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  • 1
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 27 June 2017, Vol.114(26), pp.6824-6829
    Description: The functions of many bacterial RNA-binding proteins remain obscure because of a lack of knowledge of their cellular ligands. Although well-studied cold-shock protein A (CspA) family members are induced and function at low temperature, others are highly expressed in infection-relevant conditions. Here, we have profiled transcripts bound in vivo by the CspA family members of serovar Typhimurium to link the constitutively expressed CspC and CspE proteins with virulence pathways. Phenotypic assays in vitro demonstrated a crucial role for these proteins in membrane stress, motility, and biofilm formation. Moreover, double deletion of and fully attenuates in systemic mouse infection. In other words, the RNA ligand-centric approach taken here overcomes a problematic molecular redundancy of CspC and CspE that likely explains why these proteins have evaded selection in previous virulence factor screens in animals. Our results highlight RNA-binding proteins as regulators of pathogenicity and potential targets of antimicrobial therapy. They also suggest that globally acting RNA-binding proteins are more common in bacteria than currently appreciated.
    Keywords: RNA-Binding Protein ; Salmonella ; Bacterial Pathogenesis ; Cold-Shock Protein ; Stress Response ; Bacterial Proteins ; Cold Shock Proteins and Peptides ; Heat-Shock Proteins ; RNA-Binding Proteins ; Salmonella Infections ; Salmonella Typhimurium ; Virulence Factors
    ISSN: 00278424
    E-ISSN: 1091-6490
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  • 2
    Language: English
    In: Journal of Bacteriology, Dec, 2012, Vol.194(23-24), p.6900(9)
    Description: By coprecipitation, we identified RNA-binding proteins in the Gram-positive opportunistic pathogen Enterococcus faecalis known to be deficient of the RNA chaperone Hfq. In particular, we characterized one belonging to the cold shock protein (Csp) family (Ef2925) renamed CspR for cold shock protein RNA binding. Compared to the wild-type strain, the [delta]cspR mutant was less virulent in an insect infection model (Galleria mellonella) and exhibited a decreased persistence in mouse kidneys and a low survival rate in peritoneal macrophages. As expected, we found that the ?cspR mutant strain was more impaired in its growth than the parental strain under cold conditions and in its long-term survival under nutrient starvation. All these phenotypes were restored after complementation of the [delta]cspR mutant. In addition, Western blot analysis showed that CspR was overexpressed under cold shock conditions and in the stationary phase. Since CspR may act as an RNA chaperone, putative targets were identified using a global proteomic approach completed with transcriptomic assays. This study revealed that 19 proteins were differentially expressed in the [delta]cspR strain (9 upregulated, 10 downregulated) and that CspR mainly acted at the posttranscriptional level. These data highlight for the first time the role of the RNA-binding protein CspR as a regulator in E. faecalis and its requirement in stress response and virulence in this important human pathogen.
    Keywords: Cold Adaptation -- Research ; Enterococcus -- Physiological Aspects ; Enterococcus -- Growth ; Heat Shock Proteins -- Chemical Properties ; Microbiological Synthesis -- Research ; Protein Binding -- Research
    ISSN: 0021-9193
    Source: Cengage Learning, Inc.
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  • 3
    Language: English
    In: PLoS ONE, 2011, Vol.6(9), p.e23948
    Description: Small RNA molecules (sRNAs) are key mediators of virulence and stress inducible gene expressions in some pathogens. In this work we identify sRNAs in the Gram positive opportunistic pathogen Enterococcus faecalis . We characterized 11 sRNAs by tiling microarray analysis, 5′ and 3′ RACE-PCR, and Northern blot analysis. Six sRNAs were specifically expressed at exponential phase, two sRNAs were observed at stationary phase, and three were detected during both phases. Searches of putative functions revealed that three of them (EFA0080_EFA0081 and EFB0062_EFB0063 on pTF1 and pTF2 plasmids, respectively, and EF0408_EF04092 located on the chromosome) are similar to antisense RNA involved in plasmid addiction modules. Moreover, EF1097_EF1098 shares strong homologies with tmRNA (bi-functional RNA acting as both a tRNA and an mRNA) and EF2205_EF2206 appears homologous to 4.5S RNA member of the Signal Recognition Particle (SRP) ribonucleoprotein complex. In addition, proteomic analysis of the ΔEF3314_EF3315 sRNA mutant suggests that it may be involved in the turnover of some abundant proteins. The expression patterns of these transcripts were evaluated by tiling array hybridizations performed with samples from cells grown under eleven different conditions some of which may be encountered during infection. Finally, distribution of these sRNAs among genome sequences of 54 E. faecalis strains was assessed. This is the first experimental genome-wide identification of sRNAs in E. faecalis and provides impetus to the understanding of gene regulation in this important human pathogen.
