Staphylococcus pseudintermedius is the major cause of the common canine skin disease, pyoderma, and is a zoonotic pathogen of humans. Multidrug resistant strains of S. pseudintermedius have emerged and are spreading globally leading to decreased therapeutic success. The development of novel therapeutics is hindered by the lack of understanding of critical host-pathogen interactions mediating S. pseudintermedius colonization and pathogenesis. For the major human pathogen Staphylococcus aureus, interactions with host fibrinogen play a fundamental role in pathogenesis. The aim of the current study was to genetically and functionally characterise 2 cell wall-associated proteins of S. pseudintermedius, SpsD and SpsL, which mediate binding to multiple host extracellular matrix proteins including fibrinogen and fibronectin. DNA sequencing of the A- (ligand binding) domains of spsD and spsL genes for 37 phylogenetically diverse isolates revealed a highly conserved sequence for SpsL (97.1% derived amino acid identity), in contrast to more extensive variation for SpsD (76.7% derived amino acid identity). Further, recombination events were identified to have contributed to the evolution of spsD diversity. Functional analysis with gene deletion mutants of S. pseudintermedius strain ED99, constructed in the current study, demonstrated that SpsL is a major cell wall-associated fibrinogen-binding protein with enhanced affinity for canine fibrinogen. Using recombinant chains of fibrinogen it was determined that SpsL binds to the α-chain of fibrinogen similar to clumping factor B (ClfB) of S. aureus. However, ELISA and surface plasmon resonance analyses of recombinant truncated derivatives of SpsL indicated that the predicted ligand-binding N2N3 subdomains of the A-domain of SpsL are not sufficient for high-affinity fibrinogen-binding suggesting that either additional domains or post-translational modifications are required for fibrinogen-binding. Furthermore, development of a murine skin infection model allowed an investigation of the contribution of SpsD and SpsL to pathogenesis revealing a role for SpsL in focal abscess pathology. Overall these studies have provided new insights into the diversity, function and therapeutic potential of S. pseudintermedius fibrinogen-binding proteins.

<p>Staphylococcus aureus is an important human and animal pathogen that causes a wide range of infections. These infections can be very serious and sometimes hard to get rid of, because of the many virulence factors the bacteria produce during infections.</p><p>This project was a research of the extracellular fibrinogen-binding protein, Efb, which is a 15.9 kDa protein that has been shown to be an important virulence factor during S. aureus infections.</p><p>The purpose with the project was to find out if the protein has more than one binding site to fibrinogen and if people produce antibodies against Efb.</p><p>This was performed with methods such as affinity chromatography, ELISA, coagulation test and western blot. It was shown that Efb has two binding sites to fibrinogen. One is placed on the C-terminal part of Efb and the other on the N-terminal. It was also shown that the production of antibodies against Efb rises significantly in people during an ongoing infection.</p>

Staphylococcus aureus is an important human and animal pathogen that causes a wide range of infections. These infections can be very serious and sometimes hard to get rid of, because of the many virulence factors the bacteria produce during infections. This project was a research of the extracellular fibrinogen-binding protein, Efb, which is a 15.9 kDa protein that has been shown to be an important virulence factor during S. aureus infections. The purpose with the project was to find out if the protein has more than one binding site to fibrinogen and if people produce antibodies against Efb. This was performed with methods such as affinity chromatography, ELISA, coagulation test and western blot. It was shown that Efb has two binding sites to fibrinogen. One is placed on the C-terminal part of Efb and the other on the N-terminal. It was also shown that the production of antibodies against Efb rises significantly in people during an ongoing infection.

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 34-38). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 275-317).

Thesis (Ph. D.)--University of Hong Kong, 1998. / Includes bibliographical references (leaves 282-293).

Thesis (M.S.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 57 pages. Includes Vita. Includes bibliographical references.

Zugl.: Leipzig, Universiẗat, Diss., 2005.

This study is focused on characterization of fibrinogen-related proteins (FREPs) from the tick Ixodes ricinus using molecular methods - PCR, cloning, qRT-PCR, RNA interference via dsRNA synthesis and injection, and also pathogen (Borrelia sp.) transmission on animal model.

Made available in DSpace on 2016-09-27T13:40:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-07. Added 1 bitstream(s) on 2016-09-27T13:45:13Z : No. of bitstreams: 1 000870494.pdf: 357411 bytes, checksum: 81c0f3a5e7fdf7f51bc9273bb80f7b8d (MD5) / The D-dimers are the smallest fragments of fibrin degradation products and are produced by plasmin after lysis of fibrin cross-connection. Thus, the objectives of this study were to determine plasma concentrations of D-dimer and fibrinogen in newborn calves and postpartum cows and to compare plasma concentrations of this hemostatic marker between these two groups. Significant increases in plasma concentrations of D-dimers occur during inflammatory processes (such as peritonitis, sepsis), disseminated intravascular coagulation and vena cava thrombosis for example. Plasma concentrations of D-dimer and fibrinogen were not different between groups. There was a significant positive correlation between plasma fibrinogen concentrations between groups. There was no correlation between plasma D-dimer between groups. Therefore, it was possible to establish reference intervals for plasma concentrations of D-dimer in postpartum cows and their newborn calves.