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1.
BMC Microbiol ; 24(1): 27, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38243176

RESUMO

BACKGROUND: As unicellular eukaryotes, ciliates are an indispensable component of micro-ecosystems that play the role of intermediate nutrition link between bacteria or algae and meiofauna. Recent faunistic studies have revealed many new taxa of hypotrich ciliates, indicating their diversity is greater than previously thought. Here we document an undescribed form isolated from an artificial brackish water pond in East China. Examination of its morphology, ontogenesis and molecular phylogeny suggests that it represents a new species. RESULTS: The morphology and morphogenesis of the new brackish-water deviatid ciliate, Heterodeviata nantongensis nov. sp., isolated from Nantong, China, were investigated using live observations and protargol staining. The diagnostic traits of the new species include three frontal cirri, one buccal cirrus, one or two parabuccal cirri, an inconspicuous frontoventral cirral row of four to six frontoventral cirri derived from two anlagen, three left and two right marginal rows, two dorsal kineties, dorsal kinety 1 with 9-14 dikinetids and dorsal kinety 2 with only two dikinetids, and one to three caudal cirri at the rear end of dorsal kinety 1. Its main morphogenetic features are: (i) the old oral apparatus is completely inherited by the proter except undulating membranes, which are reorganized in situ; (ii) anlagen for marginal rows and the left dorsal kinety develop intrakinetally in both proter and opisthe; (iii) dorsal kinety 2 is generated dorsomarginally; (iv) five cirral anlagen are formed in both proter and opisthe; (v) in the proter, anlagen I and II very likely originate from the parental undulating membranes and the buccal cirrus, respectively, anlage III from anterior parabuccal cirrus, anlage IV originates from the parental frontoventral cirri and anlage V from the innermost parental right marginal row; and (vi) anlagen I-IV of the opisthe are all generated from oral primordium, anlage V from the innermost parental right marginal row. Phylogenetic analyses based on SSU rRNA gene sequence data were performed to determine the systematic position of the new taxon. CONCLUSIONS: The study on the morphology, and ontogenesis of a new brackish-water taxon increases the overall knowledge about the biodiversity of this ciliate group. It also adds to the genetic data available and further provides a reliable reference for environmental monitoring and resource investigations.


Assuntos
Alveolados , Cilióforos , Filogenia , Ecossistema , China , Água
2.
J Eukaryot Microbiol ; 71(1): e13001, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37746746

RESUMO

Strombidium is a species-rich genus of oligotrichid ciliates mainly inhabiting the marine pelagial. In molecular phylogenies, the genus emerged as non-monophyletic, and cladistic analyses suggest that it is largely characterized by plesiomorphies. A reliable split of the genus and the establishment of new genera necessitate, however, support by novel morphological and/or ultrastructural features. In the present study, the arrangement and ultrastructure of trichites are proposed as taxonomically relevant characters. Strombidium biarmatum Agatha et al., 2005 differs in the trichite pattern from the type species Strombidium sulcatum and most congeners. Aside from the trichites inserting anteriorly to the girdle kinety and generating the typical funnel-shaped complex in the posterior cell portion, the species displays additional trichites between the adoral membranelles even visible in live cells. Here, this exceptional trichite arrangement is detailed based on transmission electron microscopic investigations. In molecular phylogenies, S. biarmatum forms a monophylum with two congeners sharing its trichite arrangement. Therefore, the strombidiid genus Heteropilum nov. gen. is established with S. biarmatum as type species to also include H. paracapitatum (Song et al., 2015) nov. comb. and H. basimorphum (Martin & Montagnes, 1993) nov. comb. Further differences discovered in the trichite ultrastructure support the organelles' taxonomic significance.


