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Streptococcus mutans Proteases Degrade Dentinal Collagen. Dent J (Basel) 2022; 10:dj10120223. [PMID: 36547039 PMCID: PMC9776523 DOI: 10.3390/dj10120223] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/21/2022] [Accepted: 11/24/2022] [Indexed: 11/30/2022] Open
Abstract
Here, we explored the role of S. mutans’s whole cell and discrete fractions in the degradation of type I collagen and dentinal collagen. Type I collagen gels and human demineralized dentin slabs (DS) were incubated in media alone or with one of the following: overnight (O/N) or newly inoculated (NEW) cultures of S. mutans UA159; intracellular proteins, supernatant or bacterial membranes of O/N cultures. Media from all groups were analyzed for protease-mediated release of the collagen-specific imino acid hydroxyproline. Images of type I collagen and DS were analyzed, respectively. Type I collagen degradation was highest for the supernatant (p < 0.05) fractions, followed by intracellular components and O/N cultures. Collagen degradation for DS samples was highest for O/N samples, followed by supernatant, and intracellular components (p < 0.05). There was lower detectable degradation for both type I collagen and DS from NEW culture samples (p < 0.05), and there was no type I collagen or DS degradation detected for bacterial membrane samples. Structural changes to type I collagen gel and dentinal collagen were observed, respectively, following incubation with S. mutans cultures (O/N and NEW), intracellular components, and supernatant. This study demonstrates that intracellular and extracellular proteolytic activities from S. mutans enable this cariogenic bacterium to degrade type I and dentinal collagen in a growth-phase dependent manner, potentially contributing to the progression of dental caries.
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Kim BJ, Hancock BM, Bermudez A, Del Cid N, Reyes E, van Sorge NM, Lauth X, Smurthwaite CA, Hilton BJ, Stotland A, Banerjee A, Buchanan J, Wolkowicz R, Traver D, Doran KS. Bacterial induction of Snail1 contributes to blood-brain barrier disruption. J Clin Invest 2015; 125:2473-83. [PMID: 25961453 DOI: 10.1172/jci74159] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 04/06/2015] [Indexed: 12/23/2022] Open
Abstract
Bacterial meningitis is a serious infection of the CNS that results when blood-borne bacteria are able to cross the blood-brain barrier (BBB). Group B Streptococcus (GBS) is the leading cause of neonatal meningitis; however, the molecular mechanisms that regulate bacterial BBB disruption and penetration are not well understood. Here, we found that infection of human brain microvascular endothelial cells (hBMECs) with GBS and other meningeal pathogens results in the induction of host transcriptional repressor Snail1, which impedes expression of tight junction genes. Moreover, GBS infection also induced Snail1 expression in murine and zebrafish models. Tight junction components ZO-1, claudin 5, and occludin were decreased at both the transcript and protein levels in hBMECs following GBS infection, and this repression was dependent on Snail1 induction. Bacteria-independent Snail1 expression was sufficient to facilitate tight junction disruption, promoting BBB permeability to allow bacterial passage. GBS induction of Snail1 expression was dependent on the ERK1/2/MAPK signaling cascade and bacterial cell wall components. Finally, overexpression of a dominant-negative Snail1 homolog in zebrafish elevated transcription of tight junction protein-encoding genes and increased zebrafish survival in response to GBS challenge. Taken together, our data support a Snail1-dependent mechanism of BBB disruption and penetration by meningeal pathogens.
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Cozzi R, Malito E, Nuccitelli A, D'Onofrio M, Martinelli M, Ferlenghi I, Grandi G, Telford JL, Maione D, Rinaudo CD. Structure analysis and site-directed mutagenesis of defined key residues and motives for pilus-related sortase C1 in group B Streptococcus. FASEB J 2011; 25:1874-86. [PMID: 21357525 DOI: 10.1096/fj.10-174797] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In group B Streptococcus (GBS), 3 structurally distinct types of pili have been discovered as potential virulence factors and vaccine candidates. The pilus-forming proteins are assembled into high-molecular-weight polymers via a transpeptidation mechanism mediated by specific class C sortases. Using a multidisciplinary approach including bioinformatics, structural and biochemical studies, and in vivo mutagenesis, we performed a broad characterization of GBS sortase C1 of pilus island 2a. The high-resolution X-ray structure of the enzyme revealed that the active site, into the β-barrel core of the enzyme, is made of the catalytic triad His157-Cys219-Arg228 and covered by a loop, known as the "lid." We show that the catalytic triad and the predicted N- and C-terminal transmembrane regions are required for the enzyme activity. Interestingly, by in vivo complementation mutagenesis studies, we found that the deletion of the entire lid loop or mutations in specific lid key residues had no effect on catalytic activity of the enzyme. In addition, kinetic characterizations of recombinant enzymes indicate that the lid mutants can still recognize and cleave the substrate-mimicking peptide at least as well as the wild-type protein.
