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- ItemOpen AccessAn Adaptive Radial Basis Function Neural Network Glowworm Swarm Optimization for Time-Series Forecasting(2017-11) Isimeto, R.OIt is well noted that statistical approaches to forecasting of time series have been going on since the start of the twentieth century. Advances in the field of computing, motivated researchers to develop new models based on Machine Learning. The Artificial Neural Network models (ANN) are known to construct good and useful approximations for sequence dependencies variables. The past three decades have witnessed active research using a class of ANN, the Radial Basis Function Neural Networks, to forecast time series.Many techniques for forecasting time series using Radial Basis Function Neural Networks (RBFNN) have been proposed and developed in literature. The major challenges in RBFNN lie in the optimization of its full parameters: the number and location of cluster centres, the number of neurons in the hidden layer as well as the output weights. To address these challenges, this study adapted the Clustering Analysis based on Glowworm Swarm Optimization (CGSO) algorithm to obtain a modified Clustering Analysis based on Glowworm Swarm Optimization (CGSOm) algorithm for solving the clustering problem. Adaptation was achieved by incorporating a mechanism that determines the sensor range of the CGSO efficiently and automatically, modifying the initialization method, and introducing a function that measures the cluster error during the iteration phase. For the weight optimization, the Bioluminescence Swarm Optimization algorithm (BSO) was adopted, making it the first time it will be applied in training the weights of the RBFNN. Algorithm as well as software development, and graphical simulation in this work are implemented using functional programming paradigm. The algorithms implemented include the CGSO, CGSOm, BSO, Conjugate Gradient Descent (CGD), Gradient Descent (GD) and Particle Swarm Optimization algorithm (PSO). Using seven well known datasets in literature, the first set of results compared the effectiveness of the CGSOm with the following five well-known clustering algorithms: CGSO, K-means, average linking agglomerative Hierarchical Clustering (HC), Further First (FF), and Learning Vector Quantization(LVQ). Experimental results indicate that the CGSOm gave best entropy and purity values in four out of the seven datasets clustered (57%); CGSO gave best results in two datasets (28.5%); and HC gave best result in one dataset (14.5%). With respect to the weight training, stock price and currencexchange rate data were used to train the combinations of models developed (based on Kmeans, CGSO, CGSOm and GD, CGD, PSO, BSO). The results obtained from the training showed that the CGSOm-CGD RBFNN gave best forecasting accuracy by yielding lowest error values; followed by the CGSOm-BSO RBFNN that gave relatively similar error. Hence, two new training methodologies for time series forecasting resulted from this study; they are the CGSOm-BSO RBFNN and the CGSOm-CGD RBFNN. Validation of the proposed approaches was done in comparison with other RBFNN models: Auto Regressive-Radial Basis Function tuned using Genetic Algorithm and Evolving Radial Basis Function Neural Network, using same data. The results obtained showed that CGSOm-BSO RBFNN and the CGSOm-CGD RBFNN yielded lowest error values.
- ItemOpen AccessAeropalynology and Allergenicity of Pollen in Selected Locations Within Lagos Metropolis, Nigeria(2017-12) Adeniyi, T.AAirborne pollen grains and fern spores (aeroflora) are some of the major causative agents of allergies. However, data gathering on composition and distribution of these aeroflora across Nigeria is incipient. The aim of this study is to monitor the aeroflora in Lagos metropolis and determine the allergenicity of dominant aeroflora. To achieve this, aerosampling was done in Surulere, Ebute-Metta, University of Lagos, Akoka (UNILAG), Bariga and Gbagada. Aerosamples were collected and analysed monthly from January, 2013 to December, 2014. Aeroflora were identified and data obtained was correlated with weather parameters and allergy cases. Dominant aeroflora were freshly collected and their proteins were extracted and subjected to allergenicity tests. A total of 5174 pollen grains and 323 fern spores were collected in all the selected locations in 2013 while 4769 pollen grains and 488 fern spores were collected in the same locations in 2014. Dominant pollen grains recorded were those of Alchornea cordifolia, family Amaranthaceae, Casuarina equisetifolia, family Cyperaceae, family Poaceae, and Terminalia catappa. Pollen and spores counts (PSC) in Surulere, Ebute-Metta and Bariga showed significant negative correlation with relative humidity (p ≤ 0.05). PSC in UNILAG and Gbagada showed significant positive correlation with wheezing cough (p ≤ 0.05). Allergenicity tests revealed a total of 14 allergenic proteins, whereby 12 were newly identified. Results showed that individuals were most susceptible to the 58 kDa allergenic protein of Alchornea cordifolia pollen (84 %; 42 individuals). In conclusion, the general public can now be informed and educated on occurrence and frequency of aeroflora in the studied areas which will assist allergy sufferers in managing allergies. Furthermore, allergenic proteins identified can be used to develop immunotherapy drugs and aid allergy diagnosis, and treatment in Nigeria.