Assuntos
Alveolados , Cilióforos , Filogenia , Organelas , Microscopia Eletrônica de Transmissão
3.
J Invertebr Pathol ; 202: 108044, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38123122

RESUMO

Perkinsosis has been recognized as one of the major threats to natural and farmed bivalve populations, many of which are of commercial as well as environmental significance. Three Perkinsus species have been identified in China, and the Manila clam (Ruditapes philippinarum) was the most frequently infected species in northern China. Although the occurrence and seasonal variation of Perkinsus spp. have previously been examined, the pathological characteristics of these infections in wild Manila clams and sympatric species in China have seldom been reported. In the present study, the prevalence and intensity of Perkinsus infection in wild populations of Manila clams and 10 sympatric species from three sites were investigated by Ray's fluid thioglycolate medium (RFTM) assay seasonally across a single year. Perkinsus infection was only identified in Manila clams, with a high prevalence (274/284 = 96.48 %) and low intensity (89.8 % with a Mackin value ≤ 2, suggesting generally low-intensity infections) throughout the year. Heavily infected clams were mainly identified in Tianheng in January, which displayed no macroscopic signs of disease. An overview of the whole visceral mass section showed that the trophozoites mostly aggregated in gills and connective tissue of the digestive tract, to a lesser extent in the mantle and foot, and even less frequently in adductor muscle and connective tissues of the gonad. PCR and ITS-5.8S rRNA sequencing of 93 representative RFTM-positive samples revealed a 99.69 to 100 % DNA sequence identity to Perkinsus olseni. Unexpectedly, significantly higher infection intensities were usually identified in January and April when the Condition Index (CI) was relatively high. We propose that factors associated with the anthropogenic harvesting pressure and irregular disturbances should be responsible for the uncommon seasonal infection dynamics of perkinsosis observed in the present study.


Assuntos
Alveolados , Bivalves , Animais , Estações do Ano , Sequência de Bases , Reação em Cadeia da Polimerase , China , Alveolados/genética
4.
Sci Rep ; 13(1): 20111, 2023 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-37978260

RESUMO

Perkinsea constitutes a lineage within the Alveolata eukaryotic superphylum, mainly composed of parasitic organisms. Some described species represent significant ecological and economic threats due to their invasive ability and pathogenicity, which can lead to mortality events. However, the genetic diversity of these described species is just the tip of the iceberg. Environmental surveys targeting this lineage are still scarce and mainly limited to the Northern Hemisphere. Here, we aim to conduct an in depth exploration of the Perkinsea group, uncovering the diversity across a variety of environments, including those beyond freshwater and marine ecosystems. We seek to identify and describe putative novel organisms based on their genetic signatures. In this study, we conducted an extensive analysis of a metabarcoding dataset, focusing on the V4 region of the 18S rRNA gene (the EukBank dataset), to investigate the diversity, distribution and environmental preferences of the Perkinsea. Our results reveal a remarkable diversity within the Perkinsea, with 1568 Amplicon Sequence Variants (ASVs) identified across thousands of environmental samples. Surprisingly, we showed a substantial diversity of Perkinsea within soil samples (269 ASVs), challenging the previous assumption that this group is confined to marine and freshwater environments. In addition, we revealed that a notable proportion of Perkinsea ASVs (428 ASVs) could correspond to putative new organisms, encompassing the well-established taxonomic group Perkinsidae. Finally, our study shed light on previously unveiled taxonomic groups, including the Xcellidae, and revealed their environmental distribution. These findings demonstrate that Perkinsea exhibits far greater diversity than previously detected and surprisingly extends beyond marine and freshwater environments. The meta-analysis conducted in this study has unveiled the existence of previously unknown clusters within the Perkinsea lineage, solely identified based on their genetic signatures. Considering the ecological and economic importance of described Perkinsea species, these results suggest that Perkinsea may play a significant, yet previously unrecognized, role across a wide range of environments, spanning from soil environments to the abyssal zone of the open ocean with important implications for ecosystem functioning.


