Novel intercellular communication system in Escherichia coli that confers antibiotic resistance between physically separated populations.
OBJECTIVE
To determine whether intercellular signalling can occur between physically separated populations of Escherichia coli.


RESULTS
Intercellular signalling between physically discrete populations of E. coli BL21 was analysed in bi-partite Petri dishes. Transfer of a growth-promoting signal resulted in induction of resistance to the antibiotic ampicillin. Optimal expression of the signal occurred when the signalling population was established as a bacterial lawn for 24 h. This represented an entry into the stationary phase of growth, as indicated by the expression profile of the RNA polymerase subunit sigma38 (sigmaS; sigma S). The growth-promoting effect was also observed when E. coli DH5alpha (luxS-) was used as the signalling population. Preventing passage of air between the two populations resulted in a complete cessation of the growth-promoting effect.


CONCLUSIONS
A growth-promoting signal occurs between physically separated cultures of E. coli. The exact nature of the signal remains to be determined but does not involve the production of autoinducer-2 from the luxS gene. Signal transmission is likely to involve airborne transfer of a signal species.


CONCLUSIONS
Intercellular signalling systems exist in bacteria that enable antibiotic resistance to be conferred between physically separated populations.
Heal
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RD
BioPhysics Research Group, QinetiQ ltd., Winfrith Technology Centre, Dorchester, UK. rdheal@QinetiQ.com
Parsons
A T
AT
D000388:Air; D000668:Ampicillin Resistance / Q000502:physiology*; D001426:Bacterial Proteins / Q000502:physiology; D001431:Bacteriological Techniques; D013437:Carbon-Sulfur Lyases; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*
D001426:Bacterial Proteins; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria