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Plant-growth-promoting rhizobacteria (PGPR) help plants by increasing plant growth and defending them against pathogens and pests. There is considerable research supporting the use of these bacteria in plant pathogens management, but the number of research papers that have focused on their effect on insect pests control is quite few. In this research, we examined the ability of four native strains of Pseudomonas fluorescens to manage the cotton aphid, Aphis gossypii, on greenhouse-grown cucumbers in Iran. The strains UTPF (University of Tehran Pseudomonas fluorescens) 68, UTPF1, UTPF6 and PF169 of P. fluorescens were used as seed treatment to evaluate their impact on both cucumber growth and cotton aphid population growth parameters. The strains UTPF68 and PF169 of this bacterium influenced phenology of cucumber by decreasing the Growing Degree Days of flowering period. Also, the plants treated with these bacterial strains had a significant increase in yield weight of approximately 58%. In the other part ...

In the preparation of nanocomposites, there is competition between the dispersion of nanoparticles and the formation of agglomerates. In this study, radical copolymerization of ethyl acrylate and methyl methacrylate initiated by 2,2‐azobis (isobutyro) nitrile (AIBN) was performed, in the presence of titanium oxide (TiO2) nanoparticles modified in a new approach; a good dispersion of the nanoparticles in the unsaturated polyester (UP) matrix was obtained. The TiO2 nanoparticles were exposed to 3‐(methacryloxy) propyl trimethoxy silane as the coupling agent. The presence of coupling agent‐grafted TiO2 nanoparticles in the copolymerization process resulted in the formation of a polymeric layer on the surface of the TiO2 nanoparticles (doubly modified‐TiO2). The grafting of coupling agent molecules and consequently copolymer macromolecular chains onto the surface of TiO2 nanoparticles was investigated using Fourier transform infrared (FTIR) analysis. It found that the formation of an acrylate layer on the sur...

Catalytic amounts of heteropoly acids and polyoxometalates promoted mononitration of phenolic compounds using iron(III) nitrate nonahydrate and bismuth(III) nitrate pentahydrate in dichloromethane at room temperature. Tungstophosphoric acid cesium salt, Cs2.5H0.5PW12O40, in a heterogeneous phase, exhibited significant rate enhancement of reactions as well as ortho selectivity without over-nitration and oxidation byproducts.

The rice green semi looper, Naranga aenescens Moore (Lepidoptera: Noctuidae) causes severe damage to rice fields in Eastern Asia and Middle East. We demonstrate that two types of serine proteases are active in the midgut of the third instar larvae of N. aenescens, but trypsin-like proteases are considerably more active than chymotrypsin-like proteases. To develop better control strategies, purification and biochemical characterization of a major trypsin-like digestive protease from the midgut of the third instar larvae of N. aenescens was achieved by gel filtration and anion exchange chromatography. After the final purification step, the enzyme was purified 9.62-fold with a recovery of 16.1% and a specific activity of 4.12 U/mg protein and a molecular mass of approximately 88.5 kDa. Biochemical characterization indicated that the purified protease had highest activity at pH 10 and 30°C and was stable for up to 6 h under those conditions. Divalent cations, especially Ca2+, Mg2+, and Cu2+, increased the enzyme activity and synthetic inhibitors that target trypsin-like activity caused a significant reduction in caseinolytic activity. These data may be used to develop inhibitors that decrease the damage of N. aenescens to rice cultivars in the field.

Ca2+ dependent exocytosis inParamecium involves the release of numerous secretory organelles known as “trichocysts”. According toGarofalo et al. (1983) trichocysts pass through three stages of condensed (tmxI), partially expanded (stage II) before release, and fully expanded (stage III) or released trichocysts. We have therefore investigated the effect of two widely used Ca2+ channel blockers, verapamil and nifedipine and the muscular relaxant, dantrolene-Na, on the process of trichocyst release. Verapamil and nifedipine inhibited secretion in a dose dependent manner, but dantrolene-Na and the solvent, PEG-400, did not abolish it. Electron microscopic study of preincubatedParamecium cells in verapamil resulted in the appearance of tmxI, whereas untreated controls remained in partially expanded stage II. Pretreatment of isolated membrane free trichocysts with verapamil did not inhibit matrix expansion in the presence of increasing Ca2+ concentration. In a separate experiment, cells were pretreated with verapamil and the anti calmodulin compound, trifluoperazine. The cells were then induced to release their secretory contents by picric acid-Ca2+ treatment. Electron microscopic examination of cells captured by quick fixation with osmium tetroxide revealed that verapamil treated cells manifested the inhibition of membrane fusion, whereas in TFP treated cells there was no sign of a traceable exocytotic opening formation after membrane fusion. Based on present results we propose a role for calmodulin in the formation of exocytotic openings.