Home About us Contact
|
Home About us Contact | ||
|
|
||
Thiourea
Kinds of Thiourea Terms modified by Thiourea Selected AbstractsStructural and microhardness studies of pure and thiourea doped glycine phosphite single crystalCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2008R. Ezhil Vizhi Abstract Ferroelectric Glycine Phosphite (GPI) crystal have been grown from aqueous solution employing the slow cooling technique. As the crystal solubility in water depends on temperature, single crystals were grown. Transparent, colourless crystals with habit morphology weighing about 8g were obtained with in a month. The same procedure was used to grow single crystals of 10 wt% of Thiourea doped GPI (TUGPI). Formation of a new crystal was confirmed by Powder X-ray diffraction studies as well as FTIR studies. Crystalline quality were found using rocking curve for both the crystals. Due to the presence of Thiourea in TUGPI, it improves the crystalline perfection and also enhances the growth rate. The variation of hardness on (010) faces of monoclinic GPI and TUGPI crystals, with load were studied.Vickers hardness numbers, Hv were found to decrease with the increase in load. The value of Mayer's index, ,n ' was found to be greater than 1.6 for GPI and TUGPI showing soft-material category. The results are discussed in detail. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis, growth and characterization of single crystals of pure and thiourea doped L-glutamic acid hydrochlorideCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2007R. Sathyalakshmi Abstract L(+)Glutamic acid hydrochloride [HOOC (CH2)2CH(NH2) COOH·HCl], a monoamino dicarboxylic acid salt of L-Glutamic acid was synthesized and the synthesis was confirmed by FTIR analysis. Solubility of the material in water was determined. Pure and Thiourea doped L-Glutamic acid hydrochloride crystals were grown by low temperature solution growth using solvent evaporation technique. XRD, UV-Vis-NIR analyses were carried out for both pure and thiourea doped crystals. The crystals were qualitatively analyzed by EDAX analysis and the presence of thiourea was confirmed. The cell parameters of L-Glutamic acid hydrochloride have been determined as a = 5.151 Å, b = 11.79 Å, c = 13.35 Å by X-ray diffraction analysis and it crystallizes in orthorhombic space group P212121. UV-Vis-NIR spectra analysis showed good optical transmission in the entire visible region for both pure and doped crystals. Micro hardness of both pure and doped crystals has been determined using Vickers micro hardness tester. The SHG efficiencies of both pure and doped crystals were determined using Kurtz powder test and pure L-Glutamic acid hydrochloride crystal was found to possess better efficiency than thiourea doped L-Glutamic acid hydrochloride crystals. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Thiol-reactive dyes for fluorescence labeling of proteomic samplesELECTROPHORESIS, Issue 14 2003Kamala Tyagarajan Abstract Covalent derivatization of proteins with fluorescent dyes prior to separation is increasingly used in proteomic research. This paper examines the properties of several commercially available iodoacetamide and maleimide dyes and discusses the conditions and caveats for their use in labeling of proteomic samples. The iodoacetamide dyes BODIPY TMR cadaverine IA and BODIPY Fl C1 -IA were highly specific for cysteine residues and showed little or no nonspecific labeling even at very high dye:thiol ratios. These dyes also showed minimal effects on pI's of standard proteins. Some iodoacetamide dyes, (5-TMRIA and eosin-5-iodoacetamide) and some maleimide dyes (ThioGlo I and Rhodamine Red C2 maleimide) exhibited nonspecific labeling at high dye:thiol ratios. Labeling by both iodoacetamide and maleimide dyes was inhibited by tris(2-carboxyethyl)phosphine (TCEP); interactions between TCEP and dye were also observed. Thiourea, an important component of sample solubilization cocktails, inhibited labeling of proteins with iodoacetamide dyes but not with maleimide dyes. Maleimide dyes may serve as an alternative for labeling proteins where it is essential to have thiourea in the solubilization buffer. Covalent derivatization by BODIPY TMR cadaverine IA, BODIPY Fl C1 -IA or Rhodamine Red C2 maleimide was also demonstrated to be compatible with in-gel digestion and peptide mass fingerprinting by matrix assisted laser desorption/ionization-mass spectrometry and allowed successful protein identification. [source] The Reaction of (Bipyridyl)palladium(II) Complexes with Thiourea , Influence of DNA and Other Polyanions on the Rate of ReactionEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2005Matteo Cusumano Abstract [Pd(bipy)(py)2](PF6)2 reacts stepwise with excess thiourea to give [Pd(tu)4](PF6)2. The kinetics of the second step, which refers to the replacement of bipyridyl in [Pd(bipy)(tu)2](PF6)2, have been studied in water and in the presence of calf thymus DNA, sodium polyriboadenylate, sodium polyvinylsulfonate or sodium polymetaphosphate at 25 °C and pH = 7 and a fixed sodium chloride concentration. The reaction follows a first order course and a plot of kobs against [thiourea]2 affords a straight line with a small intercept. DNA inhibits the process without altering the rate law. The kobs values decrease systematically on increasing the DNA concentration eventually tending to a limiting value. The values are larger at higher ionic strengths and the other polyanions show similar behaviour. The influence of DNA on the kinetics can be related to steric inhibition caused by noncovalent binding with the complex. Upon interaction with DNA, [Pd(bipy)(tu)2]2+ gives rise to immediate spectroscopic changes in the UV/Vis region as well as induced circular dichroism suggesting that the complex, like similar platinum(II) and palladium(II) species of bipyridyl, intercalates with the double helix. Such a type of interaction hampers the attack of the nucleophile at the metal centre inhibiting the reaction. The decrease in the rate of ligand substitution upon decreasing salt concentration but at a given DNA concentration is due to the influence of ionic strength on the complex,DNA interaction. The reactivity inhibition by single-stranded poly(A), polyvinylsulfonate or polymetaphosphate can be accounted for in terms of self-aggregation of the complex induced by the polyanion. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Kinetic and mechanistic investigation into the influence of chelate substituents on the substitution reactions of platinum(II) terpyridine complexesINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 12 2008Deogratius Jaganyi The substitution kinetics of the complexes [Pt{4,-(o -CH3 -Ph)-terpy} Cl]SbF6 (CH3PhPtCl(Sb)), [Pt{4,-(o -CH3 -Ph)-terpy}Cl]CF3SO3 (CH3PhPtCl(CF)), [Pt(4,-Ph-terpy)Cl]SbF6 (PhPtCl), [Pt(terpy)Cl]Cl·2H2O (PtCl), [Pt{4,-(o -Cl-Ph)-terpy}Cl]SbF6 (ClPhPtCl), and [Pt{4,-(o -CF3 -Ph)-terpy}Cl]SbF6 (CF3PhPtCl), where terpy is 2,2,:6,,2,-terpyridine, with the nucleophiles thiourea (TU), N,N,-dimethylthiourea (DMTU), and N,N,N,,N,-tetramethylthiourea (TMTU) were investigated in methanol as a solvent. The substitution reactions of the chloride displacement from the metal complexes by the nucleophiles were investigated as a function of nucleophile concentration and temperature under pseudo-first-order conditions using the stopped-flow technique. The reactions followed the simple rate law kobs = k2[Nu]. The results indicate that the introduction of substituents in the ortho position of the phenyl group on the ancillary ring of the terpy unit does influence the extent of ,-backbonding in the terpy ring. This controls the electrophilicity of the platinum center, which in turn controls the lability of the chloro-leaving group. The strength of the electron-donating or -withdrawing ability of the substituents correlates with the reactivity of the complexes. Electron-donating substituents decrease the rate of substitution, whereas electron-withdrawing substituents increase the rate of substitution. This was supported by DFT calculations at the B3LYP/LACVP+** level of theory, which showed that most of the electron density of the HOMO is concentrated on the phenyl ligand rather than on the metal center in the case of the strongest electron-withdrawing substituent in CF3PhPtCl. The opposite was found to be true with the strongest electron-donating substituent in CH3PhPtCl. Thiourea was found to be the best nucleophile with N,N,N,,N,-tetramethylthiourea being the weakest due to steric effects. The temperature dependence studies support an associative mode of activation. