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排序方式: 共有323条查询结果,搜索用时 312 毫秒
261.
Dilek Din?ol Ali Arican Arzu Ensari Serdar Akyar Yaar Bedük Abdülkadir Cengiz 《Cancer immunology, immunotherapy : CII》1999,16(2):134-138
A 53-year-old man with triple renal neoplasms in his left kidney presented. He was initially diagnosed intermediate grade
non-Hodgkin’s lymphoma (NHL) which involved gastro-intestinal tract, left kidney, liver and pancreas. He underwent left nefrectomy
because of a persistent renal mass after the completion of chemotherapy. The large renal mass revealed a renal cell carcinoma
(RCC). Additionally, multiple small nodules of non-Hodgkin’s lymphoma and a solitary leiomyoma were observed. 相似文献
262.
Purification and properties of ferredoxinTOL. A component of toluene dioxygenase from Pseudomonas putida F1 总被引:22,自引:0,他引:22
V Subramanian T N Liu W K Yeh C M Serdar L P Wackett D T Gibson 《The Journal of biological chemistry》1985,260(4):2355-2363
Toluene dioxygenase oxidizes toluene to (+)-cis-1(S),2(R)-dihydroxy-3-methylcyclohexa-3,5-diene. This reaction is catalyzed by a multienzyme system that is induced in cells of Pseudomonas putida F1 during growth on toluene. One of the components of toluene dioxygenase has been purified to homogeneity and shown to be an iron-sulfur protein that has been designated ferredoxinTOL. The molecular weight of ferredoxinTOL was calculated to be 15,300, and the purified protein was shown to contain 2 g of atoms each of iron- and acid-labile sulfur which appear to be organized as a single [2Fe-2S]cluster. Solutions of ferredoxinTOL were brown in color and showed absorption maxima at 277, 327, and 460 nm. A shoulder in the spectrum of the oxidized protein was discernible at 575 nm. Reduction with sodium dithionite or NADH and ferredoxinTOL reductase resulted in a decrease in visible absorbance at 460 and 575 nm, with a concomitant shift in absorption maxima to 382 and 438 nm. The redox potential of ferredoxinTOL was estimated to be -109 mV. In the oxidized state, the protein is diamagnetic. However, upon reduction it exhibited prominent electron paramagnetic resonance signals with anisotropy in g values (gx = 1.81, gy = 1.86, and gz = 2.01). Anaerobic reductive titrations revealed that ferredoxinTOL is a one-electron carrier that accepts electrons from NADH in a reaction that is mediated by a flavoprotein (ferredoxinTOL reductase). The latter is the first component in the toluene dioxygenase system. Reduced ferredoxinTOL can transfer electrons to cytochrome c or to a terminal iron-sulfur dioxygenase (ISP-TOL) which catalyzes the incorporation of molecular oxygen into toluene and related aromatic substrates. 相似文献
263.
Erol Ismail Kotil Seyfullah Enes Fidan Ozkan Yetiman Ahmet E. Durdagi Serdar Ortakci Fatih 《Probiotics and antimicrobial proteins》2023,15(1):17-29
Probiotics and Antimicrobial Proteins - The COVID-19 pandemic caused by a novel coronavirus (SARS-CoV-2) is a serious health concern in the twenty-first century for scientists, health workers, and... 相似文献
264.
Isolation and characterization of altered plasmids in mutant strains of Pseudomonas putida NCIB 9816 总被引:6,自引:0,他引:6
The ability of P. putida NCIB 9816 to grow with naphthalene (Nah+) and salicylate (Sal+) is correlated with the presence of an 83 kilobase (kb) conjugative plasmid, pDTG1. Derivatives of pDTG1 were obtained from cells after exposure to halogenated analogs of naphthalene or salicylate. The selection of mutants having a Nah-Sal- or a Nah-Sal+ phenotype could be enhanced by the addition of triphenyltetrazolium chloride to the indicator medium. Structurally modified plasmids were characterized by restriction endonuclease digestion and Southern hybridization experiments. The region of pDTG1 DNA that encodes the enzymes responsible for the conversion of naphthalene to salicylate was identified. The structural changes in mutant plasmids were correlated with the absence of essential enzymatic activities. 相似文献
265.
Upstream stimulatory factor-2 regulates steroidogenic factor-1 expression in endometriosis 总被引:1,自引:0,他引:1
266.
