ANALYSIS OF THE 6 ADDITIONAL CHEMICALS FOR INVITRO ASSAYS OF THE EUROPEAN-ECONOMIC-COMMUNITIES EEC ANEUPLOIDY PROGRAM USING SACCHAROMYCES-CEREVISIAE D61.M AND THE INVITRO PORCINE BRAIN TUBULIN ASSEMBLY ASSAY

We tested six additional chemicals (acetaldehyde, benomyl, diethylstilboestrol, diethylstilboestrol dipropionate, griseofulvin, and mercaptoethanol) for in vitro systems of the coordinated programme to study aneuploidy induction sponsored by the Commission of the European Communities in two in vitro test systems. Using Saccharomyces cerevisice D61.M (mitotic chromosomal malsegregation assay), benomyl showed a dose-dependent increase in the frequency of chromosomal malsegregation with a lowest effective dose tested (LEDT) of 30 mug/ml (0.1 mM). Diethylstilboestrol (DES) showed solvent-dependent effects. DES dissolved in ethanol induced an increase in chromosomal malsegregation as well as in the frequency of total resistant colonies (mutations and recombinations) with a LEDT arround 13 mug/ml (0.048 mM). Using dimethylsulfoxide as the solvent, no increases were observed with DES up to 333 mug/ml (1.24 mM). Acetaldehyde induced an increase in chromosomal malsegregation with the cold treatment protocol (LEDT: 1.25 mul/ml (21 mM) and 0.75 mul/ml (13 mM), respectively) but no increase with the overnight protocol (highest dose tested (HDT): 1.75 mul/ml; 30 mM). Concerning the frequency of total cycloheximide-resistant colonies (mutations and recombinations) increases were obtained with both protocols. The other three compounds were negative when tested up to toxic doses (survival below 10%), up to the maximum solubility in the solvent used or up to heavy precipitation in the incubation mix. The HDT were 333 mug/ml (0.88 mM) for diethylstilboestrol dipropionate, 1,600 mug/ml (4.5 mM) for griseofulvin and 0.5 mul/ml (7 mM) for mercaptoethanol. Concerning effects on porcine brain tubulin assembly in vitro, diethylstilboestrol and griseofulvin inhibited the assembly process. The IC30% (30% inhibition concentration) values were 12.5 muM and 100 muM for DES and griseofulvin, respectively. Mercaptoethanol showed no effects up to 50 mM.