SdiA, an N-acylhomoserine lactone receptor, becomes active during the transit of Salmonella enterica through the gastrointestinal tract of turtles

• Published in: PloS one 2008-07, Vol.3 (7), p.e2826-e2826
• Main Authors: Smith, Jenee N, Dyszel, Jessica L, Soares, Jitesh A, Ellermeier, Craig D, Altier, Craig, Lawhon, Sara D, Adams, L Garry, Konjufca, Vjollca, Curtiss, 3rd, Roy, Slauch, James M, Ahmer, Brian M M
• Format: Article
• Language: English
• Subjects: Aeromonas - metabolism; Aeromonas hydrophila; Animal species; Animals; Antibiotics; Bacteria; Bacterial Proteins - metabolism; Bacterial Proteins - physiology; Cattle; Chickens; DNA binding proteins; E coli; Ecology/Environmental Microbiology; Escherichia; Escherichia coli; Female; Gastrointestinal system; Gastrointestinal tract; Gastrointestinal Tract - microbiology; Gene expression; Genetic engineering; Gram-negative bacteria; Guinea Pigs; Lactones; Lactones - chemistry; Medical laboratories; Mice; Mice, Inbred CBA; Microbiology/Cellular Microbiology and Pathogenesis; Microbiology/Medical Microbiology; Microbiota (Symbiotic organisms); Models, Biological; Mutagenesis; Pigs; Population; Population density; Poultry; Pseudemys; Pseudomonas aeruginosa; Rabbits; Reptiles & amphibians; Salmonella; Salmonella enterica; Salmonella enterica - metabolism; Salmonella Typhimurium; Species; Surveillance; Trans-Activators - metabolism; Trans-Activators - physiology; Transcription factors; Transit; Turtles; Turtles - microbiology; Veterinary colleges; Veterinary medicine
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0002826

LuxR-type transcription factors are typically used by bacteria to determine the population density of their own species by detecting N-acylhomoserine lactones (AHLs). However, while Escherichia and Salmonella encode a LuxR-type AHL receptor, SdiA, they cannot synthesize AHLs. In vitro, it is known that SdiA can detect AHLs produced by other bacterial species. In this report, we tested the hypothesis that SdiA detects the AHL-production of other bacterial species within the animal host. SdiA did not detect AHLs during the transit of Salmonella through the gastrointestinal tract of a guinea pig, a rabbit, a cow, 5 mice, 6 pigs, or 12 chickens. However, SdiA was activated during the transit of Salmonella through turtles. All turtles examined were colonized by the AHL-producing species Aeromonas hydrophila. We conclude that the normal gastrointestinal microbiota of most animal species do not produce AHLs of the correct type, in an appropriate location, or in sufficient quantities to activate SdiA. However, the results obtained with turtles represent the first demonstration of SdiA activity in animals.