复合季铵盐消毒剂含量的测定与滴定误差分析

研究复合季铵盐消毒剂含量的测定与滴定误差分析。探讨了四苯硼钠标准液配制及对滴定分析终点颜色的影响,并与单季铵盐定量分析方法进行了对比。结果表明:四苯硼钠两相滴定法适合于复合季铵盐定量分析,但要注意四苯硼钠标准液配制的正确性及滴定终点颜色的判断。     

NaCl胁迫对玉米幼苗不同器官离子含量的影响

在实验室水培条件下,研究了NaCl胁迫下玉米幼苗不同器官中Na+、K+,Ca2+,Mg 2+和Cl-含量的变化.结果表明:玉米各个部分Na+和Cl-含量、Na+/K+和Na+/Ca2+比值均随着培养液中NaCl浓度的增加而迅速提高,Na+,K+和Cl-含量的变化幅度为根系>成熟叶叶鞘>生长叶>成熟叶叶片,玉米幼苗根系最易受外界离子浓度的影响,叶片受外界环境影响较小;各器官中Ca2+、Mg2+对盐胁迫的响应不一致,NaCl胁迫使根系中Ca2+、Mg2+含量下降,成熟叶叶鞘中Mg2+含量变化规律性不明显,而NaCl胁迫下,成熟叶叶片中Ca2+、Mg2+含量增加;玉米幼苗具有拒Na+机制,具有一定的耐盐性,它的耐盐性是通过根和成熟叶叶鞘来实现的,Na+主要贮存在根系和成熟叶叶鞘中,而向成熟叶叶片和生长叶中运输较少;成熟叶叶鞘同时还具有拒Cl-能力.     

High-level expression of soluble subunit b of F1F0 ATP synthase in Escherichia coli cell-free system

The overexpression of subunit b of F₁F₀ adenosine triphosphate (ATP) synthase from Escherichia coli is so toxic that it even prevents the transformation of plasmids encoding this protein into E. coli BL21 (DE3). In the present work, E. coli cell-free system was chosen as an alternative to express this highly toxic membrane protein. This protein was either produced as precipitates followed by detergent resolubilization or expressed as a soluble form with detergent addition. Among several types of tested detergents, Brij 58 could effectively solubilize approximately 85% of the target membrane protein within a wide range of concentration (48 to 178 times critical micelle concentration [CMC]) with little effect on the expression level. With the presence of Brij 58 at the final concentration of 96 times CMC in the E. coli cell-free system, 789 μg/mL of soluble subunit b was achieved after 4 h biosynthesis, which is the highest level for the expression of membrane proteins in a batch-mode cell-free expression system. The present work provides a rapid and efficient procedure of expressing one membrane protein with high cytotoxicity in the cell-free system and will be helpful to further exploration of reconstituting F₁F₀ ATP synthase into liposome or polymer vesicle to design a nanoelectromechanical system device.     

kitl非编码区突变导致RNA剪切异常的小鼠

本文主要采用RT-RCR技术从kitl1-bao纯合子和正常C57BL/6(B6)小鼠总RNA中扩增出kitl基因片段,测序后与GenBank(登录号:NM.013598)序列比对,找到mRNA上突变部位。PCR扩增kitl基因组DNA上对应部位进一步测序验证。结果发现kitl1-bao突变纯合子kitl基因mRNA缺少第8号外显子。在基因组DNA上kitl基因第8号内含子第2个碱基由T转换为C,是引起mRNA剪接错误的原因     

细胞因子基因转导对人乳腺癌细胞MHC抗原及细胞膜糖蛋白表达的影响

为探讨细胞因子基因(人IL-2、IL-6)转导对于肿瘤细胞膜MHC抗原及细胞膜糖蛋白表达调控的影响,本文利用脂质体介导的方法,将含人IL-6、IL-2基因的逆转录病毒载体分别导入人乳腺癌细胞系MCF-7细胞中,采用间接免疫荧光染色流式细胞仪测定法,对基因转导的瘤细胞细胞膜糖蛋白及MHC抗原表达进行测定。结果表明经两种基因修饰的MCF-7细胞MHCⅠ型抗原表达均获得增强,此外,基因转导细胞可程度不同地表现出细胞膜多种糖蛋白表达的变化。提示肿瘤细胞膜抗原及糖蛋白表达的改变可能是细胞因子基因转导影响肿瘤细胞免疫原性的重要结构基础。     

瘦素对小鼠脑缺血/再灌注损伤神经元凋亡的影响

目的：研究Leptin在脑缺血性损伤神经元凋亡中的作用及其机制。方法：将75只雄性昆明小鼠完全随机分成3组,即假手术组、缺血/再灌注模型组、Leptin干预组;通过大脑中动脉栓塞（MCAO）复制小鼠局灶性脑缺血再灌注损伤模型,Leptin干预组在缺血0 min腹腔注射Leptin（1μg/g体重）,TUNEL染色检测神经元凋亡,RT-PCR检测凋亡相关基因bcl-2和caspase-3 mRNA表达,免疫组化凋亡相关基因bcl-2和caspase-3蛋白水平的表达。结果：模型组脑缺血中心区神经元以坏死为主,与假手术组相比,其半影区神经元凋亡数量显著增多、促凋亡基因cas-pase-3和抑凋亡基因bcl-2的mRNA和蛋白表达水平均显著升高（P<0.01）;与模型组比较,Leptin干预组半影区凋亡神经元数量显著减少、caspase-3 mRNA和蛋白表达水平显著降低（P<0.01）,抑凋亡基因bcl-2 mRNA和蛋白表达水平显著升高（P<0.01）。结论：Leptin能够通过上调抑凋亡基因bcl-2表达,下调促凋亡基因caspase-3表达抑制神经元凋亡,在脑缺血性损伤中发挥神经保护作用。     

