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Author Brémaud, I.; Ruelle, J.; Thibaut, A.; Thibaut, B. doi  openurl
  Title Changes in viscoelastic vibrational properties between compression and normal wood: Roles of microfibril angle and of lignin Type Journal Article
  Year 2013 Publication Holzforschung Abbreviated Journal  
  Volume 67 Issue 1 Pages 75-85  
  Keywords Compression wood (CW); Damping coefficient; Ft-Ir; Internal friction; Lignin; Microfibril angle (MFA); Picea abies; Pinus pinaster; Pinus sylvestris; Specific dynamic modulus of elasticity; Viscoelastic vibrational properties  
  Abstract This study aims at better understanding the respective influences of specific gravity (γ ), microfibril angle (MFA), and cell wall matrix polymers on viscoelastic vibrational properties of wood in the axial direction. The wide variations of properties between normal wood (NW) and compression wood (CW) are in focus. Three young bent trees (Picea abies, Pinus sylvestris and Pinus pinaster ), which recovered verticality, were sampled. Several observed differences between NW and CW were highly significant in terms of anatomical, physical (γ, shrinkage, CIE Lab colorimetry), mechanical (compressive strength), and vibrational properties. The specific dynamic modulus of elasticity (E′/γ) decreases with increasing MFA, and Young's modulus (E′) can be satisfactorily explained by γ and MFA. Apparently, the type of the cell wall polymer matrix is not influential in this regard. The damping coefficient (tan δ) does not depend solely on the MFA of NW and CW. The tanδ-E′/γ relationship evidences that, at equivalent E′/γ, the tan δ of CW is approximately 34% lower than that of NW. This observation is ascribed to the more condensed nature of CW lignins, and this is discussed in the context of previous findings in other hygrothermal and time/frequency domains. It is proposed that the lignin structure and the amount and type of extractives, which are both different in various species, are partly responsible for taxonomy-related damping characteristics. Copyright © by Walter de Gruyter • Berlin • Boston.  
  Address Wood Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland  
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  Notes (down) Export Date: 25 February 2013; Source: Scopus Approved no  
  Call Number EcoFoG @ webmaster @ Serial 471  
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Author Barantal, S.; Schimann, H.; Fromin, N.; Hättenschwiler, S. url  openurl
  Title C, N and P fertilization in an Amazonian rainforest supports stoichiometric dissimilarity as a driver of litter diversity effects on decomposition Type Journal Article
  Year 2014 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proceedings. Biological sciences / The Royal Society  
  Volume 281 Issue 1796 Pages 20141682  
  Keywords litter diversity; neotropical forest; nutrient addition; soil fauna; stoichiometry; trait dissimilarity  
  Abstract Plant leaf litter generally decomposes faster as a group of different species than when individual species decompose alone, but underlying mechanisms of these diversity effects remain poorly understood. Because resource C : N : P stoichiometry (i.e. the ratios of these key elements) exhibits strong control on consumers, we supposed that stoichiometric dissimilarity of litter mixtures (i.e. the divergence in C : N : P ratios among species) improves resource complementarity to decomposers leading to faster mixture decomposition. We tested this hypothesis with: (i) a wide range of leaf litter mixtures of neotropical tree species varying in C : N : P dissimilarity, and (ii) a nutrient addition experiment (C, N and P) to create stoichiometric similarity. Litter mixtures decomposed in the field using two different types of litterbags allowing or preventing access to soil fauna. Litter mixture mass loss was higher than expected from species decomposing singly, especially in presence of soil fauna. With fauna, synergistic litter mixture effects increased with increasing stoichiometric dissimilarity of litter mixtures and this positive relationship disappeared with fertilizer addition. Our results indicate that litter stoichiometric dissimilarity drives mixture effects via the nutritional requirements of soil fauna. Incorporating ecological stoichiometry in biodiversity research allows refinement of the underlying mechanisms of how changing biodiversity affects ecosystem functioning. © 2014 The Author(s) Published by the Royal Society. All rights reserved.  
