Nucleic acid molecules: new microdiffusion technique for visualization.

A microdiffusion technique, developed for visualization of nucleic acid molecules in the electron microscope, requires less than 0.01 microgram of nucleic acid. Although originally developed for free nucleic acids, the method can be applied to virion suspensions for direct visualization of their genomes; less than 10(10) virions per milliliter are required. Results agree well with those yielded by the diffusion technique of Lang, Kleinschmidt, and Zahn.