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1.
Sci Rep ; 8(1): 17189, 2018 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-30464297

RESUMO

Mesodinium spp. are commonly found in marine and brackish waters, and several species are known to contain red, green, or both plastids that originate from cryptophyte prey. We observed the seasonal succession of Mesodinium spp. in a Japanese brackish lake, and we analysed the origin and diversity of the various coloured plastids within the cells of Mesodinium spp. using a newly developed primer set that specifically targets the cryptophyte nuclear 18S rRNA gene. Mesodinium rubrum isolated from the lake contained only red plastids originating from cryptophyte Teleaulax amphioxeia. We identified novel Mesodinium sp. that contained only green plastids or both red and green plastids originating from cryptophytes Hemiselmis sp. and Teleaulax acuta. Although the morphology of the newly identified Mesodinium sp. was indistinguishable from that of M. rubrum under normal light microscopy, phylogenetic analysis placed this species between the M. rubrum/major species complex and a well-supported lineage of M. chamaeleon and M. coatsi. Close associations were observed in cryptophyte species composition within cells of Mesodinium spp. and in ambient water samples. The appearance of suitable cryptophyte prey is probably a trigger for succession of Mesodinium spp., and the subsequent abundance of Mesodinium spp. appears to be influenced by water temperature and dissolved inorganic nutrients.


Assuntos
Cilióforos/crescimento & desenvolvimento , Cilióforos/parasitologia , Criptófitas/classificação , Criptófitas/crescimento & desenvolvimento , Cilióforos/classificação , Cilióforos/genética , Análise por Conglomerados , Criptófitas/genética , DNA de Algas/química , DNA de Algas/genética , DNA de Protozoário/química , DNA de Protozoário/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Japão , Lagos/parasitologia , Filogenia , RNA Ribossômico 18S/genética , Estações do Ano , Análise de Sequência de DNA
2.
Protist ; 169(5): 662-681, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30125802

RESUMO

For years the genus Chroomonas was defined as being a cryptophyte with rectangular periplast plates, with a gullet and with biliprotein types PC 630 or 645. In phylogenetic trees the genus proved to be paraphyletic. Moreover, cells with hexagonal periplast plates were found in an SEM preparation from material of the type species C. nordstedtii. In this study, material of Hansgirg's C. nordstedtii was subjected to PCR and to sequencing of two short DNA tags. These tags allowed for an unambiguous identification of the real C. nordstedtii in the phylogeny of the blue-green cryptophytes. The genus Chroomonas corresponds to subclade 1, whereas subclades 3 and 4 do not belong to Chroomonas, if Hemiselmis is maintained. Additional examination by light and scanning electron microscopy and by spectrophotometry demonstrate that subclade 1 comprises only cells with hexagonal periplast plates and PC 630, whereas rectangular periplast plates are found only in subclades 3 and 4. Consequently the genus Chroomonas and its type species, C. nordstedtii, are revised and two novel species, C. debatzensis and C. gentoftensis sp. nov., are described.


Assuntos
Criptófitas/classificação , Criptófitas/genética , Criptófitas/crescimento & desenvolvimento , Criptófitas/ultraestrutura , DNA Ribossômico/genética , Microscopia Eletrônica de Varredura , Filogenia , Análise de Sequência de DNA
3.
J Phycol ; 54(5): 665-680, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30043990

RESUMO

Twenty years ago an Arctic cryptophyte was isolated from Baffin Bay and given strain number CCMP2045. Here, it was described using morphology, water- and non-water soluble pigments and nuclear-encoded SSU rDNA. The influence of temperature, salinity, and light intensity on growth rates was also examined. Microscopy revealed typical cryptophyte features but the chloroplast color was either green or red depending on the light intensity provided. Phycoerythrin (Cr-PE 566) was only produced when cells were grown under low-light conditions (5 µmol photons · m-2  · s-1 ). Non-water-soluble pigments included chlorophyll a, c2 and five major carotenoids. Cells measured 8.2 × 5.1 µm and a tail-like appendage gave them a comma-shape. The nucleus was located posteriorly and a horseshoe-shaped chloroplast contained a single pyrenoid. Ejectosomes of two sizes and a nucleomorph anterior to the pyrenoid were discerned in TEM. SEM revealed a slightly elevated vestibular plate in the vestibulum. The inner periplast component consisted of slightly overlapping hexagonal plates arranged in 16-20 oblique rows. Antapical plates were smaller and their shape less profound. Temperature and salinity studies revealed CCMP2045 as stenothermal and euryhaline and growth was saturated between 5 and 20 µmol photons · m-2  · s-1 . The phylogeny based on SSU rDNA showed that CCMP2045 formed a distinct clade with CCMP2293 and Falcomonas sp. isolated from Spain. Combining pheno- and genotypic data, the Arctic cryptophyte could not be placed in an existing family and genus and therefore Baffinellaceae fam. nov. and Baffinella frigidus gen. et sp. nov. were proposed.


