CELLULAR STRUCTURE AS REVEALED BY ULTRAVIOLET PHOTOLYSIS AND THE ELECTRON MICROSCOPE

Abstract

Bacterial and yeast cells were exposed to a quartz Hg-vapor lamp at a distance of 12 cm., either dry or on collodion-coated glass slides or in suspension in a quartz cell. The irradiation gradually photolysed cellular material. This rendered the cells more transparent to the electron beam and made possible the demonstration of internal structure. After 3 hrs. irradiation in the dry state, cells of Bacillus subtilis show clear nucleus-like bodies. After 24 hrs., these bodies disappear. Irradiation of B. subtilis in suspension results in extension and flattening of the cell wall which then contains a small opaque rod. Irradiation of Saccharomyces cerevisiae in the dry state produced electron micrographs demonstrating the "dancing body," the "nuclear membrane" surrounding it, another membrane surrounding the latter, and the cell wall surrounding the whole. The "nuclear vacuole" still contained feulgen-positive material after irradiation. Both the cell wall and the membrane of the "nuclear vacuole" stained with cell wall stains.