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1.
Eur J Protistol ; 76: 125719, 2020 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-32736314

RESUMO

Studies of animal and plant microbiomes are burgeoning, but the majority of these focus on bacteria and rarely include microeukaryotes other than fungi. However, there is growing evidence that microeukaryotes living on and in larger organisms (e.g. plants, animals, macroalgae) are diverse and in many cases abundant. We present here a new combination of 'anti-metazoan' primers: 574*f-UNonMet_DB that amplify a wide diversity of microeukaryotes including some groups that are difficult to amplify using other primer combinations. While many groups of microeukaryotic parasites are recognised, myriad other microeukaryotes are associated with hosts as previously unknown parasites (often genetically divergent so difficult to amplify using standard PCR primers), opportunistic parasites, commensals, and other ecto- and endo-symbionts, across the 'symbiotic continuum'. These fulfil a wide range of roles from pathogenesis to mutually beneficial symbioses, but mostly their roles are unknown and likely fall somewhere along this spectrum, with the potential to switch the nature of their interactions with the host under different conditions. The composition and dynamics of host-associated microbial communities are also increasingly recognised as important moderators of host health. This 'pathobiome' approach to understanding disease is beginning to supercede a one-pathogen-one-disease paradigm, which cannot sufficiently explain many disease scenarios.

2.
Front Microbiol ; 10: 2373, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31708883

RESUMO

Apicomplexans are a group of microbial eukaryotes that contain some of the most well-studied parasites, including the causing agents of toxoplasmosis and malaria, and emergent diseases like cryptosporidiosis or babesiosis. Decades of research have illuminated the pathogenic mechanisms, molecular biology, and genomics of model apicomplexans, but we know little about their diversity and distribution in natural environments. In this study we analyze the distribution of apicomplexans across a range of both host-associated and free-living environments. Using publicly available small subunit (SSU) rRNA gene databases, high-throughput environmental sequencing (HTES) surveys, and our own generated HTES data, we developed an apicomplexan reference database, which includes the largest apicomplexan SSU rRNA tree available to date and encompasses comprehensive sampling of this group and their closest relatives. This tree allowed us to identify and correct incongruences in the molecular identification of apicomplexan sequences. Analyzing the diversity and distribution of apicomplexans in HTES studies with this curated reference database also showed a widespread, and quantitatively important, presence of apicomplexans across a variety of free-living environments. These data allow us to describe a remarkable molecular diversity of this group compared with our current knowledge, especially when compared with that identified from described apicomplexan species. This is most striking in marine environments, where potentially the most diverse apicomplexans apparently exist, but have not yet been formally recognized. The new database will be useful for microbial ecology and epidemiological studies, and provide valuable reference for medical and veterinary diagnosis especially in cases of emerging, zoonotic, and cryptic infections.

3.
Curr Biol ; 29(23): 4093-4101.e4, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31735677

RESUMO

The Fungi are a diverse kingdom, dominating terrestrial environments and driving important ecologies. Although fungi, and the related Opisthosporidia, interact with photosynthetic organisms on land and in freshwater as parasites, symbionts, and/or saprotrophic degraders [1, 2], such interactions in the marine environment are poorly understood [3-8]. One newly identified uncultured marine lineage has been named novel chytrid-like-clade-1 (NCLC1) [4] or basal-clone-group-I [5, 6]. We use ribosomal RNA (rRNA) encoding gene phylogenies to demonstrate that NCLC1 is a distinct branch within the Opisthosporidia (Holomycota) [7]. Opisthosporidia are a diverse and largely uncultured group that form a sister branch to the Fungi or, alternatively, the deepest branch within the Fungi, depending on how the boundary to this kingdom is inferred [9]. Using culture-free lineage-specific rRNA-targeted fluorescent in situ hybridization (FISH) microscopy, we demonstrate that NCLC1 cells form intracellular infection of key diatom species, establishing that intracellular colonization of a eukaryotic host is a consistent lifestyle across the Opisthosporidia [8-11]. NCLC1 infection-associated loss and/or envelopment of the diatom nuclei infers a necrotrophic-pathogenic interaction. Diatoms are one of the most diverse and ecologically important phytoplankton groups, acting as dominant primary producers and driving carbon fixation and storage in many aquatic environments [12-14]. Our results provide insight into the diversity of microbial eukaryotes that interact with diatoms. We suggest that such interactions can play a key role in diatom associated ecosystem functions, such as the marine carbon pump through necrotrophic-parasitism, facilitating the export of diatoms to the sediment [15, 16].