水稻条纹病毒RNA4基因间隔区的分子变异

应用反转录－聚合酶链式反应（RT－PCR）和单链构象多态性（single-strand conformation polymorphism,SSCP)技术快速检测我国水稻条纹病毒（RSV）RNA4基因间隔区（intergenic region,IR)的分子变异,结果表明,我国RSV RNA4 IR存在分子变异。供试的7个分离物共有4种泳动带型,其中YL、BS、JD、LY分离物完全一致,而YL、BS、YL及JD4个分离物序列完全一致;JN、PJ、SQ3个分离各不一样,序列之间的同源性均在92％－94％之间.IR序列内部具有两个重要的结构特征：（1）有两处反向重复序列,可形成两个明显的发夹结构,其中一个序列比较保守,形成的发夹结构稳定;但中一个发夹结构由于碱基变异导致其稳定性在各个分离物中差异较大;（2）具有插入序列,相对于日本M分离物,我国7个分离物都有一段长19bp的插入序列,这段插入序列比较保守,各分离物之间仅有1－2个碱基的差异。     

Exosomes derived from umbilical cord mesenchymal stem cells alleviate viral myocarditis through activating AMPK/mTOR‐mediated autophagy flux pathway

Human umbilical cord mesenchymal stem cell‐derived exosomes (hucMSC‐exosomes) have been implicated as a novel therapeutic approach for tissue injury repair and regeneration, but the effects of hucMSC‐exosomes on coxsackievirus B3 (CVB3)‐induced myocarditis remain unknown. The object of the present study is to investigate whether hucMSC‐exosomes have therapeutic effects on CVB3‐induced myocarditis (VMC). HucMSC‐exosomes were identified using nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM) and Western blot. The purified hucMSC‐exosomes tagged with PKH26 were tail intravenously injected into VMC model mice in vivo and used to administrate CVB3‐infected human cardiomyocytes (HCMs) in vitro, respectively. The effects of hucMSC‐exosomes on myocardial pathology injury, proinflammatory cytokines and cardiac function were evaluated through haematoxylin and eosin (H&E) staining, quantitative polymerase chain reaction (qPCR) and Doppler echocardiography. The anti‐apoptosis role and potential mechanism of hucMSC‐exosomes were explored using TUNEL staining, flow cytometry, immunohistochemistry, Ad‐mRFP‐GFP‐LC3 transduction and Western blot. In vivo results showed that hucMSC‐exosomes (50 μg iv) significantly alleviated myocardium injury, shrank the production of proinflammatory cytokines and improved cardiac function. Moreover, in vitro data showed that hucMSC‐exosomes (50 μg/mL) inhibited the apoptosis of CVB3‐infected HCM through increasing pAMPK/AMPK ratio and up‐regulating autophagy proteins LC3II/I, BECLIN‐1 and anti‐apoptosis protein BCL‐2 as well as decreasing pmTOR/mTOR ratio, promoting the degradation of autophagy flux protein P62 and down‐regulating apoptosis protein BAX. In conclusion, hucMSC‐exosomes could alleviate CVB3‐induced myocarditis via activating AMPK/mTOR‐mediated autophagy flux pathway to attenuate cardiomyocyte apoptosis, which will be benefit for MSC‐exosome therapy of myocarditis in the future.     

枯草芽胞杆菌异戊二烯酶ComQ的生物信息学分析及对生物膜形态的影响

[目的]枯草芽胞杆菌ComQ是一种类异戊二烯生物合成酶.利用生物信息学预测分析了ComQ的生物学特性,对comQ基因进行过表达和敲除,构建突变菌,孔板发酵培养验证生物膜形态变化.[方法]运用NCBI (National Center for Biotechnology Information)网站里的Protein数据...     

青藏高原蝇科昆虫生物地理初探

对青藏高原蝇科昆虫进行了生物地理学研究.青藏高原已知蝇科9亚科42属574种,以特有类群占优势.其中特有属占11.9%,特有种占66.2%,文中讨论了该地区区系成分的多源性,特有成份的特异性及青藏高原北缘特有属的起源与演化,特有种的狭域分布现象及理论探讨.讨论了该地区与其它地区间隔分布的多样性及高原蝇科昆虫的适应性.分析了青藏高原的隆起与冰期对蝇科昆虫的作用.青藏高原的横空崛起以及第四纪冰期--间冰期的循环往复,导致该地区生境千差万别,使蝇科区系不仅有地域分异,且垂直差异显著.在此期间,北方物种向南入侵,南北成分交互渗透,高山类群适应进化,使许多特有成分在这里被陶冶、孕育,故而造成了该地区蝇科区系的特有性和物种的多样性.