Morphology and morphometry of Bresslauides pratensis n. sp., a new soil ciliate (Ciliophora, Colpodea) from Turkey

A new colpodid ciliate, Bresslauides pratensis n. sp., was discovered in soil from a meadow field in Turkey. Its morphology was investigated using live observation, protargol impregnation, silver nitrate impregnation, and scanning electron microscopy. The new species differs from the congeners by the following combination of features: the cell size in vivo is about 135-180 μm × 130-160 μm; the body has an almost circular outline with a conspicuous bulge on the ventral side; the somatic cilia are arranged in about 105 densely spaced, sigmoidal kineties; a diagonal groove extends to the left cell side, terminating in a pronounced postoral sack; one almost globular macronucleus and usually two globular micronuclei; the oral structures occupy almost the anterior half of the cell and comprise a distally elongated right polykinetid and a crescentic left oral polykinetid, both restricted to the vestibulum; on average 12 vestibular, 31 postoral, and 55 left oral kineties. Based on the morphological data, it was concluded that B. pratensis is a well-outlined and distinctive member of the genus Bresslauides. Additionally, the most recent molecular data on the order Colpodida and genera Colpoda, Bresslaua, and Bresslauides are briefly discussed.     

Pseudocollinia brintoni gen. nov., sp. nov. (Apostomatida: Colliniidae), a parasitoid ciliate infecting the euphausiid Nyctiphanes simplex

A novel parasitoid ciliate, Pseudocollinia brintoni gen. nov., sp. nov. was discovered infecting the subtropical sac-spawning euphausiid Nyctiphanes simplex off both coasts of the Baja California peninsula, Mexico. We used microscopic, and genetic information to describe this species throughout most of its life cycle. Pseudocollinia is distinguished from other Colliniidae genera because it exclusively infects euphausiids, has a polymorphic life cycle, and has a small cone-shaped oral cavity whose left wall has a field of ciliated kinetosomes and whose opening is surrounded on the left and right by 2 'oral' kineties (or ciliary rows) that terminate at its anterior border. Two related species that infect different euphausiid species from higher latitudes in the northeastern Pacific Ocean, Collinia beringensis Capriulo and Small, 1986, briefly redescribed herein, and Collinia oregonensis Gómez-Gutiérrez, Peterson, and Morado, 2006, are transferred to the genus Pseudocollinia. P. brintoni has between 12 and 18 somatic kineties, and its oral cavity has only 2 oral kineties, while P. beringensis comb. nov. has more somatic kineties, including 3 oral kineties. P. oregonensis comb. nov. has an intermediate number of somatic kineties. P. beringensis comb. nov. also infects Thysanoessa raschi (a new host species). SSU rRNA and cox1 gene sequences demonstrated that Pseudocollinia ciliates are apostome ciliates and that P. brintoni is different from P. beringensis comb. nov. High densities of rod-shaped bacteria (1.7 μm length, 0.2 to 0.5 μm diameter) were associated with P. brintoni. After euphausiid rupture, high concentrations of P. brintoni and bacteria cluster to form 3 to 6 cm long filaments where tomites encyst and transform to the phoront stage; this is a novel place for encystation. P. brintoni may complete its life cycle when the euphausiids feed on these filaments.     

Morphology and infraciliature of two new marine ciliates, Paracyrtophoron tropicum nov. gen., nov. spec. and Aegyria rostellum nov. spec. (Ciliophora, Cyrtophorida), isolated from tropical waters in southern China

The morphology and infraciliature of two new marine cyrtophorid ciliates, Paracyrtophoron tropicum nov. gen., nov. spec. and Aegyria rostellum nov. spec., isolated from tropical waters in southern China, were investigated using live observation and protargol impregnation methods. Paracyrtophoron nov. gen. differs from the closely related Cyrtophoron by lack of fragment kinety at anterior ends of right somatic kineties and thigmotactic cilia in posterior portion of ventral surface, while from the well-defined Chlamydodon by lack of the cross-striped band around the periphery of the somatic field. Paracyrtophoron tropicum nov. spec., the type of the new genus, can be recognized by the combination of the following characters: cell size about 150-175×70-90μm in vivo; elliptical to kidney-shaped in outline, dorsoventrally flattened about 2.5:1; conspicuous cortical granules; one canal-like depression extending from postoral area to subcaudal region of cell; ca. 90 somatic kineties; 12-16 nematodesmal rods; one or two terminal fragments on dorsal side. Aegyria rostellum is characterized by the following features: size about 90-150×40-70μm in vivo, triangular or ear-shaped body with broad anterior end, having a rostriform structure and pigment spots, 56-63 somatic kineties, one preoral kinety, three or four circumoral kineties, and 32-42 nematodesmal rods. Based on previous and current studies, the definition for the genus Aegyria is updated: body dorsoventrally flattened; oral ciliature consisting of one preoral and several circumoral kineties; podite located in posterior ventral region and surrounded by somatic kineties; no obvious gap between right and left somatic kineties; postoral and left somatic kineties progressively shortened posteriorly from right to left. Additionally, two new combinations were proposed.     

