Browsing by Author "Elibariki, Gladness"

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    Molecular characterization of fungi associated with a traditionally fermented banana food from north-eastern, Tanzania
    (University of Dar es Salaam, 2006) Elibariki, Gladness
    Idundi is a traditional fermented banana food commonly used by women in North¬eastern Tanzania, believed to aid the healing of the womb of new mothers soon after parturition. However, there is no any published information concerning this food, hence microorganisms involved are not known. A study aimed at genetic characterization of fungi associated with Idundi using DNA techniques was carried out. Fungi were isolated from Idundi samples collected from Same, Soni, and Lushoto. A total of 14 yeasts and 13 molds were isolated. Randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) and PCR of ITS1-5.8S-ITS2 region revealed high genetic diversity of yeasts among and between the geographical locations. PCR of ITS1-5.8S- ITS2 region and PCR-restriction fragments length polymorphism (RFLP) indicated that Rhizopus isolates from the three locations studied were genetically affiliated. PCR targeting genes of the aflatoxigenic pathway indicated that none of the mold could produce aflatoxin. Sequence analysis of the D1/D2 domain of large subunit 26SrDNA of two yeast strains, Y1 and Y5, identified strain Y1 as Candida pavalidae. Strain Y5 could not be assigned to any known genus of yeasts and thus was suggested to be a new yeast species. Phylogenetic inference confirmed that yeast strain Y1 belong to a member of Candida while strain Y5 did not form a clade with either strain Y1 or any other yeast reported elsewhere whose 26SrDNA sequences were used for comparison. From the results, it appears that varieties of fungi are associated with Idundi. Also, the absence of aflatoxigenic molds predicts its safety on the basis of aflatoxin contaminations.
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    Regeneration, diversity and RNA interference strategies to enhance resistance to cassava mosaic viruses in Tanzanian manihot esc ulenta
    (University of Dar es Salaam, 2014) Elibariki, Gladness
    Cassava (Manihot esculenta) is a source of carbohydrate to more than 700 million people in the tropics and a second staple food in Tanzania. However, Cassava production in Tanzania is threatened by viruses, cassava mosaic viruses (CMV) being among the most economically important. The objectives of this study were to develop intervention strategies to control CMV through evaluation of regeneration potential and genetic diversity of Tanzanian farmer preferred cassava landraces (TFPCL) and development of RNAi constructs. Twenty one TFPCL collected from major cassava growing zones of Tanzania and used in this study were able to induce callus, 62 % being able to induce somatic embryos, 8 of them being able to regenerate to plantlets and 5 genotypes rooted on soil. Genetic diversity evaluated using 20 high polymorphic SSR markers grouped the 21 genotypes into three clusters derived from Neighbour joining analysis supported by Principal Coordinate Analysis. An average gene diversity among the genotypes was high (He=0.71) with an average heterozygozity of 0.46 and the total number of alleles across all loci was 127. Furthermore, two double stranded RNA and one antisense constructs carrying important genes for CMV replication and transcriptions were developed. The findings of this study will enhance genetic transformation efforts to combat mosaic viruses affecting cassava in Tanzania.