Detachment of axopodia from the heliozoan, Echinosphaerium nucleophilum

Agitation of live cells in 10% ethanol produced a loosening of cortical cytoplasm and mass release of axopodia from their anchorages. A balloon-like swelling quickly formed at the proximal end and, about 15 min after detachment, at points along the axopodium. The dense core shaft, presumably the axoneme, was still visible under phase contrast shortly after detachment, but it dissolved within 30 min. The detached axopodia did not change in appearance, however, when the medium included 0.6 mM MgSO4, 1 mM GTP, and 50–150 mM EGTA, pH 7, at either room temperature or 4 °C. This procedure can serve as a starting point for combined biochemical-ultrastructural investigation of these axopodia and the unique characteristics of their microtubules.