Meeting Abstract

1.10  Monday, Jan. 4  Dynamics of Gene Regulation in the Penaeid Shrimp Litopenaeus vannamei Exposed to Hypoxia and Hypercapnic Hypoxia RATHBURN, CK*; SHARP, NJ; BURNETT, LE; BURNETT, KG; College of Charleston; College of Charleston; College of Charleston; College of Charleston kolo.rathburn@gmail.com

Many crustaceans inhabit estuarine ecosystems where they are frequently exposed to hypoxia (H) and elevated levels of CO₂ (hypercapnia). These factors may impair the abilities of crustaceans to maintain optimal metabolic processes and immune defense. Marine crustaceans employ various tactics to cope with environmental hypoxia and hypercapnia, which can involve metabolic depression possibly by regulating their gene expression. The present study tested the hypothesis that H and hypercapnic H (HH) elicit down-regulation of genes associated with metabolic depression, specifically protein synthesis and transcription, as well as immune defense. Shrimp were held in H, HH, or normoxia (N) for 4 h or 24 h. RNA from hepatopancreas of individual animals was hybridized to microarrays containing 21,864 unigenes expressed by L. vannamei. Transcriptional profiles of H and HH animals were compared to respective 4 and 24 h N controls. Genes involved in amino acid metabolism, RNA metabolism, and translation (including numerous tRNA synthetases) were down-regulated in 4 h H, 24 h H and 4 h HH shrimp. Few regulated genes could be assigned to immune defense, except for several in 24 h H shrimp, which included crustins and penaeidins. Additionally, unique patterns of gene expression such as increased lipid metabolism and initiation of apoptosis were tied to specific treatments and times, revealing effects of duration and added CO₂ stress in altering the transcriptome of L. vannamei. These results suggest that crustacean molecular responses to environmental changes in O₂ and CO₂ pressure involve both general and stress-specific gene sets and contribute insight to the effects human perturbations might have on estuarine organisms. Supported by NSF IBN-0212921 and NOAA OHH at HML.