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  • 1
    Online Resource
    Online Resource
    Oxford University Press (OUP) ; 1992
    In:  Nucleic Acids Research Vol. 20, No. 9 ( 1992), p. 2379-2379
    In: Nucleic Acids Research, Oxford University Press (OUP), Vol. 20, No. 9 ( 1992), p. 2379-2379
    Type of Medium: Online Resource
    ISSN: 0305-1048 , 1362-4962
    RVK:
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 1992
    detail.hit.zdb_id: 1472175-2
    SSG: 12
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  • 2
    In: mSphere, American Society for Microbiology, Vol. 2, No. 1 ( 2017-02-22)
    Abstract: The catalase-negative, facultative anaerobe Streptococcus pneumoniae D39 is naturally resistant to hydrogen peroxide (H 2 O 2 ) produced endogenously by pyruvate oxidase (SpxB). Here, we investigate the adaptive response to endogenously produced H 2 O 2 . We show that lactate oxidase, which converts lactate to pyruvate, positively impacts pyruvate flux through SpxB and that ΔlctO mutants produce significantly lower H 2 O 2 . In addition, both the SpxB pathway and a candidate pyruvate dehydrogenase complex (PDHC) pathway contribute to acetyl coenzyme A (acetyl-CoA) production during aerobic growth, and the pyruvate format lyase (PFL) pathway is the major acetyl-CoA pathway during anaerobic growth. Microarray analysis of the D39 strain cultured under aerobic versus strict anaerobic conditions shows upregulation of spxB , a gene encoding a rhodanese-like protein (locus tag spd0091 ), tpxD , sodA , piuB , piuD , and an Fe-S protein biogenesis operon under H 2 O 2 -producing conditions. Proteome profiling of H 2 O 2 -induced sulfenylation reveals that sulfenylation levels correlate with cellular H 2 O 2 production, with endogenous sulfenylation of ≈50 proteins. Deletion of tpxD increases cellular sulfenylation 5-fold and has an inhibitory effect on ATP generation. Two major targets of protein sulfenylation are glyceraldehyde-3-phosphate dehydrogenase (GapA) and SpxB itself, but targets also include pyruvate kinase, LctO, AdhE, and acetate kinase (AckA). Sulfenylation of GapA is inhibitory, while the effect on SpxB activity is negligible. Strikingly, four enzymes of capsular polysaccharide biosynthesis are sulfenylated, as are enzymes associated with nucleotide biosynthesis via ribulose-5-phosphate. We propose that LctO/SpxB-generated H 2 O 2 functions as a signaling molecule to downregulate capsule production and drive altered flux through sugar utilization pathways. IMPORTANCE Adaptation to endogenous oxidative stress is an integral aspect of Streptococcus pneumoniae colonization and virulence. In this work, we identify key transcriptomic and proteomic features of the pneumococcal endogenous oxidative stress response. The thiol peroxidase TpxD plays a critical role in adaptation to endogenous H 2 O 2 and serves to limit protein sulfenylation of glycolytic, capsule, and nucleotide biosynthesis enzymes in S. pneumoniae .
