A dry-fracture technique for the optimum preparation of microsporidia-infected tissues for scanning electron microscopy

A technique for the optimum preparation of microsporidia for scanning electron microscopy is described. Microsporidian-infected tissues were subjected to a triple fixation procedure followed by slow dehydration and critical point drying. Fracturing of the tissue to reveal details of both host and parasite was delayed until immediately before coating of specimens with gold; the exposed parasites were therefore free of extraneous contamination, displayed minimum distortion and retained their spatial relationships with each other and with the host tissue. The value of the technique is illustrated by examination of microsporidia both with and without sporophorous vesicles, including species representing the genera Tuzetia, Amblyospora, Pleistophora and Nosema.