118 research outputs found

    Hydro-political assessment of water governance from the top-down and review of literature on local level institutions and practices in the Volta Basin

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    Water resource management / Governance / River basin development / Water law / Colonialism / Institutions / Social participation / Women / Water use

    Cocoa introductions into Ghana

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    Cocoa breeding and selection programmes in Ghana and other West African countries have been based largely on existing cultivated populations or on few collections of wild cocoa. The most widely used cocoa germplasm derives from the material collected by F. J. Pound during the periods 1937-1938 and 1942-1943 and distributed as the Iquitos Mixed Calabacillos (IMC), Nanay, Parinari, Scavina, and the Pound series of clones. This material collected in the Upper Amazon region has been particularly successful, suggesting that cacao would be greatly improved if more germplasm material were provided for use by breeders. Maintaining adequate genetic variability in cocoa germplasm collection, essential for sustainable cocoa production, can be realised through active and conscious germplasm acquisition. Because there is the risk of accidentally introducing diseases and pests along with cocoa germplasm material, effective indexing procedures, together with the availability of final quarantine houses in individual producing countries, are essential to ensure that introduced materials are free of diseases and pests. To be successful as breeding material for producing improved varieties for farmers, the introductions must have some desirable characteristics acceptable to chocolate manufacturers and farmers.Les programmes de reproduction et de sélection de cacao au Ghana et dans d'autres pays de l'Afrique occidentale ont été fondé en grande partie sur les populations de cultures existantes oú sur un tous petit nombre de collections de cacao sauvage. Le germeplasme de cacao le plus utilisé sur une grande étendue vient de matières ramassées par F. J. Pound en 1937-1938 et en 1942-1943 et distribuées sous les noms d'Iquitos Mixed Calabacillos (IMC), Nanay, Parinari, Scavina et Pound comme des séries de clones. Une succès particulier a été réalisé avec cette matière ramassée de la région de Haute Amazone. Ce succès suggère que même de plus grandes améliorations en cacao pourraient être possible si beaucoup auraient été disponible pour utilisation par les phytogéticiens. Le maintien de variabilité génétique adéquate en collection de germeplasme de cacao est essentiel pour la production durable de cacao et ceci pourrait être réalisé par acquisition active et consciente de germeplasme. Puisqu'il y a le risque d'introduire par hasard les maladies et les insectes nuisibles avec la matière de germeplasme du cacao, les procédures efficaces d'indexation, ainsi que la disponibilité de salles de quarantaine finale dans chaque pay producteur sont essentiel pour assurer que les matietes introduietes sont sans maladies et insectes nuisibles. Pour réussir comme matière de reproduction pour la production de variétés améliorés pour les agriculteurs, les introductions devraient avoir quelques caractéristiques désirables er acceptables aux fabriquants de chocolat et aux agriculteurs. Ghana Journal of Agricultural Science Vol. 39 (2) 2006: pp. 22

    Host range, symbiotic effectiveness and nodulation competitiveness of some indigenous cowpea bradyrhizobia isolates from the transitional savanna zone of Ghana

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    To identify indigenous rhizobia with potential as inoculants for increasing cowpea (Vigna unguiculata) yields, we have assessed the host range, symbiotic effectiveness and competitiveness for noduleoccupancy among five (AII-2-1, AII-5-2, AI-4-3, AII-3-4 and BIII-2-2) indigenous cowpea bradyrhizobia isolates from the transitional savanna zone of Ghana. ERIC-PCR DNA fingerprinting patterns were used to identify the isolates occupying nodules. All the isolates nodulated cowpea, groundnut (Arachis hypogeae) and mungbean (Vigna radiata), but only AII-2-1, AII-3-4 and BIII-2-2 nodulated soybean (Glycine max). Apart from cowpea where all the isolates were effective, there were significant differences in the symbiotic effectiveness of the isolates on the other host legumes. Out of a total of about 250 cowpea nodules that were screened for each inoculum-mix, isolate AII-5-2 was the most competitive for nodule occupancy whilst AII-3-4 was the least. Isolate AII-5-2 occupied 71% of the nodules in an inoculum-mix consisting of equal proportions of AII-2-1, AII-5-2 and AI-4-3 (a 3-isolatemix) and 60% of nodules in an inoculum-mix consisting of equal proportions of all the five isolates (a 5- isolate-mix). Therefore, among the isolates tested, AII-5-2 has the best potential for use as inoculant formaximizing cowpea yield in N2- deficient agro-ecological zones of Ghana