- ItemOpen AccessAllelopathic Potentials of Extracts of Tithonia Diversifolia (Hemsley) A. Gray in Biological C ontrol of Weeds in Cowpea Cropping System(2017-01) Ajayi, O.AThe limitations of physical, mechanical and chemical methods of weed control coupled with the global concern about the risks associated with the use of synthetic herbicides in controlling weeds in agroecosystems has necessitated concerted efforts on promoting alternatives to synthetic herbicides. The aim of this research was to carry out field appraisal of the allelopathic potentials of aqueous extracts of Tithonia diversifolia (Hemsley) A. Gray in biological control of weeds in cowpea [Vigna unguiculata (L.) Walp.] cropping system in order to improve on the measures that have been adopted in biological control of weeds in agroecosystem. The allelochemical constituents of aqueous extracts of T. diversifolia were determined by spectrophotometric method while the phenolic compounds were identified and quantified using High Performance Liquid Chromatography (HPLC). The experiments were laid out in a randomized complete block design (RCBD) with plot size of 3 m x 3 m and three replicates. Aqueous extracts from the root, stem and leaf of T. diversifolia (10.0%, 7.5% and 5.0% w/v) concentrations were applied at 2, 21 and 35 days after planting (DAP) at the rate of 20 l/ha in the two field trials at the experimental farm located at Owode, Ede, Osun State, Nigeria. For comparison, glyphosate herbicide, hand weeding, sorghum-based bioherbicide (Sorghum bicolor L. extract) and weedy plots were maintained as the checks (controls). The allelopathic effects of aqueous extracts from the different parts of Tithonia on germination of seeds and seedling growth of cowpea were investigated by collecting data on germination and seedling growth parameters of two accessions (IT 84E-124 and Ife Brown) at seven DAP and four weeks after planting. The weed suppressive effects of aqueous extracts from different parts of Tithonia on weeds of cowpea cropping system were assessed from the data collected on weed density at 30 and 65 DAP and weed dry weight at 65 DAP. The allelopathic effects of aqueous extracts from the different parts of Tithonia on cowpea yield were evaluated from the data collected on yield parameters which include plant height at six weeks after planting, pods per plants, seeds per pod, 1000-seeds weight and grain yield. The allelochemicals detected in the aqueous extracts of Tithonia were phenols, flavonoids, tannins, saponins and alkaloids. The metabolites were more concentrated in Tithonia leaf extract than in the stem and root extracts. Results also indicated that aqueous extracts of Tithonia did not have significant stimulatory or inhibitory effect (p = 0.51) on germination of cowpea seeds. However, the seedling growth was significantly (p = 0.01) enhanced. Application of Tithonia leaf extract at 10.0% (w/v) concentration led to significant (p = 0.00) increase in shoot dry weight 44.70% and 38.67%, in the two accessions respectively. The corresponding increase in root dry weight were 62.90% and 52.30%. The reduction in weed density at 65 DAP obtained with the application of Tithonia leaf extract at 10% and 7.5% (w/v) concentrations were 65.49% and 62.05% while the weed control efficiencies (WCE) were 69.92% and 59.26% respectively. In relation to the weedy check (control), maximum cowpea grain yield increases were recorded from the application of Tithonia leaf extract at 10.0% and 7.5% (w/v) concentrations with 66.45% and 65.32% increase respectively. The yield recorded with the application of 10.0% w/v and 7.5% w/v Tithonia leaf extract at 20 l/ha was significantly (p = 0.01) higher than the yield recorded in the handweeded and glyphosate treated plots. This implies that the weeds were controlled effectively beyond the critical period of weed interference in cowpea. Thus, aqueous leaf extract of T. diversifolia is recommended for biological control of weeds in cowpea cropping systems.
- ItemOpen AccessThe Anti-Sickling Properties oF Senna Alata and Senna Podocarpa (Fabaceae) Extracts.(2014) Adebesin, O.ANigeria is home to the largest population of sickle cell anemia (SCA) patients, with more than 150 000 children born annually with the disease. Due to the side effects of some drugs eg. hydroxyurea used in the management of SCA, developing novel drugs from traditional medicinal plants can serve as a means to improve the management of this disease. Therefore the possible role(s) of some medicinal plants in the management of sickle cell anemia were investigated. Aqueous ethanol extract of five medicinal plants, namely, Cajanus cajan (beans and leaves), Smilax kraussiana (leaves), Alchornea cordifolia (leaves), Senna alata (leaves), Senna podocarpa (leaves) and “Jana”, a herbal formulation were screened for their membrane stabilising effects on human erythrocytes containing haemoglobin S (HbS) using the osmotic fragility test. Two plants, S.alata and S.podocarpa, were selected, base on their fragilogram for further studies and their aqueous methanol leaf extracts were evaluated for membrane stabilising and antisickling activities. The antioxidant activities of these selected plants extract were also investigated in aqueous system using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging activity (DRSA) and DNA protection assay, while that of the lipid system was done using thiobarbituric acid reactive substances (TBARS) assay. The toxicity profile of hydromethanolic leaf extract of S.alata and S.podocarpa administered at low (200 mg kg bwt-1), medium (600 mg kg bwt-1) and high (1000 mg kg bwt-1) daily oral doses for 15, 35 and 63 days, to young (6 -8 weeks old) albino rats was investigated. Relative organ weights, haematological indices, serum biochemistry, tissue pathology, erythrocyte membrane protein profile as well as sperm-head morphology were used to assess safety. The extracts were also evaluated for their in vitro cytotoxicity activity against K562 mammalian cell line. Aqueous methanol leaf extract of Senna alata and Senna podocarpa at an optimal concentration of 200 and 800 µg ml-1 respectively significantly (P < 0.05) lowered the mean corpuscular fragility values of HbSS RBC, thus conferring 66.01 % and 17.71 % membrane stabilization respectively, while the antisickling efficiency of S.podocarpa was significantly (P < 0.05) lower than that of S.alata. The DRSA of the hydromethanolic leaf extract of S.podocarpa and S.alata showed a dose-dependent response. Senna podocarpa showed DNA protection activity at all doses tested, while Senna alata showed pro-oxidant activity at 10 µg ml-1 and 1000 µg ml-1. The liver weight expressed as a fraction of brain weight was significantly (P < 0.05) elevated over the control by 200- and 600 mg kg.bwt-1 dose of S.alata and S.podocarpa, while a significant (P < 0.05) increase in testis weight was also noticed in the Senna podocarpa 1000 mg kg-1bwt group. A significant (P < 0.05) elevation of plasma ALT activity was induced by S.podocarpa at 600 mg kg-1bwt after nine weeks exposure. The hematocrit was significantly (P < 0.05) elevated by all tested doses of the two extracts. The growth rate and cell viability of K562 cells were reduced by the extracts. The findings of this study revealed that the leaf extract of S.alata and S.podocarpa increased the PCV values as well as the antioxidant capacity of blood, and also had an inhibitory effect on the basal level of liver lipid peroxidation. The extracts also had cytotoxic effect on K562 cells compared to the herbal preparation Nicosan.
