Contractile Vacuole Research Articles

Morphological and Molecular Description of Three New Species of the Cyrtophorid Genus Chlamydodon (Ciliophora, Cyrtophoria)

This study investigates the morphology and molecular characteristics of three new cyrtophorid ciliates isolated from China seas: Chlamydodon salinus n. sp., Chlamydodon caudatus n. sp., and Chlamydodon paramnemosyne n. sp. Of these, C. salinus n. sp. differs from its congeners through a combination of body size, a cross-striated band that is not continuous, the presence of 30-34 somatic kineties, 11-15 nematodesmal rods, and 13 contractile vacuoles. Chlamydodon caudatus n. sp., meanwhile, is characterized by having a conspicuous tail, a continuous cross-striated band, 34-40 somatic kineties, about 15 contractile vacuoles, and 20-24 nematodesmal rods. Compared with other Chlamydodon species, the third new one, C. paramnemosyne n. sp., could be identified by its continuous cross-striated band, 16-18 somatic kineties, 5 contractile vacuoles, and 9-12 nematodesmal rods. Based on the sequence of the small subunit (SSU) rRNA gene, the phylogeny of these three new species was analyzed, indicating that they all clustered with other congeners to form a monophyletic assemblage. Based on previous studies and the present work, a brief revision of the genus Chlamydodon is supplied, and a key to aid the identification of Chlamydodon species is given.

Three New Loxophyllum Species (Ciliophora: Pleurostomatida) from China with a Brief Review of the Marine and Brackish Loxophyllum Species

Recent studies indicate that there is a high diversity of pleurostomatid ciliates in the coastal waters of China. Here, three new congeners of Loxophyllum, L. caudatum sp. n., L. rugosum sp. n., and L. chinense sp. n., are described following observations of live cells and protargol-impregnated specimens. All three species usually have two macronuclear nodules and prominent warts along the dorsal margin formed by clustered extrusomes. In addition, L. caudatum sp. n. is characterized by its long conspicuous tail, dot-like cortical granules, 4 or 5 left and 9 or 10 right kineties, and a single subterminal contractile vacuole. Loxophyllum rugosum sp. n. is distinguished by possessing three prominent ridges on the left side, 7-11 right and 5-7 left kineties. Loxophyllum chinense sp. n. is characterized by having several contractile vacuoles distributed along the ventral margin, 13-18 right and 6-8 left kineties. The small subunit ribosomal DNA (SSU rDNA) sequence similarities among six congeners range from 96.46% to 99.94%. Phylogenetic trees based on the SSU rDNA sequences indicate that all Loxophyllum spp. form a well-supported monophyletic group. A brief review of the marine and brackish Loxophyllum species is supplied and one new combination, Litonotus multiplicatus (Kahl 1931) comb. n. (basionym Loxophyllum multiplicatum Kahl 1931), and one new name, Litonotus dragescoi nom. n. (basionym L. fasciolatus Dragesco 1966), are suggested.

First report of Epistylis unioi Gong 1986 (Sessilida: Epistylididae) infecting fry of Pelteobagrus fulvidraco in Hubei, China

The peritrich Epistylis unioi Gong, 1986 was collected from fry of Pelteobagrus fulvidraco during parasite surveys at Hon-ghu Lake Fish Hatchery, Hubei Province, central China in May 2010 and redescribed. Some revisions were done basedon live, silver-impregnated, and SEM specimens. The zooid is elongated and somewhat vase-like in shape, measuring56–88 × 22–38 µm in vivo. A single contractile vacuole is apically located slightly below the peristome disc. The macro-nucleus is horseshoe-shaped, always transversely situated at the foreside of the body. Haplokinety (H) and polykinety (Po)complete one and one-half circuits on the peristome before entering the infundibulum, with a distal kinetal fragment pres-ent at the distal end. Silverline system consists of 37–45 pellicular striations between peristome and aboral trochal band(TB), and of 26–33 between TB and scopula. Colony is asymmetrically and dichotomously branched, usually with onlytwo levels of branches. In addition, the telotrochs of E. unioi were also observed and its structures were described herein.Besides, obvious skin lesions caused by the ringlike base of E. unioi were detected and the relationship between these epizooites and their hosts was briefly discussed as well.

