Caractérisation des isolats de Phytophthora spp du verger cacaoyers de Côte d’Ivoire

Objectifs : La pourriture brune des cabosses due à Phytophthora spp. est l’affection la plus répandue et la plus importante dans la cacaoculture ivoirienne. Cette étude a été réalisée pour caractériser et identifier les isolats de Phytophthora spp à partir des caractères morphologiques et moléculaires.Méthodologie et résultats : Cinquante isolats provenant des principales zones (Est, Centre-Ouest, et Sudouest) du verger cacaoyers de la Côte d’ivoire ont été isolés à partir de cabosses immatures atteintes de pourriture brune. Les caractères phénotypiques asexués et moléculaires à savoir : la longueur, la largeur, le rapport longueur/largeur des sporocystes, la longueur du pédicelle, la forme et la caducité des sporocystes, le type de colonie et l’analyse des fragments de restriction de l’ADN des régions ITS (Espaceur Interne Transcrit) ont été évalués. Les sporocystes des isolats étudiés apparaissaient très variables dans leur forme d’un isolat à un autre. Ils étaient de forme ovoïde, ellipsoïde, obpyriforme, ovoïde-obpyriforme et arrondis à leur base. Les sporanges des isolats observés étaient caducs donc éparpillés avec un pédicelle court (2,92 ± 1,18 Gm). Les sporanges étaient également variables par leur taille, variant entre 33,25 à 55,00 Gm en longueur et entre 21,99 à 34,37 Gm en largeur avec un rapport longueur/largeur variant de 1,23 à 1,94. Les colonies sur culture carotte-agar brut étaient radiées, striés et/ou stellées, et pétaloïdes. L’amplification par ITS-PCR de l’ADN a généré un fragment spécifique de 900 bp. L’analyse des fragments de restriction obtenus après digestion par les endonucléases (AluI ; PvuII ; HaeIII ;HinfI et MspI) a montré que tous les isolats étudiés appartenaient à l’espèce Phytophthora palmivora.Conclusion et application de résultats : Il ressort de notre étude que la technique PCR-RFLP a été plus discriminante par rapport aux méthodes traditionnelles pour caractériser et identifier les isolats de Phytophthora spp. Les résultats montrent également que la technique PCR-RFLP est un moyen rapide sélectif et fiable dans l’identification des Phytophthora spp. En outre, cette méthode peut être utilisée comme outil de prévention et de gestion dans la lutte contre la pourriture brune des cabosses. Cette étude a confirmé la présence de Phytophthora palmivora comme l’espèce la plus prédominante bien que Phytophthora megakarya ait été récemment découverte dans l’Est du verger cacaoyers.Mots clés : pourriture brune ; sporange ; pédicelle ; papille ; Phytophthora spp ; région ITS ; PCR-RFL

Induction et prolifération de cals à partir de l’axe embryonnaire du Voandzou [Vigna subterranea (L.) Verdc. Fabaceae] : effet de la segmentation de l’explant, des phytohormones, de la source de carbone et du génotype

Le Voandzou [Vigna subterranea, (L.) Verdc.], occupe une place importante dans les stratégies élaborées pour assurer la sécurité alimentaire en Afrique subsaharienne. Le développement de systèmes de régénération in vitro de plantes, préalable au transfert de gènes nécessite l’établissement de conditions optimales de la callogenèse. Au cours du présent travail, l’étude des facteurs influençant l’induction et la prolifération des cals chez le Voandzou a été réalisée. L’axe embryonnaire issu de graines matures a été placé sur le milieu de base de Murashige et Skoog (1962) additionné avec les vitamines B5 et supplémenté avec différentes concentrations et combinaisons de phytohormones. Après quatre semaines de culture, les résultats ont montré que l’induction et la prolifération de cals ont été favorisées avec le 2,4-D (0,5 mg/l). La partie basale de l’axe embryonnaire a été la zone la plus favorable à la callogenèse. La meilleure source de carbone a été le saccharose à la concentration optimale de 84 mM. Les meilleurs taux d’induction (100 %) et de prolifération de cals (3) ont été exprimés avec les écotypes Ci2, Ci3, Ci4, Ci5, Ci6, Ci7, Ci10 et Ci21.Mots-clés : voandzou, axe embryonnaire, callogenèse, phytohormones.Callus induction and proliferation from embryonic axis in Bambara groundnut [Vigna subterranea (L.) Verdc. Fabaceae]: effect of explants section, plant growth regulators, carbon source and genotypeBambara groundnut [Vigna subterranea (L.) Verdc. ] contributes to food security in sub-Saharan Africa. Development of efficient systems of in vitro plant regeneration a prerequisite to gene transfer requires establishment of optimal conditions for callus formation. In this work, factors influencing callus induction and proliferation in Bambara have been studied. Embryonic axis derived mature seeds were placed on Murashige and Skoog (1962) medium supplemented with vitamins B5 (MSB5), including different concentrations and combinations of plant growth regulators. After four weeks of culture, results showed that 2,4-D (0.5 mg/L) exhibited the best frequency and proliferation index of callus. Basal part of embryonic axis was the explants of choice for callus induction and proliferation. Sucrose at optimum concentration of 84 mM was favorable to the process of callus formation. Highest callus induction frequency (100 %) and proliferation index (3) were expressed by ecotypes Ci2, Ci3, Ci4, Ci5, Ci6, Ci7, Ci10 and Ci21.Keywords : bambara groundnut, embryonic axis, callogenesis, plant growth regulators