Assuntos
Criptófitas/classificação , Criptófitas/citologia , Baías , Criptófitas/química , Criptófitas/crescimento & desenvolvimento , DNA de Algas/análise , DNA Ribossômico/análise , Nunavut , Filogenia , Pigmentação
4.
Opt Express ; 26(6): A251-A259, 2018 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-29609335

RESUMO

In view of the problem of the on-line measurement of algae classification, a method of algae classification and concentration determination based on the discrete three-dimensional fluorescence spectra was studied in this work. The discrete three-dimensional fluorescence spectra of twelve common species of algae belonging to five categories were analyzed, the discrete three-dimensional standard spectra of five categories were built, and the recognition, classification and concentration prediction of algae categories were realized by the discrete three-dimensional fluorescence spectra coupled with non-negative weighted least squares linear regression analysis. The results show that similarities between discrete three-dimensional standard spectra of different categories were reduced and the accuracies of recognition, classification and concentration prediction of the algae categories were significantly improved. By comparing with that of the chlorophyll a fluorescence excitation spectra method, the recognition accuracy rate in pure samples by discrete three-dimensional fluorescence spectra is improved 1.38%, and the recovery rate and classification accuracy in pure diatom samples 34.1% and 46.8%, respectively; the recognition accuracy rate of mixed samples by discrete-three dimensional fluorescence spectra is enhanced by 26.1%, the recovery rate of mixed samples with Chlorophyta 37.8%, and the classification accuracy of mixed samples with diatoms 54.6%.


Assuntos
Clorofila/análise , Eucariotos/química , Eucariotos/classificação , Espectrometria de Fluorescência , Clorofila A , Clorófitas/química , Clorófitas/classificação , Criptófitas/química , Criptófitas/classificação , Diatomáceas/química , Diatomáceas/classificação , Dinoflagelados/química , Dinoflagelados/classificação , Monitoramento Ambiental , Proliferação Nociva de Algas , Imagem Tridimensional , Análise de Ondaletas
5.
FEMS Microbiol Ecol ; 94(4)2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29360960

RESUMO

Photosynthetic picoeukaryotes (PPEs) play an important role in aquatic ecosystem functioning. There is still a relative lack of information on freshwater PPEs, especially in eutrophic lakes. We used a combination of flow cytometric sorting and pyrosequencing to investigate the PPEs community structure in more than 20 mesotrophic and eutrophic lakes along the middle-lower reaches of the Yangtze River in China. The abundance of PPEs ranged between 2.04 × 103 and 5.92 × 103 cells mL-1. The contribution of PPEs to total picophytoplankton abundance was generally higher in eutrophic lakes than in mesotrophic lakes. The sequencing results indicated that the Shannon diversity of PPEs was significantly higher in mesotrophic lakes than in eutrophic lakes. At the class level, PPEs were mainly dominated by three taxonomic groups, including Cryptophyceae, Coscinodiscophyceae and Chlorophyceae, and 15 additional known phytoplankton classes, including Synurophyceae, Dinophyceae, Chrysophyceae, Trebouxiophyceae and Prymnesiophyceae, were identified. Coscinodiscophyceae dominated in the most eutrophic lakes, while Chrysophyceae, Dinophyceae and other classes of PPEs were more abundant in the mesotrophic lakes. We also observed several PPEs operational taxonomic units, and those affiliated with Cyclotella atomus, Chlamydomonas sp. and Poterioochromonas malhamensis tended to be more prevalent in the eutrophic lakes. The canonical correspondence analysis and Mantel analysis highlighted the importance of environmental parameters as key drivers of PPEs community composition.


