Embryogenèse somatique chez le cotonnier (Gossypium hirsutum L.) : évolution des composés lipidiques au cours de la callogenèse et de la culture de suspensions cellulaires

L’implication des lipides dans le processus de l’embryogenèse somatique a été étudiée chez deux variétés de cotonnier (Gossypium hirsutum L.) : Coker 312, variété embryogène et ISA 205N, variété non embryogène. Le taux de lipides totaux de la variété ISA 205N est en général plus élevé que celui de la variété Coker 312. Ce taux atteint son optimum à la première subculture des cals et décroît par la suite régulièrement au cours de la culture de cellules. L’analyse qualitative des lipides montre que la composition lipidique des cals est identique chez les deux variétés. Cependant, on observe une accumulation de phospholipides sous forme de phosphocholine triacylglycérol (PTG) dans les suspensions cellulaires embryogènes de la variété Coker 312, contre une accumulation de galactolipides sous forme de digalactosyl diacylglycérol (DGDG) dans les suspensions cellulaires non embryogènes de la variété ISA 205N. Le PTG semble favoriser l’embryogenèse somatique tandis que le DGDG serait une cause de l’inhibition de l’embryogenèse somatique chez le cotonnier.Mots-clés : Gossypium hirsutum L., lipide, cal, suspension cellulaire, embryogenèse somatique

Effets des pratiques phytosanitaires sur l’entomofaune et le rendement du concombre Cucumis sativus (Cucurbitaceae) Linnaeus, 1753 en milieu paysan a Bonoua (Sud-Est de la Côte d’Ivoire)

La forte pression parasitaire en cultures maraichères amène les producteurs à utiliser abusivement les pesticides chimiques. En vue de connaitre leur impact sur l’entomofaune du concombre et le rendement, une étude a été menée d’Août à Novembre 2017 à Bonoua. Cinq parcelles paysannes ont été utilisées. L’une a servi de témoin sans traitement chimique. Deux ont été traitées au DECIS et deux au K-OPTIMAL. Les insectes ont été collectés par des pièges colorés et des filets fauchoirs et leurs dégâts identifiés. Au total, 4133 insectes appartenant à 9 ordres, 27 familles et 42 espèces ont été identifiés. 42,27 % des insectes ont été enregistré à la fructification. La fréquence d’occurrence a révélé que deux espèces prédatrices Solenopsis sp et Camponotus sp ont été omniprésentes. L’espèce défoliatrice Ootheca mutabilis a été la plus abondante au stade préfloraison et le foreur Diaphania hyalinata aux stades floraison et fructification. Les principaux dégâts se traduisent par les perforations de fruits et la chute des fleurs. Les producteurs utilisent onze pesticides chimiques dont le Thiodalm super 40 EC et la Polytrine 10 EC formulés pour culture cotonnière, le Gawa 30 SC pour le cacaoyer. Le meilleur rendement a été obtenu avec le K-OPTIMAL.Mots clés: concombre, insectes ravageurs, insectes utiles, pesticides chimiques, dégâtsEnglish Title: Effects of phytosanitary practices on entomofaune and cucumber yield Cucumis sativus (Cucurbitaceae) Linnaeus, 1753 in Bonoua (south-east of Cote d’Ivoire)English AbstractThe high parasitic pressure in vegetable crops leads producers to abuse chemical pesticides. In order to know their impact on cucumber entomofauna and yield, a study was conducted from August to November 2017 in Bonoua. Five farm plots were used. One served as a control without chemical treatment. Two were treated at DECIS and two at K-OPTIMAL. The insects were collected by colored traps and mowing nets and their damage were identified. A total of 4133 insects belonging to 9 orders, 27 families and 42 species were identified. 42.27 % of the insects were registered to fruiting. The frequency of occurrence revealed that two predatory species Solenopsis sp and Camponotus sp were ubiquitous. The defoliator Ootheca mutabilis was the most abundant species at the pre-flowering stage and the driller Diaphania hyalinata at the flowering and fruiting stages. The main damage is the perforation of fruits, and flowers falling. The producers use eleven (11) chemical pesticides of which Thiodalm super 40 EC and Polytrine 10 EC formulated for cotton culture, Gawa 30 SC for cocoa farming. The best yield was obtained with K-OPTIMAL.Keywords: cucumber, insect pests, useful insects, chemical pesticides, damag

