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Enterotoxins can be formed by the bacterial pathogens Staphylococcus aureus and Bacillus cereus and can cause Staphylococcal Food Poisoning and Bacillus cereus diarrheal disease, respectively. Staphylococcal enterotoxins and streptococcal exotoxins constitute a family of biologically and structurally related pyrogenic superantigens .
Clostridium enterotoxins are toxins produced by Clostridium species. [2] Clostridial species are one of the major causes of food poisoning / gastrointestinal illnesses . They are anaerobic , [ 1 ] gram-positive, spore-forming rods that occur naturally in the soil. [ 3 ]
Heat-stable enterotoxins (STs) are secretory peptides produced by some bacterial strains, such as enterotoxigenic Escherichia coli [2] which are in general toxic to animals. These peptides keep their 3D structure and remain active at temperatures as high as 100 °C.
Enterotoxins are chromosomally encoded exotoxins that are produced and secreted from several bacterial organisms. It is a heat stable toxin and is resistant to digestive protease . [ 5 ] [ 6 ] It is the ingestion of the toxin that causes the inflammation and swelling of the intestine.
[3] [4] [5] A number of pathogenic isolates are termed ETEC, but the main hallmarks of this type of bacterium are expression of one or more enterotoxins and presence of fimbriae used for attachment to host intestinal cells. The bacterium was identified by the Bradley Sack lab in Kolkata in 1968.
This group comprises 25 staphylococcal enterotoxins (SEs) which have been identified to date and named alphabetically (SEA–SEZ), [62] including enterotoxin type B as well as the toxic shock syndrome toxin TSST-1 which causes TSS associated with tampon use.
Examples of virulence factors for Staphylococcus aureus are hyaluronidase, protease, coagulase, lipases, deoxyribonucleases and enterotoxins. Examples for Streptococcus pyogenes are M protein , lipoteichoic acid , hyaluronic acid capsule, destructive enzymes (including streptokinase , streptodornase , and hyaluronidase ), and exotoxins ...
These toxins consist of an AB5 multimer structure, in which a pentamer of B chains has a membrane-binding function and an A chain is needed for enzymatic activity. [3] The B subunits are arranged as a doughnut-shaped pentamer, each subunit participating in ~30 hydrogen bonds and 6 salt bridges with its two neighbours.