2% serum at 37°C with shaking. Cultures were diluted 1:100 in fresh broth and allowed to shake at 37°C until they reached an absorbance of 1 at 600 nm (A600nm) corresponding to exponentially growing bacteria. For whole culture lysates

(samples labeled T, for total culture extracts as shown in Figures 2A and 3), cultures (6 ml) were incubated in the presence of selleck chemicals llc lysostaphin (100 μg/ml) for 30 min at 37°C. To separate proteins in the culture medium (M) from those in the bacterial cell (C), cultures (6 ml) were centrifuged (10,000 ×  g for 10 min) and the supernatant was transferred to a new tube prior to lysostaphin treatment of intact cells. For subcellular localization of EssB (Figures 1A and 5 top panel), cultures GANT61 were centrifuged to separate medium and cells. Staphylococci were washed, and peptidoglycan digested with lysostaphin.

Staphylococcal extracts were subjected to ultracentrifugation at 100,000 ×  www.selleckchem.com/products/bix-01294.html g for 40 min at 4°C. The supernatant, containing soluble proteins (S), was transferred to a new tube. The sediment containing insoluble membrane proteins (I), was suspended in 6 ml PBS buffer. Proteins in all samples were precipitated with 10% trichloroacetic acid on ice for 30 min. Precipitates were sedimented by centrifugation at 15,000 ×  g , washed, dried and solubilized in 100 μl of 0.5 M Tris–HCl (pH 8.0)/4% SDS and heated at 90°C for 10 min. Proteins were separated on SDS/PAGE and transferred to poly(vinylidene difluoride) membrane for immunoblot analysis with appropriate polyclonal antibodies. Immunoreactive signals were CYTH4 revealed by using a secondary antibody coupled to IRDye© 680. Quantification of western blots

was conducted using a Li-Cor Biosciences Odyssey imager. Briefly, cells were grown to the same optical density. All strains reached similar density in the same time period suggesting that either deletion or cis -expression of genes did not affect growth of bacteria. Signal intensity of immune reactive signals for EsxA, EssB, EsaB and EsaD was compared to that obtained for WT, WT/vector, essB /p essB or WT/p essB sample extracts for Figures 2, 3, 5 A, B, C and D, respectively. Immune reactive signals (as shown in Figure 3) were averaged in three independent experiments and the data was analyzed in pairwise comparisons between WT/vector and variant strains with the unpaired two-tailed Student’s t -test and found to be statistically significant. Protein and polyclonal antibody purification Briefly, recombinant EssB, EssBNM, EssBMC, EssBΔM, tagged with N-terminal hexa-histidine were purified using Ni-NTA Agarose (Qiagen) following manufacturer’s recommendations.