Bathymétrie d’une baie lagunaire et son incidence sur la répartition des métaux lourds : cas de la baie d’Abouabou en lagune Ebrié, Côte d’Ivoire

La lagune Ebrié et ses baies sont le siège d’une sédimentation active notamment par les métaux lourds (zinc, fer, cuivre, manganèse, mercure et cadmium). La baie d’Abouabou, qui appartient à cette lagune, n’échappe pas à ce phénomène. Plusieurs facteurs peuvent influencer la répartition de ces métaux dans les fonds lagunaires. A partir de la bathymétrie de la baie, il a été mis en évidence l’influence de celle-ci sur la répartition de ces métaux. La nouvelle carte bathymétrique réalisée a révélé un taux de comblement de la baie de l’ordre de 14 cm/an entre 1979 et 2000.Mots-clés: lagune Ebrié, baie d’Abouabou, métaux lourds, bathymétrie, Côte d’Ivoire Bathymetry of a bay and its impact on the variation of heavy metals: cas of Abouabou bay in Ebrié Lagoon, Côte d’Ivoire The Ebrié lagoon and its bays are the area of an active sedimentation especially by the heavy metals polluting (zinc, iron, copper, manganese, mercury and cadmium). It is the case of the bay of Abouabou of the Ebrié lagoon. Several factors can influence the variation of these metals in the lagoon. From the bathymetry, it was highlighted the influence of this one on the distribution of these metals. Moreover bathymetry revealed that this bay undergoes a filling which is estimated at 3 m between 1979 and 2000.Keywords: EbriéLagoon, Abouabou bay, heavy Metals, Bathymetry, Côte d’Ivoir

Prevalence of Bacillus cereus and emetic strains detection from Ivory Coast local flours

Bacillus cereus is a pathogen associated with diarrheal and emetic food borne illness. However, in Africa, the prevalence of food borne infections attributable to this bacterium is difficult to establish accurately. Given the involvement of farinaceous foods in the majority of emetic outbreak and the dietary habits in Ivory Coast, implying an increase in the consumption of traditionally produced flours, the prevalence of Bacillus cereus and emetic strains associated to local flours produced in Abidjan were assessed. In this purpose, 100 samples of millet, maize and cassava flours were collected from five different Abidjan municipalities. Microbiological analysis were carried out in accordance with the standard EN ISO 7932 : 2004 and the European regulation EC 2073/2005, to enumerate the Bacillus cereus.. Bacillus cereus strains isolated were screened by polymerase chain reaction, for emetic strains detection. Overall, 31 (31 %) of maize, millet and cassava flours were positive for Bacillus cereus, at levels below 103 CFU/g. Comparing the five municipalities, the concentration of Bacillus cereus was not significantly different (P<0,05). Also, no significant  difference was observed, regardless of the types of flour analyzed. Furthermore, no potentially emetic toxin–producing strains were detected in this work.Keyword : Bacillus cereus, flour, pathogen, emetic strain. French Title: Prevalence de la detection de <i>Bacillus cereus</i> et de souches emetiques dans les farines locales de Cote d'Ivoire Bacillus cereus est un pathogène alimentaire responsable de toxi-infection diarrhéique et émétique. Le syndrome émétique est généralement associé aux aliments farineux. Compte tenu de l’implication des aliments farineux dans les toxi-infections émétiques et de la grande consommation de farines localement produites en Côte d’Ivoire, la prévalence de B. cereus a été évaluée dans cette denrée. 100 échantillons de farines de mil, de maïs et de manioc ont été collectés dans cinq communes d’Abidjan. Des  analyses microbiologiques ont été effectuées conformément à la norme EN ISO 7932: 2004 et à la réglementation européenne CE 2073/2005, afin de dénombrer les Bacillus Cereus et identifier les souches émétiques. Cet pathogène était présent dans 31 (31 % ) des farines de maïs, de mil et de manioc, à des concentrations inférieures à 103 UFC /g. Cette concentration n’est pas significativement différente (p <0,05), d’une commune à l’autre et aucune différence significative n’a été observée, quelque soit le type de farine analysé. Par ailleurs, aucune souche émétique n’a été détectée dans ces farines.Mots clés : Bacillus cereus, farine, pathogène, souche émétique.

Analyse de la diversité floristique du parc national de la Marahoué, Centre-Ouest de la Côte d’Ivoire

La présente étude se propose de caractériser la flore du Parc National dela Marahoué. Nos travaux se sont appuyés sur l’imagerie satellitaire Landsat ETM+ de 2003 pour la description des différents types devégétation et l’inventaire de la flore. La collecte des données sur la flore acombiné la méthode de relevé de surface et celle dite itinérante. Les relevés de surfaces, ont consisté à poser 40 placettes de taille 35x35m,réparties dans les différents types de végétation. Une analyse des données collectées sur le terrain a été effectuée autour de la diversité etla richesse de la flore, mais également de la structure des différents peuplements. On note que le Parc abrite une végétation diversifiéecomposée de forêt dense semi décidue, de forêt dense sèche, de forêt galerie, de savane arbustive. Chaque peuplement est caractérisé par unestructure une diversité et une richesse floristique qui lui sont propres. Ainsi, la flore de la forêt dense semi-décidue est la plus riche et la plusdiversifiée, alors que la forêt galerie est le milieux le plus stable. Au total, 607 espèces végétales subdivisées en 95 familles et 402 genres ont étérelevées. Environ 9% (56 espèces) de cette flore représente des espèces dites endémiques, rares, rares et menacées d’extinction. Cette étude a donc permis de mettre en évidence la richesse et la diversité de la flore du Parc qui doit être protégée.Mots-clés : diversité floristique, végétation, espèces rares et menacées,endémisme, Côte d’Ivoire

