2006 Fiscal Year Final Research Report Summary
IDENTIFICATION OF GENES RELATING TO ENTAMOEBA EXCYSTATION AND ITS PROTEOMICS
| Project/Area Number |
16590348
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Parasitology (including Sanitary zoology)
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| Research Institution | Jikei University School of Medicine |
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Principal Investigator |
MAKIOKA Asao JIKEI UNIVERSITY, SCHOOL OF MEDICINE, ASSOCIATE PROFESSOR, 医学部, 助教授 (90119850)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Entamoeba / Excystation / GGT-I / Cytochalasin / Cysteine protease / Proteomics / SELDI-TOF / 2-D PAGE |
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| Research Abstract |
Excystation of Entamoeba includes reorganization of actin cytoskeleton, which is under control of the Ras superfamily small GTPases, Rho and Rac. These proteins need prenylation by a protein geranylgeranyltransferase type-I (GGT-I) for their function. We cloned genes encoding GGT-I and characterized recombinant enzyme. We showed biochemical differences between amebic and mammalian GGT-I. We examined whether other cytochalasins exhibit similar effects to cytochalasin D on Entamoeba excystation. Excystation was markedly enhanced by cytochalasin D as previously demonstrated, whereas the enhancing effect of cytochalasins A, B and dihydrocytochalasin B was weak and cytochalasin E inhibited excystation and metacystic development. These results indicate that there is a difference in the effect of different cytochalasins on the excystation of Entamoeba, depending on differences in their chemical structure. We showed that cysteine protease inhibitors block excystation and metacystic development
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of Entamoeba. There was a difference in the protease composition between cysts and trophozoites, and the protease composition of metacystic amoebae changed from cyst-type to trophozoite-type during development. These results strongly suggest that cysteine proteases contribute to the excystation and metacystic development of Entamoeba, which leads to successful infection. We examined the effect of artificial gastrointestinal fluid on these processes of Entamoeba and showed that gastric fluid but not intestinal fluid at 37℃ contributes to enhancing excystation for Entamoeba infection. Protein profiling by surface enhanced laser desorption ionization-time of flight mass spectrometry (SELDI-TOF-MS) ProteinChip assay with weak cationic exchange chips showed unique spectral profiles of cysts, metacystic amoebae and trophozoites. The results provide specific protein signatures for process of excystation and metacystic development of Entamoeba. Two-dimensional gel electrophoresis (2-D PAGE) also showed different spots among these three stages of Entamoeba. Less
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Research Products
(10 results)
