Department of Agricultural Entomology and Apiculture

Permanent URI for this collection


Recent Submissions

Now showing 1 - 10 of 10
  • Item
    Cyanobacterial Occurrence and Diversity in Seagrass Meadows in Coastal Tanzania
    (2007) Hamisi, Mariam; Lyimo, Thomas J.; Muruke, Masoud S. H.
    We report on the occurrence and diversity of cyanobacteria in intertidal seagrass meadows at Ocean Road and Mjimwema, Dar es Salaam, Tanzania. Nutrients, temperature and salinity were measured as comparative environmental factors. A total of 19 different cyanobacteria taxa were encountered, out of which eight were found exclusively in Mjimwema, four exclusively in Ocean Road and seven were common to both sites. Oscillatoria, Lyngbya and Spirulina were the dominant cyanobacterial genera. Cyanobacterial coverage was higher in Mjimwema (31–100%) than in Ocean Road (0–60%). The levels of nutrients in tidal pool waters at Ocean Road ranged from 0.45–1.03 μmol NO3 -N/l, 0.19–0.27 μmol NO2 -N/l and 0.03–0.09 μmol PO4 -P/l. At Mjimwema the nutrient concentration ranges were 0.14–0.93 μmol NO3 -N/l, 0.20–0.30 μmol NO2 -N/l and 0.01-0.07 μmol PO4 -P/l . The nutrient levels were significantly higher at Ocean Road than at Mjimwema (P = 0.001 for nitrate and P = 0.025 for phosphate). There was no significant difference in nitrite levels between the study sites (P = 0.83). The low cyanobacterial diversity and coverage in Ocean Road is related to the high levels of nutrients and physical disturbance from sewage discharge and the harbour in the area.
  • Item
    Cyanobacteria Composition and Impact of Seasonality on Their In Situ Nitrogen Fixation Rate in a Mangrove Ecosystem Adjacent to Zanzibar Town
    (2004) Kyaruzi, Jasson J.; Kyewalyanga, M. S.; Muruke, Masoud S. H.
    To investigate the input of combined nitrogen by cyanobacteria in mangrove ecosystems and the seasonal fluctuation of this biological process, in situ nitrogen fixation activity was measured in day and night experiments carried out at Maruhubi mangrove ecosystem adjacent to Zanzibar town. Sampling was done for 12 months at two stations: Station I covering sandy sediments and Station II muddy sediments. Associated cyanobacteria genera were identified and environmental variables were measured throughout the study period. A total of 10 genera of cyanobacteria were encountered, two of which were the heterocystous cyanobacteria genera Anabaena and Rivularia and eight the non-heterocystous genera Aphanocapsa, Merismopedia, Lyngbya, Microcoleus, Oscillatoria, Phormidium, Schizothrix and Spirulina. At both stations N2 fixation during the night was significantly higher (P ≤ 0.05) than during the day. The average N2-fixation rates at stations I and II were 1.64 and 1.34 nmole N2/hr/m2 respectively, with no significant differences (P ≤ 0.05) observed between seasons at both stations, or between stations in the rainy season. There was no significant correlation (P ≤ 0.05) between nitrogen fixation and physical-chemical variables, except sediment temperature, which showed a significant direct relationship with N2 fixation rate at Station I only. The results suggest that in the investigated ecosystem cyanobacterial diversity and nitrogen fixation are high; and generally seasonal changes do not have a significant influence on nitrogen fixation. It is therefore concluded that cyanobacterial diversity and nitrogen fixation process may contribute in the promotion of primary productivity in the mangrove ecosystem adjacent to Zanzibar town.
  • Item
    A Rapid PCR‐RFLP Method for Monitoring Genetic Variation among Commercial Mushroom Species*
    (Wiley, 2004) Martin, Presley; Muruke, Masoud S. H.; Hosea, Ken M.; Kivaisi, Amelia K.; Zerwas, Nick; Bauerle, Cynthia
    We report the development of a simplified procedure for restriction fragment length polymorphism (RFLP) analysis of mushrooms. We have adapted standard molecular techniques to be amenable to an undergraduate laboratory setting in order to allow students to explore basic questions about fungal diversity and relatedness among mushroom species. The streamlined protocols allowed students to practice important molecular techniques within the context of self-designed investigative projects. This laboratory experience provided opportunities for students to practice strategies for examining molecular diversity among species.
  • Item
    Rapid Purification of Uricase from Bacillus Fastidiosus
    (1996) Muruke, Masoud S. H.; den Camp, Huub J. M. O.; van der Drift, Chris
    A simple, rapid procedure was developed for the purification of uricase from Bacillus fastidiosus. The enzyme was purified to homogeneity in a two-step procedure with the aid of fast-flow column chromatography. In this way high yields (37 %) of pure uricase with a specific activity of 78.3 U/mg were obtained in a short time.
