The Influence of pH on the Specific Adhesion of P Piliated Escherichia coli

Adhesion to host tissues is an initiating step in a majority of bacterial infections. In the case of Gram-negative bacteria this adhesion is often mediated by a specific interaction between an adhesin, positioned at the distal end of bacterial pili, and its receptor on the surface of the host tissue. Furthermore, the rod of the pilus, and particularly its biomechanical properties, is believed to be crucial for the ability of bacteria to withstand external forces caused by, for example, (in the case of urinary tract infections) urinary rinsing flows by redistributing the force to several pili. In this work, the adhesion properties of P-piliated E. coli and their dependence of pH have been investigated in a broad pH range by both the surface plasmon resonance technique and force measuring optical tweezers. We demonstrate that P piliated bacteria have an adhesion ability throughout the entire physiologically relevant pH range (pH 4.5 - 8). We also show that pH has a higher impact on the binding rate than on the binding stability or the biomechanical properties of pili; the binding rate was found to have a maximum around pH 5 while the binding stability was found to have a broader distribution over pH and be significant over the entire physiologically relevant pH range. Force measurements on a single organelle level show that the biomechanical properties of P pili are not significantly affected by pH

P-fimbriae in the presence of anti-PapA antibodies : new insight of antibodies action against pathogens

Uropathogenic strains of Escherichia coli establish urinary tract infections by attaching to host epithelial cells using adhesive organelles called fimbriae. Fimbriae are helix-like structures with a remarkable adaptability, offering safeguarding for bacteria exposed to changing fluid forces in the urinary tract. We challenged this property of P-fimbriae by cross-linking their subunits with shaft-specific antibodies and measuring the corresponding force response at a single organelle level. Our data show compromised extension and rewinding of P-fimbriae in the presence of antibodies and reduced fimbrial elasticity, which are important properties of fimbriae contributing to the ability of bacteria to cause urinary tract infections. The reduced elasticity found by cross-linking fimbrial subunits could thus be another assignment for antibodies; in addition to marking bacteria as foreign, antibodies physically compromise fimbrial function. We suggest that our assay and results will be a starting point for further investigations aimed at inhibiting sustained bacterial adhesion by antibodies

Gender (in)equality within the household and business start-up among mothers

Using data on all businesses started by mothers of young children in Sweden between 2000 and 2014, we explore which factors are associated with entrepreneurship among mothers. We find that being unemployed or being an immigrant is positively associated with business start-up by mothers; however, our findings show that what matters more is the paternity leave taken by the mothers’ partners. These findings suggest that in institutional contexts such as Sweden, gender inequality is not a persistent feature of most households and that women can make career choices by negotiating with their partners who will make use of the parental benefits offered by the government

Backlash Men’s Movements Part 1: (Real) Fathers 4 Justice, bourgeois rational and new man/new father masculinities

Chapters 5 and 6 critically examine backlash men's movements, especially fathers’ rights groups and the politics of fatherhood. Both chapters are based on in-depth, qualitative analysis of interviews with members of (Real) Fathers 4 Justice. Chapter 5 explores two of three masculinities identified: “bourgeois-rational”, and “new man/new father” masculinity. These map on to specific constructions of fatherhood: “the good enough father”, and the “nurturing father” respectively, which are also explored. “Progressive” notions of crisis were associated with new man/new father masculinity, which advances a vision of kinder masculinity (without fundamentally unsettling gender binaries). Finally, the presence of feminist and postfeminist understandings of gender/fatherhood in fathers’ rights perspective is considered. The analysis demonstrates that men’s movements frequently shift discursive strategies and express ambivalence about feminism