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Rebekah Thomas, Ph.D.
Associate Professor of Biology and Biomedical Sciences
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Education
- Ph.D. Physiology, University of Texas Health Science Center at San Antonio, August 1995. Dissertation Title: Transmembrane Chloride Distribution in Ehrlich Mouse Ascites Tumor Cells.
- B.A., Physiology and Anthropology, Magna Cum Laude, Metropolitan State College of Denver, May 1990.
Research Interests
I am interested in metabolic and generalized stress in animals and currently
am working on two areas.
1) Sportfishing for marine species such as the spotted seatrout
(Cynoscion nebulosus) is a multi-billion dollar industry. One goal of my
research is to assess negative impacts of hook and line capture on long-term
fitness which can be then used in the effective management of fisheries.
Recent regulations require release of capture fish, but studies that can
provide hard data as to the sublethal effects of releasing hook and line
captured fish are not available. Sublethal effects are those that would
result in reduced growth or rate of growth, or reduced reproductive output.
Fish undergo a number of physiological changes during the angling process
and the animals¹ ability to recover from those changes is the subject of
much debate. Of particular interest are the rise in blood lactic acid
concentration and plasma osmolality, and the disturbances in plasma chloride
concentration (an initial rise followed by a decrease below normal) that
occurs during and/or immediately following hook and line capture. There is
an abundance of literature that discusses the relationship of chloride to an
animal¹s ability to regulate cell volume. For vertebrates, cell volume
regulation, and therefore chloride regulation, is critical to those tissues
or organs whose responsibility it is to regulate organismal osmolality. In
fish, the ability to maintain organismal osmolality relies on the ability of
many cell types to regulate cell volume. Specifically we are using spotted
seatrout for this study.
2) The Eastern oyster, Crassostrea virginica, is an important
part of the ecosystem in the Gulf of Mexico. Dense aggregations of these
animals produce biogenic reefs that provide essential habitat for several
species of fish and invertebrates. Specifically, the complexity of these
reefs allows for a high nutrient availability while at the same time
providing adequate refuge that reduces the risk of predation for juvenile
fishes and invertebrates. Anthropogenic activities have reduced oyster reef
coverage in the Gulf of Mexico since the early 1800s. Over-harvesting due to
lack of harvest restrictions and habitat destruction due to dredging have
since caused a decline in the oyster population. Recent management
strategies have reduced the anthropogenic effects on oyster reefs, but the
reefs still currently occupy much less area than they did prior to the
1800s. One of the reasons for continued population fluctuation of oysters in
the Gulf of Mexico is the endoparasitic protozoan, Perkinsus marinus (Dermo). This protist infects the Eastern oyster and is prevalent in oysters
along the Texas Gulf Coast. It has been observed that oyster mortality due
to Dermo is more readily apparent in subtidal compared to intertidal
oysters. That is, it seems as though intertidal oysters can tolerate higher
levels of Dermo, thus acting as a reservoir for Dermo. We are currently
working on this problem and are looking at heat shock protein expression in
both subpopulations of oysters in the Corpus Christi Bay area as a potential
explanation for reduced effects of Dermo in intertidal oysters.
Publications
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Peer Reviewed
- Thomas-Young, R.J., T.C. Smith and C. Levinson. Regulatory volume decrease in Ehrlich ascites tumor cells is not mediated by a rise in intracellular calcium. Biochimica et Biophysica Acta, 1146: 81-86, 1993.
- Thomas-Young, R.J. and C. Levinson. Chloride accumulation in freshly isolated Ehrlich ascites tumor cells: the role of the Na/K/2Cl cotransporter. Biochimica et Biophysica Acta, 1280: 231-237, 1996.
- Abstracts
- Thomas-Young, R.J., L.C. Maxwell, R.A. deLemos and D.R. Gerstman. Lazaroid retards maturation of diaphragm muscle fibers after premature delivery. FASEB J., 5(6): A1742, 1991.
- Maxwell, L.C., R.J. Thomas-Young, R.A. deLemos and D.R. Gerstman. Ventilation with hyperoxia accelerates diaphragm muscle fiber maturation after premature delivery. FASEB J., 5(6): A1741, 1991.
- Thomas-Young, R.J., C. Levinson and T.C. Smith. Regulatory volume decrease occurs without an increase in intracellular Ca++ in Ehrlich ascites tumor cells. FASEB J., 6(5): A1747, 1992.
- Thomas-Young, R.J., and C. Levinson. The effect of an acid load on (Na-K-2Cl) cotransport and anion exchange in Ehrlich ascites tumor cells. FASEB J., 8(4): A23, 1994.
- Thomas-Young, R.J., and C. Levinson. Changes in cellular ionic composition in freshly isolated Ehrlich ascites tumor cells. FASEB J., 9(4): A635, 1995.
- Thomas, R.J. Lactate and pH sensitivity of the (Na:K:2Cl) cotransporter in freshly isolated Ehrlich ascites tumor cells. FASEB J., 14(4): A351, 2000.
All abstracts were presented at annual meetings of the Federation of American Societies for Experimental Biology (FASEB) in the year published in the FASEB Journal.
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