Rabbit antiserum against purified Electrophorus electricus acetylcholine receptor is studied using an immunoprecipitin assay to measure either antibody titer or concentration of toxin-binding sites in solubilized receptor preparations. This antiserum, unlike control serum, blocks the electrophysiological response of the electroplax to carbamylcholine. Toxin (alpha-neurotoxin, Naja naja) and sev...

[3H]Saxitoxin binds to a single class of receptor sites in rat brain synaptosomes and in broken membrane fractions derived from rat brain with a KD of approximately 2 11~ at 36°C. Batrachotoxin and scorpion toxin, which act at different receptor sites to activate sodium channels, have no effect on saxitoxin binding. Osmotic lysis and depolarization also have no effect on saxitoxin binding. Thes...

An efficient, single-step method for isolating highly purified toxin A from Clostridium difficile culture filtrates is described. The purification procedure was based on the affinity binding and release of toxin A to bovine thyroglobulin conjugated to agarose beads. The toxin strongly bound at 4 degrees C to the carbohydrate binding determinant Gal alpha 1-3Gal beta 1-4GlcNAc, a carbohydrate se...

Evidence is presented that endocytosis is involved in the transport to the cytosol of the cytotoxin from Shigella dysenteriae 1, Shiga toxin, which acts by removal of a single adenine residue in 28-S ribosomal RNA. Inhibition of endocytosis by ATP depletion of the cells prevented toxin uptake. Exposure of HeLa S3 and Vero cells to toxin at low extracellular pH, where translocation to the cytoso...

Summary Bacterial type II toxin-antitoxin (TA) modules encode a toxic protein that downregulates metabolism and specific antitoxin binds inhibits the toxin during normal growth. In non-typeable Haemophilus influenzae, common cause of infections in humans, vapXD locus was found to constitute functional TA module contribute pathogenicity; however, mode action VapD mechanism...

Tetanus toxin is known to bind neuronal tissue selectively. To study the interactions of this potent neurotoxin in an intact cell system, the binding of 125I-tetanus toxin was characterized in a neuroblastoma retina hybrid cell line, N18-RE-105. The binding of 125I-tetanus toxin to membranes prepared from N18-RE-105 cells showed many similarities to the interactions of 125I-toxin with rat synap...

The venom of the Eastern green mamba from Africa, Dendroaspis angusticeps, was found to block the binding of 3H-quinuclidinyl benzilate to pure m1 and m4 muscarinic ACh receptors expressed in Chinese hamster ovary cells. The principal toxin in the venom with anti-m1 muscarinic activity was purified by gel filtration and reversed-phase HPLC. This toxin has 64 amino acids, a molecular mass of 736...

The interaction of cholera toxin and a number of toxin derivatives, containing different proportions of light and heavy toxin-composing subunits (L and H), with mouse lymphocytes was studied. Experiments with [(125)I]toxin showed that a single cell can rapidly, within minutes, bind up to 40,000 molecules of toxin, the association constant was estimated to 7 +/- 4 x 10(8) liters/mol, and binding...