The fixation and infiltration of larger brown algae (Phaeophyta) for electron microscopy

Abstract

The larger brown marine algae are extremely difficult to prepare for electron microscopy. Most previous papers have illustrated artifacts such as negative contrast membranes, myelin figures of disturbed membrane systems, vesiculation of the cytoplasm and effects resembling plasmolysis. Although no single fixation and infiltration technique produces excellent results with all species tested, the use of glutaraldehyde/formaldehyde primary fixatives with caffeine in the fixative and buffer washes, followed by osmium post-fixation, dehydration in ethanol or acetone and slow infiltration provides a fixation image free from the most common aberrations.