Ontogeny and molecular phylogeny of a new marine ciliate genus, Heterokeronopsis g. n. (Protozoa, Ciliophora, Hypotricha), with description of a new species

The morphology and morphogenesis of a new ciliate, Heterokeronopsis pulchra g. n., sp. n., isolated from a mangrove wetland near Shenzhen, southern China, were investigated using live observation and protargol impregnation methods. Heterokeronopsis g. n. is characterized by having a bipartite adoral zone, an extremely shortened paroral membrane, frontal cirri arranged in an indistinct bicorona, a midventral complex composed of midventral pairs and midventral row(s), one left and one right marginal row, bipolar dorsal kineties, and buccal cirri; frontoterminal, transverse, and caudal cirri are absent. The single species H. pulchra sp. n. has a long, slender body that is brownish in colour, two kinds of cortical granules, one posteriorly located contractile vacuole, one buccal cirrus, usually six frontal cirri, three dorsal kineties, and one midventral row. The main morphogenetic features are: (i) the old oral apparatus is completely replaced by new structures derived from the oral primordium of the proter which originates de novo on the dorsal wall of the buccal cavity, (ii) the posteriormost frontal-midventral-transverse cirral anlage generates a midventral row, (iii) no frontoterminal and transverse cirri are formed, (iv) the anlagen for the marginal rows and the dorsal kineties are formed intrakinetally, and (v) the macronuclear nodules fuse into a mass at the middle stage. Phylogenetic analyses based on SSU rRNA gene sequence data reveal that Heterokeronopsis pulchra is a member of the family Pseudokeronopsidae and is most closely related to Nothoholosticha fasciola.

Effects of Roscovitine on Schedule of Divisional Morphogenesis, Basal Bodies Proliferation and Cell Divisions in Tetrahymena thermophila

During cell cycle of a ciliate Tetrahymena thermophila the divisions of micro- and macronucleus, cortical morphogenesis and cytokinesis are temporarily coordinated. Cortical morphogenesis begins with proliferation of the new ciliary basal bodies (BBs) within meridional cortical rows of ciliary BBs, and with the local proliferation of BBs, which form the new oral apparatus (OA2), positioned subequatorialy and destined for prospective posterior daughter cell (opisthe). Prior to cytokinesis, two prospective daughter cells are of equal size and show metamery of their cortical patterns. We studied effects of 20 μM roscovitine (an inhibitor of several cyclin-dependent kinases) on the cell cycle progression of T. thermophila. We showed that roscovitine delayed cell division, delayed or arrested macronuclear division and induced increase of cell size and the number of BBs in the cortical rows. The increase in the number of BBs in cortical rows induced cell elongation which was proportional to the increase in cell surface area. There was uncoupling between this BBs proliferation which is continued during prolonged cell cycle and delayed cytokinesis, what resulted in topological alteration of the respective positions of the OA2 and of the contractile vacuole pores (CVPs). In roscovitine treated cells, the new OA2 was positioned subequatorialy, but the fission zone was shifted posterior to the equatorial plane of the cell and positioned across and in the extreme cases behind of the new OA2. This resulted in the formation of a large proter and small size opisthe. The roscovitine treatment induced a formation of a plethora of phenotypes of postdividing cells. We found that irrespective of changes in divisional morphogenesis induced by roscovitine treatment, all mature BBs were associated with the cdc14-like phosphatase. Taken together all these data indicate that during cell cycle of T. thermophila the normal morphology of the daughter cells depends on the proper division of micro- and macronucleus and on temporal control of BBs proliferation along the longitudinal rows, during OA2 stomatogenesis and during selection of BBs involved in differentiation of apical BBs (couplets) and cell division.

