Surface proteins that promote adherence of Staphylococcus aureus to human desquamated nasal epithelial cells

<p>Abstract</p> <p>Background</p> <p>The natural habitat of <it>Staphylococcus aureus </it>is the moist squamous epithelium in the anterior nares. About 20% of the human population carry <it>S. aureus </it>permanently in their noses and another 60% of individuals are intermittent carriers. The ability of <it>S. aureus </it>to colonize the nasal epithelium is in part due to expression of surface proteins clumping factor B (ClfB) and the iron-regulated surface determinant A (IsdA), which promote adhesion to desquamated epithelial cells present in the anterior part of the nasal vestibule. <it>S. aureus </it>strain Newman defective in IsdA and ClfB exhibited reduced but not completely defective adherence to squamous cells in indicating that other cell surface components might also contribute.</p> <p>Results</p> <p>Surface proteins IsdA, ClfB, and the serine-aspartic acid repeat proteins SdrC, SdrD and SdrE were investigated to determine their contribution to the adherence of <it>S. aureus </it>to desquamated nasal epithelial cells. This was achieved by expression of ClfB, IsdA, SdrC, SdrD and SdrE on the surface of the surrogate Gram-positive host <it>Lactococcus lactis </it>and by isolating mutants of <it>S. aureus </it>Newman defective in one or more factor. The level of adherence of strains to squamous cells isolated from the nares of volunteers was measured. Results consistently showed that ClfB, IsdA, SdrC and SdrD each contributed to the ability of <it>S. aureus </it>to adhere to squamous cells. A mutant lacking all four proteins was completely defective in adherence.</p> <p>Conclusion</p> <p>The ability of <it>S. aureus </it>Newman to adhere to desquamated nasal epithelial cells is multifactorial and involves SdrD and SdrC as well as ClfB and IsdA.</p

The N=1 supersymmetric bootstrap and Lie algebas

The bootstrap programme for finding exact S-matrices of integrable quantum field theories with N=1 supersymmetry is investigated. New solutions are found which have the same fusing data as bosonic theories related to the classical affine Lie algebras. When the states correspond to a spinor spot of the Dynkin diagram they are kinks which carry a non-zero topological charge. Using these results, the S-matrices of the supersymmetric O($2n$) sigma model and sine-Gordon model can be shown to close under the bootstrap.Comment: 21 pages, 3 figures (uses psfig.tex), plain tex with macro include

The immune evasion protein Sbi of Staphylococcus aureus occurs both extracellularly and anchored to the cell envelope by binding lipoteichoic acid

The Sbi protein of Staphylococcus aureus comprises two IgG-binding domains similar to those of protein A and a region that triggers the activation of complement C3. Sbi is expressed on the cell surface but its C-terminal domain lacks motifs associated with wall or membrane anchoring of proteins in Gram-positive bacteria. Cell-associated Sbi fractionates with the cytoplasmic membrane and is not solubilized during protoplast formation. S. aureus expressing Sbi truncates of the C-terminal Y domain allowed identification of residues that are required for association of Sbi with the membrane. Recombinant Sbi bound to purified cytoplasmic membrane material in vitro and to purified lipoteichoic acid. This explains how Sbi partitions with the membrane in fractionation experiments yet is partially exposed on the cell surface. An LTA-defective mutant of S. aureus had reduced levels of Sbi in the cytoplasmic membrane

Film as architectural theory

Publications on architectural theory have predominantly taken on the form of text-based books, monographs, and articles. With the rise of transdisciplinary and practice-based research in architecture, new opportunities are opening up for other forms of architectural theory, such as film-based mediums, which promise to expand and alter the convention of the written practice of theory. Two possible types of filmic theory are presented here. One follows the method of ethnographic documentary filmmaking inspired by Sarah Pinkfilm-based mediums, which promise to expand and alter thellows the line of art house filmmaking inspired by Kathryn Rameyyn Rameyg inspired by Sarah Pinkfilm-based mediums, which promise to expand ae to expand ad mediums, which promise to expand a convention of the written practice of theory. or constructing knowledge, new discourses on filmic theory can be opened up. It is argued here that film as architectural theory is part of this new discourse, broadening the audience’u engagement with architecture through not only “readership” but also “viewership.

Mutation discovery in mice by whole exome sequencing

We report the development and optimization of reagents for in-solution, hybridization-based capture of the mouse exome. By validating this approach in a multiple inbred strains and in novel mutant strains, we show that whole exome sequencing is a robust approach for discovery of putative mutations, irrespective of strain background. We found strong candidate mutations for the majority of mutant exomes sequenced, including new models of orofacial clefting, urogenital dysmorphology, kyphosis and autoimmune hepatitis