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51.
Functional expression and purification of bovine enterokinase light chain in recombinant Escherichia coli 总被引:2,自引:0,他引:2
Enterokinase (EC 3.4.21.9) is a serine proteinase of the intestinal brush border that exhibits specificity for the sequence (Asp)(4)-Lys and converts trypsinogen into its active form, trypsin. A codon optimized sequence coding light chain (catalytic subunit) of bovine enterokinase gene (sBEKLC) was synthesized, and it was fused with DsbA to construct the expression vector (pET39-sBEKLC). Then, the plasmid was transformed into E. coli BL21 (DE3) for expression. Under optimal conditions, the volumetric productivity of fusion protein reached 151.2 mg L(-1), i.e., 80.6 mg sBEKLC L(-1). The cold osmotic shock technique was successfully used to extract sBEKLC from periplasmic space, and nickel affinity chromatography was employed to obtain mature sBEKLC. Finally, about 6.8 mg of bioactive sBEKLC was purified from 1 liter fermentation broth and could be used to cleave one tested fusion protein with an inter-domain enteropeptidase recognition site. This work will be helpful for large-scale production of this increasingly demanded enterokinase. 相似文献
52.
Hu Xiao-Kun Lin Zhuo-Ru Zhang Qing-Chun Kong Fan-Zhou Cen Jing-Yi Zeng Yu-Lan Yu Ren-Cheng 《Journal of applied phycology》2022,34(3):1483-1496
Journal of Applied Phycology - The dinoflagellates Karenia mikimotoi and Prorocentrum donghaiense are both important causative species of harmful algal blooms (HABs) in the East China Sea. The... 相似文献
53.
Xiao Xiaolan Sun Shuangxi Li Yingbin Cen Xuecheng Wu Shibiao Lu Aili Cai Jun Zhao Junjie Li Shaoxue 《Molecular biology reports》2022,49(7):6303-6311
Molecular Biology Reports - Oxidative stress and neurocyte apoptosis are crucial pathophysiological process in early brain injury (EBI) after subarachnoid hemorrhage (SAH). Geniposide (GNP) has... 相似文献
54.
Danfeng?Dong Zhen?Li Lihua?Zhang Cen?Jiang Enqiang?Mao Xuefeng?WangEmail author Yibing?PengEmail author 《Mycopathologia》2015,180(5-6):407-419
In this study, fungemia cases from four tertiary hospitals located in Shanghai and Anhui province in China from March 2012 to December 2013 were enrolled to investigate clinical features, species distribution, antifungal susceptibility and strain relatedness. During the study period, 137 non-duplicate cases and their corresponding isolates were collected. Six different genera of fungi were identified, of which Candida spp. were the most common (126/137, 91.97 %), with C. albicans predominating (48/137, 35.03 %). The non-Candida fungi rate reached 8.03 % (11/137), and Pichia spp. was the most common (5/137, 3.65 %). Compared with C. albicans, non-C. albicans fungi-associated fungemia was more likely in younger (p = 0.004) and male patients (χ 2 = 6.2618, p = 0.0123) and patients from ICUs (χ 2 = 6.3783, p = 0.0116). Overall, the susceptible/WT rates of common Candida spp. to fluconazole, itraconazole, voriconazole, flucytosine, amphotericin B and caspofungin were 74.63, 92.31, 93.16, 96.58, 100 and 95.69 %, respectively. C. tropicalis and C. guilliermondii had a low susceptibility to fluconazole: 79.95 and 77.78 %, respectively. No isolates were resistant/WT to caspofungin, but C. parapsilosis and C. guilliermondii had high MIC90 values; 1 and 2 mg/L, respectively. In terms of genotyping, MLST was taken for C. glabrata and C. tropicalis, while microsatellite marker analysis was used for C. albicans and C. parapsilosis. C. glabrata was predominantly clone ST7, accounting for 75 %, while the other isolates showed genetic diversity. Considering the increased proportion of non-C. albicans fungi and the presence of endemic clones of C. glabrata, it is essential to undertake additional surveillance of fungemia. 相似文献
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Linfang Shen Xudong Chen Xufeng Zhang Krishna Agarwal 《Plasmonics (Norwell, Mass.)》2011,6(2):301-305
In this paper, we show that surface plasmon polaritons (SPPs) can be sustained by a single row of holes periodically drilled
on a perfect electric conductor surface. These SPPs can be strongly confined in the transverse plane and they possess an excellent
modal shape. In the terahertz regime, large propagation length is available for highly confined SPPs on a real-metal surface
waveguide. As the dispersion characteristics of such SPPs can be controlled by the surface geometry, unusual total reflection
phenomenon occurs when waves travel along a nonuniform surface waveguide with gradually increasing hole depths. 相似文献
58.
