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Antifungal and anti-termite activities relating to chemical composition of pyrolysis liquid from carbonization of five Tunisian wood species
No full textPurpose: The pyrolysis of the 5 most promising Tunisian wood species (Ceratonia siliqua, Eucalyptus camaldulensis, Eucalyptus maidenii, Pinus pinea, and Quercus canariensis) for charcoal production was carried out in a custom-designed carbonization reactor developed at the INRGREF's Wood Technology Section (Tunis, Tunisia). This process aimed to produce both char and pyrolysis by-products, particularly tars. This research is focused on the better understanding of the chemical composition of tars and their mechanisms of anti-fungal and anti-termite activities. Methods: The experiments were conducted at temperatures ranging from 450 to 550 °C, depending on the wood species, with a controlled heating rate of 1.5 °C/min and a holding time of 12 h. The global yield of char and pyrolysis by-products (tars, liquid and gas) were determined for all wood species, separately. Then, the chemical compositions of tars, obtained by pyrolysis liquids decantation process, were analyzed by Gas-Chromatography coupled with Mass Spectrometry (GC–MS) analysis and their antifungal and anti-termite properties were evaluated. Results: The average yield of char and tar was 27.00% and 40.00%, respectively. The level of antifungal and anti-termite properties of the Tunisian wood tars depends on the nature of the initial biomass, which plays a crucial role in the chemical composition of the obtained tars. The effectiveness, in term of biological activity, of the pyrolysis tar is believed to result from the synergetic action of its various chemicals, notably organic acids, phenolics, terpenes, aldehydes and ketones and PAHs compounds. Notably, the chemical profile of the pyrolysis tars was closely linked to their effectiveness in inhibiting fungal growth and repelling termites. Among the tested samples, the tar derived from Pinus pinea exhibited the strongest bioactivity against white and brown fungal strains as well against subterranean termites. Conclusion: These findings suggest that pyrolysis tars obtained from the carbonization of Tunisian wood species could serve as promising natural preservatives for protecting wood against fungal decay and termite attacks. However, further work on formulations should be carried out to ensure extended efficacy over time while minimizing impacts on human health and the environment. Moreover, since all tar solutions contain non-negligible PAHs content, it will be essential to assess the eco-toxicity of these solutions
Mapping out the yields of energy crops with data-driven global models, including climate and soil predictors
Get PDFLignocellulosic crops such as Miscanthus, Eucalyptus, Poplar, Willow, and Switchgrass are gaining attention as promising feedstocks for renewable energy and carbon-mitigation strategies, especially on marginal lands. Assessing their global yield potentials requires models that go beyond climate drivers alone. Using a global dataset of 3963 yield observations for five species, we developed a high-resolution (5-arc-minute) modeling framework that augments climate with detailed soil and topographic predictors. Among seven machine learning algorithms, Random Forest, Extra Trees, and Gradient Boosting (GB) emerged as top performers. On an independent test set, the best model achieved a root mean square error (RMSE) of 4.8 t DM ha−1 year−1 (across algorithms: 4.7–5.0 t DM ha−1 year−1) and an of 0.67, a moderate error relative to the broad 4–19 t DM ha−1 year−1 spatial yield range. After outlier handling via a two-phase cross-validation procedure, each model was applied globally under current climate and three future scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5). Across scenarios (relative to the 1980–2000 baseline), median absolute yield changes over suitable land are modest (ca. 1–2 t DM ha−1 year−1), yet localized hotspots show gains or losses up to 8 t DM ha−1 year−1. Yields most often increase in presently cool, high-latitude areas and decrease in warmer/drier or edaphically constrained low-latitude regions. We additionally provide a “best-crop” map identifying where each species may offer the most favorable balance between yield and production cost, revealing pronounced geographic variation in suitability. Compared with alternative models based on coarser-resolution datasets, our approach generally yields more conservative estimates, likely reflecting the added constraint from soil and topographic predictors. These results underscore the importance of representing local environmental heterogeneity when predicting energy-crop productivity under climate change
dCas9-SPO11-1 locally stimulates meiotic recombination in rice
