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Effect of temperature on alanine uptake by membrane vesicles isolated from a psychrophilic marine bacterium
Author(s) -
Novitsky J. A.,
Morita R. Y.
Publication year - 1979
Publication title -
zeitschrift für allgemeine mikrobiologie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0044-2208
DOI - 10.1002/jobm.19790190107
Subject(s) - psychrophile , vesicle , bacteria , alanine , microbiology and biotechnology , biochemistry , chemistry , membrane , biology , amino acid , genetics
The effect of temperature on the membranes of Ant‐300, a psychrophilic marine bacterium, was studied by measuring alanine uptake by isolated membrane vesicles. Uptake was observed from 0 to 35 °C. The maximum initial rate of uptake occurred at 25 °C although more alanine was ultimately taken up at temperatures from 10 to 20 °C. An A RRHENIUS plot of these data shows a single infection point at 7.8 °C. Within 10 min, over 50% of the α‐aminoisobutyric acid taken up by whole cells at 5 °C was lost after a temperature shift to 25 °C. Vesicles preloaded with alanine at 5 °C did not become leaky when shifted to 25 °C. In addition, exposure of the vesicles to 25 °C for 30 min did not affect subsequent alanine uptake at 5 °C. The data obtained suggest that the loss of the uptake and permeability control functions of membranes from psychrophilic bacteria at elevated temperatures is not due to degeneration of the membrane itself, but rather to a control or regulatory mechanism associated with whole cells.