Fig. 6. Caspase inhibitors reduce the apoptosis-inducing effect of ISO on oyster hemocytes. (A) The pan-caspase inhibitor Z-VAD-FMK reduces the percentage of apoptotic cells among ISO-treated hemocytes, and (B) transfection of oyster hemocytes with a recombinant plasmid containing the baculovirus p35 gene under the transcriptional control of the gastropod hsp70 gene promoter (hsp p35) was able to reduce apoptosis among ISO-treated hemocytes. Control constructs containing the hsp70 gene promoter alone (hsp only) or the p35 gene alone (p35 only) had no significant effect on hemocyte ISO-induced apoptosis. Cells were maintained for 24 hours in the presence of 1 µM ISO or in the absence of drugs (Bas, basal level). Data are means and standard errors of three replicate experiments. Asterisks denote significant (P<0.01) differences from samples incubated in the presence of ISO alone.