Potchefstroom, South Africa

North West University South Africa

Potchefstroom, South Africa

The North-West University is a newly merged institution from 1 January 2004 onwards with three campuses at Potchefstroom, Mahikeng and Vanderbijlpark, South Africa. The Potchefstroom Campus is the largest, and the head office of the University is situated at this location. With its merged status, the North-West University became one of the largest universities in South Africa and has 64 081 students .The universities that merged to form this institution are the Potchefstroom University for Christian Higher Education and the University of North-West . These two campuses form the main hubs of the university, with the Potchefstroom campus catering to Afrikaans speakers and the Mahikeng campus being broader in orientation. Wikipedia.

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North West University South Africa | Date: 2016-09-23

This invention relates to a method of producing a recombinant enzyme, more particularly, this invention relates to a method of producing water soluble enzymatically active recombinant glycine N-acyltransferase (GLYAT (E.G., including the steps of providing a suitable expression host; preparing a vector including a gene for expressing GLYAT in the expression host to form an expression plasmid; transforming the host with the expression plasmid to form an expression system; expressing the GLYAT gene in the expression system; and separating the expressed GLYAT from the expression system.

North West University South Africa | Date: 2017-09-27

This invention relates to a method of producing a recombinant enzyme, more particularly, this invention relates to a method of producing water soluble enzymatically active recombinant glycine N-acyltransferase (GLYAT (E.C., including the steps of providing a suitable expression host; preparing a vector including a gene for expressing GLYAT in the expression host to form an expression plasmid; transforming the host with the expression plasmid to form an expression system; expressing the GLYAT gene in the expression system; and separating the expressed GLYAT from the expression system.

Kabanda M.M.,North West University South Africa
Chemical Research in Toxicology | Year: 2012

Rooperol is a norlignan derivative with numerous biological activities including immunomodulatory, antitumor, anticonvulsant, antibacterial, and antioxidant activities. Its antioxidant activity has been studied by means of experimental techniques, which have shown that it has the ability to scavenge radical species, inhibit lipid peroxidation, and reduce transition metal ions. However, its ability to scavenge radical species and chelate transition metal ions has not been previously studied by means of quantum chemical methods. In this study, density functional theory (DFT) is utilized to investigate the conformational preferences of rooperol, the ability of rooperol to scavenge radical species, and the rooperol⋯Cu interaction mechanism, which might assist in understanding the antioxidant and prooxidant activities of rooperol. The study was performed in vacuo and in selected solvents. The results suggest that lowest-energy conformers of neutral rooperol are stabilized by two intramolecular hydrogen bonds, while the radical species of rooperol are stabilized by both intramolecular hydrogen bonds and spin delocalization of the unpaired electron. The results in different solvents show that the stability of the conformers of rooperol increases with the increase in the solvent polarity, while the stability of radical species decreases with increase in solvent polarity. The stability of the rooperol⋯Cu complexes depends on the site on which the Cu ion binds, while the binding strength depends on both the nature of the cation and the nature of the binding site. The inclusion of solvent effects using the polarizable continuum model shows that the rooperol⋯Cu interaction energies are highly overestimated in vacuo. Finally, the results suggest that the antioxidant activity shown by rooperol corresponds to its interaction with closed-shell transition metal ions, while its prooxidant activity is a result of its interaction with open-shell transition metal ions. © 2012 American Chemical Society.

Mason S.,North West University South Africa
Frontiers in Neuroscience | Year: 2017

Understanding brain energy metabolism-neuroenergetics-is becoming increasingly important as it can be identified repeatedly as the source of neurological perturbations. Within the scientific community we are seeing a shift in paradigms from the traditional neurocentric view to that of a more dynamic, integrated one where astrocytes are no longer considered as being just supportive, and activated microglia have a profound influence. Lactate is emerging as the "good guy," contrasting its classical "bad guy" position in the now superseded medical literature. This review begins with the evolution of the concept of "lactate shuttles"; goes on to the recent shift in ideas regarding normal neuroenergetics (homeostasis)-specifically, the astrocyte-neuron lactate shuttle; and progresses to covering the metabolic implications whereby homeostasis is lost-a state of allostasis, and the function of microglia. The role of lactate, as a substrate and shuttle, is reviewed in light of allostatic stress, and beyond-in an acute state of allostatic stress in terms of physical brain trauma, and reflected upon with respect to persistent stress as allostatic overload-neurodegenerative diseases. Finally, the recently proposed astrocyte-microglia lactate shuttle is discussed in terms of chronic neuroinflammatory infectious diseases, using tuberculous meningitis as an example. The novelty extended by this review is that the directionality of lactate, as shuttles in the brain, in neuropathophysiological states is emerging as crucial in neuroenergetics. © 2017 Mason.

Loots D.T.,North West University South Africa
Antimicrobial Agents and Chemotherapy | Year: 2014

The most common form of drug resistance found in tuberculosis (TB)-positive clinical samples is monoresistance to isoniazid. Various genomics and proteomics studies to date have investigated this phenomenon; however, the exact mechanisms relating to how this occurs, as well as the implications of this on the TB-causing organisms function and structure, are only partly understood. Considering this, we followed a metabolomics research approach to identify potential new metabolic pathways and metabolite markers, which when interpreted in context would give a holistic explanation for many of the phenotypic characteristics associated with a katG mutation and the resulting isoniazid resistance in Mycobacterium tuberculosis. In order to achieve these objectives, gas chromatography-time of flight mass spectrometry (GCxGC-TOFMS)-generated metabolite profiles from two iso-niazid- resistant strains were compared to a wild-type parent strain. Principal component analyses showed clear differentiation between the groups, and the metabolites best describing the separation between these groups were identified. It is clear from the data that due to a mutation in the katG gene encoding catalase, the isoniazid-resistant strains experience increased susceptibility to oxidative stress and have consequently adapted to this by upregulating the synthesis of a number of compounds involved in (i) increased uptake and use of alkanes and fatty acids as a source of carbon and energy and (ii) the synthesis of a number of compounds directly involved in reducing oxidative stress, including an ascorbic acid degradation pathway, which to date hasn't been proposed to exist in these organisms. Copyright © 2014 American Society for Microbiology. All Rights Reserved.

