diphtheria toxin


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toxin

 [tok´sin]
a poison, especially a protein or conjugated protein produced by certain animals, higher plants, and pathogenic bacteria. Bacterial toxins characteristically do not cause symptoms until after a period of incubation while the microbes multiply, or (as happens with botulism) the preformed toxin reaches and affects the tissue. Usually only a few toxin-producing agents are introduced into the body, and it is not until there are enough of them to overwhelm the leukocytes and other types of antibodies that symptoms occur. In some cases of food poisoning, symptoms are almost immediate because the toxin is taken directly with the food. Toxins can cause antitoxins to form in the body, thus providing a means for establishing immunity to certain diseases.
bacterial t's toxins produced by bacteria, including exotoxins, endotoxins, enterotoxins, neurotoxins, and toxic enzymes. See also toxin.
botulinal toxin (botulinum toxin) (botulinus toxin) one of seven type-specific, immunologically differentiable exotoxins (types A to G) produced by Clostridium botulinum,neurotoxins usually found in imperfectly canned or preserved foods. They cause botulism by preventing release of acetylcholine by the cholinergic fibers. Type A is one of the most powerful poisons known; it is also used therapeutically by injection to inhibit muscular spasm in the treatment of dystonic disorders such as blepharospasm and strabismus, to treat wrinkles of the upper face, and to reduce anal sphincter pressure to promote healing of chronic anal fissure. Type B is injected in treatment of cervical dystonia. Called also botulin.
cholera toxin an exotoxin produced by Vibrio cholerae; a protein enterotoxin that binds to the membrane of enteric cells and stimulates the adenylate cyclase system, causing the hypersecretion of chloride and bicarbonate ions, resulting in increased fluid secretion and the severe diarrhea characteristic of cholera.
clostridial toxin one elaborated by species of Clostridium, including those causing botulism (botulinus toxin), gas gangrene (gas gangrene toxin), and tetanus (tetanus toxin). In addition, C. difficile produces an exotoxin causing severe intestinal necrosis and C. perfringens produces exotoxins causing gas gangrene, intestinal necrosis, hemolysis, cardiotoxicity, and deoxyribonuclease and hyaluronidase activity, as well as an enterotoxin causing food poisoning.
Dick toxin erythrogenic toxin.
diphtheria toxin a protein exotoxin produced by Corynebacterium diphtheriae that is primarily responsible for the pathogenesis of diphtheria and related infections; it is an enzyme that activates transferase II of the mammalian protein synthesizing system.
diphtheria toxin for Schick test a sterile solution of the diluted, standardized toxic products of Corynebacterium diphtheriae; used as a dermal reactivity indicator in the schick test of immunity to diphtheria.
dysentery toxin any of various exotoxins produced by species of Shigella; the one formed by S. dysenteriae serotype 1 is a potent neurotoxin with hemorrhagic and paralytic properties.
erythrogenic toxin a bacterial toxin from certain strains of Streptococcus pyogenes that produces an erythematous reaction when injected intradermally and is responsible for the rash in scarlet fever.
extracellular toxin exotoxin.
gas gangrene toxin an exotoxin that causes gas gangrene; there are at least 10 types produced by Clostridium perfringens and others produced by C. noriyi and C. septicum.
streptococcal toxin a mixture of exotoxins formed by Streptococcus pyogenes.
tetanus toxin the potent exotoxin produced by Clostridium tetani, consisting of two components, one a neurotoxin (tetanospasmin) and the other a hemolysin (tetanolysin).

Cor·y·ne·bac·te·ri·um diph·the·'ri·ae

a bacterial species that causes diphtheria and produces a powerful exotoxin causing degeneration of various tissues, notably myocardium, in humans and experimental animals, and catalyzing the ADP-ribosylation of elongation factor II; virulent strains of this organism are lysogenic; it is commonly found in membranes in the pharynx, larynx, trachea, and nose in cases of diphtheria; it is also found in apparently healthy pharynx and nose in carriers, and occasionally in the conjunctiva and in superficial wounds; it occasionally infects the nasal passages and wounds of horses; it is the type species of the genus Corynebacterium.

diphtheria toxin

Etymology: Gk, diphtheria + toxikon, poison
the filtrate of a broth culture used to prepare an intradermal injectable form of toxin for Schick tests. A positive test result is characterized by an inflammatory reaction at the point of injection, whereas circulating antibodies in the blood cause a negative test result, indicating immunity.

diphtheria toxin

Infectious disease A 62 kD protein responsible for C diphtheriae's cardiotoxic and neurotoxic effects, and mucosal damage. See Corynebacterium diphtheriae, Diphtheria.
References in periodicals archive ?
Inhibition of membrane translocation of diphtheria toxin A-fragment by internal disulfide bridges.
Development of a direct PCR assay for detection of the diphtheria toxin gene.
Booster vaccination of adults induces up to 10 IU/mL of IgG against diphtheria toxin in plasma 4 weeks after vaccination (8-13) (Table).
Other Corynebacterium species may rarely produce diphtheria toxin but still cause a diphtheria-like disease in humans that is preventable through vaccination (4).
Experimenting with a birth-control vaccine that uses the tetanus rather than diphtheria toxin to stimulate antibodies is G.
Detection of differences in the nucleotide and amino acid sequences of diphtheria toxin from Corynebacterium diphtheriae and Corynebacterium ulcerans causing extrapharyngeal infections.
Murphy and his colleagues have produced a hybrid protein that is a modified diphtheria toxin.
The tox gene, encoding diphtheria toxin, was present, which verified the diphtheria-like disease in the patient.
Strains of this group carrying lysogenic [beta]-corynephages might produce the tox-encoded diphtheria toxin (DT) (2).
The presence of toxin genes for diphtheria toxin (tox) (7) and phospholipase D (pld) (3) were evaluated by PCR.
Since introduction of vaccine against the diphtheria toxin in the 1940s, infections caused by toxigenic corynebacteria have been well controlled in industrialized countries that have high coverage rates of childhood vaccination with 3 doses of diphtheria-tetanus-pertussis vaccine (1).
pseudotuberculosis) can potentially produce diphtheria toxin.

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