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排序方式: 共有570条查询结果,搜索用时 31 毫秒
31.
Lorenzo Chiaverini Alessandro Pratesi Damiano Cirri Arianna Nardinocchi Iogann Tolbatov Alessandro Marrone Mariagrazia Di Luca Tiziano Marzo Diego La Mendola 《Molecules (Basel, Switzerland)》2022,27(8)
Auranofin (AF, hereafter) is an orally administered chrysotherapeutic agent approved for the treatment of rheumatoid arthritis that is being repurposed for various indications including bacterial infections. Its likely mode of action involves the impairment of the TrxR system through the binding of the pharmacophoric cation [AuPEt3]+. Accordingly, a reliable strategy to expand the medicinal profile of AF is the replacement of the thiosugar moiety with different ligands. Herein, we aimed to prepare the AF analogue bearing the acetylcysteine ligand (AF-AcCys, hereafter) and characterize its anti-staphylococcal activity. Biological studies revealed that AF-AcCys retains an antibacterial effect superimposable with that of AF against Staphylococcus aureus, whereas it is about 20 times less effective against Staphylococcus epidermidis. Bioinorganic studies confirmed that upon incubation with human serum albumin, AF-AcCys, similarly to AF, induced protein metalation through the [AuPEt3]+ fragment. Additionally, AF-AcCys appeared capable of binding the dodecapeptide Ac-SGGDILQSGCUG-NH2, corresponding to the tryptic C-terminal fragment (488–499) of hTrxR. To shed light on the pharmacological differences between AF and AF-AcCys, we carried out a comparative experimental stability study and a theoretical estimation of bond dissociation energies, unveiling the higher strength of the Au–S bond in AF-AcCys. From the results, it emerged that the lower lipophilicity of AF-AcCys with respect to AF could be a key feature for its different antibacterial activity. The differences and similarities between AF and AF-AcCys are discussed, alongside the opportunities and consequences that chemical structure modifications imply. 相似文献
32.
Effect of salinity on petroleum biodegradation 总被引:1,自引:0,他引:1
G. Mille M. Almallah M. Bianchi F. van Wambeke J. C. Bertrand 《Fresenius' Journal of Analytical Chemistry》1991,339(10):788-791
Summary The biodegradation of Ashtart crude oil by a mixed bacterial community (EH1) isolated from a marine sediment was investigated in varying concentration of sodium chloride (0 to 2 mol/l). Each fraction of Ashtart crude oil was biodegraded after a 30 day incubation period for a NaCl concentration equivalent to the one of seawater (0.4 mol/l). Saturates were more readily degraded than aromatics. The amount of oil degraded increased initially with increasing salt concentrations to a maximum level for 0.4 mol/l NaCl concentration. Thereafter the amount of oil degraded decreased with increasing salt concentrations. The polar fraction increased for the 0.4 to 1.4 mol/l NaCl concentration range. Asphaltenes were only slightly degraded (10%) for a NaCl concentration equivalent to the one of seawater (0.4 mol/l). NaCl concentrations seemed to affect the relative biodegradation of pristane and phytane. GC, UV fluorescence and FTIR techniques were used to study the evolution of each fraction of Ashtart crude oil. 相似文献
33.
Patricia W. Stege Germán A. Messina Guillermo Bianchi Roberto A. Olsina 《Journal of fluorescence》2010,20(2):517-523
Enzyme activities can provide indication for quantitative changes in soil organic matter (SOM). It is known that the activities
of most enzymes increase as native SOM content reflecting larger microbial communities and stabilization of enzymes on humic
materials. β-Gucosidase (β-Glu) activities have been frequently used as indicators of changes in quantity and quality of SOM.
In this study we propose a simple and very sensitive method, which has lower limit of detection compared with classic spectrophotometric
method with the aim of determinate the β-Glu activity in soil samples using Fluorescein mono-β-D-glucopyranoside (FMGlc) as
a substrate. The fluorescein released by the enzymatic reaction was quantified by capillary electrophoresis-laser induced
fluorescence (CE-LIF) method. The background electrolyte (BGE) consisted in 40 mM phosphate buffer, pH 6. The LOD and LOQ
for fluorescein were 1.3 10−7 mg mL−1 and 6.4 10−6 mg mL−1, respectively. This work deals with the minimization of the mixture for the enzymatic reaction and with the optimization
conditions of CE separation. To the best of our knowledge, this is the first time that an enzymatic activity was detected
in soil using CE-LIF system. 相似文献
34.
Sfarra Stefano Regi Mauro Tortora Mariagrazia Casieri Cinzia Perilli Stefano Paoletti Domenica 《Journal of Thermal Analysis and Calorimetry》2018,132(2):1367-1387
Journal of Thermal Analysis and Calorimetry - The aim of this work is to evaluate the potentiality of a multi-technique nondestructive approach for characterizing the state of conservation of... 相似文献
35.