Morphogenesis and morphology of Certesia quadrinucleata (Protozoa: Ciliophora) from Japan

The morphogenesis and morphology of the marine benthic ciliate Certesia quadrinucleata collected from seawater in Nagasaki Mie Port, Japan, were investigated using microscopic observation of live and protargol-stained specimens. In terms of its morphology, the current isolate possesses diagnostic features of the genus and the species: a row of left marginal cirri, a prominent paroral membrane, 11 frontoventral cirri scattered in frontoventral area, five highly developed transverse cirri, four macronuclear nodules, five dorsal kineties and a caudally located contractile vacuole. Its morphogenesis belongs to the ‘Certesia’ subtype, and main events can be summarized as follow: (1) the oral primordium in the opisthe develops de novo in a subcortical pouch; (2) the old paroral membrane is completely replaced by the new one in the proter, but the parental adoral zone of membranelles is wholly inherited; (3) five streaks of cirral anlagen are formed in a primary mode for the proter and the opisthe, which gives rise to cirri in the pattern of 3:3:3:3:3 from left to right; (4) the leftmost frontoventral cirrus develops de novo on the cell surface in both dividers, and has no connection with the undulating membrane anlage; and (5) the anlagen for marginal cirri and dorsal kineties occur intrakinetally. Current observations confirm the separation of Certesiidae from other euplotids at the familial level.

A redescription of the oxytrichid Tetmemena pustulata ( ) and notes on morphogenesis in the marine urostylid Metaurostylopsis salina Lei et al., 2005 (Ciliophora, Hypotrichia)

Two hypotrichous ciliates from China were investigated. The common oxytrichid species Tetmemena pustulata (Müller, 1786) Eigner, 1999, isolated from the estuary of the Pearl River in southern China, was investigated with emphasis on its living morphology and infraciliature. Tetmemena pustulata is characterized as follows: body elliptical to obovoid in shape; 75–115×40–60μm in vivo; two macronuclear nodules and two micronuclei; one contractile vacuole left of midline and somewhat ahead of midbody positioned; three frontal, four frontoventral, one buccal, three postoral ventral, two pretransverse ventral and five transverse cirri; cirrus III/2 ahead of level of cirrus IV/3; cirrus IV/2 arranged more anteriorly than cirrus V/4; transverse cirri not forming two distinct groups; three prolonged and widely separated caudal cirri; six dorsal kineties in Oxytricha-pattern with dorsal kineties 3 and 4 bipolar. The marine urostylid species Metaurostylopsis salina Li et al., 2005, isolated from an aquarium in Qingdao, northern China, was investigated with emphasis on its morphogenesis which is characterized by the de novo formation of the oral primordium in the proter and the development of the marginal rows from two anlagen that form within each parental structure separately in both dividers.

A Mechanism of Intracellular P2X Receptor Activation

P2X receptors (P2XRs) are ATP-activated calcium-permeable ligand-gated ion channels traditionally viewed as sensors of extracellular ATP during diverse physiological processes including pain, inflammation, and taste. However, in addition to a cell surface residency P2XRs also populate the membranes of intracellular compartments, including mammalian lysosomes, phagosomes, and the contractile vacuole (CV) of the amoeba Dictyostelium. The function of intracellular P2XRs is unclear and represents a major gap in our understanding of ATP signaling. Here, we exploit the genetic versatility of Dictyostelium to investigate the effects of physiological concentrations of ATP on calcium signaling in isolated CVs. Within the CV, an acidic calcium store, P2XRs are orientated to sense luminal ATP. Application of ATP to isolated vacuoles leads to luminal translocation of ATP and release of calcium. Mechanisms of luminal ATP translocation and ATP-evoked calcium release share common pharmacology, suggesting that they are linked processes. The ability of ATP to mobilize stored calcium is reduced in vacuoles isolated from P2X(A)R knock-out amoeba and ablated in cells devoid of P2XRs. Pharmacological inhibition of luminal ATP translocation or depletion of CV calcium attenuates CV function in vivo, manifesting as a loss of regulatory cell volume decrease following osmotic swelling. We propose that intracellular P2XRs regulate vacuole activity by acting as calcium release channels, activated by translocation of ATP into the vacuole lumen.

