Masters Theses:Department of Biological Sciences

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Anti-Cancer and Anti-Inflammatory Secondary Metabolites of Fagaropsis Angolensis (Engl.) H.M. Gardner
(University of Embu, 2020-12-11) Wambua, Mukavi Justus
Cancer has become a key public health affliction worldwide. Recent studies have shown that genetic factors cause only 5–10% of all human cancers, while the rest are caused by lifestyle. Epidemiological and clinical studies have shown that chronic inflammatory diseases predispose individuals to various types of cancer. An estimated 20 % of all cancer related deaths globally arise from primary infections and inflammation. Current treatments for cancer include radiotherapy, chemotherapy, surgery, hormone, immune and targeted therapies. However, the efficacy of these treatments is constrained by their unexpected detrimental effects on other non-target tissues, development of multi-drug resistant cancer cell lines and high cost. Medicinal plants are increasingly attracting attention of researchers as a source of complementary and alternative therapies to mitigate cancer morbidity and mortality. Plants have been reported to contain bioactive phytochemicals with anti-infective properties against chronic diseases, including inflammation and cancer. In the current study the air-dried roots bark and leaves of Fagaropsis angolensis were pulverized into fine powders. The plant materials were then exhaustively extracted with 50% CH3OH in CH2Cl2 (v/v) at room temperature by cold solvent percolation. Separation was carried out using column chromatography on silica gel as the stationary matrix and eluted with gradients of n-hexane, EtOAc and MeOH. The resultant fractions were then purified using finer silica gel by recurrent column chromatography, Sephadex LH 20 and Chromatotron to afford a total of five compounds including two new norhopane derivatives; 3β,6β,22-trihydroxy-7β,11α-di[(4-hydroxybenzoyl)oxy]21αH-24-norhopa-4(23)-ene (42) and 3β,6β,22-trihydroxy-7β-[(4- hydroxybenzoyl)oxy]-21αH-24-norhopa-4(23)-ene (43) together with the known norhopane, 3β,6β,11α-trihydroxy-7β-[(4-hydroxybenzoyl)oxy]-24-norhopa- 4(23),17(21)-diene (44) and a norneohopane, (21α-H)-24-norneohopa-4(23), 22(29)diene-3β,6β,7β-triol 7-caffeate (30) from the root bark. The leaves afforded a reported flavone, tachrosin (45). Their structure elucidation was achieved by detailed 1D and 2D NMR, HRESI-MS, FT-IR and UV spectra for the newly described compounds and by comparison of these data with those of correlated compounds in the published literature. Resazurin reduction assay was used to evaluate the cytotoxicity of compound 46, with doxorubicin as reference anticancer drug. Compound 46 displayed minimal activity since the cell viability was more than 70 % against drug sensitive CCRF-CEM. Owing to the risk associated with chronic inflammation to initiation, promotion and progression of carcinogenesis, compounds 42 – 45 were assessed for their anti-inflammatory activity by quantifying the levels of cytokines Interleukin-1β (IL-1β), Interleukin-2 (IL-2), Granulocyte-macrophage colony-stimulating factor (GM-CSF) and Tumor necrosis factor-alpha (TNF-α) in lipopolysaccharide (LPS) stimulated peripheral blood mononuclear cells (PBMCs). All tested compounds decreased secretion of IL-1β and TNF-α. Compounds 43 and 45 clearly decreased secretion of IL-2, GM-CSF and TNF-α in comparison with the reference drug ibuprofen. The findings from this study revealed that F. angolensis contains significant amounts of hopane-type triterpenoid derivatives with potential to downregulate pro-inflammatory biomarkers and further provide a scientific rationale for using the plant in Kenyan folk medicine as anti-pain solution.
Bacterial biological control agents in the management of bacterial wilt(curtobacterium Flaccumfaciens PV.Flaccumfaciens) in the common bean
(UoEm, 2023-08) Munene, Lilian Wangui
Common beans (Phaseolus vulgaris) are widely grown throughout the world and provide valuable protein, vitamins and other nutrients. If the challenges related to its production are resolved, food security can be guaranteed for the growing population. Disease-causing pathogens are a major constraint in bean production. Curtobacterium flaccumfaciens pv. flaccumfaciens causes bacterial wilt of common bean disease. This pathogen causes high economic losses due to seedling death, yield loss and seed discoloration. Copper fungicides can reduce secondary spread but are expensive, harmful to the environment and lead to resistance of the pathogen. Bacterial control agents are effective and environmentally friendly alternatives to chemicals, as they provide protection throughout the crop period and are specific to plant diseases. However, less has been done in managing bacterial wilt using bacterial bio-controls. The objectives of this study were; to isolate wilt-causing pathogen in dry beans, to isolate bacterial antagonists against the pathogen from the rhizosphere of P. vulgaris and to control the pathogen in vitro and in vivo using the recovered bacterial bio-controls. The study was done in an experimental bean field located in Kimbimbi, Kirinyaga County. From infected leaves and seeds of bean plants, Curtobacterium species were isolated and characterized morphologically, biochemically, molecularly and by pathogenicity tests. Biological control agents were identified in the soil samples obtained from the rhizospheres of bean plants and screened against Curtobacterium flaccumfaciens using soft agar overlay assay. Primer pair 8F and 1492R were used for amplification of the 16S rRNA gene and sequencing. Analysis of the 16S rRNA gene was conducted to identify the Cff isolates and bacterial antagonists. Both a foliar spray and a seed treatment were used to apply bio-controls. A completely randomized design was employed for the experiment. Data on disease incidence and disease severity were analyzed using analysis of variance at a 95% confidence level. Phylogenetic analysis was done using the neighbor-joining method and phylogenetic tree constructed with MEGA software. Eleven Curtobacterium spp. were identified. Nine bacterial control agents showed antagonistic activities against Cff. A partial 16S rRNA gene sequence of these isolates identified species belonging to the genera Bacillus, Paenibacillus and Pseudomonas. Seed treatment coupled with foliar application of the antagonistic bacteria significantly reduced disease incidence and disease severity ranging from 16-29% and 4-10% respectively, compared to the control. Pseudomonas fluorescens was most successful in controlling the Cff pathogen with an efficacy of 81%, while B. cereus and P. polymyxa reduced the disease development by 79% and 68%, respectively. The use of rhizobacterial species provides a safe, effective and sustainable alternative to control bacterial wilt in the common bean. Herein, the rhizobacteria P. fluorescens, B. cereus and P. polymyxa species seed treatment coupled with foliar application significantly reduced the disease incidence and disease severity of bean bacterial wilt. The study recommends further research on distribution of bacterial wilt of common bean disease in bean-producing regions of Kenya and to determine if the isolated bacterial control agents are effective against other plant diseases
