Ref ID : 7559
Igor B. Raikov and V.G. Kovaleva; Fine Structure of the Circumoral Ciliature and Pharyngeal Apparatus of the Marine Ciliate Helicoprorodon gigas (Gymnostomata). Protistologica XVI(1):177-198, 1980
Reprint
In File
Notes
The apical cytostome of Helicoprorodon gigas is surrounded by 36-40 pairs of kinetosomes (one ciliated and one barren), which belong to 5 somatic kineties whose anterior ends spiral around the cytostome. In each of these kineties, the anterior 7-8 kinetosomes are paired, the other ones are solitary. The cytostome of non-feeding animals is filled with cytoplasm which is limited by the cell membrane and contains mucocysts. The pharyngeal apparatus is a true tubular basket, 50-60 µm long, which consists of 36-40 single nemadesmata and contains two concentric systems of pharyngeal lamellae of microtubules. Each nemadesma begins from the base of the barren kinetosome of a peribuccal pair. The pharyngeal lamellae of the outer system are short (less than 10 µm); they start from the cell membrane around the cytostome and are not connected with kinetosomes. The microtubular lamellae of the inner system are long (40-50 µm) and line the entire interior of the pharyngeal basket; they seem to start, as transverse fibres, from both kinetosomes of the peribuccal pairs. Each system contains about 145 lamellae. Two microfibrillar sheaths exist in the apical part of the cytopharynx, a shorter outer one, which encircles the outer system of pharyngeal lamellae and is connected with the microfibrillar layer at the ectoplasm-endoplasm limit, and a longer inner one, which separates the two systems of pharyngeal lamellae. The interior of the cytopharynx is filled with cytoplasm containing many vesicles, dense bodies, and mitochondria. Bundles of about 40 µm long toxicysts are implanted outside the cytopharynx into a spiral ridge which makes about two turns around the cytostome. There are two types of peribuccal toxicysts, ones containing a few (less than 10) longitudinal microtubules inside the capsule, and ones containing many (40-50) intracapsular microtubules in their middle and basal parts.