Contribution of Coagulases towards Staphylococcus aureus Disease and Protective Immunity

The bacterial pathogen Staphylococcus aureus seeds abscesses in host tissues to replicate at the center of these lesions, protected from host immune cells via a pseudocapsule. Using histochemical staining, we identified prothrombin and fibrin within abscesses and pseudocapsules. S. aureus secretes two clotting factors, coagulase (Coa) and von Willebrand factor binding protein (vWbp). We report here that Coa and vWbp together are required for the formation of abscesses. Coa and vWbp promote the non-proteolytic activation of prothrombin and cleavage of fibrinogen, reactions that are inhibited with specific antibody against each of these molecules. Coa and vWbp specific antibodies confer protection against abscess formation and S. aureus lethal bacteremia, suggesting that coagulases function as protective antigens for a staphylococcal vaccine

Genetic Diversity of Staphylocoagulase Genes (coa): Insight into the Evolution of Variable Chromosomal Virulence Factors in Staphylococcus aureus

. Although SCs have been classified into 10 serotypes based on the differences in the antigenicity, genetic bases for their diversities and relatedness to chromosome types are poorly understood. type except for the cases of CC1 and CC8, which contained two and three different SC types, respectively. loci, resulting in the carriage of the combinations of allotypically different important virulence determinants in staphylococcal chromosome

Information Exchange and Distributional Implications of Price Discrimination with Internet Marketing in Agriculture

A price discrimination model is proposed to explain why firms provide extraneous information on Internet sites selling agricultural inputs. Whether an informative site is offered depends on price discrimination potential, which depends on how much farmers reveal heterogeneity by Internet behavior. Price discrimination is greater if information benefits are negatively correlated with farm size (or other characteristics), explaining why extraneous (not product-related) information is offered on Internet sales sites. Price discrimination adversely affects some farmers but may be beneficial on average because it generates free information. Outcomes depend on whether Internet users are aware of price differentials on the basis of clickstream information. Copyright 2006, Oxford University Press.

Purification of the extracellular opacity factor of a strain of group A Streptococcus M type 2

The extracellular Opacity Factor elaborated by a strain of group A streptococcus M type 2 was purified by ammonium sulphate precipitation, DEAE-cellulose and hydroxylapatite column chromatography and Sephadex G-200 gel filtration. Gel filtration experiments indicated that the Opacity Factor is consituted of high molecular weight proteins or protein aggregates which appear to dissociate into subunits of 66000 minimum molecular weight as determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The purified preparations had no group A carbohydrate of T protein antigens. Passive haemagglutination and indirect immunofluorescence tests indicated that Opacity Factor is distinct from the M type 2 protein antigen

Imbalanced sex ratios and housing prices in the U.S.

This paper investigates whether imbalanced local sex ratios are associated with housing prices in the U.S. at the county level during the period 2000–2017, based on the hypothesis that the importance for men of advertising financial resources by spending more on housing increases in the marriage market where there is a scarcity of women. The results indicate that an increase of 0.1 in sex ratio is associated with approximately a 2% increase in housing prices, suggesting that men may allocate more resources toward mating effort by increasing their spending on housing when there is an abundance of men. There is little evidence that the positive association was greater during the housing bubble