Characterization of the response of Escherichia coli to l-fucose in bacterial swimming motility

L-Fucose, as a monosaccharide in nature, plays a crucial role in bacteria colonization. Escherichia coli (E. coli), as a common microorganism in environment, utilize bacterial flagellar motor to drive the rotation of flagella, which is regulated by chemotactic signal transduction signals. Yet the effect of L-fucose to bacterial motility remains unclear. The effect of L-fucose on the swimming motility of bacteria was investigated from the level of single flagellar motor to individual cell and cell population by employing a bead assay, a high-throughput 2D tracking assay and a high-throughput dark-field flicker microscopy. The results showed that the swimming motility of the bacteria cultured with L-fucose was decreased, while the tumble frequency increased. Furthermore, the behavioral alterations of bacteria affected by L-fucose were directly reveled by measuring the cell distribution of bacteria swimming near surfaces and bacterial surface adhesion, suggesting that L-fucose promotes bacterial surface aggregation and surface adhesion. The effect of l-fucose on bacterial swimming motility characterized in this study are consistent with the key role that L-fucose plays in bacterial colonization.