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Author Nirma, C.; Eparvier, V.; Stien, D.
Title Antifungal agents from Pseudallescheria boydii SNB-CN73 isolated from a nasutitermes sp. termite Type Journal Article
Year 2013 Publication Journal of Natural Products Abbreviated Journal J. Nat. Prod.
Volume (up) 76 Issue 5 Pages 988-991
Keywords
Abstract Defense mutualisms between social insects and microorganisms have been described in the literature. The present article describes the discovery of a Pseudallescheria boydii strain isolated from Nasutitermes sp. The microbial symbiont produces two antifungal metabolites: tyroscherin and N-methyltyroscherin, a compound not previously described in the literature. Methylation of tyroscherin has confirmed the structure of N-methyltyroscherin. Both compounds are effective antifungal agents with favorable selectivity indices for Candida albicans and Trichophyton rubrum. © 2013 The American Chemical Society and American Society of Pharmacognosy.
Address UMR Ecofog, Institut Pasteur de la Guyane, Université des Antilles et de la Guyane, 23 Avenue Pasteur, 97306 Cayenne, France
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ISSN 01633864 (Issn) ISBN Medium
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Notes Export Date: 6 June 2013; Source: Scopus; Coden: Jnprd; :doi 10.1021/np4001703; Language of Original Document: English; Correspondence Address: Eparvier, V.; CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 1 Avenue de la Terrasse, 91198 Gif-sur-Yvette, France; email: veronique.eparvier@icsn.cnrs-gif.fr Approved no
Call Number EcoFoG @ webmaster @ Serial 491
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Author Ghislain, B.; Alméras, T.; Prunier, J.; Clair, B.
Title Contributions of bark and tension wood and role of the G-layer lignification in the gravitropic movements of 21 tropical tree species Type Journal Article
Year 2019 Publication Annals of Forest Science Abbreviated Journal Ann. Forest Sci.
Volume (up) 76 Issue 4 Pages 107
Keywords Bark; Biomechanics; G-layer; Lignification; Tension wood; Tropical rainforest; Magnoliophyta
Abstract Key message: Gravitropic movements in angiosperm woody stems are achieved through the action of bark and/or wood motor, depending on the bark and wood fibre anatomy (with trellis structure or not; with G-layers or not). Bark motor is as efficient as wood motor to recover from tilting in young trees of 21 tropical species. Context: Angiosperm trees produce tension wood to control their orientation through changes in stem curvature. Tension wood is classified into 3 anatomical groups: with unlignified G-layer, with lignified G-layer and without G-layer. Aims: This study aimed at assessing whether this anatomical diversity reflects a diversity in efficiency of gravitropic movement. Methods: The study was conducted on tropical seedling from the three anatomical groups. Seedlings were staked and grown tilted. At the end of the experiment, changes in curvature when releasing the stem from the stake and when removing bark were measured. Three parameters were computed to compare the global efficiency of gravitropism (stem gravitropic efficiency) and the specific efficiency of motor mechanism based on wood (maturation strain of tension wood) and bark (standardized debarking curvature). Results: The maturation strain of tension wood was similar between species with unlignified and lignified G-layer. Species without G-layer exhibited low maturation strain and large debarking curvature, showing they rely on bark for gravitropism. Bark and wood achieved similar motor efficiency. Conclusion: Lignin does not affect the generation of tensile stress in the G-layer. Bark can be as efficient as wood as a motor of gravitropic movements. © 2019, The Author(s).
Address Laboratoire de Mécanique et Génie Civil (LMGC), Université de Montpellier, CNRS, Montpellier, 34095, France
Corporate Author Thesis
Publisher Springer Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 12864560 (Issn) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 900
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Author Ziegler, C.; Coste, S.; Stahl, C.; Delzon, S.; Levionnois, S.; Cazal, J.; Cochard, H.; Esquivel-Muelbert, A.; Goret, J.-Y.; Heuret, P.; Jaouen, G.; Santiago, L.S.; Bonal, D.
Title Large hydraulic safety margins protect Neotropical canopy rainforest tree species against hydraulic failure during drought Type Journal Article
Year 2019 Publication Annals of Forest Science Abbreviated Journal Ann. Forest Sci.
