An assessment of the lipopolysaccharide toxicity of rough and smooth escherichia coli strains cultivated in the presence of zygosaccharomyces bailli

Thesis (M. Tech. Environmental health) -- Central University of technology, Free State, 2011In nature microorganisms do not exist alone, but in association with one another. These kinds of associations can also be found in food industries, where cells of the same or different species can attach to pipes (biofilm formation) and a variety of surfaces in food processing environments and in food product such as yoghurt which can contain both yeast and bacteria originating from the starter culture as well as fruit. To control food spoilage organisms and food-borne pathogens preventative measures such as good manufacturing processes, the use of sanitizers and preservatives as well as hazard analysis critical control points (HACCP) are crucial in food industries. Sanitation of the working surface, floors, pipes, containers and equipment is a stepwise application of a detergent, acid or alkali rinse, a disinfectant treatment followed by final rinsing. If rinsing of the sanitizer is not done properly it may end up in the product in sub-lethal doses. In this study the influence of Liquid Hypochlorite (LH) and Liquid Iodophore (LI) sanitizers on organism growth and toxicity was evaluated. The organisms investigated included Escherichia coli 0113, Escherichia coli 026 and Zygosaccharomyces bailii Y-1535 in yeast malt broth, which was supplemented with LH and LI at sub-lethal concentrations 0.05% LH, 0.2% LH and 0.075% LI. Subsequently, bacterial and yeast growth responses as pure cultures and in combination (E. coli + Z. bailii) were measured as colony forming units and optical density values. Incorporation of the sanitizers in the growth media resulted in different levels of growth inhibition. Z. bailii proved more robust and the growth rate was not influence significantly by the addition of sanitizers or communal growth with either E. coli strains. The growth rate of both E. coli strains decreased where grown in combination with Z. bailii as well as in the presence of sanitizers, with the most influence exerted by LH. Changes in endotoxicity following the growth of the test samples (stressed cells) and the control (unstressed) were measured by the limulus amoebocyte lysate (LAL) and porcine IL-6 ELISA methods. Where E. coli strains were cultured together with Z. bailii the toxicity of tire mixture showed a decrease over time when measured with the limulus amoebocyte assay method. Interestingly the communal growth of the E. coli strains and Z bailii produced different toxicity profiles when the IL-6 porcine method was used, hi both cases, where E. coli strains were cultured together with Z. bailii the toxicity of the mixture showed an increase over tune when measured by this assay. Other than a similar toxicity profile for E. coli 0113 grown in pure culture, the comparison between results obtained using the LAL or porcine IL-6 methods yielded no correlation in determined toxicity. It was established that LH and LI sanitizers as well as communal growth had an influence in the toxicity of LPS/EPS and the method used to determine such toxicity should be carefully considered

The Impact Of European Union - South Africa Trade Development And Cooperation Agreement On Botswana, Lesotho, Namibia And Swaziland

This paper examines the impact of the European Union-South Africa Trade Development and Cooperation Agreement (EU-SA TDCA) on trade between the RSA and Botswana, Lesotho, Namibia and Swaziland (BLNS). The results indicate that demand for imports are income elastic and price inelastic. This implies that imported goods are necessary and consumers and producers of the BLNS countries depend on them. The results also indicate that the agreement between the RSA and the EU brought about increased imports to the BLNS countries. Demand for exports is also income elastic and price inelastic. The volume of exports to the RSA, from the BLNS, seems to increase following the agreement. The empirical findings imply first, that imports could have led to a crowding out of domestic production, which would negatively impact on domestic industry. Second, the EU-SA TDCA has benefited the BLNS countries by boosting their exports.EU-SA TDCA; Customs Union; SACU; Trade; BNLS; RSA.

A comparison of the HI and CO velocity dispersions of nearby galaxies

Includes abstract.Includes bibliographical references.Velocity dispersions are used to determine the stability of galactic disks against gravitational collapse to form stars, in some star formation recipes, in studies of gas dynamics, and to determine how much turbulence there is in the interstellar medium. Atomic hydrogen (HI) dispersions have been used in the studies of star formation and large-scale turbulence, despite stars forming in molecular clouds and the inner regions of galaxies being dominated by molecular gas. Carbon monoxide (CO) has been used as a tracer for molecular gas. In this work HI and CO dispersions were determined for a sample of nearby galaxies and they were compared to determine what the relationship between HI and molecular gas dispersions is