  Address Centre d'Ecologie Fonctionnelle et Evolutive (CEFE UMR 5175, CNRS-Université de Montpellier-Université Paul-Valéry Montpellier-EPHE), 1919 Route de MENDE, 34293 Montpellier Cedex 5, France  
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  Notes (down) Export Date: 24 July 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 613  
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Author Lamarre, G.P.A.; Mendoza, I.; Fine, P.V.A.; Baraloto, C. url  openurl
  Title Leaf synchrony and insect herbivory among tropical tree habitat specialists Type Journal Article
  Year 2014 Publication Plant Ecology Abbreviated Journal Plant Ecol.  
  Volume 215 Issue 2 Pages 209-220  
  Keywords Escape; French Guiana; Herbivorous insects; Phenology; Resource availability; Time lag  
  Abstract Growth defense tradeoff theory predicts that plants in low-resource habitats invest more energy in defense mechanisms against natural enemies than growth, whereas plants in high-resource habitats can afford higher leaf loss rates. A less-studied defense against herbivores involves the synchrony of leaf production, which can be an effective defense strategy if leaf biomass production exceeds the capacity of consumption by insects. The aim of this study was to determine whether leaf synchrony varied across habitats with different available resources and whether insects were able to track young leaf production among tree habitat specialists in a tropical forest of French Guiana. We predicted that high-resource habitats would exhibit more synchrony in leaf production due to the low cost and investment to replace leaf tissue. We also expected closer patterns of leaf synchrony and herbivory within related species, assuming that they shared herbivores. We simultaneously monitored leaf production and herbivory rates of five pairs of tree species, each composed of a specialist of terra firme or white-sand forests within the same lineage. Our prediction was not supported by the strong interaction of habitat and lineage for leaf synchrony within individuals of the same species; although habitat specialists differed in leaf synchrony within four of five lineages, the direction of the effect was variable. All species showed short time lags for the correlation between leaf production and herbivory, suggesting that insects are tightly tracking leaf production, especially for the most synchronous species. Leaf synchrony may provide an important escape defense against herbivores, and its expression appears to be constrained by both evolutionary history and environmental factors. © 2014 Springer Science+Business Media Dordrecht.  
  Address Department of Biology, University of Florida, Gainesville, FL, 32611, United States  
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  Notes (down) Export Date: 24 February 2014; Source: Scopus; Coden: Plecf; Language of Original Document: English; Correspondence Address: Lamarre, G. P. A.; Université Antilles Guyane, UMR Ecologie des Forêts de Guyane, 97310 Kourou, French Guiana; email: greglamarre973@gmail.com; Funding Details: DEB-0743103/0743800, NSF, National Science Foundation Approved no  
  Call Number EcoFoG @ webmaster @ Serial 530  
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Author Anouhe, J.-B.S.; Adima, A.A.; Niamké, F.B.; Stien, D.; Amian, B.K.; Blandinieres, P.-A.; Virieux, D.; Pirat, J.-L.; Kati-Coulibaly, S.; Amusant, N. url  openurl
  Title Dicorynamine and harmalan-N-oxide, two new β-carboline alkaloids from Dicorynia guianensis Amsh heartwood Type Journal Article
  Year 2015 Publication Phytochemistry Letters Abbreviated Journal Phytochemistry Letters  
  Volume 12 Issue Pages 158-163  
  Keywords ABTS antioxidant; Biogenesis; Dicorynia guianensis; Nitrone; Spiroindolone  
  Abstract Abstract The chemical investigations of Dicorynia guianensis heartwood led to the isolation of four new indole alkaloids for the first time in this plant. Compound (1) identified as spiroindolone 2′,3′,4′,9′-tetrahydrospiro [indoline-3,1′pyrido[3,4-b]-indol]-2-one, and compound (3) described as nitrone 1-methyl-4,9-dihydro-3H-pyrido [3,4-b] indole 2-oxide and were isolated for the first time as natural products. ABTS antioxidant activity guided their isolation. © 2015 Published by Elsevier B.V. on behalf of Phytochemical Society of Europe.  