- ItemOpen AccessAntioxidant Enzymes and Histopathological Biomarkers of Exposure to Monocyclic Aromatic Hydrocarbons in Clarias Gariepinus (Catfish) and Eudrilus Eugeniae (Earthworm).(2014) Doherty, V.FThe widespread distribution of petroleum products arising from the rapid growth of the petroleum industry in Nigeria has resulted in the pollution of the environment through oil spills involving leakages from tankers, pipelines, tank farms and dumping of waste petroleum products. This study was aimed at identifying histopathological alterations and antioxidants defence systems in Clarias gariepinus (catfish) and Eudrilus eugeniae (earthworm) that can be used as a good battery of biomarkers for early detection of pollution associated with petroleum hydrocarbon and that can be used in monitoring programmes in Nigeria. The impacts and distribution of major toxic components (BTEX - Benzene, Toluene, Ethylbenzene and Xylene) of petroleum products in water and sediment samples collected from sampling stations in the Lagos lagoon and in groundwater and soil around hydrocarbon impacted areas in Ijegun, Lagos, following a pipeline explosion in May 2008 was investigated over a two- year period (February, 2009 – July, 2010). The distribution of benthic communities in the different sampling stations of the Lagos lagoon was assessed. The toxicological evaluations of BTEX were carried out against juvenile stages of C. gariepinus and E. eugeniae. The effect of BTEX on antioxidant enzyme system, lipid peroxidation formation and different organs was investigated in C. gariepinus, Tilapia zillii, Chrysichthys nigrodigitatus and E. eugeniae. The determination of hydrocarbon levels in the samples showed that the levels of Total Hydrocarbon Content (THC) in the water samples around the Atlas cove and Apapa were high with values ranging from 2.03mg/l - 31.38 mg/l and 4.04mg/l - 22.89mg/l, respectively. The highest value of total BTEX in the lagoon sediment was also recorded in the Apapa station (450.53µg/kg) where oil depots and tank farm facilities are located. The study of the macrobenthic community structure showed that the species richness ranged from 1.57 to 2.02 in the reference station, Unilag while in the Atlas Cove, Iddo and Apapa stations, it ranged from 1.80 to 2.89, 1.95 to 3.03 and 1.86 to 2.95 respectively. The highest number of organisms (183) was recorded in the reference stations while the least number (46) was recorded in Apapa. The main hydrocarbon pollution indicator species identified in the impacted aquatic stations were Nais eliguis and Heteromastus filiformis. Results showed elevated THC levels (2.00mg/l–689.12mg/l) in groundwater compared to the World Health Organization maximum permissible value of 0.1 mg/l. Higher values of THC in the soil ranging from 2.16 to 401.41mg/kg were also observed around the impacted area of Ijegun in comparison with 7.03 to 44.61mg/kg observed in the control station. The level of BTEX in the groundwater sampled within the 100m and 150m buffer zones ranged from 1.19 to 4964.33 μg/l compared to the safe limit of 0.2 μg/l set for BTEX compounds in the Environmental Guidelines and Standards for Petroleum Industry in Nigeria (EGASPIN). Toxicological evaluations of the monocyclic aromatic components (BTEX) on Clarias gariepinus showed that ethylbenzene (0.479ml/l) was the most toxic compound tested followed by xylene (0.519ml/l), benzene (0.666ml/l) and toluene (1.190ml/l). Toxicity evaluations against Eudrilus eugeniae showed that xylene (1.212 mg/kg) was the most toxic compound followed by toluene (1.335mg/kg), ethylbenzene (1.366mg/kg) and benzene (1.896mg/kg). The biomarker study revealed an increase in malondialdehyde level and inhibition of the activities of Superoxide dismutase (SOD), Catalase (CAT), Glutathione (GSH) and Glutathione-S-Transferase (GST) in the liver and gills of Clarias gariepinus, Tilapia zillii and Chrysichthys nigrodigitatus, which can serve as good biomarkers for early detection of BTEX and related hydrocarbon pollution. Similar results of consistent increase in MDA levels and inhibition of SOD, CAT, GSH and GST activities in Eudrilus eugeniae exposed to sublethal concentrations of BTEX and petroleum hydrocarbon were observed, therefore confirming the relevance of these antioxidant enzymes as good general biomarkers of hydrocarbon related stress. The histological study identified necrosis and deformation of the gills, inflammations in the liver, wrinkling of the oocyte membrane in the gonads of fish, and endothelial degeneration in earthworms as good histopathological biomarkers of hydrocarbon related stressors. The levels of hydrocarbon observed in the aquatic and terrestrial environment showed that there is widespread contamination as a result of petroleum product importation, storage and distribution. The combination of chemical analysis with these identified biomarkers will therefore provide important tools for early detection, diagnosis and management of hydrocarbon pollution.
- ItemOpen AccessApplication of Liquid Filters to Photothermal / Photoquantum Solar Energy Conversion(University of Lagos, 1986) Chendo, C.A.MThis thesis discusses the development, design, fabrication and testing of spectrally selective beamspliting absorption filters (AF-SSBS) which can decouple quantum and thermal convertors to improve conversion of the total solar spectrum to useful energy. These components separate the solar spectrum into regions or windows matched to the spectral response of the specific photoquantum process and the balance used for photothermal convertor. Higher conversion efficiencies can then be maintained in the photoquantum covertor while the other photons are directed to a thermally decoupled loop at an elevated temperature. Various AF-SSBS developed for hybrid photoquantum/photothermal systems employing silicon cells as the PQ convertors are discussed in terms of their applicability, flexibility and performance. By changing the filter medium concentration (for inorganic salts), optical path length and appropriate glass channel a variety of spectrally selective filters can be tailored to match system performance. Both simplified and detailed performance analyses using moderately concentrated solar radiation showed enhanced overall performance. Preliminary studies have had the following results: (1) 1. The AF-SSBS permits maximum possible PQ conversion efficiency while at the same time permitting high temperature thermal collection. This concept allows the optical quantum receiver to operate at the low temperatures with the greatest efficiency. (2) 2. Realistic performance evaluation requires the knowledge of the spectral distributions of the irradiance source at the time of measurement. There is also the need to spectrally characterize both the solar cell and the irradiance concentrating device. (3) 3. Parametric and design studies suggest that for good PQ/PT performance spectralirradiance measurements must be made at various geographical locations over extended periods. Such data will contribute to models that match PQ materials to different spectral profiles to maximize device performance. (4) 4. Knowledge of heat transfer mechanisms between the various AF-SSBS and PV cells/modules and the determination of optimum flow rates are necessary for optimization of the system performance. (5) Changes in the demand for electrical and thermal energy at design conditions can be met by varying the type of absorption filter, concentration, and photoquantum convertor. The result of the analysis suggests that cobalt sulfate in an appropriate glass channel could be ideal for low-temperature applications (< 1000C) while the heat transfer and related fluids in appropriate cells could serve as medium-temperature applications ( < 2000C) where high thermal energy output is required.