4.
Dalton Trans ; 48(43): 16312-16321, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31621718

RESUMO

Inclusion of the dithiadiazolyl and diselenadiazolyl radicals PhCNEEN (E = S, Se) into the porous framework, Al(bdc)(OH) [MIL-53(Al); bdc = 1,4-benzenedicarboxylate] was achieved by vacuum sublimation. PXRD studies reveal the inclusion complexes adopt the orthorhombic space group Imma. Variable temperature PXRD studies coupled with thermal analysis reveal that for PhCNSSN@MIL-53(Al), radical elimination from the pores at elevated temperatures is accompanied by an opening of the pore channels. Radicals can also be extracted from the framework using an appropriate solvent. Oxidation of the radical guest within the host framework has been achieved with Cl2 or Br2 and led to complete radical oxidation (based on EPR studies) whereas the milder oxidant I2 leads to incomplete oxidation.

5.
Chem Commun (Camb) ; 55(66): 9849-9852, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31364671

RESUMO

Reaction of the methyl-benzodithiazolyl radical (MBDTA) with M(hfac)2 complexes (M = Mn, Co, Zn) affords the complexes M(hfac)2(MBDTA)2. Strong antiferromagnetic exchange interactions are observed between M(ii) ions and the two S = 1/2 radicals (M = Mn, Co), whereas weak antiferromagnetic interactions are observed between radicals when using the diamagnetic Zn(ii) ion. Strong intermolecular exchange coupling is also evident in Mn(hfac)2(MBDTA)2 and attributed to π*-π* contacts between MBDTA radicals which are absent for the Co and Zn derivatives.

6.
Environ Microbiol ; 21(10): 3855-3861, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31278828

RESUMO

The application of metabarcoding to study animal-associated microeukaryotes has been restricted because the universal barcode used to study microeukaryotic ecology and distribution in the environment, the Small Subunit of the Ribosomal RNA gene (18S rRNA), is also present in the host. As a result, when host-associated microbial eukaryotes are analysed by metabarcoding, the reads tend to be dominated by host sequences. We have done an in silico validation against the SILVA 18S rRNA database of a non-metazoan primer set (primers that are biased against the metazoan 18S rRNA) that recovers only 2.6% of all the metazoan sequences, while recovering most of the other eukaryotes (80.4%). Among metazoans, the non-metazoan primers are predicted to amplify 74% of Porifera sequences, 4% of Ctenophora, and 15% of Cnidaria, while amplifying almost no sequences within Bilateria. In vivo, these non-metazoan primers reduce significantly the animal signal from coral and human samples, and when compared against universal primers provide at worst a 2-fold decrease in the number of metazoan reads and at best a 2800-fold decrease. This easy, inexpensive, and near-universal method for the study of animal-associated microeukaryotes diversity will contribute to a better understanding of the microbiome.


Assuntos
Cnidários/genética , Ctenóforos/genética , Código de Barras de DNA Taxonômico/métodos , Primers do DNA/genética , Poríferos/genética , Animais , Bases de Dados de Ácidos Nucleicos , Genes de RNAr/genética , Humanos , Filogenia , RNA Ribossômico 18S/genética
7.
Nature ; 568(7750): 103-107, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30944491