Bacterial Food Contaminants in Vended Fast Foods, Soil and Water in Embu Town, Kenya
(SUSAN WAIRIMU MURIUKI, 2020-11) Muriuki, Susan Wairimu
Ready to eat fast food vending business has grown exponentially however, the microbiological safety of most of these fast foods is questionable. Despite the cholera outbreak in Embu in 2017, diminutive information exists on waterborne and foodborne illness outbreaks resulting from bacterial pathogens in Embu Town and the nearby Kangaru Market. Thus this study aimed to isolate and characterize bacterial food contaminants in the vended fast foods and their surrounding environment in Embu Town and nearby Kangaru Market. Bacterial isolates were isolated from; fried fish, African sausages, roasted meat, samosa, fries, vegetable salads, soil and water. Antibiotic susceptibility testing was done using the Kirby-Bauer method. DNA was extracted from pure isolates using the phenol-chloroform method. The 16S rRNA and resistant genes were amplified with the respective primers. Taxonomy was assigned to each Operational Taxonomic Units using BLAST. Sequence alignment and construction of the phylogenetic tree were done using MEGA X. Total community DNA was extracted from samples using the phenol-chloroform method. The 16S rRNA gene variable region (V4-V7) of the extracted DNA was amplified and library construction was performed according to Illumina sequencing protocol. Sequence analysis was done using QIIME2 while Analysis of similarity (ANOSIM) test, based upon Bray-Curtis distance, Non-metric Multidimensional Scaling (NMDS), redundancy analysis (RDA) as well as Hierarchical clustering of the samples, were carried out using the R programming language. Taxonomic groups were derived from the number of reads assigned to each taxon at all ranks from domain to species using the taxa summary.txt output from the QIIME2 pipeline. Antibiotic resistance of the isolates was; chloramphenicol 90%, cefotaxime 84.29%, nalidixic acid 81.43%, tetracycline 77.14%, amoxicillin 72.86%, gentamycin 48.57%, streptomycin 32.86% and trimethoprim + sulphamethoxazole 30%. Isolate KMP337, exhibited significantly high antibiosis against S. aureus recording an average inhibition of diameter mean and standard error (SE)16.33±0.88mm respectively at P = 0.001. Polymerase chain reaction detected the presence of resistance genes; tet (A), bla TEM, strB, dfr (1), bla Amp, and Flor genes. The isolates clustered in five main genera namely Bacillus, Paraclostridium, Lysinibacillus, Virgibacillus, and Serratia all having similarity of above 90%. The OTUs were distributed among twenty-three bacterial phyla across the samples with the most abundant belonging to Proteobacteria (52.81%), Firmicutes (31.16%), Bacteroidetes (8.00%) and Lentisphaerae (0.001%). The OTUs were shared among archaea as follows; Candidatus nitrososphaera (83.89%) and Nitrososphaera (11.43%). Lactobacillus perolens, Pseudomonas spp., Clostridium spp., and Bacillus cereus were detected in abundance across the samples. Potential pathogens in risk group 2 including Rickettsia spp. and Brucella spp., Coxiella spp. in risk group 3 were detected. Uncultured Candidatus koribacter sp, Candidatus microthrix sp. and Candidatus solibacter sp. were detected in food. This study confirmed the presence of antibiotic-resistant foodborne potential pathogens in vended fast foods and the soil in Embu Town and Kangaru Market. The study, therefore calls for continuous monitoring of bacterial status and hygienic handling of vended foods. The detection of potential pathogens calls for stringent hygiene measures in food vending operations, especially in Kangaru Market.
Bioprospecting for Cyanophages with Biocontrol Potential against Toxin Producing Cyanobacteria in Lake Magadi, Kenya
(University of Embu, 2020-11) Kihagi Ngetha, Edwin
Cyanobacteria are a phylum of blue-green algae in the domain bacteria that get their energy from sun light through photosynthesis. In anaerobic environments, photoautotrophic blue green algae derive electrons by reduction of sulphur. In the Kenyan soda lakes, cyanobacteria serve as the sole source of food for Lesser Flamingos. Also, detection of these blue green algae blooms, is evident in these environments. Due to this reason, it has been hypothesized that the blooms may lead to production of secondary metabolites referred to as cyanotoxins that could be the cause for mass mortalities of Lesser Flamingos in these lakes including Lake Magadi. Viruses are key in controlling microbial populations in any ecosystem and thus they could act as a biocontrol measure for toxin producing cyanobacteria. Therefore, this study aimed to isolate cyanobacteria, amplify for toxin production genes and screen for cyanophages that can control these toxin producing cyanobacteria. The study site was Lake Magadi in the Rift Valley which has highly alkaline pH (8-12). Water samples were collected from different points around Lake Magadi. Physiochemical variables such as pH, salinity and temperature were measured for each of the sample on site. Two techniques for the isolation of cyanobacteria were used: isolation by spread plating on agar and dilution to extinction technique. Five types of media were used: Blue green medium (BG11), Synechococcus medium (A+), artificial lake water medium (ALW), artificial sea water medium (ASW) and enriched lake water medium (M). For solid cultures, spread plating was done followed by subsequent sub-culturing to acquire axenic cultures. Dilution to extinction technique involved subsequent dilution of the enriched sample until an axenic culture was obtained. These isolates grew at conditions that are unique to haloalkaliphiles. The cyanobacteria were subjected to morphological and molecular identification. Molecular identification involved partial sequencing of 16Sr RNA gene. Potential of the isolates to produce cyanotoxins was assessed by amplification of their respective genes using toxin specific primers. Sequence analysis indicated that all 11 isolates were affiliated to Cyanobacterium Spp. Genera represented include Spirulina, Synechococcus, Oscillatoria and Anabaenopsis. PCR amplification showed that all the isolates had different genes for toxin production. Phage lysis was observed in 10 of the isolates indicating that they were hosts for the phages. This study provides an insight into the uncultured cyanobacterial species from extreme environments and their cyanophages. The recovered isolates are a useful resource in understanding the taxonomy, phylogeny and diversity of cyanobacteria as well as their cyanophages. The cyanophages can be useful in biotechnology application for biocontrol of toxin producing cyanophages.
Competence of Tropical Maize Lines to Agrobacterium-Mediated Transformation and the Expression of Maize Poly (ADP-Ribose) Polymerase (PARP2) Gene under Drought Stress.
(Kenyatta University, 2017) Muli, Joshua K.
