Peptidoglycan editing in non-proliferating intracellular Salmonella as source of interference with immune signaling.

Salmonella enterica causes intracellular infections that can be limited to the intestine or spread to deeper tissues. In most cases, intracellular bacteria show moderate growth. How these bacteria face host defenses that recognize peptidoglycan, is poorly understood.

Publisher Correction: HilD and PhoP independently regulate the expression of grhD1, a novel gene required for Salmonella Typhimurium invasion of host cells.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

HilD and PhoP independently regulate the expression of grhD1, a novel gene required for Salmonella Typhimurium invasion of host cells.

When Salmonella is grown in the nutrient-rich lysogeny broth (LB), the AraC-like transcriptional regulator HilD positively controls the expression of genes required for Salmonella invasion of host cells, such as the Salmonella pathogenicity island 1 (SPI-1) genes. However, in minimal media, the two-component system PhoP/Q activates the expression of genes necessary for Salmonella replication inside host cells, such as the SPI-2 genes. Recently, we found that the SL1344_1872 hypothetical gene, located in a S.

A Specialized Peptidoglycan Synthase Promotes Cell Division inside Host Cells.

Bacterial cell division has been studied extensively under laboratory conditions. Despite being a key event in the bacterial cell cycle, cell division has not been explored in bacterial pathogens interacting with their hosts. We discovered in serovar Typhimurium a gene absent in nonpathogenic bacteria and encoding a peptidoglycan synthase with 63% identity to penicillin-binding protein 3 (PBP3).

A novel peptidoglycan D,L-endopeptidase induced by Salmonella inside eukaryotic cells contributes to virulence.

Bacteria remodel peptidoglycan structure in response to environmental changes. Many enzymes are involved in peptidoglycan metabolism; however, little is known about their responsiveness in a defined environment or the modes they assist bacteria to adapt to new niches. Here, we focused in peptidoglycan enzymes that intracellular bacterial pathogens use inside eukaryotic cells.

Increased bile resistance in Salmonella enterica mutants lacking Prc periplasmic protease.

Prc is a periplasmic protease involved in processing of penicillin-binding protein 3 (PBP3). Lack of Prc suppresses bile sensitivity in Dam-, Wec-, PhoP-, DamX-, and SeqA- mutants of Salmonella enterica, and increases bile resistance in the wild type. Changes in the activity of penicillin binding proteins PBP3, PBP4, PBP5/6 and PBP7 are detected in a Prc- background, suggesting that peptidoglycan remodeling might contribute to bile resistance.

A novel antisense RNA from the Salmonella virulence plasmid pSLT expressed by non-growing bacteria inside eukaryotic cells.

Bacterial small RNAs (sRNAs) are regulatory molecules playing relevant roles in response to environmental changes, stressful conditions and pathogenesis. The intracellular bacterial pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) is known to regulate expression of some sRNAs during colonization of fibroblasts.