RESUMO

Apicomplexa is a group of obligate intracellular parasites that includes the causative agents of human diseases such as malaria and toxoplasmosis. Apicomplexans evolved from free-living phototrophic ancestors, but how this transition to parasitism occurred remains unknown. One potential clue lies in coral reefs, of which environmental DNA surveys have uncovered several lineages of uncharacterized basally branching apicomplexans1,2. Reef-building corals have a well-studied symbiotic relationship with photosynthetic Symbiodiniaceae dinoflagellates (for example, Symbiodinium3), but the identification of other key microbial symbionts of corals has proven to be challenging4,5. Here we use community surveys, genomics and microscopy analyses to identify an apicomplexan lineage-which we informally name 'corallicolids'-that was found at a high prevalence (over 80% of samples, 70% of genera) across all major groups of corals. Corallicolids were the second most abundant coral-associated microeukaryotes after the Symbiodiniaceae, and are therefore core members of the coral microbiome. In situ fluorescence and electron microscopy confirmed that corallicolids live intracellularly within the tissues of the coral gastric cavity, and that they possess apicomplexan ultrastructural features. We sequenced the genome of the corallicolid plastid, which lacked all genes for photosystem proteins; this indicates that corallicolids probably contain a non-photosynthetic plastid (an apicoplast6). However, the corallicolid plastid differs from all other known apicoplasts because it retains the four ancestral genes that are involved in chlorophyll biosynthesis. Corallicolids thus share characteristics with both their parasitic and their free-living relatives, which suggests that they are evolutionary intermediates and implies the existence of a unique biochemistry during the transition from phototrophy to parasitism.


Assuntos
Antozoários/parasitologia , Apicomplexa/genética , Apicomplexa/metabolismo , Clorofila/biossíntese , Genes de Protozoários/genética , Filogenia , Animais , Apicomplexa/citologia , Recifes de Corais , Dinoflagelados/citologia , Dinoflagelados/genética , Dinoflagelados/metabolismo , Genoma de Protozoário/genética , Fotossíntese , Plastídeos/genética , Simbiose
8.
J Am Chem Soc ; 141(17): 6875-6889, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30875208

RESUMO

The fluorescent 9'-anthracenyl-functionalized dithiadiazolyl radical (3) exhibits four structurally determined crystalline phases, all of which are monomeric in the solid state. Polymorph 3α (monoclinic P21/ c, Z' = 2) is isolated when the radical is condensed onto a cold substrate (enthalpically favored polymorph), whereas 3ß (orthorhombic P21 21 21, Z' = 3) is collected on a warm substrate (entropically favored polymorph). The α and ß polymorphs exhibit chemically distinct structures with 3α exhibiting face-to-face π-π interactions between anthracenyl groups, while 3ß exhibits edge-to-face π-π interactions. 3α undergoes an irreversible conversion to 3ß on warming to 120 °C (393 K). The ß-phase undergoes a series of reversible solid-state transformations on cooling; below 300 K a phase transition occurs to form 3γ (monoclinic P21/ c, Z' = 1), and on further cooling below 165 K, a further transition is observed to 3δ (monoclinic P21/ n, Z' = 2). Both 3ß â†’ 3γ and 3γ → 3δ transitions are reversible (single-crystal X-ray diffraction), and the 3γ → 3δ process exhibits thermal hysteresis with a clear feature observed by heat capacity measurements. Heating 3ß above 160 °C generates a fifth polymorph (3ε) which is distinct from 3α-3δ based on powder X-ray diffraction data. The magnetic behavior of both 3α and the 3ß/3γ/3δ system reflect an S = 1/2 paramagnet with weak antiferromagnetic coupling. The reversible 3δ ↔ 3γ phase transition exhibits thermal hysteresis of 20 K. Below 50 K, the value of χm T for 3δ approaches 0 emu·K·mol-1 consistent with formation of a gapped state with an S = 0 ground-state configuration. In solution, both paramagnetic 3 and diamagnetic [3][GaCl4] exhibit similar absorption and emission profiles reflecting similar absorption and emission mechanisms for paramagnetic and diamagnetic forms. Both emit in the deep-blue region of the visible spectrum (λem ∼ 440 nm) upon excitation at 255 nm with quantum yields of 4% (3) and 30% ([3][GaCl4]) affording a switching ratio [ΦF(3+)/ΦF(3)] of 7.5 in quantum efficiency with oxidation state. Solid-state films of both 3 and [3][GaCl4] exhibit emission bands at a longer wavelength (490 nm) attributed to excimer emission.

9.
J Eukaryot Microbiol ; 66(1): 4-119, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30257078

RESUMO

This revision of the classification of eukaryotes follows that of Adl et al., 2012 [J. Euk. Microbiol. 59(5)] and retains an emphasis on protists. Changes since have improved the resolution of many nodes in phylogenetic analyses. For some clades even families are being clearly resolved. As we had predicted, environmental sampling in the intervening years has massively increased the genetic information at hand. Consequently, we have discovered novel clades, exciting new genera and uncovered a massive species level diversity beyond the morphological species descriptions. Several clades known from environmental samples only have now found their home. Sampling soils, deeper marine waters and the deep sea will continue to fill us with surprises. The main changes in this revision are the confirmation that eukaryotes form at least two domains, the loss of monophyly in the Excavata, robust support for the Haptista and Cryptista. We provide suggested primer sets for DNA sequences from environmental samples that are effective for each clade. We have provided a guide to trophic functional guilds in an appendix, to facilitate the interpretation of environmental samples, and a standardized taxonomic guide for East Asian users.


