J. Phys. IV France 104 (2003) 333
DOI: 10.1051/jp4:200300093

Local distribution of vanadium in the living blood cells of ascidians by fluorescence scanning X-ray microscopy ID21 at ESRF

K. Takemoto¹, T. Ueki², B. Fayard³, A. Yamamoto⁴, M. Salomé³, S. Scippa⁵, J. Susini³, T. Uyama², H. Michibata² and H. Kihara<sup>1

1</sup>  Department of Physics, Kansai Medical University, Uyamahigashi 18-89, Hirakata, Osaka 573-1136, Japan
²  Marine Biological Laboratory, Graduate School of Science, Hiroshima University, Hiroshima 722-0073, Japan
³  European Synchrotron Radiation Facility, ESRF, BP. 220, 38043 Grenoble cedex, France
⁴  Department of Physiology-I, Kansai Medical University, Fumizono 10-15, Moriguchi, Osaka 570-8506, Japan
⁵  Department of Genetics, General and Molecular Biology, Faculty of Science, University of Naples, via Mezzocannone 8, 80134 Naples, Italy and Stazione Zoologica "Anton Dohrn", Villa Comunale, 80121 Naples, Italy

Abstract
Blood cells of ascidians (tunicates) are known to accumulate high levels of vanadium selectively from sea water [1]. It has long been extensively studied how much vanadium is accumulated, which organ participate in the accumulation of vanadium, and what is the route of vanadium accumulation. However, they are not yet revealed completely. Micro-XANES is a powerful tool to investigate micro-distribution of chemical species of a given element. Fluorescence scanning X-ray microscope at ESRF (ID21), covering an energy range from 2 to 8 keV, has the capability of investigating chemical states of vanadium, sulfur, magnesium and calcium. In the present study, we have applied this X-ray scanning microscope in fluorescence mode to elucidate the distribution of vanadium in living ascidian blood cells. Using a cryogenic sample holder, local XANES spectra was also taken successfully. The valence of the vanadium in the cellis +3 and +4, judging from XANES spectra.

© EDP Sciences 2003