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Author Cottet, K.; Fromentin, Y.; Kritsanida, M.; Grougnet, R.; Odonne, G.; Duplais, C.; Michel, S.; Lallemand, M.-C.
Title Isolation of Guttiferones from Renewable Parts of Symphonia globulifera by Centrifugal Partition Chromatography Type Journal Article
Year 2015 Publication Planta Medica Abbreviated Journal Planta Medica
Volume 81 Issue 17 Pages 1604-1608
Keywords centrifugal partition chromatography; Clusiaceae; countercurrent chromatography guttiferones; PPAPs; Symphonia globulifera
Abstract The aim of this study was to investigate the species Symphonia globulifera, a source of polycyclic polyprenylated acyl phloroglucinols such as guttiferone A, which is known to exhibit a variety of biological activities including noticeable antileishmanial properties. Our goal was the identification and the quantification of guttiferone A in different renewable parts of S. globulifera and its preparative isolation. To the best of our knowledge, there is no data concerning its mechanism of action. Consequently, it is particularly interesting to isolate it in gram quantities in order to establish structure activity relationship studies. After performing high-performance liquid chromatography profiles detecting the presence of guttiferone A and proceeding to its quantification, a centrifugal partition chromatography methodology using a two-phase solvent system of cyclohexane/ethyl acetate/methanol/water (20 : 1 : 20 : 1, v/v/v/v) was applied to each extract. In conclusion, a centrifugal partition chromatography system has been developed to ensure a fast, reliable, and scalable way to isolate, with a high level of purity, guttiferone A from five renewable parts of S. globulifera. Moreover, this methodology can be extended to the isolation of other polycyclic polyprenylated acyl phloroglucinols such as guttiferones B, C, and D. © Georg Thieme Verlag KG Stuttgart.
Address (down) Laboratoire des Substances Naturelles Amazoniennes, Institut Pasteur de la Guyane, UMR EcoFoG (Ecologie des forêts de Guyane), Cayenne, France
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Notes Export Date: 7 January 2016 Approved no
Call Number EcoFoG @ webmaster @ Serial 646
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Author Barraza, F.; Schreck, E.; Lévêque, T.; Uzu, G.; Lopez, F.; Ruales, J.; Prunier, J.; Marquet, A.; Maurice, L.
Title Cadmium bioaccumulation and gastric bioaccessibility in cacao: A field study in areas impacted by oil activities in Ecuador Type Journal Article
Year 2017 Publication Environmental Pollution Abbreviated Journal
Volume 229 Issue Pages 950-963
Keywords Cacao; Cadmium; Ecuador; Health risk assessment; Uptake and bioaccumulation
Abstract Cacao from South America is especially used to produce premium quality chocolate. Although the European Food Safety Authority has not established a limit for cadmium (Cd) in chocolate raw material, recent studies demonstrate that Cd concentrations in cacao beans can reach levels higher than the legal limits for dark chocolate (0.8 mg kg−1, effective January 1st, 2019). Despite the fact that the presence of Cd in agricultural soils is related to contamination by fertilizers, other potential sources must be considered in Ecuador. This field study was conducted to investigate Cd content in soils and cacao cultivated on Ecuadorian farms in areas impacted by oil activities. Soils, cacao leaves, and pod husks were collected from 31 farms in the northern Amazon and Pacific coastal regions exposed to oil production and refining and compared to two control areas. Human gastric bioaccessibility was determined in raw cacao beans and cacao liquor samples in order to assess potential health risks involved. Our results show that topsoils (0–20 cm) have higher Cd concentrations than deeper layers, exceeding the Ecuadorian legislation limit in 39% of the sampling sites. Cacao leaves accumulate more Cd than pod husks or beans but, nevertheless, 50% of the sampled beans have Cd contents above 0.8 mg kg−1. Root-to-cacao transfer seems to be the main pathway of Cd uptake, which is not only regulated by physico-chemical soil properties but also agricultural practices. Additionally, natural Cd enrichment by volcanic inputs must not be neglected. Finally, Cd in cacao trees cannot be considered as a tracer of oil activities. Assuming that total Cd content and its bioaccessible fraction (up to 90%) in cacao beans and liquor is directly linked to those in chocolate, the health risk associated with Cd exposure varies from low to moderate.
