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Author Almeras, T.; Derycke, M.; Jaouen, G.; Beauchene, J.; Fournier, M.
Title Functional diversity in gravitropic reaction among tropical seedlings in relation to ecological and developmental traits Type Journal Article
Year 2009 Publication Journal of Experimental Botany Abbreviated Journal J. Exp. Bot.
Volume 60 Issue 15 Pages 4397-4410
Keywords Biomechanics; French Guiana; functional diversity; gravitropism; reaction wood; tropical rainforest
Abstract Gravitropism is necessary for plants to control the orientation of their axes while they grow in height. In woody plants, stem re-orientations are costly because they are achieved through diameter growth. The functional diversity of gravitropism was studied to check if the mechanisms involved and their efficiency may contribute to the differentiation of height growth strategies between forest tree species at the seedling stage. Seedlings of eight tropical species were grown tilted in a greenhouse, and their up-righting movement and diameter growth were measured over three months. Morphological, anatomical, and biomechanical traits were measured at the end of the survey. Curvature analysis was used to analyse the up-righting response along the stems. Variations in stem curvature depend on diameter growth, size effects, the increase in self-weight, and the efficiency of the gravitropic reaction. A biomechanical model was used to separate these contributions. Results showed that (i) gravitropic movements were based on a common mechanism associated to similar dynamic patterns, (ii) clear differences in efficiency (defined as the change in curvature achieved during an elementary diameter increment for a given stem diameter) existed between species, (iii) the equilibrium angle of the stem and the anatomical characters associated with the efficiency of the reaction also differed between species, and (iv) the differences in gravitropic reaction were related to the light requirements: heliophilic species, compared to more shade-tolerant species, had a larger efficiency and an equilibrium angle closer to vertical. This suggests that traits determining the gravitropic reaction are related to the strategy of light interception and may contribute to the differentiation of ecological strategies promoting the maintenance of biodiversity in tropical rainforests.
Address (down) [Almeras, Tancrede; Derycke, Morgane; Jaouen, Gaelle] INRA, UMR Ecol Forets Guyane, F-97310 Kourou, France, Email: t_almeras@hotmail.com
Corporate Author Thesis
Publisher OXFORD UNIV PRESS Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-0957 ISBN Medium
Area Expedition Conference
Notes ISI:000271389400017 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 96
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Author Almeras, T.; Fournier, M.
Title Biomechanical design and long-term stability of trees: Morphological and wood traits involved in the balance between weight increase and the gravitropic reaction Type Journal Article
Year 2009 Publication Journal of Theoretical Biology Abbreviated Journal J. Theor. Biol.
Volume 256 Issue 3 Pages 370-381
Keywords Mechanical design; Gravitropism; Bending stresses; Allometry; Reaction wood
Abstract Studies on tree biomechanical design usually focus on stem stiffness, resistance to breakage or uprooting, and elastic stability. Here we consider another biomechanical constraint related to the interaction between growth and gravity. Because stems are slender structures and are never perfectly symmetric, the increase in tree mass always causes bending movements. Given the current mechanical design of trees, integration of these movements over time would ultimately lead to a weeping habit unless some gravitropic correction occurs. This correction is achieved by asymmetric internal forces induced during the maturation of new wood. The long-term stability of a growing stem therefore depends on how the gravitropic correction that is generated by diameter growth balances the disturbance due to increasing self weight. General mechanical formulations based on beam theory are proposed to model these phenomena. The rates of disturbance and correction associated with a growth increment are deduced and expressed as a function of elementary traits of stem morphology, cross-section anatomy and wood properties. Evaluation of these traits using previously published data shows that the balance between the correction and the disturbance strongly depends on the efficiency of the gravitropic correction, which depends on the asymmetry of wood maturation strain, eccentric growth, and gradients in wood stiffness. By combining disturbance and correction rates, the gravitropic performance indicates the dynamics of stem bending during growth. It depends on stem biomechanical traits and dimensions. By analyzing dimensional effects, we show that the necessity for gravitropic correction might constrain stem allometric growth in the long-term. This constraint is compared to the requirement for elastic stability, showing that gravitropic performance limits the increase in height of tilted stem and branches. The performance of this function may thus limit the slenderness and lean of stems, and therefore the ability of the tree to capture light in a heterogeneous environment. (c) 2008 Elsevier Ltd. All rights reserved.
