Yoshiro Matsuda

Development and application of an effective detection method for fish plasma vitellogenin induced by environmental estrogens

Vitellogenin is a protein induced by estrogens, including environmental chemicals with estrogenic activity. To measure the effects of environmental estogens, we developed an effective and rapid one-step method of detecting and purifying fish plasma vitellogenin using a high-performance anion-exchange chromatography column, POROS-HQ. Vitellogenin in a plasma of estradiol-treated male fish (mummichog and red sea bream) was eluted as a single peak with a retention time of 10 minutes from the column, which gives an almost pure preparation as assessed by SDS-PAGE. The lowest detectable amount of vitellogenin was 2 μg per assay. The method was used to analyze the plasma vitellogenin level of aquacultured red sea breams caught in August, when the spawning season is over, and usually no vitellogenin is detected in either females or males, physiologically. However, the data showed that in addition to a few females, some male fish synthesized vitellogenin, suggesting that some chemicals or unknown factors with estrogenic activity have induced fish in the ocean to produce vitellogenin.

Novel synthesis of methine dyes absorbing in the near-infrared region

Abstract By reaction of 2-(1-cyano-1-methylthio)methyleneindan-1,3-dione ( 2 ) with nucleophiles, the corresponding substituted compounds ( 10–16 ) as typical donor-acceptor chromogens were obtained. Novel methine dyes ( 24,25 ) absorbing in the near-IR region (650–850 nm) were synthesized by condensation of 16 and malononitrile with TiCl 4 and pyridine.

One step synthesis of heteropolycycles, indolizinoquinolizines by the reaction of either pyridylketene dithioacetal with pyridinium salt or pyridiniumketene dithioacetal with pyridylacetonitrile

Abstract The heteropolycycles, indolizinoquinolizines (7, 8, 20) were obtained by the reaction of either pyridylketene dithioacetal (2) with two molar equivalents of pyridinium salts (4a–c) or pyridiniumketene dithioacetal (19) with two molar equivalents of pyridylacetonitrile (3) in the presence of triethylamine.