvirus Infection, a Worldwide Disease, in Crassostrea gigas. PLoS One 2015; 10:e0127917. [PMID: 26039375 PMCID: PMC4454582 DOI: 10.1371/journal.pone.0127917] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 04/20/2015] [Indexed: 11/19/2022] Open
Abstract
The Pacific oyster, Crassostrea gigas, is the most important commercial oyster species cultivated in the world. Meanwhile, the ostreid herpesvirus 1 (OsHV-1) is one of the major pathogens affecting the Pacific oyster, and numerous mortality outbreaks related to this pathogen are now reported worldwide. To assess the genetic basis of resistance to OsHV-1 infection in spat C. gigas and to facilitate breeding programs for such a trait, if any exist, we compared the mortality of half- and full-sib families using three field methods and a controlled challenge by OsHV-1 in the laboratory. In the field, three methods were tested: (A) one family per bag; (B) one family per small soft mesh bag and all families inside one bag; (C) same as the previous methods but the oysters were individually labelled and then mixed. The mean mortality ranged from 80 to 82% and was related to OsHV-1 based on viral DNA detection. The narrow-sense heritability for mortality, and thus OsHV-1 resistance, ranged from 0.49 to 0.60. The high positive genetic correlations across the field methods suggested no genotype by environment interaction. Ideally, selective breeding could use method B, which is less time- and space-consuming. The narrow sense heritability for mortality under OsHV-1 challenge was 0.61, and genetic correlation between the field and the laboratory was ranged from 0.68 to 0.75, suggesting a weak genotype by environment interaction. Thus, most of families showing the highest survival performed well in field and laboratory conditions, and a similar trend was also observed for families with the lowest survival. In conclusion, this is the first study demonstrating a large additive genetic variation for resistance to OsHV-1 infection in C. gigas, regardless of the methods used, which should help in selective breeding to improve resistance to viral infection in C. gigas.
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Affiliation(s)
- Lionel Dégremont
- Institut Français de Recherche pour l’Exploitation de la Mer, Laboratoire de Génétique et de Pathologie des Mollusques Marins, Avenue Mus de Loup, La Tremblade, France
| | - Jean-Baptiste Lamy
- Institut Français de Recherche pour l’Exploitation de la Mer, Laboratoire de Génétique et de Pathologie des Mollusques Marins, Avenue Mus de Loup, La Tremblade, France
| | - Jean-François Pépin
- Institut Français de Recherche pour l’Exploitation de la Mer, Laboratoire Environnement Ressources des Pertuis Charentais, Avenue Mus de Loup, La Tremblade, France
| | - Marie-Agnès Travers
- Institut Français de Recherche pour l’Exploitation de la Mer, Laboratoire de Génétique et de Pathologie des Mollusques Marins, Avenue Mus de Loup, La Tremblade, France
| | - Tristan Renault
- Institut Français de Recherche pour l’Exploitation de la Mer, Laboratoire de Génétique et de Pathologie des Mollusques Marins, Avenue Mus de Loup, La Tremblade, France
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Dégremont L, Garcia C, Allen SK. Genetic improvement for disease resistance in oysters: A review. J Invertebr Pathol 2015; 131:226-41. [PMID: 26037230 DOI: 10.1016/j.jip.2015.05.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 05/12/2015] [Accepted: 05/13/2015] [Indexed: 10/23/2022]
Abstract
Oyster species suffer from numerous disease outbreaks, often causing high mortality. Because the environment cannot be controlled, genetic improvement for disease resistance to pathogens is an attractive option to reduce their impact on oyster production. We review the literature on selective breeding programs for disease resistance in oyster species, and the impact of triploidy on such resistance. Significant response to selection to improve disease resistance was observed in all studies after two to four generations of selection for Haplosporidium nelsoni and Roseovarius crassostrea in Crassostrea virginica, OsHV-1 in Crassostrea gigas, and Martelia sydneyi in Saccostrea glomerata. Clearly, resistance in these cases was heritable, but most of the studies failed to provide estimates for heritability or genetic correlations with other traits, e.g., between resistance to one disease and another. Generally, it seems breeding for higher resistance to one disease does not confer higher resistance or susceptibility to another disease. For disease resistance in triploid oysters, several studies showed that triploidy confers neither advantage nor disadvantage in survival, e.g., OsHV-1 resistance in C. gigas. Other studies showed higher disease resistance of triploids over diploid as observed in C. virginica and S. glomerata. One indirect mechanism for triploids to avoid disease was to grow faster, thus limiting the span of time when oysters might be exposed to disease.