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 808,818, 2008 [source] Highly Enantioselective Michael Addition Reactions of 3-Substituted Benzofuran-2(3H)-ones to Chalcones Catalyzed by a Chiral Alkyl-Substituted ThioureaADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2010Xin Li Abstract A highly enantioselective Michael addition of 3-substituted benzofuran-2(3H)-ones to chalcones catalyzed by a chiral bifunctional thiourea was developed. Several chiral 3,3,-substituted benzofuran-2(3H)-ones derivatives, bearing adjacent quaternary-tertiary stereocenters, were efficiently synthesized with excellent enantioselectivities. [source] Organocatalytic Asymmetric Michael Addition of Pyrazolin-5-ones to Nitroolefins with Bifunctional Thiourea: Stereocontrolled Construction of Contiguous Quaternary and Tertiary StereocentersADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2010Yu-Hua Liao Abstract The first organocatalytic diastereo- and enantioselective Michael addition reaction of 4-substituted-pyrazolin-5-ones to nitroolefins has been developed with a chiral bifunctional thiourea as organocatalyst. A wide variety of desired multi-substituted pyrazolin-5-one derivatives with contiguous quaternary and tertiary stereocenters are smoothly obtained in very good yields (up to 98%) with excellent enantioselectivities (up to>99% ee) and acceptable diastereoselectivities (up to 80:20). This experimentally simple process facilitates the access to various enantioenriched, multiply substituted pyrazolin-5-one derivatives, potential biologically active molecules, starting from readily available starting materials. [source] One-Pot Thioetherification of Aryl Halides Using Thiourea and Alkyl Bromides Catalyzed by Copper(I) Iodide Free from Foul-Smelling Thiols in Wet Polyethylene Glycol (PEG 200)ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2010Habib Firouzabadi Abstract In this article, we have developed a new protocol for the thioarylation of structurally diverse alkyl bromides such as benzyl, cinnamyl, n -octyl, cyclohexyl, cyclopentyl, and tert -butyl bromides with aryl iodides, bromides and an activated chloride using thiourea catalyzed by copper(I) iodide in wet polyethylene glycol (PEG 200) as an eco-friendly medium in the presence of potassium carbonate at 80 and 100,°C under an inert atmosphere. The process is free from foul-smelling thiols which makes this method more practical for the thioetherification of aryl halides. Another important feature of this method is the variety of alkyl bromides which are commercially available for the in situ generation of thiolate ions with respect to the existing protocols in which the less commercially available thiols are directly used for the preparation of arylthio ethers. [source] Catalase inhibition alters suberization and wound healing in potato (Solanum tuberosum) tubersPHYSIOLOGIA PLANTARUM, Issue 3 2007Mohammed Bajji In response to wounding, potato (Solanum tuberosum L.) tubers generate hydrogen peroxide (H2O2) in association with suberization, a critical phase of the wound-healing process. In the present study, the effect of aminotriazole (AT), a catalase (CAT, EC 1.11.1.6) inhibitor, on cut tubers was investigated using fresh weight (FW) loss and pathogen attack symptoms as indicators of wound-healing efficiency. Seven days after treatment, AT-treated tuber halves lost more FW and developed infection signs compared with the controls. Thiourea, another CAT inhibitor, as well as exogenous H2O2 treatments induced the same effects as AT suggesting that the alteration of the wound healing may be caused by CAT inhibition and the resulting accumulation of H2O2. Using transgenic tubers, FW losses 1 week after wounding were either higher (CAT repression) or lower (CAT overexpression) than those of the wild-type. When tuber halves were allowed to wound heal for different periods before treatment, AT had no effect on the progress of their wound healing if wound-healed for at least 3 days. This implies that AT may affect early wound-healing-related events, especially those occurring before or during suberization. A time-course analysis of the effects of AT treatment on wounded tuber tissues revealed that AT prevented the deposition of the polyphenolic domain of suberin in association with CAT inhibition and H2O2 accumulation. These data are important in identifying factors that may be required to regulate suberization and contribute to a better understanding of this critical process to hasten its rate and limit wound-related losses in stored potato tubers. [source] ChemInform Abstract: Direct Imidation of Construct 1H-Benzo[d]imidazole Through Pd(II)-Catalyzed C,H Activation Promoted by Thiourea.CHEMINFORM, Issue 50 2009Qing Xiao Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Facile Generation of C,S Bonds via One-Pot, Odorless and Efficient Thia-Michael Addition Reactions Using Alkyl, Aryl or Allyl Halides, Thiourea and Electron-Deficient Alkenes in Wet Polyethylene Glycol (PEG 200) under Mild Reaction Conditions.CHEMINFORM, Issue 44 2009Habib Firouzabadi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: NCS with Thiourea as Highly Efficient Catalysts for Acetalization of Aldehydes.CHEMINFORM, Issue 43 