Assuntos
Chrysophyta/isolamento & purificação , Criptófitas/isolamento & purificação , Diatomáceas/isolamento & purificação , Dinoflagelados/isolamento & purificação , Haptófitas/isolamento & purificação , Lagos/parasitologia , Fitoplâncton/isolamento & purificação , Rios/parasitologia , Estramenópilas/isolamento & purificação , China , Clorófitas/classificação , Clorófitas/genética , Chrysophyta/classificação , Chrysophyta/genética , Criptófitas/classificação , Criptófitas/genética , Diatomáceas/classificação , Diatomáceas/genética , Dinoflagelados/classificação , Dinoflagelados/genética , Ecossistema , Citometria de Fluxo , Haptófitas/classificação , Haptófitas/genética , Fotossíntese , Fitoplâncton/classificação , Fitoplâncton/genética , Estramenópilas/classificação , Estramenópilas/genética
6.
FEMS Microbiol Ecol ; 94(2)2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29206918

RESUMO

Little is known about how various substances from living and decomposing aquatic macrophytes affect the horizontal patterns of planktonic bacterial communities. Study sites were located within Lake Kolon, which is a freshwater marsh and can be characterised by open-water sites and small ponds with different macrovegetation (Phragmites australis, Nymphea alba and Utricularia vulgaris). Our aim was to reveal the impact of these macrophytes on the composition of the planktonic microbial communities using comparative analysis of environmental parameters, microscopy and pyrosequencing data. Bacterial 16S rRNA gene sequences were dominated by members of phyla Proteobacteria (36%-72%), Bacteroidetes (12%-33%) and Actinobacteria (5%-26%), but in the anoxic sample the ratio of Chlorobi (54%) was also remarkable. In the phytoplankton community, Cryptomonas sp., Dinobryon divergens, Euglena acus and chrysoflagellates had the highest proportion. Despite the similarities in most of the measured environmental parameters, the inner ponds had different bacterial and algal communities, suggesting that the presence and quality of macrophytes directly and indirectly controlled the composition of microbial plankton.


Assuntos
Lagos/microbiologia , Lagos/parasitologia , Fitoplâncton/microbiologia , Fitoplâncton/parasitologia , Actinobacteria/classificação , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Bacteroidetes/classificação , Bacteroidetes/genética , Bacteroidetes/isolamento & purificação , Chlorobi/classificação , Chlorobi/genética , Chlorobi/isolamento & purificação , Criptófitas/classificação , Criptófitas/genética , Criptófitas/isolamento & purificação , Euglena/classificação , Euglena/genética , Euglena/isolamento & purificação , Água Doce/microbiologia , Água Doce/parasitologia , Magnoliopsida/crescimento & desenvolvimento , Microbiota , Nymphaea/crescimento & desenvolvimento , Filogenia , Fitoplâncton/classificação , Poaceae/crescimento & desenvolvimento , Proteobactérias/classificação , Proteobactérias/genética , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/genética
7.
Mar Drugs ; 16(1)2017 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-29278384

RESUMO

Microalgae have the ability to synthetize many compounds, some of which have been recognized as a source of functional ingredients for nutraceuticals with positive health effects. One well-known example is the long-chain polyunsaturated fatty acids (PUFAs), which are essential for human nutrition. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the two most important long-chain omega-3 (ω-3) PUFAs involved in human physiology, and both industries are almost exclusively based on microalgae. In addition, algae produce phytosterols that reduce serum cholesterol. Here we determined the growth rates, biomass yields, PUFA and sterol content, and daily gain of eight strains of marine cryptophytes. The maximal growth rates of the cryptophytes varied between 0.34-0.70 divisions day-1, which is relatively good in relation to previously screened algal taxa. The studied cryptophytes were extremely rich in ω-3 PUFAs, especially in EPA and DHA (range 5.8-12.5 and 0.8-6.1 µg mg dry weight-1, respectively), but their sterol concentrations were low. Among the studied strains, Storeatula major was superior in PUFA production, and it also produces all PUFAs, i.e., α-linolenic acid (ALA), stearidonic acid (SDA), EPA, and DHA, which is rare in phytoplankton in general. We conclude that marine cryptophytes are a good alternative for the ecologically sustainable and profitable production of health-promoting lipids.


