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Effects of temperature on aggregation and the mitogen‐induced exit of lymphocytes from the resting state
Author(s) -
Hall David J.,
O'Leary James J.,
Rosenberg Andreas
Publication year - 1984
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041210126
Subject(s) - kinetics , activation energy , phase (matter) , chemistry , biophysics , substrate (aquarium) , reaction rate constant , thermodynamics , constant (computer programming) , limiting , biology , physics , ecology , computer science , programming language , mechanical engineering , organic chemistry , quantum mechanics , engineering
We have determined the temperature dependence of the kinetics of entry into the first S phase of phytohemagglutinin‐stimulated lymphocytes under conditions varying the stability of substrata over which the cells have settled. An exponential model was used to characterize entry into S phase. This model yields as parameters duration of lag period, t 0 , apparent first order rate constant for entry, k, and the number of cells committed to enter the first S phase, N A (t 0 ). Values of t 0 and N A (t 0 ) show a 1.5‐fold and 2.0‐fold decrease and increase, respectively, over a 4°C temperature range and are independent of variation in substrate stability. The temperature dependence of the apparent first‐order rate constant, k, however, is strongly influenced by stability. The observed activation energy increases from 3.0 kcal to 37 kcal when the substratum is agitated. This correlates well with reduced adherence of multicellular aggregates in agitated samples. The temperature dependencies for these three parameters are all numerically different, indicating that these parameters are determined by different rate‐limiting processes. We propose that the mechanism mirrored by k is linked to the adherence of multicellular aggregates to the substratum.