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D Hulanicka

Publications and source records attributed to D Hulanicka.

36 records · Page 2Linked to original sources
PubMed1982

Delayed inducibility of sulphite reductase in cysM mutants of Salmonella typhimurium under anaerobic conditions.

Salmonella typhimurium cysM mutants grow at a normal rate under aerobic conditions, but only after a lag period under anaerobic conditions. No difference in the induction of two cysteine biosynthetic enzymes--sulphite reductase and O-acetyl-L-serine sulphydrylase--in wild-type, cysK and cysM strains was observed under aerobic conditions. Under anaerobic conditions, however, the cysM strain differed from the others in showing a long delay in the induction of sulphite reductase. These observations are consistent with the assumption that the observed growth delay of the cysM mutant under anaerobic conditions is the result of abnormalities in the regulation of sulphite reductase.

Anaerobiosis↗
PubMed1981

Effect of DNA gyrase inhibitors on gene expression of the cysteine regulon.

Nalidixic acid inhibits the expression of those cysteine genes which are regulated by the cysB product, it has no affect, however, on the constitutively-expressed cysE gene. The expression of cysteine genes in a strain carrying a mutation in the nalA locus is resistant to this drug. Novobiocin affects the expression of cysteine genes similarly to nalidixic acid. The effect of nalidixic acid on the expression of genes in a cysteine constitutive mutant was studied.

Acetyltransferases↗
PubMed1981

Use of gene fusions to study expression of cysB, the regulatory gene of the cysteine regulon.

Strains of escherichia coli were constructed in which the lacZ gene is fused to cysB, the positive regulator gene of the cysteine regulon. The fusion strains were used to study the regulation of the cysB gene by assaying the fused lacZ gene product. The introduction of a cysB allele, either on a plasmid or on an episome to the fusion strains, resulted in the decrease of beta-galactosidase activity. This implies that the cysB gene expression is autoregulated by its own product. The direction of cysB gene transcription was determined to be clockwise.

Cysteine↗
PubMed1979

Constitutive mutation of cysJIH operon in a cysB deletion strain of Salmonella typhimurium.

In a cysB deletion strain a new mutation, denoted cys-2332 was isolated, which causes the constitutive expression of the cysJIH operon. cys-2332 is closely linked to cysJIH and presumably is located in the initiator region of this operon, rendering its expression independent of the cysB gene product and the internal inducer O-acetyl-L-serine. The presence of sulfite reductase (encoded by cysI and cysJ) activity in a cysB- cys-2332 double mutant indicates that cysG, which is not linked to cysJIH but is required for the synthesis of the sulfite reductase co-factor siroheme, is not controlled by cysB.

Chromosome Mapping↗
PubMed1979

Properties of cysK mutants of Escherichia coli K12.

Triazole and azaserine resistant mutants of E. coli K12 affecting cysK gene coding for O-acetylserine sulphydrylase were isolated. The cysK gene in E. coli is located in the same region of chromosome as the cycK gene in Salmonella typhimurium. All azaserine and some triazole resistant mutants require cysteine for growth at a normal rate. The cysK mutants have reduced sulphate uptake. Stability and transfer by conjugation of triazole resistant phenotype were checked. Differences in sulphate metabolism between closely related organisms E. coli and S. typhimurium are discussed.

Azaserine↗
PubMed1978

Method of isolation of cysteine constitutive mutants of the cysteine regulon in Salmonella typhimurium.

A method for selection of constitutive cysB mutation is described which takes advantage of the resistance of cysteine constitutive mutants to 1,2,4-triazole. Since cysM cysK double mutants are cysteine auxotrophs, by selecting for triazole resistance in cysM strains, mutants arising under this condition also should be constitutive for cysteine biosynthesis. Genetic analysis of mutants isolated by this technique showed that their mutational sites are located in the cysB region. Biochemical assays of cysteine enzymes, sulphite reductase and O-acetylserine sulfhydrylase of the mutants showed the derepressed level of these enzymes and the lack or slight repression by 1-cysteine.

Cysteine↗
PubMed1978

The regulatory cysK mutant of S. typhimurium.

A triazole-resistant mutant, cysK1358, showing novel properties was isolated. Biochemical analysis of this strain suggests a regulatory character of the cysK1358 mutation. The cysK1358 mutation has a pleiotropic effect: the expression of the other gene, cysA, is also altered.

Cysteine↗
PubMed1977

Sulphate permease of Escherichia coli K12.

Some properties of the sulphate transport system and the isolation of sulphate permease mutants in E. coli K12 are described. The gene coding for sulphate permease is located in the same region as the cysA gene in Salmonella typhimurium.

Chromosome Mapping↗