Volume 6 issue 10 October 2005
Intragranular vesiculotubular compartments are involved in piecemeal degranulation by activated human eosinophils
Rossana C. N. Melo, Sandra A. C. Perez, Lisa A. Spencer, Ann M. Dvorak and Peter F. Weller

Video 1: Tomography of an emptying eosinophil secretory granule exhibiting mobilized content and intragranular sub-compartments . Note that part of granule content within an internal membranous sub-compartment is relocated to the outer granule membrane. Eosinophils were isolated from healthy donors and stimulated with 100 ng/mL eotaxin for 1 h at 37 °C, chemically fixed and embedded in Eponate. Thick sections (400 nm) were cut and analyzed by automated EM tomography (dual-axis, tilting from -65 ° to + 65° at 1° intervals, magnification of 40,000x). The tomogram corresponds to Fig. 8.

Video 1 (.mov)

Video 2: Three-dimensional (3D) model of an eosinophil secretory granule showing intragranular membranous sub-compartments . The granule outer membrane was partially traced in red and intragranular vesiculotubular structures were outlined in blue. The intragranular membranous domains are organized as a flattened tubular network and tubules, with connections in some parts. Note an area of continuity between the intragranular membranous network and the limiting granule membrane. The 3D model was generated from ~ 4 nm thick serial slices obtained by automated electron tomography from an eotaxin-stimulated eosinophil. The 3D model corresponds to Fig. 8.

Video 2 (.mov)