- ItemOpen AccessThe Artisanal Fishing Gears, Crafts Technology and thier Efficiency in the Lekki Lagoon, Nigeria(2009-04) Babatunde, E.EFull texts attached
- ItemOpen AccessAspects of the Biology of Apis Mellifera Adansonii (1758) (Hymenoptera: Apidae: Apoidea) with Emphasis on Honey and Beeswax Production.(School of Postgraduate Studies University of Lagos., 2008) Fasasi, K.A
- ItemOpen AccessAn Attribute-Value Pair (AVP) Model for Creating and Exploiting Annotations in Economic Intelligence.(2014) Okunoye, O.BThis study is concerned with the design and development of an annotation model that gives users the power of expressivity as required in Economic Intelligence (EI) context. Most of the existing annotation platforms lack this power of expressivity. The study also discovered a need to develop an annotation model for creating and structuring annotations that will adequately capture the intention of the users (EI actors) in decision making process. In addition, there was a need for a technique that will allow actors to search for information based on the objective of the search. This study introduced an annotation model called Attribute-Value Pair (AVP) for creating and storing annotations. The study developed a mechanism for exploiting stored annotations based on the context of problem, and used the AVP model to develop a search algorithm that allowed actors to search for information based on the objective of the search. The study used Resource Description Framework (RDF) for the formalism of AVP annotation model. The exploitation phase was implemented using Explore, Query, Analyze and Annotate(EQuA2Te) architecture. A pattern-based algorithm called AVP search was developed that allowed actors to search for information based on the semantic of search objective. The study developed a prototype called Annotation Model and Tools for Economic Intelligence Actors (AMTEA) that used the AVP annotation model for creating, storing and exploiting annotations as well as performing search operations. Two search problems were used as scenarios to evaluate AMTEA system. Results obtained were compared with annotations made on the same set of documents by human agents. The performance evaluation shows that the new AMTEA system detected over 98% of manually made annotations by the human agents. In addition, AMTEA system was able to find new annotations that appear to be relevant. In essence, AMTEA assists human agents to discover new information that might be relevant in decision making process.
- ItemOpen AccessAuto-Antibodies and Immunological Correlates as Indicators of Infertility in some Euthyroid Nigerian Women.(School of Postgraduate Studies University of Lagos., 2008) Oladimeji, S.O
- ItemOpen AccessBacterial Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) in Polluted Estuarine Sediments of the Lagos Lagoon, Nigeria(2017-02) Obi, C.Apotential effects of these pollutants on estuaries. In this study, sediment samples were collected from three sites namely; Apapa, Ofin and Eledu in the Lagos Lagoon. Levels of polycyclic aromatic hydrocarbons (PAHs) and heavy metal contamination of these sites were quantified using GC-FID and flame ionization atomic absorption spectrophotometry respectively. Continual aerobic enrichment procedure with pyrene, fluoranthene, fluorene, benz(a)anthracene supplied as the sole carbon was used in the isolation of bacterial strains that were able to utilize mixed PAHs. The degradation abilities of the isolates and the detection of metabolic intermediates were determined using HPLC HP 5890 series and GC-MS (HP 6890 series) respectively. The isolates were identified by the amplification and sequencing of their 16S rRNA gene. Microbial community structures of the sites were investigated using Illumina sequencing technique. Amplification of the polycyclic aromatic ring hydroxylating dioxygenase (PAHRHD) gene catalyzing the initial hydroxylation of the aromatic ring during PAHs biodegradation was carried out using NidA-forward/NidA-reverse and FRT6A/FRT4B. Protein expression pattern of the isolates in the presence of PAHs was determined using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Results from the determination of physico-chemical parameters showed that Apapa sampling point had the highest level of total PAHs and heavy metal contamination (5.6 μg/kg, 71.90 mg/kg) followed by Ofin (3947 μg/kg, 67 mg/kg) and Eledu (2991 μg/kg, 54.62mg/kg) respectively. Selective aerobic enrichment procedure with pyrene, benz(a)anthracene, fluorene, fluoranthene as sole sources of carbon and energy yielded 12 bacterial isolates. Two strains exhibiting broad spectrum PAH utilization with production of metabolic intermediates were selected for further studies. These were identified as Pseudomonas aeruginosa strain F4b and Rhodococcus sp. strain FF2 with GenBank accession numbers KT894767 and KT894768 respectively. Strain F4b tolerated up to 6.0 mM of copper while strain FF2 was able to tolerate only 3.0 mM of copper. Both strains showed resistance to ampicillin (25 μg), Erythromycin (10 μg), penicillin (10 μg) and cloxacillin (5 μg). The biodegradation studies carried out with strains FF2 and F4b showed rapid exponential increase in cell numbers on some PAHs with average of 86% substrate utilization. Both strains produced metabolic intermediates including benz(a)anthracene 7, 12 dione, 9H Fluorene-9-one and 2,5 dihydroxybenzoic acid among others from benz(a)anthracene, fluorene and pyrene respectively during their growth. Microbial community structure of the sediment samples generated across all libraries a total of 565 bacterial operational taxonomic units (OTUs) (97 % of sequence reads) and 17 archaeal OTUs (3 % of sequence reads). Both the Shannon’s diversity (species richness) and Chao1 (species evenness) indices showed that the Ofin sediment had the highest diversity (9.04) followed by Apapa (5.2) and Eledu (3.99). Samples were dominated by a single OTU assigned to the family Helicobacteraceae (Epsilonproteobacteria). All Illumina sequences from the community studies have been deposited in the NCBI Sequence Read Archive under accession number SRP069095. Protein expression pattern in the presence of different PAHs using SDS-PAGE revealed that these PAHs induced some of the enzymes with molecular weight of 37 kDa that are involved directly or indirectly in the breakdown of these compounds. PAH-RHD genes amplified from both isolates were NarAa and NahAC genes for strain FF2 and F4b respectively. Degradation of the PAH mixtures during microcosm studies resulted in the removal of 40-80% of the total PAHs by indigenous microflora. Illumina sequencing of the 16S rRNA gene sequences generated across all libraries from the microcosm studies generated a total of 75,000 gene sequences which were clustered into 1229 OTUs (at the 97 % identity level). Proteobacteria was identified as the predominant phylum for all samples. PAH-RHD gene (Nid A type) from Mycobacterium sp. HH2 appeared to be the dominant gene followed by (2Fe-2S)-binding protein of Burkholderia sp. Ch1-1 and Rieske (2Fe-2S) protein from Marinobacterium sp. AK27 (Ndo type). This xxiii study has provided the evidence for the existence of an active aerobic autochthonous microbialcommunity in the coastal areas of the Lagos Lagoon with PAH metabolic functionalities.
