乌司他丁对大鼠脑缺血再灌注损伤后的保护作用及其机制研究

目的:探究乌司他丁在脑缺血再灌注损伤中的脑保护作用机制。方法:原代分离培养雄性SD大鼠脑皮质细胞,部分细胞经siRNA沉默HSP70基因。细胞先以无糖培养基在低氧条件下培养,12 h后复糖复氧模拟体外缺血再灌注损伤,并实施乌司他丁预处理干预,流式细胞术检测各组细胞的凋亡率,western-blotting检测Bcl-2,Bax,HSP70,JNK和p-JNK蛋白的表达。结果:与对照组比较,模型组脑组织细胞凋亡率明显增多(P0.05)、Bcl-2和Bax的表达量均有上调,Bcl-2/Bax的比值显著降低(P0.01)、HSP70的表达无显著变化;与模型组比较,乌司他丁处理组脑组织细胞凋亡率明显降低(P0.05)、Bax的表达量显著下调(P0.05),Bcl-2/Bax的比值显著上调(P0.05),HSP70的表达显著上调(P0.05),JNK的表达无显著变化、p-JNK则显著下调(P0.05)。HSP70沉默后乌司他丁的脑保护作用消失,对以上蛋白的表达无显著影响。结论:乌司他丁可能是通过上调HSP70表达进而抑制JNK信号转导通路对缺血再灌注引起的脑损伤起保护作用。     

高糖腹透液通过神经酰胺经JNK/SAPK通路介导腹膜间皮细胞凋亡

目的观察葡萄糖腹膜透析液(peritoneal dialysis solution,PDS)对人腹膜间皮细胞(peritoneal mesothelium cells,PMCs)凋亡的影响,探讨神经酰胺在高糖PDS诱导的PMCs凋亡中的作用机制。方法 PMCs分别在正常对照、1.5%PDS、4.25%PDS条件下培养,以4.25%甘露醇作为高渗对照。高压液相串联质谱法(LC/MS/MS)检测细胞内神经酰胺的变化,TUNEL检测细胞凋亡,Western blot检测p-JNK、p-c-Jun、Bax、Bcl-2蛋白水平。结果 PDS呈浓度、时间依赖性上调PMCs细胞内神经酰胺,正常对照组、高渗对照组细胞内神经酰胺无明显变化;相比1.5%PDS组,4.25%PDS可诱导PMCs细胞凋亡,促进JNK及其下游c-Jun磷酸化,而酸性鞘磷脂酶抑制剂地昔帕明可显著抑制高糖PDS的此类作用;JNK阻断剂SP600125可明显抑制高糖PDS诱导的JNK和c-Jun活化、进而抑制Bax的上调和Bcl-2的下调。结论细胞内神经酰胺增加可能经JNK/SAPK通路参与高糖PDS诱导的PMCs凋亡。     

细胞色素c的释放是多巴胺诱导PC12细胞凋亡的重要环节

通过末端脱氧核苷酸转移酶介导dUTP缺口翻译法和DNA凝胶电泳观察多巴胺(DA)对PC12细胞凋亡的诱导作用, 并经蛋白质印迹法检测胞浆细胞色素c、Bcl-2和Bax蛋白以及活化型半胱氨酸蛋白酶3(caspase-3)水平. 结果表明, 在DA诱导PC12细胞凋亡的过程中, 可见PC12细胞中活化型caspase-3蛋白表达, 胞浆中细胞色素c水平明显增高, 同时Bcl-2蛋白水平下降, 而Bax蛋白水平明显增加. 环孢菌素A预处理对细胞色素c释放和caspase-3激活有明显的抑制作用, 而对Bcl-2和Bax蛋白影响不明显. 结果提示, Bcl-2和Bax蛋白、细胞色素c以及caspase-3可能参与DA诱导PC12细胞凋亡, 线粒体细胞色素c向胞浆释放可能是其中的中心环节.     