    Type of Medium: Online Resource
    ISSN: 2379-5042
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2017
    detail.hit.zdb_id: 2844248-9
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  • 3
    Online Resource
    Online Resource
    American Society for Microbiology ; 2010
    In:  Journal of Bacteriology Vol. 192, No. 1 ( 2010-01), p. 264-279
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 192, No. 1 ( 2010-01), p. 264-279
    Abstract: We report a search for small RNAs (sRNAs) in the low-GC, Gram-positive human pathogen Streptococcus pneumoniae . Based on bioinformatic analyses by Livny et al. (J. Livny, A. Brencic, S. Lory, and M. K. Waldor, Nucleic Acids Res. 34: 3484-3493, 2006), we tested 40 candidates by Northern blotting and confirmed the expression of nine new and one previously reported (CcnA) sRNAs in strain D39. CcnA is one of five redundant sRNAs reported by Halfmann et al. (A. Halfmann, M. Kovacs, R. Hakenbeck, and R. Bruckner, Mol. Microbiol. 66: 110-126, 2007) that are positively controlled by the CiaR response regulator. We characterized 3 of these 14 sRNAs: Spd-sr17 (144 nucleotides [nt]; decreased in stationary phase), Spd-sr37 (80 nt; strongly expressed in all growth phases), and CcnA (93 nt; induced by competence stimulatory peptide). Spd-sr17 and CcnA likely fold into structures containing single-stranded regions between hairpin structures, whereas Spd-sr37 forms a base-paired structure. Primer extension mapping and ectopic expression in deletion/insertion mutants confirmed the independent expression of the three sRNAs. Microarray analyses indicated that insertion/deletion mutants in spd-sr37 and ccnA exerted strong cis -acting effects on the transcription of adjacent genes, indicating that these sRNA regions are also cotranscribed in operons. Deletion or overexpression of the three sRNAs did not cause changes in growth, certain stress responses, global transcription, or virulence. Constitutive ectopic expression of CcnA reversed some phenotypes of D39 Δ ciaR mutants, but attempts to link CcnA to -E to comC as a target were inconclusive in ciaR + strains. These results show that S. pneumoniae , which lacks known RNA chaperones, expresses numerous sRNAs, but three of these sRNAs do not strongly affect common phenotypes or transcription patterns.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2010
    detail.hit.zdb_id: 1481988-0
    SSG: 12
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  • 4
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 200, No. 11 ( 2018-06)
    Abstract: Antimicrobial peptides (AMPs), including chemokines, are produced during infections to kill pathogenic bacteria. To fill in gaps in knowledge about the sensitivities of Streptococcus pneumoniae and related Streptococcus species to chemokines and AMPs, we performed a systematic, quantitative study of inhibition by chemokine CXCL10 and the AMPs LL-37 and nisin. In a standard Tris-glucose buffer (TGS), all strains assayed lacked metabolic activity, as determined by resazurin (alamarBlue) reduction, and were extremely sensitive to CXCL10 and AMPs (50% inhibitory concentration [IC 50 ], ∼0.04 μM). In TGS, changes in sensitivities caused by mutations were undetectable. In contrast, strains that retained reductive metabolic activity in a different assay buffer (NPB [10 mM sodium phosphate {pH 7.4}, 1% {vol/vol} brain heart infusion {BHI} broth] ) were less sensitive to CXCL10 and AMPs than in TGS. In NPB, mutants known to respond to AMPs, such as Δ dlt mutants lacking d -alanylation of teichoic acids, exhibited the expected increased sensitivity. S. pneumoniae serotype 2 strain D39 was much (∼10-fold) less sensitive to CXCL10 killing in NPB than serotype 4 strain TIGR4, and the sensitivity of TIGR4 was unaffected by the absence of capsule. Candidate screening of strain D39 revealed that mutants lacking Opp (Δ amiACDEF ) oligopeptide permease were significantly more resistant to CXCL10 than the wild-type strain. This increased resistance could indicate that Opp is a target for CXCL10 binding or that it transports CXCL10 into cells. Finally, Δ ftsX or Δ ftsE mutants of Bacillus subtilis or amino acid changes that interfere with FtsX function in S. pneumoniae did not impart resistance to CXCL10, in contrast to previous results for Bacillus anthracis , indicating that FtsX is not a general target for CXCL10 binding. IMPORTANCE S. pneumoniae (pneumococcus) is a human commensal bacterium and major opportunistic respiratory pathogen that causes serious invasive diseases, killing millions of people worldwide annually. Because of its increasing antibiotic resistance, S. pneumoniae is now listed as a “superbug” for which new antibiotics are urgently needed. This report fills in knowledge gaps and resolves inconsistencies in the scientific literature about the sensitivity of S. pneumoniae and related Streptococcus pathogens to chemokines and AMPs. It also reveals a new mechanism by which S. pneumoniae can acquire resistance to chemokine CXCL10. This mechanism involves the Opp (AmiACDEF) oligopeptide transporter, which plays additional pleiotropic roles in pneumococcal physiology, quorum sensing, and virulence. Taking the results together, this work provides new information about the way chemokines kill pneumococcal cells.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2018