- ItemOpen AccessBacterial Diversity Studies and probiotic Functions of Bacillus Species in Fermented Locust Bean Seeds (Parkia Biglobosa Jacq. Benth)(2016-01) Adewumi, G.AFermented vegetable protein cotyledons processed into condiments are widely consumed in many West African countries. Production of these condiments involves microbial and biochemical changes during fermentation. The process is natural, uncontrolled and results into product batch variations, safety challenges, and low shelf-life. In this study, multiphasic approaches that combined culture-independent molecular biology techniques, phenotypic microbial characterization and identification, and culture-dependent genomic fingerprints were applied to understand the bacterial diversity and functional dynamics of iru, a traditional alkaline fermented food condiment made from Parkia biglobosa (Jacq. Benth) cotyledons. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) gel profiles based on V3 variable region of amplified 16S rRNA gene, revealed similarities and variations in bacterial community structure in 16 iru samples obtained from different geographical regions in Nigeria, as determined by Dice similarity coefficient and Non-metric Multidimensional Scaling (nMDS). This also grouped the iru samples into distinct clusters, indicating that their bacterial composition is far more diverse and complex than earlier reported. DNA sequences of PCR-DGGE bands identified Bacillus subtilis as the predominant bacterial species in iru. Other bands identified were closest relatives of potential food-borne pathogens and contaminants such as Staphylococcus vitulinus, S. saprophyticus, B. thuringiensis, Morganella morganii, Tetragenococcus halophilus, Salinicoccus jeotgali, Ureibacillus thermosphaericus, Brevibacillus parabrevis, Brevibacterium sp. and uncultured bacteria clones. An average population density of 106 was enumerated in the various iru samples cultured, and mean pH of 7.2. Cultured bacterial colonies ca. 280 phenotyped were Gram-positive rods, catalase-positive, aerobic and facultative anaerobic endospore-formers, and tentatively identified as Bacillus species and its closest relatives. Amplified ribosomal DNA restriction analysis (ARDRA) genomic sub-typing of wild strains comparatively with typed and referenced strains differentiated Bacillus species into B. subtilis and B. cereus phylotypes. Combined profiles of ARDRA, internal transcribed spacer (ITS) PCR, ITS-PCR-restriction fragment length polymorphism (ITS-PCR-RFLP) and randomly amplified polymorphic DNA (RAPD-PCR) showed dominance and diversity of B. subtilis strains in iru. Phylogenetic analysis of the 16S rRNA gene established genetic divergence, evolutionary and clonal relationships among Bacillus strains isolated from Africa and similar Asian fermented condiments. Also, multi locus sequence analysis (MLSA) based on PCR amplification of gyrB, glpF and gmk housekeeping genes and sequences showed phylogenetic relatedness of common ancestral origin between B. cereus and B. thuringiensis, confirming B. cereus as the major member of the B. cereus group associated with iru. Divergent B. subtilis strains from iru, B. subtilis U170B and B. subtilis U146A, including a reference B. clausii UBB-07 (MTCC 5472) were studied for probiotic functions. Vegetative cells of bacilli analysed, generally showed resistance to acidic conditions of pH 2.0 and high tolerance to 0.3% (w/v) bile salts concentration. The two B. subtilis strains fairly inhibited food-borne pathogens, while B. clausii UBB-07 showed stronger inhibitory spectrum. Bacterial cell surface properties comparatively were highest for B. subtilis U146A, B. subtilis U170B and B. clausii UBB-07 in decreasing order. Although, B. clausii UBB-07 adhered more to both undifferentiated and differentiated HT-29 cell lines, the three Bacillus strains effectively interfered and hindered adhesion of Salmonella enterica serovar Typhimurium MBU 1047 to HT-29 cell monolayers. This study comprehensively defined molecular bacterial ecology of iru, as well as established occurrence and dominance of bacilli in this important naturally fermented food condiment in W. Africa. Diverse autochthonous B. subtilis strains and B. cereus were found, a prequisite for prediction of functions and safety. Bacilli in iru demonstrated beneficial probiotic functions. Strains such as these could be used as probiotic starter cultures in small- and large-scale industrial production of condiments to enhance human health.
