STUDIES IN THE CYTDOLOGY OF Mycobacterium

II. NUCLEAR DIVISION

Abstract

In the present study, Mycobacterium 607 is taken as the material. Thebacteria are cultured on Oka-Katakura's culture-medium. The bacteria have a tendency to become spherical when they grow old on the same culture-medium. Young bacteria elongate after several nuclear divisions and then divide by fission into several individuals, each of which has one nucleus respectively. They show branches which contain one nucleus or several nuclei and the branches also cut off from the mother body. Sometimes little processes, each of which contains a nucleus, are formed at various portions of the long bacterium, cut off from the mother body and become new individuals.
The nucleus is stained with nucleus-stdining dye-solution and shows positive reaction to Feulgen's nucleal staining. When treated with DN-ase the bacterium stains faintly with the aqueous solution of gentian violet. One nucleus is seen in every cell of Mycobacterium 607, but sometimes several nuclei are seen in the long bacterium. When the bacterium divides every daughter cell contains a nucleus. Besides the nucleus, the bacterium often contains several large vacuoles.
The nucleus divides according to the type of amitosis. This type of amitosis shows some stage of the evolution to the mitosis.