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171.
Thiopental (TPL) is a commonly used barbiturate anesthetic. Its binding with human serum albumin (HSA) was studied to explore the anesthetic-induced protein dysfunction. The basic binding interaction was studied by UV-absorption and fluorescence spectroscopy. An increase in the binding affinity (K) and in the number of binding sites (n) with the increasing albumin concentration was observed. The interaction was conformation-dependent and the highest for the F isomer of HSA, which implicates its slow elimination. The mode of binding was characterized using various thermodynamic parameters. Domain II of HSA was found to possess a high affinity binding site for TPL. The effect of micro-metal ions on the binding affinity was also investigated. The molecular distance, r, between donor (HSA) and acceptor (TPL) was estimated by fluorescence resonance energy transfer (FRET). Correlation between the stability of the TPL-N and TPL-F complexes and drug distribution is discussed. The structural changes in the protein investigated by circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy reflect perturbation of the albumin molecule and provide an explanation for the heterogeneity of action of this anesthetic. 相似文献
172.
Solid state production of polygalacturonase and xylanase by Trichoderma species using cantaloupe and watermelon rinds 总被引:1,自引:0,他引:1
Saleh A. Mohamed Abdulrahman L. Al-Malki Jalaluddin A. Khan Saleh A. Kabli Saleh M. Al-Garni 《Journal of microbiology (Seoul, Korea)》2013,51(5):605-611
Different solid state fermentation (SSF) sources were tested such as cantaloupe and watermelon rinds, orange and banana peels, for the production of polygalacturonase (PG) and xylanase (Xyl) by Trichoderma harzianum and Trichoderma virens. The maximum production of both PG and Xyl were obtained by T. harzianum and T. virnes grown on cantaloupe and watermelon rinds, respectively. Time course, moisture content, temperature, pH, supplementation with carbon and nitrogen sources were optimized to achieve the maximum production of both PG and Xyl of T. harzianum and T. virens using cantaloupe and watermelon rinds, respectively. The maximum production of PG and Xyl of T. harzianum and T. virens was recorded at 4–5 days of incubation, 50–66% moisture, temperature 28–35°C and pH 6–7. The influence of supplementary carbon and nitrogen sources was studied. For T. harzianum, lactose enhanced PG activity from 87 to 120 units/g solid, where starch and maltose enhanced Xyl activity from 40 to 55–60 units/g solid for T. virnes. Among the nitrogen sources, ammonium sulphate, ammonium nitrate, yeast extract and urea increased PG activity from 90 to 110–113 units/g solid for T. harzianum. Similarly, ammonium chloride, ammonium sulphate and yeast extract increased Xyl activity from 45 to 55–70 units/g solid for T. virens. 相似文献
173.
Roselani I. Henry Simon A. Cobbold Richard J. W. Allen Asif Khan Rhys Hayward Adele M. Lehane Patrick G. Bray Susan M. Howitt Giancarlo A. Biagini Kevin J. Saliba Kiaran Kirk 《The Journal of biological chemistry》2010,285(24):18615-18626
The intraerythrocytic malaria parasite exerts tight control over its ionic composition. In this study, a combination of fluorescent ion indicators and 36Cl− flux measurements was used to investigate the transport of Cl− and the Cl−-dependent transport of “H+-equivalents” in mature (trophozoite stage) parasites, isolated from their host erythrocytes. Removal of extracellular Cl−, resulting in an outward [Cl−] gradient, gave rise to a cytosolic alkalinization (i.e. a net efflux of H+-equivalents). This was reversed on restoration of extracellular Cl−. The flux of H+-equivalents was inhibited by 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid and, when measured in ATP-depleted parasites, showed a pronounced dependence on the pH of the parasite cytosol; the flux was low at cytosolic pH values < 7.2 but increased steeply with cytosolic pH at values > 7.2. 36Cl− influx measurements revealed the presence of a Cl− uptake mechanism with characteristics similar to those of the Cl−-dependent H+-equivalent flux. The intracellular concentration of Cl− in the parasite was estimated to be ∼48 mm in situ. The data are consistent with the intraerythrocytic parasite having in its plasma membrane a 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid-sensitive transporter that, under physiological conditions, imports Cl− together with H+-equivalents, resulting in an intracellular Cl− concentration well above that which would occur if Cl− ions were distributed passively in accordance with the parasite''s large, inwardly negative membrane potential. 相似文献
174.
Frédéric Pinel Bernabé Dorronsoro Johnatan E. Pecero Pascal Bouvry Samee U. Khan 《Cluster computing》2013,16(3):421-433
The sensitivity analysis of a Cellular Genetic Algorithm (CGA) with local search is used to design a new and faster heuristic for the problem of mapping independent tasks to a distributed system (such as a computer cluster or grid) in order to minimize makespan (the time when the last task finishes). The proposed heuristic improves the previously known Min-Min heuristic. Moreover, the heuristic finds mappings of similar quality to the original CGA but in a significantly reduced runtime (1,000 faster). The proposed heuristic is evaluated across twelve different classes of scheduling instances. In addition, a proof of the energy-efficiency of the algorithm is provided. This convergence study suggests how additional energy reduction can be achieved by inserting low power computing nodes to the distributed computer system. Simulation results show that this approach reduces both energy consumption and makespan. 相似文献
175.