    Tool kits for the Sustainable Management of Ghana’s Riverine Biodiversity: an Overveiw

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    The Darwin Initiative funded project Tool kits for the Sustainable Management of Ghana’s Riverine Biodiversity was a collaboration between the Centre for African Wetlands at the University of Ghana, various units of the University of Ghana and the Ghana Wildlife Society. The project also involved collaborators from Burkina Faso, Nigeria, Cote d’Ivoire, Togo and Benin. The project aimed to address the impediments that remain for Ghana (and its neighbouring countries) in applying the Ecosystem Approach (EA) to riverine wetland management and the delivery of the Convention on Biodiversity (CBD). Priority needs were identified as taxonomic capacity building, a contemporary assessment of the status of aquatic biodiversity in Ghana, the development of practical management tools for rivers and increased engagement of stakeholders in decision-making together with an enhanced environmental awareness throughout Ghanaian society. These were addressed in this project by regional and local staff training, reporting on the current status of aquatic communities, the production of educational and taxonomic resources for a range of users, the development of a set of nested indicators of ecosystem health adapted for use at various levels, and the production of a policy document outlining the means of applying the EA in the management of Ghana’s rivers

    Applying SNP marker technology in the cacao breeding programme in Ghana

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    In this investigation 45 parental cacao plants and five progeny derived from the parental stock studied were genotyped using six SNP markers to determine off-types or mislabeled clones and to authenticate crosses made in the Cocoa Research Institute of Ghana (CRIG) breeding programme. Investigation was based on the 5\u2019 nuclease SNPassay using Illustra Hot Start mix Ready-To-Go PCR strips and BioTek FLx800TBP Fluorescence Microplate Reader. In a group of six cacao plants labeled as PA150 clones and another five labeled as Pound7, one clone in each group was unambiguously determined as off-type or mislabeled. Similarly, in a cohort of 23 PA7 "clones", four genotypes were differentiated. Cross-checking the fidelity of five progeny from the parental stock under study, it was established that no errors were made in the crossing. The most significant outcome of this study, however, was that out of the four categories of 23 PA7 candidate parental trees only one category can be comparable to the reference clone in the International Cacao Germplasm collection, Trinidad (ICG,T); thus informing the need for further work to find the correct clone among these for the breeding programme. It was thus concluded that thissimple yet cutting-edge genotyping procedure can be used in applied cocoa breeding programmes in a cocoa producing country. This work represents a first step in the genotypic characterisation of the CRIG germplasm collection and Seed Gardens.Au cours de cette recherche, 45 plants de cacao parentaux et 5 descendants d\ue9rivant du stock parental ont \ue9t\ue9 g\ue9notyp\ue9 en utilisant 6 marqueurs SNP, afin de d\ue9terminer les clones mal \ue9tiquet\ue9s et d\u2019authentifier les croisements effectu\ue9s dans le programme d\u2019am\ue9lioration de l\u2019Institut de Recherche sur le Cacao au Ghana (CRIG). Cette \ue9tude a \ue9t\ue9 bas\ue9e sur les 5' nucl\ue9ases SNP en utilisant des bandes PCR "Hot Start mix Ready-To-Go PCR strips" et un Lecteur Microplat \ue0 Fluorescence "BioTek FLx800TBP". Au sein d\u2019un groupe de six plants de cacao \ue9tiquet\ue9 PA150 et d\u2019un autre groupe de cinq \ue9tiquet\ue9 Pound 7, il a \ue9t\ue9 d\ue9termin\ue9 sans ambigu\ueft\ue9 qu\u2019un clone par groupe \ue9tait mal \ue9tiquet\ue9. De fa\ue7on similaire, quatre g\ue9notypes diff\ue9rents ont \ue9t\ue9 identifi\ue9s dans une m\ueame cohorte de clones 23PA7. En v\ue9rifiant la fid\ue9lit\ue9 de cinq descendants issus du stock parental \ue9tudi\ue9, il a \ue9t\ue9 \ue9tabli qu\u2019aucune erreur n\u2019avait \ue9t\ue9 faite lors du croisement. Le r\ue9sultat le plus significatif de cette \ue9tude a \ue9t\ue9 que, sur quatre cat\ue9gories de 23 candidats PA7 de souches parentales, une seule pouvait \ueatre comparable au clone de r\ue9f\ue9rence dans la collection Internationale du Germoplasme de Cacao, Trinidad (ICG,T), d\ue9montrant ainsi la n\ue9cessit\ue9 de travaux suppl\ue9mentaires pour d\ue9terminer le clone exact parmi ceux \ue9voqu\ue9s pr\ue9c\ue9demment. Il a ainsi \ue9t\ue9 conclu que cette m\ue9thode avant-gardiste de g\ue9notypage, pourtantsimple, peut \ueatre utilis\ue9e dans les programmes appliqu\ue9s d\u2019am\ue9lioration du cacao dans un pays producteur. Ce travail repr\ue9sente une premi\ue8re \ue9tape dans la caract\ue9risation g\ue9n\ue9tique de la collection du germoplasme CRIG et jardins semenciers

