2001 Fiscal Year Final Research Report Summary
Development of "induces of β-lactam-susceptibility in MRSA (ILSMR)" and elucidaton of the novel regulatory mechanism
| Project/Area Number |
11558085
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Functional biochemistry
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| Research Institution | The University of Tokushima |
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Principal Investigator |
HIGUTI Tomihiko The University of Tokushima, Faculty of Pharmaceutical Sciences, Professor, 薬学部, 教授 (50035557)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Youichi Alps Pharmaceutical Industries, Co., Ltd., Natural Products Section Research And Development Department, Chief, 開発部第2室, 係長(研究職)
SHIBATA Hirofumi The University of Tokushima, Faculty of Pharmaceutical Sciences, Research Associate, 薬学部, 助手 (00093865)
ARAKAKI Naokatu The University of Tokushima, Faculty of Pharmaceutical Sciences, Associate Professor, 薬学部, 助教授 (60151148)
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| Project Period (FY) |
1999 – 2001
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| Keywords | MRSA / drug resistance / flavone / differential hybridization / vraR ＆ vraS / two component signal transduction / systemic infection in mice / inducers of β-lactam-susceptibility in MRSA (ILSMR) |
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| Research Abstract |
In order to develop novel effective drugs against infectious diseases caused by MRSA, we attempted to elucidate the mechanism of action of "inducers of β-lactam-susceptibility in MRSA (ILSMR)" and the novel mechanism of drug resistance of MRSA. In the present investigation, expression of mecA and that of penicilllin-binding protein 2' (PBP2') of MRSA, incubated with or without flavone, were analyzed by Northern and Western blottings, respectively. There were no change in mecA mRNA and the protein levels, indicating that the action of the ILSMR flavone is independent of the regularoty mechanism of mecA transcription system. To explore genes which are typically expressed or repressed by the ILSMR effect, cDNA differential hybridization was performed using RNAs extracted from MRSA strain No. 5-10 incubated with or without flavone. We found 26 clones which exhibited some changes in the expression levels under the present experimental conditions. Determination of the sequences and the homology search revealed that vraS and vraR expression were enhanced in the presence of flavone and the two component signal trans-duction system associated with the both genes may play an important role in the induction mechanism of β-lactam-susceptibility in MRSA.
We also found that flavone and its derivatives were highly active against systemic infections by MRSA in mice. In particular, TA1101 having no ILSMR effect in vitro revealed that mice were cured by the treatment with binary dose of the substance and a β-lactam antibiotic. It is interesting that such a curing effect of TA1101 was shown when it was orally administered before the mice were infected with MRSA.
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