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Affiliation(s)
- Roberta Cozzi
- Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy
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Al Safadi R, Amor S, Hery-Arnaud G, Spellerberg B, Lanotte P, Mereghetti L, Gannier F, Quentin R, Rosenau A. Enhanced expression of lmb gene encoding laminin-binding protein in Streptococcus agalactiae strains harboring IS1548 in scpB-lmb intergenic region. PLoS One 2010; 5:e10794. [PMID: 20520730 PMCID: PMC2875397 DOI: 10.1371/journal.pone.0010794] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 05/01/2010] [Indexed: 11/19/2022] Open
Abstract
Group B streptococcus (GBS) is the main cause of neonatal sepsis and meningitis. Bacterial surface proteins play a major role in GBS binding to and invasion of different host surfaces. The scpB and lmb genes, coding for fibronectin-binding and laminin-binding surface proteins, are present in almost all human GBS isolates. The scpB-lmb intergenic region is a hot spot for integration of two mobile genetic elements (MGEs): the insertion element IS1548 or the group II intron GBSi1. We studied the structure of scpB-lmb intergenic region in 111 GBS isolates belonging to the intraspecies major clonal complexes (CCs). IS1548 was mostly found (72.2%) in CC19 serotype III strains recovered more specifically (92.3%) from neonatal meningitis. GBSi1 was principally found (70.6%) in CC17 strains, mostly (94.4%) of serotype III, but also (15.7%) in CC19 strains, mostly (87.5%) of serotype II. No MGE was found in most strains of the other CCs (76.0%), notably CC23, CC10 and CC1. Twenty-six strains representing these three genetic configurations were selected to investigate the transcription and expression levels of scpB and lmb genes. Quantitative RT-PCR showed that lmb transcripts were 5.0- to 9.6-fold higher in the group of strains with IS1548 than in the other two groups of strains (P<0.001). Accordingly, the binding ability to laminin was 3.8- to 6.6-fold higher in these strains (P≤0.001). Moreover, Lmb amount expressed on the cell surface was 2.4- to 2.7-fold greater in these strains (P<0.001). By contrast, scpB transcript levels and fibronectin binding ability were similar in the three groups of strains. Deletion of the IS1548 sequence between scpB and lmb genes in a CC19 serotype III GBS strain substantially reduced the transcription of lmb gene (13.5-fold), the binding ability to laminin (6.2-fold), and the expression of Lmb protein (5.0-fold). These data highlight the importance of MGEs in bacterial virulence and demonstrate the up-regulation of lmb gene by IS1548; the increased lmb gene expression observed in CC19 serotype III strains with IS1548 may play a role in their ability to cause neonatal meningitis and endocarditis.
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Affiliation(s)
- Rim Al Safadi
- Equipe d'Accueil 3854 Bactéries et Risque Materno-Fœtal, Institut Fédératif de Recherche 136 Agents Transmissibles et Infectiologie, UFR Médecine, Université François Rabelais de Tours, Tours, France
| | - Souheila Amor
- Equipe d'Accueil 3854 Bactéries et Risque Materno-Fœtal, Institut Fédératif de Recherche 136 Agents Transmissibles et Infectiologie, UFR Médecine, Université François Rabelais de Tours, Tours, France
| | - Geneviève Hery-Arnaud
- Equipe d'Accueil 3854 Bactéries et Risque Materno-Fœtal, Institut Fédératif de Recherche 136 Agents Transmissibles et Infectiologie, UFR Médecine, Université François Rabelais de Tours, Tours, France
| | - Barbara Spellerberg
- Institut für Medizinische Mikrobiologie und Hygiene, Universitäsklinikum Ulm, Ulm, Germany
| | - Philippe Lanotte
- Equipe d'Accueil 3854 Bactéries et Risque Materno-Fœtal, Institut Fédératif de Recherche 136 Agents Transmissibles et Infectiologie, UFR Médecine, Université François Rabelais de Tours, Tours, France
| | - Laurent Mereghetti
- Equipe d'Accueil 3854 Bactéries et Risque Materno-Fœtal, Institut Fédératif de Recherche 136 Agents Transmissibles et Infectiologie, UFR Médecine, Université François Rabelais de Tours, Tours, France
| | - François Gannier
- Unité Mixte de Recherche CNRS FRE 3092 Physiologie des Cellules Cardiaques et Vasculaires, UFR Sciences, Université François Rabelais de Tours, Tours, France
| | - Roland Quentin
- Equipe d'Accueil 3854 Bactéries et Risque Materno-Fœtal, Institut Fédératif de Recherche 136 Agents Transmissibles et Infectiologie, UFR Médecine, Université François Rabelais de Tours, Tours, France
- Service de Bactériologie et Hygiène Hospitalière, Hôpital Trousseau, CHRU de Tours, Tours, France
| | - Agnès Rosenau
- Equipe d'Accueil 3854 Bactéries et Risque Materno-Fœtal, Institut Fédératif de Recherche 136 Agents Transmissibles et Infectiologie, UFR Médecine, Université François Rabelais de Tours, Tours, France
