Bacteriophage inhibition by extracts from phage-insensitive bacteria of the genusPseudomonas

Abstract

1. An electrophoretically homogeneous antigen preparation extracted from a strain (LII) ofPseudomonas aeruginosaby trichloracetic acid inhibits four phages active against this strain, and two phages (5 and 14) to which it is resistant but which attack a mutant strain LIII–3 bi.2. An extract prepared in the same way from strain LIII–3 bi has no antigenic or inhibitory properties. Lysis of LIII–3 bi organisms by chloroform, however, yields a potent inhibitor active against several phages.3. TCA extracts from immunologically distinctPs. strains AII, BII and GII also inhibit phages 5 and 14 to which these strains are resistant.4. The effect of a third phage (13) onPs. LIII–3 bi is activated by the extract from strain LII which normally inhibits phages 5 and 14. Prolonged contact with very dilute solutions of the extract also causes activation of phage 5. Activation of phage 14 has not been observed.5. The above findings are discussed in relation to current theories of phage action and phage inhibition.