Meeting Abstract
Intertidal mussels of the genus Mytilus experience prolonged hypoxic and even anoxic conditions during aerial emersion (low tide), depending on the pattern of the semi-diurnal tidal cycle. Furthermore, mussels of M. trossulus, a native to the Pacific coast, are known to be more heat-sensitive than those of M. galloprovincialis, an invading species from the Mediterranean. It is presumed that heat-tolerance correlates closely with hypoxia tolerance, suggesting that M. galloprovincialis may be the more hypoxia-tolerant of the congeners, making it a successful invasive species . However, interspecific differences may also depend on the recent tidal history of the animals. Thus, to compare the proteomic responses of the two congeners, we acclimated both species to subtidal (constant emersion) and intertidal (6 h low: 6 h high tide) conditions for three weeks before exposing animals to 0, 6, 12, 24 and 120 h of aerial-induced hypoxia while also running a control under acclimation conditions. Changes in protein abundance in gill tissue collected during the experiment were analyzed with 2D GE and MALDI TOF/TOF. Preliminary analyses of the proteomic changes during hypoxia suggest that mussels greatly differ in how they modify the abundance of molecular chaperones of the endoplasmic reticulum (ER) and antioxidant proteins. The ER chaperones may be involved in the excretion of mucous by the gill tissue to capture food particles. Hypoxia may serve as a signal to the gill to reduce mucus production through down-regulation of ER chaperones. Protein expression patterns of tidally entrained mussels suggest a higher tolerance to hypoxia compared to their subtidally entrained counterparts.