Drought stress affects many maize growing regions in sub-Saharan Africa. As population increases, the gap between maize supply and demand increases. There is, therefore, need to develop maize lines that are tolerant to drought as well as amiable to Agrobacterium-mediated transformation. This study aimed to assess the competence of tropical maize lines after co-cultivation on Yeats Extract Peptone (YEP) media to Agrobacterium-mediated transformation and determine the relative expression of PARP2 gene under drought during development. Tropical inbred maize lines CML 144, CML 216, A04, and E04 as well as Agrobacterium strain EHA101 harboring vector pTF102 containing the GUS reporter gene were used in this study. The ability of immature maize embryos to form embryogenic calli was determined after pre-culturing these embryos on YEP and Murashige and Skoog (MS) media. Transient GUS assay was used to evaluate the competence of the inbred maize lines to Agrobacterium-mediated transformation using YEP as co-cultivation media or YEP that was supplemented with growth regulator 2,4-D (YEP+2,4-D), Cysteine (YEP+CYS), Proline (YEP+PRO) or in combination (YEP+ALL). In all cases, MS media was used as the control. The optimum Agrobacterium concentration for infection of immature maize embryos before co-cultivation was determined. The physiological response of tropical maize lines to drought stress was evaluated and the expression of the PARP2 gene at different drought levels determined by Polymerase chain reaction (PCR). The data collected was analysed using ANOVA at 95% confidence interval with SAS statistical computer software (version 9.1.3). Separation of means was carried out using Tukey’s pairwise comparison at 5% probability level. Callus formation frequency and regeneration were genotype dependent (P= 0.0001). Immature embryos from the four inbred maize lines exhibited high transient GUS expression when co-cultivated with Agrobacterium on YEP (12.31%), YEP+PRO (13.75%) and YEP+ALL (8.68%) media than when cocultivated on MS media (6.76%). Co cultivation in YEP+2,4-D and YEP+CYS, however, resulted in lower transient GUS expression than on MS media. Agrobacterium tumefaciens at a concentration of 0.07 (OD660) gave the highest transient GUS expression (20.90%) while higher concentrations of 0.2 and 0.8 resulted in low transient GUS expression (9.17% and 12.22%), suggesting that YEP media is superior to MS media in enhancing the competence of immature embryos to Agrobacterium-mediated transformation. Thus YEP media is proposed as an alternative media in in Agrobacterium-mediated transformation protocols. Growth rate, fresh weights of seedlings and dry weights of seedlings was low in seedlings subjected to severe drought stress compared to seedlings subjected to moderate drought and unstressed conditions. Severe and moderate drought stresses induced the expression of maize PARP2 gene, suggesting that deregulation of maize PARP2 gene is likely to improve the ability of tropical maize to resist severe drought stress condition.
Cover Change and Vegetation Carbon Stocks of Mangrove Forests in Lamu County, Kenya
(UoEm, 2023-04) Mbatha, Anthony Mutua
Mangroves around the world are being threatened by a combination of natural and human factors. Losses of mangroves leads to reduced forest cover and enhanced carbon emission. This study assessed cover change, forest structure, natural regeneration, and carbon stocks of mangroves in Lamu County, Kenya. Landsat images were used to assess cover change from 1990 to 2019, and structural data were obtained in the field using the plot method. Using stratified random design, mangroves were sampled in 152 square plots of 400 m2 along belt transects established perpendicular to the waterline. Within each plot, all trees with stem diameters ≥ 2.5 cm were identified, counted and position marked, while those < 2.5 cm were counted and classified as juveniles. The following parameters were recorded: tree height (m), stem diameter (cm), and canopy cover (%); from which stem density (stems ha-1), basal area (m2 ha-1), volume (m3 ha-1), and biomass (t ha-1) were enumerated. Six mangrove species were encountered during this study. Based on importance value index, the dominant mangrove species in Lamu were Rhizophora mucronata (Lam.) and Ceriops tagal (perr.) C.B. Rob., that accounted for more than 70% of the mangrove formations. Mean standing density of the mangroves was estimated at 2,339±241 stems ha-1 (range:1,607-3,092 stems ha-1), with a basal area of 24.26±3.18 m2 ha-1, and volume of 157.97±15.22 m3 ha-1. At least 42% of the forest was stocked with low-quality poles, indicating prolonged human pressure. However, natural regeneration rate of 7,342±450 juveniles ha-1 observed in the forest was considered adequate to support forest recovery following disturbance. The mean biomass was estimated at 354.98±49.81 Mg ha-1. This translates to vegetation carbon storage of 166.56±23.41 Mg C ha-1. Mangroves in Lamu were estimated at 35,678 ha, representing 62% of the country’s total. Approximately, 1,739 ha of mangroves were lost between 1990 and 2019, mainly due to anthropogenic activities, representing a decline of 60 ha yr-1. Total emission from loss and degradation of mangrove vegetation in Lamu was estimated at 41.64 Mg C ha-1; which translates to 9,169.13 Mg CO2e yr-1. Assuming an offset price of US$10/Mg CO2e, the estimated cost of avoided emissions in Lamu County is US$91,691.3 yr-1 plus other co-benefits such as fishery support and shoreline protection. Mainstreaming mangroves and associated blue carbon ecosystems into national development and climate change agendas could accelerate Kenya’s achievements to the Paris Agreement and other processes.
