| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1994: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1993: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
I.The biologically rare D-aspartate was found in extracts of marine macroalgae. DL-Aspartate was isolated from the Phaeophyta, Hizikia fusiformis, By ion-exchange chromatography, and crystallized from aqueous ethanol. It was characterized by optical-rotatory-dispersion analysis and reversed phase HPLC analysis. The crystal consisted of equal amounts of D and I isomers. The presence of free D-aspartate was same method (HPLC) . Generally, Phaeophyta contained a high concentration of D-aspartate in contrast with the low concentration in Chlorophyta and Rhodophyta. Particularly in Costaria costata, Hizikia fusiformis and Sargassum yezoensis, belonging to those of L-aspartate.
II.D-Aspartate content in marine alga, Hizikia fusiformis, was determined in various seasons and different parts of the alga. D-Aspartate content varied seasonally ; it was high from late autumn to early spring and low in summer. The content also differed among various parts of the alga ; it was generally high in the adhesive root and main branch, and that in the blade was less than half that in the adhesive root. The content in the receptacle which was obtained from August sample was showed a level similar to that in the adhesive root or the main branch. From these results, we have assumed that free D-aspartate might play important roles in the early stage of growth of Hizikia fusiformis.
III.Occurrence of free D-alanine was verified in various marine macroalgae by the reversedphase HPLC analysis. The presence of free D-alanine was detected in 15species (54%) out of the total of 24 species of algae examined. The content was high in Hizikia fusiformis, Heterochordaria abietina, Sargassum nigrifolium of Phaeophyta (96,83 and 78nmol/g wet wt., respectively) . The ratio of D/L was different among algae species (0.03-0.49) , and there was no correlation between D-alanine content and D/L ratio.
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