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Royer, M., Herbette, G., Eparvier, V., Beauchene, J., Thibaut, B., & Stien, D. (2010). Secondary metabolites of Bagassa guianensis Aubl. wood: A study of the chemotaxonomy of the Moraceae family. Phytochemistry, 71(14-15), 1708–1713.
Abstract: In order to explain the durability of the Moraceae plant family, phytochemistry of Bagassa guianensis was performed. Ethyl acetate extract was obtained from the heartwood and 18 secondary metabolites were isolated, including 6 moracins [6-O-methyl-moracin M, 6-O-methyl-moracin N and moracin Z; previously identified: moracin M, moracin N and moracin P], 8 stilbenoids [presently identified: (-)-epialboctalol and arachidin 4; previously identified: alboctalol, trans-resveratrol, arachidin 2, trans-oxyresveratrol and artogomezianol], 3 previously identified flavonoids, steppogenin, katuranin and dihydromorin, beta-sitosterol and resorcinol. Previous studies suggest that stilbenoids are responsible for the natural durability of wood. Our study has determined that B. guianensis is closely related to Morus sp. in phylogeny and should be included in the Moreae sensu stricto tribe of the Moraceae family. (C) 2010 Elsevier Ltd. All rights reserved.
Keywords: Bagassa guianensis; Moraceae; Secondary metabolites; Stilbenes; Moracins; Flavonoids; Natural durability
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Marti, G., Eparvier, V., Moretti, C., Prado, S., Grellier, P., Hue, N., et al. (2010). Antiplasmodial benzophenone derivatives from the root barks of Symphonia globulifera (Clusiaceae). Phytochemistry, 71(8-9), 964–974.
Abstract: In an effort to find antimalarial drugs, a systematic in vitro evaluation on a chloroquine-resistant strain of Plasmodium falciparum (FcB1) was undertaken on sixty plant extracts collected in French Guiana. The ethyl acetate extract obtained from the root barks of Symphonia globulifera exhibited a strong antiplasmodial activity (97% at 10 μg/ml). The phytochemical investigation of this extract led to the isolation of nine polycyclic polyprenylated acylphloroglucinol (PPAPs) compounds and two oxidized derivatives. All compounds showed antiplasmodial activity with IC(50)s ranged from 2.1 to 10.1 μM. A LC/ESI-MSn study performed on polyprenylated benzophenones previously isolated from Moronobea coccinea provided a reliable method for their detection in the extract and structural elucidation. (C) 2010 Elsevier Ltd. All rights reserved.
Keywords: Symphonia globulifera; Clusiaceae; Benzophenone; Symphonone; Antiplasmodial; LC/ESI-MS
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Bourreau, D., Aimene, Y., Beauchene, J., & Thibaut, B. (2013). Feasibility of glued laminated timber beams with tropical hardwoods. Eur. J. Wood Wood Prod., 71(5), 653–662.
Abstract: A feasibility study of glulam was carried out in French Guiana using local wood species. The aim was to determine gluing parameters affording satisfactory behaviour to manufactured glulam in a tropical climate. Three abundant wood species, with special properties, were selected for the study and resorcinol-phenol-formaldehyde resin was used for bonding. Three industrial parameters were considered: adhesive spread rate, closed assembly time and gluing pressure. Delamination and shearing tests were carried out in accordance with European Standards. The tests revealed the influence of wood properties and manufacturing parameters on joint resistance. In fact, the results showed that specific gravity and the shrinkage coefficient greatly influenced the gluing step. Indeed, wood with a medium specific gravity needed more adhesive and more pressure than wood with a high specific gravity. In addition, planing and lamella thickness were found to affect glue joint resistance. © 2013 Springer-Verlag Berlin Heidelberg.
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Lefèvre, F., Boivin, T., Bontemps, A., Courbet, F., Davi, H., Durand-Gillmann, M., et al. (2013). Considering evolutionary processes in adaptive forestry. Ann For Sci, 71(7), 723–739.
Abstract: Context: Managing forests under climate change requires adaptation. The adaptive capacity of forest tree populations is huge but not limitless. Integrating evolutionary considerations into adaptive forestry practice will enhance the capacity of managed forests to respond to climate-driven changes.
Aims: Focusing on natural regeneration systems, we propose a general framework that can be used in various and complex local situations by forest managers, in combination with their own expertise, to integrate evolutionary considerations into decision making for the emergence of an evolution-oriented forestry.
