Browsing by Author "Kivaisi, A. K."

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    Antioxidant Properties of Seven Wild Edible Mushrooms from Tanzania
    (2015-09-30) Hussein, J. M.; Tibuhwa, Donatha D.; Mshandete, A. M.; Kivaisi, A. K.
    Consumption of mushroom has increased remarkably because of their desirable aroma, taste and high nutritional content. Wild edible mushrooms (WEM) are well known for their nutritious and antioxidant properties. This study was conducted to measure and compare the antioxidant activity, total phenolic content (TPC) and total flavonoid content (TFC) of six WEM from selected indigenous Tanzanian forests and one domesticated grown form in methanolic extracts. Results show that among the seven mushroom species extracts, the methanolic extract from Auricularia judae showed the most potent radical scavenging activity of 93.33% while Panus conchatus revealed lowest antioxidant activities of 46.53%. The strongest EC50 was observed in Auricularia judae 0.08 mg/ml while weakest was in P. conchatus >0.3 mg/ml. Nevertheless total phenolics in the methanolic extracts were the highest in P. tenuiculus (431.03±3.63 mg GAE/100 g) and lowest in Macrolepiota procera (136.21±0.98 mgGAE/100 g). Lentinus squarrosulus possessed highest content of β-carotene and flavonoids were 48.15±1.04 mg/100 g and 25.62±1.78 mg/100 g, respectively meanwhile the lowest concentration was found in wild L. sajor-caju 5.35±0.68 mg/100 g and 2.49±1.28 mg/100 g, respectively. Comparatively, domesticated mushroom showed higher scavenging ability of 76.61% than its wild counterparts 62.94%. In conclusion, high antioxidant activity in methanolic extract of WEM due to presence of phenolic content can potentially be used as a source of natural antioxidants.
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    Assessment of Antioxidant Potentials of the Wild and Domesticated Saprophytic Edible Mushrooms from Tanzania
    (2016) Juma, I.; Mshandete, A. M.; Tibuhwa, Donatha D.; Kivaisi, A. K.
    Tanzania natural forests harbor several indigenous edible mushrooms that are meagerly exploited due to various reasons including unawareness on their potential values. This study establishes antioxidant potentials of seven wild edible mushroom species, and their two domesticated forms. The investigation used mushroom methanolic extract for antioxidant activities’ determination. A DPPH (1, 1-diphenyl-2-picrylhydrazyl) radical was used as a substrate to determine radical scavenging abilities whereas ferrozine was employed to determine ferrous ion chelating abilities. Additionally, quantitative analyses for β-carotene, lycopene, flavonoids, and total phenolic compounds were done using spectrophotometric assay. Mushrooms analysed displayed amazing antioxidant potentials which varied between different species and between the wild and domesticated forms of the same species. The range of EC50 values for DPPH free radical scavenging activity (DRSA) was . . mg m , with the strongest and weakest EC50 recorded from P. tenuiculus and the wild Amylosporus sp. IJ-2014, respectively. The range of EC50 values for ferrous ion chelating activity (FICA) was . . mg/mL, with the strongest and weakest EC50 noted in domesticated Amylosporus sp. IJ-2014 and L. sajor-caju, correspondingly. The maximum and minimum total phenolic content (TPC) recorded were 537.39 and 160.97 mg GAE/100g, from domesticated Amylosporus sp. IJ-2014 and Laetiporus sp. IJ-2014, respectively. The highest and least quantities of β-carotene (BC) recorded were 48.59 and 5.56 mg/100g, from P. tenuiculus/wild Amylosporus sp. IJ-2014 and P. cystidiosus, respectively. Lycopene contents (LC) ranged from 2.24 to 18.95 mg/100g, with P. cystidiosus and P. tenuiculus having the slightest and peak values, correspondingly. Maximum value for total flavonoid contents (TFl) recorded was 25.27 mg QE/100g from P. tenuiculus whereas the minimum value was 3.71 mg QE/100g from P. cystidiosus. Due to the antioxidant potentials of these mushrooms, people are advised to maximally exploit them for improved nutrition and health.
