Complete loss of kinetoplast DNA sequences induced by ethidium bromide or by acriflavine in Trypanosoma equiperdum.

A fully kinetoplastic strain of an antigenic variant of Trypanosoma equiperdum has been made dyskinetoplastic by successive treatments of infected rats with ethidium bromide or acriflavine. After seven passages in the absence of the dye, the loss of kinetoplast DNA (kDNA) is stable and complete as shown by analytical ultracentrifugation, CsCl-dye gradients, and the reassociation kinetics of in vitro-labeled kDNA. Moreover, these trypanosomes exhibit the same infectivity as the wild type. These results suggest that neither the minicircles nor the maxicircles of the kDNA network are essential to the viability and the pathogenicity of blood-stream trypanosomes.