Electron microscopy of kinetoplastic DNA from Trypanosoma mega

The electron microscopical aspect of kinetoplast DNA has been studied in preparations obtained by osmotic disruption of isolated organelles. A large amount of this DNA appears to be of large molecular size. This is apparently at variance with the observations, made by others using a different technical approach, of kinetoplast DNA consisting mainly of small circular molecules of constant size. As a homogeneous population of small circles (0.74 mum in contour length) could also be seen in our samples, the possibility that at least two different kinds of DNA exist in the kinetoplast is discussed.