Bacteriophage attachment to the S-layer proteins of the mosquito-pathogenic strains ofBacillus sphaericus

The linearly arrayed surface layer proteins found on the mosquito-pathogenic strains ofBacillus sphaericus function as the site of bacteriophage attachment for the ten lytic bacteriophages used in a bacteriophage typing scheme. Attachment to the surface layer proteins was demonstrated by the ability to block bacteriophage binding with antisera and the ability of the purified proteins to neutralize bacteriophage. Bacteriophage-resistant mutants have modified surface proteins that are less able to neutralize bacteriophages than is the protein of the parent strain. No evidence was obtained that sugar residues play a part in bacteriophage attachment. Phage neutralization by surface proteins from strains that do not serve as host to the phage indicates that, although strains in each phage group have a unique surface protein, the proteins do not determine the phage groups.