Three transport systems for the osmoprotectant glycine betaine operate in Bacillus subtilis: characterization of OpuD

Kappes, Rainer M.; Kempf, Bettina; Bremer, Erhard

doi:10.1128/jb.178.17.5071-5079.1996

Cited by 231 publications

(320 citation statements)

References 40 publications

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“…Of these, possible virulence genes include SAG_1135 and SAG_ 1137 that encode homologs of Gls24, a stress response protein shown to contribute to virulence in experimental enterococcal infection (18,28). A similar pattern of regulation was noted for SAG_1796 and SAG_1797, which are predicted to encode a glycine/betaine osmoregulation system implicated in adaptation to osmotic stress in other species (13,14,19,31). Differential CsrS-dependent regulation of these loci in the 2603 strain background may account for the unexpectedly high virulence of strain 2603⌬csrS.…”

Section: Differential Effects On Gene Regulation Of Inactivating Csrrmentioning

confidence: 69%

“…Gls24 has been implicated in stress response and virulence in Enterococcus faecalis (18,28). The GBS CsrRS also regulates expression of two separate operons predicted to encode components of a glycine/betaine osmoregulation system (SAG_1796 to -1797 and SAG_0241 to -0244), a system that mediates adaptation to osmotic stress in Bacillus subtilis and Lactococcus lactis (13,14,19,31). Although their role in GBS is undefined, expression of two predicted transcriptional regulators is also controlled by CsrRS: SAG_0712 encoding a putative regulator of the OmpR family and SAG_0938 encoding a predicted GntR family transcriptional regulator (11,27).…”

Section: Validation Of Microarray Results By Qrt-pcrmentioning

confidence: 99%

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Variation in the Group BStreptococcusCsrRS Regulon and Effects on Pathogenicity

et al. 2008

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CsrRS (or CovRS) is a two-component regulatory system that controls expression of multiple virulence factors in the important human pathogen group B Streptococcus (GBS). We now report global gene expression studies in GBS strains 2603V/R and 515 and their isogenic csrR and csrS mutants. Together with data reported previously for strain NEM316, the results reveal a conserved 39-gene CsrRS regulon. In vitro phosphorylationdependent binding of recombinant CsrR to promoter regions of both positively and negatively regulated genes suggests that direct binding of CsrR can mediate activation as well as repression of target gene expression. Distinct patterns of gene regulation in csrR versus csrS mutants in strain 2603V/R compared to 515 were associated with different hierarchies of relative virulence of wild-type, csrR, and csrS mutants in murine models of systemic infection and septic arthritis. We conclude that CsrRS regulates a core group of genes including important virulence factors in diverse strains of GBS but also displays marked variability in the repertoire of regulated genes and in the relative effects of CsrS signaling on CsrR-mediated gene regulation. Such variation is likely to play an important role in strain-specific adaptation of GBS to particular host environments and pathogenic potential in susceptible hosts.

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Section: Differential Effects On Gene Regulation Of Inactivating Csrrmentioning

confidence: 69%

Section: Validation Of Microarray Results By Qrt-pcrmentioning

confidence: 99%

Variation in the Group BStreptococcusCsrRS Regulon and Effects on Pathogenicity

et al. 2008

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“…Glycine betaine can be accumulated directly from the environment through three osmotically controlled uptake systems (25): OpuD, a single-component transporter, and OpuA and OpuC (ProU), multicomponent transport systems that are related to the binding protein-dependent transport system ProU from Escherichia coli (25,26,34).…”

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confidence: 99%

Synthesis of the osmoprotectant glycine betaine in Bacillus subtilis: characterization of the gbsAB genes

