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  • 1
    Language: English
    In: Infection and immunity, February 2009, Vol.77(2), pp.657-66
    Description: Resisting the bactericidal activity of naturally occurring antibodies and complement of normal human serum is an important element in the evasion of innate immunity by bacteria. In the gram-negative mucosal pathogen Haemophilus ducreyi, serum resistance is mediated primarily by the trimeric autotransporter DsrA. DsrA also functions as an adhesin for the extracellular matrix proteins fibronectin and vitronectin and mediates attachment of H. ducreyi to keratinocytes. We sought to determine the domain(s) of the 236-residue DsrA protein required for serum resistance and extracellular matrix protein binding. A 140-amino-acid truncated protein containing only the C-terminal portion of the passenger domain and the entire translocator domain of DsrA exhibited binding to fibronectin and vitronectin and conferred serum resistance to an H. ducreyi serum-sensitive strain. A shorter DsrA construct consisting of only 128 amino acids was unable to bind to extracellular matrix proteins but was serum resistant. We concluded that neither fibronectin binding nor vitronectin binding is required for high-level serum resistance in H. ducreyi.
    Keywords: Bacterial Proteins -- Metabolism ; Carrier Proteins -- Metabolism ; Fibronectins -- Metabolism ; Haemophilus Ducreyi -- Metabolism ; Vitronectin -- Metabolism
    ISSN: 00199567
    E-ISSN: 1098-5522
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  • 2
    Language: English
    In: Personality and Individual Differences, 15 April 2017, Vol.109, pp.160-165
    Description: (vs. ) motivation has been found to lead to more successful goal attainment and reports of fewer obstacles. However, to date, only correlational research has been conducted. The present research experimentally examines the effects of motivation on the subjective perception of the frequency and disruptiveness of obstacles, and explores whether the results differ based on time (past vs. future obstacles). In four studies, participants were randomly assigned to or motivation for the goal of eating healthy and reported on the frequency and disruptiveness of obstacles encountered in the past week or anticipated in the coming week. Time moderated the effect of motivation such that motivation led to the perception of fewer and less disruptive obstacles, but only for future (not past) obstacles. The possible reasons for this discrepancy, and the implications for the relationship between motivation and goal pursuit are discussed.
    Keywords: Goal Pursuit ; Goal Motivation ; Obstacles ; Past and Future Time Frame ; Psychology
    ISSN: 0191-8869
    E-ISSN: 1873-3549
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  • 3
    Language: English
    In: Infection and immunity, December 2013, Vol.81(12), pp.4443-52
    Description: Haemophilus ducreyi is the etiologic agent of the sexually transmitted genital ulcer disease chancroid. In both natural and experimental chancroid, H. ducreyi colocalizes with fibrin at the base of the ulcer. Fibrin is obtained by cleavage of the serum glycoprotein fibrinogen (Fg) by thrombin to initiate formation of the blood clot. Fg binding proteins are critical virulence factors in medically important Gram-positive bacteria. H. ducreyi has previously been shown to bind Fg in an agglutination assay, and the H. ducreyi Fg binding protein FgbA was identified in ligand blotting with denatured proteins. To better characterize the interaction of H. ducreyi with Fg, we examined Fg binding to intact, viable H. ducreyi bacteria and identified a novel Fg binding protein. H. ducreyi bound unlabeled Fg in a dose-dependent manner, as measured by two different methods. In ligand blotting with total denatured cellular proteins, digoxigenin (DIG)-Fg bound only two H. ducreyi proteins, the trimeric autotransporter DsrA and the lectin DltA; however, only the isogenic dsrA mutant had significantly less cell-associated Fg than parental strains in Fg binding assays with intact bacteria. Furthermore, expression of DsrA, but not DltA or an empty vector, rendered the non-Fg-binding H. influenzae strain Rd capable of binding Fg. A 13-amino-acid sequence in the C-terminal section of the passenger domain of DsrA appears to be involved in Fg binding by H. ducreyi. Taken together, these data suggest that the trimeric autotransporter DsrA is a major determinant of Fg binding at the surface of H. ducreyi.
    Keywords: Bacterial Outer Membrane Proteins -- Metabolism ; Bacterial Proteins -- Metabolism ; Blood Bactericidal Activity -- Immunology ; Carrier Proteins -- Metabolism ; Chancroid -- Immunology
    E-ISSN: 1098-5522
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  • 4
    In: Infection and Immunity, 2009, Vol. 77(2), p.657
    ISSN: 0019-9567
    ISSN: 00199567
    Source: American Society of Microbiology
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  • 5
    Language: French
    In: Téoros, 2017, Vol.36(1)
    Description: Les sites candidats au titre de patrimoine mondial de l’UNESCO sont de plus en plus nombreux. Dans ce contexte de croissance et de compétition pour ce titre, cet article propose dans un premier temps une synthèse des valeurs associées au label et ensuite analyse la valence, positive, négative ou neutre, accordée aux valeurs par les parties prenantes associées à la promotion touristique d’une destination labellisée. Le cas de Québec permet de constater que les valeurs positives attribuées au label sont liées à la réputation du patrimoine mondial de l’UNESCO, à l’histoire et à la beauté de la ville.