DENS: data center energy-efficient network-aware scheduling 总被引:1,自引:0,他引:1
In modern data centers, energy consumption accounts for a considerably large slice of operational expenses. The existing work in data center energy optimization is focusing only on job distribution between computing servers based on workload or thermal profiles. This paper underlines the role of communication fabric in data center energy consumption and presents a scheduling approach that combines energy efficiency and network awareness, named DENS. The DENS methodology balances the energy consumption of a data center, individual job performance, and traffic demands. The proposed approach optimizes the tradeoff between job consolidation (to minimize the amount of computing servers) and distribution of traffic patterns (to avoid hotspots in the data center network). 相似文献
176.
M Tanweer Khan Sylvia H Duncan Alfons J M Stams Jan Maarten van Dijl Harry J Flint Hermie J M Harmsen 《The ISME journal》2012,6(8):1578-1585
Faecalibacterium prausnitzii is one of the most abundant bacteria in the human gut ecosystem and it is an important supplier of butyrate to the colonic epithelium. Low numbers of faecalibacteria have been associated with inflammatory bowel disease. Despite being extremely oxygen sensitive, F. prausnitzii is found adherent to the gut mucosa where oxygen diffuses from epithelial cells. This paradox is now explained on the basis of gas tube experiments, flavin-dependent reduction of 5,5′-dithiobis-2-nitrobenzoate and microbial fuel cell experiments. The results show that F. prausnitzii employs an extracellular electron shuttle of flavins and thiols to transfer electrons to oxygen. Both compounds are present in the healthy human gut. Our observations may have important implications for the treatment of patients with Crohn''s disease, for example, with flavin- or antioxidant rich diets, and they provide a novel key insight in host–microbe interactions at the gut barrier. 相似文献
177.
Inverted Tandem Polymer Solar Cells with Polyethylenimine‐Modified MoOX/Al2O3:ZnO Nanolaminate as the Charge Recombination Layers 下载免费PDF全文
Jae Won Shim Canek Fuentes‐Hernandez Yinhua Zhou Amir Dindar Talha M. Khan Anthony J. Giordano Hyeunseok Cheun Minseong Yun Seth R. Marder Bernard Kippelen 《Liver Transplantation》2014,4(10)
A new charge recombination layer for inverted tandem polymer solar cells is reported. A bilayer of MoOX/Al2O3:ZnO nanolaminate is shown to enable efficient charge recombination in inverted tandem cells. A polymer surface modification on the MoOX/Al2O3:ZnO nanolaminate bilayer increases the work function contrast between the two outward surfaces of the charge recombination layer, further improving the performance of tandem solar cells. An analysis of the electrical, optical, and surface properties of the charge recombination layer is presented. Inverted tandem polymer solar cells, with two photoactive layers comprising poly (3‐hexylthiophene) (P3HT):indene‐C60 bisadduct (IC60BA) for the bottom cell and poly[(4,8‐bis‐(2‐ethylhexyloxy)‐benzo[1,2‐b:4,5‐b']dithiophene)‐2,6‐diyl‐alt‐(4‐(2‐ethylhexanoyl)‐thieno[3,4‐b]thiophene))‐2,6‐diyl] (PBDTTT‐C):[6,6]‐phenyl C61 butyric acid methyl ester (PC60BM) for the top cell, yield an open‐circuit voltage of 1481 mV ± 15 mV, a short‐circuit current density of 7.1 mA cm?2 ± 0.1 mA cm?2, and a fill factor of 0.62 ± 0.01, resulting in a power conversion efficiency of 6.5% ± 0.1% under simulated AM 1.5G, 100 mW cm?2 illumination. 相似文献
178.
Yousafi Qudsia Amin Humaira Bibi Shabana Rafi Rafea Khan Muhammad S. Ali Hamza Masroor Ashir 《International journal of peptide research and therapeutics》2021,27(4):2685-2701
International Journal of Peptide Research and Therapeutics - Klebsiella oxytoca is a gram-negative bacterium. It is opportunistic in nature and causes hospital acquired infections.... 相似文献
179.
180.
Marcellous Le Roux Ethel Phiri Wesaal Khan Muhammet Şakiroğlu Alex Valentine Sehaam Khan 《Journal of plant physiology》2014
During P deficiency, the increased activity of malate dehydrogenase (MDH, EC 1.1.1.37) can lead to malate accumulation. Cytosolic- and nodule-enhanced MDH (cMDH and neMDH, respectively) are known isoforms, which contribute to MDH activity in root nodules. The aim of this study was to investigate the role of the cMDH isoforms in nodule malate supply under P deficiency. Nodulated lupins (Lupinus angustifolius var. Tanjil) were hydroponically grown at adequate P (+P) or low P (−P). Total P concentration in nodules decreased under P deficiency, which coincided with an increase in total MDH activity. A consequence of higher MDH activity was the enhanced accumulation of malate derived from dark CO2 fixation via PEPC and not from pyruvate. Although no measurable neMDH presence could be detected via PCR, gene-specific primers detected two 1 kb amplicons of cMDH, designated LangMDH1 (corresponding to +P, HQ690186) and LangMDH2 (corresponding to −P, HQ690187), respectively. Sequencing analyses of these cMDH amplicons showed them to be 96% identical on an amino acid level. There was a high degree of diversification between proteins detected in this study and other known MDH proteins, particularly those from other leguminous plants. Enhanced malate synthesis in P-deficient nodules was achieved via increased anaplerotic CO2 fixation and subsequent higher MDH activities. Novel isoforms of cytosolic MDH may be involved, as shown by gene expression of specific genes under P deficiency. 相似文献