12 results on '"Derenne, Sylvie"'
Search Results
2. Evolution of lipid abundance and molecular composition during the podzolisation of laterites in the upper Amazon basin
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Bardy, Marion, Derenne, Sylvie, and Fritsch, Emmanuel
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- 2009
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3. Variation in lipid relative abundance and composition among different particle size fractions of a forest soil
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Quenea, Katell, Derenne, Sylvie, Largeau, Claude, Rumpel, Cornélia, and Mariotti, André
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LIPIDS , *BIOMOLECULES , *HUMUS , *FOREST microclimatology - Abstract
Most studies of soil organic matter are on humic substances although a substantial contribution of lipids is generally noted for soils. Moreover, soil lipids were shown to have a relatively high resistance to biodegradation. Thus, they could provide information on organic matter sources and diagenetic processes. Soil organic matter is highly heterogeneous and different dynamic pools are in evidenced. However the links between these pools and molecular structure have not yet been established. Soil lipids were investigated in three particle-size fractions of a forest soil. Lipids were shown to be preferentially located in the finest fraction. GC-MS analysis of free lipids has revealed different main sources depending on the particle-size fraction and differential degradation. Furthermore, the results obtained for the free lipids on the one hand, and the saponified lipids on the other hand, have indicated that different preservation mechanisms for lipids occur in this soil. [Copyright &y& Elsevier]
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- 2004
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4. Influence of environmental parameters on the distribution of bacterial lipids in soils from the French Alps: Implications for paleo-reconstructions.
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Véquaud, Pierre, Derenne, Sylvie, Anquetil, Christelle, Collin, Sylvie, Poulenard, Jérôme, Sabatier, Pierre, and Huguet, Arnaud
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LIPIDS , *SOILS , *SOIL classification , *SOIL moisture , *ATMOSPHERIC temperature , *MOUNTAIN soils - Abstract
• 3-OH FAs and brGDGTs analyzed in soils from an altitudinal transect in the French Alps. • Investigation of the environmental factors controlling the distribution of bacterial lipids. • Influence of soil traits predominant over MAAT. • Statistical identification of the individual bacterial lipids influenced by MAAT/pH required. • Development of local calibrations with MAAT and pH based on such identification. Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are a family of bacterial lipids widely used for temperature and pH reconstructions in terrestrial settings. 3-hydroxy fatty acids (3-OH FAs) with 10–18 carbon atoms, produced by Gram-negative bacteria, have been recently proposed as independent and complementary proxies of temperature and pH in terrestrial environments. Nevertheless, the correlations between mean annual air temperature (MAAT)/pH and bacterial lipid (brGDGTs/3-OH FAs) distributions show a large degree of scatter, as the relative abundance of these lipids is influenced by factors other than temperature and pH. A full understanding of the environmental parameters influencing bacterial lipid distribution in soils is required to increase the reliability of the temperature and pH proxies based on these compounds in terrestrial environments. The aim of this work was to determine and quantify the cumulative effect of environmental parameters on the distribution of both brGDGTs and 3-OH FAs along a well-documented composite altitudinal transect in the French Alps (234–2748 m). Redundancy analysis revealed that the influence of local parameters (pH and to a lesser extent, soil moisture and grain size, related to vegetation and soil types) on brGDGT and 3-OH FA distributions amounted to 48.1% and 26.1%, respectively, and was predominant over MAAT. This likely explained the weak or lack of relationships between MAAT and brGDGT-/3-OH FA-based indices in this region. The identification of lipids whose fractional abundance is correlated with MAAT or pH allowed the development of local calibrations with MAAT/pH applicable in the French Alps, which are representative of highly contrasted microenvironments, reflecting different types of soil and vegetation. The present study highlighted the importance of constraining the environmental factors affecting the distribution of 3-OH FAs and brGDGTs in terrestrial settings prior to any paleoenvironmental reconstruction. Such an approach should be reproduced in other sites, where local factors could also strongly influence the bacterial lipid distribution. [ABSTRACT FROM AUTHOR]
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- 2021
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5. Root-associated branched tetraether source microorganisms may reduce estimated paleotemperatures in subsoil.
