Cell walls toxins

Other toxins that show low lethal toxicity to laboratory test animals include lipopolysaccharide endotoxin produced as part of the cell wall by all cyanobacteria 11) and certain toxins of some cyanobacteria suspected of causing contact irritation in recreational water supplies 4,12 Carmichael and Codd, unpublished results). 

Group II includes bacteria that produce toxins responsible for the course of disease during gastrointestinal invasion. Disease symptoms are the result of cell destruction caused by extracellular toxins and by elements present in the cell wall, e.g., fimbriae. Such toxins are not... 

Endotoxin. A heat-stable bacterial toxin not freely liberated into the surrounding medium. Endotoxins are released only when the integrity of the cell wall is disturbed, are less potent than most exotoxins, are less specific, and do not form toxoids. When injected in large quantities, endotoxins produce hemorrhagic shock and severe diarrhea. Smaller amounts cause fever, altered resistance to bacterial infections, leukopenia followed by leukocytosis, and numerous other biological effects. 

Recombinant vaccines Vaccines that can deliver and penetrate intestinal wall via M cells Tetanus toxin, Salmonella strains, vaccinia virus vector... 

The role of zinc in the enzymes listed in Table 12 is very often that of a strong Lewis acid, in which substrates are coordinated, polarized and hence activated. In other cases, zinc may play a regulatory, structural or template role. Zinc may also have a structural function in other biological molecules, for example in the unwinding and subsequent rewinding of the double-stranded polymers involved in replication and transcriptional processes. There is also evidence for a role for zinc in the stabilization of membranes and cell walls.463 The high concentrations of zinc in certain snake venoms reflect the presence in the venom of proteolytic enzymes and hemorrhagic toxins that all require zinc for activity.464... 

Blue-green algae (cyanobacteria) can occur in surface water bodies used for water supply Some species of cyanobacteria contain toxins of concern to human health (e.g. microcystins), and these can be released when algal cell walls are ruptured, There is a wide range of potential toxins and it appears that not all of the possible toxins have been identified. 

Primary metabolites are often released into the surrounding medium, whereas secondary metabohtes tend to remain inside the cell and can be recovered only after lyses of the cell walls. Some metabolites are toxic therefore any fermentation must be monitored for toxins. Two types are distinguished exotoxins are released into the fermentation broth, endotoxins remain inside the cell and are sometimes difficult to detect (Fig. 9.3). 

Toxin derived from the seeds of the Rosary pea or Jequirity bean (Abrus pecatorius). Powdered abrin is yellowish-white it is soluble in water and stable. Two glycoprotein chains acidic chain (30000D) - inhibits protein synthesis neutral chain (35 000D) - binds to cell wall and facilitates entry. Effects similar to ricin qv, but it is more toxic. 

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