Download or read book Nuclear Receptors in the Pacific Oyster Crassostrea Gigas as Screening Tool for Determining Response to Environmental Contaminants written by Susanne Vogeler and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Summer Mortality of Pacific Oyster Crassostrea Gigas written by Jean-François Samain and published by Editions Quae. This book was released on 2008-02-13 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mass oyster mortalities have been known for many years throughout the world, but no strictly pathological explication has been found. This book describes how environmental influences, reproduction, stress, genetics, pathogens and temperature contribute to oyster summer mortality in France. An interaction model is derived from the results and recommendations are made for forecasting and managing risk factors.

Download or read book Biological Response of the Pacific Oyster Crassostrea Gigas to the South Australian Environment written by Benjamin Charles Baghurst and published by . This book was released on 2002 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biological Effects of Contaminants written by J. E. Thain and published by . This book was released on 1991 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Species Profiles written by Gilbert B. Pauley and published by . This book was released on 1988 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Epigenomic and Transcriptomic Regulation of Environmental Responses in the Pacific Oyster Crassostrea Gigas written by Mackenzie R. Gavery and published by . This book was released on 2014 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intertidal invertebrates such as bivalve molluscs live in constantly changing and frequently stressful environments and must be equipped to both detect and quickly respond to environmental changes. Our understanding of the molecular and cellular response systems in these organisms are an important part of species conservation and well as our ability to predict their response and limits to environmental stress. This dissertation explores environmental responses in oysters using transcriptomic and epigenomic approaches. The first chapter examines the transcriptomic responses of oysters from two locations with varying anthropogenic input using ultra short high-throughput sequencing reads. The work presented in Chapter 2 provides the first evidence that DNA methylation is present in the genome of a bivalve mollusc and suggests a regulatory role in these species. Chapter 3 provides the first whole methylome analysis of a locotrophozoan and identifies relationships between DNA methylation and gene expression. Finally, Chapter 4 presents a review of the current DNA methylation data available for bivalves and proposes new hypotheses for how DNA methylation may be regulating the genome in oysters. By combining transcriptional and epigenetic datasets, this work provides the most complete picture of epigenomic regulation for any molluscan species and paves the way into future investigations of the role of epigenetics in environmental regulation and local adaptation and evolution in marine invertebrates.

Download or read book Measured Effects of the Pacific Oyster Crassostrea Gigas on Water Quality for the Design of a Holding System written by Marcin Whitman and published by . This book was released on 1989 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Species Profiles written by Gilbert B. Pauley and published by . This book was released on 1988 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Influence of Environmental Factors Upon the Growth and Survival of the Pacific Oyster Crassostrea Gigas Thunberg microform written by James R. Brown and published by National Library of Canada. This book was released on 1986 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of the Deleterious Effects of Heavy Metals and Pesticides on Early Life Stages and Gametes of the Pacific Oyster Crassostrea Gigas written by Huong Mai and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The coastal areas are subject to multiple anthropogenic pressures including chemical pollution that can pose a real risk to the sustainability of aquatic species. The Arcachon Bay, macrotidal lagoon located on the French Atlantic coast, is the important ecosystem for oyster farming. But for several years, the oyster farms face lower recruitment and high mortality of oyster spat. Chemical contamination of the environment as a factor that may contribute to the observed effects on oysters has so far not been investigated.The present thesis aimed at evaluating through different approaches, of the potential toxicity of heavy metals and pesticides representative of the Arcachon Bay contamination on the early life stages of the Pacific oyster, Crassostrea gigas. Embryotoxicity, genotoxicity and expression levels of eleven targeted genes were studied. Firstly, different pesticides (S-metolachlor, irgarol, and diuron) and metals (copper and cadmium) were separately tested to determine their spectrum of effects. It were shown that exposure of gametes and embryos of oyster to environmental concentrations of pesticides and copper increased developmental abnormalities and DNA damage, and reduced fertilization success and affected offpring quality. Cadmium, meanwhile, showed no embryotoxic and genotoxic effects at the concentrations found in the Arcachon Bay. Metabolites of metolachlor, metolachlor ESA and metolachlor OA, are found in the Arcachon Bay at higher concentrations than their parent compound. The results showed that these metabolites were less embryotoxic and genotoxic on oyster embryos and spermatozoa than metolachor. Significant changes in expression of genes involved in antioxidant defense were observed for oyster larvae exposed to metolachlor and metolachlor ESA. Toxicity of mixtures of pesticides representative of the Arcachon Bay contamination with and without copper was then evaluated. Exposures of oyster embryos to these mixtures lead to development defects, DNA damage and changes in the expression of genes involved mainly in oxidative stress responses. Finally, mapping of toxicity of sediments from the Arcachon Bay was conducted for four seasons of 2011 with the oyster embryo-larvae assay. Sediments collected from Arguin exhibited low toxicity, regardless any season. In contrast, sediments from Le Tès showed higher toxicity in spring and summer seasons compared to winter season.From this work, it can be hypothesized that chemical contamination of the Arcachon Bay represents a threat for oyster reproduction and development.