Potgieter M.S.,North West University South Africa
Space Science Reviews | Year: 2013

The global modulation of galactic cosmic rays in the inner heliosphere is determined by four major mechanisms: convection, diffusion, particle drifts (gradient, curvature and current sheet drifts), and adiabatic energy losses. When these processes combine to produce modulation, the complexity increases significantly especially when one wants to describe how they evolve spatially in all three dimensions throughout the heliosphere, and with time, as a function of solar activity over at least 22 years. In this context also the global structure and features of the solar wind, the heliospheric magnetic field, the wavy current sheet, and of the heliosphere and its interface with the interstellar medium, play important roles. Space missions have contributed significantly to our knowledge during the past decade. In the inner heliosphere, Ulysses and several other missions have contributed to establish the relative importance of these major mechanisms, leading to renewed interest in developing more sophisticated theories and numerical models to explain these observations, and to understand the underlying physics that determines galactic cosmic ray modulation at Earth. An overview is given of some of the observational and modeling highlights over the past decade. © 2011 Springer Science+Business Media B.V.

Potgieter M.S.,North West University South Africa
Living Reviews in Solar Physics | Year: 2013

This is an overview of the solar modulation of cosmic rays in the heliosphere. It is a broad topic with numerous intriguing aspects so that a research framework has to be chosen to concentrate on. The review focuses on the basic paradigms and departure points without presenting advanced theoretical or observational details for which there exists a large number of comprehensive reviews. Instead, emphasis is placed on numerical modeling which has played an increasingly significant role as computational resources have become more abundant. A main theme is the progress that has been made over the years. The emphasis is on the global features of CR modulation and on the causes of the observed 11-year and 22-year cycles and charge-sign dependent modulation. Illustrative examples of some of the theoretical and observational milestones are presented, without attempting to review all details or every contribution made in this field of research. Controversial aspects are discussed where appropriate, with accompanying challenges and future prospects. The year 2012 was the centennial celebration of the discovery of cosmic rays so that several general reviews were dedicated to historical aspects so that such developments are briefly presented only in a few cases.

Fibrinogen γ' is known to influence fibrin clot structure in purified experimental models, but little is known regarding its influence on clot structure in plasma. Furthermore, the environmental and biological factors that affect its concentration are poorly described. We analyzed fibrinogen γ', total fibrinogen concentration, and fibrin clot structure in 2010 apparently healthy black South Africans and related them to traditional cardiovascular disease (CVD) risk factors. Fibrinogen γ' generally increased with increasing fibrinogen concentration, but a decreased γ'/total fibrinogen ratio was found at the highest total fibrinogen concentrations. Clot maximum absorbance increased with total fibrinogen and fibrinogen γ', but decreased with γ'/total fibrinogen ratio. Clot lysis time showed a stronger relationship with fibrinogen γ' than with total fibrinogen, whereby increased fibrinogen γ' delayed clot lysis. CVD risk factors (excluding fibrinogen) explained 20% and 3%, respectively, of the variance in fibrinogen γ' and the γ'/total fibrinogen ratio, with C-reactive protein making the biggest contribution. More than 50% of the variance in fibrinogen γ' and γ'/total fibrinogen ratio is explained by factors other than total fibrinogen or other traditional CVD risk factors. Our data show that fibrinogen γ' modulates plasma clot structure and fibrinolysis and is also influenced by factors other than fibrinogen.

A plant supporting formulation which is also suitable for use as a delivery vehicle, or a component of a delivery vehicle, for the delivery of one or more phytologically beneficial substances to a plant, and for enhancing the translocation of such delivered substance(s) in or on the plant, the formulation comprising a micro-emulsion constituted by a dispersion of vesicles or microsponges of a fatty acid based component in an aqueous carrier, the fatty acid based component comprising at least one long chain fatty acid based substance selected from the group consisting of free fatty acids and derivatives of free fatty acids. The dispersion is preferably characterized in that at least 50% of the vesicles or microsponges are of a diametrical size of between 50 nm and 5 micrometer. The dispersion is further also characterized in that the micro-emulsion has a zeta potential of between 25 mV and 60 mV.

North West University South Africa | Date: 2016-11-23

A circuit and a method of using a circuit to drive an insulated gate semiconductor device (12) comprising as a first terminal a gate (20) and at least second and third terminals (22, 24). The circuit comprises a charge storage device (14) and switching means (16, 116) connected in a series circuit to the gate of the semiconductor device to transfer charge from the charge storage device to the gate of the semiconductor device so as to switch the semiconductor device between one of an on state and an off state and the other of the on state and the off state. Sufficient charge to switch the device on is transferred from the charge storage device to the gate during a charge transfer stage which is complete prior to a change in the current flow between the second and third terminals (22, 24) of the semiconductor device and during which a voltage on the gate exceeds and then remains above a threshold voltage between the gate and the third terminal of the device.

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