Biochemistry and Microbiology
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Browsing Biochemistry and Microbiology by Author "Djarova, T."
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- ItemAngiotensin converting enzyme (ACE), Actinin (ACTN3), Tumour necrosis factor (TNF) gene polymorphism associated with biomarkers and physical characteristics in young African cricket players of Zulu origin(2012) Ramakoaba, Abigail; Djarova, T.; Grace, J.; Watson, G.Current research in biochemistry and genetics focuses on finding a relationship between genes and biomarkers that are playing a fundamental role in physical performance. A possible link between these genes, molecular adaptation to exercise training and various markers of physical performance has been established in the past decade. A handful of genes have been studied by scientists, among them are the Angiotensin Converting Enzyme (ACE), ACTN3 (Actinin) and the Tumor Necrosis Factor (TNF). The ACE gene which encodes the angiotensin converting enzyme has been studied in detail and is known for influencing human physical performance and trainability. ACTN3 gene encodes the actinin-3 protein, that is known to form part of the sarcomeric Z-line, anchoring the actin filaments together and maintaining the mechanical integrity of the muscles. The TNF gene is among less studied genes, it encodes the Tumor Necrosis Factor protein which initiates the production of interleukins and that results in the production of the inflammatory biomarker C- reactive protein (CRP). Cricket is like any other sport in whereby there are energy requirements, physical characteristics that have been accepted as indicators of good performance in the game (body mass index, hand grip, quadriceps and hamstring strength) which are assessed for the purpose of the study. This study therefore sought to explore the ACE I/D, ACTN3 R/X and TNF G/A gene polymorphism, biomarkers (uric acid (UA) lactate (LA) and CRP) changes and the association with physical tests in a previously unexplored cohort of African Zulu cricketers. The participants were 31 Africans males aged 20-27 years (n=14 cricketers and n=17 controls). The genotyping (blood spots) was performed by PCR amplification followed by restriction digestion. After ANOVA the association was examined using Chi2 maximum likelihood test and Fisher’s exact test. ACE genotyping for the whole group displayed a complete absence of II genotype, 67.7% DD and 32.3% ID genotypes. The frequency of D allele was 83.8% and I allele 16.2%. In cricketers DD and ID genotypes were 50% each compared to controls-83% DD and 17% ID. The D allele is associated with power/sprint performance and the I allele with endurance. ACTN3 genotype frequencies for the cohort were 90.3% RR and 9.7% RX. The XX genotype was absent. The R allele is linked to sports that require power/sprint and the X allele is related to endurance. No differences in genotype frequencies between the two groups were noted. R allele at extremely high frequency (100%) was associated with CRP (<3.0 mg/L) in cricketers (p=0.0001) and controls (p=0.0140). TNF genotyping displayed 42% GG, 45% GA and 13% AA for the whole cohort, but no differences between both groups. CRP (<3.0 mg/L) was associated (p=0.0001) with low A allele frequency (18% in controls and 40% in cricketers). Interestingly, a null homozygosis of both the ACE II and the ACTN3 XX genotypes was found for the first time in the cohort of Zulu cricketers. This research demonstrates high ACE D allele frequency and a strong ACTN3 R allele association with low CRP, UA and LA levels. This study provides evidence about the genotype distribution of previously unexamined cohort of African athletes.