    detail.hit.zdb_id: 1481988-0
    SSG: 12
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  • 5
    In: Molecular Microbiology, Wiley, Vol. 100, No. 6 ( 2016-06), p. 1039-1065
    Abstract: In ellipsoid‐shaped ovococcus bacteria, such as the pathogen Streptococcus pneumoniae (pneumococcus), side‐wall (peripheral) peptidoglycan (PG) synthesis emanates from midcells and is catalyzed by the essential class B penicillin‐binding protein PBP2b transpeptidase (TP). We report that mutations that inactivate the pneumococcal YceG‐domain protein, Spd_1346 (renamed MltG), remove the requirement for PBP2b. Δ mltG mutants in unencapsulated strains accumulate inactivation mutations of class A PBP1a, which possesses TP and transglycosylase (TG) activities. The ‘synthetic viable’ genetic relationship between Δ pbp1a and Δ mltG mutations extends to essential Δ mreCD and Δ rodZ mutations that misregulate peripheral PG synthesis. Remarkably, the single MltG(Y488D) change suppresses the requirement for PBP2b, MreCD, RodZ and RodA. Structural modeling and comparisons, catalytic‐site changes and an interspecies chimera indicate that pneumococcal MltG is the functional homologue of the recently reported MltG endo‐lytic transglycosylase of Escherichia coli . Depletion of pneumococcal MltG or mltG (Y488D) increases sphericity of cells, and MltG localizes with peripheral PG synthesis proteins during division. Finally, growth of Δ pbp1a Δ mltG or mltG (Y488D) mutants depends on induction of expression of the WalRK TCS regulon of PG hydrolases. These results fit a model in which MltG releases anchored PG glycan strands synthesized by PBP1a for crosslinking by a PBP2b:RodA complex in peripheral PG synthesis.
    Type of Medium: Online Resource
    ISSN: 0950-382X , 1365-2958
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2016
    detail.hit.zdb_id: 1501537-3
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  • 6
    Online Resource
    Online Resource
    Wiley ; 1994
    In:  Molecular Microbiology Vol. 13, No. 1 ( 1994-07), p. 35-49
    In: Molecular Microbiology, Wiley, Vol. 13, No. 1 ( 1994-07), p. 35-49
    Type of Medium: Online Resource
    ISSN: 0950-382X , 1365-2958
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 1994
    detail.hit.zdb_id: 1501537-3
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  • 7
    Online Resource
    Online Resource
    Wiley ; 1992
    In:  Journal of Neurobiology Vol. 23, No. 6 ( 1992-08), p. 720-738
    In: Journal of Neurobiology, Wiley, Vol. 23, No. 6 ( 1992-08), p. 720-738
    Type of Medium: Online Resource
    ISSN: 0022-3034 , 1097-4695
    URL: Issue
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 1992
    detail.hit.zdb_id: 1474900-2
    detail.hit.zdb_id: 2266191-8
    SSG: 12
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  • 8
    In: mBio, American Society for Microbiology, Vol. 2, No. 5 ( 2011-11)
    Abstract: Two patterns of Sec translocase distribution, an ExPortal microdomain in certain ovococcus-shaped species like Streptococcus pyogenes and a spiral pattern in rod-shaped species like Bacillus subtilis , have been reported for Gram-positive bacteria. This study provides evidence for a third pattern of Sec localization in the ovococcus human pathogen Streptococcus pneumoniae . The SecA motor and SecY channel subunits of the Sec translocase localize dynamically to different places in the mid-cell region during the division cycle of exponentially growing, but not stationary-phase, S. pneumoniae . Unexpectedly, the S. pneumoniae HtrA (HtrA Spn ) protease/chaperone principally localizes to cell equators and division septa. The coincident localization of SecA Spn , SecY Spn , and HtrA Spn to regions of peptidoglycan (PG) biosynthesis in unstressed, growing cells suggests that the pneumococcal Sec translocase directs assembly of the PG biosynthesis apparatus to regions where it is needed during division and that HtrA Spn may play a general role in quality control of proteins exported by the Sec translocase.
