In conclusion, the results are consistent with a model where, in Mycobacteria, one chaperonin (Cpn60.2) acts as the main housekeeping chaperonin in the cell, folding a range of client proteins both under normal growth conditions click here and after stresses such as heat shock, while the other (Cpn60.1) has evolved to have more specialized functions that are not

essential for viability, although they are also heat shock sensitive. The role of the Cpn60.3 protein that has been acquired recently by horizontal gene transfer is not known, but considering the expression levels, it is not likely to be significant. We are grateful for the financial support from the Darwin Trust of Edinburgh Lenvatinib nmr (studentship to T.R.). We would like to thank Prof. D. Chatterji (IISc, Bangalore) for the generous gift of plasmid pSD5B. “
“Pseudomonas aeruginosa is a free-living bacterium and an important opportunistic pathogen. The genes coding for virulence-associated traits are regulated at the level of transcription by the quorum-sensing response. In this response, the regulator LasR coupled with the autoinducer 3-oxo-dodecanoyl homoserine lactone (3O-C12-HSL) activates transcription of genes for several virulence factors. LasR/3O-C12-HSL also activates transcription of rhlR, the gene

coding for the transcriptional regulator RhlR, and of rhlI that encodes the

synthase that produces the autoinducer butanoyl-homoserine lactone (C4-HSL) that interacts with RhlR. Genes activated by RhlR/C4-HSL include those involved in rhamnolipids production (like the rhlAB operon) and lecA, coding for PA-I lectin. The molecular basis of LasR/3O-C12-HSL- and RhlR/C4-HSLDNA-binding LY294002 specificity (at the so-called las-boxes) has not been clearly determined, and the aim of this work was to contribute to its understanding. Therefore, we analyzed the interaction of LasR and RhlR to variants of the rhlA-las-box that were constructed based on the comparison of this las-box to the las-box of lecA. We conclude that LasR and RhlR DNA-binding specificity is a complex multifactorial phenomenon in which both positive and negative effects are involved and that binding of these proteins does not necessarily result in gene activation. “
“Cell surface pili have recently been found in many different bifidobacterial species, including the infant gut commensal Bifidobacterium bifidum PRL2010. Pili produced by PRL2010 have been shown to be important molecular mediators for bacterial interaction with its human host. However, nothing is known about the modulation of their expression in response to cues that reflect the gastro intestinal environment, such as thermal, acidic, and osmotic challenges, or the presence of other gut microorganisms.