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Variation of Cell and Nuclear Volume of Tetrahymena pyriformis with Three Parameters of Growth: Age of Culture, Age of Cell, and Generation Time *
Author(s) -
SUMMERS L. G.
Publication year - 1963
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1963.tb01679.x
Subject(s) - volume (thermodynamics) , tetrahymena pyriformis , phase (matter) , logarithm , cell division , nucleus , growth curve (statistics) , tetrahymena , chemistry , cell , biology , physics , thermodynamics , mathematics , statistics , biochemistry , microbiology and biotechnology , mathematical analysis , organic chemistry
SYNOPSIS. Cell volume and nuclear volume of Tetrahymena pyriformis strains HS and E , grown on a defined medium, were measured as a function of age of culture, age of cell and generation time. The volume of an “average” single cell between divisions was calculated for logarithmic phase cultures by using volume distributions and difference equations. Cell volume measurements were made by compressing the cells to known thickness and measuring the area from photomicrographs. The nuclear volume was determined from diameter measurements of the nucleus by assuming the shape of a sphere. The cell volume decreased from the lag phase to the logarithmic phase and reached a minimum at the end of the logarithmic phase. It increased again during the stationary phase. The nuclear volume also decreased from the lag to logarithmic phase, but continued to decrease in the stationary phase until it reached the nuclear volume of the daughter cell. The average single cell volume increased at a constant rate for 85% of the generation time, at which point the rate diminished to zero. The nuclear volume showed no increase until 35% of the generation time had passed. It then increased at an accelerated rate which diminished just before division. Both the average cell and nuclear volumes decreased with increase in temperature until the optimum temperature was reached, at which point they increased again. There were no appreciable differences in volume changes for cells grown on different media.