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| Registros recuperados: 30 | |
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| Triki, Habiba Zmerli; Laabir, Mohamed; Moeller, Peter; Chomerat, Nicolas; Daly-yahia, Ons Kefi. |
| The dinoflagellate Alexandrium pseudogonyaulax is widely distributed around the world including the Mediterranean waters. The objectives of this study were to determine the morphology and phylogenic affiliation of A. pseudogonyaulax strain isolated from Bizerte Lagoon (Mediterranean waters, Tunisia) and investigate its toxicity. Molecular analyses confirmed the morphological identification of the isolated strain (APBZ12) as A. pseudogonyaulax. Moreover, it showed that it is 100% identical with strains of this species found in New Zealand, Japan, China and North Sea (Norway and Denmark) suggesting that this species is cosmopolitan. Until now, no toxin studies have been conducted on fully characterized (morphologically and molecularly) A. pseudogonyaulax.... |
| Tipo: Text |
Palavras-chave: Alexandrium pseudogonyaulax; Goniodomin A; Mediterranean sea; Morphology; Phylogeny. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00302/41356/40548.pdf |
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| Nezan, Elisabeth; Bilien, Gwenael; Boulben, Sylviane; Mertens, Kenneth; Chomerat, Nicolas. |
| A new marine raphid diatom, Plagiolemma distortum Nézan, sp. nov. is described from plankton samples from the Atlantic Ocean, south Brittany (north-western France), where it was regularly observed, but never in high abundances. Cells have an unusual and complex shape under light microscopy (LM) depending on their position and orientation. The two valves are highly vaulted and narrow in width (transapical axis). Cells contain four complexly lobed plastids and a variable number of refractive granules without particular localization. In addition, capsules containing motile cells were observed. Ultrastructural details of the frustules were investigated using scanning electron microscopy (SEM). The girdle bands are simple. Each valve possesses a sigmoid raphe... |
| Tipo: Text |
Palavras-chave: Capsules; Habitat; Molecular phylogeny; Plastids; Raphid diatom; Video. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00441/55235/56797.pdf |
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| Amzil, Zouher; Sibat, Manoella; Chomerat, Nicolas; Grossel, Hubert; Marco-miralles, Francoise; Lemee, Rodolphe; Nezan, Elisabeth; Sechet, Veronique. |
| Dinoflagellates of the genus Ostreopsis are known to cause (often fatal) food poisoning in tropical coastal areas following the accumulation of palytoxin (PLTX) and/or its analogues (PLTX group) in crabs, sea urchins or fish. Ostreopsis spp. occurrence is presently increasing in the northern to north western Mediterranean Sea (Italy, Spain, Greece and France), probably in response to climate change. In France, Ostreopsis. cf. ovata has been associated with toxic events during summer 2006, at Morgiret, off the coast of Marseille, and a specific monitoring has been designed and implemented since 2007. Results from 2008 and 2009 showed that there is a real danger of human poisoning, as these demonstrated bioaccumulation of the PLTX group (PLTX and ovatoxin-a)... |
| Tipo: Text |
Palavras-chave: Ostreopsis cf. ovata; Palytoxin; Ovatoxin-a; LC-MS/MS; Seafood. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00071/18230/15799.pdf |
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| Van Nieuwenhove, Nicolas; Potvin, Eric; Heikkila, Maija; Pospelova, Vera; Mertens, Kenneth; Masure, Edwige; Kucharska, Malgorzata; Yang, Eun Jin; Chomerat, Nicolas; Zajaczkowski, Marek. |
| We restudied the morphological complex comprising the cyst-based species Spiniferites elongatus/Spiniferites frigidus/Rottnestia amphicavata. We reviewed existing studies, and acquired new morphometric measurements of recent cysts from across the Northern Hemisphere, scanning electron microscopy (SEM) observations of cysts from Barents Sea surface sediments, and genetic analyses of cysts from the Beaufort Sea. The measurements suggest that populations and morphospecies cannot be distinguished based on morphometric criteria. Furthermore, sequential sediment trap samples from Hudson Bay reveal that morphological variation can occur at the same location over a few weeks, arguing against a uniform morphological response to environmental parameters. The SEM... |
| Tipo: Text |
Palavras-chave: Single-cell PCR; Spiniferites ellipsoideus; Spiniferites frigidus; Rottnestia amphicavata; Morphologic variability; Taxonomy. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00471/58305/60846.pdf |
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| Saburova, Maria; Chomerat, Nicolas. |
