Bacteriophage-derived enzyme that depolymerizes the alginic acid capsule associated with cystic fibrosis isolates of Pseudomonas aeruginosa

• Published in: Journal of applied microbiology 2010-02, Vol.108 (2), p.695-702
• Main Authors: Glonti, T, Chanishvili, N, Taylor, P.W
• Format: Article
• Language: English
• Subjects: alginate lyase; alginates; Alginates - metabolism; alginic acid; Bacteria; Bacterial Capsules - metabolism; bacteriophage; Bacteriophages - enzymology; Biofilms; Biological and medical sciences; Cystic Fibrosis - microbiology; exopolysaccharide depolymerase; Fundamental and applied biological sciences. Psychology; Glucuronic Acid - metabolism; Hexuronic Acids - metabolism; Microbiology; Podoviridae; Pseudomonas aeruginosa; Pseudomonas aeruginosa - virology; Pseudomonas Infections - microbiology; Viral Plaque Assay
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/j.1365-2672.2009.04469.x

To identify enzymes associated with bacteriophages infecting cystic fibrosis (CF) strains of Pseudomonas aeruginosa that are able to degrade extracellular alginic acids elaborated by the host bacterium. Plaques produced by 21 Ps. aeruginosa-specific phages were screened for the presence of haloes, an indicator of capsule hydrolytic activity. Four phages produced haloed plaques, and one (PT-6) was investigated further. PT-6 was shown by electron microscopy to belong to Podoviridae family C1, to reduce the viscosity of four alginate preparations using a rolling ball viscometer and to release uronic acid-containing fragments from the polymers, as judged by spectrophotometry and thin layer chromatography. The alginase was partially purified by gel filtration chromatography and shown to be a 37 kDa polypeptide. Infection of CF strains of Ps. aeruginosa by phage PT-6 involves hydrolysis of the exopolysaccharide secreted by the host. The alginase produced by PT-6 has the potential to increase the well-being of CF suffers by improving the surface properties of sputum, accelerating phagocytic uptake of bacteria and perturbing bacterial growth in biofilms.