Assuntos
Criptófitas/química , Ácidos Docosa-Hexaenoicos/análise , Ácido Eicosapentaenoico/análise , Biomassa , Criptófitas/classificação , Criptófitas/crescimento & desenvolvimento , Suplementos Nutricionais , Ácidos Graxos Ômega-3/análise , Ácidos Graxos Ômega-6/análise , Ácidos Graxos Insaturados/análise , Alimento Funcional , Cromatografia Gasosa-Espectrometria de Massas , Fitosteróis/análise
8.
Sci Rep ; 7(1): 2345, 2017 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-28539635

RESUMO

The chloroplasts of cryptophytes arose through a secondary endosymbiotic event in which a red algal endosymbiont was integrated into a previously nonphotosynthetic eukaryote. The cryptophytes retain a remnant of the endosymbiont nucleus (nucleomorph) that is replicated once in the cell cycle along with the chloroplast. To understand how the chloroplast, nucleomorph and host cell divide in a coordinated manner, we examined the expression of genes/proteins that are related to nucleomorph replication and chloroplast division as well as the timing of nuclear and nucleomorph DNA synthesis in the cryptophyte Guillardia theta. Nucleus-encoded nucleomorph HISTONE H2A mRNA specifically accumulated during the nuclear S phase. In contrast, nucleomorph-encoded genes/proteins that are related to nucleomorph replication and chloroplast division (FtsZ) are constantly expressed throughout the cell cycle. The results of this study and previous studies on chlorarachniophytes suggest that there was a common evolutionary pattern in which an endosymbiont lost its replication cycle-dependent transcription while cell-cycle-dependent transcriptional regulation of host nuclear genes came to restrict the timing of nucleomorph replication and chloroplast division.


Assuntos
Ciclo Celular , Núcleo Celular/metabolismo , Cloroplastos/metabolismo , Criptófitas/metabolismo , Replicação do DNA , Proteínas de Algas/genética , Proteínas de Algas/metabolismo , Sequência de Aminoácidos , Divisão Celular , Núcleo Celular/genética , Cloroplastos/genética , Criptófitas/classificação , Criptófitas/genética , Expressão Gênica , Histonas/genética , Histonas/metabolismo , Filogenia , Homologia de Sequência de Aminoácidos , Simbiose/genética , Fatores de Tempo
9.
FEMS Microbiol Ecol ; 93(4)2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28334157

RESUMO

Although they are widespread, diverse and involved in biogeochemical cycles, microbial eukaryotes attract less attention than their prokaryotic counterparts in environmental microbiology. In this study, we used publicly available 18S barcoding data to define biases that may limit such analyses and to gain an overview of the planktonic microbial eukaryotic diversity in freshwater ecosystems. The richness of the microbial eukaryotes was estimated to 100 798 operational taxonomic units (OTUs) delineating 1267 clusters or phylogenetic units (PUs, i.e. monophyletic groups of OTUs that are phylogenetically close). By summing the richness found in aquatic environments, we can predict the microbial eukaryotic richness to be around 200 000-250 000 species. The molecular diversity of protists in freshwater environments is generally higher than that of the morphospecies and cultivated species catalogued in public databases. Amoebozoa, Viridiplantae, Ichthyosporea, and Cryptophyta are the most phylogenetically diverse taxa, and characterisation of these groups is still needed. A network analysis showed that Fungi, Stramenopiles and Viridiplantae play central role in lake ecosystems. Finally, this work provides guidance for compiling metabarcoding data and identifies missing data that should be obtained to increase our knowledge on microbial eukaryote diversity.


Assuntos
Eucariotos/classificação , Plâncton/classificação , Criptófitas/classificação , Ecossistema , Fungos/classificação , Lagos/microbiologia , Filogenia , Estramenópilas/classificação
10.
J Eukaryot Microbiol ; 64(6): 740-755, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28258655

RESUMO

In a previous study, Teleaulax amphioxeia-the preferred prey of Mesodinium in the Columbia River estuary-were undetectable within intense annual blooms, suggesting blooms are prey-limited or prey are acquired outside of bloom patches. We used a novel molecular approach specifically targeting the prey (i.e., Unique Sequence Element [USE] within the ribosomal RNA 28S D2 regions of T. amphioxeia nucleus and nucleomorph) in estuarine water samples acquired autonomously with an Environmental Sample Processor integrated within a monitoring network (ESP-SATURN). This new approach allowed for both more specific detection of the prey and better constraint of sample variability. A positive correlation was observed between abundances of M. cf. major and T. amphioxeia during bloom periods. The correlation was stronger at depth (> 8.2 m) and weak or nonexistent in the surface, suggesting that predator-prey dynamics become uncoupled when stratification is strong. We confirmed exclusive selectivity for T. amphioxeia by M. cf. major and observed the incorporation of the prey nucleus into a 4-nuclei complex, where it remained functionally active. The specific biomarker for T. amphioxeia was also recovered in M. cf. major samples from a Namibian coastal bloom, suggesting that a specific predator-prey relationship might be widespread between M. cf. major and T. amphioxeia.