Assuntos
Alveolados , DNA Ambiental , Alveolados/genética , Ecossistema , Filogenia , RNA Ribossômico 18S/genética , Solo , Biodiversidade , Código de Barras de DNA Taxonômico
5.
Parasitology ; 150(10): 939-949, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37565486

RESUMO

Perkinsus olseni is an industrially significant protozoan parasite of Manila clam, Ruditapes philippinarum. So far, various media, based on Dulbecco's Modified Eagle Medium and Ham's F-12 nutrient mixture with supplementation of fetal bovine serum (FBS), have been developed to proliferate the parasitizing trophozoite stage of P. olseni. The present study showed that P. olseni did not proliferate in FBS-deficient Perkinsus broth medium (PBMΔF), but proliferated well in PBMΔF supplemented with tissue extract of host Manila clams, indicating that FBS and Manila clam tissue contained molecule(s) required for P. olseni proliferation. Preliminary characterization suggested that the host-derived molecule(s) was a heat-stable molecule(s) with a molecular weight of less than 3 kDa, and finally a single molecule required for the proliferation was purified by high-performance liquid chromatography processes. High-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance analyses identified this molecule as glycine betaine (=trimethylglycine), and the requirement of this molecule for P. olsseni proliferation was confirmed by an assay using chemically synthesized, standard glycine betaine. Although glycine betaine was required for the proliferation of all examined Perkinsus species, supplementation of glycine betaine precursors, such as choline and betaine aldehyde, enhanced the proliferation of 4 Perkinsus species (P. marinus, P. chesapeaki, P. mediterraneus and P. honshuensis), but not of 2 others (P. olseni and P. beihaiensis). Thus, it was concluded that the ability to biosynthesise glycine betaine from its precursors varied among Perkinsus species, and that P. olseni and P. beihaiensis lack the ability required to biosynthesize glycine betaine for proliferation.


Assuntos
Alveolados , Bivalves , Parasitos , Animais , Betaína/farmacologia , Bivalves/parasitologia , Trofozoítos , Proliferação de Células
6.
J Eukaryot Microbiol ; 70(5): e12976, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37029732

RESUMO

The bulk of knowledge on marine ciliates is from shallow and/or sunlit waters. We studied ciliate diversity and distribution across epi- and mesopelagic oceanic waters, using DNA metabarcoding and phylogeny-based metrics. We analyzed sequences of the 18S rRNA gene (V4 region) from 369 samples collected at 12 depths (0-1000 m) at the Bermuda Atlantic Time-series Study site of the Sargasso Sea (North Atlantic) monthly for 3 years. The comprehensive depth and temporal resolutions analyzed led to three main findings. First, there was a gradual but significant decrease in alpha-diversity (based on Faith's phylogenetic diversity index) from surface to 1000-m waters. Second, multivariate analyses of beta-diversity (based on UniFrac distances) indicate that ciliate assemblages change significantly from photic to aphotic waters, with a switch from Oligotrichea to Oligohymenophorea prevalence. Third, phylogenetic placement of sequence variants and clade-level correlations (EPA-ng and GAPPA algorithms) show Oligotrichea, Litostomatea, Prostomatea, and Phyllopharyngea as anti-correlated with depth, while Oligohymenophorea (especially Apostomatia) have a direct relationship with depth. Two enigmatic environmental clades include either prevalent variants widely distributed in aphotic layers (the Oligohymenophorea OLIGO5) or subclades differentially distributed in photic versus aphotic waters (the Discotrichidae NASSO1). These results settle contradictory relationships between ciliate alpha-diversity and depth reported before, suggest functional changes in ciliate assemblages from photic to aphotic waters (with the prevalence of algivory and mixotrophy vs. omnivory and parasitism, respectively), and indicate that contemporary taxon distributions in the vertical profile have been strongly influenced by evolutionary processes. Integration of DNA sequences with organismal data (microscopy, functional experiments) and development of databases that link these sources of information remain as major tasks to better understand ciliate diversity, ecological roles, and evolution in the ocean.


