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1.
Appl Environ Microbiol ; 88(22): e0132322, 2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36326264

RESUMO

During a series of blooms of Noctiluca scintillans and Mesodinium rubrum, we applied high-throughput sequencing of the 16S rRNA gene to investigate the population dynamics of free-living (FL) and particle-attached (PA) bacteria in an attempt to evaluate the influence of protozoan bloom-induced disturbances on the structuring of these two communities. Our findings revealed that the FL and PA bacterial community compositions (BCCs) displayed distinct profiles during sequential blooms, and the PA flora responded more dynamically to these pulse perturbations. The dominant bacterial groups (e.g., Flavobacteriaceae, Rhodobacteraceae, Vibrionaceae, and SAR11 subclade I) in these two communities displayed different levels of connectivity with the bloom-causative species and environmental factors. In addition, more FL bacterial groups were associated with M. rubrum, while more PA bacterial groups were related to N. scintillans. Potential endocytic bacteria of N. scintillans, particularly Vibrionaceae and Rickettsiaceae, opportunistically thrived at the peak of the bloom, suggesting that they could be important players influencing the dynamics and biogeochemical cycling of the blooms. Overall, disparities in the substrate preferences and thermal niches of various bacterial taxa as well as the short duration of the blooms (1 to 3 days) contributed to the diverse responses of the FL and PA bacterial communities to these protozoan blooms. Our research provides insight into the responses of FL and PA bacterial communities to blooms caused by protozoa like N. scintillans and M. rubrum and highlights the ecological significance of certain keystone bacterial groups during this kind of cosmopolitan protozoan bloom. IMPORTANCE Shifts in the bacterioplankton community composition during phytoplankton blooms have been studied extensively; however, investigations on protozoan blooms are rare. This study first evaluated the impact of perturbations caused by sequential protozoan blooms of the heterotrophic dinoflagellate Noctiluca scintillans and the mixotrophic ciliate Mesodinium rubrum on the structuring of these two bacterial communities. Our findings shed light on the responses of these two bacterial communities to such cosmopolitan protozoan blooms and highlight the possible ecological significance of certain keystone bacterial groups during these blooms. This research prepares the way for more focused studies that will help in understanding the roles that bacteria play during protozoan blooms and their impact on environmental health.


Assuntos
Cilióforos , Dinoflagelados , RNA Ribossômico 16S/genética , Fitoplâncton , Bactérias/genética
2.
Protist ; 173(5): 125909, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36208492

RESUMO

Three epibiotic Epistylis species, i.e., Epistylis weishanensis sp. nov., Epistylis daphniae Fauré-Fremiet, 1905, and Epistylis pygmaeum (Ehrenberg, 1838) Foissner et al., 1999, were investigated based on their living morphology, infraciliature, and small subunit (SSU) rDNA sequence data. Epistylis weishanensis sp. nov. is characterized by its double-layered peristomial lip, contractile vacuole located on the dorsal wall of the infundibulum, infundibular polykinety 3 (P3) composed of three equal-length rows that terminate above infundibular polykinety 1 (P1), 50-62 silverlines between the peristome and the trochal band, and about 30 silverlines between the trochal band and the scopula. Based on previous and newly obtained data for E. daphniae and E. pygmaeum, improved diagnoses and redescriptions are provided including, for the first time, data on their infraciliature. Phylogenetic analyses reveal that all three species do not group within the major clade of Epistylis, supporting the assertion that the genus Epistylis should be an assemblage of morphospecies and therefore needs to be revised.


Assuntos
Cilióforos , Oligoimenóforos , Lagos , Filogenia , Áreas Alagadas , Especificidade da Espécie , Cilióforos/genética , DNA Ribossômico/genética
3.
Mar Pollut Bull ; 184: 114216, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36215761

RESUMO

To evaluate the effects of nitrofurazone on functional processes in marine ecosystems, periphytic protozoan communities were exposed to different concentrations of the antibiotic for a 10-day duration. Species trait distributions in the tested communities were observed during exposure to five concentrations of nitrofurazone. A fuzzy coding system with seven traits and seventeen categories was used to summarize the changes in functional patterns of the test organisms. Nitrofurazone had a significant influence on the function process of the periphytic ciliate communities. Bacterivores with flattened bodies were sensitive to the toxicant whereas sessile and cylindrical raptors showed a high tolerance to nitrofurazone, invariably dominating communities exposed to high concentrations. Bootstrapped-average analysis demonstrated a significant change in functional patterns at highest nitrofurazone concentrations (8 mg l-1). Based on these findings, it is suggested that nitrofurazone may negatively influence ecosystem function in marine environments.