  • Item
    The Level of Enzymes Involved In the Allantoin Metabolism of Bacillus Fastidiosus Grown under Different Conditions
    (Springer Link, 1995) Muruke, Masoud S. H.; den Camp, Huub J. M. O.; Semesi, Amelia K.; van der Drift, Chris
    Bacillus fastidiosus was cultivated in batch and continuous culture on various carbon and nitrogen sources. The enzymes involved in allantoin degradation (allantoinase, urease, carboligase) of B. fastidiosus were hardly affected by either carbon or nitrogen source. In contrast, the enzymes involved in glycerol utilization (glycerol kinase, glycerol 3-phosphate dehydrogenase) were induced during growth on glycerol, but were not affected by the amount of allantoin present.
  • Item
    Novel Nitrogen Sources for Growth of Bacillus Fastidiosus and their Effect on the Activity of NADP-Dependent Glutamate Dehydrogenase
    (1993) Muruke, Masoud S. H.; den Camp, Huub J. M. O.; van der Drift, Chris
    Although Bacillus fastidiosus assimilates ammonium formed internally during growth on urate, allantoin or allantoate via NADP-dependent glutamate dehydrogenase (NADP-GDH), growth on exogenous ammonium as nitrogen source has not been observed. Growth on ammonium, urea and ureidoglycolate, intermediates of the urate degradative pathway, was found to occur if the mineral growth medium containing glycerol as a carbon source was supplemented with both allantoin (0.5 mM) and brain heart infusion (BHI, 0.1%, w/v) or yeast extract. Neither allantoin nor BHI supported growth alone or in combination unless ammonium was present. NADP-GDH activity appeared to be regulated only by the extracellular concentration of allantoin or allantoate. Enzyme activity was not influenced by other nitrogen sources or the intracellular ammonium concentration.
  • Item
    Selenium Accumulating Leafy Vegetables Are a Potential Source of Functional Foods
    (Hindawi Publishing Cooperation, 2015) Mabeyo, Petro E.; Manoko, Mkabwa L.K.; Gruhonjic, Amra; Fitzpatrick, Paul A.; Landberg, Göran; Erdélyi, Máté; Nyandoro, Stephen S.
    Selenium deficiency in humans has been associated with various diseases, the risks of which can be reduced through dietary supplementation. Selenium accumulating plants may provide a beneficial nutrient for avoiding such illnesses. Thus, leafy vegetables such as Amaranthus hybridus, Amaranthus sp., Cucurbita maxima, Ipomoea batatas, Solanum villosum, Solanum scabrum, and Vigna unguiculata were explored for their capabilities to accumulate selenium when grown on selenium enriched soil and for use as a potential source of selenium enriched functional foods. Their selenium contents were determined by spectrophotometry using the complex of 3,3󸀠-diaminobenzidine hydrochloride (DABH) as a chromogen. The mean concentrations in the leaves were found to range from 7.90 ± 0.40 to 1.95 ± 0.12 𝜇g/g dry weight (DW), with C. maxima accumulating the most selenium. In stems, the accumulated selenium content ranged from 1.12 ± 0.10 𝜇g/g in Amaranthus sp. to 5.35 ± 0.78 𝜇g/g DW in C. maxima and was hence significantly different (𝑃 < 0.01). The cancer cell line MDA-MB-231 was used in cytotoxicity assays to determine the anticancer potential of these extracts. With exception of S. scabrum and S. villosum, no cytotoxicity was detected for the selenium enriched vegetable extracts up to 100 𝜇g/mL concentration. Hence, following careful evaluation the studied vegetables may be considered as selenium enriched functional foods.
  • Item
    Assessment of Quality of Tanzanian Honey based on Physicochemical Properties
    (, 2014) Muruke, Masoud H.
    Quality of Tanzanian honey based on physicochemical parameters namely water content, sugar content, pH, ash content, hydroxymethyl furfural (HMF) and honey colour was studied using 26 honey samples collected from ten popular honey producing regions. Analyses were carried out in triplicates using standard methods. Data was analysed using averages, correlation and ANOVA tests. Majority of the honeybees’ honey samples were light coloured while all stingless bees honey samples were dark coloured. Dark coloured honeys contained more minerals; mainly iron, copper and manganese which make them especially fit for medicinal purposes. pH values ranged from 2.61±0.12 to 4.37±0.08, stingless bees honey samples were more acidic than honeybees’ honey samples. Total sugar content values (64.16-84.84 g/100g) were all above the minimum requirement of the national and international standards of not less than 60g/100g. HMF values ranged from 5.0 – 26.4 mg/kg honey, an indication of good quality, being far below the maximum limit allowed by national and international standards of 40mg/kg or 80mg/kg for honeys from the tropics. Of the 26 honey samples studied, all 5 honey samples from stingless bees and 3 from honeybees had moisture content levels above 21%, the maximum limit allowed by national and international standards.. With the exception of two samples from stingless bees, all honeybees honey samples met the minimum requirements of national and international quality standards of maximum allowable ash content of 0.6 %. ANOVA results showed significant differences in the studied physicochemical parameters between groups of honey samples, namely processed honey raw honey and stingless bees’ honey at P<0.05. Pearson correlation analysis showed strong correlation coefficients at P<0.05 between some parameters studied. In conclusion honey colour and moisture content are two important physicochemical parameters that may be used to assess quality of honey.