Mustapha Raihane Valter Castelvetro Sabrina Bianchi Salima Atlas Bruno Ameduri 《Journal of polymer science. Part A, Polymer chemistry》2010,48(21):4900-4908
A novel copolymer of vinylidene cyanide (VCN) and 2,2,2‐trifluoroethyl methacrylate (MATRIF) was synthesized by bulk free radical process in a 52% yield from an equimolar comonomer feed. The copolymer's composition and microstructure were analyzed by FTIR, 1H‐ and 13C‐NMR spectroscopy, SEC, and elemental analysis. The reactivity ratios calculated from both the Q‐e Alfrey‐Price parameters and the Jenkins' Patterns Scheme indicate a tendency to alternation in the copolymerization, the latter method suggesting that MATRIF homopropagation be slightly favoured (rV = r12 = 0.1, rM = r21 = 0.3). The molar incorporation of VCN in the copolymer was only 42 mol % according to the 9.0 wt % nitrogen content determined by elemental analysis, in good agreement with the value obtained by 1H‐NMR. High‐resolution 1H and 13C‐NMR spectra were used to study the microstructure of the copolymer. As an example, the three well‐resolved carbonyl resonances in the 13C‐NMR spectrum were assigned to the MATRIF‐centered triads VMV, VMM, and MMM, respectively, (V and M stand for VCN and MATRIF, respectively). The presence of VCN dyads (e.g., in VVM and VVV sequences) was shown to be marginal or absent altogether. Thermogravimetric analysis of poly(VCN‐co‐MATRIF) copolymer showed good thermal stability, and its main pyrolytic degradation taking place only above 368 °C. A 4% weight loss at about 222 °C suggested the presence of a few VCN homodyads, possibly inducing thermal depolymerization. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
36.
Ipomoea cairica cell cultures produced a tetrahydrofuran lignan, (+)-pinoresinol, identified by UV, IR, MS and NMR methods, not yet found in the intact plant, and new in the Convolvulaceae family. Pinoresinol was found to have antioxidant and Ca2+ antagonist properties. As it could be requested for its biological activity, we examined the possibility to raise the pinoresinol yield of I. cairica cultures, as well as we continued investigations on lignans' response to optimization. 相似文献
37.
De Vita R Anghinolfi M Burkert VD Dodge GE Minehart R Taiuti M Weller H Adams G Amaryan MJ Anciant E Armstrong DS Asavapibhop B Asryan G Audit G Auger T Avakian H Bagdasaryan H Ball JP Barrow S Battaglieri M Beard K Bektasoglu M Bianchi N Biselli AS Boiarinov S Bonner BE Bosted P Bouchigny S Branford D Brooks WK Bueltmann S Calarco JR Capitani GP Carman DS Carnahan B Cazes A Ciciani L Cole PL Coleman A Connelly J Cords D Corvisiero P Crabb D Crannell H Cummings JP De Sanctis E Degtyarenko PV 《Physical review letters》2002,88(8):082001
The double spin asymmetry in the (-->)e(-->)p --> e(prime)pi(+)n reaction has been measured for the first time in the resonance region for four-momentum transfer Q2 = 0.35-1.5 GeV(2). Data were taken at Jefferson Lab with the CLAS detector using a 2.6 GeV polarized electron beam incident on a polarized solid NH3 target. Comparison with predictions of phenomenological models shows strong sensitivity to resonance contributions. Helicity-1/2 transitions are found to be dominant in the second and third resonance regions. The measured asymmetry is consistent with a faster rise with Q(2) of the helicity asymmetry A1 for the F(15)(1680) resonance than expected from the analysis of the unpolarized data. 相似文献
38.
Joo K Smith LC Burkert VD Minehart R Aznauryan IG Elouadrhiri L Stepanyan S Adams GS Amaryan MJ Anciant E Anghinolfi M Armstrong DS Asavapibhop B Audit G Auger T Avakian H Barrow S Bagdasaryan H Battaglieri M Beard K Bektasoglu M Bertozzi W Bianchi N Biselli AS Boiarinov S Bonner BE Brooks WK Calarco JR Capitani GP Carman DS Carnahan B Cole PL Coleman A Cords D Corvisiero P Crabb D Crannell H Cummings J De Sanctis E De Vita R Degtyarenko PV Demirchyan RA Denizli H Dennis LC Deppman A 《Physical review letters》2002,88(12):122001
Models of baryon structure predict a small quadrupole deformation of the nucleon due to residual tensor forces between quarks or distortions from the pion cloud. Sensitivity to quark versus pion degrees of freedom occurs through the Q2 dependence of the magnetic (M1+), electric (E1+), and scalar (S1+) multipoles in the gamma*p-->Delta(+)-->p pi(0) transition. We report new experimental values for the ratios E(1+)/M(1+) and S(1+)/M(1+) over the range Q2 = 0.4-1.8 GeV2, extracted from precision p(e,e(')p)pi(0) data using a truncated multipole expansion. Results are best described by recent unitary models in which the pion cloud plays a dominant role. 相似文献
39.
40.
Rossi P Mirazita M Ronchetti F De Sanctis E Adams G Ambrozewicz P Anciant E Anghinolfi M Asavapibhop B Audit G Avakian H Bagdasaryan H Ball JP Barrow S Battaglieri M Beard K Bektasoglu M Bellis M Benmouna N Berman BL Bertozzi W Bianchi N Biselli AS Boiarinov S Bonner BE Bouchigny S Bradford R Branford D Briscoe WJ Brooks WK Burkert VD Butuceanu C Calarco JR Carman DS Carnahan B Chen S Cole PL Cords D Corvisiero P Crabb D Crannell H Cummings JP De Vita R Degtyarenko PV Denizli H Dennis L 《Physical review letters》2005,94(1):012301