- * E-mail:
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Lactic acid is a potential virulence factor for group B Streptococcus. Microb Pathog 2009; 46:43-52. [DOI: 10.1016/j.micpath.2008.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 10/07/2008] [Accepted: 10/17/2008] [Indexed: 11/22/2022]
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6
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Hasona A, Zuobi-Hasona K, Crowley PJ, Abranches J, Ruelf MA, Bleiweis AS, Brady LJ. Membrane composition changes and physiological adaptation by Streptococcus mutans signal recognition particle pathway mutants. J Bacteriol 2006; 189:1219-30. [PMID: 17085548 PMCID: PMC1797365 DOI: 10.1128/jb.01146-06] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Previously, we presented evidence that the oral cariogenic species Streptococcus mutans remains viable but physiologically impaired and sensitive to environmental stress when genes encoding the minimal conserved bacterial signal recognition particle (SRP) elements are inactivated. Two-dimensional gel electrophoresis of isolated membrane fractions from strain UA159 and three mutants (Deltaffh, DeltascRNA, and DeltaftsY) grown at pH 7.0 or pH 5.0 allowed us to obtain insight into the adaptation process and the identities of potential SRP substrates. Mutant membrane preparations contained increased amounts of the chaperones DnaK and GroES and ClpP protease but decreased amounts of transcription- and translation-related proteins, the beta subunit of ATPase, HPr, and several metabolic and glycolytic enzymes. Therefore, the acid sensitivity of SRP mutants might be caused in part by diminished ATPase activity, as well as the absence of an efficient mechanism for supplying ATP quickly at the site of proton elimination. Decreased amounts of LuxS were also observed in all mutant membranes. To further define physiological changes that occur upon disruption of the SRP pathway, we studied global gene expression in S. mutans UA159 (parent strain) and AH333 (Deltaffh mutant) using microarray analysis. Transcriptome analysis revealed up-regulation of 81 genes, including genes encoding chaperones, proteases, cell envelope biosynthetic enzymes, and DNA repair and replication enzymes, and down-regulation of 35 genes, including genes concerned with competence, ribosomal proteins, and enzymes involved in amino acid and protein biosynthesis. Quantitative real-time reverse transcription-PCR analysis of eight selected genes confirmed the microarray data. Consistent with a demonstrated defect in competence and the suggested impairment of LuxS-dependent quorum sensing, biofilm formation was significantly decreased in each SRP mutant.
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Affiliation(s)
- Adnan Hasona
- Department of Oral Biology, University of Florida, Gainesville, FL 32610, USA.
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7
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Gottschalk B, Bröker G, Kuhn M, Aymanns S, Gleich-Theurer U, Spellerberg B. Transport of multidrug resistance substrates by the Streptococcus agalactiae hemolysin transporter. J Bacteriol 2006; 188:5984-92. [PMID: 16885467 PMCID: PMC1540086 DOI: 10.1128/jb.00768-05] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus agalactiae (group B streptococcus [GBS]) causes neonatal sepsis, pneumonia, and meningitis, as well as infections of the bovine udder. The S. agalactiae hemolysin is regarded as an important virulence factor, and hemolysin expression is dependent on the cyl gene cluster. cylA and cylB encode the ATP binding and transmembrane domains of a typical ATP binding cassette (ABC) transporter. The deduced proteins contain the signature sequence of a multidrug resistance (MDR) transporter, and mutation of the genes results in a nonhemolytic and nonpigmented phenotype. To further elucidate the function of the putative transporter, nonpolar deletion mutants of cylA were constructed. These mutants are nonhemolytic and can be complemented by the transporter genes. Wild-type strain and nonhemolytic cylA and cylK deletion mutants were exposed to known substrates of MDR transporters. Mutation of cylA significantly impaired growth in the presence of daunorubicin, doxorubicin, and rhodamine 6G and resulted in a decreased export of doxorubicin from the cells. The mutation of cylK, a gene of unknown function located downstream from cylA, caused a loss of hemolysis but had no effect on the transport of MDR substrates. Furthermore, the hemolytic activity of the wild-type strain was inhibited by reserpine in a dose-dependent manner. We conclude that CylAB closely resembles an ABC-type MDR transporter and propose that the GBS hemolysin molecule represents a natural substrate of the transporter.
