Mary Jacewicz

[22] Shiga toxin: Production and purification

Publisher Summary This chapter describes the production and purification of Shiga Toxin. Shiga toxin is among the old known protein toxins derived from gram-negative bacilli. It was first clearly described in the prototypic species, Shigella dysenteriae 1 (or Shigas Bacillus ), in 1903. Because parenteral injection of Shiga toxin into susceptible animals resulted in a delayed limb paralysis followed by death, it was called Shiga neurotoxin (or, simply Shiga toxin). With the exception of tissue culture methods, other bioassays for Shiga toxin are time consuming, subjected to considerable day-to-day variability, and expensive because of the costs of purchasing and maintaining animals. In addition, certain types of E. coli capable of causing intestinal disease, including classical enteropathogenic E. coli (EPEC) and the newly described agents of hemorrhagic colitis, E. coli 0157: H7 and 026 : H 11 produce a cytotoxin either identical to or highly related to Shiga toxin.

[33] Shiga toxin as inhibitor of protein synthesis

Publisher Summary This chapter describes the Shiga toxin as inhibitor of protein synthesis. Shiga toxin, a protein produced by all strains of Shigella dysenteriae , is a potent inhibitor of eukaryotic protein synthesis. The molecule is composed of two distinct polypeptide subunits, both of which play an essential role in mediating inhibition of cellular protein synthesis caused by the addition of toxin to intact mammalian cells. Two bacterial toxins, pseudomonas exotoxin A and diphtheria toxin are known to inhibit protein synthesis by catalyzing the transfer of the adenosine diphosphate moiety from nicotinamide adenine dinucleotide (NAD) to the protein synthesis elongation factor (EF-2). Shiga toxin is a lethal cytotoxin to a limited number of tissue culture cell lines. Susceptible cells are primate epithelial cells, including the human cervical carcinoma-derived HeLa line, and the African Green monkey kidney Vero cell line. Many epithelial and nonepithelial cell lines are resistant to Shiga toxin. The toxin A subunit is responsible for the inhibition of protein synthesis caused by the intact toxin.