    Keywords: Research Article ; Biology ; Medicine ; Genetics And Genomics ; Infectious Diseases ; Microbiology ; Molecular Biology ; Computational Biology ; Biophysics ; Biochemistry
    E-ISSN: 1932-6203
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  • 4
    In: Infection and Immunity, 2011, Vol. 79(7), p.2638
    Description: Phylogenetic analysis of the crystal structure of the Enterococcus faecalis SlyA (EF_3002) transcriptional factor places it between the SlyA and MarR regulator subfamilies. Proteins of these families are often involved in the regulation of genes important for bacterial virulence and stress response. To gather evidence for the role of this putative regulator in E. faecalis biology, we dissected the genetic organization of the slyA-EF_3001 locus and constructed a slyA deletion mutant as well as complemented strains. Interestingly, compared to the wild-type parent, the ΔslyA mutant is more virulent in an insect infection model (Galleria mellonella), exhibits increased persistence in mouse kidneys and liver, and survives better inside peritoneal macrophages. In order to identify a possible SlyA regulon, global microarray transcriptional analysis was performed. This study revealed that the slyA-EF_3001 locus appears to be autoregulated and that 117 genes were differentially regulated in the ΔslyA mutant. In the mutant strain, 111 were underexpressed and 6 overexpressed, indicating that SlyA functions mainly as an activator of transcription. ; p. 2638-2645.
    Keywords: Regulon ; Phylogeny ; Enterococcus Faecalis ; Gene Overexpression ; Transcription Factors ; Crystal Structure ; Loci ; Insects ; Transcription (Genetics) ; Stress Response ; Mutants ; Mice ; Models ; Kidneys ; Microarray Technology ; Liver ; Virulence ; Macrophages ; Galleria Mellonella ; Proteins;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 5
    Language: English
    In: Journal of bacteriology, December 2012, Vol.194(24), pp.6900-8
    Description: By coprecipitation, we identified RNA-binding proteins in the Gram-positive opportunistic pathogen Enterococcus faecalis known to be deficient of the RNA chaperone Hfq. In particular, we characterized one belonging to the cold shock protein (Csp) family (Ef2925) renamed CspR for cold shock protein RNA binding. Compared to the wild-type strain, the ΔcspR mutant was less virulent in an insect infection model (Galleria mellonella) and exhibited a decreased persistence in mouse kidneys and a low survival rate in peritoneal macrophages. As expected, we found that the ΔcspR mutant strain was more impaired in its growth than the parental strain under cold conditions and in its long-term survival under nutrient starvation. All these phenotypes were restored after complementation of the ΔcspR mutant. In addition, Western blot analysis showed that CspR was overexpressed under cold shock conditions and in the stationary phase. Since CspR may act as an RNA chaperone, putative targets were identified using a global proteomic approach completed with transcriptomic assays. This study revealed that 19 proteins were differentially expressed in the ΔcspR strain (9 upregulated, 10 downregulated) and that CspR mainly acted at the posttranscriptional level. These data highlight for the first time the role of the RNA-binding protein CspR as a regulator in E. faecalis and its requirement in stress response and virulence in this important human pathogen.
    Keywords: Bacterial Proteins -- Metabolism ; Cold Shock Proteins and Peptides -- Metabolism ; Enterococcus Faecalis -- Pathogenicity ; RNA-Binding Proteins -- Metabolism
    ISSN: 00219193
    E-ISSN: 1098-5530
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  • 6
    Language: English
    In: PLoS ONE, 04 November 2014, Vol.9(11), p.e111880
    Description: Infections by opportunistic bacteria have significant contributions to morbidity and mortality of hospitalized patients and also lead to high expenses in healthcare. In this setting, one of the major clinical problems is caused by Gram-positive bacteria such as enterococci and staphylococci....
