DSpace Repository :: Browsing by Author "Neondo, Johnstone O."

Browsing by Author "Neondo, Johnstone O."

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Detection and Profiling of Antibiotic Resistance among Culturable Bacterial Isolates in Vended Food and Soil Samples
(Hindawi, 2020-09) Muriuki, Susan W.; Neondo, Johnstone O.; Budambula, Nancy L. M.
The emergence and persistence of antibiotic resistance remain formidable health challenges. This study aimed at detecting and profiling antibiotic resistance of bacterial contaminants in vended food and the environment. Seventy antibiotic-resistant bacterial isolates were isolated from fried fish, African sausages, roasted meat, smokies, samosa, chips (potato fries), vegetable salads, and soil samples collected from Embu Town and Kangaru Market in Embu County, Kenya. The antibiotic susceptibility test, morphological and biochemical characterization, antibiosis assay, polymerase chain reaction-based detection of antibiotic resistance genes, and sequencing of the 16S rRNA gene were done. Analysis of variance on all measured data was done, and Tukey’s honest test was used to compare and separate mean diameters of zones inhibition. Resistance of bacterial isolates to antibiotics 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, Salmonella spp., exhibited highly significant antibiosis against S. aureus recording a mean inhibition diameter and standard error (SE) of 16.33 ± 0.88 mm, respectively, at . The 70 bacterial isolates belonged to Bacillus, Paraclostridium, Lysinibacillus, Virgibacillus, and Serratia genera. The study isolated Bacillus wiedmannii (KC75) which is a risk group 2 as well as Serratia marcescens (KMP95) and Bacillus anthracis (KS606) which are risk group 3 organisms. The presence of antibiotic resistance genes Tet A, BlaTEM, StrB, Dfr A, Amp, and FloR genes was confirmed by a polymerase chain reaction. Samples from Kangaru Market recorded a higher (88.57%) proportion of resistant isolates as compared to isolates from Embu Town (11.43%). The study confirmed the presence of antibiotic-resistant bacteria in vended fast food and the soil in Embu Town and Kangaru Market. This study calls for continuous monitoring of bacterial status and hygienic handling of vended food.
Detection and Profiling of AntibioticResistance among Culturable Bacterial Isolates in Vended Food and Soil Samples
(Hindawi, 2020-08) Muriuki, Susan W.; Neondo, Johnstone O.; Budambula, Nancy
+e emergence and persistence of antibiotic resistance remain formidable health challenges. +is study aimed at detecting and profiling antibiotic resistance of bacterial contaminants in vended food and the environment. Seventy antibiotic-resistant bacterial isolates were isolated from fried fish, African sausages, roasted meat, smokies, samosa, chips (potato fries), vegetable salads, and soil samples collected from Embu Town and Kangaru Market in Embu County, Kenya. +e antibiotic susceptibility test, morphological and biochemical characterization, antibiosis assay, polymerase chain reaction-based detection of antibiotic resistance genes, and sequencing of the 16S rRNA gene were done. Analysis of variance on all measured data was done, and Tukey’s honest test was used to compare and separate mean diameters of zones inhibition. Resistance of bacterial isolates to antibiotics 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, Salmonella spp., exhibited highly significant antibiosis against S. aureus recording a mean inhibition diameter and standard error (SE) of 16.33 ± 0.88 mm, respectively, at P � 0.001. +e 70 bacterial isolates belonged to Bacillus, Paraclostridium, Lysinibacillus, Virgibacillus, and Serratia genera. +e study isolated Bacillus wiedmannii (KC75) which is a risk group 2 as well as Serratia marcescens (KMP95) and Bacillus anthracis (KS606) which are risk group 3 organisms. +e presence of antibiotic resistance genes Tet A, BlaTEM, StrB, Dfr A, Amp, and FloR genes was confirmed by a polymerase chain reaction. Samples from Kangaru Market recorded a higher (88.57%) proportion of resistant isolates as compared to isolates from Embu Town (11.43%). +e study confirmed the presence of antibioticresistant bacteria in vended fast food and the soil in Embu Town and Kangaru Market. +is study calls for continuous monitoring of bacterial status and hygienic handling of vended food.
Genetic diversity and population structure of wild and cultivated Crotalaria species based on genotyping-by-sequencing
(Plos One, 2022-09) Muli, Joshua K.; Neondo, Johnstone O.; Kamau, Peter K.; Michuki, George N.; Budambula, Nancy L.