Assuntos
Cilióforos , Ecossistema , Nitrofurazona/toxicidade , Monitoramento Ambiental , Antibacterianos
4.
Sci Rep ; 12(1): 18089, 2022 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-36302793

RESUMO

Paramecium bursaria is a mixotrophic ciliate species, which is common in stagnant and slow-flowing, nutrient-rich waters. It is usually found living in symbiosis with zoochlorellae (green algae) of the genera Chlorella or Micractinium. We investigated P. bursaria isolates from around the world, some of which have already been extensively studied in various laboratories, but whose morphological and genetic identity has not yet been completely clarified. Phylogenetic analyses of the SSU and ITS rDNA sequences revealed five highly supported lineages, which corresponded to the syngen and most likely to the biological species assignment. These syngens R1-R5 could also be distinguished by unique synapomorphies in the secondary structures of the SSU and the ITS. Considering these synapomorphies, we could clearly assign the existing GenBank entries of P. bursaria to specific syngens. In addition, we discovered synapomorphies at amino acids of the COI gene for the identification of the syngens. Using the metadata of these entries, most syngens showed a worldwide distribution, however, the syngens R1 and R5 were only found in Europe. From morphology, the syngens did not show any significant deviations. The investigated strains had either Chlorella variabilis, Chlorella vulgaris or Micractinium conductrix as endosymbionts.


Assuntos
Alveolados , Chlorella vulgaris , Clorófitas , Cilióforos , Oligoimenóforos , Paramecium , Paramecium/genética , Filogenia , Clorófitas/genética , Simbiose/genética
5.
Protist ; 173(6): 125912, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36242851

RESUMO

Diverse and dynamic communities of ciliates and other microbes thrive in the natural environment, driving the functioning of aquatic ecosystems. Many microbes are present in very low numbers or are dormant in the 'seedbank', escaping detection in environmental surveys and, consequently, remaining underexplored. Here, we report an extraordinarily rare ciliate that was discovered after persistent exploration of freshwater anoxic sediments - Legendrea loyezae Fauré-Fremiet, 1908, a member of the Family Spathidiidae, Order Haptorida. In this study, we present the sixth account of the ciliate since 1908 and reveal its phylogenetic position with the first 18S rRNA data for the genus. We explain the key morphological features of the species, describing a remarkable behaviour in which the ciliate "shapeshifts'' due to its ability of controlled full extension and retraction of its tube-like tentacles. Our results shed light on the similarity of L. loyezae to another ciliate that was first described as Legendrea bellerophon, later moved under a new genus and named Thysanomorpha bellerophon. We question the validity of this taxonomic decision and, based on morphological characters and tentacle movement, we propose moving T. bellerophon back under Legendrea. This study demonstrates how continued and persistent exploration of natural habitats lead to the discovery of microbial communities and species.


Assuntos
Cilióforos , Ecossistema , Filogenia , DNA de Protozoário/genética , Cilióforos/genética , RNA Ribossômico 18S/genética
6.
PLoS One ; 17(10): e0275629, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36251723

RESUMO

A method for assessing the degree of impact of wastewater treatment plant discharge on receiving rivers was proposed, based on the structural indicators of the population of ciliated protozoa. It was shown that the ratio of attached, crawling and free-swimming forms in bottom sediments changes under the influence of discharge. In the points subject to organic pollution, the share of attached filter-feeding bacteriovorous ciliates increases in the assemblage of ciliated protozoa. The proposed Attached Form Index (AFI) takes this ratio into account. The use of AFI makes it possible to assess the restructuring of the assemblage of ciliated protozoa under the influence of point sources of pollution, to establish a zone of negative influence of runoff, to assess the degree of restoration of the aquatic ecosystem, as the influence of the pollution source weakened.


