title: Polysaccharides cellulose, poly-beta-1,6-n-acetyl-D-glucosamine, and colanic acid are required for optimal binding of Escherichia coli O157:H7 strains to alfalfa sprouts and K-12 strains to plastic but not for binding to epithelial cells.
abstract: When Escherichia coli O157:H7 bacteria are added to alfalfa sprouts growing in water, the bacteria bind tightly to the sprouts. In contrast, laboratory K-12 strains of E. coli do not bind to sprouts under similar conditions. The roles of E. coli O157:H7 lipopolysaccharide (LPS), capsular polysaccharide, and exopolysaccharides in binding to sprouts were examined. An LPS mutant had no effect on the binding of the pathogenic strain. Cellulose synthase mutants showed a significant reduction in binding; colanic acid mutants were more severely reduced, and binding by poly-beta-1,6-N-acetylglucosamine (PGA) mutants was barely detectable. The addition of a plasmid carrying a cellulose synthase gene to K-12 strains allowed them to bind to sprouts. A plasmid carrying the Bps biosynthesis genes had only a marginal effect on the binding of K-12 bacteria. However, the introduction of the same plasmid allowed Sinorhizobium meliloti and a nonbinding mutant of Agrobacterium tumefaciens to bind to tomato root segments. These results suggest that although multiple redundant protein adhesins are involved in the binding of E. coli O157:H7 to sprouts, the polysaccharides required for binding are not redundant and each polysaccharide may play a distinct role. PGA, colanic acid, and cellulose were also required for biofilm formation by a K-12 strain on plastic, but not for the binding of E. coli O157:H7 to mammalian cells.
authors.affiliation: Department of Biology, Coker Hall, University of North Carolina, Chapel Hill, NC 27599-3280, USA. ann_matthysse@unc.edu
authors.forename: Ann G
authors.initials: AG
authors.lastname: Matthysse
authors.forename: Rajendar
authors.initials: R
authors.lastname: Deora
authors.forename: Meenu
authors.initials: M
authors.lastname: Mishra
authors.forename: Alfredo G
authors.initials: AG
authors.lastname: Torres
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000502:physiology; D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development; D002482:Cellulose / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000382:microbiology*; D048168:Escherichia coli K12 / Q000235:genetics / Q000502:physiology*; D019453:Escherichia coli O157 / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D005816:Genetic Complementation Test; D005964:Glucosyltransferases / Q000235:genetics; D000455:Medicago sativa / Q000382:microbiology*; D009154:Mutation; D018517:Plant Roots / Q000382:microbiology; D010957:Plasmids; D010969:Plastics; D011134:Polysaccharides / Q000235:genetics / Q000378:metabolism*; D016962:Sinorhizobium meliloti / Q000235:genetics / Q000502:physiology; D047071:beta-Glucans / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D010969:Plastics; D011134:Polysaccharides; D047071:beta-Glucans; C505465:poly-N-acetyl-1-6-glucosamine; D002482:Cellulose; C004275:colanic acid; D005964:Glucosyltransferases; C478648:cellulose synthase