Temperature and lambda phage reproduction.

Groman, Neal B. (University of Washington, Seattle) and Grace Suzuki. Temperature and lambda phage reproduction. J. Bacteriol. 84:431-437. 1962.-The effect of temperature on lambda phage production in Escherichia coli K-12 was studied, and a temperature-phage yield relationship established. Phage yield declines slowly below optimal temperature and rapidly above the optimum. An extensive comparison of phage reproduction at 37 and 44 C was made when it was observed that at 44 C phage yield was reduced to 2 to 5% that at 37 C in the absence of any significant effect on bacterial growth. The reduced yield is manifest rather uniformly in every infected cell, and the reduction is due primarily to a speed-up of the lytic process. Temperature shift-up and shift-down experiments established that the temperature-affected step or process is initiated about 25 min after adsorption. This is close to the time the first intracellular phage appears. The data indicate that heat inactivation, lysogenization or major blocks in adsorption, penetration, replication, and maturation make minor contributions, if any, to the depression of the yield. Phenotypic adaptation of phage and host to the production of a greater yield at 44 C was not observed. There was no correlation observed between the enhanced thermoresistance of free lambdavir, tr(1) phage and ability to reproduce at 44 C.