- ItemOpen AccessBinomics, Culture Trial and DNA Barcoding of Caridean Species from Three Lagoons, South-West Nigeria(2015-12) Akinwunmi, M.FMacrobrachium species are crustaceans found in most inland water and low brackish areas and are of economic importance and possible recruitment into aquaculture. The binomics, culture trial and DNA barcoding of caridean species Brackish water prawn (Macrobrachium macrobrachion) and African River prawn (Macrobrachium vollenhovenii) from Badagry, Lagos and Epe Lagoons, Nigeria were carried out between June 2013 and May 2015. The physico-chemical parameters of the study sites (N 6º 29′ 24.9856″ latitude, E 2º 45′ 52.5347″ longitude – Badagry Lagoon, N 6º 31′ 31.7846″ latitude, E 3º 48′ 23.9768″ longitude – Lagos Lagoon, N 6º 34′ 26.0″ latitude, E 3º 58′ 35.3″ longitude – Epe Lagoon) were measured in-situ. M. macrobrachion and M. vollenhovenii collected for 24 months were analyzed to determine their morphometric characteristics. M. vollenhovenii was reared in triplicate glass tanks with different Crude Protein (CP) levels of purified feed (25%, 30%, 35%, 40% and 45%) and 40% local diet as a control. Molecular technique (DNA barcoding) was used to identify Macrobrachium species found in the study areas. The DNA of the species was extracted using the phenol-chloroform protocol and Norgen tissue kit. Amplification and sequencing of M. macrobrachion and M. vollenhovenii were carried out and further identification of the species was done by comparing with sequenced data in the Genbank. The water temperature for the three lagoons ranged between 21.00 and 32.30 ºC; Dissolved Oxygen ranged from 1.50 to 14.00 mg/L; pH ranged between 5.00 and 9.39; salinity values ranged from 0.00 to 25.00 ‰; water transparency ranged between 17.78 and 175.00 cm and the conductivity ranged between 65.40 and 39600.00 µS/cm. Out of the 4729 specimens collected during the study period, 1770 specimens were from Badagry Lagoon, 924 from Lagos Lagoon and 2035 from Epe Lagoon. The total length (total weight) of M. macrobrachion from the three lagoons ranged from 4.8 cm to 12.8 cm (1.1 – 40.1 g), while M. vollenhovenii ranged from 4.3 cm to 22.6 cm (1.1 – 140.0 g). The condition factor (K) for the combined sexes of M. macrobrachion ranged from 0.3 – 1.4, 0.3 – 1.4 and 0.3 – 1.9 while M. vollenhovenii ranged from 0.4 - 2.7, 0.4 – 3.1 and 0.1 – 2.1 for Badagry, Lagos and Epe Lagoons respectively. The edible parts of M. macrobrachion constituted 44.93 % - 92.04 % of the body weight while that of M. vollenhovenii constituted 40.32 % - 89.80 % in the three lagoons. The stomach contents of M. macrobrachion and M. vollenhovenii from the three lagoons were made up of Bacillariophyta, Chlorophyta, Cyanophyta, Bivalves, Crustaceans, Copepods and detrital materials. The results of the food and feeding habit showed that M. macrobrachion and M. vollenhovenii had preference for detritus. The sex ratio (male: female) for M. macrobrachion and M. vollenhovenii were 1:1.03 and 1:0.21 respectively from Badagry Lagoon, 1:2.60 and 1:1.65 from Lagos Lagoon and 1:0.67 and 1:0.3 from Epe Lagoon. There were significant difference (P < 0.05) in the sex ratio recorded in the three lagoons except for M. macrobrachion from Badagry Lagoon, which showed no significant difference (P > 0.05). At the end of the culture trial, the tank that received 40% CP, compounded from local ingredients performed significantly (P < 0.05) better than the other treatments in terms of average Weight Gain (1.18g), Specific Growth Rate (0.61 %/day), Food Conversion Ratio (5.50), Protein Efficiency Ratio (0.60), Food Efficiency Ratio (0.21) and the survival rate (70.83%). New species of M. asperulum and M. nipponense were observed in Badagry and Epe Lagoons respectively. This study established the occurrence and distribution of M. macrobrachion and M. vollenhovenii from three interconnecting lagoons with the culture potentials of M. vollenhovenii in the laboratory. The phenol-chloroform protocol gave better gel-images than the Norgen tissue kit. The DNA barcode identified that some other species of Macrobrachium were present in Badagry and Epe Lagoons.
- ItemOpen AccessThe Bio-Ecology and Culture Potentials of the Grey Mullet, Mugil Cephalus (Linnaeus) from the Lagos Lagoon, Nigeria(2010-05) Soyinka, O.OThe seasonal abundance, age and growth pattern, food and feeding habits, reproductive biology and culture potentials of the grey mullet, Mugil cephalus (Linnaeus) from the Lagos Lagoon were investigated. The physico-chemical parameters of the lagoon were also monitored. The air temperature ranged from 23.5 to 320C (mean: 27.9 ± 2.100C), while the surface water temperature ranged between 24.5 and 30.80C (mean: 27.9 ± 2.200C). The salinity ranged from 0.0 to 23.5‰ (mean: 9.8 ± 9.13‰), while the hydrogen-ion concentration (pH) ranged between 6.8 and 7.8. The dissolved oxygen ranged from 3.8 to 9.5 mg/l (mean: 5.5 ± 1.65mg/l). The size of the 2661 specimens of M. cephalus used for this study ranged from 1.7 – 29.5cm standard length (total length: 1.9 to 39.0cm) and 0.02 to 450.00g weight. The relative abundance of the species varied, with larger size M. cephalus being more available during the dry season (December – May) and smaller size ones or juveniles predominant in the rainy season (June – November). Growth markings on the scale and otolith of the species did not show discernable marks for determining age. Length-frequency method indicated five age groups representing ages 0 – 1yr (1 - 3cm), 1 – 2yrs (4 - 6cm), 2 – 3yrs (7 - 9cm), 3 – 4yrs (10 - 23cm) and >4yrs (24cm standard length and above). The growth pattern of M cephalus showed a positive allometric growth for both sexes and immature specimens. High correlation (r) values ranging from 0.9003 to 0.9784 obtained was a strong indication of an increase in standard length of the species with a corresponding increase in body weight. The mean monthly condition factor (K) values ranged from 1.39 to 2.30. The species was an omnivore, feeding on algae (blue–green, green, diatoms and desmids), plant