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Temperature, strain rate, and defects are important considerations in determining the mechanical properties of materials. The mechanical properties of nanocrystalline copper-tantalum (Cu-Ta) alloy are investigated using classical molecular dynamics simulation approach in which embedded atom method of potential with periodic boundary conditions in all directions has been adopted. Numerical simulation has been performed to predict the mechanical properties of nanocrystalline copper-tantalum alloy. The virtual tensile test has been conducted at a fixed strain rate and increasing temperature where the discreet change in temperature from 50 to 1600 K has been used as a controlling parameter. The strain rate is fixed in the direction of the principal crystallographic planes and has not been affected by the change in temperature. The mechanical properties of the Cu-Ta nanocrystalline alloy such as yield strength, ultimate strength, and Young's modulus are observed. Further, simulations are carried out to analyze the vacancy formation energy with vacancy concentration and potential energy response at discrete temperatures. Nanocrystalline Cu-Ta alloy is observed to be more susceptible to failure at high temperatures. Particularly at 300 K, the strength of nanocrystalline Cu-Ta is 6 GPa which decreases to 4 GPa at 1200 K.

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Montmorillonite K10 (MMT K10) supported copper oxide nanoparticles (CuONPs) were synthesized by incorporating CuONPs onto the surface of MMT K10 by reducing the metal precursor with the help of hydrazine hydrate. Effects of various factors on the efficiency of composite to remove hexavalent chromium were studied to find out the optimum conditions for maximum removal. Under optimum conditions 15 mg of the synthesized nanocomposite was found capable to almost completely remove (99.9 %) hexavalent chromium in 30 min from a 10 ppm aqueous chromium solution and that too in a wide range of pH from 2.88 to 5.56. The synthesized MMT K10 supported CuONPs were characterized by UV, SEM-EDX, FTIR and XRD studies. The average particle size of supported CuONPs was found to be 22.9 nm. Antibacterial potential of the prepared composite was also studied for one Gram-positive bacterium Staphylococcus aureus (ATCC 25323) and one Gram-negative bacterium Pseudomonas aeruginosa (ATCC 27853). The prepared nanocomposite was found to have excellent bactericidal potential and its statistical analysis was performed using t-test which indicates both bacterial strains of Pseudomonas aeruginosa and Staphylococcus aureus show different zone of inhibition for different concentrations.

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Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, secretes a number of effectors through a type 3 secretion system. One of these effectors, called XopQ, is required for virulence and suppression of rice innate immune responses induced by the plant cell-wall-degrading enzyme lipase/esterase A (LipA). Bioinformatic analysis suggested that XopQ is homologous to inosine-uridine nucleoside hydrolases (NH). A structural model of XopQ with the protozoan Crithidia fasciculata purine NH suggested that D116 and Y279 are potential active site residues. X. oryzae pv. oryzae xopQ mutants (xopQ-/pHM1::xopQD116A and xopQ-/pHM1::xopQY279A) show reduced virulence on rice compared with xopQ-/pHM1::xopQ. The two predicted XopQ active site mutants (xopQ-/pHM1::xopQD116A and xopQ-/pHM1::xopQY279A) exhibit a reduced hypersensitive response (HR) on Nicotiana benthamiana, a nonhost. However, Arabidopsis lines expressing either xopQ or xopQY279A are equally proficient at suppression of LipA-induced callose deposition. Purified XopQ does not show NH activity on standard nucleoside substrates but exhibits ribose hydrolase activity on the nucleoside substrate analogue 4-nitrophenyl ß-D-ribofuranoside. The D116A and Y279A mutations cause a reduction in biochemical activity. These results indicate that mutations in the predicted active site of XopQ affect virulence and induction of the HR but do not affect suppression of innate immunity.