Address (down) Laboratoire des Sciences du Bois, UMR EcoFoG, ZI Pariacabo, Kourou, French Guiana
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Notes Cited By :1; Export Date: 4 June 2018 Approved no
Call Number EcoFoG @ webmaster @ Serial 806
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Author Rivalland, C.; Madhkour, S.; Salvin, P.; Robert, F.
Title Electrochemical and microbial monitoring of multi-generational electroactive biofilms formed from mangrove sediment Type Journal Article
Year 2015 Publication Bioelectrochemistry Abbreviated Journal Bioelectrochemistry
Volume 106 Issue Pages 125-132
Keywords Dissimilarity; High-throughput sequencing; Mes; Microbial diversity; Syntrophism
Abstract Electroactive biofilms were formed from French Guiana mangrove sediments for the analysis of bacterial communities' composition. The electrochemical monitoring of three biofilm generations revealed that the bacterial selection occurring at the anode, supposedly leading microbial electrochemical systems (MESs) to be more efficient, was not the only parameter to be taken into account so as to get the best electrical performance (maximum current density). Indeed, first biofilm generations produced a stable current density reaching about 18A/m2 while second and third generations produced current densities of about 10A/m2. MES bacterial consortia were characterized thanks to molecular biology techniques: DGGE and MiSeq® sequencing (Illumina®). High-throughput sequencing data statistical analysis confirmed preliminary DGGE data analysis, showing strong similarities between electroactive biofilms of second and third generations, but also revealing both selection and stabilization of the biofilms. © 2015 Elsevier B.V.
Address (down) Laboratoire des Matériaux et Molécules en Milieu Amazonien, UAG-UMR EcoFoG, 2091 route de Baduel, Campus TrouBiran, Cayenne, Guyane Française, France
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Notes Export Date: 11 September 2015 Approved no
Call Number EcoFoG @ webmaster @ Serial 622
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Author Salhi, L.; Nait-Rabah, O.; Deyrat, C.; Roos, C.
Title Numerical Modeling of Single Helical Pile Behavior under Compressive Loading in Sand Type Journal Article
Year 2013 Publication Electronic Journal of Geotechnical Engineering Abbreviated Journal Electron. J. Geotech. Eng.
Volume 18 Issue Bundle T Pages 4119-4338
Keywords helical pile; finite element method; failure mechanisms; sand
Abstract The present research deals with helical piles behavior in cohesionless soil through finite element modeling. An approach of modeling of the screw-pile geometry has been proposed through the Finite Element Analysis (FEA) computer program Plaxis. The numerical results are compared with measurements from large scale test and the bearing capacity has been estimated using both cylindrical and individual bearing model. Moreover, different failure criterions have been applied to estimate the ultimate capacity. The effect of spacing ratio (S/Dh) on the screw-pile behavior has been further studied. It has found that results from the model fit the field results. Through the study of the load transfer mechanism, the transition from cylindrical shear to individual plate behavior occurs at a value of spacing ratio (1.5 to 2).
Address (down) Laboratoire des matériaux et molécules en milieu amazonien, EcoFoG-Université des Antilles-Guyane, 97351 Cayenne, French Guiana
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Call Number EcoFoG @ webmaster @ Serial 525
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Author Vastra, M.; Salvin, P.; Roos, C.
Title MIC of carbon steel in Amazonian environment: Electrochemical, biological and surface analyses Type Journal Article
Year 2016 Publication International Biodeterioration and Biodegradation Abbreviated Journal International Biodeterioration and Biodegradation
Volume 112 Issue Pages 98-107
Keywords Biology; Electrochemistry; Mic; Short term; Surface analyses
Abstract In this study, the corrosion of S355 carbon steel was monitored for 50 days in equatorial environment. The experiments were conducted under three complementary approaches in a natural environment: (i) bacterial diversity was assessed with Miseq sequencing, (ii) observations of the surface and identifications of deposit compounds were realised with scanning electron microscopy (SEM), Raman spectrometry and EDX analyses, (iii) electrochemical measurements were used to calculate corrosion rate and to identify the phenomena which control corrosion. The results showed that the bacterial population had changed over immersion time from a dominance of β-proteobacteria to α-proteobacteria. This evolution decreased charge transfer resistance at the metal/deposit from 41.6 to 20.8 Ω/cm2 in 50 days, caused an increase in the corrosion rate by a factor of 2, from 0.13 to 0.27 mm/year. Surface analyses showed a progressive appearance of MIC markers in the deposit such as iron sulphide and manganese oxides that were detected after 30 days of immersion in the natural environment. In conclusion, this study describes in detail, the first stage of MIC activity on carbon steel surface in an equatorial brackish water, under aerobic conditions. © 2016 Elsevier Ltd.
