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51.
无义介导的mRNA降解途径(nonsense-mediated mRNA decay,NMD)作为细胞内的一种重要的mRNA质量监控机制,可以降解含有提前终止密码子(premature termination codon,PTC)的异常转录本,从而避免截短蛋白质对细胞的毒害,但其详细的分子机制有待进一步阐释。蓝氏贾第虫(Giardia lamblia)作为一种寄生性单细胞原生动物,进化地位特殊,对其NMD途径的研究有利于阐明基因表达调控的分子和进化机制。本研究通过酵母双杂交及体外pull-down实验分析了贾第虫NMD途径因子上游移码蛋白1(Giardia lamblia up-frameshift 1,GlUPF1)、贾第虫RNA结合蛋白(Giardia lamblia HRP1, GlHRP1)、贾第虫核糖核酸外切酶(Giardia lamblia Ski7p,GlSki7p、Giardia lamblia XRN1,GlXRN1)之间的相互作用关系。结果表明,GlUPF1全长与GlHRP1、GlXRN1(1~500 aa)、GlSki7p间均可发生相互作用。而且GlUPF1的CH结构域和C端结构域分别与GlHRP1、GlXRN1(1~500 aa)、GlSki7p相互作用。说明GlUPF1在贾第虫NMD途径中作为招募平台,在无义mRNA识别和降解过程中发挥重要作用。为此,结合本实验室之前的研究结果,我们提出原生动物贾第虫的NMD途径:在提前终止密码子处SURF(SMG1-UPF1-eRF1-eRF3)复合物形成后,GlUPF1被磷脂酰肌醇3-激酶(suppressor with morphogenetic effect on genitalia 1,SMG1)磷酸化修饰, NMD途径激活,随后GlUPF1与HRP1相互作用,将转录本标记为NMD底物;GlUPF1进而招募下游贾第虫5′-3′核糖核酸降解酶GlXRN1、贾第虫3′-5′ 核糖核酸降解因子GlSki7p,最终降解靶标mRNA。 相似文献
52.
Mouse models of the laminopathies 总被引:3,自引:0,他引:3
The A and B type lamins are nuclear intermediate filament proteins that comprise the bulk of the nuclear lamina, a thin proteinaceous structure underlying the inner nuclear membrane. The A type lamins are encoded by the lamin A gene (LMNA). Mutations in this gene have been linked to at least nine diseases, including the progeroid diseases Hutchinson-Gilford progeria and atypical Werner's syndromes, striated muscle diseases including muscular dystrophies and dilated cardiomyopathies, lipodystrophies affecting adipose tissue deposition, diseases affecting skeletal development, and a peripheral neuropathy. To understand how different diseases arise from different mutations in the same gene, mouse lines carrying some of the same mutations found in the human diseases have been established. We, and others have generated mice with different mutations that result in progeria, muscular dystrophy, and dilated cardiomyopathy. To further our understanding of the functions of the lamins, we also created mice lacking lamin B1, as well as mice expressing only one of the A type lamins. These mouse lines are providing insights into the functions of the lamina and how changes to the lamina affect the mechanical integrity of the nucleus as well as signaling pathways that, when disrupted, may contribute to the disease. 相似文献
53.
Rabinovich ML Vasil'chenko LG Karapetyan KN Shumakovich GP Yershevich OP Ludwig R Haltrich D Hadar Y Kozlov YP Yaropolov AI 《Biotechnology journal》2007,2(5):546-558
Amorphous cellulose was used as a specific carrier for the deposition of self-assembled multienzyme complexes capable of catalyzing coupled reactions. Naturally glycosylated fungal cellobiohydrolases (CBHs) of glycosyl hydrolase families 6 and 7 were specifically deposited onto the cellulose surface through their family I cellulose-binding modules (CBM). Naturally glycosylated fungal laccase was then deposited onto the preformed glycoprotein layer pretreated by ConA, through the interaction of mannosyl moieties of fungal glycoproteins with the multivalent lectin. The formation of a cellulase-ConA-laccase composite was proven by direct and indirect determination of activity of immobilized laccase. In the absence of cellulases and ConA, no laccase deposition onto the cellulose surface was observed. Finally, basidiomycetous cellobiose dehydrogenase (CDH) was deposited onto the cellulose surface through the specific interaction of its FAD domain with cellulose. The obtained paste was applied onto the surface of a Clark-type oxygen electrode and covered with a dialysis membrane. In the presence of traces of catechol or dopamine as mediators, the obtained immobilized multienzyme composite was capable of the coupled oxidation of cellulose by dissolved oxygen, thus providing the basis for a sensitive assay of the mediator. Swollen amorphous cellulose plays three different roles in the obtained biosensor as: (i) a gelforming matrix that captures the analyte and its oxidized intermediate, (ii) a specific carrier for protein self-assembly, and (iii) a source of excess substrate for a pseudo-reagent-less assay with signal amplification. The detection limit of such a tri-enzyme biosensor is 50-100 nM dopamine. 相似文献
54.
55.
