Studying bacterial cell division using optical tweezers

It is hypothesized that division of bacteria is driven by a contractile ring of FtsZ proteins (FtsZ is a tubulin homologue). Optical tweezers are capable of measuring and exerting forces on micron-sized beads up to (a few) 100 pN with high accuracy. Here we explore the possibility of attaching beads as handles to a living bacterium to study the dynamics and mechanics of force generation during cell division. We show that it is possible, using dsDNA as a spacer, to specifically attach such beads to living E.coli cells expressing an epitope-tagged protein on the cell surface. Furthermore, we show that such a bead can be attached to a living cell that is held by beads attached to its poles. Also, we demonstrate that cells can grow and divide while being held by trapped beads. Finally, results are presented on the creation of novel protein