Distinct Slime Polysaccharide Depolymerases of Bacteriophage-Infected Pseudomonas aeruginosa: Evidence of Close Association with the Structured Bacteriophage Particle

Abstract

Five new polysaccharide depolymerases were isolated from cultures of Pseudomonas aeruginosa infected with phages 6, 7, 8, 9, and 10. The production of enzyme paralleled the release of phage. Depolymerase associated with phage 8 was active on slime polysaccharide A, whereas depolymerases associated with phages 6, 7, 9, and 10, like pseudomonas phage 2, hydrolyzed slime polysaccharide B. None of the depolymerases was active on slime polysaccharide C. Despite exhaustive purification, depolymerase activity was found to band with the phage particles at a density of 1.49 to 1.51 g/mI in a density gradient composed to cesium chloride. These results suggest that the depolymerases are firmly bound to the phage particles.

Purification and Chemical Composition of the Protective Slime Antigen of Pseudomonas aeruginosa

“…The clinical importance of the slime layer has been emphasized by the work of several investigators, and has been implicated in resistance to chemotherapy (12), toxicity, and pathogenicity (22), and as a protective antigen in experimental infection (1,2,22). More recently, it has been considered as a factor influencing the life cycle of bacteriophage (5)(6)(7).…”

“…Although studies regarding the chemical composition of the slime of P. aeruginosa appear to be confusing and contradictory (11), evidence has been presented to indicate that variations in the composition of slime may exist from one strain to another (6,7,22). Eagon (16) reported that the slime polysaccharide was com-posed chiefly of mannose and nucleic acids, mostly deoxyribonucleic acid (DNA), and small amounts of protein.…”

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

“…Origin of phage 8 and its depolymerase. The attachment of phage 8 to P. aeruginosa strain EI and the phage-receptor properties of the slime GLP layers of strains BI and EI have been reported (4,7). Strain 1234 (8), which carries phage 8 as a prophage, provided the opportunity to observe the kinetics of depolymerase synthesis relative to infective phage replication.…”

“…Two organisms used for this study, P. aeruginosa strains El (Fisher serotype 6) and 1234(8), were originally isolated from clinical specimens. They and the temperate bacteriophage 8 have been described previously (4). Lysogenic and phage 8-resistant strains were isolated as colonies surviving exposure to phage 8 by the procedures of Adams (1).…”

“…Phage 8 replicates in strain EI with the production of a depolymerase that hydrolyzes the extracellular slime of strain El. On confluent lawns of strain EI the depolymerase produces a halo around the plaques of phage 8 (4). The halo provided a useful marker for the initial sorting of phage 8-resistant isolates into lysogenic and nonlysogenic.…”