2009Y. Mei Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Reaction of Divinyl Selenide with Thiourea.CHEMINFORM, Issue 49 2008S. V. Amosova Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Thiourea to Dithiazolopyrimidines: Highly Regio- and Stereoselective Synthetic Routes via Mercaptoacetylative Cyclization.CHEMINFORM, Issue 20 2008Lal Dhar S. Yadav Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Spiro-Heterocyclization of Pyrrolobenzoxazinetriones (I) Effected by Thiourea.CHEMINFORM, Issue 12 2008A. V. Babenysheva Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Oxazoline,Thiourea as a Bifunctional Organocatalyst: Enantioselective aza-Henry Reactions.CHEMINFORM, Issue 3 2008Yu-wei Chang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Reactions of 1,2-Dinitroethenes with Thiourea and N,N,-Diphenylthiourea.CHEMINFORM, Issue 20 2004T. Yu. Abstract For Abstract see ChemInform Abstract in Full Text. [source] New Substituted Derivatives of Thiourea.CHEMINFORM, Issue 49 2003IR Spectra., Synthesis 1H-NMR No abstract is available for this article. [source] Transformation of a zinc inclusion complex to wurtzite ZnS microflowers under solvothermal conditionsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2010Liwei Mi Abstract Wurtzite zinc sulfide (ZnS) microflowers were synthesized successfully by a convenient solvothermal route in ethylene glycol (EG) and ethylenediamine (EN) using thiourea and zinc inclusion complex as starting materials. The inclusion complex {[Zn(bipy)2(H2O)2](4-Cl-3-NH2 -C6H3SO3)2(bipy) (H2O)2}n was achieved by the reaction of zinc oxide (ZnO) and 4-Cl-3-NH2 -C6H3SO3 with the bridging ligand bipy under moderate conditions, in which bipy is 4,4,-bipyridine and 4-Cl-3-NH2C6H3SO3NH is 4-Chloro-3-aminobenzene sulfonic acid. The phase purity of bulk products was confirmed by powder X-ray diffraction and element analysis. The factors that might affect the purity of the ZnS product during the synthesis were discussed in detail. It was found that the products were significantly affected by the mixed solvents and the starting materials. X-ray single crystal diffraction, scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD) were used to characterize the products. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preparation of shuttle-like Sb2S3 nanorod-bundles via a solvothermal approach under alkaline conditionCRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2010Ling Zhang Abstract Uniform shuttle-like Sb2S3 nanorod-bundles were synthesized via a polyvinylpyrrolidone (PVP) assisted solvothermal approach under alkaline condition, using antimony chloride (SbCl3) and thiourea (CH4N2S, Tu) as the starting materials in ethanol. The phase structure, composition and morphology of the product were characterized by means of X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). XRD and EDS results confirm that the synthesized Sb2S3 nanorod-bundles have an orthorhombic structure and an atomic ratio of 3:2 for S:Sb. TEM and HRTEM results show that the shuttle-like Sb2S3 bundles are composed of nanorods with a size distribution of 20-40 nm and growing along c-axis. Furthermore, experiments under different reaction conditions were carried out and the mechanism for the growth of nanorod-bundles was discussed (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Structural and microhardness studies of pure and thiourea doped glycine phosphite single crystalCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2008R. Ezhil Vizhi Abstract Ferroelectric Glycine Phosphite (GPI) crystal have been grown from aqueous solution employing the slow cooling technique. As the crystal solubility in water depends on temperature, single crystals were grown. Transparent, colourless crystals with habit morphology weighing about 8g were obtained with in a month. The same procedure was used to grow single crystals of 10 wt% of Thiourea doped GPI (TUGPI). Formation of a new crystal was confirmed by Powder X-ray diffraction studies as well as FTIR studies. Crystalline quality were found using rocking curve for both the crystals. Due to the presence of Thiourea in TUGPI, it improves the crystalline perfection and also enhances the growth rate. The variation of hardness on (010) faces of monoclinic GPI and TUGPI crystals, with load were studied.Vickers hardness numbers, Hv were found to decrease with the increase in load. The value of Mayer's index, ,n ' was found to be greater than 1.6 for GPI and TUGPI showing soft-material category. The results are discussed in detail. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis, growth and characterization of single crystals of pure and thiourea doped L-glutamic acid hydrochlorideCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2007R. Sathyalakshmi Abstract L(+)Glutamic acid hydrochloride [HOOC (CH2)2CH(NH2) COOH·HCl], a monoamino dicarboxylic acid salt of L-Glutamic acid was synthesized and the synthesis was confirmed by FTIR analysis. Solubility of the material in water was determined. Pure and Thiourea doped L-Glutamic acid hydrochloride crystals were grown by low temperature solution growth using solvent evaporation technique. XRD, UV-Vis-NIR analyses were carried out for both pure and thiourea doped crystals. The crystals were qualitatively analyzed by EDAX analysis and the presence of thiourea was confirmed. The cell parameters of L-Glutamic acid hydrochloride have been determined as a = 5.151 Å, b = 11.79 Å, c = 13.35 Å by X-ray diffraction analysis and it crystallizes in orthorhombic space group P212121. UV-Vis-NIR spectra analysis showed good optical transmission in the entire visible region for both pure and doped crystals. Micro hardness of both pure and doped crystals has been determined using Vickers micro hardness tester. The SHG efficiencies of both pure and doped crystals were determined using Kurtz powder test and pure L-Glutamic acid hydrochloride crystal was found to possess better efficiency than thiourea doped L-Glutamic acid hydrochloride crystals. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystal structure of N-[(1Z)-1-(3-methyl-3-phenylcyclobutyl)-2-thiomorpholin-4-ylethylidene] thioureaCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2005U. Sar Abstract The crystal structure of N-[(1Z)-1-(3-methyl-3-phenylcyclobutyl)-2-thiomorpholin-4-ylethylidene] thiourea (C18H26N4S2) has been determined by X-ray crystallographic techniques. The compound crystallizes in the orthorhombic space group Pbca, with unit cell parameters: a = 15.692(3), b = 20.803(8), c = 11.979(6)Å, Z = 8, V = 3911(7)Å3. The crystal structure was solved by direct methods and refined by full-matrix least squares to a final R-value of 0.084 for 1447 observed reflections [I > 2, ( I ) ]. In the thiosemicarbazide moiety, the S = C bond length is 1.656(6), N-C-N angle is 115.6(5)°. The crystal structure is stabilized by the intermolecular N-H...S hydrogen bonds. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] PbS crystals with clover-like structure: Preparation, characterization, optical properties and influencing factorsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3 2004Yonghong Ni Abstract A new and simple route to synthesize Lead sulfide (PbS) crystals with the clover-like structure was described in the current paper. PbS was prepared in a simple aqueous solution employing (CH3COO)2Pb and thiourea as the initial materials under 130 W microwave irradiation. No any surfactant or template including organic polyamines with N-chelation property was needed. The phase and composition of the product were identified by X-ray powder diffraction (XRD) and X-ray photoelectron spectra (XPS). TEM observation showed that the product with the six-petal flower-shaped structures was obtained, but SEM observation confirmed the clover-like structure of the product; and the six-petal flowers were formed via the overlap of two clovers revolved 60° around the center of the flower. Some factors affected the shape of the final product were studied and the optical properties of PbS crystals with the clover-like structure were measured. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Sugarcane proteomics: Establishment of a protein extraction method for 2-DE in stalk tissues and initiation of sugarcane proteome reference mapELECTROPHORESIS, Issue 12 2010Ramesh Sundar Amalraj Abstract Sugarcane is an important commercial crop cultivated for its stalks and sugar is a prized commodity essential in human nutrition. Proteomics of sugarcane is in its infancy, especially when dealing with the stalk tissues, where there is no study to date. A systematic proteome analysis of stalk tissue yet remains to be investigated in sugarcane, wherein the stalk tissue is well known for its rigidity, fibrous nature, and the presence of oxidative enzymes, phenolic compounds and extreme levels of carbohydrates, thus making the protein extraction complicated. Here, we evaluated five different protein extraction methods in sugarcane stalk tissues. These methods are as follows: direct extraction using lysis buffer (LB), TCA/acetone precipitation followed by solubilization in LB, LB containing thiourea (LBT), and LBT containing tris, and phenol extraction. Both quantitative and qualitative protein analyses were performed for each method. 