Cabanillas, B. J., Le Lamer, A. C., Castillo, D., Arevalo, J., Rojas, R., Odonne, G., et al. (2010). Caffeic Acid Esters and Lignans from Piper sanguineispicum. J. Nat. Prod., 73(11), 1884–1890.
Abstract: Three new caffeic acid esters (1-3), four new lignans (4-7), and the known compounds (7'S)-parabenzlactone (8), dihydrocubebin (9), and justiflorinol (10) have been isolated from leaves of Piper sanguineispicum. Their structures were determined by spectroscopic methods, including 1D and 2D NMR, HRCIMS, CD experiments, and chemical methods. Compounds 1-10 were assessed for their antileishmanial potential against axenic amastigote forms of Leishmania amazonensis. Caffeic acid esters 1 and 3 exhibited the best antileishmanial activity (IC50 2.0 and 1.8 μM, respectively) with moderate cytotoxicity on murine macrophages.
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Scotti, I., González-Martínez, S. C., Budde, K. B., & Lalague, H. (2016). Fifty years of genetic studies: what to make of the large amounts of variation found within populations? Annals of Forest Science, 73(1), 69–75.
Keywords: Intra-specific variation; Microgeography; Natural selection; Population genomics
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Thibaut, B., Denaud, L., Collet, R., Marchal, R., Beauchene, J., Mothe, F., et al. (2016). Wood machining with a focus on French research in the last 50 years. Annals of Forest Science, 73(1), 163–184.
Abstract: Key message: Wood machining is compulsory both for timber separation and the surfacing of wooden objects. The anisotropy, cellular nature and multi-scale level organisation of wood make its cutting complicated to study. During the last 50 years, most of the wood machining subjects were covered by French teams. Context: Woodcutting is a very old technology but scientific research is scarce on the subject. In the last 50 years, much work on basic mechanisms as well as on industrial processes has been done in France. Aims: The specific nature of wood introduces strong differences between wood and metal cutting processes. The paper focuses on French teams’ contributions. Results: The basic aspects of the tool–material interaction for different basic modes in woodcutting are highlighted. In primary conversion such as sawing, veneer cutting or green wood chipping, huge progress comes from automation and the possibility of linking the process to log and product quality through new sensors. In secondary processing, much has been done on the links between the cutting process, surface qualification and the properties of these surfaces for further processing, such as gluing or coating. Tool wear depends on the cutting process, timber quality and species. Trade-offs are required in tool technology and coating technologies may improve tool life. Conclusion: A large amount of knowledge and innovation has come from 50 years of worldwide research effort, with France being particularly active in this period. The transfer of skills from metals cutting industry was often a key, but much is needed to move closer to both metal cutting sector and woodcutting skills among craftsmen. © 2015, INRA and Springer-Verlag France.
Keywords: Primary conversion; Secondary processing; Surface quality; Tool wear
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Bonal, D., Burban, B., Stahl, C., Wagner, F., & Herault, B. (2016). The response of tropical rainforests to drought—lessons from recent research and future prospects. Annals of Forest Science, 73(1), 27–44.
Abstract: Key message: We review the recent findings on the influence of drought on tree mortality, growth or ecosystem functioning in tropical rainforests. Drought plays a major role in shaping tropical rainforests and the response mechanisms are highly diverse and complex. The numerous gaps identified here require the international scientific community to combine efforts in order to conduct comprehensive studies in tropical rainforests on the three continents. These results are essential to simulate the future of these ecosystems under diverse climate scenarios and to predict the future of the global earth carbon balance. Context: Tropical rainforest ecosystems are characterized by high annual rainfall. Nevertheless, rainfall regularly fluctuates during the year and seasonal soil droughts do occur. Over the past decades, a number of extreme droughts have hit tropical rainforests, not only in Amazonia but also in Asia and Africa. The influence of drought events on tree mortality and growth or on ecosystem functioning (carbon and water fluxes) in tropical rainforest ecosystems has been studied intensively, but the response mechanisms are complex. Aims: Herein, we review the recent findings related to the response of tropical forest ecosystems to seasonal and extreme droughts and the current knowledge about the future of these ecosystems. Results: This review emphasizes the progress made over recent years and the importance of the studies conducted under extreme drought conditions or in through-fall exclusion experiments in understanding the response of these ecosystems. It also points to the great diversity and complexity of the response of tropical rainforest ecosystems to drought. Conclusion: The numerous gaps identified here require the international scientific community to combine efforts in order to conduct comprehensive studies in tropical forest regions. These results are essential to simulate the future of these ecosystems under diverse climate scenarios and to predict the future of the global earth carbon balance. © 2015, INRA and Springer-Verlag France.