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Affiliation(s)
- Lionel Dégremont
- SG2M, LGPMM, Ifremer, Avenue Mus de Loup, 17390 La Tremblade, France.
| | - Céline Garcia
- SG2M, LGPMM, Ifremer, Avenue Mus de Loup, 17390 La Tremblade, France.
| | - Standish K Allen
- Aquaculture Genetics and Breeding Technology Center, Virginia Institute of Marine Science, College of William and Mary, 1208 Greate Road, Gloucester Point, VA 23062-1346, USA.
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43
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Bai C, Wang C, Xia J, Sun H, Zhang S, Huang J. Emerging and endemic types of Ostreid herpesvirus 1 were detected in bivalves in China. J Invertebr Pathol 2015; 124:98-106. [DOI: 10.1016/j.jip.2014.11.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 11/17/2014] [Accepted: 11/25/2014] [Indexed: 12/11/2022]
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Evans O, Paul-Pont I, Hick P, Whittington R. A simple centrifugation method for improving the detection of Ostreid herpesvirus-1 (OsHV-1) in natural seawater samples with an assessment of the potential for particulate attachment. J Virol Methods 2014; 210:59-66. [DOI: 10.1016/j.jviromet.2014.09.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 09/20/2014] [Accepted: 09/24/2014] [Indexed: 10/24/2022]
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45
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Domeneghetti S, Varotto L, Civettini M, Rosani U, Stauder M, Pretto T, Pezzati E, Arcangeli G, Turolla E, Pallavicini A, Venier P. Mortality occurrence and pathogen detection in Crassostrea gigas and Mytilus galloprovincialis close-growing in shallow waters (Goro lagoon, Italy). FISH & SHELLFISH IMMUNOLOGY 2014; 41:37-44. [PMID: 24909498 DOI: 10.1016/j.fsi.2014.05.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 05/13/2014] [Accepted: 05/15/2014] [Indexed: 06/03/2023]
Abstract
The complex interactions occurring between farmed bivalves and their potential pathogens in the circumstances of global climate changes are current matter of study, owing to the recurrent production breakdowns reported in Europe and other regions of the world. In the frame of Project FP7-KBBE-2010-4 BIVALIFE, we investigated the occurrence of mortality and potential pathogens during the Spring-Summer transition in Crassostrea gigas and Mytilus galloprovincialis cohabiting in the shallow waters of one northern Italian lagoon (Sacca di Goro, Adriatic Sea) and regarded as susceptible and resistant species, respectively. In 2011, limited bivalve mortality was detected in the open-field trial performed with 6-12 month old spat whereas subsequent trials with 2-3 month old spat produced almost complete (2012) and considerable (2013) oyster mortality. Macroscopical examination and histology excluded the presence of notifiable pathogens but, in the sampling preceding the massive oyster spat mortality of 2012, a μdeleted variant of OsHV-1 DNA was found in wide-ranging amounts in all analyzed oysters in conjunction with substantial levels of Vibrio splendidus and Vibrio aestuarianus. The large oyster spat mortality with borderline OsHV-1 positivity recorded in 2013 supports the multi-factorial etiology of the syndrome. This is the first report of a OsHV-1 (under a form interpreted as the variant μVar) in the Goro lagoon. Transcriptional host footprints are under investigation to better understand the bivalve response to environmental factors, included viral and bacterial pathogens, in relation to the observed mortalities.
