MST-Department of Biochemistry and Biotechnology
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Item Phytochemical Composition, Antidiarrheal Activity and Antibacterial Effect of Aqueous Leaf Extract of Plectranthus Barbatus (Andrews)(Kenyatta University, 2024-05) Ajwang, Emmah ClariceDiarrhea is defined as the movement of unformed or watery stool more than three times a day. Globally, diarrheal infections remain a public health problem, especially in children. With nearly 1.7 billion episodes and 1.3 million fatalities reported annually. Developing countries bear 78% of diarrhea burden worldwide. A range of viral, bacterial, and parasitic species induce diarrhea in humans, including rotavirus and Escherichia coli. The mainstays of pharmacological therapy for infectious diarrhea include probiotics, antibacterials, antiviral drugs, and intestinal adsorbents. However, these clinical treatments are not devoid of shortcomings, including prohibitive costs, drug-drug interactions, and adverse effects such as lethargy, constipation, respiratory depression, and coma. Medicinal plants, including Plectranthus barbatus have folkloric remedies against diarrhea. However, there is a paucity of knowledge to scientifically validate the efficacy of the leaves of P. barbatus on diarrheal infections. The study, therefore, was undertaken to ascertain the antidiarrheal efficacy, antibacterial activity, bioactive composition, and toxicity profiles of P. barbatus aqueous leaf extracts. Antidiarrheal activity and acute toxicity were carried out on mice. Using Swiss albino mice, castor oil-induced diarrhea, charcoal meal-based gastrointestinal motility, and castor oil-induced secretion models were employed to assess antidiarrheal activity. In all of the test models, animals were randomly assigned into six groups consisting of six animals in each. Group I received distilled water, group II received 10 ml/kgbw of the vehicle (distilled water), while group III was treated with standard drug (3 mg/kgbw loperamide) in the respective models, whereas groups IV to VI received 100, 200, and 400 mg/kgbw of the aqueous leaf extracts of Plectranthus barbatus. Antibacterial activity was carried out on selected bacterial pathogens. Quantitative phytocompound analysis was evaluated using liquid chromatography mass spectrometry. Data were analysed using one-way analysis of variance followed by Tukey’s test, and p< 0.05 was considered statistically significant at 95% confidence of interval.The study results indicated that P. barbatus extract has antidiarrheal activity. The plant extract prolonged the onset of diarrhea, caused a significant decline in the occurrence of wet feces and intestinal transit. Additionally, the extract elicited a reduction in the accumulation of intraluminal fluid, resulting in a decrease in distension, intestinal overload, and water content in the fecal drops. Loperamide showed a statistically similar antidiarrheal effect with the extract at a dosage of 200mg/kgbw suggesting a probable effective dosage of the extract. This study demonstrated that the aqueous leaf extracts of P. barbatus exhibited diarrheal inhibition activity. The percentage inhibition was dose dependent with 100, 200 and 400mg/kgbw showing 49.98±1.61, 66.12±2.17 and 75.80±2.16% inhibition of diarrheal output respectively (p<0.05). Further, P. barbatus demonstrated antibacterial activity against pathogens associated with diarrheal diseases. The extract had varying Mean Zones of Inhibition (MZI), 7.33±0.33 to 17.17±0.73mm, against the bacterial pathogens, with higher effects observed against P. aeruginosa and B. subtilis. Acute toxicity assays on mice showed that P. barbatus extract was non-toxic at the dosage level of 2000mg/kgbw. LC-MS analysis detected the presence of phytocompounds associated with antidiarrheal and antibacterial effects. Findings from this study offer scientific validation for the folkloric utilization of P. barbatus in the management of diarrhea. However, further studies should be conducted to explore the mechanistic approach to the reduction of diarrhea and the comprehensive chronic toxicological effects on biochemical and hematological parameters.Item Effects of Aqueous Extract of Spirulina Plantesis on Immunologic Dysfunction and Inflammation Associated with Aflatoxin B1-Induced Toxicity in Mice(Kenyatta University, 2024-06) Kipkoech, GilbertKenya is among African countries that face the burden of food contamination by aflatoxin. High levels of aflatoxins have been reported