Publications by authors named "Gaetane Wielgosz-Collin"

Microalgae provide valuable bio-components with economic and environmental benefits. The monitoring of microalgal production is mostly performed using different sensors and analytical methods that, although very powerful, are limited to qualified users. This study proposes an automated Raman spectroscopy-based sensor for the online monitoring of microalgal production.

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Sterols are the main components of the fungal membrane. Their study can be used to describe the chemical biodiversity among the strains and species or to work on antifungal treatment. Those molecules can be analyzed by gas chromatography coupled with mass spectrometry (GC-MS) as free molecules or after derivation as acetate or trimethylsilyl ether (TMSi).

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Microalgal biotechnology has gained considerable importance in recent decades. Applications range from simple biomass production for food and animal feed to valuable products for fuel, pharmaceuticals, health, biomolecules and materials relevant to nanotechnology. There are few reports of the exploration of wider microalgae biodiversity in the literature on high value microalgal compounds, however, because it is believed that there is little to be gained in terms of biomass productivity by examining new strains.

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The most common sterol in fungi is ergosterol, which has frequently been investigated in human pathogenic fungal strains. This sterol, and others isolated from fungal strains, has also demonstrated cytotoxicity against cancer cell lines and antimicrobial activities. Marine fungi can produce high amounts of bioactive compounds.

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Diatoms adapt to changing environmental conditions in very efficient ways. Among the mechanisms that can be activated, the reorientation of carbon metabolism is crucial because it allows the storage of energy into energy-dense molecules, typically lipids. Beside their roles in physiology, lipids are commercially interesting compounds.

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In this study, we investigated the responses of cells acclimated to 300 µmol m s photon flux density to an increase (1000 µmol m s) or decrease (30 µmol m s) in photon flux densities. The light shift occurred abruptly after 5 days of growth and the acclimation to new conditions was followed during the next 6 days at the physiological and molecular levels. The molecular data reflect a rearrangement of carbon metabolism towards the production of phosphoenolpyruvic acid (PEP) and/or pyruvate.

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Economic exploitation is one means to offset the cost of controlling invasive species, such as the introduced Pacific oyster (Crassostrea gigas Thunberg) on the French Atlantic coast. Total lipid and phospholipid (PL) fatty acids (FAs) and sterols were examined in an invasive population of C. gigas in Bourgneuf Bay, France, over four successive seasons, with a view to identify possible sources of exploitable substances.

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A marine-derived strain of Clonostachys rosea isolated from sediments of the river Loire estuary (France) was investigated for its high lipid production. The fungal strain was grown on six different culture media to explore lipid production changes. An original branched conjugated fatty acid, mainly present in triglycerides and mostly produced when grown on DCA (23% of total fatty acid composition).

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The invasive mollusk Crepidula fornicata, occurring in large amounts in bays along the French Northeastern Atlantic coasts, may have huge environmental effects in highly productive ecosystems where shellfish are exploited. The present study aims at determining the potential economic value of this marine species in terms of exploitable substances with high added value. Lipid content and phospholipid (PL) composition of this mollusk collected on the Bourgneuf Bay were studied through four seasons.

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The marine sponge, Axinyssa djiferi, collected on mangrove tree roots in Senegal, was investigated for glycolipids. A mixture containing new glycosphingolipids, named axidjiferoside-A, -B and -C, accounted for 0.07% of sponge biomass (dry weight) and for 2.

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Phospholipids (PL) and glycolipids (GL) FA in the edible Rhodophyta Grateloupia turuturu, from Brittany, France, were investigated over four seasons. The major lipid class was GL in all seasons (around 45 %). More than 80 FA occurred in polar lipids, with chains from C12 to C26, identified as methyl esters and N-acyl pyrrolidides by gas chromatography-mass spectrometry (GC-MS).

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Glycolipids of Myrmekioderma sponges contain Myrmekiosides, a new family of glycolipids with a unique structure of mono-O-alkyl-diglycosylglycerols. This report deals with the identification and biological activity of the new Myrmekioside E from Myrmekioderma dendyi. Its structure has been elucidated from spectroscopic data and chemical degradation studies.

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The starfish Narcissia canariensis harvested from the coasts off Dakar, Senegal, was investigated for glycolipids (GL). This report deals with the isolation, characterization and biological activity of a fraction F13-3 separated from the GL mixture and selected according to its ability to inhibit KB cell proliferation after 72 hours of treatment. Firstly, a GL mixture F13 was obtained that accounted for 1.

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Two tunicates, Eudistoma sp. and Leptoclinides uniorbis, collected from the tropical waters off Djibouti were investigated for lipids and phospholipid (PL) fatty acids. PL accounted for 38.

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The phospholipid fatty acid composition of the North-East Atlantic sponge Polymastia penicillus (South Brittany, France) was investigated. Sixty fatty acids (FA) were identified as methyl esters (FAME) and N-acyl pyrrolidides (NAP) by gas chromatography-mass spectrometry (GC/MS), including eight Delta5,9 unsaturated FA and three long-chain 2-hydroxylated FA. The major phospholipid FA were palmitic (14.

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An unusual sterolic mixture (82.3% of 24-isopropylated sterols) and its major component, 24-isopropylcholesterol, isolated from a marine sponge, Ciocalypta sp. (Halichondriidae), reduce cholesterol uptake, basolateral secretion and ACAT-2 mRNA expression and increase the expression of ABCA1 mRNA in Caco-2 cells.

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The exceptional ability of marine sponges to adapt to often drastic changes of their environments could be due to special structural features in cell membranes, including firstly phospholipids (PL). Thus, PL class composition was investigated in marine sponges (22 species from 19 genera to 15 families) originating from various locations (East Atlantic, North Atlantic, South-West Pacific, Mediterranean Sea, Red Sea, Arabian-Persian Gulf). The quantitative determination of PL class composition was obtained by high-performance thin-layer chromatography (HPTLC) with scanning densitometry of the different spots.

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A marine strain of Trichoderma longibrachiatum isolated from blue mussels (Mytilus edulis) was investigated for short peptaibol production. Various 11-residue peptaibols, obtained as microheterogenous mixtures after a chromatographic fractionation, were identified by positive mass spectrometry fragmentation (ESI-IT-MS(n), CID-MS(n) and GC/EI-MS). Thirty sequences were identified, which is the largest number of analogous sequences so far observed at once.

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The synthesis and pharmacological evaluation of analogues of PD 160170, a neuropeptide Y1 (NPY) receptor antagonist are reported. Phamacomodulation of this 8-amino-5-nitro-6-phenylsulfonylquinoline was carried out by replacing the sulfone moiety by oxygen. The corresponding ethers 11-16 were obtained by nucleophilic substitution of 8-acetamido-6-chloro-5-nitroquinoline 4 with phenols, followed by acidic hydrolysis of the intermediary amides 5-10.

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