| Co-Investigator(Kenkyū-buntansha) |
USUKI Yoshinosuke Osaka City University, Graduate School of Science, Lecturer, 大学院理学研究科, 講師 (30244651)
HARUMOTO Terue Nara Women's University, Faculty of Science, Professor, 理学部, 教授 (80198936)
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| Budget Amount *help |
¥15,500,000 (Direct Cost: ¥15,500,000)
Fiscal Year 2006: ¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2005: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2004: ¥9,600,000 (Direct Cost: ¥9,600,000)
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| Research Abstract |
In the continuing study on predator-prey interaction between ciliates, we reported the isolation and structural determination of a defense toxin climacostol from a heterotrich ciliate Climacostomum virens. On the preliminary study of the predator-prey interaction between ciliates Dileptus margaritifer as a predator and Spirostomum teres an another heterotrich ciliate as a prey, we observed elusive behavior of S.teres from the predator and the presence of the cortical vesicle in S.teres just beneath the cell membrane, which suggested that S.teres had some toxic substance against the predator. We report the isolation and structural determination of a toxic substance spirortomin from S.teres.
The whole cells of S.teres were dipped in aqueous 70% EtOH. After removal of the cells by filtration and concentration of the solvent, the residue was partitioned between ethyl acetate and water. From the organic layer, an active fraction based on lethal toxicity against a ciliate Paramecium caudatum
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was obtained by chromatography on silica gel eluted with 1.5% Me0H/CH_2C_<12> (Rf value 0.44). The fraction contained a new compound spirostomin (1), whose molecular formula was estimated to be C_<16>H_<14>O_5 by HREIMS and ^1H and ^<13>C NMR. Based on ^1H, ^<13>C NMR and UV spectra, the structure of spirostomin was established as spiro[(2,5-dimethy1-5,6,7,8-tetrahydronaphtalene-1,4-dione)-8,6'- (pyrane-2',5'-dione)], a spiro compound having a carbon framework hitherto unknown. The relative stereochemistry of spirostomin was established by the total synthesis of spirostomine A and B. The absolute chemistry of spirostomine was also estimated by the CD spectra and the result based on the DFT calculation.
Blepharismins, toxic pigments of the ciliate Blepharisma japonicum, are polycyclic ring-condensed compounds. Assignment of ^<13>C NMR signals for blepharismin C, a major constituent of blepharismins, was achieved by analyses of the HMQC, HMBC, and INADEQUATE spectra of 13C-enriched samples obtained by feeding experiments using sodium [1-13C], [2-13C], and [1,2-^<13>C2]acetates. Less
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