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71.
Shixiang Wang Kun Zhao Weijin Zang Qian Zhang Xinfeng Zhao Ming Zhao Xi He Qinshe Liu Weiyi Feng Xiaohui Zheng 《Analytical biochemistry》2014
A highly selective assay was developed for screening compounds that bind to the porcine recombinant β2-adrenoceptor (β2-AR) with affinity chromatography coupled to quadrupole time-of-flight mass spectrometry (Q-TOF–MS). The methodology involved selective screening with immobilized β2-AR, a highly accurate identification via Q-TOF–MS, and a functional evaluation of the screened compounds with a sensitive myograph system. Ferulic acid, hydroxysafflor yellow A (HSYA), and naringin were confirmed to be the bioactive compounds in Huoxue capsule that specifically bound to the β2-AR. These compounds produced a concentration-dependent relaxation of arteries that were contracted by treatment with phenylephrine, and the relaxation caused by these compounds was attenuated in the presence of ICI 118551, a type of β2-AR antagonist. Our data indicate that the use of an immobilized receptor is potentially an alternative method for the rapid screening of bioactive compounds in a complex matrix because of its high specificity. β2-AR affinity chromatography was valuable in focusing attention on the further investigation of ferulic acid, HSYA, and naringin as β2-AR agonists. 相似文献
72.
Xinghui Lu Runguo Zang Yi Ding Susan G. Letcher Wenxing Long Yunfeng Huang 《Biotropica》2014,46(4):404-414
The seedling stage is generally the most important bottleneck for the successful regeneration of trees in forests. The traits of seedlings, particularly biomass allocation and root traits, are more easily quantified than the traits of adults. In this study, we tested the hypothesis that seedling traits vary and trade‐off tracking the changing environment during secondary succession. We measured the major morphological traits of 27 dominant species and the major environmental factors in a chronosequence (30‐yr‐old fallow, 60‐yr‐old fallow, and old growth forest) after shifting cultivation in a tropical lowland rain forest on Hainan Island, China. The 30‐yr‐old fallow had higher light and nutrient availability, and the older forests had higher soil water content. Redundancy analysis based on species abundance and environmental factors revealed groups of seedlings that dominate in different stages of succession. Seedlings in different stages of succession had different strategies of biomass allocation for harvesting resources that varied in availability. Species characteristic of younger forest had higher allocation to roots and higher specific leaf area, while species characteristic of older forest had higher allocation to leaves. Our study suggests that the variations and trade‐offs in the major functional traits of tree seedlings among successional classes may reflect changes in environmental conditions during succession. 相似文献
73.
Kyung-Jun Song Zang Geun Kim Chang Ik Zhang Yeong Hoon Kim 《Marine Mammal Science》2010,26(2):282-295
Entanglement of marine mammals in fishing gear is a global issue. It is considered a significant threat to minke whales (Balaenoptera acutorostrata) in the East Sea of Korea. A total of 214 entanglements of minke whales in this area between 2004 and 2007 were used to investigate types and parts of fishing gears involved in entanglements. The majority of entanglements were mainly caused by three types of fishing gears: set nets, pots, and gill nets (n= 207, 96.7%). Other entanglements were associated with bottom trawls, purse seines, and trawls. A total of 65 entanglements were attributed to the main and branch lines of fishing gears. The most common body part of minke whales which attached to fishing gears was the mouth (n= 63, 30.4%). Most entanglements took place within 10 nmi from land (n= 179, 86.5%), and between 10 and 220 m of water depth. The mean length of entangled minke whales in set nets was significantly smaller than that of whales in pots and gill nets samples (P < 0.001). Also, the mean body length of minke whales that entangled in the coastal area and shallow waters was significantly shorter than that of whales in the offshore area and deep waters (P < 0.001). This information can be used as fundamental data to conserve and manage this population of minke whales in the East Sea of Korea, and also to modify fishing gear to reduce entanglements. Future studies should focus on investigating the impact of these entanglements on the population and the effectiveness of mitigation measures to reduce entanglements of minke whales in this area. 相似文献
74.
