Effects of N-acyl homoserine lactone analogues on Porphyromonas gingivalis biofilm formation.
OBJECTIVE
The gram-negative anaerobic rod Porphyromonas gingivalis in oral biofilms is a primary etiological agent of periodontal disease. Biofilm formation of various gram-negative bacteria is regulated by a quorum-sensing circuit that relies on N-acyl homoserine lactones (HSLs). Some synthetic N-acyl HSL analogues act as quorum-sensing inhibitors and suppress biofilm formation in Pseudomonas aeruginosa. Development of chemical control agents against oral biofilms is necessary, because until now, biofilms have been removed only by mechanical debridement. The present study investigated the effect of N-acyl HSL analogues on P. gingivalis biofilm formation, with the aim of developing new drugs that inhibit oral biofilm formation.


METHODS
A flow-cell model was used for P. gingivalis biofilm formation. Seventeen synthetic N-acyl HSL analogues were quantitatively assessed by spectrophotometry. The effects of three antagonistic compounds against P. gingivalis biofilm formation were further examined by confocal laser scanning microscopy, and investigated for primary attachment using spectrophotometry and phase contrast microscopy.


RESULTS
Ten out of 17 analogues affected P. gingivalis biofilm formation. Three out of 10 analogues significantly decreased biofilm-forming cells (p < 0.05), and these biofilm structures were less well formed three-dimensionally. There were no quantitative or qualitative differences in cell attachment between the control and the three analogue-treated groups.


CONCLUSIONS
Three synthetic N-acyl HSL analogues inhibited biofilm formation in P. gingivalis. We suggest that these analogues influence the development stage of P. gingivalis biofilm formation.
Asahi
Y
Y
Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.
Noiri
Y
Y
Igarashi
J
J
Asai
H
H
Suga
H
H
Ebisu
S
S
D054742:Acyl-Butyrolactones / Q000737:chemistry / Q000145:classification / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D001431:Bacteriological Techniques; D018441:Biofilms / Q000187:drug effects*; D004396:Coloring Agents; D006801:Humans; D021621:Imaging, Three-Dimensional; D018613:Microscopy, Confocal; D008858:Microscopy, Phase-Contrast; D016966:Porphyromonas gingivalis / Q000187:drug effects* / Q000502:physiology; D053038:Quorum Sensing / Q000187:drug effects; D013053:Spectrophotometry
D054742:Acyl-Butyrolactones; D004396:Coloring Agents