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121.
A methanol extract of the pod surfaces of Cajanus cajan, a feeding stimulant for fifth-instar Helicoverpa armigera, was shown to contain four main phenolic compounds. Three of these were identified as isoquercitrin, quercetin, and quercetin-3-methyl ether, by comparing UV spectra and HPLC retention times with authentic standards. The fourth compound was isolated by semipreparative HPLC and determined to be 3-hydroxy-4-prenyl-5- methoxystilbene-2-carboxylic acid (stilbene) by NMR spectroscopy and mass spectrometry. Quercetin, isoquercitrin, and quercetin-3-methyl did not affect the selection-behavior of fifth-instar H. armigera. However, larvae were deterred from feeding on glass-fiber disks impregnated with the stilbene. Furthermore, larvae exposed to quercetin-3-methyl ether consumed significant amounts of both disks. In a binary-choice bioassay, a combination of quercetin-3-methyl ether and the stilbene on one disk and pure quercetin-3-methyl ether on the other disk resulted in increased consumption of both glass-fiber disks by larvae. In contrast, consumption was reduced if the combination was presented to larvae on one disk with purified stilbene on the other disk. Cajanus cajan cultivars that varied in their susceptibility to H. armigera were surveyed for the presence of the four phenolic compounds. An absence of quercetin and higher concentrations of isoquercitrin than the cultivated variety characterized pod surface extracts of pod-borer-resistant cultivars. In addition, the ratio of the stilbene to quercetin-3-methyl ether was greater in the pod-borer-resistant cultivars. These findings are discussed in relation to the identification of chemical characters that can be used for crop improvement. 相似文献
122.
Relationship between nutritional composition of plant species and infestation levels of thrips 总被引:6,自引:0,他引:6
Levels of soluble protein and carbohydrate (raffinose, sucrose, glucose, and fructose) in leaves from a selection of plant species were measured to determine if a relationship existed between these nutrients and infestation by Frankliniella occidentalis and Heliothrips haemorrhoidalis. Most species of host plant examined contained a higher proportion of protein than carbohydrates, and overall, leaves from species of plants that supported populations of thrips had greater levels of protein than leaves from nonhost species. New leaves and flowers that supported F. occidentalis contained high levels of carbohydrate and protein. The quantity of protein in leaves at the top of the tree, Peumus boldus, was greater than in leaves from lower levels, and the amount of feeding damage accrued by H. haemorrhoidalis was greater on the upper foliage than lower foliage. Oviposition by H. haemorrhoidalis was positively correlated to levels of protein in host plants but not to levels of carbohydrates. Overall, levels of soluble protein in plants influenced their susceptibility to thrips more than levels of carbohydrates. 相似文献
123.
Heterogeneous enantioselective alkylation of benzaldehyde with diethylzinc was performed using (-)-ephedrine grafted on mesoporous
micelle templated aluminosilicates or silicates, as chiral auxiliary. Supports were characterized by a regular mesoporosity
and a same initial pore diameter. Immobilization of the chiral aminoalcohol was performed through covalent anchoring of 3-halogenopropyltrimethoxysilane
(XPTMS) and substitution of the halogen by (-)-ephedrine. Comparison of the efficiency of the catalysts was carried out. Results
were analyzed taking into account the accessibility to the catalytic sites by changing their density (decrease of XPTMS concentration,
spacing of the sites by alkyl goups) and the effect of the uncovered mineral surface on activities and enantioselectivities.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
124.
Monique K.-K. Figueiredo Rodrigo P.B. Costa-Felix Luis E. Maggi André V. Alvarenga Gilberto A. Romeiro 《Fuel》2012,91(1):209-212
Hydrous ethanol is a worldwide used biofuel. According to Brazilian regulations, the concentration of ethanol in hydrous ethanol can be accepted at a maximum concentration of 93.8% and a minimum of 92.6% by mass. The aim of this study is to identify the possible changes in hydrous ethanol fuel using ultrasonic attenuation and propagation velocity. The experiments were performed in the Laboratory of Ultrasound of the Brazilian National Institute of Metrology (Inmetro). The experiments and uncertainties in the methodology were evaluated according to the Guide to the Expression of Uncertainty in Measurement, JCGM 100:2008. The test samples used in this study were mixtures of ethanol and water with ethanol concentrations varying from 89.84% to 93.71% by mass; and a commercial fuel ethanol bought from a local distributor. The correlation coefficient between ethanol concentrations and ultrasonic propagation velocity was 0.99 (in modulus), and the maximum combined uncertainty was 0.60 m s?1. Considering attenuation, the correlation coefficient was 0.97, and the maximum combined uncertainty was 0.085 dB cm?1. However, its signal is not stable resulting an unreliable parameter. Within the tested concentration range, the highest concentration that is statistically different (p < 0.002, α = 5%) from 92.60% is 92.25%, considering propagation velocity as parameter. To validate the methodology, a commercial ethanol fuel was tested using the proposed method as well as the gas chromatography analytical method (gold standard). Result was statistically identical for propagation velocity when compared to the gold standard. 相似文献
125.