to kill 157 people in Kenya while also contributing to cancer burden. Aflatoxins are produced by Aspergillus flavus, Aspergillus parasiticus, Aspergillus and Aspergillus nomius. These toxins majorly affects cereal grains. This study aimed at bioprospecting Spirulina plantesis in ameliorating immune dysfunction and inflammation caused by aflatoxin B1 (AFB1). Spirulina plantesis have been consumed for decades as food supplement as it has been proven to have strong antioxidant and anti-inflammatory properties. Male BALB/c mice weighing 28 to 34 g were divided into six groups at random and given the following oral treatments: Group 1 was only provided with food and water during the treatment course. AFB1 was given orally to Group 2 at a dosage of 200µ g/kg body weight. AFB1 was administered orally to Group 3 an hour after receiving 1g/kg of activated charcoal. Groups 4, 5, and 6 each received 200µg/kg of AFB1 orally an hour after receiving Spirulina plantesis at doses of 50, 100, and 150mg/kg respectively. The mice were treated daily for 14 days. During the last day of the treatment schedule, mice were aseptically dissected and tissues isolated for immunological studies. The results indicate that intervention with spirulina at doses of 100mg/kg and 150mg/kg were enough to increase the body weight of mice significantly (p<0.05). It was also demonstrated the blood levels of interleukin 4 and interleukin 2 were not affected significantly when AFB1-induced mice are treated with spirulina extract (p>0.05). Interferon gamma (IFN- γ) and interleukin 2 (IL-2) blood levels were significantly lower in the group not treated with Aflatoxin b1 (p≤0.05). The findings also indicate that immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) serum levels were unaffected by treatment with spirulina extract at various dosages (p>0.05). In addition, TNF and IFN-γ mRNA expressions were also highly up regulated, while interleukin 4 (IL 4) was down-regulated. The results further show that the over-production of TNF and IFN due to Aflatoxin B1 is correctable upon spirulina treatment (p<0.05). To sum up, the results suggest that spirulina treatment can be an innovative approach to correcting the aflatoxin B1-mediated immune aberration and inflammationItem Performance of Glucose Challenge Test in the Diagnosis of Gestational Diabetes Mellitus in Antenatal Mothers at Kenyatta National Hospital, Nairobi, Kenya(Kenyatta University, 2024-04) Ndege, Martin K.Gestational diabetes mellitus is a disorder that affects women during pregnancy. It is glucose intolerance that is detected in pregnant women but reverses to normal after delivery; thus, it requires re-classification post-partum. It impacts approximately 4% of all pregnancies, with a prevalence of 1–14%. The statistics are dependent on the screening method and population. Early detection of GDM is essential to reduce the risks associated with delivery as well as potential long-term health concerns, such as metabolic and cardiovascular problems, for both the mother and the child. Nevertheless, diagnosing GDM in Sub-Saharan Africa (SSA) still faces challenges due to logistical constraints and the financial burden, particularly for populations with limited resources. It is therefore imperative to develop a practical and affordable method of screening for GDM in these contexts. Currently, OGTT is the confirmatory method in use. The OGTT procedure is cumbersome and difficult, costly and time-consuming with up to four blood collections from the patients. It is lengthy and requires the patients to fast; it is not user-friendly for antenatal mothers. As a screening method, GCT confers several advantages such as it is a one-step method that follows simple steps that are easy to remember, it reduces delay in diagnosis which consequently reduces delays in care and management. The method does not require patients to fast, can be performed at any time of the day, is cheaper than OGTT and is less time-consuming hence it can be used for both diagnosis and prevalence surveillance studies. It is much friendlier to the users and the technical staff, rendering it a more financially feasible option for both healthcare systems and patients, particularly in resource-limited settings. However, the use of GCT for screening for GDM has not been evaluated in Kenya. Consequently, the purpose of this study was to ascertain the prevalence of gestational diabetes mellitus (GDM) and evaluate the effectiveness of the Glucose Challenge Test (GCT) in detecting GDM in the Kenyan population. This was done by comparing the performance of GCT to OGTT which is the reference method in the investigation of GDM in expectant mothers. GCT and OGTT were performed on 107 pregnant and 84 non-pregnant women totalling 191 participants. 23 pregnant women (21.5%) had a diagnosis of GDM at 95% CI. Compared to OGTT, GCT had sensitivity, specificity, PPV and NPV of 73.91%, 86.9%, 60.71% and 92.41% respectively using a diagnostic cut-off of 7.8 Mm. Of the 23 (21.5%) with GDM, 12 were followed up, and 4 (33%) transformed to type II diabetes while 8 (67%) reversed to normal glucose levels. Of the common adverse outcomes of GDM in antenatal mothers, only excessive amniotic fluid had a significant impact (ρ = 0.048). The study concluded that there is a similarity in the specificity and sensitivity of OGTT and GCT in detecting GDM. Further, a significant GDM prevalence exists in antenatal mothers in the population under study. The MoH should develop policy guidelines for screening, counselling, and treatment of GDM among ANC mothers. GDM mothers should be followed up with to determine their postpartum status as Type 2 Diabetes. Based on the high prevalence of GDM among ANC mothers, this research recommends that the MoH adopt GCT for GDM screening. Additionally, ANC mothers should be educated about the traditional adverse outcomes associated with GDM.Item In Vivo Ameliorative Effects of Vitamin E Supplements against Hydralazine Induced Systemic Lupus Erythematosus(Kenyatta University, 2024-03) Githaiga, Fiona MuthoniSystemic lupus erythematosus (SLE) is a chronic autoimmune disease where the immune system attacks body cells and tissues causing inflammation. The drug therapy in SLE states that organ threatening disease should be managed aggressively by high to low doses of corticosteroids often followed by institution of steroid sparing measures in the form of immunosuppressive. Long term use of these drugs have life threatening side effects. Toxic oxygen radicals such as hydrogen peroxide have been associated with the development of SLE. The aim of this project was to evaluate the potential of an anti-oxidant, Vitamin E to eliminate the hydrogen peroxide levels in hydralazine induced lupus, a disease model that closely resembles SLE. The experiment involved forty Bagg Albino (BALB) c mice aged three to four weeks comprising of twenty females and twenty males that were randomized into six different groups. Each group contained three males and three females. To mimic the pathogenesis of SLE, hydralazine hydrochloride 25mg/kg bdw was used to induce a lupus-like condition in mice from groups B to F. The mice from group A received 1.0ml of sterile water and served as the normal control. An anti-nuclear antibody test was carried out every seven days to monitor the development of autoantibodies, which are considered a hallmark of lupus. By the 35th day post hydralazine administration, ANA antibodies were confirmed in all treated groups. Drug treatments were initiated in all lupus-induced mice at the same time, daily for a period of another 35 days with the exception of group B that served as the negative control of lupus induced mice with no drug treatment. Group C received prednisolone 25 mg/kg bdw, Group D received methotrexate 25 mg/kg bdw, Group E received Vitamin E 25 mg/kg bdw, and Group F received Vitamin E 50 mg/kg bdw. Only the higher dose of Vitamin E significantly eliminated the levels of lymphocyte hydrogen peroxide associated with the pathogenesis of hydralazine induced lupus. Both doses of Vitamin E protected lupus-induced mice from alterations in all blood cells. Mice from the methotrexate treatment groups recorded significantly low levels of all blood cells. However, the prednisolone group recorded significantly low lymphocyte count with eosinophil and neutrophil counts significantly high. Notably, the prednisolone treated mice had significantly increased platelet count. Both doses of Vitamin E protected the mice from changes in liver biomarkers while prednisolone and methotrexate treatment groups showed significantly high levels of liver enzymes. Both doses of Vitamin E protected from alterations in the lipid profile. Prednisolone and methotrexate treatment groups had high ANA titer concentrations, Mice treated with Vitamin E had significantly low ANA titers. Vitamin E also was found to prevent injury to the kidney, liver, spleen, heart and brain. Prednisolone group had significantly elevated bodyweight compared to the normal control group. In conclusion, this study found Vitamin E supplementation was able to counter oxidative stress associated with the pathogenesis of lupus. Based on these findings, Vitamin E supplementation may be beneficial for improving the condition of SLE patients. Further research is recommended to explore other relevant free radicals in SLE and determine the optimal dosage of Vitamin E to effectively eliminate free radicals associated with SLE.Item The Association between Toll-Like Receptor 4 (-8984c/G) and 299 Asp/Gly and Severe Malaria Disease in Children below 3 Years in Siaya County Western Kenya(Kenyatta University, 2024-05) Omwandho, John Robert CharlesThe high paediatric mortality and morbidity linked to Malaria in Africa is majorly caused by the parasite: Plasmodium falciparum with many complications characterized by severe anaemia and parasitemia. Severe Malaria Anaemia (SMA; Hb<5.0g/L accompanied by parasitemia of any density) manifests in young children below three years old. Nonetheless, the absence of understanding regarding the molecular underpinnings of SMA continues to hinder progress in creating successful treatments. Genetic susceptibility factors provide a means to decipher the intricate molecular processes at play. Toll like Receptor signalling pathways play an essential immunological role in helping to clear the parasites. However, the contributions of genetic variations to SMA pathogenesis are partially understood. Therefore, the study aimed to unravel the associations between Toll-Like Receptor 4 (-8984C/G) and 299 Asp/Gly polymorphisms and vulnerability to SMA and parasitemia. Samples from children (n= 426) diagnosed with malaria at Siaya County Referral Hospital were analysed. DNA extraction and genotyping were performed on dry blood spots using Gentra Systems Isolation Kit and TaqMan® 5' allelic discrimination Assay-By-Design high-throughput technique respectively. The association between Toll-like receptor-4 (-8984C/G) and 299 Asp/Gly polymorphism and SMA was determined using bivariate logistic regression analysis while controlling for anaemia confounders; Bacteraemia (co-infections) and HIV-1, alpha-thalassemia (traits) and sickle cell. The association between parasitemia and carriage of respective genotypes and haplotypes was done using Kruskal Wallis test/ Mann U Whitney where applicable. Bivariate regression analysis revealed that the TLR-4 (-8984 C/G) genotypes (GG vs. GC, OR = 0.53, 95% CI = 0.07-3.91, P= 0.533, and GG vs. CC, OR = 1.02, 95% CI = 0.12–8.82, P= 0.988) and TLR-4 +299 Asp/Gly genotypes (Asp/Asp vs. Gly/Asp, OR = 1.66, 95% CI = 0.42–6.50, P=0.471) were not associated with SMA. Further, haplotypes of TLR-4 -8984G and +299Gly (OR; 2.70, CI; 0.70-10.48, P= 0.151), TLR-4 -8984G and +299Asp (OR; 0.72, CI; 0.15-3.51, P= 0.682) and TLR-4 -8984C and +299Asp (OR; 1.29 CI; 0.56-3.63, P = 0.636) were also not associated with SMA. Moreover, there was no association between genotypes of TLR-4 (8489G /C) [GG (18530), GC (18303) and CC (14952) P= 0.858] or TLR-4 (Asp + 299 Gly) [Asp/Asp (18770), Asp/Gly (37714) and Gly/Gly(67324) P= 0.482] with parasitemia. Similarly, the haplotypes of TLR-4 (G-8984C) + TLR-4 (Asp+299Gly), [G/Asp (P=0.887), C/Asp (P=0.884) and C/Gly (P= 0.4032)] had no association with parasitemia. The results demonstrated that TLR-4 (8489G/C) and TLR-4 (Asp+299 Gly) genotypes and haplotypes are not associated with SMA or parasitemia in the population of interest. The investigation outcomes are important in providing insights on the effect of polymorphism in immune cells in designing novel treatments and vaccinations in the fight against malaria. The study recommends further longitudinal studies to fully understand the functions of the polymorphisms in SMA.Item Properties of Isolated Galaxies within a Redshift Range of 0.005 < Z < 0.080(Kenyatta University, 2024-05) Kalondu, Kinyumu MarcelinaIn the study of galaxy formation and evolution process, a number of processes and properties are known to influence the formation and evolution process such as protogalactic clouds, galaxy masses and galaxy environment. Despite studies done on different environments, the effect of environment on galaxy properties has not been fully quantified. In this study, a sample of isolated galaxies within a redshift of 0.005 < z < 0.080, from the Sloan Digital Sky Survey, data release sixteen, (SDSS-DR 16) was analysed. The aim of the study was to investigate the physical properties of single isolated galaxies in low-density