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Three suctorian ciliate species, Paracineta livadiana (Mereschkowsky, 1881), Loricophrya bosporica Sergeeva & Dovgal, 2014 and Acinetopsis lynni Baldrighi et al., 2020 are found as epibionts on meiobenthic nematodes in an oxygen minimum zone of the Arabian Sea. All three species are recorded here for the first time from the Indian Ocean.

Epibiosis is common among ciliates and crustaceans because the calcified surface of the crustacean body offers a suitable site for colonization by the epibiont. Suctoria are among the most common epibiont ciliate groups of freshwater decapod crustaceans. The aim of this study is to increase knowledge of suctorians as epibionts of freshwater decapod crustaceans of the families Cambaridae and Pseudothelphusidae. Crustaceans were collected from three rivers and one pond in Chiapas, Mexico. Six species of suctorian epibionts were recorded: Acineta tuberosa, Podophrya maupasi, P. sandi, Tokophrya cyclopum, T. quadripartita and Trichophrya epistylidis. This is the first record of ciliate epibionts on members of family Pseudothelphusidae (represented by Phrygiopilus montebelloensis and Raddaus bocourti), and the first record of suctorians epibionts on Procambarus (Austrocambarus) sp. (Cambaridae).

The luminescent photoprotein aequorin was used to measure intracellular free Ca 2+ in three species of suctorian protozoon, Trichophrya riederi, Trichophrya collini and Trichophrya rotunda . Resting [Ca 2+ ]i ranged from about 75–110 nM, and was unaffected by a change in temperature of the perfusate. Spontaneous Ca 2+ transients were observed in all three species, with peak amplitudes ranging from 100–600 nM. In T. riederi and T. rotunda , three categories of transient (small, intermediate, large) were recorded; T. collini displayed only small transients. In both T. riederi and T. collini , raising the temperature from 5° to 26°C led to an increase in the frequency of transients. Furthermore, in T. riederi , large transients occurred only at the higher temperature. The frequency of spontaneous contractions of the tentacles of T. riederi was also temperature-dependent. Increasing the temperature over the range 5–26°C led to a concomitant increase in contraction frequency and a decrease in mean tentacle length. The possible mechanisms of spontaneous Ca 2+ transient generation and their role in the control of contraction are discussed.

Copidognathus nautilei Bartsch, 1997, from a hydrothermal vent field of the Mid-Atlantic Ridge at about 13 degrees N, 45 degrees W and 4090 m depth, was infested with the suctorian Corynophrya abyssalis n. sp., with up to 58 epizoans per mite. The new suctorian has a sacciform body with seven longitudinal ribs, a compact macronucleus and up to 40 non-retractile tentacles. The budding is exogenous. The systematic position of the new species and the genus Corynophrya is discussed, as well as infestation rates and sites of suctorians on their halacarid hosts.

The morphology, infraciliature, and life cycle of Endosphaera terebrans, a suctorian endocommensal of peritrichs, have been studied with the aid of silver impregnation. The life cycle of Endosphaera terebrans begins with infection of the host cell by a small larva. The swarmer has a pointed needle-like cellular projection and two rings of cilia. The swarmer penetrates the peritrich, loses the cilia, and then matures into an adult. The infraciliature of the adult form has four rows of barren kinetosomes that lack kinetodesmal fibers. By endogenous budding, a migratory larva is produced that leaves the host cell through the peristomial disc and that can infect other peritrichs.

An improved method for the preparation of Triton X-100 extracted models of Didinium nasutum was established. Didinium models prepared by treatment with a Triton X-100 solution, containing specific proteolysis inhibitors and dimethyl sulfoxide, maintained an intact shape at 25 degrees C for a longer time than models prepared by treatment with a Triton X-100 solution not containing the proteolysis inhibitors and dimethyl sulfoxide. The improved Didinium models were reactivated so as to swim forward in the presence of Mg2+ and ATP or ADP. They did not swim backward in response to Ca2+, in contrast to well-known Paramecium models. However, the improved Didinium models showed circular swimming and spinning in response to 10(-6) M or higher concentrations of Ca2+. This observation suggests that the quick directional change as well as the spinning, which are characteristic of live Didinium, are due to an increase in the endoplasmic Ca2+ concentration around the ciliary system. The response of the Didinium ciliary system to Ca2+ may differ from the response of the Paramecium ciliary system to Ca2+.

A total of 4.1% infestation with Chilodonella spp. was found among fish studied in 144 tanks in 1987-1989, representing 14.0% of the tanks in which fish are reared at four salmonid farms in northern Finland. Two species were found, C. hexasticha and C. piscicola, and both occurred on salmon (Salmo salar L.), sea trout [S. trutta m. trutta (L.)] and brown trout [S. t. m. lacustris (L.)]. Variability was observed in the length and width of the C. piscicola specimens and the number of ciliary rows or kineties. Large specimens which had more kineties than average for C. piscicola were found mainly on the skin of salmon aged 1-2 years. The number of kineties in the right ciliary band was found in stepwise logistic regression analysis to be of importance when typing C. piscicola specimens. Fingerlings were found to be more susceptible to Chilodonella infestation than older fish, and mortality varied in the range 2-10% in the course of the epizootics in the three fish species. Most mortality cases were caused by C. hexasticha, occurring mainly on the gills of the fish. Chilodonella piscicola was most often found in salmon and occurred at lower water temperatures than C. hexasticha (mean water temperature when found for the first time being 13 degrees C and 16 degrees C, respectively).

