An improved single-step lysis protocol to measure luciferase bioluminescence in Plasmodium falciparum

This report describes the optimization and evaluation of a simple single-step lysis protocol to measure luciferase bioluminescence from genetically modified Plasmodium falciparum. This protocol utilizes a modified commercial buffer to improve speed of assay and consistency in the bioluminescence signal measured by reducing the manipulation steps required to release the cytoplasmic fraction. The utility of this improved assay protocol is demonstrated in typical assays that explore absolute and temporal gene expression activity

Lipid peroxidation is essential for α-synuclein-induced cell death.

Parkinson's disease is the second most common neurodegenerative disease and its pathogenesis is closely associated with oxidative stress. Deposition of aggregated α-synuclein (α-Syn) occurs in familial and sporadic forms of Parkinson's disease. Here, we studied the effect of oligomeric α-Syn on one of the major markers of oxidative stress, lipid peroxidation, in primary co-cultures of neurons and astrocytes. We found that oligomeric but not monomeric α-Syn significantly increases the rate of production of reactive oxygen species, subsequently inducing lipid peroxidation in both neurons and astrocytes. Pre-incubation of cells with isotope-reinforced polyunsaturated fatty acids (D-PUFAs) completely prevented the effect of oligomeric α-Syn on lipid peroxidation. Inhibition of lipid peroxidation with D-PUFAs further protected cells from cell death induced by oligomeric α-Syn. Thus, lipid peroxidation induced by misfolding of α-Syn may play an important role in the cellular mechanism of neuronal cell loss in Parkinson's disease. We have found that aggregated α-synuclein-induced production of reactive oxygen species (ROS) that subsequently stimulates lipid peroxidation and cell death in neurons and astrocytes. Specific inhibition of lipid peroxidation by incubation with reinforced polyunsaturated fatty acids (D-PUFAs) completely prevented the effect of α-synuclein on lipid peroxidation and cell death

Relation Liftings on Preorders and Posets

The category Rel(Set) of sets and relations can be described as a category of spans and as the Kleisli category for the powerset monad. A set-functor can be lifted to a functor on Rel(Set) iff it preserves weak pullbacks. We show that these results extend to the enriched setting, if we replace sets by posets or preorders. Preservation of weak pullbacks becomes preservation of exact lax squares. As an application we present Moss's coalgebraic over posets

Comparison of the absolute and relative efficiencies of electroporation-based transfection protocols for Plasmodium falciparum.

BACKGROUND: Several electroporation protocols exist to transfect exogenous DNA into Plasmodium falciparum. To date, however, only a subjective analysis of their relative efficiencies has been reported. METHODS: A time-course of luciferase reporter expression is used to provide an objective quantitative analysis of the absolute efficiency of three electroporation techniques; direct electroporation of ring stage infected erythrocytes, preloading of erythrocytes and a novel "double-tap" protocol that combines both approaches. RESULTS: Preloading of erythrocytes shows a mean efficiency of 9.59 x 10(-6), some 5-180 fold more efficient than matched experiments utilizing the "double-tap" and direct electroporation of ring stage infected erythrocytes alone, respectively. CONCLUSION: Evidence presented here provides the first quantitative assessment of both the absolute and relative efficiencies of a key molecular tool used to study the biology and pathogenesis of this important human pathogen

Thermal degradation behaviour of flame retardant unsaturated polyester resins incorporating functionalised nanoclays

This paper discusses the effect of nanoclays on thermal degradation of unsaturated polyester resin with and without conventional flame retardants. Unsaturated polyester nanocomposites were prepared by in-situ polymerization with exfoliated structures. Simultaneous DTA-TGA analysis showed that nanoclays reduce thermal stability of the unsaturated polyester resin below 6000C and after that there was no change. Nanoclays also reduce the onset of degradation temperature of the resin. Above 600 0C, char formation is enhanced but not to the same extent as reported in literature for other polymer (e.g., nylon, polystyrene, etc.) – nanocomposite structures. The effect of conventional flame retardants - ammonium polyphosphate, melamine phosphate with and without dipentaeythritaol and alumina trihydrate on thermal degradation of resin was also studied. All these flame retardants enhance char formation of the resin above 4000C and presence of nanoclays promotes further increase. Analysis of the thermogravimetric data indicates that this enhancement in char formation is not as much as expected when compared with similar other polymer - nanocomposite structures

Evaluation of bioluminescence-based assays of anti-malarial drug activity

Transgenic Plasmodium falciparum expressing luciferase offers an attractive bioluminescence-based assay platform for the investigation of the pharmacological properties of anti-malarial drugs. Here a side-by-side comparison of bioluminescence and fluorescence-based assays, utilizing a luciferase reporter cassette that confers a strong temporal pattern of luciferase expression during the S-phase of intraerythrocytic development, is reported

Combinatorial Games with a Pass: A dynamical systems approach

By treating combinatorial games as dynamical systems, we are able to address a longstanding open question in combinatorial game theory, namely, how the introduction of a "pass" move into a game affects its behavior. We consider two well known combinatorial games, 3-pile Nim and 3-row Chomp. In the case of Nim, we observe that the introduction of the pass dramatically alters the game's underlying structure, rendering it considerably more complex, while for Chomp, the pass move is found to have relatively minimal impact. We show how these results can be understood by recasting these games as dynamical systems describable by dynamical recursion relations. From these recursion relations we are able to identify underlying structural connections between these "games with passes" and a recently introduced class of "generic (perturbed) games." This connection, together with a (non-rigorous) numerical stability analysis, allows one to understand and predict the effect of a pass on a game.Comment: 39 pages, 13 figures, published versio

Surface modification of fabrics for improved flash‐fire resistance using atmospheric pressure plasma in the presence of a functionalized clay and polysiloxane

Improving flash fire resistance of otherwise flame resistant fabrics is a recognised challenge within the civil emergency and defence communities. Simulation of the flash fire condition using cone calorimetry has demonstrated the effectiveness of atmospheric plasma treatments in which either a functionalised nanoclay, a polysiloxane (poly(hexamethyldisiloxane)) or both are deposited on to plasma-activated fibre surfaces. Textile substrates comprised flame retardant (Proban®) cotton and a poly (meta-aramid) (Nomex®). Results show that the generated surface layer has a measurable effect on fabric ignition and burning characteristics when exposed in a cone calorimeter at heat flux levels up to 70 kW/m2. Reductions in peak heat release (PHRR) values are observed for all substrates especially for argon/clay and argon/clay/polysiloxane, plasma-treated samples, with reductions of over 50% being observed for Proban® cotton and smaller reductions (≤ 20%) for Nomex® fabrics. Both scanning electron microscopic and cone calorimetric studies show that these properties are retained after a simulated washing process including the argon/clay plasma-treated Proban® and Nomex® fabrics in which no potentially binding polysiloxane was present. This suggests that plasma-activated fibre surfaces in the presence of a functionalised clay enables relatively strong binding forces to be generated. The results provide further evidence in addition to our earlier reported studies, that atmospheric plasma treatment of fabric surfaces in the presence of a nanoclay produces an inorganic coating that confers reduced flammability at the high heat fluxes used suggesting increased resistance to flash fire ignition

Corn shelling percentage studies

Digitized 2007 AES MoU.Includes bibliographical references (page 28)