Numerical and Thermal Response of the Bacterivorous Ciliate Colpidium kleini, a Species Potentially at Risk of Extinction by Rising Water Temperatures.

We investigated the food-dependent growth and thermal response of the freshwater ciliate Colpidium kleini using numerical response (NR) experiments. This bacterivorous ciliate occurs in lotic water and the pelagial of lakes and ponds. The C. kleini strain used in this work was isolated from a small alpine lake and identified by combining detailed morphological inspections with molecular phylogeny. Specific growth rates (rmax) were measured from 5 to 21 °C. The ciliate did not survive at 22 °C. The threshold bacterial food levels (0.3 - 2.2 × 106 bacterial cells mL-1) matched the bacterial abundance in the alpine lake from which C. kleini was isolated. The food threshold was notably lower than previously reported for C. kleini and two other Colpidium species. The threshold was similar to levels reported for oligotrich and choreotrich ciliates if expressed in terms of bacterial biomass (0.05 - 0.43 mg C L-1). From the NR results, we calculated physiological mortality rates at zero food concentration. The mean mortality (0.55 ± 0.17 d-1) of C. kleini was close to the mean estimate obtained for other planktonic ciliates that do not encyst. We used the data obtained by the NR experiments to fit a thermal performance curve (TPC). The TPC yielded a temperature optimum at 17.3 °C for C. kleini, a maximum upper thermal tolerance limit of 21.9 °C, and a thermal safety margin of 4.6 °C. We demonstrated that combining NR with TPC analysis is a powerful tool to predict better a species' fitness in response to temperature and food.

Mysterious sea urchin plague is spreading rapidly.

Pathogen that kills victims within days leaps from Caribbean to Red Sea.

New geographical records and molecular investigation of the ciliate Spirostomum.

Spirostomum is a genus of large ciliates, and its species are distributed worldwide. However, there has been limited research conducted on their geographical distribution and genomics. We obtained nine samples of ciliates from eight regions in Liaoning Province, China, and conducted a study on their geographical distribution and characteristics. Morphological and second-generation high-throughput sequencing methods were applied to identify the species, and a phylogenetic tree was established to gain a deeper understanding of the geographical distribution and evolutionary relationships of Spirostomum in Northeast China. The results identified Spirostomum yagiui and Spirostomum subtilis as a newly recorded species in Northeast China region. There are now five species of Spirostomum that have been recorded in China, and new details on the genomic characteristics of Spirostomum yagiui were provided. In addition, this study also identified the main branches of Spirostomum teres and Spirostomum minus in northern China, and provided a theoretical basis for the existence of hidden species. Spirostomum yagiui is the first species in the family Spirostomidae to have undergone mitochondrial genome sequencing.

Ciliate diversity in rodrigo de freitas lagoon (Rio de Janeiro, Brazil) from an integrative standpoint.

The Rodrigo de Freitas Lagoon is a highly eutrophic lacustrine system and has one of the longest histories of exploration and anthropic alteration in Brazil. Despite its relevance, limited studies explored the diversity of micro-eukaryotes in the lagoon. Ciliates (Alveolata, Ciliophora) are overlooked in environmental microbiology, especially in tropical and subtropical ecosystems, resulting in limited knowledge about their diversity and functional relevance in South American habitats, particularly in coastal lagoons. To fill this gap, here we investigated the diversity of ciliates in a brackish coastal lagoon in an urban area of Rio de Janeiro, Brazil, applying and comparing the performance of morphological and metabarcoding approaches. The metabarcoding analysis, based on high-throughput sequencing of the hipervariable region V4 of the 18S rRNA genes detected 37 molecular operational taxonomic units (MOTUs) assigned to Ciliophora, representing only about a half (56.9%) of the diversity detected by microscopy, which counted 65 ciliate morphotypes. The most representative classes in both approaches were Spirotrichea and Oligohymenophorea. The metabarcoding analysis revealed that 35.3% of the ciliate MOTUs had less than 97% similarity to available sequences in the NCBI database, indicating that more than one-third of these MOTUs potentially represents still not represented or undescribed ciliate species in current databases. Our findings indicate that metabarcoding techniques can significantly enhance the comprehension of ciliate diversity in tropical environments, but the scarcity of reference sequences of brackish ciliates in molecular databases represents a challenge to the taxonomic assignment of the MOTUs. This study provides new insights into the diversity of ciliates in a threatened coastal lagoon, revealing a vast array of still unknown and rare ciliate taxonomic units in tropical environments.