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Huguet, Arnaud, Gocke, Martina, Derenne, Sylvie, Fosse, Céline, and Wiesenberg, Guido L.B.
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SUBSOILS , *GLYCERIN , *ETHERS , *PLANT roots , *LIPIDS , *MOLECULAR weights , *SOIL microbiology ,THERMAL properties of soils - Abstract
Abstract: Branched glycerol dialkyl glycerol tetraethers (GDGTs) are complex lipids of high molecular weight, recently discovered in soils and suggested to be produced by still unknown bacteria. The relative distribution of these compounds was shown to depend on environmental parameters, mainly temperature and pH. Over the last years, an increasing number of studies have focused on the application of branched GDGTs as paleoclimate proxies, but only a few were performed in terrestrial archives. In this study, branched GDGTs were analyzed in calcified and non-calcified living and dead roots, in surrounding soil and sediment and in reference material distant from the roots. Samples were mainly collected from subsoil of two forest sites near Sopron (Hungary), where soils developed on fluvial sand and loess deposits, respectively. Branched GDGTs were more abundant in root samples and/or surrounding rhizosphere compared to reference material, suggesting that branched GDGT source microorganisms are closely associated with the root surface. In subsoil, the GDGT-based temperature estimates from former roots and surrounding sediments were mainly lower than those from reference material in both loess and sand profiles. This is likely due to the post-sedimentary incorporation of branched GDGTs deriving from microorganisms that fed on root organic matter in terrestrial sediments. In contrast, branched GDGT-derived temperatures do not seem to be influenced by the presence of roots in topsoil, which may be related to the much higher density of recent roots in topsoil than in subsoil. This argues for a more homogeneous distribution of root-associated microorganisms especially in densely rooted topsoils. In addition, we show that sample pre-treatment may have an effect on the abundance and distribution of branched GDGTs. Indeed, washing root samples with ultrapure water might lead to a decrease in GDGT abundance and an increase in temperature estimates, likely due to the removal of particles adhering to the root surface. Decarbonatization of root and surrounding sediment had only a limited effect on GDGT-derived parameters. Taken together, these results suggest that paleoenvironmental data obtained from branched GDGTs in terrestrial archives might depend on the way the samples were collected and prepared and should be interpreted with caution, especially in loess-paleosol sequences where the frequency of calcified roots can be locally very high. [Copyright &y& Elsevier]
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- 2013
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6. Archaeal and bacterial tetraether lipids in tropical ponds with contrasting salinity (Guadeloupe, French West Indies): Implications for tetraether-based environmental proxies.
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Huguet, Arnaud, Grossi, Vincent, Belmahdi, Imène, Fosse, Céline, and Derenne, Sylvie
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ARCHAEBACTERIA , *LIPIDS , *PONDS , *SALINITY - Abstract
The occurrence and distribution of archaeal and bacterial glycerol dialkyl glycerol tetraether lipids (GDGTs) in continental saline environments have been rarely investigated. Here, the abundance and distribution of archaeal isoprenoid GDGTs (iGDGTs) and archaeol, and of bacterial branched GDGTs (brGDGTs) in four tropical water ponds of contrasting salinity in two islands from the French West Indies, Grande-Terre and La Désirade, have been determined. The sedimentary distribution of the GDGTs strongly differed between the two islands. Caldarchaeol was largely predominant among iGDGTs in the (hyper)saline ponds from Grande-Terre, suggesting a substantial contribution of iGDGTs derived from methanogenic Archaea. In contrast, both caldarchaeol and crenarchaeol were present in high relative abundance in the low salinity ponds from La Désirade, suggesting that iGDGTs were derived from mixed archaeal communities. In addition, the relative proportion of the most methylated brGDGTs was much higher in Grande-Terre ponds than in La Désirade ponds. The applicability of different proxies based on GDGTs and archaeol was tested for these specific environments. The relative abundance of archaeol vs. caldarchaeol (ACE index) was comparable for the four ponds, independent of salinity, showing that the ACE index might not necessarily track salinity change. Moreover, the relative proportion of caldarchaeol vs. total iGDGTs was unexpectedly observed to increase with salinity, suggesting production of this compound by halophilic Archaea. The supposed high abundance of methanogenic Archaea in Grande-Terre