New Records of Two Stichotrichid Ciliates, Afroamphisiella multinucleata and Pseudokahliella marina (Ciliophora: Spirotrichea: Stichotrichida) from Korea

Two stichotrichid ciliates, collected from marine waters in Jeju Island, were identified as Afroamphisiella multinucleata Foissner et al., 2002 and Pseudokahliella marina (Foissner et al., 1982) Berger et al., 1985. They are recorded for the first time in Korea. The descriptions are based on examinations of living as well as protargol-impregnated specimens. These species are characterized as follows. Afroamphisiella multinucleata has a body size in vivo of <TEX>$70-95{\times}20-35{\mu}m$</TEX>; elongate rectangular in shape; contractile vacuole located slightly above mid-body. The adoral zone is bipartited into 3 distal and 13-17 proximal membranelles and occupies 28-35% of the body length. The frontal row comprises 1-4 cirri and one buccal cirrus. The amphisiellid median cirral row is composed of 14-21 cirri, 10-19 left marginal cirri, and 21-30 right marginal cirri. Cortical granules are yellowish. 11-20 globular/ellipsoidal macronuclear nodules arrange proximally along the cell margins. Pseudokahliella marina has a body size in vivo of <TEX>$110-195{\times}40-110{\mu}m$</TEX> and broadly elliptical in shape. The adoral zone of the membranelles occupies 50-60% of the body length, and is composed of 41-70 membranelles. A prominent frontal scutum is present. The contractile vacuole is located below the mid-body. There are 11-13 frontoventral rows, including marginal rows. Caudal cirri and transverse cirri are absent. Three invariable non-fragmented bipolar dorsal kineties are present. The left and right marginal rows are composed of 22-35 and 28-40 cirri, respectively. Colourless cortical granules are present. 8-11 spherical/ellipsoidal macronuclear nodules are connected with each other by thread-like tructures, forming an inverted C-shape.

Morphological and Molecular Characterization of Paramecium (Viridoparamecium nov. subgen.) chlorelligerum Kahl (Ciliophora)

We redescribe Paramecium chlorelligerum, a forgotten species, which Kahl (Tierwelt Dtl., 1935, 30:651) briefly but precisely described in the addendum to his ciliate monographs as a Paramecium with symbiotic green algae. The redescription is based on classical morphological methods and the analysis of the small subunit (SSU) rDNA. Morphologically, P. chlorelligerum differs from P. (C.) bursaria, the second green species in the genus, by having a special swimming shape, the length of the caudal cilia, the size of the micronucleus, the size of the symbiotic algae, the contractile vacuoles (with collecting vesicles vs. collecting canals), and the number of excretory pores/contractile vacuole (1 vs. 2-3). The molecular investigations show that P. chlorelligerum forms a distinct branch distant from the P. (Chloroparamecium) bursaria clade. Thus, we classify P. chlorelligerum in a new subgenus: Paramecium (Viridoparamecium) chlorelligerum. The symbiotic alga belongs to the little-known genus Meyerella, as yet recorded only from the plankton of a North American lake.

Morphology of three new marine Frontonia species (Ciliophora; Peniculida) with note on the phylogeny of this genus

Members of the ciliate genus Frontonia are common colonizers of periphytic communities in aquatic biotopes. Recent studies indicate that their species diversity is higher than previously supposed. In this study the morphology and infraciliature of three new species, Frontonia sinica spec. nov., F. pusilla spec. nov., and F. elegans spec. nov., isolated from coastal waters of China, were investigated using live observation and silver impregnation methods. Frontonia sinica differs from its congeners by the following combination of characters: ellipsoidal body, about 116 somatic and five or six vestibular kineties, peniculi 1 and 2 four-rowed, peniculus 3 two-rowed, and a single contractile vacuole. Frontonia pusilla has about 72 somatic kineties, four-rowed peniculi 1 and 2, a two-rowed peniculus 3, and two contractile vacuoles. Frontonia elegans has 73 somatic kineties, four-rowed peniculi 1 and 2, a three-rowed peniculus 3, and two contractile vacuoles. In the present work, six new small-subunit rRNA gene sequences of six Frontonia species are used to construct the phylogenetic trees. Our phylogenetic analysis supports that the genus Frontonia may be paraphyletic. Meanwhile, no pattern of correlation could be found between the structures of peniculi and the phylogenetic relationships of Frontonia species in the present study.