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Affiliation(s)
- Birgit Gottschalk
- Department of Medical Microbiology and Hygiene, University of Ulm, Robert Koch Str. 8, D-89081 Ulm, Germany
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Bergonzelli GE, Granato D, Pridmore RD, Marvin-Guy LF, Donnicola D, Corthésy-Theulaz IE. GroEL of Lactobacillus johnsonii La1 (NCC 533) is cell surface associated: potential role in interactions with the host and the gastric pathogen Helicobacter pylori. Infect Immun 2006; 74:425-34. [PMID: 16368998 PMCID: PMC1346591 DOI: 10.1128/iai.74.1.425-434.2006] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Revised: 05/31/2005] [Accepted: 10/13/2005] [Indexed: 11/20/2022] Open
Abstract
Heat shock proteins of the GroEL or Hsp60 class are highly conserved proteins essential to all living organisms. Even though GroEL proteins are classically considered intracellular proteins, they have been found at the surface of several mucosal pathogens and have been implicated in cell attachment and immune modulation. The purpose of the present study was to investigate the GroEL protein of a gram-positive probiotic bacterium, Lactobacillus johnsonii La1 (NCC 533). Its presence at the bacterial surface was demonstrated using a whole-cell enzyme-linked immunosorbent assay and could be detected in bacterial spent culture medium by immunoblotting. To assess binding of La1 GroEL to mucins and intestinal epithelial cells, the La1 GroEL protein was expressed in Escherichia coli. We report here that La1 recombinant GroEL (rGroEL) binds to mucins and epithelial cells and that this binding is pH dependent. Immunomodulation studies showed that La1 rGroEL stimulates interleukin-8 secretion in macrophages and HT29 cells in a CD14-dependent mechanism. This property is common to rGroEL from other gram-positive bacteria but not to the rGroEL of the gastric pathogen Helicobacter pylori. In addition, La1 rGroEL mediates the aggregation of H. pylori but not that of other intestinal pathogens. Our in vitro results suggest that GroEL proteins from La1 and other lactic acid bacteria might play a role in gastrointestinal homeostasis due to their ability to bind to components of the gastrointestinal mucosa and to aggregate H. pylori.
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Ge J, Catt DM, Gregory RL. Streptococcus mutans surface alpha-enolase binds salivary mucin MG2 and human plasminogen. Infect Immun 2004; 72:6748-52. [PMID: 15501816 PMCID: PMC523000 DOI: 10.1128/iai.72.11.6748-6752.2004] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis identified enolase as a cell surface component of Streptococcus mutans, which was confirmed by enzyme-linked immunosorbent assay, Western blotting, and transmission electron microscopy. Surface enolase was demonstrated to bind to human plasminogen and salivary mucin MG2. The results suggested a role for enolase in S. mutans attachment, clearance, or breach of the bloodstream barrier.
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Affiliation(s)
- Jingping Ge
- Department of Pathology and Laboratory Medicine, School of Medicine, Indiana University, Indianapolis, USA
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10
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McMillan DJ, Davies MR, Good MF, Sriprakash KS. Immune response to superoxide dismutase in group A streptococcal infection. ACTA ACUST UNITED AC 2004; 40:249-56. [PMID: 15039102 DOI: 10.1016/s0928-8244(04)00003-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Revised: 12/16/2003] [Accepted: 12/24/2003] [Indexed: 11/30/2022]
Abstract
Extracellular localisation of manganese-dependent superoxide dismutase (SodA) by group A streptococcus (GAS) may have a role in protection of this pathogenic bacterium from exogenously produced reactive oxygen species. In this study we show that SodA is found both in surface protein extracts and in culture supernatants of GAS. To investigate whether SodA is a possible vaccine candidate outbred Quackenbush mice were subcutaneously vaccinated with recombinant SodA. Strong antibody responses which were moderately opsonic were elicited. These antibodies were unable to protect mice from intraperitoneal challenge with M1 GAS. We also show that SodA and p145 (a conserved peptide from the M-protein) antibodies are present at significantly higher levels amongst patients with rheumatic heart disease than in control subjects from the same endemic region. The higher SodA antibody levels in patients may be indicative of a role for this protein in pathogenesis of rheumatic heart disease but are more likely to be a marker of recent or recurrent streptococcal infection.
