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Triadinium was created to include Triadinium caudatum. Further, four other species were included, T. minimum, T. galea, T. elongatum, and T. magnum, all sharing a characteristic helmet-shaped body. Wolska and Grain argued that the inclusion of T. minimum and T. galea into Triadinium was done based on superficial morphological aspects, and established two new genera to accommodate these species: Circodinium and Gassovskiella. Although the phylogenetic relationships within Entodiniomorphida have been investigated by multiple authors, none of them discussed the evolutionary relationship of helmet-shaped entodiniomorphids. We performed molecular phylogenetics and revisited old literature digging for morphological data to explain our results. According to our analyses, the helmet-shaped body is homoplastic and may have evolved from at least three different entodiniomorphid ancestors. Circodinium minimum is phylogenetically related to members of Blepharocorythidae, T. caudatum emerged within Spirodiniidae and G. galea within Polydiniellidae. This phylogenetic hypothesis is partially supported by information on infraciliature and ultrastructure of C. minimum and T. caudatum. However, such morphological information is not available for polydiniellids. In order to shed some light into the evolution of the helmet-shaped ciliates, future works should focus to collect information on the infraciliature and the ultrastructure of Polydiniella mysorea and of other Triadinium species.

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Abstract The morphological variability of Eodinium posterovesiculatum (Ciliophora, Trichostomatia) has been interpreted in different ways: four distinct species or four morphotypes of the same species. The present study aims to perform morphological and morphometric comparative analysis of the four morphotypes found in cattle from the southeastern region of Brazil. Ruminal content samples were obtained from four Holstein x Gir cattle and fixed at 18.5% formalin for morphological analysis. Morphometry was performed based on individuals stained with Lugol's solution [1]. The infraciliary bands were stained using silver carbonate impregnation technique [2]. Morphological and morphometric characterizations, supported by literature, suggest that the four morphotypes of E. posterovesiculatum are actually a single polymorphic species due to small morphometric differences and mostly identical morphological characters, with the format of the caudal processes being the only morphological characteristic that sets them apart.

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A new oligotrich similar to Novistrombidium was discovered in plankton samples from an artificial tributary of the Salado River, Buenos Aires province, Argentina, in summer 2010. Propecingulum fistoleramalliei sp. n. has an obovate and anteriorly truncated body, with a conspicuous ventral furrow, is flattened ventrally, and has a prominent right apical protrusion. It temporarily attaches to the substratum by a posterior mucous thread. Rod-shaped extrusomes arranged equidistantly and insert directly above the girdle kinety. The macronucleus is globular to ellipsoidal. The contractile vacuole is located in the left, anterior quarter of the cell and the adoral zone is composed of 30-35 collar, 9-14 buccal, and two thigmotactic membranelles. The girdle kinety is dextrally spiraled and ventrally open; the ventral kinety is posterior to anterior end of the girdle kinety. The oral primordium develops posterior to the right thigmotactic membranelle and anterior the stripe of extrusomes above left, lateral portion of the girdle kinety. The SSUrDNA phylogeny confirms one more time that Novistrombidium is not monophyletic; consequently, we elevate the subgenus Propecingulum up to genus rank and redefine the genus Novistrombidium.

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Short-period variability in plankton communities is poorly documented, especially for variations occurring in specific groups in the assemblage because traditional analysis is laborious and time-consuming. Moreover, it does not allow the high sampling frequency required for decision making. To overcome this limitation, we tested the submersible CytoSub flow cytometer. This device was anchored at a distance of approximately 10 metres from the low tide line at a depth of 1.5 metres for 12 hours to monitor the plankton at a site in the biological reserve of Barra da Tijuca beach, Rio de Janeiro. Data analysis was performed with two-dimensional scatter plots, individual pulse shapes and micro images acquisition. High-frequency monitoring results of two interesting groups are shown. The abundance and carbon biomass of ciliates were relatively stable, whereas those from dinoflagellates were highly variable along the day. The linear regression of biovolume measures between classical microscopy and in situ flow cytometry demonstrate high degree of adjustment. Despite the success of the trial and the promising results obtained, the large volume of images generated by the method also creates a need to develop pattern recognition models for automatic classification of in situ cytometric images.(AU)

