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991.
Minqin R Rajendran R Pan N Tan BK Ong WY Watt F Halliwell B 《Free radical biology & medicine》2005,38(9):1206-1211
Several epidemiological studies have suggested that increased iron stores are associated with increased atherosclerotic events. In order to test the hypothesis that decreasing the vascular level of iron slows lesion growth, we examined the effects of the iron chelator Desferal (72 mg/kg/day, 5 days/week) on atherosclerosis and lesion iron content in cholesterol-fed New Zealand White rabbits. Rabbits were fed with a 1% w/w cholesterol diet for either 8 weeks (and for the last 5 weeks injected daily with Desferal) or 12 weeks (and for the last 9 weeks injected with Desferal). Controls were injected with saline. A significant reduction in average lesion area (p = 0.038) was observed in the 12-week treated animals compared with the 12-week controls. The average lesion iron level of the 12-week treated animals (58 ppm dry wt) was also significantly lower (p = 0.030) than in 12-week control animals (95 ppm dry wt), as measured using nuclear microscopy with the combination of scanning transmission ion microscopy, Rutherford back-scattering spectroscopy, and particle-induced X-ray emission. No reduction in lesion area or iron content was observed in the 8-week treated animals compared with controls, and no change in lesion zinc concentration was observed for either group. Our data strengthen the concept that iron contributes to the early stages of the development of atherosclerosis. 相似文献
992.
993.
Protease MCP-01 is similar to other cold-adapted enzymes in that it is a cold-adapted serine protease having high specific activity and low thermostability at low and moderate temperature. Its thermolability and self-autolysis has resulted in difficulties in its purification, preservation and research on its structure and function. The disaccharide trehalose is known to effectively stabilize proteins. Its prevention effect on the autolysis of cold-adapted protease MCP-01 was monitored by capillary electrophoresis. In the absence of trehalose, protease MCP-01 autolyzed rapidly at 35 degrees C. However, when trehalose was added, autolysis was remarkably prevented and the loss of activity reduced. MCP-01 may be a useful model for basic research on the interaction of protein and trehalose. 相似文献
994.
Qualitative and Quantitative PCR Methods for Event-specific Detection of Genetically Modified Cotton Mon1445 and Mon531 总被引:12,自引:0,他引:12
Based on the DNA sequences of the junctions between recombinant and cotton genomic DNA of the two genetically modified (GM)
cotton varieties, herbicide-tolerance Mon1445 and insect-resistant Mon531, event-specific primers and probes for qualitative
and quantitative PCR detection for both GM cotton varieties were designed, and corresponding detection methods were developed.
In qualitative PCR detection, the simplex and multiplex PCR detection systems were established and employed to identify Mon1445
and Mon531 from other GM cottons and crops. The limits of detection (LODs) of the simplex PCR were 0.05% for both Mon1445
and Mon531 using 100 ng DNA templates in one reaction, and the LOD of multiplex PCR analysis was 0.1%. For further quantitative
detection using TaqMan real-time PCR systems for Mon1445 and Mon531, one plasmid pMD-ECS, used as reference molecule was constructed,
which contained the quantitative amplified fragments of Mon1445, Mon531, and cotton endogenous reference gene. The limits
of quantification (LOQs) of Mon1445 and Mon531 event-specific PCR systems using plasmid pMD-ECS as reference molecule were
10 copies, and the quantification range was from 0.03 to 100% in 100 ng of the DNA template for one reaction. Thereafter,
five mixed cotton samples containing 0, 0.5, 0.9, 3 and 5% Mon1445 or Mon531 were quantified using established real-time PCR
systems to evaluate the accuracy and precision of the developed real-time PCR detection systems. The accuracy expressed as
bias varied from 1.33 to 8.89% for tested Mon1445 cotton samples, and from 2.67 to 6.80% for Mon531. The precision expressed
as relative standard deviations (RSD) were different from 1.13 to 30.00% for Mon1445 cotton, and from 1.27 to 24.68% for Mon531.
The range of RSD was similar to other laboratory results (25%). Concluded from above results, we believed that the established
event-specific qualitative and quantitative PCR systems for Mon1445 and Mon531 in this study are acceptable and suitable for
GM cotton identification and quantification. 相似文献
995.
