T _i and λ Phage Adsorption on Protoplast-like Bodies of Escherichia coli

Abstract

DURING the past few years, methods have been developed for preparing spherical units of Gram-negative bacteria such as E. coli, which have often been described as ‘large bodies’ or ‘protoplasts’. Unlike the protoplasts of Gram-positive bacteria, these spherical forms are also very sensitive to osmotic change. Whereas it can be shown by various methods that the cell wall is removed in the case of B. megatherium, this has not been proved conclusively for the spherical forms of E. coli. Since the cell wall of E. coli, unlike that of Gram-positive bacteria, contains a lipoprotein component as well as lipo-polysaccharide¹ and at least four of five methods of preparation for spherical forms involve only poly-saecharides, it is very probable that the spherical forms of E. coli are surrounded by cell-wall remains. If this is really the case, we may assume that these forms adsorb at least some of those phages, towards which the rod-shaped, normal cell is sensitive.