Chromosomal Abnormalities resulting from Ethidium Bromide Treatment

Abstract

THE phenanthridine compound ethidium bromide (EB) has been extensively used as a trypanocidal agent. Its pharmacological effectiveness must be partially based on its intercalation with DNA molecules^1,2, which alters the structure and hence the physical properties of the nucleic acid and which has recently facilitated the separation of molecules of mitochondrial DNA from those of nuclear origin^3–5. One of us (J. B.) has recently studied the effects of EB on morphogenesis in Acetabularia, amphibian and sea urchin embryos⁶. In the latter it was found that the effects of low concentrations of EB (10 µg/ml.) are very similar to those of actinomycin; as recently described by Gliudice et al.⁷ for actinomycin, the formation of the skeleton is particularly sensitive to EB. At higher concentrations (20–30 (µg/ml.), however, in contrast to actinomycin, EB quickly stops cleavage and induces mitotic abnormalities. We describe the abnormalities in detail here.