Meeting Abstract
Carcinus maenas, an intertidal species, faces daily variations of temperature and oxygen. Molecular pathways involved in stress response include genes expressed following energy depletion, hypoxia, and heat shock. Sirtuin stabilizes many transcription factors by deacetylation. High AMP:ATP ratio down regulates mTOR via AMP kinase (AMPk) to conserve cellular energy. Hypoxia triggers HIF transcription and upregulates hypoxia-sensitive genes. At elevated temperatures, HSP’s act as molecular chaperones to protect cellular proteins. Crabs shifted from ~14 ˚C to temperatures between 5 and 30 °C for 1 or 2 h. Also, green crabs were exposed to emersion-induced hypoxia ± desiccation for 2, 4, and 6 h. The responses of were determined using mRNA levels of AMPk, mTOR, Rheb, HIF, HSP70, and SIRT were used determine the responses of Y-organ, gill, heart, skeletal muscle, eyestalk ganglia (ESG), and thoracic ganglion (TG). C. maenas tolerated a wide temperature range, requiring 2-h exposures at 5 °C and 30 °C to affect gene expression. HSP70 increased in all tissues at 30 ˚C. Emersion alone had little or no effect on gene expression. Combined emersion/desiccation stress decreased gene expression by 6 h in heart and gill. In summary, high temperature and emersion with desiccation time upregulates AMPk and SIRT, downregulates mTOR, which would repress translation by relocating energy. Tissue response varied, with gill and heart more sensitive to stress than other tissues. Supported by NSF (IOS-1257732).
