The heat shock response of adult Artemia franciscana

Abstract

1. We studied responses of adult brine shrimp, Artemia franciscana, to high temperature, including LT 50 determination, induced thermotolerance (ITT), the Hsp-70 family of stress proteins and protein synthesis before and after heat shock. 2. Adults were grown in laboratory cultures from encysted embryos (cysts) obtained from San Francisco Bay (SF) and much warmer culture ponds in Vietnam (V). 3. Adults from V cysts were more tolerant of high temperatures than those from SF cysts, but this difference essentially disappeared in the second generation of adults. 4. Levels of constitutive Hsc-70 were very low in adults of both groups, but were strongly upregulated by a sublethal heat shock (37°C, 30 min), with V adults showing the greater degree of upregulation. Heat shock also induced Hsp-67, to a greater extent in V compared to SF adults 5. Incorporation of 14C-leucine into protein did not result in the “classic” heat shock response, possibly due to increased permeability of heat-shocked animals to the tracer.