Conceptualising antecedents of systems innovation on information security risks

Abstract : This research represents a comprehensive conceptualisation of antecedents of systems innovation and how they affect systems innovation in an organisational context. It further examines the relationship between information security risks and systems innovation. Antecedents of systems innovation are identified based on the existing theories such as Diffusion of Innovation (DoI) and Organisational Innovation. This research makes use of new systems and technologies which include Big Data/Cloud Computing, Blockchain, Internet of Things (IoT), Virtual/Augmented reality and Artificial Intelligence (AI) to examine organisations strides towards systems innovation. This research is underpinned by the increase in systems innovation and the growing concerns of information security risks faced by organisations. A quantitative method of analysis was used to analyse data using statistical methods with a view to identify relationships between variables. Data collected shows that systems and technology must have increased benefits in order to be adopted and the complexity of systems does not affect the adoption of such systems and technologies. Individual characteristics were found to have no effect in systems innovation whereas organisational and environmental elements highly influence innovation in the organisation. A relationship could not be established between systems innovation and information security risks. This research highlights the importance of ensuring that new systems and technologies adds value to the organisation and equally important is to ensure management of organisational and environmental elements that affect systems innovation. Information security risks should also not be a deterrence for systems innovation.M.Com. (Business Management

Evaluation of oil cakes from Amarula (Sclerocarya birrea), Macadamia (Integrifolia) and Baobab (Adansonia digitate L.) as protein supplements for ruminant diets

The current research was done to evaluate the nutritive values and the ruminal degradation of dry matter (DM) and crude protein (CP) from three non-conventional oil cakes, viz: amarula (Sclerocarya birrea) (AOC), macadamia (Integrifolia) (MOC) and baobab (Adansonia digitate L.) (BOC). The oil cakes were collected from biodiesel producers in Limpopo Province, transported to the ARC-Animal Production campus, where proximate and ruminal nutrient degradation analysis were conducted. Triplicates samples from each oil cake were analyzed for the nutritive values, mineral and amino acids contents. Three rumen cannulated mid-lactating (days in milk; DIM: 180±5) Holstein cows weighing 667±43 kg body weight were allocated to determine the in situ ruminal dry matter (DM) and crude protein (CP) degradation. The cows were offered a totally mixed ration (TMR) (60 concentrate: 40 forage ratio) that was compounded according to their daily nutrient requirements, and were milking was done twice per day at 12 hrs intervals. The three oil cake samples were ground using a 2-mm screen after which sub-samples (6.5 g) were put in 10 x 20 cm; 50 μm pore size polyester bags to achieve 15 mg/cm² (ratio of the sample size to surface area). The bags were then fistulated in each cow’s rumen in triplicate for a period of 2, 4, 8, 16, 24, or 48 hrs. After being incubated, the bags were removed from the rumen and washed with cold (4°C) water in 20-L buckets. Following immersing in cold water, the bags were machine washed until clean water was obtained. The bags were then dried at 60 °C in an oven for 48 hrs. The dried bags were individually weighed, and the content of each bag were removed and stored into glass vial until analysis. The remaining two duplicate sets of each sample were rinsed using cold water in order to determine solubility at 0 hrs. The AOC had higher (P<0.05) ether extract (EE) and CP content than both BOC and MOC. Macadamia oilcake (MOC) and BOC had higher (P<0.05) fractions of fibre (NDF, ADF and ADL) compared to the AOC. The AOC had greater (P<0.05) content of essential amino acids than in the BOC and MOC. Additionally, AOC had a high (P<0.05) phosphorus, but low calcium and potassium concentration. While AOC had high effective degradability of DM, it also had high water soluble as well as DM and CP rapidly degradable fractions. Effective degradation of CP was higher in AOC and BOC than in MOC. However, BOC had a high insoluble but degradable fraction of CP. Further work to determine the toxicology of these non-conventional oil cakes and animal feeding experiments is neededAgriculture and  Animal HealthMSc. Agricultur

The perfect drought? Constraints limiting Kalahari agro-pastoral communities from coping and adapting

Rural Kalahari agro-pastoral communities of Southern Africa have been exposed to drought shocks throughout history and have adapted their livelihoods accordingly. Yet, drought continues to disrupt or threaten to disrupt their production systems. With semi arid Botswana as a case study, this paper hence sought to unearth the factors limiting agro-pastoral communities from adequately coping and adapting to drought. Low rainfall, which is also highly variable, coupled with relatively low soil fertility status make subsistence livestock keeping and crop cultivation risky. This marginal agricultural potential of the land is further compounded by other constraints. Some of the major constraints included persistence of droughts, limited diversification options outside agriculture, inadequate and poor quality drinking water (high salinity) for livestock, crop damage by wild animals as well as the current land tenure system which curtails the traditional response of livestock mobility during drought. All these factors may act solely or in combination to render rural communities vulnerable during droughts. It is therefore recommended that effective interventions be tailored to local conditions to enhance resilience among Kalahari&rsquo;s rural population.Key words: Adaptation, Botswana, coping, drought, variability, vulnerability

