Meeting Abstract
87.3 Friday, Jan. 7 Patterns of oxidative protein damage and gaping behavior following repeated heat stress in Mytilus mussels DOWD, WW*; SOMERO, GN; Hopkins Marine Station of Stanford University; Hopkins Marine Station of Stanford University wwdowd@stanford.edu
Intertidal mussels experience dramatic variations in temperature and oxygen availability (low during emersion, particularly when shells are closed). Such dynamic conditions, alone or in concert, may damage mussel proteins via several mechanisms: thermal denaturation, oxidative damage due to increased production of reactive oxygen species at warm temperatures, or reoxygenation injury. Using 2D Western blots for protein carbonylation, mass spectrometry, and biochemical methods, we are examining the amount, the specific targets, and the consequences of oxidative protein lesions following simulated tidal cycles in three Californian Mytilus congeners: the cold-adapted native blue mussel (M. trossulus), the warm-adapted invasive blue mussel (M. galloprovincialis), and the eurythermal ribbed mussel (M. californianus). These congeners differ in their behavioral response to simulated intertidal heat stress, with M. trossulus demonstrating a propensity to close completely in the face of heat stress as well as the greatest behavioral shift in the recovery phase after repeated heat stress events. Simultaneous measurements of mantle oxygen concentration demonstrate that periodic shell valve adductions create repeated reoxygenation events, particularly in the blue mussels, that may contribute to oxidative damage. Decreases in adductions following heat stress, particularly of complete closure events in M. trossulus, imply accumulation of oxidative damage during/after thermal stress and behavioral ‘unwillingness’ to undergo subsequent cycles of hypoxia and reoxygenation. We are currently examining patterns of susceptibility to oxidative protein damage following one or multiple heat stress episodes in these species to elucidate interactions among physiology, behavior, and evolutionary thermal history in intertidal species.
