Memorial University DAI: Temporal changes in the fatty acid composition and fluidity of gill and hemocyte membranes during thermal acclimation of the sea scallop, Placopecten magellanicus

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Title	Temporal changes in the fatty acid composition and fluidity of gill and hemocyte membranes during thermal acclimation of the sea scallop, Placopecten magellanicus
Author	Hall, Jonathon Michael, 1971-
Description	Thesis (M.Sc.)--Memorial University of Newfoundland, 1999. Biology
Date	1999
Pagination	x, 90 leaves : ill.
Subject	Giant scallop--Effect of temperature on; Fatty acids
Degree	M.Sc.
Degree Grantor	Memorial University of Newfoundland. Dept. of Biology
Discipline	Biology
Language	eng
Notes	Bibliography: leaves 80-90
Abstract	The fatty acid composition and fluidity of gill phospholipids and hemocyte membranes of a eurytherrnal bivalve, Placopecten magellanicus, were investigated following a 10°C reduction in acclimation temperature. The time course of the acclimation response from 15 to 5°C was also monitored over a 21-day period. Membrane physical properties were measured by means of an electron spin resonance (ESR) spin-labeling technique, using 5- doxyl stearic acid (5-SASL) as a probe. Changes in the fluidity of gill membranes were analyzed by incorporating 5-SASL into vesicles made from total gill phospholipid (PL). Membrane fluidity measurements showed that cold-acclimated scallop membranes were more fluid than those of wann-acclimated animals. However, the order parameter of 5-SASL was greatest during the first six days of the reduction in temperature, indicating a more rigid gill membrane structure. The fluidity of gill and hemocyte membranes were negatively correlated with the proportion of 20:5n-3 (r = -0.714, P < 0.001, n = 24) and the unsaturated to saturated fetty acid ratio (r = -0.775, P < 0.05, n =8) respectively in the lipids of these tissues. Acclimation to reduced temperature for a prolonged period resulted in an increase in polyunsaturated fatty acid and a decrease in monounsaturated fatty acid content, in particular 20:5n-3 and Qq monoenoic fatty acids. Maximum changes in PL fatty acid levels required 15-21 days following acclimation to 5°C. Scallop gill and hemocyte membranes underwent progressive changes in their membrane fluidity and fatty acid composition, an observation which is consistent with homeoviscous adaptation following a reduction in acclimation temperature.
Type	Text
Resource Type	Electronic thesis or dissertation
Format	Image/jpeg; Application/pdf
Source	Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries
Local Identifier	a1358388
Rights	The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
Collection	Electronic Theses and Dissertations
Scanning Status	Completed
PDF File	(24.23 MB) -- http://collections.mun.ca/PDFs/theses/Hall_JonathonMichael.pdf
CONTENTdm file name	24663.cpd