Comparative proteomics of Staphylococcus aureus and the response of methicillin-resistant and methicillin-sensitive strains to Triton X-100 a aThe identifications for the spots shown in Fig. 1 F1 can be found as supplementary data in Microbiology Online (http://mic.sgmjournals.org).

Abstract

Proteomics is a powerful tool for analysing differences in gene expression between bacterial strains with alternate phenotypes. Staphylococcus aureus strains are grouped on the basis of their sensitivity to methicillin. Twodimensional gel electrophoresis was combined with MS to compare the protein profiles of S. aureus strains COL (methicillin-resistant) and 8325 (methicillinsensitive). Reference mapping via this approach identified 377 proteins that corresponded to 266 distinct ORFs. Amongst these identified proteins were 14 potential virulence factors. The production of 41 ' hypothetical ' proteins was confirmed, and eight of these appeared to be unique to S. aureus. Strain COL displayed 12 protein spots, which included alkaline-shock protein 23 (Asp23) and cold-shock proteins CspABC, which either were not present in strain 8325 or were present at a significantly lower intensity in this strain. Comparative maps were used to characterize the S. aureus response to treatment with Triton X-100 (TX-100), a detergent that has been shown to reduce methicillin resistance independently of an interaction with the mecA-encoded penicillinbinding protein 2a. In response to growth of the bacteria in the presence of TX-100, 44 protein spots showed altered levels of abundance, and 11 of these spots were found only in COL. The products of genes regulated by σ B (the alternative sigma factor), including Asp23 and three proteins of unknown function, and SarA (a regulator of virulence genes) were shown to be present at significantly altered levels. SarA production was induced in TX-100-treated cultures. A protein of the σ B operon, RsbV, was only detected in COL and its production was down-regulated in COL when the strain was treated with TX-100, whereas RsbW was present at reduced levels in both strains. Upon growth of both strains in the presence of TX-100, no effects on the production of the essential methicillin-resistance factor FemA were detected, whereas phosphoglucosamine mutase (GlmM) production was reduced in COL alone. This study suggests that proteins of the σ B and sarA regulons, as well as other factors, are involved in methicillin resistance in S. aureus.

Isobaric Tags for Relative and Absolute Quantitation Proteomics Analysis of Gene Regulation by SprC in Staphylococcus Aureus

“…For instance, in the operon expressing proteins SA1119, SA1120, SA1121, SA1122 and SA1123, only SA1119 (FtsK/SpoIII E family protein) was detected in proteomics study. This phenomenon has also been found in previous studies [47,48]. The potential explanations may be diverse modification in transcriptional and translational level, some intracellular chemical reaction and/or the presence of protease affecting the amount of protein.…”

Antagonistic activity of cellular components of Pseudomonas species against Aeromonas hydrophila

“…The Pseudomonas species as a fungicide to protect the food from toxic fungi such as penicillium and botrytis. The protein patterns of the different strains of Staphyloccus aureus and Lactobacillus sanfranciscensis are resistant to specific antibiotics (De Angelis et al, 2001;Cordwell et al, 2002;Hecker et al, 2003).…”

Up-regulation of competence- but not stress-responsive proteins accompanies an altered metabolic phenotype in Streptococcus mutans biofilms

“…The precipitated proteins from the 'wall', 'cytoplasmic' or 'membrane' fractions were resuspended in 900 ml of a 2 : 3 mixture of Cellular and Organelle Membrane Solubilizing Reagent and 2-DGE solubilizing solution (modified from Cordwell et al, 2002) and consisting of 5 M urea, 2 M thiourea, 2 % (w/v) CHAPS, 2 % (w/v) caprylyl sulfobetaine, 1?0 % (v/v) Triton X-100, 2 mM tributylphosphine, 0?2 % (v/v) carrier ampholytes (pH 3-10), 40 mM Tris and 0?002 % (w/v) bromophenol blue, sonicated to facilitate resuspension (Branson 450, 130 W, 2610 s, 4 uC with cooling on ice between each burst) and incubated at room temperature (20-22 uC) for 45 min. Freshly prepared iodoacetamide was then added to each sample to give a final concentration of 15 mM and the incubation continued for a further 45 min at room temperature.…”