Assuntos
Cilióforos/crescimento & desenvolvimento , Cilióforos/isolamento & purificação , Criptófitas/crescimento & desenvolvimento , Criptófitas/isolamento & purificação , Ecossistema , Rios/microbiologia , Cilióforos/classificação , Cilióforos/genética , Análise por Conglomerados , Criptófitas/classificação , Criptófitas/genética , DNA de Algas/química , DNA de Algas/genética , DNA de Protozoário/química , DNA de Protozoário/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Estuários , Filogenia , Densidade Demográfica , RNA Ribossômico 28S/genética , Análise de Sequência de DNA
11.
Microbiologyopen ; 6(2)2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27868387

RESUMO

Concentrated seabed deposits of polymetallic nodules, which are rich in economically valuable metals (e.g., copper, nickel, cobalt, manganese), occur over vast areas of the abyssal Pacific Ocean floor. Little is currently known about the diversity of microorganisms inhabiting abyssal habitats. In this study, sediment, nodule, and water column samples were collected from the Clarion-Clipperton Zone of the Eastern North Pacific. The diversities of prokaryote and microeukaryote communities associated with these habitats were examined. Microbial community composition and diversity varied with habitat type, water column depth, and sediment horizon. Thaumarchaeota were relatively enriched in the sediments and nodules compared to the water column, whereas Gammaproteobacteria were the most abundant sequences associated with nodules. Among the Eukaryota, rRNA genes belonging to the Cryptomonadales were relatively most abundant among organisms associated with nodules, whereas rRNA gene sequences deriving from members of the Alveolata were relatively enriched in sediments and the water column. Nine operational taxonomic unit (OTU)s were identified that occur in all nodules in this dataset, as well as all nodules found in a study 3000-9000 km from our site. Microbial communities in the sediments had the highest diversity, followed by nodules, and then by the water column with <1/3 the number of OTUs as in the sediments.


Assuntos
Archaea/classificação , Criptófitas/classificação , Sedimentos Geológicos/microbiologia , Sedimentos Geológicos/parasitologia , Microbiota/genética , Proteobactérias/classificação , Organismos Aquáticos/classificação , Organismos Aquáticos/genética , Archaea/genética , Archaea/isolamento & purificação , Cobalto/isolamento & purificação , Cobre/isolamento & purificação , Criptófitas/genética , Criptófitas/isolamento & purificação , DNA Arqueal/genética , DNA Bacteriano/genética , DNA Ribossômico/genética , Manganês/isolamento & purificação , Níquel/isolamento & purificação , Oceano Pacífico , Proteobactérias/genética , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
12.
PLoS One ; 11(11): e0166338, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27861576

RESUMO

Tetrapyrroles such as chlorophyll and heme are indispensable for life because they are involved in energy fixation and consumption, i.e. photosynthesis and oxidative phosphorylation. In eukaryotes, the tetrapyrrole biosynthetic pathway is shaped by past endosymbioses. We investigated the origins and predicted locations of the enzymes of the heme pathway in the chlorarachniophyte Bigelowiella natans, the cryptophyte Guillardia theta, the "green" dinoflagellate Lepidodinium chlorophorum, and three dinoflagellates with diatom endosymbionts ("dinotoms"): Durinskia baltica, Glenodinium foliaceum and Kryptoperidinium foliaceum. Bigelowiella natans appears to contain two separate heme pathways analogous to those found in Euglena gracilis; one is predicted to be mitochondrial-cytosolic, while the second is predicted to be plastid-located. In the remaining algae, only plastid-type tetrapyrrole synthesis is present, with a single remnant of the mitochondrial-cytosolic pathway, a ferrochelatase of G. theta putatively located in the mitochondrion. The green dinoflagellate contains a single pathway composed of mostly rhodophyte-origin enzymes, and the dinotoms hold two heme pathways of apparently plastidal origin. We suggest that heme pathway enzymes in B. natans and L. chlorophorum share a predominantly rhodophytic origin. This implies the ancient presence of a rhodophyte-derived plastid in the chlorarachniophyte alga, analogous to the green dinoflagellate, or an exceptionally massive horizontal gene transfer.