Address (down) Laboratoire des Matériaux et Molécules en Milieu Agressif, Université des Antilles, UMR ECOFOG, Campus Universitaire, Schœlcher, Martinique
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Notes Export Date: 1 June 2016 Approved no
Call Number EcoFoG @ webmaster @ Serial 681
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Author Salvin, P.; Roos, C.; Robert, F.
Title Tropical mangrove sediments as a natural inoculum for efficient electroactive biofilms Type Journal Article
Year 2012 Publication Bioresource Technology Abbreviated Journal Bioresour. Technol.
Volume 120 Issue Pages 45-51
Keywords Chronoamperometry; Cyclic voltammetry; Electroactive biofilms; Microbial fuel cells; Three-electrode systems
Abstract Chronoamperometry is known to be an efficient way to form electroactive biofilms (EAB) on conductive electrodes. For the first time, tropical mangrove sediments are analyzed as a potential inoculum to form MFC anodes with the use of acetate as substrate. The performance of the EAB-coated carbon cloth electrodes are evaluated according to the maximal current density, the coulombic efficiency and the cyclic voltammogramms. Working electrodes (WE) polarized at -0.2V/SCE gave better results compared to -0.4V/SCE and 0.0V/SCE. The maximal current density attained was 12A/m 2 with a CE of 24%. Contributions of the EAB in the generation of current were discussed and mechanisms of electronic transfer by the bacteria were discussed. Epifluorescence and SEM images showed the evolution of the biofilms on the electrode surface and the heterogeneity of the structure. © 2012 Elsevier Ltd.
Address (down) Laboratoire des Matériaux et des Molécules en Milieu Amazonien, Université des Antilles et de la Guyane, UAG-UMR ECOFOG, F-97337 Cayenne, French Guiana
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Notes Export Date: 16 August 2012; Source: Scopus; Coden: Birte; doi: 10.1016/j.biortech.2012.05.131; Language of Original Document: English; Correspondence Address: Robert, F.; Laboratoire des Matériaux et des Molécules en Milieu Amazonien, Université des Antilles et de la Guyane, UAG-UMR ECOFOG, F-97337 Cayenne, French Guiana; email: florent.robert@guyane.univ-ag.fr Approved no
Call Number EcoFoG @ webmaster @ Serial 421
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Author Leroy, C.; Jauneau, A.; Martinez, Y.; Cabin-Flaman, A.; Gibouin, D.; Orivel, J.; Séjalon-Delmas, N.
Title Exploring fungus-plant N transfer in a tripartite ant-plant-fungus mutualism Type Journal Article
Year 2017 Publication Annals of Botany Abbreviated Journal Annals of Botany
Volume 120 Issue 3 Pages 417-426
Keywords Ascomycetes; endophytic fungi; Hirtella physophora; microscopy; mutualism; myrmecophyte; NanoSIMS; stable isotope
Abstract Background and Aims The plant Hirtella physophora, the ant Allomerus decemarticulatus and a fungus, Trimmatostroma sp., form a tripartite association. The ants manipulate both the plant trichomes and the fungus to build galleries under the stems of their host plant used to capture prey. In addition to its structural role, the fungus also improves nutrient uptake by the host plant. But it still remains unclear whether the fungus plays an indirect or a direct role in transferring nutrients to the plant. This study aimed to trace the transfer of N from the fungus to the plant's stem tissue. • Methods Optical microscopy and transmission electron microscopy (TEM) were used to investigate the presence of fungal hyphae in the stem tissues. Then, a 15N-labelling experiment was combined with a nanoscale secondary-ion mass spectrometry (NanoSIMS 50) isotopic imaging approach to trace the movement of added 15N from the fungus to plant tissues. • Key Results The TEM images clearly showed hyphae inside the stem tissue in the cellular compartment. Also, fungal hyphae were seen perforating the wall of the parenchyma cell. The 15N provisioning of the fungus in the galleries resulted in significant enrichment of the 15N signature of the plant's leaves 1 d after the 15N-labelling solution was deposited on the fungus-bearing trap. Finally, NanoSIMS imaging proved that nitrogen was transferred biotrophically from the fungus to the stem tissue. • Conclusions This study provides evidence that the fungi are connected endophytically to an ant-plant system and actively transfer nitrogen from 15N-labelling solution to the plant's stem tissues. Overall, this study underlines how complex the trophic structure of ant-plant interactions is due to the presence of the fungus and provides insight into the possibly important nutritional aspects and tradeoffs involved in myrmecophyte-ant mutualisms. © The Author 2017.