Cytokine Levels and T cell Apoptosis Associated With Cerebral Malaria Immunopathology During Plasmodium berghei Anka Infection In A Mouse Model
(2013) Mugweru, Julius
During the course of malaria infection, a range of pro- and anti-inflammatory cytokines are produced by the host immune system. Successful recovery from malaria involves striking a balance between these counteracting cytokines. The cytokine imbalance contributes to pathological features but their exact levels have not been elucidated. The present study aimed at investigating the role played by circulating cytokines in pathophysiology of cerebral malaria. Using an experimental cerebral malaria (ECM) model, the profile of five serum cytokines was determined by employing Cytometric Bead Assay. Seventy-two BALB/c mice (7-9 week/old) were intraperitoneally inoculated with approximately 1 x 105 parasitisized red blood cells at day 0 and randomized into six groups (six mice/group). Another set of noninfected mice was included to serve as control. The mice were sacrificed at day 4, 6, 8, 11 and 20 pi. The possible role of cytokines in inducing T-cell apoptosis associated with CM was investigated using the whole genomic DNA extracted from splenic and brain lymphocytes. Significantly higher systemic levels (P<0.05,) of IFN-γ (mean ±S.D 210.6±133, 169.8±80.5, 203.6±91.6, 22.0±3.5 pg/ml), were observed between day 8 and 20 p.i while TNF-α levels were significant at days 4, 8 11, 14 and 20 respectively (M ±S.D 2.9 ± 0.2, 33.9±17.5, 95.5 ±17.0, 22.1±3.6 pg/ml) in BALB/c mice that survived until day 20 pi with a higher parasitemia (up to 52.6%±0.8). Significant concentrations (P< 0.05), of IL-4 (M ±S.D 14.6±2.5, 10.6±1.9, 9.6±1.3 pg/ml) were observed between day 4 and 8 respectively but afterwards its levels remained low throughout the course of infection. IL-5 levels (M xix ±S.D 4.1±0.7, 3.4±1.6) had significant differences at day 11 and 20 pi. The study found IL-4 to be elevated between days 11 and 20 respectively with no significant differences (P>0.05) being reported. T-cell pathology was revealed by fragmentation of whole genomic DNA during the infection which coincided with elevated systemic pro-inflammatory (IFN-γ and TNF-α at day six) responses which further accelerated the severity of CM. The study demonstrated a parallel link between T-cell pathology and elevated levels of Th1 cytokines concentrations in the brain and the spleen. This study revealed that elevated levels of proinflammatory cytokines induce inflammation and cellular apoptosis inhibiting parasite clearance. Thus, interventions to regulate the Th1 cytokine responses may be beneficial in the prevention of severe CM. Further work is needed on IL-2 IL-10 and IL-12 cytokines that could be involved in the pathology
Diversity and Biological Control Potential of Haloalkaliphilic Fungi from Lake Magadi, Kenya
(University of Embu, 2020-12-11) Orwa, Philemon
Fungi are eukaryotic microorganisms that have simple multicellular or unicellular cell structures. They are distributed in terrestrial soils, forests, aquatic habitats and in extreme environments with high ambient salts, temperature, pH and pressure. Fungi from extreme environments are potential sources of novel biocatalysts for example antimicrobial agents that can help solve the rising cases of drug resistance. However, the diversity of fungi recovered and described from less studied environments such as the soda lakes is quite low as compared to the soil ecosystem. Very few haloalkaliphic fungi have been recovered from hypersaline environments. In this study, we explored the cultivable fungal diversity in Lake Magadi and their ability to produce secondary metabolites. Dilution plate technique was used to isolate fungi from soda lake soils using alkaline media (Potato dextrose agar, Malt extract agar, Oatmeal agar and Sabouraud dextrose agar) prepared using sterilized lake water from the lake. Unique isolates were selected based on morphological features and subjected to physiological tests to determine their ability to grow at different pH, temperature and salts ranges. Molecular characterization was done by analysis (BLAST) of the amplified conserved regions of 18SrDNA followed by phylogeny. Ability of the isolates to utilize different carbon sources was tested on media supplemented with different substrates (starch, cellulose, casein, lignin, pectin, xanthan, chitin, Tween 20). Antimicrobial screening was done using both crude and cell free extracts to determine the ability of the isolates to produce metabolites (comparison of mean diameter of inhibition zones) that can be used to control both human pathogens and agricultural pathogens. The test pathogens included human pathogens Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Salmonella spp., Shigella spp. and Candida albicans which were laboratory isolates and plant pathogens Epicoccum sorghinum strain JME-11, Alternaria tenuissima, Didymella glomerata, Schizophyllum commune isolate ScGD28, Phoma destructiva, Cladosporium halotolerans CBS 119416, Aspergillus fumigatus EG11-4 and Dickeya dianthicola (field isolates). In total, 52 isolates were recovered from the study having different pigmentations. Their physiology depicted actual characteristic of haloalkaliphilic environments as the fungi tolerated extreme pH of up to 10 and salts (15-20%) and some grew at 35-40ºC. Sequence analysis indicated that the isolates were affiliated to 18 different genera with Aspergillus, Penicillium, Phoma, Cladosporium, and Acremonium. Substrate utilization tests showed that the different isolates produced proteases, chitinases, cellulases, amylases, pectinases and lipases. Isolates 2M, 59M, 69M, 87M, 100M, 111M and 113M were outstanding as they produced more than four enzymes. Results from the antimicrobial screening showed one isolate (11M from Site 3 soil) with 99% affiliation to Penicillium chrysogenum CBS 306.48 was able to inhibit major enteric bacteria and plant pathogenic fungi. Similar studies on saline environments have reported the phylum Ascomycota as the dominant fungal group and all the genera recovered in this study are classified in the same phylum. Antimicrobial from the fungal isolates provide a basis for pharmacological research since they can further be purified to obtain compounds that can be used as antibiotics or biopesticide against human and plant pathogens respectively. This can provide a solution to the rising problem of antibiotic resistance and pesticide resistance.
Drought Prevalence in the Horn of Africa and Its Implications on Forest Cover: A Case Study Of Somalia
(University of Embu, 2020-12-11) Kipngeno, Sylus Musei
Somalia is one of the most drought prone countries in Africa. Drought is the country’s costliest natural disaster. The impact of drought events on the economy, on people`s livelihoods and on lives has grown. Drought events usually develop gradually unnoticed, causing tremendous effects on both agriculture and environment. This study evaluated the spatio-temporal variations of drought occurrences in Somalia and its implication on forest cover. In this study, precipitation and temperature variables were taken as a proxy to assess and quantify long-term drought in Somalia. The intensities, frequencies and trends of drought occurrences were analyzed using Standardized Precipitation Evapotranspiration Index for the multiple timescales of 1-, 3-, 6-, 12-, and 24-month. Drought maps were done using Normalized Difference Vegetation Index during the period 1982 to 2015. Hansen data was used to account for forest cover change whereas a sample of 20 papers were reviewed in order to determine the best fit land degradation mitigation measures. Temporal variations in drought showed decreasing trends in severity and increasing trends in drought duration as the SPEI timescales increased. The major drought event as identified by SPEI 12 occurred during the period between May 2011 and January 2013, lasting for a period of 12months with an intensity of -0.55. Furthermore, drought count was generally high in the southern parts of Somalia and entire country had suffered droughts ranging from moderately dry to severely dry conditions. An average drought duration of between 2 and 3 months was recorded for most (81%) of the locations. About 23 % of forest cover was lost from 79,294 ha to 67,199ha from 2000 to 2019 representing a loss of 1,058ha per year. The study findings show the need for immediate actions to tackle drought and hence poverty and famine in Somalia. A combination of remote sensing tools conservation practices (such as agroforestry, afforestation, reforestation and conservation agriculture) is ideal for monitoring and mitigating land degradation effects respectively.
