Description of the Infraciliature and Morphogenesis in the Ciliate Urotricha ondina N. Sp. (Prorodontida, Urotrichidae)

Recent works on prostomatid ciliates show that some genera of this group have a differentiated oral infraciliature and that their stomatogenesis during division involves the proliferation of only a few somatic kineties. These findings have significant implications regarding the iaxonomic status of these genera and also on the terminology used for the oral structures. In Urotricha ondina , the oral infraciliature consists of (1) a paroral kinety formed of paired kinetosomes that encircle the cytostome at the anterior pole of the cell and (2) 3 adoral organelles, each formed of 2 rows of kinetosomes, ventral in position and obliquely disposed, lying above 3 short somatic kineties that do not reach the anterior pole of the cell. This oral ciliature —formerly known as the corona and brosse, respectively—originate during stomatogenesis from the proliferation of 4 somatic kineties that lie posterior to the adoral organelles of the parental cell.     

Light and Electron Microscopic Observations on the Heterotrich Ciliate Climacostomum virens

SYNOPSIS. Alveolar membranes and an epiplasm exist under the cell membrane of the noncontractile heterotrich ciliate Climacostomum virens. Postciliary microtubular ribbons join at the right of each somatic kinety to form a Km fiber. Two transverse microtubular fibers occur per kinetosomal pair. A myonemal network interconnects the kinetosomal bases intrakinetally and interkinetally. Ultrastructural comparisons are made between the contractile and noncontractile heterotrichs.
The buccal cortex consists of an adoral zone of membranelles, a peristomal field, a buccal tube, the apical membranelles, and a haplokinety. The kineties of the peristomal field and buccal tube are rows of paired kinetosomes, with a postciliary ribbon of microtubules arising from the posterior kinetosome of each pair, and a transverse ribbon and an oblique ribbon from the anterior kinetosome. No Km fibers exist in this region. The haplokinety is a collar of paired kinetosomes surrounding the cytostome; a postciliary microtubular ribbon descends from each kinetosomal pair into the cytostomal region. Ultrastructural details of the buccal cortex of C. virens and other heterotrichs are compared. The nemadesmata which lie under the membranelles are implicated in the body bending of C. virens.
Algae endosymbiotic in the cytoplasm of C. virens are described.     

Redescription of the little-known marine ciliate,Stichotricha marina Stein, 1867 (Ciliophora,Hypotrichida) from the mantle cavity of cultured scallops

The morphology and infraciliature of an ectocommensal ciliate, Stichotricha marinaStein, 1867, isolated from the mantle cavity of marine scallops near Qingdao, China were redescribed using the protargol impregnation method. Based on the present studies, a new diagnosis is suggested: body twisted and flexible, in vivo about 160–200 μm with elongated body shape; peristomial field narrowed and neck-like, about half of body length; ca. 70 adoral membranelles, two clearly differentiated frontal cirri; 27–41 buccal cirri, arranged in one long row along with buccal field; transverse cirri absent; three complete dorsal kineties and three caudal cirri. Consistently two macronuclear nodules, and gelatinous lorica tube-like; marine habitat.     

盾圆双眉虫与伪寡毛双眉虫的形态学重描述(原生动物,纤毛门)

研究对采自青岛沿海的两种海洋纤毛虫-盾圆双眉虫与伪寡毛双眉虫做了形态学重描述。盾圆双眉虫与前人所报道的种群具有十分相似的纤毛图式,但在额-腹棘毛分布、大核片段、小膜及背触毛数目等方面表现出细微的变异性。此外,该青岛种群个体较小。统计学比较还表明,迄今缺乏研究的一海洋种,泥生双眉虫极可能为盾圆双眉虫(Diophrys scutum)的同物异名。伪寡毛双眉虫(Diophrys apoligothrix)为一新近报道的罕见种,研究基于新采集种群对其进行了补充性观察和描述。       

Redescription of Phacodinium metchnikoffi (Ciliophora, Hypotrichida): General Morphology and Taxonomic Position

ABSTRACT Living and stained specimens of Phacodinium metchnikoffi , collected near Madrid, Spain, were studied under light microscopy. Infraciliature was stained using a silver-impregnation procedure. The somatic infraciliature is composed of a relatively small number of discontinuous kineties, formed by groups of few kinetosomes (pallets). The buccal ciliature is composed of an adoral zone of membranelles and a paroral formation otherwise unknown in ciliates, with many short kineties, which lie on a rigid stem. We propose that P. metchnikoffi is a primitive hypotrich and, consequently, we present a new classification system for hypotrichs.     

