The secretion of the ventral glands in Cladius, Priophorus and Trichiocampus sawfly larvae.

The volatile secretion from ventral glands of the larvae of Cladius pectinicornis, Priophorus morio, P. pallipes and Trichiocampus grandis was found to be principally composed of long-chain acetogenins, in majority of the esters and hydrocarbons, with more than 15 carbon atoms. The scarcity of more volatile compounds may be considered as plesiomorphic for the tribe Cladiini to which the four species belong. Further chemotaxonomic significance and chemical ecological implications of the glandular secretions are discussed. Moreover, the function of the well-developed pubescence covering the body of Cladiini larvae is discussed as a part of their defensive mechanism.

Enhancement of the endothelial production of prostacyclin by substituted derivatives of BAPTA-AM.

Our observation that loading of bovine aortic endothelial cells with quin 2 or 1,2-bis(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) enhances their release of prostacyclin (PGI2) has been studied in detail. The action of the acetoxymethyl ester (AM) of BAPTA (BAPTA-AM) was biphasic: at high concentrations (50 microM) and after prolonged exposure (60 min or more), it behaved as an inhibitor instead of an amplifier. Since inhibition could be related to calcium chelation, we tested 5,5'-difluoro-BAPTA-AM (5FBAPTA-AM), 4,4'-difluoro-BAPTA-AM (4FBAPTA-AM) and 5,5'-dibromo-BAPTA-AM (5BBAPTA-AM), whose corresponding free acids have a reduced affinity for Ca2+: these compounds were much more active in enhancing PGI2 production than BAPTA-AM itself. The effect of 5BBAPTA-AM was detectable at 0.5 microM and almost maximal at 5 microM (5-fold increase). 5BBAPTA-AM increased the release of free arachidonate induced by ATP but had no effect on the generation of inositol phosphates, the release of choline metabolites, and the accumulation of cAMP. 5BBAPTA-AM had a cytotoxic effect on the endothelial cells only after prolonged exposure to a high (50 microM) concentration. 5BBAPTA-AM inhibited the platelet production of thromboxane stimulated by a high (0.5 U/ml) concentration of thrombin and slightly potentiated the effect of a low (0.005 U/ml) concentration. In conclusion, the effect of 5BBAPTA-AM on the production of PGI2 seems to be rather specific to arachidonate metabolism in endothelial cells.