Revealing contrasting genetic variation and study of genetic diversity in urdbean (Vigna mungo (L.) Hepper) using SDS-PAGE of seed storage proteins

Total seed storage protein profiles of 20 urdbean genotypes including the popular variety T9 were analysed by Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). 14 genotypes could be clearly identified based on genotype-specific seed protein fingerprints while rest of the test genotypes were categorized into three protein types. Dendrogram based on electrophoretic data clustered the genotypes into seven groups at 78.5% phenon level.  TU 95-1 with TU 12-25-4 revealed lowest similarity index value (0.33) followed by TU 95-1 with PU 30 and KU 96-3(SI=0.35). Clustering pattern revealed distinctly divergent group formed by TPU 95-1 and TPU 4. These may serve as a valuable source genotype in recombination breeding.   Key words: Seed storage protein profiling, SDS-PAGE, Genetic variation, urdbean

Identification of seed storage protein markers for drought tolerance in mungbean

A set of 292 mungbean germplasm accessions including 62 popularly adapted local land races and two wild forms (Vigna radiata var. sublobata), important breeding lines and standard ruling varieties were screened for drought stress tolerance at seedling stage.  Eight genotypes e.g., C. No. 35, OUM 14-1, OUM 49-2, Pusa 9072, OM 99-3, Banapur local B, Nipania munga, Kalamunga 1-A) have been identified to possess drought tolerance.  Globulin seed storage protein profiling was carried out in 19 selected mungbean genotypes comprising eight drought tolerant, seven drought sensitive, two wild forms of mungbean (TCR 20 and TCR 213) and two standard checks (LGG 460 and T 2-1) to explore differentially expressed polypeptides. Seed protein profiles revealed 15 scorable polypeptide bands with molecular weights ranging from 10.0 to 102.2kD. A specific 12.8kD polypeptide band was present in all above drought tolerant test genotypes including the wild accession TCR 20. Such a polypeptide band may serve as useful biochemical marker for identification of drought tolerant genotypes in mungbean.             Key words: Genetic diversity, seed storage protein profile, wild and cultivated Vigna radiata

Globulin seed storage protein based genotyping and Study of genetic diversity in core accessions of mungbean under drought stress

Globulin seed storage protein profiles of 19 mungbean genotypes including two wild forms of Vigna radiata var. sublobata(TCR 20 and TCR 213) and two standard  checks(T 2-1 and LGG 460) were analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Thirteen genotypes could be clearly identified based on genotype-specific seed protein fingerprints. The combined dendrogram showed six genetic clusters within 68% phenon level. The clustering based on the combined clustering analysis revealed discrimination of all test genotypes even immediately beyond 88% phenon level, whereas individual clustering analysis based on protein and agro-morphological level failed to do so. Nipania munga, TCR 213, T 2-1, LGG 460, TCR 20 and Banapur local B were identified to be highly divergent genotypes. TCR 20 appears to have more genetic proximity to the mungbean genotypes than TCR 213. T 2-1, LGG 460 and TCR 20 are potentially high yielding. These may serve as valuable materials for recombination breeding in mungbean

Preparation of nanodimensional CdS by chemical dipping technique and their characterization

A simple and cost effective chemical technique has been utilized to grow cadmium sulphide (CdS) nanoparticles at room temperature. The sample is characterized with XRD (X-ray diffractometer), SEM (Scanning electron microscope), TEM (Transmission electron microscope) and UV-VIS spectrophotometer. The particle size estimated using X-ray line broadening method is approximately 5 nm. Instrumental broadening was taken into account while particle size estimation. The lattice strain was evaluated using Williamson-Hall equation. SEM illustrates formation of sub-micron size crystallites and TEM image gives particle size approximately between 4-5 nm. Optical absorption study exhibits a band gap energy value of about 2.6 eV

Photoswitching and thermoresponsive properties of conjugated multi-chromophore nanostructured materials

