Comparative study of different methods for the extraction of DNA from fish species commercially available in South Africa

This study describes the comparison of five DNA extraction methods (urea-SDS-proteinase K; phenol-chloroform; salt extraction; SureFood^® PREP Allergen kit and Wizard^® Genomic DNA Purification kit) in terms of their ability to extract high yields of pure, readily amplifiable DNA from the muscle tissue of 29 fish species available in South Africa. Although variations in the yield and purity of extracted DNA were observed between methods, all five methods produced DNA suitable for PCR amplification. Overall, the SureFood^® PREP method was of the simplest and least hazardous to perform, extracting significantly (P < 0.05) higher DNA yields than all other methods evaluated.     

Enhanced PAA bleaching of cotton by incorporating a cationic bleach activator

Peracetic acid is a well-known alternative to hydrogen peroxide as a bleaching agent for cotton. In this study, a novel cationic bleach activator, N -[4-(triethylammoniomethyl)benzoyl]butyrolactam chloride, was used in combination with peracetic acid to investigate the enhancement of cotton bleaching efficiency. The effects of temperature, pH and concentrations of activator and peracetic acid on the bleaching performance were studied using a statistical design of experiment. Adding activator to a peracetic acid bleaching bath improved the resultant whiteness of the substrate and at optimal conditions produced less fibre damage than when peracetic acid was used alone. In addition, the bleaching performance of both peracetic acid and hydrogen peroxide in the presence of activator was compared. In the absence of activator, the peracetic acid performance was considerably superior to a conventional hydrogen peroxide bleach system in which no bleach activator is present. However, addition of activator to the hydrogen peroxide bath increased the whiteness to a level comparable to peracetic acid.     

Quality changes during ripening of plums (Prunus domestica L.)

Quality changes during fruit ripening after the appearance of fruit colour of four Prunus domestica L. plum cultivars, ‘Jojo’, ‘Valor’, ‘Čačanska rodna’ and ‘Čačanska najbolja’, were investigated during 25 or 33 day periods. Fruit samples were analyzed for fruit weight, firmness, soluble solids content, fruit colour, content of sugars (glucose, fructose, sorbitol and sucrose), organic acids (malic, fumaric and shikimic acids), phenolics (neochlorogenic acid, p-coumaroylquinic acid, chlorogenic acid and rutin) and anthocyanins (cyanidin-3-rutinoside and peonidin-3-rutinoside). Ripening resulted in statistically increased fruit weight and soluble solids, decreased fruit firmness, darker colour of fruits, increased concentration of total sugars, decreased concentration of total acids, and increased concentration of anthocyanins. There was no influence of ripening on the content of phenols. The results show significant influences of cultivar on fruit weight, soluble solids content, firmness, fruit colour, concentration of total acids, SUAC index, concentration of total phenols and anthocyanins in European plums.     

Dissociation of chemotaxis from agonist-induced receptor internalization in a lymphocyte cell line transfected with CCR2B. Evidence that directed migration does not require rapid modulation of signaling at the receptor level

To investigate the role of the carboxyl-terminal region (52 amino acids) of the monocyte chemoattractant protein 1 receptor (CCR2B) in chemotaxis, we created a series of mutants and expressed them in a murine pre-B lymphocyte cell line. Truncation of the cytoplasmic carboxyl tail to 20 amino acids had little or no effect on chemotaxis or signal transduction, but further truncation resulted in marked functional defects. Upon incubation with monocyte chemoattractant protein 1, CCR2B underwent rapid and extensive internalization, and this was impaired progressively as the carboxyl tail was truncated from 52 to 8 amino acids. Mutation of all of the serine and threonine residues in the carboxyl tail to alanine also resulted in markedly impaired receptor internalization but did not affect signaling or chemotaxis. We conclude that the membrane-proximal portion of the cytoplasmic carboxyl tail of CCR2B is critically involved in chemotaxis and signal transduction, but neither phosphorylation of carboxyl serines or threonines nor internalization of the receptor is required for robust chemotaxis.     

