Troisième cours international portant sur la microbiologie de M. ulcerans (M2U) à Yaoundé

International audienc

Characterization and Bioremediation of Birch Condensate

Birch (Betula papyrifera Marsh) condensate collected from a veneer plant in Michigan was analyzed for its major chemical constituents. This condensate contained carbohydrates and lipids. In the lipid fractions, triglycerides were the most abundant component (35-40%), followed by phenolic compounds (30%) and waxes (25-30%). Gas Chromatography-Mass Spectrometry (GC-MS) and Fast Atom Bombardment (FAB) MS were used to identify 14 lipid compounds. A white rot fungus, Phanerochaete chrysosporium [Burdsall-lombard, 5176, HHB-6251], was tested as a means for the bio-remediation of the condensate. P. chrysosporium reduced the total organic content (TOC) of the condensate from 350 ppm to 22 ppm and the color intensity from 0.614 to 0.355 absorbance units, after 2 weeks incubation in a liquid medium containing yeast and peptonc at pH 5

Crises epileptiques au cours de la toxoplasmose cerebrale chez les patients immunodeprimes au vih.

Objectif Décrire les caractéristiques des crises épileptiques au cours de la toxoplasmose cérébrale (TC) chez les patients immunodéprimés au VIH à l’Hôpital Général de Douala (HGD).Matériel méthodesIl s’agissait d’une étude descriptive rétrospective des cas de TC diagnostiquée entre janvier 2000 et décembre 2012. La prévalence, le type, la fréquence des crises épileptiques et les thérapeutiques antiépileptiques ont été étudiées. Les patients avec un antécédent de crises épileptiques étaient exclus. Le test de Khi-2 a été utilisé pour rechercher les facteurs associés à la survenue des crises épileptiques tandis que le test de Student a été utilisé pour comparer les moyennes. P < 0,05 était considéré comme statistiquement significatif.Résultats 146 patients étaient inclus avec 78 femmes pour un sex-ratio de 0,87 en faveur des femmes. L’âge moyen était de 39,38 ± 9,88 ans. Le taux de CD4 moyen était de 115,63 ± 142,70 éléments/ml. La prévalence des crises épileptiques était de 45,2% et 61% des épileptiques étaient répétées. Les crises épileptiques généralisées prédominaient avec 75,8%. Seuls la fièvre (p < 0,012), les céphalées (p < 0,004), le syndrome d’hypertension intracrânienne (p < 0,038), un taux de CD4 < 50/ mm3 (p < 0,02) et un taux d’hémoglobine < 10g/dl (p < 0,017) étaient statistiquement associés à la survenue des crises épileptiques. Un traitement antiépileptique était prescrit chez 43,2% des patients.Conclusion Les crises épileptiques sont fréquentes au cours de la toxoplasmose cérébrale. Elles peuvent se répéter et justifier d’un traitement antiépileptique.Mots clés : Toxoplasmose cérébrale, VIH, Crises épileptiques, Douala, Cameroun

Plasma Letrozole Concentrations in Postmenopausal Women With Breast Cancer Are Associated With CYP2A6 Genetic Variants, Body Mass Index, and Age

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109858/1/cptclpt2011174.pd

Melanin production inhibitors from the West African 'Cassipourea congoensis'

Cassipourea congoensis (syn. Cassipourea malosana) is used in African countries as a skin-lightening agent. Two previously unreported cycloartane triterpenoids, 26-hydroxy-3-keto-24-methy lenecycloartan-30-oic acid 1 and 24-methylene-cycloartan-3β,26,30-triol 2 along with the known mahuannin B 3, 7-methoxymahuannin B 4, 7-methoxygeranin A 5, methyl-3-(4-hydroxy-3-methoxyphenyl)-2E-propenoate, glycerol-1-alkanoate, (E)-3-(4-hydroxy-3-methoxyphenyl)prop-2-enal 6, (-)-syringaresinol 7, and stigmast-5-en-3-O-β-D-glucoside, were isolated from the roots of C. congoensis. The crude extract and compounds 1 and 5 were found to inhibit the production of melanin at 10 μM with low cytotoxicity validating the ethno-medicinal use of this plan

Ethnoknowledge of medicinal and mystical plants used by healers in Juazeiro do Norte, Ceará, Northeast Brazil

