Water relations of Pseudomonas solanacearum

The growth of 16 strains of Pseudomonas solanacearum at different water activities was investigated. These studies were undertaken in order to understand the adaptive mechanisms to osmotic stress of bacteria colonizing plants and to elucidate bacterial persistence when the efforts to eradicate disease fail. Due to inadequate growth of some strains on GYS medium, 3 strains, 66, 64 and 46, were selected for further investigation. These strains showed varied growth patterns on growth media at different water activities, with strain 66 showing the highest tolerance at very low water activity, that is, at 0.970, than the other two strains. The variation observed in the osmotolerance of the strains is an indication of the subtle differences among the strains of the same species.Keywords: Pseudomonas solanacearum, water activity, osmotolerance, osmotic stressAfrican Journal of Biotechnology Vol. 9(35), pp. 5767-5774, 30 August, 201

Determination of ferulic acid and related compounds by thin layer chromatography

The analysis of certain phenolic compounds from plants, and their chemical transformation with microorganisms or isolated enzymes, has application in the food and pharmaceutical industry. The rapid quantitative estimation of ferulic acid by thin layer chromatography is described by measurementof the area of the obtained spots. Furthermore, the qualitative analysis of a number of related phenolics, some of which are transformation products of ferulic acid, is achieved on thin layer chromatographic plates by the use of different spray reagent

Volatile chemicals in glands of the carpenter ant, Camponotus arminius

Camponotus arminius is a large black carpenter ant that occurs in tropical and sub-tropical Africa and has extensive foraging trails both in trees and on the ground. Analysis of excised mandibular glands has confirmed The presence of pentane-2,4-dione, n-hexanal, 4-methyl-3-heptanone, and mellein. Pentane-2,4-dione has not been reported from insects. The postpharyngeal gland contains n-heneicosane, n-tricosene, n-tricosane, n-pentacosene, n-pentacosane, and a significant amount of 11-methyl- n-tricosaneand 11-methyl- n-pentacosane. Dufours glands contain mainly n-undecane, n-tridecane, and two terpenoid compounds that are unknown in the genus Camponotus. These latter two compounds are geranyllinalool and probably geranylfarnesol

Bioconversion of ferulic acid and 4-vinylguaiacol by a white-rot fungus isolated from decaying wood

A white rot fungus isolated from decaying wood was investigated for its ability to convert ferulic acid to various valuable products. The fungus is able to convert ferulic acid to 4-vinylguaiacol, which is then metabolized further to acetovanillone. Both products have potential use in the chemical manufacturing and pharmaceutical industries and these results contribute to our knowledge of the biotransformation of ferulic acid

The relationship between economic growth and electricity consumption in South Africa

In recent years, the relationship between electricity consumption and economic growth has been examined extensively in numerous countries. While there is high consensus in the scientific sphere on the interdependence between electricity consumption and economic growth, recent literature suggests that there are still competing views on the causal relationship between the two variables. Energy has long been viewed as a vital driving force for economies. However, the crucial role that the energy sector has played during the industrial revolution allowed some authors to consider energy in the same way as the capital and labor factors in the production function. The energy factor is considered essential today in the process of development. Almost everyone agrees on the importance of its contribution to the process of growth and development by considering growth / energy model as an indicator of wealth and a vector to reduce social inequalities. Meanwhile, according to the different scenarios observed, energy consumption may or may not have impacts on economic growth or wealth creation. The problem of access to energy (electricity) in certain regions in Africa (and particularly in South Africa) remains one of the major challenges that require urgent attention over the coming decades. In addition, the lack of consensus among researchers has triggered a shift towards focusing on study methods and techniques used for investigations on the energy-growth nexus. Using R programming for data analysis, this study investigates the asymmetric relationship between energy consumption and economic growth in South Africa by incorporating the following intermediary variables: trade openness, capital and labour. Results suggest that a conservation hypothesis is the most prevailing theory on the causal link between GDP and Energy Consumption in South Africa. This opinion is acknowledged as the growth-led electricity consumption opinion. From an economic perspective, evidence from the research suggests that, without necessarily expanding energy accessibility, trade liberalisation and capital could generate clear gains to South Africa and efforts to promote and accelerate these initiatives should be encouraged. Given the often-competing resource limitation challenges faced by the South African government, as a result of prioritisation, trade liberalisation should be favoured and be given roughly in the range of 1.5 times more attention than capital. Therefore, South Africa may not necessarily need electricity for its economic growth. Although energy consumption has a major influence on economic growth, the latter could also possibly be achieved by increasing trade and/or capital, without any change in energy consumption. Energy conservation policies could be executed with little or no hostile effects on economic growth. As a policy intervention, the research study recommends sustained efforts to strengthen regional integration with the view to achieving trade liberalisation, increasing capital formation and creating greater synergy for economic growth

The impact of mobile technologies on the business models of small and medium enterprises in Pietermaritzburg