ponds prevented the application of TEX 86 as a temperature proxy, whereas TEX 86 could be successfully used for local temperature reconstruction in La Désirade ponds. BrGDGTs seem to be produced predominantly in situ (water column and/or sediment) in hypersaline ponds from Grande-Terre, but in La Désirade ponds likely result from a mixture of soil and aquatic sources. In Grande-Terre ponds, brGDGT-derived temperature estimates generated using either soil or lacustrine calibrations were much lower than expected. The mismatch between expected and estimated temperature might be explained by the presence of halophilic microbial communities producing specific brGDGT distributions in the saline ponds from Grande-Terre. The study shows that the sources of brGDGTs, iGDGTs and archaeol (i) may strongly differ in aquatic environments of varying salinity, even at a regional scale, and (ii) have to be constrained before tetraether-derived proxies in such settings can be confidently applied. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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7. Characterisation of organic matter from organo-mineral complexes in an Andosol from Reunion Island
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de Junet, Alexis, Basile-Doelsch, Isabelle, Borschneck, Daniel, Masion, Armand, Legros, Samuel, Marol, Christine, Balesdent, Jérôme, Templier, Joëlle, and Derenne, Sylvie
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ANDOSOLS , *HUMUS , *SEPARATION (Technology) , *GAS chromatography/Mass spectrometry (GC-MS) , *HYDROFLUORIC acid , *HYDROLYSIS , *ALUMINUM silicates , *POLYSACCHARIDES , *SOIL stabilization , *REUNIONESE - Abstract
Abstract: Organo-mineral complexes play a major role in the stabilisation of organic matter (OM) within soils, but only few data are presently available about the nature of the OM bound to mineral phases. In this study, we aimed at determining the nature of the OM present in various organo-mineral complexes in a tropical soil (Andosol). Organo-mineral complexes were isolated thanks to densimetric separation techniques. The mineral phases of organo-mineral complexes were identified using XRD, and OM was analysed by Py–GC–MS after carbon enrichment obtained through 5% hydrofluoric acid hydrolysis. We thus studied OM bound to poorly crystallised aluminosilicates (PC-AlSi), gibbsite and iron oxides, as well as free-OM (<1.9gcm−3 fraction), which represents OM that is not bound to mineral phases. In the organo-mineral complexes of the studied Andosol, lipids were mainly present with PC-AlSi while polysaccharides and proteins/amino acids were the main organic compounds associated with gibbsite. Lignin compounds were found in high quantities in free-OM but were not found in organo-mineral complexes. Only few organic compounds were bound to iron oxides. Furthermore, proteins/amino acids and lipids were also observed in all organo-mineral complexes, but polysaccharides were not. The present results show that mineral phase type influences not only the proportion but also the nature of the organic compounds present in organo-mineral complexes. This study provides new information about the nature of the OM bound to mineral phases, and will thus contribute to improving models of organo-mineral complexes in order to better understand OM stabilisation in soils. [Copyright &y& Elsevier]
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- 2013
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8. Early degradation of plant alkanes in soils: A litterbag experiment using 13C-labelled leaves
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Nguyen Tu, Thanh Thuy, Egasse, Céline, Zeller, Bernd, Bardoux, Gérard, Biron, Philippe, Ponge, Jean-François, David, Brigitte, and Derenne, Sylvie
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EUROPEAN beech , *SOIL degradation , *ALKANES , *CARBON isotopes , *COMPOSITION of leaves , *HUMUS , *BIODEGRADATION , *MICROSCOPY - Abstract
Abstract: We monitored the carbon isotope composition of bulk leaves and specific long-chain alkanes during a four-year litterbag experiment using 13C-labelled leaves and unlabelled reference leaves of the European beech tree (Fagus sylvatica L.). Whereas the isotope composition of alkanes from 13C-enriched leaves exhibited a marked decrease in 13C-content, the isotope composition of unlabelled reference leaves remained nearly constant. We interpreted this difference as evidence for a microbial contribution to the long-chain alkane pool of the decomposing leaves and related it to the progressive invasion of leaves by soil organisms which was revealed upon microscopic examination. These results suggest that long-chain alkanes may not provide an unaltered record of organic carbon isotope composition in soils and sediments. [Copyright &y& Elsevier]
- Published
- 2011
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9. Occurrence and distribution of non-extractable glycerol dialkyl glycerol tetraethers in temperate and tropical podzol profiles