Crotalaria is a plant genus that is found all over the world, with over 700 species of herbs and shrubs. The species are potential alternative food and industrial crops due to their adaptability to different environments. Currently, information on the genetic diversity and population structure of these species is scanty. Genotyping-by-sequencing (GBS) is a costeffective high-throughput technique in diversity evaluation of plant species that have not been fully sequenced. In the current study, de novo GBS was used to characterize 80 Crotalaria accessions from five geographical regions in Kenya. A total of 9820 single nucleotide polymorphism (SNP) markers were obtained after thinning and filtering, which were then used for the analysis of genetic diversity and population structure in Crotalaria. The proportion of SNPs with a minor allele frequency (maf) > = 0.05 was 45.08%, while the GuanineCytosine (GC) content was 0.45, from an average sequence depth of 455,909 reads per base. The transition vs transversion ratio was 1.81 and Heterozygosity (He) ranged between 0.01–0.07 in all the sites and 0.04 to 0.52 in the segregating sites. The mean Tajima’s D value for the population was -0.094, suggesting an excess of rare alleles. The fixation index (Fst) between the different populations based on the Wright Fst (1943) ranged from 0.0119 to 0.066 for the Eastern-Western and Nairobi-Western populations. Model based techniques of population structure analysis including structure, k-means and cross-entropy depicted eight clusters in the study accessions. Non-model based techniques especially DAPC depicted poor population stratification. Correspondence Analysis (CA), Principal coordinate analyses (PCoA) and phylogenetic analysis identified a moderate level of population stratification. Results from this study will help conservationists and breeders understand the genetic diversity of Crotalaria. The study also provides valuable information for genetic improvement of domesticated species.
Genetic diversity and use of African indigenous vegetables especially slender leaf
(Taylor and Francis, 2020-10) Muli, Joshua K.; Neondo, Johnstone O.; Kamau, Peter K.; Budambula, Nancy
African indigenous (AIVs), and traditional, vegetables play a role in food security. This review examines distribution, use, diversity, and techniques used to study AIVs with special interest on Crotalaria species. Google scholar, PubMed, and the open web were searched for published articles between 1990 and 2020. The AIVs are distributed in almost all African countries but are mostly consumed in East and West Africa. The distribution and genetic diversity of some common AIVs has been documented. There is a need to create awareness on the use and conservation of AIVs because of their role in food security and livelihoods.
A hybridization technique for orphan legumes: development of an artificial interspecific pollination protocol for Crotalaria spp.
(Taylor and Francis, 2020-08) Wasonga, Mercy A.; Arunga, Ester E.; Neondo, Johnstone O.; Muli, Joshua K.; Kamau, Peter K.; Budambula, Nancy
rotalaria brevidens: and C. ochroleuca commonly grown as vegetables have been extensively studied. However, information on breeding techniques is scanty. This study aimed to develop an artificial interspecific pollination protocol for two genotypes of Crotalaria with contrasting leaf and pod morphological features. The two are landraces that were previously collected from two counties in Kenya. The experimental design was a completely randomized design (CRD) in a greenhouse with C. ochroleuca as the female parent and C. brevidens as the male parent. Six-day-old flower buds of the female parent were emasculated. Pollen from a freshly opened flower was rubbed over the stigma of the emasculated flower. The pollinated stigma was inserted back into the keel petal and covered by the wing and standard petal. Data on success rate, pod, and seed production were subjected to analysis of variance. The developed artificial pollination method showed 75% success rate in the interspecies cross of C. ochroleuca and C. brevidens. Time of crossing did not significantly influence the success rate, pod, and seed production. The study demonstrated artificial interspecific pollination of Crotalaria by keel petal incision rubbing method. This protocol lays the foundation for genetic studies and improvement of Crotalaria spp.
Hyphaene compressa, an important palm in the arid and semi-arid regions of Kenya
(2020-06) Omire, Agnes; Neondo, Johnstone O.; Budambula, Nancy; Gituru, Robert; Mweu, Cecilia
Background: Peasant agroecosystems in Kenya are considered to be a continuum of integrated traditional farming systems and natural ecosystem conservancy programs. Hyphaene compressa (doum palm) exists in arid and semi-arid lands (ASAL) of Kenya. While research in these areas is focusing on new plants to be brought to the areas, there is no focus on doum palm, which is already adapted to these areas. Scanty ethnobotanical knowledge exists in the form of unpublished material. The study aimed to determine domestication status, management practices, important use categories, plant part value, biotic and abiotic stresses of H. compressa. Methods: Four sampling sites in the ASAL of Kenya were selected. Tharaka Nithi, Kwale, Tana River and Turkana. Responses of 79 informants were analyzed to establish doum palm domestication profile, uses, biotic and abiotic stresses affecting its growth. Results: The domestication status varied across the sampled areas, with most regions showing no willingness to domesticate the plant. The study revealed that doum palm has fourteen uses with food (fruit) use, and prevention of soil erosion (roots) recording the highest and the least fidelity level scores, respectively, in the sampled areas. The most observed biotic stress was human interference and pest infestation, while the observed abiotic stress was drought and salinity. Conclusion:The most important doum palm use is food. Due to the high usage and poor domestication, doum palm could be losing its gene pool and hence genetic diversity studies are important for its conservation.