    Type of Medium: Online Resource
    ISSN: 2161-2129 , 2150-7511
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2011
    detail.hit.zdb_id: 2557172-2
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  • 9
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 202, No. 18 ( 2020-08-25)
    Abstract: Posttranscriptional gene regulation often involves RNA-binding proteins that modulate mRNA translation and/or stability either directly through protein-RNA interactions or indirectly by facilitating the annealing of small regulatory RNAs (sRNAs). The human pathogen Streptococcus pneumoniae D39 (pneumococcus) does not encode homologs to RNA-binding proteins known to be involved in promoting sRNA stability and function, such as Hfq or ProQ, even though it contains genes for at least 112 sRNAs. However, the pneumococcal genome contains genes for other RNA-binding proteins, including at least six S1 domain proteins: ribosomal protein S1 ( rpsA ), polynucleotide phosphorylase ( pnpA ), RNase R ( rnr ), and three proteins with unknown functions. Here, we characterize the function of one of these conserved, yet uncharacterized, S1 domain proteins, SPD_1366, which we have renamed CvfD ( c onserved v irulence f actor D ), since loss of the protein results in attenuation of virulence in a murine pneumonia model. We report that deletion of cvfD impacts the expression of 144 transcripts, including the pst1 operon, encoding phosphate transport system 1 in S. pneumoniae . We further show that CvfD posttranscriptionally regulates the PhoU2 master regulator of the pneumococcal dual-phosphate transport system by binding phoU2 mRNA and impacting PhoU2 translation. CvfD not only controls expression of phosphate transporter genes but also functions as a pleiotropic regulator that impacts cold sensitivity and the expression of sRNAs and genes involved in diverse cellular functions, including manganese uptake and zinc efflux. Together, our data show that CvfD exerts a broad impact on pneumococcal physiology and virulence, partly by posttranscriptional gene regulation. IMPORTANCE Recent advances have led to the identification of numerous sRNAs in the major human respiratory pathogen S. pneumoniae . However, little is known about the functions of most sRNAs or RNA-binding proteins involved in RNA biology in pneumococcus. In this paper, we characterize the phenotypes and one target of the S1 domain RNA-binding protein CvfD, a homolog of general stress protein 13 identified, but not extensively characterized, in other Firmicutes species. Pneumococcal CvfD is a broadly pleiotropic regulator, whose absence results in misregulation of divalent cation homeostasis, reduced translation of the PhoU2 master regulator of phosphate uptake, altered metabolism and sRNA amounts, cold sensitivity, and attenuation of virulence. These findings underscore the critical roles of RNA biology in pneumococcal physiology and virulence.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2020
    detail.hit.zdb_id: 1481988-0
    SSG: 12
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  • 10
    Online Resource
    Online Resource
    American Society for Microbiology ; 2005
    In:  Journal of Bacteriology Vol. 187, No. 21 ( 2005-11), p. 7444-7459
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 187, No. 21 ( 2005-11), p. 7444-7459
    Abstract: The VicRK (YycFG) two-component regulatory system (TCS) is required for virulence of the human respiratory pathogen Streptococcus pneumoniae (pneumococcus). The VicR (YycF) response regulator (RR) is essential through its positive regulation of pcsB , which encodes an extracellular protein that mediates murein biosynthesis. To determine other genes that are regulated by VicR, we performed microarray analyses on a unique Δ vicR deletion mutant, which was constructed by uncoupling regulation of pcsB . Results from these microarray experiments support the idea that the VicR RR exerts strong positive regulation on the transcription of a set of genes encoding important surface proteins, including the PspA virulence factor, two proteins (Spr0096 and Spr1875) containing LysM peptidoglycan-binding domains, and a putative membrane protein (Spr0709) of unknown function. To demonstrate direct regulation, we performed band shift and footprinting experiments using purified unphosphorylated VicR and phosphorylated VicR-P, which was prepared by reaction with acetyl phosphate. VicR and VicR-P bound to regions upstream of pcsB , pspA , spr0096 , spr1875 , and spr0709. Phosphorylation of VicR to VicR-P increased the apparent strength and changed the nature of binding to these regions. DNase I footprinting of VicR and VicR-P bound to regions upstream of pcsB , pspA , spr0096 , and spr1875 showed protection of extended regions containing a degenerate sequence related to a previously proposed consensus. These combined approaches did not support autoregulation of the vicRKX operon or substantive direct regulation of fatty acid biosynthesis by VicR or VicR-P. However, the Δ vicR mutant required fatty acids in some conditions, which supports the notion that the VicRK TCS may mediate membrane integrity as well as murein biosynthesis and virulence factor expression in S. pneumoniae.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2005
    detail.hit.zdb_id: 1481988-0
    SSG: 12
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