目的:为了研究特定频谱波引起的水中离子浓度的变化以及电导率与频谱波间相互作用的规律,用特定频谱波对理化特性略有不同的纯净水、自来水、海水进行影响,研究其电导率的变化。方法:采用一元线性回归分析的方法对数据散点进行拟和,用方差分析来评价其拟合效果,以期发现其中的规律。结果:经过频谱波的影响各种水的电导率都有明显的提高,并且随着处理次数的增加,纯净水的电导率呈阶越式方式增加;自来水呈对数形式增加;而海水则表现为变化幅度微小。结论:造成这个现象的原因可能是由于水分子吸收了频谱波的能量,分子的平均动能增大造成的。这一过程使化学平衡(H2O)n≒xH2O (H2O)n-x和H2O≒ H OH-均向分解的方向运动,水中带电离子的浓度提高,因此电导率发生变化。而电导率提高方式的差异,则是水样在理化特性上的差异导致的。 相似文献
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57.
Stepanova EV Koroleva OV Vasil'chenko LG Karapetian KN Landesman EO Iavmetdinov IS Kozlov IuP Rabinovich ML 《Prikladnaia biokhimiia i mikrobiologiia》2003,39(1):74-84
White rot fungi (Coriolus hirsutus, Coriolus zonatus, and Cerrena maxima from the collection of the Komarov Botanical Institute of the Russian Academy of Sciences) and filamentous fungi (Mycelia sterilia INBI 2-26 and Trichoderma reesei 6/16) were grown on oat straw-based liquid and solid media, as well as in a bench-scale reactor, either individually or as co-cultures. All fungi grew well on solid agar medium supplemented with powdered oat straw as the sole carbon source. Under these conditions, the mould Trichoderma reesei fully suppressed the growth of all basidiomycetes studied; conversely, Mycelia sterilia neither affected the development of any of the cultures, nor did it show any substantial susceptibility to suppression by their presence. Pure solid cultures of basidiomycetes, as well as the co-culture of Coriolus hirsutus and Cerrena maxima caused a notable bleaching of the oat straw during its consumption. When grown on the surface of oat straw-based liquid medium, the basidiomycetes consumed up to 40% polysaccharides without measurable lignin degradation (a concomitant process). Under these conditions, Mycelia sterilia decomposed no more than 25% lignin in 60 days, but this was observed only after polysaccharide exhaustion and biomass accumulation. In contrast, during solid state straw fermentation, white rot fungi consumed up to 75% cellulose and 55% lignin in 83 days (C. zonarus), whereas the corresponding consumption levels for co-cultures of Mycelia sterilia and Trichoderma reesei equaled 70 and 45%, respectively (total loss of dry weight ranged from 55 to 60%). Carbon dioxide-monitored solid-state fermentation of oat straw by the co-culture of filamentous fungi was successfully performed in an aerated bench-scale reactor. 相似文献
58.
The reconstruction of the mesenterium microcirculatory bed was performed intravitally in albino rats and cats after biomicrophotograms. The number, length and caliber of arterioles, pericapillary arteriolec, capillaries, postcapillary venules and venules of the mesenterium were measured. According to these data summary indices of the cross section, surface and volume of the vessels of various functional subdivisions of the microcirculatory bed were calculated. The blood volume entering the microcirculatory system of the albino rat's mesenterium is distributed in the vessels as follows: 8,4% -- arterioles, 10,2% -- pericapillary arterioles, 41,9% -- capillaries, 22,1% -- postcapillary venules and 17,4% -- venules. Similar correlations were found in the cat. The working surface of capillaries is 60--70% of the working surface of all the vessels of the mesenterial microcirculatory system. The evidence of the functional variability of the microcirculatory bed geometry depending on the tissue needs in blood supply is presented. 相似文献
59.
Lj-RGD1来源于日本七鳃鳗口腔腺,富含半胱氨酸并具有RGD(Arg-Gly-Asp)模体.为了验证Lj-RGD1是否具有抑制血小板聚集、抗血管新生等去整合素样典型功能,本文对七鳃鳗Lj-RGD1进行了克隆表达及活性测定.提取七鳃鳗口腔腺中总RNA进行RT-PCR扩增,获得Lj-RGD1的420 bp cDNA.对其进行克隆、表达及组氨酸亲和层析纯化后,获得分子量为169 kD的可溶性蛋白rLj-RGD1.活性测定结果显示,rLj-RGD1呈剂量依赖方式抑制ADP诱导的兔血小板聚集,IC50为123 μmol/L;血管新生抑制实验结果表明,rLj-RGD1能够诱导ECV304细胞凋亡,抑制ECV304细胞增殖和管状物形成,并呈剂量依赖性方式抑制鸡胚胎绒毛尿囊膜(chorioallantoic membrane,CAM)血管新生.由此可见,Lj-RGD1具有去整合素样生物活性,在血栓或血管异常新生类疾病治疗中具有应用前景. 相似文献
60.
DNA疫苗进入细胞后,除了转译成蛋白质抗原,通过MHC分子进行内源性或外源性抗原提呈外,近年来还发现可直接与相应的被称为核酸传感器分子,如TLR9、DAI、AIM2、STING、DDX41解旋酶和RNA聚合酶Ⅲ等结合,继而激活不同的免疫信号通路.基于DNA疫苗的传感器分子和信号通路研制免疫佐剂,可有效增强DNA疫苗的免疫原性. 相似文献