Fine structure and replication of the kinetoplast of Trypanosoma lewisi.

The kinetoplastic DNA of Trypanosoma lewisi is described as a filamentous body lying within a mitochondrion, with the filaments oriented parallel to the long axis of the cell. The manner of fixation, the replicative state, and perhaps the physiological state of the cell, may result in slight morphological differences among such bodies. The kinetoplastic DNA replicates to form "left" and "right" rather than "upper" and "lower" members, and both the kinetoplast and nucleus incorporate radiothymidine as shown by radioautography. Radioautographic analyses suggest a random incorporation of radiothymidine by kinetoplasts. Silver grains were occasionally observed over centriolar elements. Finally, the observations are discussed with respect to the sequential replication of the aforementioned organelles by T. lewisi.