Vision and attention. II: Is visual attention a mechanism through which a deficient magnocellular pathway might cause reading disability?

Recent research in reading disability has discovered that at least some reading-disabled subjects have deficits in their magnocellular (M) visual pathways. However, the mechanism by which M pathway deficits affect reading has not been addressed. Abnormal attention has long been known to be associated with reading-disabled individuals, and new research in visual attention has determined that transient visual attention is dominated by M-stream inputs. The purpose of this study was to determine whether visual attention might be the mechanism through which a faulty M pathway could produce visual deficits in reading-disabled subjects. Spatiotemporal attentional response functions were measured using the Line Motion Illusion and compared in normal and disabled readers. Specific abnormalities in the visual attention mechanisms of disabled readers were found which might suggest mechanisms by which reading could be affected by a deficient M stream.     

Minimum structural requirements for peptide presentation by major histocompatibility complex class II molecules: implications in induction of autoimmunity

The precise mechanisms of failure of immunological tolerance to self proteins are not known. Major histocompatibility complex (MHC) susceptibility alleles, the target peptides, and T cells with anti-self reactivity must be present to cause autoimmune diseases. Experimental autoimmune encephalomyelitis (EAE) is a murine model of a human autoimmune disease, multiple sclerosis. In EAE, residues 1-11 of myelin basic protein (MBP) are the dominant disease-inducing determinants in PL/J and (PL/J x SJL/J)F1 mice. Here we report that a six-residue peptide (five of them native) of MBP can induce EAE. Using peptide analogues of the MBP-(1-11) peptide, we demonstrate that only four native MBP residues are required to stimulate MBP-specific T cells. Therefore, this study demonstrates lower minimum structural requirements for effective antigen presentation by MHC class II molecules. Many viral and bacterial proteins share short runs of amino acid similarity with host self proteins, a phenomenon known as molecular mimicry. Since a six-residue peptide can sensitize MBP-specific T cells to cause EAE, these results define a minimum sequence identity for molecular mimicry in autoimmunity.     

Polyacryl–nanoclay composite for anticorrosion application

Polyacryl–nanoclay composites are new class of materials obtained by dispersing montmorillonite clay nanoplatelets (nanoclay) into the polymer matrix. In present work we investigate and confirmed that montmorillonite nanoclay significantly enhances barrier properties of acrylic composite. Two stage of dispersion process was used to prepare polyacry–nanoclay composites. Different percentages of montmorillonite clay nanolayers were added to polyacryl dispersion and applied on steel panel with 0% (w/w), 1% (w/w), 2% (w/w) and 4% (w/w) of nanoclay as composites. Performance of nanoclay intercalation in polyacryl composite was measured by X-ray diffraction (XRD) and the structure characteristics of samples were analyzed with transmission electron microscopy (TEM). The effectiveness of prepared nanocomposites was identified by the hardness measurements and mechanical properties. Further anticorrosion characteristics, especially barrier properties were indirectly detected by electrochemical impedance spectroscopy (EIS). This method was also used for the determination of montmorilonite nanoclay optimal concentration in acrylic composite where optimal barrier properties were achieved.     

The measuring and control system for improved model based diastat filling quality

The article describes the development and testing of a measurement and control system in industrial environment. This system enables fast and accurate membrane expansion measurements. The membrane is part of the sensor system called diastat, which is filled with a special oil. The diastat is part of mechanical capillary thermostat. To demonstrate the right selection of the measurement equipment and data processing methods, several tests and analysis were performed: the dynamic response of the diastat membrane during filling, measuring accuracy, nonlinearity and temperature stability of the measurement system with integrated distance sensor and the most important verification measurements with reference control procedures in manufacturing process. It was demonstrated that a number of novel approaches need to be introduced enabling installation of the measurement and control system in the production of the thermostat diastats.