Lack of effect of acute acetaldehyde treatment on X chromosome segregation in Drosophila melanogaster females

Chromosome malsegregation induced by the rodent carcinogens acetamide, pyridine and diethanolamine in Drosophila melanogaster females

The effect of the rodent carcinogens acetamide (AC), pyridine (PY) and diethanolamine (DEA) on meiotic chromosome segregation was assessed in 4-day-old Drosophila melanogaster females. After oral treatment with 0.05, 0.1, 0.2 and 0.3% PY; 0.5, 1, 1.5, 2 and 4% AC; or 5, 10, 20, 40 and 80% DEA, the females were mated to 7-day-old males and three 24h broods were obtained to sample cells exposed mainly as mature oocytes (brood I), and nearly mature oocytes (brood II) with an increasing proportion of early oocytes (brood III). Viability was not affected at the two (PY) or three (AC, DEA) lowest concentrations, decreasing thereafter. PY increased the frequency of nondisjunction exclusively in brood II suggesting its interaction with specific targets. AC and DEA (the most active of the three) induced similar frequencies of nondisjunction in all broods suggesting unspecific cell division perturbations probably due to toxicity. No clear dose effect relationships were observed.

Effect of disulfiram on the genotoxic potential of acetaldehyde in mouse spermatogonial cells

The initial purpose of the study was to determine the potential of acetaldehyde (Ace) to increase the rate of sister-chromatid exchanges (SCEs) in mouse spermatogonia. We tested four doses of Ace (from 0.4 to 400.0 mg/kg), including a negative and a positive control group (distilled water and cyclophosphamide, respectively). The results showed that all tested doses were SCE inducers. The highest tested dose increased the control level more than three times. Also, the cumulative frequencies of SCEs per cell were higher in the Ace-treated animals than in the control cells. Ace is transformed into acetate through the enzyme aldehyde dehydrogenase, a process that may be blocked by disulfiram (Dis) generating the accumulation of Ace. The second purpose of the study was to determine if the administration of Dis (150 mg/kg) could increase the SCE rate produced by non-genotoxic doses of Ace. (0.004 and 0.04 mg/kg). The animals treated with the two doses of Ace alone showed no increase in the frequency of SCEs; also, Dis by itself was not an SCE inducer. However, the groups of animals previously treated with Dis showed an increase of 31 and 60% with respect to the values obtained with the two doses of Ace alone. Furthermore, the cumulative frequencies of SCEs per cell were higher in the animals administered with both compounds together than in those treated with them separately. These results suggest the need to extend this type of study to other models.

Evaluation of the genotoxicity of aniline.HCl in Drosophila melanogaster

The induction of X-chromosome malsegregation, sex-linked recessive lethals and II-III autosomal translocations by aniline.HCl was investigated in Drosophila melanogaster. Nondisjunction was tested in 2 and 4 d old virgin females fed on aniline.HCl solutions (3, 5, 10 and 15%) using a system where exceptional females (XXY) and only 1/4 of the expected regular progeny are viable. After mating, the females were subcultured daily. Similarly treated 7-day-old wild-type males were used to run classical II-III translocation and recessive lethal tests; for the latter, the solutions were also injected intraabdominally. In all cases, five broods were obtained. A direct correlation was observed between concentration and toxicity. Furthermore, males were more sensitive than females, and the latter's sensitivity was higher at 4-day-old than at 2-day-old. This could be attributed to a decrease with age in the efficiency of a detoxifying mechanism, or to the generation of a toxic metabolite in older flies. Significant increases in nondisjunction were observed with 5, 10 and 15% solutions suggesting the existence of a threshold. No dose effect was detected within the range of the effective concentrations used. The increases were observed in the first subculture (representing mostly stage 14 oocyte, i.e., cells in metaphase I) and in the third subculture, representing cells in which the spindle has not yet formed, thereby pointing to a direct effect of the chemical on the chromosomes and not on the spindle. It is proposed that the second sensitivity peak detected might be the outcome of the transient loss of a protective configuration provided by the karyosome, due to its expansion in stages 9 and 10 of the developing oocytes. No sex-linked lethals or translocations were induced.