Bromeliothrix metopoides,a boom and bust ciliate (Ciliophora,Colpodea) from tank bromeliads

We investigated the recently described colpodid ciliate Bromeliothrix metopoides in a series of laboratory experiments to reveal the environmental factors that constrain this species to its peculiar habitat, i.e. the tanks of bromeliads. Our results demonstrated that the various life stages of this ciliate (bacterivorous theronts and microstome trophonts, flagellate-feeding macrostomes) have specific demands in terms of food quality and quantity. Bromeliothrix required a high food threshold (>1.4 mg C L^?1) in order to thrive. Food quality also affected resting cyst formation of B. metopoides when the experimental containers dried out. Its maximum growth rates (μ_max = 4.71 d^?1, i.e. 6.8 doublings d^?1) belong to the highest ones recorded thus far for free-living ciliates. The pH niche of B. metopoides was relatively wide (pH ～4 to >9) under optimal food conditions. However, its high sensitivity to unfavourable environmental conditions let the population collapse within several hours. We conclude that B. metopoides is a boom and bust ciliate that is specifically adapted to its peculiar habitat but virtually unviable in other environments.     

In vitro culture technique for Cryptocaryon irritans, a parasitic ciliate of marine teleosts

A medium for the in vitro culture of Cryptocaryon irritans, which is an obligatorily parasitic ciliate of marine teleosts and causes 'white spot disease', was developed. The medium consisted of a layer of cultured fish cells (FHM), with an agarose gel layer covering the cell layer. The agarose gel contained 0.22% agarose, 10% fetal calf serum, 100 I.U. ml(-1) Penicillin G potassium and 100 microg ml(-1) streptomycin sulphate. Theronts of C. irritans transformed to trophonts and grew to 180 microm in mean length in the medium, although they gradually decreased in number. When trophonts fully developed in medium were transferred into seawater 4 d after inoculation, approximately 70% of them transformed to encysted tomonts and released theronts. When fish were challenged with theronts obtained from in vitro-raised parasites, approximately 40% of the theronts were recovered from fish, indicating comparative infectivity of in vitro-raised theronts to those of in vivo-raised theronts. This is the first report that C. irritans fully developed in vitro and its entire life cycle was completed without a host fish.     

Morphology and morphogenesis of a new marine cyrtophorid ciliate, Hartmannula sinica nov. spec. (Protozoa, Ciliophora, Cyrtophorida) from China

The living morphology, infraciliature and morphogenesis of a new marine cyrtophorid ciliate, Hartmannula sinica nov. spec., collected from Qingdao, north China, have been investigated. The new species is characterized by: size in vivo 90–130×40–50 μm, body long elliptical in outline, cilium-free field covered with a conspicuous alveolar layer; 24–31 ventral kineties, the rightmost 6–9 of which extend apically; 20–24 nematodesmal rods; about 15 sparsely distributed contractile vacuoles; a yellowish pigment spot is always present near the anterior tip of the cell. Morphogenetic events exhibit a pattern, which is homologous with that of related cyrtophorids. The main features are as follows: (1) preoral and circumoral kineties of opisthe develop from the oral primordium that forms in mid-body from sections of 3 postoral kineties, while parental preoral and circumoral kineties are retained; (2) parental cytostome and nematodesmal rods are resorbed in middle divisional stages and then replaced by newly formed structures; (3) the heteromerous macronucleus unifies in the late divisional stage.     