A variabilidade de curto período em comunidades do plâncton é pouco documentada, especialmente as variações que ocorrem em grupos específicos das assembleias por causa das análises tradicionais serem muito trabalhosas e demoradas. Além disso, não permitem que a alta frequência amostral necessária para a tomada de decisão. Para superar esta limitação, nós testamos o CytoSub, um citômetro de fluxo submersível. Este aparelho foi ancorado a aproximadamente 10 metros de distância da linha de maré baixa a uma profundidade de 1,5 metros por 12 horas para monitorar o plâncton em um sítio da reserva biológica da praia da Barra da Tijuca, Rio de Janeiro. A análise dos dados foi realizada a partir de gráficos de dispersão bidimensionais, pelas assinaturas ópticas individuais escaneadas (pulse shape profile) e aquisição de micro imagens. Resultados do monitoramento de alta frequência de dois grupos interessantes são apresentados. A abundância e a biomassa de carbono de um grupo de ciliados foram relativamente estáveis, ao passo que o grupo de dinoflagelado, foi altamente variável ao longo do dia. O modelo de regressão linear das medidas de biovolume entre a clássica microscopia e a citometria de fluxo in situ apresentou alto grau de ajustamento. Apesar do sucesso deste ensaio e dos resultados promissores obtidos, o grande volume de imagens geradas por este método também gerou a necessidade de se desenvolver modelos de reconhecimento de padrões para a classificação automática de imagens de citometria in situ.(AU)

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Ciliates of the genus Gruberia are poorly studied. Consequently, most species lack detailed morphological descriptions, and all gene sequences in GenBank are not classified at the species level. In this study, a detailed morphological description of a population of G. lanceolata from Brazil is presented, based on live and protargol-stained organisms. We also present the 18S rRNA gene sequence and the phylogenetic position of this species. The primary characteristics of G. lanceolata from the Maricá Lagoon are as follows: an elongate fusiform body 280-870 × 40-160 µm in size; rosy cortical granules; a peristome occupying approximately 1/3-1/2 of body length; an adoral zone comprising 115-330 membranelles; a paroral membrane in 35-50 fragments; and a moniliform macronucleus with 11-16 nodules. Based on our observations and data from pertinent literature, we suggest G. beninensis to be a junior synonym of G. lanceolata.

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Abstract Short-period variability in plankton communities is poorly documented, especially for variations occurring in specific groups in the assemblage because traditional analysis is laborious and time-consuming. Moreover, it does not allow the high sampling frequency required for decision making. To overcome this limitation, we tested the submersible CytoSub flow cytometer. This device was anchored at a distance of approximately 10 metres from the low tide line at a depth of 1.5 metres for 12 hours to monitor the plankton at a site in the biological reserve of Barra da Tijuca beach, Rio de Janeiro. Data analysis was performed with two-dimensional scatter plots, individual pulse shapes and micro images acquisition. High-frequency monitoring results of two interesting groups are shown. The abundance and carbon biomass of ciliates were relatively stable, whereas those from dinoflagellates were highly variable along the day. The linear regression of biovolume measures between classical microscopy and in situ flow cytometry demonstrate high degree of adjustment. Despite the success of the trial and the promising results obtained, the large volume of images generated by the method also creates a need to develop pattern recognition models for automatic classification of in situ cytometric images.