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Affiliation(s)
| | - Laura Varotto
- Department of Biology, University of Padova, Padova, Italy
| | - Michele Civettini
- Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe, also NRL for Mollusc Diseases), Adria, Italy
| | - Umberto Rosani
- Department of Biology, University of Padova, Padova, Italy
| | - Monica Stauder
- Department of Earth, Environmental and Life Sciences, University of Genova, Italy
| | - Tobia Pretto
- Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe, also NRL for Mollusc Diseases), Adria, Italy
| | - Elisabetta Pezzati
- Department of Earth, Environmental and Life Sciences, University of Genova, Italy
| | - Giuseppe Arcangeli
- Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe, also NRL for Mollusc Diseases), Adria, Italy
| | | | | | - Paola Venier
- Department of Biology, University of Padova, Padova, Italy.
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Segarra A, Baillon L, Tourbiez D, Benabdelmouna A, Faury N, Bourgougnon N, Renault T. Ostreid herpesvirus type 1 replication and host response in adult Pacific oysters, Crassostrea gigas. Vet Res 2014; 45:103. [PMID: 25294338 PMCID: PMC4198667 DOI: 10.1186/s13567-014-0103-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 09/24/2014] [Indexed: 11/10/2022] Open
Abstract
Since 2008, massive mortality outbreaks associated with OsHV-1 detection have been reported in Crassostrea gigas spat and juveniles in several countries. Nevertheless, adult oysters do not demonstrate mortality in the field related to OsHV-1 detection and were thus assumed to be more resistant to viral infection. Determining how virus and adult oyster interact is a major goal in understanding why mortality events are not reported among adult Pacific oysters. Dual transcriptomics of virus-host interactions were explored by real-time PCR in adult oysters after a virus injection. Thirty-nine viral genes and five host genes including MyD88, IFI44, IkB2, IAP and Gly were measured at 0.5, 10, 26, 72 and 144 hours post infection (hpi). No viral RNA among the 39 genes was detected at 144 hpi suggesting the adult oysters are able to inhibit viral replication. Moreover, the IAP gene (oyster gene) shows significant up-regulation in infected adults compared to control adults. This result suggests that over-expression of IAP could be a reaction to OsHV-1 infection, which may induce the apoptotic process. Apoptosis could be a main mechanism involved in disease resistance in adults. Antiviral activity of haemolymph against herpes simplex virus (HSV-1) was not significantly different between infected adults versus control.
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Affiliation(s)
- Amélie Segarra
- Ifremer (Institut Français de Recherche pour l'Exploitation de la Mer), Unité Santé Génétique et Microbiologie des Mollusques (SG2M), Laboratoire de Génétique et Pathologie des Mollusques Marins (LGPMM), Avenue de Mus de Loup, 17390, La Tremblade, France.
| | - Laury Baillon
- Ifremer (Institut Français de Recherche pour l'Exploitation de la Mer), Unité Santé Génétique et Microbiologie des Mollusques (SG2M), Laboratoire de Génétique et Pathologie des Mollusques Marins (LGPMM), Avenue de Mus de Loup, 17390, La Tremblade, France.
| | - Delphine Tourbiez
- Ifremer (Institut Français de Recherche pour l'Exploitation de la Mer), Unité Santé Génétique et Microbiologie des Mollusques (SG2M), Laboratoire de Génétique et Pathologie des Mollusques Marins (LGPMM), Avenue de Mus de Loup, 17390, La Tremblade, France.
| | - Abdellah Benabdelmouna
- Ifremer (Institut Français de Recherche pour l'Exploitation de la Mer), Unité Santé Génétique et Microbiologie des Mollusques (SG2M), Laboratoire de Génétique et Pathologie des Mollusques Marins (LGPMM), Avenue de Mus de Loup, 17390, La Tremblade, France.
| | - Nicole Faury
- Ifremer (Institut Français de Recherche pour l'Exploitation de la Mer), Unité Santé Génétique et Microbiologie des Mollusques (SG2M), Laboratoire de Génétique et Pathologie des Mollusques Marins (LGPMM), Avenue de Mus de Loup, 17390, La Tremblade, France.