Galectin‐3‐Binding Glycomimetics that Strongly Reduce Bleomycin‐Induced Lung Fibrosis and Modulate Intracellular Glycan Recognition 下载免费PDF全文
Dr. Tamara Delaine Dr. Patrick Collins Dr. Alison MacKinnon Dr. G. Sharma John Stegmayr Dr. Vishal K. Rajput Dr. Santanu Mandal Dr. Ian Cumpstey Dr. Amaia Larumbe Dr. Bader A. Salameh Barbro Kahl‐Knutsson Dr. Hilde van Hattum Dr. Monique van Scherpenzeel Prof. Roland J. Pieters Prof. Tariq Sethi Dr. Hans Schambye Prof. Stina Oredsson Prof. Hakon Leffler Assoc. Prof. Helen Blanchard Prof. Ulf J. Nilsson 《Chembiochem : a European journal of chemical biology》2016,17(18):1759-1770
Discovery of glycan‐competitive galectin‐3‐binding compounds that attenuate lung fibrosis in a murine model and that block intracellular galectin‐3 accumulation at damaged vesicles, hence revealing galectin‐3–glycan interactions involved in fibrosis progression and in intracellular galectin‐3 activities, is reported. 3,3′‐Bis‐(4‐aryltriazol‐1‐yl)thiodigalactosides were synthesized and evaluated as antagonists of galectin‐1, ‐2, ‐3, and ‐4 N‐terminal, ‐4 C‐terminal, ‐7 and ‐8 N‐terminal, ‐9 N‐terminal, and ‐9 C‐terminal domains. Compounds displaying low‐nanomolar affinities for galectins‐1 and ‐3 were identified in a competitive fluorescence anisotropy assay. X‐ray structural analysis of selected compounds in complex with galectin‐3, together with galectin‐3 mutant binding experiments, revealed that both the aryltriazolyl moieties and fluoro substituents on the compounds are involved in key interactions responsible for exceptional affinities towards galectin‐3. The most potent galectin‐3 antagonist was demonstrated to act in an assay monitoring galectin‐3 accumulation upon amitriptyline‐induced vesicle damage, visualizing a biochemically/medically relevant intracellular lectin–carbohydrate binding event and that it can be blocked by a small molecule. The same antagonist administered intratracheally attenuated bleomycin‐induced pulmonary fibrosis in a mouse model with a dose/response profile comparing favorably with that of oral administration of the marketed antifibrotic compound pirfenidone. 相似文献
126.
Emilie Bousquet Angéline Poulon-Quintin Monique Puiggali Olivier Devos Marie Touzet 《Corrosion Science》2011,(9):3026-3034
Corrosion sensitivity of a friction stir welded (FSW) AA2024-T3 aluminum alloy has been investigated using both normalized intergranular corrosion test (ASTM-G110) and local electrochemical open circuit potential measurements. In addition, Vickers microhardness and microstructural analysis have been performed.The HAZ close to the TMAZ is the most sensitive to intergranular corrosion because of the presence of continuous lines of S′(S) intergranular precipitates at grain boundaries. Pitting corrosion is due to the intermetallic particles. Their fragmentation produced by stirring effect modifies the pitting corrosion behavior. Microhardness variations depend on the relative volume fraction of GPB zones and S′(S) intragranular precipitates. 相似文献
127.
We explored the production cost of energy crops at abandoned agricultural land and at rest land at a regional and a global level to the year 2050 using four different land-use scenarios. The estimations were based on grid cell data on the productivity of short-rotation crops on the available land over time and assumptions regarding the capital and the labour input required to reach these productivity levels. It was concluded that large amounts of grown biomass at abandoned agricultural land and rest land, 130–270 EJ yr?1 (about 40–70% of the present energy consumption) may be produced at costs below $2 GJ?1 by 2050 (present lower limit of cost of coal). Interesting regions because of their low production cost and significant potentials are the Former USSR, Oceania, Eastern and Western Africa and East Asia. Such low costs presume significant land productivity improvements over time and cost reductions due to learning and capital-labour substitution. An assessment of biomass fuel cost, using the primary biomass energy costs, showed that the future costs of biomass liquid fuels may be in the same order of the present diesel production costs, although this may change in the long term. Biomass-derived electricity costs are at present slightly higher than electricity baseload costs and may directly compete with estimated future production costs of fossil fuel electricity with CO2 sequestration. The present world electricity consumption of around 20 PWh yr?1 may be generated in 2050 at costs below $45 MWh?1 in A1 and B1 and below $55 MWh?1 in A2 and B2. At costs of $60 MWh?1, about 18 (A2) to 53 (A1) PWh yr?1 can be produced. 相似文献
128.
