Yuk-Ting Lau

Type

Text

Type

Dissertation

Advisor

Pales Espinosa, Emmanuelle | Allam, Bassem | Fast, Mark | Gomez-Chiarri, Marta | Mount, Andrew

Date

2017-12-01

Keywords

Marine biology | bivalve | crassostrea virginica | Cytology | Immunology | hemocyte | immunity | invertebrate | perkinsus marinus

Department

Department of Marine and Atmospheric Science

Language

en_US

Source

This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.

Identifier

http://hdl.handle.net/11401/78264

Publisher

The Graduate School, Stony Brook University: Stony Brook, NY.

Format

application/pdf

Abstract

The eastern oyster, Crassostrea virginica, is an economically- and ecologically-valuable species. Both commercial fisheries and ecological services are impacted by disease-associated mortality. Perkinsosis, caused by the protozoan parasite Perkinsus marinus, is one of the major diseases that cause mass mortalities. This dissertation aimed to investigate the role of oyster blood cells (hemocytes) in P. marinus infection. Hemocytes associated with mucosal surfaces lining the pallial (shell) cavity were characterized through functional assays and cell surface epitope labeling in conjunction with flow cytometry. Bi-directional transit of hemocytes across mucosal pallial epithelia was also evaluated using flow cytometry and fluorescence microscopy. In-vitro studies combining cell and molecular biology approaches were also performed to gain a better understanding of the effect of P. marinus on hemocyte motility. Finally, the regulation of apoptosis-related genes in hemocytes upon exposure to P. marinus was investigated to identify molecular cross-talk between the host and the parasite. Results showed that hemocytes associated with mucosal surfaces had distinct morphological, functional, and cell surface characteristics. Bi-directional migration of hemocytes between the pallial mucus and the circulatory system was observed. Exposure of pallial surfaces to P. marinus induced greater migration of hemocytes from the circulatory system to the pallial mucus layer and this response was pathogen-specific. In-vitro findings support the pathogen-specific increase in hemocyte motility and inhibitor experiments suggest the likely involvement of the Arp2/3 and integrin pathway in motility regulation by the parasite. P. marinus-induced regulation of the motility-related gene Arp2 and apoptosis-related genes (Bcl-2, anamorsin) in hemocytes and antioxidants (SOD and Prx) in P. marinus may be linked to cellular changes associated with the spread and establishment of the infection. This dissertation contributes to a better understanding of bivalve immunity and specifically to the mechanisms involved during the early infection process of C. virginica by P. marinus. | 170 pages

Download

Share

COinS