Assuntos
Biodiversidade , Eucariotos/classificação , Filogenia , Terminologia como Assunto
10.
J Eukaryot Microbiol ; 66(4): 574-581, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30444565

RESUMO

Spores of the dinoflagellate Chytriodinium are known to infest copepod eggs causing their lethality. Despite the potential to control the population of such an ecologically important host, knowledge about Chytriodinium parasites is limited: we know little about phylogeny, parasitism, abundance, or geographical distribution. We carried out genome sequence surveys on four manually isolated sporocytes from the same sporangium, which seemed to be attached to a copepod nauplius, to analyze the phylogenetic position of Chytriodinium based on SSU and concatenated SSU/LSU rRNA gene sequences, and also characterize two genes related to the plastidial heme pathway, hemL and hemY. The results suggest the presence of a cryptic plastid in Chytriodinium and a photosynthetic ancestral state of the parasitic Chytriodinium/Dissodinium clade. Finally, by mapping Tara Oceans V9 SSU amplicon data to the recovered SSU rRNA gene sequences from the sporocytes, we show that globally, Chytriodinium parasites are most abundant within the pico/nano- and mesoplankton of the surface ocean and almost absent within microplankton, a distribution indicating that they generally exist either as free-living spores or host-associated sporangia.


Assuntos
Copépodes/parasitologia , Dinoflagelados/fisiologia , Genoma de Protozoário , Interações Hospedeiro-Parasita , Animais , Dinoflagelados/classificação , Dinoflagelados/genética , Genes de Protozoários , Genes de RNAr , Filogenia , Plastídeos/fisiologia
11.
J Eukaryot Microbiol ; 66(2): 281-293, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30028565

RESUMO

Environmental sequences have become a major source of information. High-throughput sequencing (HTS) surveys have been used to infer biogeographic patterns and distribution of broad taxa of protists. This approach is, however, more questionable for addressing low-rank (less inclusive) taxa such as species and genera, because of the increased chance of errors in identification due to blurry taxonomic boundaries, low sequence divergence, or sequencing errors. The specious ciliate genus Euplotes partially escapes these limitations. It is a ubiquitous, monophyletic taxon, clearly differentiated from related genera, and with a relatively well-developed internal systematics. It has also been the focus of several ecological studies. We present an update on Euplotes biogeography, taking into consideration for the first time environmental sequences, both traditional (Sanger) and HTS. We inferred a comprehensive small subunit rRNA gene phylogeny of the genus including a newly described marine species, Euplotes enigma, characterized by a unique question mark-shaped macronucleus. We then added available environmental sequences to the tree, mapping associated metadata. The resulting scenario conflicts on many accounts with previously held views, suggesting, for example, that a large diversity of anaerobic Euplotes species exist, and that marine representatives of mainly freshwater lineages (and vice-versa) might be more common than previously thought.


Assuntos
Euplotes/classificação , Euplotes/citologia , Euplotes/genética , Macronúcleo/fisiologia , Microscopia de Fluorescência , Filogenia , RNA de Protozoário/análise , RNA Ribossômico/análise
12.
J Eukaryot Microbiol ; 66(3): 519-524, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30080299

RESUMO

Recent surveys of marine microbial diversity have identified a previously unrecognized lineage of diplonemid protists as being among the most diverse heterotrophic eukaryotes in global oceans. Despite their monophyly (and assumed importance), they lack a formal taxonomic description, and are informally known as deep-sea pelagic diplonemids (DSPDs) or marine diplonemids. Recently, we documented morphology and molecular sequences from several DSPDs, one of which is particularly widespread and abundant in environmental sequence data. To simplify the communication of future work on this important group, here we formally propose to erect the family Eupelagonemidae to encompass this clade, as well as a formal genus and species description for the apparently most abundant phylotype, Eupelagonema oceanica, for which morphological information and single-cell amplified genome data are currently available.


