GENOTOXIC ACTIVITIES IN-VIVO OF COBALTOUS CHLORIDE AND OTHER METAL CHLORIDES AS ASSAYED IN THE DROSOPHILA WING SPOT-TEST

A series of metal chlorides were subjected to the wing spot test of Dr osophila melanogaster. In the test, larvae trans-heterozygous for the wing-hair mutations mwh and flr were orally treated at the third insta r stage with a test compound and the wings were inspected at the adult stage for spots expressing phenotypes of the markers. CoCl2, MnCl2, M oCl3, NiCl2 and ZnCl2 were clearly effective in inducing spots with on e or two mutant hairs (small spots). CoCl2 was clearly effective in in ducing spots with three or more mutant hairs (large spots) as well. Cr Cl3, FeCl2 and FeCl3 were negative under the conditions used. Based on estimated frequencies of small spots induced at the LD(50), the genot oxic effectiveness of the positive metal salts were ranked in a sequen ce of CoCl2 > ZnCl2 > MoCl3 > (MnCl2, NiCl2). Since CoCl2 did not indu ce large spots in the wings of the mwh / TM3 flies with a suppressed a bility of mitotic crossing-over, the large spots induced by this compo und in the mwh/flr system were ascertained as mutant clones due to mit otic crossing-overs.