Changes in nucleus and surface of Lepidoptera cells cultivated in vitro after infection with nuclear polyhedrosis viruses (Autographa californica).

Changes in cell nuclei after infection of Lepidoptera cells, demonstrated by means of the fluorochrome "33 258H", permit the observation of virus DNA synthesis in a light microscope. Parallel occurring changes in cell surfaces, analysed in a scanning electron microscope, also permit an exact differentiation between infected and non-infected cells.