QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online July 20, 2007
Journal of Experimental Biology 210, 2691-2699 (2007)
Published by The Company of Biologists 2007
doi: 10.1242/jeb.003715

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Fraser, K. P. P. Articles by Peck, L. S. Search for Related Content PubMed PubMed Citation Articles by Fraser, K. P. P. Articles by Peck, L. S. Social Bookmarking                         What's this?

Growth in the slow lane: protein metabolism in the Antarctic limpet Nacella concinna (Strebel 1908)

Keiron P. P. Fraser^*, Andrew Clarke and Lloyd S. Peck

British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 OET, UK

^* Author for correspondence (e-mail: kppf{at}bas.ac.uk)

Accepted 26 April 2007

Growth rates in Antarctic ectotherms are generally considered to be low in comparison to temperate and tropical species. Food consumption plays a major role in determining animal growth rates, but once food is ingested soft tissue growth rates are largely determined by the protein synthesis retention efficiency (PSRE), a measure of the efficiency with which proteins are synthesised and retained as protein growth. The effect of water temperatures on the PSRE of polar organisms has not previously been investigated, and it is possible that reduced PSRE at polar water temperatures may at least partially explain low growth rates in Antarctic organisms. We also currently lack any information on the potential effects of predicted increases in seawater temperatures on protein metabolism in Antarctic ectotherms. We have measured seasonal protein synthesis, degradation and growth rates in free-ranging Antarctic limpets (Nacella concinna), together with protein synthesis rates at temperatures ranging between –1.5°C and 6.0°C. PSRE were not significantly different in summer (15.69±4.41%) or winter (20.59±4.45%), but values were considerably lower than those previously reported in temperate and tropical species. A meta-analysis of published ectotherm PSRE suggested there was a positive relationship with temperature (y=449.9–114.9x, r²=28.8%, P<0.05). In turn, this suggests that temperature may be an important factor in determining ectotherm growth efficiency via an influence on PSRE. Maximal fractional and absolute protein synthesis rates occurred at 1°C in N. concinna, the approximate summer water temperature at the study site, and protein synthesis rates decreased above this temperature. In the absence of adaptation, predicted increases in Antarctic water temperatures would result in reduced, rather than increased, rates of protein synthesis and, in turn, possibly growth.

Key words: polar, limpet, growth, protein synthesis

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?