Reductitherus cryptostomus n. gen., n. sp. (Ciliophora: Armophorea: Clevelandellida), a remarkable new nyctotherid from an Australian cockroach, Parapanesthia gigantea (Blaberidae: Panesthiinae).

Ciliates of the family Nyctotheridae (Armophorea: Clevelandellida) are frequent intestinal symbionts of various invertebrates and some poikilotherm vertebrates. Depending on the classification scheme, there are between 15 and 18 recognized genera of Nyctotheridae, the majority of which exhibit a rather uniform morphology. They have round to ellipsoidal cells with an adoral zone of membranelles that begins anteriorly in an adoral groove and continues posteriorly into the buccal cavity where it extends deep into the cell in the peristomial funnel. The taxonomy of the Nyctotheridae is primarily based on the number and location of kinetal sutures. The only known divergence from the relatively conservative nyctortherid body plan are the bizarre symbionts of Panesthiinae cockroaches, ciliates of the family Clevelandellidae, which forms a clade nested within the Nyctotheridae genus Nyctotherus. In this study we report another ciliate that diverges morphologically from the canonical Nyctotheridae body plan, and which is also found in Panesthiinae hosts. The novel ciliate Reductitherus cryptostomus n. gen., n. sp. differs from the rest of Nyctotheridae by absence of the anterior adoral groove, a shortened adoral zone completely enclosed in a notably small buccal cavity, and two strongly reduced kinetal sutures, one left anterodorsal and the other right posterodorsal.

Novel identification of mixed infection of Lactococcus garvieae and Cryptocaryon irritans isolated from cultured Trachinotus ovatus in China.

Lactococcus garvieae has recently been identified and listed as one of the causative agents of hyperacute hemorrhagic sepsis in fish. In intensive recirculating aquaculture systems where there are high fish densities and minimal water changes, not only will it be conducive to the growth of bacteria, but Cryptocaryon irritans as a marine protozoan fish parasite is also prone to appear. This study reports the disease status of Trachinotus ovatus in an aquaculture area in Yangjiang City, Guangdong Province. Through the diagnosis of clinical symptoms of the diseased fish, identification of specific primers, 16s rRNA sequences phylogenetic tree analysis, physiological and biochemical identification, and observation of histopathological sections, the result of the experiment is that the mass death of T. ovatus is caused by a mixture of L. garvieae and C. irritants infections. Subsequently, regression infection experiments were performed to verify Koch's law. It was confirmed that the pathogen had strong virulence to T. ovatus. This is the first time that the co-infection of L. garvieae and C. irritans to T. ovatus was found in South China. The research results of this experiment have certain enlightenment significance for the epidemic trend of fish diseases in relevant sea areas.

First report of Trichodinella and new geographical records of trichodinids in Nile tilapia (Oreochromis niloticus) farmed in Brazil / Primeiro relato de Trichodinella e novos registros geográficos de tricodinídeos em tilapia do Nilo (Oreochromis niloticus) cultivada no Brasil

Abstract Massive occurrence of trichodinids is frequently accompanied by serious disease in fish farms. In this study, trichodinid species from the gills and skin of Nile tilapia (Oreochromis niloticus) farmed in the central-western region of Brazil (state of Goiás) were morphologically characterized. Dried slides were prepared from the parasites and were impregnated with silver nitrate (2%). Morphometric characteristics were determined and schematic drawings of the denticles were made using photomicrographs produced from the slides. Seven species of trichodinid ectoparasites (Protozoa: Ciliophora: Trichodinidae) were found parasitizing the gills: four of the genus Trichodina Ehrenberg, 1838; one of Tripartiella Lom, 1959; one of Paratrichodina Lom, 1963; and one of Trichodinella Ṧrámek-Huṧek, 1953. On the body surface, three specimens of the genus Trichodina were identified. This study presents new geographical records of trichodinids in Brazil, thus confirming that Trichodina centrostrigeata, Trichodina compacta, Trichodina heterodentata, Paratrichodina africana and Tripartiella orthodens are widely distributed worldwide. Additionally, the first record of the genus Trichodinella in Brazil is presented.