Get PDFIntroduction: Meiotic crossovers shuffle the genetic information transmitted by the gametes. However, the potential to recover all the combinations of the parental alleles remains limited in most organisms, including plants, by the occurrence of only few crossovers per chromosome and a prominent bias in their spatial distribution. Thus, novel methods for stimulating recombination frequencies and/or modifying their location are highly desired to accelerate plant breeding. Methods: Here, we investigate the use of a dCas9-SPO11-1 fusion and clusters of 11 gRNAs to alter meiotic recombination in two chromosomal regions of a rice hybrid (KalingaIII/Kitaake). To accurately genotype rare recombinants in regions of few kbp, we improved the digital PCR-based pollen-typing method in parallel. Results: Expression of the dCas9-SPO11-1 fusion protein under the ubiquitous ZmUbi1 promoter was obtained in leaves/anthers/meiocytes and found to complement the sterility of the Osspo11-1 mutant line. We observed a 3.27-fold increase over wild-type (p<0.001) of recombinant pollens in a transgenic hybrid line (7a) targeting a chromosome 7 region. In the offspring plant 7a1, a significant 2.05-fold increase (p=0.048) was observed in the central interval (7.2 kb) of the Chr. 7 target region. This stimulation of meiotic recombination is consistent with the expression of the dCas9-SPO11-1 fusion and gRNAs as well as with the ChIP-revealed binding of dCas9-SPO11-1 to the targeted region. In contrast, no stimulation was observed in other transgenic lines deficient in the above pre-requisite features, expressing the dCas9-SPO11-1 fusion but no gRNAs or targeting a Chr.9 region. Discussion: These results open new avenues to locally stimulate meiotic recombination in crop genomes and paves the way for a future implementation in plant breeding programs
Torreya grandis nut peptides regulate lipid-II inhibitors in high-fat diet-fed mice
Get PDFPlant-derived bioactive peptides have drawn increasing attention in the field of nutrition and food science due to their biological activities, low cost, safety, and ease of industrial production. Functional peptides from Torreya grandis are being investigated due to their potential as dietary supplements. This study focuses on T. grandis nut peptides that regulate LIPID-II inhibitor in mice fed a high-fat diet. Proteome analysis identified a Vicilin-like antimicrobial peptide involved in host defense. 16S rRNA Sequencing revealed alteration in gut microbiota with T. grandis administration as manifested by increased Akkermansia and Parabacteroides concurrently by decreased Firmicutes. Beneficial bacteria i.e., Akkermansia improved intestinal functions and increased levels of short chain fatty acids (SCFAs). T. grandis supplementation in HFD mice reduced body weight, TC, TG, LDL, and decreased inflammation, while reducing oxidative stress and increasing HDL in the model group fed a high-fat diet. Lipid droplets in liver, muscles, and blood vessels were highly reduced, evoked by the high peptide group. Transcriptome analysis highlighted lipid regulation via the PPAR-α pathway, with molecular docking revealing 4 potential lipid II inhibitory peptides. These findings suggested T. grandis as a promising supplement in food and a key nut for nutraceutical purposes
Sterile insect technique in a patch system: Influence of migration rates on optimal single-patch releases strategies
No full textThe Sterile Insect Technique (SIT) is a biological control method used to reduce or eliminate pest populations or disease vectors. This technique involves releasing sterilized insects that, upon mating with the wild population, produce no offspring, leading to a decline or eventual eradication of the target species. We incorporate a spatial dimension by modeling the pest/vector population as being distributed across multiple patches, with both wild and released sterile insects migrating between these patches at predetermined rates. We mainly focus on a two-patch system. This study has two primary objectives: first, to derive sufficient conditions for achieving the elimination of the wild population through SIT, whether releases occur in one patch or in both patches. In particular, we provide an estimate of the minimal release rates to reach elimination thanks to the diffusion rates between patches. This is the first time that such a result is given in a general manner. Second, we study an optimal SIT control strategy, where we minimize the total amount of sterile insects to release, and show that, within one patch, it can successfully reduce the wild population in that patch to a desired level within a finite time frame, provided that the migration rates between patches are sufficiently low. Numerical simulations are employed to illustrate these results and further analyze the outcomes
