Published in Integrative and Comparative Biology, Volume 52, Issue 1, January 6, 2012.
The porcelain crab Petrolisthes cinctipes inhabits the high intertidal along the Pacific coast between British Columbia and central California and is an emerging model organism to study the effects of environmental stress. In its habitat it experiences not only variability in average temperature but also variability in temperature fluctuations. To investigate the effect of temperature fluctuations, we characterized the heat shock response at 30°C for 6 h by acclimating individuals to three different acclimation treatments: 10°C, 10-20°C (4 h), and 10-30°C (4 h) on a daily basis for one month. We dissected claw muscle and separated proteins by 2D gel electrophoresis. Differences in protein expression patterns were identified based on a two-way ANOVA. We detected a total of 477 protein spots of which 67 showed an interaction effect between acclimation and heat stress. There were 80 and 135 proteins which showed a main effect for acclimation and heat stress, respectively. Proteins changing significantly were digested with trypsin, prepared for tandem mass spectrometry (MALDI TOF/TOF), and identified based on an expressed sequence tag library (Porcelain Crab Array Database). Several arginine kinase isoforms were up-regulated following heat shock without prior temperature fluctuations, but were not up-regulated following acclimation with fluctuations. Additionally, several energy metabolism enzymes were up-regulated following heat shock, but only when individuals were exposed to the 10-30°C acclimation. The results suggest that previous temperature fluctuations affect the acute heat shock response.