Crash landing of Vibrio cholerae by MSHA pili-assisted braking and anchoring in a viscous environment

Mannose-sensitive hemagglutinin (MSHA) pili and flagellum are critical for the surface attachment of Vibrio cholerae. However, the cell landing mechanism remains largely unknown. Here, combining the cysteine-substitution-based labelling method with single-cell tracking techniques, we quantitatively characterized the landing of V. cholerae by directly observing both pili and flagellum of cells in viscous solutions. MSHA pili are evenly distributed along the cell length and can stick to surfaces at any point along the filament. With such properties, MSHA pili are observed to act as a brake and anchor during cell landing which include three phases: running, lingering, and attaching. Resistive-force-theory based models are proposed to describe near-surface motion. Importantly, the role of MSHA pili during cell landing is more apparent in viscous solutions. Our work provides a detailed picture of the landing dynamics of V. cholerae under viscous conditions, which can provide insights into ways to better control V. cholerae infections.