Etude de l’activité antifalcémiante d’extraits de racines de Leptadenia hastata Decne. (Asclepiadacae)

L’objectif de cette étude est d’évaluer l’activité antifalcémiante d’extraits de racines de Leptadenia hastata sur des hémoglobines falciformes et d’identifier les principes actifs à l’origine de cette activité. La méthode employée étudie la réversibilité des drépanocytes, en fonction du temps d’incubation des extraits par rapport aux témoins (eau physiologique, phénylalanine et arginine) sur des échantillons de sang de patients drépanocytaires homozygotes. Des concentrations de 0,05; 0,5; 5 et 10 mg/ml de quatre extraits (méthanol, hexane, acétate d’éthyle et méthanol résiduel) ont été mises en contact avec des drépanocytes de type SS après avoir provoqué leur falciformation avec une solution à 2% de métabisulfite de sodium. L’évaluation a été effectuée toutes les 30 minutes pendant 120 minutes. Les différents extraits ont montré une activité dosedépendante sur la réversibilité de la falciformation des globules rouges avec plus de 80% d’inversion en 120 minutes pour l’extrait méthanolique, le plus actif. Un screening phytochimique a permis de faire une corrélation entre les flavonoïdes et l’activité antifalcémiante des extraits de Leptadenia hastata.Mots clés : Drépanocytose, hémoglobine, activité antifalcémiante, Leptadenia hastata, flavonoïdes

Improvement of Fire Hydrant Design to Enhance Water Main Flushing

AbstractFlushing is a good practice to avoid problems related to sediment, bio-film growth, and corrosion. Artificial sediment was removed from fire hydrant with pilot scale water distribution main. The sediment removal in fire hydrant and main was carefully compared with different flow rate with velocity ranged from 0.3 to 3.0 m/s and the depth of fire hydrant from 0.5 m to 1.3m. The drain capability of fire hydrant decreased as the flow rate increased. Sediment with higher density was hard to remove from water main. The length effect of upward fire hydrant was relatively minor. Downward drain showed better efficiency for both sand and actual sediment

Repackaging agricultural research for greater impact on agricultural growth in Africa

Despite the enormous research activities embarked upon by the various research entities in Africa over time, the expected research impacts remain obscure. This paper is a compilation of facts and figures from published peer reviewed articles, agricultural research and development reports from national and international institutions, and base-line data from the Africa Rice Centre aimed at elucidating the performance of agricultural research in Africa between 1960 and 2010. It discusses the constraints to the visible impact of agricultural research on the growth of Africa’s economy, and suggests how to repackage agricultural research for more visible impact on Africa’s economic growth. Results show that agricultural research has been beneficial for African agriculture widely and is believed to be the backbone of the economic growth of the continent. Agricultural research has also served as the bedrock of agricultural technological transformation to enhance agricultural growth. Research has helped to increase agricultural production and productivity and food security in several countries. Also, investment in agricultural research has yielded positive impact on poverty reduction and food security. However, food security and poverty are still visibly mining the African population. The major constraints in the utilization of agricultural research results are the lack of adequate public investment in agriculture, lack of well-trained researchers, inadequate research infrastructures and poor management of the agricultural research and development system. Findings show that in order to package agricultural research for visible impact on the economy, agricultural research systems would need to be adequately funded and handled by skilled human resources under good governance. An effective innovative agricultural policy would demand the initial acknowledgment that a break from the past is necessary to ‘produce more and better’ in Africa and that successful agricultural research systems should be designed in a framework of co-construction, co-execution and co-evaluation

Nianga, laboratoire de l'agriculture irriguée en moyenne vallée du Sénégal

Les actes de l'atelier "Nianga" réunissent des analyses et des points de vue de différents spécialistes qui s'interessent à l'expérience et au devenir de la culture irriguée dans la vallée alluviale de la région du fleuve Sénégal et de son insertion dans les sytèmes de productio

A molecular method to discriminate between mass-reared sterile and wild tsetse flies during eradication programmes that have a sterile insect technique component

Background The Government of Senegal has embarked several years ago on a project that aims to eradicate Glossina palpalis gambiensis from the Niayes area. The removal of the animal try-panosomosis would allow the development more efficient livestock production systems. The project was implemented using an area-wide integrated pest management strategy including a sterile insect technique (SIT) component. The released sterile male flies originated from a colony from Burkina Faso. Methodology/Principal Findings Monitoring the efficacy of the sterile male releases requires the discrimination between wild and sterile male G.p. gambiensis that are sampled in monitoring traps. Before being released, sterile male flies were marked with a fluorescent dye powder. The marking was however not infallible with some sterile flies only slightly marked or some wild flies contaminated with a few dye particles in the monitoring traps. Trapped flies can also be damaged due to predation by ants, making it difficult to discriminate between wild and sterile males using a fluorescence camera and / or a fluorescence microscope. We developed a molecular technique based on the determination of cytochrome oxidase haplotypes of G. p. gambiensis to discriminate between wild and sterile males. DNA was isolated from the head of flies and a portion of the 5' end of the mitochondrial gene cytochrome oxidase I was amplified to be finally sequenced. Our results indicated that all the sterile males from the Burkina Faso colony displayed the same haplotype and systematically differed from wild male flies trapped in Senegal and Burkina Faso. This allowed 100% discrimination between sterile and wild male G. p. gambiensis. Conclusions/Significance This tool might be useful for other tsetse control campaigns with a SIT component in the framework of the Pan-African Tsetse and Trypanosomosis Eradication Campaign (PATTEC) and, more generally, for other vector or insect pest control programs