Figure 5. Ultrastructural analysis of active zones in ten-a mutants.
Representative transmission electron microscopy (TEM) images of active zones in control (A) and ten-a null mutant antennal lobes (B). T-bar profiles are visible in both genotypes, though reduced in number in the ten-a mutant. Scale bar = 500 nm. (C) High magnification TEM of a single active zone in a control animal. Note the normal T-bar morphology. (D–H) High magnification TEM images of active zones in ten-a mutants. In some cases, normal (D) morphology is observed. In the majority of cases, defects including multiple T-bars (E), misshapen T-bars (F), detached T-bars (G), and continuous electron dense material (H) are evident. Scale bar = 100 nm. (I) Quantification of T-bars per unit perimeter of measured antennal lobe terminals. All terminals were measured, including ORNs, PNs, and LNs. ten-a mutants display a 27% reduction from control animals. Data represent mean ± SEM. (J) Distribution of T-bar defects as a percentage of the total T-bars. Here, n = 1103 T-bar per unit perimeter measurements from three animals for control and n = 847 T-bar per unit perimeter measurements from three animals for ten-a.