 Tubulin and microtubule-mediated processes, like cell locomotion, were seen by early microscopists, like Leeuwenhoek (1677).However, the fibrous nature of flagella and other structures were discovered two centuries later, with improved light microscopes, and confirmed in the 20th century with the electron microscope and biochemical studies.Microtubule in vitro assays for motor proteins such as dynein and kinesin are researched by fluorescently tagging a microtubule and fixing either the microtubule or motor proteins to a microscope slide then visualizing the slide with video-enhanced microscopy to record the travel of the microtubule motor proteins.