New Aspects of the Morphology of Pleurotricha lanceolata (Ciliophora, Hypotrichida): Cirral and Membranellar Patterns and Fibrillar Systems

In Pleurotricha lanceolata, the ventral somatic infraciliature presents 13 frontoventral cirri, 5 transverse cirri, one row with 18–19 left marginal cirri and two rows of right marginal cirri of different length. On the dorsal side there are six longitudinal rows of dorsal bristles, four of them bipolar and the other two less than half body length. The oral infraciliature includes the adoral zone of membranelles, with 45–55 membranelles of three or four rows of kinetosomes each, and two undulating membranes (paroral and endoral membranes), each with two rows of kinetosomes. Some structures of the oral and somatic fibrillar systems have also been examined and are similar to those described in other species of hypotrichous ciliates.     

Morphogenèse de Régénération chez le CiliéCondylostoma magnum (Spiegel): Etude ultrastructurale

SYNOPSIS Cortical events occurring in the course of regeneration in Condylostoma magnum (Spiegel) were studied by electron microscopy. The zone of regeneration is very rich in vacuoles and small vesicles formed from the plasma membrane. Multiplication of kinetosomes starts on the left side of kineties in the V-shaped left ventral area, normally implicated in stomatogenesis, at the level of the anterior kinetosomes of the somatic pairs. The proliferation proceeds by the appearance of young kinetosomes most often orthogonal to the old ones. This process of multiplication is very rapid and terminates in the formation of an “anarchic field” in which one observes that: (a) the newly formed kinetosomes do not possess all the associated postciliary fibers; and (b) when these fibers are detected, the kinetosomes are not in the same orientation. Differentiation of the adoral organelles takes place in the left part of the field (left primordium) by an alignment of the kinetosomes into 2 rows for each organelle (oriented perpendicularly to the antero-posterior axis of the ciliate), of which only one has the postciliary fibers. Ciliatogenesis occurs in numerous kinetosomes of the anarchic field; in certain kinetosomes it is achieved at the onset of their arrangement into organelles and is concomitant with growth of the nematodesmata. The 3rd (anterior) row of the organelles, the interkinetosomal desmata, and connections among neighboring organelles appear only secondarily. Differentiation of the paroral cilia occurs later. It takes place in the interior of the primordium, whose organization is primarily anarchic, and is accompanied by a progressive resorption of the major part of the newly formed kineties. Numerous kinetosomes of the right field have the associated postciliary fibers, which are not found at the level of the regenerated “polystichomonad” (paroral organization characteristic of C. magnum). Finally, the formation of new kinetosomes within a somatic kinety at the time of its elongation is described.     

Redescription of Favella ehrenbergii (Claparède and Lachmann, 1858) Jörgensen, 1924 (Ciliophora: Choreotrichia), with Phylogenetic Analyses Based on Small Subunit rRNA Gene Sequences

ABSTRACT. The identification of Favella ehrenbergii, a marine planktonic ciliate, has largely been based on its lorica features. This approach is potentially problematic given the polymorphic lorica during this organism's life cycle. We isolated a population of F. ehrenbergii from the coastal waters of Incheon, Korea, and revealed its infraciliature using the protargol staining method. Phylogenetic analysis based on small subunit rRNA gene sequences was also performed. Results showed that this population possessed 16 collar membranelles (CM) and about 100 somatic kineties. These features are highly conserved, even in later dividers. As such, the number of CM and somatic kineties can be used as key characteristics for identification of Favella species.     

Redescription of Phacodinium metchnikoffi (Ciliophora, Hypotrichida): general morphology and taxonomic position.

Living and stained specimens of Phacodinium metchnikoffi, collected near Madrid, Spain, were studied under light microscopy. Infraciliature was stained using a silver-impregnation procedure. The somatic infraciliature is composed of a relatively small number of discontinuous kinetics, formed by groups of few kinetosomes (pallets). The buccal ciliature is composed of an adoral zone of membranelles and a paroral formation otherwise unknown in ciliates, with many short kineties, which lie on a rigid stem. We propose that P. metchnikoffi is a primitive hypotrich and, consequently, we present a new classification system for hypotrichs.     

Redescription of the rare heterotrichid ciliate,Copemetopus subsalsus Villeneuve-Brachon, 1940

The morphology and infraciliature of the rare heterotrichid ciliate Copemetopus subsalsus Villeneuve-Brachon, 1940 were studied in live and protargol-impregnated specimens and also by scanning electron microscopy. It is characterized by a dumbbell-shaped macronucleus, a specific dorsal brush cilia, an oblique peristome, and a distinct S-shaped adoral zone of membranelles equipped with whip-shaped anterior adoral membranelles.     

