Meeting Abstract

P1.79  Thursday, Jan. 3  Microarray analysis of thermal stress responses in porcelain crabs acclimated to different temperatures GALASSI*, E.W.*; STILLMAN, J.H.; San Francisco State University; San Francisco State University egalassi@sfsu.edu

Intertidal organisms experience extreme temperatures during low tides. We wished to understand the plasticity of transcriptome responses to thermal stress in porcelain crabs acclimated to warm and cold temperatures. Crabs acclimated to 8°, 14°, or 22°C were exposed to a short-term heat or cold thermal stress, or held at the acclimation temperature as a control, and sampled during recovery at their acclimation temperature. Tissue samples were dissected and frozen in liquid nitrogen during the first 24 hours of recovery. RNA was extracted, purified, reverse transcribed, and hybridized to cDNA microarray slides containing a library of 6,400 unique ESTs of Petrolisthes cinctipes. Each hybridization included a stress sample and a control sample of specimens from the same acclimation temperature. R/MAANOVA was used to identify microarray features that differed significantly between stress and control groups. We also compared heat stress and cold stress responses across acclimation temperatures by generating ratios of stress/control log lowess normalized data and comparing these ratios in the different acclimation temperatures. Sequences of many differentially expressed features matched the ESTs of hypothetical proteins or had no match to any proteins in the GenBank, Swiss-Prot, or Gene Ontology databases, suggesting that many genes involved in thermal acclimation remain uncharacterized. The most significant changes in gene expression were found to be between acclimation groups, and not between stress temperature and control groups, indicating that gene regulation in P. cinctipes may be influenced more by acclimation temperature than by stress responses. This work was funded by NSF 0533920 to JS.