Morphology and SSU rRNA gene sequences of three Frontonia species, including a description of F. subtropica spec. nov. (Ciliophora, Peniculida)

The morphology and infraciliature of three Frontonia species, F. subtropica spec. nov., F. canadensis Roque and Puytorac, 1972, and F. magna Fan et al., 2011, isolated from coastal waters in southern China sea, were investigated using living observation and silver impregnation methods. Frontonia subtropica spec. nov. is recognized by the combination of the following characters: body elliptical in outline with right margin depressed in anterior third, about 180–230μm×60–80μm in vivo; 104–114 somatic kineties; peniculi 1–3 each with four kineties; five vestibular and five postoral kineties; one centrally located elongate-elliptical macronucleus; single contractile vacuole located left-dorsally in posterior third of body. We also provide improved diagnoses for F. canadensis and F. magna based on current and previous reports. The small subunit (SSU) rRNA gene was sequenced for all three species. Comparisons with sequences of morphologically similar congeners clearly support the validity each species.

Rigifila ramosa n. gen., n. sp., a Filose Apusozoan with a Distinctive Pellicle, is Related to Micronuclearia

We report the ultrastructure, 18S and 28S rDNA sequences, and phylogenetic position of a distinctive free-living heterotrophic filose protist, Rigifila ramosa n. gen., n. sp., from a freshwater paddyfield. Rigifila lacks cilia and has a semi-rigid, radially symmetric, well-rounded, partially microtubule-supported, dorsal pellicle, and flat mitochodrial cristae. From a central aperture in a ventral depression emerges a protoplasmic stem that branches into several branching filopodia that draw bacteria to it. Electron microscopy reveals a general cell structure similar to Micronuclearia, the only non-flagellate previously known in Apusozoa; the large basal vacuole is probably an unusual giant contractile vacuole. Phylogenetic analysis of concatenated rDNA sequences groups Rigifila and Micronuclearia as sisters with maximal statistical support. However, novel morphological differences unique to Rigifila, notably a double (not single) proteinaceous layer beneath the cell membrane, and cortical microtubules, lead us to place it in a new family Rigifilidae. Our morphological and molecular analyses show that Rigifila is the closest known relative of Micronuclearia. Therefore we group Micronucleariidae and Rigifilidae as a new order Rigifilida within the existing class Hilomonadea, which now excludes planomonads. Rigifilida groups weakly with Collodictyon (Diphyllatea). We discuss the possible relationships of Rigifilida to other Apusozoa and Diphyllatea.

Morphology, morphogenesis, and molecular phylogeny of a new brackish water ciliate, Pseudourostyla cristatoides n. sp., from Songjiho lagoon on the coast of East Sea, South Korea

A new brackish water urostylid ciliate, Pseudourostyla cristatoides n. sp. was collected from Songjiho lagoon on the coast ofEast Sea, South Korea, and investigated based on morphology, morphogenesis, and 18S rRNA gene sequences.Pseudourostyla cristatoides is characterized by the following features: slender to elliptical body shape; colourless to dark greyin colour; size in vivo about 220–265 × 85–125μm; flexible and slightly contractile body with narrowly spaced extrusomes(trichocyst type) throughout the whole cell; 2 contractile vacuoles on left side of cell at about 25% and 75% of body length;84–115 adoral membranelles, 20–30 frontal cirri, 1 buccal cirrus, 2 frontoterminal cirri, 17–25 midventral pairs, 2pretransverse, 6–12 transverse cirri, 5–7 left and 4–5 right marginal rows, and 10–13 dorsal kineties; 30–106 macronuclearnodules and 3–5 micronuclei; brackish habitat (salinity 3–5‰). This new species is very similar to P. cristata, but distinguishedprimarily by contractile vacuoles (2 vs. 1 in number; positioned 25%, 75% of body length vs. ahead of mid-body), dorsalkineties (10–13 vs. 8), hyaline layer underneath pellicle (inconspicuous vs. conspicuous), habitat (brackish vs. freshwater), andparticipation of posterior cirri of rear corona in fronto-ventral-transverse cirral anlagen (yes vs. no). Additionally, intra-/inter-specific pairwise genetic distances of the 18S rRNA gene sequences supported that the Songjiho population is a novel species(intra-specific distances of 0.07–0.12% among three P. cristata populations vs. inter-specific distances of 0.93–1.00% between P. cristatoides and three P. cristata populations).