  • Item
    Assessment of Antioxidant Properties of Honeys from Tanzania
    (, 2014) Muruke, Masoud H.
    In this study, levels and properties of antioxidants, antiradical and iron chelating activities of honeybee and stingless bee honeys were determined using standard methods. The relationship between honey colour and the studied antioxidants was also explored. Phenolic content of stingless bees honey samples (mean value 847.6 mgGAE/100g) was significantly higher (P<0.0001) than that of raw (412.6 mgGAE/100g) and processed (218.4 mgGAE/100g) honeybee honey samples, respectively. Mean value of flavonoid content was 84.96 mgRE/100g for stingless bee honeys, 44.82 mgRE/100g for processed honeybee honeys and 41.60 mgRE/100g for raw honeybee honeys. β-Carotene and lycopene content varied among the three honey categories studied. Honey from stingless bees exhibited higher levels of the two antioxidants than honey bee honeys. Vitamin C content ranged from 20.4 – 66.7 mg/100g in processed honey, 42.5 – 61.6 mg/100g in raw honeybees honey and from 56.2 – 67.6 mg/100g in stingless bee honeys. The number of antiradical activity units in 1 mg of honey (EAU515) varied significantly between the honey categories (P<0.0001). The mean values were 5.21 mg/100g for processed honeybee honeys, 6.8 mg/100g for raw honeybee honeys and 10.6 mg/100g for stingless bee honeys. DPPH radical scavenging and iron chelating activities were highest (lowest EC50) in stingless bee honeys compared to honeybee honeys. EC50 mean value for DPPH was lowest (4.19 mg/ml) in stingless bee honeys, 12.93 mg/ml for raw honeybees honey and 18.03 for processed honeybees’ honey. Similarly, iron chelating activity was highest in stingless bee honeys (EC50 0.04 mg/ml) followed by raw honeybee honeys (EC50 0.057 mg/ml) and processes honeybee honeys (EC50 0.158). A diversity of honey colours ranging from light coloured to dark honeys was recorded in the samples studied. Majority of honeybee honey colours were described as white and light amber, while all the stingless bee honeys were between light amber and amber colours. There were strong positive correlations among the antioxidants studied (r ≥ 0.5 at P<0.01). Honey colour intensity was found to correlate positively with all antioxidants studied. Consistently darker honeys were found to contain higher levels of antioxidants than lighter honeys. In overall, Tanzanian honeys studied contains high levels of antioxidants, depicting good quality characteristics for use as food and as medicine.
  • Item
    Trace Element Concentrations in Soil, Sediments, and Waters in the Vicinity of Geita Gold Mines and North Mara Gold Mines in Northwest Tanzania
    (Taylor & Francis, 2012) Åsgeir, Ålmås R.; Manoko, Mkabwa L.K.
    The “Geita Gold Mine” (GGM) and “North Mara Gold Mines” (NMGM) have devel- oped large quarries in the middle of fertile agricultural lands. Possible hazardous impact on the natural recourse has warranted a study on the trace element concentrations in soils, sediments, and natural waters. Generally, the study shows a great variation in type of elements and intensity of their spill to soils, sediments, and waters. We found indications of acid mine drainage (AMD) of trace metals near the GGM waste rock tailings, but the data are inconclusive. The environmental impact at NMGM was, on the other hand, more extensive. Severe trace element contamination of sediments and waters near one of the mining facilities managed by NMGM is connected to an accidental acid spill in 2009. However, we found strong indication that, in addition to the accident, leakage of alkaline wastewater into surface soils and free water took place from a large wastewater reservoir. We found very high concentrations, especially of As in sediments and water samples downside this reservoir. Water from several sites contained As con- centration in the free water at more than one order of magnitude higher than the WHO drinking water recommendations. The chemical speciation of water samples indicated high fraction of Free Ion Activity (FIA) in several samples and the change in pH had a significant impact on the FIA. Due to extensive alkaline and acidic runoff from these sites, more information about hydrological transport routes and the chemical speciation of the free water is of great importance for assessing potential risk of these mines.