Consulta: subjectFacets:"Protists"
Registros recuperados: 11
Data/hora: 01/06/2024 03:33:55

Molecular analyses of protists in long-term observation programmes—current status and future perspectives
Provedor de dados: 5
Autores: Stern, Rowena; Kraberg, Alexandra; Bresnan, Eileen; Kooistra, Wiebe H. C. F.; Lovejoy, Connie; Montresor, Marina; Moran, Xose Anxelu G.; Not, Fabrice; Salas, Rafael; Siano, Raffaele; Vaulot, Daniel; Amaral-zettler, Linda; Zingone, Adriana; Metfies, Katja.
Protists (microbial eukaryotes) are diverse, major components of marine ecosystems, and are fundamental to ecosystem services. In the last 10 years, molecular studies have highlighted substantial novel diversity in marine systems including sequences with no taxonomic context. At the same time, many known protists remain without a DNA identity. Since the majority of pelagic protists are too small to identify by light microscopy, most are neither comprehensively or regularly taken into account, particularly in Long-term Ecological Research Sites. This potentially undermines the quality of research and the accuracy of predictions about biological species shifts in a changing environment. The ICES Working Group for Phytoplankton and Microbial Ecology conducted...
Tipo: Text
Palavras-chave: Protists; Long-term Ecological Research Station; Molecular; Time-series; Questionnaire; Literature survey.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00455/56708/58470.pdf

Protists Within Corals: The Hidden Diversity
Provedor de dados: 5
Autores: Clerissi, Camille; Brunet, Sebastien; Vidal-dupiol, Jeremie; Adjeroud, Mehdi; Lepage, Pierre; Guillou, Laure; Escoubas, Jean Michel; Toulza, Eve.
Previous observations suggested that microbial communities contribute to coral health and the ecological resilience of coral reefs. However, most studies of coral microbiology focused on prokaryotes and the endosymbiotic algae Symbiodinium. In contrast, knowledge concerning diversity of other protists is still lacking, possibly due to methodological constraints. As most eukaryotic DNA in coral samples was derived from hosts, protist diversity was missed in metagenome analyses. To tackle this issue, we designed blocking primers for Scleractinia sequences amplified with two primer sets that targeted variable loops of the 18S rRNA gene (18SV1V2 and 18SV4). These blocking primers were used on environmental colonies of Pocillopora damicornis sensu lato from two...
Tipo: Text
Palavras-chave: Holobiont; Protists; Symbiosis; Metabarcoding; Blocking primer; Scleractinia; Pocillopora damicornis.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00457/56823/58661.pdf

Heterotrophic protists as a trophic link between picocyanobacteria and the pearl oyster Pinctada margaritifera in the Takapoto lagoon (Tuamotu Archipelago, French Polynesia)
Provedor de dados: 5
Autores: Loret, Pascale; Le Gall, Solange; Dupuy, Christine; Blanchot, Jean; Pastoureaud, Annie; Delesalle, Bruno; Caisey, Xavier; Jonquieres, Gerard.
Pearl oysters are farmed in oligotrophic tropical atoll lagoons where planktonic communities are dominated by production from cyanobacteria smaller than 2 pm. Paradoxically, the pearl oyster Pinctada margaritifera only retains particles larger than 2 Pm. In this study, we assess the relative contribution of hetero/mixotrophic microbiota to the available planktonic resource. In Takapoto Atoll, picocyanobacteria are the dominant biomass (20 mug C l(-1)). The carbon biomass of ciliates and dinoflagellates ranges from 1 to 24 and 0.5 to 5 mug C l(-1) respectively, with a mean of 6 mug C l(-1) for ciliates and 2 mug C l(-1) for dinoflagellates. The possible retention by P. margaritifera on a natural protist suspension was investigated. Due to its high clearance...
Tipo: Text
Palavras-chave: Trophic resource; Picoplankton; Pinctada margaritifera; Pearl oysters; Atoll lagoon; Protists.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/2000/publication-823.pdf

