Oriented imaging of 3D subcellular structures in bacterial cells using optical tweezers

Using oscillating optical tweezers, we show that controlled alignment of rod-shaped bacterial cells allows imaging fluorescently labeled three-dimensional (3D) subcellular structures from different, optimized viewpoints. To illustrate our method, we analyze the Z ring of E. coli. We obtain that the radial width of the Z ring in unconstricted cells is about 120 nm. This result suggests that the Z ring consists of an extremely sparse network of FtsZ filaments.