Address (down) [Almeras, T.; Fournier, M.] INRA, UMR Ecol Forets Guyane, F-97310 Kourou, France, Email: t_almeras@hotmail.com
Corporate Author Thesis
Publisher ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-5193 ISBN Medium
Area Expedition Conference
Notes ISI:000263077100008 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 123
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Author Aimene, Y.; Vidal-Salle, E.; Hagege, B.; Sidoroff, F.; Boisse, P.
Title A Hyperelastic Approach for Composite Reinforcement Large Deformation Analysis Type Journal Article
Year 2010 Publication Journal of Composite Materials Abbreviated Journal J. Compos Mater.
Volume 44 Issue 1 Pages 5-26
Keywords hyperelasticity; woven reinforcements; forming; fabric mechanical behavior; finite element
Abstract A hyperelastic constitutive model is developed for textile composite reinforcement at large strain. A potential is proposed, which is the addition of two tension and one shear energies. The proposed potential is a function of the right Cauchy Green and structural tensor invariants whose choice corresponds to textile composite reinforcement mechanical behavior which exhibits weak elongations in the fiber directions and large angular variations in the fabric plane. The model is implemented in a Vumat user routine of ABAQUS/Explicit. Some elementary tests are performed in order to identify the model and verify its validity. It is then used to simulate the hemispherical punch forming of balanced and unbalanced fabrics. A correct agreement is obtained with experimental forming processes.
Address (down) [Aimene, Y.; Vidal-Salle, E.; Boisse, P.] Univ Lyon, INSA Lyon, LaMCoS, F-69621 Villeurbanne, France, Email: philippe.boisse@insa-lyon.fr
Corporate Author Thesis
Publisher SAGE PUBLICATIONS LTD Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9983 ISBN Medium
Area Expedition Conference
Notes ISI:000273509100001 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 84
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Author Aimene, Y.E.; Nairn, J.A.
Title Simulation of transverse wood compression using a large-deformation, hyperelastic–plastic material model Type Journal Article
Year 2015 Publication Wood Science and Technology Abbreviated Journal Wood Science and Technology
Volume 49 Issue 1 Pages 21-39
Keywords
Abstract Transverse compression of wood is a process that induces large deformations. The process is dominated by elastic and plastic cell wall buckling. This work reports a numerical study of the transverse compression and densification of wood using a large-deformation, elastic–plastic constitutive law. The model is isotropic, formulated within the framework of hyperelasticity, and implemented in explicit material point method (MPM) software. The model was first validated for modeling of cellular materials by compression of an isotropic cellular model specimen. Next, it was used to model compression of wood by first validating use of isotropic, transverse plane properties for tangential compression of hardwood, and then by investigating both tangential and radial compression of softwood. Importantly, the discretization of wood specimens used MPM methods to reproduce accurately the complex morphology of wood anatomy for different species. The simulations have reproduced observations of stress–strain response during wood compression including details of inhomogeneous deformation caused by variations in wood anatomy. © 2014, Springer-Verlag Berlin Heidelberg.
Address (down) Wood Science and Engineering Department, Oregon State University, Corvallis, OR, United States
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Notes Export Date: 27 August 2015 Approved no
Call Number EcoFoG @ webmaster @ Serial 617
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Author Brémaud, I.; Ruelle, J.; Thibaut, A.; Thibaut, B.
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 (down) Wood Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
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Notes Export Date: 25 February 2013; Source: Scopus Approved no
Call Number EcoFoG @ webmaster @ Serial 471
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Author Brémaud, I.; El Kaïm, Y.; Guibal, D.; Minato, K.; Thibaut, B.; Gril, J.
Title Characterisation and categorisation of the diversity in viscoelastic vibrational properties between 98 wood types Type Journal Article
Year 2012 Publication Annals of Forest Science Abbreviated Journal Ann. Forest Sci.
Volume 69 Issue 3 Pages 373-386
Keywords Damping coefficient; Dynamic mechanical properties; Specific dynamic modulus of elasticity; Specific gravity; Viscoelastic vibrational properties; Wood diversity
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.
