| normal toxin | A toxin solution holding exactly 100 lethal doses in 1 ml. (05 Mar 2000) |
|---|---|
| diagnostic diphtheria toxin | Corynebacterium diphtheriae toxin diluted so that the inoculated dose (0.1 or 0.2 ml) will contain 1/50 th of guinea pig minimal lethal dose. See: Schick test. Synonym: diagnostic diphtheria toxin. (05 Mar 2000) |
| Dick test toxin | A culture filtrate of lysogenised group A strains of beta-haemolytic streptococci, erythrogenic when inoculated into the skin of susceptible persons, and neutralised by antibodies that appear during scarlet fever convalescence; three immunological types (A, B, and C) are recognised. Synonym: Dick test toxin, erythrogenic toxin, scarlet fever erythrogenic toxin. (05 Mar 2000) |
| dinoflagellate toxin | A potent neurotoxin that is thought to act similarly to botulinus toxin by impairing the synthesis or the release of acetylcholine. (05 Mar 2000) |
| diphtheria toxin | <protein> An ab exotoxin (62 kD) coded by _ corynephage of virulent Corynebacterium diphtheriae strains (that can produce a repressor of toxin production). The B subunit binds to receptors on the surface of the target cell and facilitates the entry of the enzymically active A subunit (21 kD) that ADP ribosylates elongation factor 2, thereby halting mRNA translation. (18 Nov 1997) |
| intracellular toxin | <protein> Heat stable polysaccharide like toxin bound to a bacterial cell. The term is used more specifically to refer to lipopolysaccharide (LPS) of the outer membrane of gram-negative bacteria. There are three parts to the molecule, the Lipid A (six fatty acid chains linked to two glucosamine residues), the core oligosaccharide (branched chain of ten sugars) and a variable length polysaccharide side chain (up to 40 sugar units in smooth forms) that can be removed without affecting the toxicity (rough LPS). Some endotoxin is probably released into the medium and endotoxin is responsible for many of the virulent effects of gram-negative bacteria. (18 Nov 1997) |
| t-2 toxin | <chemical> (3 alpha,4 beta,8 alpha)-12,13-epoxytrichothec-9-ene-3,4,8,15-tetrol 4,15-diacetate 8-(3-methylbutanoate). A potent mycotoxin produced in feedstuffs by several species of the genus fusarium. It elicits a severe inflammatory reaction in animals and has teratogenic effects. Chemical name: Trichothec-9-ene-3,4,8,15-tetrol, 12,13-epoxy-, 4,15-diacetate 8-(3-methylbutanoate), (3alpha,4beta,8alpha)- (12 Dec 1998) |
| tetanus toxin | <protein> Neurotoxin released by Clostridium tetani, becomes active when peptide cleaved proteolytically to heavy (100 kD) and light (50 kD) chains held together by disulphide bond. Heavy chain binds to disialogangliosides (GD2 and GD1b) and part of the peptide (the amino terminal B fragment) forms a pore: light chain is a zinc endopeptidase that specifically attacks synaptobrevin, to block neurotransmitters. See: botulinum toxin (18 Nov 1997) |
| toxin | <pharmacology> A poison, frequently used to refer specifically to a protein produced by some higher plants, certain animals and pathogenic bacteria, which is highly toxic for other living organisms. Such substances are differentiated from the simple chemical poisons and the vegetable alkaloids by their high molecular weight and antigenicity. Origin: Gr toxikon = arrow poison, from Gr. Toxikos = of or for a bow (18 Nov 1997) |
| toxin spectrum | A figure in the form of a spectrum used by Ehrlich to represent the neutralizing power of antitoxin in the presence of toxin, toxone, etc. (05 Mar 2000) |
| erythrogenic toxin | <protein> Toxin produced by strains of Streptococcus pyogenes responsible for scarlet fever. Three antigenic variants of the toxin are known. It is a small protein that is complexed with hyaluronic acid and can intensify the effects of other toxins such as endotoxin and streptolysin O. (18 Nov 1997) |
| extracellular toxin | <protein> Toxin released from gram-positive and gram-negative bacteria as opposed to endotoxins that form part of the cell wall. Examples are cholera, pertussis and diphtheria toxins. Usually specific and highly toxic. (18 Nov 1997) |