materials, annelids, crustaceans, bivalves, fishes and detritus. Sand grains were also found in the stomachs of the fish. The sex ratio for M. cephalus was 1:0.53 and this showed a statistically significant (p<0.05) difference from the expected 1:1 ratio. The fecundity estimates varied from 635,568 – 1,520,185 eggs with a mean fecundity of 832,270 ± 156,016 eggs. The diameter of the eggs varied from 0.36mm to 0.46mm (mean = 0.41 ± 0.04mm). The maturation stages of the testes and ovaries were classified as immature (Stage 1), developing (Stage II), ripening (Stage III), ripe (Stage IV) and spent (Stage V). The immature fish occurred most in the lagoon (75.6%). However, the males were significantly (p<0.05) more abundant than the females. Five major developmental stages of male gonads were observed: spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids and spermatozoa; while six major developmental stages of oocytes were observed: oogonium, primary oocytes, secondary oocytes, vitellogenic oocytes, post-vitellogenic oocytes and hydrated oocytes. In the feeding trial experiment using formulated coppens feed and varied percentage substitutions with low-cost feedstuffs (dried water hyacinth and poultry waste), the highest gain in weight of 125.81% was recorded in the 40% water hyacinth substitution diet. This suggested that water hyacinth incorporation in M. cephalus feed will produce better yield and reduce the cost of fish production. The salinity tolerance experiments showed that the fish tolerated a salinity range of 5‰ to 25‰. The highest survival of 40% was recorded at salinities 10‰ and 15‰. Statistical analysis of the mortality with ANOVA showed no significant (p>0.05) variation. The heavy metals: Cd, Zn, Pb, Ni, Fe and Mn analysed were present in the samples of fish flesh, egg, water and sediment. In the rainy season, the concentrations of heavy metals in the fish were Cd (0.03ppm); Mn (0.074ppm); Pb (0.482ppm); Zn (0.78ppm); Fe (1.332ppm) and Ni (-0.085ppm). The heavy metals concentrations in the fish in the dry season were Cd (-0.059 to -0.027ppm); Mn (- 0.145 to -0.066ppm); Pb (0.234 to 0.298); Zn (1.089 to 2.349ppm); Fe (1.433 to 1.729ppm) and Ni (-0.293 to -0.201ppm). The level of heavy metals in the fish tissues in this study was below the FAO / WHO standard of safety for human consumption. In conclusion, the existence of M. cephalus in large numbers in the Lagos Lagoon, its high fecundity, wide range of food spectra of both plant and animal origin and heavy metals contamination below the FAO/WHO recommended safety standards for human consumption are indicative of a favourable environment of the lagoon to support a viable brackish-water fishery of the species. In addition, desirable baseline information needed for a sustainable brackish-water cum marine culture of the species and a reduction in cost of fish feed by employing unconventional but available and efficient feedstuff in M. cephalus culture are provided in this study.
- ItemOpen AccessBioactivity of Extracts of some Nigerian Plants on Insect Pests of Stored Grains.(School of Postgraduate Studies University of Lagos., 2008) Abiodun, A.D
- ItemOpen AccessBiochemical responses of sprague dawley rats and new zealand rabbits following long-term dietary exposure to heavy metal contaminated fish(School of Postgraduate Studies University of Lagos, 2015) Bolawa, O.E.The environment is man’s surroundings, which include all the circumstances, influences and events that he encounters in his life time. The natural environment encompasses all living and non living things occurring naturally on earth (Dale, 2007). Without health, development and a protected environment, health has little value. Development can only be achieved through the contributions of healthy people. Continued population growth, irrational use of resources, and increasing generation of wastes create unsustainable demands on the environment (Oldroyd, 2006). Sound management of the environment brings major health benefits while inadequate or no management results in large adverse effects on health and sustainable interaction between people and their environment. There are limits to the extent to which the soil and fresh water resources can be exploited and ecosystems are used as a receptacle for the wastes generated by human society (Adams and Lambert, 2006). There are also global limits to the exploitation of non-renewable resources and to the capacity of the planetary system to absorb wastes. These global limits have become apparent as in the depletion of stratospheric ozone layer, which has implications for health and agricultural production and in the possibility of climatic disruption as a result of the release of greenhouse gases (Adams and Lambert, 2006). In developing countries, growth in industrial production has been accompanied by an increased incidence of environmental related diseases and physical hazards (Adams and David, 2006). Many of the workforces suffer exposure to occupational hazards. Priority given to human health raises an ethical dilemma if “Health for all” conflicts with protecting the environment. Respect for nature and the control of environmental degradation is a 2nd order principle which must be observed lest it conflicts with the 1st order principle of meeting and ensuring human survival needs (Seaton et al., 2005). The report of the World Council on environment and development defined sustainable development as development meeting the needs of all the present population without compromising the ability of future generation to meet their own needs. This could prove contradictory if meeting present needs implies the irreversible depletion of natural resources and the degradation of ecosystem. But the intelligent application of what is known, combined with caution and a continuous commitment to improving understanding of links between the environment, development and health can change these trends. Focusing on health provides many insights into how a better balance can be achieved between the environment and development (Dale, 2007).