Resumo O parasitismo intenso por tricodinídeos está frequentemente relacionado à doença grave em fazendas de peixes. Neste estudo, espécies de tricodinídeos das brânquias e da pele de tilápias do Nilo (Oreochromis niloticus) cultivadas na região centro-oeste do Brasil (estado de Goiás) foram caracterizadas morfologicamente. As lâminas secas foram preparadas a partir dos parasitas e impregnadas com nitrato de prata (2%). As características morfométricas foram determinadas e desenhos esquemáticos dos dentículos foram confeccionados com fotomicrografias produzidas a partir das lâminas. Sete espécies de ectoparasitos tricodinídeos (Protozoa: Ciliophora: Trichodinidae) foram encontradas parasitando as brânquias: quatro do gênero Trichodina Ehrenberg, 1838; um de Tripartiella Lom, 1959; um de Paratrichodina Lom, 1963; e um de Trichodinella Ṧrámek-Huṧek, 1953. Na superfície do corpo, três espécimes do gênero Trichodina foram identificados. Este estudo apresenta novos registros geográficos de tricodinídeos no Brasil, confirmando que Trichodina centrostrigeata, Trichodina compacta, Trichodina heterodentata, Paratrichodina africana e Tripartiella orthodens estão amplamente distribuídas mundialmente. Adicionalmente, é apresentado o primeiro registro do gênero Trichodinella no Brasil.

Cryptocaryon irritans, a ciliate parasite of an ornamental reef fish yellowtail tang Zebrasoma xanthurum / Cryptocaryon irritans, parasito ciliado do peixe ornamental de recife "yellowtail tang" Zebrasoma xanthurum

Abstract Cryptocaryon irritans is an obligate parasitic ciliate protozoan of wild and cultured marine fish. It causes white spot disease, and infections with this pathogen can cause significant losses for aquarists and commercial marine cultures worldwide. This study reports the occurrence of C. irritans parasitizing the ornamental reef fish, yellowtail tang, Zebrasoma xanthurum. Six days after being introduced to a new environment, 11 yellowtail tangs had white spots scattered across their bodies and fins. Suspicion of infection with C. irritans was evaluated by scraping the skin to confirm clinical diagnosis. After confirmation, the yellowtail tangs were transferred to a hospital aquarium and treated with the therapeutic agent Seachem Cupramine® for 15 days. During the treatment period, the copper concentration was monitored daily. At the end of the treatment, none of the yellowtail tangs showed clinical signs of white spots on their bodies, and skin scraping confirmed the yellowtail tangs were no longer infected. Subsequently, the yellowtail tangs were released for sale.

Resumo Cryptocaryon irritans é um protozoário ciliado parasita obrigatório de peixes marinhos selvagens e cultivados. Causa a doença dos "pontos brancos". Infecções por esse patógeno pode causar perdas significativas para aquaristas e para marinocultura comercial em todo o mundo. Este estudo relata a ocorrência de C. irritans parasitando a espécie de peixe ornamental de recife Zebrasoma xanthurum. Seis dias após serem introduzidos no novo ambiente, onze peixes apresentaram pontos brancos espalhados pelo corpo e nadadeiras. Suspeitando de infecção por C. irritans foi realizado raspado de pele para confirmar o diagnóstico clínico. Após a confirmação, os peixes foram transferidos para um aquário hospital e tratados com o agente terapêutico Seachem Cupramine® por 15 dias. Durante o período de tratamento o monitoramento da concentração de cobre foi diário através da utilização de um fotômetro. Após o final do tratamento, todos os peixes já não apresentavam mais sinais clínicos de pontos brancos pelo corpo, e foram negativos no raspado de pele, sendo foram encaminhados para comercialização.

Association of Epistylis spp. (Ciliophora: Peritrichia) with parasitic crustaceans in farmed piava Megaleporinus obtusidens (Characiformes: Anostomidae) / Associação de Epistylis spp. (Ciliophora: Peritrichia) com crustáceos parasitas em piava Megaleporinus obtusidens de cultivo (Characiformes: Anostomidae)

Abstract Parasitic diseases have caused significant problems to global aquaculture production. These studies will further our knowledge of this complex problem and help implement adequate prevention measures and control strategies. The present study aimed to investigate the presence of parasites in Megaleporinus obtusidens and to describe the epidemiology and pathology of parasitic infections in these fish. Five moribund fish were sent for parasitological examination. The integument and gills were scrapped off with a glass slide, and samples were examined under a light microscope. Parasitic crustaceans found in these specimens were submitted for scanning electron microscopy and histological analyses. The crustaceans Dolops carvalhoi and Lernaea cyprinacea and the Epistylis spp. were present in all fish examined. Epistylis spp. were also seen on the entire surface of the crustacean integument. Microscopic lesions observed in the parasitized gills included hyperplasia and hypertrophy of the lamellar epithelium, an inflammatory infiltrate, telangiectasia, foci of hemorrhage and necrosis, fusion of the secondary lamellae, and detachment of the lamellar epithelium. Crustacean parasites are important mechanical vectors of Epistylis infection and disseminate the disease in fish farming operations. Epistylis spp. infection affects the health of fish and has significant ecological and economical impact on aquaculture.