154-166The aim of this study was to investigate the use of medicinal plants by healers in Juazeiro do Norte, Northeast Brazil, as well as to understand their role in prayer/healing practices. 30 residents from 20 neighborhoods, 18 urban neighborhoods and 2 randomly selected rural locations, were interviewed using a sample method known as "snowball", with two pilot interviews being initially conducted, where for greater method reliability and for the analysis of the importance attributed to the plants by the respondents, a calculation to determine their Relative Importance (RI) index was used. The results indicate the use of 60 species distributed across 34 families. The most representative families were: Fabaceae (7), Lamiaceae (6) and Asteraceae (5), where 10 species (eight exotic and two native) obtained a Relative Importance (RI>1): Ruta graveolens L. (1.47), Vernonia condensata Baker (1.47), Piper aduncun L. (1.44), Mentha spicata L. (1.33), Myracrodruon urundeuva Allemão (1.3), Psidium guajava L. (1.19), Hymenaea stignocarpa Mart. ex. Hayne (1.15), Lippia alba (Mil.) (1.11), Leonotis nepetaefolia (L.) R. Br. (1.08) and Cymbopogon citratus (D.C.) Stapf (1.01). The aforementioned species are acquired from backyards (50%), open markets (33.3%) or from surrounding scrubs (16.6%). Indications included usage for 11 body systems, with 36 species (60%) being indicated for the treatment of the digestive system and 15 (25%) for the treatment of diseases of the female reproductive system. Nine species (15%) were indicated for ritualistic purposes (prayer/healing). With this, the importance of the Healer figure in several municipal districts was observed, a tradition that remains alive, despite the need for greater transmission and assimilation to upcoming generations

Roadless wilderness area determines forest elephant movements in the Congo Basin

A dramatic expansion of road building is underway in the Congo Basin fuelled by private enterprise, international aid, and government aspirations. Among the great wilderness areas on earth, the Congo Basin is outstanding for its high biodiversity, particularly mobile megafauna including forest elephants (Loxodonta africana cyclotis). The abundance of many mammal species in the Basin increases with distance from roads due to hunting pressure, but the impacts of road proliferation on the movements of individuals are unknown. We investigated the ranging behaviour of forest elephants in relation to roads and roadless wilderness by fitting GPS telemetry collars onto a sample of 28 forest elephants living in six priority conservation areas. We show that the size of roadless wilderness is a strong determinant of home range size in this species. Though our study sites included the largest wilderness areas in central African forests, none of 4 home range metrics we calculated, including core area, tended toward an asymptote with increasing wilderness size, suggesting that uninhibited ranging in forest elephants no longer exists. Furthermore we show that roads outside protected areas which are not protected from hunting are a formidable barrier to movement while roads inside protected areas are not. Only 1 elephant from our sample crossed an unprotected road. During crossings her mean speed increased 14-fold compared to normal movements. Forest elephants are increasingly confined and constrained by roads across the Congo Basin which is reducing effective habitat availability and isolating populations, significantly threatening long term conservation efforts. If the current road development trajectory continues, forest wildernesses and the forest elephants they contain will collapse

Resistance of African tropical forests to an extreme climate anomaly.

The responses of tropical forests to environmental change are critical uncertainties in predicting the future impacts of climate change. The positive phase of the 2015-2016 El Niño Southern Oscillation resulted in unprecedented heat and low precipitation in the tropics with substantial impacts on the global carbon cycle. The role of African tropical forests is uncertain as their responses to short-term drought and temperature anomalies have yet to be determined using on-the-ground measurements. African tropical forests may be particularly sensitive because they exist in relatively dry conditions compared with Amazonian or Asian forests, or they may be more resistant because of an abundance of drought-adapted species. Here, we report responses of structurally intact old-growth lowland tropical forests inventoried within the African Tropical Rainforest Observatory Network (AfriTRON). We use 100 long-term inventory plots from six countries each measured at least twice prior to and once following the 2015-2016 El Niño event. These plots experienced the highest temperatures and driest conditions on record. The record temperature did not significantly reduce carbon gains from tree growth or significantly increase carbon losses from tree mortality, but the record drought did significantly decrease net carbon uptake. Overall, the long-term biomass increase of these forests was reduced due to the El Niño event, but these plots remained a live biomass carbon sink (0.51 ± 0.40 Mg C ha-1 y-1) despite extreme environmental conditions. Our analyses, while limited to African tropical forests, suggest they may be more resistant to climatic extremes than Amazonian and Asian forests

Evolution of a supergene that regulates a trans-species social polymorphism

Supergenes are clusters of linked genetic loci that jointly affect the expression of complex phenotypes, such as social organization. Little is known about the origin and evolution of these intriguing genomic elements. Here we analyse whole-genome sequences of males from native populations of six fire ant species and show that variation in social organization is under the control of a novel supergene haplotype (termed Sb), which evolved by sequential incorporation of three inversions spanning half of a 'social chromosome'. Two of the inversions interrupt protein-coding genes, resulting in the increased expression of one gene and modest truncation in the primary protein structure of another. All six socially polymorphic species studied harbour the same three inversions, with the single origin of the supergene in their common ancestor inferred by phylogenomic analyses to have occurred half a million years ago. The persistence of Sb along with the ancestral SB haplotype through multiple speciation events provides a striking example of a functionally important trans-species social polymorphism presumably maintained by balancing selection. We found that while recombination between the Sb and SB haplotypes is severely restricted in all species, a low level of gene flux between the haplotypes has occurred following the appearance of the inversions, potentially mitigating the evolutionary degeneration expected at genomic regions that cannot freely recombine. These results provide a detailed picture of the structural genomic innovations involved in the formation of a supergene controlling a complex social phenotype