2-DE analysis of extracted total proteins revealed distinct differences in protein patterns among the methods, which might be due to their physicochemical limitations. Based on the 2-D gel protein profiles, TCA/acetone precipitation-LBT and phenol extraction methods showed good results. The phenol method showed a shift in pI values of proteins on 2-D gel, which was mostly overcome by the use of 2-D cleanup kit after protein extraction. Among all the methods tested, 2-D cleanup-phenol method was found to be the most suitable for producing high number of good-quality spots and reproducibility. In total, 30 and 12 protein spots commonly present in LB, LBT and phenol methods, and LBT method were selected and subjected to eLD -IT-TOF-MS/MS and nESI-LC-MS/MS analyses, respectively, and a reference map has been established for sugarcane stalk tissue proteome. A total of 36 nonredundant proteins were identified. This is a very first basic study on sugarcane stalk proteome analysis and will promote the unexplored areas of sugarcane proteome research. [source] Open-tubular capillary electrochromatography using a capillary coated with octadecylamine-capped gold nanoparticlesELECTROPHORESIS, Issue 4 2008Qishu Qu Dr. Abstract Octadecylamine-capped gold nanoparticles (ODA-Au-NPs) were prepared and characterized by using UV,Vis adsorption spectrum, transmission electron chromatography (TEM), SEM, and FT-IR. A simple but robust hydrophobic coating was easily developed by flushing a capillary with a solution of ODA-Au-NPs, because the positive charges were carried by the nanoparticles which strongly adsorb to the negatively charged inner surface of a fused-silica capillary via electrostatic and hydrophobic interactions. The chromatographic characteristics of the coated capillary was investigated by varying the experimental parameters such as buffer pH, buffer concentration, and percentage of organic modifier in the mobile phase. The results show that (i) resolution between thiourea and naphthalene is almost the same when comparing the electrochromatograms obtained using pH,7 buffer as mobile phase after and before the capillary column was operated using pH,11 and 3 mobile phase; (ii) no significant changes in retention time and deterioration in peak efficiency were found after 60,runs of test aromatic mixtures; and (iii) column efficiency up to 189,000 theoretical plates/meter for testosterone was obtained. All of the results indicated that the coating could act as a stable stationary phase for open tubular CEC as well as for bioanalysis. [source] Thiol-reactive dyes for fluorescence labeling of proteomic samplesELECTROPHORESIS, Issue 14 2003Kamala Tyagarajan Abstract Covalent derivatization of proteins with fluorescent dyes prior to separation is increasingly used in proteomic research. This paper examines the properties of several commercially available iodoacetamide and maleimide dyes and discusses the conditions and caveats for their use in labeling of proteomic samples. The iodoacetamide dyes BODIPY TMR cadaverine IA and BODIPY Fl C1 -IA were highly specific for cysteine residues and showed little or no nonspecific labeling even at very high dye:thiol ratios. These dyes also showed minimal effects on pI's of standard proteins. Some iodoacetamide dyes, (5-TMRIA and eosin-5-iodoacetamide) and some maleimide dyes (ThioGlo I and Rhodamine Red C2 maleimide) exhibited nonspecific labeling at high dye:thiol ratios. Labeling by both iodoacetamide and maleimide dyes was inhibited by tris(2-carboxyethyl)phosphine (TCEP); interactions between TCEP and dye were also observed. Thiourea, an important component of sample solubilization cocktails, inhibited labeling of proteins with iodoacetamide dyes but not with maleimide dyes. Maleimide dyes may serve as an alternative for labeling proteins where it is essential to have thiourea in the solubilization buffer. Covalent derivatization by BODIPY TMR cadaverine IA, BODIPY Fl C1 -IA or Rhodamine Red C2 maleimide was also demonstrated to be compatible with in-gel digestion and peptide mass fingerprinting by matrix assisted laser desorption/ionization-mass spectrometry and allowed successful protein identification. [source] Synthesis, Characterisation and Optical Properties of Silica Nanoparticles Coated with Anthracene Fluorophore and Thiourea Hydrogen-Bonding SubunitsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 36 2008Pilar Calero Abstract Bifunctionalised hybrid silica nanoparticles have been synthesised and characterised, and their optical emission properties in the presence of certain anions in acetonitrile solutions