Alexander V. Dmitriev

Learn More
The expression of many virulence-associated genes in Streptococcus pyogenes is controlled in a growth phase-dependent manner. Unlike the model organisms Escherichia coli and Bacillus subtilis, such regulation is apparently not dependent upon alternative sigma factors but appears to rely on complex interactions among several transcriptional regulators,(More)
Human isolates of Streptococcus pyogenes, a Gram-positive bacterium, are characterized by significant genetic and phenotypic variation. The rgg locus, also known as ropB, is a global transcriptional regulator of genes associated with metabolism, stress responses, and virulence in S. pyogenes strain NZ131 (serotype M49). To assess the breadth of the Rgg(More)
Streptococcus pyogenes Rgg is a transcriptional regulator that interacts with the cofactor LacD.1 to control growth phase-dependent expression of genes, including speB, which encodes a secreted cysteine protease. LacD.1 is thought to interact with Rgg when glycolytic intermediates are abundant in a manner that prevents Rgg-mediated activation of speB(More)
Streptococcus pyogenes is responsible for approximately 500,000 deaths each year worldwide. Many of the associated virulence factors are expressed in a growth phase-dependent manner. To identify growth phase-associated changes in expression on a genomescale, the exponential and stationary phase transcriptomes and proteomes of S. pyogenes strain NZ131(More)
Treatment of Allium cepa L. cellsuspension cultures with a biotic elicitor derived from the fungus Botrytis cinerea, resulted in phytoalexin synthesis. Two phytoalexins, 5-octylcyclopenta-1,3-dione and 5-hexyl-cyclopenta-1,3-dione, were accumulated in cultured onion cells. Removal of extracellular Ca2+ by the calcium chelator ethylene glycol(More)
A chromosomal DNA fragment of 8992 bp in size that has not been previously identified inStreptococcus agalactiae, was cloned and sequenced from strain 98-D60C. In particular, this 8992-bp fragment contained genes homologous to the sensor histidine kinase gene and the DNA-binding response-regulator gene ofStreptococcus pneumoniae, andS. agalactiae bac gene.(More)
The presence and restriction fragment length polymorphism (RFLP) of DNA fragments hybridizing with virulence and “house keeping” gene probes were analyzed for 87 group B streptococcal (GBS) strains of human and bovine origin. Most characteristics obtained for bovine strains were similar when compared with those for human strains. The most significant degree(More)
A collection of 45 epidemiologically unrelated Streptococcus agalactiae strains (group B Streptococcus, GBS), belonging to different serotypes, isolated from pregnant women in China and Russia was studied. Strains were characterized by pulsed-field gel electrophoresis (PFGE) employing hybridization with nine genes potentially involved in virulence.(More)
A collection of 113 epidemiologically unrelated Streptococcus agalactiae strains were studied (group B streptococcus; GBS): they belonged to different serotypes and were isolated from pregnant women in China and Russia. The insertion sequence ISSa4 was found in 21 of 113 strains (18,6%). All of the strains with ISSa4 belonged to serotypes II and II/c and(More)
BACKGROUND & OBJECTIVES The goal of the present study was to improve and simplify the diagnosis of Streptococcus agalactiae (group B Streptococcus, GBS) infection for routine clinical practice. METHODS A total of 71 clinical samples were tested by microbiologic culture, counter immunoelectrophoresis (CIE) and PCR described in the literature. Southern(More)