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61.
MyD88是IL-1R/TLR受体超家族向细胞内转导胞外信号时募集到受体胞浆尾部的重要接头蛋白.由TIR结构域介导的MyD88分子同源二聚化是它招募到受体胞浆尾部的前提,然后二聚化的MyD88再募集下游信号分子,传递信号,引发促炎基因的表达.本研究旨在建立一种模型,以实现活细胞原位的、基于荧光信号变化的MyD88二聚化抑制物的高通量筛选.我们分别构建了MyD88 TIR与GFP和RFP的融合蛋白表达质粒,瞬时转染HeLa细胞,在488 nm激发光下,转染GFP-MyD88 TIR和RFP-MyD88 TIR细胞,检测到绿色荧光与红色荧光间的共振能量转移(FRET).而当细胞转染GFP-MyD88 TIR和RFP或RFP-MyD88 TIR和GFP,因TIR二聚化不能实现,FRET效率受到严重影响.实验结果提示,依赖双阳性表达GFP-MyD88 TIR和RFP-MyD88 TIR的细胞株,检测不同化合物对于荧光FRET效率的影响,可以建立MyD88 TIR二聚化抑制药物的筛选模型.此外,我们构建了原核表达质粒,利用纯化的His-MyD88 TIR分别与GST或GST-MyD88 TIR蛋白进行体外结合实验,发现GST-MyD88 TIR(而非GST)可以与His-MyD88 TIR相互结合.结果的差异性提示,利用His-MyD88 TIR和GST-MyD88 TIR体外结合实验分析,可以进一步确定抑制物是否直接阻断了TIR的相互作用.结合真核细胞的荧光FRET阻断结果和原核表达的重组蛋白相互作用分析,可确定MyD88 TIR二聚化的抑制物.利用这一模型可以对商品化的小分子库、自行制备的天然产物组分进行广泛的筛选,从中获得有效抑制MyD88二聚化的化合物,参与对MyD88信号通路依赖的慢性炎症、自身免疫性疾病的药物治疗.  相似文献   
62.
报道中国鳖甲族1新纪录属及1新种:异颚弗鳖甲Freudeia heteromaxillaria sp.nov.,描述了新种的形态特征并附鉴别特征图和整体照片.新种模式标本保存于中国科学院西北高原生物研究所和河北大学博物馆.  相似文献   
63.
报道中国鳖甲族1新纪录属及1新种:异颚弗鳖甲Freudeia heteromaxillaria sp.nov.,描述了新种的形态特征并附鉴别特征图和整体照片。新种模式标本保存于中国科学院西北高原生物研究所和河北大学博物馆。  相似文献   
64.
Running speed in animals depends on both genetic and environmental conditions. Maximal speeds were here analysed in horses, dogs and humans using data sets on the 10 best performers covering more than a century of races. This includes a variety of distances in humans (200–1500 m). Speed has been progressing fast in the three species, and this has been followed by a plateau. Based on a Gompertz model, the current best performances reach 97.4% of maximal velocity in greyhounds to 100.3 in humans. Further analysis based on a subset of individuals and using an ‘animal model’ shows that running speed is heritable in horses (h2 = 0.438, P = 0.01) and almost so in dogs (h2 = 0.183, P = 0.08), suggesting the involvement of genetic factors. Speed progression in humans is more likely due to an enlarged population of runners, associated with improved training practices. The analysis of a data subset (40 last years in 800 and 1500 m) further showed that East Africans have strikingly improved their speed, now reaching the upper part of the human distribution, whereas that of Nordic runners stagnated in the 800 m and even declined in the 1500 m. Although speed progression in dogs and horses on one side and humans on the other has not been affected by the same genetic/environmental balance of forces, it is likely that further progress will be extremely limited.  相似文献   
65.
The hepatitis B virus PRE contains a splicing regulatory element   总被引:2,自引:0,他引:2  
  相似文献   
66.