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Huguet, Arnaud, Fosse, Céline, Metzger, Pierre, Fritsch, Emmanuel, and Derenne, Sylvie
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ETHERS , *SOLVENT extraction , *PODZOL , *MOLECULAR weights , *LIPIDS , *ARTIFICIAL membranes , *ARCHAEBACTERIA , *ORGANIC synthesis - Abstract
Abstract: Glycerol dialkyl glycerol tetraethers (GDGTs) are high molecular weight lipids present in the membranes of archaea and some bacteria. Isoprenoid GDGTs with acyclic or ring containing dibiphytanyl chains are known to be synthesised by archaea. In soil, another type of GDGT, which can be distinguished from tetraethers of archaeal origin by way of the branched nature of the alkyl chain, was discovered recently. Alkyl branched GDGTs were suggested to be produced by anaerobic bacteria and can be used to reconstruct past air temperatures and soil pH. Lipids in soils can take two broad forms: extractable, i.e. recoverable via solvent extraction, and non-extractable, linked to the mineral or organic matrix. The present study aimed at comparing the abundance and distribution of these two pools of GDGTs in two contrasting podzol environments: a temperate podzol 40km north of Paris (France) and a tropical podzol from the Amazon basin (Brazil). Five samples were collected from the whole profile of the temperate podzol. Five additional samples were obtained from three profiles of the tropical soil sequence, which are representative of the transition between a latosol and a well developed podzol. For the first time, we showed that substantial amounts of non-extractable GDGTs can be released after acid hydrolysis of solvent-extracted soils, non-extractable GDGTs representing 25±15% of the total (i.e. extractable+non-extractable) bacterial GDGTs and 29±17% of the total archaeal GDGTs in podzol samples. This implies that extractable GDGTs can be incorporated into the organic and/or mineral matrix of soil. In addition, we observed that extractable and non-extractable GDGTs could present different distribution patterns, notably suggesting that some extractable GDGTs might be preferentially transferred to the non-extractable pool and/or might be preferentially degraded by soil microorganisms. The relative abundances of bacterial and archaeal GDGTs were compared along the temperate soil profile and the tropical soil sequence. The relative amount of bacterial vs. archaeal GDGTs was shown to be much higher in the extractable than in the non-extractable fraction in the surficial horizons of the temperate podzol and in the well-developed part of the tropical podzol, implying that extractable archaeal GDGTs could be preferentially transferred to the non-extractable lipid pool compared to extractable bacterial GDGTs in these horizons. This might be due to the fact that the types of polar head groups associated with bacterial GDGTs differ from, and are more labile than, those associated with archaeal GDGTs. [Copyright &y& Elsevier]
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- 2010
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10. Chemotaxonomical investigations of fossil and extant beeches. II. Leaf lipids of Pliocene Fagus from the Upper Valdarno Basin, central Italy
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Zanetti, Florent, Nguyen Tu, Thanh Thuy, Bertini, Adele, Egasse, Céline, Derenne, Sylvie, and Broutin, Jean
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CHEMOTAXONOMY , *PLANT chemotaxonomy , *FOSSILS , *BEECH , *FOSSIL plants , *MICROALGAE - Abstract
Abstract: The chemical composition of fossil plants can provide useful data for taxonomy and palaeoecological reconstructions. The Upper Valdarno Basin deposit (central Italy) shows a great diversity of well-preserved fossils. The first results of the analysis of Pliocene Fagus leaf lipids are reported here. Series of long chain aliphatic lipids (n-alkanes, n-alcohols, n-aldehydes, n-ketones) dominated the extract. Their distributions differ for the fossil and the extant European beech, suggesting that they may belong to different species. The occurrence of compounds sensitive to degradation such as n-aldehydes and monoglycerids shows the excellent chemical preservation of the fossils. Two long-chain n-alkyl-1,15-diols were identified. They may come from Eustigmatophyceae microalgae, and their occurrence is in agreement with a freshwater deposit ion environment. Various polycyclic terpenoids were detected (e.g., native plant sterols, triterpenoids of the oleanane type). The occurrence of compounds that do not correspond to Fagus lipids is discussed. [Copyright &y& Elsevier]
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- 2007
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11. Chemotaxonomical investigations of fossil and extant beeches. I. Leaf lipids from the extant Fagus sylvatica L.
