华蟾素对MDA - MB -231细胞线粒体膜电位及活性氧的影响

目的:研究华蟾素诱导乳腺癌MDA - MB - 231细胞凋亡过程中,细胞内活性氧(ROS)及线粒体膜电位(△Ψm)的变化,探讨华蟾素对乳腺癌细胞的作用机制.方法:用不同浓度的华蟾素作用于MDA - MB - 231细胞24h后,分别用荧光探针罗丹明123和荧光探针DCFH-DA进行荧光染色,用流式细胞仪检测细胞内线粒体膜电位和活性氧的变化.结果:不同浓度的华蟾素作用于MDA - MB - 231细胞后,随着药物浓度的增加(0、12.5、25、37.5、50μg/ml),细胞内的ROS水平显著升高,荧光强度从3 609±24上升为6 263±35;同时,线粒体膜电位(△Ψm)显著下降,荧光强度从242±6降低到173±4.结论:华蟾素作用细胞后,使得细胞内活性氧水平显著升高,同时,线粒体膜电位显著下降,推测华蟾素对MDA - MB - 231细胞通过线粒体途径诱发细胞凋亡.     

运动神经元特异性荧光报告系统的建立

人类诱导多能干细胞 (Human induced pluripotent stem cells,hiPSCs) 具有向人体多种类型细胞分化的潜能,其定向分化的运动神经元 (Motor neurons,MNs) 是众多运动神经元疾病的重要体外模型之一。为简化MNs的鉴定方法,通过慢病毒载体将MNs特异性启动子HB9及其控制下的红色荧光蛋白 (Red fluorescent protein,RFP) 基因转入hiPSCs分化而来的神经干细胞 (Human neural stem cells,hNSCs),经抗生素筛选,获得稳定的阳性细胞株hNSCs-HB9-RFP-Puro。而后,阳性细胞株感染过表达MNs定向分化转录因子的慢病毒LV-Ngn2-Sox11-GFP和LV-Isl1-Lhx3-Hygro,诱导MNs定向分化。诱导分化所得的细胞展现出神经元样结构,并在特异性启动子HB9的作用下表达RFP;同时也表达神经元相关标记物β微管蛋白 (β-tubulin) 和乙酰胆碱转移酶 (Choline acetyltransferase,ChAT),鉴定为成熟的MNs。该荧光报告系统为MNs的定向分化及鉴定提供了一个更加直观的方法,有效促进了MNs在疾病模型和药物筛选等领域的广泛应用。     

白头翁汤正丁醇提取物诱导白念珠菌生物被膜细胞凋亡

目的探讨白头翁汤正丁醇提取物(Butyl alcohol extract of Bai Tou Weng decoction,BAEB)对白念珠菌生物被膜细胞凋亡的影响。方法分别以DCFH-DA染色和JC-1染色,用流式细胞仪检测白念珠菌生物被膜细胞内活性氧(ROS)水平和线粒体膜电位(MMP)变化;Annexin V-FITC/PI染色染色荧光显微镜观察白念珠菌生物被膜细胞磷脂酰丝氨酸(phosphatidylserine,PS)外翻并检测凋亡率;FITC-VAD-FMK染色观察白念珠菌生物被膜细胞metacaspase活性;DAPI染色观察白念珠菌生物被膜细胞核形态。结果≥128μg/mL BAEB处理后白念珠菌生物被膜细胞内活性氧水平显著升高,线粒体膜电位显著降低,PS外翻增加,凋亡率明显升高,metacaspase酶活性显著升高,细胞核出现固缩和碎裂。结论白头翁汤正丁醇提取物可诱导白念珠菌生物被膜细胞凋亡。     