Assuntos
Evolução Biológica , Vias Biossintéticas , Criptófitas/metabolismo , Diatomáceas/metabolismo , Dinoflagelados/metabolismo , Tetrapirróis/metabolismo , Vias Biossintéticas/genética , Criptófitas/classificação , Criptófitas/genética , Diatomáceas/classificação , Diatomáceas/genética , Dinoflagelados/classificação , Dinoflagelados/genética , Perfilação da Expressão Gênica , Heme/metabolismo , Filogenia , Sintase do Porfobilinogênio/genética , Sintase do Porfobilinogênio/metabolismo
13.
J Eukaryot Microbiol ; 63(6): 804-812, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27218475

RESUMO

We report a new heterotrophic cryptomonad Hemiarma marina n. g., n. sp. that was collected from a seaweed sample from the Republic of Palau. In our molecular phylogenetic analyses using the small subunit ribosomal RNA gene, H. marina formed a clade with two marine environmental sequences, and the clade was placed as a sister lineage of the freshwater cryptomonad environmental clade CRY1. Alternatively, in the concatenated large and small subunit ribosomal RNA gene phylogeny, H. marina was placed as a sister lineage of Goniomonas. Light and electron microscopic observations showed that H. marina shares several ultrastructural features with cryptomonads, such as flattened mitochondrial cristae, a periplast cell covering, and ejectisomes that consist of two coiled ribbon structures. On the other hand, H. marina exhibited unique behaviors, such as attaching to substrates with its posterior flagellum and displaying a jumping motion. H. marina also had unique periplast arrangement and flagellar transitional region. On the basis of both molecular and morphological information, we concluded that H. marina should be treated as new genus and species of cryptomonads.


Assuntos
Criptófitas/isolamento & purificação , Água do Mar/parasitologia , Criptófitas/classificação , Criptófitas/genética , Criptófitas/ultraestrutura , DNA Ribossômico/genética , Flagelos/genética , Flagelos/ultraestrutura , Processos Heterotróficos , Microscopia Eletrônica de Transmissão , Filogenia
14.
FEMS Microbiol Ecol ; 91(4)2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25764458

RESUMO

We analyzed the genetic diversity (V4 region of the 18S rRNA) of planktonic microbial eukaryotes in four high mountain lakes including two remote biogeographic regions (the Himalayan mountains and the European Alps) and distinct habitat types (clear and glacier-fed turbid lakes). The recorded high genetic diversity in these lakes was far beyond of what is described from high mountain lake plankton. In total, we detected representatives from 66 families with the main taxon groups being Alveolata (55.0% OTUs 97%, operational taxonomic units), Stramenopiles (34.0% OTUs 97%), Cryptophyta (4.0% OTUs 97%), Chloroplastida (3.6% OTUs 97%) and Fungi (1.7% OTUs 97%). Centrohelida, Choanomonada, Rhizaria, Katablepharidae and Telonema were represented by <1% OTUs 97%. Himalayan lakes harbored a higher plankton diversity compared to the Alpine lakes (Shannon index). Community structures were significantly different between lake types and biogeographic regions (Fisher exact test, P < 0.01). Network analysis revealed that more families of the Chloroplastida (10 vs 5) and the Stramenopiles (14 vs 8) were found in the Himalayan lakes than in the Alpine lakes and none of the fungal families was shared between them. Biogeographic aspects as well as ecological factors such as water turbidity may structure the microbial eukaryote plankton communities in such remote lakes.


Assuntos
Alveolados/classificação , Criptófitas/classificação , Fungos/classificação , Plâncton/classificação , Estramenópilas/classificação , Alveolados/genética , Áustria , Sequência de Bases , Biodiversidade , Criptófitas/genética , Ecologia , Ecossistema , Fungos/genética , Variação Genética/genética , Lagos , Nepal , Filogenia , Plâncton/genética , Análise de Sequência de DNA , Estramenópilas/genética
15.
Environ Microbiol ; 17(10): 3610-27, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25115943

RESUMO

Although inland water bodies are more heterogeneous and sensitive to environmental variation than oceans, the diversity of small protists in these ecosystems is much less well known. Some molecular surveys of lakes exist, but little information is available from smaller, shallower and often ephemeral freshwater systems, despite their global distribution and ecological importance. We carried out a comparative study based on massive pyrosequencing of amplified 18S rRNA gene fragments of protists in the 0.2-5 µm size range in one brook and four shallow ponds located in the Natural Regional Park of the Chevreuse Valley, France. Our study revealed a wide diversity of small protists, with 812 stringently defined operational taxonomic units (OTUs) belonging to the recognized eukaryotic supergroups (SAR--Stramenopiles, Alveolata, Rhizaria--Archaeplastida, Excavata, Amoebozoa, Opisthokonta) and to groups of unresolved phylogenetic position (Cryptophyta, Haptophyta, Centrohelida, Katablepharida, Telonemida, Apusozoa). Some OTUs represented deep-branching lineages (Cryptomycota, Aphelida, Colpodellida, Tremulida, clade-10 Cercozoa, HAP-1 Haptophyta). We identified several lineages previously thought to be marine including, in addition to MAST-2 and MAST-12, already detected in freshwater, MAST-3 and possibly MAST-6. Protist community structures were different in the five ecosystems. These differences did not correlate with geographical distances, but seemed to be influenced by environmental parameters.


