Research Project
3431302
Calculations havd shown that X-ray microscopy can be used to image both thick and wet specimens. This would be a significant advance over electron microscopy, which requires thin, dry specimens. Furthermore, the very short (less than 100ns) pulse of the flash soft X-ray sources can freeze the motion of live cells. This is not possible with synchrotron or electron impact sources, whose long exposure times produce blurred images. Exploitation of flash soft X-ray sources for X-ray microscopy of live biological specimens has been hampered by doubts concerning the consistent quality and biological usefulness of X-ray lithographic images of thick specimens such as whole cells. Given these doubts and the relative expense of the high technology pulsed plasma X-ray sources, funding for a feasibility demonstration has not been forthcoming. We propose an investigation to demonstrate that flash soft X-ray microscopy will result in useful and perhaps unique biological information. The investigation will consist of a comparative analysis of X-ray and electron images of several series of specimens of Drosophila salivary gland. The dried specimens will include both thick and thin sections, with the polytene chromosomes in both stained and unstained states. Finally, thick hydrated specimens will be imaged and analyzed. This will establish the validity of X-ray microscopy for observation of microstructures and will provide a direct basis for comparison should novel structures be observed in the X-ray images.
