EVIDENCE FOR THE INDUCTION OF CYST DIAPAUSE BY HEAT-SHOCK IN ARTEMIA (INTERNATIONAL STUDY ON ARTEMIA, 48

The brine shrimp Artemia produces encysted embryos (cysts) in a state of obligate dormancy called diapause. Diapause is terminated by a vari ety of treatments, including dehydration. Previous work suggested that some cysts can be induced to reenter diapause when exposed to prolong ed anoxia. Results presented in this paper indicate that heat shock (4 2-43-degrees-C) can also lead to diapause induction. The basis for thi s proposal is the finding that the final hatching level of heat-shocke d cysts is increased by a postheat-shock dehydration, a treatment know n to terminate diapause. The respiration rate of postheat-shocked cyst s was found to be much lower than controls. Electrophoretic profiles o f proteins in extracts from control and heat-shocked cysts suggest tha t the intracellular translocation of a major protein accompanies heat shock.