Project description:Transcriptome analysis of Streptococcus agalactiae (group B Streptococcus) grown under control conditions or coincubated with serine hydroxamate to induce the bacterial stringent response
Project description:Regulation of gene expression in response to variable and often adverse environmental conditions is an essential component of microbial pathogenesis. We identified the two-component regulatory system CiaRH in a screen for genes essential for the survival of Streptococcus agalactiae (Group B Streptococcus, GBS) on exposure to in vitro models of environmental stress. We constructed site-directed, non-polar deletion mutations in the regulator gene ciaR and compared the growth of CiaR mutant GBS to wild-type GBS under stressed conditions. CiaR mutant GBS are more sensitive than wild-type GBS to elevated temperature, low pH, chemical mutagens and ultraviolet light; the mutants are also more sensitive to cell-wall active antibiotics and antimicrobial peptides. CiaR mutant strains are markedly attenuated in a mouse model of GBS sepsis. To determine the genes regulated by CiaR that account for these defects, transcriptional profiling was performed using DNA microarray analysis, comparing wild-type GBS to CiaR mutant GBS under non-stressed conditions.
Project description:Streptococcus agalactiae (Lancefield’s group B Streptococcus, GBS) is a major bacterial species of genus Streptococcus and has medical and veterinary importance by affecting mainly humans (Maione et al., 2005; Johri et al., 2006), cattle (Keefe, 1997) and fish (Mian et al., 2009). The GBS is the most important pathogen for the Nile tilapia, a global commodity of the aquaculture sector, causing outbreaks of septicemia and meningoencephalitis (Hernández et al., 2009; Mian et al., 2009).
Project description:Total RNA was isolated from mid-log phase Streptococcus agalactiae cells deficient in CopY (∆copY strain GU2857), grown in Todd-Hewitt broth (THB) medium and sequenced using Illumina NextSeq500.
Project description:Total RNA was isolated from mid-log phase Streptococcus agalactiae cells deficient in SczA (∆sczA strain GU2791), grown in Todd-Hewitt broth (THB) medium and sequenced using Illumina NextSeq500.
Project description:Total RNA was isolated from mid-log phase Streptococcus agalactiae cells deficient in CovR (∆covR strain GU2400), grown in Todd-Hewitt broth (THB) medium and sequenced using Illumina NextSeq500
Project description:Total RNA was isolated from mid-log phase Streptococcus agalactiae 874391 wild-type cells grown in Todd-Hewitt broth (THB) medium and sequenced using Illumina NextSeq500
Project description:The commensal bacterium Streptococcus agalactiae is responsible for various infections in a wide variety of hosts including humans. Its broad spectrum of hosts shows its ability to acquire nutrients in variable conditions. The carbon catabolite repression allows bacteria to prioritize the uptake and the catabolism of the environmental sugars. In Gram-positive bacteria, CcpA (catabolite control protein A), a pleiotropic transcriptional regulator, plays a key role in catabolite repression. Studies have shown the involvement of carbon catabolite repression in the adaptation and stress resistance of pathogenic bacteria. The goal of this study is to determine the regulon and the role(s) of CcpA in the physiology and adaptation of S. agalactiae. To this aim, Streptococcus agalactiae strain A909 WT and its isogenic mutant ∆ccpA, obtained by allelic exchange were grown in filter-sterilized chemically defined medium (CDM) supplemented with 0,25% or 1% (w/v) of glucose. Their transcriptomes were compared under these two conditions by using RNA-seq.
Project description:The purpose of this study was to determine what S. agalactiae genes are under the control of the MtaR regulatory protein. Inactivation of the Streptococcus agalactiae mtaR gene resulted in the downregulation of 11 genes and the upregulation of 1 gene in the mtaR mutant. Genes involved in the uptake of methionine and a gene involved in the degradation of peptides were downregulated. Also, genes involved in the transport and biosynthesis of arginine were downregulated. The gene encoding the virulence factor cspA was downregulated, as well as a gene showing similarity to plasminogen activators. Thus, the expression of genes involved in both metabolic functions and virulence are under the influence of mtaR.
Project description:Streptococcus agalactiae (Lancefield’s group B Streptococcus, GBS) is a major bacterial species of genus Streptococcus and has medical and veterinary importance by affecting mainly humans (Maione et al., 2005; Johri et al., 2006), cattle (Keefe, 1997) and fish (Mian et al., 2009). The GBS is the most important pathogen for the Nile tilapia, a global commodity of the aquaculture sector, causing outbreaks of septicemia and meningoencephalitis (Hernández et al., 2009; Mian et al., 2009). This study aimed to evaluate the global abundancy of proteins among the main genotypes of GBS isolated from fish identified in Brazil using a label free shotgun liquid chromatography-ultra definition mass spectrometry (LC-UDMSE) approach and to compare the differential expression of proteins identified between isolates from fish and human.