Keywords: Carbon; Climate; Drought; Global change; Growth; Mortality; Soil; Tropical; Water
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Schimann, H., Bach, C., Lengelle, J., Louisanna, E., Barantal, S., Murat, C., et al. (2017). Diversity and Structure of Fungal Communities in Neotropical Rainforest Soils: The Effect of Host Recurrence. Microbial Ecology, 73(2), 310–320.
Abstract: The patterns of the distribution of fungal species and their potential interactions with trees remain understudied in Neotropical rainforests, which harbor more than 16,000 tree species, mostly dominated by endomycorrhizal trees. Our hypothesis was that tree species shape the non-mycorrhizal fungal assemblages in soil and litter and that the diversity of fungal communities in these two compartments is partly dependent on the coverage of trees in the Neotropical rainforest. In French Guiana, a long-term plantation and a natural forest were selected to test this hypothesis. Fungal ITS1 regions were sequenced from soil and litter samples from within the vicinity of tree species. A broad range of fungal taxa was found, with 42 orders and 14 classes. Significant spatial heterogeneity in the fungal communities was found without strong variation in the species richness and evenness among the tree plots. However, tree species shaped the fungal assemblages in the soil and litter, explaining up to 18 % of the variation among the communities in the natural forest. These results demonstrate that vegetation cover has an important effect on the structure of fungal assemblages inhabiting the soil and litter in Amazonian forests, illustrating the relative impact of deterministic processes on fungal community structures in these highly diverse ecosystems. © 2016, Springer Science+Business Media New York.
Keywords: Amazonian forest; Fungal communities; Host recurrence; Litter; Second-generation sequencing; Soil
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Basset, C., Rodrigues, A. M. S., Eparvier, V., Silva, M. R. R., Lopes, N. P., Sabatier, D., et al. (2012). Secondary metabolites from Spirotropis longifolia (DC) Baill and their antifungal activity against human pathogenic fungi. Phytochemistry, 74, 166–172.
Abstract: A phytochemical study of the ethyl acetate extract of the roots and adventitious roots of Spirotropis longifolia, a monodominant tree species of the Guianan rainforest, has allowed the isolation of three compounds: 2-hydroxy-8,9-methylenedioxy-2′,2′-dimethylpyrano-[5′, 6′:4,3]-6a-prenyl-[6aS,11aS]-pterocarpan (spirotropin A), 2-hydroxy-8,9-methylenedioxy-2′,2′-dimethyl-3′, 4′-dihydropyrano-[5′,6′:4,3]-6a-prenyl-[6aS,11aS]-pterocarpan (spirotropin B), and 5,7-dihydroxy-6,8-diprenyl-2,2-dimethylpyrano[5,6: 3′,4′]-isoflavone (spirotropone). In addition, 10 known compounds, trans-oxyresveratrol, trans-resveratrol, piceatannol, daidzein, genistein, isoprunetin, lupeol, latifolol, gnetin D and gnetin E, were also isolated. These compounds were evaluated for their antifungal activity and their cytotoxicity, and their structures were established by 1D and 2D NMR, HRMS, CD and optical rotation measurements. © 2011 Elsevier Ltd. All rights reserved.
Keywords: Antifungal; Cytotoxic; Leguminosae; Monodominant species; Prenylated pterocarpans; Spirotropis longifolia
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Niamké, F. B., Amusant, N., Stien, D., Chaix, G., Lozano, Y., Kadio, A. A., et al. (2012). 4',5'-Dihydroxy-epiisocatalponol, a new naphthoquinone from Tectona grandis L. f. heartwood, and fungicidal activity. Int. Biodeterior. Biodegrad., 74, 93–98.
