title: Genetic and physiological analysis of an envB spherelike mutant of Escherichia coli K-12 and characterization of its transductants.
abstract: The envB1 mutation mediating a distorted cell morphology of Escherichia coliK-12 was cotransducible with strA, aroE, aspB, and argG. The mapping data is consistent with a gene location for envB around 62.5 min. In partial diploids envB1 was recessive to its wild-type allele. The original envB mutant contained a second mutation in a locus denoted sloB close to strA. The following gene order is suggested: sloB-strA-aroE-envB-aspB-argG. The sloB1 mutation caused a marked reduction in the growth rate of both envB and envB+ strains. Moreover, this mutation in the presence of envB1 appears to increase the ratio between deoxyribonucleic acid and protein in cells growing in rich medium. The phenotypic properties of envB1, sloB+ and envB+ transductants were characterized. Cells with envB1, sloB+ genotype were hypersensitive to several penicillins including the beta-lactam compound, amidino penicillin. Penicillin hypersensitivity could not be explained by increased outer membrane penetrability. The original envB mutant (envB1,SLOB1), as well as envB1, sloB1 or envB+, SLOB1 transductants were resistant to amidino penicillin. Resistance was explained by the slow growth rate mediated by the sloB1 mutation. The similarity between envB cells and wild-type cells treated with sublethal concentrations of amidino penicillin was emphasized.
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis; D002874:Chromosome Mapping; D004269:DNA, Bacterial / Q000032:analysis; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D005808:Genes, Recessive; D009154:Mutation; D010403:Penicillin Resistance; D010406:Penicillins / Q000494:pharmacology; D010641:Phenotype; D011830:Radiation Effects; D014161:Transduction, Genetic; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D010406:Penicillins