Formate Acts as a Diffusible Signal To Induce Salmonella Invasion
- 15 June 2008
- journal article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 190 (12), 4233-4241
- https://doi.org/10.1128/jb.00205-08
Abstract
To infect an animal host, Salmonella enterica serovar Typhimurium must penetrate the intestinal epithelial barrier. This process of invasion requires a type III secretion system encoded within Salmonella pathogenicity island I (SPI1). We found that a mutant with deletions of the acetate kinase and phosphotransacetylase genes ( ackA-pta ) was deficient in invasion and SPI1 expression but that invasion gene expression was completely restored by supplying medium conditioned by growth of the wild-type strain, suggesting that a signal produced by the wild type, but not by the ackA-pta mutant, was required for invasion. This mutant also excreted 68-fold-less formate into the culture medium, and the addition of sodium formate to cultures restored both the expression of SPI1 and the invasion of cultured epithelial cells by the mutant. The effect of formate was pH dependent, requiring a pH below neutrality, and studies in mice showed that the distal ileum, the preferred site of Salmonella invasion in this species, had the appropriate formate concentration and pH to elicit invasion, while the cecum contained no detectable formate. Furthermore, we found that formate affected the major regulators of SPI1, hilA and hilD , but that the primary routes of formate metabolism played no role in its activity as a signal.This publication has 74 references indexed in Scilit:
- An obesity-associated gut microbiome with increased capacity for energy harvestNature, 2006
- A humanized gnotobiotic mouse model of host–archaeal–bacterial mutualismProceedings of the National Academy of Sciences of the United States of America, 2006
- Metagenomic Analysis of the Human Distal Gut MicrobiomeScience, 2006
- Identification of CsrC and Characterization of Its Role in Epithelial Cell Invasion in Salmonella enterica Serovar TyphimuriumInfection and Immunity, 2006
- Obesity alters gut microbial ecologyProceedings of the National Academy of Sciences of the United States of America, 2005
- Transcriptional regulation ofSalmonella entericaserovar Typhimurium genes by bileFEMS Immunology & Medical Microbiology, 2004
- RtsA and RtsB Coordinately Regulate Expression of the Invasion and Flagellar Genes inSalmonella entericaSerovar TyphimuriumJournal of Bacteriology, 2003
- Identification of the formate dehydrogenases and genetic determinants of formate-dependent nitrite reduction by Escherichia coli K12Journal of General Microbiology, 1993
- Comparison of fermentation reactions in different regions of the human colonJournal of Applied Bacteriology, 1992
- Comparison of fermentation reactions in different regions of the human colonJournal of Applied Microbiology, 1992