Assuntos
Cilióforos , Poluentes Químicos da Água , Purificação da Água , Ecossistema , Monitoramento Ambiental , Rios/química , Águas Residuárias
7.
Mol Phylogenet Evol ; 177: 107623, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36058509

RESUMO

Hitherto, the phylogeny of ciliated protists, an important group of model organisms in many fields, has been mainly based on a single marker gene (SSU rDNA, nuclear small subunit ribosomal RNA gene). However, there is increasing evidence showing this is insufficient to provide robust phylogenies and has resulted in confusing systematics in many ciliates groups. Among these, the phylogenies within family Deviatidae (Spirotrichea, Hypotrichia) are ambiguous due to the dependence on SSU rDNA and undersampling. Here, we provide eight new sequences and conduct phylogenetic analyses based on both multi-gene and single-gene to clarify evolutionary relationships among all deviatids for which gene sequence are available. The results reveal that: (1) the monophyly of Deviatidae is well-supported by both single-gene and concatenated data; (2) the presence of fine cirri and relatively wide spacing of these cirri within all rows are plesiomorphies of Deviatidae; (3) Pseudosincirra longicirrata is closely related to Deviata rositae, which is supported by their shared possession of dorsomarginal kineties; (4) phylogenetic analyses and approximately unbiased test based on multi-gene support a close relationship among taxa lacking dorsomarginal kineties (D. parabacilliformis, D. multilineae nov. spec., D. abbrevescens, D. brasiliensis and Perisincirra paucicirrata); (5) Deviatidae shows a close relationship with Dorsomarginalia and Strongylidium-Hemiamphisiella-Pseudouroleptus assemblage, suggesting the presence/absence of dorsomarginal kineties is phylogenetically informative in this family and presence of them may be a plesiomorphy. Based on the morphological, morphogenetic and phylogenetic data, the evolutionary relationships within Deviatidae are hypothesized, and a new ciliate, Deviata multilineae nov. spec., collected from China, is investigated.


Assuntos
Cilióforos , Hypotrichida , China , Cilióforos/genética , DNA Ribossômico/genética , Hypotrichida/genética , Morfogênese , Filogenia , Especificidade da Espécie
8.
Int J Mol Sci ; 23(18)2022 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-36142882

RESUMO

Stentor coeruleus is a ciliate known for its regenerative ability. Recent genome sequencing reveals that its spliceosomal introns are exceptionally small. We wondered whether the multimegadalton spliceosome has any unique characteristics for removal of the tiny introns. First, we analyzed intron features and identified spliceosomal RNA/protein components. We found that all snRNAs are present, whereas many proteins are conserved but slightly reduced in size. Some regulators, such as Serine/Arginine-rich proteins, are noticeably undetected. Interestingly, while most parts of spliceosomal proteins, including Prp8's positively charged catalytic cavity, are conserved, regions of branching factors projecting to the active site are not. We conjecture that steric-clash avoidance between spliceosomal proteins and a sharply looped lariat might occur, and splicing regulation may differ from other species.


Assuntos
Cilióforos , Precursores de RNA , Arginina/metabolismo , Cilióforos/genética , Íntrons/genética , Precursores de RNA/genética , Precursores de RNA/metabolismo , Splicing de RNA , RNA Nuclear Pequeno/genética , RNA Nuclear Pequeno/metabolismo , Serina/metabolismo , Spliceossomos/genética , Spliceossomos/metabolismo
9.
Sci Rep ; 12(1): 16123, 2022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-36167957

