Histological review of skin cancers in African Albinos: a 10-year retrospective review.

BACKGROUND Skin cancer is rare among Africans and albinism is an established risk for skin cancer in this population. Ultraviolet radiation is highest at the equator and African albinos living close to the equator have the highest risk of developing skin cancers. METHODS This was a retrospective study that involved histological review of all specimens with skin cancers from African albinos submitted to The Regional Dermatology Training Center in Moshi, Tanzania from 2002 to 2011. RESULTS A total of 134 biopsies from 86 patients with a male to female ratio of 1:1 were reviewed. Head and neck was the commonest (n = 75, 56.0%) site affected by skin cancers. Squamous cell carcinoma (SCC) was more common than basal cell carcinoma (BCC) with a ratio of 1.2:1. Only one Acral lentiginous melanoma was reported. Majority (55.6%) of SCC were well differentiated while nodular BCC (75%) was the most common type of BCC. CONCLUSIONS Squamous cell carcinoma is more common than basal cell carcinoma in African albinos.

Characterization of choline uptake in Trypanosoma brucei and involvement of a mitochondrial carrier in resistance to choline analogs

Choline is an essential nutrient for eukaryotic cells, where it is used as precursor for the synthesis of choline-­containing phospholipids, such as phosphatidylcholine (PC). Our experiments showed – for the first time – that Trypanosoma brucei, the causative agent of human African sleeping sickness, is able to take up choline from the culture medium to use for PC synthesis, indicating that trypanosomes express a transporter for choline at the plasma membrane. Further characterization in procyclic and bloodstream forms revealed that choline uptake is saturable and can be inhibited by HC-3, a known inhibitor of choline uptake in mammalian cells. To obtain additional insights on choline uptake and metabolism, we investigated the effects of choline-analogs that were previously shown to be toxic for T. brucei parasites in culture. Interestingly, we found that all analogs tested effectively inhibited choline uptake into both bloodstream and procyclic form parasites. Subsequently, selected compounds were used to search for possible candidate genes encoding choline transporters in T. brucei, using an RNAi library in bloodstream forms. We identified a protein belonging to the mitochondrial carrier family, previously annotated as TbMCP14, as prime candidate. Down‐regulation of TbMCP14 by RNAi prevented drug-­induced loss of mitochondrial membrane potential and conferred 8­‐fold resistance of T. brucei bloodstream forms to choline analogs. Conversely, over‐expression of the carrier increased parasite susceptibility more than 13-­fold. However, subsequent experiments demonstrated that TbMCP14 was not involved in metabolism of choline. Instead, growth curves in glucose‐depleted medium using RNAi or knock‐out parasites suggested that TbMCP14 is involved in metabolism of amino acids for energy production. Together, our data demonstrate that the identified member of the mitochondrial carrier family is involved in drug uptake into the mitochondrion and has a vital function in energy production in T. brucei.

Functional proteomics and biochemsitry: working together to unravel mitochondrial phenomena of African trypansomes

Central to the understanding of how mitochondria control their morphology, communicate with their surroundings and manage exchange of metabolites and transport of biopolymers (proteins, RNAs) is the mitochondrial outer membrane (MOM), as the MOM defines the boundary of the organelle. Recently, we have purified the MOM of the mitochondrial model organism T. brucei and characterized its proteome. Our results show that the trypanosomal MOM proteome consists of 82 proteins. Among these, we identified novel factors required to regulate mitochondrial morphology and the long-elusive protein import machinery of T. brucei. A comparison with the MOM proteome of yeast defines a set of 17 common proteins that are likely present in the mitochondrial outer membrane of all eukaryotes. One of these is the Miro-GTPase Gem1. In yeast, this Ca2+-EF-Hand containing polypeptide is thought to be involved in a protein complex that physically tethers the mitochondrion to the ER. In mammalian cells, a putative tethering complex was linked to the mitochondrial fusion/fission machinery. Thus, the concept of a protein complex-mediated connection seems to be a general and conserved feature. We are currently investigating if such a protein complex exists in T. brucei and if the trypanosomal Gem1 protein is involved.