    Afucosylated Plasmodium falciparum-specific IgG is induced by infection but not by subunit vaccination

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    Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family members mediate receptor- and tissue-specific sequestration of infected erythrocytes (IEs) in malaria. Antibody responses are a central component of naturally acquired malaria immunity. PfEMP1-specific IgG likely protects by inhibiting IE sequestration and through IgG-Fc Receptor (FcγR) mediated phagocytosis and killing of antibody-opsonized IEs. The affinity of afucosylated IgG to FcγRIIIa is up to 40-fold higher than fucosylated IgG, resulting in enhanced antibody-dependent cellular cytotoxicity. Most IgG in plasma is fully fucosylated, but afucosylated IgG is elicited in response to enveloped viruses and to paternal alloantigens during pregnancy. Here we show that naturally acquired PfEMP1-specific IgG is strongly afucosylated in a stable and exposure-dependent manner, and efficiently induces FcγRIIIa-dependent natural killer (NK) cell degranulation. In contrast, immunization with a subunit PfEMP1 (VAR2CSA) vaccine results in fully fucosylated specific IgG. These results have implications for understanding protective natural- and vaccine-induced immunity to malaria

    Afucosylated Plasmodium falciparum-specific IgG is induced by infection but not by subunit vaccination

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    Here, Larsen et al. describe differences in Fc fucosylation of P. falciparum PfEMP1-specific IgG produced in response to natural infection versus VAR2CSA-type subunit vaccination, which leads to differences in the ability to induce Fc gamma RIIIa-dependent natural killer cell degranulation.Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family members mediate receptor- and tissue-specific sequestration of infected erythrocytes (IEs) in malaria. Antibody responses are a central component of naturally acquired malaria immunity. PfEMP1-specific IgG likely protects by inhibiting IE sequestration and through IgG-Fc Receptor (Fc gamma R) mediated phagocytosis and killing of antibody-opsonized IEs. The affinity of afucosylated IgG to Fc gamma RIIIa is up to 40-fold higher than fucosylated IgG, resulting in enhanced antibody-dependent cellular cytotoxicity. Most IgG in plasma is fully fucosylated, but afucosylated IgG is elicited in response to enveloped viruses and to paternal alloantigens during pregnancy. Here we show that naturally acquired PfEMP1-specific IgG is strongly afucosylated in a stable and exposure-dependent manner, and efficiently induces Fc gamma RIIIa-dependent natural killer (NK) cell degranulation. In contrast, immunization with a subunit PfEMP1 (VAR2CSA) vaccine results in fully fucosylated specific IgG. These results have implications for understanding protective natural- and vaccine-induced immunity to malaria.Proteomic
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