1996 Fiscal Year Final Research Report Summary
DEVELOPMENT OF NEW ANTIMICROBIAL PEPTIDE AGAINST METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS
| Project/Area Number |
07557115
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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 | 試験 |
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| Research Field |
Morphological basic dentistry
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
SUGINAKA Hidekazu HIROSHIMA UNIV.SCH.OF DENTISTRY,PROFESSOR, 歯学部, 教授 (70028736)
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| Co-Investigator(Kenkyū-buntansha) |
KOMATSUZAWA Hitoshi HIROSHIMA UNIV.SCH.OF DENTISTRY,RESEARCH ASSOCIATE, 歯学部, 助手 (90253088)
SUGAI Motoyuki HIROSHIMA UNIV.SCH.OF DENTISTRY,ASSOCIATE PROFESSOR, 歯学部, 助教授 (10201568)
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| Project Period (FY) |
1995 – 1996
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| Keywords | STAPHYLOCOCCUS AUREUS / AUTOLYSIN / PEPTIDOGLYCAN HYDROLASES / ATL / ANTIMICROBIAL PEPTIDE / MRSA |
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| Research Abstract |
The aim of this project was to develop a new antimicrobial peptide against methicillin resistant Staphylococcus aureus. We cloned the gene encoding major autolysin of S.aureus and found that atl gene products are responsible for cell separation of clusters. We also found that zymographic pattern of S.aureus lytic enzyme alters during growth and suggested that atl gene products undergo processing after it is secreted. Immunoelectronmicroscopical observation demonstrated that atl gene products are specifically localized on cell surface of S.aureus. Together with the data of unique autolytic figures of penicillin-treated S.aureus, we concluded that atl gene products are necessary for the autolysis of S.aureus treated with penicillin. Based on these observation, we synthsized several oligopeptides corresponding to the region of putative retention signal and investigated their effect on retention of atl gene products and penicillin induced autolysis. Under low ionic strength miliu, peptide A10, A11, A14 and A16 were found to decrease turbidity of S.aureus and cfu. By measuring decrease in turbidity, A10 and A14 were found to be inhibitory to autolysis and A11 and A16 were found to induce autolysis. These peptides contain positively chraged lysines, and addition of 50 mM NaCl was found to block the activity of these oligopeptide. TEM study clearly demonstrated that thin section of S.aureus which was induced autolysis by A11 or A16 shows the defect of cell wall corresponding to the site atl gene products localize. On theother hand, thin section of cells treated with A10 did not show any incidence of cell lysis, but revealed disturbance of cell membrane. These results strongly susggested that these synthtic peptides are able to show antimicrobial effect by interfering retention of atl gene products.
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