BACTERIOPHAGE AND ASSOCIATED POLYSACCHARIDE DEPOLYMERASES - NOVEL TOOLS FOR STUDY OF BACTERIAL BIOFILMS

Bacteriophage for three representative strains of Gram-negative biofil m bacteria have proved to be of widespread occurrence. Lyric bacteriop hage have been isolated from local sewage for the bacterium 1.15, an e xopolysaccharide (EPS)-producing pseudomonad found originally as a com ponent of biofilms in a local river, and for two Enterobacter agglomer ans strains from industrial biofilms. Representative examples of all t hree bacteriophage possess a relatively low burst size and on solid me dia, exhibit very large plaques surrounded by a wide halo (5-20 mm) in dicative of polysaccharide depolymerase action. The bacteriophage are thus similar to other viruses for EPS-producing bacteria in inducing t he synthesis of enzymes degrading the polymers which occlude the bacte rial cell surface. In each preparation, the polysaccharase activity wa s associated both with sedimented phage particles and with the superna te of bacterial lysates. The enzymes have been partially purified and used to prepare polysaccharide digests in which the major products fro m each polysaccharide are the presumed repeat units of the polymers or oligomers of these. The soluble phage enzymes each degrade their subs trate by acting as endo-glycanohydrolases. The phage and their associa ted enzymes thus provide very useful highly specific tools for studies of biofilms incorporating the bacterial host strains. Their potential applications in studies on bacterial biofilms are discussed.