Nesse et al. Acta Veterinaria Scandinavica 2011, 53:44 http://www.actavetscand.com/content/53/1/44 gene in peritoneal and splenic macrophages isolated in vitro. J Immunol 1983, 131:3006-3013. 7. Tedin K, Blasi U: The RNA chain elongation rate of the lambda late mRNA is unaffected by high levels of ppGpp in the absence of amino acid starvation. J Biol Chem 1996, 271:17675-17686. 8. Ahmer BM, van RJ, Timmers CD, Valentine PJ, Heffron F: Salmonella typhimurium encodes an SdiA homolog, a putative quorum sensor of the LuxR family, that regulates genes on the virulence plasmid. J Bacteriol 1998, 180:1185-1193. 9. Crago AM, Koronakis V: Binding of extracellular matrix laminin to Escherichia coli expressing the Salmonella outer membrane proteins Rck and PagC. FEMS Microbiol Lett 1999, 176:495-501. 10. Rosselin M, Virlogeux-Payant I, Roy C, Bottreau E, Sizaret PY, Mijouin L, et al: Rck of Salmonella enterica, subspecies enterica serovar Enteritidis, mediates Zipper-like internalization. Cell Res 2010, 20:647-664. 11. Bouwman CW, Kohli M, Killoran A, Touchie GA, Kadner RJ, Martin NL: Characterization of SrgA, a Salmonella enterica serovar Typhimurium virulence plasmid-encoded paralogue of the disulfide oxidoreductase DsbA, essential for biogenesis of plasmid-encoded fimbriae. J Bacteriol 2003, 185:991-1000. 12. Nicholson B, Low D: DNA methylation-dependent regulation of pef expression in Salmonella typhimurium. Mol Microbiol 2000, 35:728-742. 13. Samudrala R, Heffron F, McDermott JE: Accurate prediction of secreted substrates and identification of a conserved putative secretion signal for type III secretion systems. PLoS Pathog 2009, 5:e1000375. 14. Erickson DL, Nsereko VL, Morgavi DP, Selinger LB, Rode LM, Beauchemin KA: Evidence of quorum sensing in the rumen ecosystem: detection of N-acyl homoserine lactone autoinducers in ruminal contents. Can J Microbiol 2002, 48:374-378. 15. Smith JN, Dyszel JL, Soares JA, Ellemeier CD, Altier C, Lawhon SD, et al: SdiA, an N-Acylhomoserine Lactone Receptor, becomes active during the transit of Salmonella enterica through the gastrointestinal tract of turtles. PLoS ONE 2008, 3:e2826. 16. Dyszel JL, Smith JN, Lucas DE, Soares JA, Swearingen MC, Vross MA, et al: Salmonella enterica serovar Typhimurium can detect acyl homoserine lactone production by Yersinia enterocolitica in mice. J Bacteriol 2010, 192:29-37. doi:10.1186/1751-0147-53-44 Cite this article as: Nesse et al.: Salmonella Typhimurium invasion of HEp-2 epithelial cells in vitro is increased by N-acylhomoserine lactone quorum sensing signals. Acta Veterinaria Scandinavica 2011 53:44. Page 5 of 5 Submit your next manuscript to BioMed Central and take full advantage of: • Convenient online submission • Thorough peer review • No space constraints or color ﬁgure charges • Immediate publication on acceptance • Inclusion in PubMed, CAS, Scopus and Google Scholar • Research which is freely available for redistribution Submit your manuscript at www.biomedcentral.com/submit