Anthrax

Bacillus anthracis was shown to be the etiological agent of anthrax by R. K och and L. Pasteur at the end of the nineteenth century. The concepts on wh ich medical microbiology are based arose from their work on this bacterium. The link between plasmids and major virulence factors of B. anthracis was not discovered until the 1980s. The three toxin components are organized in two A-B type toxins, and the bacilli are covered by an antiphagocytic poly glutamic capsule. Structure-function analysis of the toxins indicated that the common B-domain binds to a ubiquitous cell receptor and forms a heptame r after proteolytic activation. One enzyme moiety is an adenylate cyclase a nd the other is a Zn2+ metalloprotease, which is able to cleave MAPKKs. The capsule covers an S-layer sequentially composed of two distinct proteins. Knowledge of the toxins facilitates the design of safer veterinary vaccines . Spore-structure analysis could contribute to the improvement of human non living vaccines. The phylogeny of B. anthracis within the Bacillus cereus g roup is also reviewed.