    Keywords: Concilier Tourisme Et Développement Durable
    ISSN: 07128657
    E-ISSN: 1923-2705
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  • 6
    Language: French
    In: Téoros, 16 May 2017
    Description: Les sites candidats au titre de patrimoine mondial de l’UNESCO sont de plus en plus nombreux. Dans ce contexte de croissance et de compétition pour ce titre, cet article propose dans un premier temps une synthèse des valeurs associées au label et ensuite analyse la valence, positive, négative ou neutre, accordée aux valeurs par les parties prenantes associées à la promotion touristique d’une destination labellisée. Le cas de Québec permet de constater que les valeurs positives attribuées au label sont liées à la réputation du patrimoine mondial de l’UNESCO, à l’histoire et à la beauté de la ville.
    Keywords: UNESCO ; Patrimoine Mondial ; Label ; Valeur ; Tourisme ; Promotion ; Keywords: UNESCO ; World Heritage ; Label ; Value ; Tourism ; Promotion ; Geography
    ISSN: 0712-8657
    E-ISSN: 1923-2705
    Source: OpenEdition Journals
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  • 7
    Language: English
    In: Infection and immunity, August 2011, Vol.79(8), pp.3168-77
    Description: Haemophilus ducreyi, the etiologic agent of chancroid, has an obligate requirement for heme. Heme is acquired by H. ducreyi from its human host via TonB-dependent transporters expressed at its bacterial surface. Of 3 TonB-dependent transporters encoded in the genome of H. ducreyi, only the hemoglobin receptor, HgbA, is required to establish infection during the early stages of the experimental human model of chancroid. Active immunization with a native preparation of HgbA (nHgbA) confers complete protection in the experimental swine model of chancroid, using either Freund's or monophosphoryl lipid A as adjuvants. To determine if transfer of anti-nHgbA serum is sufficient to confer protection, a passive immunization experiment using pooled nHgbA antiserum was conducted in the experimental swine model of chancroid. Pigs receiving this pooled nHgbA antiserum were protected from a homologous, but not a heterologous, challenge. Passively transferred polyclonal antibodies elicited to nHgbA bound the surface of H. ducreyi and partially blocked hemoglobin binding by nHgbA, but were not bactericidal. Taken together, these data suggest that the humoral immune response to the HgbA vaccine is protective against an H. ducreyi infection, possibly by preventing acquisition of the essential nutrient heme.
    Keywords: Antibodies, Bacterial -- Administration & Dosage ; Bacterial Proteins -- Immunology ; Carrier Proteins -- Immunology ; Chancroid -- Prevention & Control ; Haemophilus Ducreyi -- Pathogenicity ; Immune Sera -- Administration & Dosage ; Immunization, Passive -- Methods
    ISSN: 00199567
    E-ISSN: 1098-5522
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  • 8
    Language: English
    In: Journal of Biological Chemistry, 03/03/1995, Vol.270(9), pp.4401-4404
    Description: Treatment of vascular smooth muscle cells (SMC) with angiotensin II (AII) leads to an increase in the tyrosine phosphorylation of multiple cellular substrates. Here, we have demonstrated that AII stimulates tyrosine phosphorylation of the focal adhesion-associated protein paxillin in rat aortic SMC. AII-induced phosphorylation of paxillin was detectable within 1 min and was sustained up to 60 min. Preincubation with the AT1-selective antagonist losartan abolished this response. The stimulatory effect of AII on paxillin tyrosine phosphorylation was observed only in aortic SMC and not in other target cells such as adrenal zona glomerulosa cells, chromaffin cells, or hepatocytes. The effect of AII was dependent on the activation of phospholipase C. Chelation of intracellular calcium completely inhibited the ability of AII to stimulate paxillin tyrosine phosphorylation, while selective inhibition of protein kinase C partially attenuated the response. In contrast, treatment of the cells with pertussis toxin had no effect on AII-induced paxillin tyrosine phosphorylation. These findings identify paxillin as a new substrate for AII-stimulated tyrosine phosphorylation and suggest a role for cytoskeleton-associated proteins in the growth response of aortic SMC.