Application d’un modèle conceptuel et d’un modèle de réseaux de neurones artificiels à la simulation des débits annuels dans le bassin versant du N’zi-Bandama (Côte d’Ivoire)

Cette étude présente la comparaison de deux approches de modélisation de la transformation pluie-débit à l'échelle annuelle : un modèle conceptuel et un réseau de neurones artificiels (RNA). Les deux modèles sont appliqués sur trois sous-bassins du fleuve N’zi-Bandama en Côte d'Ivoire. L’analyse comparative est basée sur les performances de simulation en termes de critère de Nash-Sutcliffe. Les modèles ont été testés sur deux périodes, l’une sèche (1973-1997) et l’autre humide (1961-1972). Les données d’entrée des deux modèles sont la pluie et l’évapotranspiration potentielle au pas de temps annuel. Les principaux résultats de ce travail montrent que les performances des deux modèles (conceptuel et neuronal) restent en général satisfaisantes avec des critères de Nash-Sutcliffe supérieurs à 60%. Ces modèles se sont révélés aussi robustes et adaptés pour la simulation des débits annuels des rivières. La comparaison des deux modèles a montré que le réseau de neurones a obtenu des résultats significativement meilleurs que le modèleconceptuel.Mots-clés : modélisation pluie-débit, modèle conceptuel, réseaux de neurones artificiels, N’zi-Bandama, Côte d’Ivoir.Application of a conceptual model and a model of artificial neural networks for the simulation of annual flows in the N'Zi-Bandama watershed (Ivory Coast).This study presents the comparison of two approaches of modelisation of the rainfall-runoff transformation on an annual scale: a conceptual model and an artificial neural network. The two models are applied to three watersheds of the N’zi-Bandama river in Ivory Coast. The comparative analysis is based on the performances of simulation in terms of criterion of Nash-Sutcliffe. The models were tested over two periods, one dries (1973-1997) and the other wet one (1961-1972). The data input of the two models are the rain and the potential evapotranspiration with the step of annual time. The principal results of this work show that the performances of the two models (conceptual and neuronal) remain satisfactory in general with criteria of Nash-Sutcliffe higher than 60%. These models appeared also robust and adapted for the simulation of the annual flow of the rivers. The comparison of the two models showed that the network of neurons had results significantly better than the conceptual model.Keywords : rainfall-runoff modelling, conceptual model, artificial neural network, N’zi-Bandama, Ivory Coast

Management of Hypertension in the Elderly Patient at Abidjan Cardiology Institute (Ivory Coast)

Background. Since the treatment of hypertension is beneficial for the elderly, we have undertaken this study that aims to evaluate the management of hypertension in elderly patient in Côte d'Ivoire. Methods. A retrospective study was conducted among 854 hypertensive elderly patients of Abidjan Cardiology Institute who were followed for a minimum of one year, between January 2000 and December 2009. Results. The patients mean age was 73.1 ± 5.3 years, and 59% were women. At the first presentation, it was mostly systolic-diastolic hypertension (51.8%) and isolated systolic hypertension (38.5%). Mean blood pressure was 169.4 ± 28.4 mmHg for systolic, 95.3 ± 15.7 mmHg for diastolic, and 74.1 ± 22.8 mmHg for pulse pressure. Pulse pressure was ≥60 mmHg in 80.4%. According to the European Guidelines stratification of the cardiovascular risk-excess attributable to high blood pressure, 82.1% of the sample had a very high added risk. The pharmacological therapy was prescribed in 93.5%. More than 66% of patients were receiving ≥2 antihypertensive drugs including fixed-dose combination drugs. The most common agents used were diuretics (63.5%) followed by angiotensin-converting enzyme inhibitors or angiotensin receptor blockers in 61.3%. The most common agents used for monotherapy were calcium antagonists. When ≥2 drugs were used, diuretics and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers were the most common. Blood pressure control was achieved in 42.6%. Conclusion. The control of elderly hypertension can be effective in Sub-Saharan Africa. He required at least two antihypertensive drugs to meet the recommended blood pressure target