  Address CIRAD, Département Environnements et Sociétés, UMR Ecologie des Forêts de GuyaneKourou cedex, France  
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  Notes (down) Export Date: 24 April 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 598  
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Author Touchard, A.; Koh, J.M.S.; Aili, S.R.; Dejean, A.; Nicholson, G.M.; Orivel, J.; Escoubas, P. url  openurl
  Title The complexity and structural diversity of ant venom peptidomes is revealed by mass spectrometry profiling Type Journal Article
  Year 2015 Publication Rapid Communications in Mass Spectrometry Abbreviated Journal Rapid Communications in Mass Spectrometry  
  Volume 29 Issue 5 Pages 385-396  
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  Abstract Rationale Compared with other animal venoms, ant venoms remain little explored. Ants have evolved complex venoms to rapidly immobilize arthropod prey and to protect their colonies from predators and pathogens. Many ants have retained peptide-rich venoms that are similar to those of other arthropod groups. Methods With the goal of conducting a broad and comprehensive survey of ant venom peptide diversity, we investigated the peptide composition of venoms from 82 stinging ant species from nine subfamilies using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS). We also conducted an in-depth investigation of eight venoms using reversed-phase high-performance liquid chromatography (RP-HPLC) separation coupled with offline MALDI-TOFMS. Results Our results reveal that the peptide compositions of ant venom peptidomes from both poneroid and formicoid ant clades comprise hundreds of small peptides (<4 kDa), while large peptides (>4 kDa) are also present in the venom of formicoids. Chemical reduction revealed the presence of disulfide-linked peptides in most ant subfamilies, including peptides structured by one, two or three disulfide bonds as well as dimeric peptides reticulated by three disulfide bonds. Conclusions The biochemical complexity of ant venoms, associated with an enormous ecological and taxonomic diversity, suggests that stinging ant venoms constitute a promising source of bioactive molecules that could be exploited in the search for novel drug and biopesticide leads. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.  
  Address VenomeTech, 473 Route des DolinesValbonne, France  
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  Notes (down) Export Date: 24 April 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 599  
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Author Le Guen, R.; Corbara, B.; Rossi, V.; Azémar, F.; Dejean, A. url  openurl
  Title Reciprocal protection from natural enemies in an ant-wasp association Type Journal Article
  Year 2015 Publication Comptes Rendus – Biologies Abbreviated Journal Comptes Rendus – Biologies  
  Volume 338 Issue 4 Pages 255-259  
  Keywords Aggressiveness; Arboreal ants; Azteca; Polybia; Protection mutualism; Social wasps  
  Abstract Abstract We show that in French Guiana the large carton nests of Azteca chartifex, a territorially-dominant arboreal dolichoderine ant, are protected from bird attacks when this ant lives in association with Polybia rejecta, an epiponine social wasp. Because A. chartifex colonies are well known for their ability to divert army ant raids from the base of their host tree so that they protect their associated wasps from these raids, there is a reciprocal benefit for these two partners, permitting us to call this association a mutualism. We also show that P. rejecta nests are significantly less often attacked by birds than are those of two compared epiponine social wasp species. Furthermore, experimentation using a standardized protocol demonstrated the significantly higher aggressiveness of P. rejecta compared to seven other wasp species. We conclude that the efficacious protection of its associated ant nests is likely due to the extreme aggressiveness of P. rejecta. © 2015 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.  
  Address CNRS, Écologie des forêts de Guyane (UMR-CNRS 8172), Campus agronomique, BP 316Kourou cedex, France  
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  Notes (down) Export Date: 24 April 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 600  
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Author Ntienoue, J.K.; Reguer, A.; Robert, F.; Nait-Rabah, O.; Roos, C. pdf  url
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  Title Electrochemical behaviour of a super austenitic stainless steel in amazonian aqueous environment Type Journal Article
  Year 2013 Publication International Journal of Electrochemical Science Abbreviated Journal Int.J.Electrochem.Sci.  
  Volume 8 Issue 4 Pages 4761-4775  
  Keywords Cyclic voltammetry; Eis; Esem; Passive films; Stainless steel  
  Abstract The electrochemical behaviour of 254 SMO super austenitic stainless steel in natural seawater collected from river mouth of French Guiana was investigated. A comparative study of samples immersed during 22 days in this environment was made including influences of scraped biofilm introduced in experiments and of stirring. Electrochemical measurements – open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and linear polarisation (LP) – are used to characterize the metal/medium interface included biofilms adhesion. The EDX analysis (EDAX system) shows that the chemical composition of adhered biofilm consists mostly of iron, oxygen, silicon and aluminium and seem preferentially bind on metal defects. © 2013 by ESG.  
