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61.
S-Adenosyl-L-homocysteine hydrolase (SAHh) inhibitors have long been used as broad-range antivirals and have been recently evaluated as an experimental therapy of filovirus infections. In response to the need for a rapid laboratory testing method that could assess antiviral potency in vivo, our group developed a capillary electrophoresis (CE) method for the determination of the S-adenosyl-L-homocysteine (SAH) to S-adenosyl-L-methionine (SAM) ratio. After chloroacetaldehyde derivatization, SAH and SAM were detected using laser-induced fluorescence detection with a HeCd laser. Separation and quantitation of both SAH and SAM in human plasma were achieved in less than 1 min. The proposed method is rapid and reliable, and could be easily applied to routine monitoring of clinical and preclinical trials subjects. 相似文献
62.
Francesca Benedini Giorgio Bertolini Francesco Ferrario Angelo Motti Alberto Sala Flavio Somenzi 《Journal of heterocyclic chemistry》1995,32(1):103-107
The preparation and the physico-chemical characterization of 2H-pyrido[2,3-e]-1,3-oxazine-2,4(3H)-diones, 2H-pyrido[4,3-e]-1,3-oxazine-2,4(3H)-diones, 2H-pyrido[4,3-e]-1,3-oxazin-4(3H)-ones, 2H-thieno[2,3-e]-1,3-oxazin-4(3H)-ones and 2H-thieno[3,4-e]-1,3-oxazine-2,4(3H)-diones are reported. 相似文献
63.
Lorenzo MalavasiPaolo Ghigna Gaetano ChiodelliGiorgio Maggi Giorgio Flor 《Journal of solid state chemistry》2002,166(1):171-176
The synthesis and structural properties of Mg1−xMn2+xO4, for 0≤x≤1 are described. Complete miscibility in the solid state exists for this system. For the material with the correct stoichiometry, i.e. MgMn2O4, the effect of temperature on the cation distribution was investigated= above 600°C the inversion degree (m) starts increasing. The electrical conductivity shows a small dependence on P(O2) which is consistent with the small oxygen non-stoichiometry determined by means of thermogravimetry. The main contribution to the transport properties arises from the inversion equilibrium. Two distinct conductivity regimes, below and above the inversion threshold, can be assumed to explain the electrical conductivity and thermoelectric power results. 相似文献
64.
Alberto Ballistreri Domenico Garozzo Mario Giuffrida Pietro Maravigna Giorgio Montaudo 《Journal of polymer science. Part A, Polymer chemistry》1986,24(2):331-346
The thermal fragmentation processes in poly-Schiff bases have been investigated by direct pyrolysis–mass spectrometry. The mass spectral data show that the thermal fragmentation occurring in the polymers under investigation is characterized by hydrogen transfer reactions. In the case of a totally aromatic poly-Schiff base (polymer I ), the thermal fragmentation process involves hydrogen transfer irom the methyne group with formation of fragments bearing nitrile and/or phenyl end groups. In the case of aromatic-aliphatic poly-Schiff bases (polymers II–IV ), the hydrogen transfer process occurs from the aliphatic methylene groups. The latter process involves a lower energy and therefore occurs at lower temperatures with respect to the totally aromatic polymer I , with formation of thermal fragments bearing olefin and/or imine end groups. Beside these fragments, several thermal fragmentation compounds are also evolved by multiple hydrogen transfer reactions. 相似文献
65.
An enantioselective addition of titanium phenylacetylide to ketones, promoted by BINOL, is described; this new enantioselective protocol gives high enantiomeric excess (up to 90% ee) with aromatic ketones using a simple procedure without pyrophoric or expensive reagents. 相似文献
66.
Bacchi Alessia Pelizzi Giancarlo Minardi Giovannina Pistuddi Angelo M. Solinas Costantino Chelucci Giorgio 《Transition Metal Chemistry》2002,27(3):274-278
Metal complexes of general formula M(L)X2 and M(L)X3 [L = (4S,5S)-2,2-dimethyl-4,5-bis{6-[(4,5-dihydro-4-(S)-(1-methylethyl)oxazol-2-yl)pyridin-2-yl]}-1,3-dioxolane] were obtained by reacting, respectively, CoII, CuII, NiII, and ZnII nitrate salts and the RhIII chloride salt, with a chiral C2-symmetric bis(oxazolinylpyridinyl)dioxolane (L) ligand, in MeOH/CHCl3 solution. A single crystal X-ray analysis was carried out on [Ni(L)(OH2)2](NO3)2 · 2H2O and the molecular structure of L was also determined. In the free ligand the two symmetric arms are essentially planar and oriented nearly perpendicular to the dioxolane average plane. In the Ni complex one seven-membered and two five-membered chelation rings are formed. The metal atom also lies on the C2 axis, and two symmetry-related water molecules complete the octahedral coordination environment. Both compounds crystallize in chiral space groups; the ligand crystallizes in orthorhombic system, space group C 2 2 21, Z = 4; the nickel complex crystallizes in tetragonal system, space group P 43 21 2, Z = 4. 相似文献
67.
