Cytological abnormalities induced by inactivation of the δ PT1 gene: ultrastructural level. (a) Longitudinal section through a basal body (bb) and its cilium (ci) anchored in the surface between subpellicular alveoli (al). (b),(b'),(c),(c') and (d), (d') compare cross-sections at levels 1, 2 and 3, illustrated in (a), from control (b,c,d) and inactivated cells (b', c', d'). All sections are similarly oriented with respect to basal body and cell polarities and shown as seen from the cell center. Ciliary rootlets (cr) run upwards and to the left of the observer; newly formed basal bodies position anterior to the parent. (b), (b'): near the terminal plate (level 1), the C-tubules, visible in b are absent in b'. (c), (c'): level 2 section through mother and daughter basal bodies; in c', the mother organelle (posterior) shows a ring of 8 doublets and 1 triplet; the daughter basal body shows a more defective structure with one, possibly two singlets; the basis of the ciliary rootlet appears narrower and less dense in c'. (d), (d'): cross-section through level 3, showing the cartwheel; in (d'),both basal bodies show doublets and triplets (small arrows). (e): level 2 section through a field ("anarchic field" destined to generate a new oral apparatus at their next division) of basal bodies near the oral apparatus of a transformed cell showing rings of 9 doublets: note the incomplete rings (arrows), with empty triplet sites, as in (b') and (c'). Bars: 0.2 μM; same magnification in (b), (b'), (c), (c'), (d) and (d').