| A small Prorocentrum species was found during a pilot taxonomic survey of marine benthic dinoflagellates in the northwestern Arabian Sea, Oman. Based on the study of cells from natural samples and laboratory cultures using light and scanning electron microscopy, this taxon is attributed to the little-known Prorocentrum sipadanense, recorded so far only from East Malaysia. The description of this species has been emended to include details of internal cell structure, composition of its periflagellar area and intraspecific variability in size, shape and pore pattern. Round to oval or ovoid cells of P. sipadanese are surrounded by a prominent marginal ridge and are 17.9–23.9 µm long and 15.0–19.8 µm wide, with a foveate to reticulate thecal plate surface and... |
| Tipo: Text |
Palavras-chave: Arabian Sea; Benthic dinoflagellates; Molecular phylogeny; Morphology; Oman; Prorocentrum sipadanense; Taxonomy. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00319/42990/42560.pdf |
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| Coute, Alain; Perrette, Catherine; Chomerat, Nicolas. |
| Clipperton Island is a small French coral atoll in the eastern Pacific Ocean, which has been rarely investigated because of its remote location and difficult access. There is little scientific information on this ecosystem and only a few microalgae have been reported from the lagoon. To date, only one dinoflagellate taxon, Peridiniopsis cristata, is known to inhabit the lagoon. During an expedition in 2005 to study the lagoon and the surrounding oceanic waters of Clipperton Island, a further investigation of the lagoon phytoplankton was undertaken. In addition to P. cristata, which was still abundant in the upper water layer, two other thecate dinoflagellates were recorded. One dinoflagellate was identified as Durinskia baltica, while the other had the... |
| Tipo: Text |
Palavras-chave: Dinoflagellates; Lagoon; Morphology; Phytoplankton; Taxonomy. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00070/18086/15633.pdf |
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| Lemonnier, Hugues; Lantoine, Francois; Courties, Claude; Guillebault, Delphine; Nezan, Elisabeth; Chomerat, Nicolas; Escoubeyrou, Karine; Galinie, Christian; Blockmans, Bernard; Laugier, Thierry. |
| Tropical shrimp aquaculture systems in New Caledonia regularly face major crises resulting from outbreaks of Vibrio infections. Ponds are highly dynamic and challenging environments and display a wide range of trophic conditions. In farms affected by vibriosis, phytoplankton biomass and composition are highly variable. These conditions may promote the development of harmful algae increasing shrimp susceptibility to bacterial infections. Phytoplankton compartment before and during mortality outbreaks was monitored at a shrimp farm that has been regularly and highly impacted by these diseases. Combining information from flow cytometry, microscopy, pigment and phylogenetic analysis, the presence of Picocyanobacteria, Prasinophyceae and Diatomophyceae were... |
| Tipo: Text |
Palavras-chave: Tropical aquaculture pond; Litopenaeus stylirostris; Vibriosis; Eutrophication; Phytoplankton; Harmful algae. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00343/45411/44986.pdf |
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| Neaud-masson, Nadine; Brun, Melanie; Chomerat, Nicolas. |
| La détermination des espèces phytoplanctoniques et l’estimation de leur abondance dans le cadre du Réseau d’observation et de surveillance du Phytoplancton et de l’Hydrologie, mis en œuvre par l’Ifremer (REPHY) s’appuie en 2016 sur 25 analystes, répartis dans 9 laboratoires sur 12 sites. Neuf d’entre eux ont été inscrits à titre individuel en 2016 pour participer à l'exercice d’inter-comparaison international (IPI) organisé tous les ans par le Marine Institute Phytoplankton unit de Galway (Ireland). Les échantillons envoyés aux analystes concernés ont été utilisés pour évaluer aussi les compétences des analystes non-inscrits à l’IPI, mais réalisant également des analyses de phytoplancton dans ces mêmes laboratoires pour le REPHY. Au total, 23 analystes... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00388/49923/50497.pdf |
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| Saburova, Maria; Chomerat, Nicolas. |
| A new photosynthetic, sand-dwelling marine dinoflagellate, Ailadinium reticulatum gen. et sp. nov., is described from the Jordanian coast in the Gulf of Aqaba, northern Red Sea, based on detailed morphological and molecular data. A. reticulatum is a large (53–61 μm long and 38–48 μm wide), dorsoventrally compressed species, with the epitheca smaller than the hypotheca. The theca of this new species is thick and peculiarly ornamented with round to polygonal depressions forming a foveate-reticulate thecal surface structure. The Kofoidian thecal tabulation is APC (Po, cp), 4′, 2a, 6′′, 6c, 4s, 6′′′, 1p, 1′′′′ or alternatively it can be interpreted as APC, 4′, 2a, 6′′, 6c, 4s, 6′′′, 2′′′′. The plate pattern of A. reticulatum is noticeably different from... |
| Tipo: Text |
Palavras-chave: Benthic dinoflagellates; Dinophyceae; Gulf of Aqaba; Jordan; LSU rDNA; Molecular phylogeny; Morphology; Red Sea; SSU rDNA; Taxonomy. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00226/33678/38183.pdf |
