title: Pectic oligosaccharide structure-function relationships: Prebiotics, inhibitors of Escherichia coli O157:H7 adhesion and reduction of Shiga toxin cytotoxicity in HT29 cells.
abstract: Shiga toxin (Stx)-producing, food-contaminating Escherichia coli (STEC) is a major health concern. Plant-derived pectin and pectic-oligosaccharides (POS) have been considered as prebiotics and for the protection of humans from Stx. Of five structurally different citrus pectic samples, POS1, POS2 and modified citrus pectin 1 (MCP1) were bifidogenic with similar fermentabilities in human faecal cultures and arabinose-rich POS2 had the greatest prebiotic potential. Pectic oligosaccharides also enhanced lactobacilli growth during mixed batch faecal fermentation. We demonstrated that all pectic substrates were anti-adhesive for E. coli O157:H7 binding to human HT29 cells. Lower molecular weight and deesterification enhanced the anti-adhesive activity. We showed that all pectic samples reduced Stx2 cytotoxicity in HT29 cells, as measured by the reduction of human rRNA depurination detected by our novel TaqMan-based RT-qPCR assay, with POS1 performing the best. POS1 competes with Stx2 binding to the Gb3 receptor based on ELISA results, underlining the POS anti-STEC properties.
authors.affiliation: Department of Plant Biology and Pathology, Rutgers, the State University of New Jersey, 59 Dudley Road, New Brunswick, NJ 08901, USA. Electronic address: di@aesop.rutgers.edu.
authors.forename: Rong
authors.initials: R
authors.lastname: Di
authors.affiliation: Department of Food Science, Rutgers, the State University of New Jersey, 60 Dudley Road, New Brunswick, NJ 08901, USA.
authors.forename: Malathi S
authors.initials: MS
authors.lastname: Vakkalanka
authors.affiliation: Department of Food and Nutritional Sciences, The University of Reading, PO Box 226, Whiteknights, Reading RG6 6AP, UK.
authors.forename: Chatchaya
authors.initials: C
authors.lastname: Onumpai
authors.affiliation: Eastern Regional Research Center, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA.
authors.forename: Hoa K
authors.initials: HK
authors.lastname: Chau
authors.affiliation: Eastern Regional Research Center, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA.
authors.forename: Andre
authors.initials: A
authors.lastname: White
authors.affiliation: Department of Food and Nutritional Sciences, The University of Reading, PO Box 226, Whiteknights, Reading RG6 6AP, UK.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Rastall
authors.affiliation: Department of Food Science, Rutgers, the State University of New Jersey, 60 Dudley Road, New Brunswick, NJ 08901, USA.
authors.forename: Kit
authors.initials: K
authors.lastname: Yam
authors.affiliation: Eastern Regional Research Center, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA.
authors.forename: Arland T
authors.initials: AT
authors.lastname: Hotchkiss
mesh_terms: D001422:Bacterial Adhesion; D004927:Escherichia coli Infections / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005243:Feces / Q000382:microbiology; D019073:HT29 Cells; D006801:Humans; D009844:Oligosaccharides / Q000737:chemistry* / Q000378:metabolism; D010368:Pectins / Q000737:chemistry / Q000378:metabolism*; D056692:Prebiotics / Q000032:analysis*; D022621:Shiga Toxin / Q000378:metabolism / Q000633:toxicity*
chemical_list: D029968:Escherichia coli Proteins; D009844:Oligosaccharides; D056692:Prebiotics; D022621:Shiga Toxin; D010368:Pectins
keywords: Anti-adhesion; HT29 cells; Orange pectic oligosaccharides; STEC; Shiga toxin 2; TaqMan RT-qPCR; rRNA depurination