Pravina Yadav | ALES Graduate Seminar

Date(s) - 27/04/2022
9:00 am - 10:00 am

A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Pravina Yadav. This seminar is open to the general public to attend.
Meeting ID: 950 1412 5559 | Passcode: 718801

Thesis Topic: Mapping glycan binding profiles of the gut microbes using novel liquid glycan array

MSc with professor Ben Willing.

Seminar Abstract:

The role of glycan binding of gut microbes has been shown in colonization and interactions between microbiota and host. While glycan binding of selected pathogens has been explored in a targeted way, there has been limited research on glycan binding patterns of gut commensals. This has partially been limited by the tools available to assess glycan binding. In this thesis, a novel Liquid glycan array (LiGA), which comprises a library of glycosylated M13 phage particles with silent DNA barcodes in the phage genome, was used to test glycan binding profiles of gut bacteria. The potential role of glycan binding in host specificity of Limosilactobacillus reuteri was explored by comparing 16 L. reuteri strains consisting of 4 isolates from each of murine, porcine, poultry and human lineages.  Many of the enriched glycans were shared amongst L. reuteri isolates, however, there was no evidence that isolates from the same host shared greater glycan binding similarity, thus glycan binding profile did not appear to be a key determinant of host specificity. However, some strains showed notable unique glycan enrichment. In particular a poultry isolate L. reuteri JCM 1081 showed drastically higher enrichment of Fucα1-2Galβ-Sp (Fold change (FC) = 88, FDR < 0.0001) and Galβ1-4Glcβ-P4 (FC = 46, FDR < 0.0001). The unique binding profile of this isolate conforms with the observations of enhanced adhesive capacity to gut epithelial cells.

Next, to understand the profiles of glycan binding of other bacterial species, we tested glycan binding of taxonomically diverse bacteria from three different phyla Firmicutes/Bacillota, Bacteroidetes/Bacteroidota, Proteobacteria/Pseudomonadota consisting of 9 different species L. reuteri, Escherichia coli, Bacteroides dorei, Bacteroides thetaiotamicron, Bacteroides fragilis, Bacteroides vulgatus, Limosilactobacillus mucosae, Citrobacter fruendii, and Clostridium ramosum. Results indicate that the taxonomic closeness leads to similar glycan binding of gut bacteria with few exceptions.

We established that LiGA is an effective new tool for characterizing glycan binding of bacteria. Exploring glycan binding profiles of more commensal bacteria using this novel approach will provide new insights into intestinal microbial ecology and provide strategies to manipulate the microbial community through the provision of glycans.