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Affiliation(s)
- David J McMillan
- The Queensland Institute of Medical Research, Brisbane, QLD, Australia.
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Granato D, Bergonzelli GE, Pridmore RD, Marvin L, Rouvet M, Corthésy-Theulaz IE. Cell surface-associated elongation factor Tu mediates the attachment of Lactobacillus johnsonii NCC533 (La1) to human intestinal cells and mucins. Infect Immun 2004; 72:2160-9. [PMID: 15039339 PMCID: PMC375183 DOI: 10.1128/iai.72.4.2160-2169.2004] [Citation(s) in RCA: 286] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this work was to identify Lactobacillus johnsonii NCC533 (La1) surface molecules mediating attachment to intestinal epithelial cells and mucins. Incubation of Caco-2 intestinal epithelial cells with an L. johnsonii La1 cell wall extract led to the recognition of elongation factor Tu (EF-Tu) as a novel La1 adhesin-like factor. The presence of EF-Tu at the surface of La1 was confirmed by analysis of purified outer surface protein extract by immunoblotting experiments, by electron microscopy, and by enzyme-linked immunosorbent assays of live bacteria. Furthermore, tandem mass spectrometry analysis proved that EF-TU was expressed at the La1 surface as an intact molecule. Using recombinant La1 EF-Tu protein, we were able to determine that its binding to intestinal cells and to mucins is pH dependent. Competition experiments suggested that EF-Tu has an important role in La1 mucin binding capacity. In addition, immunomodulation studies performed on HT29 cells showed that EF-Tu recombinant protein can induce a proinflammatory response in the presence of soluble CD14. Our in vitro results indicate that EF-Tu, through its binding to the intestinal mucosa, might participate in gut homeostasis.
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Takamatsu D, Bensing BA, Sullam PM. Genes in the accessory sec locus of Streptococcus gordonii have three functionally distinct effects on the expression of the platelet-binding protein GspB. Mol Microbiol 2004; 52:189-203. [PMID: 15049820 DOI: 10.1111/j.1365-2958.2004.03978.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Platelet binding by Streptococcus gordonii strain M99 is strongly correlated with the expression of the large surface glycoprotein GspB. A 14 kb chromosomal region downstream of gspB was previously shown to be required for the expression of this protein. The region encodes SecA2 and SecY2, which are components of an accessory secretion system dedicated specifically to the export of GspB. The region also includes three genes (gly, nss and gtf) that encode proteins likely to function in carbohydrate metabolism, and four genes (orf1-4) that encode proteins of unknown function. In this report, we have investigated the role of these genes in GspB expression. We found that disruption of orf1, orf2 or orf3 resulted in a loss of GspB export and the intracellular accumulation of GspB. As they are apparently essential components of the accessory secretion system, these genes were renamed asp1-3 (for accessory secretory protein). In gtf and orf4 mutants, gspB was transcribed, but no GspB was detected. These results suggest that Gtf and Orf4 are required for the translation or for the stability of GspB. In contrast, gly and nss mutants were able to express and export GspB. However, disruption of these genes appeared to affect the carbohydrate composition of this glycoprotein. As asp1-3, gtf and orf4, but not gly and nss, are conserved in the accessory sec loci of several staphylococcal and streptococcal species, these genes may also have crucial roles in the expression and export of GspB homologues in the other Gram-positive bacteria.