Phenomic characterization of Crotalaria germplasm for crop improvement
(Cabi, 2021-03) Muli, Joshua Kiilu; Neondo, Johnstone O.; Kamau, Peter K.; Odari, Eddy; Budambula, Nancy
Background: Diversifcation of global food systems through exploration of traditional varieties and wild edible plant species is a focal mitigation strategy for food security worldwide. The present study determined the phenomic diversity of locally available, afordable and climate-resilient cultivated and wild Crotalaria species for breeding purposes. Methods: Seed samples were collected from diferent administrative counties in Kenya spanning diferent climatic zones. Other seeds were provided by the Genetic Resources Research Institute of Kenya. A randomized complete block design with three replications was used for agro-morphological evaluation of the 83 accessions used in this study. Data on quantitative and qualitative traits was collected. Cluster analysis on R and R-studio was used to generate a dendrogram by the Euclidian genetic distance and dissimilarity indices while the non-metric multidimensional scaling (NMDS) method was used to determine the spatial interrelationship between the accessions. The Pearson’s correlation coefcients were used to determine the relationships between qualitative and quantitative traits while the principal component analysis was used to discriminate the accessions. Results: Three edible species (C. brevidens Benth., C. ochroleuca G.Don, C. trichotoma Bojer.) were found to be cultivated by Kenyan farmers and a signifcant variation (p<0.0001) for all parameters under study was recorded. Agglomerative hierarchical clustering grouped the accessions into 8 major clusters. The NMDS ordination formed 15 and 6 groups based on counties and regions respectively. Conclusions: This study forms the basis for exploring novel breeding strategies among cultivated species, between wild and cultivated Crotalaria species as well as determining molecular markers linked to phenomic traits.
Plant Hybridization as an Alternative Technique in Plant Breeding Improvement
(2019-05) Mwangangi, Immaculate M.; Muli, Joshua K.; Neondo, Johnstone O.
For ages, plant breeders have relied on the genetic variability that results from sexually crossing plants within the same species. However, the variability that exists within species populations is inadequate, hence the need to exploit desirable traits of interest in distantly related or even unrelated plants through hybridization techniques. Hybridization can be categorized into two; sexual and somatic. Sexual hybridization, also referred to as wide or distant hybridization involves combining two genomes from different parental taxa through pollination, either naturally or by induction. Somatic hybridization involves the fusion of somatic cells instead of gametes, which highly depends on the ability to obtain viable protoplasts and eventually differentiate them to whole plants in vitro. The impacts of hybrids can either be positive or negative. Among the positive attributes of hybrids that have been exploited is heterosis, which results either from dominance, over-dominance or epistasis. Negative ones include sterility, arrested growth of the pollen tube and embryo abortion. To overcome these problems, chromosome doubling, the use of hormones such as 2, 4-Dichlorophenoxyacetic acid (2, 4-D) and embryo rescue have been employed to overcome sterility, arrested growth of pollen tubes and embryo abortion respectively. After the development of hybrids, different hybrid identification techniques have been used to test them such as the use of molecular and morphological markers, cytogenetic analysis and fluorescent in situ hybridization. The use of hybridization techniques in plant improvement remains a vital tool to cross species barriers and utilization of important attributes in unrelated crop plants which could not have been achieved through conventional techniques of plant breeding.
Witchweed’s Suicidal Germination: Can Slenderleaf Help?
(MDPI, 2020-06) Mwakha, Fridah A.; Budambula, Nancy; Neondo, Johnstone O.; Gichimu, Bernard M.; Odari, Eddy O.; Kamau, Peter K.; Odero, Calvins; Kibet, Willy; Runo, Steven
The parasitic plant Striga hermonthica (Delile) Benth. is stimulated to germinate by biomolecules (strigolactones) produced in the roots of host and some non-host plants. Non-hosts induce Striga’s suicidal germination and are therefore used as trap crops. Among trap crops, the Slenderleaf legume in the genus Crotalaria (Crotalaria brevidens (L.) Benth.) and (Crotalaria orchroleuca (G.) Don.) has been popularized in African smallholder farms. However, the Striga germination e ciency of these locally grown Crotalaria varieties (landraces) is unknown. Also unclear is Crotolaria’s extent to inhibiting Striga growth, post germination. Extensive parasite penetration can expose the trap crop to secondary infections and possible phytotoxicity from Striga. We used in vitro germination assays to determine the Striga germination e ciency of 29 Crotalaria landraces. Furthermore, we determined Crotalaria’s ability to inhibit Striga attachment and growth using histological analysis. We found that: (i) Crotalaria stimulated germination of Striga seeds at frequencies ranging between 15.5% and 54.5% compared to 74.2% stimulation by the synthetic strigolactone (GR24) used a positive control; (ii) Crotalaria blocked Striga entry at multiple levels and did not allow growth beyond the pericycle, e ectively blocking vascular connection with the non-host. Hence, Crotalaria is suitable as a trap crop in integrated Striga management.

Browsing by Author "Neondo, Johnstone O."

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