右归丸对大鼠膝骨关节炎的干预作用及其机制

目的:探讨右归丸对膝骨关节炎(KOA)模型鼠关节软骨组织骨诱导因子(OGN)、骨黏连蛋白(ON)和纤维蛋白原2(FBN2)的影响。方法:将大鼠随机分为假手术组,模型组,硫酸氨基葡萄糖组(硫酸氨基葡萄糖),右归丸(高、中、低剂量)组,每组10只。采用改良Hulth法制备大鼠KOA模型,假手术组和模型组给予等体积生理盐水灌胃,右归丸高、中、低剂量组分别灌胃给予右归丸4.8,2.4,1.2 g/kg,硫酸氨基葡萄糖组灌胃给予硫酸氨基葡萄糖0.17 g/kg,连续给药8周。干预结束24 h后取鼠膝关节软骨,采用HE染色法观察各组软骨的病理改变,并进行Mankin评分;免疫组化法检测各组关节软骨组织中OGN、ON和FBN2的表达; Western blot法检测各组关节软骨组中糖原合成酶激酶-3β(GSK-3β)的表达。结果:与假手术组比较,模型组大鼠软骨组织Makin评分显著升高,软骨组织FBN2蛋白表达水平上显著增加,OGN、ON和GSK-3β蛋白表达水平上的显著降低(P<0.01);模型组关节软骨边缘严重破坏,软骨细胞排列紊乱。与模型组比较,右归丸高剂量干预组大鼠软骨组织Makin评...     

The essential effector SCRE1 in Ustilaginoidea virens suppresses rice immunity via a small peptide region

The biotrophic fungal pathogen Ustilaginoidea virens causes rice false smut, a newly emerging plant disease that has become epidemic worldwide in recent years. The U. virens genome encodes many putative effector proteins that, based on the study of other pathosystems, could play an essential role in fungal virulence. However, few studies have been reported on virulence functions of individual U. virens effectors. Here, we report our identification and characterization of the secreted cysteine-rich protein SCRE1, which is an essential virulence effector in U. virens. When SCRE1 was heterologously expressed in Magnaporthe oryzae, the protein was secreted and translocated into plant cells during infection. SCRE1 suppresses the immunity-associated hypersensitive response in the nonhost plant Nicotiana benthamiana. Induced expression of SCRE1 in rice also inhibits pattern-triggered immunity and enhances disease susceptibility to rice bacterial and fungal pathogens. The immunosuppressive activity is localized to a small peptide region that contains an important ‘cysteine-proline-alanine-arginine-serine’ motif. Furthermore, the scre1 knockout mutant generated using the CRISPR/Cas9 system is attenuated in U. virens virulence to rice, which is greatly complemented by the full-length SCRE1 gene. Collectively, this study indicates that the effector SCRE1 is able to inhibit host immunity and is required for full virulence of U. virens.     

黄芪种子萌发及萌发后生长过程中黄酮类化合物合成的动态变化

在对膜荚黄芪和蒙古黄芪种子萌发和萌发后生长时期进行划分的基础上,研究了黄芪中3种主要黄酮类化合物芒柄花素、毛蕊异黄酮和毛蕊异黄酮苷在萌发和萌发后生长过程中含量的变化。为了弄清黄酮含量变化的机制,我们还对黄芪中黄酮生物合成途径酶的转录水平做了研究。结果表明,在种子萌发和萌发后生长阶段,两种黄芪中均出现了明显的黄酮类化合物累积增加的情况。通过检测黄酮类物质生物合成途径酶基因的转录表达水平,我们发现萌发阶段蒙古黄芪中黄酮类物质积累增加主要由上游途径酶基因的表达水平升高引起,而膜荚黄芪中则几乎涉及到所有途径酶。此外,我们还发现萌发后生长阶段中,两种黄芪中合成途径酶基因转录对黄酮类物质含量的调控则选择性地存在时间延迟效应。     

拟南芥过氧化物酶序列与功能的生物信息学分析

植物过氧化物酶(POD)属于多基因家族,不仅是植物体内清除活性氧自由基的重要酶类之一,而且参与多种生理生化过程,在维系植物生长发育过程中发挥重要的作用。采用生物信息学方法对拟南芥过氧化物酶家族的73个基因编码的蛋白质序列的结构和功能进行了分析,其中包含氨基酸的数量、等电点、跨膜结构域、信号肽、二级结构组成及磷酸化位点等,并用Mega4.0软件构建了去除信号肽前后的系统进化树,旨在了解其结构特征。对已经进行功能研究的成员进行结构分析,以此来揭示结构与功能之间的联系,为植物抵御氧化胁迫方面研究提供理论基础。     

6_m2细胞转化与肌醇磷脂代谢相关性研究

肌醇磷脂代谢与V-mos癌基因转化细胞的相关性,迄今为止未见报导。本文用6m2细胞(Moloney鼠类肉瘤病毒(含V-mos)温度敏感突变株(MoMuSVts110)转化的NRK细胞)为模型,探讨了肌醇磷脂代谢与细胞转化的相关性。在33℃ (转化型温度)时,细胞内PIP(磷脂酰肌醇-4-磷酸)含量明显高于39℃(正常型温度),显示出转化型6m2细胞中存在一个提高的PI激酶活性。同时可见DG(二酰甘油)和IP_3(肌醇三磷酸)含量和蛋白激酶C(PKC)活性均明显高于正常型细胞。当细胞由39℃转至33℃10min,PIP、DG、IP_3含量和PKC活性均明显增加,并伴随有PKC活性由胞质向质膜上的转移。实验结果表明肌醇磷脂代谢参与了6m2细胞转化过程。文中对其作用机理进行了讨论。     

