Corynebacterium diptheriae

Examples are diphtheria and tetanus vaccines. Diphtheria vaccine is produced by formaldehyde treatment of the toxin secreted by Corynebacterium diptheriae. Similarly, tetanus vaccine is obtained from toxins of cultured Clostridium tetani that has been treated with formaldehyde. 

Many toxins interfere with intracellular functions. The best-characterized of these are diphtheria toxin and cholera toxin, produced by the bacteria Corynebacterium diptheriae and Vibrio cholerae, respectively. Both of these toxins contain two subunits, called A and B. The A subunit is responsible for the toxic effect, whereas the B subunit binds to the target cell. Once diphtheria toxin has entered the target cell, the A and B subunits split apart. The A subunit, which is an enzyme, catalyzes a reaction that prevents protein synthesis. The cell dies because it cannot synthesize proteins. The host organisms dies because cardiac, kidney, and nervous tissue are destroyed. 

Table 13.1 shows a list of some bacteria with the number of CYPs associated with their genomes to date. Most striking are the number and diversity seen among actinomycetes such as strep-tomycetes and mycobacteria, although some actinomycetes, such as Corynebacterium diptheriae, have no CYPs. Much of the CYP diversity is likely to be due to their role in secondary metabolism, as is true in the filamentous gram-negative... 

Jagielski, M., 1969, Corynebacterium diptheriae. 1. Purification and physical properties, Med. Dosiv. Mikrobiol. 21 137-150. 

A-B Toxins are bacterial toxins composed of two peptide chains one (B) that binds to the invaded cell surface, and the other (A) containing the toxin which is then taken-up into the cell. Some examples of exotoxins secreted by the bacteria into the surrounding medium and highly toxic to certain tissues are pathogens causing botuiism (Clostridium botulinum), tetanus (Clostridium tetani) and diptheria (Corynebacterium diphtheria. An example of an A-B endotoxin is Vibrio cholerae. Botulinum toxin and tetanus toxin have their main toxic actions on neuronal tissues, so are described at NEUROTOXINS. 

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