In follow-up work to this paper, it was found that the identification of an acetylglycerol in the polysaccharide repeating unit is incorrect. The proper placement of the O-acetate group is on -gal C6. The incorrect assignment occurred due to incorrect interpretation of NMR data, which was discovered while working on other polysaccharides that are structurally related to serotype 11A (Calix, J. J., Nahm, M. H., and Zartler, E. R. (2011) J. Bacteriol. 193,[5271][5272][5273][5274][5275][5276][5277][5278]. This correction does not impact the assignment of the other acetyl groups. Also, the correction does not change any genetic and serologic findings described in the paper. The first author, Edward R. Zartler, takes full responsibility for this matter and apologizes for any inconvenience caused. A detailed description of this correction is given in Calix, J. J., Nahm, M. H., and Zartler, E. R. (2011)
ADDITIONS AND CORRECTIONS
This paper is available online at www.jbc.orgWe suggest that subscribers photocopy these corrections and insert the photocopies in the original publication at the location of the original article. Authors are urged to introduce these corrections into any reprints they distribute. Secondary (abstract) services are urged to carry notice of these corrections as prominently as they carried the original abstracts.
Cellulose is a major component of the Salmonella biofilm extracellular matrix and it is considered an antivirulence factor because it interferes with Salmonella survival inside macrophages and virulence in mice. Its synthesis is stimulated by CsgD, the master regulator of biofilm extracellular matrix formation in enterobacteria, which in turn is under the control of MlrA, a MerR-like transcription factor. In this work we identified a SPI-2 encoded Salmonella-specific transcription factor homolog to MlrA, MlrB, that represses transcription of its downstream gene, STM1389, also known as orf319, and of csgD inside host cells. MlrB is induced in laboratory media mimicking intracellular conditions and inside macrophages, and it is required for intramacrophage survival. An increased expression of csgD is observed in the absence of MlrB inside host cells. Interestingly, inactivation of the CsgD-controlled cellulose synthase coding-gene, bcsA, restored intramacrophage survival to rates comparable to wild type bacteria in the absence of MlrB. These data indicate that MlrB represses CsgD expression inside host cells and in consequence activation of the cellulose synthase. Our findings provide a novel link between biofilm formation and Salmonella virulence.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.