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981.
同步荧光光谱比率法检测过氧亚硝酸根及其清除剂的研究 总被引:1,自引:0,他引:1
利用同步荧光光谱建立了一种新的荧光比率法检测过氧亚硝酸根(ONOO-)及评价其清除剂的方法。酪氨酸自身有荧光,在pH 8.5的磷酸缓冲溶液中,酪氨酸与CO2和ONOO-反应生成强 荧光的酪氨酸二聚体,利用同步荧光光谱技术, 在荧光发射光谱中能同时获得酪氨酸单体(λem=364 nm)与二聚体的荧光峰(λem=406 nm),且两峰的荧光强度的比值与ONOO-的浓度呈计量相 关。结果表明荧光强度的比值不受实验参数改变的影响,与传统的荧光法相比,有利于扩大检测的线性范围,提高灵敏度。荧光强度的比值与ONOO-的浓度在1.60×10-7 mol·L-1~6.00× 10-6 mol·L-1范围内呈线性关系,线性相关系数为0.999,检测限为1.84×10-8 mol·L-1。对浓度为1.00×10-6 mol·L-1 ONOO- 平行测定8次,其相对标准偏差为2.4%。利用该法测得抗癌药米托蒽醌的IC50为0.065 μg·mL-1。方法简便易行,试剂廉价易得,体系稳定,可作为一种检测ONOO-及筛选其清除剂的方法。 相似文献
982.
在pH 7.2的Tris-HCl缓冲溶液中和聚乙二醇6000(PEG-6000)存在下,羊抗人抗凝血酶Ⅲ与抗凝血酶Ⅲ(AT-Ⅲ)发生免疫反应形成疏水性的免疫复合物微粒,导致体系的共振散射强度增强,在波长为368,491和538 nm处出现3个共振散射峰,其中491 nm处的峰最强。分别考察了pH、AT-Ⅲ和PEG-6000浓度、温育时间和温度、共存物质的影响。在选定条件下,AT-Ⅲ浓度在62.5~875 ng·mL-1范围内与491 nm处体系的散射强度呈良好的线性关系,其回归方程为ΔIRS=62.5c+1.36,相关系数为0.996,检出限为29.4 ng·mL-1。该方法简便、灵敏和选择性好,用于人血中AT-Ⅲ含量的测定,结果满意,回收率在90.2%~108.9%之间。 相似文献
983.
984.
Hany G. Attia Hassan A. Albarqi Ismail G. Said Omaish Alqahtani Mohamed A. EI Raey 《Molecules (Basel, Switzerland)》2022,27(14)
Helicobacter pylori (H. pylori) is a global health threat, and the World Health Organization has included H. pylori among 12 bacterial species that require high priority future strategies for the development of new antibiotics due mainly to its high rates of resistance. Metallic nanoparticles are known for their antimicrobial properties. The FDA (Food and Drug Administration) has approved zinc oxide nanoparticles (ZnONPs) as biocompatible antimicrobials. Green synthesis of ZnONPs was performed based on Oak galls extract (OGE) and was characterized by UV, IR, DLS, TEM, and SEM measurements. In addition, LC-MS/MS was used for the identification of OGE constituents. A checkerboard assay was used to evaluate the activity of synthesized Qi-ZnONPs and OGE against H. pylori, and their synergistic effects with amoxicillin were evaluated. LC-MS/MS analyses identified 20 compounds as major gallic acid conjugates. The ZnONPs had average particle sizes of 5.5 nm (DLS) and 7.99 nm (TEM). Both OGE and Qi-ZnONPs exhibited moderate activity against H. pylori. Amoxicillin and Qi-ZnONPs combinations (1:2 and 1:4 amoxicillin:/Qi-ZnONPs) significantly decreased the MIC90 by two-fold and four-fold, respectively, and FIC values for the combinations were more significant than with OGE alone. OGE is rich in phenolics. The synergism between Qi-ZnONPs and amoxicillin can provide an alternative safe agent of low cost to combat H. Pylori infections. 相似文献
985.
Aflatoxin B1 is one of the contamination indicators for food safety monitoring. The rapid and effective assessment and determination of AFB1 in food is of great importance to dietary safety. The lateral flow assay shows advantages in its simplicity, and rapidity, and provides a visual readout, while the available lateral flow assay for AFB1 requires a competitive format that produces readings inversely proportional to the AFB1 concentration, which is counterintuitive and may lead to a potential misinterpretation of the results. Herein, we developed a positive readout aptamer-based lateral flow strip (Apt-strip) for the detection of AFB1. This Apt-strip relies on the competition between AFB1 and fluorescein-labeled complementary DNA strands (FAM-cDNA) for affinity binding to limited aptamers against AFB1 (AFB1-Apt). In the absence of AFB1, AFB1-Apt hybridizes with FAM-cDNA. No signal at the T-line of the Apt-strip was observed. In contrast, AFB1-Apt binds to AFB1 in the sample, and then a part of the FAM-cDNA is hybridized with the free AFB1-Apt, at which time the other unreacted FAM-cDNA is captured by A35-Apt on the T-line. The signal was observed. This method achieved fast detection of AFB1 with a detection limit (DL) of 0.1 ng/mL, positive readout, and increased sensitivity. 相似文献
986.
