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N B GROMAN

Publications and source records attributed to N B GROMAN.

At least 19 recordsLinked to original sources
PubMed1964

INFECTIOUS BOVINE RHINOTRACHEITIS VIRUS REPLICATION, CYTOPATHOLOGY, AND PLAQUE FORMATION IN THE PRESENCE AND ABSENCE OF NUCLEIC ACID ANALOGUES.

Stevens, Jack G. (University of Washington, Seattle), and Neal B. Groman. Infectious bovine rhinotracheitis virus replication, cytopathology, and plaque formation in the presence and absence of nucleic acid analogues. J. Bacteriol. 87:446-453. 1964.-Cytopathology induced by infectious bovine rhinotracheitis (IBR) virus was correlated with the one-step growth cycle. Nuclear alterations, including the development of inclusion bodies, preceded the appearance of virus. It was found that similar effects occurred in the presence of 5-bromodeoxyuridine (BUDR) and 5-fluorodeoxyuridine (FUDR), compounds which depress the yield of "standard" virus from a range of 116 to 500 to less than 0.5 plaque-forming units per cell. As with known members of the herpesvirus group, IBR virus plaques developed and enlarged indefinitely in the presence of specific antibody. An analysis of the mechanism operative in this process was undertaken. The evidence suggested that neither viral nor subviral particles capable of replicating "standard" virus passed between cells during the first 8 hr of infection. This is the time preceding the release of extracellular virus from initially infected cells. With BUDR and FUDR, it was shown that plaques also developed in this system in the virtual absence of production of "standard" infectious virus. However, a class of analogue-dependent virus was found which may have been at least partly responsible for plaque formation in the analogue-treated system. The relative contributions of subviral particles or of a self-sustaining molecular disorganization to the process have not been completely assessed as yet.

Animals↗
PubMed1963

QUANTITATIVE STUDY OF ENDOLYSIN SYNTHESIS DURING REPRODUCTION OF LAMBDA PHAGES.

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↗
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

Temperature and the reproduction of lambda-phage mutants.

Groman, Neal B. (University of Washington, Seattle). Temperature and the reproduction of two lambda-phage mutants. J. Bacteriol. 84:438-445. 1962.-A comparative study of phage lambda, and mutants lambdatem and lambda11(2), was made, with particular emphasis on the effect of elevated temperature (44 C) on phage reproduction. Phage lambdatem was selected at 44 C and lambda11(2) was isolated from the late-lysing fraction of bacteria at 37 C. All three phages are similar in their host range, immunity pattern, and in the rate of inactivation of free phage by anti-lambda antibody and heat. Differences were observed in their plaque size and in their relative plating efficiency at 37 and 44 C. One-step growth curve studies showed that phages lambda and lambdatem are similar in the time intracellular phage appears and in their rate of maturation at 37 C. These time and rate parameters were unchanged at 44 C. Both lambda and lambdatem exhibited a reduced latent period at 44 C. However, the latent period of lambdatem was longer than that of lambda at both 37 and 44 C, and its relative 44 C/37 C yield was about 40% while that of lambda is about 3%. Phage lambdatem may be characterized as a lambda mutant with an altered latent period. Phage lambda11(2) was similar to lambda and lambdatem at 37 C, but at 44 C behaved quite differently. The time of appearance of intracellular phage was delayed, compared to 37 C, and the rate of maturation was slower. Phage production at 44 C was about 16% that at 37 C. On further investigation, it was observed that induced Escherichia coli K-12 (lambda11(2)) failed to lyse at 44 C, although it did lyse at 37 C. Lysis inhibition was imposed almost immediately by transferring cells from 37 C to 44 C at any time during the reproductive cycle, including the lytic phase. The behavior of lambda11(2) at 44 C disposed of the possibility that the lytic step was the only step in the phage cycle sensitive to variations in temperature. However, it appeared that the lytic step was a consistant target for its action.

Bacteriophage lambda↗