Drought prevalence in the horn of Africa and its implications on forest cover: a Case Study of Somalia
(University of Embu, 2020-11) Musei Kipngeno, Sylus
Somalia is one of the most drought prone countries in Africa. Drought is the country’s costliest natural disaster. The impact of drought events on the economy, on people`s livelihoods and on lives has grown. Drought events usually develop gradually unnoticed, causing tremendous effects on both agriculture and environment. This study evaluated the spatio-temporal variations of drought occurrences in Somalia and its implication on forest cover. In this study, precipitation and temperature variables were taken as a proxy to assess and quantify long-term drought in Somalia. The intensities, frequencies and trends of drought occurrences were analyzed using Standardized Precipitation Evapotranspiration Index for the multiple timescales of 1-, 3-, 6-, 12-, and 24-month. Drought maps were done using Normalized Difference Vegetation Index during the period 1982 to 2015. Hansen data was used to account for forest cover change whereas a sample of 20 papers were reviewed in order to determine the best fit land degradation mitigation measures. Temporal variations in drought showed decreasing trends in severity and increasing trends in drought duration as the SPEI timescales increased. The major drought event as identified by SPEI 12 occurred during the period between May 2011 and January 2013, lasting for a period of 12months with an intensity of -0.55. Furthermore, drought count was generally high in the southern parts of Somalia and entire country had suffered droughts ranging from moderately dry to severely dry conditions. An average drought duration of between 2 and 3 months was recorded for most (81%) of the locations. About 23 % of forest cover was lost from 79,294 ha to 67,199ha from 2000 to 2019 representing a loss of 1,058ha per year. The study findings show the need for immediate actions to tackle drought and hence poverty and famine in Somalia. A combination of remote sensing tools conservation practices (such as agroforestry, afforestation, reforestation and conservation agriculture) is ideal for monitoring and mitigating land degradation effects respectively.
The Effects of Herbivory on interactions of pollinators and flowers in Acacia SPP. (Fabaceae,mimosoideae) in Laikipia
(Kenyatta University, 2005) Otieno, Mark
Acacia trees are among the most dominant tree species found in semi arid ecosystems with a vast geographical distribution throughout the savanna habitats. The trees are leguminous and have remarkable ability to fix nitrogen in the soil, thereby, improving fertility. About all parts of an Acacia tree are edible to different types of animals and their leaves provide the only greenery in the dry season, so are bound to be eaten. As such, they support enormous pyramids of biomass in complex food chains with super predators at the apex. Economically, they are used as basic sources of fruits, firewood, medicine and secondary products for daily human livelihoods. Owing to their important, a lot of studies have focused on their growth ecology. Herbivory and reproduction are among the most studied aspects of Acacia. However, the interactive link between these two aspects and their effect on the growth success of Acacias is poorly understood. Understanding the link between herbivory and pollination, would not only provide useful information on the interaction of plants and diversity of visitors but also information on the floral morphometry and rewards to pollinators. The general objective of this study was to determine the effects of herbivory on interactions between pollinators and flowers in Acacia spp. The study was conducted at the Mpala Research Centre in Laikipia District of Kenya (0017'N, 36053'E) on one herbivore excluded plot (70m x 50m) and in the open grazed areas adjacent to the excusion plot. Acacia trees for investigation were randomly selected. Data were recorded on floral morphometric measurements and dehiscence in different browsing levels and simulated herbivory plots. The number and type of visitors to the flowers was also recorded besides determining the species diversity of wild flora within the study site. ANOVA was used to analyze variation in different flower attributes, SNKwas used to separate means with significant differences. Generally, unbrowsed trees produed significantly (P<0.05) more flowers, florets, anthers and larger floral diameters than naturally and heavilly browsed Acacia trees. Similarly, unbrowsed trees attracted more pollinators especially bees than naturally browsed trees. An earlier pollinator peak activity was recorded on unbrowsed trees than browsed trees. A significant shist of inflorescence dehiscence time occurred between unbrowsed and naturally browsed trees of A. nilotica, (KS=0.34, P<0.01), A. brevispica (KS=0.34, P<0.01) across the day. The unbrowsed trees attracted significantly more pollinators than naturally browsed trees probably because the unbrowsed trees had larger flowers thereby becoming more visible to pollinators from a distance than those of browsed trees. The delayed floral dehiscence of naturally browsed trees could have been caused by modification of the microclimate around the flowers making them open later in the day than unbrowsed trees. This study has shown than A. nilotica and A. brevispica vary their floral resources greatly when browsed, whereas A. etbaica tends to show compensatory floral growth. More studies therefore, need to be done on their reproductive success.
Epidemiology of urinary schistosomiasis and Soil-transmitted helminthiasis among women of Reproductive age in kwale county, kenya
(Samuel Mutua Ngui, 2024-08)
Schistosomiasis and soil-transmitted helminthiasis (STH) are prevalent infections in Sub-Saharan Africa especially in low-income setting. School aged children have been the main target of preventive chemotherapy in the national school-based deworming program. This study investigated the epidemiology of urinary schistosomiasis and soiltransmitted helminthiasis among women of reproductive age in Mwaluphamba, Kwale County, Kenya. A community-based cross-sectional study design was employed with a systematic random sampling to recruit 422 women of reproductive age (15-49 years) from four villages in Mwaluphamba location. Stool specimens were collected and examined using the Kato Katz method, while filtration technique was used to analyze urine specimens. Participants’ sociodemographic details were obtained using a standardized questionnaire. Statistical analyses were carried out using SPSS version 25, with a significance level set at p≤0.05. The prevalence of urinary schistosomiasis was 4.7% (95% CI 2.8%-6.9%), while the prevalence of soil-transmitted helminthiasis infection was 4.5% (95% CI 2.6%-6.7%). There were no significant differences in the prevalence of urinary schistosomiasis among different age groups (F=4.454, p=0.196), as well as for hookworms (p=0.235) and Trichuris trichiura (p=0.099). Urinary schistosomiasis showed a statistically significant association with haematuria, proteinuria, and leukocyturia. In terms of infection intensities, urinary schistosomiasis ranged from 1 to 120 eggs/10 mL of urine, with a median egg count of 18.45 eggs/10 mL. Patients were diagnosed with light infections of 56.16 eggs/gram and 48.48 eggs/gram for Trichuris trichiura and hookworms, respectively. The study revealed that women without latrines had a 15.70 times higher risk of urinary schistosomiasis compared to those with access to latrines. Additionally, the use of surface water (aOR=1.032, 95% CI 1.023-1.432, p=0.010) and crossing rivers (aOR=1.13, 95% CI 0.290-1.611, p=0.009) were identified as statistically significant risk factors for urinary schistosomiasis. In univariable regression analysis, defecating around water sources (OR=4.34, CI 1.466-12.883) was significantly associated with the prevalence of soil-transmitted helminthiasis (p=0.008). This study provides valuable insights into the prevalence and intensity of urinary schistosomiasis and geohelminths in Mwaluphamba location, which can inform the strengthening of control and elimination programs for these neglected tropical diseases. Based on these findings, it is recommended that comprehensive and sustained intervention strategies be implemented, focusing on improving water, sanitation, and hygiene (WASH) practices, enhancing health education, and ensuring regular mass drug administration (MDA) programs
