Thermotolerance and Hsp70 profiles in adult and embryonic California native oysters, Ostreola conchaphila

The oyster Ostreola conchaphila is endemic to shallow subtidal and low intertidal marine waters of the West coast of North America. The heat shock response of the species was characterized for both adult and early life stages. O. conchaphila expressed proteins that were the same molecular weights as and were immunologically related to the heat shock protein (Hsp)70 family of proteins that have been described for the oyster, Crassostrea gigas. Hsp77 and Hsp72 were present in adult and larval tissue. Expression of Hsp69 occurred in adults that were heat shocked at 33-38 degree C, regardless of season or previous environmental temperature regimen. A heat shock at 34 degree C induced thermotolerance to otherwise lethal temperatures of 38.5 degree or 39 degree C. Early lifestage embryos (early cleavage, late cleavage, and ciliated blastula stages) were unable to express Hsp69 or mount a heat shock response. Veliger larvae expressed Hsp69 after a 34 degree C heat shock. The increased Hsp69 persisted for at least 12 h after 1 h of heat shock as opposed to the acquisition of thermotolerance, which had declined by 12 h after heat shock.