environment, to understand the internal processes and mechanisms dominating galaxy evolution. The classification of galaxies into late-type (mostly spirals) and early-type (mostly ellipticals) in the sample was first done using the central concentration index tool. A Concentration Index, Cr , of 2.65 well classified the sample. The automated classification was later confirmed using visual classifications from the galaxy zoo, were the spiral galaxies dominated the sample of isolated galaxies with about 68%. Through the analysis of colour, magnitude and stellar mass relations, the isolated elliptical galaxies are redder, massive and more luminous, while spiral galaxies seem biased towards the blue, less massive and less luminous side. However, a significantly larger fraction of isolated red spiral galaxies with larger stellar masses and highly luminous was observed. A slightly different distribution by both the isolated blue elliptical and spiral galaxies, characterised by lower stellar masses at lower luminosity was also noted. With the tight correlation of the (u − r) and (r − z) colours, the galaxy sample was analysed as star-formation, quiescent with a fraction of recently quenched elliptical galaxies (RQE). Most of the elliptical galaxies were well selected as quiescent, with majority of the spirals being star forming. This was expected since most elliptical galaxies are thought to be older and have quenched their star-formation, while the spirals are younger and have star forming activities. 5% of the isolated elliptical galaxies seem to have recently quenched their star formation and are transiting to the red sequence, with 90% being blue. The red recently quenched elliptical galaxies are among the 20% low-mass red elliptical galaxies, confirming that most massive elliptical galaxies quenched their star formation long ago. The Hα luminosity star formation rates were derived and correlated with the galaxy morphology and stellar masses. From the analysis, spiral galaxies have higher star formation rates, indicating strong star formation activities, while elliptical galaxies dominate the passive region. An indicated fraction of passively evolving high-mass spiral galaxies and actively star-forming elliptical galaxies was observed. In the emission line diagnostics, 50% of the spiral galaxies had higher star-forming activities, while 54% of the elliptical galaxies dominated in the Active Galactic Nuclear (AGN) powered region. A number of galaxies, both spirals and ellipticals are in transition from star-forming to AGN and occupy the composite region. The star forming galaxies selected in the colour - colour analysis tightly follows the star formation sequence, with 47% having star forming emissions and only 18% have AGN emissions. Recommendations for future work includes, a detailed study on the effect of galaxy properties on the central concentration index morphological classification tool, and further investigation on the powering mechanism of isolated galaxies with other methods.Item Harnessing the Potential of Phosphate Solubilizing Bacteria for Improvement of Maize and Cowpea Production in Semi-Arid Agro-Ecosystems of Eastern Kenya(Kenyatta University, 2023-05) Kibet, Charles Kirui; Ezekiel Mugendi Njeru; Stephen RunoAbstractItem Evaluation of Sex Selection Activity and Safety of Vernonia Amygdalina (Del), Rubia Cordifolia (Linn), and Asparagus Racemosus (Willd), in Rats(Kenyatta University, 2023-01) Wambugu, Enoc Njoroge; Eliud NM Njagi; John K MwonjoriaAbstractItem Cognitive Enhancing Effects of Aqueous Extracts of Amaranthus dubius Mart. Ex Thell and Vigna unguiculata (L.) Walp. in Mice(Kenyatta University, 2023-02) Kipkemoi, Daisy Jepkosgei; Mathew Piero Ngugi; Antony IreriAbstractItem Antibacterial Antioxidant, Phytochemical Profile and Toxicological Efffects of Aqueous extract of Rhaphiolepis Bibas (Lour.)