Volume (up) 76 Issue 4 Pages 115
Keywords Amazon rainforest; Embolism resistance; Hydraulic safety margins; Turgor loss point; Water potential
Abstract Key message: Abundant Neotropical canopy-tree species are more resistant to drought-induced branch embolism than what is currently admitted. Large hydraulic safety margins protect them from hydraulic failure under actual drought conditions. Context: Xylem vulnerability to embolism, which is associated to survival under extreme drought conditions, is being increasingly studied in the tropics, but data on the risk of hydraulic failure for lowland Neotropical rainforest canopy-tree species, thought to be highly vulnerable, are lacking. Aims: The purpose of this study was to gain more knowledge on species drought-resistance characteristics in branches and leaves and the risk of hydraulic failure of abundant rainforest canopy-tree species during the dry season. Methods: We first assessed the range of branch xylem vulnerability to embolism using the flow-centrifuge technique on 1-m-long sun-exposed branches and evaluated hydraulic safety margins with leaf turgor loss point and midday water potential during normal- and severe-intensity dry seasons for a large set of Amazonian rainforest canopy-tree species. Results: Tree species exhibited a broad range of embolism resistance, with the pressure threshold inducing 50% loss of branch hydraulic conductivity varying from − 1.86 to − 7.63 MPa. Conversely, we found low variability in leaf turgor loss point and dry season midday leaf water potential, and mostly large, positive hydraulic safety margins. Conclusions: Rainforest canopy-tree species growing under elevated mean annual precipitation can have high resistance to embolism and are more resistant than what was previously thought. Thanks to early leaf turgor loss and high embolism resistance, most species have a low risk of hydraulic failure and are well able to withstand normal and even severe dry seasons. © 2019, The Author(s).
Address Smithsonian Tropical Research Institute, Balboa, Ancon, Panama
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Publisher Springer Place of Publication Editor
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ISSN 12864560 (Issn) ISBN Medium
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Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 901
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Author Leroy, C.; Sabatier, S.; Wahyuni, N.S.; Barczi, J.F.; Dauzat, J.; Laurans, M.; Auclair, D.
Title Virtual trees and light capture: a method for optimizing agroforestry stand design Type Journal Article
Year 2009 Publication Agroforestry Systems Abbreviated Journal Agrofor. Syst.
Volume (up) 77 Issue 1 Pages 37-47
Keywords Acacia mangium; Tectona grandis; Agroforestry; Light interception; Plant architecture; Simulation; 3D virtual plant
Abstract In agroforestry systems, the distribution of light transmitted under tree canopies can be a limiting factor for the development of intercrops. The light available for intercrops depends on the quantity of light intercepted by tree canopies and, consequently, on the architecture of the tree species present. The influence of tree architecture on light transmission was analysed using dynamic 3D architectural models. The architectural analysis of Acacia mangium and Tectona grandis was performed in Indonesian agroforestry systems with trees aged from 1 to 3 years. 3D virtual trees were then generated with the AmapSim simulation software and 3D virtual experiments in which tree age, planting density, planting pattern and pruning intensity varied were reconstructed in order to simulate light available for the crop. Canopy closure of trees was more rapid in A. mangium than in T. grandis agroforestry systems; after 3 years the quantity of light available for A. mangium intercrops was three times lower than under T. grandis. Simulations with A. mangium showed that practices such as pruning and widening tree spacing enable to increase the total transmitted light within the stand. On T. grandis, modification of the tree row azimuth resulted in changes in the spatial and seasonal distribution of light available for the intercrops. These results are discussed in terms of agroforestry system management.
Address [Sabatier, Sylvie; Barczi, Jean-Francois; Dauzat, Jean; Laurans, Marilyne] CIRAD, UMR AMAP Botan & Bioinformat Architecture Plantes, F-34398 Montpellier 5, France, Email: sylvie-annabel.sabatier@cirad.fr
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Publisher SPRINGER Place of Publication Editor
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ISSN 0167-4366 ISBN Medium
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Notes ISI:000268865600004 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 199
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Author Salas-Lopez, A.
Title Predicting resource use in ant species and entire communities by studying their morphological traits: Influence of habitat and subfamily Type Journal Article
Year 2017 Publication Ecological Indicators Abbreviated Journal Ecol. Indic.