Food web structure of Nematode communities associated with rice in Mwea, Kenya
(2023-07) Mokuah, DorcasNyaboke
In Kenya, rice is an important staple crop after wheat and maize and the rate of consumption surpasses its production. Apart from consumption, rice is a cash crop for smallholder farmers including those in Kirinyaga County. Despite its usefulness in contributing to food security, rice production has remained low due to various constraints. Among these are plant-parasitic nematodes (PPN) that account for up to 20% of yield losses. Other than the deleterious effect of PPN, rice agroecosystems contain free living nematodes (FLN) that play important ecological roles such as decomposition of organic matter and suppression of destructive PPN. However, through various cropping practices, the diversity and structure of the nematode communities is altered which affects crop productivity. This study examined the abundance and additively partitioned diversity of nematode communitiesin rice in Mwea. Soil samples were collected from 30 rice fields in Nyangati (15) and Tebere (15) in Mwea, Kirinyaga county. Nematode extraction was done using the modified Baermann technique before enumeration and identification to the genus level. To determine the differences in the abundance of nematode genera, one-way analysis of variance (ANOVA) was used. Spatial distribution of nematode communities in Nyangati and Tebere wasexamined using Jaccard index-based non-metric multidimensional scaling.One-way ANOVA was used to evaluate the differences in the indices and metabolic footprints in Nyangati and Tebere. Gamma diversity was additively partitioned into α and β components in the R package vegan.Turnover and nestedness components of beta diversity were computed using the betapart package in R software. The relationship between soil properties and nematode genera was evaluated using canonical correspondence analysis. There were 17 nematode genera in both regions with Aphelenchoides and Longidorus occurring in greater proportions in Tebere.The population of Helicotylenchus was high in Nyangati and Prodorylaimus occurred in high numbers in both regions.Aphelenchoides was positively correlated to electrical conductivity while Helicotylenchus was negatively correlated.The two regions could not be unequivocally ordered due to crossing of the Renyi diversity profiles along the scale parameter.Genus richness partitioning, showed that α and β components contributed 33.7% and 66.3% of the γ diversity, respectively.Partitioning of beta diversity showed that nestedness contributed to the overall nematode diversity observed in Nyangati and Tebere rice fields.Results obtained from this study provide information that could aid in development and implementation of effective and environmentally sound nematode management practices in rice.
Food web structure of Nematode communities associated with rice in Mwea, Kenya
(2023-07) Mokuah, DorcasNyaboke
In Kenya, rice is an important staple crop after wheat and maize and the rate of consumption surpasses its production. Apart from consumption, rice is a cash crop for smallholder farmers including those in Kirinyaga County. Despite its usefulness in contributing to food security, rice production has remained low due to various constraints. Among these are plant-parasitic nematodes (PPN) that account for up to 20% of yield losses. Other than the deleterious effect of PPN, rice agroecosystems contain free living nematodes (FLN) that play important ecological roles such as decomposition of organic matter and suppression of destructive PPN. However, through various cropping practices, the diversity and structure of the nematode communities is altered which affects crop productivity. This study examined the abundance and additively partitioned diversity of nematode communitiesin rice in Mwea. Soil samples were collected from 30 rice fields in Nyangati (15) and Tebere (15) in Mwea, Kirinyaga county. Nematode extraction was done using the modified Baermann technique before enumeration and identification to the genus level. To determine the differences in the abundance of nematode genera, one-way analysis of variance (ANOVA) was used. Spatial distribution of nematode communities in Nyangati and Tebere wasexamined using Jaccard index-based non-metric multidimensional scaling.One-way ANOVA was used to evaluate the differences in the indices and metabolic footprints in Nyangati and Tebere. Gamma diversity was additively partitioned into α and β components in the R package vegan.Turnover and nestedness components of beta diversity were computed using the betapart package in R software. The relationship between soil properties and nematode genera was evaluated using canonical correspondence analysis. There were 17 nematode genera in both regions with Aphelenchoides and Longidorus occurring in greater proportions in Tebere.The population of Helicotylenchus was high in Nyangati and Prodorylaimus occurred in high numbers in both regions.Aphelenchoides was positively correlated to electrical conductivity while Helicotylenchus was negatively correlated.The two regions could not be unequivocally ordered due to crossing of the Renyi diversity profiles along the scale parameter.Genus richness partitioning, showed that α and β components contributed 33.7% and 66.3% of the γ diversity, respectively.Partitioning of beta diversity showed that nestedness contributed to the overall nematode diversity observed in Nyangati and Tebere rice fields.Results obtained from this study provide information that could aid in development and implementation of effective and environmentally sound nematode management practices in rice
Food web structure of Nematode communities associated with rice in Mwea, Kenya
(UoEm, 2023-07) Mokuah, DorcasNyaboke
In Kenya, rice is an important staple crop after wheat and maize and the rate of consumption surpasses its production. Apart from consumption, rice is a cash crop for smallholder farmers including those in Kirinyaga County. Despite its usefulness in contributing to food security, rice production has remained low due to various constraints. Among these are plant-parasitic nematodes (PPN) that account for up to 20% of yield losses. Other than the deleterious effect of PPN, rice agroecosystems contain free living nematodes (FLN) that play important ecological roles such as decomposition of organic matter and suppression of destructive PPN. However, through various cropping practices, the diversity and structure of the nematode communities is altered which affects crop productivity. This study examined the abundance and additively partitioned diversity of nematode communitiesin rice in Mwea. Soil samples were collected from 30 rice fields in Nyangati (15) and Tebere (15) in Mwea, Kirinyaga county. Nematode extraction was done using the modified Baermann technique before enumeration and identification to the genus level. To determine the differences in the abundance of nematode genera, one-way analysis of variance (ANOVA) was used. Spatial distribution of nematode communities in Nyangati and Tebere wasexamined using Jaccard index-based non-metric multidimensional scaling.One-way ANOVA was used to evaluate the differences in the indices and metabolic footprints in Nyangati and Tebere. Gamma diversity was additively partitioned into α and β components in the R package vegan.Turnover and nestedness components of beta diversity were computed using the betapart package in R software. The relationship between soil properties and nematode genera was evaluated using canonical correspondence analysis. There were 17 nematode genera in both regions with Aphelenchoides and Longidorus occurring in greater proportions in Tebere.The population of Helicotylenchus was high in Nyangati and Prodorylaimus occurred in high numbers in both regions.Aphelenchoides was positively correlated to electrical conductivity while Helicotylenchus was negatively correlated.The two regions could not be unequivocally ordered due to crossing of the Renyi diversity profiles along the scale parameter.Genus richness partitioning, showed that α and β components contributed 33.7% and 66.3% of the γ diversity, respectively.Partitioning of beta diversity showed that nestedness contributed to the overall nematode diversity observed in Nyangati and Tebere rice fields.Results obtained from this study provide information that could aid in development and implementation of effective and environmentally sound nematode management practices in rice.