紫檀茋诱导白念珠菌凋亡的研究

目的探究紫檀茋(Pterostilbene,PTE)诱导白念珠菌凋亡的活性。方法通过分析白念珠菌凋亡细胞、坏死细胞和活细胞比例,检测Caspase酶活性、细胞内活性氧和线粒体膜电位,评价PTE诱导白念珠菌凋亡的活性。结果≥4μg/mL PTE处理后白念珠菌凋亡比例明显增加,Caspase酶活性显著升高,细胞内活性氧水平显著升高,线粒体膜电位显著降低。结论 PTE具有诱导白念珠菌凋亡的活性,该作用可能与活性氧积累和线粒体损伤相关。     

达格列净对高渗诱导的血管内皮细胞衰老的干预研究

目的:探讨SGLT2i类药物达格列净(dapagliflozin)对高渗诱导的人脐静脉内皮细胞(HUVECs)衰老的影响。方法:将HUVECs分为空白组(Blank组)、高渗330组(M-330组)、高渗350组(M-350组)、达格列净+高渗组(DAPA+M-350组),高渗培养环境由甘露醇诱导。衰老相关β-半乳糖苷酶(SA-β-Gal)染色检测细胞衰老情况;免疫荧光染色检测SGLT2表达变化;Western blot检测SGLT2、细胞衰老标志物p21的表达变化,JC-1染色试剂盒检测线粒体膜电位的变化。结果:免疫荧光染色和western blot结果显示,Blank组,M-330组及M-350组细胞上均存在SGLT2受体蛋白表达,且Blank组,M-330组及M-350组的SGLT2表达依次显著增加。与Blank组相比,M-350组SA-β-Gal胞质蓝染、染色阳性率、衰老蛋白p21及SGLT2表达显著增加,并伴有线粒体膜电位的显著下降(P0.05);DAPA+M-350组与M-350组相比,SA-β-Gal胞质蓝染、染色阳性率和p21表达显著下降,并伴有线粒体膜电位的显著上升(P0.05)。结论:HUVECs上存在SGLT2受体蛋白,且在300-350 m Osm/L范围内随着渗透压的升高而增加,达格列净可改善高渗所诱导的血管内皮细胞衰老,其机制可能与达格列净改善高渗导致的线粒体功能障碍有关。     

中药臭灵丹中3, 5-二羟基-6, 7, 3′, 4′-四甲氧基黄酮对人鼻咽癌CNE细胞凋亡的影响及机制

中药臭灵丹中黄酮类化合物3,5-二羟基-6,7,3′,4′-四甲氧基黄酮(3,5-hydroxy-6,7,3′,4′-tetramethoxyflavone,HTMF)体外对多种肿瘤细胞有抑增殖作用,但机制尚未完全清楚.为探讨HTMF对人鼻咽癌CNE细胞凋亡的影响,用MTT法检测HTMF对CNE细胞株的增殖抑制率,倒置显微镜观察HTMF作用于CNE细胞后细胞形态变化,Hoechst 33258荧光染色观察细胞核形态的变化,流式细胞仪检测细胞的凋亡率,Western blot法检测凋亡蛋白Caspase3和Caspase9的变化,流式细胞仪检测线粒体跨膜电位(△准m)值的改变,并用JC-1荧光染料染色,激光共聚焦显微镜观察线粒体膜电位变化.结果显示,分离自臭灵丹的HTMF呈浓度、时间双重依赖性显著抑制CNE细胞的增殖,诱导细胞凋亡,引起线粒体膜电位下降及凋亡蛋白Caspase3和Caspase9的活化.提示:3,5-二羟基-6,7,3′,4′-四甲氧基黄酮对人鼻咽癌CNE细胞的生长有显著的抑制作用,并可通过降低线粒体膜电位激活Caspase9,进而活化Caspase3诱导CNE细胞凋亡.     

