Identification of a quorum-sensing signal molecule in the facultative intracellular pathogen Brucella melitensis.
Brucella melitensis is a gram-negative alpha2-proteobacterium responsible for abortion in goats and for Malta fever in humans. This facultative intracellular pathogen invades and survives within both professional and nonprofessional phagocytes. A dichloromethane extract of spent culture supernatant from B. melitensis induces bioluminescence in an Escherichia coli acyl-homoserine lactone (acyl-HSL) biosensor strain based upon the activity of the LasR protein of Pseudomonas aeruginosa. HPLC fractionation of the extract, followed by mass spectrometry, identified the major active molecule as N-dodecanoylhomoserine lactone (C12-HSL). This is the first report of the production of an acyl-HSL by an intracellular pathogen. The addition of synthetic C12-HSL to an early log phase culture of either B. melitensis or Brucella suis 1330 reduces the transcription of the virB operon, which contains virulence genes known to be required for intracellular survival. This mimics events seen during the stationary phase of growth and suggests that quorum sensing may play a role in the control of virulence in Brucella.
Taminiau
Bernard
B
Unité de Recherche en Biologie Moléculaire (URBM), Laboratoire d'Immunologie et Microbiologie, Facultés Universitaires Notre-Dame de la Paix, 5000 Namur, Belgium. Bernard.Taminiau@fundp.ac.be
Daykin
Mavis
M
Swift
Simon
S
Boschiroli
Maria-Laura
ML
Tibor
Anne
A
Lestrate
Pascal
P
De Bolle
Xavier
X
O'Callaghan
David
D
Williams
Paul
P
Letesson
Jean-Jacques
JJ
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D017347:Brucella melitensis / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media; D007424:Intracellular Fluid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D037521:Virulence Factors
D001426:Bacterial Proteins; D003470:Culture Media; D014157:Transcription Factors; D037521:Virulence Factors; C088386:homoserine lactone; D015107:4-Butyrolactone