- ItemAnti-nutritional constituent of Colocasia Esculenta (Amadumbe) : a traditional crop food in Kwazulu-Natal(2008) McEwan, Ronalda; Opoku, A.R.; Djarova, T.; Oyedeji, O.A.Colocasia esculenta L. Schott belongs to the family Aracea and is grown for its edible corms as a staple food throughout subtropical and tropical regions of the world. Amadumbe (the Zulu name for Colocasia esculenta) is consumed by and holds an important place in the diet of local rural people in Kwazulu-Natal, South Africa. Three Amadumbe phenotypes were evaluated for their nutritional qualities. Like all known tubers, the locally grown Amadume contained high carbohydrate levels, adequate protein and low lipid content. Essential fatty acids (linoleic and linolenic) were identified as components of the Amadumbe lipids. Amadumbe was generally low in mineral content, apart from potassium and magnesium levels that were relatively high. Some anti-nutrients (protease inhibitors, lectin, phenolic compounds, alkaloids, oxalates, phytates, cyanogens and saponin) present in Amadumbe were also identified and quantified. The anti-nutrient levels were generally low and thus may not pose an immediate effect on the health of consumers. Reduction of the anti-nutrients through processing (cooking, frying, roasting) was observed to enhance the nutritional value of these tubers. However, their presence suggests that a steady consumption may lead to toxic levels. Two proteins (Al and B2) with a-amylase inhibitor activity, and a steroidal saponin (gamma-sitosterol) were extracted and partially characterised. The a-amylase inhibitors were extracted and partially purified through ammonium sulphate precipitation and chromatographic fractionation on diethylaminoethyl (DEAE)-Sephacel and Sephadex G-100. The molecular weights of the two inhibitors were estimated to be 17 000 and 19 000 dalton, respectively. The inhibitors were fairly heat-stable, with optimum activity at 40° C? pH 6.0. Both inhibitors showed activity against mammalian a-amylases, but were devoid of activity against fungal amylases. Inhibitor A also showed activity against plant amylases. The steroidal saponin extracted from Amadumbe was characterized through TLC, HPLC, GC-MS, IR and NMR spectroscopic analysis and identified to be gamma- sitosterol, an isomer of beta-sitosterol which is known to have a variety of high biological activity. Studies of the effect of beta-sitosterol on absorptive and digestive enzymes in Sprague-Dawley rats revealed that oral administration of beta-sitosterol had no apparent gross or microscopic lesions in the liver, kidney or small intestine. The administered p-sitosterol significantly decreased serum aspartate aminotransferase (ALT) and alanine aminotransferase (AST) levels. Na+/K -ATPase and intestinal disaccharidases activities were also significantly reduced in beta-sitosterol fed rats. These results do suggest that even though Amadumbe is a neglected crop in South Africa, it is a highly nutritional crop; the consumption of it could be beneficial to diabetic and hypertensive patients.
- ItemThe antimicrobial activity of five food spices when tested against various gram-positive –and gram-negative microorganisms(2008) Seepersad, Kashimee; Basson, A.K.; Djarova, T.; Shandu, J.S.The discovery of antibiotics by Alexander Fleming in the early nineteen hundreds not only created an enormous breakthrough in medical treatment but along with it introduced the emergence of new and now what is considered an ever increasing number of multi-drug resistant pathogens. Like antibiotics, herbs and spices have been used traditionally by many, for the treatment of various aliments ranging from stomach indigestion, lesions of the skin to beauty therapy. At present it is estimated that about 80% of the world population rely on botanical preparations as medicines to meet their health needs as opposed to treatment by conventional medicine with spices creating a shelf of its own in the global medical cabinet. In this study, the antimicrobial potential of five spices (commonly known as ginger, cinnamon, turmeric, nutmeg and chilli) was analysed against various Gram positive- and Gram negative microorganisms namely, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Salmonella spp, Shigella spp and Staphylococcus aureus. Analysis of the results of sensitivity tests (disc and agar well diffusion assays) indicated each of the microorganisms to be completely inhibited, intermediately inhibited or completely resistant towards a particular spice extract. The formation of zones of inhibition present where inhibition had occurred indicated that the spice tested was effective as an antimicrobial agent when screened. Zones of absolute inhibition (greater than fifteen millimetres in diameter) were obtained during positive agar well and disc diffusion assaying with neomycin used as the antimicrobial agent of choice. Inhibition zones observed to be in the upper limit range (pertaining to the study) of 20 mm – 27 mm in diameter. Comparative studies using the test spices indicated that chilli, turmeric, nutmeg, cinnamon and ginger each demonstrated zones of inhibition within this limit at one or more laboratory testing. Chilli was the most active antimicrobial agent when tested and in some instances demonstrated antimicrobial effectiveness greater than that exhibited by the positive control neomycin. Turmeric, nutmeg, cinnamon and ginger however each demonstrated inhibition within the same range as that of neomycin. The observations of such inhibition amongst the spices were comparatively significant and demonstrated the potential use of these spices as antimicrobial agents with an efficacy that can be compared to that of the already recognized and widely used antibiotic, neomycin. The minimum inhibitory concentration (MIC) was successfully determined for each of the spice extracts. The reactions observed during MIC determination were confirmatory of the antimicrobial activity present in the extracts of each spice. Analyses of the results conclude that the active compounds present in the selected spices were effective against certain microbial species. This observation demonstrated that spice can and may be used in the treatment of bacterial infections. This could in the future be an alternative treatment to antibiotics for one or all of the microbial species investigated and in so doing allow the healing powers of spices to be acknowledged.
- ItemLactogenic activity of Gunnera perpensa L. (Gunneraceae) from South Africa(2010) Simelane, Mthokozisi B.C; Opoku, A.R.; Djarova, T.Gunnera perpensa L. (Gunneraceae) is a medicinal plant used by Zulu traditional healers to induce labor, expel the placenta after birth, to relieve menstrual pains, and to stimulate milk production. Phytochemical screening of the rhizomes revealed the presence of alkaloids, flavonoids, steroids, saponins, tannins and glycosides. Methanol extracts of G. perpensa exhibited strong scavenging of 2,2-Diphenyl-1-picryl-hydrazyl (DPPH) and 3-ethylbenzothiazoline-6-sulfonate (ABTS), but showed poor radical scavenging of nitric oxide, superoxide and hydroxyl radicals. At a concentration of 5 mg/100 ml, the extract was able to inhibit lipid peroxidation of the whole rat brain homogenate (71%) and lipoxygenase (30%) activity. The plant extract also contained reduced form of nicotinamide adenine dinucleotide (NADH, 3.8 ρm/g), and total phenol (248.45 mg/g). The total antioxidant capacity was 36% relative to ascorbic acid (AA) and 64% relative to butylated hydroxyl toluene (BHT). The effect of an aqueous extract of the rhizome of the plant on milk production in rats was also investigated. Female lactating rats that received oral doses of aqueous extract of G perpensa produced more milk than controls (P<0·05). Pup weight gain was also significantly higher than that in the control group (P<0.05). In addition, the mammary glands of rats treated with the extract showed lobuloalveolar development. The extract of G perpensa was found to stimulate the contraction of the uterus; the highest amplitude was 5.06±08mm. G perpensa extract inhibited (23%) fish-brain acetylcholinesterase activity. The plant extract did not significantly influence prolactin, growth hormone, progesterone, cortisol, ALT, AST, and albumin levels. It is inferred that the plant extract exerts its activity on milk production and secretion by stimulating lobuloalveolar cell development and the contraction of myoepithelial cells in the alveoli. The cytotoxicity of the extract (LC50) to brine shrimp larvae was 137.62 mg/ml and to two human cell lines (HEK293 and HEPG2) it was 279.43μg/ml and 222.33μg/ml respectively. It is apparent that the antioxidant and lactogenic activity of G. perpensa contributes to its effectiveness in folk medicine.
- ItemThe usefulness of multiple antibiotic resistance (MAR) indexing technique in differentiating fecal coliform bacteria from different sources(2008) Mthembu, Mathews Simon; Djarova, T.; Biyela, P.T.; Basson, A.K.Pollution of water sources with human fecal matter and associated intestinal pathogens poses a great risk to public health. Fecal contamination of water is not the only problem to communities that consume untreated water. The extent of the microbial contamination of water sources also needs to be considered when designing treatment regimes for the production of potable water. The more polluted the source of drinking water is, the more extensive and expensive treatment regimes have to be used to produce microbial risk-free water. For decades fecal coliform counts have been used as indicators of fecal contamination and the potential presence of intestinal pathogens in surface waters. However, fecal coliforms fail to provide information about the source of fecal contamination. Knowing the source of fecal contamination is vital in managing this problem in surface waters. This study explored the use of two techniques, multiple antibiotic resistance (MAR) indexing and caffeine detection as means of differentiating E. coli isolates from various sources. A total of 322 E. coli were isolated from domestic and wild animals as well as human sewage by using conventional culture methods. Standard chemical and biochemical tests were used to identify these isolates. All isolates were assayed against a battery of 10 antibiotics using the micro-dilution method. The results obtained were used to generate antibiotic resistance profiles which in turn were used to statistically group the isolates into different subsets. Caffeine detection by Thin Layer Chromatography (TLC) was used to differentiate between human and non-human derived E. coli isolates. The correct classification rate was 78% when MAR indexing was used and 50% when using caffeine detection. Sixty percent of E. coli from humans were correctly classified and 95.5% of E. coli from animals were correctly classified as non-humans sources respectively. The results of this study underscore the validity of MAR indexing as a method of bacterial source tracking. MAR indexing has great discriminatory power without the complexities and the high costs often associated with established genotype-based methods. Caffeine detection indicated an average classification rate (50%). With further research, caffeine detection may give another option for source tracking when genotyping methods are limited by either costs or lack of expertise. The use of combined techniques may provide a much more reliable and cost-effective option for bacterial source tracking when each technique used provide similar results.