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Affiliation(s)
- Daisuke Takamatsu
- Division of Infectious Diseases, Veterans Affairs Medical Center (111W) and the University of California, 4150 Clement Street, San Francisco, CA 94121, USA
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Fontaine MC, Perez-Casal J, Willson PJ. Investigation of a novel DNase of Streptococcus suis serotype 2. Infect Immun 2004; 72:774-81. [PMID: 14742520 PMCID: PMC321577 DOI: 10.1128/iai.72.2.774-781.2004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A secreted nuclease, SsnA, was identified in the virulent Streptococcus suis isolate SX332 and subsequently in each of the type strains of capsular serotypes 1 through 9. Screening of 258 porcine clinical isolates from surface (nasal mucosa or palatine tonsil) or internal (joint, brain or other internal organ) locations revealed a significant relationship (P < 0.001) between expression of nuclease and isolation from an internal site. A 3,126-bp gene, ssnA, was identified from a phenotypically nuclease-negative pGh9:ISS1 insertion mutant, and analysis of the predicted SsnA sequence revealed a 35-amino-acid (aa) secretion signal sequence, a 22-aa DNA-binding domain, and a typical gram-positive cell wall sorting motif. A requirement of Ca2+ and Mg2+ for SsnA activity was determined, and the substrate specificity was found to be for single- and double-stranded linear DNA. Reverse transcription-PCR experiments revealed that ssnA is expressed throughout all stages of S. suis growth, and Western blots with porcine anti-S. suis immune sera against a recombinant, truncated SsnA derivative (rSsnADelta) confirmed that SsnA is expressed in vivo. Furthermore, anti-rSsnADelta antibodies were sufficient to neutralize SsnA activity. Analyses of subcellular fractions of SX332 and derived mutants, on DNA-containing polyacrylamide gels and by Western blotting, suggest that SsnA is cell wall located.
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Affiliation(s)
- Michael C Fontaine
- Vaccine & Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E3, Canada
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Hughes MJG, Wilson R, Moore JC, Lane JD, Dobson RJ, Muckett P, Younes Z, Pribul P, Topping A, Feldman RG, Santangelo JD. Novel protein vaccine candidates against Group B streptococcal infection identified using alkaline phosphatase fusions. FEMS Microbiol Lett 2003; 222:263-71. [PMID: 12770717 DOI: 10.1016/s0378-1097(03)00310-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Using an alkaline phosphatase-based genetic screening method, we identified a number of proteins that are potentially located on the outer surface of Group B streptococcus (Streptococcus agalactiae). In an enzyme-linked immunosorbent assay, antisera raised against two of the proteins, the streptococcal yutD homologue and a subunit of an ABC transporter, recognised clinically important serotypes of Group B streptococcus. In a neonatal rat model, purified IgG from the sera conferred significant levels of protection against a lethal challenge infection. The proteins identified show potential as protein subunit candidates for vaccines against Group B streptococcal disease in neonates.
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Affiliation(s)
- Martin J G Hughes
- Microscience Ltd., 545 Eskdale Road, Winnersh Triangle, Berks RG41 5TU, Wokingham, UK
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15
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Reinscheid DJ, Ehlert K, Chhatwal GS, Eikmanns BJ. Functional analysis of a PcsB-deficient mutant of group B streptococcus. FEMS Microbiol Lett 2003; 221:73-9. [PMID: 12694913 DOI: 10.1016/s0378-1097(03)00167-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Group B streptococcus (GBS) is the major cause of bacterial sepsis and meningitis in neonates and poses a significant threat to parturient women. Recently, we identified in GBS the polypeptide PcsB, which is a protein required for cell separation of GBS, and which is also involved in the antibiotic sensitivity of these bacteria. In the present study, the introduction of the pcsB-carrying plasmid pATpcsB into the PcsB-deficient GBS mutant Sep1 restored the phenotype and the antibiotic susceptibility of this strain to that of the GBS wild-type. Although Northern blots revealed a four- to five-fold increased transcription of pcsB in pATpcsB-carrying GBS strains, overexpression of pcsB did not result in higher amounts of PcsB in the cell wall and in the culture supernatant of GBS, indicating regulatory mechanisms that control the translation or secretion of PcsB in these bacteria. In the culture supernatant of mutant Sep1 significant amounts of enolase were identified. As this protein was also present in extracts of cell wall-bound proteins from the GBS wild-type, it can be speculated that GBS can translocate enolase across the cytoplasmic membrane. Northern blot analysis exhibited similar expression of the enolase gene in the GBS strains 6313 and Sep1, indicating that mutant Sep1 is impaired in the anchoring of this protein to its cell wall.
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Affiliation(s)
- Dieter J Reinscheid
- Department of Microbiology and Biotechnology, University of Ulm, D-89069 Ulm, Germany.