Methods: We develop a simple process-based analytical grid, using few processes and parameters, to analyse the impact of forestry practice on the evolution and evolvability of tree populations.
Results: We review qualitative and, whenever possible, quantitative expectations on the intensity of evolutionary drivers in forest trees. Then, we review the effects of actual and potential forestry practice on the evolutionary processes. We illustrate the complexity of interactions in two study cases: the evolutionary consequences for forest trees of biotic interactions and of highly heterogeneous environment.
Conclusion: Evolution-oriented forestry may contribute adapting forests to climate change. It requires combining short-term and long-term objectives. We propose future lines of research and experimentation.
Keywords: Adaptation; Climate change; Evolution-oriented forest management; Genetic resources; Silviculture
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Royer, M., Rodrigues, A. M. S., Herbette, G., Beauchene, J., Chevalier, M., Herault, B., et al. (2012). Efficacy of Bagassa guianensis Aubl. extract against wood decay and human pathogenic fungi. Int. Biodeterior. Biodegrad., 70, 55–59.
Abstract: Extractives that provide natural resistance to Bagassa guianensis Aubl. heartwood were examined. Soil-bed tests showed that the B. guianensis heartwood resistance was significantly reduced after ethyl acetate extraction, whereas methanol and especially water extractions improved the resistance. The ethyl acetate extract was submitted to a bioguided fractionation, and fractions were tested against one wood-destroying fungal strain (Pycnoporus sanguineus) and two human pathogenic fungal strains (Candida glabrata (yeast) and Trichophyton rubrum (filamentous dermatophyte)). Fraction F7, which exhibited the strongest antifungal activity, was subsequently fractionated by high performance liquid chromatography (HPLC). Six previously described compounds were isolated. Although the two moracins, 6-O-methyl-moracin N (3) and moracin N (4) were the most active against fungal strains with MIC values between 4 and 16 μg ml -1, the isolated compounds showed less or equivalent antifungal activity than the initial fraction. Possible synergism between compounds 3 and 4 and other secondary metabolites have been hypothesized. Our study demonstrated that this extract as a whole might be used as a wood preservation or antimycotic product. © 2012 Elsevier Ltd.
Keywords: Antifungal; Bagassa guianensis; Extractives; Natural durability; Polyphenols; Synergy
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Scotti, I., Montaigne, W., Cseke, K., & Traissac, S. (2013). RaBoT: A rarefaction-by-bootstrap method to compare genome-wide levels of genetic diversity. Ann. Forest Sci., 70(6), 631–635.
Abstract: Context: No efficient method is available to compare multi-locus estimates of diversity while taking into account inter-locus and inter-population stochastic variance. The advent of genome scan approaches makes the development of such tests absolutely necessary. Aims: We developed a method to compare genome-wide diversity estimates while taking into account – and factoring out – variation in census size and making use of inter-locus variance to assess significance of differences in diversity levels. Methods: An approach based on rarefaction with bootstrap re-sampling (RaBoT) was implemented into a test of multi-locus comparison of diversity coded in R. The properties of the test were studied by applying it to simulated populations with varying diversity levels and varying differences in diversity levels. The test was then applied to empirical data from disturbed and undisturbed populations of Virola michelii (Myristicaceae) genotyped at 693 amplified fragment length polymorphism (AFLP) markers. Results: RaBoT was found to be rather conservative, with large numbers of false negatives when the diversity in the compared populations was similar, and false positives mostly associated to comparisons of populations with extremely high levels of diversity. When applied to empirical data, RaBoT detected higher genetic diversity in a post-disturbance than in an undisturbed population and lower genetic diversity in a seedling than in the corresponding adult population, but it also revealed differences in diversity between subgroups within the disturbed and undisturbed plots. Conclusion: RaBoT is a sensitive method to compare multi-locus levels of diversity that can be applied both at the genotype level for dominant markers (e.g. AFLP) and at the allele level for biallelic codominant markers (e.g. single-nucleotide polymorphisms). © 2013 INRA and Springer-Verlag France.
Keywords: Diversity comparison; Genome scan; Genome-level diversity; Population genetics; Statistical testing
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Clair, B., Alteyrac, J., Gronvold, A., Espejo, J., Chanson, B., & Alméras, T. (2013). Patterns of longitudinal and tangential maturation stresses in Eucalyptus nitens plantation trees. Ann. Forest Sci., 70(8), 801–811.
