Flexural and Dynamic Mechanical Properties of Alkali-Treated Coir/Pineapple Leaf Fibres Reinforced Polylactic Acid Hybrid Biocomposites

Polylactic acid(PLA)possesses good mechanical and biodegradability properties which make it a suitable material for polymer composites whereas brittleness and high costs limit its utilization in various applications.The reinforcement of natural fibres with biopolymers has been formed to be an efficient technique to develop composites having the ability to be fully biodegradable.This study concerns with the incorporation of various percentages of untreated and alkali-treated Coir Fibres(CF)and pineapple leaf fibres(PALF)in PLA biocomposites and characterizations of flexural,morphological and dynamic mechanical properties.Flexural properties showed that the treated C1P1 hybrid composites(C1P1A)displayed highest flexural strength(35.81 MPa)and modulus(5.28 GPa)among all hybrid biocomposites.Scanning Electron Micros-copy(SEM)revealed a behaviour of fibre-matrix adhesion in untreated treated biocomposites.SEM observation revealed good dispersion of the fillers in PLA.Dynamic mechanical analysis revealed that C1P1A showed highest glass transition temperature(Tg)and storage modulus(E')while untreated C3P7 displayed the least Tg and E'.Overall findings showed that alkali-treated hybrid biocomposites(CF/PALF/PLA)especially C1P1A have improved flexural properties,dynamic and morphological properties over untreated biocomposites.Success of these findings will provide attracting consideration of these hybrid biocomposites for various lightweight uses in a broad selection of industrial applications such as biomedical sectors,automobile,construction,electronics equipment,and hardware tools.     

Folate: Metabolism,genes, polymorphisms and the associated diseases

Folate being an important vitamin of B Complex group in our diet plays an important role not only in the synthesis of DNA but also in the maintenance of methylation reactions in the cells. Folate metabolism is influenced by several processes especially its dietary intake and the polymorphisms of the associated genes involved. Aberrant folate metabolism, therefore, affects both methylation as well as the DNA synthesis processes, both of which have been implicated in the development of various diseases. This paper reviews the current knowledge of the processes involved in folate metabolism and consequences of deviant folate metabolism, particular emphasis is given to the polymorphic genes which have been implicated in the development of various diseases in humans, like vascular diseases, Down's syndrome, neural tube defects, psychiatric disorders and cancers.     

Curcumin and its synthetic analogue dimethoxycurcumin differentially modulates antioxidant status of normal human peripheral blood mononuclear cells

Curcumin is a polyphenol derived from the herb Curcuma longa, which has been extensively studied in terms of its antitumour, antioxidant, and chemopreventive activity as well as various other effects. In the present work we compared curcumin with its synthetic analogue dimethoxycurcumin (dimc) in terms of its antioxidant enzyme-modulating effects in human peripheral blood mononuclear cells (PBMC). We found that these compounds modulate antioxidant enzymes differentially. Both curcumin and dimethoxycurcumin effected a decrease in lipid peroxidation status in PBMC, however, curcumin had better activity in this regard. An increase in the activity of catalase was seen in the case of curcumin-treated PBMC, whereas dimc increased catalase activity significantly to almost twofold level. Real time-polymerase chain reaction (RT-PCR) analysis revealed significant up-regulation of catalase at mRNA level post treatment with curcumin as well as dimc, however, dimc had better activity in this regard. Glutathione reductase (GR) activity and reduced glutathione levels increased in the case of peripheral blood mononuclear cells (PBMC) treated with curcumin, however, the trend was reversed with dimethoxycurcumin where, both glutathione reductase activity and reduced glutathione levels were significantly reduced. RT-PCR analysis of glutathione reductase mRNA levels showed decrease in mRNA levels post treatment with dimethoxycurcumin (dimc) further corroborating GR enzyme assay results, however, we could not obtain significant result post curcumin treatment. NFkB reporter assay and western blot analysis of nuclear as well as cytosolic fractions of NFkB revealed that curcumin inhibits NFkB activation whereas inhibition was much less with dimc. It has been reported that curcumin and dimc exerts differential cytotoxicity in normal and tumour cells and the reason for this had been attributed to the differential uptake of these compounds by normal cells and tumour cells. Based on our results we propose that differential modulation of antioxidant enzymes via NFkB pathway could be the reason behind differential cytotoxicity of dimc as well as curcumin in normal cells and tumour cells in addition to differential uptake of these compounds as reported previously.     

