Intensify pastures for livestock production: vermicompost use, an agro-ecological practice

The intensification of animal production at pasture is essential to meet the growing demand for animal products but also for other functions, the maintenance of areas, livelihoods and well-being of populations. This intensification must also take into account the reduction of agricultural land, promote positive interactions with the environment and biodiversity, while ensuring the supply of populations. The use of vermicompost involving the action of earthworms is an example of agro-ecological practices, to participate in the intensification of grassland and which has been studied in the context of a call to project, AGRIBIO3. Besides the fact that this practice makes it possible to achieve a proper recycling and recovery of various manures, it improves the quality of organic soil, nutrient bioavailability, and grassland biomass while having a nematophagous action, beneficial to a lesser gastrointestinal parasitism of grazing small ruminants. The biological and financial advantages of this practice in the longer term, and their use to various grassland systems must be quantified

The role of WNK in modulation of KCl cotransport activity in red cells from normal individuals and patients with sickle cell anaemia

Abstract: Abnormal activity of red cell KCl cotransport (KCC) is involved in pathogenesis of sickle cell anaemia (SCA). KCC-mediated solute loss causes shrinkage, concentrates HbS, and promotes HbS polymerisation. Red cell KCC also responds to various stimuli including pH, volume, urea, and oxygen tension, and regulation involves protein phosphorylation. The main aim of this study was to investigate the role of the WNK/SPAK/OSR1 pathway in sickle cells. The pan WNK inhibitor WNK463 stimulated KCC with an EC50 of 10.9 ± 1.1 nM and 7.9 ± 1.2 nM in sickle and normal red cells, respectively. SPAK/OSR1 inhibitors had little effect. The action of WNK463 was not additive with other kinase inhibitors (staurosporine and N-ethylmaleimide). Its effects were largely abrogated by pre-treatment with the phosphatase inhibitor calyculin A. WNK463 also reduced the effects of physiological KCC stimuli (pH, volume, urea) and abolished any response of KCC to changes in oxygen tension. Finally, although protein kinases have been implicated in regulation of phosphatidylserine exposure, WNK463 had no effect. Findings indicate a predominant role for WNKs in control of KCC in sickle cells but an apparent absence of downstream involvement of SPAK/OSR1. A more complete understanding of the mechanisms will inform pathogenesis whilst manipulation of WNK activity represents a potential therapeutic approach

Rapid effects of plant species diversity and identity on soil microbial communities in experimental grassland ecosystems

Changes in plant community structure, including the loss of plant diversity may affect soil microbial communities. To test this hypothesis, plant diversity and composition were experimentally varied in grassland plots cultivated with monocultures or mixtures of 2, 3 or 4 species. We tested the effects of monocultures versus mixtures and of plant species composition on culturable soil bacterial activity, number of substrates used and catabolic diversity, microbial biomass N, microbial respiration, and root biomass. These properties were all measured 10 months after seeding the experiment. Soil bacterial activity, number of substrates used and catabolic diversity were measured in the different plant communities using BIOLOG GN and GP microplates, which are redox-based tests measuring capacity of soil culturable bacteria to use a variety of organic substrates. Microbial biomass N, microbial respiration, and root biomass were insensitive to plant diversity. Culturable soil microbial activity, substrates used and diversity declined with declining plant diversity. Their activity, number of substrates used and diversity were significantly higher in plots with 3 and 4 plant species than in monocultures and in plots with 2 species. There was also an effect of plant species composition. Culturable soil microbial activity and diversity was higher in the four-species plant community than in any of the plant monocultures suggesting that the effect of plant diversity could not be explained by the presence of a particular plant species. Our results showed that changes in plant diversity and composition in grassland ecosystems lead to a rapid response of bacterial activity and diversity. (c) 2006 Elsevier Ltd. All rights reserved

Study of antidiabetic properties and chemical composition of two Phyllanthus species usually consumed by Guadeloupean: Phyllanthus amarus Schum. & Thonn. (1827) and Phyllanthus debilis Klein ex Wild. (1806)

International audienceMany people worldwide use plants, alone or in combination with their antihyperglycemic drugs, to manage their type 2 diabetes mellitus [1][2]. Most researches on therapeutic properties of herbs are carrying out on methanolic or ethanolic extracts [3]. However, these studies are not representative of the population consumption habits. For the first time, a study was performed with specimens of the two mostly used species in Guadeloupe: Phyllanthus amarus and Phyllanthus debilis. The chemical composition of aqueous infusion of dried aerial parts were evaluated in relationship to antidiabetic mechanisms occurring at the level of glucose homeostasis in cultured hepatocytes (H4IIE) and muscle cells (C2C12). On the one hand, the extracts of P. amarus showed a significant activity in glucose uptake on muscle cells with an increase of 23.11 ± 3.84 % whereas it was no significant for P. debilis (13.4 ± 3.28 %). On the other hand, the same extracts of P. debilis showed stronger inhibition of hepatocellular G6Pase activity (65.88 ± 4.28 %), close to the action of insulin (64.29 ± 4.59 %), than P. amarus extracts (34.6 ± 1.45 %). The comparison of their chemical composition demonstrated the presence of polyphenols, especially hydrolyzable ellagitannins, involved in their antidiabetic effects. Only four molecules were common to both species, galactaric acid lactone, gallic acid, 5-O-(E)-caffeoyl galactaric acid, a new compound found for the first time in both species, and geraniin. The study of the antidiabetic activity of geraniin, which is predominant in P. debilis, showed a significant inhibition of G6Pase (60.67 ± 2.33 %) whereas no significant activity was observed for glucose uptake. These results suggest that this compound greatly influence the antidiabetic effects of the Phyllanthus crude extracts.[1] Genthon, L. (2014). Contribution à l’étude de la connaissance et de l’utilisation des plantes de la pharmacopée locale par la population guadeloupéenne. [2] Patel, J. R., Tripathi, P., Sharma, V., Chauhan, N. S., & Dixit, V. K. (2011b). Phyllanthus amarus: Ethnomedicinal uses, phytochemistry and pharmacology: A review. Journal of Ethnopharmacology, 138(2), 286-313. doi:http://dx.doi.org/10.1016/j.jep.2011.09.040[3] Kumaran, A., & Joel Karunakaran, R. (2007). In vitro antioxidant activities of methanol extracts of five Phyllanthus species from India. LWT - Food Science and Technology, 40(2), 344-352. doi:http://dx.doi.org/10.1016/j.lwt.2005.09.01

A viability model of farming systems, the case of French West Indies

Compléter avec les actesCompléter affilitationOne the aims of the multidisciplinary research project Gaia-Trop on viability and adaptive management of small tropical islands agro-systems, was to devise a new model of farm system using tools of the mathematical viability theory. It has been constructed in close cooperation with French West Indies farmers to take into account their needs and expectations. The main emerging points focused on soil degradation, pest disease and climatic risks and economic constraints. A specific software is being developed for the viability calculus that will be made available for this community. We present first insights of this model and results obtained for only one parcel and without taking uncertainties at this stage. lt highlights that the objective of restoring the soil quality in the long term can be unstainable for farmers facing with financial constraints. The issue of sharing the costs of the agro-ecological transition must be asked