Abstract: A new naphthoquinone derivative was isolated from the heartwood of the teak stem. The chemical structure of this new compound, 4',5'-dihydroxy-epiisocatalponol, was determined using 1-D and 2-D nuclear magnetic resonance experiments, vibrational circular dichroism, HRMS, and optical rotation. We showed that this new naphthoquinone derivative plays a key role in the variability of decay resistance in teak wood. A high negative correlation was found between its concentration and the mass losses of the wood samples after exposure to the brown rot Antrodia sp., the fungus that is the most virulent against teak (R = -0.9; ρ < 0.0001). In-vitro bioassays allowed us to demonstrate that 4',5'-dihydroxy-epiisocatalponol acted as a fungicide against Trametes versicolor (white rot) at 58 mg ml -1 (0.22 mM). Overall, our results demonstrated that the concentration of 4',5'-dihydroxy-epiisocatalponol could be used as a new tool to evaluate teak wood durability. © 2012 Elsevier Ltd.
Keywords: 4',5'-Dihydroxy-epiisocatalponol; Decay resistance; Fungicidal; Heartwood; Naphthoquinone; Tectona grandis
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Rodrigues, A. M. S., Stien, D., Eparvier, V., Espindola, L. S., Beauchene, J., Amusant, N., et al. (2012). The wood preservative potential of long-lasting Amazonian wood extracts. International Biodeterioration and Biodegradation, 75, 146–149.
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.
Keywords: Durable wood extracts; Handroanthus serratifolius; Rotting fungi; Wood preservation
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Anouhe, J. - B. S., Niamké, F. B., Faustin, M., Virieux, D., Pirat, J. - L., Adima, A. A., et al. (2018). The role of extractives in the natural durability of the heartwood of Dicorynia guianensis Amsh: new insights in antioxydant and antifungal properties. Annals of Forest Science, 75(1).
Abstract: Key message: The natural durability of Dicorynia guianensis Amsh’s Heartwood is conferred by the high content of antioxidant phenolic compounds, especially tannins and flavonoids combined with the presence of fungistatic alkaloids. The content of phenolic compounds increases according to the natural durability classes, from durable wood (class 2) to moderately durable wood (class 3) and correlated to the antioxidant capacity.
Context: The heartwood of Dicorynia guianensis Amsh is resistant to white rot fungi decay, but the mechanism of this natural durability is not fully elucidated.
Aims: Biochemical studies were carried out in order to better understand the role of extractives in natural durability of D. guianensis.
Methods: The powders from durable and moderately durable heartwood were extracted with methanol, ethanol, and hot water. The quantity of total phenols, tannins, and flavonoids as well as antioxidant activity, evaluated by 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) were determined using colorimetric methods. Antifungal activity was assessed by using two white rot fungi. The bioactive fractions and compounds were obtained using bio-guided fractionation, HPLC isolation, MS and RMN spectroscopic analyses.
Results: Durable woods contain higher amounts of heartwood extract and antioxidant activity. Antioxidant activity was highly correlated with the content of phenolics. The purification of the most antioxidant fraction FII affords the characterization of (+)-catechin (−)-epicatechin, neoastilbin, astilbin, and isoastilbin. Alkaloid fraction FIII exhibits dose-dependent fungistatic activity against Pycnoporus sanguineus Linnaeus and Trametes versicolor Quelet.
Conclusion: Phenolic antioxidants and fungistatic alkaloids positively impact the natural durability of D. guianensis.
Keywords: Alkaloid; Antifungal; Antioxidant; Dicorynia guianensis; Heartwood; Natural durability; Phenols
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Barr, C. B., Cerdan, A., Clavier, S., & Murienne, J. (2021). Amazonopsis cerdani (Coleoptera: Elmidae: Elminae), a New Species of RiffleBeetle from French Guiana with Habitat Observations. The Coleopterists Bulletin, 75(2), 427–439.
Abstract: A third species of Amazonopsis , Amazonopsis cerdani Barr and Cerdan, new species (Coleoptera: Elmidae), is herein described from French Guiana. One female paratype of Amazonopsis theranyi Barr from Peru is tentatively reassigned to A. cerdani as a non-paratype. Photographic images of the male and female habitus, and the male genitalia, are provided, as is a distribution map and a key to the species. Amazonopsis cerdani differs from A. theranyi from Peru and Amazonopsis camachoi Barr from Venezuela by the presence of prominent spines on protarsomeres 1–4 of males, among other characters. The habitat of this species is small, shallow, lowland streams with sandy-silty substrates and low flow. Specimens were collected from unconsolidated leaf litter in depositional areas, and from stick and leaf packs lodged in the current. Genetic analysis conducted on three specimens from two localities, a male and two females, showed that they are conspecific.
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