Enterotoxin
Encyclopedia
An enterotoxin is a protein
toxin
released by a microorganism
in the intestine
.
Enterotoxins are chromosomally encoded exotoxin
s that are produced and secreted from several bacterial organisms. They are often heat-stable, and are of low molecular weight and water-soluble. Enterotoxins are frequently cytotoxic and kill cells by altering the apical membrane permeability
of the mucosal (epithelial) cells of the intestinal wall. They are mostly pore-forming toxins (mostly chloride pores), secreted by bacteria, that assemble to form pores in cell membranes. This causes the cells to die.
The action of enterotoxins leads to increased chloride ion permeability of the apical membrane of intestinal mucosal cells. These membrane pores are activated either by increased cAMP or by increased calcium ion concentration intracellularly. The pore formation has a direct effect on the osmolarity of the luminal contents of the intestines. Increased chloride permeability leads to leakage into the lumen followed by sodium and water movement. This leads to a secretory diarrhea within a few hours of ingesting enterotoxin. Several microbial organisms contain the necessary enterotoxin to create such an effect, such as Staphylococcus aureus and E. coli.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
released by a microorganism
Microorganism
A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...
in the intestine
Intestine
In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...
.
Enterotoxins are chromosomally encoded exotoxin
Exotoxin
An exotoxin is a toxin excreted by a microorganism, like bacteria, fungi, algae, and protozoa. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism. They are highly potent and can cause major damage to the host...
s that are produced and secreted from several bacterial organisms. They are often heat-stable, and are of low molecular weight and water-soluble. Enterotoxins are frequently cytotoxic and kill cells by altering the apical membrane permeability
Semipermeable membrane
A semipermeable membrane, also termed a selectively permeable membrane, a partially permeable membrane or a differentially permeable membrane, is a membrane that will allow certain molecules or ions to pass through it by diffusion and occasionally specialized "facilitated diffusion".The rate of...
of the mucosal (epithelial) cells of the intestinal wall. They are mostly pore-forming toxins (mostly chloride pores), secreted by bacteria, that assemble to form pores in cell membranes. This causes the cells to die.
Clinical significance
Has a particularly marked effect upon the gastrointestinal tract, causing vomiting, diarrhoea, and abdominal pain.The action of enterotoxins leads to increased chloride ion permeability of the apical membrane of intestinal mucosal cells. These membrane pores are activated either by increased cAMP or by increased calcium ion concentration intracellularly. The pore formation has a direct effect on the osmolarity of the luminal contents of the intestines. Increased chloride permeability leads to leakage into the lumen followed by sodium and water movement. This leads to a secretory diarrhea within a few hours of ingesting enterotoxin. Several microbial organisms contain the necessary enterotoxin to create such an effect, such as Staphylococcus aureus and E. coli.
Bacterial
- Clostridium difficileClostridium difficileClostridium difficile , also known as "CDF/cdf", or "C...
- Escherichia coli O157:H7Escherichia coli O157:H7Escherichia coli O157:H7 is an enterohemorrhagic strain of the bacterium Escherichia coli and a cause of foodborne illness. Infection often leads to hemorrhagic diarrhea, and occasionally to kidney failure, especially in young children and elderly persons...
- Clostridium perfringensClostridium perfringensClostridium perfringens is a Gram-positive, rod-shaped, anaerobic, spore-forming bacterium of the genus Clostridium. C. perfringens is ever present in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates,...
(Clostridium perfringens enterotoxinClostridium perfringens enterotoxinClostridium enterotoxins are toxins produced by Clostridium species.Clostridial species are one of the major causes of food poisoning/gastro-intestinal illnesses. They are anaerobic, gram-positive, spore-forming rods that occur naturally in the soil...
) - Vibrio choleraeVibrio choleraeVibrio cholerae is a Gram-negative, comma-shaped bacterium. Some strains of V. cholerae cause the disease cholera. V. cholerae is facultatively anaerobic and has a flagella at one cell pole. V...
(Cholera toxinCholera toxinCholera toxin is a protein complex secreted by the bacterium Vibrio cholerae. CTX is responsible for the massive, watery diarrhea characteristic of cholera infection.- Structure :...
) - Staphylococcus aureusStaphylococcus aureusStaphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. It is frequently found as part of the normal skin flora on the skin and nasal passages. It is estimated that 20% of the human population are long-term carriers of S. aureus. S. aureus is the most common species of...
(Staphylococcal Enterotoxin BStaphylococcal Enterotoxin BStaphylococcal enterotoxin B is an enterotoxin produced by the bacterium Staphylococcus aureus. It is a common cause of food poisoning, with severe diarrhea, nausea and intestinal cramping often starting within a few hours of ingestion.. Being quite stable, the toxin may remain active even after...
) - Yersinia enterocoliticaYersinia enterocoliticaYersinia enterocolitica is a species of gram-negative coccobacillus-shaped bacterium, belonging to the family Enterobacteriaceae. Yersinia enterocolitica infection causes the disease yersiniosis, which is a zoonotic disease occurring in humans as well as a wide array of animals such as cattle,...
- Shigella dysenteriaeShigella dysenteriaeShigella dysenteriae is a species of the rod-shaped bacterial genus Shigella. Shigella can cause shigellosis . Shigellae are Gram-negative, non-spore-forming, facultatively anaerobic, non-motile bacteria.S...
(Shiga toxinShiga toxinShiga toxins are a family of related toxins with two major groups, Stx1 and Stx2, whose genes are considered to be part of the genome of lambdoid prophages. The toxins are named for Kiyoshi Shiga, who first described the bacterial origin of dysentery caused by Shigella dysenteriae. The most common...
)