DNA gyrase is a prokaryotic type II topoisomerase and a major target of quinolone antibacterials. The majority of mutations conferring resistance to quinolones arise within the quinolone resistance-determining region of GyrA close to the active site (Tyr(122)) where DNA is bound and cleaved. However, some quinolone resistance mutations are known to exist in GyrB. Present structural data suggest...

Staphylococcus aureus infections are a significant cause of morbidity and mortality in health care settings. S. aureus clinical isolates vary in the function of the accessory gene regulator (agr), which governs the expression of virulence determinants, including surface and exoproteins, while agr activity has been correlated with patient outcome and treatment efficiency. Here we describe a dupl...

To further develop genetic techniques for the enteropathogen Brachyspira hyodysenteriae, the gyrB gene of this spirochete was isolated from a lambdaZAPII library of strain B204 genomic DNA and sequenced. The putative protein encoded by this gene exhibited up to 55% amino acid sequence identity with GyrB proteins of various bacterial species, including other spirochetes. B. hyodysenteriae coumer...

BACKGROUND Ofloxacin is a fluoroquinolone (FQ) used for the treatment of leprosy. FQs are known to interact with both A and B subunits of DNA gyrase and inhibit supercoiling activity of this enzyme. Mutations conferring FQ resistance have been reported to be found only in the gene encoding A subunit of this enzyme (gyrA) of M. leprae, although there are many reports on the FQ resistance-associa...

Enterococcus faecalis BM4405-1, a susceptible derivative of the VanE-type vancomycin-resistant E. faecalis strain BM4405, was obtained after growth in the presence of novobiocin, an inhibitor of the GyrB subunit of DNA gyrase. In contrast to findings for BM4405, UDP-MurNAc-L-Ala-gamma-D-Glu-L-Lys-D-Ala-D-Ala (pentapeptide[D-Ala]) was the only peptidoglycan precursor found in BM4405-1, and no Va...

Studies of the biology of Borrelia burgdorferi and the pathogenesis of Lyme disease are severely limited by the current lack of genetic tools. As an initial step toward facile genetic manipulation of this pathogenic spirochete, we have investigated gene inactivation by allelic exchange using a mutated borrelial gyrB gene that confers resistance to the antibiotic coumermycin A1 as a selectable m...

DNA gyrase is the bacterial DNA topoisomerase (topo) that supercoils DNA by using the free energy of ATP hydrolysis. The enzyme, an A(2)B(2) tetramer encoded by the gyrA and gyrB genes, catalyses topological changes in DNA during replication and transcription, and is the only topo that is able to introduce negative supercoils. Gyrase is essential in bacteria and apparently absent from eukaryote...

introduction mycobacterium tuberculosis complex (mtbc) are causative agents of human and animal tuberculosis.differentiation of mtbc members is required for appropriate treatment of individual patients and for epidemiologicalpurposes and reduction in drug resistances. material and methods 1345 patients were collected with clinical suspicions of tuberculosis who referred to the health care cente...

A rapid detection method of Pseudomonas aeruginosa based on magnetic separation and chemiluminescence was developed in this paper. Magnetic nanoparticles (MNPs) were prepared by solvothermal method with PEG-4000 as a surfactant, and then were modified. The prepared MNPs present a uniform morphology and good dispersion. The sizes of MNPs can be controlled by adjusting the dosage of FeCl3 x 6H2O....

We have determined the sequence of a 1498 base-pair region in E. coli that extends from within dnaN through recF and into the gyrB gene. An open reading frame of 1071 base pairs has been identified with the recF structural gene. By S1 mapping, we have located a transcription start point 31 base pairs upstream of gyrB. The amount of this transcript is much greater in cells that have been treated...