Resumo Doenças parasitárias causam problemas significativos a produção mundial de peixes. Esse estudo aprofundará nosso conhecimento neste complexo problema e ajudará implementar estratégias de prevenção e controle. O objetivo deste trabalho foi analisar os parasitas encontrados em Megaleporinus obtusidens de piscicultura extensiva e descrever as relações epidemiológicas e patológicas entre eles. Cinco peixes moribundos foram enviados para análise parasitológica. O tegumento e as brânquias foram raspados com lâminas de vidro e examinados em microscópio óptico. Os crustáceos parasitas foram processados para análises histologicas e de microscopia eletrônica de varredura. Todos os peixes analisados foram infestados pelos crustáceos Dolops carvalhoi, Lernaea cyprinacea e pelo Epistylis spp. Epistylis spp. foram também encontrados na superfície de todo tegumento dos crustáceos parasitas. As brânquias parasitadas apresentaram hiperplasia e hipertrofia do epitélio lamelar, infiltrado inflamatório, telangectasia, focos hemorrágicos e necróticos, extensas áreas com fusão de lamelas secundárias e desprendimento de epitélio lamelar. Os crustáceos parasitas são vetores mecânicos importantes da epistilíase, disseminando o microorganismo nas criações de peixes. A infestação por Epistylis spp. afeta a saúde dos peixes e tem impacto ecológico e econômico significativo na aquacultura.

Protozoa ciliates community structure in urban streams and their environmental use as indicators / Estrutura da comunidade de protozoários ciliados em córregos urbanos e sua utilização como indicadores

Abstract The objective of this work was to investigate the patterns of diversity and abundance of ciliates protozoa community in three tropical urban streams and verify which species can be considered bioindicators of water quality. In each stream, three regions (headwater, middle and mouth) were sampled in two years, in the rainy and dry seasons. The abiotic factors (dissolved oxygen, pH, temperature, turbidity, width, depth, flow and conductivity) and biotic factors (total coliforms, bacterioplankton, chlorophyll and flagellates) were analyzed using appropriate methods and ciliates were identified and counted through specialized literature. We identified 84 species distributed into 24 orders. Peniculida was the most representative order followed by Prorodontida. The RDA scores showed a spatial difference between streams. On the other hand, regarding the temporal variation, there was no separation of the sampled data. The Indval analysis showed ten species indicators, such as Coleps hirtus, Euplotes moebiusi and Tintinidium pusillum. The Cluster analysis per stream versus period showed a greater distinction of the streams in the dry season. On the other hand, a low similarity was observed between sections within the same stream. In summary, the results indicated that the ciliates can be used as important tools as bioindicators in lotic environments affected by different degrees of pollution, due to the fact that they have short life cycle, allowing the detection of impacts on a small time scale, as well as by having direct answers to environmental changes and high sensitivity to contaminants.

Resumo O objetivo deste trabalho foi investigar os padrões de diversidade e abundância da comunidade de protozoários ciliados em três córregos urbanos tropicais, bem como verificar quais espécies podem ser consideradas bioindicadoras da qualidade da água. Em cada córrego foram amostradas três regiões (cabeceira, intermediária e foz) em dois anos, nas estações chuvosa e seca. Os fatores abióticos (oxigênio dissolvido, pH, temperatura, turbidez, largura, profundidade, fluxo e condutividade) e fatores bióticos (coliformes totais, bacterioplâncton, clorofila e flagelados) foram analisados ​​por metodologia específica e os ciliados foram contados e identificados por meio de literatura especializada. Foram identificadas 84 espécies distribuídas em 24 ordens. Peniculida foi a ordem mais representativa, seguida por Prorodontida. Os escores da RDA mostraram uma diferença espacial entre os córregos. Por outro lado, em relação à variação temporal, não houve separação entre os dados amostrados. A análise Indval mostrou dez espécies indicadoras, como Coleps hirtus, Euplotes moebiusi e Tintinidium pusillum. A análise de Cluster realizada por riacho versus período evidenciou uma maior distinção dos córregos no período seco. Por outro lado, foi observada uma baixa similaridade entre os locais dentro do mesmo córrego. Em síntese, os resultados indicaram que os ciliados podem ser utilizados como ferramentas importantes como bioindicadores em ambientes lóticos afetados por diferentes graus de poluição, devido ao fato de apresentarem um curto ciclo de vida, permitindo a detecção de impactos em uma pequena escala de tempo, bem como por apresentarem respostas diretas às mudanças ambientais e alta sensibilidade a contaminantes.

