Shigella Endotoxins

Shigella endotoxin, too, caused the regression of some established s.c. or intrade rmal tumors in mice, when administered systemically or directly into the tumor . 

Shigella Colonization and invasion of epithelial cells in large intestine Replication in cytoplasm Aeromonas sp. Endotoxins, exotoxins, invasins, extracellular enzymes, adhesions, siderophores Clostridium Neurotoxins botulinum... 

They are generally toxic to most body tissues, and are less potent than exotoxins. They are typified by the following, Escherichia coli (wound infection and septicaemia), Klebsiella pneumoniae (urogenital tract infections). Shigella dysenterlae (dysentery). Salmonella typhosa (typhoid fever), Pasteurella pestis (bubonic plague) and Pseudomonas aeruginosa (wound infections and septicaemia). Not all of these endotoxins are fully characterized, and some toxic mechanisms are obscure. 

Endotoxins. Name for bacterial toxins which, in contrast to the exotoxins, are not secreted by living bacteria but are released from the cells by autolysis (e.g. in the intestines). In the case of classic E. they consist of the thermostable lipopolysaccharide (LPS-) fraction of the cell membrane anchored on the outer membranes of Gram-negative bacteria. The LPS consists of lipid A, the chain polysaccharide, and the O-specific chain lipid A is responsible for the toxic action of LPS. E. are found in all Enterobacteriaceae, e.g.. Salmonella (typhus), Shigella (dysentery), and many other Gramnegative pathogens. In the host organism E. stimulate mediators (cytokines) of the immune system. One of... 

A poison (toxin) that remains inside the microorganism which produced it. The toxicity is noted only when the bacterial cells are ruptured by mechanical or chemical means. Escherichia coll, Salmonella typhi and Shigella dysenteriae bacteria are known to form endotoxins. 

Hence lipid A is the biologically active component of endotoxin which is common both to the lipopolysaccharide of S-forms and the glycolipids of R-forms of the great majority of enterobacteria (Salmonella, Escherichia, Citrobacter, Shigella, Serratia). 

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