Understanding the Causes of Bush Encroachment in Africa: The Key to Effective Management of Savanna Grasslands

The increase in biomass and abundance of woody plant species, often thorny or unpalatable, coupled with the suppression of herbaceous plant cover is a widely recognized form of rangeland degradation. Bush encroachment therefore has the potential to compromise rural livelihoods in Africa, as many depend on the natural resource base. The cause of bush encroachment phenomenon is not without debate, but fire, herbivory, nutrient availability and rainfall patterns have been shown to be the key determinants of savanna vegetation structure and composition. In this paper, these determinants are deliberated upon, with particular reference to arid and semi-arid environments of Africa. To improve our current understanding of causes of bush encroachment, an integrated approach, involving ecological and indigenous knowledge systems, is proposed. Only through our knowledge of causes of bush encroachment, both direct and indirect, can better livelihood adjustments be made, or control measures and restoration of savanna ecosystem functioning be realized

The stellar velocity dispersion in nearby spirals: radial profiles and correlations

The stellar velocity dispersion, σ, is a quantity of crucial importance for spiral galaxies, where it enters fundamental dynamical processes such as gravitational instability and disc heating. Here we analyse a sample of 34 nearby spirals from the Calar Alto Legacy Integral Field Area (CALIFA) spectroscopic survey, deproject the line-of-sight σ to σR, and present reliable radial profiles of σR\ua0as well as accurate measurements of (σR), the radial average of σR\ua0over one effective (half-light) radius. We show that there is a trend for σR to increase with decreasing R, that (σR) correlates with stellar mass (M∗), and tested correlations with other galaxy properties. The most significant and strongest correlation is the one with M: (σR) ∞ M∗0.5. This tight scaling relation is applicable to spiral galaxies of type Sa-Sd and stellar mass M∗ ≈ 109.5\ua0-1011.5\ua0M. Simple models that relate σR\ua0to the stellar surface density and disc scale length roughly reproduce that scaling, but overestimate (σR) significantly

Angular momentum and local gravitational instability in galaxy discs: does QQ correlate with jj or M M\,?

We introduce a new diagnostic for exploring the link between angular momentum and local gravitational instability in galaxy discs. Our diagnostic incorporates the latest developments in disc instability research, is fully consistent with approximations that are widely used for measuring the stellar specific angular momentum, $j_{\star}=J_{\star}/M_{\star}$, and is also very simple. We show that such a disc instability diagnostic hardly correlates with $j_{\star}$ or $M_{\star}$, and is remarkably constant across spiral galaxies of any given type (Sa$\!-\!$Sd), stellar mass ($M_{\star}=10^{9.5}\!-\!10^{11.5}\,\mathrm{M}_{\odot}$) and velocity dispersion anisotropy ($\sigma_{z\star}/\sigma_{R\star}=0\!-\!1$). The fact that $M_{\star}$ is tightly correlated with star formation rate ($\mathrm{SFR}$), molecular gas mass ($M_{\mathrm{mol}}$), metallicity ($12+\log\mathrm{O/H}$) and other fundamental galaxy properties thus implies that nearby star-forming spirals self-regulate to a quasi-universal disc stability level. This proves the existence of the self-regulation process postulated by several star formation models, but also raises important caveats.Comment: MNRAS Letters, in press. Minor revision to match the accepted version (added Fig. 1, Sect. 3.2, the final paragraph of Sect. 4, references and clarifications

Potential for domestication and commercialization of Hoodia and Opuntia species in Botswana

The species Hoodia (Apocynaceae) and Opuntia (prickly pear) (Cactaceae) are highly efficient in water use and belong to the Crassulacean Acid Metabolism (CAM) group of plants. These plant species are quite abundant in Botswana especially in the Kalahari Desert, prickly pear being the most dominant even though they have received very little commercial attention in the country. Elsewhere in the world, prickly pear has multiple uses such as their utilisation in the pharmaceutical industry, as a source of food and drink for animals in the rural communities, and are important in the weaving and clothingindustry. Other important uses of the species are manufacturing of paper, making of toothpicks, needles, pins and for numerous essential products. Recently the world has been introduced to Hoodiagordonii or curorri that works as a natural appetite suppressant. This paper reviews the potential uses of Opuntia and Hoodia spp, identifies the important species used by communities in Botswana andrecommends protocols and instruments for research, cultivation, and commercialization of these species in the country