Author : Yaamini Ranjani Venkataraman
Publisher :
ISBN 13 :
Total Pages : 147 pages
Book Rating : 4.:/5 (128 download)
Book Synopsis Ocean Acidification Influences on Physiology and Epigenetics in the Pacific Oyster (Crassostrea Gigas) by : Yaamini Ranjani Venkataraman
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.