Taxonomic Revision and Neotypification of Zosterodasys transversus (Kahl, 1928), with Description of a Mirror-Image Doublet (Ciliophora, Phyllopharyngea, Synhymeniida)

The present work describes the morphology and morphometry of a freshwater ciliate, Zosterodasys transversus, using live observation and protargol impregnation. The population from the River Ipeľ, Slovakia is designated as a neotype because (i) no type material is available from the species described by Kahl (1928); (ii) the neotype is consistent with Z. transversus as described by Kahl (1928); (iii) the neotype is from the same biogeographic region as Kahl’s (1928) populations; and (iv) there are several similar species (e.g., Z. agamalievi) whose identity is threatened by the species to be neotypified. The main features of Z. transversus are: (i) a body size of 120–240 × 50–115 μm in vivo; (ii) a broadly to narrowly obovate or elliptical body; (iii) a spherical to very narrowly ellipsoidal macronucleus with a single globular micronucleus nearby; (iv) several scattered contractile vacuoles; (v) an average of 82 ciliary rows, most of which are interrupted by a synhymenium incompletely encircling the body; and (vi) an average of 14 nematodesmal rods strengthening walls of the cyrtos. In the well-growing neotype population, a single cell of a mirror-image type was found. Most of the structures of this monster specimen are similar to those from ordinary cells, except for the double cytostome and cyrtos.

Functional characterization of mitofusin‐like protein from Dictyostelium discoideum

The balance between mitochondrial fission and fusion maintains mitochondrial morphology and function. In mammals, three large GTPases ‐ Opa1 and the mitofusins Mfn1 and Mfn2 ‐ are required for the fusion of inner and outer mitochondrial membranes. The Dictyostelium mitofusin MfnA GTPase domain shares only 24% identity with the corresponding region of human Mfn1 and lacks a typical Fzo‐mitofusin family region. To define the cellular function of the Dictyostelium protein, we used molecular genetic approaches to manipulate the production level of MfnA and to follow the localization of the fluorophore‐tagged protein. In cells producing MfnA with a C‐terminal eYFP‐tag, the protein is targeted to the outer mitochondrial membrane. Overproduction of wild type MfnA and GTPase deficient mutants K132A or S133N leads to peri‐nuclear mitochondrial clustering and the phenotype is not due to any cytoskeletal defect. Unlike mammalian Mfn1/2, both N‐terminal and C‐terminal MfnA domains are required for mitochondrial targeting. N‐terminal deleted construct shows partial co‐localization with the ER, while double deletion of N‐terminal and transmembrane domain induces association with plasma membrane and contractile vacuoles. MfnA null cells have fewer and more dispersed mitochondria but appear otherwise normal. Thus our results reveal that MfnA alters mitochondrial morphology by fusing outer mitochondrial membranes.

Rab8a regulates the exocyst-mediated kiss-and-run discharge of theDictyosteliumcontractile vacuole

Water expulsion by the contractile vacuole (CV) in Dictyostelium is carried out by a giant kiss-and-run focal exocytic event during which the two membranes are only transiently connected but do not completely merge. We present a molecular dissection of the GTPase Rab8a and the exocyst complex in tethering of the contractile vacuole to the plasma membrane, fusion, and final detachment. Right before discharge, the contractile vacuole bladder sequentially recruits Drainin, a Rab11a effector, Rab8a, the exocyst complex, and LvsA, a protein of the Chédiak-Higashi family. Rab8a recruitment precedes the nucleotide-dependent arrival of the exocyst to the bladder by a few seconds. A dominant-negative mutant of Rab8a strongly binds to the exocyst and prevents recruitment to the bladder, suggesting that a Rab8a guanine nucleotide exchange factor activity is associated with the complex. Absence of Drainin leads to overtethering and blocks fusion, whereas expression of constitutively active Rab8a allows fusion but blocks vacuole detachment from the plasma membrane, inducing complete fragmentation of tethered vacuoles. An indistinguishable phenotype is generated in cells lacking LvsA, implicating this protein in postfusion detethering. Of interest, overexpression of a constitutively active Rab8a mutant reverses the lvsA-null CV phenotype.