Assuntos
Euglenozoários/classificação , Euglenozoários/citologia , Euglenozoários/genética , Filogenia , RNA de Protozoário/análise
13.
PLoS Biol ; 16(9): e2005849, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30222734

RESUMO

Environmental sequencing has greatly expanded our knowledge of micro-eukaryotic diversity and ecology by revealing previously unknown lineages and their distribution. However, the value of these data is critically dependent on the quality of the reference databases used to assign an identity to environmental sequences. Existing databases contain errors and struggle to keep pace with rapidly changing eukaryotic taxonomy, the influx of novel diversity, and computational challenges related to assembling the high-quality alignments and trees needed for accurate characterization of lineage diversity. EukRef (eukref.org) is an ongoing community-driven initiative that addresses these challenges by bringing together taxonomists with expertise spanning the eukaryotic tree of life and microbial ecologists, who use environmental sequence data to develop reliable reference databases across the diversity of microbial eukaryotes. EukRef organizes and facilitates rigorous mining and annotation of sequence data by providing protocols, guidelines, and tools. The EukRef pipeline and tools allow users interested in a particular group of microbial eukaryotes to retrieve all sequences belonging to that group from International Nucleotide Sequence Database Collaboration (INSDC) (GenBank, the European Nucleotide Archive [ENA], or the DNA DataBank of Japan [DDBJ]), to place those sequences in a phylogenetic tree, and to curate taxonomic and environmental information for the group. We provide guidelines to facilitate the process and to standardize taxonomic annotations. The final outputs of this process are (1) a reference tree and alignment, (2) a reference sequence database, including taxonomic and environmental information, and (3) a list of putative chimeras and other artifactual sequences. These products will be useful for the broad community as they become publicly available (at eukref.org) and are shared with existing reference databases.


Assuntos
Curadoria de Dados , Eucariotos/classificação , Eucariotos/genética , Variação Genética , Filogenia , RNA Ribossômico/genética , Cilióforos/genética , Bases de Dados Genéticas
14.
Sci Rep ; 8(1): 10665, 2018 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-30006614

RESUMO

(ND4)2[FeCl5(D2O)] represents a promising example of the hybrid molecular/inorganic approach to create materials with strong magneto-electric coupling. Neutron spherical polarimetry, which is directly sensitive to the absolute magnetic configuration and domain population, has been used in this work to unambiguously prove the multiferroicity of this material. We demonstrate that the application of an electric field upon cooling results in the stabilization of a single-cycloidal magnetic domain below 6.9 K, while poling in the opposite electric field direction produces the full population of the domain with opposite magnetic chirality. We prove the complete switchability of the magnetic domains at low temperature by the applied electric field, which constitutes a direct proof of the strong magnetoelectric coupling. Additionally, we refine the magnetic structure of the ordered ground state, deducing the underlying magnetic space group consistent with the direction of the ferroelectric polarization, and we provide evidence of a collinear amplitude-modulated state with magnetic moments along the a-axis in the temperature region between 6.9 and 7.2 K.

15.
Sci Rep ; 8(1): 9106, 2018 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-29904074

RESUMO

Although animals are among the best studied organisms, we still lack a full description of their diversity, especially for microscopic taxa. This is partly due to the time-consuming and costly nature of surveying animal diversity through morphological and molecular studies of individual taxa. A powerful alternative is the use of high-throughput environmental sequencing, providing molecular data from all organisms sampled. We here address the unknown diversity of animal phyla in marine environments using an extensive dataset designed to assess eukaryotic ribosomal diversity among European coastal locations. A multi-phylum assessment of marine animal diversity that includes water column and sediments, oxic and anoxic environments, and both DNA and RNA templates, revealed a high percentage of novel 18S rRNA sequences in most phyla, suggesting that marine environments have not yet been fully sampled at a molecular level. This novelty is especially high among Platyhelminthes, Acoelomorpha, and Nematoda, which are well studied from a morphological perspective and abundant in benthic environments. We also identified, based on molecular data, a potentially novel group of widespread tunicates. Moreover, we recovered a high number of reads for Ctenophora and Cnidaria in the smaller fractions suggesting their gametes might play a greater ecological role than previously suspected.