(Kenyatta University, 2023-05) Kariuki Ibrahim WaweruAbstractItem In Vivo Anxiolytic and Teratogenic Effects of the Aqueous Extracts of Carissa Spinarum and Azadirachta Indica(Kenyatta University, 2023-10) Wabai, Yvonne Wairimu; John K. Mwonjoria; Joseph J. N. NgeranwaAbstractsItem Phytochemical Composition, in Vitro Antmicrobial Activity, And Cytotoxicity of Essential Oils of Ocinum Gratissimum, Ocimum Kilimandscharicum and Lippia Javanica(Kenyatta University, 2023-04) Samoei, Chemutai Judith; Mathew Piero Ngugi; Christine BiiAbstractItem Evaluating the Therapeutic Potential of Bacteriophages against Multidrug Resistant Pseudomonas Aeruginosa Clinical Isolate in Balb/C Mice(Kenyatta University, 2023-06) Omwega, Meshack Tweya; John Maingi; Anthony Kebira; Atunga NyachieoAbstractItem Prediction of Protein-Protein Interactions Between Striga (Striga Hermonthica (Del.,) Benth) and Sorghum (Sorghum Bicolor (L.) Moench)(Kenyatta University, 2023-10) Muganda, Osbourne Waswa; Omwenga, George I.; Njgngal, Peter K.AbstractItem In vitro Synchronization and Conversation of Somantic Embryos of coffea Arabica L.F, Hybrid(Ruiru) in Kenya(Kenyatta University, 2023-10) waswa, Muganda Osbourne; George I. Omwenga; Peter K.NjengaItem Prediction of protein protein interaction between STRIGA (Striga hermonthica (DEL.) BENTH) AND SORGHUM (Sorghum bicolor (L.) MOENCH)(Kenyatta University, 2023-10) Chabari, Benson M; Steven M Runo and Mark WamalwaABSTRACT Plants constantly face myriad of threats from phytopathogenic fungi, bacteria and the notorious parasitic plants, Striga spp. When attacked, host plants invoke two tier of immunity, PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI). Striga hermonthica, obligate hemiparasitic plants, are one of the most devastating biotic stresses that constrain food production. In SSA, S. hermonthica causes enormous losses due to its broad host range and huge soil seedbank, threatening the food basket of the continent. The molecular dialogue between Striga-sorghum interactions remains poorly understood. Like phytopathogens, S. hermonthica secretes small-cysteine rich effector proteins that target subdue host innate immunity. This study evaluated the effector proteins secreted by S. hermonthica using various bioinformatics tools. Further, the study explored the role of the Striga effectors in Striga-sorghum protein- protein interactions. Striga-sorghum protein-protein interactions prediction was accomplished by two computational methods, namely interolog and domain-domain interaction methods. The study reports S. hermonthica classical secretome of 741 (1.28%) consisting of 521 secreted putative effector proteins. Protein-protein interaction predictions identified 379 PPIs between sorghum and S. hermonthica, comprised of the 95 Striga virulent factors and 174 sorghum (Sorghum bicolor) proteins. Among the 95 Striga virulent factors, 32 were preferentially expressed in planta during Striga haustorium-host root vasculature connection. The findings showed that the parasitic Striga deployed various virulent factors include alkalinizing agents (RALF), cell wall degrading enzymes (PMES, PAES and XETH) and acid phosphate to interact with the host. Functional analysis revealed that Striga effectors target essential host processes, including protein synthesis, transport, and degradation, signal transduction, and metabolic pathways. The study also identified host resistance. elements, such as RPM1, RPS2, FLS2, and PBS1, along with the susceptibility gene FER, as targets of Striga virulent factors. These interactions disrupt host defense- related signal transduction cascades, weakening the host's ability to mount an effective defense. In conclusion, the findings from this study provides valuable insights into the molecular mechanisms of Striga pathogenesis and host defense strategies. The findings suggest that Striga effectors play a pivotal role in promoting disease progression by targeting key host immune proteins. Understanding the host-Striga interactions can inform the development of novel strategies to enhance crop resistance against parasitic plants like Striga. Future research should focus on experimental validation of these interactions and explore genome editing technologies to improve host resistance.Item Determination of the Most Sensitive and Specific Electrolytes Deltacheck Method for Quality Control in the Nairobi Hospital Laboratory, Kenya(2023-11) Kiarie, Tom; Marion Warigia Burugu; Angela AmayoAbstractItem Molecular characterisation of FLOUROCOINE NON Ssuspectible Anteric Bacteria tio from children under five years from Kisii and Homeabay Referal Hospitals in Kenya(Kenyatta University, 2023-11) Kariuki, Kevin M; sUSAN Misimbio and Simon KariukiItem Magnitude and Geographical Distribution of Nontuberculous Mycobacteria Species among Presumptive Pulmonary Tuberculosis Patients in Selected Sites in Kenya(Kenyatta University, 2023-09) Aberi, Ruth Moraa; Anthony Kebira; Willie GithuiAbstractItem Assessment of Tritrophic Interaction between Larval Parasitoid, Cotesia Icipe (Hymenoptera: Braconidae) and Its Key Hosts in Maize Cropping Systems In Kenya(kenyatta university, 