Address (down) Laboratoire de Recherches en Sciences Végétales, Université de Toulouse, CNRS, UPS, France
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Notes Export Date: 2 October 2017 Approved no
Call Number EcoFoG @ webmaster @ Serial 767
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Author Dejean, A.; Delabie, J.H.C.; Cerdan, P.; Gibernau, M.; Corbara, B.
Title Are myrmecophytes always better protected against herbivores than other plants? Type Journal Article
Year 2006 Publication Biological Journal of the Linnean Society Abbreviated Journal Biol. J. Linn. Soc.
Volume 89 Issue 1 Pages 91-98
Keywords Ant-plant mutualism; Azteca; Maieta; Myrmecophytes; Plant protection; Tococa; ant; defoliation; field method; mutualism; myrmecophyte; plant-herbivore interaction; Azteca; Azteca bequaerti; Clidemia; Crematogaster laevis; Formicidae; Maieta; Maieta guianensis; Pheidole minutula; Tococa; Tococa guianensis
Abstract The present field study compared the degree of defoliation of three Guianian melastome, two myrmecophytes (i.e. plants sheltering ants in hollow structures) and Clidemia sp., a nonmyrmecophytic plant serving as a control. Maieta guianensis Aubl. hosted mostly Pheidole minutula Mayr whatever the area, whereas Tococa guianensis Aubl. hosted mostly Azteca bequaerti Wheeler along streams and Crematogaster laevis Mayr or Azteca sp. 1 in the understory where it never blossomed. Only Tococa, when sheltering A. bequaerti in what can be considered as a truly mutualistic relationship, showed significantly less defoliation than control plants. In the other associations, the difference was not significant, but P. minutula is mutualistic with Maieta because it furnishes some protection (exclusion experiments) plus nutrients (previous studies). When devoid of ants, Tococa showed significantly greater defoliation than control plants; therefore, it was deduced that Tococa probably lacks certain antidefoliator metabolites that control plants possess (both Tococa and control plants are protected by ground-nesting, plant-foraging ants, which is termed 'general myrmecological protection'). Consequently, plant-ants other than A. bequaerti probably also protect Tococa slightly, thus compensating for this deficiency and permitting it to live in the understory until treefall gaps provide the conditions necessary for seed production. © 2006 The Linnean Society of London.
Address (down) Laboratoire de Psychologie Sociale de la Cognition (UMR CNRS 6024), Université Blaise Pascal, 34 avenue Carnot, 63037 Clermont-Ferrand Cedex, France
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Notes Cited By (since 1996): 9; Export Date: 22 October 2011; Source: Scopus; Coden: Bjlsb; doi: 10.1111/j.1095-8312.2006.00660.x; Language of Original Document: English; Correspondence Address: Dejean, A.; Laboratoire d'Evolution et Diversité Biologique (UMR CNRS 5174), Université Toulouse III, Bâtiment 4R3, 118 route de Narbonne, 31062 Toulouse Cedex, France; email: dejean@cict.fr Approved no
Call Number EcoFoG @ webmaster @ Serial 355
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Author Rodrigues, A.M.S.; Stien, D.; Eparvier, V.; Espindola, L.S.; Beauchene, J.; Amusant, N.; Lemenager, N.; Baudasse, C.; Raguin, L.