Assuntos
Alveolados , Cilióforos , Oligoimenóforos , Filogenia , Alveolados/genética , Cilióforos/genética , RNA Ribossômico 18S/genética , Oligoimenóforos/genética , Oceanos e Mares
7.
Protist ; 174(2): 125949, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37019068

RESUMO

There are several alveolate groups outside the well-studied trio - ciliates, dinoflagellates, and apicomplexans - that are crucial for understanding the evolution of this major taxon. One such assemblage is the "colponemids", which are eukaryotrophic biflagellates, usually with a ventral groove associated with the posterior flagellum. Previous phylogenetic studies show colponemids forming up to three distinct deep branches within alveolates (e.g. sister groups to Myzozoa or all other alveolates). We have developed dieukaryotic (predator-prey) cultures of four colponemid isolates. One represents the first stable culture of the halophile Palustrimonas (feeding on Pharyngomonas), while SSU rDNA phylogenies show the other isolates as two distinct new lineages. Neocolponema saponarium gen. et sp. nov. is a swimming alkaliphile with a large groove, which feeds on a kinetoplastid. Loeffela hirca gen. et sp. nov. is halophilic, has a subtle groove, usually moves along surfaces, and feeds on Pharyngomonas and Percolomonas. Prey capture in both new genera is raptorial, involves a specialized structure/region to the right of the proximal posterior flagellum, and presumed extrusomes. The relationships amongst Myzozoa, ciliates, and the (now) five described colponemid clades are unresolved, signaling that colponemid diversity represents both a challenge and important resource for tracing deep alveolate evolution.


Assuntos
Alveolados , Dinoflagelados , Filogenia
8.
Parasit Vectors ; 16(1): 92, 2023 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-36882771

RESUMO

BACKGROUND: Chilodonella uncinata is an aerobic ciliate capable of switching between being free-living and parasitic on fish fins and gills, causing tissue damage and host mortality. It is widely used as a model organism for genetic studies, but its mitochondrial metabolism has never been studied. Therefore, we aimed to describe the morphological features and metabolic characteristics of its mitochondria. METHODS: Fluorescence staining and transmission electron microscopy (TEM) were used to observe the morphology of mitochondria. Single-cell transcriptome data of C. uncinata were annotated by the Clusters of Orthologous Genes (COG) database. Meanwhile, the metabolic pathways were constructed based on the transcriptomes. The phylogenetic analysis was also made based on the sequenced cytochrome c oxidase subunit 1 (COX1) gene. RESULTS: Mitochondria were stained red using Mito-tracker Red staining and were stained slightly blue by DAPI dye. The cristae and double membrane structures of the mitochondria were observed by TEM. Besides, many lipid droplets were evenly distributed around the macronucleus. A total of 2594 unigenes were assigned to 23 functional classifications of COG. Mitochondrial metabolic pathways were depicted. The mitochondria contained enzymes for the complete tricarboxylic acid (TCA) cycle, fatty acid metabolism, amino acid metabolism, and cytochrome-based electron transport chain (ETC), but only partial enzymes involved in the iron-sulfur clusters (ISCs). CONCLUSIONS: Our results showed that C. uncinata possess typical mitochondria. Stored lipid droplets inside mitochondria may be the energy storage of C. uncinata that helps its transmission from a free-living to a parasitic lifestyle. These findings also have improved our knowledge of the mitochondrial metabolism of C. uncinata and increased the volume of molecular data for future studies of this facultative parasite.


