Protein kinase C-zeta as a downstream effector of phosphatidylinositol 3-kinase during insulin stimulation in rat adipocytes. Potential role in glucose transport

Insulin provoked rapid increases in enzyme activity of immunoprecipitable protein kinase C-zeta (PKC-zeta) in rat adipocytes. Concomitantly, insulin provoked increases in 32P labeling of PKC-zeta both in intact adipocytes and during in vitro assay of immunoprecipitated PKC-zeta; the latter probably reflected autophosphorylation, as it was inhibited by the PKC-zeta pseudosubstrate. Insulin-induced activation of immunoprecipitable PKC-zeta was inhibited by LY294002 and wortmannin; this suggested dependence upon phosphatidylinositol (PI) 3-kinase. Accordingly, activation of PI 3-kinase by a pYXXM-containing peptide in vitro resulted in a wortmannin-inhibitable increase in immunoprecipitable PKC-zeta enzyme activity. Also, PI-3,4-(PO4)2, PI-3,4,5-(PO4)3, and PI-4,5-(PO4)2 directly stimulated enzyme activity and autophosphoralytion in control PKC-zeta immunoprecipitates to levels observed in insulin-treated PKC-zeta immunoprecipitates. In studies of glucose transport, inhibition of immunoprecipitated PKC-zeta enzyme activity in vitro by both the PKC-zeta pseudosubstrate and RO 31-8220 correlated well with inhibition of insulin-stimulated glucose transport in intact adipocytes. Also, in adipocytes transiently expressing hemagglutinin antigen-tagged GLUT4, co-transfection of wild-type or constitutive PKC-zeta stimulated hemagglutinin antigen-GLUT4 translocation, whereas dominant-negative PKC-zeta partially inhibited it. Our findings suggest that insulin activates PKC-zeta through PI 3-kinase, and PKC-zeta may act as a downstream effector of PI 3-kinase and contribute to the activation of GLUT4 translocation.     

Stability of two-layered fluid flows in an inclined channel

A linear stability analysis of two-layer fluid flows in an inclined channel geometry has been carried out. The onset of flow transitions and the spatio-temporal characteristics of secondary flows produced by the flow instabilities have been examined. The effects of density and viscosity stratifications and surface tension on flow structures also have been investigated at various values of Froude numbers (channel inclinations). Multi-domain Chebyshev–Tau spectral methods along with MATLAB QZ eigenvalue solver are used to determine the whole spectrum of the eigenvalues and associated eigenfunctions. The neutral stability diagrams and stability boundaries are constructed for various values of flow parameters. The onset of flow transitions and flow structures predicted by linear stability analysis are compared against experimental results and they agree reasonably well. The results presented in the present paper imply that the shear mode of flow transitions is the one likely to be identified in experiments.     

Combined buoyancy and viscous effects in liquid–liquid flows in a vertical pipe

This paper presents experimental and numerical results of interfacial dynamics of liquid–liquid flows when an immiscible core liquid is introduced into a continuous liquid flow. The fully developed flow model predicts multiple solutions of the jet diameter over a range of dimensionless numbers: flow rate ratio, viscosity ratio, Bond and Capillary numbers. Experiments have been carried out using Polyethylene Glycol (PEG) and Canola oil to investigate the realizability of the three possible solutions predicted by the fully developed flow model. The measured values of inner fluid radii agree very well with the lower branch of the three branched solution while deviating from the top branch beyond a critical flow ratio value. This deviation is attributed to the fact that the flow develops a non-axisymmetric solution at this critical point. Computational fluid dynamics simulations have also been performed to examine the developing core annular flow and to compare the analytical solution results of liquid jet radius. The results predicted by numerical simulations agree very well with both the lower and upper branches of solution predicted by the analytical theory.     

Identification of phenolic profiles,fatty acid compositions,antioxidant activities,and enzyme inhibition effects of seven wheat cultivars grown in Turkey: A phytochemical approach for their nutritional value

In the present article, seven wheat cultivars (Ahmetaga, Bezostaya, Dagdas-94, Ekiz, Karahan-99, Konya-2002, and Tosunbey) grown in Turkey were compared for their phytochemical composition, antioxidant, and enzyme inhibitory activities. Antioxidant capacities and enzyme inhibitory effects were investigated with colorimetric methods. Total phenolic content ranged from 40.71 to 86.34 mg of gallic acid equivalent/100 g wheat grain. Tosunbey (92 mg Trolox equivalent/100 g wheat grain) and Ahmetaga (114.56 mg Trolox equivalent/100 g wheat grain) cultivars exhibited strong 2,2 azino-bis (3-ethylbenzothiazloine-6-sulfonic acid) and 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activities. As compared to other wheat cultivars, Tosunbey cultivar had remarkable both antioxidant and enzyme inhibitory effects with the highest level of phenolics. Ferulic acid, chlorogenic acid, and apigenin were the major phenolics in extracts tested. This study suggested that an increased intake of wheat derived products could represent an effective strategy for the management of oxidative stress related chronic and degenerative diseases such as Alzheimers and diabetes mellitus.     

