Separation of the ascidian blood cells containing a large amount of vanadium and their accumulating mechanism of this element

众所周知，海鞘在其组织内积累了大量的钒。因此，它们被认为是用于研究钒的功能的最佳材料。我们主要用中子活化法测定了15种海鞘的钒含量。血细胞中钒含量最高的是Asicia ahodori（21 μ g/mg干重），但血细胞一般分为7种类型。这些细胞类型中的哪一种参与了海水中钒的积累是有争议的。因此，本项目的目的是确定钒在这些血细胞类型中的分布，使用Ficoll密度梯度中的细胞分级的新技术，然后进行钒的中子活化分析和氧钒离子的ESR光谱。因此，尽管桑椹胚细胞的亚群，原称钒细胞，可获得纯度在90%以上，含钒量极低。相反，分布在Ficoll密度梯度最低层的印戒细胞亚群含有最高量的钒（7 ng钒/1000个细胞）。因此，已经发现印戒细胞是在阿霍氏海鞘中积累钒的初级血细胞。ESR谱表明，细胞内存在钒氧离子（<VO^（2+）>），即氧化态为IV的钒，并通过氧供体与一些小分子结合。

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.