Download or read book The Effects of Ocean Acidification on Multiple Life History Stages of the Pacific Oyster Crassostrea Gigas written by Emma B. Timmins-Schiffman and published by . This book was released on 2014 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: As global climate change accelerates, due in large part to increasing emissions of carbon dioxide and other greenhouse gases from fossil fuel use, agriculture, and large-scale changes in land use, natural ecosystems bear the consequences. For marine systems these include increased mean seawater temperature, changes in carbonate chemistry equilibria, and increased pollutant loading due to non-point run-off, among other effects. Human-induced environmental changes will not have the same magnitude of effect in all regions, but on average the changes occurring are rapid and significant. Natural populations will either need to acclimatize and/or adapt, or shift their ranges to enable continued existence. This dissertation explores the effects of ocean acidification on the Pacific oyster, Crassostrea gigas. Oysters are sedentary and inhabit a naturally variable environment (the intertidal zone) and thus may be pre-adapted to withstand rapid environmental change. Oysters and similarly sedentary organisms are ideal for investigating the effects of environmental change on biology because they are not able to escape these changes, but must respond physiologically (acclimatize) if they are to survive. Due to this ecological history, oysters provide a model that allows us to explore potential physiological mechanisms that are needed in a response to specific environmental changes as well as the limits of these mechanisms. In the first chapter, the effects of elevated partial pressure of CO2 (pCO2, a major driver of ocean acidification) on oyster larvae are explored. Larvae were exposed to low pH during early development, a period that included the transition from energetic dependence on maternally derived lipids to dependence on exogenous resources. Larvae were found to experience a developmental delay at elevated pCO2, manifested as smaller size and slower rate of shell deposition. These significant effects of ocean acidification on early larval development may indicate a bottleneck in the oyster life cycle as the pH of marine waters decreases. Subsequent research has shown that these effects at early larval stages can carry over into later stages after settlement in another oyster species (Hettinger et al. 2012). In order to better understand the effects of environmental change on oyster physiology, we developed proteomic tools to explore changes in protein pathways in oyster gill (ctenidia) tissue. The second chapter explores the gill proteome (suite of expressed proteins) of adult oysters. Characterization of the proteome provides insight into the physiological mechanisms that may be available to the oyster during response to an environmental stress. The results revealed that the ctenidia proteome includes a diverse array of proteins that accomplish many functions and that it is a metabolically active tissue. The proteome sequencing lays the groundwork for exploring how ocean acidification affects various proteomic pathways in the tissue that acts as the interface between the oyster and its environment. Lastly, the adult oyster response to ocean acidification and a second stress are explored via proteomics, fatty acid profiles, glycogen content, shell microstructure, and mortality in response to heat shock. There was a significant impact of ocean acidification on oyster shell integrity, but no effects after one month of exposure on relative amounts of fatty acid, glycogen or response to acute heat shock. Through the proteomic analysis, we revealed an active and significant proteomic response to ocean acidification exposure, uncovering some of the mechanisms behind the observed macro-phenotypic changes. Additionally, the proteomic response to mechanical stimulation was largely altered between low and high pCO2, suggesting that ocean acidification can fundamentally change how oysters respond to a second stress.

