Premium
The Effects of Temperature and Heavy Water on Cell Division in Heat‐Synchronized Cells of Tetrahymena *
Author(s) -
MONER J. G.
Publication year - 1972
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.1550-7408.1972.tb03484.x
Subject(s) - heavy water , tetrahymena , cell division , division (mathematics) , deuterium , denaturation (fissile materials) , chemistry , tetrahymena pyriformis , arrhenius equation , biophysics , cell , biology , biochemistry , nuclear chemistry , physics , activation energy , arithmetic , mathematics , quantum mechanics
SYNOPSIS. A study was undertaken of the rates of cell division of heat‐synchronized cells of Tetrahymena pyriformis GL at various temperatures in water and 20, 30 and 40% heavy water. The results suggest that division rate is limited by a protein which undergoes both high and low temperature denaturation and that this protein is partially stabilized against heat‐denaturation while becoming more susceptible to cold denaturation in the presence of heavy water. Thus, the optimum temperature for division shifts upward as the heavy water concentration is increased, with a maximum shift of 1 C occurring in 40% heavy water. In addition, division activity occurs in heavy water at 34 C, a temperature at which cells kept in water are blocked. Furthermore, the sharp increase in slope seen in the low temperature portion of Arrhenius plots of the data, occurs at higher temperatures when heavy water is present. Finally, at virtually all temperatures, except the highest, heavy water has a depressive effect on division rate indicating a general inhibitory influence of deuterium‐substituted water on rate processes within the cell.