Tokuyasu Method: From Basics to Applications

Abstract

Ultracryotomy is a standard immunoelectron microscopy technique in the cell biology field. It is similar in principle to the frozen section technique, which is often used for histochemistry in light microscopy. The reason why the immnoelectron microscopy using ultrathin cryosections is referred to as the Tokuyasu method is that most of the critical steps, from fixation to collecting and observing sections, were developed by Dr. Kiyoteru Tokuyasu about half a century ago, and that his original protocols are basically still in use even today. In this review, the major steps of the current standard protocol of the Tokuyasu method are explained based on the author’s experience. In addition, various applications of the method, especially the combination of the Tokuyasu method with other methods, taking advantage of the non-emmbedded specimen are introduced.