Evidence for Hymenostome Affinities in an Apostome Ciliate

The functional mouth of exuviotrophic apostome ciltates appears only after an elaborate metamorphosis that begins at the onset of the molting of their crustacean hosts. In the tomite. a non-feeding migratory stage, a mid-ventrai depression at the origin of kineties x, y and z has been misidentified as the cytostome. Studies of fine structure and morphogenesis identify the true but nonfunctional cytostome—the subapiral lateral canal —and the falciform and ogival fields as the adoral ciliature. The anterior row of barren kinetosomes that parallels on the right the anterior third of the lateral canal is actually the infraciliature of a paroral. 2 rows of barren staggered kinetosomes. The canal itself is a narrow tube, its walls partially lined with microtubules. It begins 2–3 μm from the apex of the body and passes between falciform field 9 and the ogival field to end near the end of the ogival field. The fine structure of the infraciliature of the falciform and ogival fields differs markedly from that of the somatic kineties. In the host's early pre-molt stages, the paroral migrates across the ventral surface of the encysted phoront and is accompanied by the microtubules of the lateral canal. The anterior end of falciform field 9 disorganizes into scattered kinetosomes, the trophont's anterior field of kinetosomes, but the posterior end migrates in an arc across the anterior ventral surface and remains as kinety a located near the angle where kinety 1 sharply par ra continues posteriad ind dorsad to the posterior limit of the extended cytostome. At the end of metamorphosis it sinks into The cytoplasm and disappears. The completion of the extended cytostome, the functional mouth, marks the termination of the microstome-macrostome transformation. The fine structure of the infraciliature and microtubular elements making up the macrostome and the evocation of the microstome-macrostome transformation in the presence of specific foods suggest that apostome ciliates any more properly be a suborder of Hymenostomatida rather than a subclass of Oligohymenophorea.     

Morphogenesis in the Heterotrich Ciliate Climacostomum virens. II. Oral Development During Regeneration1

The regeneration (RG) of the oral apparatus (OA) by Climacostomum virens (Ciliophora, Heterotrichida) is examined by estimation of the ability of live cells to ingest food as well as by Nomarski interference contrast microscopy, bright field microscopy of protargol-stained specimens, and by scanning electron microscopy. When placed in a 6% (w/v) urea solution for ～ 2 min 10 sec, populations of 10,000–100,000 cells shed a large part of their OA. In more than 90% of the cells that shed, the discarded segment is comprised of the apical membranelles, most of the adoral membranelles, and of a variable part of the buccal tube. After washing and incubation at 26°C, 50% of the cells regenerate a functional OA in 4 h 47 min, and after 5 h 26 min, 90% of the cells are able to ingest food. At any given moment during the process, 50–90% of the cells are morphologically in the same stage of RG. Seven stages (among which three are divided into two substages) of RG are defined. The process begins by the disorganization of the remnant oral structures. Concomitantly, kinetosomes multiply along the kineties of the zone of discontinuity and form the longitudinally oriented oral primordium. The latter gives rise to the adoral primordium, which rapidly produces the adoral zone of membranelles (AZM), and to the paroral primordium, which subsequently forms the apical membranelles, the buccal peristomial kineties, and the paroral kinety. Morphogenetic movements lead to incurvation of the AZM and the frontal field and to invagination of the buccal tube.     

Updating the Trachelocercids (Ciliophora, Karyorelictea). I. A Detailed Description of the Infraciliature of Trachelolophos gigas N. G., N. Sp. and T. filum (Dragesco & Dragesco-Kernéis, 1986) N. Comb

ABSTRACT. Trachelolophos gigas n. g., n. sp. and T. filum (Dragesco & Dragesco-Kernéis, 1986) n. comb. (basionym: Tracheloraphis filum) were discovered in the mesopsammon of the French Atlantic coast at Roscoff. Their morphology and infraciliature were studied in live and protargol impregnated specimens. The new genus, Trachelolophos, belongs to the family Trachelocercidae and is unique in having a conspicuous ciliary tuft, which is very likely a highly modified brosse, in the oral cavity. The two species investigated have a very similar infraciliature, differing only in morphometric characteristics and in the nuclear configuration. The entire somatic and oral infraciliature consists of dikinetids which have both basal bodies ciliated or only the anterior or posterior ones, depending on the region of the cell. The right side is densely and uniformly ciliated. Its kineties extend onto the left side to the glabrous stripe, where an anterior and posterior secant system are formed, reducing the number of kineties in the narrowed neck and tail region. The left side bears a narrow glabrous stripe bordered by slightly irregularly arranged dikinetids having rather stiff cilia (bristles), possibly forming an uninterrupted, prolate ellipsoidal (bristle) kinety as indicated by their ciliation. The bristle kinety commences subapically at the right margin of the glabrous stripe, extends posteriorly, then anteriorly at the left, to end up at the right margin again. The dikinetids of the right posterior portion of the bristle kinety have the posterior basal bodies ciliated, whereas the anterior basal bodies are ciliated in its left and right anterior portion. The ends of the bristle kinety meet distinctly subapically at the right margin of the glabrous stripe, as indicated by the diametrically opposed ciliation of the dikinetids. The anterior region (head) of the cell bears a distinct circumoral kinety composed of very regularly arranged dikinetids, associated with nematodesmata forming an oral basket together with the nematodesmal bundles originating from the oralized somatic dikinetids at the anterior end of the somatic kineties. The systematics of trachelocercid ciliates are briefly reviewed and discussed.     

