CRITICAL-POINT MOUNTING OF KINETOPLAST DNA FOR ATOMIC-FORCE MICROSCOPY

Atomic force microscope (AFM) images of intact kinetoplast DNA were ob tained from samples prepared utilizing critical point drying. These im ages are compared with AFM images obtained using conventional methods for DNA deposition. Although the images obtained on chemically pretrea ted mica show more details than on unmodified mica, images obtained wi th critical point drying were superior. Kinetoplast networks with expe cted sizes and structures were routinely observed with critical point drying. The resolution of individual strands of DNA was greatly improv ed, and image artifacts associated with air dried samples were elimina ted. Samples prepared using mildly sonicated kinetoplast DNA show isol ated minicircles.