Meeting Abstract
The intertidal zone is a dynamic environment that fluctuates with the 12.4-h circatidal and 24-h circadian cycle to predictably alter food availability, temperature, air exposure, wave action, oxygen partial pressure, and osmotic conditions. Intertidal sessile bivalves exhibit behavioral or physiological changes such as adjusting gaping behavior and heart rate to cope with the persistent challenges of fluctuating environmental conditions. To date, transcriptomic studies on mussels’ baseline circadian and circatidal rhythms indicate that the circadian rhythm exerts a dominant entrainment of transcriptional patterns. However, as proteins reflect the basic molecular phenotype of the cell and their abundance may differ greatly from that of mRNA, transcriptional methods could fail to detect important cyclical changes in the proteome that cope with the regular stress of tidal rhythms. For this study, intertidal Mytilus californianus were acclimated to four treatment combinations of circadian (12:12 h light/dark cycle) and circatidal (6:6 h tidal cycle) conditions using a tidal simulator with identical feeding schedules. Following acclimation, mussels were sampled from each treatment every 2 h for 48 h and gill tissue was dissected and frozen for proteomic analysis using 2-D GE and MALDI TOF-TOF mass spectrometry. Preliminary data suggest that tidally-entrained mussels differ in antioxidant and NADPH-producing proteins, primarily near tidal transitions, as well as a shift to a new metabolic state with changing tides. This high-resolution time course of protein abundance patterns under differing circadian and circatidal cues is providing insights into the endogenous responses to tidal and circadian rhythms of the proteome.