RESUMO

This study aimed to identify the mortality present in private fish farm Amyloodinium ocellatum and Cryptocaryon irritans were isolated from this outbreak affecting Liza carinata fingerlings at an earthen-based aquaculture facility in Damietta, Egypt. A total of 140 moribunds, L. carinata, were collected from the fish ponds during the mortality events. Physico-chemical analysis of water was analyzed. The skin, fins, gills, and eyes of each fish specimen were scraped gently onto slides in areas over 2 cm area. All smears were examined separately under the light microscope. Molecular identification of the parasites using analysis of ITS rDNA regions flanking both 18S and 28S rDNA genes of Amyloodinium protozoa and C. irritans. Identities of the detected parasites were confirmed by gene sequence and phylogenetic analysis. The majority of the examined fish (90%) were infected, 66.42% had a mixed infection, and 23.57% had a single infection either with A. ocellatum (10.71%) or C. irritans (12.85%).The mean intensity of A. ocellatum was 16.5 ± 2.03 in the skin and 13.18 ± 1.90 in the gills of infected fish, while that of C. irritans was 4.75 ± 1.05 in gills and 7.43 ± 1.45 in the skin, respectively. To control the emergent mortalities, affected ponds were treated using copper sulfate pentahydrate, hydrogen peroxides solutions, and amprolium hydrochloride powder in feed. Fish across the treated ponds were gradually improved with low morbidity and mortalityrates during the treatment period. The clinical disease was almost diminished at the end of the second week of treatment. Coinciding with the clinical improvement of the treated juveniles, microscopical examination of skin/gill scraps exhibited a marked decline in the number of protozoan parasites at the end of the second week of treatment.


Assuntos
Cilióforos , Dinoflagelados , Doenças dos Peixes , Parasitos , Smegmamorpha , Amprólio , Animais , Cilióforos/genética , Sulfato de Cobre , DNA Ribossômico , Dinoflagelados/genética , Egito , Doenças dos Peixes/genética , Peixes/genética , Hidrogênio , Parasitos/genética , Peróxidos , Filogenia , Pós , Smegmamorpha/genética , Água
10.
Zootaxa ; 5165(2): 191-216, 2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-36095472

RESUMO

Although the diversity (~35 species) and worldwide distribution of goats (Ruminantia, Bovidae, Caprinae) are significant, studies on the diversity of symbiont ciliates in these mammals are scarce in comparison to other ruminants. The present work is a review and checklist of species based on taxonomic, morphologic, and ecologic studies of rumen ciliate protozoa in goats, presenting geographic distribution and hosts, as well as estimating the macroevolutionary relationships of the species observed in the studies. To that end, all of the available literature on databases was reviewed, the schematic drawings were made based on information present in the original description of the taxa, and the phylogenetic relationships were inferred based on Maximum Likelihood and Bayesian Inference analyses. According to our review, 72 species and 14 genera of ciliates have been associated with goats. Through the analysis of the association between ciliate genera and caprine hosts, it was shown that ciliates are more associated with domestic animals (Capra hircus14 genera) than wild ones (Rupicapra rupicaprasix genera, Capra ibexone genus, Capra pyrenaicaone genus). Thirteen countries were identified in the distribution map as having had reports of ciliate species associated with goats. The interaction networks of ciliates and their hosts showed that the species of ciliates associated with goats also occur in other herbivore mammal species. The recovered phylogenetic hypotheses show that the ciliate species in goats form a non-monophyletic group with maximum and minimum ages of ~8.2My and ~2.4My. We have also found that a large portion of the studies on the diversity of ciliates in goats does not employ all necessary techniques in an integrative way, despite it being essential for detailed descriptions and better knowledge of this fraction of biodiversity.


Assuntos
Alveolados , Cilióforos , Animais , Teorema de Bayes , Cilióforos/genética , Cabras , Especificidade de Hospedeiro , Filogenia , Rúmen/parasitologia
11.
Zootaxa ; 5178(3): 393-400, 2022 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-36095727

RESUMO

The article presents the description of a new species of the suctorian genus Rhabdophrya inhabiting the body surface (cuticle) of harpacticoid copepod from Navy-Nagar, Mumbai intertidal coralline region, west coast of India, the Arabian Sea. The diagnosis of the genus is refined, all other species diagnoses and identification keys are presented.


