Meeting Abstract
P1.161 Friday, Jan. 4 The Proteomic Response of Tidally-entrained California Ribbed Mussel Mytilus californianus to Hypoxia Stress FOWLER, A*; ZUZOW, M; TOMANEK, L; California Polytechnic State University, San Luis Obispo; California Polytechnic State University, San Luis Obispo; California Polytechnic State University, San Luis Obispo aufowler@calpoly.edu
Rocky intertidal organisms experience extreme shifts in abiotic factors, such as hypoxia stress, due to tidal fluxes. During low tides, the California ribbed mussel (Mytilus californianus) normally closes its shell to avoid desiccation instead of gaping to augment gas exchange, and thus faces hypoxia stress and anaerobic metabolism. The energetic expense is met to some degree through a simultaneous down-regulation of metabolism. To characterize how entrainment to a tidal rhythm alone affects protein synthesis in M. californianus, mussels were acclimated to tidal conditions with a photoperiod (12 h:12 h) to mimic natural circadian rhythms. There were three treatment groups: a normoxic control, one treated with 100% nitrogen gas for 12 h followed by sampling at 24 and 72 h in which the mussels recovered under normoxic conditions, and a second 100% nitrogen treated group, which was exposed for 72 h to simulate long-term hypoxic conditions. During the long-term hypoxia treatment, gill tissue was extracted at 6, 12, 24, and 72 h. After dissection, the tissue was homogenized, proteins were precipitated, rehydrated and subsequently separated according to charge, using isoelectric focusing, and size, using 2D-gel electrophoresis. Gel images were analyzed with Delta2D to match spots across gels and quantify proteins, and then digested with trypsin to be identified with MALDI-TOF/TOF mass spectrometry. Tidally-entrained mussels responded to hypoxia by producing molecular chaperones and oxidative stress proteins during low tide. Research studying the physiological responses by intertidal invertebrates to the hypoxic response during low tide has the potential to elucidate the effects of interacting environmental stressors on tolerance limits.
