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Diseases caused by malaria parasites and pathogenic bacteria were thought to be on the brink of eradication in the 1950-1960s, but they have once again become a serious threat to mankind as a result of the appearance of multidrug resistant strains. The spread of these multidrug resistant organisms has prompted a worldwide search for new classes of effective… (More)
Seven new long-chain acetylenic alcohols, strongylodiols D-J, were isolated from an Okinawan marine sponge of the genus Petrosia (Strongylophora). The structures of these compounds were elucidated on the basis of the results of spectroscopic analysis and chemical reaction. Analysis of the MNA esters of the acetylenic alcohols disclosed that these compounds… (More)
Bioconversion (biotransformation) experiments on arenes (aromatic compounds), including various tricyclic fused aromatic compounds such as fluorene, dibenzofuran, dibenzothiophene, carbazole, acridene, and phenanthridine, were done using the cells of Escherichia coli transformants expressing several arene dioxygenase genes. E. coli carrying the phenanthrene… (More)
Seven new marine diterpenoids having a cembrane skeleton were isolated from the Okinawan soft coral Clavularia koellikeri. Their structures were determined based on the results of spectroscopic analysis and chemical conversions. Compound 1 showed cytotoxic activity against human colorectal adenocarcinoma cells (DLD-1, IC(50) 4.2 g/mL) and strong growth… (More)
We study the electrical conductivity problem of DNA, applying the Holstein's polaron model to a double strand of DNA. We show that the Holstein's polarons act as donors and acceptors in DNA and that the existence of such donors and acceptors provides us the extrinsic semiconductor character of DNA. This character of DNA may explain with a unified point of… (More)
A new bisabolane-type sesquiterpenoid, (E)-3-isocyanobisabolane-7,10-diene (1), and a new epidioxyergostane-type steroid, 9(11)-dehydroaxinysterol (2), were isolated from the Okinawan sponge of the genus Axinyssa. Their structures were elucidated based on the results of spectroscopic analysis and chemical conversion. Epidioxysterol 2 was found to show… (More)
To investigate the localization of clavulones (CV), prostanoids with antitumor activity, in the Okinawan soft coral Clavularia viridis, we developed a method for the isolation of Symbiodinium cells from the coral, i.e., treatment of a coral homogenate with a protease, pronase E, and a detergent, Nonidet P-40. The conditions for the treatment were optimized… (More)
Chemical investigation of the Okinawan soft coral Clavularia koellikeri resulted in the isolation of two new cembrane diterpenoids (1 and 2) and one new dollabelane diterpenoid, 3. Their structures were determined on the basis of the results of spectroscopic analysis. Compounds 1 and 3 were examined for in vitro growth-inhibition effects toward tumor cells.
Five new halogenated prostanoids 1-4 and 6 were isolated from the Okinawan soft coral Clavularia viridis. The gross structure of 1 was elucidated mainly on the basis of NMR spectral data. The relative and absolute configurations were determined by analysis of NOESY and CD data, chemical conversion, and the modified Mosher's method. The structures of 2-4 and… (More)
A novel terpenoid-related compound, stolonilactone (1), was isolated from the Okinawan soft coral Clavularia koellikeri. The structure of 1 was elucidated on the basis of spectroscopic analysis. A possible biogenesis of 1 through the [4 + 2]-cycloaddition of a trisnorsesquiterpenoid-type diene and a cembranolide-type dienophile is proposed.