The aim of this study was to investigate how mustard essential oil (EO) affected the cell membrane of Escherichia coli O157:H7 and Salmonella typhi. Intracellular pH and ATP concentration and the release of cell constituents were measured when mustard EO was in contact with E. coli and S. typhi at its minimal inhibitory concentration (MIC) and maximal tolerated concentration (MTC). The treatment with mustard EO affected the membrane integrity of bacteria and induced a decrease of the intracellular ATP concentration. Also, the extracellular ATP concentration increased and a reduction of the intracellular pH was observed in both bacteria. A significantly (P ? 0.05) higher release of cell constituent was observed when both bacteria cells were treated with mustard EO. Electronic microscopy observations showed that the cell membranes of both bacteria were apparently damaged by mustard EO. In conclusion, mustard EO affects the concentration of intracellular component, such as ATP in both bacteria and affects the pH suggesting that cytoplasmic membrane is involved in the antimicrobial action of mustard EO. Mustard EO can be used as an effective antimicrobial agent. We have demonstrated that mustard EO affected the cell membrane integrity, resulting in a loss of cell homeostasis. 相似文献
129.
Khadija Hassan Blondelle Matio Kemkuignou Marco Kirchenwitz Kathrin Wittstein Monique Rascher-Albaghdadi Clara Chepkirui Josphat C. Matasyoh Cony Decock Reinhard W. Kster Theresia E. B. Stradal Marc Stadler 《International journal of molecular sciences》2022,23(21)
Neurotrophins such as nerve growth factor (ngf) and brain-derived neurotrophic factor (bdnf) play important roles in the central nervous system. They are potential therapeutic drugs for the treatment of neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease. In this study, we investigated the neurotrophic properties of triterpenes isolated from fruiting bodies of Laetiporus sulphureus and a mycelial culture of Antrodia sp. MUCL 56049. The structures of the isolated compounds were elucidated based on nuclear magnetic resonance (NMR) spectroscopy in combination with high-resolution electrospray mass spectrometry (HR-ESIMS). The secondary metabolites were tested for neurotrophin (ngf and bdnf) expression levels on human astrocytoma 1321N1 cells. Neurite outgrowth activity using rat pheochromocytoma (PC-12) cells was also determined. Twelve triterpenoids were isolated, of which several potently stimulated the expression of neurotrophic factors, namely, ngf (sulphurenic acid, 15α-dehydroxytrametenolic acid, fomefficinic acid D, and 16α-hydroxyeburicoic acid) and bdnf (sulphurenic acid and 15α-dehydroxytrametenolic acid), respectively. The triterpenes also potentiated ngf-induced neurite outgrowth in PC-12 cells. This is, to the best of our knowledge, the first report on the compound class of lanostanes in direct relation to bdnf and ngf enhancement. These compounds are widespread in medicinal mushrooms; hence, they appear promising as a starting point for the development of drugs and mycopharmaceuticals to combat neurodegenerative diseases. Interestingly, they do not show any pronounced cytotoxicity and may, therefore, be better suited for therapy than many other neurotrophic compounds that were previously reported. 相似文献
130.
Sabah Souliman Eric Beyssac Jean-Michel Cardot Sylvain Denis Monique Alric 《Drug development and industrial pharmacy》2013,39(4):475-483
This work aimed to investigate the biopharmaceutical behavior of hydrophilic matrix tablets of theophylline using different in vitro methods: USP II, USP IV, and a novel in vitro system simulating the gastrointestinal tract in man called the artificial digestive system (ADS). The potentiality of each method was evaluated by establishing in vitro/in vivo correlation. Using USP methods, the drug release was pH-independent and dependent on agitation intensity. Level A IVIVCs could be established using the different in vitro methods but one to one correlation was established only when the ADS method was used. For the prediction of in vivo drug dosage form behavior based on in vitro methods, the ADS showed a high predictability when compared to USP in vitro methods. 相似文献