Development and Applications of Quantitative X - Microscopy with Chemical Sensitivity
X-ray microscopy has been developed to image biological samples with a resolution intermediate between visible light and electron microscopes. Interest in distinguishing different molecules using x-ray microscopy has motivated the effort to combine x-ray microscopy with x-ray absorption near-edge spectroscopy (XANES). This thesis includes three projects. The major part concerns the development and applications of XANES microscopy to quantitatively map DNA and proteins. The two other parts are image formation and image contrast enhancement through deconvolution and the use of carbon-XANES to study soft x-ray irradiation induced chemistry in PMMA (a widely used x-ray resist). For the major part of the thesis, XANES microscopy was applied to examine the content and distribution of DNA and protein in mature sperm cells. Sperm nuclei from five different species of mammals were examined, species chosen for analysis because their sperm contains markedly different proportion of protamine 1 and protamine 2 (which are the basic DNA packing proteins in sperm). This work provides new information about composition and structure of sperm chromatin by showing that the protein to DNA ratio in sperm nuclei is not strongly species dependent.
- Pub Date:
- January 1995
- XANES SPECTROSCOPY;
- Physics: Radiation; Biology: Cell