Tryptohan photoproduct as a genetic probe : effects on bacteria

Recombinationless (rec) mutants of bacteria are sensitive to visible and near-ultraviolet wavelengths of light. In addition, these mutants are sensitive to a tryptophan photoproduct that results from irradiation of this amino acid by 280-365 nm wavelengths. The physical and biological damages are different from those produced by 254 nm UV. Both the longer wavelengths and the tryptophan photoproduct are mutagenic and influence the genetic recombinational process in bacteria. Since the natural environment includes an abundance of both free tryptophan and sunlight, the relevance of the effect of these agents is provocative.A. EISENSTARK, Division of Biological Sciences, University of Missouri-Columbia Columbia, Missouri