Biochemical diversity evaluation in chickpea accessions employing mini-core collection

The seeds of chickpea provide an exceptional source of dietary proteins and is one of the important legumes in both developed and developing countries over the world. The available germplasm of cultivated chickpea is deficient in desired biochemical signatures. To identify new sources of variations for breeding, reduced subsets of germplasm such as mini-core collection can be explored as an effective resource. In the present investigation, mini-core collections consisting of 215 accessions of chickpea were extensively evaluated for tapping biochemical diversity. Analysis included ten biochemical parameters comprising total protein, total free amino acids, phytic acid, tannin, total phenolics, total flavonoids, lectin, DPPH radical scavenging activity, in vitro digestibility of protein and starch. The spectrum of diversity was documented for total protein (4.60–33.90%), total free amino acids (0.092–9.33 mg/g), phytic acid (0.009–4.06 mg/g), tannin (0.232–189.63 mg/g), total phenolics (0.15–0.81 mg/g), total flavonoids (0.04–1.57 mg/g), lectin (0.07–330.32 HU/mg), DPPH radical scavenging activity (26.74–49.11%), in vitro protein digestibility (59.45–76.22%) and in vitro starch digestibility (45.63–298.39 mg of maltose/g). The principal component analysis revealed association of chickpea higher protein content to the lower level of total phenolics and flavonoid contents. The dendrogram obtained by unweighted pair group method using arithmetic average cluster analysis grouped the chickpea accessions into two major clusters. This is the first comprehensive report on biochemical diversity analysed in the mini-core chickpea accessions. The ultimate purpose of conducting such studies was to deliver information on nutritional characteristics for effective breeding programmes. Depending on the objectives of the breeding aforesaid accessions could be employed as a parent.     

Measurement of Elastic Modulus of Collagen Type I Single Fiber

Collagen fibers are the main components of the extra cellular matrix and the primary contributors to the mechanical properties of tissues. Here we report a novel approach to measure the longitudinal component of the elastic moduli of biological fibers under conditions close to those found in vivo and apply it to type I collagen from rat tail tendon. This approach combines optical tweezers, atomic force microscopy, and exploits Euler-Bernoulli elasticity theory for data analysis. This approach also avoids drying for measurements or visualization, since samples are freshly extracted. Importantly, strains are kept below 0.5%, which appear consistent with the linear elastic regime. We find, surprisingly, that the longitudinal elastic modulus of type I collagen cannot be represented by a single quantity but rather is a distribution that is broader than the uncertainty of our experimental technique. The longitudinal component of the single-fiber elastic modulus is between 100 MPa and 360 MPa for samples extracted from different rats and/or different parts of a single tail. Variations are also observed in the fibril-bundle / fibril diameter with an average of 325±40 nm. Since bending forces depend on the diameter to the fourth power, this variation in diameter is important for estimating the range of elastic moduli. The remaining variations in the modulus may be due to differences in composition of the fibril-bundles, or the extent of the proteoglycans constituting fibril-bundles, or that some single fibrils may be of fibril-bundle size.     

Enhanced validation of small-molecule ligands and carbohydrates in the Protein Data Bank

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Glaucoma Pred: Glaucoma prediction based on Myocilin genotype and phenotype information

Glaucoma is the second leading cause of blindness after cataract and is heterogeneous in nature. Employing a genetic approach for the detection of the diseased condition provides an advantage that the gene responsible for the disease can be identified by genetic test. The availability of predictive tests based on the published literature would provide a mechanism for early detection and treatment. The genotype and phenotype information could be a valuable source for predicting the risk of the disease. To this end, a web server has been developed, based on the genotype and phenotype of myocilin mutation, which were identified by familial linkage analysis and case studies. The proposed web server provides clinical data and severity index for a given mutation. The server has several useful options to help clinicians and researchers to identify individuals at a risk of developing the disease. Glaucoma Pred server is available at http://bioserver1.physics.iisc.ac.in/myocilin.