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Innate immune responses are induced in plants and animals through perception of Damage Associated Molecular Patterns. These immune responses are suppressed by pathogens during infection. A number of studies have focussed on identifying functions of plant pathogenic bacteria that are involved in suppression of Pathogen Associated Molecular Pattern induced immune responses. In comparison, there is very little information on functions used by plant pathogens to suppress Damage Associated Molecular Pattern induced immune responses. Xanthomonasoryzae pv. oryzae, a gram negative bacterial pathogen of rice, secretes hydrolytic enzymes such as LipA (Lipase/Esterase) that damage rice cell walls and induce innate immune responses. Here, we show that Agrobacterium mediated transient transfer of the gene for XopN, a X. oryzae pv. oryzae type 3 secretion (T3S) system effector, results in suppression of rice innate immune responses induced by LipA. A xopN (-) mutant of X. oryzae pv. oryzae retains the ability to suppress these innate immune responses indicating the presence of other functionally redundant proteins. In transient transfer assays, we have assessed the ability of 15 other X. oryzae pv. oryzae T3S secreted effectors to suppress rice innate immune responses. Amongst these proteins, XopQ, XopX and XopZ are suppressors of LipA induced innate immune responses. A mutation in any one of the xopN, xopQ, xopX or xopZ genes causes partial virulence deficiency while a xopN (-) xopX (-) double mutant exhibits a greater virulence deficiency. A xopN (-) xopQ (-) xopX (-) xopZ (-) quadruple mutant of X. oryzae pv. oryzae induces callose deposition, an innate immune response, similar to a X. oryzae pv. oryzae T3S(-) mutant in rice leaves. Overall, these results indicate that multiple T3S secreted proteins of X. oryzae pv. oryzae can suppress cell wall damage induced rice innate immune responses.

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A bacterial strain, Streptomyces sp. CIMAP- A1 was isolated from Geranium rhizosphere and identified by morphological, physiological, biochemical and molecular characters (16S rDNA gene sequence). Phylogenetically, it was found most closely related to S. vinacendrappus, strain NRRL-2363 with 99% sequence similarity. The strain had potential antagonistic activity (in vitro) against wide range of phytopathogenic fungi like Stemphylium sp., Botrytis cinerea, Sclerotinia sclerotiorum, Colletotrichum spp., Curvularia spp., Corynespora cassicola and Thielavia basicola. The extracellular secondary metabolites produced by the strain in the culture filtrates significantly inhibited the spore germination, growth of germ tube of the germinated spores and radial growth of Alternaria alternata, Colletotrichum acutatum, Curvularia andropogonis and Fusarium moniliforme. The extraction of culture filtrate with solvents and purification by following VLC and PTLC methods always yielded a 10th fraction antifungal compound showing activity against wide range of phytopathogenic fungi. The strain was able to produce siderophores and indole-3-acetic acid. The strain was found to enhance the growth and biomass production of Geranium. It increased 11.3% fresh shoot biomass of Geranium and 21.7% essential oil yield.

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A sensitive, rapid, simple, and accurate high performance thin layer chromatographic method has been developed to standardize the bark of Grewia tiliaefolia Vahl. (Family: Tiliaceae) using betulin as an analytical marker. Chloroform extracts of bark from five different sources were used for HPTLC on silica gel with toluene-ethyl acetate, 90 + 10 v/v, as mobile phase. Under these conditions, the Rf of betulin was 0.22. The calibration plot was linear in the range of 1000 ng to 1800 ng of betulin and the correlation coefficient, 0.999, was indicative of good linear dependence of peak area on concentration. The mean assay of betulin was 2.596 +/- 0.594 mg g(-1) of bark. The method permits reliable quantification of betulin and good resolution and separation of betulin from other constituents of Grewia tiliaefolia. Recovery values from 96.09 to 98.87% showed that the reliability and reproducibility of the method were excellent. The proposed HPTLC method for quantitative monitoring of betulin in Grewia tiliaefolia can be used for routine quality testing.

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Plants containing flavonoids have been reported to possess strong antioxidant properties. The ethanolic extract of Striga orobanchioides was screened for in vitro and in vivo antioxidant properties using standard procedures. The ethanol extract exhibited IC(50) values of 18.65+/-1.46 and 11.20+/-0.52 micro g/ml, respectively in DPPH and nitric oxide radical inhibition assays. These values were less than those obtained for ascorbic acid and rutin, used as standards. In the in vivo experiments the extract treatment at 100mg/kg body weight dose caused a significant increase in the level of the catalase in the liver and the kidneys. A significant increase in the level of SOD in the liver was observed. The treatment also caused a significant decrease in the TBA-RS and increase in the ascorbic acid levels. These results suggest strong antioxidant potentials of the ethanolic extract of S. orobanchioides.

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