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  • 1
    Online Resource
    Online Resource
    IsdC from Staphylococcus lugdunensis Induces Biofilm Formation under Low-Iron Growth Conditions
    American Society for Microbiology ; 2014
    In:  Infection and Immunity Vol. 82, No. 6 ( 2014-06), p. 2448-2459
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 82, No. 6 ( 2014-06), p. 2448-2459
    Abstract: Staphylococcus lugdunensis is a coagulase-negative staphylococcus that is a commensal of humans and an opportunistic pathogen. It can cause a spectrum of infections, including those that are associated with the ability to form biofilm, such as occurs with endocarditis or indwelling medical devices. The genome sequences of two strains revealed the presence of orthologues of the ica genes that are responsible for synthesis of poly- N -acetylglucosamine (PNAG) that is commonly associated with biofilm in other staphylococci. However, we discovered that biofilm formed by a panel of S. lugdunensis isolates growing in iron-restricted medium was susceptible to degradation by proteases and not by metaperiodate, suggesting that the biofilm matrix comprised proteins and not PNAG. When the iron concentration was raised to 1 mM biofilm formation by all strains tested was greatly reduced. A mutant of strain N920143 lacking the entire locus that encodes iron-regulated surface determinant (Isd) proteins was defective in biofilm formation under iron-limited conditions. An IsdC-null mutant was defective, whereas IsdK, IsdJ, and IsdB mutants formed biofilm to the same level as the parental strain. Expression of IsdC was required both for the primary attachment to unconditioned polystyrene and for the accumulation phase of biofilm involving cell-cell interactions. Purified recombinant IsdC protein formed dimers in solution and Lactococcus lactis cells expressing only IsdC adhered to immobilized recombinant IsdC but not to IsdJ, IsdK, or IsdB. This is consistent with a specific homophilic interaction between IsdC molecules on neighboring cells contributing to accumulation of S. lugdunensis biofilm in vivo .
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.01542-14
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2014
    detail.hit.zdb_id: 1483247-1
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  • 2
    Online Resource
    Online Resource
    Fibronectin Binding Proteins SpsD and SpsL Both Support Invasion of Canine Epithelial Cells by Staphylococcus pseudintermedius
    American Society for Microbiology ; 2015
    In:  Infection and Immunity Vol. 83, No. 10 ( 2015-10), p. 4093-4102
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 83, No. 10 ( 2015-10), p. 4093-4102
    Abstract: In this study, we investigated the cell wall-anchored fibronectin-binding proteins SpsD and SpsL from the canine commensal and pathogen Staphylococcus pseudintermedius for their role in promoting bacterial invasion of canine progenitor epidermal keratinocytes (CPEK). Invasion was examined by the gentamicin protection assay and fluorescence microscopy. An Δ spsD ΔspsL mutant of strain ED99 had a dramatically reduced capacity to invade CPEK monolayers, while no difference in the invasion level was observed with single mutants. Lactococcus lactis transformed with plasmids expressing SpsD and SpsL promoted invasion, showing that both proteins are important. Soluble fibronectin was required for invasion, and an RGD-containing peptide or antibodies recognizing the integrin α 5 β 1 markedly reduced invasion, suggesting an important role for the integrin in this process. Src kinase inhibitors effectively blocked internalization, suggesting a functional role for the kinase in invasion. In order to identify the minimal fibronectin-binding region of SpsD and SpsL involved in the internalization process, recombinant fragments of both proteins were produced. The SpsD 520–846 and SpsL 538–823 regions harboring the major fibronectin-binding sites inhibited S. pseudintermedius internalization. Finally, the effects of staphylococcal invasion on the integrity of different cell lines were examined. Because SpsD and SpsL are critical factors for adhesion and invasion, blocking these processes could provide a strategy for future approaches to treating infections.
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.00542-15
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2015
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  • 3
    Online Resource
    Online Resource
    The Sbi Protein Is a Multifunctional Immune Evasion Factor of Staphylococcus aureus
    American Society for Microbiology ; 2011
    In:  Infection and Immunity Vol. 79, No. 9 ( 2011-09), p. 3801-3809
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 79, No. 9 ( 2011-09), p. 3801-3809
    Abstract: The second immunoglobulin-binding protein (Sbi) of Staphylococcus aureus has two N-terminal domains that bind the Fc region of IgG in a fashion similar to that of protein A and two domains that can bind to the complement protein C3 and promote its futile consumption in the fluid phase. It has been proposed that Sbi helps bacteria to avoid innate immune defenses. By comparing a mutant defective in Sbi with mutants defective in protein A, clumping factor A, iron-regulated surface determinant H, and capsular polysaccharide, it was shown that Sbi is indeed an immune evasion factor that promotes bacterial survival in whole human blood and the avoidance of neutrophil-mediated opsonophagocytosis. Sbi is present in the culture supernatant and is also associated with the cell envelope. S. aureus strains that expressed truncates of Sbi lacking N-terminal domains D1 and D2 (D1D2) or D3 and D4 (D3D4) or a C-terminal truncate that was no longer retained in the cell envelope were analyzed. Both the secreted and envelope-associated forms of Sbi contributed to immune evasion. The IgG-binding domains contributed only when Sbi was attached to the cell, while only the secreted C3-binding domains were biologically active.