have been studied. The alkoxysilane derivatives N -butyl- N, -[3-(trimethoxysilyl)propyl]thiourea (1), N -phenyl- N, -[3-(trimethoxysilyl)propyl]thiourea (2) and 3-[(anthracen-10-yl)methylthio]propyltriethoxysilane (3) were prepared and used to functionalise uncoated LUDOX silica nanoparticles with a mean diameter of 18,±,2 nm. The functionalisation of the nanoparticle surfaces was carried out by two different approaches. The first approach relies on the consecutive grafting of the two subunits. In this protocol, the nanoparticles were first functionalised with anthracene derivative 3 (solid NA), and then treated with the corresponding binding sites 1 or 2 to result in the NA-Pt3 and NA-Bt3 solids. The second approach deals with the simultaneous grafting of 1 or 2 and the signalling subunit 3 in different ratios. This method was used for the preparation of the NA1Pt1, NA1Bt1, NA1Pt3 and NA1Bt3 nanoparticles. The bifunctionalised silica nanoparticles were characterised by using standard techniques. Acetonitrile suspensions of NA nanoparticles (5 mg in 20 mL) showed anthracene bands centred at ca. 350, 370 and 390 nm. Upon excitation at 365 nm, a typical emission band with fine structure in the 390,450 nm range was observed. Similar absorption and emission spectra were found for the bifunctionalised nanoparticles. The work is completed with a prospective study of the fluorescence of the prepared nanoparticles in the presence of organic (acetate, benzoate) and inorganic (F,, Cl,, Br,, CN,, HSO4, and H2PO4,) anions. The apparent binding constants (adsorption constants) for the interaction of NA-Pt3 with anions in acetonitrile were determined by performing a Langmuir-type analysis of fluorescence titration data.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Quantum Chemical Analysis of the Enantiomerisation Mechanism of Complexes of the Type [MII(XU)4]F+ (M = Pt, Pd, Ni; X = S, Se, Te;U = urea)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 20 2006Ralph Puchta Abstract The enantiomerisation pathway for {[Pt(thiourea)4]}F+ [a model for the C4 -symmetric [Pt(SU)4]SiF6 (SU = thiourea) complex] and derivatives is explored by density functional theory (B3LYP/LANL2DZp) und the activation barrier for the one-step process from C4 to C4, via a C4 transition state is computed. The substitution of Pt2+ by Pd2+ and Ni2+ and the exchange of selenourea and tellurourea increase the barrier. ({[Pt(thiourea)4]}F+: 4.2 kcal/mol, {[Pd(thiourea)4]}F+: 4.5 kcal/mol, {[Ni(thiourea)4]}F+: 7.6 kcal/mol, {[Pt(selenourea)4]}F+: 5.3 kcal/mol, {[Pt(tellurourea)4]}F+: 8.8 kcal/mol). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] The Reaction of (Bipyridyl)palladium(II) Complexes with Thiourea , Influence of DNA and Other Polyanions on the Rate of ReactionEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2005Matteo Cusumano Abstract [Pd(bipy)(py)2](PF6)2 reacts stepwise with excess thiourea to give [Pd(tu)4](PF6)2. The kinetics of the second step, which refers to the replacement of bipyridyl in [Pd(bipy)(tu)2](PF6)2, have been studied in water and in the presence of calf thymus DNA, sodium polyriboadenylate, sodium polyvinylsulfonate or sodium polymetaphosphate at 25 °C and pH = 7 and a fixed sodium chloride concentration. The reaction follows a first order course and a plot of kobs against [thiourea]2 affords a straight line with a small intercept. DNA inhibits the process without altering the rate law. The kobs values decrease systematically on increasing the DNA concentration eventually tending to a limiting value. The values are larger at higher ionic strengths and the other polyanions show similar behaviour. The influence of DNA on the kinetics can be related to steric inhibition caused by noncovalent binding with the complex. Upon interaction with DNA, [Pd(bipy)(tu)2]2+ gives rise to immediate spectroscopic changes in the UV/Vis region as well as induced circular dichroism suggesting that the complex, like similar platinum(II) and palladium(II) species of bipyridyl, intercalates with the double helix. Such a type of interaction hampers the attack of the nucleophile at the metal centre inhibiting the reaction. The decrease in the rate of ligand substitution upon decreasing salt concentration but at a given DNA concentration is due to the influence of ionic strength on the complex,DNA interaction. The reactivity inhibition by single-stranded poly(A), polyvinylsulfonate or polymetaphosphate can be accounted for in terms of self-aggregation of the complex induced by the polyanion. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] | ||||||||||||||||||||||||||||||||||