Physiological ecology
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Research study 1

Olympia oysters Ostrea conchaphila inhabit low intertidal to shallow subtidal regions along the west coast, and may be subject as adults to high temperatures during extreme low tides in summer.  Does exposure to high temperature induce a heat-shock response1 involving expression of protective “molecular-chaperone” proteins?  This aspect of O. lurida’s physiology is investigated by researchers at the Bodega Marine Laboratory, California along with the possibility that such heat-induced responses may also be present in early developmental2 stages.  Results show that expression of several Hsp proteins occurs in both adult and larval tissues (Hsp77, Hsp72, and Hsp69).  Expression in adults occurs at temperatures 33oC and above.  More importantly, expression of Hsp69 after a heat shock3 of 34oC leads to tolerance of otherwise lethal temperatures of 38-39oC.  As for the developmental stages, there is no heat-shock response in cleaving embryo or blastula stages, but Hsp69 is expressed in the veliger stage after exposure to a heat shock of 34oC.  Interestingly, the increased levels of Hsp69 in the larva persist for only a few hours, rather than for up to 3wk as in adults.  photograph of oysters Crassostrea gigas and Ostrea conchaphilaBrown et al. 2004 J Shellf Res 23 (1): 135.

NOTE1  expression of Hsp’s (heat-shock proteins) occurs in many intertidal invertebrates, including abalones, limpets, mussels, sea anemones, and others.  There are several types, categorized by their molecular masses

NOTE2  the authors note that Olympia oysters incubate their ealy life stages in the mantle cavity;  thus, these stages experience the same environmental conditions as do the brooding adults.  Later on, the veligers are released into the plankton 

NOTE3  this consists of 1h exposure to a given temperature, then a  return to ambient seawater

Japanese or Pacific oyster Crassostrea gigas
and Olympia oysters Ostrea conchaphila 0.6X

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