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201.
Cell-based screening systems for pharmaceuticals are desired over molecular biosensing systems because of the information
they provide on toxicity and bioavailability. However, the majority of sensing systems developed are molecular biosensing
type screening systems and cannot be easily adapted to cell-based screening. In this study, we demonstrate that protein-based
molecular sensing systems that employ a fluorescent protein as a signal transducer are amenable to cell-based sensing by expressing
the protein molecular sensing system in the cell and employing these cells for screening of desired molecules. To achieve
this, we expressed a molecular sensing system based on the fusion protein of calmodulin (CaM) and enhanced green fluorescent
protein (EGFP) in bacterial cells, and utilized these cells for the screening of CaM antagonists. In the presence of Ca2+, CaM undergoes a conformational change exposing a hydrophobic pocket that interacts with CaM-binding proteins, peptides,
and drugs. This conformational change induced in CaM leads to a change in the microenvironment of EGFP, resulting in a change
in its fluorescence intensity. The observed change in fluorescence intensity of EGFP can be correlated to the concentration
of the analyte present in the sample. Dose-response curves for various tricyclic antidepressants were generated using cells
containing CaM-EGFP fusion protein. Additionally, we demonstrate the versatility of our system for studying protein-protein
interactions by using cells to study the binding of a peptide to CaM. The study showed that the CaM-EGFP fusion protein within
the intact cells responds similarly to that of the isolated fusion protein, hence eliminating the need for any isolation and
purification steps. We have demonstrated that this system can be used for the rapid screening of various CaM antagonists that
are potential antipsychotic drugs. 相似文献
202.
Synthesis of 4,5‐Dihydrofuran‐3‐carbonitrile Derivatives with Electron‐Rich Alkenes in the Presence of Manganese(III) Acetate 下载免费PDF全文
Radical cyclization reactions mediated by manganese(III) acetate were carried out with ν‐excessive alkenes ( 2a‐d ) and 3‐oxopropanenitriles ( 1a‐f ) resulting in the formation of 3‐cyano‐4,5‐dihydrofuran derivatives in poor to high yields. A mechanism was proposed for the cyclization reaction. The significance of the study is the formation of the 3‐cyano‐4,5‐dihydrofuran derivatives resembling terfuran, 2‐(2‐thienyl)furan and 2‐(2‐benzofuryl)furyl compounds having the fluorescent properties due to a conjugated ν‐electron system particularly containing the cyano moeity. 相似文献
203.
In this work, a boron‐doped diamond (BDD) electrode was used for the electroanalytical determination of indole‐3‐acetic acid (IAA) phytohormone by square‐wave voltammetry. IAA yielded a well‐defined voltammetric response at +0.93 V (vs. Ag/AgCl) in Britton–Robinson buffer, pH 2.0. The process could be used to determine IAA in the concentration range of 5.0 to 50.0 µM (n=8, r=0.997), with a detection limit of 1.22 µM. The relative standard deviation of ten measurements was 2.09 % for 20.0 µM IAA. As an example, the practical applicability of BDD electrode was tested with the measurement of IAA in some plant seeds. 相似文献
204.
Emre Cevik Alaaddin Cerit Huseyin Tombuloglu Hussein Sabit Huseyin Bekir Yildiz 《Analytical letters》2019,52(7):1138-1152
The fabrication of amperometric biosensors based on whole cell Gluconobacter oxydans DSMZ 2343 (G. oxydans) and glucose oxidase (GOx) was performed for the detection of glucose. Glassy carbon electrodes (GCE) were coated with a 10-(4H-dithiyeno [3,2-b:2’,3’-d]pyroll-4-il)decan-1-amine (DTP-alkyl-NH2) polymer using an electropolymerization method and the formed interface was used to connect the bacteria and the enzyme to the electrode. The transfer of electrons from enzyme to electrode was successfully demonstrated by the biocatalytic activity and unique morphology of the conducting polymer. Characterization of the biosensors was assessed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) analyses. The detection limits of the enzyme and microbial based biosensors for glucose were 0.022 and 0.081?mM, respectively. The broad linear dynamic ranges of the GOx and G. oxydans biosensors were observed to be 0.045–50.0 and 0.19–50.0?mM, respectively. The analytical performances of biosensors were compared according to the following figures of merit: detection limits, limits of quantification, pH and current response time. In addition, to demonstrate the applicability of the biosensors, real-time measurements and recovery studies were evaluated. 相似文献
205.