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.05075-11
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2011
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  • 4
    Online Resource
    Online Resource
    Role of Surface Protein SasG in Biofilm Formation by Staphylococcus aureus
    American Society for Microbiology ; 2010
    In:  Journal of Bacteriology Vol. 192, No. 21 ( 2010-11), p. 5663-5673
    Details
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 192, No. 21 ( 2010-11), p. 5663-5673
    Abstract: The SasG surface protein of Staphylococcus aureus has been shown to promote the formation of biofilm. SasG comprises an N-terminal A domain and repeated B domains. Here we demonstrate that SasG is involved in the accumulation phase of biofilm, a process that requires a physiological concentration of Zn 2+ . The B domains, but not the A domain, are required. Purified recombinant B domain protein can form dimers in vitro in a Zn 2+ -dependent fashion. Furthermore, the protein can bind to cells that have B domains anchored to their surface and block biofilm formation. The full-length SasG protein exposed on the cell surface is processed within the B domains to a limited degree, resulting in cleaved proteins of various lengths being released into the supernatant. Some of the released molecules associate with the surface-exposed B domains that remain attached to the cell. Studies using inhibitors and mutants failed to identify any protease that could cause the observed cleavage within the B domains. Extensively purified recombinant B domain protein is very labile, and we propose that cleavage occurs spontaneously at labile peptide bonds and that this is necessary for biofilm formation.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    URL: Article
    DOI: 10.1128/JB.00628-10
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2010
    detail.hit.zdb_id: 1481988-0
    SSG: 12
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  • 5
    Online Resource
    Online Resource
    Antibody Response to Fibronectin-Binding Adhesin FnbpA in Patients with Staphylococcus aureus Infections
    American Society for Microbiology ; 1998
    In:  Infection and Immunity Vol. 66, No. 11 ( 1998-11), p. 5433-5442
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 66, No. 11 ( 1998-11), p. 5433-5442
    Abstract: We have analyzed antibody reactivity to a fibronectin-binding microbial surface component that recognizes adhesive matrix molecules (MSCRAMM) in blood plasma collected from patients with staphylococcal infections. All patients had elevated levels of anti-MSCRAMM antibodies compared to those of young children who, presumably, had not been exposed to staphylococcal infections. The anti-MSCRAMM antibodies preferentially reacted with the ligand-binding repeat domain of the adhesin. However, these antibodies did not inhibit fibronectin binding. Essentially, all patients had antibodies which specifically recognized the fibronectin-MSCRAMM complex but not the isolated components. Epitopes recognized by these anti-ligand-induced binding sites antibodies were found in each repeat unit of the MSCRAMM. These results demonstrate that staphylococci have bound fibronectin some time during infection and that each repeat unit in the MSCRAMM can engage in ligand binding. Furthermore, our previously proposed model, suggesting that an unordered structure in the MSCRAMM undergoes a conformational change upon ligand binding (K. House-Pompeo, Y. Xu, D. Joh, P. Speziale, and M. Höök, J. Biol. Chem. 271:1379–1384, 1996), is presumably operational in patients during infections.
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.66.11.5433-5442.1998
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1998
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  • 6
    Online Resource
    Online Resource
    SpyAD, a Moonlighting Protein of Group A Streptococcus Contributing to Bacterial Division and Host Cell Adhesion
    American Society for Microbiology ; 2014
    In:  Infection and Immunity Vol. 82, No. 7 ( 2014-07), p. 2890-2901
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 82, No. 7 ( 2014-07), p. 2890-2901
    Abstract: Group A streptococcus (GAS) is a human pathogen causing a wide repertoire of mild and severe diseases for which no vaccine is yet available. We recently reported the identification of three protein antigens that in combination conferred wide protection against GAS infection in mice. Here we focused our attention on the characterization of one of these three antigens, Spy0269, a highly conserved, surface-exposed, and immunogenic protein of unknown function. Deletion of the spy0269 gene in a GAS M1 isolate resulted in very long bacterial chains, which is indicative of an impaired capacity of the knockout mutant to properly divide. Confocal microscopy and immunoprecipitation experiments demonstrated that the protein was mainly localized at the cell septum and could interact in vitro with the cell division protein FtsZ, leading us to hypothesize that Spy0269 is a member of the GAS divisome machinery. Predicted structural domains and sequence homologies with known streptococcal adhesins suggested that this antigen could also play a role in mediating GAS interaction with host cells. This hypothesis was confirmed by showing that recombinant Spy0269 could bind to mammalian epithelial cells in vitro and that Lactococcus lactis expressing Spy0269 on its cell surface could adhere to mammalian cells in vitro and to mice nasal mucosa in vivo . On the basis of these data, we believe that Spy0269 is involved both in bacterial cell division and in adhesion to host cells and we propose to rename this multifunctional moonlighting protein as SpyAD ( S treptococcus py ogenes A dhesion and D ivision protein).
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.00064-14
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2014
    detail.hit.zdb_id: 1483247-1
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