Jie Gao Caihong Wang Jinhong Wang Prof. Dr. Hongliang Tan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(41):9629-9633
We here report a simple and efficient strategy of fabricating artificial multi-enzyme complex (MEC) based on the integration of natural enzyme with catalytic compartment. As a proof of concept, this strategy was demonstrated by selecting cholesterol oxidase (ChOx) and CeIII-based nanoscale coordination polymer (Ce-NCP) with peroxidase-like activity as the models, which forms ChOx@Ce-NCP. Benefitting from the confinement and sheltering effects of Ce-NCP, superior cascade activity and stability in harsh environments were achieved in ChOx@Ce-NCP. Meanwhile, the distinct advantage of ChOx@Ce-NCP has also been highlighted by its negligible substrate inhibition effect and adjustable mass ratio of building blocks. Upon the doping of TbIII in ChOx@Ce-NCP, a luminescent artificial MEC (ChOx@Ce-NCP:Tb) was further fabricated to drive a cascade amplified time-resolved fluorescent assay within a confined space, showing high sensitivity and specificity toward cholesterol. 相似文献
987.
Neethu K.S. Jayanthi Eswaran Theetharappan M. Bhuvanesh Nattamai S.P Neelakantan M.A. Kaveri M. Velusamy 《应用有机金属化学》2019,33(3)
Half‐sandwiched ruthenium (II) arene complexes with piano stool‐like geometry with the general formula [(p‐cymene)RuClL1] and [(p‐cymene)RuClL2] [where L1 = (Z)‐N′‐((1,3‐diphenyl‐1H‐pyrazol‐4‐yl)methylene)furan‐2‐carbohydrazide and L2 = (Z)‐N′‐((1,3‐diphenyl‐1H‐pyrazol‐4‐yl)methylene)thiophene‐2‐carbohydrazide] were synthesized and characterized. The single crystal X‐ray data revealed that the complexes belong to the same crystal system (monoclinic) with octahedral geometry, where the ruthenium atom is surrounded by hydrazone ligand coordinated through ON atoms, one chloride labile co‐ligand and the remaining three coordination sites covered by an electron cloud of p‐cymene moiety. The interaction between the complexes and DNA/bovine serum albumin (BSA) was evaluated using absorption and emission titration methods showing intercalative modes of interaction. The DNA cleavage ability of the complexes was checked by agarose gel electrophoresis method exhibiting the destruction of DNA duplex arrangement. To understand the interaction between ruthenium complex and DNA/BSA molecule, molecular docking studies were performed. In vitro cytotoxicity of the complexes was examined by the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay on human lung cancer cell line, A549, and found that at lower IC50, cell growth inhibition has occurred. Similarly, the IC50 values of the complexes treated with cancerous cell lines have produced a significant amount of lactase dehydrogenase and nitrite content in the culture medium, which were evaluated as apoptosis‐inducing factors, suggesting that the ruthenium (II) arene hydrazone complexes with pyrazole ligands have promising anticancer activities. 相似文献
988.
Liping Zhou Baxiong Wei Lvying Wu Jing Li Bin Zhu Lei Zhang 《Biomedical chromatography : BMC》2020,34(2):e4727
A potent xanthine oxidoreductase inhibitor (LS087) was recently proved to exhibit a similar hypouricemic potency to febuxostat. A hyperuricemia model induced by potassium oxonate and hypoxanthine was proposed in specific pathogen-free male Kunming mice, and the serum urea nitrogen, creatinine and uric acid levels were measured after oral administration of LS087. Furthermore, renal histopathology was conducted by staining with hematoxylin and eosin, periodic acid–Schiff and Masson's trichrome stains, respectively. The results showed that the levels of serum urea nitrogen and uric acid significantly decreased compared with the model group, but the level of creatinine showed no significant changes. The pathological abnormalities in kidney tubules were improved after LS087 administration. Ten metabolites (M1–M10) of LS087 were identified after a single oral dosing of 10 mg/kg in rats. M6 was the primary LS087 metabolite in vivo with a pathway of methylation. The toxicity and potential risks of LS087 and its metabolites were predicted using the ProTox-II software. LS087 and the major metabolites (M2, M3, M5, M6, M7 and M8) were predicted to have no potential hepatotoxicity, but some metabolites with a total rate of <1% (M1, M4, M9, and M10) showed potential hepatotoxicity. M1 and M8 showed potential carcinogenicity. The LS087 biotransformation pathway in rat was well characterized. 相似文献
989.
Maria Tenje Hongyan Xia Mikael Evander Björn Hammarström Axel Tojo Sándor Belák Thomas Laurell Neil LeBlanc 《Analytica chimica acta》2015
In this study, we show a significantly reduced assay time and a greatly increased bead recovery for a commercial Luminex-based multiplex diagnostic immunoassay by performing all liquid handling steps of the assay protocol in a non-contact acoustic trapping platform. 相似文献
990.
Vi Tran Bernd Walkenfort Matthias Knig Mohammad Salehi Sebastian Schlücker 《Angewandte Chemie (International ed. in English)》2019,58(2):442-446
The design of a portable Raman/SERS‐LFA reader with line illumination using a custom‐made fiber optic probe for rapid, quantitative, and ultrasensitive point‐of‐care testing (POCT) is presented. The pregnancy hormone human chorionic gonadotropin (hCG) is detectable in clinical samples within only 2–5 s down to approximately 1.6 mIU mL?1. This acquisition time is several orders of magnitude shorter than those of existing approaches requiring expensive Raman instrumentation, and the method is 15‐times more sensitive than a commercially available lateral flow assay (LFA) as the gold standard. The SERS‐LFA technology paves the way for affordable, quantitative, and ultrasensitive POCT with multiplexing potential in real‐world applications, ranging from clinical chemistry to food and environmental analysis as well as drug and biowarfare agent testing. 相似文献