Attitudes and Beliefs of Pig Farmers and Wild Boar Hunters Towards Reporting of African Swine Fever in Bulgaria, Germany and the Western Part of the Russian Federation

This study investigated the attitudes and beliefs of pig farmers and hunters in Germany, Bulgaria and the western part of the Russian Federation towards reporting suspected cases of African swine fever (ASF). Data were collected using a web-based questionnaire survey targeting pig farmers and hunters in these three study areas. Separate multivariable logistic regression models identified key variables associated with each of the three binary outcome variables whether or not farmers would immediately report suspected cases of ASF, whether or not hunters would submit samples from hunted wild boar for diagnostic testing and whether or not hunters would report wild boar carcasses. The results showed that farmers who would not immediately report suspected cases of ASF are more likely to believe that their reputation in the local community would be adversely affected if they were to report it, that they can control the outbreak themselves without the involvement of veterinary services and that laboratory confirmation would take too long. The modelling also indicated that hunters who did not usually submit samples of their harvested wild boar for ASF diagnosis, and hunters who did not report wild boar carcasses are more likely to justify their behaviour through a lack of awareness of the possibility of reporting. These findings emphasize the need to develop more effective communication strategies targeted at pig farmers and hunters about the disease, its epidemiology, consequences and control methods, to increase the likelihood of early reporting, especially in the Russian Federation where the virus circulates

Simulating Carbon Stocks and Fluxes of an African Tropical Montane Forest with an Individual-Based Forest Model

Tropical forests are carbon-dense and highly productive ecosystems. Consequently, they play an important role in the global carbon cycle. In the present study we used an individual-based forest model (FORMIND) to analyze the carbon balances of a tropical forest. The main processes of this model are tree growth, mortality, regeneration, and competition. Model parameters were calibrated using forest inventory data from a tropical forest at Mt. Kilimanjaro. The simulation results showed that the model successfully reproduces important characteristics of tropical forests (aboveground biomass, stem size distribution and leaf area index). The estimated aboveground biomass (385 t/ha) is comparable to biomass values in the Amazon and other tropical forests in Africa. The simulated forest reveals a gross primary production of 24 tcha-1yr-1. Modeling above- and belowground carbon stocks, we analyzed the carbon balance of the investigated tropical forest. The simulated carbon balance of this old-growth forest is zero on average. This study provides an example of how forest models can be used in combination with forest inventory data to investigate forest structure and local carbon balances.

Resilient Adaptation to Climate Change in African Agriculture

Africa’s agriculture faces varying climate change impacts which mainly worsen production conditions and adversely affect its economies. Adaptations thus need to build the resilience of farming systems. Using “resilient adaptation” as a concept, this study analyses how adaptations at farm and policy/institutional-levels contribute to the resilience of Sub-Saharan African agriculture. The developed tool, “the Resilience Check”, provides socio-economic data which complements existing adaptation tools. The underlying development gaps such as insecure property rights, poverty, low self-organisation, inadequate climate data and infrastructure limit resilient adaptations. If farmers could implement recommended practices, existing measures and improved crops can address most impacts expected in the medium-term. However, resource use efficiency remains critical for all farm management types. Development-oriented adaptation measures are needed to provide the robust foundations for building resilience. Reaching the very poor remains a challenge and the externally driven nature of many interventions raises concern about their sustainability. The study recommends practical measures such as decentralising various services and integrating the action plans of the multilateral environmental agreements into one national action plan.

Legal Aspects of Sino-­African Tied Aid: The Art of Playing with a Legal Grey Area

Sino-African trade has seen a fifty-fold increase in the years 1999 to 2008. In some African regions, particularly in sub-Saharan Africa, China has even replaced the US as the most important trading partner today. But China holds not a single FTA on the African continent, while other major trading partners of African economies rely on an extensive framework of different trade agreements. What is, thus, the legal basis of the recent increase of Sino-African trade? Interestingly, Sino-African trade has seen a particularly strong increase in countries that have entered into tied aid agreements with China. These agreements are commonly known under the term ‘Angola-Model’ and consist of a multifaceted network of barter-trading-systems, aspects of tied aid and concessions for oil and other commodities linked with a state loan. It is likely that these agreements have an impact on the trade-flows between African countries and China. This paper discusses the legal character of this new form of economic cooperation, or modern version of tied aid. Critical legal aspects related to this form of tied aid refer to violation of the principle of most-favoured nation (MFN), illegitimate export subsidies, market access, public procurement and transparency in the international trading system. However, despite the recent outcry of the foremost Western community against the strategy of the Chinese government on the African continent, the practice of the Angola-Model based tied aid is not entirely new, and neither is it against the law. The case of tied aid is situated in a legal grey area that should be examined thoroughly in order to strengthen the international trading system and to support developing countries in their attempt to gain from tied aid arrangements.