Healthy aging: comparative analysis of local perception and diet in two health districts of Côte d'Ivoire and Japan

Context: Good health and longevity depend on dynamic interactions between biological, social, psychological, and environmental factors. Aging is globally a big challenge, particularly with the demographic transition, including population growth, and an emerging burden to society. Knowledge, behavior, diet, and consumption of animal source food were related to aging and emerged as the key factors modulating healthy aging. Objective: The study was designed to understand the main healthy aging factors, such as knowledge, social network, and diet of elders, and to derive mutual learning from it for healthy aging. Methods: A qualitative approach has been applied to explore health-related knowledge, attitude, and diet of elders from Ebetsu (Japan) and Tiassale (Cote d'Ivoire) health districts, using focus group discussions and comparative context analysis between high- and low-income countries. Results: The study shows that living longer is a common feature of people in Japan compared to Cote d'Ivoire, where the life expectancy is still low. Both groups of elders have social networks that support them, and both offer their gained experience to society. While Japanese elders depend on pension and insurance for income and medical treatments, Ivorians depend mostly on their children and social network in old age. The worries of elders differ between the two regions. In Ebetsu, elder members of the community are concerned about the future burden they pose for the younger generation if they develop ill-health, making them more resilient to aging. In Taabo, elders are considered to be culturally and socially useful to the society. Elders in Ebetsu pointed out that for healthy aging, education on diet at a younger age, physical activities, and access to basic social services are the key aspects. This was not observed in Taabo's context. Being inactive and dependent on others were described as the most worrying situations for elders in Ebetsu, as it is perceived to increase the risk of non-communicable diseases and anxiety. Elders in Ebetsu have good knowledge on what constitutes a healthy diet, and they believe that diversifying their diet, reducing portions, and substituting red meat with good animal and vegetable proteins are best eating practices to maintain good health. In Cote d'Ivoire, the diet is imbalanced and the whole family consumes the same meal made mainly with high-energy staples and little protein. However, it is observed in both societies that adopting a good diet is very expensive. Conclusion: The consciousness of aging is universal, but healthy aging varies according to the social systems, education, and knowledge on diet transition. Physical activities, protein-energy balance in diet, and social networks are the key for healthy aging in both contexts. The challenge is to find ways to increase knowledge regarding healthy aging and to strengthen the support system so that healthy aging becomes affordable

Prevalence of Schistosoma mono- and co-infections with multiple common parasites and associated risk factors and morbidity profile among adults in the Taabo health and demographic surveillance system, South-Central Côte d'Ivoire

BACKGROUND: Schistosomiasis remains an important public health problem, also among adults, and infected individuals not treated serve as a reservoir for continued transmission. Despite this fact, evidence on the epidemiology of schistosomiasis in adults in Cote d'Ivoire is scanty. This study aimed to determine the prevalence and risk factors of Schistosoma infection and co-infection with other helminth species and Plasmodium among adults in the Taabo region in the south-central part of Cote d'Ivoire. METHODS: A cross-sectional survey was carried out in April and May 2017 in the frame of the "Cote d'Ivoire Dual Burden of Disease Study" (CoDuBu). A total of 901 randomly selected individuals, aged 18-90 years, provided blood, stool and urine samples for the diagnosis of malaria and helminth infections. Stool samples were subjected to the Kato-Katz technique for detection of Schistosoma mansoni and soil-transmitted helminth eggs, while urine samples were examined for eggs of Schistosoma haematobium and circulating cathodic antigen of S. mansoni. Risk factors and morbidity profiles were assessed using health examination and questionnaires. Multinomial logistic regressions were employed to identify risk factors and morbidity patterns associated with S. mansoni mono- and co-infections. RESULTS: The prevalence of S. mansoni and S. haematobium was 23.2% and 1.0%, respectively. Most S. mansoni were mono-infections (81.3%). Independent determinants of S. mansoni infection were young age, low socioeconomic status (mono- and co-infection) and poor hygiene practices (co-infection) (P < 0.05). S. mansoni infection was independently associated with higher pain and symptom scores (mono-infection), poor self-rated health and low healthcare use (co-infection) (P < 0.05). CONCLUSIONS: This study showed that adults represent a substantial reservoir of S. mansoni. To sustain schistosomiasis control and improve people's wellbeing, it is important to expand preventive chemotherapy from school-aged children to adults, coupled with hygiene and health education

