Fig. 2.

Cross sections through Bacillus subtilis spores embedded using different protocols. Apart from the contrast, no significant differences between the spores are visible. A. Epon embedding (without block contrasting and osmium tetroxide post-fixation). On-section staining with uranyl acetate and lead citrate. B. LR White rapid embedding using 2.5 μl accelerator per ml monomer resin (LRW 2.5 μl). On-section staining as in A. C. LR White rapid embedding as in B but on-section staining with uranyl acetate/methyl cellulose. D. LR White rapid embedding using 5 μl accelerator per ml monomer resin (LRW 5 μl) and on-section staining as in C. (ct) outer and inner spore coats; (co) cortex; (sc) spore core; (m) core membrane. Bars = 100 nm.