Assuntos
Cilióforos , Copépodes , Animais , Índia
12.
Zootaxa ; 5138(4): 492-500, 2022 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-36095822

RESUMO

Three suctorian ciliate species, Paracineta livadiana (Mereschkowsky, 1881), Loricophrya bosporica Sergeeva Dovgal, 2014 and Acinetopsis lynni Baldrighi et al., 2020 are found as epibionts on meiobenthic nematodes in an oxygen minimum zone of the Arabian Sea. All three species are recorded here for the first time from the Indian Ocean.


Assuntos
Cilióforos , Cinetofragminóforos , Nematoides , Animais , Oceano Índico , Oxigênio
13.
ISME J ; 16(12): 2775-2787, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35986094

RESUMO

Understanding the biodiversity and genetics of gut microbiomes has important implications for host physiology and industrial enzymes, whereas most studies have been focused on bacteria and archaea, and to a lesser extent on fungi and viruses. One group, still underexplored and elusive, is ciliated protozoa, despite its importance in shaping microbiota populations. Integrating single-cell sequencing and an assembly-and-identification pipeline, we acquired 52 high-quality ciliate genomes of 22 rumen morphospecies from 11 abundant morphogenera. With these genomes, we resolved the taxonomic and phylogenetic framework that revised the 22 morphospecies into 19 species spanning 13 genera and reassigned the genus Dasytricha from Isotrichidae to a new family Dasytrichidae. Comparative genomic analyses revealed that extensive horizontal gene transfers and gene family expansion provided rumen ciliate species with a broad array of carbohydrate-active enzymes (CAZymes) to degrade all major kinds of plant and microbial carbohydrates. In particular, the genomes of Diplodiniinae and Ophryoscolecinae species encode as many CAZymes as gut fungi, and ~80% of their degradative CAZymes act on plant cell-wall. The activities of horizontally transferred cellulase and xylanase of ciliates were experimentally verified and were 2-9 folds higher than those of the inferred corresponding bacterial donors. Additionally, the new ciliate dataset greatly facilitated rumen metagenomic analyses by allowing ~12% of the metagenomic sequencing reads to be classified as ciliate sequences.


Assuntos
Cilióforos , Rúmen , Animais , Rúmen/microbiologia , Filogenia , Biomassa , Cilióforos/genética , Genômica , Bactérias/genética , Fungos
14.
Protist ; 173(5): 125905, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36027633

RESUMO

Loxodes is one of the best ecologically characterized ciliate genera with numerous intriguing physiological abilities, including gravity-sensing organelles and nitrate respiration. However, these cells have been considered challenging to cultivate in bulk, and are poorly preserved by conventional fixatives used for fluorescence microscopy. Here we describe methods to grow and harvest Loxodes cells in bulk with liquid soil extract medium, as well as a new fixative called ZFAE (zinc sulfate, formaldehyde, acetic acid, ethanol) that can fix Loxodes cells more effectively than buffered formaldehyde or methanol. We show that ZFAE is compatible with immunofluorescence and the nuclear stain DAPI. Loxodes is thus now amenable to long-term maintenance, large-scale growth, and modern cell biology investigations of monoclonal strains in laboratory conditions.


Assuntos
Cilióforos , Metanol , Fixadores , Nitratos , Sulfato de Zinco , Formaldeído , Microscopia de Fluorescência , Etanol , Solo
15.
Elife ; 112022 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-35924891

RESUMO

The giant ciliate Stentor coeruleus is a classical model system for studying regeneration and morphogenesis in a single cell. The anterior of the cell is marked by an array of cilia, known as the oral apparatus, which can be induced to shed and regenerate in a series of reproducible morphological steps, previously shown to require transcription. If a cell is cut in half, each half regenerates an intact cell. We used RNA sequencing (RNAseq) to assay the dynamic changes in Stentor's transcriptome during regeneration, after both oral apparatus shedding and bisection, allowing us to identify distinct temporal waves of gene expression including kinases, RNA -binding proteins, centriole biogenesis factors, and orthologs of human ciliopathy genes. By comparing transcriptional profiles of different regeneration events, we identified distinct modules of gene expression corresponding to oral apparatus regeneration, posterior holdfast regeneration, and recovery after wounding. By measuring gene expression after blocking translation, we show that the sequential waves of gene expression involve a cascade mechanism in which later waves of expression are triggered by translation products of early-expressed genes. Among the early-expressed genes, we identified an E2F transcription factor and the RNA-binding protein Pumilio as potential regulators of regeneration based on the expression pattern of their predicted target genes. RNAi-mediated knockdown experiments indicate that Pumilio is required for regenerating oral structures of the correct size. E2F is involved in the completion of regeneration but is dispensable for earlier steps. This work allows us to classify regeneration genes into groups based on their potential role for regeneration in distinct cell regeneration paradigms, and provides insight into how a single cell can coordinate complex morphogenetic pathways to regenerate missing structures.


