Journal of Advances in Biology & Biotechnology

Introduction: The objectives of this work consisted of a phytochemical study of the leaves and pulp of Ziziphus mauritiana Lam collected from the flooded and dried sites of Niono and Sévaré in Mali and to evaluate the biological activities of the extracts, i.e. the antiradical activity and hemolytic activity.

Methods: Phytochemical analysis and biological activities were performed at the plant biochemistry and biotechnology laboratory of the FST / USTTB. The tannins and flavonoids were extracted by maceration, dosed by spectrophotometry then analyzed by HPLC and their antiradical activity was evaluated by the DPPH method. The saponosides were extracted by decoction and their hemolytic activity was evaluated on beef blood.

Results: Tannins and flavonoids were abundant in the leaves and the pulp but saponosides were absent in the pulp.

Calcium ions, carbonate ions and chloride ions were abundant in the leaves and pulp of Zizyphus mauritiana Lam from the dried site of Niono and the flooded site of Sévaré. HPLC chromatograms showed two peaks of gallic acid in the tannins extracts.

Catechical tannins and flavonoids of the flooded sites have a greater antiradical activity than those of the dried sites. However, their antiradical activity remains lower than that of ascorbic acid whose IC50 was measured at 30 μg.

Leaf saponosides from the flooded site of Niono and the dried site of Sévaré showed hemolytic activity on red blood cells of beef.

Conclusion: The leaves and pulps of Zizyphus mauritiana Lam were rich in phenolic compounds and have interesting antiradical activity. The saponosides extracted from the leaves showed hemolytic activity.

Aim: To determine the species composition, relative abundance and status of honey bee pests and diseases in South Ari district of South Omo Zone of Southern Western Ethiopia.

Study Design: Four major honey producing peasant associations (PAs) representing diverse ecological zones were selected purposively, while the sub-localities, villages and beekeepers were selected randomly using a nested design.

Place and Duration of Study: Survey was conducted between 1, August – 30, December 2019 with the interval of one month in major honey producing peasant associations representing diverse ecological zones of Ari district of South Western Ethiopia.

Methodology: The assessment on abundance and status was made from of half kilogram of fresh and dry honey comb samples that were taken from 720 farmer’s hives of four peasant associations using taxonomic key of books related to arthropod pests and diseases of honey bee.

Results: Five species of predators and parasitoids belonging to four orders were recorded. Of these 76.63% accounts for small hive beetles, followed ants (38.31%) and wasps (19.92%). Besides, six type’s diseases of honey bee caused by different pathogens were recorded. Of which, Chalk brood, other virosis, European foulbrood and American foulbrood, respectively were the most frequently occurring. In terms of the status, the diseases of honey bee were in the following orders, i.e., Chalk brood > other virosis > European foulbrood > American foulbrood > Sac Brood Virus, while their pests were in the following orders, i.e., Small hive beetles > Ants > Wasps > Wax moths > Spiders.

Conclusion: Arthropod pests and diseases were the most important constraints of honey colony and honey production in the study areas. Thus, it is important to design and implement effective management strategies to reduce loss of honey colony and honey production in the study area.

Aims: This study aims to define criteria for the main physical and chemical characteristics of the environmental niches populated with electrochemically active microorganisms, capable to perform anaerobic respiration and potentially used in Bio-electrochemical systems such as Microbial Fuel Cells.  

Study Design: In this study, specific parameters of the environment in water bodies (such as lakes, streams etc.) and their bottom layers are analyzed. The main parameters of interest include the concentration of dissolved oxygen in the water column, the organic matter content in the sediments and the presence of alternative electron acceptors (such as iron and manganese ions) to support anaerobic respiration. Sediment microorganisms are characterized for their electrochemical and biodegradation activity.

Place and Duration of Study: The tested sediment and water samples were collected from "Poda" Protected Site located on the outfall of Lake “Uzungeren”, south of City of Burgas, Bulgaria.

Methodology: The samples were analyzed employing TGA, ICP and microbiological methods focusing on chemical, physical and biological conditions available for anaerobic respiration in this ecological niche.