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

Childhood cancer in Côte d’Ivoire, 1995 - 2004 – challenges and hopes

Background. There is insufficient research into the state of paediatric oncology in African countries.Objectives. The purpose of this study was to analyse the state of paediatric oncology between 1995 and 2004 in Côte d’Ivoire.Methods. This retrospective descriptive study analysed all patients under the age of 18 who were diagnosed with cancer in Côte d’Ivoireover a period of 10 years (January 1995 - December 2004) with regard to demographics, types of pathology, delay in diagnosis andtreatment, treatment modalities, abandonment of treatment and survival rate.Results. Of 405 patients diagnosed with cancer, 331 were included in the study. Burkitt’s lymphoma was the most common malignancy (73.6%), followed by nephroblastoma (14.5%) and acute leukaemia (4%). Delay in diagnosis occurred in 38.7% of cases and ranged from 1 to 3 months; the average delay from diagnosis to starting treatment was 18 days. An abdominal mass and swelling of the jaw were the most common clinical presentations. Almost half of the patients (48.6%) were lost to follow-up and over a third (39.3%) died shortly after admission owing to advanced disease. The overall survival rate was 9.4%.Conclusions. Cancer in children in Côte d’Ivoire was dominated by Burkitt’s lymphoma. The rate of loss to follow-up of almost 50% is grounds for concern. The overall survival rate of 9.4% is very low, but such figures are not uncommon for African countries. Collaboration within the Franco-African Group of Paediatric Oncology has contributed to improving the management of children with cancer

Effect of Ethephon Stimulation on Downward Tapping in Latex Production Metabolism on Upward Tapping in PB 217 Clone of Hevea Brasiliensis

In Hevea brasiliensis, Ethephon is used as an exogenous stimulant of latex production. In downward tapping, it has been shown that its misuse has negative consequences on the metabolism of the latex cells of the tree. However, little is known about the impact of this downward tapping practice on latex-producing metabolism in upward tapping. The aim of this study was to determine the effect of stimulation in downward tapping on the latex-producing metabolism in clones PB 217, when the trees are subsequently tapped up. Study was carried out by monitoring the evolution of biochemical parameters of latex and rubber production. From this study, it was found during the last two years of downward tapping that in PB 217 clone, the optimal metabolism of latex production was obtained with 13 Ethephon stimulations per year. When subsequent tapping is done upward, the stimulation frequencies of the trees greater than 4 times per year in downward tapping have a negative impact on the latex-producing metabolism in PB 217 clone of Hevea brasiliensis. However, in cumulative production over the 10 years of downward tapping added to the 2 years of upward tapping, it is the frequency of 13 stimulations per year in downward tapping which is the highest

Climate Variability in the Sudano-Guinean Transition Area and Its Impact on Vegetation: The Case of the Lamto Region in Côte D’Ivoire

Based on unique 50-year datasets from 1962 to 2011, this study diagnoses the variability of climate at Lamto (6.13°N, 5.02°W) in Côte d’Ivoire. A combined pluviothermal index is used to identify climate regions of West Africa. The interdecadal change of the climate is analyzed along with a discussion on the West African Monsoon (WAM) circulation. The impact of vegetation is also analyzed. It is shown that Lamto has mainly a subhumid climate but, in some particular years, this area has a humid climate. Two decades (1962–1971 and 2002–2011) exhibit rainfall excess and the last three ones (1972–1981, 1982–1991, and 1992–2001) show a rainfall deficit that affected West Africa in the early 1970s. The meridional wind field from 1000 hPa to 700 hPa is used to study the WAM variability. The level of the WAM is the lowest (~860–890 hPa) during the active period of the northern wind coming from the Sahara desert (November–February). During 1962–1971 and 2007–2009, the depth of the monsoon at Lamto reaches 300 hPa with an increase in the rainfall. A relationship between potential evapotranspiration and the climate highlights rainfall deficit in 1969 and rainfall excess in 2001–2011

