Applications of fluorescence microscopy to single bacterial cells

Fluorescence-imaging techniques are now being applied to single bacterial cells for the determination of in vivo kinase and transcription activity, protein–protein interactions, protein localization and protein mobility. Time-lapse imaging is being used at a population level to study heterogeneities, colony morphologies and the genetic networks underlying these phenomena. We will discuss here the possibilities, advantages and limitations of such techniques, focusing on the use of green fluorescent protein and its spectral variants.