Change in the physiological state of a cell population as a function of culture growth and age ( Tetrahymena geleii)

Abstract

By growing small numbers of Tetrahymena in culture pipettes, very accurate growth curves are obtainable. This method permits precise determinations of the length of lag phase, which, in turn, can be used as a measure of the physiological state of inocula withdrawn from standard cultures of various ages. The experiments demonstrate a steady shift in the physiological state of the cells and constitution of the medium during the logarithmic and stationary phases of culture growth. The total logarithmic period cannot be considered as physiologically homogeneous even though the average cell generation time remains constant. The lag phase is a period of readjustment to the medium by the newly inoculated cell population. No significant alteration of the medium is detectable during the lag period.