The Journal of General and Applied Microbiology
Online ISSN : 1349-8037
Print ISSN : 0022-1260
ISSN-L : 0022-1260
CORRELATION OF BIOSYNTHESIS AND SHAPE-DETERMINING PROPERTIES OF THE PEPTIDOGLYCAN AND CELL DIVISION IN TEMPERATURE-SENSITIVE MUTANTS OF ESCHERICHIA COLI
GEORGE G. KHACHATOURIANS
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1979 Volume 25 Issue 3 Pages 149-160

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Abstract

Cell division properties of temperature-sensitive mutants of Escherichia coli K-12, isolated for ampicillin resistance, altered cell-wall synthesis, and/or cross-linking of peptidoglycan chains were examined. When the incubation temperature of exponentially growing cultures of these mutants was shifted from 32° to 42°, cell division was inhibited and morphological changes were observed. This suggested that inhibition of cell division at 42° was due to a conformational change in temperature-sensitive protein(s). A return to the incubation temperature of 32°, after a short period of growth at 42°, resulted in recovery of cell division. Several of these mutants show recovery in the presence of chloramphenicol indicating that restoration of the normal phenotype occurs by the conformational change of affected protein(s). One mutant which grows into spherical cells at 42° and contains hypercross-linked peptidoglycan chains, will snot regain rod-shaped cell morphology or normal cell division in the presence of nalidixic acid, an inhibitor of DNA synthesis. In this mutant maintenance of cell shape and cell division depends on chromosome replication. These data demonstrate a direct connection between proper biosynthesis and cross-linking of peptidoglycan and cell-shape maintenance and division in E. coli.

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