MEASUREMENT OF SOFT-X-RAY ABSORPTION-SPECTRA AND ELEMENTAL ANALYSIS IN LOCAL REGIONS OF MAMMALIAN-CELLS USING AN ELECTRONIC ZOOMING TUBE

Direct measurement of absorption spectra for minute areas (2 mu m x 2 mu m) in a dried mammalian cell was attempted using X-ray contact imag es of a whole cell. The wavelength region used ranged from 1.5 to 10 n m covering the absorption edges of the major cellular elements. The me asurements were achieved taking advantage of synchrotron radiation as a tuneable light source and an electronic zooming tube as an X-ray det ector with a high spatial resolution. The spectra in every intracellul ar area exhibited marked absorption changes at the absorption edges of carbon, nitrogen and oxygen, while minor but significant changes far iron and calcium were observed, particularly in the cytoplasmic areas. These results reveal the different spatial distributions of the const ituent elements in a cell.