cAMP-response-element-binding protein (CREB) signaling has been reported to be associated with cancer development and poor clinical outcome in various types of cancer. However, it remains to be elucidated whether CREB is involved in breast cancer development and osteotropism. Here, we found that metastatic MDA-MB-231 breast cancer cells exhibited higher CREB expression than did non-metastatic MCF-7 cells and that CREB expression was further increased by several soluble factors linked to cancer progression, such as IL-1, IGF-1, and TGF-β. Using wild-type CREB and a dominant-negative form (K-CREB), we found that CREB signaling positively regulated the proliferation, migration, and invasion of MDA-MB-231 cells. In addition, K-CREB prevented MDA-MB-231 cell-induced osteolytic lesions in a mouse model of cancer metastasis. Furthermore, CREB signaling in cancer cells regulated the gene expression of PTHrP, MMPs, and OPG, which are closely involved in cancer metastasis and bone destruction. These results indicate that breast cancer cells acquire CREB overexpression during their development and that this CREB upregulation plays an important role in multiple steps of breast cancer bone metastasis. 相似文献
75.
Sun P Zhang X Zang X Zhou X Chen Y Arunakumara KK Liang B 《Biotechnology letters》2007,29(7):1013-1018
Oral delivery of salmon calcitonin (sCT) to rats via a recombinant Saccharomyces cerevisiae was assessed. A synthetic sCT gene was cloned and expressed in S. cerevisiae yAGA2-sCT. Recombinant salmon calcitonin (rsCT) expression was detected by flow cytometry. The resorption activity of osteoclasts
was inhibited by 3 × 10−6 M rsCT. Oral administration of 5 g lyophilized yAGA2-sCT/kg to hypercalcemic rats decreased serum calcium from 2.8 ± 0.02–2.7 ± 0.02 mM. 相似文献
76.
腺苷和乙酰胆碱后适应诱导的心肌保护作用 总被引:3,自引:0,他引:3
近年来缺血后适应的提出成为抗再灌注损伤的里程碑,其良好的临床可控性和可靠的保护效应引起人们广泛关注。缺血后适应即在心肌长时间缺血后再灌注之前,进行数次短暂的再灌注,缺血的循环处理,诱导产生心肌保护效应,其循环次数和间隔时间存在种属差异。研究证实后适应不仅限制急性期梗死面积,还可以减轻长期损伤,其是否与保护血管内皮、抑制中性粒细胞介导的氧化损伤相关还存在争议。上调再灌注损伤补救激酶(reperfusion injury salvageHnase,RISK)通路是后适应保护的重要机制之一,即激活磷脂酰肌醇一3激酶(phosphatidy linositol3-kinase,P13K)-Akt途径和,或细胞外信号调节激酶(extracellular signal-regulatedkinase,ERK)途径,抑制线粒体通透性转换孔的开放,减少细胞凋亡和坏死。但是这两条途径的地位和关系还有待于进一步研究。为了更加适用于临床,研究者将机械调控转变为药物干预,观察药物能否模拟缺血后适应发挥保护作用,即药物后适应。腺苷是研究最广泛,也是最有希望成为临床正式用药的一种药物。我们实验室首先提出了乙酰胆碱可以模拟缺血后适应,通过线粒体ATP敏感钾通道发挥心肌保护效应。本文着重阐述缺血后适应保护缺血,再灌注损伤的效应和信号转导通路,尤其是腺苷和乙酰胆碱模拟药物后适应的可能机制和临床应用。 相似文献
77.
Wang J Zhang Z Hu Y Hou X Cui Q Zang Y Wang C 《Physiological research / Academia Scientiarum Bohemoslovaca》2007,56(1):17-23
Given the potential clinical benefit of inhibiting Na+/Ca2+ exchanger (NCX) activity during myocardial ischemia reperfusion (I/R), pharmacological approaches have been pursued to both inhibit and clarify the importance of this exchanger. SEA0400 was reported to have a potent NCX selectivity. Thus, we examined the effect of SEA0400 on NCX currents and I/R induced intracellular Ca2+ overload in mouse ventricular myocytes using patch clamp techniques and fluorescence measurements. Ischemia significantly inhibited inward and outward NCX current (from -0.04+/-0.01 nA to 0 nA at -100 mV; from 0.23+/-0.08 nA to 0.11+/-0.03 nA at +50 mV, n=7), Subsequent reperfusion not only restored the current rapidly but enhanced the current amplitude obviously, especially the outward currents (from 0.23+/-0.08 nA to 0.49+/-0.12 nA at +50 mV, n=7). [Ca2+]i, expressed as the ratio of Fura-2 fluorescence intensity, increased to 138+/-7% (P<0.01) during ischemia and to 210+/-11% (P<0.01) after reperfusion. The change of NCX current and the increase of [Ca2+]i during I/R can be blocked by SEA0400 in a dose-dependent manner with an EC50 value of 31 nM and 28 nM for the inward and outward NCX current, respectively. The results suggested that SEA0400 is a potent NCX inhibitor, which can protect mouse cardiac myocytes from Ca2+ overload during I/R injuries. 相似文献
78.
