Browsing by Author "Chebet, Daisy"

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    The Antimicrobial Properties of Garlic Against the Common Food Spoiling Bacteria Escherichia Coli
    (University of Embu, 2019) Chebet, Daisy
    Garlic is known to have numerous beneficial effects for human health. However, little information is known on its mechanism of controlling microorganisms that cause human epidemics. This study aims at evaluating the use of garlic as a natural preservative and its inhibitory effect against common food spoiling pathogen Escherichia coli. The freshly collected garlic were chopped into small pieces, dried for a week and blended. 1.5g, 2g, 2.5g and 3g were soaked in equal volume of 15ml of distilled water and ethanol as a solvent in a 250 ml sterile conical flask and shaken vigorously. The crude extract was filtered and kept at o 4 C. E. coli was obtained from fecal sample from pigs in the University farm through serial dilution and spread plate methods in sterile MacConkey agar. An antibacterial activity of the individual extract was tested on the MacConkey agar by disc diffusion method. The inoculums were spread evenly over the entire surface by swabbing in the plates. Inoculated plates were allowed to dry for 10 minutes before placing the discs. Sterile paper discs (diameter 10mm) will be impregnated with different concentration of the extracts :( 1.5g; 2g, 2.5g and 3g) were soaked in equal volume of 15ml of distilled water and ethanol as a solvent in a 250 ml sterile conical flask. This procedure was done three times. The plates were incubated at 37 0 C 24hours. The zone of inhibition was then measured. Minimal inhibitory concentration was carried out by agar dilution method where concentrations of garlic extract were prepared by using dimethyl sulfoxide in the ratio of 1:1 and was diluted with equal amount of phosphate buffer saline pH of 7.0. Data was analyzed using one-way Analysis of Variance in SPSS software. This study provided an alternative natural way of food preservation against E. coli amongst the communities within and out of Embu County. It is therefore suggest that the garlic extracts can be used as potential source of natural antimicrobial compound which if applied to bakery products before it is used for commercialization in the form of nutraceutical food it will prevent proliferation of spoiling microorganisms.
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    Molecular Phylogeny of Selected Kenyan Eucalyptus Species Inferred from MatK, rbcL and TrnL-F Genes and Their Suitability for Power Transmission Poles
    (MDPI, 2022-04) Chebet, Daisy; Musila, Fredrick M.; Kituyi, Sarah N.; Muthike, George M.; Kaigongi, Magrate M.
    Genus Eucalyptus belongs to the family Myrtaceae and consists of more than 900 species, various hybrids and varieties. The major species that are grown in Kenya are Eucalyptus grandis, E. globulus, E. saligna and E. camaldulensis. Most Eucalyptus species are highly dependent on rainfall and this is challenged by climatic changes owing to global warming making it difficult to effectively match the availability of mature trees and the market demand especially for use as power transmission poles. With the widespread availability of other naturally occurring Eucalyptus species such as E. camaldulensis and E. globulus, it becomes important to determine the genetic diversity and to analyze the phenotypic traits of these species for suitability as power transmission poles in order to counter the overdependence on E. grandis. Phenotypic traits investigated included measuring total tree height and diameter at breast height (DBH), while molecular data were obtained from sequencing MatK, rbcL and TrnL-F genes from selected species and evolutionary analyses such as nucleotide substitution rates, base composition disparity indices, evolutionary divergence, nucleotide diversity indices and phylogeny construction were conducted in MEGA 11. Significant differences in DBH and height among Eucalyptus species were observed when the phenotypic data were subjected to ANOVA. In this study, E. robusta, E. paniculata, E. maculata, E. dunnii, E. camaldulensis and E. citriodora are fit to be used as power transmission poles but they are limited by their short height. However, E. tereticornis and E. glaucina have the desired DBH and height and hence can be used as substitutes for E.grandis. Generally, the molecular phylogeny study has shown that the studied Eucalyptus species are closely related and form various monophyletic clades which can be attributed to the short genetic distances, low substitution rates, low nucleotide bias disparity indices and low diversity scores. Further phylogenetic and gene expression studies involving more Eucalyptus species are needed to better understand Eucalyptus phylogeny, and diversity and identify species with similar genetic make-up to that of E. grandis which has been used extensively for the provision of electricity transmission poles.