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Synthetic glycans for toxin and pathogen detection

Yosief, Hailemichael
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367936841

Abstract Details

2013, PhD, University of Cincinnati, Arts and Sciences: Chemistry.
Carbohydrates (glycans) are ubiquitous in nature and are commonly found covering the cell surface in the form of glycoproteins and glycolipids. Due to their role as receptors for toxins and pathogens, there is great interest in using synthetic carbohydrates to understand the binding of toxins and pathogens to the cell surface to develop glycan based diagnostics and therapeutics. We studied the binding of Shiga toxins (Stx1 and Stx2 subtypes) and uropathogenic E.coli strains to biotinylated disaccharide and trisaccharide analogues of globotriaosylceramide (Gb3, Gala1-4Galβ1-4Glc-ceramide), a receptor for Shiga toxins. Our binding studies using ELISA showed that Shiga toxin subtypes prefer binding trisaccharides to disaccharides. Specifically, Stx1 bound to Pk-trisaccharide (Gala1-4Galβ1-4Glc) and Stx2 subtypes (Stx2a and Stx2c) bound to the N-acetyl Pk-trisaccharide. Binding studies with the mixtures of the biotinylated oligosaccharides indicated that Stx1 and Stx2 subtypes (Stx2a and c) need to engage at least three trisaccharides for effective binding. Stx2d subtype, which is as potent as Stx2a, did not bind to N-acetyl Pk-trisaccharide but its B-subunit bound to N-acetyl Pk-trisaccharide like the B-subunit of Stx2a suggesting that the A-subunit of Stx2d interferes with binding. Similarly, the biotinylated oligosaccharides were tested for their ability to capture and differentiate uropathogenic E. coli strains from other types of E. coli using streptavidin coated magnetic beads. Pap pilus producing uropathogenic E.coli strains (J96, J96-pilE and CFT073) were captured by the oligosaccharides containing Gala1-4Gal residues. However the oligosaccharides with N-acetyl group did not capture the E. coli strains significantly. This work indicates that synthetic glycans could be used to detect and differentiate Shiga toxin subtypes as well as E.coli strains. These oligosaccharides could be further developed into point of care diagnostics as glycans are highly stable under variety of conditions.
David Smithrud, Ph.D. (Committee Chair)
Suri Iyer, Ph.D. (Committee Member)
James Mack, Ph.D. (Committee Member)
Alison Weiss, Ph.D. (Committee Member)
274 p.
Chemistry
Glycans; E, coli; Shiga toxins; ELISA; Magnetic beads; glycosylation;

Recommended Citations

Citations

  • Yosief, H. (2013). Synthetic glycans for toxin and pathogen detection [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367936841

    APA Style (7th edition)

  • Yosief, Hailemichael. Synthetic glycans for toxin and pathogen detection. 2013. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367936841.

    MLA Style (8th edition)

  • Yosief, Hailemichael. "Synthetic glycans for toxin and pathogen detection." Doctoral dissertation, University of Cincinnati, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367936841

    Chicago Manual of Style (17th edition)

ucin1367936841
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© 2013, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.