Download or read book Alien Species Alert written by Laurence Miossec and published by . This book was released on 2009 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ocean Acidification Influences on Physiology and Epigenetics in the Pacific Oyster Crassostrea Gigas written by Yaamini Ranjani Venkataraman and published by . This book was released on 2021 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: As ocean acidification continues to impact marine ecosystems at unprecedented rates, phenotypicplasticity may allow organisms to withstand more stressful conditions. Genomic methods can elucidate molecular mechanisms that contribute to phenotypic plasticity, allowing for a deeper understanding of how physiological processes will be impacted by low pH. My dissertation examines the effects of ocean acidification on the Pacific oyster (Crassostrea gigas) stress response and reproduction; elucidate how exposure history impacts phenotype; and explore the role of functional role DNA methylation in somatic and reproductive tissue. I investigated the effect of regional environmental variation on the molecular physiology of C. gigas outplanted at five different estuarine sites (four in Puget Sound, one in Willapa Bay) in Washington, USA using gel-free proteomic methods. While there was no difference in survival, or any protein abundances due to pH differences between sites, C. gigas outplanted at the site with the highest temperature had significantly higher abundances of antioxidant enzymes and molecular chaperones, elucidating the molecular underpinnings of thermotolerance. In a hatchery setting, I explored the impact of ocean acidification on reproductive maturity and output. A seven week low pH exposure did not affect sex ratio or maturation stage; however, it did significantly affect survival of larvae. Even though adult oysters spent four months in ambient pH conditions between low pH exposure and strip spawning, larvae from females that experienced low pH conditions had significantly higher mortality. Finally, I conducted the first investigations examining the effect of ocean acidification in C. gigas methylomes. To investigate the role of environmentally-responsive methylation in reproductive tissue, I analyzed gonad methylomes of female C. gigas exposed to low pH. A total of 1,599 differentially methylated loci (DML) were found in gene bodies. The genic DML were associated with cilium movement, development, and cytoskeletal processes, implying a need to regulate cellular growth in the gonad in response to low pH. I then explored the influence of low pH on the somatic tissue methylome using diploid and triploid oyster ctenidia. Differences in ploidy status yielded 154 DML. These ploidy-DML were associated with cell-cell adhesion and dephosphorlylation processes, which are not commonly associated with methylome changes in organisms that undergo natural polyploidization. The 178 pH-DML were associated with processes commonly observed in oysters exposed to ocean acidification, including apoptosis, protein ubiquitination, zinc ion binding, and cytoskeletal processes. In both reproductive and somatic tissue, the enrichment of DML in genes with multiple transcripts could indicate a role for methylation to regulate gene expression via alternative splicing. Investigating the molecular underpinnings of responses to ocean acidification in C. gigas will provide a thorough understanding of this global aquaculture product’s ability to withstand future ocean conditions.

Download or read book Ecophysiological Tolerances of the Pacific Oyster Crassostrea Gigas with Regard to the Potential Spread of Populations in South Australian Waters written by Kathryn Wiltshire and published by . This book was released on 2007 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Acute Nitrate Exposure Causes Proteomic Changes Consistent with the Regulation of Reactive Oxygen and Nitrogen Species in the Pacific Oyster Crassostrea Gigas written by Lauren R. Hitt and published by . This book was released on 2009 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: To test the physiological effects of nitrate on aquatic life, we exposed gill tissue of the Pacific oyster, Crassostrea gigas, to nitrate and characterized changes in protein expression, using a gel-based proteomics approach. 24 of 642 protein detected changed expression in response to a 6-hour exposure to NO3− (nitrate) concentrations ranging from 0-73 mg/L, values that characterize highly contaminated surface and ground waters. We propose that part of the cellular response to reactive nitrogen species is phagocytic hemocytes inhibiting the production of reactive oxygen species, potentially compromising the immune response of oysters to invading pathogens.

Download or read book Environmental Effects on the Physiology of Calcification in the Pacific Oyster Crassostrea Gigas Thunberg 1793 written by Frauke Bagusche and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Preliminary Observations on the Acute Inflammatory Reaction in the Pacific Oyster Crassostrea Gigas Thunberg written by Albert K. Sparks and published by . This book was released on 1965 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: