Fish and fisheries of Bakolori Reservoir

Details are given of fisheries activities carried out in Bakolori Reservoir within the context of many and varied functions of Sokoto Rima River Basin Development Authority. Experimental fishing was conducted for 55 days in 1979 when the reservoir was only one year old and the exercise continued in 1980 and 1981 also for 85 and 52 days respectively. During the exercise, the catch per unit effort showed an increasing trend with increasing efforts by four times to that of the initial. The fish harvest was 1.205 kg/day when 3.8 nets were operated in 1979, this went up to 3.2 kg when the number of nets were increased to 8.37/day in 1980. This increasing trend continued in 1981 season also when 16.15 nets caught 5.756 kg fish per day. A direct relationship was observed in the fishing efforts and catch. Tilapia, Clarias, Labeo, Schilbe and Synodontis spp, were the most predominant fish species in the catch and contributed more than 97% of the total fish harvest

An evaluation of the trophic status of the Shen Reservoir by an analysis of phytoplankton composition and water characteristics

In an effort to evaluate the production potential of an artificial impoundment, the phytoplankton of the Shen reservoir was sampled from November 1981 to June 1982 at three stations during three periods of distinct seasonal hydrographic characteristics. The samples were subsampled and quantified. Most of the phytoplankton were identified to the species level. There were in all 53 species comprising Chlorophyceae contributing 36.70% with species of Volvox, Pediastrum, Closterium, Staurodesmus and Ankistrodesmus as dominant species in this group. The Cyanophyceae contributed 30.00% with species of Microcystis, Nostoc , and Oscillatoria as the dominant species. An analysis of temporal and spatial changes in composition and abundance of the various groups showed that these were influenced by water temperature, sampling period and station. Based on the trophic status of the most abundant species, the composition of the phytoplankton is indicative of a tropical reservoir with a moderate productivity for fish culture

The distribution and feeding habits of a cichlid fish Oreochromis niloticus (Linnaeus) in Opa Reservoir, Ile-Ife

The distribution of Oreochromis niloticus was studied in Opa reservoir (Nigeria) using a graded set of gillnets while the food and feeding habits were studied using a castnet to collect the fish samples. About 90% of the fish specimens were caught near the reservoir bottom while about 69% of the specimens were caught within the inshore area of the reservoir. The species fed mainly on detritus, algae and higher plants. Feeding rhythm in O. niloticus started around 6.00 a.m. and reached a peak by 3.00 p.m. but then declined gradually until 6.00 p.m. These results can be utilized for the proper management of the fish species in the reservoir

Indication of pollution in a teaching and research farm reservoir

The production and productivity of a water body is largely dependent on its quality. One major source of water pollution is from the agrochemicals from nearby farmlands. The quality of water in the Obafemi Awolowo University Teaching and Research Farm Reservoir (Ile-Ife, Nigeria) was monitored between October, 1993 and March, 1994. Structured questionnaires were administered to obtain information on the types of agrochemicals in use on the farm. Water samples were collected fortnightly for analyses of the physico-chemical parameters and ionic content of the water. Investigation revealed that 21 agrochemicals had been in use on the farm. The physico-chemical parameters of the water showed that the water was very poor in nutrient. The high concentration of ammonium ion contents of the water shows an indication that the residues of certain agrochemicals got into the water to pollute it. Agrochemicals should be used with great caution on farmlands especially in areas close to water bodies from which man obtains fish and other proteinous foods. This paper also suggests a regular monitoring of water quality of reservoirs in order to pick the earliest signs of pollution

Numerical Study On Transient Flow In The Deep Naturally Fractured Reservoir With High Pressure

According to the experimental results and the characteristics of the pressure-sensitive fractured formation, a transient flow model is developed for the deep naturally-fractured reservoirs with different outer boundary conditions. The finite element equations for the model are derived. After generating the unstructured grids in the solution regions, the finite element method is used to calculate the pressure type curves for the pressure-sensitive fractured reservoir with different outer boundaries, such as the infinite boundary, circle boundary and combined linear boundaries, and the characteristics of the type curves are comparatively analyzed. The effects on the pressure curves caused by pressure sensitivity module and the effective radius combined parameter are determined, and the method for calculating the pressure-sensitive reservoir parameters is introduced. By analyzing the real field case in the high temperature and pressure reservoir, the perfect results show that the transient flow model for the pressure-sensitive fractured reservoir in this paper is correct.

