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81.
Elizabeth B. Agnew Richard H. Wilson Jean L. Grem Leonard Neckers Daoqin Bi Chris H. Takimoto 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,755(1-2)
A sensitive HPLC assay has been developed to determine the concentration of 17-(allylamino)-17-demethoxygeldanamycin (AAG) in human plasma over the concentration range of 12.5 to 2500 nM (7.33 to 1465 ng/mL). After the addition of 1000 nM geldanamycin as the internal standard, 1 mL samples of human plasma were subjected to solid-phase extraction, via Bond-Elut C18 cartridges, followed by analysis using an isocratic reversed-phase HPLC assay with UV detection. A Phenomenex Kingsorb, 3 micron, C18, 150×4.60 mm column and a Phenomenex Security Guard pre-column, C18 (ODS, Octadecyl), were used to achieve separation. AAG and GM were monitored at 334 and 308 nm, respectively, on a Hewlett-Packard 1050 Diode-Array Detector. The mobile phase, run at a flow-rate of 1 mL/min, was composed of 50% (v/v) 25 mM sodium phosphate (pH 3.00) with 10 mM triethylamine and 50% acetonitrile. HPLC effectively resolved AAG with retention times of 14.60
0.54 min and the internal standard geldanamycin at 10.72±0.38 min (n=15). This assay was able to measure plasma concentrations of AAG, the lower limit of quantitation being 12.5 nM, at a starting dose of 10 mg/m2 infused intravenously over 1 h in a Phase I clinical trial in adult patients with solid tumors. 相似文献
82.
泥鳅多糖清除活性氧和保护DNA链的作用 总被引:43,自引:0,他引:43
采用化学发光法和分光光度法在多种化学模拟体系中研究了泥鳅多糖清除活性氧的作用 ,并用化学发光法观察了泥鳅多糖对·OH导致DNA链损伤的抑制作用。结果表明 ,泥鳅多糖能够有效地清除O·-2 、·OH、H2 O2 等活性氧 ,对DNA链具有良好的保护作用 相似文献
83.
P. Li C. Z. Zhao Y. Q. Zhand X. M. Wang J. F. Wang F. Wang Y. R. Bi 《Biologia Plantarum》2017,61(4):741-750
Silicon (Si) could enhance plant tolerance to heavy metals; however, the mechanism of Si-mediated alleviation of cadmium (Cd) toxicity in Poa annua was not clear. In this study, we found that 100 μM Cd significantly inhibited the growth of Poa annua seedlings. Furthermore, Cd enhanced the H2O2 and malondialdehyde content. The activities of superoxide dismutase and ascorbate peroxidase were enhanced, but the catalase and peroxidase activities were reduced by Cd treatment. Cd also altered the activity and expression of glucose-6-phosphate dehydrogenase (G6PDH) in Poa annua roots. Application of Na3PO4, an inhibitor of G6PDH, decreased the activity of G6PDH, the expression of G6PDH, and increased the Cd toxicity, suggesting that G6PDH is involved in the regulation of oxidative stress induced by Cd. Application of 1 mM Si alleviated the inhibition of Cd on the growth of Poa annua seedlings. Si application not only led to reduced oxidative injuries but also decreased the accumulation of Cd in Poa annua seedlings under Cd stress. Furthermore, Si decreased the activity of G6PDH and the expression of G6PDH under Cd stress, which demonstrated that Si attenuates the Cd toxicity in Poa annua probably through decreasing the expression of G6PDH under Cd stress. When G6PDH was inhibited, the alleviation impact of Si on Cd stress was abolished. Taken together, these results demonstrated that the Cd tolerance in Poa annua enhanced by Si is mainly due to the decrease of Cd uptake in roots and lowering the oxidative stress induced by Cd. 相似文献
84.
Spectroscopic and in silico study of binding mechanism of cynidine‐3‐O‐glucoside with human serum albumin and glycated human serum albumin 下载免费PDF全文
The drug–serum albumin interaction plays a dominant role in drug efficacy and disposition. The glycation of serum albumin that occurs during diabetes may affect its drug‐binding properties in vivo. In order to evaluate the interactivity characteristics of cyanidin‐3‐O‐glucoside (C3G) with human serum albumin (HSA) and glycated human serum albumin (gHSA), this study was undertaken using multiple spectroscopic techniques and molecular modeling analysis. Time‐resolved fluorescence and the thermodynamic parameters indicated that the quenching mechanism was static quenching, and hydrogen bonding and Van der Waals force were the main forces. The protein fluorescence could be quenched by C3G, whereas the polarity of the fluorophore was not obviously changed. C3G significantly altered the secondary structure of the proteins. Furthermore, the interaction force that existed in the HSA–C3G system was greater than that in the gHSA–C3G system. Fluorescence excitation emission matrix spectra, red edge excitation shift, Fourier transform infrared spectroscopy and circular dichroism spectra provided further evidence that glycation could inhibit the binding between C3G and proteins. In addition, molecular modeling analysis supported the experimental results. The results provided more details for the application of C3G in the treatment of diabetes. 相似文献
85.
