@article{bradbury_song_zhang_1997, title={Stomatogenesis during the formation of the tomite of Hyalophysa chattoni (Hymenostomatida : Ciliophora)}, volume={33}, ISSN={["0932-4739"]}, DOI={10.1016/S0932-4739(97)80052-1}, abstractNote={Summary The functioning oral apparatus of the feeding stage of Hyalophysa chattoni Bradbury, 1966 , arises from pre-existing structures in the tomite that change their form and position during a metamorphosis to the trophont. These structures are the relic of a microstome oral apparatus in the non-feeding tomite. Their origin has been studied during tomitogenesis using Shi's protargol method. In general, this method of silver impregnation confirms the earlier description of tomitogenesis by Chatton and Lwoff, but it reveals significant details concerning the fate of certain transient kineties that form structures which later contribute to the functioning cytostome. Before palintomy, all the kineties of the encysted tomont straighten and become meridional. Nine somatic kineties − x , y , and z (the “oral” kineties), and kinety a , thirteen kineties altogether extend approximately from pole to pole. Kinety a parallels K1. After the first division of the tomont, the kinetosomes of K a multiply in a broad band to the left of the kinety. During subsequent divisions, the kinetosomes in the band assemble into three meridional, transient kineties — K a , K b , and K c . After the last division, each daughter has nine meridional somatic kineties spaced around the body and six meridional ventral kineties crowded between K1 and K9. During tomitogenesis, all the ventral kineties shorten; only the posterior halves of x , y , and z are retained. Kinety x extends a little farther anteriad than y and z . This extension separates from the rest of x and sinks into the cytoplasm where it forms the tuft of cilia on the proximal wall of the developing rosette. The shortened a , b , and c migrate left, anterior to x , y , and z . Both extremities of K a disappear, and the remaining kinetosomes proliferate to form the ogival field, a mid-ventral patch of closely set cilia found only in the tomite. Kinety b disappears leaving behind a barren haplokinety near the apex of the tomite. Kinety c disappears completely, but under the pellicle in the place where it disappears, a microtubule-lined canal, the cytopharynx of the microstome, parallels the ogival field and the haplokinety to the apex of the organism. The last step in microstome formation is the doubling of the anterior portion of kinety 8 and the quadrupling of the anterior fragment of kinety 9 to produce falciform fields 8 and 9 (FF8, FF9), the equivalent of oral polykineties 2 and 1 in other hymenostomes. The oral apparatus of the microstome consists of an anterior haplokinety (paroral), three polykineties (FF9, FF8, and the ogival field), and the cytopharynx. Except for the falciform fields, all these structures originate from kinety a . The falciform fields originate as proliferations of the ends of somatic kineties 8 and 9, indicating that, at least in part, apostomes have telokinetal stomatogenesis. The origin of K a is revealed during the formation of the macrostome. After the tomite encysts on the host, the ogival field disappears completely within hours. When metamorphosis to the trophont begins, the barren haplokinety and the lateral canal migrate posteriad over the ventral surface and then dorsad, establishing the limits of the extended cytostome, a greatly enlarged surface on the trophont. The haplokinety then disappears, and the microtubules of the cytopharynx remain as ribs under the extended cytostome. Falciform field 8 remains unchanged, still a dikinety. The kinetosomal rows of FF9 become disorganized, and paired kinetosomes move over the anterior ventral surface to form the anterior field of scattered kinetosomes characteristic of Hyalophysa . The posterior portion of FF9, losing kinetosomes as it goes, moves across the mid-ventral surface and stops at the left of K1 where K1 makes a sharp angle to parallel the extended cytostome. There the last remnant of FF9 remains as K a in the trophont. It does not function as oral ciliature. It is an anlage for part of new microstomes in daughter cells that will be formed days hence. The microstomes of these daughter cells will be completed at that time by the proliferation of kineties 8 and 9 to form FF8 and FF9. Thus, in Hyalophysa the tomite's microstome is formed in part by a derivative of K9 (K a ) from the preceding generation and completed by proliferation of K8 and K9 from the present generation. Stomatogenesis is telokinetal, but modified by a somatic derivative from one generation carried over to the next.}, number={4}, journal={EUROPEAN JOURNAL OF PROTISTOLOGY}, author={Bradbury, PC and Song, WB and Zhang, LM}, year={1997}, month={Dec}, pages={409–419} }