Spatial and temporal patterns of ciliate species composition (Protozoa: Ciliophora) in the plankton of the Upper Paraná River floodplain / Padrões espaciais e temporais da composição de espécies de ciliados (Protozoa: Ciliophora) no plâncton da planície de inundação do Alto Rio Paraná

Spatial and temporal patterns of plankton ciliates species composition in the Paraná River floodplain were investigated. Samplings were carried out in twelve environments in two distinct hydrological periods (limnophase and potamophase). A total of 61 species of ciliates were recorded, and among them 21 are classified as pelagic while 40 are considered preferentially as littoral species. The registered species belong to eleven orders, and among them, Prostomatida was the most specious followed by Hymenostomatida and Peritrichida. The ciliate species composition was significantly distinct between periods, but not among environments. In this way, typically pelagic species characterized the ciliate community during the limnophase period, while the littoral species were predominant during the potamophase period. Our results strongly support the idea of the flood pulse as the main factor driving the composition pattern of the planktonic ciliates community in the Paraná River floodplain.

No presente estudo foram investigados os padrões espaciais e temporais da composição de espécies de ciliados planctônicos na planície de inundação do Alto Rio Paraná. As amostras foram obtidas em 12 ambientes, em dois períodos hidrológicos distintos (limnofase e potamofase). Foram registradas 61 espécies de ciliados entre as quais 21 foram classificadas como pelágicas enquanto 40 foram consideradas preferencialmente litorâneas. As espécies registradas pertencem a 11 ordens, sendo Prostomatida foi a mais especiosa, seguida por Hymenostomatida e Peritrichida. A composição de espécies de ciliados foi significativamente distinta entre os períodos hidrológicos, enquanto que entre os ambientes, diferenças na composição não foram evidenciadas. Dessa forma, espécies tipicamente pelágicas caracterizaram a comunidade de ciliados na limnofase, enquanto que espécies litorâneas foram preponderantes para a composição de ciliados na potamofase. Os resultados suportam a idéia do pulso de inundação como principal fator controlador dos padrões de composição da comunidade de ciliados planctônicos na planície de inundação do Alto Rio Paraná.

Trichodina magna Van As and Basson, 1989 (Ciliophora: Peritrichia) from cultured Nile tilapia in the state of Santa Catarina, Brazil

Specimens of Trichodina magna Van As and Bassson, 1989 (Ciliophora: Peritrichia) from the Nile tilapia Oreochromis niloticus collected from October 2004 to June 2005 in fish ponds situated in three regions of Santa Catarina State, Brazil are described here. Wet smears of skin and gills were prepared in the field, air dried, impregnated with Klein’s dry silver method and Giemsa’s solution. From a total of 146 examined fish, 36 were parasitized on the skin, 14 in the gills and 33 on the skin and gills, simultaneously. The mean diameter of the body of the specimens of T. magna was 84.3 ± 12.6 µm, adhesive disc 60.7 ± 10.0 µm, denticulate ring, 38.3 ± 7.4 µm, consisting of 26 (23 to 29) denticles. The only distinguishable difference from the original description was the fact that the ray of the denticle is anteriorly directed and does not extend over the y + 1 axis.

Espécimes de Trichodina magna Van As e Bassson, 1989 (Ciliophora: Peritrichia) em tilápia do Nilo, Oreochromis niloticus coletada em viveiros, entre outubro de 2004 e junho de 2005, em três regiões do Estado de Santa Catarina, Brasil, são descritos. Esfregaços da pele e brânquias foram preparados em campo, secos e impregnados com nitrato de prata pelo método de Klein ou corados com Giemsa. De um total de 146 peixes examinados, 36 estavam parasitados na pele, 14 nas brânquias e 33 na pele e brânquias, simultaneamente. O diâmetro médio do corpo de T. magna foi 84,3 ± 12,6 µm, do disco adesivo 60,7 ± 10,0 µm, do anel denticulado 38,3 ± 7,4 µm consistindo de 26 (23 a 29) dentículos. A única diferença da descrição original é o fato do raio do dentículo ser anteriormente direcionado não ultrapassando o eixo y + 1.