Morphological and phylogenetical studies on a new soil hypotrich ciliate: Kahliella matisi spec. nov. (Hypotrichia,Kahliellidae)

The morphology, ontogenesis, encystment, and 18S rRNA gene sequence of a new soil hypotrich ciliate, Kahliella matisi, were studied. Main characteristics of K. matisi are: (1) two short and six longitudinal cirral rows right of the adoral zone of membranelles and four longitudinal rows left of it; (2) three dorsal kineties, of which kinety 1 extends along the left cell margin, kinety 2 runs in a slightly sigmoidal line, and kinety 3 is distinctly shortened posteriorly. Ontogenesis is similar to that in congeners, especially in the development of the marginal rows and long dorsal kineties, the preservation of some old cirral rows after division, and the direction of the neokinetal wave. However, there are some peculiarities: (1) reorganization of the proximal parental adoral membranelles; (2) splitting of opisthe's anlage II into the cirral streak II and III; and (3) formation of the parental cirral row R3 from anlagen IV and V. During encystment, the body diminishes and becomes globular, the nuclear apparatus is reorganized, and the ciliature is resorbed. In our molecular phylogenies, the family Kahliellidae is polyphyletic and the position of K. matisi is rather poorly resolved, indicating a relationship with oxytrichids.     

Planeticovorticella finleyi n.g., n.sp. (Peritrichia, Vorticellidae), a planktonic ciliate with a polymorphic life cycle

Abstract. Free-swimming trophonts of a sessiline peritrich ciliate were discovered in plankton samples from the Rhode River, Maryland, and main-stem Chesapeake Bay. Cultures revealed that the species comprises both free trophonts that swim with their peristomial cilia and sessile trophonts that attach to substrates with a contractile, helically-twisted talk. Trophonts with a short, rigid stalk or no definite stalk also were seen in culture. Binary fission of free-swimming trophonts usually produced a pair of trophonts attached scopula to scopula by a short, rigid stalk. These persisted for some time as distinctive, spinning doublets before their stalks broke and they separated. Binary fission of free-swimming trophonts also yielded trophont-telotroch pairs that stayed together for only a short time. Telotrochs from these pairs were presumably the source of attached trophonts. Conjugation occurred in both free and attached trophonts. Formation of microconjugants involved at least 2 successive divisions of a trophont. Possession of a helically-twisted, contractile stalk placed the peritrich in the family Vorticellidae, but its unique combination of life-cycle stages marks it as a new genus and species, Planeticovorticella, finleyi The morphology and life cycle of P. finleyi raise questions about the present classification of sessiline peritrichs and suggest that it may be at least partly artificial. Stalkless planktonic peritrichs that swim with their oral cilia as do trophonts of P. finleyi may have evolved from sessile ancestors by an alteration in the life cycle that created unstable clusters of trophonts on a single parental stalk. Free-swimming trophonts would originate from breakup of these clusters.     

The Life Cycle and Morphology of the Apostomatous Ciliate,Hyalophysa chattoni n. g., n. sp.*

SYNOPSIS. A new apostome ciliate was discovered in collections at Friday Harbor, Washington and the San Francisco area. All stages of the life cycle were studied in both living and stained condition. Dormant encysted stages (phoronts) occur on the gills of Pagurus hirsutiusculus. Excystation occurs in synchrony with the molting of the host yielding the trophic stage (trophont), which feeds on the exuvial fluids trapped in the crab's cast-off exoskeleton. The trophont becomes greatly enlarged as a result of feeding, and the cytoplasm and organelles become compressed into a thin cortical layer. Each fully grown trophont encysts (becoming a tomont) as a prelude to repeated binary fission, which results in the release of actively motile offspring (tomites). These disperse and promptly resume the encysted phoront stage on the host's gills. The Chatton-Lwoff silver impregnation method revealed that all stages of the life cycle have nine somatic kineties. In the trophont stage they are accompanied by an anterior ventral field of scattered clumps of kinetosomes. During conjugation the partners attach by their ventral surfaces between kineties 1 and 9 and at the left of the ventral field. The tomite stage was stained with Protargol. In addition to the characteristic features of the foettingeriid tomite also revealed by the Chatton-Lwoff method, Protargol revealed the following heretofore undescribed morphological features: a short row of kinetosomes immediately anterior to the ogival field; a line paralleling the left margin of the field; the continuity of kinety 8 with falciform field 8; the entrance of kinety 9 into the mouth and its ending against the rosette (an enigmatic organelle characteristic of Foettingeriinae). Feulgen stains showed that the chromatin in the macronucleus is dispersed in aggregates whose size and number vary with the stage of the life cycle. The major period of chromatin synthesis appears to be during the early tomont stage, when Feulgen-positive material increases visibly in amount and intensity of staining. This apostome ciliate was characterized as a new genus on the basis of the infraciliature of the trophont stage, its conjugation with ventral surfaces appressed, and its life cycle. It is named Hyalophysa (hyalo = glassy, physa = bubble) chattoni.     