Caracterisation Lithostratigraphique et Sedimentologique des Depôts des Sondages de Fresco et de Grand-Lahou (Sud-Ouest de la Côte d’Ivoire) : Essai de Correlation et Paleoenvironnements

The material studied in this work comes from excavations of five hydraulic soundings in the localities of Fresco and Grand-Lahou located in the Southwest in the "onshore" part of the Ivorian sedimentary basin. These surveys are part of the national program for drinking water supply from aquifers. The lithological and sedimentological analyzes of the cuttings of these holes are carried out in order to identify the different lithological units crossed, to understand the sedimentary processes that have prevailed during the deposition of these sediments and to better characterize the paleoenvironments of deposit. The lithological study revealed mainly clay and sandy in the sedimentation. The granulometry of the sandy levels shows that they are medium to a very coarse sand, fairly well classified, with asymmetry towards the fine elements. Granulometric curves indicate a sigmoidal "S" shape showing a fluvial origin in a relatively medium to strong hydrodynamic deposition environment. The morphoscopy of the quartz grains indicates a dominance of blunted grains that are shiny compared to the rounded and unworn grains, indicating a transport in an aqueous medium far from the source. At Grand-Lahou, the high concentration of carbonate samples implies emplacement in a shallow marine environment and finer sedimentation under calm conditions. The Fresco sediments show a low carbonate content, indicating turbulent and unfavorable medium for limestone precipitation. Le matériel étudié dans ce travail est issu des déblais de cinq sondages hydrauliques implantés dans les localités de Fresco et de Grand-Lahou situées au Sud-Ouest dans la partie « onshore » du bassin sédimentaire ivoirien. Ces sondages s’inscrivent dans le cadre du programme national d’alimentation en eau potable à partir des nappes aquifères. Les analyses lithologiques et sédimentologiques des déblais de ces sondages sont réalisées en vue d’identifier les différentes unités lithologiques traversées, de comprendre les processus sédimentaires ayant prévalus lors du dépôt de ces sédiments et de mieux caractériser les paléoenvironnements de dépôt. L’étude lithologique a mis en évidence une sédimentation essentiellement argileuse et sableuse. La granulométrie des niveaux sableux montre qu’il s’agit des sables moyens à très grossiers, assez bien à mal classés, avec une asymétrie vers les éléments fins. Les courbes granulométriques indiquent une allure en forme sigmoïde « S » traduisant une origine fluviatile dans un environnement de dépôt à hydrodynamisme relativement moyen à fort. La morphoscopie des grains de quartz indique une dominance des grains émoussés luisants par rapport aux rond-mats et non usés, indiquant un transport dans un milieu aqueux loin de la source pourvoyeuse. A Grand-Lahou, la forte concentration des échantillons en carbonates suppose une mise en place dans un milieu marin peu profond et une sédimentation plus fine dans des conditions calmes. Les sédiments de Fresco montrent une teneur en carbonate faible, indiquant un milieu turbulent et défavorable à la précipitation du calcaire

Acceleration of global N₂O emissions seen from two decades of atmospheric inversion

Nitrous oxide (N2O) is the third most important long-lived GHG and an important stratospheric ozone depleting substance. Agricultural practices and the use of N-fertilizers have greatly enhanced emissions of N2O. Here, we present estimates of N2O emissions determined from three global atmospheric inversion frameworks during the period 1998–2016. We find that global N2O emissions increased substantially from 2009 and at a faster rate than estimated by the IPCC emission factor approach. The regions of East Asia and South America made the largest contributions to the global increase. From the inversion-based emissions, we estimate a global emission factor of 2.3 ± 0.6%, which is significantly larger than the IPCC Tier-1 default for combined direct and indirect emissions of 1.375%. The larger emission factor and accelerating emission increase found from the inversions suggest that N2O emission may have a nonlinear response at global and regional scales with high levels of N-input