We have developed a broadly applicable method for labeling and imaging pili in live cells. This technique uses a combination of simple genetics and standard epifluorescence microscopy in which a cysteine substitution is made in the major pilin subunit for subsequent labeling with thiol-reactive maleimide dyes. Maleimide-conjugated large molecules can also be used to physically impede the dynamic activity of nanomachines. Visualization of extracellular nanomachines using this approach can dramatically improve our understanding of the role these structures play in distinct bacterial behaviors.
An article describing these methods in detail was published in Nature Protocols.
The methods are also described in the following publications: