MST-School of Pure and Applied Sciences

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This collections contains bibliographic information and abstracts of Master theses and dissertation in the School of Pure and Applied Sciences held in Kenyatta University Library

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A Comparative Study of Hepatitis B Virus among In-Mates and Low Risk Voluntary Blood Donors in Garissa County, Kenya
(Kenyatta University, 2024-07) Odallo, Vincent Bahati
Hepatitis B virus (HBV) infection is a life-threatening infection that attacks the liver and can cause both acute and chronic disease. This creates a high risk of death from cirrhosis and liver cancer. Hepatitis B infection poses a major health concern globally. It is estimated that in 2019, about 296 million people had been chronically infected with HBV globally and about 820, 000 deaths from hepatocellular carcinoma and cirrhosis were reported. In Kenya, HBV prevalence stands at chronic states of intermediate range (5-7%) and high (≥8%) with regional variations. Garissa County carries a high HBV infection risk with a reported prevalence of 14.1% in pregnant women attending antenatal care (ANC) clinics. This study sought to determine the seroprevalence and circulating Hepatitis B virus genotypes among the prisoners and compare it with that of the surrounding general population at Garissa Main Prison and Garissa County Referral Hospital respectively in Garissa, Kenya. A total of 130 in-mates and 130 voluntary blood donors were sampled in this study and a questionnaire used to collect data on their socio-demographic characteristics. Blood was then collected in plain vacutainers and the resulting serum tested for Hepatitis B surface antigen (HBsAg) using a rapid test strip. HBV DNA was then extracted from the serum and a 930bp region of the overlapping P/S gene amplified and sequenced. Logistic regression was used to evaluate socio-demographic factors associated with HBV seropositivity. Resulting HBV DNA sequences were manually edited, assembled into contigs and then aligned. Genotype identity of the aligned sequences was initially made using the Geno2pheno [hbv] 2.0 online data base. The aligned sequences from this study and genotype specific sequences in Genbank were then used to infer phylogenetic relationships of the local strains. The Geno2pheno [hbv] 2.0 online data base was further used to identify mutations in the samples associated with diagnostic failure and vaccine failure (in the S gene) and antiviral resistance (in the P gene). Majority of the study participants were males (86.9% among inmates and 95.4% among blood donors. Majority (76.2%) of the in-mates and of the donors (83.1%) were aged between 20-40 years while majority (51.4 % of the donors and 81.5% of in mates) had only a primary school level of education. HBV seroprevalence was significantly higher among in-mates compared to blood donors. Out of the total number of in-mates tested, 7 (5.4%) were HBV seropositive. Conversely, among blood donors 4 (3.1 %) were seropositive. There was a significant association between HBV seropositivity and gender among both the blood donors and in-mates. Out of the 22 HBV-DNA positive samples, genotype D was the most prevalent among both the in-mates and blood donors (81.8%). Genotype A sub-genotype A1 was only detected among the in-mate population (18.2%). All the genotype D sequences were found to be either D/A or D/E recombinants. HBsAg escape mutations associated with diagnostic failure were noted among both study populations. As a pioneer study on HBV in Kenyan prisons, the current study confirms the categorization of in-mates as HBV high risk populations. The dominance of HBV genotype D is a novel finding as studies in other regions of the country have identified genotype A as the most prevalent. Further studies should be carried out in other regions to determine circulating HBV genotypes and HBsAg escape mutations that may influence HBV infection diagnosis and treatment outcome in those regions.
Abundance and Conservation Status of Prunus Africana in Western Mau Forest, Kenya
(Kenyatta University, 2020-03) Chebet, Gladys
Prunus africana (Hook. f) Kalkman, 1965 (formerly Pygeum africanum Hook.f) is a geographically widespread tree restricted to highland forest of main land Africa and outlying islands. The species is commercially important for its bark, which is used in the treatment of prostate gland disorders. It also produces high quality timber used locally for building poles and furniture as well as fuel wood. The high demand for the bark has led to notable destruction of the species in natural forests, leading to concerns on the long term sustainability of harvesting and the conservation of the species. Despite the fact that Mau forest is a protected area, the region experiences illegal exploitation with P. africana being one of the main targets. The tree is of great demand for its strong timber and highly medicinal bark making its population to be under threat. As a result P. africana is listed as vulnerable species under Appendix II of CITES. In this study, information on P. africana was obtained mainly from literature survey while population data was obtained by sampling methods. The study was conducted in Western Mau forest (longitude E35027.05’ to E35039.42’ and latitude 0010’46’’S to 0017’42’’S) which is found in the South Rift region, Kericho county. Transects were laid across four blocks in Western Mau forest and diameter at breast height (dbh) and height of mature trees measured. The level and causes of disturbances were collected using questionaires and through observation and recorded for each of the plots. Saplings were counted and recorded in subplots and seedlings counted in micro plots. Densities of seedlings, saplings and mature P. africana trees were examined across the Western blocks of Mau forest. A socio-economic survey was further conducted to determine community perceptions on the status of the tree under study. The data generated were analyzed using both descriptive and inferential statistics. Data on height and dbh were summarized as mean ± SE and variations tested using one way ANOVA. Socio-economic data were mainly analyzed in form of proportions and variations between sites tested using chi-square statisctics.Data was presented in histograms, tables and graphs. Inferential statistics revealed significant variation in the density of saplings (p<0.05). Majority of the mature trees were of height between 20m and 40m though this height varied significantly between the blocks. As concerns dbh, most of the trees ranged between 40cm and 50cm with a signigficant variation between the blocks. The seedling numbers exceeded saplings and trees, suggesting potential for regeneration and population increase even though the population is not increasing. Observations showed that human activities, herbivory and diseases pose serious threats to P. africana tree. The local community was of the opinion that the main anthropogenic activities affecting the tree are unsustainable de-barking, logging, and animal grazing. It was recommended that awareness creation be organized regularly for all stakeholders on sustainable de-barking and logging be greatly regulated to save this tree of great value to mankind. The local community and more so those who rely on the tree for herbal medicine should be encouraged to grow the tree in their homestead gardens to reduce the pressure on wild trees thereby enhancing its conservation.
Abundance, genetic diversity and symbiotic potential of common bean (phaseolus vulgaris l.) nodule associated bacteria in Western Kenya soils
(Kenyatta University, 2016-07) Simiyu, Wekesa Clabe
Plant growth-promoting rhizobacteria (PGPR) are beneficial native soil bacteria that colonize plant roots and result in increased plant growth. Those that colonise the nodules of legumes are known as nodule associated bacteria (NAB). The aim of this study was to determine the distribution and genetic diversity of NAB that colonize Phaseolus vulgaris, their abundance, and symbiotic efficiency when coinoculated with Phaseolus vulgaris in Western Kenya soils. The soil samples were collected from cultivated lands in Kisumu near Lake Victoria, slopes of Mt. Elgon and Kakamega. In each of these regions, the soil samples were collected from four regions. 1ml of soil solution at 10 fold dilution for seven dilution steps (10-1 to 10-7) and three replications for each dilution was used to inoculate common bean seedling in Leonard jars. They were harvested after four weeks to determine abundance of NAB using most probable number method. Common bean nodules were also collected directly from the farmers’ farms in the above three regions. Harvested nodules and those collected from the field were cleaned and surface sterilized, crushed and exudates streaked on YEM agar growth media. Pure colonies were further cultured in YEM broth at 280C for three days and the genomic DNA isolated from the bacteria using Qiagen DNA extraction kit. 16SrRNA gene was amplified by 27F and 1492R primers and PCR products resolved by agarose gel electrophoresis and sequenced. 16SrRNA gene analysis revealed that NAB that nodulate with common beans are genetically diverse as they formed clusters on the phylogenetic tree and their distribution depends on chemical characteristics of the soil. BLASTn showered that isolated strains belonged to the genus Pseudomonas, Providencia, Rhizobia, Klebsiella, Sphingobacterium, Enterobacter, Delfitia, Acinetobacter and one strain did not have sequence homology at the GenBank. Mt. Elgon region had the highest population of NAB (120000 cells per gram of the soil), followed by Kisumu (1290 cells per gram of the soil) and Kakamega region had the lowest (17 cells per gram of the soil). The effect of PGPR on the yield of common beans was significantly higher (p < 0.001) when co-inoculated with Rhizobia compared to the yield of Rhizobia inoculated alone or control (not inoculated) (p < 0.05). This study therefore provides knowledge on the type of NAB that nodulates with common beans and factors that favour their distribution necessary for production of PGPR inoculants suitable to the soils of Western Kenya.
Accidents as an occupational health problem - a case of Babadogo industrial area Nairobi - Kenya
(2012-02-28) Otieno, Samwel Boaz
An investigation of occupational accidents among factory workers was carried out in Babadogo Industrial Area in carried out in Babadogo Industrial Area in Ruaraka -Nairobi, between September 1998 and December 1998. In this cross sectional study a total of 300 workers were interviewed in 18 factories selected randomly. The data was coded and analyzed by Statistical Programme for Social Scientists (SPSS) (1998) program. It was shown that 93% of the factories in Babadogo Industrial Area were in general consumer and service manufacturing category (P < 0.001) with most of the workers (83.33%) being males (P < 0.001) and only 58.4% having post secondary and primary school training. The investigation also revealed that up to 47.2% of respondents have had occupational accidents in the previous twelve months under study. Of the injured workers 45.4% have only had accidents once while 2.8% have had accidents at least 15 times or more (P < 0.001). At least 38% of the injured workers did not report accidents to their employers. It was also shown that there was a strong association between the causes of accidents and occupations (P < 0.001) with handling objects being responsible for 39.6% of all accidents. Accidents rates were also shown to vary with experience (P < 0.025) with most accidents. (51.2%) occurring in those who have worked for 5 years or less. Within each occupation type accident rates were varied with most accidents affecting machine operators. The differences in accident rates of different occupations was found to be significant (P < 0.001). It is also shown that accidents rates vary with time of the day with peaks at 12.00 noon (18.1%) and at 3.00 p.m. (21.0%), however there was no significant differences, in the rates between morning and afternoons (P > 0.05). The investigation also revealed that accident rates varied with day of the week with most accidents, (24.4%) occurring on Wednesday. The variation was also shown to occur by the month with most accidents (22.5%) occurring in the month of August. Investigation also showed significant variation in several aspects of safety standards (P < 0.001) housekeeping standards (P < 0.001) and presence of several physical and chemical hazards within the work environment, details of which are given in the text. This study revealed that handling objects; hand tools and power driven machinery caused most of accidents. Much attention should therefore be focused towards these causes in order to reduce accidents. If further revealed that machine operators had higher rate of injuries compared to other occupations hence much attention should be given focused on training and improvement of production on machinery in order to reduce accidents. It was also shown that a significant number of workers had low level of education hence attention should be given to training of workers, as this could be a contributing factor in accident causation as most of the workers injured were machine operators hence the employees should be involved in ergonomic design were of machine. Much attention in form of education of workers should be given to particular time of machines. Much attention in form of education of workers should be given to particular time of day (12 noon) and (3.00 p.m.) and to Wednesdays, as most accidents tended to occur during that time. Housekeeping standards, safety standards and chemical and physical hazards level were shown to be the significant factors, hence much attention should also be focused in work environment improvement as this could reduce the number of accidents.
Action of Symmetric Group S5 on The Cosets of Some of Its Non-Maximal Subgroups
(Kenyatta University, 2020-07) Omori, Kerubo Lydiah
The Action of Symmetry Groups of Platonic Solids on their Respective Vertices
(Kenyatta University, 2020) Waweru, R. Brian
Platonic solids are 3-dimensional regular, convex polyhedrons. Each of the faces are equidistant and equiangular to each other in any of the solids. They derive their name from the ancient Greek philosopher, P lato who wrote about them in his dialogue, the Timaeus as reported by Cornford (2014). The solids features have fascinated mathematicians for decades including the renown geometer, Euclid: In his Book XIII of the Elements, as rewrote by Heath et al. (1956), he successfully determined the exact number of solids that qualify to be Platonic Solids; tetrahedron, cube, octahedron, dodecahedron and icosahedron. In group theory, the symmetry group of an object is the group of all transformations under which the object remains unchanged, endowed with the group operation of composition. Due to their inherent symmetry of these solids many mathematicians have attempted to derive their symmetry groups. For instant, Foster (1990) who successfully enumerated the symmetry groups of the dodecahedron and recently Morandi (2004) attempted to compute these symmetric groups of the solids using a computer program called Maple. Although such contributions are noteworthy, a few attempts have been made to explore other features such as the symmetry groups of the platonic solids. Thus, this project investigates the properties of the group action of the symmetry groups of these platonic solids acting on their respective vertices. We embark on constructing the symmetry groups of each of the solids then employ the orbit-stabilizer and other theorems to determine the ranks and sub-degrees of each solid. The action of G on V shows that tetrahedron has a rank of 2, the octahedron has a rank of 3, dodecahedron has a rank of 6 while the cube and icosahedron have a rank of 4.
Adaptation of an enzyme-linked immunosorbent assay for determination of diminazene aceturate in goat serum and tissue residues of animals
(2011-11-08) Karanja, Wycliff Maina
The importance of food safety through the reduction of residues in our food supply cannot be overemphasized. Food safety remains a major challenge confronting contemporary society. Analytical methods are needed to generate the data on which dietary exposure assessments are based and to enforce statutory maximum residue limits (MRLs) that are set. Diminazene aceturate is one of the few drugs used for animal trypanosomosis. Because of it's wide use in livestock, the risk of unwanted residues in edible products may exist. A competitive enzyme-linked immunosorbent assay (ELISA) for determination of diminazene residues in edible animal tissues after extraction in 0.1 M borax at pH 9.7 was investigated. The assay used rabbit anti-diminazene polyclonal antibody on the solid phase support. Horseradish peroxidase-labeled diminazene was incubated with sample overnight at 4°C. After five washes with buffer enzyme activity was determined by adding tetramethyl-benzidine and hydrogen peroxide as substrate. The resulting blue colour whose intensity was inversely proportional to the drug concentration changed to yellow when the reaction was stopped by addition of 0.1 M orthophosphoric acid. The assay was optimized and validated for determination of diminazene in tissues. The assay exhibited high specificity (99.997%) for diminazene recognizing only isometamidium at 0.003% and this may be contributed by the amidinophenyl that is common in both drugs. Recoveries from spiked tissues were above 77% while Dilutional parallelism experiments demonstrated a recovery of 96.0% ± 9.5%. The limit of detection (LOD) for the assay was 2.4ng/g for muscle, 2.5ng/g for liver and 2.2ng/g for kidney while limits of quantification (LOQ) were 5.51 ng/g, 4.11 ng/g and 3.74 ng/g respectively. The LODs are 4.4x103 to 3.5xl03 lower than the MRLs that are 500mg/kg, 12,000m/kg and 6,000mg/kg of muscle liver and kidney respectively. Assay precision was characterized by a within assay coefficient of variation (CV) of 2.4% and between assays CV of 15.5%. When diminazene was administered intramuscularly at 3.5mg/kg to five goats that were sacrificed seven days later, the mean diminazene residue levels were 0.75mg/g±0.14mg/g for skeletal muscle, 32.05mg/g±5.7mg/g for liver and 4.29mg/g±0.66mg/g for kidney. The analysis of tissue samples collected from slaughterhouses around Nairobi showed that out of 35 muscle samples, only one was positive and had a diminazene concentration of 0.039 !ig/g. Four out of 32 kidney samples were positive for diminazene with levels of 0.63, 1.66, 2.61 and 3.96mg/g. From ten liver samples two were positive with levels of 1.07 and 1.74pg/g. From this analysis none of the positive samples had levels above the MRL values. This study has demonstrated that competitive ELISA can be employed for the determination of diminazene residues. The results of this study are relevant to food scientists, toxicologists and analysts working in the area of detection and safety assessment of food residues, companies developing veterinary drugs, regulatory bodies involved in safety assessment of veterinary drugs and residue monitoring and to regulatory bodies responsible for veterinary drugs registration.
Adaptation of an enzyme-linked immunosorbent assay for determination of diminazene aceturate in goat serum and tissue residues of animals
(2014-11-27) Karanja, Wycliff
The importance of food safety through the reduction of residues in our food supply cannot be overemphasized. Food safety remains a major challenge confronting contemporary society. Analytical methods are needed to generate the data on which dietary exposure assessments are based and to enforce statutory maximum residue limits (MRLs) that are set. Diminazene aceturate is one of the few drugs used for animal trypanosomosis. Because of it's wide use in livestock, the risk of unwanted residues in edible products may exist. A competitive enzyme-linked immunosorbent assay (ELISA) for determination of diminazene residues in edible animal tissues after extraction in 0.1 M borax at pH 9.7 was investigated. The assay used rabbit anti-diminazene polyclonal antibody on the solid phase support. Horseradish peroxidase-labeled diminazene was incubated with sample overnight at 4°C. After five washes with buffer enzyme activity was determined by adding tetramethyl-benzidine and hydrogen peroxide as substrate. The resulting blue colour whose intensity was inversely proportional to the drug concentration changed to yellow when the reaction was stopped by addition of 0.1 M orthophosphoric acid. The assay was optimized and validated for determination of diminazene in tissues. The assay exhibited high specificity (99.997%) for diminazene recognizing only isometamidium at 0.003% and this may be contributed by the amidinophenyl that is common in both drugs. Recoveries from spiked tissues were above 77% while Dilutional parallelism experiments demonstrated a recovery of 96.0% ± 9.5%. The limit of detection (LaD) for the assay was 2.4ng/g for muscle, 2.5ng/g for liver and 2.2ng/g for kidney while limits of quantification (LOQ) were 5.51ng/g, 4.11 ng/g and 3.74 ng/g respectively. The LaDs are 4.4x103 to 3.5x103 lower than the MRLs that are 500llg/kg, 12,000Ilg/kg and 6,000Ilg/kg of muscle liver and kidney respectively: Assay precision was characterized by a within assay coefficient of variation (CV) of 2.4% and between assays CV of 15.5%. When diminazene was administered intramuscularly at 3.5mg/kg to five goats that were sacrificed seven days later, the mean diminazene residue levels were 0.75Ilg/g±0.14Ilg/g for skeletal muscle, 32.05Ilg/g±5.7Ilg/g for liver and 4.29Ilg/g±0.66Ilg/g for kidney. The analysis of tissue samples collected from slaughterhouses around Nairobi showed that out of 35 muscle samples, only one was positive and had a diminazene concentration of 0.039 ug/g. Four out of 32 kidney samples were positive for diminazene with levels of 0.63, 1.66,2.61 and 3.96Ilg/g. From ten liver samples two were positive with levels of 1.07 and 1.74 ug/g. From this analysis none of the positive samples had levels above the MRL values. This study has demonstrated that competitive ELISA can be employed for the determination of diminazene residues. The results of this study are relevant to food scientists, toxicologists and analysts working in the area of detection and safety assessment of food residues, companies developing veterinary drugs, regulatory bodies involved in safety assessment of veterinary drugs and residue monitoring and to regulatory bodies responsible for veterinary drugs registration.
Adoption of biogas technology as an alternative energy source in Gakawa Location, Nyeri County, Kenya
(Kenyatta University, 2018) Otondi, Ronald Nyakweba
Tsetse flies (Glossina spp.) are vectors of Animal African Trypanosomiasis and Human African Trypanosomiasis. Two approaches have been used to combat the diseases: parasite and vector control. Parasitic control by trypanocidal drugs has so far failed due to problems of availability, toxicity and resistance development. Vector control by use of insecticides is ineffective. Trapping using baits have been relatively successful, except among pastoralists. Integration of repellants and attractants to create push-pull strategy may provide an effective control tactic at individual farmer and pastoralist level. A previous study on waterbuck, led to the identification of a blend of 15 electrophysiologically active constituents: six C8-C13 methylketones, two phenolic compounds, six C5-C10 fatty acids and δ-octalactone that is repellant to savanna tsetse flies. δ-Octalactone has been shown to singly elicit allomonal responses, and a follow-up study has shown that its structural modification can bear both repellants and attractants. In the present study, the effects of some δ-octalactone analogues on two Glossina spp. were carried out to elucidate their activities. (RS)-3-propylcyclohexanone (15) and (RS)-δ-valerolactone (16) and were synthesized and their structures confirmed using spectroscopic techniques, while 2-propyloxane (14) and (RS)-3-propylcyclohex-2-enone (17) were acquired commercially. The responses of the two Glossina spp. to each of the four analogues were determined in a two-choice wind tunnel. Data collected were subjected to Analysis of Variance and means ranked using Student-Newman-Keuls test and the tsetse preferences were compared using t-Test. In the bioassays, it was noted that (RS)-δ-valerolactone (16) and (RS)-2-propyloxane (14) elicited avoidance; whereas (RS)-3-propylcyclohex-2-enone (17) and (RS)-3-propylcyclohexanone (15) elicited attraction. There was no significant difference between the repellency of (RS)-δ-valerolactone (16) and 2-propyloxane (14) (p > 0.05) to both Glossina spp. However, the repellency of both, (RS)-2-propyloxane and (RS)-δ-valerolactone, were significantly lower than that of δ-octalactone (5) (p < 0.05). When (RS)-δ-valerolactone (16) and (RS)-2-propyloxane (14) were blended it was noted that the repellency was comparable to that of δ-octalactone (5) (p > 0.05) when G. pallidipes were deployed, but there was no significant improvement in repellency against G. m. morsitans. The attractancy of (RS)-3-propylcyclohex-2-enone (17) and (RS)-3-propylcyclohexanone (15) to the two tsetse species were comparable (p > 0.05). Blending the two attractants did not lead to any change to both tsetse species (p > 0.05). The study identifies potent attractants and repellants on the two Glossina spp. and therefore lays a useful basis for the development of more effective behavioural control of the tsetse species
Adsorbent Materials from Rice Husks and Water Hyacinth Ashes Blended with Bone Char for Removal of Fluoride Ions from Contaminated Water
(Kenyatta University, 2020-11) Gitonga, Rose Kagwiria
Safe and readily available water is important for public health, whether it is used for drinking, domestic use, food production or recreational purposes. Consumption of contaminated water may lead to acute and chronic health effects. The most common water pollutants include heavy metals, pesticides, and anions such as fluorides, arsenic, arsenite, chromate and selenate, which cause various diseases such as brain, liver and bone ailments. Among the pollutants, fluoride is the most occurring contaminant in water. Fluoride ions are absorbed by the body mainly through drinking water containing a concentration of more than 1.5 mg/L for a long period of time. At high levels, they cause health problems which range from mild to severe teeth and bone fluorosis. Many methods have been used for removal of anionic contaminants such as fluoride from drinking water. These methods include reverse osmosis, precipitation, electro dialysis and adsorption. Most of these methods are too expensive. This study aimed at synthesizing an adsorbent material from low cost agricultural waste products materials namely water hyacinth ash (WHA) and rice husks ash (RHA) blended with bone char and determine its effectiveness in removal of fluoride ions from contaminated water. Five zeolitic materials were prepared and labelled as zeolitic A (ZA), zeolitic B (ZB), zeolitic C (ZC), black bone char (BBC) and white bone char (WBC) by varying the amounts of rice husks and the water hyacinth ashes and blending with white and black char. Analysis of various oxides contained in the adsorbents was done by X-ray Fluorescence Spectrometer (XRF). Adsorption tests for fluoride ions by the five adsorbents were carried out based on the batch adsorption studies. These include varying the shaking speed, temperature, contact time, initial anion concentration and adsorbent dose. The concentration of fluoride ions remaining in the solution after adsorption was analysed using Fluoride Ion Selective Electrode (FISE). Results for the adsorption capacities for the five adsorbents fitted best onto Freundlich isotherm model which gave adsorption capacity (Kf) values as follows; ZA 1.181, ZB 1.281, ZC 1.061, BBC 1.142, BWC 1.112. The zeolite B had the highest adsorption capacity. This indicates that blending a zeolitic material by black bone char improves its adsorption capacity for fluoride ions from contaminated water. At optimum concentration of fluoride ion and optimum temperature, ZB removes 75.50% and 80.00% of the ion respectively. It gives 75.50% at a shaking speed of 120 rpm and 77.00% at optimum contact time. Therefore it is necessary to optimize use of locally available materials for application in defluoridation of water.
Adsorption of Selected Heavy Metals Using Modified Pennisetum Purpureum Plant Stalks: A Case Study of River Ruiru, Kiambu County, Kenya
(Kenyatta University, 2022) Murage, Daniel; Eric Masika; Alphonse Wanyonyi
Water pollution is a global problem affecting the welfare of humanity. Availability of clean water is a fundamental prerequisite to public health safety and the survival of the human race as well as animals. However, pollution of river water by heavy metal ions deposition is a grave ecological problem especially in developing countries. Previous research work on analysis of fish, soil sediments and water samples obtained from Nairobi and Ruiru river confirmed the presence of heavy metals. These metal ions which include lead, chromium, and iron are mainly from industrial effluents discharged into the rivers. Presence of the heavy metals in the water, pose a serious health risk particularly to rural populations which rely majorly on the river water for domestic purposes. Several methods for elimination of the heavy metal pollutants from river waters have been previously employed. However, most of these methods have proved to be expensive and cumbersome, hence not sustainable. Simpler methods are, therefore, needed for better sustainability. This research explored the potential of modified Pennisetum purpureum plant adsorbent in eradication of lead (II), manganese (II) and chromium (VI) ions from Ruiru river water by adsorption process. Sampling was done at three different locations along the river, that is, Ruiru Town, Juja Farm and Fourteen Falls. The mean concentration of heavy metal ions was determined before and after the adsorption process in triplicates using Atomic Absorption Spectroscopy (AAS). Effect of changes in pH on adsorption was investigated by conducting adsorption at pH of 5, 7 and 9. Data was organized in excel worksheets before it was transferred into SPSS software for analysis. The results show high chromium and lead pollution of the Ruiru river. Average concentrations of chromium and lead were 1.495±0.09 ppm and 1.610±0.1 ppm respectively. Average Manganese levels were 0.05±0.01 ppm which was within the permissible level (0.5 ppm). Modification of the adsorbent surface improved its adsorption capacity. The modified adsorbent achieved greater % adsorption in all the three metals. Increase in the pH of adsorption from 5 to 9 had a reducing effect on the percent adsorption of metal ions from water samples with significant reductions in % adsorption being recorded for lead and manganese ions but not for chromium ions. These results show the potential of the Pennisetum purpureum plant in the purification and detoxification of river water by adsorption. This adsorbent presents a more readily alternative to many current adsorbents and adsorption methods in use. However further research is needed to ascertain the best set of conditions as well as the most suitable modification treatment for maximum adsorption.
Aflatoxin Detection Rate Using Urine Immunoassay and Compliance Level with Control Strategies among Makueni Residents Attending the County Hospital
(Kenyatta University, 2023-11) Buuri, Kaburia Martin; Michael Gicheru; Joshua Mutiso
Aflatoxicosis is caused by Aflatoxins. The pathogenic fungi responsible are A. parasiticus and A. flavus that contaminate foods such as maize, rice, groundnuts, sorghum, wheat, millet and cassava among others. Aflatoxins mainly cause health issues that target the liver with fatal consequences. Aflatoxin toxicity range from acute to chronic and disease severity depends on age, diet, nutrition quality, extent of exposure, pre-existing health issues and gender. Preventive strategies are mainly focused on proper pre- and post-harvest food handling especially cereals. Aflatoxicosis is highly prevalent in the eastern region of Kenya despite the existence of preventive measures. The present study was carried out in Makueni County at the County referral hospital, which was selected purposively because it had the highest death rate during the 2004 aflatoxin-poisoning outbreak. The study aimed at establishing the detection level of aflatoxicosis using the Aflatoxin M1 (AFM1) urine immunoassay as well as evaluating the level of compliance to the aflatoxin preventive strategies put in place and challenges associated with control of aflatoxicosis by residents of Makueni County. A cross-sectional design was chosen for the study in which one hundred and six volunteers took part. Data were obtained via questionnaires and urine samples were analyzed for presence of Aflatoxin using Aflatoxin M1 immunoassay. Collected data were entered into an excel worksheet and later analyzed using SPSS version 20 with a P value considered significant at < 0.05. Results showed that 99.1% of study participants had AFM1 in the range of 25-2337 pg./ml, with a mean concentration of 637.6 ± 512.7. Notably, majority (n=82; 77.4%) of the residents knew the negative effects of aflatoxin on their health. Additionally, the sampled residents had a compliance rate of 72.6% (n=77) while 26.4 % were not compliant to mitigation measures put in place to minimize aflatoxin contamination. At the baseline, while 67.9% of the residents indicated that handling of cereals hygienically and using proper means to dry and store their farm produce, 1.9% reported that smoking of cereals was the most effective means to prevent aflatoxin contamination. It was concerning that, 29.2% of the residents did not know which method of cereal handling was the most effective in controling aflatoxins. The study concludes that the present prevalence of aflatoxicosis in Makueni County is high despite high rate of compliance with aflatoxins preventive measures. The study recommends further research to be carried out on better aflatoxins preventive methods and the residents to be educated on proper application of mitigation strategies in order to achieve effective control of aflatoxicosis.
Age related mating behaviour and bioassay of the synthetic sex pheromone of the spotted stem borer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae)
(2012-05-04) Njogu, Florence Njeri
The influence of age on the mating behaviour of Chilo partellus (Swinhoe) was investigated. The observations on the behaviour of 0-, 1-, and 3-day-old months were carried out to ascertain if any changes occurred relative to age in attractiveness of the females and in the responsiveness of the males. The results showed that males were more attracted to 0-day old females than to 3-day old ones. No difference in attractiveness was found between 0- and 1-day old females. 0-day old males were found to have a significantly lower responsiveness to the females than both 1- and 3-day old ones. However, although 3-day old males were more responsive than 1-day old ones, this difference was not found to be significant. Observations of the mating behaviour of the moths showed that there were quantitative differences in the behaviour of 0-day old males and 3-day old ones. 0-day old males were found to spend the largest proportion of the time passive and only very few of them copulated by the end of the observation period. On the other hand, 3-day old males spent a relatively smaller proportion of the time passive and most of them had mated by the end of the observation period. No significant differences were detected between the behaviour of the laboratory reared and the field collected insects. The effect of proximity of release points of the two pheromone components (Z)-11-hexadecenal and (Z)-11-hexadecen-1-ol of the female moth were investigated. Separating the dispensers of the two components by a mere 3 cm resulted in a significant change in the male behaviour and a decrease in the bait performance as compared to the dispensers with the two components dispensed close to each other. A study to establish the effect of polyvinyl chloride (PVC) on the response of the male C. partellus to the synthetic blend of the sex pheromone of the female showed that PVC does not inhibit male response to the pheromone. It was found, however, that the PVC dispenser loaded with the alcohol was inferior in its performance to the filter paper dispenser loaded with the same and this could possibly be attributed to a lower release rate of the alcohol by PVC.
Agrobacterium mediated transformation of selected maize inbred lines with ppzp200 towards enhancment of lysine and methionine content
(2012-03-26) Limbua, Purity Gacheri; Machuka, Jesse; Ombori, O.
Maize (Zea mays (L.) is one of the most important cereals used both for human and animal consumption in the world. Despite its importance, maize is not a suitable single source of nutrition because it does not provide the essential amino acids lysine and methionine in sufficient quantities to meet the nutritional needs of humans and other animals. Lysine is a necessary building block for protein in the body while methionine is the body's primary source of sulphur. Strategies to improve the nutritional quality of maize for high lysine and methionine have involved both genetic engineering (GE) and non-genetic engineering approaches such as marker assisted selection. Breeding is however laborious, lengthy and carries along undesired alleles. The objective of this work was to manipulate maize inbred lines towards enhancement of lysine and methionine content in the endosperms through Agrobacterium mediated transformation. Maize kernels mainly store proteins as a, {3, y and 0 zeins. The immature embryos of three tropical maize inbred lines (TL IS, CML216 and CMLI44) and a temperate line (AlSS) were transformed using Agrobacterium tumejaciens strain EHAI01 carrying an expression cassette designed to upregulate the Z I 0 protein for methionine enhancement as well as down-regulate the a. zein storage protein by RNAi. The T -DNA also contained P-zp22/6 as the promoter and the phosphinothricin acetyltransfarase gene (bar) used for selection of transformed tissue. Putative transformants were tested for presence of the transgene by PCR designed to amplify the P-zp22/6 promoter sequence. Calli survival frequencies were calculated as a percentage number of surviving calli in relation to the total number of embryos infected. These ranged from 2.S9 % forTLIS to 9.11 % for AISS. This data did not detect any significant difference (p>0.05) among the genotypes on the percentage of calli which survived. Transformation efficiency was calculated as a percentage of the number of PCR positive plants divided by the total number of embryos infected. This ranged from 0% for TLIS to I.S3% for AISS. The data suggest the possibility of manipulating storage proteins and regenerating normal transgenic maize with normal kernels. Further work should involve gene expression assays for accumulation of {3, y and 0 prolamins in the kernels and southern blot analysis to confirm stable integration and the copy numbers ofPzp22/6 gene in the PCR positive plants.
Agrobacterium tumefaciens mediated transformation of Sudan maize genotypes using NPKI gene for enhancing drought stress tolerance
(2011-11-29) Abdalla, Rasha Adam Omer; Jesse Machuka; Abdelbagi M. Ali
Drought is one of the most important abiotic factor affecting maize production worldwide. Agrobacterium-mediated gene transfer technique has been established as a versatile way of improving important crops for tolerance to biotic and abiotic factors. Through this technique, the drought tolerance gene, NPKI, has been used in the transformation of temperate maize after its isolation and characterization from tobacco. Recovered transgenic events were observed to have enhanced tolerance to water stress. The accelerated adoption of the transformation technique in Africa, and indeed in Sudan, will depend on the ease with which transgenes of agronomic importance can be integrated into appropriate germplasms. This study aimed at screening important Sudanese maize inbred lines and open pollinated varieties (OPVs) for transformability via the integration of the NPKI gene. Eight inbred lines and three OPVs were evaluated. A188 was used as the standard inbred line check while KAT was used as the local OPV check. Freshly isolated immature embryos of maize were inoculated with Agrobacterium strain EHA101 harbouring the plasmid pSHX004 in LS infection media for 5 minutes and then co-cultivated on LS cocultivation media for 3 days. Embryos were then transferred to selection media supplemented with 250mg/l cefotaxime and 1.5mg/L bialaphos. After two weeks on this media, calli were subcultured on selection media containing 3.0 mg/L bialaphos for 4 weeks. Bialaphos resistant callus events were then transferred to maturation media supplemented 3mg/L bialaphos for 2 weeks before transferring to shooting media. Shoots were then transferred to rooting media. Plantlets with well-formed root system were transferred from the in vitro environment to green house for hardening. Hardened plantlets were transplanted to soil in the greenhouse and maintained till they set seeds. To confirm the presence of the transgene, PCR analysis was done on putative transgenic plants using the Bar primers. Out of a total of 4401 immature embryos from the 13 genotypes infected, 327 survived selection in bialaphos. Bialaphos resistant calli emerged 3-4 weeks after selection. IL3, IL15, Hudiba-2, IL1, IL38, Hudiba-1, A188 and KAT produced compact calli from their scutella surfaces while IL28, IL42, IL43, Mojtamaa-45 and IL16 established watery nonembryogenic calli. Statistically significant differences (p<0.05) were observed between the genotypes with respect to transformation frequency (TF). IL3 was identified as the most amenable to transformation with a TF of 31.7% and proved to be superior to A188, which recorded a TF of 5.82%. Hudiba-2 was identified as the most transformable OPV with a TF of 8.7% compared to that of 7.3% for KAT. ILI and Mojatamaa-45 proved to be poor responders to transformation with TFs of 2.5% and 1.7%, respectively. Putative transgenics were recovered from IL3, IL 15, Hudiba-2, ILI, IL38, Mojatamaa-45, A188 and KAT. The frequency of regeneration of bialaphos resistant shoots varied from 6.9% for IL38 to 100% for Mojtamaa-45. PCR analysis indicated a 540bp fragment in the DNA extracts from transgenic R, plants. Transformation efficiency (TE) was found to depend on the genotype used. The highest TE was observed for IL3 (3.7%), while the lowest TE of 0.0% was observed in IL42 IL43, IL16 and 11,28. Various abnormalities were observed in putative transformants including dwarfism, tussel seed and lack of ear. However, plants grew to maturity and were able to establish seeds in spite of these abnormalities. In conclusion, the inbred line IL3 and the OPV Hudiba-2 proved to be the most amenable Sudanese genotypes to A. tumefaciens-mediated transformation. Future research in maize improvement through biotechnologies such as tissue culture and genetic transformation should be focussed on these good responders.
Agrobacterium tumefaciens-mediated transformation of three groundnut (Arachis hypogae L.) genotypes from Southern and Eastern Africa
(2012-03-26) Kahariri, Esther Wanja
Groundnut or peanut (Arachis hypogae L.) is one of the principal economic oilseed legumes and "is largely cultivated in tropical, subtropical and warm temperate regions of the world. It is an . upright or prostrate annual plant. Groundnut contributes significantly to household food security and cash income through the sale of the seeds and also provides a valuable source of proteins, .. fats, energy and minerals. Developing countries account for nearly 9S% of the world production .Groundnut production in African countries has been fluctuating greatly over the last decade. This has been attributed to biotic and abiotic constraints. Pests and diseases that are major biotic factors can lead to yield losses as high as 100% resulting in total crop failure. Traditional plant breeding methods used to improve the crop are time consuming, expensive and involve transfer of unwanted traits along with the desired ones. Besides they are limited to the existing narrow gene pool within compatible groundnut genotypes. Recent advances in biotechnology offer alternative tools such as genetic engineering through which genes that confer some of these traits can be isolated, cloned and introduced into important crops. Genetic transformation protocols are both genotype and species dependent and specific protocols need to be developed for every plant species and sometimes even each genotype. Development ofa good transformation protocol for African groundnuts will provide a platform for further genetic improvement for traits such as drought, pest and disease resistance and biofortification. Transformability of three groundnut genotypes; ICGV90704, ICGV12991 and JL24 was assessed using cotyledon explants from mature seeds infected with four Agrobacterium tumefaciens strains AGLO, EHA lOS, CS8 and LBA 4404 containing a standard binary vector with a GUS reporter gene. The transformation efficiency (TE) expressed as a % of PCR positive shoots out of the total number of shoots infected, of groundnut variety ICGV90704 was 1.33% with strain EHAI0S, 0.81% with strain AGLO and 0.39% with strain LBA4404. Variety ICGV12991 recorded a TE of 1.11% with strain AGLO, 0.S9% with strain CS8 and 0.53% with strain LBA4404. Variety JL24 had a TE of 1.03% with strain AGLO and 0.99% with strain CS8. ANOV A between and within the three varieties at the explant producing shoots, total shoots in S 1, total shoots in S2 and total shoots in RIM showed strain LBA4404to be more efficient followed by AGLO and EHAI0S. The least efficient strain wasCS8. Groundnut variety ICGV 90704 was found to be the most amenable to transformation. It is concluded that cotyledons can be used as explants in the transformation of African groundnuts.
Agrobacterium-Mediated Transformation of Elite Kenyan Maize Germplasm with CRY3A Gene for the Control of the Larger Grain Borer and Maize Weevil
(2013-10-18) Taracha, Catherine Ongecha
In Kenya maize (Zea mays L.) is the most important staple food. Owing to its predominant role, food security in the future cannot be achieved without major increases in cereal production. An efficient in vitro regeneration and transformation system holds a great potential for genetic improvement of maize against production constraints. This study was conducted with the objective of assessing the regenerative capacity, genetic transformation of Kenyan maize genotypes and efficacy of transformed maize in controlling maize pests. Six Kenyan inbred lines and four CIMMYT lines and their single crosses were evaluated for their in vitro response on three different media (MS, N6 and N6CL). The embryogenic callus induction and regeneration capacity was higher on MS than on N6 basal salts. Plant regeneration was influenced by genotype. Transformation experiments were carried out using Agrobacterium tumefaciens strain EHAI01 containing pTF 102 binary vector harbouring a GUS gene. The transformation frequency was highest in 104 (15.2%) and lowest in QPM. The highest transformation efficiency was recorded in inbred T04, 104 and their crosses . with CML 216 and ranged 2.4% to 3.0%. The transgene was detected in all the maize genotypes using GUS assays, and PCR. Maize genotypes were transformed using a Bacillus thuringiensis tenebrionis gene Cry3A. The highest transformation frequency was recorded in three inbred lines, H04, T04 and 104 (9.3%, 12.2% and 13.4% respectively). The transformation efficiency ranged between 0.5% to 2.5%. PCR and RT-PCR amplification of the Cry3A gene, and the l)AS-Elisa confirmed the presence of the gene To,T1 and T2 generations. 'Insect bioassays established that transgenic maize provided protection against the larger grain borer and maize weevil This study established a reproducible regeneration and transformation system for tropical maize, which can be used in a pest management programme
Agronomic and Rodent Pests Management by Maize Farmers in Rongai Division, Nakuru County
(2013-03-21) Mutinda, Anna Mukunya
Rodent damage to maize and other cereal crops is a chronic problem to Kenyan farmers and occasional outbreaks are reported. According to a report by the Ministry of Agriculture in the year 2008, damage of between 1 and 5 % are common but damages of 20-100 % have also been recorded. In this study, a survey was carried out in Rongai Division, a cereal growing region in the Kenyan Rift Valley, to identify the general crop husbandry and farm enterprises, knowledge on problem rodents, farmers' perception of the rodent pest problem and their management practices amongst the small-holders. The data was collected using a structured questionnaire administered to 278 farmers in RongaiDivision, Nakuru District. The structured questionnaire was based on three broad areas including agronomic practices, rodent pest problems and their control and farmer background information. Slightly over half (56.6%) of the farming population owned less than 5 acres and only 14 (5.1%) of the interviewed farmers owned more than 20 acres. The age of the respondents ranged between 18 and 90 years and averaged 43 years. Maize was grown by over 91 % of the farmers either for subsistence (48.8%) or for both subsistence and cash (49.