Durdagi S Mavromoustakos T Papadopoulos MG 《Bioorganic & medicinal chemistry letters》2008,18(23):6283-6289
For the first time, a set of experimentally reported [60] fullerene derivatives were subjected to the 3D-QSAR/CoMFA and CoMSIA studies. The aim of this study is to propose a series of novel [60] fullerene-based inhibitors with optimal binding affinity for the HIV-1 PR enzyme. The position of the template molecule at the cavity of HIV-1 PR was optimized and 3D QSAR models were developed. Relative contributions of steric/electrostatic fields of the 3D-QSAR/CoMFA and CoMSIA models have shown that steric effects govern the bioactivity of the compounds, but electrostatic interactions play also an important role.The de novo drug design Leapfrog simulations provided a series of novel compounds with predicted improved inhibition effect. 相似文献
267.
Korkmaz A Oter S Sadir S Topal T Uysal B Ozler M Ay H Akin A 《Neurochemical research》2008,33(1):160-166
Hyperbaric oxygen (HBO) is known to cause oxidative stress in several organs and tissues. Due to its high rate of blood flow
and oxygen consumption, the brain is one of the most sensitive organs to this effect. The present study was performed to elucidate
the relation of HBO exposure time to its oxidative effects in rats’ brain cortex tissue. For this purpose, 49 rats were randomly
divided into five groups. Except the control group, study groups were subjected to three atmospheres HBO for 30, 60, 90, and
120 min. Their cerebral cortex layer was taken immediately after exposure and used for analysis. Thiobarbituric acid reactive
substances (TBARS), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and nitrate–nitrite (NOX) levels were determined. TBARS and SOD levels were found to increase in a time-dependent manner. GSH-Px activity reflected
an inconsistent course. NOX levels were found to be increased only in the 120 min exposed group. The results of this study suggests that HBO induced
oxidative effects are strongly related with exposure time. 相似文献
268.
We have determined the plasma concentrations of copper, zinc, copper/zinc ratio, and carbonic anhydrase activity in horses
infected with Babesia equi. The study was conducted in 14 horses with the disease and 10 healthy animals that served as controls. The infection was
confirmed by the clinical manifestations of the disease and by Giemsa staining of thin blood smears showing the parasites
inside red blood cells. The horses with piroplasmosis had lower plasma levels of zinc, elevated copper, and increased activity
of carbonic anhydrase. Consequently, the copper/zinc ratio was also higher than in the healthy controls. 相似文献
269.
Sanders C Turkarslan S Lee DW Onder O Kranz RG Daldal F 《The Journal of biological chemistry》2008,283(44):29715-29722
Cytochrome c maturation (Ccm) is a post-translational and post-export protein modification process that involves ten (CcmABCDEFGHI and CcdA or DsbD) components in most Gram-negative bacteria. The absence of any of these components abolishes the ability of cells to form cytochrome c, leading in the case of Rhodobacter capsulatus to the loss of photosynthetic proficiency and respiratory cytochrome oxidase activity. Based on earlier molecular genetic studies, we inferred that R. capsulatus CcmF, CcmH, and CcmI interact with each other to perform heme-apocytochrome c ligation. Here, using functional epitope-tagged derivatives of these components coproduced in appropriate mutant strains, we determined protein-protein interactions between them in detergent-dispersed membranes. Reciprocal affinity purification as well as tandem size exclusion and affinity chromatography analyses provided the first biochemical evidence that CcmF, CcmH, and CcmI associate stably with each other, indicating that these Ccm components form a membrane-integral complex. Under the conditions used, the CcmFHI complex does not contain CcmG, suggesting that the latter thio-reduction component is not always associated with the heme ligation components. The findings are discussed with respect to defining the obligatory components of a minimalistic heme-apocytochrome c ligation complex in R. capsulatus. 相似文献
270.
Conducting-state properties of the KcsA potassium channel from molecular and Brownian dynamics simulations. 总被引:6,自引:0,他引:6
The mechanisms underlying transport of ions across the potassium channel are examined using electrostatic calculations and three-dimensional Brownian dynamics simulations. We first build open-state configurations of the channel with molecular dynamics simulations, by pulling the transmembrane helices outward until the channel attains the desired interior radius. To gain insights into ion permeation, we construct potential energy profiles experienced by an ion traversing the channel in the presence of other resident ions. These profiles reveal that in the absence of an applied field the channel accommodates three potassium ions in a stable equilibrium, two in the selectivity filter and one in the central cavity. In the presence of a driving potential, this three-ion state becomes unstable, and ion permeation across the channel is observed. These qualitative explanations are confirmed by the results of three-dimensional Brownian dynamics simulations. We find that the channel conducts when the ionizable residues near the extracellular entrance are fully charged and those near the intracellular side are partially charged. The conductance increases steeply as the radius of the intracellular mouth of the channel is increased from 2 A to 5 A. Our simulation results reproduce several experimental observations, including the current-voltage curves, conductance-concentration relationships, and outward rectification of currents. 相似文献