The Life Cycle of the Histophagous Ciliate Tetrahymena corlissi Thompson, 1955*

The life cycle of Tetrahymena corlissi Thompson, 1955, is described from organisms fed on tissue of the oligochaete Enchytraeus. The trophont stage usually divides twice either while free-swimming or encysted as a tomont. The tomont stage apparently occurs only when the trophont is removed from the “conditioned” tissue environment. The time to completion of division is constant and determined at the onset of exposure to tissue. The number of divisions is a function of the amount of tissue ingested. Tomites differentiate after the divisions as active theronts. This dispersal stage transforms to a trophont when tissue is ingested. If tissue is absent, the theronts become smaller, eventually settling on the substrate as immotile pyriform resting theronts, with a small proportion of the resting theronts encysting within a delicate cyst wall. When stimulated chemically or mechanically, the resting theronts transform to active theronts. If these active theronts ingest tissue, they transform to immature trophonts, initially incapable of division. Life cycle and morphologic dissimilarities among T. corlissi, T. bergeri, and T. rostrata are presently used to distinguish among these species.     

Re-establishment of the cyrtophorid genus Coeloperix Deroux,nov. gen., with a description of Coeloperix sleighi nov. spec. (Protozoa,Ciliophora, Cyrtophorida)

The cyrtophorid genus Coeloperix, which has remained invalid for over 20 years, is re-established. This taxon is characterized by Lynchellids without podites on the ventral side; somatic kineties making no noticeable naked gap between left and right areas; pre- and post-oral kineties completely separated; two terminal fragments; perioral kineties consisting of one continuous anterior and two detached posterior rows; with cross-striated band around perimeter between ventral and dorsal surfaces. Based on this definition, two nominal species formerly placed in the invalid genus have been included again in Coeloperix: Coeloperix dirempta (Deroux, 1970) nov. comb. [synonym: Lynchella dirempta; Deroux, 1970], C. aspidisciformis (Kahl, 1933) nov. comb. [syn. Lynchella aspidisciformis; Kahl, 1933]. Another two morphotypes C. eforiana (Tucolesco, 1962) nov. comb. [syn. Lynchella eforiana; Tucolesco, 1962] and C. lynchelliformis (Borror, 1972) nov. comb. [syn. Chlamydodon lynchelliformis; Borro, 1972] have been transferred into the new genus. The morphology of living cells and infraciliature of a new species, C. sleighi nov. spec., isolated from the coastal area of China, have been investigated. It is diagnosed by: size about 40×30 μm in vivo; consistently 4 preoral and 15–16 postoral kineties; 12–16 nematodesmata; cross-striated band with two separations in the equatorial area; 3–4 (usually 3) finger-like tentacles on the ventral side; macronucleus ellipsoidal; two contractile vacuoles diagonally located; marine habitat.     

Establishment of a new amphileptid genus, Apoamphileptus nov. gen. (Ciliophora, Litostomatea, Pleurostomatida), with description of a new marine species, Apoamphileptus robertsi nov. spec. from Qingdao, China

A new pleurostomatid genus Apoamphileptus is described, which is diagnosed as: Belonging to the Amphileptidae with spica on right side; on each side of the cell, a single perioral kinety, which encircles the cytostome and does not extend to the posterior end of the cell; somatic kineties of both sides near ventral margin shortened and forming a postoral suture; two to several extra fragments with densely arranged dikinetids located in anterior portion of left side. As the type species, the morphology and infraciliature of Apoamphileptus robertsi nov. spec., isolated from a shrimp-farming pond near Qingdao (Tsingtao), China, have been investigated using living observations and the protargol silver impregnation method. The diagnosis for this new species is: Apoamphileptus 90-180 x 30-60 microm in vivo, body elongate pyriform-shaped and slightly flattened; with one cross-striated band along the cytostome; 2-6 (generally 4) large macronuclear nodules, one micronucleus; 33-43 right somatic kineties; left side 6-8 kineties; two extra anterior fragments on left side; about 13 contractile vacuoles dispersed throughout whole body; extrusomes absent or not recognizable; marine habitat. Some morphologically related morphotypes are discussed and tabulated. Regarding the pattern of infraciliature and other morphological features, the well-described fresh-water species, Amphileptus claparedii Stein, 1867 is believed to be a member of this new genus, hence a new combination is suggested: Apoamphileptus claparedii (Stein, 1867) nov. comb.     