  Address Laboratoire Matériaux et Molécules en Milieu Amazonien, Université des Antilles et de la Guyane, UAG-UMR ECOFOG, Campus Trou Biran, Cayenne 97337, French Guiana  
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  Notes (down) Export Date: 24 April 2013; Source: Scopus; Language of Original Document: English; Correspondence Address: Roos, C.; Laboratoire Matériaux et Molécules en Milieu Amazonien, Université des Antilles et de la Guyane, UAG-UMR ECOFOG, Campus Trou Biran, Cayenne 97337, French Guiana; email: christophe.roos@guyane.univ-ag.fr Approved no  
  Call Number EcoFoG @ webmaster @ Serial 483  
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Author Baraloto, C.; Hardy, O.J.; Paine, C.E.T.; Dexter, K.G.; Cruaud, C.; Dunning, L.T.; Gonzalez, M.-A.; Molino, J.-F.; Sabatier, D.; Savolainen, V.; Chave, J. url  openurl
  Title Using functional traits and phylogenetic trees to examine the assembly of tropical tree communities Type Journal Article
  Year 2012 Publication Journal of Ecology Abbreviated Journal J. Ecol.  
  Volume 100 Issue 3 Pages 690-701  
  Keywords Competition; Determinants of plant community diversity and structure; Environmental filtering; French Guiana; Functional traits; Limiting similarity; Niche; Phylogenetic signal; Tropical forests  
  Abstract Niche theory proposes that species differences underlie both coexistence within communities and the differentiation in species composition among communities via limiting similarity and environmental filtering. However, it has been difficult to extend niche theory to species-rich communities because of the empirical challenge of quantifying niches for many species. This has motivated the development of functional and phylogeny-based approaches in community ecology, which represent two different means of approximating niche attributes. Here, we assess the utility of plant functional traits and phylogenetic relationships in predicting community assembly processes using the largest trait and phylogenetic data base to date for any set of species-rich communities. We measured 17 functional traits for all 4672 individuals of 668 tree species co-occurring in nine tropical rain forest plots in French Guiana. Trait variation was summarized into two ordination axes that reflect species niche overlap. We also generated a dated molecular phylogenetic tree based on DNA sequencing of two plastid loci (rbcL and matK) comprising 97% of the individuals and 91% of the species in the plots. We found that, on average, co-occurring species had greater functional and, to a lesser extent, phylogenetic similarity than expected by chance. We also found that functional traits and their ordination loadings showed significant, albeit weak, phylogenetic signal, suggesting that phylogenetic distance provides pertinent information on niche overlap in tropical tree communities. Synthesis. We provide the most comprehensive examination to date of the relative importance of environmental filtering and limiting similarity in structuring tropical tree communities. Our results confirm that environmental filtering is the overriding influence on community assembly in these species-rich systems. © 2012 The Authors. Journal of Ecology © 2012 British Ecological Society.  
