Real-time observation of Escherichia coli cells under irradiation with a 2-MeV H+ microbeam

A high-energy H+ microbeam generated by tapered glass capillary optics was applied to a single Escherichia coli cell, in order to evaluate the effects of irradiation on the activity of the flagellar motor and cell growth in real time. The flagellar motor of the tethered cells was stopped by irradiation with an average ion fluence of 2.0 × 1012 protons/cm2. When a lower dose was applied to the cells attached to the substrate, an elongated cell, which seemed ready to divide, divided into two daughter cells; however, the daughter cells did not elongate, neither did further cell division occur.