Ref ID : 7742
Bernard Pelvat; [Observations sur L'ultrastructure de L'appareil Buccal chez le Cilie Heterotriche Stentor coeruleus]. Protistologica XXI(1):61-80, 1985
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Ultrastructural observations on the buccal apparatus of Stentor coeruleus allows us to demonstrate some structures and fibers systems which have not been described until now in this species. Frontal field: Pairs of kinetosomes carry the classical fiber systems we can observe in the cortical kineties, but in addition nematodesmata are associated with the pairs of kinetosomes. The presence of these latter fibers shows that the frontal field of Stentor must be considered a true oral structure, in spite of its cortical origin. Membranelles: Transverse ribbons formed by 1 or 2 microtubules are associated with each kinetosome of the rows forming the membranelle, a characteristic of the S. coeruleus membranelles. We have described here a major, dense fibrillar system, associated with the proximal part of the kinetosomes in the membranelle. Microtubular fibers, not directly connected to the kinetosomes, may be observed between the membranelles. Paroral: Positioning of the kinetosomes and associated fibers depends on the position of the paroral in the buccal apparatus. We have attempted to understand the organisation of the microtubular roots of the membranelle. Each microtubular root makes a twist along its vertical axis as it descends into the cell but remains oriented vertically, except in the infundibular region. The microtubular ribbons slip with respect to one another and come to lie in direct contact with the inside edge of the neighbouring root, forming a continuous fiber sheet.