Expression vectors for human-mouse chimeric antibodies

The production of recombinant antibodies has been generally recognized as time-consuming and labor-intensive. The aim of our study is to construct mammalian expression vectors containing the cDNA encoding the human constant regions and murine variable regions to massively and cost-effectively produce full-length chimeric antibodies. Unique restriction sites flanking the Ig variable region were designed to allow for the replacement of variable regions generated by PCR. Western blot analysis of the chimeric antibodies revealed that the expressed products were of the predicted size, structure and specificity. The usefulness of the vectors was confirmed by construction of human-mouse chimeric antibody-HCAb which secretes murine antibody against the human colorectal cancer. Selected in medium containing gradually increasing methotrexate (MTX), clones with increased expression of the product gene can be efficiently generated. The secretion of recombinant chimeric antibody-HCAb yielded 30 pg cell(-1) day(-1) at 10(-6 )M MTX. With this high-level expression from pools, the convenient and rapid production of over 100 milligram amounts per liter of recombinant antibodies may be achieved, which indicates the significant roles of pYR-GCEVH and pYR-GCEVL in the production of chimeric antibodies.     

Avian influenza (H5N1) viruses isolated from humans in Asia in 2004 exhibit increased virulence in mammals

The spread of highly pathogenic avian influenza H5N1 viruses across Asia in 2003 and 2004 devastated domestic poultry populations and resulted in the largest and most lethal H5N1 virus outbreak in humans to date. To better understand the potential of H5N1 viruses isolated during this epizootic event to cause disease in mammals, we used the mouse and ferret models to evaluate the relative virulence of selected 2003 and 2004 H5N1 viruses representing multiple genetic and geographical groups and compared them to earlier H5N1 strains isolated from humans. Four of five human isolates tested were highly lethal for both mice and ferrets and exhibited a substantially greater level of virulence in ferrets than other H5N1 viruses isolated from humans since 1997. One human isolate and all four avian isolates tested were found to be of low virulence in either animal. The highly virulent viruses replicated to high titers in the mouse and ferret respiratory tracts and spread to multiple organs, including the brain. Rapid disease progression and high lethality rates in ferrets distinguished the highly virulent 2004 H5N1 viruses from the 1997 H5N1 viruses. A pair of viruses isolated from the same patient differed by eight amino acids, including a Lys/Glu disparity at 627 of PB2, previously identified as an H5N1 virulence factor in mice. The virus possessing Glu at 627 of PB2 exhibited only a modest decrease in virulence in mice and was highly virulent in ferrets, indicating that for this virus pair, the K627E PB2 difference did not have a prevailing effect on virulence in mice or ferrets. Our results demonstrate the general equivalence of mouse and ferret models for assessment of the virulence of 2003 and 2004 H5N1 viruses. However, the apparent enhancement of virulence of these viruses in humans in 2004 was better reflected in the ferret.     

Synthesis, crystal structure and magnetic properties of cubane and linear trinuclear nickel complexes formed by 3,5-dichloro-2-hydroxybenzylaminoacetic acid

The reaction of Ni(ClO₄)₂·6H₂O with 3,5-dichloro-2-hydroxy-benzylaminoacetic acid (H₂dchaa), NaN₃ and triethylamine in methanol solution or water solution under solvothermal methods leads to the formation of two completely different Ni^II compounds: [HN(C₂H₅)₃]₈·[Ni₄(dchaa)₄(N₃)₄]₂ (1) and [HN(C₂H₅)₃]₂·[Ni₃(dchaa)₄(H₂O)₄]₂·(H₂O)₂ (2). The complexes 1 and 2 have been characterized by elemental analyses, IR spectra and single-crystal X-ray diffraction. Structure analyses reveal that complex 1 is a cubane cluster, while the complex 2 is a linear trinuclear cluster. The magnetic investigation shows that complexes 1 and 2 exhibit a ferromagnetic coupling between Ni^II ions. Ac susceptibilities of 1 and 2 reveal no frequency-dependent out-of-phase signals and the corresponding magnetic properties were discussed.     

H<Subscript>2</Subscript> inhibits TNF-α-induced lectin-like oxidized LDL receptor-1 expression by inhibiting nuclear factor κB activation in endothelial cells

H₂ is a therapeutic antioxidant that can reduce oxidative stress. Oxidized low-density lipoprotein, which plays roles in atherosclerosis, may promote endothelial dysfunction by binding the cell-surface receptor LOX-1. LOX-1 expression can be upregulated by various stimuli, including TNF-α. Thus, we aimed to examine whether the upregulation of LOX-1 by different stimuli could be blocked by H₂ in endothelial cells. H₂ significantly abolished the upregulation of LOX-1 by different stimuli, including TNF-α, at the protein and mRNA levels. The TNF-α-induced upregulation of LOX-1 was also attenuated by the NF-κB inhibitor N-acetyl-l-cysteine. H₂ inhibited the TNF-α-induced activation of NF-κB and the phosphorylation of IκB-α. Furthermore, H₂ inhibited the expression of LOX-1 and the activation of NF-κB in apolipoprotein E knockout mice, an animal model of atherosclerosis. Thus, H₂ probably inhibits cytokine-induced LOX-1 gene expression by suppressing NF-κB activation.