Somatic mutation induced by heliotrine in Drosophila.

Abstract

The pyrrolizidine alkaloid heliotrine has been shown to be a powerful mutagen in Drosophila. This report has evaluated the teratogenicity of heliotrine in this organism. The alkaloid was fed to larvae and its teratogenic effects measured in various developmental stages of the insect. The pupal stage is predominantly affected. The main consequences of treatment were failed eclosions at higher alkaloid concentrations (10(-4) M), while lower concentrations (10(-5) M) permitted the eclosion of adults, but these showed abdominal abnormalities ranging from severe distortions to reduced numbers of tergite bristles. mei-9 strains of Drosophila were more sensitive to the production of somatic chromosomal changes as well as the teratogenic effects of the alkaloid. These strains also showed reduced numbers of cells in histoblast nests of 6-hour-old prepupae. It is suggested that reduced numbers of histoblast cells in prepupae may be a consequence of genetic damage and this in turn leads to the abdominal distortions and reduced bristle numbers observed.