2023) Obala, Francis; Samira Mohamed; Subramanian Sevgan; Titus Obidi MagomereThe introduction and establishment of fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), cause devastating damages to maize crops and major loss to the source of income for millions of maize growers in Africa. Farmers responded to the pest through application of broad-spectrum insecticides, which are not only expensive and face problems of pest resistance, but also pose negative effect to the environment, human health, and kill beneficial insects. Biological control offers safer and sustainable management option against fall armyworm. With the proof that Cotesia icipe (Hymenoptera: Braconidae) was a potential biocontrol agent, there was a research gap on the efficiency of the parasitoid to manage the target pest within maize cropping system in Kenya. Thus, this thesis investigated the tritrophic interactions, involving plants, herbivores, and the natural enemy (parasitoid). To achieve that objective, first, the host range and performance of C. icipe on the target pest, S. frugiperda, and potential hosts, Busseola fusca, Chilo partellus (Swinhoe), Sesamia calamistis Hampson, and Spodoptera littoralis (Boisduval, 1833) (all Lepidoptera: Noctuidae). Second, the parasitism of S. frugiperda by C. icipe reared on different host plants and the effects of the host plants on the quality of the parasitoid progenies was assessed. Third, the behavioural response of C. icipe, in terms of its oviposition choices to maize plants infested by the stemborers and S. frugiperda was also assessed. Lastly, the chemical analysis of organic volatile profile emitted by maize plants due to herbivory by the stemborers and S. frugiperda, as well as the antennal responses of S. frugiperda female moths to the compounds, were also evaluated. The acceptability of the stemborers and Spodoptera species to C. icipe was conducted under no-choice test, whereas its performance on each host, in the presence of all hosts, was done under multiple-choice test. In addition, suitability of the host insects for the development of the parasitoid, and effects of each host larvae on the development and fitness of the parasitoid progenies were evaluated. To test the parasitism and development of C. icipe when it develops in S. frugiperda larvae reared on the different host plants (commonly intercropped with maize), then cocoon formation rate, sex ratio, and fitness of the parasitoid progenies were evaluated. Further, in a Y-tube olfactometer, the response of C. icipe towards stemborers and S. frugiperda- infested maize plants was tested in terms of the parasitoid choices to the chemical cues. Lastly, Gas Chromatography (GC) Mass Spectrometry and GC- electroantennographic detection were conducted on the volatile organic compounds that were extracted from damaged (by stemborers and S. frugiperda) and healthy maize plants on S. frugiperda female moths. The results showed that C. icipe deposited its eggs and successfully developed in all the stemborers and Spodoptera species, albeit with differences in developmental duration, being longest in C. partellus (19.0 ± 0.4 days from egg to cocoon formation), but not significantly different for the duration between cocoon formation and wasp eclosion (4 days) for all the tested hosts. Under no choice test, C. icipe parasitized and successfully completed its life cycle in all the tested hosts; with the highest parasitism recorded in both Spodoptera species (97%) and the least parasitism obtained in C. partellus (24%). In multiple-choice test scenario, highest parasitism was recorded in both S. frugiperda (97%) while the least parasitism was obtained in C. partellus (24%). Moreover, the assessment of encapsulation or melanisation revealed that only 0.05% of C. icipe eggs were encapsulated by C. partellus. For the analysis of the plant odours commonly reported compounds such as linalool, (E)-α-Bergamotene, TMTT, β-caryophyllene, DMNT, (Z)-3-hexen-1-ol, indole and (Z)-3-hexenyl acetate were obtained. Importantly, those compounds elicited antennal response of S. frugiperda females. In conclusion, this study found that using C. icipe in augmentative biocontrol of S. frugiperda in maize cropping system in Kenya is not jeopardized by the co- occurrence of the stemborers with the Spodoptera species, and neither the volatile organic compounds emitted by maize plants nor the existence of different host plants of S. frugiperda affect the parasitoid’s efficiency towards fall armyworm as the target pest.