Vanadocytes, Cells hold the Key to Resolving the Highly Selective Accumulation and Reduction of Vanadium in Ascidians
Use this link to cite this item : https://ir.lib.hiroshima-u.ac.jp/00000022
ID | 22 |
file | |
creator |
Michibata, Hitoshi
Uyama, Taro
Kanamori, Kan
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subject | Ascidian
Vanadium
Accumulation
Reduction
pH
Vacular H+-ATPase
Monoclonal antibody
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NDC |
Biology
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abstract | Since Henze discovered vanadium in the blood (or coelomic) cells of an ascidian in 1911, this unusual phenomenon has attracted the interest of many investigators. The highest concentration of vanadium (350 mM) in the blood cells of Ascidia gemmata, which belongs to the suborder Phlebobranchia, is 107 times higher than that in sea water. Of the approximately ten types of blood cells, a combination of cell fractionation and neutron-activation analysis revealed that the signet ring cells were the true vanadocytes. In the vanadocytes, 97.60f the vanadium is in the +3 oxidation state (III). The extremely low pH of 1.9 found in vanadocytes suggests that protons, concentrated by an H+-ATPase, might be linked to the accumulation of vanadium energetically. The antigen recognized by a monoclonal antibody, S4D5, prepared to identify vanadocytes, was determined to be 6-PGDH in the pentose phosphate pathway. NADPH produced in the pentose phosphate pathway in vanadocytes is thought to participate in the reduction of vanadium(V) to vanadium(IV). During embryogenesis, a vanadocyte-specific antigen first appears in the body wall at the same time as significant accumulations of vanadium become apparent. Three different vanadium-associated proteins (VAPs) were extracted from the blood cells of vanadium-rich ascidians. These are 12.5, 15, and 16 kDa in size and are associated with vanadium in an approximate ratio of 1:16. The cDNA encoding the 12.5 and 15 kDa VAPs was isolated and the proteins encoded were found to be novel. Further biochemical and biophysical characterization of the VAPs is in progress.
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journal title |
Microsopy research and technique
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volume | Volume 56
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start page | 421
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end page | 434
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date of issued | 2002
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publisher | Wiley-Liss, Inc.
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issn | 1059-910X
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publisher doi | |
pubmed id | |
language |
eng
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nii type |
Journal Article
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HU type |
Journal Articles
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DCMI type | text
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format | application/pdf
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text version | author
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rights | Copyright (c) 2002 Wiley-Liss, Inc.
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relation is version of URL | http://dx.doi.org/10.1002/jemt.10042
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department |
Graduate School of Science
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