Assuntos
Organismos Aquáticos/classificação , Biodiversidade , Eucariotos/classificação , Lagos , Alveolados/classificação , Alveolados/genética , Alveolados/isolamento & purificação , Organismos Aquáticos/genética , Organismos Aquáticos/isolamento & purificação , Criptófitas/classificação , Criptófitas/genética , Criptófitas/isolamento & purificação , Ecologia , Ecossistema , Eucariotos/genética , Eucariotos/isolamento & purificação , França , Fungos/genética , Haptófitas/classificação , Haptófitas/genética , Haptófitas/isolamento & purificação , Oceanos e Mares , Filogenia , RNA Ribossômico/genética , RNA Ribossômico/isolamento & purificação , Análise de Sequência de DNA , Estramenópilas/classificação , Estramenópilas/genética , Estramenópilas/isolamento & purificação
16.
Environ Microbiol ; 17(7): 2393-406, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25384623

RESUMO

Phytoflagellates <10 µm substantially contribute to the abundance, biomass and primary production in polar waters, but information on the distribution of specific groups is scarce. We applied catalysed reporter deposition-fluorescence in situ hybridization to investigate the distribution of total phytoflagellates and of eight specific groups along a 100 km transect west off Kongsfjorden (Spitsbergen) from 29 to 31 July 2010. Phytoflagellates contributed to >75% of the depth-integrated abundance and biomass of total eukaryotes <10 µm at all stations. Their depth-integrated abundance and biomass decreased along the transect from 1.5 × 10(12) cells m(-2) (6.6 × 10(12) pgC m(-2) ) at the outermost station to 1.7 × 10(10) cells m(-2) (4.7 × 10(10) pgC m(-2) ) at the innermost station. Chlorophytes contributed to the total abundance of phytoflagellates with a range from 13% to 87% (0.7-30.5 × 10(3) cells ml(-1) ), and predominated in open waters. The contribution of haptophytes was < 1-38% (10-4500 cells ml(-1) ). The other groups represented <10%. The temperature and salinity positively correlated with the total abundance of phytoflagellates, chlorophytes, haptophytes, bolidophytes and pelagophytes. Cryptophytes, pedinellids and pavlovophytes were negatively associated with the nutrient concentrations. The community composition of phytoflagellates changed along the transect, which could have implications on food web dynamics and biogeochemical cycles between the open ocean environment and Kongsfjorden investigated here.


Assuntos
Biomassa , Clorófitas/classificação , Estuários , Haptófitas/classificação , Regiões Árticas , Clorófitas/genética , Criptófitas/classificação , Criptófitas/genética , Meio Ambiente , Cadeia Alimentar , Haptófitas/genética , Hibridização in Situ Fluorescente , Svalbard
17.
J Eukaryot Microbiol ; 61(5): 480-92, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24913840

RESUMO

The cryptomonad Rhinomonas nottbecki n. sp., isolated from the Baltic Sea, is described from live and fixed cells studied by light, scanning, and transmission electron microscopy together with sequences of the partial nucleus- and nucleomorph-encoded 18S rRNA genes as well as the nucleus-encoded ITS1, 5.8S, ITS2, and the 5'-end of the 28S rRNA gene regions. The sequence analyses include comparison with 43 strains from the family Pyrenomonadaceae. Rhinomonas nottbecki cells are dorsoventrally flattened, obloid in shape; 10.0-17.2 µm long, 5.5-8.1 µm thick, and 4.4-8.8 µm wide. The inner periplast has roughly hexagonal plates. Rhinomonas nottbecki cells resemble those of Rhinomonas reticulata, but the nucleomorph 18S rRNA gene of R. nottbecki differs by 2% from that of R. reticulata, while the ITS region by 11%. The intraspecific variability in the ITS region of R. nottbecki is 5%. In addition, the predicted ITS2 secondary structures are different in R. nottbecki and R. reticulata. The family Pyrenomonadaceae includes three clades: Clade A, Clade B, and Clade C. All Rhinomonas sequences branched within the Clade C, while the genus Rhodomonas is paraphyletic. The analyses suggest that the genus Storeatula is an alternating morphotype of the genera Rhinomonas and Rhodomonas and that the family Pyrenomonadaceae includes some species that were described multiple times, as well as novel species.


