The spoT gene of Salmonella typhimurium has been identified. Mutations in spoT map between gltC and pyrE at 79 min. The spoT1 mutant has elevated levels of guanosine 5'-diphosphate-3'-diphosphate (ppGpp) during steady-state growth and exhibits a slower than normal decay of ppGpp after reversal of amino acid starvation. The spoT1 mutation elevates his operon expression but is distinct from known...

objective(s): we investigated the contribution of gyra and parc mutational mechanism in decreased ciprofloxacin susceptibility of acinetobacter baumannii isolated from burn wound infections. materials and methods: ciprofloxacin susceptibility of 50 a. baumannii isolates was evaluated by disk diffusion and agar dilution methods. pcr and sequencing were performed for detection of mutation in gyra...

26 Control of membrane permeability is a key step in regulating the intracellular 27 concentration of antibiotics. Efflux pumps confer innate resistance to a wide 28 range of toxic compounds such as antibiotics, dyes, detergents and 29 disinfectants in members of the Enterobacteriaceae. The AcrAB-TolC efflux 30 pump is involved in multidrug resistance in E. cloacae. However, the underlying 31 m...

Desulfovibrio desulfuricans G20 grows and reduces 20 mM arsenate to arsenite in lactate-sulfate media. Sequence analysis and experimental data show that D. desulfuricans G20 has one copy of arsC and a complete arsRBCC operon in different locations within the genome. Two mutants of strain G20 with defects in arsenate resistance were generated by nitrosoguanidine mutagenesis. The arsRBCC operons ...

The Gram-positive bacteria Staphylococcus aureus and Staphylococcus epidermidis are capable of attaching to a biomaterial surface and forming resistant biofilms. The identification of biomolecular and regulatory factors involved in staphylococcal adhesion and biofilm formation is needed to understand biofilm-associated infection in humans. Here, we have identified a new operon, gbaAB (glucose i...

The ability to respire sulfate linked to lactate oxidation is a key metabolic signature of the Desulfovibrio genus. Lactate oxidation by these incomplete oxidizers generates reductants through lactate dehydrogenase (LDH) and pyruvate-ferredoxin oxidoreductase (PFOR), with the latter catalyzing pyruvate conversion into acetyl-CoA. Acetyl-CoA is the source of substrate-level phosphorylation throu...

BMS-284756 (T-3811) is a novel quinolone that lacks a fluorine at the C-6 position. BMS-284756 has a broad spectrum of antibacterial activity (3, 7). The purpose of the present study was (i) to analyze the in vitro activity of the novel quinolone against mutants of Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus selected with marketed quinolones and (ii) to investiga...

UNLABELLED Mutations that cause the constitutive expression of the PHO regulon of Escherichia coli occur either in the pst operon or in the phoR gene, which encode, respectively, a high-affinity Pi transport system and a histidine kinase sensor protein. These mutations are normally selected on glycerol-2-phosphate (G2P) as the carbon source in the presence of excess Pi. The emergence of early P...

Bacillus subtilis mutants deficient in amino acid repression of the histidine utilization (hut) operon were isolated by transposon mutagenesis. Genetic characterization of these mutants indicated that they most likely contained transposon insertions within the codVWXY operon. The codY gene is required for nutritional regulation of the dipeptide permease (dpp) operon. An examination of hut expre...

The pyrimidine nucleotide biosynthetic (pyr) operon in Bacillus subtilis is regulated by a transcriptional attenuation mechanism in which PyrR, a bifunctional pyr RNA-binding attenuation protein/uracil phosphoribosyltransferase, plays a crucial role. A convenient procedure for isolation of pyrR mutants with defects in the regulation of pyr operon expression is described. The selection is based ...