Resumo A variabilidade de curto período em comunidades do plâncton é pouco documentada, especialmente as variações que ocorrem em grupos específicos das assembleias por causa das análises tradicionais serem muito trabalhosas e demoradas. Além disso, não permitem que a alta frequência amostral necessária para a tomada de decisão. Para superar esta limitação, nós testamos o CytoSub, um citômetro de fluxo submersível. Este aparelho foi ancorado a aproximadamente 10 metros de distância da linha de maré baixa a uma profundidade de 1,5 metros por 12 horas para monitorar o plâncton em um sítio da reserva biológica da praia da Barra da Tijuca, Rio de Janeiro. A análise dos dados foi realizada a partir de gráficos de dispersão bidimensionais, pelas assinaturas ópticas individuais escaneadas (pulse shape profile) e aquisição de micro imagens. Resultados do monitoramento de alta frequência de dois grupos interessantes são apresentados. A abundância e a biomassa de carbono de um grupo de ciliados foram relativamente estáveis, ao passo que o grupo de dinoflagelado, foi altamente variável ao longo do dia. O modelo de regressão linear das medidas de biovolume entre a clássica microscopia e a citometria de fluxo in situ apresentou alto grau de ajustamento. Apesar do sucesso deste ensaio e dos resultados promissores obtidos, o grande volume de imagens geradas por este método também gerou a necessidade de se desenvolver modelos de reconhecimento de padrões para a classificação automática de imagens de citometria in situ.

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RESUMO

Short-period variability in plankton communities is poorly documented, especially for variations occurring in specific groups in the assemblage because traditional analysis is laborious and time-consuming. Moreover, it does not allow the high sampling frequency required for decision making. To overcome this limitation, we tested the submersible CytoSub flow cytometer. This device was anchored at a distance of approximately 10 metres from the low tide line at a depth of 1.5 metres for 12 hours to monitor the plankton at a site in the biological reserve of Barra da Tijuca beach, Rio de Janeiro. Data analysis was performed with two-dimensional scatter plots, individual pulse shapes and micro images acquisition. High-frequency monitoring results of two interesting groups are shown. The abundance and carbon biomass of ciliates were relatively stable, whereas those from dinoflagellates were highly variable along the day. The linear regression of biovolume measures between classical microscopy and in situ flow cytometry demonstrate high degree of adjustment. Despite the success of the trial and the promising results obtained, the large volume of images generated by the method also creates a need to develop pattern recognition models for automatic classification of in situ cytometric images.

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The validity of genus Eodinium has been historically disputed due to morphological similarities with Diplodinium (absence of skeletal plates as well as adoral and dorsal ciliary zones at the same body level). To address this issue, the 18S rDNA of four Eodinium posterovesiculatum morphotypes and four Diplodinium anisacanthum morphotypes were sequenced and phylogenetically analyzed. The different inference methods suggest the existence of a last common ancestor of Eodinium and Ostracodinium that is not shared with Diplodinium, strongly supporting the validity of genus Eodinium. Since skeletal plates are present in all members of genus Ostracodinium, the most parsimonious is a secondary loss of skeletal plates in E. posterovesiculatum. This work represents a breakthrough in the taxonomy and phylogeny of the family Ophryoscolecidae indicating that the skeletal plates may not reflect evolutionary divergence within this group of ciliates as traditionally proposed.

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The aims of the present study were (1) to evaluate the abundance and taxonomic composition of ciliated protozoa in the activated sludge of a full-scale combined anaerobic-aerobic system operating in a tropical country and (2) to study the relationship between the effluent quality, the physicochemical variables, and the ciliates present in the operating system. The total ciliate fauna of the activated sludge of the Piçarrão Wastewater Treatment Plant (Piçarrão WWTP) was composed of 36 morphospecies belonging to 33 genera. These included 21 species observed in the activated sludge samples on the day of collection and 15 species found in cultures. The activated sludge of the Piçarrão WWTP contained a diversified ciliate community composed mainly of indicator organisms. The most frequently occurring morphospecies were Aspidisca cicada, Vorticella spp., Gastronauta aloisi, Acineria uncinata, and Epistylis plicatilis complex. These results showed that satisfactory operating conditions prevailed at the Piçarrão WWTP. In the combined UASB-activated sludge system, the presence of Aspidisca cicada suggests the occurrence of denitrification in the process while the presence of Acineria uncinata and G. alosi indicates the removal of carbonaceous organic matter.

