Cytological abnormalities induced by inactivation of the δ PT1 gene: cellular level. (a): surface view of the dorsal side of a control cell, showing the basal body pattern, the outline of the oral apparatus (oa) and post-oral fibers (of) and the contractile vacuole pores and rootlets (cv). (b), (c), and (d): transformed cells from the pool presented in Table 1. (b), (c): sub-surface view of two transformed cells, showing disorders in the organization of the oral apparatus and postoral fibers, and the presence of erratic microtubule bundles (short arrows) and groups of intracytoplasmic basal bodies (arrows). (d): dorso-lateral view of a transformed cell showing erratic microtubule bundles (short arrows) and altered organization of oral apparatus and post-oral fibers. Note that the three transformed cells display a less constrained shape than the control. Bar for 10 μM : 0.5cm long.