Positive selection of mutants with cell envelope defects of a Salmonells typhimurium strain hypersensitive to the products of genes hisF and hisH.

AUTOR(ES)

Antón, D N

RESUMO

Strain SB564 and its derivative DA78 are hypersensitive to the inhibitory action of the proteins coded for by genes hisF and hisH on cell division. Transduction of hisO1243, a regulatory mutation that elicits a very high level of expression of the histidine operon, into these strains resulted in the production of long filamentous cells carrying large "balloons" and in growth failure. Forty-one hisO1242 derivatives that escaped inhibition were isolated. These strains showed a large variety of alterations, many of which were related to the cell envelope. The more-frequent alterations included: changes in cell shape, increased sensitivity to one or more of several drugs (deoxycholate, cycloserine, penicillin, novobiocin, acridine orange), increased autolytic activity in alkaline buffer, anomalous fermentation of maltose on eosin--methylene blue plates, and temperature-conditional cell division. The alterations are produced, in some of the strains, by pleiotropic mutations in gene envB (Antón, Mol, Gen. Genet. 160:277--286, 1978) or envD (Antón and Orce, Mol. Gen. Genet. 144:97--105, 1976). Strains affected in divC, divD, and rodA loci have also been identified. Genetic analysis has shown that several strains carry more than one envelope mutation. It is assumed that envelope mutations are positively selected because they somehow alleviate the particularly severe inhibition of cell division caused, in strains SB564 and DA78, by the excessive synthesis of hisF and hisH gene products.

Documentos Relacionados

• Suppression of the pleiotropic effects of HisH and HisF overproduction identifies four novel loci on the Salmonella typhimurium chromosome: osmH, sfiW, sfiX, and sfiY.
• Developing an energy landscape for the novel function of a (β/α)8 barrel: Ammonia conduction through HisF
• Histidine Mutants Requiring Adenine: Selection of Mutants with Reduced hisG Expression in SALMONELLA TYPHIMURIUM
• Thermal fluctuations between conformational substates of the Fe(2+)-HisF8 linkage in deoxymyoglobin probed by the Raman active Fe-N epsilon (HisF8) stretching vibration.
• Comparison of the cell envelope structure of a lipopolysaccharide-defective (heptose-deficient) strain and a smooth strain of Salmonella typhimurium.