Reduced clarity of OSN axon bundles and glomeruli in BACE1-/- OBs. Whole-mount preparations of OMP-GFP; BACE1+/+ (A, B, C) and OMP-GFP; BACE1-/- (D, E, F) OBs from 30 day-old mice were imaged for GFP fluorescence by laser scanning confocal microscopy. Z-stacks of optical sections were collected and collapsed into single images (A, B, D, E). Higher magnification images (B, E) of boxed regions in (A, D) show decreased clarity of OSN axons and reduced definition of glomeruli in the BACE1-/- OB as compared to BACE1+/+. Abnormal morphologies of BACE1-/- relative to BACE1+/+ glomeruli are particularly evident in individual optical sections taken at a depth of ~110 μm from the dorsal surfaces of OBs (C, F). Note that the BACE1-/- OB appears smaller in overall size relative to BACE1+/+ (compare D to A). Images were taken of the dorsal OB surfaces and are shown with the anterior tips of the OBs at the top.