CHLOROACETALDEHYDE IS A POWERFUL INDUCER OF MITOTIC ANEUPLOIDY IN ASPERGILLUS-NIDULANS

The vinyl chloride metabolite chloroacetaldehyde (CAA) was tested for the induction of mitotic chromosome malsegregation in Aspergillus nidulans. Exposure of germinating conidia to CAA (16-64 μM) produced high rates of abnormal colonies with segregation of the whole first chromosome in the diploid strain P1, and abnormal, putative hyperploids in the haploid strain 35, indicating that CAA primarily induces abnormal chromosome segregation. Comparative assays with the known spindle poison chloral hydrate (CH), active in the dose range 6-10 mM, highlighted the unusual effectiveness of CAA in aneuploidy induction (the lowest effective concentration was 16 μM). Experiments on brain tubulin polymerization revealed an inhibitory effect by CAA only at concentrations 100-fold higher than those active in the induction of chromosome misdistribution in A. nidulans, possibly suggesting the involvement of alternative targets in its mechanism of action. o © 1990 Oxford University Press.