Zang N Tang DJ Wei ML He YQ Chen B Feng JX Xu J Gan YQ Jiang BL Tang JL 《Molecular plant-microbe interactions : MPMI》2007,20(1):21-30
Macrophage infectivity potentiators (Mips) are FKBP domain-containing proteins reported as virulence factors in several human pathogens, such as members of genera Legionella, Salmonella and Chlamydia. The putative peptidylprolyl cis-trans isomerase (PPIase) encoded by XC2699 of the plant bacterial pathogen Xanthomonas campestris pv. campestris 8004 exhibits a 49% similarity at the amino-acid level to the Mip protein of Legionella pneumophila. This mip-like gene, XC2699, was overexpressed in Escherichia coli and the purified (His)6-tagged Mip-like protein encoded by XC2699 exhibited a PPIase activity specifically inhibited by FK-506. A mutation in the mip-like gene XC2699 led to significant reductions in virulence and replication capacity in the host plant Chinese radish (Raphanus sativus L. var. radiculus Pers.). Furthermore, the production of exopolysaccharide and the activity of extracellular proteases, virulence factors of X. campestris pv. campestris, were significantly decreased in the mip-like mutant. These results reveal that the mip-like gene is involved in the pathogenesis of X. campestris pv. campestris through an effect on the production of these virulence factors. 相似文献
79.
In this paper, a kind of Typhaceae plant species, Typha angustifolia L, with a high tolerance to Cr is described. Experiments were carried out to examine its ability to tolerant Cr and its physiological response. The results showed that there was no difference in growth, plant height, and biomass response to external Cr (VI) between the plants exposed to 100 microM Cr (VI) and control (0 microM), while increasing Cr levels to 200-800 microM induced a significant decrease in plant height and biomass, but no significant injury was detected, even for the plants exposed to 800 microM Cr. Chromium induced significant increases in superoxide dismutase (SOD) and peroxidase (POD) activities. Meanwhile, a significantly positive correlation was found between Cr and Mn or Cu in leaves and roots, respectively. The Cr tolerance of the plant appeared to be associated with the enhancement of SOD and POD activities and the improvement in uptake and translocation of the essential microelements. 相似文献
80.
Notch signaling is essential for ventricular chamber development 总被引:1,自引:0,他引:1
Grego-Bessa J Luna-Zurita L del Monte G Bolós V Melgar P Arandilla A Garratt AN Zang H Mukouyama YS Chen H Shou W Ballestar E Esteller M Rojas A Pérez-Pomares JM de la Pompa JL 《Developmental cell》2007,12(3):415-429
Ventricular chamber morphogenesis, first manifested by trabeculae formation, is crucial for cardiac function and embryonic viability and depends on cellular interactions between the endocardium and myocardium. We show that ventricular Notch1 activity is highest at presumptive trabecular endocardium. RBPJk and Notch1 mutants show impaired trabeculation and marker expression, attenuated EphrinB2, NRG1, and BMP10 expression and signaling, and decreased myocardial proliferation. Functional and molecular analyses show that Notch inhibition prevents EphrinB2 expression, and that EphrinB2 is a direct Notch target acting upstream of NRG1 in the ventricles. However, BMP10 levels are found to be independent of both EphrinB2 and NRG1 during trabeculation. Accordingly, exogenous BMP10 rescues the myocardial proliferative defect of in vitro-cultured RBPJk mutants, while exogenous NRG1 rescues differentiation in parallel. We suggest that during trabeculation Notch independently regulates cardiomyocyte proliferation and differentiation, two exquisitely balanced processes whose perturbation may result in congenital heart disease. 相似文献