Assuntos
Cilióforos , Sequência de Bases , Cilióforos/genética , Humanos , Interferência de RNA , Análise de Sequência de RNA , Transcriptoma
16.
Proc Natl Acad Sci U S A ; 119(36): e2203057119, 2022 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-36037375

RESUMO

Phosphorus (P) is a key nutrient limiting bacterial growth and primary production in the oceans. Unsurprisingly, marine microbes have evolved sophisticated strategies to adapt to P limitation, one of which involves the remodeling of membrane lipids by replacing phospholipids with non-P-containing surrogate lipids. This strategy is adopted by both cosmopolitan marine phytoplankton and heterotrophic bacteria and serves to reduce the cellular P quota. However, little, if anything, is known of the biological consequences of lipid remodeling. Here, using the marine bacterium Phaeobacter sp. MED193 and the ciliate Uronema marinum as a model, we sought to assess the effect of remodeling on bacteria-protist interactions. We discovered an important trade-off between either escape from ingestion or resistance to digestion. Thus, Phaeobacter grown under P-replete conditions was readily ingested by Uronema, but not easily digested, supporting only limited predator growth. In contrast, following membrane lipid remodeling in response to P depletion, Phaeobacter was less likely to be captured by Uronema, thanks to the reduced expression of mannosylated glycoconjugates. However, once ingested, membrane-remodeled cells were unable to prevent phagosome acidification, became more susceptible to digestion, and, as such, allowed rapid growth of the ciliate predator. This trade-off between adapting to a P-limited environment and susceptibility to protist grazing suggests the more efficient removal of low-P prey that potentially has important implications for the functioning of the marine microbial food web in terms of trophic energy transfer and nutrient export efficiency.


Assuntos
Cadeia Alimentar , Modelos Biológicos , Fósforo , Organismos Aquáticos , Cilióforos/fisiologia , Lipídeos de Membrana/metabolismo , Fosfolipídeos/metabolismo , Fósforo/metabolismo , Fitoplâncton/metabolismo , Rhodobacteraceae/fisiologia
17.
Zool Res ; 43(5): 827-842, 2022 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-35993134

RESUMO

During faunal studies of psammophilic ciliates along the coast of Qingdao, China, several marine karyorelictean species were isolated. Among them, four species within the genus Remanella were investigated, including two species new to science: i.e., R. rugosa, Remanella elongata sp. nov., Remanella aposinica sp. nov., and R. unicorpusculata. Remanella rugosa has been reported several times, but this study is the first to provide detailed morphological characters and phylogenetics. Remanella elongata sp. nov. can be distinguished from its congeners by the presence of complex cortical granules, fewer macronuclei, and longer body size. Remanella aposinica sp. nov. differs from its congeners by having 14-17 right lateral ciliary rows and 24-37 dikinetids of intrabuccal kinety. Poorly known Remanella rugosa var. unicorpusculata (Kahl, 1933) Foissner, 1996 should be elevated from subspecies to species level, Remanella unicorpusculata (Foissner, 1996) stat. nov., based on detailed redescriptions with statistical data, living morphology, infraciliature, and species definitions. Small subunit (SSU) rDNA was sequenced for the four species, and phylogenetic analysis revealed that all known taxa in Remanella formed the outline branch to the genus Loxodes with moderate to high bootstrap support among Remanella lineages.