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Morphology and divisional morphogenesis of the hypotrich ciliate Apoamphisiella vernalis are investigated based on two populations from Brazil. Typical specimens of A. vernalis replicates its ventral ciliature from six fronto-ventral-transverse (FVT) anlagen independently formed for proter and opisthe, plus one or more short anlagen located between IV and V, which form surplus transverse cirri. Dorsal morphogenesis occurs as in typical oxytrichid dorsomarginalians, viz., with formation of three anlagen and fragmentation of the rightmost one. Dorsomarginal kineties are formed near anterior end of right marginal cirral row anlagen. Various anomalous specimens exhibiting more than two long ventral rows were found, which are explained by increasing the number of FVT anlagen and/or the number of cirri produced by anlagen. Comparative ontogeny and phylogenetic analyses based on the 18S rDNA reveal that Apoamphisiella vernalis is closely affine to North American and European strains of the Paraurostyla weissei complex. Their reduced genetic distances and conspicuous morphological variability show that both genera can overlap, which implies the necessity of re-evaluating the contextual relevance of some morphological characters commonly used for genus-level separation within hypotrich taxa.

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Interphase specimens, aspects of physiological reorganization and divisional morphogenesis were investigated in a strain of a hypotrichous ciliate highly similar to Urostyla grandis Ehrenberg, (type species of Urostyla), collected from a mangrove area in the estuary of the Paraíba do Sul river (Rio de Janeiro, Brazil). The results revealed that albeit interphase specimens match with the known morphologic variability in U. grandis, morphogenetic processes have conspicuous differences. Parental adoral zone is entirely renewed during morphogenesis, and marginal cirri exhibit a unique combination of developmental modes, in which left marginal rows originate from multiple anlagen arising from innermost left marginal cirral row, whereas right marginal ciliature originates from individual within-row anlagen. Based on such characteristics, a new subspecies, namely U. grandis wiackowskii subsp. nov. is proposed, and consequently, U. grandis grandis Ehrenberg, stat. nov. is established. Bayesian and maximum-likelihood analyses of the 18S rDNA unambiguously placed U. grandis wiackowskii as adelphotaxon of a cluster formed by other U. grandis sequences. The implications of such findings to the systematics of Urostyla are discussed.

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Corlissina maricaensis gen. nov., sp. nov. was obtained from samples of sediment collected in a brackish lagoon of Maricá city, Rio de Janeiro state, Brazil. The morphological description was based on live observations, after protargol staining, and scanning electron microscopy. The novel species has a cylindrical body shape that is slightly contractile, 230-550 × 35-65 µm, a cytoplasm with many globular inclusions, one row of irregular cortical granules between each somatic kinety, approximately 40-62 somatic kineties, two globular macronuclei measuring 9-24 µm and one micronucleus of approximately 4-9 µm. A subapical oral cavity was approximately 20-80 × 9-25 µm, with an adoral zone on the left side of the buccal field, which was composed of 32-60 polykineties and a paroral at the right side that was composed of 40-57 short polykineties. The new genus is distinguished from other geleiids by a loop-shaped posterior end of the paroral ciliature, made up of two rows of short polykineties, and the oralization of the central superior kinety (K0i), forming a row of dikinetids that borders the adoral zone internally, followed by several rows of monokinetids. In the phylogenetic analyses, the novel species was recovered as the sister group of Parduczia orbis with full support values based on 18S rRNA gene sequences. This work also indicates some problems in the definitions of the Geleiidae and proposes a new diagnosis for this karyorelictid family.