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| Le Gac, Mickael; Metegnier, Gabriel; Chomerat, Nicolas; Malestroit, Pascale; Quere, Julien; Bouchez, Olivier; Siano, Raffaele; Destombe, Christophe; Guillou, Laure; Chapelle, Annie. |
| Understanding divergence in the highly dispersive and seemingly homogeneous pelagic environment for organisms living as free drifters in the water column remains a challenge. Here, we analyzed the transcriptome wide mRNA sequences, as well as the morphology of 18 strains of Alexandrium minutum, a dinoflagellate responsible for Harmful Algal Blooms worldwide, to investigate the functional bases of a divergence event. Analysis of the joint site frequency spectrum (JSFS) pointed toward an ancestral divergence in complete isolations followed by a secondary contact resulting in gene flow between the two diverging groups, but heterogeneous across sites. The sites displaying fixed SNPs were associated with a highly restricted gene flow and a strong... |
| Tipo: Text |
Palavras-chave: Dinoflagellates; Harmful algal blooms; Populations Genomics; Pseudocryptic species; Speciation. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00347/45857/45529.pdf |
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| Lassus, Patrick; Chomerat, Nicolas; Hess, Philipp; Nezan, Elisabeth. |
| This book updates available international databases on toxic and harmful species of phytoplankton and micro-phytobenthos. It lists regional occurrences at world-wide scale: localities, cell densities, toxicity levels in contaminated animals, human and animal poisoning, isolation of identified active molecules and toxins, documentary sources. Finally, this book addresses the geographic distributions of phycotoxin-producers from recent data. The objective is to analyze the evolution of toxic and harmful episodes over the past 30 years to identify trends, and to introduce a discussion on the reality of a time-dependent increase in the number of known species and toxins. |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00379/49054/49508.pdf |
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| Mertens, Kenneth; Chomerat, Nicolas; Nezan, Elisabeth; Bruneau, Audrey; Le Bec, Claude. |
| Les inspections vétérinaires de la Commission Européenne ayant signifié à la France son constat d'une absence de réserau de surveillance sur les claires ostréicoles, la DGAL a mandaté l'Ifremer afin de réaliser un premier diagnostic sur le phytoplancton. Cette commande de la DGAL place l'Ifremer LERBO comme prestataire de service et spécialiste des micro-algues. Les claires ostréicoles étant hors du domaine public maritime, une concertation avec le Comité Régional de la Conchyliculture de Poitou-Charentes, la DGAL et la DDTM 17 en juin 2018 a permis de proposer six claires, réparties entre l'île de Ré et l'île d'Oléron et pouvant être échantillonnées. L'objectif est de faire un état des lieux de la présence ou de l'absence de cellules de phytoplancton... |
| Tipo: Text |
Palavras-chave: Charentes; Claire; Phytoplancton; Micro-algue; Toxine. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00486/59731/62828.pdf |
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| Chomerat, Nicolas; Garnier, Robert; Bertrand, Céline; Cazaubon, Arlette. |
| The Bolmon lagoon (South of France) is an oligo-mesohaline coastal lagoon that has undergone intense eutrophication in the past decades, resulting from a strong concentration of human activities in its drainage basin. Consequently, it exhibits some characteristics typical of an advanced trophic state; namely, the disappearance of submerged vegetation, the permanently intense phytoplankton growth and the recurrence of cyanoprokaryote blooms. As cyanoprokaryote dominance in south-temperate saline lagoons is little reported, we carried out this study in order to understand the seasonal variations in the phytoplankton composition and biomass, and to analyse the influence of environmental parameters such as salinity, nutrients and climate on the seasonal... |
| Tipo: Text |
Palavras-chave: Turbid state; Pseudanabaena limnetica; Planktothrix agardhii; Phytoplankton; Mediterranean area; Cyanoprokaryotes; Ecology; Lagoon; Brackish water. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2593.pdf |
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| Nezan, Elisabeth; Chomerat, Nicolas. |
| A new species of the genus Fragilidium, F. duplocampanaeforme sp. nov., is described from examinations by LM and SEM. This species has been recorded in summer on the French Atlantic coast, over a number of years. It was never abundant in the plankton and was very often associated with Fragilidium subglobosum, Pyrophacus horologium and also with toxigenic species of the genera Alexandrium and Dinophysis. Phagotrophy of F. duplocampanaeforme on Dinophysis prey is shown, and sexual reproduction is suggested by the observation of gamete-like small forms. The size and the peculiar shape of its cells do not correspond to any known taxon, but the plate arrangement fits the genus Fragilidium. The plate formula is Po, Pc, 4', 8 '', 10c, 6s?, 7"', 2 '''', lp. A... |
