For electron tomography (ET), semi-thick sections were collected on carbon coated 200 mesh copper grids (Ted Pella, Inc.), dried, and stained and washed similarly, except that the microwave irradiation steps were extended to 2 minutes each. Tomography grids were then immersed briefly in goat anti-mouse IgG 10 nm gold conjugate (Ted Pella, Inc.) to add fiducial markers on both sides of the sections and then thoroughly washed with water.