Assuntos
Organismos Aquáticos , Biodiversidade , Código de Barras de DNA Taxonômico , Nematoides , Platelmintos , Animais , Organismos Aquáticos/classificação , Organismos Aquáticos/genética , DNA de Helmintos/genética , Europa (Continente) , Nematoides/classificação , Nematoides/genética , Platelmintos/classificação , Platelmintos/genética , RNA de Helmintos/genética , RNA Ribossômico 18S/genética
16.
Environ Microbiol ; 20(6): 2218-2230, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29727060

RESUMO

High-throughput sequencing (HTS) surveys, among the most common approaches currently used in environmental microbiology, require reliable reference databases to be correctly interpreted. The EukRef Initiative (eukref.org) is a community effort to manually screen available small subunit (SSU) rRNA gene sequences and produce a public, high-quality and informative framework of phylogeny-based taxonomic annotations. In the context of EukRef, we present a database for the monophyletic phylum Ciliophora, one of the most complex, diverse and ubiquitous protist groups. We retrieved more than 11 500 sequences of ciliates present in GenBank (28% from identified isolates and 72% from environmental surveys). Our approach included the inference of phylogenetic trees for every ciliate lineage and produced the largest SSU rRNA tree of the phylum Ciliophora to date. We flagged approximately 750 chimeric or low-quality sequences, improved the classification of 70% of GenBank entries and enriched environmental and literature metadata by 30%. The performance of EukRef-Ciliophora is superior to the current SILVA database in classifying HTS reads from a global marine survey. Comprehensive outputs are publicly available to make the new tool a useful guide for non-specialists and a quick reference for experts.


Assuntos
Cilióforos/genética , Bases de Dados de Ácidos Nucleicos , Filogenia , RNA Ribossômico/genética , Sequenciamento de Nucleotídeos em Larga Escala
17.
Environ Microbiol ; 20(8): 2824-2833, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29687563

RESUMO

Apicomplexans are a group of obligate intracellular parasites, but their retention of a relict non-photosynthetic plastid reveals that they evolved from free-living photosynthetic ancestors. The closest relatives of apicomplexans include photosynthetic chromerid algae (e.g., Chromera and Vitrella), non-photosynthetic colpodellid predators (e.g., Colpodella) and several environmental clades collectively called Apicomplexan-Related Lineages (ARLs). Here we investigate the global distribution and inferred ecology of the ARLs by expansively searching for apicomplexan-related plastid small ribosomal subunit (SSU) genes in large-scale high-throughput bacterial amplicon surveys. Searching more than 220 million sequences from 224 geographical sites worldwide revealed 94 324 ARL plastid SSU sequences. Meta-analyses confirm that all ARLs are coral reef associated and not to marine environments generally, but only a subset is actually associated with coral itself. Most unexpectedly, Chromera was found exclusively in coral biogenous sediments, and not within coral tissue, indicating that it is not a coral symbiont, as typically thought. In contrast, ARL-V is the most diverse, geographically widespread and abundant of all ARL clades and is strictly associated with coral tissue and mucus. ARL-V was found in 19 coral species in reefs, including azooxanthellate corals at depths greater than 500 m. We suggest this is indicative of a parasitic or commensal relationship, and not of photosynthetic symbiosis, further underscoring the importance of isolating ARL-V and determining its relationship with the coral host.


Assuntos
Alveolados/fisiologia , Antozoários/parasitologia , Apicomplexa/classificação , Apicomplexa/fisiologia , Alveolados/genética , Animais , Biodiversidade , Recifes de Corais , Genes de Protozoários/genética , Genoma de Protozoário/genética , Sedimentos Geológicos , Interações Hospedeiro-Parasita , Plastídeos/genética , RNA Ribossômico 16S/genética , Subunidades Ribossômicas Menores
18.
Environ Microbiol ; 20(3): 1185-1203, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29417706