Pearl Oysters Pinctada margaritifera grazing on natural plankton in Ahe atoll lagoon (Tuamotu archipelago, French Polynesia)
Provedor de dados: 5
Autores: Fournier, Jonathan; Dupuy, Celie; Bouvy, Marc; Couraudon-reale, Marine; Charpy, Loic; Pouvreau, Stephane; Le Moullac, Gilles; Le Pennec, Marie-annick; Cochard, Jean-claude.
In atoll lagoons of French Polynesia, growth and reproduction of pearl oysters are mainly driven by plankton concentration. However, the actual diet of black-lip pearl oysters P. margaritifera in these lagoons is poorly known. To fill this gap, we used the flow through chamber method to measure clearance rates of P. margaritifera in Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia). We found : (i) that pearl oysters cleared plankton at a rate that was positively related to plankton biovolume, (ii) that nanoflagellates were the main source of carbon for the pearl oysters, (iii) that the quantity and origin of carbon filtrated by pearl oysters was highly dependent on the concentration and composition of plankton. These results provide essential...
Tipo: Text
Palavras-chave: Pinctada margaritifera; Clearance rates; French Polynesia; Phytoplankton; Protists.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00078/18888/16599.pdf

Methodology for Single-Cell Genetic Analysis of Planktonic Foraminifera for Studies of Protist Diversity and Evolution
Provedor de dados: 5
Autores: Weiner, Agnes K. M.; Morard, Raphael; Weinkauf, Manuel F. G.; Darling, Kate F.; André, Aurore; Quillévéré, Frédéric; Ujiie, Yurika; Douady, Christophe J.; De Vargas, Colomban; Kucera, Michal.
Single-cell genetic analysis is an essential method to investigate the biodiversity and evolutionary ecology of marine protists. In protist groups that do not reproduce under laboratory conditions, this approach provides the only means to directly associate molecular sequences with cell morphology. The resulting unambiguous taxonomic identification of the DNA sequences is a prerequisite for barcoding and analyses of environmental metagenomic data. Extensive single-cell genetic studies have been carried out on planktonic foraminifera over the past 20 years to elucidate their phylogeny, cryptic diversity, biogeography, and the relationship between genetic and morphological variability. In the course of these investigations, it has become evident that genetic...
Tipo: Text
Palavras-chave: Foraminifera; Protists; Single-cell genetics; Cryptic diversity; Comparability; Methods; Laboratory protocols; Standardization.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00383/49460/49938.pdf

Multiple microalgal partners in symbiosis with the acantharian Acanthochiasma sp. (Radiolaria)
Provedor de dados: 5
Autores: Decelle, Johan; Siano, Raffaele; Probert, Ian; Poirier, Camille; Not, Fabrice.
Acantharia (Radiolaria) are widespread and abundant heterotrophic marine protists, some of which can host endosymbiotic eukaryotic microalgae. Although this photosymbiotic association was first described at the end of the 19th century, the diversity of the symbiotic microalgae remains poorly characterized. Here, we examined the identity of the microalgae associated with the acantharian species Acanthochiasma sp. by sequencing partial 18S and internal transcribed spacer (ITS) ribosomal DNA genes from cultured symbionts and directly from isolated holobiont specimens. Single Acanthochiasma cells contained multiple symbiotic partners, including distantly related dinoflagellates (Heterocapsa sp., Pelagodinium sp., Azadinium sp. and Scrippsiella sp.) as well as...
Tipo: Text
Palavras-chave: Photosymbiosis; Radiolaria; Acantharia; Protists; Microalgae; Plankton.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00114/22493/21497.pdf

Analysis of the genomic basis of functional diversity in dinoflagellates using a transcriptome-based sequence similarity network
Provedor de dados: 5
Autores: Meng, Arnaud; Corre, Erwan; Probert, Ian; Gutierrez-rodriguez, Andres; Siano, Raffaele; Annamale, Anita; Alberti, Adriana; Da Silva, Corinne; Wincker, Patrick; Le Crom, Stephane; Not, Fabrice; Bittner, Lucie.
Dinoflagellates are one of the most abundant and functionally diverse groups of eukaryotes. Despite an overall scarcity of genomic information for dinoflagellates, constantly emerging high-throughput sequencing resources can be used to characterize and compare these organisms. We assembled de novo and processed 46 dinoflagellate transcriptomes and used a sequence similarity network (SSN) to compare the underlying genomic basis of functional features within the group. This approach constitutes the most comprehensive picture to date of the genomic potential of dinoflagellates. A core-predicted proteome composed of 252 connected components (CCs) of putative conserved protein domains (pCDs) was identified. Of these, 206 were novel and 16 lacked any functional...
Tipo: Text
Palavras-chave: Genomics; Proteomics; Microbial biology; Molecular evolution; Protists; Transcriptomics.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00444/55550/57209.pdf

