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111.
112.
Mehta A Magalhães BS Souza DS Vasconcelos EA Silva LP Grossi-de-Sa MF Franco OL da Costa PH Rocha TL 《Current protein & peptide science》2008,9(2):108-116
In recent years, a strong emphasis has been given in deciphering the function of genes unraveled by the completion of several genome sequencing projects. In plants, functional genomics has been massively used in order to search for gene products of agronomic relevance. As far as root-pathogen interactions are concerned, several genes are recognized to provide tolerance/resistance against potential invaders. However, very few proteins have been identified by using current proteomic approaches. One of the major drawbacks for the successful analysis of root proteomes is the inherent characteristics of this tissue, which include low volume content and high concentration of interfering substances such as pigments and phenolic compounds. The proteome analysis of plant-pathogen interactions provides important information about the global proteins expressed in roots in response to biotic stresses. Moreover, several pathogenic proteins superimpose the plant proteome and can be identified and used as targets for the control of viruses, bacteria, fungi and nematode pathogens. The present review focuses on advances in different proteomic strategies dedicated to the challenging analysis of plant defense proteins expressed during bacteria-, fungi- and nematode-root interactions. Recent developments, limitations of the current techniques, and technological perspectives for root proteomics aiming at the identification of resistance-related proteins are discussed. 相似文献
113.
A preconcentration method for manganese determination by sequential injection cloud point extraction with subsequent detection by flame atomic absorption spectrometry (FAAS) has been developed. The enrichment of Mn was performed after a preliminary on-line cloud point extraction and entrapment of manganese-containing surfactant aggregated within a minicolumn packed with cotton. The laboratory-made reagent 4-(5′-bromo-2′-thiazolylazo)orcinol (Br-TAO) and the surfactant Triton X-114 were used for cloud point extraction. The manganese ions were eluted with sulphuric acid solution and directly introduced into the FAAS. Chemical and flow variables affecting the preconcentration were studied. Using a sample volume of 2.80 mL the limit of detection and enrichment factor were calculated to be 0.5 μg L−1 and 14, respectively. The sample frequency is 48 h−1, considering a total run cycle of 75 s. The accuracy of the proposed method has been demonstrated by the analysis of the certified reference biological materials rice flour and tomato leaves. The method has been applied to determination of manganese in food samples. 相似文献
114.
Ursula B. Vasconcelos 《Tetrahedron》2008,64(20):4619-4626
A homologous series of the new N-heterotolans 8a-d were synthesized using two cross-coupling reactions mediated by copper and palladium/copper. The final compounds present the phenyl-pyridyl framework connected by the acetylene group. The evaluation of thermal properties for this series is described. All compounds exhibit the smectic A and X mesophase. For comparison were also synthesized compounds 10, 12, and 14. Their LC properties are reported. 相似文献
115.
Angular distributions and excitation functions of the elastic and inelastic scattering of 3He and α-particles by 122,124Te, 124Sn and 114Cd at incident energies around the Coulomb barrier were measured. The experimental results were analyzed in the framework of the optical model and DWBA taking into account the interference between nuclear and Coulomb excitation. Nuclear and charge deformation parameters were deduced. 相似文献
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A. M. C. Arriaga J. Q. Lima J. N. Vasconcelos M. C. F. de Oliveira M. Andrade‐Neto G. M. P. Santiago D. E. A. Uchoa G. T. Malcher J. Mafezoli R. Braz‐Filho 《Magnetic resonance in chemistry : MRC》2009,47(6):537-540
1H and 13C NMR chemical shifts of praecansone B, pongaflavone and dehydrorotenone isolated from Tephrosia egregia Sandw and obovatin from T. toxicaria Pers. were unambiguously assigned by 1D and 2D NMR experiments including 1H, 1H COSY, gHMQC and gHMBC, allowing the correction of literature assignments.Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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H. C. Vasconcelos 《Journal of Sol-Gel Science and Technology》2010,55(1):126-133
SiO2-TiO2-PO2,5 (STP) and SiO2-TiO2-AlO1,5 (STA) glasses were prepared by sol-gel processing. Their infrared absorption spectra (IR), differential thermal analysis
curves (DTA) and X-ray diffraction patterns (XRD) have been recorded. In the SiO2-TiO2 system, the chemical homogeneity of the sol-gel glass could be evaluated by the relative concentration of Si-O-Ti heterocondensation
comparing to Si-O-Si homocondensation. For the STA system, a gradual decrease of the Si-O-Ti/Si-O-Si band ratio (based on
IR spectra) with the addition of Al2O3 is observed, with the simultaneous formation of Si-O-Al and Ti-O-Al bounds, i.e Al3
+ ions are dissolved in the SiO2-TiO2 glass matrix and do not promote glass-in-glass phase-separation in the composition range of 0–15 mol% AlO1.5. In the STP system, on the other hand, P=O bond IR stretch in the ternary glasses indicates that P=O free PO2O2/2
− tetrahedra are formed, rather than the double bonded POO3/2 tetrahedra that usually occur in binary SiO2-P2O5 glasses. It can be concluded that SiO2-TiO2-P2O5 glass separates into a SiO2-rich phase and a TiO2(P2O5)-rich phase. During heat-treatment in STA system only anatase precipitates, even at T ~ 1,000 °C, while in for STP, anatase (TiO2) or (TiO)2P2O7 (TOP) crystals precipitate at ~600 °C, depending on the P2O5 concentration. The major crystal phase, cristobalite, precipitated at ~1,000 °C and at ~1,200 °C, the P-containing phase
melts. 相似文献