# Discrete long-range on-cell motion of bacteriophage T4

## TL;DR

This study shows that bacteriophage T4 moves in a long-range walking motion on the surface of bacteria before infecting them.

## Contribution

The study provides the first direct evidence of discrete long-range on-cell motion of bacteriophage T4 using single-particle fluorescence microscopy.

## Key findings

- Bacteriophage T4 exhibits long-range motion on or near the surface of Escherichia coli B.
- The motion involves repeated shifts in the tethering location of the phage.
- Single-particle fluorescence microscopy reveals dynamic interactions before irreversible binding.

## Abstract

The ability of a bacteriophage to distinguish between a suitable and a non-suitable bacterial host is critical for its survival. The series of events occurring between first contact and irreversible binding of a phage to its host is likely playing an essential role in the phage reproduction cycle. However, crucial information about the dynamic interaction between phages and bacterial cell surfaces is still lacking. Until now, most studies have focused on bulk measurements or on analyzing static interactions between phage and host using electron microscopy. These studies generally lack the ability to reveal the spatiotemporal dynamics that are key to understanding the “decision-making” process before the phage commits to infection. Here, we investigated nanoscopic on-cell dynamics using single-particle fluorescence microscopy, which allowed us to track the interaction between fluorescently labeled phage T4 and its host Escherichia coli B with high spatial and temporal resolution. We provide the first direct evidence that phage T4 exhibits long-range motion on or near the cell surface, facilitated by repeated shifts in mean positions of its tethering location.

We study the interaction of the virus bacteriophage T4 with bacteria. By tagging fluorescent dyes to bacteriophage T4, we can follow the movement of individual viruses when they approach the bacteria, which revealed that these bacteriophages perform a long-range walking motion on the surface of the bacteria.