The Experimental and Numerical Studies on Gas Production from Hydrate Reservoir by Depressurization

A set of experimental system to study hydrate dissociation in porous media is built and some experiments on hydrate dissociation by depressurization are carried out. A mathematical model is developed to simulate the hydrate dissociation by depressurization in hydrate-bearing porous media. The model can be used to analyze the effects of the flow of multiphase fluids, the kinetic process and endothermic process of hydrate dissociation, ice-water phase equilibrium, the variation of permeability, convection and conduction on the hydrate dissociation, and gas and water productions. The numerical results agree well with the experimental results, which validate our mathematical model. For a 3-D hydrate reservoir of Class 3, the evolutions of pressure, temperature, and saturations are elucidated and the effects of some main parameters on gas and water rates are analyzed. Numerical results show that gas can be produced effectively from hydrate reservoir in the first stage of depressurization. Then, methods such as thermal stimulation or inhibitor injection should be considered due to the energy deficiency of formation energy. The numerical results for 3-D hydrate reservoir of Class 1 show that the overlying gas hydrate zone can apparently enhance gas rate and prolong life span of gas reservoir.

An appraisal of the current status of the fisheries of Eleiyele Reservoir by its fisheries cooperatives

In a study undertaken to evaluate the status of the fisheries of Eleiyele Reservoir (Nigeria) between 1995 and 1997, thermal stratification was observed to breakdown between December and March. Of the physico-chemical variables, transparency was positively correlated (p<0.05) with primary productivity, conductivity and dissolved oxygen concentration. Primary productivity ranged between 0.38mgC/m super(2)/d and 3.OmgC/ m super(2)/d, being lowest in April. BOD values ranged between 1.3mg-2.2mgO/l indicative of clean unpolluted water. Nine fish species belonging to the families Cichlidae, Centropomidae and Mochokidae were identified. Cichlids were the most abundant with Hemichromis species being predominant. Fishing was only carried out in the reservoir during the dry season months of November to April. Fish landing data for the reservoir, obtained from the Fisheries Division of the Ministry of Agriculture and Natural resources, Oyo State, in conjunction with comparative data from the Cooperative fishermen was low. It demonstrated a decreasing trend from January to April and during the period between 1985 and 1996, when compared with data collected in 1985 and 1986 from a previous similar study. Reasons for the low fish yield from the reservoir are discussed and compared with other Nigerian reservoirs

Ruwan Kanya reservoir in Kano State as a model small scale sport fishing ground

The paper examined the Ruwan Kanya Reservoir in Kano State. It gave a background information on the fisheries of the lake. Also discussed is tilapia transplantation from Jakara to Ruwan Kanya reservoir. The transplantation revealed a tremendous improvement on the Lake fisheries species now recorded include Lates niloticus, Tilapia, Hydrocynus, Gnathonemus, Mormyrops mabpterurus and others. The proximity of the Ruwan Kanya Reservoir to Tiga Lake and the tourism resort near it, affords the place a good opportunity to serve as a good sport fishing ground. Procedures for transforming the reservoir to sport fishing ground have been advanced

The reproduction of Oreochromis niloticus (Linnaeus) in Opa reservoir, Ile-Ife, Nigeria

Oreochromis niloticus is one of the commercial fish species in Opa reservoir. It bred throughout the period of study in the reservoir. The fish species is a maternal mouth brooder with the female specimens carrying eggs and alevins in their mouths. The sex ratio of O. niloticus was 1:1 and the maximum fecundity recorded was 1810 eggs. The fecundity increased as the fish length increased. The relatively high fecundity of the fish species in the reservoir is an indication of the suitability of the small reservoir in contributing to fish production

Sex-ratio and fecundity of catfish, Clarias gariepinus in Opa reservoir, Obafemi Awolowo University, Ile-Ife

The sex-ratio of Clarias gariepinus in Opa Reservoir was 2:1 (male/female). The fecundity of C. gariepinus in Opa reservoir ranged between 1,567 and 650,625 egg. The fish species had extended spawning period which probably spreads the risk of predation on the eggs. The population of the fish species could be improved by stocking with the female breeders

Structure-function studies of serine hydrolases: synthesis of a gene for ∝-lytic protease and the purification and characterization of a mutant β-lactamase

The author has constructed a synthetic gene for ∝-lytic protease. Since the DNA sequence of the protein is not known, the gene was designed by using the reverse translation of ∝-lytic protease's amino acid sequence. Unique restriction sites are carefully sought in the degenerate DNA sequence to aid in future mutagenesis studies. The unique restriction sites are designed approximately 50 base pairs apart and their appropriate codons used in the DNA sequence. The codons used to construct the DNA sequence of ∝-lytic protease are preferred codons in E-coli or used in the production of β-lactamase. Codon usage is also distributed evenly to ensure that one particular codon is not heavily used. The gene is essentially constructed from the outside in. The gene is built in a stepwise fashion using plasmids as the vehicles for the ∝-lytic oligomers. The use of plasmids allows the replication and isolation of large quantities of the intermediates during gene synthesis. The ∝-lytic DNA is a double-stranded oligomer that has sufficient overhang and sticky ends to anneal correctly in the vector. After six steps of incorporating ∝-lytic DNA, the gene is completed and sequenced to ensure that the correct DNA sequence is present and that no mutations occurred in the structural gene.

β-lactamase is the other serine hydrolase studied in this thesis. The author used the class A RTEM-1 β- lactamase encoded on the plasmid pBR322 to investigate the roll of the conserved threonine residue at position 71. Cassette mutagenesis was previously used to generate all possible amino acid substitutions at position 71. The work presented here describes the purification and kinetic characterization of a T71H mutant previously constructed by S. Schultz. The mutated gene was transferred into plasmid pJN for expression and induced with IPTG. The enzyme is purified by column chromatography and FPLC to homogeneity. Kinetic studies reveal that the mutant has lower k_(cat) values on benzylpenicillin, cephalothin and 6-aminopenicillanic acid but no changes in k_m except for cephalothin which is approximately 4 times higher. The mutant did not change siginificantly in its pH profile compared to the wild-type enzyme. Also, the mutant is more sensitive to thermal denaturation as compared to the wild-type enzyme. However, experimental evidence indicates that the probable generation of a positive charge at position 71 thermally stabilized the mutant.

Single cell proteomics microchip to profile immune function, with applications in stem cell biology, translational disease mechanism study and clinical therapeutics monitoring

In response to infection or tissue dysfunction, immune cells develop into highly heterogeneous repertoires with diverse functions. Capturing the full spectrum of these functions requires analysis of large numbers of effector molecules from single cells. However, currently only 3-5 functional proteins can be measured from single cells. We developed a single cell functional proteomics approach that integrates a microchip platform with multiplex cell purification. This approach can quantitate 20 proteins from >5,000 phenotypically pure single cells simultaneously. With a 1-million fold miniaturization, the system can detect down to ~100 molecules and requires only ~104 cells. Single cell functional proteomic analysis finds broad applications in basic, translational and clinical studies. In the three studies conducted, it yielded critical insights for understanding clinical cancer immunotherapy, inflammatory bowel disease (IBD) mechanism and hematopoietic stem cell (HSC) biology.

To study phenotypically defined cell populations, single cell barcode microchips were coupled with upstream multiplex cell purification based on up to 11 parameters. Statistical algorithms were developed to process and model the high dimensional readouts. This analysis evaluates rare cells and is versatile for various cells and proteins. (1) We conducted an immune monitoring study of a phase 2 cancer cellular immunotherapy clinical trial that used T-cell receptor (TCR) transgenic T cells as major therapeutics to treat metastatic melanoma. We evaluated the functional proteome of 4 antigen-specific, phenotypically defined T cell populations from peripheral blood of 3 patients across 8 time points. (2) Natural killer (NK) cells can play a protective role in chronic inflammation and their surface receptor – killer immunoglobulin-like receptor (KIR) – has been identified as a risk factor of IBD. We compared the functional behavior of NK cells that had differential KIR expressions. These NK cells were retrieved from the blood of 12 patients with different genetic backgrounds. (3) HSCs are the progenitors of immune cells and are thought to have no immediate functional capacity against pathogen. However, recent studies identified expression of Toll-like receptors (TLRs) on HSCs. We studied the functional capacity of HSCs upon TLR activation. The comparison of HSCs from wild-type mice against those from genetics knock-out mouse models elucidates the responding signaling pathway.

