The Genetic Basis of Toxin Production in Clostridium botulinum and Clostridium tetani

Publisher Summary This chapter provides an overview of the genetic basis of toxin production in Clostridium botulinum and Clostridium tetani . Classified as either tetanus neurotoxin (TeNT) or botulinum neurotoxin (BoNT), they are synthesized as single polypeptide chains that are subsequently cleaved by bacterial proteases to produce di-chain toxins, each comprising a light chain and a heavy chain linked by a single disulphide bridge. The molecular analysis of the toxin structural genes has played a significant part. Genetic analysis has also revealed other information on toxin production, gene transfer, diagnosis, and prevention. Representative genes of all of the clostridial neurotoxins, from the various serotypes and physiological groups, have been isolated and sequenced. Several groups have been involved in the development of oligonucleotide primers for the detection of neurotoxin genes using polymerase chain reaction based methods. Dissemination of the neurotoxin genes between the physiological groups implies that the genes are, or have been at one time, encoded on mobile genetic elements such as transposons, plasmids and bacteriophage genomes.