Caracterisation des debits d’etiage dans un contexte de changements climatiques : Cas du bassin versant du N'zi (Cote d’Ivoire)

Dans un contexte où les pressions exercées sur les milieux aquatiques et les besoins en eaux des populations ne cessent d’augmenter auquel s’ajoutent les impacts des changements globaux, la connaissance des débits d’étiage constitue un enjeu majeur. L’objectif de cette étude est de caractériser les débits d’étiage du bassin versant du N’zi-Bandama dans l’optique d’une meilleure gestion des ressources en eau de ce bassin. Des données de débits mensuels provenant de cinq stations hydrométriques du fleuve N’zi-Bandama (Fétékro, M’bahiakro, Bocanda, Dimbokro, N’zianouan) ont été utilisées et couvrent la période allant de 1960 à 2016. La méthodologie a consisté à calculer et analyser les seuils de sévérité d’étiage (seuil d’alerte ou QMNA-5, seuil de vigilance et seuil de crise). Les quantiles de débits d’étiage ont été déterminés à partir de la loi lognormale correspondant aux périodes de retour 2, 5, 10, 20 et 50 ans. Les principaux résultats obtenus ont montré que les débits de seuils de sévérité déterminés mettent en évidence la vulnérabilité à de sévères étiages du bassin versant du N’zi-Bandama avec une exposition à la vulnérabilité plus forte pour le sous-bassin versant d’exutoire Fétékro.Mots clés: Débits d’étiage ; QMNA ; Seuils de sévérité ; Bassin versant du N’zi ; Côte d’Ivoire

Antibacterial activity of the aqueous extract of Thonningia sanguinea against Extended-Spectrum-b-Lactamases (ESBL) producing Escherichia coli and Klebsiella pneumoniae strains

Purpose: The aim of this study was to evaluate the antimicrobial activity of Thonningia sanguinea against two sensitive and two multi-drug resistant (ESBL) Enterobacteria strains namely Escherichia coli and Klebsiella pneumoniae. Method: The confirmation of the ESBL producing strains was done by the double-disc synergy tests and the broth dilution method was used for the determination of the antimicrobial parameters (MIC and MBC) on these sensitive and ESBL producing strains. Results: The two sensitive strains had the same MIC and MBC values respectively 3.125 mg /ml and 12.50 mg/ml. The ESBL producing strains also had the same MIC of 6.25 mg /ml and MBC values of 25 mg/ml. The extract was bactericidal for all tested strains. Conclusion: The results suggest that the flowers of T. sanguinea can be used in association with antibiotics for alternative therapy of diseases caused by ESBL producing E. coli, Klebsiella pneumoniae. Keywords: Antimicrobial activity, Thonningia sanguinea, ESBL producing strains; E. coli > Tropical Journal of Pharmaceutical Research Vol. 6 (3) 2007: pp. 779-78

Antagonist potential of Trichoderma indigenous isolates for biological control of Phytophthora palmivora the causative agent of black pod disease on cocoa (Theobroma cacao L.) in Côte d’Ivoire

The biodiversity of Trichoderma isolates from cocoa rhizosphere in cocoa production areas of Côte d’Ivoire, and their antagonist potential with Phytophthora palmivora using in vitro assays and bioassays, were investigated and screened for field trials. A total of 135 isolates were analysed at the species level by using sequence analysis of ITS1 and 2 of the rRNA region and a fragment of translation elongation factor 1a (tef1) gene. Sixty-four isolates were identified as T. virens, 60 as T. harzianum, 7 as T. spirale, two as T. asperellum and two unidentified. Forty-three Trichoderma isolates were in vitro confronted with P. palmivora on agar plates, and their antagonist activity was further evaluated by the damages on leaf discs and detached pods. Twenty-five isolates reduced the mycelial growth of P. Palmivora more than 50%. The isolate T17 assigned to T .virens was the best to reduce mycelium growth upto 97.9%. All of Trichoderma isolates with the exception of isolate T39 reduced foliar sensitivity to P. palmivora. Tweenty-six Trichoderma isolates reduced the pod sensitivity to P. palmivora more than 50%. Based on the combined analysis, T. virens T7, T. harzianum T40, T. asperellum T54 and T. spirale T4 isolates were selected for field trials

Hepatoprotective and antioxidant activities of Hibiscus sabdariffa petal extracts in Wistar rats