Title The wood preservative potential of long-lasting Amazonian wood extracts Type Journal Article
Year 2012 Publication International Biodeterioration and Biodegradation Abbreviated Journal
Volume 75 Issue Pages 146-149
Keywords Durable wood extracts; Handroanthus serratifolius; Rotting fungi; Wood preservation
Abstract Investigations were carried out on the efficacy of extracts from seven Amazonian woods (Bagassa guianensis, Manilkara huberi, Sextonia rubra, Vouacapoua americana, Andira surinamensis, Handroanthus serratifolius, and Qualea rosea) with varying natural durability to reduce soft-rot degradation in a 6-wk soil-bed test. Six of the wood extracts had shown efficacy against soft-rot fungi. In particular, the preservation efficacies of B. guianensis, H. serratifolius, and S. rubra extracts were highly significant up to retention levels of 23, 25, and 12 kg m-3, respectively. Three extracts (A. surinamensis, H. serratifolius, and Q. rosea) were then tested against Gloeophyllum trabeum (brown rot) and Trametes versicolor (white rot), in an agar-block test. H. serratifolius wood extract was very efficient at protecting P. sylvestris samples at 5.1 kg m-3 against the brown rot. This extract could be used as a basis for new wood protectant formulations. © 2012 Elsevier Ltd.
Address (down) Laboratoire de Préservation, CIRAD, 73 rue JF Breton, Montpellier 34398, TA B 40-16, cedex 5, France
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Notes Export Date: 15 January 2013; Source: Scopus Approved no
Call Number EcoFoG @ webmaster @ Serial 457
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Author Lebrini, M.; Mbomekallé, I.M.; Dolbecq, A.; Marrot, J.; Berthet, P.; Ntienoue, J.; Sécheresse, F.; Vigneron, J.; Etcheberry, A.
Title Manganese(III)-containing wells-dawson sandwich-type polyoxometalates: Comparison with their manganese(II) counterparts Type Journal Article
Year 2011 Publication Inorganic Chemistry Abbreviated Journal Inorg. Chem.
Volume 50 Issue 14 Pages 6437-6448
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Abstract We present the synthesis and structural characterization, assessed by various techniques (FTIR, TGA, UV-vis, elemental analysis, single-crystal X-ray diffraction for three compounds, magnetic susceptibility, and electrochemistry) of five manganese-containing Wells-Dawson sandwich-type (WDST) complexes. The dimanganese(II)-containing complex, [Na2(H2O) 2MnII2(As2W15O 56)2]18- (1), was obtained by reaction of MnCl2 with 1 equiv of [As2W15O 56]12- in acetate medium (pH 4.7). Oxidation of 1 by Na2S2O8 in aqueous solution led to the dimanganese(III) complex [Na2(H2O)2Mn III2(As2W15O56) 2]16- (2), while its trimanganese(II) homologue, [Na(H2O)2MnII(H2O)Mn II2(As2W15O56) 2]17- (3), was obtained by addition of ca. 1 equiv of MnCl2 to a solution of 1 in 1 M NaCl. The trimanganese(III) and tetramanganese(III) counterparts, [MnIII(H2O)Mn III2(As2W15O56) 2]15- (4) and [MnIII2(H 2O)2MnIII2(As2W 15O56)2]12- (6), are, respectively, obtained by oxidation of aqueous solutions of 3 and [MnII2(H2O)2MnII2(As 2W15O56)2]16- (5) by Na2S2O8. Single-crystal X-ray analyses were carried out on 2, 3, and 4. BVS calculations and XPS confirmed that the oxidation state of Mn centers is +II for complexes 1, 3, and 5 and +III for 2, 4, and 6. A complete comparative electrochemical study was carried out on the six compounds cited above, and it was possible to observe the distinct redox steps MnIV/III and MnIII/II. Magnetization measurements, as a function of temperature, confirm the presence of antiferromagnetic interactions between the Mn ions in these compounds in all cases with the exception of compound 2. © 2011 American Chemical Society.
Address (down) Laboratoire de Physico-Chimie de L'Etat Solide, ICMMO, Université Paris-Sud, Bâtiment 410, 91405 Orsay Cedex, France
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Notes Export Date: 21 October 2011; Source: Scopus; Coden: Inoca; doi: 10.1021/ic102237x; Language of Original Document: English; Correspondence Address: Mbomekallé, I.M.; Institut Lavoisier de Versailles, UMR 8180, CNRS Université de Versailles Saint-Quentin, 45 Avenue des Etats-Unis, 78035 Versailles Cedex, France; email: israel.mbomekalle@chimie.uvsq.fr Approved no
Call Number EcoFoG @ webmaster @ Serial 346
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