    Keywords: Angiotensin II -- Pharmacology ; Cell Adhesion Molecules -- Metabolism ; Cytoskeletal Proteins -- Metabolism ; Muscle, Smooth, Vascular -- Metabolism ; Phosphoproteins -- Metabolism ; Tyrosine -- Metabolism;
    ISSN: 0021-9258
    E-ISSN: 1083-351X
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  • 9
    In: Infection and Immunity, 2010, Vol. 78(9), p.3763
    Description: Haemophilus ducreyi, the etiological agent of chancroid, has a strict requirement for heme, which it acquires from its only natural host, humans. Previously, we showed that a vaccine preparation containing the native hemoglobin receptor HgbA purified from H. ducreyi class I strain 35000HP (nHgbAI) and administered with Freund's adjuvant provided complete protection against a homologous challenge. In the current study, we investigated whether nHgbAI dispensed with monophosphoryl lipid A (MPL), an adjuvant approved for use in humans, offered protection against a challenge with H. ducreyi strain 35000HP expressing either class I or class II HgbA (35000HPhgbAI and 35000HPhgbAII, respectively). Pigs immunized with the nHgbAI/MPL vaccine were protected against a challenge from homologous H. ducreyi strain 35000HPhgbAI but not heterologous strain 35000HPhgbAII, as evidenced by the isolation of only strain 35000HPhgbAII from nHgbAI-immunized pigs. Furthermore, histological analysis of the lesions showed striking differences between mock-immunized and nHgbAI-immunized animals challenged with strains 35000HPhgbAI but not those challenged with strain 35000HPhgbAII. Mock-immunized pigs were not protected from a challenge by either strain. The enzyme-linked immunosorbent assay (ELISA) activity of the nHgbAI/MPL antiserum was lower than the activity of antiserum from animals immunized with the nHgbAI/Freund's vaccine; however, anti-nHgbAI from both studies bound whole cells of 35000HPhgbAI better than 35000HPhgbAII and partially blocked hemoglobin binding to nHgbAI. In conclusion, despite eliciting lower antibody ELISA activity than the nHgbAI/Freund's, the nHgbAI/MPL vaccine provided protection against a challenge with homologous but not heterologous H. ducreyi, suggesting that a bivalent HgbA vaccine may be needed.
    Keywords: Hemoglobin ; Hemoglobin Receptors ; Monophosphoryl Lipid A ; Antibodies ; Enzyme-Linked Immunosorbent Assay ; Heme ; Chancroid ; Vaccines ; Freund'S Adjuvant ; Immunization ; Haemophilus Ducreyi ; Microorganisms & Parasites ; Immunology;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 10
    Language: English
    In: Vaccine, 24 February 2016, Vol.34(9), pp.1193-1200
    Description: The Ducreyi serum resistance A (DsrA) protein of belongs to a large family of multifunctional outer membrane proteins termed trimeric autotransporter adhesins responsible for resistance to the bactericidal activity of human complement (serum resistance), agglutination and adhesion. The ability of DsrA to confer serum resistance and bind extracellular matrix proteins lies in its N-terminal passenger domain. We have previously reported that immunization with a recombinant form of the passenger domain of DsrA, rNT-DsrA, in complete/incomplete Freund's adjuvant, protects against a homologous challenge in swine. We present herein the results of an immunogenicity study in mice aimed at investigating the persistence, type of immune response, and the effect of immunization route and adjuvants on surrogates of protection. Our results indicate that a 20 μg dose of rNT-DsrA administered with alum elicited antisera with comparable bacterial surface reactivity to that obtained with complete/incomplete Freund's adjuvant. At that dose, high titers and bacterial surface reactivity persisted for 211 days after the first immunization. Administration of rNT-DsrA with CpG or imiquimod as adjuvants elicited a humoral response with similar quantity and quality of antibodies (Abs) as seen with Freund's adjuvant. Furthermore, intramuscular administration of rNT-DsrA elicited high-titer Abs with significantly higher reactivity to the bacterial surface than those obtained with subcutaneous immunization. All rNT-DsrA/adjuvant combinations tested, save CpG, elicited a Th2-type response. Taken together, these findings show that a 20 μg dose of rNT-DsrA administered with the adjuvants alum, CpG or imiquimod elicits high-quality Abs with reactivity to the bacterial surface that could protect against an infection.
    Keywords: Haemophilus Ducreyi ; Trimeric Autotransporter Adhesin ; Dsra ; Vaccine ; Medicine ; Biology ; Veterinary Medicine ; Pharmacy, Therapeutics, & Pharmacology
    ISSN: 0264-410X
    E-ISSN: 1873-2518
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