Threat assessment of mycotoxins as weapons: molecular mechanisms of acute toxicity.

Mycotoxins are impractical as tactical weapons, butthey can be used by small poor terrorist organizations to poison food and water sources or can be released in crowded, confined areas. Crude concentrated or dried extracts of readily grown fungal cultures can be used as weapons. The production of fungal weapons does not require elaborate facilities for the growth of fungi, sophisticated equipment for the purification of the toxins, or highly trained personnel. Aflatoxin B1, fumonisin B1, ochratoxin A, and the trichothecenes T-2 toxin and deoxynivalenol could be weaponized for bioterrorism. Knowledge of the symptoms of intoxication and the biochemical mechanisms of action of mycotoxins is necessary for the rapid identification of the toxins, the development of prophylactic antidotes, and the design of effective treatments of affected persons. All of these mycotoxins except deoxynivalenol are carcinogens (Stark, A. A., Annu. Rev. Microbiol. 34:235-262, 1980; Stark, A. A., p. 435-445, in P. S. Steyn and R. Vleggaar, ed., Mycotoxins and phycotoxins, 1986; Stark, A. A., p. 47-60, in C. L. Wilson and S. Droby, ed., Microbial food contamination, 2000; Stark, A. A., and N. Paster, p. 60-64, in M. L. Wahlqvist, A. S. Truswell, R. Smith, and P. L. Nestel, ed., Nutrition in a sustainable environment, 1994). Because immediate and widespread death, illness, or panic is the goal of bioterrorists, the mechanisms by which mycotoxins exert acute toxicity are the focus of this article.

A spectrophotometric assay of gamma-glutamylcysteine synthetase and glutathione synthetase in crude extracts from tissues and cultured mammalian cells.

An assay of gamma-glutamylcysteine synthetase (gamma-GCS) and glutathione synthetase (GS) in crude extracts of cultured cells and tissues is described. It represents a novel combination of known methods, and is based on the formation of glutathione (GSH) from cysteine, glutamate and glycine in the presence of rat kidney GS for the assay of gamma-GCS, or from gamma-glutamylcysteine and glycine for the assay of GS. GSH is then quantified by the Tietze recycling method. Assay mixtures contain the gamma-glutamyl transpeptidase (GGT) inhibitor acivicin in order to prevent the degradation of gamma-glutamylcysteine and of the accumulating GSH, and dithiothreitol in order to prevent the oxidation of cysteine and gamma-glutamylcysteine. gamma-GCS and GS levels determined by this method are comparable to those determined by others. The method is suitable for the rapid determination of gamma-GCS GS in GGT-containing tissues and for the studies of induction of gamma-GCS and GS in tissue cultures.