Resource Productivity and Technical Efficiency of Small Scale Groundnut Farmers in Taraba State, Nigeria

This study which was carried out in Taraba State, Nigeria investigated the resource productivity and technical efficiency of groundnut farmers in the State. Data for the study were obtained using a structured questionnaire administered to a total of 270 small scale groundnut farmers. Farm size, seed, family labour and use of agrochemicals were the factors that affected the technical efficiency of the farmers. In the case of allocative efficiency, farming experience, literacy level and family size were found to be significant. The level of profit made by the farmers was influenced by costs of seed, labour, transport and storage. The average scores for technical, allocative and economic efficiencies were 0.77, 0.70 and 0.54 respectively. The groundnut farmers were, therefore, not economically efficient. Improvement in their efficiency levels requires that attention be given to their costs of operation and their socioeconomic characteristics. Keywords: Productivity, Technical, Allocative, Economic, Efficienc

Sensitivity of Earthworm (Eisenia fetida) in Mining Soil from Ijero-Ekiti, Nigeria

Excavation and processing of mineral deposits are valuable revenue sources yet they contribute serious environmental problems worldwide. Mining activities are widespread and contribute to heavy metal contamination in rural communities in Ekiti State, Nigeria. Available research failed to establish how mining soil may impact on resident terrestrial organisms. This study assessed the health of soil from active mining site by testing it on earthworms (Eisenia fetida) for 10 weeks. Survival, mobility, morphology and behaviour of worms were assessed while soil was analyzed for selected heavy metals by atomic absorption spectrometry. Worm survival was evident as the proportion of reference soil increased in exposure mixture and improved until 92% in the control. Worms curled up at the bottom of test vessels with varying proportions of mining site soil and appeared discolored and dehydrated when taken out of test soil, with characteristic sluggishness, particularly as the proportion of mining soil increased in exposure mixtures. Though metal levels were within permissible limits, morphology of exposed worms were visibly impacted, which corresponds in severity with increasing proportion of mining soil. On the contrary, worms tested in 100% reference soil appeared healthy and active in upper part of exposure vessels. These results suggest that the tested mining soil had adverse impacts on mobility, morphology, behavior and survival of exposed organisms when compared with the control population. Therefore, food products grown downstream of the mining site may be at risk of heavy metal contamination with consequences on food quality, water quality and food chain

How does Trypanosoma equiperdum fit into the Trypanozoon group? A cluster analysis by RAPD and multiplex-endonuclease genotyping approach.

The pathogenic trypanosomes Trypanosoma equiperdum, T. evansi as well as T. brucei are morphologically identical. In horses, these parasites are considered to cause respectively dourine, surra and nagana. Previous molecular attempts to differentiate these species were not successful for T. evansi and T. equiperdum; only T. b. brucei could be differentiated to a certain extent. In this study we analysed 10 T. equiperdum, 8 T. evansi and 4 T. b. brucei using Random Amplified Polymorphic DNA (RAPD) and multiplex-endonuclease fingerprinting, a modified AFLP technique. The results obtained confirm the homogeneity of the T. evansi group tested. The T. b. brucei clustered out in a heterogenous group. For T. equiperdum the situation is more complex: 8 out of 10 T. equiperdum clustered together with the T. evansi group, while 2 T. equiperdum strains were more related to T. b. brucei. Hence, 2 hypotheses can be formulated: (1) only 2 T. equiperdum strains are genuine T. equiperdum causing dourine; all other T. equiperdum strains actually are T. evansi causing surra or (2) T. equiperdum does not exist at all. In that case, the different clinical outcome of horse infections with T. evansi or T. b. brucei is primarily related to the host immune response

Genome analysis and DNA marker-based characterisation of pathogenic trypanosomes.

The advances in genomics technologies and genome analysis methods that offer new leads for accelerating discovery of putative targets for developing overall control tools are reviewed in Chapter 1. In Chapter 2, a PCR typing method based on restriction fragment length polymorphism analysis of the internal transcribed sequence (ITS) rDNA region was used to reveal distinct fingerprinting patterns that characterise human- and animal-derived Trypanosoma brucei gambiense and T. b. brucei isolates. Although these results also highlighted doubts about the uniformity of T. brucei subspecies, the limitation of such a typing technique that is based on a single genetic locus is obvious. As a result, the studies were extended to include all T. brucei subspecies in a more global amplified fragment length polymorphism (AFLP) genotyping (Chapter 3). This approach permitted an unbiased estimate of the total genome variance and revealed closer genetic relatedness between, and higher variability within, T. b. brucei and T. b. rhodesiense subspecies, compared to T. b. gambiense strains. However, it was clear from these studies that a finer-scale genotyping tool with enhanced resolution power was required. Chapter 4 describes such an advanced tool, a multiplex-endonuclease genotyping analysis (MEGA) approach that simultaneously accesses multiple independent restriction enzyme-based polymorphisms within the genome. It offered a robust and detailed genotyping tool and was, therefore, used to study the population genetic structure of T. brucei isolates, for epidemiological and cladistic analysis (Chapter 5). The MEGA approach envisages the application of genotyping to identify genetic profiles that are associated with specific (parasite) traits. Therefore, in Chapter 6, genotypes were constructed and correlated with human serum response traits of T. brucei rhodesiense clones and strains, to further provide a general method for measuring differential phenotypes and an objective assessment of such differences. Also, such fine-scale approach can be used to rapidly enrich for identifiable polymorphisms in a set of known DNA sequences known to be associated with a phenotypic trait of interest. Using sets of four endonucleases selected on the basis of the concept defined by the MEGA approach, the role of differential DNA methylation patterns in the human serum response properties of trypanosomes was evaluated (Chapter 6), which proved to be insignificant. Furthermore, we clarified the genetic relationships between T. equiperdum and other Trypanozoon species (Chapter 7). In Chapter 8, a general discussion of the data is presented. In summary, three main applications of molecular marker systems in trypanosomes were described in this thesis. These involve genomic studies for (1) generating sensitive tools for molecular typing of strains, (2) elucidating taxonomy of Trypanozoon, and (3) the analysis of the relationships between genetic variations and their consequent functional effects that may enhance our understanding of important traits. These applications have permitted fine-scale genotypic characterisation of the parasites, and offered a template for phenotypic correlations of the genotype data

