Phage-related surface modifications of Pseudomonas aeruginosa: effects on the biological activity of viable cells

Abstract

Lysogenic [EI(8)3] and phage 8-resistant mutant (EI/8S17) strains of Pseudomonas aeruginosa EI were isolated. Besides lacking the capacity to adsorb phage 8, strains EI(8)3 and EI/8s17 did not contain surface substrate for the depolymerase that is produced de novo when phage 8 infects wild-type strain. EI. The glycolipoprotein (GLP) in the wild type contains phage 8 receptors and surface substrate for the depolymerase, as well as possesses characteristics of a virulence factor; therefore, the chemical and biological characteristics of the derived strains were investigated. The neutral-sugar, amino sugar, and protein content of the GLPs from the derived strains differed quantitatively from that of the wild type. In spite of some cross-reactivity, the GLPs from all strains were antigenically distinct in the indirect hemagglutination inhibition test. In mice, the toxicity of the GLP from strain EI(8)3 equaled that of the wild type, but the GLP of strain EI/8s17 was threefold less toxic. Significantly fewer viable EI(8)3 cells were required for the mouse 50% lethal dose than for the cells of either the wild type or the phage-resistant mutant.