2007 Fiscal Year Final Research Report Summary
The study on control technique of oral biofilms using a quorum sensing circuit
| Project/Area Number |
17209061
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Conservative dentistry
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| Research Institution | Osaka University |
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Principal Investigator |
SHIGEYUKI Ebisu Osaka University, Graduate School of Dentistry, Professor (50116000)
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| Co-Investigator(Kenkyū-buntansha) |
NOIRI Yuichiro Osaka University, Graduate School of Dentistry, Assistant Professor (50218286)
SUGA Hiroaki The University of Tokyo, Research Center for Advanced Science and Technology, Professor (00361668)
AZAKAMI Hiroyuki Yamaguchi University, Faculty of Agriculture, Associate Professor (40263850)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Quorum sensing / Autoinducer / Oral biofilm / Porphyromonas gingivalie / Antagonist / modified Robbins device / Eikenella corrodens / LuxS gene |
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| Research Abstract |
We have investigated to develop the control methods and the inhibitor of the oral biofilm by use of the autoinducer (AI) associated with quorum sensing.
The effects of 20 kinds of AI analogs which we synthesized for this study were evaluated microbiologically and three-demensionally on the Porphymmonas gingivalis biofilm formation model in vitro. In 3 of the 20 AI analogs examined: C_16H_32N_2O, C_19H_29NO_3 and CuH_14N_2O_3 acted were antagonists for P. gingivalis biofilm formation. However other 9 AI analogs were significantly increased the quantity of biofilm forming cells. In the antagonist group, the thickness of the bioflims was in and the area of biofilm formation was shallow. In the antagonist group, the ability of attachment to the extracellular matrix and hemagglutination activity did not have of affected, but Kgp and Rgp activities were decreased at the high concentration (100 μM), and the pathogenicity was also influenced. These results are very important newly knowledge to
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carry out the experiment in vivo and the clinical clinical trial toward the development of the anti-biofilm drugs.
On the other hand, we detected that the periodontal pathogen Eikenella corrodens was observed to secrete type 2 signaling molecules. An ortholog of luxS which required for AI-2 synthesis, was isolated from the E corrodens 1073 genome. The bioassay showed luxS functionality in E. corrodens and the ability of luxS to complement the luxS negative phenotype of Escherichia coli DH5α. An E corrodens luxS mutant was constructed and tested for its capacity to form an in vitro biofilm on both static and flow cell models. On the static model, the biofilm farming ability of the luxS mutant was approximately 1.3-fold greater than that of the wild type. On the flow cell model, however biofilm forming ability of the luxS mutant was significantly reduced and cell density was low three-dimensionally compared with those of the wild type. It became clearly that not only luxS but also several genes associated with the maturation of E corrodens biofilm, but the luxS mutant played an important role in the initial biofilm formation. Less
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