Abstract
Comparative observations were made by electron microscopy and light microscopy with adjoining sections prepared serially from the same HeLa cell infected with adenovirus type 12. Eosinophilic granules uniformly distributed in the nucleus at the initial stage of virus infection proved to be condensed masses of karyoplasm and subsequently tne peripheral region of the nucleus became more transparent with a deep purplish red inclusion body in the center. The inclusion body was shown to be a conglomeration of eosinophilic structureless granules, karyoplasm and crystalline arranged virus particles. The inclusions gradually became condensed as infection advanced, and finally the entire nucleus became transparent, containing a few electron dense structureless eosinophilic granules with smooth margin, sparsely scattered. Since these granules increased in number and size along with the increase in the number of virus particles, they are regarded as metabolic products accompanying virus replication. The densely stained inclusion body in the center of nucleus contained groups of crystalline arranged virus particles and the transparent portion was replete with numerous virus particles in noncrystalline arrangement. In either arrangement, the virion measured 65-70mμ in diameter, consisting of an electron dense core and a limiting membrane, which corresponded capsid shown by negative staining. The virion is confirmed to be of icosahedron.