Abstract: Context: Tree orientation is controlled by asymmetric mechanical stresses set during wood maturation. The magnitude of maturation stress differs between longitudinal and tangential directions, and between normal and tension woods. Aims: We aimed at evaluating patterns of maturation stress on eucalypt plantation trees and their relation with growth, with a focus on tangential stress evaluation. Methods: Released maturation strains along longitudinal and tangential directions were measured around the circumference of 29 Eucalyptus nitens trees, including both straight and leaning trees. Results: Most trees produced asymmetric patterns of longitudinal maturation strain, but more than half of the maturation strain variability occurred between trees. Many trees produced high longitudinal tensile stress all around their circumference. High longitudinal tensile stress was not systematically associated with the presence of gelatinous layer. The average magnitude of released longitudinal maturation strain was found negatively correlated to the growth rate. A methodology is proposed to ensure reliable evaluation of released maturation strain in both longitudinal and tangential directions. Tangential strain evaluated with this method was lower than previously reported. Conclusion: The stress was always tensile along the longitudinal direction and compressive along the tangential direction, and their respective magnitude was positively correlated. This correlation does not result from a Poisson effect but may be related to the mechanism of maturation stress generation. © 2013 # The Author(s) 2013. This article is published with open access at Springerlink.com.
Keywords: Eucalyptus nitens; G-layer; Longitudinal maturation stress; Maturation strain; Tangential maturation stress; Tension wood
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Marcon, E. (2019). Entropy as a common measure of biodiversity and the spatial structure of economic activity. Rev. Econ., 70(3), 305–326.
Abstract: Measures of spatial concentration and specialization in economics are similar to those of biodiversity and ubiquity of species in ecology. Entropy is the fundamental tool that originated in statistical physics and information theory. The definition of number equivalents or effective numbers, that is the number of types in an ideal, simplified distribution, is introduced along with the partitioning of the joint diversity of a bi-dimensional distribution into absolute and relative concentration or specialization and replication. The whole framework is theoretically robust and allows measuring the spatial structure of a discrete space.
Keywords: Diversity; Economic geography; Spatial concentration; Specialization
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Stien, D., & Gastaldi, S. (2004). Design of polyaromatic hydrocarbon-supported tin reagents: A new family of tin reagents easily removable from reaction mixtures. J. Org. Chem., 69(13), 4464–4470.
Abstract: We report in this paper the preparation and use of stannanes 11, 12a, and 12b, compounds whose 3-pyrenylpropyl side chain affinity for activated carbon simplifies tin removal and product isolation. Our pyrene-supported reagents can be used for radical reductions and cyclizations (11), radical and cationic allylations (12a), and Stille couplings (12b) in much the same way as tributyltin derivatives.
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Brémaud, I., El Kaïm, Y., Guibal, D., Minato, K., Thibaut, B., & Gril, J. (2012). Characterisation and categorisation of the diversity in viscoelastic vibrational properties between 98 wood types. Ann. Forest Sci., 69(3), 373–386.
Abstract: · Context Increased knowledge on diversity in wood properties would have implications both for fundamental research and for promoting a diversification of uses as material. · Aims The objective is to contribute to overcoming the critical lack of data on the diversity of wood dynamic mechanical/viscoelastic vibrational properties by testing lesser known species and categorising sources of variability. · Methods Air-dry axial specific dynamic modulus of elasticity (E′/γ) and damping coefficient (tand) were measured on a wide sampling (1,792 specimens) of 98 wood types from 79 species. An experimental device and protocol was designed for conducting systematic (i.e. rapid and reproducible) characterisations. · Results Diversity at the specimens' level corroborates the “standard” relationship between tanδ and E'/γ, which is discussed in terms of orientation of wood elements and of chemical composition. Diversity at the species level is expressed on the basis of results for normal heartwood, with specific gravity (γ) ranging from 0.2 to 1.3. Axial E'/γ ranges from 9 to 32 GPa and tand from 4×10 -3 to 19×10 -3. Properties distribution follows a continuum, but with group characteristics. The lowest values of tanδ are only found in certain tropical hardwoods. Results can also suggest alternative species for musical instruments making. · Conclusion The variations in specific gravity, in stiffness or in “viscosity” appear to be predominantly linked to different levels of diversity: between species or between wood types (reaction wood or taxonomy-related differences in heartwood extractives). © INRA/Springer-Verlag France 2011.
Keywords: Damping coefficient; Dynamic mechanical properties; Specific dynamic modulus of elasticity; Specific gravity; Viscoelastic vibrational properties; Wood diversity
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