Evaluation in vitro de l’activité des écorces de tige de Anogeissus leiocarpus (DC) Guill. et Perr. (Combretaceae) sur des bactéries responsables de maladies courantes en Afrique et criblage phytochimique

Les bactéries sont à l’origine de réel problème de santé publique à cause de leur implication dans de nombreuses maladies. Leur résistance aux antibiotiques est devenue l’un des problèmes les plus importants dans la lutte contre les maladies infectieuses dans le monde. L’objectif de ce travail est d’évaluer l’activité antibactérienne des extraits hexanique, méthanolique 70% (v/v) et aqueux des écorces de tige de Anogeissus leiocarpus (DC) Guill. et Perr. (Combretaceae), une plante médicinale de la flore ivoirienne, contre les bactéries des genres Staphylococcus, Pseudomonas et les entérobactéries (Shigella sp., Salmonella Typhimurium, Escherichia coli et Proteus mirabilis) par la méthode de diffusion en milieu gélosé dans des cupules et la méthode de macro-dilution en milieu liquide . Les extraits aqueux et méthanolique 70% (v/v) ont été retenus pour la détermination des paramètres antibactériens (CMI et CMB), en raison de leurs activités sur l’ensemble des bactéries sélectionnées. Par ailleurs, une analyse qualitative par chromatographie sur couche mince (CCM), effectuée sur les différents extraits, a permis de détecter plusieurs groupes de composés chimiques parmi lesquels les saponosides, les tanins, les flavonoïdes, les polyphénols, les alcaloïdes et les sesquiterpènes dont des effets antibactériens sont connus. Les CMI obtenues, sont comprises entre 0,7 ± 0,0 et 12,5 ± 0,0 mg/ml. Quant aux CMB, elles varient de 3,1 ± 0,0 à 25,0 ± 0,0 mg/ml. Ce travail justifie l’utilisation traditionnelle de Anogeissus leiocarpus dans le traitement de diverses pathologies et plus particulièrement celles d’origine bactérienne.Mots clés : Antibactérienne, Anogeissus leiocarpus, flore ivoirienne, analyse qualitative

Efficacy of triclabendazole and albendazole against Fasciola spp. infection in cattle in Côte d'Ivoire: a randomised blinded trial

Triclabendazole is the anthelminthic of choice for the treatment of fascioliasis, however, it is not yet registered in many countries. Therefore, we investigated the efficacy of a single-dose of triclabendazole (12 mg/kg) or albendazole (15 mg/kg) against Fasciola spp. infection in cattle on farms in the northern part of Cote d'Ivoire in a randomized clinical trial. Faecal samples were obtained from 196 cattle, of which 155 (79.1%) were found positive for Fasciola spp. by the sedimentation technique. Cattle infected with Fasciola spp. were randomly allocated (3:3:1) to receive triclabendazole (n=66), albendazole (n=67) or left untreated to serve as control (n=22). Follow-up faecal samples were collected on days 21, 28, 90 and 188 post-treatment. No adverse events were observed as reported by the farmer in any of the treatment groups. The proportion of non-egg shedding cattle (PNES), assessed at day 21 (primary outcome), was significantly higher in cattle treated with triclabendazole (95.4%) compared to those receiving albendazole (70.3%; odds ratio [OR] 0.11, 95% confidence interval [CI] 0.03-0.39, p <0.001). The egg reduction rate (ERR) expressed as number of eggs per gram of faeces (epg), a secondary endpoint assessed at day 21 post-treatment, was significantly higher in the triclabendazole arm (arithmetic mean (AM) ERR=99.8%) than in the albendazole arm (AM ERR=92.2%), with a difference of 7.6%-points (95% CI: 0.9-14.5%-points, p=0.03). Reinfection rates at days 90 and 188 post-treatment (secondary endpoint) were lower in the triclabendazole arm (5.3% and 18.5%) compared to the albendazole arm (23.5% and 33.3%). This is the first report of efficacy of triclabendazole against Fasciola spp. in naturally infected cattle in Cote d'Ivoire. Our results confirm that triclabendazole is the most effective treatment of fascioliasis and therefore, should be considered for the control of livestock fascioliasis; if resources allow in combination with intermediate host snail control and raising farmers awareness of pasture and livestock management to avoid reinfection