肠道病毒A71型亚单位蛋白对RD细胞自噬活化的影响

肠道病毒A71型（Enterovirus-A71, EV-A71）能够活化宿主细胞的自噬并依赖自噬促进其复制,然而EV-A71的亚单位蛋白对自噬的活化目前仍不清楚。为探讨EV-A71亚单位蛋白对人横纹肌肉瘤（Human rhabdomyosarcoma, RD）细胞自噬活化的影响,将EV-A71的亚单位蛋白重组真核质粒转染至RD细胞,采用抑制剂MK-2206阻断PI3K/Akt途径,共聚焦显微镜和免疫印迹检测自噬活化。过表达EV-A71亚单位蛋白的RD细胞中PI3K/Akt途径、p38、JNK和ERK途径均呈现不同程度活化,同时RD细胞呈现出绿色荧光表明自噬发生活化,特别是EV-A71的VP2和2A。EV-A71亚单位蛋白使LC3-II/LC3-I的转化水平提升,EV-A71亚单位蛋白（VP2、VP3、VP4、2A、2B和2C）显著提升p62的表达水平,EV-A71 VP1显著下调p62的表达水平但显著上调LAMP-1和LAMP-2的表达水平。阻断PI3K/Akt途径后,过表达EV-A71亚单位蛋白的RD细胞绿色荧光强度显著减弱、自噬被阻断,同时LC3-II/LC3-I的转化水平显著降...     

HCMV感染对胶质瘤细胞U87自噬的影响

研究人巨细胞病毒(HCMV)感染对神经胶质瘤U87细胞自噬的影响。通过观察微管相关蛋白1轻链3(LC3)、自噬相关基因Beclin1及其蛋白表达的变化,从而探讨HCMV与神经胶质瘤发生、发展的关系及意义。用HCMV AD169(MOI=5)感染神经胶质瘤U87细胞,同时将未感染HCMV的U87细胞作为对照组。分别在6、12、24、48 h用RT-PCR检测Beclin1的表达,Western-blot和免疫荧光检测Beclin1和LC3编码蛋白的表达,最后用CCK-8检测细胞的增殖活性。结果显示,HCMV感染的U87细胞LC3-II蛋白表达水平逐渐下降(P<0.05);同时,HCMV感染的U87细胞Beclin1基因及蛋白的表达水平也逐渐下降(P<0.01),且HCMV感染U87细胞增殖显著(P<0.01)。以上结果表明,HCMV感染抑制胶质瘤U87细胞自噬,并会引起Beclin1表达水平下调,进而导致胶质瘤细胞增殖。     

miRNA-383对急性胰腺炎腺泡细胞自噬的影响作用

目的:检测转染mi RNA-383的急性胰腺炎细胞模型中自噬标志蛋白LC3及Beclin1的表达情况,研究mi RNA-383对急性胰腺炎腺泡细胞自噬功能的影响作用。方法:在前期工作中利用生物信息技术筛选出在急性胰腺炎中表达下调的mi RNA-383。培养AR42J细胞,转染mi RNA-383类似物、抑制物以及阴性对照。使用牛磺胆酸钠盐以浓度200μM刺激细胞20 min制造急性胰腺炎细胞模型,使用BZi PAR检测胰酶激活程度证明此造模方法成功后,以此条件在转染完成后刺激AR42J细胞制造急性胰腺炎细胞模型。牛磺胆酸钠盐以浓度200μM刺激细胞20 min后提取细胞蛋白,利用western blot技术检测各组自噬标志蛋白Beclin1的表达情况及LC3-Ⅱ与LC3-Ⅰ比值的变化。结果:急性胰腺炎细胞模型造模成功,western blot技术检测mi RNA-383抑制物转染组AR42J细胞自噬标志蛋白Beclin1表达水平及LC3-Ⅱ/LC3-Ⅰ的值上调(P0.05),mi RNA-383类似物转染组细胞Beclin1表达水平及LC3-Ⅱ/LC3-Ⅰ的值下调(P0.05)。结论:mi RNA-383可以降低急性胰腺炎时细胞自噬水平,下调mi RNA-383的表达可以提高急性胰腺炎时细胞自噬水平。     