Effect of differential processing methods on L-Dopa and protein quality in velvet bean, an underutilized pulse

Different accessions of velvet bean were subjected to traditional and technological processing methods like soaking, germination, microwave cooking, dry heating and γ-irradiation with a view to assess the extent to which the L-Dopa gets reduced. Furthermore, the impact of certain processing methods on the levels of total protein and essential amino acid profiles was also assessed. The percentage of L-Dopa in the raw seeds ranging from 5.63 (Mundanthurai white-coloured) to 4.44 g/100 g DM (Mundanthurai black-coloured). The processes of germination (120 h) and soaking in Ca(OH)₂ solution effected significant reduction in the content of L-Dopa (i.e., from 34.8% to 58.4%; and 5.6% to 54.5%, respectively). On the contrary, dry heat treatment and microwave cooking appeared to be less effective in reducing the contents of the same. While, γ-irradiation at 10 kGy seemed to be more effective in reducing the L-Dopa than at 5 kGy. Soaking in calcium hydroxide, microwave cooking and γ-irradiation had little impact on the profiles of essential amino acids except cystine (which was completely deactivated) in both the accessions of Thachenmalai. Nonetheless, in Thachenmalai (black-coloured) accession upon soaking in calcium hydroxide, the levels of valine, phenylalanine, tyrosine, isoleucine and histidine were found to be comparable with FAO/WHO (1991) requirement pattern. To sum up, of the various processing methods employed in the present study, germination and soaking in calcium hydroxide were effected greater reduction in L-Dopa content and caused minimum effect on the profiles of essential amino acids of seed proteins.     

Chemical Composition,Amino Acid Content and Protein Quality of the Little-Known Legume Bauhinia purpurea L

Some nutritional and antinutritional characteristics and biological value of Bauhinia purpurea L seeds were studied. The mature seeds contained (g kg^-1 as is) 271·7 crude protein, 58·7 crude fibre, 124·5 crude fat, 29·3 ash and 515·3 carbohydrates. Potassium, phosphorus and iron occurred in higher concentrations when compared with commonly consumed legumes. The globulins and albumins together constituted major storage proteins (82% total protein). The essential amino acid profile of total seed proteins compared well with the FAO/WHO reference pattern except for a deficiency of sulphur-containing amino acids and tryptophan. When compared with the globulins, the albumins appeared to be a rich source of cystine, methionine, threonine, lysine and tryptophan. Seed lipids contained high levels of the unsaturated fatty acids, oleic and linoleic, which accounted for 62·6% of total fatty acids recovered. Both dry heating and autoclaving significantly reduced the antinutritional compounds. The in vitro protein digestibilities of raw, dry-heated and autoclaved seeds were 59·5, 72·3 and 78·7%, respectively. True digestibility and net protein utilisation were significantly higher in processed seed samples compared with raw seeds. Regarding utilisable protein, autoclaved samples exhibited relatively higher values than raw seeds. © 1997 SCI.     

Synthesis of some novel 2-oxo-pyrano(2,3-b)- and 2-oxo-pyrido(2,3-b)quinoline derivatives as potential antimalarial,diuretic, clastogenic and antimicrobial agents

The 2-chloro-3-formyl quinoline derivatives ( 1a–e ) on treatment with acetic anhydride and sodium acetate, afforded the corresponding novel 2-oxo-pyrano(2,3-b) quinoline derivatives ( 2a–e ), and these were subjected to ammonia treatment to yield the corresponding naphthyridine derivatives ( 3a–e ). The prepared compounds ( 2a–e ) were tested for their antimalarial, diuretic, clastogenic and antimicrobial properties. Not all the compounds showed a diuretic effect and the significant increase in the frequency of micronuclei shows that they are non-clastogens, whereas the 7-chloro derivative ( 2e ) was a very effective antimalarial agent against the mosquito species. All the compounds were found to have optimum antimicrobial activity against Staphylococcus aureus, Escherichia coli and Salmonella typhi. Compounds 2d and 2e were found to be most active against the bacteria tested. © 1998 SCI     

Crosslinkable coupling agents: Synthesis and use for modification of interfaces in polymer blends

A novel coupling agent containing 2-oxazoline and 2-oxazinone as well as hydrosilane moieties has been prepared by hydrosilylation of the corresponding allyl ether containing precursor with a methylhydrosiloxane-dimethylsiloxane copolymer. This hydrosiloxane containing coupling agent, termed as SCA, was characterized by ¹H NMR and its crosslinkability was proven by DSC. SCA was used for the modification of the interfaces in heterogeneous polymer blends. In a model blend system based on mono-carboxylic acid terminated polystyrene (PS-COOH) and mono-amino terminated poly(methyl methacrylate) (PMMA-NH₂) the 2-oxazoline and 2-oxazinone units of SCA can selectively react with the carboxylic groups or amino groups, respectively. The remaining hydrosilane units partially crosslink under the used mixing conditions.The morphology of the three-component blends prepared by melt mixing was evaluated. SCA is immiscible with the polymers and forms its own phase. The expected location of the SCA at the interface between the polymers was proven only in an annealed, strongly phase separated blend. Overall the effect of the compatibilizer on the morphology is very small. Neither the domain size nor the composition for phase inversion are significantly affected in this blend system by the presence of SCA.     

The nutritional and antinutritional attributes of sword bean [Canavalia gladiata (Jacq.) DC.]: an under-utilized tribal pulse from south India

Six accessions [three with maroon‐coloured seed coat and three with white‐coloured seed coat) of sword bean (Canavalia gladiata (Jacq.) DC.], were collected from six different locations in south India. They were analysed for their proximate and mineral composition, amino acid profiles of total seed proteins, in vitro protein digestibility (IVPD) and certain antinutritional factors. The essential amino acid profile of total seed proteins compared favourably with FAO/WHO requirements, except that there were deficiencies of sulphur containing amino acids in all the six accessions and also the leucine, lysine and tryptophan contents were low in maroon‐coloured seed coat accessions. The IVPD of the accessions ranged from 63.39 to 76.92%. Antinutritional substances like total free phenolics, tannins, l ‐DOPA (3,4‐dihydroxyphenylalanine), trypsin inhibitor activity and phytohaemagglutinating activity were also investigated. The antinutritional factors that were detected were thought to have little nutritional significance if the beans are properly processed.