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51.
Patring JD Jastrebova JA Hjortmo SB Andlid TA Jägerstad IM 《Journal of agricultural and food chemistry》2005,53(7):2406-2411
A simplified HPLC method for rapid determination of folates in yeast with ultraviolet and fluorescence detection without sample purification has been developed. By use of the column Aquasil C(18), specially designed for polar analytes, and gradient elution, it was possible to separate and determine five folate derivatives: tetrahydrofolate, 5-methyltetrahydrofolate, and 5-formyltetrahydrofolate with fluorescence detection, and 10-formylfolic acid and folic acid with ultraviolet detection. The sample preparation required only a small amount of dry yeast (25-50 mg) and included an extraction of folates by heat treatment and deconjugation of folate polyglutamates to monoglutamates with the use of rat serum conjugase. Validation involved investigation of matrix effects, determination of recovery by standard addition method, repeatability, and stability tests. The dominating folate forms in commercial dry baker's yeast were found to be tetrahydrafolate and 5-methyltetrahydrofolate with a total folate content of 2890 microg/100 g (63.4 nmol/g). The simplicity of the method makes it suitable for folate screening studies of different yeast strains. 相似文献
52.
Milisavljević MDj Konstantinović MM Brkljacić JM Maksimović VR 《Journal of agricultural and food chemistry》2005,53(6):2076-2080
Using the modified rapid amplification of cDNA ends (5'-RACE) approach, a fragment containing the 955 bp long 5'-regulatory region of the buckwheat storage globulin gene (FeLEG1) has been amplified from the genomic DNA of buckwheat. The entire fragment was sequenced, and the sequence was analyzed by computer prediction of cis-regulatory elements possibly involved in tissue-specific and developmentally controlled seed storage protein gene expression. The promoter obtained might be interesting not only for fundamental research but also as a useful tool for biotechnological application. 相似文献
53.
Milica B. Velimirovi? Miljana Dj. Prica Bo?o D. Dalmacija Sr?an D. Ron?evi? Milena B. Dalmacija Milena Dj. Be?eli? Jelena S. Tri?kovi? 《Water, air, and soil pollution》2011,214(1-4):219-229
The behavior of metals in sediments after their disposal to land has important implications for the environmental management. The sediment from the Carska Bara (Serbia) was polluted with adequate metal salts in order to reach severe contamination based on the pseudo-total metal content of Pb, Cd, Ni, Zn, Cu, and Cr according to the corresponding Dutch standards and Canadian guidelines. The toxicity and fate of the metal in sediment depend on its chemical form, and therefore, quantification of the different forms of a metal is more meaningful than the estimation of its total concentration. In this study, fractionation of metals in sediment has been investigated to determine its speciation and ecotoxic potential, as well as evaluation of metal potential toxicity based on the simultaneously extracted metals (SEMs) and acid volatile sulfides (AVSs) analysis at the beginning of the experiment and after 5?weeks of sediment aging. The investigations suggest that Cd, Pb, and Zn have a tendency to associate with labile fraction, the most mobile and most dangerous fraction for the environment. Risk assessment code revealed their high risk. Copper and chromium showed low to medium risk to the aquatic environment. Nickel showed no risk to the aquatic environment. This was the case at the beginning and after 5?weeks of aging. Aging yielded an increased mobility of all metals based on the increased proportion in mobile fractions. The ??[SEM i ]/[AVS] ratio was found to be >1 both at the beginning and after 5?weeks of aging, with the ratio showing an increase with time. This ratio indicates the potential availability/toxicity and, according to the US EPA criteria, the samples belong to the group with probable negative effect. If particular metals are considered, only the ??[SEM i ]/[AVS] ratio for zinc was >1 at the beginning. After 5?weeks, the ratio was >1 for zinc, lead, and copper. Comparison of the results of sequential extraction and the results of SEM and AVS analysis showed good agreement for lead and zinc. 相似文献
54.
Wild P Farhan H McEwan DG Wagner S Rogov VV Brady NR Richter B Korac J Waidmann O Choudhary C Dötsch V Bumann D Dikic I 《Science (New York, N.Y.)》2011,333(6039):228-233
Selective autophagy can be mediated via receptor molecules that link specific cargoes to the autophagosomal membranes decorated by ubiquitin-like microtubule-associated protein light chain 3 (LC3) modifiers. Although several autophagy receptors have been identified, little is known about mechanisms controlling their functions in vivo. In this work, we found that phosphorylation of an autophagy receptor, optineurin, promoted selective autophagy of ubiquitin-coated cytosolic Salmonella enterica. The protein kinase TANK binding kinase 1 (TBK1) phosphorylated optineurin on serine-177, enhancing LC3 binding affinity and autophagic clearance of cytosolic Salmonella. Conversely, ubiquitin- or LC3-binding optineurin mutants and silencing of optineurin or TBK1 impaired Salmonella autophagy, resulting in increased intracellular bacterial proliferation. We propose that phosphorylation of autophagy receptors might be a general mechanism for regulation of cargo-selective autophagy. 相似文献
55.
An organosilicon cage compound containing the sila-adamantane structural unit, which is the building block of crystalline silicon, was synthesized by the Lewis acid-catalyzed rearrangement reaction of a structural isomer. 相似文献
56.