Address (down) Wood Laboratory, EMPA, Überlandstrasse 129, 8600 Dübendorf, Switzerland
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ISSN 12864560 (Issn) ISBN Medium
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Notes Export Date: 20 June 2012; Source: Scopus; Coden: Afosf; doi: 10.1007/s13595-011-0166-z; Language of Original Document: English; Correspondence Address: Brémaud, I.; Wood Laboratory, EMPA, Überlandstrasse 129, 8600 Dübendorf, Switzerland; email: iris_bremaud@hotmail.com Approved no
Call Number EcoFoG @ webmaster @ Serial 403
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Author Siebicke, L.; Hunner, M.; Foken, T.
Title Aspects of CO 2 advection measurements Type Journal Article
Year 2012 Publication Theoretical and Applied Climatology Abbreviated Journal Theor. Appl. Climatol.
Volume 109 Issue 1-2 Pages 109-131
Keywords
Abstract Observations of vegetation-atmosphere exchange of carbon dioxide (CO 2) by the eddy covariance (EC) technique are limited by difficult conditions such as nighttime and heterogeneous terrain. Thus, advective flux components are included into the net ecosystem exchange (NEE) budget. However, advection measurements are experimentally challenging and do not always help to solve the night flux problem of the EC technique. This study investigates alternative methods for the observation of horizontal advection, in particular horizontal concentration gradients, as well as different approaches to coordinate rotation and vertical advection. Continuous high-frequency measurements of the horizontal CO 2 concentration field are employed and compared to the often used discontinuous sequential sampling. Significant differences were found in the case of 30-min mean concentration values between the conventional discontinuous sampling approach and the complete observation of the time series by continuous sampling. Estimates of vertical advection rely on accurate estimates of vertical wind velocity (W). Therefore, different approaches to the planar fit coordinate rotation have been investigated. Sector-wise rotation was able to eliminate directional dependencies of mean W. Furthermore, the effect of the data set length used for rotation (window length) was investigated and was found to have significant impact on estimates of vertical advection, with larger window lengths yielding about 50% larger vertical advection. A sequential planar fit with controlled window length is proposed to give reproducible results. The different approaches to the measurement and calculation of horizontal and vertical advection presented are applied to data obtained during the exchange processes in mountainous region experiment at the FLUXNET site Waldstein-Weidenbrunnen (DE-Bay). Estimates of NEE including advection are compared to NEE from turbulent and storage flux alone without advection. NEE including vertical advection with sector-wise planar fit rotation and controlled window length and including horizontal advection from continuous gradient measurements, which were comprehensively bias corrected by a new approach, did compare well with the expected night flux error, with meteorological drivers of the fluxes and with soil chamber measurements. Unrealistically large and noisy values of horizontal advection from the conventional discontinuous sampling approach, which lead to unrealistic values of NEE, could be eliminated by the alternative approaches presented. We therefore suggest the further testing of those approaches at other sites in order to improve the accuracy of advection measurements and, subsequently, estimates of NEE. © 2011 Springer-Verlag.
Address (down) Wind Cert Services, TÜV SÜD Industrie Service GmbH, Ludwig-Eckert-Str. 10, 93049 Regensburg, Germany
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ISSN 0177798x (Issn) ISBN Medium
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Notes Export Date: 27 June 2012; Source: Scopus; doi: 10.1007/s00704-011-0552-3; Language of Original Document: English; Correspondence Address: Siebicke, L.; Department of Micrometeorology, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany; email: lukas.siebicke@uni-bayreuth.de Approved no
Call Number EcoFoG @ webmaster @ Serial 406
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Author Touchard, A.; Koh, J.M.S.; Aili, S.R.; Dejean, A.; Nicholson, G.M.; Orivel, J.; Escoubas, P.
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
Keywords
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 (down) VenomeTech, 473 Route des DolinesValbonne, France
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Notes Export Date: 24 April 2015 Approved no
Call Number EcoFoG @ webmaster @ Serial 599
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Author Touchard, A.; Brust, A.; Cardoso, F.C.; Chin, Y.K.-Y.; Herzig, V.; Jin, A.-H.; Dejean, A.; Alewood, P.F.; King, G.F.; Orivel, J.; Escoubas, P.