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Reinscheid DJ, Stößer C, Ehlert K, Jack RW, Möller K, Eikmanns BJ, Chhatwal GS. Influence of proteins Bsp and FemH on cell shape and peptidoglycan composition in group B streptococcus. MICROBIOLOGY (READING, ENGLAND) 2002; 148:3245-3254. [PMID: 12368458 DOI: 10.1099/00221287-148-10-3245] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Group B streptococcus (GBS) is surrounded by a capsule. However, little is known about peptidoglycan metabolism in these bacteria. In the present study, a 65 kDa protein was isolated from the culture supernatant of GBS and N-terminally sequenced, permitting isolation of the corresponding gene, termed bsp. The bsp gene was located close to another gene, designated femH, and reverse transcription-PCR revealed a bicistronic transcriptional organization for both genes. The Bsp protein was detected in the culture supernatant from 31 tested clinical isolates of GBS, suggesting a wide distribution of Bsp in these bacteria. Overexpression of bsp resulted in lens-shaped GBS cells, indicating a role for bsp in controlling cell morphology. Insertional disruption of femH resulted in a reduction of the L-alanine content of the peptidoglycan, suggesting that femH is involved in the incorporation of L-alanine residues in the interpeptide chain of the peptidoglycan of GBS.
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Affiliation(s)
- Dieter J Reinscheid
- Department of Microbiology, GBF-National Research Centre for Biotechnology,D-38124 Braunschweig, Germany2
- Department of Microbiology and Biotechnology, University of Ulm, D-89069 Ulm, Germany1
| | - Claudia Stößer
- Department of Microbiology and Biotechnology, University of Ulm, D-89069 Ulm, Germany1
| | - Kerstin Ehlert
- Bayer AG, PH Research Antiinfectives I, D-42096 Wuppertal, Germany3
| | - Ralph W Jack
- Institute for Organic Chemistry, University of Tübingen, D-72070 Tübingen, Germany4
| | - Kerstin Möller
- Department of Microbiology, GBF-National Research Centre for Biotechnology,D-38124 Braunschweig, Germany2
| | - Bernhard J Eikmanns
- Department of Microbiology and Biotechnology, University of Ulm, D-89069 Ulm, Germany1
| | - Gursharan S Chhatwal
- Department of Microbiology, GBF-National Research Centre for Biotechnology,D-38124 Braunschweig, Germany2
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17
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Song XM, Perez-Casal J, Fontaine MC, Potter AA. Bovine immunoglobulin A (IgA)-binding activities of the surface-expressed Mig protein of Streptococcus dysgalactiae. MICROBIOLOGY (READING, ENGLAND) 2002; 148:2055-2064. [PMID: 12101294 DOI: 10.1099/00221287-148-7-2055] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Mig protein of Streptococcus dysgalactiae is a type III immunoglobulin G (IgG)-binding protein, expressing IgG- and alpha2-macroglobulin (alpha2-M)-binding receptors. This study showed that the Mig protein also displays binding activities to bovine immunoglobulin A (B-IgA). Biotin-labelled bovine serum IgA bound immobilized recombinant Mig and alpha2-M receptors derived from Mig, as well as the native Mig extracted from the surface of S. dysgalactiae strain SDG8 and the alpha(2)-M receptor released from the isogenic mig mutant strain Mig8-Mt, as determined by Western blotting and ELISA. There was no B-IgA binding activity to the immobilized IgG receptor derived from Mig or the proteins in the culture supernatant from the mig mutant strain Mig7-Mt, in which expression of Mig or Mig-related peptides on the cell surface was completely abolished. In a reciprocal experiment, biotin-labelled Mig was found to bind immobilized bovine serum IgA but not human IgA (H-IgA). The binding of Mig to bovine serum IgA was competitively inhibited by unlabelled Mig, intact and truncated alpha(2)-M receptors, and bovine serum IgA, but not by the Mig-IgG receptor, H-IgA or B-IgG. The binding of Mig and partially purified bovine secretory IgA (B-sIgA) was also characterized by Western blotting. Membrane-immobilized B-sIgA did not react with the biotin-labelled Mig, whereas soluble B-sIgA showed binding activity to the immobilized alpha2-M receptor of Mig. It is therefore concluded that the 11 kDa N-terminal region of the alpha2-M receptor of the S. dysgalactiae Mig protein specifically binds soluble and immobilized bovine serum IgA, as well as soluble B-sIgA. This is believed to be the first report of a B-IgA-binding protein in S. dysgalactiae.
