Enzymic Activity of Bacteriophage-Culture Lysates

Abstract

Filtered phage lysates of a K. pneumoniae, type A culture (strain 108M) contain a lysin (designated C lysin) that decapsulates type A Friedlander cells. Filtrates formalinized to 0.5% or heated to 70 C for 30 min. lose their lytic activity but retain the capsule dissolving power. Passage of filtrate through a suitably graded collodion membrane removes the phage but not the lysin. Such ultrafiltrates are nontoxic for the Klebsiella culture. C lysin filtrates produce a marked thinning and reduction in opacity of adult agar plate growth films of strain 108M, and lysin concn. is titrated by determining the highest dilution of filtrate capable of producing this clearing after 18 hrs. incubation at 37 C. Lysin treatment of living or killed 108M cultures results in loss of serological type specificity and marked reduction in cell volume. C-treated cells fail to elicit the production of type specific antibodies in the rabbit. 108M cultures growing in the presence of lysin are rendered susceptible to a phage active only against a nonencapsulated culture variant of this bacterial strain. The lysin apprears to be type specific in its capsule dissolving action. It liberates SSS from the bacterial cells and does not cause chemically prepared SSS to lose its haptenic properties. C lysin is destroyed by 85 C for 10 min. and is rapidly inactivated by strong acid and alkali. It is nondialyzable and is precipitated by (NH4)2SC4, acetone and alcohol. It is considered to be an enzyme.