title: Physicochemical properties of PM-factor, a surface-active agent produced by Pseudomonas marginalis.
abstract: An extracellular surface-active agent, PM-factor, was obtained by high-speed centrifugation from the culture broth of Pseudomonas marginalis PD-14B. PM-factor exhibited emulsifying activity on a broad spectrum of hydrocarbon liquids, including aromatics, aliphatics, crude oil, and creosote. The factor appeared as ball-shaped particles of varying diameter when examined by electron microscopy (0.16-1.4 microns). Gel filtration chromatography demonstrated a high molecular mass of the factor (> 10(6) Da). The ultraviolet absorption spectrum manifested a peak in the region 200 nm rather in the region 260-280 nm. Amino acid analysis showed a very low amount of aromatic amino acids residues in the protein moiety of PM-factor. The presence of 3-deoxy-D-mannooctulosonic acid, heptose, hexosamine, phosphorus, and 3-hydroxy fatty acid indicated that PM-factor contained lipopolysaccharide. The emulsifying activity of PM-factor was inhibited strongly by mercuric chloride and moderately by EDTA. Polymyxin B, Ca2+, and Mg2+ markedly stimulated the factors emulsifying activity. Roles of the bioemulsifier in the functioning of P. marginalis as a plant pathogen and in bioremediation are discussed.
authors.affiliation: Department of Biology, University of Waterloo, ON, Canada.
authors.forename: G
authors.initials: G
authors.lastname: Burd
authors.forename: O P
authors.initials: OP
authors.lastname: Ward
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D011549:Pseudomonas / Q000737:chemistry*; D017421:Sequence Analysis
chemical_list: D001425:Bacterial Outer Membrane Proteins