From local actors to leaf carers: Companion modeling for rethinking tree protection in Senegal's Groundnut Basin
Get PDFHow can a participatory simulation model contribute to understanding social-ecological dynamics and fostering alternative strategies for the sustainable management of trees, considering their role in enhancing soil fertility and contributing to farmers' food security? In Senegal's groundnut-growing region (Peanut Basin) , the Sahelian ecosystems have undergone significant degradation, characterized by a reduction in tree cover, as a consequence of the droughts in the 1960s and the 1990s. The Peanut Basin stands out for its positive interrelationships between trees, crops, and pastoralism. However, the regeneration of the Faidherbia albida tree population, essential to these interrelationships, has declined since the major droughts. Through collaborative efforts with agro-pastoral farmers living in the area, we developed a simulation model –- The SAFIRe model : Simulation of Agents for Fertility, Integrated Energy, Food security, and Reforestation –- that aims to identify, in collaboration with local communities, ways to reduce the pressure on tree populations and to restore conditions for medium-term tree regeneration. By exploring the results of the model co-designed with local stakeholders, we identified potentially more effective management strategies. More importantly, we have collectively questioned the conditions for improving tree cover and the viability of the socio-ecosystem, particularly in relation to the demand for firewood and local cereal for sustenance. This has prompted the stakeholders to engage in community-wide discussions and transform agro-pastoralists into leaf carers
Lutte contre la déforestation en Amazonie : pourquoi la légalité est importante ?
Get PDFDéclaration de New York sur les forêts, Moratoire du soja au Brésil, Règlement européen de lutte contre la déforestation et la dégradation des forêts, Accords zéro déforestation en Colombie, etc. : la persistance de la déforestation dans les régions tropicales conduit à de multiples engagements, tant dans les pays du Nord que dans les pays du Sud. La mise en oeuvre de ces engagements fait face à de nombreux obstacles et la différence entre déforestation légale, c'est-à-dire autorisée par le cadre réglementaire de chaque pays, et illégale, est souvent occultée dans les systèmes de suivi de la déforestation, nationaux ou internationaux. Ces deux constats sont en réalité liés. Il est indispensable de différencier déforestation légale et illégale pour que les engagements se traduisent de fait par une réduction soutenue de tout type de déforestation en région tropicale. En Amazonie, cette différenciation requiert la coordination d'informations d'institutions à différentes échelles
Why legality is important in fighting deforestation in the Amazon
Get PDFOngoing deforestation in tropical regions has given rise to numerous commitments in countries of both the Global North and Global South: The New York Declaration on Forests, the Brazilian Soy Moratorium, the European Union Deforestation Regulation, zero-deforestation agreements in Colombia, etc. Implementing those commitments faces many obstacles and the difference between illegal deforestation and legal deforestation, i.e. that authorized by the regulatory framework of each country, is often glossed over in national or international deforestation monitoring systems. These two observations are in fact linked. It is essential to distinguish between legal and illegal deforestation so that commitments effectively result in a sustained reduction of all types of deforestation in tropical regions. In the Amazon, that distinction requires the coordination of information from institutions on different levels
Combate ao desmatamento na Amazônia: por que a legalidade é importante?
Get PDFDeclaração de Nova York sobre Florestas, Moratória da Soja no Brasil, Regulamento Europeu de Combate ao Desmatamento e à Degradação Florestal (EUDR), Acordos de Desmatamento Zero na Colômbia, etc.: a persistência do desmatamento nas regiões tropicais motivou múltiplos compromissos, tanto por parte dos países do Norte quanto dos países do Sul. A implementação desses compromissos enfrenta inúmeros obstáculos. A diferença entre desmatamento legal, ou seja, autorizado pelo quadro normativo de cada país, e desmatamento ilegal, é frequentemente ocultada nos sistemas nacionais ou internacionais de monitoramento do desmatamento. Essas duas observações estão, de fato, interligadas. É indispensável diferenciar desmatamento legal e ilegal para que os compromissos se traduzam em uma redução sustentada de todos os tipos de desmatamento nas regiões tropicais. Na Amazônia, essa diferenciação exige a coordenação de informações de instituições em diferentes escalas