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71.
Lifang Guo Xingchao Geng Li Liu Yufa Miao Zhi Lin Min Yu Yan Fu Lihong Liu Bo Li Yongzhang Luo 《Journal of biochemical and molecular toxicology》2019,33(3)
Endostar, a potent endogenous antiangiogenic factor, is wildly used in clinics. However, it was easily degraded by enzymes and rapidly cleared by the kidneys. To overcome these shortcomings, PEGylated recombinant human endostatin was developed. In this study, the purity of M2ES was evaluated by silver stain and reversed‐phase high‐performance liquid chromatography. Ultraviolet spectrum was used to examine the structural of M2ES and endostar. The bioactivity and antitumor efficacy of M2ES were evaluated using an in vitro endothelial cell migration model and athymic nude mouse xenograft model of a heterogeneous lung adenocarcinoma, respectively. A preclinical study was performed to evaluate the acute toxicity and safety pharmacology in rhesus monkeys. The purity of M2ES was more than 98%; PEG modification has no effect on endostatin structure. Compared with the control group, M2ES dramatically retards endothelial cell migration and tumor growth. After intravenous (IV) infusions of M2ES at a dose level of three and 75 mg/kg in rhesus monkeys, there was no observable serious adverse event in both acute toxicity and safety pharmacology study. On the basis of the quality and bioactivity study data of M2ES and the absence of serious side effect in rhesus monkeys, M2ES was authorized to initiate a phase I clinical trial. 相似文献
72.
73.
Junna Wang Chong Li Xinbin Duan Daqing Chen Shunxin Feng Huihuang Luo Qidong Peng Wengen Liao 《Freshwater Biology》2014,59(7):1343-1360
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74.
Modulation of mouse neural crest cell motility by N-cadherin and connexin 43 gap junctions. 下载免费PDF全文
X Xu W E Li G Y Huang R Meyer T Chen Y Luo M P Thomas G L Radice C W Lo 《The Journal of cell biology》2001,154(1):217-230
Connexin 43 (Cx43alpha1) gap junction has been shown to have an essential role in mediating functional coupling of neural crest cells and in modulating neural crest cell migration. Here, we showed that N-cadherin and wnt1 are required for efficient dye coupling but not for the expression of Cx43alpha1 gap junctions in neural crest cells. Cell motility was found to be altered in the N-cadherin-deficient neural crest cells, but the alterations were different from that elicited by Cx43alpha1 deficiency. In contrast, wnt1-deficient neural crest cells showed no discernible change in cell motility. These observations suggest that dye coupling may not be a good measure of gap junction communication relevant to motility. Alternatively, Cx43alpha1 may serve a novel function in motility. We observed that p120 catenin (p120ctn), an Armadillo protein known to modulate cell motility, is colocalized not only with N-cadherin but also with Cx43alpha1. Moreover, the subcellular distribution of p120ctn was altered with N-cadherin or Cx43alpha1 deficiency. Based on these findings, we propose a model in which Cx43alpha1 and N-cadherin may modulate neural crest cell motility by engaging in a dynamic cross-talk with the cell's locomotory apparatus through p120ctn signaling. 相似文献
75.
山姜属(Alpinia L.)植物的花柱具卷曲运动的能力,该属植物的野生种群有两种表型的个体,其花柱运动方向相反。该文通过观察马来良姜(Alpinia mutica Roxb.)花柱的显微和超微结构来研究花柱卷曲运动的结构基础。结果表明两种表型的花柱解剖结构相同。花柱仅形态学上端区域(约占花柱总长度的25%)有卷曲运动能力,其它区域不能运动。运动区近轴侧分布着几层直径较大、形状不规则、相对较短且细胞壁较薄的细胞,远轴侧的细胞直径较小、狭长;非运动区近轴和远轴侧的细胞都呈狭长形。花柱运动区域近轴侧和远轴侧细胞结构和细胞层数的不对称可能是导致花柱卷曲运动的结构原因。 相似文献
76.
目的:探讨迷走神经复合体(Dorsal vagal complex,DVC)内orexin-A对顺铂所致胃功能紊乱的影响及可能机制。方法:随机选取30只大鼠并将其分为3组(n=10):对照组(NS组);24 h顺铂治疗组;48 h顺铂治疗组。24 h顺铂治疗组和48 h顺铂治疗组大鼠分别在腹腔注射顺铂后24 h和48 h处死大鼠,对照组大鼠腹腔注射生理盐水(Normal saline,NS)。采用定量实时PCR检测各组大鼠下丘脑orexin-A mRNA的表达,ELISA测量大鼠脑脊液中P物质水平;DVC内微量注射orexin-A和ghrelin受体拮抗剂后,检测大鼠食物和高岭土的摄入量。结果:顺铂可显著减少大鼠下丘脑orexin-A mRNA表达,增加其脑脊液内P物质的浓度。外源性orexin-A可改善顺铂引起的厌食症和异食癖。orexin-A以上的效应可被DVC内预先注射ghrelin受体拮抗剂部分逆转。结论:orexin-A可能通过ghrelin神经肽系统改善顺铂在化疗过程中诱导的胃功能紊乱。 相似文献
77.