Assuntos
Criptófitas/classificação , Criptófitas/isolamento & purificação , Filogenia , Água do Mar/parasitologia , Criptófitas/genética , Criptófitas/crescimento & desenvolvimento , DNA Espaçador Ribossômico/genética , Dados de Sequência Molecular
18.
Biol Direct ; 9: 7, 2014 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-24885221

RESUMO

Cryptomonads, are a lineage of unicellular and mostly photosynthetic algae, that acquired their plastids through the "secondary" endosymbiosis of a red alga - and still retain the nuclear genome (nucleomorph) of the latter. We find that the genome of the cryptomonad Guillardia theta comprises genes coding for 13 globin domains, of which 6 occur within two large chimeric proteins. All the sequences adhere to the vertebrate 3/3 myoglobin fold. Although several globins have no introns, the remainder have atypical intron locations. Bayesian phylogenetic analyses suggest that the G. theta Hbs are related to the stramenopile and chlorophyte single domain globins.


Assuntos
Criptófitas/genética , Hemoglobinas/genética , Sequência de Aminoácidos , Teorema de Bayes , Núcleo Celular/genética , Núcleo Celular/metabolismo , Criptófitas/classificação , Criptófitas/metabolismo , Hemoglobinas/classificação , Hemoglobinas/metabolismo , Filogenia , Plastídeos/genética , Plastídeos/metabolismo , Alinhamento de Sequência
19.
Sci Rep ; 4: 4641, 2014 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-24717814

RESUMO

Phylogenetic position of the marine biflagellate Palpitomonas bilix is intriguing, since several ultrastructural characteristics implied its evolutionary connection to Archaeplastida or Hacrobia. The origin and early evolution of these two eukaryotic assemblages have yet to be fully elucidated, and P. bilix may be a key lineage in tracing those groups' early evolution. In the present study, we analyzed a 'phylogenomic' alignment of 157 genes to clarify the position of P. bilix in eukaryotic phylogeny. In the 157-gene phylogeny, P. bilix was found to be basal to a clade of cryptophytes, goniomonads and kathablepharids, collectively known as Cryptista, which is proposed to be a part of the larger taxonomic assemblage Hacrobia. We here discuss the taxonomic assignment of P. bilix, and character evolution in Cryptista.


Assuntos
Criptófitas/classificação , Criptófitas/genética , Sequência de Aminoácidos , Sequência de Bases , Biodiversidade , Evolução Biológica , Linhagem da Célula , Evolução Molecular , Perfilação da Expressão Gênica , Dados de Sequência Molecular , Filogenia , Alinhamento de Sequência , Análise de Sequência de RNA , Transcriptoma/genética
20.
Mol Biol Evol ; 31(6): 1437-43, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24603278

RESUMO

Chlorarachniophytes and cryptophytes possess complex plastids that were acquired by the ingestion of a green and red algal endosymbiont, respectively. The plastids are surrounded by four membranes, and a relict nucleus, called the nucleomorph, remains in the periplastidal compartment, which corresponds to the remnant cytoplasm of the endosymbiont. Nucleomorphs contain a greatly reduced genome that possesses only several hundred genes with high evolutionary rates. We examined the relative transcription levels of the genes of all proteins encoded by the nucleomorph genomes of two chlorarachniophytes and three cryptophytes using an RNA-seq transcriptomic approach. The genes of two heat shock proteins, Hsp70 and Hsp90, were highly expressed under normal conditions. It has been shown that molecular chaperone overexpression allows an accumulation of genetic mutations in bacteria. Our results suggest that overexpression of heat shock proteins in nucleomorph genomes may play a role in buffering the mutational destabilization of proteins, which might allow the high evolutionary rates of nucleomorph-encoded proteins.


Assuntos
Clorófitas/genética , Criptófitas/genética , Chaperonas Moleculares/genética , Plastídeos/genética , Núcleo Celular/genética , Clorófitas/classificação , Clorófitas/citologia , Cromossomos , Criptófitas/classificação , Criptófitas/citologia , Evolução Molecular , Genomas de Plastídeos , Taxa de Mutação , Filogenia , Análise de Sequência de RNA , Simbiose , Regulação para Cima
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