Effects of Ethidium Bromide and Several Acridine Dyes on the Kinetoplast DNA of Leishmania tropica

SYNOPSIS Whole cell DNA from Leishmania tropica has 2 peaks when banded by CsCl equilibrium density centrifugation. The main band has a buoyant density of 1.721 and the satellite band a buoyant density of 1.705, with Clostridium perfringens DNA (ρ= 1.6915) used as a reference. The satellite band has been identified as the kinetoplast DNA by purifying DNA from isolated kinetoplasts. L. tropica has the highest G + C content of both nuclear and kinetoplastic DNA thus far reported for trypanosomatids. The effects of ethidium bromide, acriflavin, proflavin, and 5‐aminoacridine on the kinetoplast of L. tropica have been compared. Ethidium bromide and acriflavin, but not proflavin or 5‐aminoacridine, induce dyskinetoplasty. L. tropica is one of the most sensitive trypanosomatids to ethidium bromide and acriflavin. Examination of the DNA from drug‐treated cells in CsCl gradients revealed a loss of the satellite band after ethidium bromide or acriflavin treatment, but not after proflavin or 5‐aminoacridine treatment. Cell division was required to produce these effects on the kinetoplast.