No description available.

Sanguinolaria rostrata is a deep site-burrowing bivalve commonly found in the southwest coastal waters of Taiwan. It has a long siphon extending to the surface. It is reported that exposed S. rostrata dies in few days without silt. However trussing it up rubber bands or cut off the hinge, it can survive for over one month in the laboratory. In this study the relation of shell closing and mortality for S. rostrata were examined and compared with the hard clam Meretrix lusoria in the similar environments. The size of adductor muscle and its ratio to the shell size, the strength of shell closing and the tissue structure of adductor muscle were examined. The quantities of fructose 2,6- biphosphate, an intermediate of glycolysis, in the adductor muscle of S. rostrata were determined. The results indicated that the average strength of closing shell for S. rostrata was 36.65% and for M. lusoria was 41.19%. The trends of tropic shell closing strength and the size of adductor muscle as well as shell closing strength and the adductor muscle wet weight were the same for the two species. The ranges of strength for muscle closing among S. rostrata of different sizes were smaller than those of M. lusoria. The average ratio of the adductor muscle microfiber to muscle was 55.6¢Mfor S. rostrata and 83.2¢M for M. lusoria. Therefore, the adductor muscle of S. rostrata is looser to M. lusoria. The concentration of fructose 2,6- biphosphate fluctuated widely to the unclamped S. rostrata in the first 6 hours and the concentration reached 7.58£gmole/mg at most. The concentration did not rise between 6 and 24 hours, indicating that unclamped S. rostrata consumed energy within the first 6 hours, then showed no sign of consuming energy.

Increases in seawater temperatures have imposed physiological constraints which are partially thought to contribute to recently observed shifts in biogeographic distribution among closely related intertidal ectotherms. For instance, Mytilus galloprovincialis an introduced warm-adapted species from the Mediterranean, has displaced the native cold-adapted congener, M. trossulus, over large latitudinal expanses off the California coast. Several comparative physiological studies have revealed interspecific differences in thermal tolerance, including variation in aerobic metabolism and gape behavior, which suggest the invasive congener is better adapted to acclimate to increasing seawater conditions as predicted due to climate change. However, current analyses seek to discover the cellular process which contribute to thermal plasticity at the level of the whole organism in response to temperature stress. Since proteins represent the primary molecular machinery capable of responding to thermal stress, we quantified the proteomic response of the adductor muscles (AM) of M. galloprovincialis and M. trossulus to acute heat stress. After acclimation to 13°C, we exposed mussels to 24°C, 28°C and 32 °C (at a heating rate of 6C/h), kept mussels at the temperature for 1 h and then added a 24-h recovery period. Posterior adductor muscle samples were then excised and utilized for proteomic analysis. We were able to detect 273 protein spots within M. galloprovincialis and 286 protein spots within M. trossulus. Roughly 33% of these protein spots exhibited significant changes in abundance in response to heat stress within M. trossulus as compared to only 19% in M. galloprovincialis. In both data sets, most proteins changing abundance are part of the cytoskeleton or proteins controlling actin thin filament dynamics and stress fiber formation. Specifically, M. galloprovincialis increased the abundance of proteins involved in thin filament stabilization and cytoskeletal maintenance. In contrast, M. trossulus increased proteins involved in thin filament destabilization and filament turnover. In addition, only M. trossulus increased proteins involved in the cellular stress response at the highest temperature, suggesting its AM proteome is more thermolabile. In return, our results suggest that cytoskeletal architecture is more thermally stable in M. galloprovincialis. The differences in the proteomic responses suggest that M. galloprovincialis is capable of protecting itself from heat stress through valve closure at a higher temperature due to the increase in actin stabilizing proteins.