Estimation of time lengths of cell-cycle phases from asynchronous cultures of the basidiomycetous yeast Rhodosporidium toruloides.

Abstract

Phase-lengths in the cell division cycle of the basidiomycetous yeast Rhodosporidium toruloides Banno in an asynchronous culture at 27° were estimated by using three parameters : cell morphology, DNA synthesis, and nuclear behavior. In the yeast-extract-sucrose medium, one division cycle is 160 min, and phase-lengths of GI, S, G2, and M are calculated to be 116 min, 27 min, 10 min, and 7 min, respectively, by applying Powell's distribution function. As a dynamic phenomenon, the cell division cycle was presented in a cell clock.

Differentiation of mating tubes induced by the mating hormone rhodotorucine A during the mitotic cycle of Rhodosporidium toruloides.

“…The differentiating stage was in a late G 1 phase on the basis of data from the previous studies (7). The inhibitory effect of rhodotorucine A on DNA synthesis in a-mating type cells supported this conclusion that the stage was in the G 1 phase before initiation of DNA synthesis.…”

“…The relative bud length expressed as a ratio of bud length to mother cell length was used as an index of cell age, since the relative bud length was shown to increase at a constant rate during 60 min after the buds begin to emerge (7). Morphological changes in 481 unbudded and 595 budded cells were followed for 5 hr ( Table 1).…”

Identification of a Diploid Self-sporulating Cycle in the Basidiomycetous Yeast Rhodosporidium toruloides

“…Fluorescence intensity was measured only in non-budding yeast cells because DNA is synthesized after bud emergence in R . toruloides (Abe et al, 1984).…”

“…16). Unbudded cells were at the G I stage (Abe et al, 1984), thus the transition from yeast to hyphal cell might occur at the G I stage. The hypha formed from a polar region of the yeast cell, Table 1…”