| Tipo: Text |
Palavras-chave: Taxonomy; Phagotrophy; Fragilidium duplocampanaeforme sp nov.; Fragilidium; Dinophyceae; Atlantic ocean. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6233.pdf |
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| Gurdebeke, Pieter R.; Mertens, Kenneth; Bogus, Kara; Marret, Fabienne; Chomerat, Nicolas; Vrielinck, Henk; Louwye, Stephen. |
| The genus Spiniferites currently encompasses 142 dinoflagellate cyst species. Some Spiniferites species are difficult to identify because of an incomplete or doubtful description, and/or substandard iconography. This study re-describes and re-illustrates the Spiniferites holotypes first described by Reid in 1974 Reid PC. 1974. Gonyaulacacean dinoflagellate cysts from the British Isles. Nova Hedwigia. 25:579–637. [Google Scholar]. It also discusses topotype material from surface sediments recovered from British estuaries, and attempts to provide further constraints on the classification of species in this genus using the geochemical characterization of their cyst walls. Reid described four new Spiniferites species: Spiniferites belerius, Spiniferites... |
| Tipo: Text |
Palavras-chave: Dinoflagellate cyst; Redescription; Taxonomy; Geochemistry; Cyst wall composition; FTIR; Dinosporin. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00471/58306/60847.pdf |
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| Brissard, Charline; Herrenknecht, Christine; Sechet, Veronique; Herve, Fabienne; Pisapia, Francesco; Harcouet, Jocelyn; Lemee, Rodolphe; Chomerat, Nicolas; Hess, Philipp; Amzil, Zouher. |
| Ostreopsis cf. ovata produces palytoxin analogues including ovatoxins (OVTXs) and a putative palytoxin (p-PLTX), which can accumulate in marine organisms and may possibly lead to food intoxication. However, purified ovatoxins are not widely available and their toxicities are still unknown. The aim of this study was to improve understanding of the ecophysiology of Ostreopsis cf. ovata and its toxin production as well as to optimize the purification process for ovatoxin. During Ostreopsis blooms in 2011 and 2012 in Villefranche-sur-Mer (France, NW Mediterranean Sea), microalgae epiphytic cells and marine organisms were collected and analyzed both by LC-MS/MS and hemolysis assay. Results obtained with these two methods were comparable, suggesting ovatoxins... |
| Tipo: Text |
Palavras-chave: Ostreopsis cf. ovata; Palytoxin & ovatoxins; Culture; Seafood contamination; LC-MS/MS; Hemolysis assay; Mediterranean Sea. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00199/31025/29428.pdf |
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| Luo, Zhaohe; Lim, Zhen Fei; Mertens, Kenneth; Gurdebeke, Pieter; Bogus, Kara; Carbonell-moore, Maria Consuelo; Vrielinck, Henk; Leaw, Chui Pin; Lim, Po Teen; Chomerat, Nicolas; Li, Xintian; Gu, Haifeng. |
| The dinoflagellate genus Bysmatrum encompasses five epibenthic or tide-pool species and has been characterized by separated anterior intercalary plates. In the present study, we obtained six strains of Bysmatrum from the South China Sea and French Atlantic coast by isolating single cells/cysts from plankton and sediment samples. All strains were examined with light microscopy and scanning electron microscopy. Based on morphological observations, three strains were identified as Bysmatrum subsalsum, characterized by the elongated and rectangular first and a hexagonal second anterior intercalary plate. They differ from each other in the number of sulcal lists and the configuration of the first anterior intercalary plate. One strain was identified as... |
| Tipo: Text |
Palavras-chave: Benthic dinoflagellate; Biogeography; Bysmatrum granulosum; Bysmatrum gregarium; Bysmatrum subsalsum; Eyespot; Molecular phylogeny. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00450/56188/57872.pdf |
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| Chomerat, Nicolas; Bilien, Gwenael. |
| A new benthic phototrophic dinoflagellate is described from sediments of a tropical marine cove at Martinique Island and its micromorphology is studied by means of light and electron microscopy. The cell contains small golden-brown chloroplasts and the oval nucleus is posterior. It is laterally compressed, almost circular in shape when viewed laterally. It consists of a small epitheca tilted toward the right lateral side and a larger hypotheca. In the left view, the cingulum is more anterior and the epitheca is reduced. The cingulum is displaced and left-handed. This organism is peculiar in having no apical pore and its thecal plate arrangement is 2 ' 1a 7 '' 5c 3s 5 ''' 1 ''''. The plates are smooth with small groups of pores scattered on their surface.... |
| Tipo: Text |
Palavras-chave: Caribbean; Benthic; Dinophyceae; SEM; Phylogeny; Morphology; Taxonomy; Martinique; RDNA. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00195/30622/29458.pdf |
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| Registros recuperados: 30 | |
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