Palm wine harvesting by the Bassari threatens Borassus aethiopum populations in north-western Guinea

The use of the palm tree Borassus aethiopum Mart(Coryphoideae) by the Bassari ethnic group in the Republic of Guinea wasstudied. Ethnic groups have multiple uses for B. aethiopumthroughout its distribution in tropical Africa. The Bassari use this palm mostlyas a palm wine resource. As their harvesting technique leads to the death of thepalm, the populations of this species are highly endangered in the areapopulated by the Bassari. The fast decline of an important resource has recentlygained attention at governmental level. In order to conserve the populations ofthis palm, it is essential to understand whether the Bassari use a lethaltechnique because of socio-economic reasons or due to a lack of knowledge. Thepresent study aims to answer this question. We collected the data in thenorth-western part of the Republic of Guinea in May 1996 by field observationsand by using 'Rapid Rural Appraisal' tools consisting of interactiveinterviews with palm wine harvesters, collectors, carriers and sellers. Afterconstructing a woody ladder fixed to the stem the Bassari extract the sap bycutting a hole into the palm heart and by removing a small part of the palmheart two times per day. Individual trees produce on average 10 lper day. After 35–45 days the sap production ceases and thepalm dies. A harvester kills on average 56 individuals of B.aethiopum per year. As a consequence of this lethal techniqueexploiters have to constantly move through and between palm populations. Thereis no reforestation of the degraded areas. The palm wine extraction ofB. aethiopum is the main activity of the Bassari for 7months of the year. For harvesters, collectors, carriers andsellers, palm wine extraction provides one of the most important annual incomes.The harvester pays a monthly tax of USD 5 to the forestry administration.Despite its economic importance, the Bassari palm wine harvesters rangeB. aethiopum as the sixth most important plant species in the area. The paradoxical situation of acommunity that threatens a resource that it is highly dependent on may beexplained by the following circumstances. Firstly, the exploiters seek a maximumprofit on a short term basis. Secondly, the exploiters apparently do not takeinto consideration the total value of other potential products from theBorassus. Thirdly, the Bassari do not have an importanttradition for exploiting B. aethiopum so that there is noapparent cultural alliance between the Bassari and the palm. Finally, the rulesand regulations for harvesting Borassus products favourquick profit. The extinction of the palm population studied can be expectedwithin about 25 years if no protection measure is taken.     

La tumeur adénomatoïde de l’épididyme: A propos d’un cas

We report the first case of adenomatoid tumor of the epididymis diagnosed in Senegal. A 41-years old man was referred to us for severe scrotal pain in the left side. Physical examination discovered a left scrotal mass. An epididymectomy was perfomed. Histological analysis of the surgical specimen with immunohistochemical staining confirmed an adenomatoid tumor. Tumors of the epididymis are frequently benign, therefore a conservative approach is recommended.     

Improving heat stability of haemagglutinating antigens for avian influenza

The increasing demand for avian influenza diagnostic reagents worldwide, has included requests for significant supplies of product to developing countries. Difficulties in dispatching to remote areas and tropical countries are a major concern to suppliers, international organisations and donors as delays in forwarding parcels often result in storage at non-optimal or inadequate temperatures results in loss in titre and thus wastage of resources.In this study we demonstrate that the heat stability of avian influenza haemagglutination inhibition antigens of the H5, H7 and H9 subtype following 14 days of exposure to 37 °C and 45 °C is significantly increased by adding D-(+)-Trehalose to the freshly prepared antigen. Increased stability was detected both for freeze-dried antigens over an extended period of 6 months and also in heat exposed antigens that were then stored at +4 C for up to 35 days post reconstitution.     

Insecticide resistance status and mechanisms in Aedes aegypti populations from Senegal

Aedes aegypti is the main epidemic vector of arboviruses in Africa. In Senegal, control activities are mainly limited to mitigation of epidemics, with limited information available for Ae. aegypti populations. A better understanding of the current Ae. aegypti susceptibility status to various insecticides and relevant resistance mechanisms involved is needed for the implementation of effective vector control strategies. The present study focuses on the detection of insecticide resistance and reveals the related mechanisms in Ae. aegypti populations from Senegal.Bioassays were performed on Ae. aegypti adults from nine Senegalese localities (Matam, Louga, Barkedji, Ziguinchor, Mbour, Fatick, Dakar, Kédougou and Touba). Mosquitoes were exposed to four classes of insecticides using the standard WHO protocols. Resistance mechanisms were investigated by genotyping for pyrethroid target site resistance mutations (V1016G, V1016I, F1534C and S989P) and measuring gene expression levels of key detoxification genes (CYP6BB2, CYP9J26, CYP9J28, CYP9J32, CYP9M6, CCEae3a and GSTD4).All collected populations were resistant to DDT and carbamates except for the ones in Matam (Northern region). Resistance to permethrin was uniformly detected in mosquitoes from all areas. Except for Barkédji and Touba, all populations were characterized by a susceptibility to 0.75% Permethrin. Susceptibility to type II pyrethroids was detected only in the Southern regions (Kédougou and Ziguinchor). All mosquito populations were susceptible to 5% Malathion, but only Kédougou and Matam mosquitoes were susceptible to 0.8% Malathion. All populations were resistant to 0.05% Pirimiphos-methyl, whereas those from Louga, Mbour and Barkédji, also exhibited resistance to 1% Fenitrothion. None of the known target site pyrethroid resistance mutations was present in the mosquito samples included in the genotyping analysis (performed in > 1500 samples). In contrast, a remarkably high (20-70-fold) overexpression of major detoxification genes was observed, suggesting that insecticide resistance is mostly mediated through metabolic mechanisms. These data provide important evidence to support dengue vector control in Senegal.     

The <Emphasis Type="Italic">disarrayed</Emphasis> mutation results in cell cycle and neurogenesis defects during retinal development in zebrafish

Background  

The vertebrate retina is derived from proliferative neuroepithelial cells of the optic cup. During retinal development, cell proliferation and the processes of cell cycle exit and neurogenesis are coordinated in neuroepithelial progenitor cells. Previous studies have demonstrated reciprocal influences between the cell cycle and neurogenesis. However the specific mechanisms and exact relationships of cell cycle regulation and neurogenesis in the vertebrate retina remain largely unknown.