Meeting Abstract

P2.188  Monday, Jan. 5  Fatty acid composition of membranes and storage fat in the Eastern red spotted newt (Notophthalmus viridescens viridescens) BERNER, N.J.*; BULLOCK, J.R.; Sewanee:University of the South, Sewanee, TN nberner@sewanee.edu

Eastern red spotted newts acclimate enzyme activity and metabolic rate seasonally, in the laboratory and in the field. Winter and cold-acclimated newts have higher skeletal muscle cytochrome c oxidase (CCO) and citrate synthase activity and higher standard metabolic rates than summer and warm-acclimated newts. Membrane fatty acid (FA) composition can affect membrane-bound proteins such as CCO, and metabolic rate. We investigated the FA composition of muscle membranes to determine if changes in CCO activity could be due to changes in membrane FA composition. We are also interested in the regulation of membrane FA composition and remodeling, so we also determined the FA composition of storage fats (triglycerides and fat bodies). Finally, as diet also impacts FA composition, we determined the FA contents of the newt diets. Newts were collected in the field in January and July 2008, euthanized, dissected, stomach contents collected and samples stored at -80C. Laboratory newts were purchased in October 2008 from Amphibians of North America, and acclimated in the laboratory for 12 weeks (cold-acclimated 8C, 10:14; warm-acclimated 26C, 14:10) and fed mealworms (Tenebrio, sp). At the end of 12 weeks, newts were euthanized, dissected and stored at -80C. Lipids were extracted in methanol:chloroform (2:1 v/v). Phospholipids and triglycerides were separated on silica cartridges. These lipids were methylated using acetyl chloride in methanol:toluene (4:1 v/v). The FA methyl esters were separated by gas chromatography on a Varian 3900 with a fused silica column (100 m x 0.25 mm) with select FAME coating tailor made. Individual FAs were identified by comparing each peaks retention time with that of external standards, and FA content was expressed as mol% of total FA.