Effects of soil heterogeneity and clonal integration on Alternanthera philoxeroides populations with a radial ramet aggregation 下载免费PDF全文
Some clonal plants can spread their ramet populations radially, and soil heterogeneity and clonal integration may greatly affect the establishment of these types of populations. We constructed Alternanthera philoxeroides populations with a radial ramet aggregation, allowing old ramets of clonal fragments to concentrate in central pots and younger ramets to root in peripheral pots. The peripheral pots were supplemented either with three different levels (high, medium and low) of soil nutrients to simulate a heterogeneous soil environment, or only one medium level of soil nutrients to simulate a homogeneous environment. Stolon connections between the central older ramets and the peripheral younger ramets were left intact or severed to test the effect of clonal integration. The maintenance of stolon connection could induce the division of labor between different‐aged ramets, by increasing the root investment in central ramets and the above‐ground growth in peripheral ramets. The maintenance of stolon connection could improve the growth of the central and peripheral ramets, clonal fragments and even the whole population. However, the positive consequence in peripheral ramets and whole fragments was only detected in the high‐nutrient patch of heterogeneous treatment. In sum, in the population with the radial ramet aggregation, clonal integration can play a key role in the rapid recruitment of young ramets of A. philoxeroides fragments, as well as the expansion of the whole population. The magnitude of clonal integration also became more obvious in the peripheral young ramets and whole fragments that experienced high‐nutrient patches. 相似文献
86.
丙型肝炎病毒基因组部份NS5区蛋白基因在大肠杆菌中的表达 总被引:1,自引:0,他引:1
在大肠杆菌中表达了丙型肝炎病毒基因组NS5区A段和部份B段蛋白。NS5A蛋白溶于水,可经过GST亲和层析柱纯化;NS5B蛋白不溶于水,经PBS-Triton X-100洗涤,尿素溶解后,通过离子交换柱纯化。经SDS-PAGE和Westemblot分析,NS5A蛋白除在57kD左右有条带外,还有不同程度的降解产物;NS5B蛋白主要在58kD左右有条带出现。为查明表达蛋白抗体在病人血清中的分布,取9 相似文献
87.
88.
Different probiotic properties for Lactobacillus fermentum strains isolated from swine and poultry 总被引:2,自引:0,他引:2
Systematic procedures were used to evaluate the probiotic properties of Lactobacillus fermentum (L. fermentum) strains isolated from swine and poultry. The major properties included their capabilities to adhere to the intestinal epithelium of swine and poultry, the inhibition on pathogenic bacteria, and their tolerance to the gastric juice and bile salts. Results showed that L. fermentum strains from poultry digestive tract showed better adherence to the swine intestine and chicken crop epithelial cells as compared to those strains from the swine origin. In addition, six strains from poultry and one strain from swine showed adhesion specificity to their own intestinal epithelium. Four poultry isolates and one swine isolate were able to adhere to the epithelial cells from both swine and chicken. For gastric juice and bile tolerance, most of the strains isolated from swine or poultry were acid tolerant but less strains were bile intolerant. The spent culture supernatant (SCS) of these L. fermentum strains showed antagonistic effect against the indicator bacteria, such as Escherichia coli, Salmonella spp., Shigella sonnei and some enterotoxigenic Staphylococcus aureus. From the above studies, some L. fermentum strains isolated from poultry were found to have the probiotic properties required for use in animal feed supplement. This study suggested that poultry digestive tract may serve as potential source for the isolation of probiotic lactic acid bacteria. 相似文献
89.
Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes 总被引:3,自引:0,他引:3
Klionsky DJ Abeliovich H Agostinis P Agrawal DK Aliev G Askew DS Baba M Baehrecke EH Bahr BA Ballabio A Bamber BA Bassham DC Bergamini E Bi X Biard-Piechaczyk M Blum JS Bredesen DE Brodsky JL Brumell JH Brunk UT Bursch W Camougrand N Cebollero E Cecconi F Chen Y Chin LS Choi A Chu CT Chung J Clarke PG Clark RS Clarke SG Clavé C Cleveland JL Codogno P Colombo MI Coto-Montes A Cregg JM Cuervo AM Debnath J Demarchi F Dennis PB Dennis PA Deretic V Devenish RJ Di Sano F Dice JF Difiglia M 《Autophagy》2008,4(2):151-175
Research in autophagy continues to accelerate,(1) and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.(2,3) There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response. 相似文献
90.
Wenjuan Bi Zhiyuan Gu Yuanna Zheng Limin Wang Jing Guo Gang Wu 《Development, growth & differentiation》2013,55(9):744-754
The osteogenesis of bone marrow stromal cells (BMSCs) is of paramount importance for the repair of large‐size bone defects, which may be compromised by the dietary‐accumulated all‐trans retinoic acid (ATRA). We have shown that heterodimeric bone morphogenetic protein 2/7 (BMP2/7) could induce bone regeneration in a significantly higher dose‐efficiency in comparison with homodimeric BMPs. In this study, we evaluated the effects of ATRA and BMP2/7 on the proliferation, differentiation, mineralization and osteogenic genes. ATRA and BMP2/7 exhibited both antagonistic and synergistic effects on the osteogenesis of BMSCs. ATRA significantly inhibited proliferation and expression of osteocalcin but enhanced the activity of alkaline phosphatase of BMSCs. On day 21, 50 ng/mL BMP2/7 could antagonize the inhibitive effects of ATRA and significantly enhance osteogenesis of BMSCs. These findings suggested a promising application potential of heterodimeric BMP2/7 in clinic to promote bone regeneration for the cases with dietary accumulated ATRA. 相似文献