Protozoal concentrations were determined in rumen and cecal contents of 20 blue duikers (Cephalophus monticola). Ten animals of each sex were fed either a high concentrate or high roughage diet. Rumen protozoa were present in 19 of the 20 animals and concentrations ranged from 4.5 to 33.7 × 106 per g of rumen contents. At the higher concentrations, protozoal cells equaled between 30–40% of the total rumen contents volume. No protozoa were found in cecal contents. Weight of rumen contents was higher in females than in males (P < 0.01), and rumen protozoa concentrations were higher in males (P < 0.05) and in those animals fed the high concentrate diet (P < 0.05). All the protozoa were identified as belonging to a single species, Entodinium dubardi. However, an average of about 30% of the E. dubardi cells varied from the typical morphology of this species. These cells appeared to be on variation lines leading toward 7–10 other non-caudate species of Entodinium. The present data were used to evaluate and discuss the concept of variation lines within E. dubardi.

Ejectable trichocysts were isolated from the ciliate Pseudomicrothorax dubius. Polyclonal antibodies were raised against three groups of trichocyst proteins: G1 (30-31 kDa), G2 (26-27 kDa) and G3 (15-20 kDa). By indirect immunofluorescence, the three antisera strongly label the shafts of ejected trichocysts and the proximal ends of condensed trichocysts within the cells. By immunogold labeling for electron microscopy, the three sera specifically recognize the shafts of both extended and condensed trichocysts and shaft precursors in pretrichocysts as well. On one-dimensional immunoblots of isolated trichocysts, anti-G1 serum recognizes the G1 proteins, anti-G2 serum detects G2 proteins and some G1 proteins, and anti-G3 serum reacts with 15 bands, mainly the G3 and (30-41)-kDa proteins. In cells with and without trichocysts, the sera recognize non-ejectable trichocyst proteins at 41-42 kDa and 47 kDa. On two-dimensional immunoblots of isolated trichocysts, anti-G1 serum labels proteins with a pI of 4.75-5.7, anti-G2 serum labels proteins with a pI of 4.75-6.25 and anti-G3 serum labels proteins with a pI of 4.7-6.6. Analyses of cells with and without trichocysts allow identification of possible precursors between 41 and 47 kDa. Some are in the same pI range as their putative products, but others, labeled by anti-G3 serum, are less acidic than most of their mature products.

Summary The general architecture and cortical surface structures have been studied in the giant freshwater ciliate Bursaria truncatella at various stages of its cell cycle: (1) prior to division, (2) during division, (3) after division in the course of differentiation of the new oral apparatus, (4) after completion of differentiation and growth. Changes in the structure of both the somatic and oral ciliatures have been traced. The somatic cilia become sparse during the preparation to division, while before the onset of cytokinesis new cilia arise and grow in the daughter cells after the division. The adorai membranelles and the old perisomal cavity dedifferentiate before the onset of cytokinesis, while new ciliary zones of the peristome and the new peristomal cavities begin to form in early cytokinesis. In the opisthe, the primordium of the new oral apparatus arises later than in the proter. At initial stages of formation of the new oral apparatuses, the primordia of the peristomal cavities and those of the new peristomal ciliary zones are spatially separated in either of the daughter cells. The development of the ventral cut of the peristome margin, typical of B. truncatella , has been followed. In both daughter cells it results from fusion of two apertures, the subapical and the ventral ones. Stages of formation of the superficial cortical structures inside the peristome, leading to the appearance of cirromembranelles, have been demonstrated. Differences in the structural organization of the dorsal surface of the peristome exist between fed and unfed cells. Our SEM study of morphogenesis in B. truncatella lends support to the transfer of this ciliate from the class Polyhymenophorea to the lower ciliate class Kinetofragminophorea and to the creation of a special order Bursariida in it. Some of the structures observed may be used as morphological markers when studying the regulatory mechanisms of morphogenesis in ciliates.

In a previous paper (8) an organized structure was described in the macronuclei of certain old organisms of Tokophrya infusionum. It was found that the same honeycomb structure appears in great abundance in the macronuclei of overfed organisms. This permitted a better three-dimensional reconstruction of the described structure. Since the defined structure may be experimentally induced, it offers an opportunity for further more detailed studies as to its nature and meaning.

Elektronenmikroskopische Untersuchungen am sessilen Susswasser-ProtistenTokophrya infusionum zeigen besonders komplizierte Strukturen der «Tentakel» und der «Haftscheibe». Die Tentakel sind von zwei Membranen umgeben und umschliessen eine Anzahl von Langselementen. Ihre Spitzen sind aus einer grosseren Zahl von «Papillen» zusammengesetzt. Die Haftscheibe besteht aus einem reichen Fibrillennetz.

The life-cycle of Subulura suctoria, a caecal nematode of poultry in Egypt had been worked out for the first time. The prepatent period was 45 days. The morphological features of the different larval stages found in experimentally infected chicken as well as the adult worms are presented. The present situation of the genus Subulura and its proper place is also discussed.

By random examination of various insects for cysticercoides of tapeworms, larvae of round worms were encountered attached to the intestinal wall of beetles, Ocnera hispida and Blaps polycresta. The morphological features of the larvae were discussed and materials from infected beetles were fed to chicken and we obtained embryonated eggs from their droppings and on making post-mortum examination of chicken, adult Subulura suctoria worms were found.