Mesocestoides lineatus: Trypsin induced development to adult mediated by Ca2+ and protein kinase C

Abstract A mode of action of the inducible treatment with trypsin for the development of Mesocestoides lineatus tetrathyridium to adult was analyzed by administering various agents effective on Ca 2+ -dependent metabolic pathways in the cells: protein kinase C activators such as a synthetic diacylglycerol, 1-oleoyl-2-acetylglycerol, and a tumor promoting phorbol, 12- O -tetra-decanoyl-phorbol-13-acetate, enhanced the trypsin induced developmental processes. On the contrary, a calmodulin inhibitor, N -(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide, cyclic adenosine 3′,5′-monophosphate, and adenylate cyclase activators such as forskolin and cholera toxin, inhibited the triggering action of trypsin. Furthermore, a combined administration of Ca 2+ ionophore (A23187) and the phorbol showed a similar effect with trypsin treatment, and sodium taurocholate acted as a potent enhancer like the activators of protein kinase C. These results strongly suggest that the initiation of development to adult in this cestode may be regulated synergistically by Ca 2+ and protein kinase C, and that a bile acid may be involved in an activation mechanism of protein kinase C.