RECOMBINAGENIC ACTIVITY OF INTEGERRIMINE A PYRROLIZIDINE ALKALOID FROM SENECIO-BRASILIENSIS, IN SOMATIC-CELLS OF DROSOPHILA-MELANOGASTER

Integerrimine (ITR), a pyrrolizidine alkaloid From Senecio brasiliensi s, was tested For genotoxicity using the wing somatic mutation and rec ombination test (SMART) in Drosophila melanogaster. The compound was a dministered by chronic feeding (48 hours) of 3-day-old larvae. Two dif ferent crosses involving the markers Flare (flr) and multiple wing hai rs (mwh) were used, that is, the standard (ST) cross and the high bioa ctivation (HE) cross, which has a high cytochrome P450-dependent bioac tivation capacity. In both crosses, the wings of two types of progeny were analyzed, that is, inversion-free marker heterozygotes and balanc er heterozygotes carrying multiple inversions. ITR was found to be equ ally potent in inducing spots In a dose-related manner in the marker h eterozygotes of both crosses. This indicates that the bioactivation ca pacity present in larvae of the ST cross is sufficient to reveal the g enotoxic activity of ITR. In the balancer heterozygotes of both crosse s, where all recombinational events ore eliminated due to the inversio ns, the Frequencies of induced spots were considerably reduced which d ocuments the recombinogenic activity of ITR. Linear regression analysi s of the dose response relationships For both genotypes shows that 85% to 90% of the wing spots are due to mitotic recombination. (C) 1997 W iley-liss, Inc.