Nature 1983, 305:709–712.CrossRefPubMed 59. Novick RP: Genetic systems in staphylococci. Methods Enzymol 1991, 204:587–636.CrossRefPubMed 60. Grkovic S, Brown MH, Hardie KM, Firth N, Skurray RA: Stable low-copy-number Staphylococcus

aureus shuttle vectors. Microbiology 2003, 149:785–794.CrossRefPubMed 61. Horsburgh MJ, Clements MO, Crossley H, Ingham E, Foster SJ: PerR controls oxidative stress resistance and iron storage proteins and is required for virulence in Staphylococcus aureus. Infect Immun 2001, 69:3744–3754.CrossRefPubMed 62. Hartleib J, Kohler N, Dickinson RB, Chhatwal GS, Sixma JJ, Hartford OM, Foster TJ, Peters G, Kehrel BE, Herrmann M: Protein A is the von Willebrand factor binding protein on Staphylococcus aureus. Blood 2000, 96:2149–2156.PubMed Roscovitine mw 63. Horsburgh MJ, Aish JL, White IJ, Shaw L, Lithgow JK, Foster SJ: sigmaB modulates virulence determinant expression and stress resistance: characterization Syk inhibitor of a functional rsbU strain derived from Staphylococcus aureus 8325–4. J Bacteriol 2002, 184:5457–5467.CrossRefPubMed Authors’ contributions ELC, JGL and SJF contributed in the design of the study and in the writing

of the manuscript. ELC and JGL carried out the genetic constructs necessary for the work and the determinations of ysxC essentiality. ELC performed the purification of YsxC partners, its subcellular localization, and its association with the ribosome. All authors read and approved manuscript.”
“Background Rhamnolipids are surface-active compounds that have been extensively C59 manufacturer studied since their early identification in Pseudomonas aeruginosa cultures in the late 1940s [1]. However, it was only in the mid 1960s that the structure of a rhamnolipid molecule was first reported [2]. Due to their excellent tensioactive properties, low toxiCity and high biodegradability, these biosurfactants are promising HSP targets candidates for a variety of

industrial applications as well as bioremediation processes [3, 4]. Furthermore, rhamnolipids have recently received renewed attention because of their involvement in P. aeruginosa multicellular behavior, such as biofilm development and swarming motility [5–7]. Rhamnolipids are also considered virulence factors as they interfere with the normal functioning of the tracheal ciliary system and are found in sputa of cystic fibrosis (CF) patients infected by P. aeruginosa [8–10]. Moreover, rhamnolipids inhibit the phagocytic response of macrophages and are known as the heat-stable extracellular hemolysin produced by P. aeruginosa [11, 12]. These amphiphilic molecules are usually produced by P. aeruginosa as a complex mixture of congeners composed of one or two molecules of L-rhamnose coupled to a 3-hydroxyalkanoic acid dimer, the most abundant being L-rhamnosyl-3-hydroxydecanoyl-3-hydroxydecanoate (Rha-C10-C10) and L-rhamnosyl-L-rhamnosyl-3-hydroxydecanoyl-3-hydroxydecanoate (Rha-Rha-C10-C10) [13–15].