[Ultrastructure of bacteriophages specific for Bacillus thuringiensis var. galleriae]

Fine structure of the phage specific for Bacillus thuringiensis var. galleriae was studied. The head of the phage is of the elongated hexagonal shape, 600 X 360 A. The tail is 400 X 40 A large and has a thickening in the basal part (70 X 120 A). A so-called "collar" structure is found at the site where the head joins the tail. This a disc-shaped plate with a diameter of 120 A and a hole in the centre; 12 fillaments are attached to it radially and terminated with tines. It is possible that the structure is necessary for adsorption of the phage on the cell.