Functional Ecology of the Ciliate Glaucomides bromelicola,and Comparison with the Sympatric Species Bromeliothrix metopoides

We investigated the ecology and life strategy of Glaucomides bromelicola (family Bromeliophryidae), a very common ciliate in the reservoirs (tanks) of bromeliads, assessing its response to food quality and quantity and pH. Further, we conducted competition experiments with the frequently coexisting species Bromeliothrix metopoides (family Colpodidae). In contrast to B. metopoides and many other colpodean ciliates, G. bromelicola does not form resting cysts, which jeopardizes this ciliate when its small aquatic habitats dry out. Both species form bactivorous microstomes and flagellate‐feeding macrostomes. However, only G. bromelicola has a low feeding threshold and is able to adapt to different protist food. The higher affinity to the local bacterial and flagellate food renders it the superior competitor relative to B. metopoides. Continuous encystment and excystment of the latter may enable stable coexistence of both species in their natural habitat. Both are tolerant to a wide range of pH (4–9). These ciliates appear to be limited to tank bromeliads because they either lack resting cysts and vectors for long distance dispersal (G. bromelicola) and/or have highly specific food requirements (primarily B. metopoides).     

Description of a new marine cyrtophorid ciliate, Dysteria derouxi nov. spec., with an updated key to 12 well-investigated Dysteria species (Ciliophora, Cyrtophorida)

The morphology of living cells and the infraciliature of a new marine cyrtophorid ciliate, Dysteria derouxi nov. spec., collected from the coastal area of Qingdao, China, have been investigated. This species is characterized by: size about 100×40 μm in vivo, body rectangular in outline; 8 ventral kineties in the right field, of which the right-most 3 extend dorso-apically; 6–9 short kineties in the left equatorial field; two ventral contractile vacuoles; and marine habitat. Based on the data of morphology and infraciliature, an updated key to 12 Dysteria species is supplied.     

Gymnodinioides pitelkae n. sp. (Ciliophora,Apostomatina) from the littoral amphipod,Marinogammarus obtusatus,a trophont with remnants of the tomite's infraciliature

The apostome genus, Hyalophysa, is a symbiont on most littoral decapods in the US, but no other crustacean orders have been investigated. When exuvia of the amphipod Marinogammarus obtusatus were examined, they contained swimming trophonts whose characteristics revealed by Chatton–Lwoff stains describe a new species of Gymnodinioides. Its unique characteristic is the retention in the trophont of a polykinety similar to the falciform field of the tomite, the non-feeding, migratory microstome stage common to apostome genera. The trophont's anterior pattern of kineties also resembles that of the tomite. Speculations that speciation in Gymnodinioides may result from isolation on different hosts, changes in the internal feeding apparatus, delays or mishaps during morphogenesis, or habitat changes affecting the host must consider the case of G. pitelkae. The tomite may not respond to the signals from its premoult host to change to the macrostome infraciliature although the feeding apparatus is formed.     

Ophryoglena hemophaga n. sp. (Ciliophora: Ophryoglenidae): a parasite of the digestive gland of zebra mussels Dreissena polymorpha

Ophryoglena hemophaga n. sp. is described from a freshwater Dreissena polymorpha population in the Rhine delta of the Netherlands. This is the first ophryoglenine species (order Hymenostomatida, suborder Ophryoglenina) recorded as a molluscan parasite. As is typical of ciliates in the suborder Ophryoglenina, O. hemophaga exhibits a polymorphic life history with cystment and reproduction by palintomy. Trophonts were observed within digestive gland lumina, and zebra mussel hemocytes were present in some of their digestive vacuoles. The presence of a single, longitudinal tract of multiple contractile vacuoles represents its most unique feature and distinguishes it from all other described Ophryoglena spp. The number of somatic kineties of O. hemophaga (range 100 to 124) is also distinguishing as it is one of the lowest for [corrected] an Ophryoglena sp. Other characteristics of this species include: ovoid to elongate trophonts 96 to 288 microm in length, with an elongate macronucleus 41 to 65 microm in length; tomonts 50 to 150 microm in diameter producing a clear mucous cyst envelope, whose thickness is approximately half of the tomont diameter; elongated theronts 96 to 131 microm in length which emerge after 1 to 3 cell divisions taking 36 to 48 h at 20 +/- 3 degrees C. Protomonts and theronts are, respectively, negatively and positively phototactic--characteristics that likely aid in maintenance of infection in zebra mussel populations.