姜黄素通过MAPK信号通路诱导人肝癌SMMC-7721细胞凋亡

本文阐述了姜黄素(Curcumin)对体外培养的人肝癌SMMC-7721细胞增殖和凋亡的影响,并探讨了其诱导凋亡的信号转导机制。采用MTT法和细胞计数法检测不同浓度姜黄素对人肝癌细胞株SMMC-7721增殖的影响,利用流式细胞术检测姜黄素对人肝癌SMMC-7721细胞凋亡的影响,通过RT-PCR及Western blot检测姜黄素对人肝癌SMMC-7721细胞中凋亡相关蛋白Caspase-3、Survivin、Bcl-2和Bax表达的影响,最后通过检测MAPK的磷酸化水平分析姜黄素诱导SMMC-7721细胞凋亡的信号转导机制,通过MAPK抑制剂实验进一步证实诱导凋亡的分子机制。研究结果显示,姜黄素呈时间和剂量依赖性抑制人肝癌SMMC-7721细胞的增殖,其中40μmol/L姜黄素可明显诱导SMMC-7721细胞的凋亡,并呈时间依赖性上调促凋亡蛋白Caspase-3和Bax的表达、下调抗凋亡蛋白Survivin和Bcl-2的表达,姜黄素对凋亡相关蛋白表达的调节及诱导凋亡可以通过激活JNK、抑制ERK和p38 MAPK信号通路实现。表明姜黄素可诱导人肝癌SMMC-7721细胞凋亡,其机制与姜黄素激活JNK、抑制ERK和p38 MAPK信号通路从而上调Caspase-3和Bax的表达,下调Survivin和Bcl-2的表达有关。     

抗氧化肽SS-31抑制高糖诱导的心肌细胞凋亡

该文探讨了抗氧化肽SS-31对高糖诱导的大鼠心肌细胞凋亡的影响,体外培养大鼠心肌细胞(H9C2),给予高糖(30 mmol/L)进行刺激,并利用抗氧化肽SS-31进行治疗后,采用Western blot检测Bax、Bcl-2、Cleaved caspase-3、Nox1、Nox4和Txnip的表达;利用荧光实时定量PCR(Real-time PCR)检测Bax、Bcl-2、Nox1、Nox4和Txnip mRNA的表达;采用原位缺口末端标记法(TUNEL)观察H9C2细胞凋亡情况;应用MitoSOX~(TM )Red染色检测H9C2细胞线粒体ROS产生情况。结果显示,与正常对照组相比,高糖组H9C2细胞凋亡明显增加,Bax、 Cleaved caspase-3、Nox1、Nox4和Txnip蛋白表达明显上调,Bcl-2蛋白表达减少,线粒体ROS产生增加;SS-31治疗后能够抑制高糖诱导的H9C2细胞的凋亡,下调Bax、Cleaved caspase-3、Nox1、Nox4、Txnip表达,上调Bcl-2表达并减少线粒体ROS的产生。以上研究结果提示,抗氧化肽SS-31抑制高糖诱导的大鼠心肌细胞凋亡的同时抑制Txnip/ROS产生,表明抗氧化肽SS-31可能对糖尿病心肌病变具有一定的改善作用。     

前列腺癌干细胞拮抗剂盐霉素对人前列腺癌PC3细胞增殖和凋亡的影响

为了探讨前列腺癌干细胞拮抗剂盐霉素对人前列腺癌PC3细胞增值、凋亡和迁移的影响,本研究用前列腺癌干细胞拮抗剂盐霉素处理人前列腺癌PC3细胞,用CCK-8检测细胞的增殖能力,用流式细胞术检测细胞的凋亡状况,蛋白免疫印迹技术检测凋亡蛋白Bax和Bcl-2,划痕实验检测细胞迁移。用前列腺癌干细胞拮抗剂盐霉素处理人前列腺PC3细胞后,其细胞增殖能力显著下降,凋亡细胞显著增加,促凋亡蛋白Bax的表达明显增加,抗凋亡蛋白Bcl-2的表达显著降低,且细胞划痕修复率显著降低。前列腺癌干细胞拮抗剂盐霉素可诱导人前列腺癌PC3细胞活力降低、凋亡增多和迁移抑制。     

芜菁中性多糖对PC12细胞氧化损伤保护作用机制的初步研究CSCD

以H_(2)O_(2)诱导PC12细胞建立氧化损伤模型,研究芜菁中性多糖(neutral polysaccharide from Brassica rapa L.,BRNP)对PC12细胞氧化损伤保护及初步作用机制。采用CCK-8法检测细胞存活率;乳酸脱氢酶(LDH)检测H_(2)O_(2)对PC12细胞氧化损伤的保护作用;JC-1法检测BRNP对H_(2)O_(2)诱导的PC12细胞线粒体膜电位的影响;Western blot法检测BRNP对H_(2)O_(2)诱导的PC12细胞Bax、Bcl-2和Caspase-3蛋白表达水平。结果表明,BRNP对PC12细胞无明显细胞毒性;H_(2)O_(2)的造模浓度和时间分别为300μmol/L、4 h;BRNP在一定程度上可减轻H_(2)O_(2)对PC12细胞的氧化损伤;BRNP可降低H_(2)O_(2)对PC12细胞线粒体膜电位的损伤;以不同剂量BRNP干预PC12细胞后,Bax、Caspase-3蛋白表达水平均有显著降低(P<0.05);而Bcl-2蛋白表达水平显著升高(P<0.05)。综上所述,BRNP能够改善H_(2)O_(2)诱导的PC12细胞氧化应激损伤及保护其细胞功能,其作用机制可能与抑制细胞内LDH生成、提高抗氧化酶活性及其凋亡蛋白表达水平有关。     