Volume (up) 78 Issue Pages 183-191
Keywords Biodiversity-ecosystem functioning relationships; Ecosystem process; Food niche; Formicidae; Habitat filtering; Indicator; Land-use; Morphological traits; Taxonomic conservatism; Biodiversity; Ecology; Indicators (instruments); Land use; Natural resources management; Ecosystem functioning; Ecosystem process; Formicidae; Morphological traits; Taxonomic conservatism; Ecosystems; Formicidae
Abstract I investigated whether the morphological traits of Neotropical ants can be used to infer food resource use by individual species and by entire communities, and whether these relationships are related to habitat type and/or by morphological differences between ant subfamilies. I attracted ants using food baits that represented different ecological processes (e.g. predation, granivory, detritivory, nectarivory) in five habitat types along a land-use gradient (from forests to gardens). I assessed ant activity at the baits and characterized 64 species from six subfamilies according to their food use and community-level resource exploitation intensity in the different habitats. Next, I performed a Mantel test to reveal the relationships between 13 morphological measures and resource use at the species level. I then used ant clades (i.e. subfamily) and habitat to rank the ants along three axes of variation in relation to their morphology and food resource use. Finally, I tested whether associations existed between the community-level exploitation intensity for such resources and the distribution of morphological trait values using the “4th-corner” analysis. Morphological traits were closely linked to the species’ ability to exploit different resources. These relationships were affected by subfamily and, to a lesser extent, by habitat type. The characterization of trait sets for entire communities was not useful, however, in predicting the intensity of the exploitation of different types of resources in varying environmental conditions. I conclude that morphological traits are accurate predictors of the ecology of species, but they should be used with caution when trying to understand community-level patterns. © 2017 Elsevier Ltd
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Notes Export Date: 8 April 2017 Approved no
Call Number EcoFoG @ webmaster @ Serial 747
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Author Levionnois, Sébastien ; Ziegler, Camille ; Heuret, Patrick ; Jansen, Steven ; Stahl, Clément ; Calvet, Emma ; Goret, Jean-Yves ; Bonal, Damien ; Coste, Sabrina
Title Is vulnerability segmentation at the leaf‑stem transition a drought resistance mechanism? A theoretical test with a trait‑based model for Neotropical canopy tree species Type Journal Article
Year 2021 Publication Annals of Forest Science Abbreviated Journal
Volume (up) 78 Issue 4 Pages 78-87
Keywords Neotropics, bark, canopy, capacitance, drought, drought tolerance, embolism, leaves, models, transpiration, trees, tropical rain forests, xylem
Abstract Leaf-stem vulnerability segmentation predicts lower xylem embolism resistance in leaves than stem. However, although it has been intensively investigated these past decades, the extent to which vulnerability segmentation promotes drought resistance is not well understood. Based on a trait-based model, this study theoretically supports that vulnerability segmentation enhances shoot desiccation time across 18 Neotropical tree species. CONTEXT: Leaf-stem vulnerability segmentation predicts lower xylem embolism resistance in leaves than stems thereby preserving expensive organs such as branches or the trunk. Although vulnerability segmentation has been intensively investigated these past decades to test its consistency across species, the extent to which vulnerability segmentation promotes drought resistance is not well understood. AIMS: We investigated the theoretical impact of the degree of vulnerability segmentation on shoot desiccation time estimated with a simple trait-based model. METHODS: We combined data from 18 tropical rainforest canopy tree species on embolism resistance of stem xylem (flow-centrifugation technique) and leaves (optical visualisation method). Measured water loss under minimum leaf and bark conductance, leaf and stem capacitance, and leaf-to-bark area ratio allowed us to calculate a theoretical shoot desiccation time (tcᵣᵢₜ). RESULTS: Large degrees of vulnerability segmentation strongly enhanced the theoretical shoot desiccation time, suggesting vulnerability segmentation to be an efficient drought resistance mechanism for half of the studied species. The difference between leaf and bark area, rather than the minimum leaf and bark conductance, determined the drastic reduction of total transpiration by segmentation during severe drought. CONCLUSION: Our study strongly suggests that vulnerability segmentation is an important drought resistance mechanism that should be better taken into account when investigating plant drought resistance and modelling vegetation. We discuss future directions for improving model assumptions with empirical measures, such as changes in total shoot transpiration after leaf xylem embolism.
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Call Number EcoFoG @ webmaster @ Serial 1034
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Author Campillo, F.; Rakotozafy, R.; Rossi, V.
Title Parallel and interacting Markov chain Monte Carlo algorithm Type Journal Article
Year 2009 Publication Mathematics and Computers in Simulation Abbreviated Journal Math. Comput. Simul.
Volume (up) 79 Issue 12 Pages 3424-3433
Keywords Markov chain Monte Carlo method; Interacting chains; Hidden Markov model
Abstract In many situations it is important to be able to propose N independent realizations of a given distribution law. We propose a strategy for making N parallel Monte Carlo Markov chains (MCMC) interact in order to get an approximation of an independent N-sample of a given target law. In this method each individual chain proposes candidates for all other chains. We prove that the set of interacting chains is itself a MCMC method for the product of N target measures. Compared to independent parallel chains this method is more time consuming. but we show through examples that it possesses many advantages. This approach is applied to a biomass evolution model. (C) 2009 IMACS. Published by Elsevier B.V. All rights reserved.
Address [Rossi, Vivien] CIRAD, Res Unit, Montpellier, France, Email: Fabien.Campillo@inria.fr
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Publisher ELSEVIER SCIENCE BV Place of Publication Editor
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ISSN 0378-4754 ISBN Medium
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Notes ISI:000269289100006 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 197
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Author Touré, S.; Nirma, C.; Falkowski, M.; Dusfour, I.; Boulogne, I.; Jahn-Oyac, A.; Coke, M.; Azam, D.; Girod, R.; Moriou, C.; Odonne, G.; Stien, D.; Houel, E.; Eparvier, V.