Title Isolation and characterization of a structurally unique β-hairpin venom peptide from the predatory ant Anochetus emarginatus Type Journal Article
Year 2016 Publication Biochimica et Biophysica Acta – General Subjects Abbreviated Journal Biochimica et Biophysica Acta – General Subjects
Volume 1860 Issue 11 Pages 2553-2562
Keywords Anochetus; Ant venom; Disulfide-rich peptides; L-type calcium channels; Neurotoxin; Poneritoxins; U1-PONTX-Ae1a
Abstract Background Most ant venoms consist predominantly of small linear peptides, although some contain disulfide-linked peptides as minor components. However, in striking contrast to other ant species, some Anochetus venoms are composed primarily of disulfide-rich peptides. In this study, we investigated the venom of the ant Anochetus emarginatus with the aim of exploring these novel disulfide-rich peptides. Methods The venom peptidome was initially investigated using a combination of reversed-phase HPLC and mass spectrometry, then the amino acid sequences of the major peptides were determined using a combination of Edman degradation and de novo MS/MS sequencing. We focused on one of these peptides, U1-PONTX-Ae1a (Ae1a), because of its novel sequence, which we predicted would form a novel 3D fold. Ae1a was chemically synthesized using Fmoc chemistry and its 3D structure was elucidated using NMR spectroscopy. The peptide was then tested for insecticidal activity and its effect on a range of human ion channels. Results Seven peptides named poneritoxins (PONTXs) were isolated and sequenced. The three-dimensional structure of synthetic Ae1a revealed a novel, compact scaffold in which a C-terminal β-hairpin is connected to the N-terminal region via two disulfide bonds. Synthetic Ae1a reversibly paralyzed blowflies and inhibited human L-type voltage-gated calcium channels (CaV1). Conclusions Poneritoxins from Anochetus emarginatus venom are a novel class of toxins that are structurally unique among animal venoms. General significance This study demonstrates that Anochetus ant venoms are a rich source of novel ion channel modulating peptides, some of which might be useful leads for the development of biopesticides. © 2016
Address (down) VenomeTech, 473 Route des Dolines, Valbonne, France
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Notes Export Date: 15 September 2016 Approved no
Call Number EcoFoG @ webmaster @ Serial 694
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Author Aili, S.R.; Touchard, A.; Koh, J.M.S.; Dejean, A.; Orivel, J.; Padula, M.P.; Escoubas, P.; Nicholson, G.M.
Title Comparisons of Protein and Peptide Complexity in Poneroid and Formicoid Ant Venoms Type Journal Article
Year 2016 Publication Journal of Proteome Research Abbreviated Journal Journal of Proteome Research
Volume 15 Issue 9 Pages 3039-3054
Keywords ant venom; Hymenoptera; Lc-Maldi-Tof Ms; mass spectrometry; nanoLC-ESI-QTOF MS/MS; peptidome; proteomic analysis; toxin
Abstract Animal venom peptides are currently being developed as novel drugs and bioinsecticides. Because ants use venoms for defense and predation, venomous ants represent an untapped source of potential bioactive toxins. This study compared the protein and peptide components of the poneroid ants Neoponera commutata, Neoponera apicalis, and Odontomachus hastatus and the formicoid ants Ectatomma tuberculatum, Ectatomma brunneum, and Myrmecia gulosa. 1D and 2D PAGE revealed venom proteins in the mass range <10 to >250 kDa. NanoLC-ESI-QTOF MS/MS analysis of tryptic peptides revealed the presence of common venom proteins and also many undescribed proteins. RP-HPLC separation followed by MALDI-TOF MS of the venom peptides also revealed considerable heterogeneity. It was found that the venoms contained between 144 and 1032 peptides with 5-95% of peptides in the ranges 1-4 and 1-8 kDa for poneroid and formicoid ants, respectively. By employing the reducing MALDI matrix 1,5-diaminonapthalene, up to 28 disulfide-bonded peptides were also identified in each of the venoms. In particular, the mass range of peptides from poneroid ants is lower than peptides from other venoms, indicating possible novel structures and pharmacologies. These results indicate that ant venoms represent an enormous, untapped source of novel therapeutic and bioinsecticide leads. © 2016 American Chemical Society.
Address (down) VenomeTech, 473 Route des Dolines, Valbonne, France
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Notes Export Date: 15 September 2016 Approved no
Call Number EcoFoG @ webmaster @ Serial 695
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