et al. 1996

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Synthesis of the osmoprotectant glycine betaine from the exogenously provided precursor choline or glycine betaine aldehyde confers considerable osmotic stress tolerance to Bacillus subtilis in high-osmolarity media. Using an Escherichia coli mutant (betBA) defective in the glycine betaine synthesis enzymes, we cloned by functional complementation the genes that are required for the synthesis of the osmoprotectant glycine betaine in B. subtilis. The DNA sequence of a 4.1-kb segment from the cloned chromosomal B. subtilis DNA was established, and two genes (gbsA and gbsB) whose products were essential for glycine betaine biosynthesis and osmoprotection were identified. The gbsA and gbsB genes are transcribed in the same direction, are separated by a short intergenic region, and are likely to form an operon. The deduced gbsA gene product exhibits strong sequence identity with members of a superfamily of specialized and nonspecialized aldehyde dehydrogenases. This superfamily comprises glycine betaine aldehyde dehydrogenases from bacteria and plants with known involvement in the cellular adaptation to high-osmolarity stress and drought. The deduced gbsB gene product shows significant similarity to the family of type III alcohol dehydrogenases. B. subtilis mutants with defects in the chromosomal gbsAB genes were constructed by marker replacement, and the growth properties of these mutant strains in high-osmolarity medium were analyzed. Deletion of the gbsAB genes destroyed the cholineglycine betaine synthesis pathway and abolished the ability of B. subtilis to deal effectively with high-osmolarity stress in choline-or glycine betaine aldehyde-containing medium. Uptake of radiolabelled choline was unaltered in the gbsAB mutant strain. The continued intracellular accumulation of choline or glycine betaine aldehyde in a strain lacking the glycine betaine-biosynthetic enzymes strongly interfered with the growth of B. subtilis, even in medium of moderate osmolarity. A single transcription initiation site for gbsAB was detected by high-resolution primer extension analysis. gbsAB transcription was initiated from a promoter with close homology to A -dependent promoters and was stimulated by the presence of choline in the growth medium.

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“…Osmoprotectants like glycine betaine and proline increase the cytoplasmic volume and the free water content of the cells at high salinity; therefore their accumulation allows cell proliferation under adverse environmental conditions (Record et al, 1998). In the case of B. subtilis, a family of transporters (OpuA-E) is involved in the transport of these compounds (Kappes et al, 1996;von Blohn et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Role of anionic phospholipids in the adaptation of Bacillus subtilis to high salinity

et al. 2006

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The importance of the content of anionic phospholipids [cardiolipin (CL) and phosphatidylglycerol (PG)] in the osmotic adaptation and in the membrane structure of Bacillus subtilis cultures was investigated. Insertion mutations in the three putative cardiolipin synthase genes (ywiE, ywnE and ywjE) were obtained. Only the ywnE mutation resulted in a complete deficiency in cardiolipin and thus corresponds to a true clsA gene. The osmotolerance of a clsA mutant was impaired: although at NaCl concentrations lower than 1?2 M the growth curves were similar to those of its wild-type control, at 1?5 M NaCl (LBN medium) the lag period increased and the maximal optical density reached was lower. The membrane of the clsA mutant strain showed an increased PG content, at both exponential and stationary phase, but no trace of CL in either LB or LBN medium. As well as the deficiency in CL synthesis, the clsA mutant showed other differences in lipid and fatty acids content compared to the wild-type, suggesting a cross-regulation in membrane lipid pathways, crucial for the maintenance of membrane functionality and integrity. The biophysical characteristics of membranes and large unilamellar vesicles from the wild-type and clsA mutant strains were studied by Laurdan's steady-state fluorescence spectroscopy. At physiological temperature, the clsA mutant showed a decreased lateral lipid packing in the protein-free vesicles and isolated membranes compared with the wild-type strain. Interestingly, the lateral lipid packing of the membranes of both the wild-type and clsA mutant strains increased when they were grown in LBN. In a conditional IPTG-controlled pgsA mutant, unable to synthesize PG and CL in the absence of IPTG, the osmoresistance of the cultures correlated with their content of anionic phospholipids. The transcriptional activity of the clsA and pgsA genes was similar and increased twofold upon entry to stationary phase or under osmotic upshift. Overall, these results support the involvement of the anionic phospholipids in the growth of B. subtilis in media containing elevated NaCl concentrations.

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Three transport systems for the osmoprotectant glycine betaine operate in Bacillus subtilis: characterization of OpuD

Cited by 231 publications

References 40 publications

Variation in the Group BStreptococcusCsrRS Regulon and Effects on Pathogenicity

Variation in the Group BStreptococcusCsrRS Regulon and Effects on Pathogenicity

Synthesis of the osmoprotectant glycine betaine in Bacillus subtilis: characterization of the gbsAB genes

Role of anionic phospholipids in the adaptation of Bacillus subtilis to high salinity

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