Xie C Yang S Zhong D Dai X Chen X 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(28):3071-3075
Dronedarone is a derivative of amiodarone--a popular antiarrhythmic drug. It was developed to overcome the limiting iodine-associated toxicities of amiodarone. Debutyldronedarone is a major circulating active metabolite of dronedarone in humans. To investigate the pharmacokinetics of dronedarone, a rapid, simple, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determine dronedarone and debutyldronedarone in human plasma using amiodarone as internal standard (IS). Acetonitrile with IS was used to precipitate proteins from a 50-μL aliquot of plasma. Effective chromatographic separation was performed on a CAPCELL PAK C(18) MG (100 mm × 4.6 mm, 5 μm) column with gradient elution (5 mmol/L ammonium acetate-acetonitrile, with each phase containing 0.2% acetic acid) at a flow rate of 0.7 mL/min. Complete separation was achieved within 5.5 min. Detection was carried out on an tandem mass spectrometer in multiple reaction monitoring mode using a positive atmospheric pressure chemical ionization interface. A lower limit of quantification of 0.200 ng/mL was achieved for both dronedarone and debutyldronedarone, with acceptable precision and accuracy. The linear range of the method was from 0.200 to 200 ng/mL for each analyte. Intra- and inter-day precisions were lower than 7.2% in relation to relative standard deviation, while accuracy was within ±5.1% in terms of relative error for analytes. Our findings demonstrate the successful application of the validated LC-MS/MS method to a pharmacokinetic study after a single oral administration of 400mg dronedarone to six healthy volunteers. 相似文献
59.
Functional mapping has been a powerful tool in mapping quantitative trait loci (QTL) underlying dynamic traits of agricultural or biomedical interest. In functional mapping, multivariate normality is often assumed for the underlying data distribution, partially due to the ease of parameter estimation. The normality assumption however could be easily violated in real applications due to various reasons such as heavy tails or extreme observations. Departure from normality has negative effect on testing power and inference for QTL identification. In this work, we relax the normality assumption and propose a robust multivariate t-distribution mapping framework for QTL identification in functional mapping. Simulation studies show increased mapping power and precision with the t distribution than that of a normal distribution. The utility of the method is demonstrated through a real data analysis. 相似文献
60.
Efficient production of a soluble fusion protein containing human beta-defensin-2 in E. coli cell-free system 总被引:6,自引:0,他引:6
Human beta-defensin-2 (hBD2), a small cationic peptide, exhibits a broad range of antimicrobial activity and does not cause microbial resistance. In order to produce hBD2 efficiently, an Escherichia coli cell-free biosynthesis system has been developed as an alternative method. A specific plasmid pIVEX2.4c-trxA-shBD2 was constructed for the cell-free expression of fusion protein (hBD2 linked with His-Tag and Trx-Tag). This allowed enhancement of protein stability and facilitated downstream purification process. Significant amount of target fusion protein was synthesized in the batch-mode bioreactor by optimizing the reaction conditions. About five-fold improvement of productivity (ca. 2.0 mg/ml soluble fusion protein) could be achieved by using a continuous exchange cell-free (CECF) system compared to batch system. One-step affinity chromatographic process was developed to recover high purity fusion protein (95.2%) with overall recovery ratio of about 50%. The fusion protein was cleaved by cyanogens bromide (CNBr), and the mature hBD2 had demonstrated strong inhibition on the growth of E. coli D31 at low concentration. 相似文献