Molins Elies Roig Anna Miravitlles Carlos Moreno-Mañas Marcial Vallribera Adelina Gálvez Nicanor Serra Neus 《Structural chemistry》1998,9(3):203-208
The crystal and molecular structure of (BzlMe3N)
2
+
[Fe2OCl6]2- has been determined. The asymmetric unit contains two benzyltrimethylammonium cations and two half -oxo-bis(trichloro-iron(III)) anions. The bridging -oxygen atoms of these anions are located over crystallographic symmetry elements. Therefore, the two anions resulting from the symmetry operations correspond to two different conformers presenting angular and linear dispositions of the Fe-O-Fe bond angle. Mössbauer spectrum consists of two asymmetric lines that are adequately simulated by two equally populated quadrupole doublets associated with the two iron sites. 相似文献
68.
Dalla Serra M Coraiola M Viero G Comai M Potrich C Ferreras M Baba-Moussa L Colin DA Menestrina G Bhakdi S Prévost G 《Journal of chemical information and modeling》2005,45(6):1539-1545
Staphylococcal gamma-hemolysins are bicomponent toxins forming a protein family with leucocidins and alpha-toxin. Two active toxins (AB and CB) can be formed combining one of the class-S components, HlgA or HlgC, with the class-F component HlgB. These two gamma-hemolysins form pores with marked similarities to alpha-toxin in terms of conductance, nonlinearity of the current-voltage curve, and channel stability in the open state. AB and CB pores, however, are cation-selective, whereas alpha-toxin is anion-selective. gamma-Hemolysins' pores are hetero-oligomers formed by three or four copies of each component (indicated as 3A3B and 3C3B or 4A4B and 4C4B). Point mutants located on a beta-strand of the class-S component that forms part of the protomer-protomer contact region can prevent oligomer assembly. Interestingly, these mutants inhibit growth of pores formed not only by their natural components but also by nonstandard components. This lead to the hypothesis that mixed ABC pores could also be formed. By studying the conductance of pores, assembled in the presence of all three components (in different ratios), it was observed that the magnitudes expected for mixed pores were, indeed, present. We conclude that the gamma-hemolysin/leucocidin bicomponent toxin family may form a larger than expected number of active toxins by cross-combining various S and F components. 相似文献
69.
Pier Giorgio Righetti Barbara Barzaghi Edoardo Sarubbi Adolfo Soffientini Giovanni Cassani 《Journal of chromatography. A》1989,470(2):337-350
When analysing homogeneous preparations of recombinant pro-urokinase and urinary urokinase by isoelectric focusing (IEF) in immobilized pH gradients, an extreme charge heterogeneity was detected (at least ten major and ten minor bands in the pH range 7–10). This extensive polydispersity was not caused by different degrees of glycosylation, or by IEF artefacts, such as binding to carrier ampholytes or carbamylation by urea. A great part of this heterogeneity could be traced back to the existence of a multitude of protein molecules containing Cys residues at different oxidation levels (-SH, -S-S-, even cysteic acid). Owing to the very large number of Cys residues in pro-urokinase (24 out of a total of 411 amino acids) and to the relatively high pI of its native forms (pI 9.5–9.8; the native form is believed to contain all Cys residues as -S-S- bridges), the presence of SH or cysteic acid residues would increase the negative surface charge, as even SH groups would be extensively ionized. In pro-urokinase, part of the heterogeneity was also due to spontaneous degradation to urokinase and possibly also to cleavage into lower-molecular-mass fragments. When all these causes of heterogeneity were removed, the pI spectrum was reduced to only four, about equally intense, bands. The cause of this residual heterogeneity is unknown. 相似文献
70.
Emilio Toja Giorgio Tarzia Pietro Ferrari Giorgio Tuan 《Journal of heterocyclic chemistry》1986,23(5):1555-1560
A series of 4,7-dihydro-4-oxo-1H-pyrrolo[2,3-b]pyridine-5-carboxylic acids was synthesized from ethyl 5-methyl(or 5H)-2-aminopyrrole-3-carboxylate. The starting pyrroles were obtained by reaction of carbethoxyacetamidine with bromoacetone or chloroacetaldehyde. One compound ( 10 ) showed antibacterial activity in vitro. 相似文献