Redescription of Two Urostylid Ciliates (Ciliophora: Urostylida), Anteholosticha pulchra and Metaurostylopsis struederkypkeae from Korea

Two urostylid ciliates, Anteholosticha pulchra (Kahl, 1932) Berger, 2003 and Metaurostylopsis struederkypkeae Shao et al., 2008, new to Korea, were collected from the Yellow Sea and the East Sea, Korea, respectively. They were identified based on live observation and protargol impregnation. Taxonomical characters of A. pulchra are as follows: <TEX>$190-300{\times}30-55\;{\mu}m$</TEX> size in vivo; contractile vacuole located on the left side of the posterior 1/4 of the cell; spherical-reddish granules at cirral bases and around dorsal bristles, somewhat sparsely distributed throughout the cell surface; four frontal and two frontoterminal cirri; four dorsal kineties; caudal cirri absent. Metaurostylopsis struederkypkeae is characterized as follows: <TEX>$80-110{\times}40-50\;{\mu}m$</TEX> size in vivo; caudal cirri absent; two types of cortical granules: type 1, yellow-green arranged along the ventral cirral rows and dorsal kineties; type 2, small and reddish, with an irregular arrangement; four frontal, four to eight frontoterminal, and two to six transverse cirri; five to seven left and three to five right marginal rows. Sequences of small subunit ribosomal DNA were determined from both species, and pairwise distances with their relatives were analyzed.

Resdescription of two synhymeniid ciliates, Chilodontopsis simplex Ozaki &amp;amp; Yagiu, 1941 and Zosterodasys transverses (Kahl, 1928) Foissner et al., 1994 (Alveolata, Ciliophora, Phyllopharyngea)

The morphology and infraciliature of two synhymeniid ciliates, Chilodontopsis simplex Ozaki &amp; Yagiu, 1941 and Zoster-odasys transverses (Kahl, 1928) Foissner et al., 1994, collected from coasts of Qingdao, China, and Incheon, South Korea,respectively, have been investigated using live observation and protargol impregnation method. Chilodontopsis. simplexis characterized by: cell size 90–160 × 45–95 µm in vivo, oval to long elliptical in outline; 59–78 somatic kineties, 11–13nematodesmal rods; synhymenium constricted to ventral side, composed of 45–90 dikinetids, running across cell width;single contractile vacuole located in posterior cell end. The marine population of Zosterodasys transverses is briefly de-scribed, linked to the previously reported 18S ribosomal RNA gene (Genbank accession number EU286812), and compared to the freshwater population.

Exuviotrophic apostome ciliates from freshwater decapods in southern Alabama (USA) and a description of Hyalophysa clampi n. sp. (Ciliophora, Apostomatida)

Apostome ciliates from crayfish and freshwater shrimp in southern and central Alabama were surveyed in this study. Hyalophysa bradburyae was found on both crayfish and shrimp from 16 sites in eight drainages. A new species, Hyalophysa clampi n. sp., was found infesting crayfish at one site and simultaneously infesting crayfish with H. bradburyae at two sites. Characteristics of the trophont ciliature of H. clampi n. sp. separate it from other species in the genus. Particularly, the contractile vacuole pore is oriented posterior to the ventral kineties xyz, kineties 1 and 2 are undivided, an apparent second contractile vacuole pore is present between the ventral portions of kineties 1 and 2, the anterior ventral field is tightly arranged, and there is an apical field of kineties between kineties 4 through 6. This report expands the known range and diversity of the genus Hyalophysa in the state of Alabama.