We studied 42 species of saprophagous, Neotropical Copestylum (Diptera, Syrphidae) reared from decaying Cactaceae and Agavaceae. Thirty‐three species were reared during fieldwork in Bolivia, Costa Rica, Ecuador, Mexico, Peru, and Trinidad from 1998–2007. Nine species came from museum and private collections. Seven were new species. We describe these new species and the third stage larva and/or puparium and breeding sites of 40 species. Not described are two apparent species related to Copestylum apicale (Loew, 1866) reared from Cactaceae. Resolution of their status was beyond the scope of this paper but reference is made to their distinctive larval morphology. Based on early stage characters all reared species can be placed in ten species groups, all but three of which have been recognized previously on the basis of adult characters. A high level of congruence was found between adult and larval characters in terms of these species groups. Eight of the groups appear to be related closely and may represent a monophyletic lineage within Copestylum that has diversified in xeric habitats. Early stage morphology varied within and amongst groups but two trends in functional morphology are recognizable. One trend is towards feeding in watery decay and the other towards feeding in firmer decay. The latter trend is characterized by species that scoop food and use grinding mills in their head skeletons to break it up. They also have armoured thoraces with varying arrangements of sclerotized spicules or stiffened setae for gripping and protection during tunnelling, a short anal segment, and a short posterior breathing tube for protecting the openings. The former trend is characterized by species with opposite and contrasting features. They filter food and have well‐developed pre‐oral setal filters but they lack grinding mills or only have poorly developed grinding mills. They have reduced thoracic armature, elongate anal segments, and posterior breathing tubes which facilitates simultaneous feeding and respiration. Comparison with 23 Copestylum species reared from bromeliads (Bromeliaceae) suggests a common pattern of diversification in that species groups with the largest body sizes are more specialized.  相似文献   
67.
Multiple types of regulation are used by cells and viruses to control alternative splicing. In murine leukemia virus, accessibility of the 5′ splice site (ss) is regulated by an upstream region, which can fold into a complex RNA stem–loop structure. The underlying sequence of the structure itself is negligible, since most of it could be functionally replaced by a simple heterologous RNA stem–loop preserving the wild-type splicing pattern. Increasing the RNA duplex formation between U1 snRNA and the 5′ss by a compensatory mutation in position +6 led to enhanced splicing. Interestingly, this mutation affects splicing only in the context of the secondary structure, arguing for a dynamic interplay between structure and primary 5′ss sequence. The reduced 5′ss accessibility could also be counteracted by recruiting a splicing enhancer domain via a modified MS2 phage coat protein to a single binding site at the tip of the simple RNA stem–loop. The mechanism of 5′ss attenuation was revealed using hyperstable U1 snRNA mutants, showing that restricted U1 snRNP access is the cause of retroviral alternative splicing.  相似文献   
68.
目的探讨应用BR-TRG-I型体腔热灌注治疗系统进行持续循环腹腔热灌注治疗(continuous circulatory hyperthermic intraperitoneal perfusion treatment,CCHIP)对实验动物的生命体征、肝肾功能及内脏器官病理形态的影响。方法选用家猪作为实验动物,应用BR-TRG-I型体腔热灌注治疗系统建立CCHIP动物模型,分别用44℃、45℃的设定温度进行CCHIP。在CCHIP期间记录实验动物的生命体征变化;CCHIP前及治疗后1d、3d、7d和14d抽取外周血液保存备检;CCHIP结束后即刻及2周后处死动物,观察内脏器官的大体形态学改变,切取肝、肾、小肠等器官进行病理检查。结果44℃CCHIP持续1.5h对猪的生命体征、肝肾功能无明显影响,肝、肾、小肠等脏器损伤较轻,2周后恢复正常;45℃CCHIP持续1.5h对猪的生命体征影响严重,肝肾功能损害持续2周尚不能恢复正常,肝、肾、小肠等脏器病理损伤明显。结论44℃温度CCHIP1.5h安全可行,可以作为CCHIP的安全温度;45℃温度CCHIP1.5h可对实验动物肝肾功能造成严重损害,不适合作为CCHIP的治疗温度。  相似文献   
69.
介绍了组合使用BLAST、FASTA/BLASTScan3.2,或用多序列比对软件,从数据库中快速提取大数量目标序列,最后用MEGA4快捷编辑整理大数量序列的方法。还介绍了一种生成核酸序列与其氨基酸序列相似性百分率整合表格的方法。简述了对引物设计的基本认识并介绍了多重引物兼容性筛选软件;对构建系统发育树的认识并引出分子进化树构建软件MEGA4的使用和PAUP 4.0常用建树命令模块。期望这些方法和软件的使用能解决生物序列分析过程的常见问题。  相似文献   
70.
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