| | - Nathalie Bourgougnon
- Université de Bretagne Sud (UBS), Centre d'Enseignement et de Recherche Yves Coppens, Laboratoire de Biotechnologie et Chimie Marines EA3884 (LBCM), Université Européenne de Bretagne (UEB), Campus de Tohannic, BP573, 56017, Vannes Cedex, France.
| | - Tristan Renault
- Ifremer (Institut Français de Recherche pour l'Exploitation de la Mer), Unité Santé Génétique et Microbiologie des Mollusques (SG2M), Laboratoire de Génétique et Pathologie des Mollusques Marins (LGPMM), Avenue de Mus de Loup, 17390, La Tremblade, France.
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Normand J, Blin JL, Jouaux A. Rearing practices identified as risk factors for ostreid herpesvirus 1 (OsHV-1) infection in Pacific oyster Crassostrea gigas spat. DISEASES OF AQUATIC ORGANISMS 2014; 110:201-211. [PMID: 25114044 DOI: 10.3354/dao02756] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Early detection of Pacific oyster spat infected with ostreid herpesvirus 1 (OsHV-1) could prevent introduction of OsHV-1-infected individuals into farming areas or onshore rearing facilities, thus reducing the risk of infection of naïve oysters in such production systems. Experiments were conducted on several hundred oyster spat provided by producers in order to examine whether early rearing practices could be considered as potential risk factors for (1) OsHV-1 infection as detected by molecular methods and (2) spat mortality experimentally induced through thermal challenge. Spat groups collected on oyster beds and hatchery spat reared in growout areas during summer exhibited higher viral DNA contamination and mortalities during the trial than spat kept in onshore rearing facilities. Quantification of viral DNA before and during the trial showed that infection prevalence and intensity changed over time and revealed latent infection initially unsuspected in 3 of 10 groups. Thermal challenge induced a clear increase in the probability of detecting infected individuals, particularly for groups exhibiting significant prevalence of OsHV-1-contaminated spat prior to the challenge. The use of detection methods are discussed in relation to early rearing practices and disease control strategies.
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Affiliation(s)
- Julien Normand
- Centre de Référence sur l'Huître, Université de Caen Basse Normandie, Caen, France
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Keeling SE, Brosnahan CL, Williams R, Gias E, Hannah M, Bueno R, McDonald WL, Johnston C. New Zealand juvenile oyster mortality associated with ostreid herpesvirus 1-an opportunistic longitudinal study. DISEASES OF AQUATIC ORGANISMS 2014; 109:231-239. [PMID: 24991849 DOI: 10.3354/dao02735] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
During the 2010-11 summer outbreak of ostreid herpesvirus 1 (OsHV-1) in New Zealand, an opportunistic longitudinal field study was conducted. OsHV-1 PCR-negative oyster spat (Crassostrea gigas) were relocated to an OsHV-1 PCR-positive area of the North Island of New Zealand that was experiencing juvenile oyster mortalities. Over a period of 13 d, spat were monitored for mortality, sampled for histopathology, and tested for the presence of OsHV-1 using real time PCR and Vibrio culture. Histopathology showed some evidence of tissue pathology; however, no consistent progressive pathology was apparent. Field mortalities were evident from Day 6 on. After 5 and 7 d of exposure, 83 and 100% of spat, respectively, tested positive for the virus by real time PCR. Vibrio species recovered during the longitudinal study included V. splendidus and V. aestuarianus. This study offers insight into the rapidity of onset and virulence of the virus in naïve oyster spat in New Zealand waters.
