Many venomous organisms produce toxins that disrupt neuromuscular communication to paralyze their prey. One common class of such toxins comprises nicotinic acetylcholine receptor antagonists (nAChRs). Thus, most toxins that act on nAChRs are targeted to the neuromuscular subtype. The toxin characterized in this report, alpha-conotoxin GIC, is a most striking exception. The 16-amino acid peptide...

Staphylococcus aureus and Streptococcus pyogenes colonize mucosal surfaces of the human body to cause disease. A group of virulence factors known as superantigens are produced by both of these organisms that allows them to cause serious diseases from the vaginal (staphylococci) or oral mucosa (streptococci) of the body. Superantigens interact with T cells and APCs to cause massive cytokine rele...

We previously have shown that alpha-adrenergic stimulation of canine Purkinje fibers and rat ventricle decreases automaticity. Experiments on rat ventricular myocytes in tissue culture have suggested that the decrease in automaticity induced by alpha-adrenergic stimulation depends on the development of sympathetic innervation and the presence of a pertussis toxin-sensitive, 41-kDa guanosine tri...

The protein toxin present in Bordetella pertussis vaccine blocks the inhibition of adenylate cyclase by prostaglandins and adenosine which may be secondary to ADP-ribosylation of an inhibitory guanine nucleotide-binding protein. The stimulatory effects of alpha 1-catecholamine agonists on 32P uptake into phosphatidic acid and phosphatidylinositol in isolated rat adipocytes were virtually abolis...

A chromosomal insertion of transposon Tn917 partially restores the expression of protease and alpha-toxin activities to PM466, a genetically defined agr-null derivative of the wild-type Staphylococcus aureus strain RN6390. In co-transduction experiments, transposon-encoded erythromycin resistance and a protease- and alpha-toxin-positive phenotype are transferred at high frequency from mutant st...

The effect of alpha-latrotoxin on cerebral cortex slices was studied by both biochemical and morphological methods. This toxin greatly stimulates the release of preloaded gamma-amino[3H]butyric acid from cortex slices. The response increases linearly with dose. The release is not dependent on the presence of extracellular Ca2+, and therefore it is not mediated by the release of other transmitte...

Bovine necro-haemorrhagic enteritis is an economically important disease caused by Clostridium perfringens type A strains. The disease mainly affects calves under intensive rearing conditions and is characterized by sudden death associated with small intestinal haemorrhage, necrosis and mucosal neutrophil infiltration. The common assumption that, when causing intestinal disease, C. perfringens ...

A major class of nicotinic receptors in the nervous system is one that binds alpha-bungarotoxin and contains the alpha7 gene product. PC12 cells, frequently used to study nicotinic receptors, express the alpha7 gene and have binding sites for the toxin, but previous attempts to elicit currents from the putative receptors have failed. Using whole-cell patch-clamp recording techniques and rapid a...

Oat seeds of cultivars susceptible and resistant to Helminthosporium victoriae were held for various times in pathogen-produced, host-specific toxin solutions; control seeds were in water. Seeds were then washed thoroughly and incubated on moist paper, or dried and stored for 2-3 weeks before germination was attempted. In both cases, germination of susceptible seeds was prevented by previous ex...

Fusion of antigenic proteins to Ig-binding proteins such as protein A from Staphylococcus aureus and its derived ZZ fragment is known to increase immunogenicity of the fused Ag in vivo. To shed light on the origin of this effect, we used snake toxins as Ags and observed that 1) fusion of toxins to ZZ enhanced their presentation to a toxin-specific T cell hybridoma (T1B2), using A20 B lymphoma c...