Conjugated multi-chromophore organic nanostructured materials have recently emerged as a new class of functional materials for developing efficient light-harvesting, photosensitization, photocatalysis, and sensor devices because of their unique photophysical and photochemical properties. Here, we demonstrate the formation of various nanostructures (fibers and flakes) related to the molecular arrangement (H-aggregation) of quaterthiophene (QTH) molecules and their influence on the photophysical properties. XRD studies confirm that the fiber structure consists of >95% crystalline material, whereas the flake structure is almost completely amorphous and the microstrain in flake-shaped QTH is significantly higher than that of QTH in solution. The influence of the aggregation of the QTH molecules on their photoswitching and thermoresponsive photoluminescence properties is revealed. Time-resolved anisotropic studies further unveil the relaxation dynamics and restricted chromophore properties of the self-assembled nano/microstructured morphologies. Further investigations should pave the way for the future development of organic electronics, photovoltaics, and light-harvesting systems based on π-conjugated multi-chromophore organic nanostructured materials

Microstructural changes and effect of variation of lattice strain on positron annihilation lifetime parameters of zinc ferrite nanocomposites prepared by high enegy ball-milling

Zn-ferrite nanoparticles were synthesized at room temperature by mechanical alloying the stoichiometric (1:1 mol%) mixture of ZnO and α-Fe2O3 powder under open air. Formation of both normal and inverse spinel ferrite phases was noticed after 30 minutes and 2.5 hours ball milling respectively and the content of inverse spinel phase increased with increasing milling time. The phase transformation kinetics towards formation of ferrite phases and microstructure characterization of ball milled ZnFe2O4 phases was primarily investigated by X-ray powder diffraction pattern analysis. The relative phase abundances of different phases, crystallite size, r.m.s. strain, lattice parameter change etc. were estimated from the Rietveld powder structure refinement analysis of XRD data. Positron annihilation lifetime spectra of all ball milled samples were deconvoluted with three lifetime parameters and their variation with milling time duration was explained with microstructural changes and formation of different phases with increase of milling time duration

Size Tunable Cesium Antimony Chloride Perovskite Nanowires and Nanorods

All-inorganic perovskite nanocrystals are emergent alternative of organolead halide perovskites. Cesium antimony halide (Cs₃Sb₂X₉, X = Cl, Br, I) all-inorganic perovskites nanocrystals possessing analogous electronic configuration to the organolead halide perovskites are promising materials for optoelectronic applications. We report on a colloidal route to synthesis uniform Cs₃Sb₂Cl₉ perovskite nanowires with lengths up to several microns. We have synthesized aspect ratio controlled nanorods with the same ∼20 nm diameter of nanowires by tuning the precursors and ligands in the reaction. The crystallinity of the nanocrystals is significantly altered from the pristine bulk trigonal and orthorhombic phases owing to the one-dimensional shape of the nanocrystals. Rietveld refinement carefully separates out orthorhombic phase from the trigonal phase revealing a coexistence of both the phases in a minor and major ratio in the nanocrystals. The functionality in the form of fast photodetector demonstrates Cs₃Sb₂Cl₉ nanocrystals as promising materials for optoelectronic applications

Influence of size and shape on the photocatalytic properties of SnO<SUB>2</SUB> nanocrystals

Tuning the functional properties of nanocrystals is an important issue in nanoscience. Here, we are able to tune the photocatalytic properties of SnO<SUB>2</SUB> nanocrystals by controlling their size and shape. A structural analysis was carried out by using X-ray diffraction (XRD)/Rietveld and transmission electron microscopy (TEM). The results reveal that the number of oxygen-related defects varies upon changing the size and shape of the nanocrystals, which eventually influences their photocatalytic properties. Time-resolved spectroscopic studies of the carrier relaxation dynamics of the SnO<SUB>2</SUB> nanocrystals further confirm that the electron–hole recombination process is controlled by oxygen/defect states, which can be tuned by changing the shape and size of the materials. The degradation of dyes (90 %) in the presence of SnO<SUB>2</SUB> nanoparticles under UV light is comparable to that (88 %) in the presence of standard TiO<SUB>2</SUB> Degussa P-25 (P25) powders. The photocatalytic activity of the nanoparticles is significantly higher than those of nanorods and nanospheres because the effective charge separation in the SnO2 nanoparticles is controlled by defect states leading to enhanced photocatalytic properties. The size- and shape-dependent photocatalytic properties of SnO<SUB>2</SUB> nanocrystals make these materials interesting candidates for photocatalytic applications