结核分枝杆菌eis基因对鼠巨噬细胞Raw264．7白噬影响的研究

目的探讨结核分枝杆菌eis基因对巨噬细胞自噬的影响。方法将鼠巨噬细胞Raw264．7以自噬体荧光表达质粒GFP-LC3转染,将含eis基因的重组耻垢分枝杆菌MS—pmv261-eis与不含eis基因的耻垢分枝杆菌MS—pmv261分别感染宿主巨噬细胞,透射电镜下观察自噬小体形成情况,荧光显微镜下观察自噬荧光并计数,Westernblot检测如基因表达的蛋白及自噬蛋白LC3-Ⅱ的表达水平。结果结核分枝杆菌eis基因可抑制感染宿主细胞自噬小体的形成,并显著抑制自噬荧光小点形成（P〈0．05）,显著降低了自噬蛋白LC3-Ⅱ表达水平。结论结核分枝杆菌e曲基因对Raw264．7细胞自噬有抑制作用。     

塞内卡病毒A结构蛋白VP2诱导PK-15细胞自噬的研究

本研究在塞内卡病毒A(Senecavirus A,SVA)诱导自噬的基础上,着重探究VP2蛋白在细胞自噬过程中的作用。构建VP2基因真核表达载体pcDNA3.1-VP2,将其转染至PK-15细胞,通过检测自噬蛋白和相关基因的表达情况,明确VP2蛋白对细胞自噬的影响。结果显示,本研究成功构建了pcDNA3.1-VP2真核表达载体,且SVA VP2基因在PK-15细胞中正常表达;与对照组相比,VP2蛋白显著上调LC3蛋白的表达水平（P<0.01）;同时,自噬基因LC3、Beclin-1和ATG5转录水平均显著提高（P<0.01）。综上所述,本研究证实SVA VP2蛋白可诱导PK-15细胞自噬,且VP2蛋白与自噬蛋白和基因表达水平呈正相关,为进一步研究病毒感染与致病机制打下基础。     

维生素D对烟曲霉感染的肺巨噬细胞 自噬机制的初步研究

目的探究维生素D在鼠肺细胞感染烟曲霉后对细胞自噬的影响。方法用一定量的烟曲霉活化孢子感染细胞后,一组细胞加入维生素D(维生素D组),一组细胞加入生理盐水,感染一定时间后用溶酶体探针检测自噬相关分子的表达;收集各组细胞并裂解细胞,离心取上清,用Western-blot法检测上清液中的LC3BII、Dectin-1及ROS的表达水平。结果活化的孢子感染肺巨噬细胞后,维生素D组自噬体与溶酶体共定位减少、吞噬孢子的速率在减少以及ROS水平降低,其对应的胞内Dectin-1、ROS、LC3BII减少且差异有统计学意义。结论烟曲霉感染肺巨噬细胞后,维生素D可通过减弱细胞自噬体与溶酶体的融合并下调自噬信号通路蛋白的表达以达到抵抗烟曲霉感染的作用。     

二氢生物喋呤还原酶参与调控HEK293T细胞自噬作用的初步研究

目的探讨二氢生物喋呤还原酶（dihydropteridine reductase,QDPR）对HEK293T细胞自噬作用的影响。方法构建野生型QDPR和突变型QDPR重组质粒分别转染HEK293T细胞,并设空载体对照组。采用RT-PCR及Western blot方法检测空载体组,野生型QDPR组和突变型QDPR组自噬相关蛋白LC3和Beclin 1的表达量变化。结果 1）测序结果证实PCR扩增得到编码正常QDPR的cDNA序列正确以及突变的cDNA也在正确的位置突变;2）磷酸钙共沉淀法转染HEK293T细胞后,野生型QDPR和突变型QDPR融合蛋白成功表达;3）RT-PCR结果显示,与对照组相比,野生型QDPR组LC3基因水平明显上调（P〈0.05）,突变型QDPR组LC3基因水平与对照组相比无统计学差异;与对照组相比,野生型和突变型组Beclin1基因水平无统计学差异;4）Western blot结果显示,与对照组相比,野生型QDPR组LC3-II和Beclin1的蛋白表达量明显上调（P〈0.05）,但LC3-I的蛋白表达量无统计学差异,突变型QDPR组与对照组相比LC3-I,II和Beclin1的蛋白表达量均没有统计学差异（P〉0.05）。结论二氢生物喋呤还原酶能增强HEK293T细胞自噬相关基因LC3和Beclin 1的表达,提示其可能具有激活自噬作用的功能;二氢生物喋呤还原酶93位氨基酸的突变影响了其对细胞自噬作用的调控,降低了自噬标志分子LC3-I和Beclin1的基因表达。     

