PARAMETRIC ANALYSIS OF LENGTH DISTRIBUTIONS OF THE FISSION YEAST, SCHIZOSACCHAROMYCES-POMBE, IN CHEMOSTAT CULTURE

Assuming that cells grow exponentially in length, the cycle of cells i n chemostat cultures was analyzed parametrically by the age-size metho d (James, T.W. et al., Exp. Cell Res., 94, 267-276, 1975), which fitte d well to the raw data of the length distribution. For simulation, we used the cell length and coefficient of variation at division from emp irical data. The cell length and coefficient of variation at birth, th e specific growth rate in extension, and the proportion of growing cel ls were estimated for simulation. We found that the stop-grow point of a cycle depended on the culture conditions: cells grown at D = 0.247 h(-1) in the chemostat culture had the stop-grow point at 0.72 of the cycle, similar to cells growing exponentially in the batch culture. Ce lls grown at D = 0.126 h(-1) and D = 0.062 h(-1) in the chemostat cult ures had the stop-grow points at 0.85 and 0.97 of the cycles, respecti vely. There was a sub-population of nongrowing cells estimated.