- ItemOpen AccessBiochemical Studies of Secondary Metabolite of Penicillium Chrysogenum Grown on Selected Agro-wastes.(2012) Onyegeme-Okerenta, B.MSelected agro-wastes found in Lagos, Nigeria (cassava peels, corncob, sawdust, and sugarcane pulp) were compared with glucose and lactose as microbial substrates for cultivating P. chrysogenum (wild strain). This study was designed to give added value to agro waste as substrates to cultivate P. chrysogenum and subsequent production of secondary metabolite with antibiotic and anticoagulant properties. In the growth studies, corn cob and cassava peels significantly (p < 0.05) produced the highest amount of mycelia weight. Corn cob yielded a mycelia weight of 0.15 ± 0.02 and 0.92 ± 0.04mg/ml on the third and ninth day respectively while cassava peels yielded a mycelia weight of 0.13 ± 0.07 and 0.12 ± 0.02mg/ml on the third and twelfth day respectively. Mycelia weight of the organism, in media containing glucose, sugar cane and lactose was 0.12 ± 0.02, 0.068 ± 0.05 and 0.055 ± 0.03mg/ml respectively, was highest on the ninth day. Sawdust gave the least growth with a mycelia weight of 0.07 ± 0.01mg/ml on the third day. Cassava media has the highest carbohydrate content. Changes in extracellular protein secreted into the different media (every 3days for 21days) shows that culture media containing cassava peels gave the highest protein peak of 0.38 ± 0.08 mg/ml on the sixth day, while corncob gave an early peak of 0.30 ± 0.03mg/ml on the third day. Sawdust gave two protein peaks, 0.15 ± 0.03 on the third day and 0.25 ± 0.01mg/ml on the twelfth day. A total protein yield of 0.2 ± 0.05, 0.08 ± 0.02, 0.06 ± 0.02 mg/ml respectively was obtained with glucose, sugarcane pulp and lactose containing media on the third day. The results suggest that cassava peels, corncob and sugarcane pulp could serve as cheap fermentation substrates for the growth of the fungus. Optimum pH and temperature of growth and antibiotic production was 6.5 and 25OC respectively. UV xxix modification of parent strain produced two mutant strains with 70% increase in penicillin production. In vitro antibacterial activity of the culture extracts was tested against some clinical bacterial isolates, namely, B. subtilis, E. coli, P. mirabilis and P. aeruginosa. Commercial Benzyl Penicillin was used as reference drug. The culture extracts and standard drug inhibited the growth of B. subtilis and E. coli. Zone of inhibition varied with the carbon source. Culture extracts and reference drug were not effective against the isolates of P. aeruginosa and P. mirabilis because they produce β-lactamase enzymes which hydrolyse the β-lactam present in the extract and reference drug. Antibacterial activity of extracts from cultures containing cassava peels and sugarcane pulp compared positively with that of the standard drug. The Minimum inhibitory concentration (MIC) of the reference drug against the susceptible organisms was 0.2 - 0.4mg/ml. For the culture extracts, the MIC ranged from 0.4 to 2.0mg/ml. It was 0.4 - 0.8mg/ml for cassava peels and sugarcane pulp, 0.6 - 0.8mg/ml for glucose and lactose, 0.8 - 1.0mg/ml for corncob and 1.0 - 2.0mg/ml for sawdust. Toxicity study showed that the extract is safe for use as there were no visible changes or recorded deaths 48 - 72hours after administration of the extracts. Haematological evaluation showed a significant decrease (p<0.05) in platelet count for both the extract and reference drug in the sub acute toxicity study as well as in infection and inflammatory conditions. The extract was shown to have a potent antithrombic and anticoagulant activities against thrombin and whole blood respectively. Higher concentrations of the extract and reference drug caused an increase in whole blood clotting time. At 6mg/ml of the extract and 5mg/ml of the reference drug, clot formation was not observed. There was complete inhibition of thrombin coagulation at concentrations above 10 and 20mg/ml of the reference drug and extract respectively.
- ItemOpen AccessBiocontrol Efficacy of a New Strain of Myrothecium Roridum on Eichhornia Crassipes (Water Hyacinth) in Lagos State Nigeria.(School of Postgraduate Studies University of Lagos., 2008) Okunowo, W.O
- ItemOpen AccessBioethanol (Bio-Fuel) Production from Agro-Waste using Yeast Isolates from Nigeria(2012-11) Ebabhi, A.MBio-fuels are fuels derived from biological materials or their by-products such as agricultural waste. A study was carried out to assess the production of bio-fuel (bioethanol) from some hydrolyzed agricultural wastes using yeast species isolated from Cola acuminata, Ipomoea batatas, Manihot esculenta, Pennisetum glaucum, Sorghum bicolor, Solanum tuberosum, Zea mays and palmwine (from Elaeis guineensis). Eight yeast species including Candida krusei, Candida tropicalis strain A, Candida tropicalis strain B, Kluyveromyces marxianus, Pichia caribbica, Saccharomyces cerevisiae strain A, Saccharomyces cerevisiae strain B and Schizosaccharomyces pombe were used. The agro-wastes and starchy substrates were pretreated through milling, saccharification with mineral acid (H2SO4/HCl) and Anacardium occidentale (cashew) Nut Shell Extract (CNSE). Substrates were distilled after 72 h of fermentation. The quantity of bioethanol produced varied with substrates and organisms used. The analysis of the CNSE revealed the presence of hydrolytic enzymes such as endoglucanase, exoglucanase and xylanase in varying concentrations. Biochemical analysis and DNA sequencing revealed that some of the fungal species are probably new strains. Using 100 g hydrolyzed substrates, the highest amount (33.34 ± 2.81 g/L) of bioethanol was obtained from sweet potato tuber hydrolyzed with 50 ml of 50% HCl and fermented with S. pombe. Plantain peel hydrolyzed with CNSE and fermented with S. pombe produced 28.12±1.61 g/L of bioethanol. The quantity of reducing sugar in the agro-waste hydrolyzed with CNSE was maximum of 491 mg/g in sugarcane chaff and minimum of 46 mg/g in rice husk. Sugar fermentation test of the yeasts showed that they can ferment sugars such as glucose, lactose, maltose, fructose and xylose. Lactose and xylose were fermented atypically by S. cerevisiae strain B. All strains tested were resistant to 30 µg/l of chloramphenicol and they were able to grow at 37°C except Candida krusei. In the urease hydrolysis test, S. pombe, P. caribbica and S. cerevisiae strain B were positive. Growth study of the yeast strains on eight broth media showed that potato dextrose broth, malt peptone broth and millet dextrose broth are the best media for growth and reproduction. This is probably the first report of isolation and characterization of fermenting yeast from maize, kolanut and sweet potato in Nigeria. Gas chromatographic (GC) assay of the CNSE hydrolysates showed the presence of simple sugars in varying concentrations with cassava peel possessing the highest concentration of glucose (38.19 mg/L) while plantain peel yielded the lowest concentratiom of 5.44 mg/L. The GC analysis of some of the agro-waste distillates showed considerable concentrations of bioethanol. Highest concentration of 2.41 x 104 mg/L was obtained from sweet potato peel fermented with S. cerevisiae strain A whereas the lowest concentration of 2.75x103 was obtained from plantain peel fermented with S. pombe. The cashew nutshell extract was able to biodegrade the agro-wastes due to the synergy of the cellulases that are present in it. This study showed that agro-waste which are diverse and commonly pose significant disposal problems can be used for the production of bio-fuel and other organic compounds. Fossil fuel causes environmental pollution and replacing it with bio-fuel like bioethanol from agro-waste will be more environmental friendly and will also reduce pressure on crop plants.
- ItemOpen AccessBiological Control of Ceretocystis Paradoxa Dade C.Moreau causing Black Rot of the oil Palm (ELAEIS GUINEENSIS JACQ) Sprouted Seeds using Trichoderma spp(School of Postgraduate Studies University of Lagos., 2008) Eziashi, E.I