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Affiliation(s)
- S E Keeling
- Animal Health Laboratory, Investigation and Diagnostic Centre-Wallaceville, Ministry for Primary Industries, 66 Ward St, PO Box 40742, Upper Hutt 5018, New Zealand
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Ostreid herpesvirus 1 infection among Pacific oyster (Crassostrea gigas) Spat: relevance of water temperature to virus replication and circulation prior to the onset of mortality. Appl Environ Microbiol 2014; 80:5419-26. [PMID: 24973071 DOI: 10.1128/aem.00484-14] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A number of bivalve species worldwide, including the Pacific oyster, Crassostrea gigas, have been affected by mass mortality events associated with herpesviruses, resulting in significant losses. A particular herpesvirus was purified from naturally infected larval Pacific oysters, and its genome was completely sequenced. This virus has been classified as Ostreid herpesvirus 1 (OsHV-1) within the family Malacoherpesviridae. Since 2008, mass mortality outbreaks among C. gigas in Europe have been related to the detection of a variant of OsHV-1 called μVar. Additional data are necessary to better describe mortality events in relation to environmental-parameter fluctuations and OsHV-1 detection. For this purpose, a single batch of Pacific oyster spat was deployed in 4 different locations in the Marennes-Oleron area (France): an oyster pond ("claire"), a shellfish nursery, and two locations in the field. Mortality rates were recorded based on regular observation, and samples were collected to search for and quantify OsHV-1 DNA by real-time PCR. Although similar massive mortality rates were reported at the 4 sites, mortality was detected earlier in the pond and in the nursery than at both field sites. This difference may be related to earlier increases in water temperature. Mass mortality was observed among oysters a few days after increases in the number of PCR-positive oysters and viral-DNA amounts were recorded. An initial increment in the number of PCR-positive oysters was reported at both field sites during the survey in the absence of significant mortality. During this period, the water temperature was below 16°C.
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50
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Green TJ, Montagnani C, Benkendorff K, Robinson N, Speck P. Ontogeny and water temperature influences the antiviral response of the Pacific oyster, Crassostrea gigas. FISH & SHELLFISH IMMUNOLOGY 2014; 36:151-157. [PMID: 24200990 DOI: 10.1016/j.fsi.2013.10.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 10/24/2013] [Accepted: 10/25/2013] [Indexed: 06/02/2023]
Abstract
Disease is caused by a complex interaction between the pathogen, environment, and the physiological status of the host. Determining how host ontogeny interacts with water temperature to influence the antiviral response of the Pacific oysters, Crassostrea gigas, is a major goal in understanding why juvenile Pacific oysters are dying during summer as a result of the global emergence of a new genotype of the Ostreid herpesvirus, termed OsHV-1 μvar. We measured the effect of temperature (12 vs 22 °C) on the antiviral response of adult and juvenile C. gigas injected with poly I:C. Poly I:C up-regulated the expression of numerous immune genes, including TLR, MyD88, IκB-1, Rel, IRF, MDA5, STING, SOC, PKR, Viperin and Mpeg1. At 22 °C, these immune genes showed significant up-regulation in juvenile and adult oysters, but the majority of these genes were up-regulated 12 h post-injection for juveniles compared to 26 h for adults. At 12 °C, the response of these genes was completely inhibited in juveniles and delayed in adults. Temperature and age had no effect on hemolymph antiviral activity against herpes simplex virus (HSV-1). These results suggest that oysters rely on a cellular response to minimise viral replication, involving recognition of virus-associated molecular patterns to induce host cells into an antiviral state, as opposed to producing broad-spectrum antiviral compounds. This cellular response, measured by antiviral gene expression of circulating hemocytes, was influenced by temperature and oyster age. We speculate whether the vigorous antiviral response of juveniles at 22 °C results in an immune-mediated disorder causing mortality.
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Affiliation(s)
- Timothy J Green
- School of Biological Sciences and Australian Seafood Cooperative Research Centre, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia.
| | - Caroline Montagnani
- Ifremer, UMR 5119 Ecology of Coastal Marine Systems, Université Montpellier 2, Place Eugène Bataillon, CC80, 30495 Montpellier cedex 05, France
| | - Kirsten Benkendorff
- Marine Ecology Research Centre, Southern Cross University, P.O. Box 157, Lismore, NSW 2480, Australia
| | - Nick Robinson
- School of Biological Sciences and Australian Seafood Cooperative Research Centre, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia; Nofima, P.O. Box 210, N-1431 Ås, Norway
| | - Peter Speck
- School of Biological Sciences and Australian Seafood Cooperative Research Centre, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
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