Jinshan Yang Xiang Luo Xiaojiang Huang Qin Ning Minjie Xie Wei Wang 《Journal of neurochemistry》2014,131(3):383-394
Increasing evidence indicates that the Eph receptors and their ephrin ligands are involved in the regulation of interactions between neurons and astrocytes. Moreover, astrocytic ephrin‐A3 reverse signaling mediated by EphA4 receptors is necessary for controlling the abundance of glial glutamate transporters. However, the role of ephrin‐A3 reverse signaling in astrocytic function and neuronal death under ischemic conditions remains unclear. In the present study, we found that the EphA4 receptor and its ephrin‐A3 ligand, which were distributed in neurons and astrocytes, respectively, in the hippocampus showed a coincident up‐regulation of protein expression in the early stage of ischemia. Application of clustered EphA4 decreased the expressions of astrocytic glutamate transporters together with astrocytic glutamate uptake capacity through activating ephrin‐A3 reverse signaling. In consequence, neuronal loss was aggravated in the CA1 region of the hippocampus accompanied by impaired hippocampus‐dependent spatial memory when clustered EphA4 treatment was administered prior to transient global ischemia. These findings indicate that EphA4‐mediated ephrin‐A3 reverse signaling is a crucial mechanism for astrocytes to control glial glutamate transporters and prevent glutamate excitotoxicity under pathological conditions.
78.
甘肃矿产资源丰富,矿区酸性矿坑水(acid mine drainage,AMD)及周边土壤中嗜酸微生物种类丰富,具有相当大的研究价值.本研究通过Illumina高通量测序方法,对甘肃省4个矿区AMD及周边土壤中的细菌群落组成、相似性及功能组成进行分析.结果 表明,煤矿样品GNM细菌物种组成最为丰富,金矿样品LNJ1与紫金矿样品LNZJK细菌组成最相似,与属于铜矿的BYT物种较相近,与LNJ1同地区的LNJ2样品细菌组成相比较远.所有样品细菌主要分为放线菌门(Actinobacteria)、拟杆菌门(Bacteriodetes)、厚壁菌门(Firmicutes)和变形菌门(Proteobacteria)四大门,其中变形菌门(Proteobacteria)丰度最高.放线菌门(Actinobacteria)中不动杆菌属(Acinetobacter)、类诺卡氏属(Nocardioides)和芽球菌属(Blastococcus)表现出较高丰度;厚壁菌门(Firmicutes)中微小杆菌属(Exiguobacterium)和芽孢杆菌属(Bacillus)表现出较高丰度,且微小杆菌属(Exiguobacterium)丰度极高.通过功能预测发现,与煤矿样品GNM相比,LNJ1、LNJ2、BYT和LNZJK4个金属矿区样品中的微生物具有较强的氨基酸与碳源的转运与代谢、转录等功能以及较低的能量生产与转运、无机离子转运与代谢能力.通过探究AMD中的细菌多样性及其与重金属之间的相互关系,了解AMD采样区微生物群落结构,以期挖掘出更为丰富的具有重金属抗性的菌株资源,以应用于生物浸矿和环境修复等领域. 相似文献
79.
贺兰山马鹿冬春季生境的选择 总被引:4,自引:2,他引:4
2007年12月~2008年1月和2008年4~5月,在贺兰山利用痕迹检验法和直接观察法对马鹿阿拉善亚种冬春季生境选择进行研究.通过在选定的15条沟段里进行调查,冬春季各测定了131个和181个样方的18种生态因子.结果表明,冬春季贺兰山马鹿在植被类型、优势乔木、灌木密度、灌木高度、灌木距离、坡向、坡位、海拔高度、距裸岩距离和隐蔽级10种生态因子上差异极显著(P < 0.001),其余生态因子无显著差异(P < 0.05),相对于冬季生境而言,马鹿春季更偏爱选择以油松和青海云杉为优势乔木的山地针叶林带,灌木密度大、高度高、距离近,半阴半阳坡的中坡位,海拔较高,距裸岩较近,隐蔽程度高的生境.典则判别系数显示冬春季马鹿在生境选择上存在一定程度的重叠,但春季马鹿的分布范围要比冬季更广一些,Wilk's λ值显示冬春季马鹿的生境选择具有较高的差异性(Wilk's λ = 0.683,x2 = 116.995,df = 13,P < 0.001).逐步判别分析表明在区分冬春季马鹿生境方面有一系列生态因子发挥作用,依照贡献值的大小依次为:乔木密度、灌木距离、坡度、海拔高度、距水源距离、距裸岩距离和隐蔽级,由这7个变量构成的方程对冬春季马鹿生境的正确区分率达到79.9%,其中对春季的误判率为22.1%,对冬季的误判率为20.6%. 相似文献
80.
Zhang K Zang TZ Yang W Sun Y Mu Y Liu JQ Shen JC Luo GM 《The Journal of biological chemistry》2006,281(18):12516-12520
Substrate binding and the subsequent reaction are the two principal phenomena that underlie the activity of enzymes, and many enzyme-like catalysts were generated based on the phenomena. The single chain variable region fragment of antibody 2F3 (scFv2F3) was elicited against hapten GSH-S-DN2phBu, a conjugate of glutathione (GSH), butyl alcohol, and 1-chloro-2,4-dinitrobenzene (CDNB); it can therefore bind both GSH and CDNB, the substrates of native glutathione S-transferases (GSTs). It was shown previously that there is a serine residue that is the catalytic group of GST in the CDR regions of scFv2F3 close to the sulfhydryl of GSH. Thus, we anticipated that scFv2F3 will display GST activity. The experimental results showed that scFv2F3 indeed displayed GST activity that is equivalent to the rat-class GST T-2-2 and exhibited pH- and temperature-dependent catalytic activity. Steady-state kinetic studies showed that the Km values for the substrates are close to those of native GSTs, indicating that scFv2F3 has strong affinities for the substrates. Compared with some other GSTs, its kcat value was found to be low, which could be caused by the similarity between the GSH-S-DN2phBu and the reaction product of GSH and CDNB. These results showed that our approach to imitating enzymes is correct, which is that an active site may catalyze a chemical reaction when a catalytic group locates beside a substrate-binding site of a receptor. It is important to consider product inhibition in hapten design in order to obtain a mimic with a high catalytic efficiency. 相似文献