Pelagostrobilidium liui n. sp. (Ciliophora,Choreotrichida) from the Coastal Waters of Northeastern Taiwan and an Improved Description of Pelagostrobilidium minutum Liu et al., 2012

The number of somatic kineties in Pelagostrobilidium ranges from 4 to 6 according to the present state of knowledge. This study investigates Pelagostrobilidium liui n. sp. using live observation, protargol stain, and small subunit rDNA data sequencing. Pelagostrobilidium liui n. sp. is characterized by having a spherical‐shaped body, four somatic kineties, with kinety 2 spiraled around the left side of body, about six elongated external membranelles, and invariably no buccal membranelle. It differs from its most similar congener, Pelagostrobilidium minutum Liu et al., 2012 , in (i) cell shape; (ii) macronucleus width; (iii) oral apparatus; (iv) anterior orientation of kinety 2; (v) location where kinety 2 commences; (vi) arrangement of kinety 1; (vii) distance between the anterior cell end and the locations where kineties commence; and (viii) the presence of 12 different bases (including two deletions) in the small subunit rDNA sequences. The diagnosis of P. minutum Liu et al., 2012 is also improved to include the following new characteristics: invariably four somatic kineties; kineties 2 and 4 alone commence at the same level; kinety 2 originates from right anterior cell half on ventral side, extends sinistrally posteriorly, over kinety 1, around left posterior region, terminates near posterior cell end on dorsal side; kinety 1 commences below anterior third of kinety 2.     

Buccal and Somatic Infraciliature of Lagynus elegans (Engelmann, 1862) Quennersted, 1867 (Ciliophora, Prostomatea): Remarks on its Systematic Position

The somatic and buccal infraciliature of Lagynus elegans are described, and aspects of its division and conjugation are reported. Its somatic infraciliature is made up of 37–46 meridianal kineties composed of isolated kinetosomes that have thick and long kinetodesmal fibers. In the anterior zone of the cell, the circumoral infraciliature can be observed: it is composed of short, slightly oblique kinetal segments, which are formed of three kinetosomes each. The brosse of this species consists of 3 or 4 groups that possess 4 to 6 ciliated kinetosomes each; these kinetosomes lack kinetodesmal fibers. On the apical pole of the cell, surrounding the oral opening, a crown of nematodesmata is observed; these nematodesmata are connected to each other by a fibrillar structure. Taking into account these features, we propose that this genus be transferred from the order Prostomatida to a new family, Lagynidae, of the order Prorodontida.     

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.     

Rasterelektronenmikroskopische und biometrische Untersuchungen über die Variabilität der Form, Struktur und Größe des Gehäuses einiger limnischer Tintinnina (Protozoa, Ciliophora)

The loricae of the fresh-water Tintinnina Codonella cratera, Tinitinnidium fluviatile , and Tintinnopsis cylindrata were investigated for their variability in shape, structure, and size, using scanning electron microscopy and variance analysis. The intrastrain variability of length and width of the loricae is significantly smaller than the interstrain variability. The shells are shorter in autumn than in spring. The lorica of C. cratera consists of biogenic and non-biogenic flakes, irregularly cemented by a substance which is released from the organism. Building of the shell is not restricted to the time of binary fission. T. fluviatile and T. cylindrata have soft and sticky loricae which are heavily agglutinated by various biogenic and non-biogenic particles. The material used for lorica-building and/or agglutination depends on environment and season. There is a relationship between the structure of the lorica and the degree of eutrophication in the lake. The significance of these findings for paleolimnology and taxonomy and the function of the lorica in fresh-water Tintinnina are discussed.     

Morphology and infraciliature of Holosticha bradburyae nov. spec. (Ciliophora,Hypotrichida) from the Yellow Sea,China

The living morphology and infraciliature of a new marine hypotrichous ciliate, Holosticha bradburyae nov. spec., collected from the coastal water off Qingdao (Tsingtao), China, are investigated. This species is characterized by: body size 150–320 × 25–75 m with brownish to dark brown cell colour, ca. 53 adoral membranelles and 1 anteriorly positioned buccal cirrus; 3 frontal, 2 frontoterminal and 20–26 transverse cirri; midventral rows comprising 27-32 pairs of cirri; one conspicuous gap always present between anterior and posterior parts of AZM, and 2–5 distinctly elongated membranelles are always present at the posteriormost end; cortical granules conspicuous, round and flattened with central depression, arranged in about 10 lines on dorsal side; 28–33 irregularly arranged macronuclear nodules; 9–11 complete dorsal kineties; caudal cirri absent.