C. Hatzis et al., CELL-CYCLE ANALYSIS IN PHAGOTROPHIC MICROORGANISMS FROM FLOW CYTOMETRIC HISTOGRAMS, Journal of theoretical biology, 186(2), 1997, pp. 131-144
The inability of certain phagotrophic protozoa to phagocytose right be
fore and right after cell division was utilized to measure the distrib
utions of newborn and dividing cells and obtain information on the kin
etics of the cell cycle. A fluorescent microsphere labeling assay was
used in conjunction with flow cytometry to identify the non-feeding ce
lls and measure their DNA and protein distributions. These distributio
ns, which are typically bimodal, were decomposed to the two component
distributions by means of a new algorithm, which is based on the assum
ption that cells partition their DNA and the remaining cellular materi
al evenly at division. The estimated population fractions in the two n
on-feeding phases before and after division and the corresponding DNA
and protein distributions provide significant information on the kinet
ics of the cell cycle. The transient labeling experiments revealed a s
ignificant variability in the timing of the pre-division non-feeding p
hase with the smaller cells of this subpopulation spending more time i
n preparation for division. From the determined distributions of newbo
rn and dividing cells, the single-cell growth rates and division proba
bilities were also calculated. This type of analysis provides essentia
l information for the development of corpuscular, multi-staged cell po
pulation models. (C) 1997 Academic Press Limited.