Background: Hibiscus sabdariffa is a medicinal plant rich in phytochemical compounds, which is the source of its biological properties. This study on the aqueous extract of H. sabdariffa (AEHS) was conducted to assess its hepatoprotective and antioxidant properties.Methods: It was carried out with 25 Wistar rats divided into five groups. Two groups were treated with a solution of NaCl 0.9%. One group was treated with silymarin at a dose of 25 mg/kg body weight (BW). Two other groups were treated with the AEHS at different doses (100 and 200 mg/kg BW). The treatments were carried out via oral route and at single dose for 7 days. After injection of 2,4-dinitrophenylhydrazine (DNPH), blood samples were collected for the carrying out of biochemical analyses of oxidative stress markers (thiobarbituric acid reactive substances, ferric reduction antioxidant parameter, and 2,2-diphenyl-1-picrylhydrazyl) and hepatotoxicity (albumin, total and direct bilirubin, alanine transaminase, aspartate aminotransferase, and lactate dehydrogenase).Results: Three major results were obtained. The hepatotoxicity of DNPH expressed by the rats of Group 1 was significantly different (p<0.05) from those of the other groups (control, 2-4) for both hepatotoxicity and oxidative stress markers. The hepatoprotective and antioxidant properties of the AEHS and confirmation of those of silymarin through the rats of Groups 2-4 were statistically identical (p<0.05) to the control group for markers of hepatotoxicity and oxidative stress.Conclusion: These results confirm and reinforce certain therapeutic virtues of H. sabdariffa

Phytochemical study and evaluation of the antiviral activity of aqueous extracts of three medicinal plants; Xylopia aethiopica, Gliricidia sepium and Ocimum gratissimum used in Cote d'Ivoire

Background: The present work is part of the exploration of new antiviral molecules to combat antimicrobial resistance. In purpose, this study determined the phytochemical analysis, cytotoxicity and antiviral activity of extracts from three Ivorian medicinal plants; Gliricidia sepium, Ocimum gratissimum and Xylopia aethiopica against poliovirus 1, a non-enveloped RNA virus. Methodology: Aqueous extract of the three plants, which were identified at the herbarium of National Floristic Center Abidjan, was done using a previously described method. The precipitation or staining technique was used to highlight the chemical groups in the three extracts while the polyphenol content of each extract was assessed by the colorimetric method. Cytotoxicity and antiviral activity tests were performed in 96-well plates. Cytotoxicity of each extract on L20B (a genetically engineered mouse cell line) was determined by observation of the cell line carpet. Antiviral activity of three extracts against poliovirus type I was determined after 72 hours using an assay that measures inhibition of the cytopathic effect on cell culture. Results: The three plant extracts contain polyterpenes, sterols and polyphenols, flavonoids, catechetical tannins, saponosides and quinones but none of the extract contains gallic tannins. With the exception of O. gratissimum, alkaloids were found in extracts from the two other plants, and extract of G. sepium was richer in polyphenol than the other two extracts. The cell carpet of L20B after 72 hours contact period with three extracts remained intact at concentrations ranging from 2 to 1000 μg/ml. The aqueous extract of G. sepium showed higher antiviral activity on poliovirus 1 (74.569%) at 2µg/ml than the extracts of O. gratissimum (45.6112%) and X. aethiopica (44.5247%) after 72 hours of incubation. Conclusion: The extract of G. sepium showed potent antiviral activity against poliovirus 1 than that of O. gratissimum and X. aethiopica. This was justified by its higher polyphenol content than the two extracts

Structures, Deformation Mechanisms and Tectonic Phases, Recorded in Paleoproterozoic Granitoids of West African Craton, Southern Part: Example of Kan’s Complex (Central of Côte d’Ivoire)

The granito-gneissic complex of Kan is located in the central part of the Paleoproterozoic domain of Côte d’Ivoire. It consists essentially of migmatitic and mylonitic gneisses with basic intrusions and xenoliths. This Proterozoic domain belongs to the Man Leo shield, southern part of West African craton (WAC). The present study, essentially based on a structural analysis at outcrop scale, aims to identify deformation mechanisms and tectonic phasesrecorded in the granito-gneissic complex of Kan. Deformation mechanisms include: (1) flattening, (2) constriction, (3) simple shear (4), rotation (5), brittle shear, and (6) extension. The Kan complex deformation occurred during four major tectonic phases named D1, D2, D3 and D4. D1 corresponds to WNW-ESE compression. It led to the formation of NS to NNE-SSW foliation, of stretching lineation, and of folds with sub-horizontal axes. It is accompanied by N170° and N10° sinistral shear zones, which constitute globally a NS major transcurrent shear zone in the central part of Côte d’Ivoire. D1 is also marked by N90° dextral shear zones. Tectonic phase D2 is associated with EW compression. It is marked by N50° dextral and N110° sinistral transcurents shear zones. D3 corresponds to NNE-SSW compressive phase and is responsible of N110° crenulation cleavage formation. (D4) constitutes a brittle deformation phase. It correspondsto posteburnean deformation in the Proterozoic crust of Côte d'Ivoire. Generally, these deformation phases are similar to D2 and D3 reported in the Man-Leo shield and that are part of regional collisional phase referred to as Eburnean orogeny in the WAC