The use of mobile technologies has permeated the business arena rapidly over the last decade. Research has been conducted to understand the nature of these mobile technologies and their adoption into business. With the ever growing importance of Small and Medium Enterprises (SMEs) in countries such as South Africa, there is need to better understand the impact of mobile technologies on SMEs. The objective of this study is to assess the impact of mobile technologies on the business models of SMEs. A theoretical definition of a business model is used to understand the impact of mobile technologies on the customer value proposition, the profit formula, key resources and the value chain of SMEs. The study takes into account some of the challenges that SMEs face, namely limited resources, low levels of productivity and small management teams. SMEs registered with the Pietermaritzburg Chamber of Business (PCB) are used as a sample to assess the impact of mobile technologies. The results show that mobile technologies have a significant impact on the profit formula and certain aspects of key resources. Specifically, mobile technologies are used to firstly cut costs and then to enhance the utilisation of assets, improve knowledge management while ensuring adequate governance structures. The outcome of this study can be used by SMEs to plan for the adoption of mobile technologies and measure their impact on the business. Mobile technology companies can consider the development of mobile technologies tailored for the SME environment.Dissertation (MBA)--University of Pretoria, 2012.Gordon Institute of Business Science (GIBS)unrestricte

Compositions and comparisons of antimicrobial potencies of some essential oils and antibiotics against selected bacteria

The antimicrobial activities of 10 essential oils extracted from various plant species were investigated and compared with the activities of 10 commercial antibiotics against 10 strains of bacteria using agardiffusion method. Although, all the essential oils were active at concentration ranging from 0.5 to 1.5 mg/ml, their activities were more lower than the commercial antibiotics. However, being natural productsthe oils have been reported to be much safer than the antibiotics. Another advantage of the essential oils used in this study was their broad spectrum activities against gram positive and gram negative bacteria. The oils were analyzed by GC and GC-MS techniques in order to determine their activecompounds

The proposed mechanism of bactericidal action of eugenol, &#8733-terpineol and g-terpinene against Listeria monocytogenes, Streptococcus pyogenes, Proteus vulgaris and Escherichia coli

The mechanism of antimicrobial activity of essential oils components; - terpineol, g-terpinene and eugenol was studied to evaluate their effect on the bacterial membrane against four strains of bacteria:Listeria monocytogenes, Streptococcus pyogenes, Proteus vulgaris and Escherichia coli. The study was done to observe changes in membrane composition by assaying for the leakage of protein and lipid using Bradford and van Handel’s method respectively. The oils components were capable of inducing cell lysis by the leakage of protein and lipid contents. Eugenol at 2 × MIC was highly effective toward protein content leakage after 120 min of exposure. Alpha terpineol and g-terpinene showed similar effect at 2 × MIC under the same condition. Gamma terpinene displayed the highest activity toward lipid content leakage at 2 x MIC while -terpineol and eugenol showed similar effect after 120 min of exposure. The result revealed that both cell wall and membrane of the treated gram negative and gram positive bacteria were significantly damaged

Kinetic Properties of α-Galactosidase and the Localization of Total Proteins in Erwinia chrysanthemi

Erwinia chrysanthemi is an enterobacterium that causes soft-rot in plants in general, resulting in enormous economic losses annually. For the pathogen to survive in the host plant, it has to use the readily assimilable compounds from the host fluids and degrade the host tissue. To accomplish this, E. chrysanthemi produces several extracellular and intracellular enzymes. Among the intracellular enzymes there is a special digestive class, the galactosidases, which can be either periplasmic or cytoplasmic. α-Galactosidase is known to degrade melibiose and raffinose into glucose and galactose, and into galactose and sucrose respectively. The aim of the present study was to investigate the kinetic properties of α-galactosidase in E. chrysanthemi, and the localization of total proteins, after culturing it in the presence of raffinose and melibiose. The α-galactosidase that degrades melibiose seems to be the same enzyme that is also responsible for the breakdown of raffinose in E. chrysanthemi. It is localized mainly in the cytoplasm with a fraction of between 2.4 and 5.4 % localized in the periplasm. The majority of E. chrysanthemi proteins have cytoplasmic localization

A marine bacterium, Oceanobacillus sp. Pinky, isolated from Algoa Bay sediment produces a thermostable glycoprotein flocculant

In this study, we report on the bioflocculant production potential of an Oceanobacillus sp. isolated from the marine sediments of Algoa Bay. The bacteria produced an extracellular bioflocculant optimally in the presence of sodium carbonate as source of carbon with flocculating activity of about 95.5%. Other optimal culture conditions included: tryptone as nitrogen source (flocculating activity, 84.5%); presence of Ca2+; inoculum size of 2% (v/v) and alkaline pH (10). Composition analyses revealed the purified bioflocculant to be thermostable and composed of polysaccharide and protein. Optimum dose of the purified bioflocculant for the clarification of 4 g/L kaolin clay suspension at neutral pH was 0.2 mg/ml. Scanning electron microscopic (SEM) observations were indicative of a porous bioflocculant structure while Fourier transform infrared (FTIR) spectrum revealed the presence of carboxyl, hydroxyl and amine groups. We proposed that the bacteria hold promise as a potential source of new bioflocculant compound(s).Keywords: Oceanobacillus sp., bioflocculant, glycoprotein, marine sediment, Algoa BayAfrican Journal of Biotechnology Vol. 12(26), pp. 4135-414