Title Aedes aegypti Larvicidal Sesquiterpene Alkaloids from Maytenus oblongata Type Journal Article
Year 2017 Publication Journal of Natural Products Abbreviated Journal Journal of Natural Products
Volume (up) 80 Issue 2 Pages 384-390
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Abstract Four new sesquiterpene alkaloids (1-4) with a β-dihydroagrofuran skeleton and a new triterpenoid (5) were isolated from an ethyl acetate extract of Maytenus oblongata stems. Their structures were elucidated using 1D and 2D NMR spectroscopy as well as MS and ECD experiments. The M. oblongata stem EtOAc extract and the pure compounds isolated were tested for larvicidal activity against Aedes aegypti under laboratory conditions, and compounds 2 and 3 were found to be active. © 2017 The American Chemical Society and American Society of Pharmacognosy.
Address Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM), Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Observatoire Océanologique, Banyuls-sur-Mer, France
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Notes Export Date: 13 March 2017 Approved no
Call Number EcoFoG @ webmaster @ Serial 743
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Author Fox Ramos, A.E.; Alcover, C.; Evanno, L.; Maciuk, A.; Litaudon, M.; Duplais, C.; Bernadat, G.; Gallard, J.-F.; Jullian, J.-C.; Mouray, E.; Grellier, P.; Loiseau, P.M.; Pomel, S.; Poupon, E.; Champy, P.; Beniddir, M.A.
Title Revisiting Previously Investigated Plants: A Molecular Networking-Based Study of Geissospermum laeve Type Journal Article
Year 2017 Publication Journal of Natural Products Abbreviated Journal
Volume (up) 80 Issue 4 Pages 1007-1014
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Abstract Three new monoterpene indole alkaloids (1-3) have been isolated from the bark of Geissospermum laeve, together with the known alkaloids (−)-leuconolam (4), geissolosimine (5), and geissospermine (6). The structures of 1-3 were elucidated by analysis of their HRMS and NMR spectroscopic data. The absolute configuration of geissolaevine (1) was deduced from the comparison of experimental and theoretically calculated ECD spectra. The isolation workflow was guided by a molecular networking-based dereplication strategy using an in-house database of monoterpene indole alkaloids. In addition, five known compounds previously undescribed in the Geissospermum genus were dereplicated from the G. laeve alkaloid extract network and were assigned with various levels of identification confidence. The antiparasitic activities against Plasmodium falciparum and Leishmania donovani as well as the cytotoxic activity against the MRC-5 cell line were determined for compounds 1-5. © 2017 The American Chemical Society and American Society of Pharmacognosy.
Address Équipe Chimiothérapie Antiparasitaire BioCIS, Univ. Paris-Sud, CNRS, Université Paris-Saclay, 5 Rue J.-B. Clément, Châtenay-Malabry, France
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Notes Export Date: 18 May 2017 Approved no
Call Number EcoFoG @ webmaster @ Serial 752
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Author Jona Lasinio, G.; Pollice, A.; Marcon, E.; Fano, E.A.
Title Assessing the role of the spatial scale in the analysis of lagoon biodiversity. A case-study on the macrobenthic fauna of the Po River Delta Type Journal Article
Year 2017 Publication Ecological Indicators Abbreviated Journal Ecological Indicators
Volume (up) 80 Issue Pages 303-315
Keywords Biodiversity partitioning; Lagoon biodiversity; Macrobenthic fauna; Mixed effects models; Tsallis entropy
Abstract The analysis of benthic assemblages is a valuable tool to describe the ecological status of transitional water ecosystems, but species are extremely sensitive and respond to both microhabitat and seasonal differences. The identification of changes in the composition of the macrobenthic community in specific microhabitats can then be used as an “early warning” for environmental changes which may affect the economic and ecological importance of lagoons, through their provision of Ecosystem Services. From a conservational point of view, the appropriate definition of the spatial aggregation level of microhabitats or local communities is of crucial importance. The main objective of this work is to assess the role of the spatial scale in the analysis of lagoon biodiversity. First, we analyze the variation in the sample coverage for alternative aggregations of the monitoring stations in three lagoons of the Po River Delta. Then, we analyze the variation of a class of entropy indices by mixed effects models, properly accounting for the fixed effects of biotic and abiotic factors and random effects ruled by nested sources of variability corresponding to alternative definitions of local communities. Finally, we address biodiversity partitioning by a generalized diversity measure, namely the Tsallis entropy, and for alternative definitions of the local communities. The main results obtained by the proposed statistical protocol are presented, discussed and framed in the ecological context. © 2017 Elsevier Ltd
Address Dipartimento di Scienze della Vita e Biotecnologie, Università degli Studi di Ferrara, Ferrara, Italy
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Notes Export Date: 12 June 2017 Approved no
Call Number EcoFoG @ webmaster @ Serial 755
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