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Affiliation(s)
- Xin-Ming Song
- Veterinary Infectious Disease Organization (VIDO), Saskatoon, Saskatchewan, Canada S7N 5E31
| | - Jose Perez-Casal
- Veterinary Infectious Disease Organization (VIDO), Saskatoon, Saskatchewan, Canada S7N 5E31
| | - Michael C Fontaine
- Veterinary Infectious Disease Organization (VIDO), Saskatoon, Saskatchewan, Canada S7N 5E31
| | - Andrew A Potter
- Canadian Bacterial Diseases Network, Calgary, Alberta, Canada2
- Veterinary Infectious Disease Organization (VIDO), Saskatoon, Saskatchewan, Canada S7N 5E31
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18
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Hughes MJG, Moore JC, Lane JD, Wilson R, Pribul PK, Younes ZN, Dobson RJ, Everest P, Reason AJ, Redfern JM, Greer FM, Paxton T, Panico M, Morris HR, Feldman RG, Santangelo JD. Identification of major outer surface proteins of Streptococcus agalactiae. Infect Immun 2002; 70:1254-9. [PMID: 11854208 PMCID: PMC127763 DOI: 10.1128/iai.70.3.1254-1259.2002] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2001] [Revised: 09/25/2001] [Accepted: 12/04/2001] [Indexed: 11/20/2022] Open
Abstract
To identify the major outer surface proteins of Streptococcus agalactiae (group B streptococcus), a proteomic analysis was undertaken. An extract of the outer surface proteins was separated by two-dimensional electrophoresis. The visualized spots were identified through a combination of peptide sequencing and reverse genetic methodologies. Of the 30 major spots identified as S. agalactiae specific, 27 have been identified. Six of these proteins, previously unidentified in S. agalactiae, were sequenced and cloned. These were ornithine carbamoyltransferase, phosphoglycerate kinase, nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase, purine nucleoside phosphorylase, enolase, and glucose-6-phosphate isomerase. Using a gram-positive expression system, we have overexpressed two of these proteins in an in vitro system. These recombinant, purified proteins were used to raise antisera. The identification of these proteins as residing on the outer surface was confirmed by the ability of the antisera to react against whole, live bacteria. Further, in a neonatal-animal model system, we demonstrate that some of these sera are protective against lethal doses of bacteria. These studies demonstrate the successful application of proteomics as a technique for identifying vaccine candidates.
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Song XM, Perez-Casal J, Bolton A, Potter AA. Surface-expressed mig protein protects Streptococcus dysgalactiae against phagocytosis by bovine neutrophils. Infect Immun 2001; 69:6030-7. [PMID: 11553540 PMCID: PMC98731 DOI: 10.1128/iai.69.10.6030-6037.2001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mig gene of Streptococcus dysgalactiae, a major bovine mastitis pathogen, encodes two plasma protein-binding receptors, alpha2-macroglobulin (alpha2-M) and immunoglobulin G (IgG). In this study, the mig gene from one S. dysgalactiae isolate was cloned and expressed in Escherichia coli. The IgG receptor region encoded by mig was conserved in 16 S. dysgalactiae strains. An isogenic mig mutant was constructed by allele replacement mutagenesis of the wild-type gene in S. dysgalactiae. The IgG-binding activity was lost in the mig mutant strain, whereas the alpha2-M receptor activity was still expressed but was detected only in the culture supernatant. In flow cytometry phagocytosis and bacterial-colony-counting bactericidal assays, the wild-type strain was found to be significantly more resistant to phagocytosis and killing by bovine neutrophils (PMNs) than the mig mutant strain when bacteria were preincubated with bovine serum. We therefore speculate that the Mig protein of S. dysgalactiae plays a role in virulence of the bacteria by binding to the plasma protein alpha2-M or IgG and thus preventing phagocytosis by bovine PMNs.
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Affiliation(s)
- X M Song
- Veterinary Infectious Disease Organization, Saskatoon, Saskatchewan, Canada
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Moore JC, Muckett PJ, Hughes MJ. Age-dependent presence of antibodies in rat dams, capable of conferring protection against group B Streptococcus infection in neonates. FEMS Microbiol Lett 2001; 202:125-7. [PMID: 11506919 DOI: 10.1111/j.1574-6968.2001.tb10791.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
A rat model was used to investigate maternal age-dependent resistance on group B Streptococcus (GBS)-induced mortality of the offspring. Offspring from young (first time) or older (repeat litters) dams were challenged with GBS. There was an approximate log difference in the dose of GBS required to cause identical levels of mortality in the two groups. The sera of the dams from both groups were analysed by whole-cell ELISA, and it was demonstrated that sera from the older dams possessed circulating IgG cross-reactive to GBS. Since IgG is transplacentally transferred, we conclude that this is the method of observed protection.
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