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Nguyen-Tu, Thanh Thuy, Egasse, Céline, Zeller, Bernd, and Derenne, Sylvie
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FOSSIL plants , *PLANT classification , *TAPHONOMY , *EUROPEAN beech , *CHROMATOGRAPHIC analysis , *GAS chromatography - Abstract
Abstract: The chemistry of fossil plants can help in precising their taxonomic affinities as well as their taphonomic history. The lipids from mature leaves of Fagus sylvatica L. were thus characterised to identify the components potentially informative that might be preserved in fossil beeches. Gas chromatography–mass spectrometry analyses of the lipids revealed a complex mixture comprising more than 60 identified constituents, belonging to diverse chemical families (e.g., sterols, fatty lipids, acyclic isoprenoids, triterpenes, glycerols, esters). Although most of the identified components are reported here for the first time in the European beech, they predominantly correspond to rather common compounds in Angiosperms. Nevertheless, their co-occurrence may constitute a useful fingerprint in further chemotaxonomic investigations of beeches. The newly reported compounds also include degradation products of plant lipids and fungal markers, showing that these degradation markers are to be considered as molecules related to the leaves in further taphonomic studies. [Copyright &y& Elsevier]
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- 2007
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12. Lipids and their modes of occurrence in two surface sediments from the Danube delta and northwestern Black Sea: implications for sources and early diagenetic alteration: I. Carboxylic acids
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Garcette-Lepecq, Anouk, Largeau, Claude, Bouloubassi, Ioanna, Derenne, Sylvie, Saliot, Alain, Lorre, Anne, and Point, Vanessa
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LIPIDS , *CARBOXYLIC acids , *BIOMOLECULES , *ORGANIC acids - Abstract
Two surface sediments from the Danube delta and an adjacent area of the northwestern Black Sea were subjected to sequential treatment in order to obtain comprehensive qualitative and quantitative information on carboxylic acid moieties. Four acid fractions, corresponding to distinct pools, were thus obtained from each sample: (1) an organic solvent-extractable fraction corresponding to the “unbound” acids, (2) an “OH--labile” fraction (released by classical alkaline hydrolysis of the solvent-extracted material) corresponding to the ester-bound acids, (3) a “H+-labile” fraction (obtained via subsequent acid hydrolysis of extracted and base-hydrolysed material) corresponding to amide- and/or ether-bound acids, (4) the “tightly-bound” acids released by TMAH thermochemolysis of the insoluble, non-hydrolysable and HF/HCl-resistant material. The existence of these four pools of acids reflects differences in the mode of linkage of the acid moieties and/or in the protection provided by the (macro)molecular structures into which they are incorporated.Considerable qualitative and quantitative differences were observed, for a given sample, depending on the particular pool, and large differences were also noted, for a given pool, between the two samples.The biogeochemical investigation of the carboxylic acids according to their modes of occurrence in these two surface sediments with contrasting locations provides information on (i) the relative importance of microalgal, bacterial and terrestrial contributions in surface sediments, as well as the types of species implicated and (ii) the extent of early diagenetic alteration. [Copyright &y& Elsevier]
- Published
- 2004
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