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Details on Condylostoma arenarium infraciliature have not been described; therefore, it is considered a poorly known species. The lack of detailed description on C. arenarium morphology caused several misidentifications that have accumulated in the literature. In this study, we present the first complete description of C. arenarium infraciliature based on protargol-impregnated organisms and scanning electron microscopy. We also have inferred the phylogenetic position of this species based on 18S rRNA sequences. The main characteristics of C. arenarium population from Guanabara Bay are as follows: in vivo elongated body shape with 350-600 µm length × 70-220 µm width, they are highly contractile when subjected to disturbances, green-yellowish cortical granules are present, contractile vacuoles absent, V-shaped peristome comprises approximately 1/5 of the total length, adoral zone with 83-145 membranelles, 1-2 small frontal cirrus observed only in impregnated specimens, 10-15 fiber-like stripes arranged transversely on the inner wall of the oral cavity, 30-45 somatic kineties, moniliform macronucleus with 15-20 nodules. Some observations on morphogenesis of C. arenarium were also included. In phylogenetic analyses, C. arenarium clustered with Condylostoma sp. within a clade composed of three C. curva sequences with high support values.

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Using standard methods, we studied the morphology and distribution of an Australian population of Australocirrus shii (Shi et al., 1997) nov. comb. and a Jamaican population of A. australis (Foissner, 1995) nov. comb. We identified three features, not or rarely used earlier, that distinguish Australocirrus shii from A. australis: the distance between the anterior pretransverse cirrus and the anteriormost transverse cirrus (5-8% vs. 1.5-1.7% of body length), the arrangement of the transverse cirri (3+2 vs. an oblique row), and the resting cyst macronuclear nodules (separate vs. fused). Australocirrus shii has been reported from Asia and Australia while A. australis is possibly restricted to the Neotropic. Because of problems in getting voucher materials of A. shii, we emphasise that permanent slides should be deposited in international repositories. Based on previous studies and new data, especially a refined interpretation of the shape of the paroral membrane, we suggest synonymy of Cyrtohymenides and Australocirrus. Thus, Cyrtohymena (Cyrtohymenides) shii, C. (Cyrtohymenides) aspoecki, and C. (Cyrtohymenides) australis are transferred to Australocirrus which is, inter alia, defined by a moderately to distinctly curved, but not recurved, paroral membrane, multiple fragmentation of dorsal kinety 3 and three or more dorsomarginal kineties.

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Apoamphisiella Foissner, 1997 is a genus of hypotrichous ciliates reported to occur in various locations in the world, but that seems particularly widespread in the Americas. In this study, the first record of Apoamphisiella vernalis for Brazil is presented based on a population from the Atlantic Forest of the Minas Gerais state. A redescription of A. vernalis made from light and scanning electron microscopy observations unveils a unique combination of diagnostic features for this species, namely the presence of green cortical granules, one contractile vacuole lacking collecting canals, and the rear end of both left and right marginal cirral rows located at same level. Moreover, A. vernalis is found to be an omnivorous predator, feeding on arcelline testate amoebae, rotifers, and other organisms.

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Ciliates occur in all major aquatic and soil environments worldwide and are important links in the microbial food webs, which, along with other free-living protists, are generally overlooked in biodiversity conservation programs. In Brazil, the northern region comprises the Brazilian Amazonia, an area widely known for its huge biodiversity. However, the diversity of ciliates in that region is still almost unknown. As result of the present study, a total of 21 species of ciliates, distributed among 15 genera, were inventoried from samples of eutrophized water collected in the city of Belém, capital of the state of Pará, one of the states which comprise the Brazilian Amazonia. In addition, a local population of the rare scuticociliate Cristigera hammeri is described from optical and electron microscopy observations, and its synonymy with C. pleuronemoides is rejected based on new evidence.