Reddy RE Pan Y Johnson DD Chen YY Datwyler SA Hauptman MS Thottathil JK 《Bioorganic & medicinal chemistry》2005,13(10):3467-3473
An efficient method was developed for the preparation of polyanionic affinity agent (3), a key component in the measurement of glycated hemoglobin (GHb). Glycated hemoglobin is an important clinical marker for diagnosis of patients with diabetes and useful to monitor the management of disease. The affinity agent (3) was prepared based on coupling reaction between poly(acrylic acid) (1) and 3-aminophenylboronic acid (2) in water. The critical features of this polymeric affinity agent (3), such as size, boronic acid incorporation ratio and concentration, on the measurement of glycated hemoglobin were evaluated. It was found that the agent (3) prepared using poly(acrylic acid) (1) with 225 kDa molecular weight gave optimal GHb measurement. The performance test results demonstrated that the boronic acid incorporation ratio and concentration of affinity agent (3) play a critical role in the assay and determines the precision of glycated hemoglobin measurement. 相似文献
996.
Schisandrin B--a novel inhibitor of P-glycoprotein 总被引:6,自引:0,他引:6
Qiangrong P Wang T Lu Q Hu X 《Biochemical and biophysical research communications》2005,335(2):406-411
P-glycoprotein-mediated drug efflux is one of the major causes of the cancer multidrug resistance (MDR). Inhibition of P-glycoprotein could reverse cancer MDR. Here, we show that schisandrin B, a naturally occurring compound from Schisandra chinensis (Turcz.) Baill, bears strong potency to inhibit P-glycoprotein. Schisandrin B reversed the drug resistance of four MDR cell lines characterized with overexpression of P-glycoprotein and fully restored the intracellular drug accumulation by interacting with P-glycoprotein. Schisandrin B has a core structure of dibenzocyclooctadiene, representing a novel P-glycoprotein inhibitor. To our best knowledge, the role of schisandrin B to inhibit P-glycoprotein has not been reported. 相似文献
997.
998.
999.
Gustafsson MV Zheng X Pereira T Gradin K Jin S Lundkvist J Ruas JL Poellinger L Lendahl U Bondesson M 《Developmental cell》2005,9(5):617-628
In addition to controlling a switch to glycolytic metabolism and induction of erythropoiesis and angiogenesis, hypoxia promotes the undifferentiated cell state in various stem and precursor cell populations. Here, we show that the latter process requires Notch signaling. Hypoxia blocks neuronal and myogenic differentiation in a Notch-dependent manner. Hypoxia activates Notch-responsive promoters and increases expression of Notch direct downstream genes. The Notch intracellular domain interacts with HIF-1alpha, a global regulator of oxygen homeostasis, and HIF-1alpha is recruited to Notch-responsive promoters upon Notch activation under hypoxic conditions. Taken together, these data provide molecular insights into how reduced oxygen levels control the cellular differentiation status and demonstrate a role for Notch in this process. 相似文献
1000.
Protein expression profiling of the drosophila fragile X mutant brain reveals up-regulation of monoamine synthesis 总被引:3,自引:0,他引:3
Zhang YQ Friedman DB Wang Z Woodruff E Pan L O'donnell J Broadie K 《Molecular & cellular proteomics : MCP》2005,4(3):278-290
Fragile X syndrome is the most common form of inherited mental retardation, associated with both cognitive and behavioral anomalies. The disease is caused by silencing of the fragile X mental retardation 1 (fmr1) gene, which encodes the mRNA-binding, translational regulator FMRP. Previously we established a disease model through mutation of Drosophila fmr1 (dfmr1) and showed that loss of dFMRP causes defects in neuronal structure, function, and behavioral output similar to the human disease state. To uncover molecular targets of dFMRP in the brain, we use here a proteomic approach involving two-dimensional difference gel electrophoresis analyses followed by mass spectrometry identification of proteins with significantly altered expression in dfmr1 null mutants. We then focus on two misregulated enzymes, phenylalanine hydroxylase (Henna) and GTP cyclohydrolase (Punch), both of which mediate in concert the synthetic pathways of two key monoamine neuromodulators, dopamine and serotonin. Brain enzymatic assays show a nearly 2-fold elevation of Punch activity in dfmr1 null mutants. Consistently brain neurochemical assays show that both dopamine and serotonin are significantly increased in dfmr1 null mutants. At a cellular level, dfmr1 null mutant neurons display a highly significant elevation of the dense core vesicles that package these monoamine neuromodulators for secretion. Taken together, these data indicate that dFMRP normally down-regulates the monoamine pathway, which is consequently up-regulated in the mutant condition. Elevated brain levels of dopamine and serotonin provide a plausible mechanistic explanation for aspects of cognitive and behavioral deficits in human patients. 相似文献