Localizing the Chemical Forms of Sulfur in Vivo Using X-ray Fluorescence Spectroscopic Imaging: Application to Onion ( Allium cepa ) Tissues
2009; American Chemical Society; Volume: 48; Issue: 29 Linguagem: Inglês
10.1021/bi900368x
ISSN1943-295X
AutoresIngrid J. Pickering, Eileen Yu Sneeden, Roger C. Prince, Eric Block, Hugh H. Harris, Gregory Hirsch, Graham N. George,
Tópico(s)Genomics, phytochemicals, and oxidative stress
ResumoSulfur has a particularly rich biochemistry and fills a number of important roles in biology. In situ information on sulfur biochemistry is generally difficult to obtain because of a lack of biophysical techniques that have sufficient sensitivity to molecular form. We have recently reported that sulfur K-edge X-ray absorption spectroscopy can be used as a direct probe of the sulfur biochemistry of living mammalian cells [Gnida, M., et al. (2007) Biochemistry 46, 14735−14741]. Here we report an extension of this work and develop sulfur K-edge X-ray fluorescence spectroscopic imaging as an in vivo probe of sulfur metabolism in living cells. For this work, we have chosen onion (Allium cepa) as a tractable model system with well-developed sulfur biochemistry and present evidence of the localization of a number of different chemical forms. X-ray absorption spectroscopy of onion sections showed increased levels of lachrymatory factor (LF) and thiosulfinate and decreased levels of sulfoxide (LF precursor) following cell breakage. In intact cells, X-ray fluorescence spectroscopic imaging showed elevated levels of sulfoxides in the cytosol and elevated levels of reduced sulfur in the central transport vessels and bundle sheath cells.
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