Measure of molecular diversity within the Trypanosoma brucei subspecies Trypanosoma brucei brucei and Trypanosoma brucei gambiense as revealed by genotypic characterization

We have evaluated whether sequence polymorphisms in the rRNA intergenic spacer region can be used to study the relatedness c.' two subspecies of Trypanosoma brucei. Thirteen T. bnrcei isolates made up of 6 T. b. brucei and 7 T. b. gambiense were analyzed using restriction fragment length polymorphism (RFLP). By PCR-based restriction mapping of the ITS I-5.8S-ITS2 ribosomal repeat unit. we found a fingerprint pattern that separately identifies each of the two subspecies analyzed, with unique restriction fragments observed in all but f of the T. b. gambiense "human" isolates. Interestingly, the restriction profile for a virulent group 2 T. b. gambiense human isolate revealed an unusual RFLP pattern different from the profile of other human isolates. Sequencing data from four representatives of each of the two subspecies indicated that the intergenic spacer region had a conserved ITS- l and a variable 5.8S with unique transversions, insertions, or deletions. The ITS-2 regions contained a single repeated element at similar positions in all isolates examined. but not in 2 of the human isolates. A unique 4-by ; C3A} sequence was found within the 5.8S region of human T. b. gambiense isolates. Phylogenetic analysis of the data suggests that their common ancestor was a ronhuman animal pathogen and that human pathogenicity might have evolved secondarily. Our data show that cryptic species within the T. brucei group can be distinguished by differences in the PCR-RFLP profile of the rDNA repeat

Assessment of selected metal levels in Ishiagu Pb-Zn mine district soils and Oryza sativa, southeast, Nigeria

Pollutants have a tendency to sequestrate into remote sites in different environmental matrices thereby reducing the level of available fraction for uptake in living organisms. We examined availability of metals by subjecting soil and rice plant samples from Ishiagu mining district to a sequential extraction procedure and subsequently analyzed the extracts using Atomic Absorption Spectrophotometer (AAS). Our results revealed that metals were moderately available in samples in the following decreasing order: Zn>Pb>As>Cd>Se>Cu. Though metal levels differed in rice plant samples compared to soil, we noted also that availability of these pollutants varied spatially among various study locations. Based on available acceptable range, copper and zinc were within tolerable limits while cadmium was in excess in some study locations. On the other hand, levels of lead in rice plant samples exceeded acceptable limits. Considering the levels reported from different locations, it is possible that metals were immobilized in soil organic matter or trapped in other forms. Though in general metal levels were within acceptable limits in our study locations, we recommend that deliberate steps be taken by authorities to curtail indiscriminate mining activities capable of polluting soils and farm lands. For this reason, farmers should be encouraged to plant safe cultivars since this rice variety is a known poor metal accumulator.Keywords: Heavy Metals, Soil, Rice Plants, Ishiagu, Mining Distric

Trypanosoma brucei genomics and the challenge of identifying drug and vaccine targets

There have been tremendous advances in our knowledge of trypanosome biology, yet many aspects remain unclear. Currently, the genome of Trypanosome brucei is being sequenced and this, with other genome-wide analysis methods, could provide novel insights into the parasite and facilitate the development of effective controls. An important new challenge investigators face is how to exploit the information in studying a parasite with so many genetic peculiarities. Here, we summarize our current understanding of molecular genetics of T. brucei and attempt to link genome analysis to the prospects for identifying possible targets for vaccines, novel drugs and specific diagnostics. The value of newly developed genotyping approaches in accelerating these processes is discussed

Population genetic structure and cladistic analysis of Trypanosoma brucei isolates

Using a novel multilocus DNA marker analysis method, we studied the population genetic structure of Trypansoma brucei stocks and derived clones isolated from animal and rhodesiense sleeping sickness patients during a national sleeping sickness control program in Mukono district, Uganda. We then performed a cladistic analysis to trace relationships and evolution, using stocks and clones recovered from geographically and temporally matched hosts, including inter-strain comparisons with T. b. gambiense stocks and clones. Our results show that while there was close genetic relatedness among parasite populations from the same geographical region, micro-heterogeneities exist between different stocks. Data are presented that indicate that not every human sleeping sickness focus may be associated with a particular human-infective trypanosome strain responsible for long-term stability of the reference focus. We provide evidence of genetic sub-structuring among type 1 T. b. gambiense stocks, which has potentially important implications for molecular epidemiology of T. brucei

Trypanosoma brucei genomics and the challenge of identifying drug and vaccine targets.

There have been tremendous advances in our knowledge of trypanosome biology, yet many aspects remain unclear. Currently, the genome of Trypanosome brucei is being sequenced and this, with other genome-wide analysis methods, could provide novel insights into the parasite and facilitate the development of effective controls. An important new challenge investigators face is how to exploit the information in studying a parasite with so many genetic peculiarities. Here, we summarize our current understanding of molecular genetics of T. brucei and attempt to link genome analysis to the prospects for identifying possible targets for vaccines, novel drugs and specific diagnostics. The value of newly developed genotyping approaches in accelerating these processes is discussed