eref Demirayak Zafer ahin Merve Erta Emre Fatih Bülbül Ceysu Bender Sevde Nur Biltekin Barkin Berk Begüm Nurpelin Salk Serkan Levent Leyla Yurtta 《Journal of heterocyclic chemistry》2019,56(12):3370-3386
Dementia is a cognitive disorder mostly associated with Alzheimer's disease (AD) in addition to being seen in many other diseases of the central nervous system (CNS). The limited number of drugs is not sufficient to provide adequate improvement to increase the quality of life of patients suffering from this symptom; therefore, all treatment options should be evaluated in detail. In this study, new molecules, [2‐(4‐(2/3/4‐substituted phenyl)piperazin‐1‐yl)‐4‐phenylthiazol‐5‐yl][3/4‐substituted phenyl]methanone derivatives ( 1‐44 ), were obtained and analyzed in terms of their anticholinesterase activities. Kinetic mode and molecular interactions were also evaluated. An enzyme inhibition study was undertaken on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) using the Ellman method. Maestro program was used in molecular modeling studies. Forty‐four compounds were evaluated on AChE and BChE enzymes at 10?3 and 10?4 concentrations. The inhibition concentrations were calculated as 0.268μM to 2.104μM for six compounds ( 4 , 5 , 16 , 27 , 37 , and 38 ) on AChE. Compound 5 including the 4‐methoxy substituent (IC50: 0.268μM) and compound 38 containing the 4‐methoxy and 3‐methyl substituents (IC50: 0.286μM) showed the highest AChE inhibitory activity. They were further examined in terms of hydrogen bonding with Arg296 and Ar‐Ar interaction with Trp286. The activity of compound 5 was also assessed in mixed‐type kinetic mode. 相似文献
206.
Photocatalytic Hydrogen Evolution by Oleic Acid‐Capped CdS,CdSe, and CdS0.75Se0.25 Alloy Nanocrystals 下载免费PDF全文
Emre Aslan Okan Birinci Abdalaziz Aljabour Faruk Özel Ilker Akın Dr. Imren Hatay Patir Dr. Mahmut Kus Prof. Dr. Mustafa Ersoz 《Chemphyschem》2014,15(13):2668-2671
Photocatalytic generation of hydrogen by using oleic acid‐capped CdS, CdSe, and CdS0.75Se0.25 alloy nanocrystals (quantum dots) has been investigated under visible‐light irradiation by employing Na2S and Na2SO3 as hole scavengers. Highly photostable CdS0.75Se0.25 alloy nanocrystals gave the highest hydrogen evolution rate (1466 μmol h?1 g?1), which was about three times higher than that of CdS and seven times higher than that of CdSe. 相似文献
207.
208.
The polymerization of methyl methacrylate MMA catalyzed by [Mo(CO)4L2] [L2 = diphenylphosphinomethane (dppm), diphenylphosphinoethane (dppe) or diphenylphosphinopropane (dppp)] has been studied. The activity of these single‐component catalysts depends on the length of the (CH2)n bridge of diphosphine ligand. Thus, the dppm derivative displays higher activity than dppe or dppp ligands. These complexes, as free radical initiators, afforded the methyl methacrylate polymerization in chlorinated solvents. The mechanism of the polymerization was discussed and a radical mechanism was proposed. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
209.
X‐ray nanotomography and focused‐ion‐beam sectioning for quantitative three‐dimensional analysis of nanocomposites 下载免费PDF全文
Christopher E. Shuck Mathew Frazee Andrew Gillman Matthew T. Beason Ibrahim Emre Gunduz Karel Matouš Robert Winarski Alexander S. Mukasyan 《Journal of synchrotron radiation》2016,23(4):990-996
Knowing the relationship between three‐dimensional structure and properties is paramount for complete understanding of material behavior. In this work, the internal nanostructure of micrometer‐size (~10 µm) composite Ni/Al particles was analyzed using two different approaches. The first technique, synchrotron‐based X‐ray nanotomography, is a nondestructive method that can attain resolutions of tens of nanometers. The second is a destructive technique with sub‐nanometer resolution utilizing scanning electron microscopy combined with an ion beam and `slice and view' analysis, where the sample is repeatedly milled and imaged. The obtained results suggest that both techniques allow for an accurate characterization of the larger‐scale structures, while differences exist in the characterization of the smallest features. Using the Monte Carlo method, the effective resolution of the X‐ray nanotomography technique was determined to be ~48 nm, while focused‐ion‐beam sectioning with `slice and view' analysis was ~5 nm. 相似文献
210.
In this study, copper (Cu), zinc (Zn), manganese (Mn), iron (Fe), magnesium (mg), nickel (Ni), chrome (Cr), cobalt (Co) and boron (B) accumulation ratios of muscle, skin and gill of Striped seabream (Sparidae, Lithognathus mormyrus), Golden grey mullet (Mugilidae, Liza aurata), Thicklip grey mullet (Mugilidae, Chelon labrasus), Flathead mullet (Mugilidae, Mugil cephalus), Gilthead seabream (Sparidae, Sparus aurata) and Thinlip mullet (Mugilidae, Liza ramada) in Beymelek Lagoon (Antalya/Turkey) were investigated. The analyses of elements were performed with inductively coupled plasma-optic emission spectroscopy (ICP-OES) by using microwave digestion techniques. There were significant variations among heavy metal accumulation levels of the species and their tissues. The heavy metal concentrations found in tissues varied for Cu: 0.28-5.11, Zn: 4.27-339.76, Mn: 0.0-12.81, Fe: 3.25-117.73, Cr: 0.0-1.40, Co: 0.0-3.29 and Mg: 168.73-659.16 mg/kg wet weight. Ni and B were not detected in any tissues of the species. The heavy metal concentrations of fish in Beymelek Lagoon were lower than those of fish from other contaminated Mediterranean regions of Turkey. This research showed that heavy metal concentrations in muscles of investigated species were also lower than the maximum levels set by law. 相似文献