Single cell fluorescence imaging of glycan uptake by intestinal bacteria.

Hehemann, Jan-Hendrik; Reintjes, Greta; Klassen, Leeann; Smith, Adam D.; Ndeh, Didier; Arnosti, Carol; Amann, Rudolf; Abbott, D. Wade

Microbes in the intestines of mammals degrade dietary glycans for energy and growth. The pathways required for polysaccharide utilization are functionally diverse; moreover, they are unequally dispersed between bacterial genomes. Hence, assigning metabolic phenotypes to genotypes remains a challenge in microbiome research. Here we demonstrate that glycan uptake in gut bacteria can be visualized with fluorescent glycan conjugates (FGCs) using epifluorescence microscopy. Yeast α-mannan and rhamnogalacturonan-II, two structurally distinct glycans from the cell walls of yeast and plants, respectively, were fluorescently labeled and fed to Bacteroides thetaiotaomicron VPI-5482. Wild-type cells rapidly consumed the FGCs and became fluorescent; whereas, strains that had deleted pathways for glycan degradation and transport were non-fluorescent. Uptake of FGCs, therefore, is direct evidence of genetic function and provides a direct method to assess specific glycan metabolism in intestinal bacteria at the single cell level.

ISME Journal: Multidisciplinary Journal of Microbial Ecology, 2019, Vol 13, Issue 7, p1883

1751-7362

Academic Journal

10.1038/s41396-019-0406-z