Damage and derepression in Escherichia coli resulting from growth at low temperatures.

Ng, Henry (University of California, Davis), John L. Ingraham, and Allen G. Marr. Damage and derepression in Escherichia coli resulting from growth at low temperatures. J. Bacteriol. 84:331-339. 1962.-Exponentially growing cultures of Escherichia coli ML30 were subjected to abrupt changes in temperature. If the change in temperature was made within the range of temperature in which the temperature characteristic, mu, is constant, exponential growth resumed immediately at a rate characteristic of the new temperature. But, if the shifts were made to or from a temperature below the range of constant mu, the initial growth rate was intermediate to the rates normal for the initial and final temperatures. The results indicate that growth at low temperature alters or damages the cell in a way that reduces the growth rate. A period of growth at higher temperature is required to correct the damage. Release from glucose repression of the induction of beta-galactosidase occurs at a temperature coincident with low-temperature damage. Derepression may be the damage that results from growth at low temperature.