In all three cases, we observed profound functional heterogeneity within phenotypically defined cells. Polyfunctional cells that conduct multiple functions also produce those proteins in large amounts. They dominate the immune response. In the cancer immunotherapy, the strong cytotoxic and antitumor functions from transgenic TCR T cells contributed to a ~30% tumor reduction immediately after the therapy. However, this infused immune response disappeared within 2-3 weeks. Later on, some patients gained a second antitumor response, consisted of the emergence of endogenous antitumor cytotoxic T cells and their production of multiple antitumor functions. These patients showed more effective long-term tumor control. In the IBD mechanism study, we noticed that, compared with others, NK cells expressing KIR2DL3 receptor secreted a large array of effector proteins, such as TNF-α, CCLs and CXCLs. The functions from these cells regulated disease-contributing cells and protected host tissues. Their existence correlated with IBD disease susceptibility. In the HSC study, the HSCs exhibited functional capacity by producing TNF-α, IL-6 and GM-CSF. TLR stimulation activated the NF-κB signaling in HSCs. Single cell functional proteome contains rich information that is independent from the genome and transcriptome. In all three cases, functional proteomic evaluation uncovered critical biological insights that would not be resolved otherwise. The integrated single cell functional proteomic analysis constructed a detail kinetic picture of the immune response that took place during the clinical cancer immunotherapy. It revealed concrete functional evidence that connected genetics to IBD disease susceptibility. Further, it provided predictors that correlated with clinical responses and pathogenic outcomes.

Alau reservoir: a multi-dimensional resource base in Borno State

Aspects of the fishery resources of Alau Reservoir in Maiduguri are reported upon in this paper. It focuses attention on the fishery in terms of fish abundance and potential. It also discusses other resources associated with the fish production. Various other possible uses of the reservoir are discussed too. The reservoir is thus revealed to be a most useful and versatile one in terms of fishery resources and fund generation

Function of microRNA-146a and NF-κB in physiologic and pathologic hematopoiesis

During inflammation and infection, hematopoietic stem and progenitor cells (HSPCs) are stimulated to proliferate and differentiate into mature immune cells, especially of the myeloid lineage. MicroRNA-146a (miR-146a) is a critical negative regulator of inflammation. Deletion of the gene encoding miR-146a—expressed in all blood cell types—produces effects that appear as dysregulated inflammatory hematopoiesis, leading to a decline in the number and quality of hematopoietic stem cells (HSCs), excessive myeloproliferation, and, ultimately, to exhaustion of the HSCs and hematopoietic neoplasms. Six-week-old deleted mice are normal, with no effect on cell numbers, but by 4 months bone marrow hypercellularity can be seen, and by 8 months marrow exhaustion is becoming evident. The ability of HSCs to replenish the entire hematopoietic repertoire in a myelo-ablated mouse also declines precipitously as miR-146a-deficient mice age. In the absence of miR-146a, LPS-mediated serial inflammatory stimulation accelerates the effects of aging. This chronic inflammatory stress on HSCs in deleted mice involves a molecular axis consisting of upregulation of the signaling protein TRAF6 leading to excessive activity of the transcription factor NF-κB and overproduction of the cytokine IL-6. At the cellular level, transplant studies show that the defects are attributable to both an intrinsic problem in the miR-146a-deficient HSCs and extrinsic effects of miR-146a-deficient lymphocytes and non-hematopoietic cells. This study has identified a microRNA, miR-146a, to be a critical regulator of HSC homeostasis during chronic inflammatory challenge in mice and has provided a molecular connection between chronic inflammation and the development of bone marrow failure and myeloproliferative neoplasms. This may have implications for human hematopoietic malignancies, such as myelodysplastic syndrome, which frequently displays downregulated miR-146a expression.