| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1986: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1985: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
Ascidians are known to accumulate very large amounts of vanadium within their tissues. They are, therfore, thought to be the best material to use in order to examine the function of vanadium. We have already determined the vanadium contents of 15 species of solitary ascidians, mainly by neutron activation analysis. The highest value of vanadium was obtained from blood cells of Asicia ahodori (21 ug vanadium/mg dry meight).
However, the blood cells are generally classified into 7 types in this species. Which of these cell types are involved in the accumulation of vanadium from sea water is controversial.
The present project was, therefore, designed to determine the distribution of vanadium in each of these blood cell types using a new technique for cell fractionation in Ficoll density gradients, followed by neutron activation analysis for vanadium and ESR spectra of oxovanadium ion.
Consequently, although a subpopulation of morula cells, originally termed vanadocytes, could be obtained with above 90% purity, it contained little vanadium. Instead of it, a subpopulation of signet ring cells distributed in the lowest layer in the Ficoll density gradients contained the highest amount of vanadium (7 ng vanadium/1000 cells). Thus, it has been found that the signet ring cells are primary blood cells that accumulate vanadium in Ascidia ahodori. Moreover, ESR spectra have revelaed that vanadyl ion ( <VO^(2+)> ), vanadium in oxidation state IV, was detected in the cells and bound with some low-molecules through its oxygen donors.
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