Light-Induced Changes in Phosphorylation Status of Low Molecular Weight Wheat Nuclear Proteins

A large number of polypeptides were phosphorylated when in vitro protein phosphorylation was carried out in nuclei isolated from dark-grown seedlings. For studying the effect of light, dark-grown seedlings were exposed to light and the isolated nuclear proteins phosphorylated in vitro. Although 4 h of white light was sufficient to alter the phosphorylation status of at least two polypeptides of 19 and 17 kD but the effect of light was more pronounced after irradiation for 8 h or more, leading to virtual disappearance of a 19 kD and emergence of a 17 kD phosphopolypeptide. Studies using norflurazon, a bleaching herbicide, indicate that, in addition to 19 and 17 kD phosphopolypeptides, another 21 kD phosphopolypeptide may be involved in the de-etiolation process. However, the nature of the photoreceptor involved in these light-induced changes in nuclear protein phosphorylation remains to be established.     

Mathematical Modelling of Lipase Catalysed Resolution of O-Acetyl and O-Formyl Derivatives of Secondary Alcohols

Lipase catalysed transesterification of O-acetyl and O-formyl derivatives of several sterically hindered secondary alcohols with n-butanol is studied. The reaction is mathematically modelled and the rate constants in the model are evaluated by transient parameter estimation procedure. Several models are considered for predicting the enantiomeric excess (ee) of the product and compared with experimental observations. It is found that the maximum ee depends only on the rate constants of the two competing reactions and not on the order of reaction. A second order model is found to predict the observed behaviour well. When the data is fitted to an equilibrium type of model developed by Chen et al. (1987), it is found that the rate of forward reaction is several orders of magnitude larger than the rate of reverse reaction. The effect of acetyl and formyl groups on the reactivity and selectivity are also discussed.     

Degradation of unpretreated and thermally pretreated polypropylene by soil consortia

Unpretreated (PP-UT) and thermally pretreated (at 80 °C for 10 days) polypropylene (PP-TT) films of 0.05 mm thickness were subjected to in vitro biodegradation in minimal medium with mixed soil culture for 12 months. In this period 10.7 and 0.4% weight loss was observed with PP-TT and PP-UT, respectively. The tensile strength decreased by 51.8 and 28.3%, the crystallinity increased by 28 and 33% and isotacticity increased by 3 and 9%, respectively, over the same time period. The ester carbonyl index in PP-TT increased up to 9 months and later decreased indicating abiotic followed by biotic process. No such changes were observed with PP-UT. Methyl group index decreased in both the cases indicating oxidation at the primary carbon. Increase in surface energy indicated that the polymer became hydrophilic. Surface changes were observed by SEM and AFM. A single culture was isolated at the end of 12 months and it was identified as Bacillus flexus. The morphology of the organism was rods in a chain and it was present in the form of an endospore.     

Improving the tablet characteristics and dissolution profile of ibuprofen by using a novel coprocessed superdisintegrant: A technical note

Summary and Conclusion  The coprocessed superdisintegrant proved to be superior to the physical blend in terms of flow due to size enlargement. Furthermore, the coprocessed superdisintegrant displayed superiority in terms of crushing strength, disintegration time, and drug dissolution. The advantages of the proposed method are easy adaptability in industry and the possibility of bypassing the existing patents in the ereas of quick disintegration and dissolution. Published: February 16, 2007