Cytology of Rhodotorula glutinis.

Thyagarajan, T. R. (Cornell University, Ithaca, N. Y.) and H. B. Naylor. Cytology of Rhodotorula glutinis. J. Bacteriol. 83:127-136. 1962.-The structure and manner of division of nuclei in actively dividing cells of Rhodotorula glutinis were studied with the phase contrast microscope. The nucleus consists of a dense central body, surrounded by a shell of optically uniform material of low density. The entire structure is enclosed within a nuclear membrane. Various fixation and staining techniques were employed to confirm the observations made from living cells. Since the dense central body is Feulgen-negative and is readily stained by iron alum hematoxylin, it is identified as the nucleolus. The material surrounding the nucleolus has no marked affinity for hematoxylin but is Feulgen-positive and stains intensely with Giemsa and basic fuchsin. The nucleus appears to divide by a process of elongation and constriction during which roughly half of the nucleolus, along with the surrounding chromatin, passes into the bud. The nuclear membrane was found to persist during all stages of division. Vacuoles were seldom observed in actively dividing cells. The nucleus of R. glutinis is similar in structure to the nuclei of higher organisms, but its behavior during division is quite different.