    Keywords: Life Sciences ; Life Sciences ; Biochemistry, Molecular Biology ; Sciences (General)
    ISSN: 1932-6203
    E-ISSN: 1932-6203
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  • 7
    Language: English
    In: Microbiology, 02 June 2014, Vol.160(Pt_6), pp.1007-1019
    Description: Unlike proteins, RNA molecules have emerged lately as key players in regulation in bacteria. Most reviews hitherto focused on the experimental and/or in silico methods used to identify genes encoding small RNAs (sRNAs) or on the diverse mechanisms of these RNA regulators to modulate expression...
    Keywords: Life Sciences ; Life Sciences ; Biochemistry, Molecular Biology ; Biology
    ISSN: 1350-0872
    E-ISSN: 1465-2080
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  • 8
    Language: English
    In: Infection and immunity, September 2014, Vol.82(9), pp.3599-611
    Description: Candidate small RNAs (sRNAs) have recently been identified in Enterococcus faecalis, a Gram-positive opportunistic pathogen, and six of these candidate sRNAs with unknown functions were selected for a functional study. Deletion mutants and complemented strains were constructed, and their virulence was tested. We were unable to obtain the ef0869-0870 mutant, likely due to an essential role, and the ef0820-0821 sRNA seemed not to be involved in virulence. In contrast, the mutant lacking ef0408-0409 sRNA, homologous to the RNAII component of the toxin-antitoxin system, appeared more virulent and more able to colonize mouse organs. The three other mutants showed reduced virulence. In addition, we checked the responses of these mutant strains to several stresses encountered in the gastrointestinal tract or during the infection process. In parallel, the activities of the sRNA promoters were measured using transcriptional fusion constructions. To attempt to identify the regulons of these candidate sRNAs, proteomics profiles of the mutant strains were compared with that of the wild type. This showed that the selected sRNAs controlled the expression of proteins involved in diverse cellular processes and the stress response. The combined data highlight the roles of certain candidate sRNAs in the adaptation of E. faecalis to environmental changes and in the complex transition process from a commensal to a pathogen.
    Keywords: Enterococcus Faecalis -- Genetics ; Stress, Physiological -- Genetics ; Virulence -- Genetics
    ISSN: 00199567
    E-ISSN: 1098-5522
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  • 9
    Language: English
    In: Infection and immunity, January 2015, Vol.83(1), pp.364-71
    Description: We previously showed that the mutant strain of Enterococcus faecalis lacking the transcriptional regulator SlyA is more virulent than the parental strain. We hypothesized that this phenotype was due to overexpression of the second gene of the slyA operon, ef_3001, renamed pmvE (for polyamine metabolism and virulence of E. faecalis). PmvE shares strong homologies with N(1)-spermidine/spermine acetyltransferase enzymes involved in the metabolism of polyamines. In this study, we used an E. faecalis strain carrying the recombinant plasmid pMSP3535-pmvE (V19/p3535-pmvE), which allows the induction of pmvE by addition of nisin. Thereby, we showed that the overexpression of PmvE increased the virulence of E. faecalis in the Galleria mellonella infection model, as well as the persistence within peritoneal macrophages. We were also able to show a direct interaction between the His-tagged recombinant PmvE (rPmvE) protein and putrescine by the surface plasmon resonance (SPR) technique on a Biacore instrument. Moreover, biochemical assays showed that PmvE possesses an N-acetyltransferase activity toward polyamine substrates. Our results suggest that PmvE contributes to the virulence of E. faecalis, likely through its involvement in the polyamine metabolism.
    Keywords: Acetyltransferases -- Metabolism ; Enterococcus Faecalis -- Growth & Development
    ISSN: 00199567
    E-ISSN: 1098-5522
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  • 10
    Language: English
    In: Microbiology, 27 September 2013, Vol.159(Pt_10), pp.2153-2161
    Description: CspR has been characterized recently as a cold-shock RNA-binding protein in Enterococcus faecalis, a natural member of the gastro-intestinal tract capable of switching from a commensal relationship with the host to an important nosocomial pathogen. In addition to its involvement in the...
    Keywords: Life Sciences ; Life Sciences ; Biochemistry, Molecular Biology ; Biology
    ISSN: 1350-0872
    E-ISSN: 1465-2080
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