Cabra reticulata sp. nov. (Dinophyceae), a new sand-dwelling dinoflagellate from the Atlantic Ocean
Provedor de dados: 5
Autores: Chomerat, Nicolas; Nezan, Elisabeth.
A new sand-dwelling dinoflagellate species, Cabra reticulata sp. nov., is described from sandy habitats in the south of Brittany (northwestern France). This new species possesses the characteristics of the 'unusual' genus, Cabra Murray et Patterson. The thecal plate formula is Po Pt 3' 1a 4'' 'x' 3c ?s 5''' 1'''' (or alternatively interpreted as Po Pt 4' 0a 4'' 'x' 3c ?s 5''' 1''''). Because of the strong lateral compression, cells of C. reticulata are frequently seen laterally and have a polygonal shape, with three prominent antapical pointed flanges and a dorsal spine in the anterior part of the hypotheca. The cingulum is ascending and incomplete. The thecal surface is ornamented with strong reticulations forming polygonal areolae, which differs from C....
Tipo: Text
Palavras-chave: Taxonomy; Sand dwelling; Roscoffia; Protists; Podolampaceae; Marine; Dinophyceae; Benthic.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6804.pdf

Impact of the oyster Crassostrea gigas on a microbial community in Atlantic coastal ponds near La Rochelle
Provedor de dados: 5
Autores: Dupuy, Christine; Pastoureaud, Annie; Ryckaert, Mireille; Sauriau, Pierre-guy; Montanie, Hélène.
To assess the in situ impact of oysters Crassostrea gigas on planktonic protist and bacteria communities and the potential contribution of protozoa to their food resource intake, the abundance and the diversity of protists and bacteria were followed in 2 Atlantic coastal ponds, with and without oysters. The protist biomass in such ponds was high, with a maximum in spring of 982 mug C l(-1) and a minimum in winter of 179 pg C l(-1). Whatever the season, the presence of oysters (20 m(-2) corresponding to an average of 23 mg dry weight m(-2)) induced a significant decrease in &gt;5 pm protist abundance. On the contrary, planktonic organisms &lt;5 pm, such as Chlorophyta flagellates and bacteria, developed similarly in both ponds. It can be assumed that such...
Tipo: Text
Palavras-chave: Trophic link; Bacteria; Protists; Microbial food web; Coastal pond; Food source; Oysters; Bivalve.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/2000/publication-822.pdf

Particle flux characterisation and sedimentation patterns of protistan plankton during the iron fertilisation experiment LOHAFEX in the Southern Ocean
Provedor de dados: 5
Autores: Ebersbach, Friederike; Assmy, Philipp; Martin, Patrick; Schulz, Isabelle; Wolzenburg, Sina; Noethig, Eva-maria.
The taxonomic composition and types of particles comprising the downward particle flux were examined during the mesoscale artificial iron fertilisation experiment LOHAFEX. The experiment was conducted in low-silicate waters of the Atlantic Sector of the Southern Ocean during austral summer (January-March 2009), and induced a bloom dominated by small flagellates. Downward particle flux was low throughout the experiment, and not enhanced by addition of iron; neutrally buoyant sediment traps contained mostly faecal pellets and faecal material apparently reprocessed by mesozooplankton. TEP fluxes were low, &lt;= 5 mg GX eq. m(-2) d(-1), and a few phytodetrital aggregates were found in the sediment traps. Only a few per cent of the POC flux was found in the...
Tipo: Text
Palavras-chave: Nano- and picoplankton; Export flux; Iron fertilisation; Protists; Sediment trap; Southern Ocean.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00290/40121/39348.pdf

Grazing of particle-associated bacteria-an elimination of the non-viable fraction
Provedor de dados: 58
Autores: Gonsalves,Maria-Judith; Fernandes,Sheryl Oliveira; Priya,Madasamy Lakshmi; LokaBharathi,Ponnapakkam Adikesavan.
Abstract Quantification of bacteria being grazed by microzooplankton is gaining importance since they serve as energy subsidies for higher trophic levels which consequently influence fish production. Hence, grazing pressure on viable and non-viable fraction of free and particle-associated bacteria in a tropical estuary controlled mainly by protist grazers was estimated using the seawater dilution technique. In vitro incubations over a period of 42 h showed that at the end of 24 h, growth coefficient (k) of particle-associated bacteria was 9 times higher at 0.546 than that of free forms. Further, ‘k’ value of viable cells on particles was double that of free forms at 0.016 and 0.007, respectively. While bacteria associated with particles were grazed...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bacteria; Ciliates; Grazing; Particle; Protists; Viable.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822017000100037