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    Molecular Phylogeny of Saprophytic Wild Edible Mushroom Species from Tanzania Based on ITS and nLSU rDNA Sequences
    (2014) Hussein, J. M.; Tibuhwa, Donatha D.; Mshandete, A. M.; Kivaisi, A. K.
    many different saprophytic wild edible mushrooms (SWEM). Few studies have been carried out on characterizing these mushrooms, and those have used conventional methods whereby taxa were characterized using micro- and macromorphological features which are subtle and sometime fail to delimit closely related taxa. In this study, eight SWEM taxa were characterized using two molecular markers—the Internal transcribed spacer (ITS) and the nuclear large subunit (nLSU). The studied sequences were analyzed together with an additional of 19 GenBank sequences of related taxa in the genera Lentinus, Polyporus, Panus, Macrolepiota and Auricularia with maximum likelihood and Aspergillus niger as an outgroup. The BLAST search results on the NCBI database showed that the studied SWEM have ≥ 92% identity for ITS and ≥ 97 % identity for LSU. The phylogenetic tree constructed using the ITS data set revealed two major distinct clades with bootstrap support of 77% and 90% and five sub-clades supporting the five genera. The bootstrap support were 94% for Lentinus, 100% for Polyporus, 98% for Panus, 98% for Macrolepiota and 90 % for Auricularia, while the nLSU data set revealed the same two major distinct clades but with higher bootstrap support of 91% and 100%. The five subclades again supporting the five genera were 100% for Lentinus, 100% for Pluteus, 100% for Panus, 99% for Macrolepiota and 100% for Auricularia. From these results, it is clear that both ITS and LSU delineated the SWEM taxa to the six genera. However, the obtained support values showed that ITS sequences have the highest possibility of successful delineating the studied SWEM to species level than LSU. Moreover, the result also showed the genus Panus forming a monopyletic clade with Lentinus and Polyporus, thus contributing towards a better understanding of its problematic taxonomic ambiguities.
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    Taxonomic Challenges and Distribution of Gracilarioid Algae (Gracilariales, Rhodophyta) in Tanzania
    (2004) Buriyo, Amelia S.; Oliveira, E. C.; Mtolera, M. S. P.; Kivaisi, A. K.
    This paper reviews the taxonomical literature of the gracilarioid algae from Tanzania, and provides information about their ecology and distribution based on an intensive regime of local collection. Its aim was to provide names, even if on a preliminary basis, for local gracilarioid taxa. Our revision shows that species misidentification is widespread and that some species are in need of further critical taxonomic study. Nine species of Gracilaria are reported in the region, including one unidentified Gracilaria or Gracilariopsis.
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    Utility of the Macro-Micromorphological Characteristics Used in Classifying the Species of Termitomyces
    (2010) Tibuhwa, Donatha D.; Kivaisi, A. K.; Magingo, F. S. S.
    Delimitation of Termitomyces species principally rely on the macro-micromorphological characteristics of the species although recently they are supplemented by molecular techniques. Utility of these characters have never been examined to authenticate their usefulness. The present paper therefore, provides a detailed study on the efficacy of the macro and micro-morphological characters used in classifying Termitomyces species. Macromorphologically, capsize was very useful and based on it, three groups were established. Other more useful characters include colour of the cap and pseudorrhiza presence. Annulus presence, pseudorrhiza colour, size, and morphometry were apparently unuseful. Micromorphology was less informative and ambiguously used while untetra basidiospore character was revealed for the first time in this genus. In general macromorphological characteristics provide more reliable taxonomic information to delineate most of the species in the genus than micromophology. However, for the more similar species, an analysis of more stable molecular characters is required. More distinguishing characters are yet to be revealed while ascertaining the used one and taxonomic status of T. citriophylus is essential.