RESUMO

Although previous studies, mostly based on microscopy analyses of a few groups of protists, have suggested that protists are abundant and diverse in litter and moss habitats, the overall diversity of moss and litter associated protists remains elusive. Here, high-throughput environmental sequencing was used to characterize the diversity and community structure of litter- and moss-associated protists along a gradient of soil drainage and forest primary productivity in a temperate rainforest in British Columbia. We identified 3262 distinct protist OTUs from 36 sites. Protists were strongly structured along the landscape gradient, with a significant increase in alpha diversity from the blanket bog ecosystem to the zonal forest ecosystem. Among all investigated environmental variables, calcium content was the most strongly associated with the community composition of protists, but substrate composition, plant cover and other edaphic factors were also significantly correlated with these communities. Furthermore, a detailed phylogenetic analysis of unicellular opisthokonts identified OTUs covering most lineages, including novel OTUs branching with Discicristoidea, the sister group of Fungi, and with Filasterea, one of the closest unicellular relatives to animals. Altogether, this study provides unprecedented insight into the community composition of moss- and litter-associated protists.


Assuntos
Biodiversidade , Briófitas/parasitologia , Eucariotos/classificação , Eucariotos/isolamento & purificação , Solo/parasitologia , Animais , Ecossistema , Eucariotos/crescimento & desenvolvimento , Resíduos de Alimentos , Sequenciamento de Nucleotídeos em Larga Escala , Filogenia , Floresta Úmida , Solo/química
19.
Environ Microbiol ; 20(2): 815-827, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29215213

RESUMO

Photosynthetic picoeukaryotes contribute a significant fraction of primary production in the upper ocean. Micromonas pusilla is an ecologically relevant photosynthetic picoeukaryote, abundantly and widely distributed in marine waters. Grazing by protists may control the abundance of picoeukaryotes such as M. pusilla, but the diversity of the responsible grazers is poorly understood. To identify protists consuming photosynthetic picoeukaryotes in a productive North Pacific Ocean region, we amended seawater with living 15 N, 13 C-labelled M. pusilla cells in a 24-h replicated bottle experiment. DNA stable isotope probing, combined with high-throughput sequencing of V4 hypervariable regions from 18S rRNA gene amplicons (Tag-SIP), identified 19 operational taxonomic units (OTUs) of microbial eukaryotes that consumed M. pusilla. These OTUs were distantly related to cultured taxa within the dinoflagellates, ciliates, stramenopiles (MAST-1C and MAST-3 clades) and Telonema flagellates, thus, far known only from their environmental 18S rRNA gene sequences. Our discovery of eukaryotic prey consumption by MAST cells confirms that their trophic role in marine microbial food webs includes grazing upon picoeukaryotes. Our study provides new experimental evidence directly linking the genetic identity of diverse uncultivated microbial eukaryotes to the consumption of picoeukaryotic phytoplankton in the upper ocean.


Assuntos
Clorófitas/fisiologia , Cilióforos/metabolismo , Cadeia Alimentar , Fitoplâncton/fisiologia , Estramenópilas/metabolismo , Clorófitas/genética , Cilióforos/genética , Isótopos , Oceanos e Mares , Oceano Pacífico , Fotossíntese , Filogenia , Fitoplâncton/genética , RNA Ribossômico 18S/genética , Água do Mar/microbiologia , Água do Mar/parasitologia , Análise de Sequência de DNA , Estramenópilas/genética
20.
J Eukaryot Microbiol ; 65(1): 127-131, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28544317

RESUMO

The dinoflagellate Haidadinium ichthyophilum Buckland-Nicks, Reimchen and Garbary 1997 is an ectoparasite of the spine-deficient, three-spine stickleback Gasterosteus aculeatus L. Reimchen 1984, a fish endemic to Rouge Lake, Haida Gwaii. Haidadinium ichthyophilum proved difficult to assign taxonomically because its morphology and complex life cycle exhibited defining characteristics of both autotrophic and heterotrophic dinoflagellates, and was tentatively assigned to the Phytodiniales. Here, we characterized a 492 bp fragment of the small subunit ribosomal RNA (SSU rRNA) from preserved H. ichthyophilum cysts. In SSU phylogeny, H. ichthyophilum branches with the fish parasites, Piscinoodinium sp., strongly supporting the inclusion of H. ichthyophilum within the Suessiales.


Assuntos
Dinoflagelados/classificação , Smegmamorpha/parasitologia , Animais , Colúmbia Britânica , Dinoflagelados/genética , Lagos , Filogenia , RNA de Protozoário/análise , RNA Ribossômico/análise , Análise de Sequência de RNA/veterinária
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