Derivatives of chitin oligosaccharides have been shown to play a role in plant organogenesis at nanomolar concentrations. Here we present data which indicate that chitin oligosaccharides are... Show moreDerivatives of chitin oligosaccharides have been shown to play a role in plant organogenesis at nanomolar concentrations. Here we present data which indicate that chitin oligosaccharides are important for embryogenesis in vertebrates. We characterize chitin oligosaccharides synthesized in vitro by zebrafish and carp embryos in the late gastrulation stage by incorporation of radiolabeled N-acetyl-D-[(UC)-C-14]glucosamine and by HPLC in combination with enzymatic conversion using the Bradyrhizobium NodZ alpha-1,6-fucosyltransferase and chitinases. A rapid and sensitive bioassay for chitin oligasaccharides was also used employing suspension-cultured plant cells of Catharanthus roseus. We show that chitin oligosaccharide synthase activity is apparent only during late gastrulation and can be inhibited by anti-serum raised against the Xenopus DG42 protein. The DG42 protein, a glycosyltransferase, is transiently expressed between midblastula and neurulation in Xenopus and zebrafish embryogenesis. Microinjection of the DG42 antiserum or the Bradyrhizobium NodZ enzyme in fertilized eggs of zebrafish led to severs defects in trunk and tail development. Show less
The root of the 'anglophone problem' in Cameroon may be traced back to 1961, when the political elites of two territories with different colonial legacies - one French and the other British -... Show moreThe root of the 'anglophone problem' in Cameroon may be traced back to 1961, when the political elites of two territories with different colonial legacies - one French and the other British - agreed on the formation of a federal State. Contrary to expectations, this did not provide for the equal partnership of both parties, let alone for the preservation of the cultural heritage and identity of each, but turned out to be merely a transitory phase to the total integration of the anglophone region into a strongly centralized, unitary State. Gradually, this created an anglophone consciousness: the feeling of being marginalized by the francophone-dominated State. In the wake of political liberalization in the early 1990s, anglophone interests came to be represented first and foremost by various associations and pressure groups that initially demanded a return to the federal State. It was only after the persistent refusal of the Biya government to discuss this scenario that secession became an overt option with mounting popularity. The government's determination to defend the unitary State by all available means, including repression, could lead to an escalation of anglophone demands past a point of no return. Notes, ref Show less
Schadeberg, T.C.; Mreta, A.Y.; Scheckenbach, G. 1997
The natural environment of the Kenyan coast is threatened in many ways. A study day was organized on August 7, 1996, by the School of Environmental Studies, Moi University, Eldoret, with... Show moreThe natural environment of the Kenyan coast is threatened in many ways. A study day was organized on August 7, 1996, by the School of Environmental Studies, Moi University, Eldoret, with presentations on the activities and research priorities of organizations concerned with coastal environment issues. This report contains presentations on district environment management by Henry Munga'sia; the Coast Development Authority by Bonfance Mwandotto; maritime research priorities for the Kenya Marine and Fisheries Research Institute, by Enock Wakwabi; the marine programmes of the Kenya Wildlife Service, by Nyawira Muthiga; the wetlands conservation project of the Kenya Wildlife Service, by Els Martens; small fisheries research in Kwale District, by Anthony King and Delphine Malleret-King; priorities in botanical research in coastal Kenya, by S. Ann Robertson; Kaya Forest conservation on the Kenya coast, by Anthony Githito; wasteland rehabilitation, by Sabine Baer; activities of the International Centre of Insect Physiology and Ecology, by Srinivasan Sithanantham & Z. Ngalo Otieno; activities of the Kenya Agricultural Research Institute, by Geoffrey Kamau; the Coral Reef Conservation Project, by Nyawira Muthiga and Tim McClanahan; and the training course on Fundamental and Applied Marine Ecology of the Free University of Brussels, by Nanette Daro Show less
Dit cahier bevat bijdragen van verschillende auteurs. Na een algemene inleiding over democratiseringsprocessen en de rol van de media in Afrika, volgt een aantal landenoverzichten die met name... Show moreDit cahier bevat bijdragen van verschillende auteurs. Na een algemene inleiding over democratiseringsprocessen en de rol van de media in Afrika, volgt een aantal landenoverzichten die met name aandacht besteden aan de recente ontwikkelingen binnen pers, radio en televisie, persvrijheid en eigendomsverhoudingen in Angola, Botswana, Malawi, Mozambique, Namibië, Zambia, Zimbabwe en Zuid-Afrika. Tot slot volgt een bijdrage over vrouwen, media en democratie. Aan de uitgave werd meegewerkt door Petra Willemsteijn, Berendien Bos en Ineke van Kessel. Show less
This paper examines strategies used by rural households in Ntcheu District, Malawi, to cope with a decreasing fuelwood availability. Fieldwork was carried out in 1990 and 1991. With increasing... Show moreThis paper examines strategies used by rural households in Ntcheu District, Malawi, to cope with a decreasing fuelwood availability. Fieldwork was carried out in 1990 and 1991. With increasing distance to woodlands, households initially collected further away, spending more time on collection. But when distance to woodlands increased further, households returned to nearby places using less time for collection and switching to lower quality woods. Results indicate that distance to collection place and collection time are not reliable indicators of fuelwood shortages. Households within the same village differed in collection strategies particularly as regards collection distance and collection frequency. Households that tended to collect further away and more frequently were large in size with more female adults. These households also collected more wood, even per capita, compared to smaller households, suggesting that smaller households economized on fuelwood use. This paper supports the idea that level of fuelwood used is not only determined by fuelwood availability, but more by labour availability. Show less
