title: SdiA, an N-acylhomoserine lactone receptor, becomes active during the transit of Salmonella enterica through the gastrointestinal tract of turtles.
abstract: BACKGROUND
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Microbiology, The Ohio State University, Columbus, Ohio, United States of America.
authors.forename: Jenee N
authors.initials: JN
authors.lastname: Smith
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Dyszel
authors.forename: Jitesh A
authors.initials: JA
authors.lastname: Soares
authors.forename: Craig D
authors.initials: CD
authors.lastname: Ellermeier
authors.forename: Craig
authors.initials: C
authors.lastname: Altier
authors.forename: Sara D
authors.initials: SD
authors.lastname: Lawhon
authors.forename: L Garry
authors.initials: LG
authors.lastname: Adams
authors.forename: Vjollca
authors.initials: V
authors.lastname: Konjufca
authors.forename: Roy
authors.initials: R
authors.lastname: Curtiss
authors.forename: James M
authors.initials: JM
authors.lastname: Slauch
authors.forename: Brian M M
authors.initials: BM
authors.lastname: Ahmer
mesh_terms: D000333:Aeromonas / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism / Q000502:physiology*; D002417:Cattle; D002645:Chickens; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006168:Guinea Pigs; D007783:Lactones / Q000737:chemistry; D051379:Mice; D008808:Mice, Inbred CBA; D008954:Models, Biological; D011817:Rabbits; D019779:Salmonella enterica / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism / Q000502:physiology*; D014426:Turtles / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D007783:Lactones; C097686:SdiA protein, bacteria; D015534:Trans-Activators