~%). Weeding was manually done (92.4%) and 62.2% of the respondents weeded twice before harvesting the crop. The main mode of harvesting maize was cutting and 'stooking' (68.5%). Farmers described the rodent pests problem as a regular (65.7%) or an occasional (30.6%) phenomenon. Maize was damaged at all phenological stages and most damage occurred in the fields 53.6% and stores 39.2%. Control was done individually (94.2%) by use of chemicals (26.6%), cats and dogs (63%) and varying combination of other methods (10.4%). Control measures were undertaken only when rodent signs were seen (41.8%) or when damage was obvious (21.7%). Acute rodenticides were used because of the perceived efficacy (58.1%). Rodent control was considered as a very important (49%) or just important (45.2%) practice, Farmers preferred to continue controlling the rodents individually (46.5%) although some suggested group (21.9%) control. Information on rodent control was largely obtained from the neighbours (44.2%). The agro-vet stockists (20.9%), radio (14.0%) and agricultural extension agents (11.6%), respectively, also contributed to such knowledge. Perceived maize crop losses to rodents was moderate (65.1%) to very severe (22.3%) yet some (12.6%) farmers reported they experienced no loss. However, there was no significant difference in severity of losses with different methods of harvesting maize (X2 = 5.320, P = 0.256). Occurrences of damage of ripened crop were more frequent (66.1%) under cut and 'stook' than other modes of harvest. Rodents were also ranked high (75%) as pests amongst the farmers who were using the cut and stook method. Thus, other modes of harvest (e.g. Cut and curry, direct removal of cobs) should be encouraged. Most farmers expressed need for control to be a continuous process, protecting the crop at all stages. Thus, there is a need to train farmers on an integrated approach to rodent pests control. It is also important to conduct research on some of the control methods identified by the farmers to check for possibility of recommending and up-scaling the same.
Agronomic evaluation and molecular genotyping of selected soybean (glycine max (l) merril) varieties grown in different environmental regions of East Africa
(2013-09-06) Okwany, Zedekiah W. Agina
Soybean (Glycine max. (L)Merril) is one of the most popular pulses in the world. It has been known to man for a long time since its first record goes as far as 2500 BC in China and Manchuria. Glycine max belongs to the subgenus soja, which also contains G. soja and G. gracilis. Soybean is grown primarily for the production of seed, has a multitude of uses in the food and industrial sectors, and represents one of the major sources of edible vegetable oil and of proteins for livestock feed use. Genes greatly determine morphological characteristics of living organisms. Environmental conditions may also determine these characteristics, some of which are important in agronomy. This study aimed at investigating the relationship that exists between agronomic and molecular characteristics of selected soybean cultivars grown in different regions of East Africa. The results will be used to advice both the farmers and researchers on the cultivar they cultivate/study and their relationship to agronomic value respectively. This information will also be used in breeding programmes. In this research, different soybean cultivars from different regions of East Africa (Kenya, Uganda and Tanzania) were grown in different blocks within one region (Mbita point in Kenya). Agronomic characteristics were observed and recorded from germination to post harvest time. For molecular analysis, genomic DNA was extracted according to Phenol Chloroform method. This was followed with PCR process using custom ordered pair of primers that corresponded to the flanking ends of the targeted gene fragment (5S ribosomal genes). Restriction Fragment Length Polymorphism (RFLP) was then performed on the isolated PCR fragments by digesting DNA using various restriction enzymes determined by computer based simulation of already sequenced genes of known Glycine species. Gene clean was performed on PCR materials. The elute was confirmed on agarose gel then sent for automated sequencing ABI prism (AppliedBiosystems) at (ILRI). The resulting gene sequences were compared with gene sequences of known Glycine species using various enzymes in computer based simulations. This enabled get a marker (Sac II) for the 5S ribosomal genes in Glycine max. The gene sequences were then subjected to gene blast using MEGA 4 and resulted with a phylogenetic tree for the East African soybean. The studied cultivars were found to be closely related to Glycine max. RFLP results were compared with agronomic performance. There was significant difference in plant height (F= 106.131, df = 12, p<0.05); number of branches (F=25.227, df =12, p<0.05); weight of the whole plant (F = 6.634, df = 12, p<0.05); total number of seeds per plant from the various cultivars (F = 13.330, df = 12, p<0.05); weights of total seeds per plant from various cultivars (F = 5.124, df =12, p<0.05). Significance differences observed in various parameters analysed in this study were not reflected in the cultivars’ genetic characteristics. The marker (sac II) identified in this research will be useful in further research in soybeans. The best performing cultivars (TGX-1876-2E, Namsoy 4M, Nam II and Nyala) will also be recommended for soybean farmers around Lake Victoria region. These results will also assist plant breeders to produce hybrids from the best performing cultivars.
An alternative route for manufacture of diammonium phosphate
(2011-08-23) Mutenyo, Maximilla Makhanu
The present study was undertaken with the aim of producing Diammonium Phosphate (DAP) using air as a source of nitrogen and bones as source of phosphoric acid. Oxygen was removed from air by passing air over heated copper granules in the temperature range of 300°C - 500°C. Copper granules were heated using charcoal packed in a ceramic charcoal stove e. The nitrogen was reacted with lithium to form lithium nitride which was hydrolysed to produce ammonia. The phosphoric acid extracted by boiling bones with concentrated hydrochloric acid or phosphoric acid was reacted with ammonia produced from hydrolysis of lithium nitride to form diammonium phosphate. The percentage concentration of phosphorus in the fertilizer was determined using U. V spectroscopy whereas that of nitrogen was determined by titration. The cost of energy for the production of one tone of DAP using this procedure was calculated and results show that the total energy required was 4.95 GJ. This is equivalent to 1375 kW. The cost of basic materials operational costs and production costs) of producing one tone of DAP using this procedure was found to be $1070.88 while the estimated cost of regenerating lithium from lithium chloride was 1.26 GJ, which is equivalent to 350 kW

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