Food web structure of Nematode communities associated with rice in mwea,Kenya.
(UoEm, 2023-07) Mokuah, Dorcas Nyaboke
In Kenya, rice is an important staple crop after wheat and maize and the rate of consumption surpasses its production. Apart from consumption, rice is a cash crop for smallholder farmers including those in Kirinyaga County. Despite its usefulness in contributing to food security, rice production has remained low due to various constraints. Among these are plant-parasitic nematodes (PPN) that account for up to 20% of yield losses. Other than the deleterious effect of PPN, rice agroecosystems contain free living nematodes (FLN) that play important ecological roles such as decomposition of organic matter and suppression of destructive PPN. However, through various cropping practices, the diversity and structure of the nematode communities is altered which affects crop productivity. This study examined the abundance and additively partitioned diversity of nematode communitiesin rice in Mwea. Soil samples were collected from 30 rice fields in Nyangati (15) and Tebere (15) in Mwea, Kirinyaga county. Nematode extraction was done using the modified Baermann technique before enumeration and identification to the genus level. To determine the differences in the abundance of nematode genera, one-way analysis of variance (ANOVA) was used. Spatial distribution of nematode communities in Nyangati and Tebere wasexamined using Jaccard index-based non-metric multidimensional scaling.One-way ANOVA was used to evaluate the differences in the indices and metabolic footprints in Nyangati and Tebere. Gamma diversity was additively partitioned into α and β components in the R package vegan.Turnover and nestedness components of beta diversity were computed using the betapart package in R software. The relationship between soil properties and nematode genera was evaluated using canonical correspondence analysis. There were 17 nematode genera in both regions with Aphelenchoides and Longidorus occurring in greater proportions in Tebere.The population of Helicotylenchus was high in Nyangati and Prodorylaimus occurred in high numbers in both regions.Aphelenchoides was positively correlated to electrical conductivity while Helicotylenchus was negatively correlated.The two regions could not be unequivocally ordered due to crossing of the Renyi diversity profiles along the scale parameter.Genus richness partitioning, showed that α and β components contributed 33.7% and 66.3% of the γ diversity, respectively.Partitioning of beta diversity showed that nestedness contributed to the overall nematode diversity observed in Nyangati and Tebere rice fields.Results obtained from this study provide information that could aid in development and implementation of effective and environmentally sound nematode management practices in rice.
Food web structure of Nematode communities associated with rice in mwea,Kenya.
(UoEm, 2023-07) Mokuah, Dorcas Nyaboke
In Kenya, rice is an important staple crop after wheat and maize and the rate of consumption surpasses its production. Apart from consumption, rice is a cash crop for smallholder farmers including those in Kirinyaga County. Despite its usefulness in contributing to food security, rice production has remained low due to various constraints. Among these are plant-parasitic nematodes (PPN) that account for up to 20% of yield losses. Other than the deleterious effect of PPN, rice agroecosystems contain free living nematodes (FLN) that play important ecological roles such as decomposition of organic matter and suppression of destructive PPN. However, through various cropping practices, the diversity and structure of the nematode communities is altered which affects crop productivity. This study examined the abundance and additively partitioned diversity of nematode communitiesin rice in Mwea. Soil samples were collected from 30 rice fields in Nyangati (15) and Tebere (15) in Mwea, Kirinyaga county. Nematode extraction was done using the modified Baermann technique before enumeration and identification to the genus level. To determine the differences in the abundance of nematode genera, one-way analysis of variance (ANOVA) was used. Spatial distribution of nematode communities in Nyangati and Tebere wasexamined using Jaccard index-based non-metric multidimensional scaling.One-way ANOVA was used to evaluate the differences in the indices and metabolic footprints in Nyangati and Tebere. Gamma diversity was additively partitioned into α and β components in the R package vegan.Turnover and nestedness components of beta diversity were computed using the betapart package in R software. The relationship between soil properties and nematode genera was evaluated using canonical correspondence analysis. There were 17 nematode genera in both regions with Aphelenchoides and Longidorus occurring in greater proportions in Tebere.The population of Helicotylenchus was high in Nyangati and Prodorylaimus occurred in high numbers in both regions.Aphelenchoides was positively correlated to electrical conductivity while Helicotylenchus was negatively correlated.The two regions could not be unequivocally ordered due to crossing of the Renyi diversity profiles along the scale parameter.Genus richness partitioning, showed that α and β components contributed 33.7% and 66.3% of the γ diversity, respectively.Partitioning of beta diversity showed that nestedness contributed to the overall nematode diversity observed in Nyangati and Tebere rice fields.Results obtained from this study provide information that could aid in development and implementation of effective and environmentally sound nematode management practices in rice.
