Candaele J.,VIB |
Candaele J.,Ghent University |
Demuynck K.,VIB |
Demuynck K.,Ghent University |
And 8 more authors.
Plant Physiology | Year: 2014
DNA methylation is an important and widespread epigenetic modification in plant genomes, mediated by DNA methyltransferases (DMTs). DNA methylation is known to play a role in genome protection, regulation of gene expression, and splicing and was previously associated with major developmental reprogramming in plants, such as vernalization and transition to flowering. Here, we show that DNA methylation also controls the growth processes of cell division and cell expansion within a growing organ. The maize (Zea mays) leaf offers a great tool to study growth processes, as the cells progressively move through the spatial gradient encompassing the division zone, transition zone, elongation zone, and mature zone. Opposite to de novo DMTs, the maintenance DMTs were transcriptionally regulated throughout the growth zone of the maize leaf, concomitant with differential CCGG methylation levels in the four zones. Surprisingly, the majority of differentially methylated sequences mapped on or close to gene bodies and not to repeat-rich loci. Moreover, especially the 59 and 39 regions of genes, which show overall low methylation levels, underwent differential methylation in a developmental context. Genes involved in processes such as chromatin remodeling, cell cycle progression, and growth regulation, were differentially methylated. The presence of differential methylation located upstream of the gene anticorrelated with transcript expression, while gene body differential methylation was unrelated to the expression level. These data indicate that DNA methylation is correlated with the decision to exit mitotic cell division and to enter cell expansion, which adds a new epigenetic level to the regulation of growth processes. © 2014 American Society of Plant Biologists. All rights reserved.
Muyela B.,Egerton University |
Shitandi A.,Kisii University |
Ngure R.,Egerton University
International Food Research Journal | Year: 2012
Polycyclic aromatic hydrocarbons (PAHs) are a large group of organic compounds included in priority pollutant lists because of their mutagenic and carcinogenic properties. Several studies have shown that exposure to benzo[a]pyrene (BaP), amember of the PAHs increases the risk of cancer. This study investigated the effects of firewood smoking and oil frying onthe BaP levels in Nile perch (Lates niloticus) sold in Western Kenya. The methodology involved BaP extraction with cyclohexane and dimethylformamide-water, clean up on silica gel column and determination by high performance liquid chromatography (HPLC) using fluorescence detection. Variable levels of BaP were detected ranging from 7.46 to 18.79 μg/kg in smoked fish and 4.17 to 11.26 μg/kg in oil fried fish. These levels were further compared with the regulatory limits. All smoked fish samples were found to exceed the acceptable Maximum residual limit (MRL) of 5 μg/kg while 20% of the oil fried samples were within theacceptable limit. BaP was not detected in raw fish samples analysed. It was concluded that firewood smokingas practiced in the study areas resulted in higher levels of BaP contamination compared to oil frying. ©All Rights Reserved.
Aming'a N.N.,Kisii University
Interdisciplinary Journal of Information, Knowledge, and Management | Year: 2015
Knowledge management and knowledge assets have gained much prominence in recent years and are said to improve organizational performance. Knowledge capture and acquisition mechanisms enhance organizational memory and performance. However, knowledge capture and acquisition mechanisms in higher education institutions are not well known. The aim of this study was to investigate the knowledge capture and acquisition mechanisms at Kisii University. This was a case study in which data were collected through interviews and questionnaires. Purposive sampling was used to determine interview participants while questionnaire respondents were selected through stratified random sampling. Qualitative and quantitative data were analysed using SPSS® student version 14; it revealed that there were various knowledge capture and acquisition mechanisms at Kisii University. It was also established that the University encountered various challenges in knowledge capture and acquisition and lacked some essential knowledge capture and acquisition mechanisms. In this regard, this study proposed knowledge capture and acquisition guidelines that may be adopted by the University to enhance its organizational memory and performance.
Ngoci S.N.,Kisii University |
Ngoci S.N.,Egerton University |
Matasyoh J.C.,Egerton University |
Mwaniki C.G.,Egerton University |
Mwendia C.M.,Egerton University
Eastern Journal of Medicine | Year: 2012
Indigofera lupatana Baker F. (locally known as Mugiti) has been used by Mbeere community of Kenya to treat cough, diarrhea, pleurisy and gonorrhea. These infectious diseases are caused by pathogenic microorganisms such as, Klebsiella pneumoniae, Salmonella typhi, Escherichia coli, and Neisseria gonorrhea, among others. Infectious diseases are a cause of morbidity and mortality in humans and animals. Their effects are further aggravated by drug resistance, making it difficult to contain these infections. This calls for search of new drugs that will mitigate these problems. Indigenous plants are promising as a cheap alternative source of new therapeutic agents. Powdered sample of I. lupatana Baker F. roots were extracted using methanol solvent. The resultant extract was subjected to anti-microbial assay. The extract showed the highest activity against Bacillus subtilis (28.0 mm), Bacillus cereus (22.0 mm), Escherichia coli (21.7mm), Staphylococcus aureus (16.7 mm), Klebsiella pneumonia (15.3 mm) and Proteus mirabilis (12.3 mm), Pseudomonas aeruginosa (11.7 mm), Salmonella typhimurium (11.3 mm). The phytochemical studies of extract fractions showed presence of phenolics, flavonoids, tannins, saponins, terpenoids, cardiac glycosides, steroids and phlobatannins. These compounds are responsible for the bioactivity of the sample fractions. The activity was greater among the Gram positive bacteria than Gram negative bacteria. The MIC ranged from between 25 to 400mg/ml.
Wachira W.M.,Egerton University |
Shitandi A.,Kisii University |
Ngure R.,Egerton University
International Food Research Journal | Year: 2011
Broiler chicken is often grown actively with antibiotics to attain maximum weight within a short period of time. The uncontrolled and unlimited use of these antibiotics may however lead to the accumulation of undesirable residues in the animals treated and their products. In the Kenyan poultry industry there are no inexpensive and easy to perform antibiotic residues screening methods with the capability for a high sample throughput, which can be used to rapidly sift large numbers of samples for suspect or potential non-compliant results. The aim of this study was to determine the limits of detection (LODs) of penicillin G (PEN G) in chicken tissues using a low cost microbiological method. Microbiological detection was achieved by agar well diffusion using Bacillus cereus and Bacillus subtilis. PEN G was detected below the maximum residue limits (MRLs) of 50 ng/g in both liver and kidney with the LODs being 2 times below the MRLs on these plates. It was concluded that both B. cereus plate at pH 7 and B. subtilis plate at pH 7 could be effectively used for routine screening for PEN G residues.