11/02/2023
By Irma Silva

The Kennedy College of Sciences, Department of Biological Sciences, invites to you attend a Ph.D. Dissertation Defense by Erin Sullivan, entitled "The blood transcriptome, gene expression, and parasite communities of cold-stunned Kemp's ridley sea turtles from Cape Cod, Massachusetts, USA."

Candidate: Erin Sullivan
Degree: Doctoral
Date: Friday, Nov. 17
Time: 9 a.m. to noon
Location: Southwick Hall 240

Committee Members:

  • Jessica Garb, Biological Sciences, University of Massachusetts Lowell
  • Rick Hochberg, Biological Sciences, University of Massachusetts Lowell
  • Helen Poynton, University of Massachusetts Boston
  • Kathy Tuxbury, MS, DVM - New England Aquarium

Brief Abstract:
Kemp’s ridley turtles (Lepidochelys kempii) are a critically endangered sea turtle species, commonly occurring in North Atlantic waters in warm months. Juvenile turtles strand from cold-stunning in increasingly large numbers each winter, often on the coasts of Cape Cod, Massachusetts. Cold stunning, a phenomenon akin to prolonged hypothermia, incapacitates sea turtles and ultimately results in a myriad of injuries, illnesses, and distress. In this work, I characterized the helminth parasite intrapopulation of 38 deceased ridleys using both molecular (cytochrome c oxidase subunit 1 markers) and microscopic techniques. Every turtle examined exhibited some level of parasitic infection, and I observed a pattern of aggregation within the sampled animals. I found five species of nematodes from the genus Anisakis, as well as adult trematodes and one cestode (Hepatoxylon trichiuri). Additionally, I investigated differential gene expression (DGE) of 11 cold-stunned turtles upon intake to a rehabilitation facility compared to those same turtles in convalescence (once determined to be releasable some months later) using high-throughput sequencing technologies to generate the first Kemp’s ridley de novo transcriptome from blood cells. I compared overall DGE as well as investigated target genes of interest related to cold tolerance. Overall metabolic and immunologic processes appear reduced or arrested in cold-stunned turtles, while genes related to cell stability and proliferation are over-expressed under the same condition. Candidate genes related to hypoxia mitigation were over-expressed during cold-stunning, while heat shock proteins and antioxidants of varying types were upregulated in both conditions. This work may inform ways in which to evaluate stranded sea turtles for survivability and appropriateness of treatment. It also serves as an initial illustration of the gene regulatory processes that occur during cold-stunning in sea turtles.