Genetic Diversity and Antigenic Variation of Rabies Viruses from Different Host Species in Eastern and Western Parts of Kenya
(Evalyne Nyambura Wambugu, 2024-08)
Rabies, a viral illness that causes deadly encephalitis, claims over 59,000 lives globally each year, with approximately 2,000 deaths happening in Kenya despite effective countermeasures for both humans and dogs. This study sought to improve the understanding of the genetic differences of the rabies virus (RABV) collected from the brain stem tissues of animals with suspected rabies in two geographic rabies hotspots: Makueni county, in the eastern region, and Siaya county, in western Kenya. Furthermore, the study investigated discrepancies among the antigenic sites of the RABV vaccines currently approved for use in Kenya and the study samples. Between July 2021 and September 2022, 164 brain stem tissues were collected from animals suspected of rabies after testing positive for RABV antigens using rapid diagnostic kits. Subsequently, in the laboratory, the samples were re-screened for rabies ribonucleic acid (RNA) by quantitative Real-Time Reverse-transcription Polymerase Chain Reaction (qRT-PCR) that targets the RABV Large-structural protein gene (L gene). Negative samples by the L gene qRT-PCR were analyzed by conventional PCR that targets the RABV Nucleoprotein gene (N gene). Phylogenetic analysis was carried out using whole genome sequences (WGS), as well as single genes (nucleoprotein (N) and glycoprotein (G). The amino acid changes in the antigenic regions of individual proteins (N and G) in the research sequences were compared to three RABV vaccine sequences: Pitman-Moore L503 (PM), Challenge Virus Standard (CVS), and Pasteur vaccine (PV). The L gene qRT-PCR revealed positive results for 156 of the 164 brain stem tissues. Eight samples failed to amplify the L-gene but amplified by N gene. On sequencing, 141 samples produced sequences suitable for analysis. Phylogenetic analysis using WGS and single genes confirmed that the RABV strains belonged to the Cosmopolitan clade that branched into two distinct phylogeographic subclades: sequences from eastern Kenya predominantly grouped within the Africa 1b subclade with only three sequences in the Africa 1a subclade. Conversely, the sequences from western Kenya formed clusters within the Africa 1a subclade while three were in the 1b subclade. In keeping with this phylogeographic clustering, the western Kenya Africa 1a subclade's closest ancestor was found in Sudan, while the eastern Kenya Africa 1b subclade had its origin in Tanzania. Within the western Kenya 1a subclade, 8 lineages were observed and 5 within the eastern Kenya 1b subclade. The amino acid homologies of the N gene between the study sequences and the vaccines for RABV were found to be approximately 97.6% for the PV vaccine strains, 98.5% for PM, and 97.8% for CVS. Similarly, the homologies with the G gene were at least 92.95% for PV, 92.19% for PM, and 93.3% for CVS. Our findings corroborate the geographic segregation of RABV between the eastern and western regions of Kenya. The data indicates that there is restricted viral movement, likely facilitated by the transportation of domestic dogs by humans. Good vaccine efficacy is predicted by the low amino acid variations in the antigenic sites of RABV vaccines and the study samples, suggesting that a lack of programmatic vaccination coverage is a major contributor to the endemicity of RABV in Kenya.
Genetic Diversity of Aphid Species Attacking Amaranth and Nightshades in Different Agro-Ecological Zones of Kenya and Tanzania
(University of Embu, 2016-09) Kipnyargis, Alex C.
Aphids are the major pests of vegetables leading to a significant yield loss in African indigenous vegetables including amaranth and nightshades. Information on the types of aphids that infest these vegetables and their genetic diversity in Kenya and Tanzania is scanty. This is an important diagnostic component in developing management strategies such as integrated pest management and early detection and control of invasive species. This study used a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene region called the barcode region to characterize the species of aphids that attack amaranth and nightshades in different agro-ecological regions of Kenya and Tanzania. Individual aphid samples were collected in 22 localities of amaranth and nightshade growing zones of the two countries, representing low, mid and high altitude agro-ecological zones. Total DNA was isolated and amplified using universal barcoding primers targeting the 5’ end of the COI barcode region. There was a strong homology (≥ 98% identity) in nucleotide sequences of the barcode region using the Basic Local Alignment Search tool for nucleotides (BLASTn) in the GenBank to four main species of aphids namely: Myzus persicae, Aphis fabae, Aphis craccivora and Macrosiphum euphorbiae. Further, three subspecies of the black bean aphid were identified as A. fabae fabae, A. fabae ciirciacanthoidis and A. fabae solanella. Intra-specific nucleotide diversity indicated that M. euphorbiae had no genetic diversity (0.0%); while A. fabae had the highest diversity (0.8%). The lowest inter-specific diversity was observed between A. fabae and A. craccivora (6.3%) while the highest was observed between A. craccivora and M. persicase (10.6%). The phylogenetic tree constructed using the maximum likelihood model showed each individual species clustering in robust clades irrespective of the host crop or the locality from which it was collected. This confirmed the BLASTn results. The principal coordinate analysis (PCoA) and the haplotype network analyses further confirmed these results by showing species clustering together in their space and haplotypes, respectively. Overall, COI successfully identified the species of aphid infesting amaranth and nightshades. This forms an important diagnostic tool for management strategies, early detection of newly evolving biotypes, deployment of resistant crop cultivars and containment of invasive species.
Genetic diversity of selected kenyan eucalyptus species and their suitability as power transmission poles
(DAISY CHEBET, 2024-08)
Eucalyptus is a genus in the Myrtaceae family that has many varieties of species. Among these species, Eucalyptus grandis, E. globulus, E. saligna and E. camaldulensis are majorly found in Kenya. E. grandis is the only species that is preferred for use as a source of power transmission poles. This species is known to mostly depend on high rainfall but due to global warming, there is insufficient rainfall making E. grandis to be unavailable hence the demand for this particular species is not met in electrification. There are other Eucalyptus species that occur naturally such as E. camaldulensis and E. globulus, and therefore it was important to carry out molecular phylogenetics and analyze the phenotypic traits of these other species to inform their use as power transmission poles in order to avoid the over exploitation of E. grandis. In this study, the phenotypic traits investigated included measuring tree height and diameter at breast height (DBH), while molecular data was obtained from sequences of MatK, RbcL and TrnL-F genes from the selected species. Evolutionary analyses such as nucleotide substitution rates, base composition disparity index, evolutionary divergence, nucleotide diversity indices and phylogeny construction were conducted in MEGA 11. Significant differences in DBH and height among Eucalyptus species were noted when the phenotypic data was analyzed using ANOVA (p≤0.05). The results obtained suggested that E.robusta, E.paniculata, E.maculata, E.dunnii, E. camaldulensis and E.citriodora might be used as power transmission poles but they are limited due to their shorter height (<30 meters). However, E. tereticornis and E. glaucina have the prefered DBH (18.3–28.3 cm) and height (>30 meters) and hence can be used as substitutes for E.grandis. Generally, the molecular phylogeny study suggested that most of the studied Eucalyptus species have a common ancestor because of the short genetic distances between them, low substitution rates and low nucleotide bias disparity index. The resulting phylogenetic trees will enhance knowledge on genetic relatedness of Kenyan Eucalyptus species as well as enhancing the efforts towards improvement and identification of known species with standard DBH and height for use as power transmission poles. Further studies involving more Eucalyptus species from various regions are needed to better understand the genetic diversity of the genus Eucalyptus and identify more species for use as alternative power transmission poles.

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