Soluble extracts from salivarian trypanosomes (Trypanosoma brucei brucei, T. evansi and T. congolense) were shown to be capable of inducing murine tumour necrosis factor (mTNF) secretion, both in vivo and in vitro, whereas the soluble extract of an intracellular trypanosome (T. cruzi) failed to do so. Furthermore, the role of mTNF during the initial phase of experimental infections with T. brucei was studied by treating infected mice with mTNF-inducing trypanosoma soluble extract and with neutralizing monoclonal anti-mTNF antibodies. Treatment of the infected animals with different doses of T. brucei soluble extract resulted in a lower first parasitaemia peak (low lysate dose) and in a longer survival time or in a nearly total inhibition of parasite development (high lysate dose). Cotreatment of the infected mice with both anti-mTNF antibodies and a high dose of soluble extract completely restored the parasite development in both trypanosusceptible C3H/He mice and trypanosubtolerant CBA Ca mice, indicating a protective role of mTNF during the parasitaemia. Collectively these results suggest a negative influence of mTNF on T. brucei development in vivo.

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This study was carried out to evaluate the potential of the use of predominant yeast strains (Sacharomyces cerevisiae and Issatkenkia orientalis) and lactic acid bacteria (Lactobacillus fermentum) of Rwandese traditional sorghum beer "ikigage" as starter cultures to improve ikigage beer. The results show that L. fermentum has an influence on taste sour of ikigage beer and contributes also to generating ethyl acetate, ethyl lactate and higher alcohols such as 3-methylbutan-1-ol, 2-methylbutan-1-ol and 2-methylpropan-1-ol of this beer. I. orientalis contributed to the production of ethyl butyrate, ethyl caprylate, isobutyl butyrate and their corresponding acids, and to the generation of phenyl alcohols in ikigage beer. The association of S. cerevisiae with I. orientalis and L. fermentum produced ikigage beer with taste, aroma and mouth feel more similar to ikigage beers brewed locally by peasants. It is recommended to use S. cerevisiae in association with L. fermentum and I. orientalis as stater cultures to produce ikigage beer having the uniform organoleptic characteristics and a high ethanol content. This method also reduces the risk of contamination of the brew with food sanitary indicator and pathogenic microorganisms and will increase the chance of preservation of ikigage beer.

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