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We investigated the live morphology, infraciliature, and small subunit rRNA gene sequences of an unusual population of Stentor polymorphus without symbiotic algae that was isolated from the southeastern region of Brazil. The morphological and molecular data confirmed the identity of this strain as S. polymorphus. The Brazilian S. polymorphus organism is 850-2,000 µm in length in vivo and has colorless cortical granules, a moniliform macronucleus with 6-12 nodules, somatic ciliature composed of 50-60 kineties, a single contractile vacuole located to the left of the cytostome, and a conspicuous oral pouch, and it does not build a lorica. Based on the phylogenetic analyses, the Brazilian S. polymorphus was located within a cluster consisting of four other S. polymorphus sequences, with high support values using both the Bayesian inference and maximum likelihood algorithms. Our study presents the first report of a S. polymorphus population without its symbionts under natural conditions. On the basis of our findings, we propose that the presence or absence of symbiotic algae should not be used as a taxonomic character for the identification of Stentor species.

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We have earlier shown that the typical Didinium nasutum nucleolus is a complex convoluted branched domain, comprising a dense fibrillar component located at the periphery of the nucleolus and a granular component located in the central part. Here our main interest was to study quantitatively the spatial distribution of nucleolar chromatin structures in these convoluted nucleoli. There are no "classical" fibrillar centers in D.nasutum nucleoli. The spatial distribution of nucleolar chromatin bodies, which play the role of nucleolar organizers in the macronucleus of D.nasutum, was studied using 3D reconstructions based on serial ultrathin sections. The relative number of nucleolar chromatin bodies was determined in macronuclei of recently fed, starved D.nasutum cells and in resting cysts. This parameter is shown to correlate with the activity of the nucleolus. However, the relative number of nucleolar chromatin bodies in different regions of the same convoluted nucleolus is approximately the same. This finding suggests equal activity in different parts of the nucleolar domain and indicates the existence of some molecular mechanism enabling it to synchronize this activity in D. nasutum nucleoli. Our data show that D. nasutum nucleoli display bipartite structure. All nucleolar chromatin bodies are shown to be located outside of nucleoli, at the periphery of the fibrillar component.

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Trichodinids are ciliated protozoa that are widely known as one of the main groups of fish parasites. The genus Trichodina presents the greatest species diversity. However, records of Paratrichodina species are scarce, and little is known about their pathogenicity in hosts. The present study provides new records of Paratrichodina africana Kazubski and El-Tantawy (1986) in Nile tilapia from South America and descriptions of pathological changes and seasonality. A total of 304 farmed fish were examined. From gill scraping, parasites were identified using Klein's nitrate impregnation method. Gill samples were fixed for histopathological analysis. Small trichodinid found in this study have a prominent blade apophysis and narrow central part and blade shape that corresponds to the characteristics of P. africana Kazubski and El-Tantawy (1986). Gill lesions were proportional to parasite intensity, in which the gill tissue was compromised in heavy infestation. Proliferative disturbances were found, including epithelial hyperplasia, desquamation, and mononuclear and eosinophilic infiltrate that culminated in necrosis. We did not observe a seasonality effect on the occurrence of P. africana. This ciliated protozoan causes compromised respiratory capacity that leads to severe gill lesions and currently is an important pathogen that afflicts intensive tilapia cultures in Brazil.

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The morphology and morphometric data of seven populations of Blepharisma sinuosum from southeastern Brazil were investigated. The description is based on live observations, protargol impregnation, and scanning electron microscopy. Blepharisma sinuosum measures 75-255µm in length and 25-93µm in width and has a spindle-shaped body, pink color, a single contractile vacuole located at the posterior end, 50 adoral membranelles, a conspicuous paroral, 17-35 somatic kineties, a moniliform macronucleus with 2-7 connected nodules, and 3-20 micronuclei. Morphological comparisons with similar species were performed and suggest that B. americanum is the junior synonym of B. sinuosum. The 18S rDNA gene sequence of B. sinuosum was obtained and compared with that of other Blepharisma species. The length and GC content of the obtained sequence is 1652bp and 47.03%, respectively, and has a very high structural similarity (99.9%) with the B. undulans sequence. The validity of the classification of Blepharisma species in morphonuclear subgenera is also discussed.

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