Assuntos
Cilióforos , Animais , China , Cilióforos/classificação , Cilióforos/genética , DNA Ribossômico/genética , Filogenia
18.
Eur J Protistol ; 85: 125906, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35932643

RESUMO

The class Litostomatea Small & Lynn, 1981 is a morphologically diverse ciliate group including hundreds of free-living and endocommensal species. The genera Acropisthium Perty, 1852 and Balantidion Eberhard, 1862 previously consisted of one free-living freshwater species each. Here, we not only highlight additional morphological features of the two type species, but also investigate a new species, Balantidion foissneri sp. nov., isolated from a river flowing through Lake Weishan, China, based on complementary methods, i.e., living morphology, stained preparations, and 18S rRNA gene sequence data. Balantidion foissneri sp. nov. can be distinguished from the type species, B. pellucidum Eberhard, 1862, by the body size (115-170 × 50-80 µm vs. 70-100 × 25-45 µm in B. pellucidum), oral bulge (distinct vs. indistinct), extrusome shape (filiform vs. rod-shaped), and the number of somatic kineties (46-60 vs. 25-40). In Balantidion species, pre-encystment trophonts show similarly-shaped polymorphic cytoplasmic lepidosomes destined to adorn the outer surface of the resting cyst. Based on the current knowledge, assignment of Balantidion to the family Acropisthiidae Foissner & Foissner, 1988 is proposed. In addition, phylogenetic analyses based on molecular data show that the two Balantidion species form a fully-supported clade to which Acropisthium mutabile has a sister relationship.


Assuntos
Cilióforos , China , Água Doce , Filogenia , RNA Ribossômico 18S/genética
19.
Eur J Protistol ; 85: 125910, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35939868

RESUMO

In the present study, a new freshwater peniculid species, Frontonia apoelegans sp. nov., and two other peniculid species, Frontonia atra (Ehrenberg, 1833) Bütschli, 1889 and Stokesia vernalis Wenrich, 1929, were isolated from Lake Weishan wetland, northern China. Their morphology and infraciliature are described based on live observations and silver staining methods. The SSU rRNA gene sequences are also provided. Frontonia apoelegans sp. nov. is recognized by the following combination of characteristics: two contractile vacuoles located right-dorsally, without collecting canals; peniculi 1 and 2 four-rowed, peniculus 3 three-rowed with leftmost row containing only one kinetosome; 62-76 somatic kineties; three ophryokineties; and four or five postoral kineties. We also provide improved diagnoses for Frontonia atra and Stokesia vernalis based on current and previous reports. Comparisons with sequences of morphologically similar species clearly support the validity of the new species. Phylogenetic analyses based on SSU rRNA gene sequence data reveal that Frontonia species with two contractile vacuoles cluster in a single clade, indicating these species may have a common origin. The family Frontoniidae is non-monophyletic whereas the family Stokesiidae remains monophyletic according to our analyses.


Assuntos
Cilióforos , Oligoimenóforos , China , Cilióforos/genética , DNA de Protozoário/genética , Genes de RNAr/genética , Oligoimenóforos/genética , Filogenia
20.
Lab Chip ; 22(18): 3508-3520, 2022 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-35971861

RESUMO

Stentor coeruleus, a single-cell ciliated protozoan, is a model organism for wound healing and regeneration studies. Despite Stentor's large size (up to 2 mm in extended state), microdissection of Stentor remains challenging. In this work, we describe a hydrodynamic cell splitter, consisting of a microfluidic cross junction, capable of splitting Stentor cells in a non-contact manner at a high throughput of ∼500 cells per minute under continuous operation. Introduction of asymmetry in the flow field at the cross junction leads to asymmetric splitting of the cells to generate cell fragments as small as ∼8.5 times the original cell size. Characterization of cell fragment viability shows reduced 5-day survival as fragment size decreases and as the extent of hydrodynamic stress imposed on the fragments increases. Our results suggest that cell fragment size and composition, as well as mechanical stress, play important roles in the long-term repair of Stentor cells and warrant further investigations. Nevertheless, the hydrodynamic splitter can be useful for studying phenomena immediately after cell splitting, such as the closure of wounds in the plasma membrane which occurs on the order of 100-1000 seconds in Stentor.


Assuntos
Cilióforos , Microfluídica , Membrana Celular , Hidrodinâmica
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