Results: The results show very low concentrations of dissolved oxygen (from 1.4 to 2.2 mg/dm³ in the various locations). The conductivity and the pH values ​​measured were relatively high and the mean values obtained are 5230 μS/cm and 8.2 respectively. The sediment samples demonstrated very high organic matter content (22.5% of the dry mass) and relatively high levels of iron and manganese.

Microbial fuel cell powered by mixed bacterial culture isolated from the tested sediment samples demonstrated stable performance reaching power density of 3.5 W/m² and the COD removal rate of 42 mgO₂/dm³ per day.

Conclusion: The result confirms the initial hypothesis that electrochemically active microorganisms are available in environments with high concentration of organic matter, iron and manganese in combination with low availability of dissolved oxygen. Mixed culture of anaerobic bacteria isolated from the tested sediment sample was successfully implemented to power Microbial Fuel Cell.

Aims: This study was designed to evaluate the effects of Efavirenz-based highly active antiretroviral therapy (EFV_b-HAART, Efavirenz/Lamivudine/Tenofovir) with emphasis on survival, longevity, climbing ability, and reproductive capacity in D. melanogaster.

Methods: The experiments were carried out at the Africa Center of Excellence in Phytomedicine Research and Development (ACEPRD), University of Jos, Nigeria between January 2017 and August 2018. D. melanogaster (both sexes) 1-4 days old were exposed to different concentrations of EFV_b-HAART (range 10-1200 mg) in the fly food for initial 7 days to determine the LD₅₀, then 5 day fly exposure to 93.11 mg, 46.56 mg, 23.28 mg or 11.64 mg for negative geotaxis assay, and acetylcholinesterase (AChE) activity. Furthermore, 28-day fly survival and longevity were determined. Statistical significance was presumed at P< 0.05.

Results: The LD₅₀ of EFV_b-HAART in D. melanogaster was 93.11 mg. The HAART exposed flies showed significantly (P<0.001) increased mortality, significant (P<0.001) decreased fly eclosion, acetylcholinesterse (AChE) activity and climbing ability compared to unexposed group at all experimental concentrations.

Conclusion: The decreased 28-day survival, longevity, climbing ability and reproductive capacity at all experimental concentrations may be attributable to the deleterious effects of EFV_b-HAART in D. melanogaster. Our findings suggest that long term use of EFV_b-HAART by HIV patients may be associated with accelerated aging, decreased life expectancy, quality of life (due to possible neurotoxicity) and reproductive competence, as evidenced by increased mortality, reduced longevity, AChE activity, and 100% emergence failure respectively in D. melanogaster, and may require further study in humans. We recommend further research to expound the biochemical and molecular toxicodynamics of EFV_b- HAART in D. melanogaster with the view of ameliorating same.

Background and Objective: Chitin is world’s second most abundant structural carbohydrate in nature and is found as a structural component in the cell wall of fungi and exoskeletons of invertebrates. During senescence, it is degraded by the enzyme, chitinase. In addition, chitinase has been exploited for various commercial applications such as control of insects and fungal pathogens in order to protect the crops, waste management, cosmetics and food industries. Chitinases have been found to be widely distributed in various organisms including viruses, animals, bacteria, fungi, higher plants and insects. In the present study, various soil samples enriched in chitinous waste were screened for the isolation of bacteria capable of producing chitinase.

Methodology: Chitinase producing bacteria were isolated using serial dilution plating technique onto different agar media. Primary and secondary screening were performed and the isolate producing maximum chitinase was selected for biochemical identification and 16s rRNA sequencing. The secretion of extracellular chitinase by this strain was optimized with respect to pH, temperature, incubation time, substrate concentration, carbon and nitrogen sources and inoculum size. All these components were optimized using OFAT (one factor at a time) approach.

Results: A total of 29 bacterial isolates were found exhibiting secretion of extracellular chitinase as determined using zones of clearance. Based on the area of zone of clearance, six isolates were selected for secondary screening and the most potent isolate was identified as Bacillus cereus. The maximum chitinase production by this strain was obtained at 37°C and pH 7.0 after 48 hours of incubation. The maximum chitinase secretion was observed on addition of 1% colloidal chitin and 0.05% yeast extract in the medium.