Abstract
The envelope system as seen in the thin section of the cell of Lactobacillus casei ATCC 27092 was of the multi-layered type. The transverse section of the isolated cell walls had a homogeneous appearance with a width of about 20nm. The cell wall preparations were considered to correspond to the surface layer in the thin section of whole cells. Electron microscopic examination of the mixtures of PL-1 phages and cell walls after fixation with osmic acid revealed that all the phages were adsorbed to cell walls in a tail-first orientation and that the adsorbed phages were intact. When the adsorption mixtures were not fixed with osmic acid, the adsorbed phages were eluted as infective virions by centrifuging and resuspending in fresh medium. In a control where the phages were mixed with the cell walls isolated from a phage-resistant strain named K-12, the phages showed no tendency to bind to the cell walls. Thin section of osmic acid-treated mixtures of phages and cell walls confirmed that the phages bound by their tail tip to the one side of cell wall preparations.
