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 ?
DNA fragmentation and cytolysis in U937 cells treated with diphtheria toxin or other inhibitors of protein synthesis.
Next, Murphy plans to construct another hybrid protein, a diphtheria toxin that binds to receptors for interleukin-2 on white blood cell membranes.
ONTAK is contraindicated for use in patients with a known sensitivity to denileukin diftitox or any of its components: diphtheria toxin, IL-2, or excipients.
ulcerans produce potent diphtheria toxin and may cause severe symptoms similar to those caused by C.
Its BC-819 clinical stage product candidate is a double stranded DNA plasmid construct that incorporates the gene for diphtheria toxin (DTA) under the regulation of the promoter sequence for H19 gene.
It is based on the transferrin-mediated delivery of a modified diphtheria toxin, which is capable of selectively killing cancer cells.
It has been suggested that nontoxigenic strains could become toxigenic by acquiring the tox gene, assuming that the chromosomal diphtheria toxin repressor gene (dtxR) is functional (14-16).
Protection against disease is due to the development of neutralizing antibodies to diphtheria toxin.
By genetically engineering the normal diphtheria toxin gene, we created a toxin that would be produced only in prostate cells," explained Dr.
Traditional Agents associated with biological warfare biocrimes and agents bioterrorism Pathogens Bacillus anthracis(b) Ascaris suum Brucella suis Bacillus anthracis(b) Coxiella burnetii(b) Coxiella burnetii(b) Francisella tularensis Giardia lamblia Smallpox HIV Viral encephalitides Rickettsia prowazekii Viral hemorrhagic (typhus) fevers(b) Yersinia pestis(b) Salmonella Typhimurium Salmonella typhi Shigella species Schistosoma species Vibrio cholerae Viral hemorrhagic fevers (Ebola)(b) Yellow fever virus Yersinia enterocolitica Yersinia pestis(b) Toxins Botulinum(b) Botulinum(b) Ricin(b) Cholera endotoxin Staphylococcal Diphtheria toxin enterotoxin B Nicotine Ricin(b) Snake toxin Tetrodotoxin Anti-crop Rice blast agents Rye stern mst Wheat stem mst
The leading drug, BC-819, used in these clinical trials is a double stranded DNA plasmid construct that incorporates the gene for diphtheria toxin (DTA) under the regulation of the promoter sequence for H19 gene.
Since diphtheria toxin was isolated by Roux and Yersin in 1888 (1), microbial toxins have been recognized as the primary virulence factor(s) for a variety of pathogenic bacteria.

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