  Address Royal Botanic Gardens, Kew, Richmond TW9 3DS, United Kingdom  
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  Notes (down) Export Date: 24 April 2012; Source: Scopus; Coden: Jecoa; doi: 10.1111/j.1365-2745.2012.01966.x; Language of Original Document: English; Correspondence Address: Chave, J.; Université Paul Sabatier, CNRS, UMR 5174 Laboratoire Evolution et Diversité Biologique, 31062 Toulouse, France; email: chave@cict.fr Approved no  
  Call Number EcoFoG @ webmaster @ Serial 393  
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Author Tindo, M.; Mbenoun Masse, P.S.; Kenne, M.; Mony, R.; Orivel, J.; Doumtsop Fotio, A.; Fotso Kuaté, A.; Djiéto-Lordon, C.; Fomena, A.; Estoup, A.; Dejean, A.; Foucaud, J. url  openurl
  Title Current distribution and population dynamics of the little fire ant supercolony in cameroon Type Journal Article
  Year 2012 Publication Insectes Sociaux Abbreviated Journal Insectes Sociaux  
  Volume 59 Issue 2 Pages 175-182  
  Keywords Auropunctata; Dispersion; Invasive ants; Reproduction strategy; Unicoloniality; Wasmannia  
  Abstract The little fire ant, Wasmannia auropunctata, is native to Central America, but has been introduced into many parts of the world. We examined the current distribution of W. auropunctata in Cameroon, tested for aggression between workers from different parts of the country, and examined the genotypes of workers, queens, and males to evaluate the mating system. We found W. auropunctata at 36 sites in three provinces (Centre, East, and South). We found W. auropunctata only in human-disturbed habitats. Its spread appears to be primarily human mediated. Aggressive behaviour was almost non-existent between workers from different sites, indicating that there is only one supercolony in Cameroon. Our genetic analysis found that only one male/female pair of clones was introduced into Cameroon, probably from Gabon. No new male clonal lineage was identified, whereas new sexually derived female clonal lineages were noted. Apart from the genotype of the founding queen, which was well distributed but generally not dominant, a new clonal queen genotype emerged and was both omnipresent and dominant at most sites. These results may be useful in the development of management strategies. © International Union for the Study of Social Insects (IUSSI) 2011.  
  Address Laboratoire Evolution Genome Speciation, Centre National de la Recherche Scientifique, Avenue de la Terrasse, F 91198 Gif sur Yvette, France  
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  Notes (down) Export Date: 24 April 2012; Source: Scopus; Coden: Insoa; doi: 10.1007/s00040-011-0202-x; Language of Original Document: English; Correspondence Address: Tindo, M.; Département de Biologie des Organismes Animaux, Faculté des Sciences, Université de Douala, BP 24157 Douala, Cameroon; email: tindodouala@yahoo.com Approved no  
  Call Number EcoFoG @ webmaster @ Serial 392  
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Author Bertani, S.; Houel, E.; Jullian, V.; Bourdy, G.; Valentin, A.; Stien, D.; Deharo, E. url  openurl
  Title New findings on Simalikalactone D, an antimalarial compound from Quassia amara L. (Simaroubaceae) Type Journal Article
  Year 2012 Publication Experimental Parasitology Abbreviated Journal Exp. Parasitol.  
  Volume 130 Issue 4 Pages 341-347  
  Keywords Antimalarial; Plasmodium; Quassia amara; Quassinoid; Simalikalactone d  
  Abstract Quassia amara L. (Simaroubaceae) is a species widely used as tonic and is claimed to be an efficient antimalarial all over the Northern part of the Amazon basin. Quassinoid compound Simalikalactone D (SkD) has been shown to be one of the molecules responsible for the antiplasmodial activity of a watery preparation made out of juvenile fresh leaves of this plant. Because of its strong antimalarial activity, we decided to have a further insight of SkD pharmacological properties, alone or in association with classical antimalarials. At concentrations of up to 200 μM, we showed herein that SkD did not exert any apoptotic or necrotic activities in vitro on lymphoblastic cells. However, an antiproliferative effect was evident at concentrations higher than 45. nM. SkD was inefficient at inhibiting heme biomineralization and the new permeability pathways induced by the parasite in the host erythrocyte membrane. With respect to Plasmodium falciparum erythrocytic stages, SkD was almost inactive on earlier and later parasite stages, but potently active at the 30th h of parasite cycle when DNA replicates in mature trophozoites. In vitro combination studies with conventional antimalarial drugs showed that SkD synergizes with atovaquone (ATO). The activity of ATO on the Plasmodium mitochondrial membrane potential was enhanced by SkD, which on its own had a poor effect on this cellular parameter. © 2012 Elsevier Inc.  
  Address UMR152 IRD-UPS, Institut de Recherche pour le Développement (IRD), Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru  
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  Notes (down) Export Date: 24 April 2012; Source: Scopus; Coden: Expaa; doi: 10.1016/j.exppara.2012.02.013; Language of Original Document: English; Correspondence Address: Deharo, E.; UMR152 IRD-UPS, Faculté de Pharmacie, 35 chemin des maraîchers, 31062 Toulouse cedex 9, France; email: ericdeharo@gmail.com Approved no  
  Call Number EcoFoG @ webmaster @ Serial 395  
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