长裂苦苣菜水提取物对肺癌细胞A549增殖和凋亡的影响

为了探讨长裂苦苣菜水提取物对肺癌细胞A549的影响,本研究用不同浓度的长裂苦苣菜水提取物作用于体外培养的A549细胞,从细胞形态(显微镜观察)、细胞增殖活力(CCK-8法)、细胞凋亡(Annexin V-FITC/PI染色)、线粒体膜电位(JC-1染色)和细胞内活性氧水平(荧光探针DCFH-DA染色)几个方面检测长裂苦苣菜水提取物对体外培养的A549细胞的影响。当处理浓度达到1 mg/mL作用细胞48 h后,细胞出现明显皱缩的凋亡形态学特征,与对照组相比处理组细胞增殖活力明显下降(P0.05)。进一步用流式细胞仪检测发现≥1mg/mL的处理浓度作用细胞48 h后细胞凋亡率显著提高(P0.05),同时检测到处理组细胞的膜电位都明显下降,细胞内活性氧水平明显上升,都呈剂量依赖关系。这些结果表明长裂苦苣菜水提取物可以诱导A549细胞凋亡,并抑制其生长和增殖,是一种潜在的预防和抑制肿瘤生长的药食两用植物。     

小分子化合物诱导干细胞向视网膜感光细胞分化的研究进展

干细胞是一类具有多向分化潜能的细胞群,如胚胎干细胞(embryonic stem cell,ESC)、诱导多潜能干细胞(induced pluripotent stem cell,i PSC)等,可在特定的条件下向包括视网膜感光细胞在内的多种细胞分化。小分子化合物是一类由组织细胞合成、分泌的小分子多肽类因子,特定的小分子化合物可作用于干细胞诱导其向视网膜感光细胞分化。目前,对干细胞体外培养,通过使用不同的诱导培养方案,探索干细胞向视网膜感光细胞分化的研究成为热点。早期,研究者们主要在共培养条件下采用小分子化合物诱导ESC向视网膜感光细胞分化,随着研究的进展,逐渐开始探索在无共培养条件下小分子化合物诱导ESC向视网膜感光细胞的分化以及小分子化合物诱导i PSC向视网膜感光细胞的分化。本文主要就小分子化合物促进ESC和i PSC向视网膜感光细胞分化的研究进展进行综述。     

三氧化二砷对人胃腺癌细胞株SGC-7901细胞核及线粒体作用的实验研究

目的:研究三氧化二砷(As203)对人胃腺癌细胞株SGC-7901的生物效应及其对线粒体和半胱氨酸蛋白酶家族-3(caspase-3)的作用.方法:通过MTT比色实验检测不同浓度As2O3对该细胞株的生长抑制作用;经Hoechst 33258染色后用荧光显微镜观察细胞核的形态变化;经过细胞线粒体膜电位检测区分凋亡细胞与正常细胞,并经流式细胞仪分析;caspase-3吸光度检测法测定As2O3组caspase-3的活化程度.结果:As2O3明显抑制SGC-7901人胃腺癌细胞的生长,抑制作用的强度呈时间依赖性(方差分析,P<0.01);Hoechst 33258染色后荧光显微镜观察细胞核固缩碎裂边集呈强蓝色荧光;线粒体膜电位检测法,流式细胞仪检测法,caspase-3吸光度检测法均检测到胃腺癌细胞的凋亡.结论:As2O3破坏线粒体跨膜电位和激活caspase-3活性可能是As2O3诱导人胃腺癌SGC-7901细胞凋亡的重要机制.     

当药黄素对H_2O_2诱导PC12细胞损伤的保护作用

研究当药黄素在H_2O_2诱导PC12细胞损伤中的作用。建立H_2O_2诱导的PC12细胞损伤模型,采用MTT法测定细胞活力,比色法测定细胞MDA和上清液LDH含量,以及SOD、CAT和GSH-Px酶活力,采用DCFH-DA荧光染色测定细胞ROS含量,JC-1染色测定细胞线粒体膜电位。当药黄素能够提高H_2O_2诱导损伤的PC12细胞的细胞活力,增加细胞内SOD、CAT和GSH-Px活力,降低MDA、LDH含量,抑制细胞内ROS增加,稳定细胞线粒体膜电位。当药黄素对H_2O_2诱导的PC12细胞损伤有保护作用。     

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