Tannic acid mordanting of a meiotic spindle: no evidence for a microfilament system.

Tannic acid as a mordant in electron microscopy has recently been successfully employed in demonstrating a prominent spindle microfilament system in an alga [21]. The same technique was applied in this study to meiotic spindles of the crane fly Pales ferruginea. Although the contrast of the intertubular spindle matrix is very much improved with this technique, no filamentous structures suggesting the existence of a microfilament system in prometa-, meta-, and anaphase spindles could be detected. This may possibly indicate that spindles of different eukaryotes exhibit profound differences in their basic composition.