Assuntos
Alveolados , Cilióforos , Parasitos , Animais , Filogenia , Cilióforos/genética , Mitocôndrias
9.
Harmful Algae ; 123: 102390, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36894211

RESUMO

The number of perkinsozoan parasitoid species known to infect dinoflagellates has increased to 11 over the last two decades. However, most of the current knowledge about the autecology of perkinsozoan parasitoids of dinoflagellates has derived from studies of one or two species, thereby making it difficult to directly compare their biological traits at the same time and even their potentials as biological control agents if they are to be exploited to mitigate harmful dinoflagellate blooms in the field. This study investigated total generation time, the number of zoospores produced per sporangium, zoospore size, swimming speed, parasite prevalence, zoospore survival and success rate, and host range and susceptibility for five perkinsozoan parasitoids. Four of the species (Dinovorax pyriformis, Tuberlatum coatsi, Parvilucifera infectans, and P. multicavata) were from the family Parviluciferaceae and one (Pararosarium dinoexitiosum) was from the family Pararosariidae, with dinoflagellate Alexandrium pacificum employed as a common host. Distinct differences in the biological traits of the five perkinsozoan parasitoid species were found, suggesting that the fitness of these parasitoids for the common host species differs. These results thus offer useful background information for the understanding of the impacts of parasitoids on the natural host population and for the design of numerical modeling including the host-parasitoid systems and biocontrol experiments in the field.


Assuntos
Alveolados , Dinoflagelados , Dinoflagelados/parasitologia
10.
Trends Parasitol ; 39(3): 227-228, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36642690

Assuntos
Alveolados , Filogenia
11.
Curr Biol ; 33(1): R8-R10, 2023 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-36626865

RESUMO

Vanessa Smilansky and Thomas A. Richards introduce Perkinsea - a lineage of freshwater parasitic protists that infect certain amphibians and cause of severe Perkinsea infection.


Assuntos
Alveolados , Animais , Anfíbios , Água Doce
12.
Eur J Protistol ; 87: 125953, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36638556

RESUMO

The capsules, putative extrusomes in tintinnid ciliates, are known since 1971. Based on their ultrastructure, shape, and size, five capsule types were distinguished and suggested to be of phylogenetic significance. However, detailed morphometric data and transmission electron micrographs are lacking to verify former conclusions. In the current study, comprehensive analyses of transmission electron microscopic data were performed, investigating 14 species from 13 genera and more than seven families collected in European coastal waters and in the Northeast Pacific. Our data suggest two main capsule types (large and ampulliform vs small and ellipsoidal/ovoidal) each including two subtypes characterised by their internal structures. Species groupings inferred from the capsule (sub-)types emerge also as closely related in gene trees. Additionally, the ampulliform type unites the Undellidae, Xystonellidae, and Tintinnid clade 2, while the shared possession of the small ellipsoidal type proposes a close relationship of Tintinnid clade 11 with the Rhabdonellidae and Cyttarocylididae. Thus, the capsules provide promising features to shed light on several unresolved evolutionary relationships among tintinnid genera and families; yet, information on capsules is still missing for many monophyletic groupings. Finally, we provide the first ultrastructural clues for the extrusive character of these organelles.


Assuntos
Alveolados , Cilióforos , Filogenia , Cápsulas , Microscopia Eletrônica de Transmissão
13.
Chembiochem ; 24(3): e202200530, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36416092

RESUMO

Volatiles released by the apicomplexan alga Chromera velia CCAP1602/1 and their associated bacteria have been investigated. A metagenome analysis allowed the identification of the most abundant heterotrophic bacteria of the phycosphere, but the isolation of additional strains showed that metagenomics underestimated the complexity of the algal microbiome, However, a culture-independent approach revealed the presence of a planctomycete that likely represents a novel bacterial family. We analysed algal and bacterial volatiles by open-system-stripping analysis (OSSA) on Tenax TA desorption tubes, followed by thermodesorption, cryofocusing and GC-MS-analysis. The analyses of the alga and the abundant bacterial strains Sphingopyxis litoris A01A-101, Algihabitans albus A01A-324, "Coraliitalea coralii" A01A-333 and Litoreibacter sp. A01A-347 revealed sulfur- and nitrogen-containing compounds, ketones, alcohols, aldehydes, aromatic compounds, amides and one lactone, as well as the typical algal products, apocarotenoids. The compounds were identified by gas chromatographic retention indices, comparison of mass spectra and syntheses of reference compounds. A major algal metabolite was 3,4,4-trimethylcyclopent-2-en-1-one, an apocarotenoid indicating the presence of carotenoids related to capsanthin, not reported from algae so far. A low overlap in volatiles bouquets between C. velia and the bacteria was found, and the xenic algal culture almost exclusively released algal components.