藏花素对H_2O_2诱导PC12细胞Bcl-2、Bax和Caspase-3的影响

本文通过观察藏花素对H2O2诱导的PC12细胞的保护作用和对Bcl-2、Bax和Caspase-3的影响,探讨藏花素对阿尔茨海默病细胞模型保护作用的机制。MTT法及LDH活性测定观察藏花素对PC12细胞模型的影响,RT-PCR检测Bcl-2、Bax和Caspase-3 mRNA表达水平,Western blot检测Bcl-2、Bax和Caspase-3的蛋白表达。藏花素预保护浓度在0.625μM和5μM之间,细胞存活率随着藏花素浓度的升高而升高;藏花素组和VE组与模型组相比,Bcl-2 mRNA和蛋白表达增加(P0.05),Bax和Caspase-3 mRNA和蛋白表达降低(P0.05)。研究结果表明:藏花素可能是通过上调Bcl-2的表达,从而介导PC12细胞发挥抗氧化和细胞凋亡的生物学功能。     

硫酸化茯苓多糖对人乳腺癌细胞株MCF-7凋亡的影响

为了探讨硫酸化茯苓多糖(SP)对人乳腺癌细胞株MCF-7凋亡的影响,采用MTT法检测不同浓度、作用时间SP对乳腺癌MCF-7细胞的抑制作用,倒置显微镜观察MCF-7细胞的形态学变化,RT-PCR检测SP处理MCF-7细胞凋亡相关基因(Bcl-2,Bax)的表达;Western blotting技术检测SP对乳腺癌细胞凋亡蛋白Bcl-2、Bax表达变化。结果表明,SP对MCF-7细胞增殖有抑制作用,且在一定范围内呈剂量效应;细胞贴壁能力减弱,细胞间隙增大,胞膜褶皱;Bcl-2基因表达水平和蛋白表达水平明显降低(p0.05),Bax基因表达水平和蛋白表达水平明显升高(p0.05)。基于以上研究,SP通过促凋亡基因Bax的表达,抑制抗凋亡基因Bcl-2的表达来下调Bcl-2/Bax比值,激活凋亡途径,诱导MCF-7细胞的凋亡。     

桃叶珊瑚苷对光损伤HaCaT细胞Bax, Bcl-2, Caspase-3表达的影响

目的:探讨桃叶珊瑚苷对紫外线B诱导的HaCaT细胞凋亡相关蛋白Bax、Bcl-2、Caspase-3表达的影响,进一步阐明桃叶珊瑚苷抗光老化的作用机制。方法:将指数生长期HaCaT细胞随机分为正常对照组、模型对照组、10~(-7)、10~(-6)、10~(-5) mol·L~(-1) AU处理组,采用64 m J·cm~(-2)的UVB照射建立细胞光损伤模型,以终浓度10~(-7)、10~(-6)、10~(-5)mol·L~(-1)AU处理光损伤细胞,试剂盒检测ROS含量、Caspase-3活性,流式细胞术检测细胞凋亡率,Western-Blot检测Bcl-2、Bax蛋白的表达量。结果:UV照射的HaCaT细胞ROS含量、细胞凋亡率、Caspase-3活性、Bcl-2、Bax蛋白表达量均升高(P0.01),Bcl-2/Bax值降低(P0.01);不同浓度桃叶珊瑚苷处理后,ROS含量、Caspase-3活性、Bax蛋白表达量降低,Bcl-2蛋白表达量、Bcl-2/Bax值升高,10~(-6)、10~(-5) mol·L~(-1)桃叶珊瑚苷组与模型对照组相比,差异具有统计学意义(P0.05,0.01)。结论:桃叶珊瑚苷通过清除ROS,下调Bax、Caspase-3表达,上调Bcl-2表达,抑制细胞凋亡,保护受损的HaCaT细胞,拮抗光老化。     

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     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

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.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细