Groman, Neal B. (University of Washington, Seattle) and Grace Suzuki. Quantitative study of endolysin synthesis during reproduction of lambda phages. J. Bacteriol. 86:187-194. 1963.-Endolysin is presumed to be a phage-induced enzyme participating in lysis through its destructive action on the host cell wall. A method for assaying endolysin is described, which was utilized in studying endolysin synthesis at 37 and 44 C by induced strains of K-12 (lambda), K-12 (lambdatem), and K-12 (lambda112). In all cases, endolysin was detected prior to the appearance of mature, intracellular phage and was detected earlier at 44 C than at 37 C. It was synthesized at a linear rate, as was phage, and both syntheses terminated at the same time. Surprisingly, endolysin also accumulated under conditions in which induced K-12 (lambda112) exhibited lysis inhibition. Under these conditions, endolysin concentration per induced cell was 2 to 2.5 times that produced by normally lysing K-12 (lambda). Since alterations introduced into the lytic process by temperature, mutation, or both correlate well with the timing and rate of endolysin synthesis, the data tend to support the concept that endolysin determines the kinetics of the process. However, the accumulation of endolysin during lysis inhibition suggests the need for alternative hypotheses. One hypothesis is that although endolysin action is the key to lysis some preliminary steps are required to release the enzyme so that it may contact its substrate in the cell wall. A second hypothesis is that basically the lytic process involves an alteration in the permeability barrier of the cell and that lytic enzymes such as endolysin have evolved as an auxillary but dispensable mechanism to this process.

Bacteriolysis↗

PubMed1963

[Route of infection of Japanese B encephalitis. 4. On pernasal infection].

Explore the source record for details and available documents.

Asian People↗

PubMed1962

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.

Adsorption↗

PubMed1962