Assuntos
Alveolados , Alveolados/metabolismo , Cromatografia Gasosa-Espectrometria de Massas/métodos , Espectrometria de Massas , Álcoois/metabolismo , Bactérias
14.
J Eukaryot Microbiol ; 70(2): e12958, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36458427

RESUMO

Ciliates usually with big cell sizes, complex morphological structures, and diverse life cycles, are good model organisms for studying cell proliferation regulation of eukaryotes. Up to date, the molecular regulation mechanisms for the vegetative cell cycle and encystment of these ciliates are poorly understood. Here, transcriptomes of Apodileptus cf. visscheri, which has an asexual vegetative cell cycle and is apt to encyst when environmental conditions become unfavorable, were sequenced to enrich our related knowledge. In this study, three replicates were sequenced for each of four cell stages, including initial period of growth, morphogenesis, cell division, and resting cyst. The significant transcription differences, involving cell cycle, biosynthesis, and energy metabolism pathways, were revealed between the resting cyst and vegetative cell cycle. Further investigations showed that the cell cycle pathway was enriched during morphogenesis stage and cell division stage. Compared to the initial period of growth stage, the differentially expressed genes involved in cellular components and molecular function were significantly enriched during cell division stage, while cellular components and biological processes were significantly enriched during morphogenesis stage. These provide novel insights into a comprehensive understanding at the molecular level of the survival and adaptive mechanism of unicellular eukaryotes.


Assuntos
Alveolados , Cilióforos , Alveolados/genética , Cilióforos/genética , Divisão Celular , Ciclo Celular , Transcriptoma
15.
Harmful Algae ; 120: 102352, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36470607

RESUMO

A new chytrid genus and species was isolated and cultured from samples obtained in the Baltic Sea during a dinoflagellate bloom event. This species is characterized by having a spherical sporangium without papillae and zoospores of 2-3 µm in diameter that are released through 3 discharge pores. Molecular phylogeny based on ribosomal operon showed its sister position to the Dinomyces cluster in Rhizophydiales. Zoospores lack fenestrated cisternae but contain a paracrystalline inclusion, found in a Rhizophydiales representative for the first time. Additionally, the kinetid features are uncommon for Rhizophydiales and only observed in Dinomyces representatives so far. These morphological features and its phylogenetic relationships justify the description of the new genus and speciesParadinomyces triforaminorum gen. nov. sp. nov. belonging to the family Dinomycetaceae. The chytrid was detected during a high-biomass bloom of the dinoflagellate Kryptoperidinium foliaceum. Laboratory experiments suggest this species is highly specific and demonstrate the impact it can have on HAB development. The chytrid co-occurred with three other parasites belonging to Chytridiomycota (Fungi) and Perkinsea (Alveolata), highlighting that parasitic interactions are common during HABs in brackish and marine systems, and these multiple parasites compete for similar hosts.


Assuntos
Alveolados , Quitridiomicetos , Dinoflagelados , Filogenia , Dinoflagelados/microbiologia
16.
Sci Rep ; 12(1): 18089, 2022 10 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
17.
Eur J Protistol ; 86: 125922, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36155308

