Yuji Ise

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Six linear acetylenes, (-)-duryne (1) and (-)-durynes B-F (2-6), were isolated from the marine sponge Petrosia sp. Their structures were elucidated by NMR and tandem FABMS analyses. The positions of the olefinic bonds were confirmed by ozonolysis experiments, and the absolute configurations were determined by the modified Mosher's method. Compound 1 was(More)
Two cytotoxic peptides, yaku'amides A (1) and B (2), were isolated from the marine sponge Ceratopsion sp. Their planar structures were elucidated on the basis of spectroscopic data, whereas the absolute configurations were determined by a combination of the Marfey's analysis and dansylation analysis of the total and partial acid hydrolysis products. The(More)
We investigated microorganisms associated with a deep-sea sponge, Characella sp. (Pachastrellidae) collected at a hydrothermal vent site (686 m depth) in the Sumisu Caldera, Ogasawara Island chain, Japan, and with two sponges, Pachastrella sp. (Pachastrellidae) and an unidentified Poecilosclerida sponge, collected at an oil seep (572 m depth) in the Gulf of(More)
A cyclic peptide was isolated from the deep-sea marine sponge Discodermia japonica, and its NMR spectroscopic data were identical to those reported for cyclolithistide A, a known antifungal depsipeptide. However, the interresidue HMBC correlations suggested that the amino acid sequence was different from that of the original structure. Moreover,(More)
Spirastrellolides A (1) and B (3) have been isolated as free acids from a marine sponge Epipolasis sp. collected in the East China Sea. These compounds had been isolated from the Caribbean marine sponge Spirastrella coccinea after conversion to the methyl ester. We examined the cytotoxic activities of 1 and 3 and found that the activities of the free acids(More)
LCMS analysis of the extract and a cytotoxicity assay of the HPLC fractions generated from a small-scale extract of a Lipastrotethya sp. marine sponge demonstrated the presence of bisindole alkaloids that were associated with the cytotoxic activity. Two bisindole alkaloids tethered by a guanidino ethylthiopyrazine moiety, dragmacidins G (1) and H (2), were(More)
We have discovered new glycosylated fatty acid amides, stellettosides, from a Stelletta sp. marine sponge. They were detected through LC-MS analysis of the extract combined with the cytotoxicity assay of the prefractionated sample. Their planar structures were determined by analyses of the NMR and tandem FABMS data. Stellettosides A1 and A2 (1 and 2) as(More)
Cyclic peptides containing 5-hydroxytryptophan and thiazole moieties were isolated from the marine sponge Discodermia calyx collected near Shikine-jima Island, Japan. The structures of calyxamides A (1) and B (2), including the absolute configurations of all amino acids, were elucidated by spectroscopic analyses and degradation experiments. The structures(More)
Two new species of carnivorous sponges of the genus Abyssocladia are described. These sponges were collected from Myojin Knoll, Izu-Ogasawara (Izu-Bonin) Arc, in southern Japan. Detailed morphological observation based on specimen both in situ and preserved revealed functional differentiation of spicule distribution. Abyssocladia natsushimae sp. nov. is(More)
The purpose of this study was to develop a novel electrical retrieval method (ER method) for living sponge-associated microorganisms from marine sponges frozen at −80 °C. A −0.3-V vs. Ag/AgCl constant potential applied for 2 h at 9 °C induced the attachment of the sponge-associated microorganisms to an indium tin oxide/glass (ITO) or a gallium-doped zinc(More)