青藏高原黑果枸杞花青素对人肝癌细胞增殖和自噬的影响

探究黑果枸杞花青素在体外对人肝癌HepG2细胞增殖和自噬的影响。利用CCK-8法测定细胞活力,EdU和细胞划痕试验检测细胞增殖和迁移效果,RT-PCR和Western blot检测增殖和自噬相关基因的mRNA和蛋白表达。结果显示,黑果枸杞花青素可有效抑制人肝癌HepG2细胞的增殖和迁移;上调增殖因子(LATS1、LATS2和MOB1)和自噬因子(Beclin-1、LC3-Ⅱ和AMPK),并下调增殖因子YAP的mRNA水平;下调自噬因子p-mTOR和细胞周期因子CDK4,并上调自噬因子p-AMPK和LC3-Ⅱ的蛋白表达。由此推测黑果枸杞花青素可在体外抑制人肝癌HepG2细胞增殖和迁移,并促进人肝癌HepG2细胞发生自噬。     

小豆蔻明调控自噬抑制卵巢癌SKOV3细胞增殖的研究

目的：卵巢癌为女性常见病,死亡率高,分子靶向治疗药物较少,研发高效低毒的靶向新药意义重大。细胞自噬（autophagy）维持着细胞内稳态和生长,是抗癌药物作用的关键靶部位。本课题旨在明确小豆蔻明（Cardamonin,CAR）调控自噬对卵巢癌SKOV3细胞增殖的影响。方法：体外培养卵巢癌SKOV3细胞,不同药物分组处理,荧光显微镜下观察单黄酰戊二胺（MDC）染色后细胞自噬囊泡,WesternBlot法检测细胞自噬相关蛋白LC3的表达,四氮唑蓝（MTT）法观察SKOV3细胞增殖情况,流式细胞术检测SKOV3细胞凋亡的变化。结果：自噬抑制剂3-MA显著性降低SKOV3细胞内MDC染色的荧光颗粒数目、LC3II蛋白表达,抑制细胞增殖;而CAR（高、中剂量）、雷帕霉素和AZD8055与3-MA联用后细胞内MDC荧光颗粒数目增多、LC3II蛋白表达增加、细胞增殖抑制率及凋亡率明显升高;且高剂量CAR（10^-6mol·L^-1）的作用比低剂量CAR（10^-6mol·L^-1）明显。结论：CAR能够抑制SKOV3细胞增殖,诱导细胞自噬,促进细胞凋亡。CAR有望成为卵巢癌药物治疗的先导化合物。本研究为进一步研发此类化合物提供了实验依据及一定的理论基础。     

PC12细胞在缺氧条件下的自噬现象

目的：考察PC12细胞内自噬发生与缺氧时间的关系,探讨自噬对缺氧细胞的影响作用。方法：以PC12细胞为模型,将对数生长期的细胞加入96孔培养板,37℃、5% CO₂培养24 h后,放入0.5% O₂、94.5% N₂和5% CO₂的培养箱缺氧1 h、3 h、6 h、9h、12 h、24 h、36 h和48 h,用MTT法检测细胞存活率,透射电镜观察细胞内自噬体,Westen blot法检测自噬相关蛋白（LC3B、Atg5和Beclin1）的表达,用试剂盒检测细胞内乳酸脱氢酶（LDH）活性、活性氧自由基（ROS）和线粒体膜电位（MNP）水平,探究缺氧不同时间自噬对PC12细胞的作用。结果：在缺氧3~12 h,PC12细胞自噬明显增加,自噬相关蛋白（LC3B、Atg5和Beclin1）表达增加,尤其是缺氧9 h,PC12细胞存活明显增加,表明短时间缺氧自噬对细胞起保护作用,而随着缺氧时间的延长细胞存活明显降低,自噬相关蛋白表达水平减少,细胞LHD和ROS水平明显增加。MMP水平显著下降,细胞凋亡明显增加。结论：在缺氧早期自噬对PC12细胞起保护作用,但缺氧时间较长,超过了细胞自身调节能力导致细胞死亡。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV