Fig. 3

Longitudinal sections through Paramecium basal bodies after glutaraldehyde/osmium classical fixation (a, b) or with an additional tannic acid treatment performed after cell permeabilization (c, d). Bars 200 nm. a Connection between the Tz and the cell surface. Inside the basal body, the Tz is organized in three plates: the terminal plate (blue line), the intermediate plate (white) and the axosomal plate (red line). Outside the basal body, the terminal plate extends to link the epiplasm (arrow). Inside the basal body, dense granules are observed. Al alveolar sac , a vacuolar system located beneath the outer cell membrane found in all representatives of the Chromalveolata. b Comparison of Tz of non-ciliated and ciliated basal bodies: Tz of ciliated basal bodies is more extended than that of non-ciliated basal bodies, but the three plates and the connection with the epiplasm are detected in both of them. c, d (modified from [12]): short (c) and long (d) basal bodies. The cartwheel is longer in the long basal body. The three plates, as well as the connection with the epiplasm (arrowheads) can be observed on the short non-ciliated basal body; connections between the striated rootlet and the epiplasm appear as delicate links (arrow). A schematic representation of anchored ciliated and non-ciliated basal bodies has been inserted in this figure showing the transition zone with its three plates: the terminal plate (blue), the intermediate plate (discontinuous line) and axosomal plate (red)