Fig. 2. Progressive aspiration of a swollen Xenopus oocyte nucleus. The Xenopus oocyte nucleus was labeled with the membrane dye FM 4-64 and progressively aspirated into a micropipette. Each image (1-9) was taken after rapid equilibration with a set imposed pressure. Note the membrane wrinkles near the pipette entrance (white arrow) consistent with shear resistance of a solid-like network. The distance between the bracketed fluorescence spots increases, thus showing local envelope stretching of nearly 300%. Scale bar: 250 µm.