Fushman I Englund D Faraon A Stoltz N Petroff P Vuckovic J 《Science (New York, N.Y.)》2008,320(5877):769-772
Optical nonlinearities enable photon-photon interaction and lie at the heart of several proposals for quantum information processing, quantum nondemolition measurements of photons, and optical signal processing. To date, the largest nonlinearities have been realized with single atoms and atomic ensembles. We show that a single quantum dot coupled to a photonic crystal nanocavity can facilitate controlled phase and amplitude modulation between two modes of light at the single-photon level. At larger control powers, we observed phase shifts up to pi/4 and amplitude modulation up to 50%. This was accomplished by varying the photon number in the control beam at a wavelength that was the same as that of the signal, or at a wavelength that was detuned by several quantum dot linewidths from the signal. Our results present a step toward quantum logic devices and quantum nondemolition measurements on a chip. 相似文献
57.
Jelena Tomić Marijana Pešaković Jasminka Milivojević Žaklina Karaklajić-Stajić 《Journal of plant nutrition》2013,36(16):2009-2021
The main objective of this study was to investigate and compare the effects of fertilizer types on the counts of soil microorganisms, the mineral leaf composition, and productivity of three strawberry cultivars in the period 2012–2013. Two types of fertilizers were applied—mineral and microbiological. Significantly higher number of Azotobacter, ammonifiers, oligonitrophils, and total microbial count were observed under biofertilizers treatment. Significantly higher counts of fungi and actinomycetes were obtained under mineral fertilizer treatment, compared to other fertilizer treatments. The use of mineral fertilizer led to the most favorable balance of macronutrients and micronutrients in the leaf. In 2012, the generative potential and yield increased after mineral fertilization, whereas in 2013 these parameters were positively affected by mineral fertilizer and Biofertilizer 1. Given the obtained results, in order to improve technology of strawberry production, a partial substitution of mineral fertilizers by microbiological ones can be recommended. 相似文献
58.
Jelena?Vasiljevi? Marija?Gorjanc Ivan?Jerman Brigita?Tom?i? Martina?Modic Miran?Mozeti? Boris?Orel Barbara?Simon?i?Email author 《Fibers and Polymers》2016,17(5):695-704
Oxygen plasma pre-treatment was applied to cotton fabric with the aim of improving the water repellency performance of an inorganic-organic hybrid sol-gel perfluoroalkyl-functionalized polysilsesquioxane coating. Cotton fabric was pre-treated with low-pressure oxygen plasma for different treatment times and operating powers. Afterward, 1H,1H,2H,2H-perfluorooctyltriethoxysilane (SiF) was applied to the cotton fabric samples using the pad-dry-cure method. The surfaces of the untreated and modified cotton fibers were characterised using Fourier transform infrared spectroscopy, Xray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The water repellency of the SiF-coated fabric samples was evaluated using static and sliding contact angle measurements with water. The results show that the plasma treatment with the shortest treatment time (10 s) and the lowest operating current (0.3 A) increased the atomic oxygen/carbon ratio of the cotton fiber surface from 0.6 to 0.8 and induced the formation of a nano-sized grainy surface. Increasing the plasma treatment time and/or operating current did not intensify the surface changes of the cotton fibers. Such saturation effects were explained by the large influence of reactive oxygen atoms during the plasma treatment. The measured static water contact angles on the surface of the untreated and plasma pre-treated and SiF-coated cotton fabrics showed that the oxygen plasma pre-treatment enabled the increase of the water contact angle from 135° to ≈150°, regardless of the applied plasma treatment time and discharge power. This improvement in the hydrophobicity of the SiF coating was followed by a decrease in the sliding angle of water droplets by more than 10° compared to the plasma untreated and SiF-coated sample characterized by a water sliding angle of 45°. Additionally, measurements of the water sliding angle revealed that the increase of the static contact angle from 149° to 150° corresponded to a drop of the water sliding angle from 33 to 24°, which suggests that the plasma pre-treatment of 20 s at an operating current of 0.3 A produced the best water-repellent performance of the SiF-coated cotton fabric. 相似文献
59.
Ivana Potočnik Jelena Vukojević Mirjana Stajić Emil Rekanović Miloš Stepanović Svetlana Milijašević Biljana Todorović 《Crop Protection》2010
Twenty Cladobotryum dendroides isolates from Serbian Agaricus bisporus farms collected during 2003–2007, and the F56 strain of A. bisporus were tested in vitro for sensitivity to tea tree oil (Timorex 66 EC), a biofungicide, in comparison with prochloraz–manganese (Octave WP). The efficacies of tea tree oil and prochloraz–manganese were evaluated in a mushroom growing room, after application at standard product application rates and a combination of the two at respective proportion of 20:80%. Tea tree oil was considerably less toxic than prochloraz–manganese in vitro to C. dendroides isolates (ED50 112.9–335.8 mg l−1) and A. bisporus F56 strain (98.0 mg l−1), although neither fungicide was lethal to the pathogen. The biological efficiency of tea tree oil was higher than in treatments with the reference formulation of prochloraz–manganese. In our in vivo trials, no negative interference of the biofungicide with A. bisporus physiology was observed. Tea tree oil applied at the standard product application rate caused a significant reduction in cobweb disease levels in the A. bisporus growing room. Timorex 66 EC should be tested further in combination with other biofungicides to investigate the effectiveness of various mixtures for A. bisporus disease control. 相似文献