Effects of penicillin on macromolecular synthesis and surface growth of a tolerant streptococcus as studied by computer reconstruction methods.

Journal of Bacteriology
M L HigginsG D Shockman

Abstract

Strains of Streptococcus mutans are very susceptible to growth inhibition by benzylpenicillin, but are tolerant to lysis when exposed to even high concentrations of this drug. These properties enabled this study of S. mutans GS-5 surface growth and peptidoglycan, ribonucleic acid, protein, and deoxyribonucleic acid syntheses in the absence of osmotic stabilization. Inhibition of syntheses of peptidoglycan, ribonucleic acid, and protein was dose dependent. Synthesis of peptidoglycan was most susceptible. Substantial but less severe inhibitions of ribonucleic acid and protein syntheses rapidly followed decreased peptidoglycan synthesis, whereas inhibition of deoxyribonucleic acid synthesis was delayed and minimal. Computer-assisted reconstructions of surface growth zones and poles observed in electron micrographs of replicas were performed and indicated that at low concentrations of benzylpenicillin (0.03 micrograms/ml), growth sites reached abnormally large sizes and surface/volume ratios. The observed shifts in surface/volume ratio were attributed to an inhibition of the normal constrictive division mechanism. The poles of these cells also increased in size over those of the controls, but the relatively smaller change in surfac...Continue Reading

Citations

Jun 1, 1988·Oral Microbiology and Immunology·L A Jonooby, T A Kral
Sep 1, 1987·Oral Microbiology and Immunology·J W Norys, T A Kral
Jul 1, 1983·Infection and Immunity·T A Kral, L Daneo-Moore
Nov 1, 1984·Infection and Immunity·T A Kral, M D Callaway

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