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| El-demerdash, Amr; Moriou, Celine; Toullec, Jordan; Besson, Marc; Soulet, Stephanie; Schmitt, Nelly; Petek, Sylvain; Lecchini, David; Debitus, Cecile; Al-mourabit, Ali. |
| Herein, we describe the isolation and spectroscopic identification of eight new tetrabrominated tyrosine alkaloids 2–9 from the Polynesian sponge Suberea ianthelliformis, along with known major compound psammaplysene D (1), N,N-dimethyldibromotyramine, 5-hydroxy xanthenuric acid, and xanthenuric acid. Cytotoxicity and acetylcholinesterase inhibition activities were evaluated for some of the isolated metabolites. They exhibited moderate antiproliferative activity against KB cancer cell lines, but psammaplysene D (1) displayed substantial cytotoxicity as well as acetylcholinesterase inhibition with IC50 values of 0.7 μM and 1.3 μM, respectively. |
| Tipo: Text |
Palavras-chave: Brominated tyrosine alkaloids; Suberea ianthelliformis; Cytotoxicity; Acetylcholinesterase inhibition. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00439/55076/56506.pdf |
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| Toullec, Jordan; Vincent, Dorothée; Frohn, Laura; Miner, Philippe; Le Goff, Manon; Devesa, Jérémy; Moriceau, Brivaela. |
| In marine ecosystems, carbon export is driven by particle flux which is modulated by aggregation, remineralization, and grazing processes. Zooplankton contribute to the sinking flux through the egestion of fast sinking fecal pellets but may also attenuate the flux by tearing apart phytoplankton aggregates into small pieces through swimming activity or direct ingestion. Freely suspended cells, artificial monospecific aggregates from two different diatom species (Chaetoceros neogracile and Skeletonema marinoi) and natural aggregates of Melosira sp. were independently incubated with five different copepod species (Acartia clausi, Temora longicornis, Calanus helgolandicus, Euterpina acutifrons, and Calanus hyperboreus). During the grazing experiments initiated... |
| Tipo: Text |
Palavras-chave: Diatom aggregate; Grazing experiment; Copepod; Sinking velocity; Particle dynamics. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00594/70605/68799.pdf |
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| González-fernández, Carmen; Toullec, Jordan; Lambert, Christophe; Le Goïc, Nelly; Seoane, Marta; Moriceau, Brivaela; Huvet, Arnaud; Berchel, Mathieu; Vincent, Dorothée; Courcot, Lucie; Soudant, Philippe; Paul-pont, Ika. |
| The potential presence of nanoplastics (NP) in aquatic environments represents a growing concern regarding their possible effects on aquatic organisms. The objective of this study was to assess the impact of polystyrene (PS) amino-modified particles (50 nm PSNH2) on the cellular and metabolic responses of the diatom Chaetoceros neogracile cultures at two essential phases of the growth cycle, i.e. exponential (division) and stationary (storage) phases. Both cultures were exposed for 4 days to low (0.05 μg mL−1) and high (5 μg mL−1) concentrations of PS-NH2. Exposure to NP impaired more drastically the major cellular and physiological parameters during exponential phase than during the stationary phase. Only an increase in ROS production was observed at... |
| Tipo: Text |
Palavras-chave: Nanoplastics; Diatoms; Physiology; Transparent exopolymer particles. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00491/60235/63627.pdf |
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| Mai, Tepoerau; Toullec, Jordan; Van Wynsberge, Simon; Besson, Marc; Soulet, Stephanie; Petek, Sylvain; Aliotti, Emmanuelle; Ekins, Merrick; Hall, Kathryn; Erpenbeck, Dirk; Lecchini, David; Beniddir, Mehdi A.; Saulnier, Denis; Debitus, Cecile. |
| Marine natural products isolated from the sponge Fascaplysinopsis cf reticulata, in French Polynesia, were investigated as an alternative to antibiotics to control pathogens in aquaculture. The overuse of antibiotics in aquaculture is largely considered to be an environmental pollution, because it supports the transfer of antibiotic resistance genes within the aquatic environment. One environmentally friendly alternative to antibiotics is the use of quorum sensing inhibitors (QSIs). Quorum sensing (QS) is a regulatory mechanism in bacteria which control virulence factors through the secretion of autoinducers (AIs), such as acyl-homoserine lactone (AHL) in gram-negative bacteria. Vibrio harveyi QS is controlled through three parallel pathways: HAI-1, AI-2,... |
| Tipo: Text |
Palavras-chave: Porifera; Marine natural products; Quorum sensing inhibitors; Antibiotic; Fascaplysinopsis cf reticulata. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00598/71052/69366.pdf |
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| Toullec, Jordan; Moriceau, Brivaela. |
| Diatom production is mainly supported by the dissolution of biogenic silica (bSiO(2)) within the first 200 m of the water column. The upper oceanic layer is enriched in dissolved and/or colloidal organic matter, such as exopolymeric polysaccharides (EPS) and transparent exopolymeric particles (TEP) excreted by phytoplankton in large amounts, especially at the end of a bloom. In this study we explored for the first time the direct influence of TEP-enriched diatom excretions on bSiO(2) dissolution. Twelve dissolution experiments on fresh and fossil diatom frustules were carried out on seawater containing different concentrations of TEP extracted from diatom cultures. Fresh diatom frustules were cleaned from the organic matter by low ash temperature, and... |
| Tipo: Text |
Palavras-chave: Exopolysaccharide; Diatom excretion; Diatomite; Chaetoceros muelleri; Biogenic silica; BSiO(2) dissolution; TEP. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00616/72795/72270.pdf |
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