Cytogenetic hazards from agricultural chemicals. I. A preliminary study on the responses of root meristems to exotoxin from Bacillus thuringiensis a constituent of a microbial insecticide, thuricide.
It reported for the first time that the exotoxin, thuringiensin A, from Bacillus thuringiensis, a component of the insecticide thuricide, inhibits spindle and cytokinesis and induces micronuclei, chromocentric nuclei and minor deviations in spindle activity. The binucleate cells also undergo mitosis yielding biprophases and bimetaphases. Spindle seems to have been inhibited even in bimetaphase. Microtubular systems and chromosomes are implicated as the primary targets. Most effects resemble those of caffeine, colchicine, aminopyrin, chloral hydrate and vinblastine to different extents, and are therefore suggestive of the anti-neoplastic and mutagenic potentialties of the exotoxin. The extensive use of thuricide on crop plants, in view of its mutagenic potential, may be hazardous. The results also suggest that the exotoxin may be used as a pre-treating agent in chromosome analysis and as a candidate-tagging tool for synchronization and cell cycle analysis, besides its probable utility in studies on cancer cells.