Neurotransmitter release involves the assembly of a heterotrimeric SNARE complex composed of the vesicle protein synaptobrevin (VAMP 2) and two plasma membrane partners, syntaxin 1 and SNAP-25. Calcium in¯ux is thought to control this process via Ca 2+ -binding proteins that associate with components of the SNARE complex. Ca 2+ /calmodulin or phospholipids bind in a mutually exclusive fashion to a C-terminal domain of VAMP (VAMP 77±90 ), and residues involved were identi®ed by plasmon resonance spectroscopy. Microinjection of wild-type VAMP 77±90 , but not mutant peptides, inhibited catecholamine release from chromaf®n cells monitored by carbon ®bre amperometry. Pre-incubation of PC12 pheochromocytoma cells with the irreversible calmodulin antagonist ophiobolin A inhibited Ca 2+ -dependent human growth hormone release in a permeabilized cell assay. Treatment of permeabilized cells with tetanus toxin light chain (TeNT) also suppressed secretion. In the presence of TeNT, exocytosis was restored by transfection of TeNT-resistant (Q 76 V, F 77 W) VAMP, but additional targeted mutations in VAMP 77±90 abolished its ability to rescue release. The calmodulin-and phospholipid-binding domain of VAMP 2 is thus required for Ca 2+ -dependent exocytosis, possibly to regulate SNARE complex assembly. Keywords: neuroendocrine cells/secretory vesicle/ SNARE/tetanus toxin IntroductionNeurones and neuroendocrine cells release transmitters and neuropeptides by calcium-dependent exocytosis of the contents of vesicles docked at the plasma membrane. This process requires assembly of trimeric SNARE complexes formed by the vesicle-associated membrane protein synaptobrevin (VAMP 2) and two partners that are expressed mainly in the plasma membrane, syntaxin 1 and synaptosome-associated protein of 25 kDa (SNAP-25) (reviewed by Jahn and Sudhof, 1999;Lin and Scheller, 2000;Mayer, 2001). Analysis of a minimal complex composed uniquely of the interacting domains of these three proteins has revealed a parallel bundle of four a-helices (one from VAMP 2, one from syntaxin 1 and two from SNAP-25) twisted into a superhelical structure (Sutton et al., 1998). Extrapolation of these data to a situation in which VAMP 2 and syntaxin 1/SNAP-25 are anchored in distinct lipid bilayers (i.e. docked vesicle membranes and plasma membranes, respectively) led to a proposal for trans SNARE complex function. The zippingup of SNARE complexes from the N-terminus to the C-terminus would pull the opposing C-terminal transmembrane anchors towards each other and promote membrane fusion at the vesicle±plasma membrane interface.Abundant evidence from the use of botulinum and tetanus toxins (BoNT and TeNT, respectively), which inhibit transmitter release by cleaving SNARE proteins (Xu et al., 1998;Hua and Charlton, 1999), as well as mutagenesis in invertebrates and mice (Fergestad et al., 2001;Schoch et al., 2001;Washbourne et al., 2002), have consolidated the view that SNARE proteins are required for exocytosis. However, the precise role of SNARE complex assembly in membr...

In the Mediterranean, Ostreopsis blooms induce skin and respiratory disorders when human beings are exposed to saltwater with a high concentration of algal cells. However, palytoxin dosages carried out on the food chain (urchins, mussels) indicate that this risk of toxins accumulation in seafood must be taken into account and that the surveillance network should be upgraded accordingly.

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There are very limited pre-clinical comparative data and no randomised controlled trials assessing effectiveness of the antivenoms against different Vipera species. Most descriptive data suggest the efficacy of Zagreb, ViperFAV and ViperaTAb antivenoms by the intravenous route but not intramuscular route, although this is level D evidence. Reported adverse reactions were rare, suggesting that the modern intravenous antivenoms are of good quality. Better and more systematic data, including perhaps randomized controlled trials comparing different antivenoms, are required for the many hundreds of antivenom administrations that occur annually across Europe.