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161.
Mei Ling Xu Hyoung Jin Kim Don Yong Chang Hong-Jin Kim 《Journal of microbiology (Seoul, Korea)》2013,51(3):389-393
Acidic protein levels in the milk decrease markedly as lactation progresses, suggesting that it is an important part of the colostrum. However, little attention has been paid to their biological function. In this study, we isolated the acidic protein fraction of bovine colostrum (AFC, isoelectric point <5) by anion-exchange chromatography, and investigated the effect of its dietary intake on influenza A (H1N1) virus infection. 100% of mice infected with 1 LD50 of the virus survived when administered AFC for 14 days prior to infection, compared with 33% survival when administered phosphate buffered saline (PBS). Moreover, consumption of AFC reduced the weight loss associated with infection. We propose that dietary intake of AFC has a prophylactic effect on influenza A virus infection. 相似文献
162.
β‐arrestin 1 and 2 (also known as arrestin 2 and 3) are homologous adaptor proteins that regulate seven‐transmembrane receptor trafficking and signalling. Other proteins with predicted ‘arrestin‐like’ structural domains but lacking sequence homology have been indicated to function like β‐arrestin in receptor regulation. We demonstrate that β‐arrestin2 is the primary adaptor that rapidly binds agonist‐activated β2 adrenergic receptors (β2ARs) and promotes clathrin‐dependent internalization, E3 ligase Nedd4 recruitment and ubiquitin‐dependent lysosomal degradation of the receptor. The arrestin‐domain‐containing (ARRDC) proteins 2, 3 and 4 are secondary adaptors recruited to internalized β2AR–Nedd4 complexes on endosomes and do not affect the adaptor roles of β‐arrestin2. Rather, the role of ARRDC proteins is to traffic Nedd4–β2AR complexes to a subpopulation of early endosomes. 相似文献
163.
Seung Hyun Kim Sin-Duk Jang Ki Yong Lee Sang Hyun Sung 《Journal of enzyme inhibition and medicinal chemistry》2013,28(1):230-233
A methanolic extract of dried leaves of Polygala japonica Houtt (Polygalaceae) significantly attenuated nitric oxide production in lipopolysaccharide-simulated BV2 microglia. Five anthraquinones chrysophanol (1), emodin (2), aloe-emodin (3), emodin 8-O-β-D-glucopyranoside (4) and trihydroxy anthraquinone (5), and four flavonoids kaempferol (6), chrysoeriol (7), kaempferol 3-gentiobioside (8) and isorhamnetin (9) were isolated from the methanolic extract using bioactivity-guided fractionation. Among them, compounds 1–4, 6 and 7 showed significant inhibitory effect on lipopolysaccharide-induced nitric oxide production in BV2 microglia at the concentrations ranging from 1.0 to 100.0 μM. 相似文献
164.
A highly sensitive chemiluminescence (CL) immunoassay was incorporated into a low‐cost microfluidic paper‐based analytical device (μ‐PAD) to fabricate a facile paper‐based CL immunodevice (denoted as μ‐PCLI). This μ‐PCLI was constructed by covalently immobilizing capture antibody on a chitosan membrane modified μ‐PADs, which was developed by simple wax printing methodology. TiO2 nanoparticles coated multiwalled carbon nanotubes (TiO2/MWCNTs) were synthesized as an amplification catalyst tag to label signal antibody (Ab2). After sandwich‐type immunoreactions, the TiO2/MWCNTs were captured on the surface of μ‐PADs to catalyze the luminol‐p‐iodophenol‐H2O2 CL system, which produced an enhanced CL emission. Using prostate‐specific antigen as a model analyte, the approach provided a good linear response range from 0.001 to 20 ng/mL with a low detection limit of 0.8 pg/mL under optimal conditions. This μ‐PCLI showed good reproducibility, selectivity and stability. The assay results of prostate‐specific antigen in clinical serum samples were in good agreement with that obtained by commercially used electrochemiluminescence methods at the Cancer Research Center of Shandong Tumor Hospital (Jinan, Shandong Province, China). This μ‐PCLI could be very useful to realize highly sensitive, qualitative point‐of‐care testing in developing or developed countries. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
165.
Muhammad Naeem Khan Muhammad Rasul Jan Jasmin Shah Sang Hak Lee Young Ho Kim 《Luminescence》2013,28(6):915-921
A highly sensitive and simple method for identifying sulpiride in pharmaceutical formulations and biological fluids is presented. The method is based on increased chemiluminescence (CL) intensity of a luminol–H2O2 system in response to the addition of Cr (III) under alkaline conditions. The CL intensity of the luminol–H2O2–Cr (III) system was greatly enhanced by the addition of sulpiride and the CL intensity was proportional to the concentration of sulpiride in a sample solution. Various parameters affecting the CL intensity were systematically investigated and optimized for determination of the sulpiride in a sample. Under the optimum conditions, the CL intensity was proportional to the concentration of sulpiride in the range of 0.068–4.0 µg/mL, with a good correlation coefficient of 0.997. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 8.50 × 10‐6 µg/mL and 2.83 × 10‐5 µg/mL, respectively. The method presented here produced good reproducibility with a relative standard deviation (RSD) of 2.70% (n = 7). The effects of common excipients and metal ions were studied for their interference effect. The method was validated statistically through recovery studies and successfully applied for the determination of sulpiride in pure form, pharmaceutical preparations and spiked human plasma samples. The percentage recoveries were found to range from 99.10 to 100.05% for pure form, 98.12 to 100.18% for pharmaceutical preparations and 97.9 to 101.4% for spiked human plasma. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
166.
Robert Vince Mei Hua Carol A. Caperelli 《Nucleosides, nucleotides & nucleic acids》2013,32(11-12):1711-1718
Abstract Analogs of intermediates in the de novo purine nucleotide biosynthetic pathway were synthesized to study the binding requirements of the corresponding enzymes. Because of the instability of the natural stubstrates, such as phosphoribosylamine, the use of the structurally stable phosphonate moiety and the carbocyclic ribose yields ideal analogs for these studies. In addition, these analogs can act as potential inhibitors of the de novo pathway leading to the design of anticancer agents. Enzyme studies with GAR synthetase and GAR transformylase reveal that the title compounds can act as substrates or inhibitors of the de novo enzymes. 相似文献
167.
Mei Zeng Baofeng Chen Yufeng Qing Wenguang Xie Wantai Dang Mingcai Zhao 《Nucleosides, nucleotides & nucleic acids》2013,32(7):455-465
Glut9 is highly expressed in the human kidney proximal convoluted tubular and plays a crucial role in the regulation of plasma urate levels. The gene effects were stronger among women. Our results show that 17-β-estradiol (E2) through ER (estrogen receptor) β downregulates Glut9 protein expression on human renal tubular epithelial cell line (HK2). Intriguingly, E2 does not affect the expression of Glut9 mRNA. ERβ is linked to PTEN, the PTEN gene negatively regulates the PI3K/AKT pathway, and the PI3K/AKT pathway inhibition may lead to autophagy. Further study indicates that ERβ may affect the expression of Glut9 though autophagy. 相似文献
168.
William B. Parker Sue C. Shaddix Lucy M. Rose Phuong T. Pham Mei Hua Robert Vince 《Nucleosides, nucleotides & nucleic acids》2013,32(4):795-804
Abstract The metabolism of O6-propyl-carbovir and N6-propyl-carbovir, two selective inhibitors of HIV replication, has been evaluated in CEM cells. Both compounds were phosphorylated in intact cells to carbovir-5′-triphosphate. The metabolism of these two agents was inhibited by deoxycoformycin and mycophenolic acid, but not erythro-9-(2-hydroxy-3-nonyl)adenine. No evidence of the 5′-triphosphate of either compound was detected in CEM cells. 相似文献
169.
Jiannan Yang Zhaoying Liu Mei Li Xinghui Qiu 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2013,158(2):84-90
Quinoxaline derivatives (quinoxalines) comprise a class of drugs that have been widely used as animal antimicrobial agents and feed additives. Although the metabolism of quinoxaline drugs has been mostly studied using chicken liver microsomes, the biochemical mechanism of biotransformation of these chemicals in the chicken has yet to be characterized. In this study, using bacteria produced enzymes, we demonstrated that both CYP1A4 and CYP1A5 participate in the oxidative metabolism of quinoxalines. For CYP1A5, three hydroxylated metabolites of quinocetone were generated. In addition, CYP1A5 is able to hydroxylate carbadox. For CYP1A4, only one hydroxylated product of quinocetone on the phenyl ring was identified. Neither CYP1A5 nor CYP1A4 showed hydroxylation activity towards mequindox and cyadox. Our results suggest that CYP1A4 and CYP1A5 have different and somewhat overlapping substrate specificity in quinoxaline metabolism, and CYP1A5 represents a crucial enzyme in hydroxylation of both quinocetone and carbadox. 相似文献
170.
Sang Taek Jung 《Biotechnology and Bioprocess Engineering》2013,18(4):625-636
Antibody Fc region, a recruiter and a frontline commander in the combat against cancer and infectious pathogens, mediates potent immune effector functions by engaging Fc receptors and serum complement proteins. Recent studies indicate that the Fc region is particularly amenable to modifications that enhance potency and serum stability through amino acid substitution and glycan modification. In order to modulate the interaction of the Fc domain with Fc-binding ligands (FcγRs, C1q, and FcRn), various engineering strategies have been employed; these studies are discussed in this review. 相似文献