RESUMO

Resting cysts protect ciliates against adverse environmental conditions. The morphology and ultrastructure of resting cysts has been described in very few Oligotrichea, a group of mainly marine planktonic ciliates. The present study provides the first ultrastructural data for loricate choreotrichids, applying light and electron microscopy on the cysts of the tintinnid Schmidingerella meunieri (Kofoid and Campbell, 1929) Agatha and Strüder-Kypke, 2012. The morphology of live cysts and the wall ultrastructure of cryofixed cysts were morphometrically analysed. The resting cyst is roughly flask-shaped, broadening to a slightly concave, laterally protruding anterior plate. An emergence pore closed by a skull cap-shaped papula is directed to the bottom of the lorica on the opposite side of the cyst. The cyst wall consists of an ectocyst, mesocyst, and endocyst differing in thickness, structure, and nitrogen concentration as revealed by conventional transmission electron microscopy, electron energy loss spectroscopy, and electron spectroscopic imaging. The cysts of S. meunieri belong to the kinetosome-resorbing type, which also occurs in the majority of hypotrich ciliates. Two main features (flask-shape and presence of an emergence pore) are shared with the closely related aloricate choreotrichids and oligotrichids, distinguishing the Oligotrichea from the hypotrich and the more distantly related euplotid ciliates.


Assuntos
Alveolados , Cilióforos , Filogenia , Cilióforos/ultraestrutura , Microscopia Eletrônica de Transmissão
18.
J Morphol ; 283(10): 1350-1358, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36059182

RESUMO

The Atlantic-Mediterranean polychaete Sabellaria spinulosa (Leuckart, 1849) lives in agglutinated tubes forming discrete reef-like bioconstructions on shallow-water bottoms beaten by waves where sediment particles are constantly resuspended. Tubes are built with sand grains glued by a proteinaceous cement. Analyses of a S. spinulosa reef sample of this worm collected off the Casarza coast (central Adriatic Sea) allowed the description of its tube architecture and gluing modality. The tube consists of three layers of agglutinated sand: (a) a thin inner layer with sandy particles arranged side by side with a flat side facing the tube lumen (b) a thick middle layer with larger isodiametric and squat grains with empty pores in between; and (c) a thin discontinuous outer layer of heterometric clasts, prevalently large and flat, diverging towards the opening. This fits the general tube construction known for S. alveolata and in general for tubes of the sabellariidae family, but compared to Sabellaria alveolata, S. spinulosa possesses a smaller tube with a wall about 1/3 thick; the agglutinated sandy elements are finer, and some number of muddy particles participates in the tube construction. Morphological and epifluorescence observations revealed that biocement portions are irregularly and haphazardly distributed compared with those of S. alveolata that consist of drops and strips of glue carefully placed. Adjacent tubes leave empty interspaces in between them only locally filled by loose sand, extremely reduced to absent in S. alveolata.


Assuntos
Alveolados , Poliquetos , Animais , Poliquetos/anatomia & histologia , Proteínas , Areia , Água
19.
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
20.
PLoS One ; 17(8): e0273096, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36026523

RESUMO

Bioconstructions of Sabellaria alveolata (Polychaeta Sabellariidae) from southern Sicily (Central Mediterranean) were sampled and analysed through a multidisciplinary approach in order to unravel the construction pattern of arenaceous tubes and explore possible analogies existing between the worm tubes and the agglutinated tests of benthic foraminifera (Protista). Scanning Electron Microscopy and Energy Dispersive Spectroscopy analyses were carried out on entire tubes as well as sectioned ones. Results show that arenaceous tubes are built following a rigorous architectural framework, based on selection and methodical arrangement of the agglutinated grains, and show surprising analogies with the test microstructure previously observed in agglutinated foraminifera. The grain distribution detected in both model species bioconstructions was analysed using a fractal numerical model (Hausdorff fractal dimension). Collected data show that in both organisms the grains were distributed according to a fractal model, indicating that the evolutionary process may have led to finding the same optimal constructive strategy across organisms with an independent evolutionary history, notwithstanding different geometrical scales. Furthermore, in sectioned tubes we observed microplastic fragments agglutinated within the arenaceous wall and in the inter-tube area. This unexpected finding shows that marine animals can be affected by microplastic pollution not only in soft tissues, but also engineered hard structures, and suggests the problem is more pervasive than estimated so far.


Assuntos
Alveolados , Foraminíferos , Poliquetos , Animais , Fractais , Microplásticos , Plásticos
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