成年小鼠原代皮肤成纤维细胞的分离培养及其生物学特性

目的:建立一种周期短、成本低的成年小鼠原代皮肤成纤维细胞分离培养方法,并探索其生物学特性。方法:取8~12周龄BALB/c小鼠背部、尾尖、耳部皮肤,配制2种血清的细胞培养液,采用组织块贴壁法、酶消化法、酶消化组织块贴壁法进行原代皮肤成纤维细胞的培养,通过显微镜观察比较原代细胞的数量、形态、培养周期及纯度;通过免疫荧光、CCK-8、UVB辐照、流式细胞术进行生物学特性鉴别。结果:背部皮肤组织块贴壁使用Gibco胎牛血清培养7 d无细胞游出,CLARK特级胎牛血清细胞游出较多。背部皮肤经酶消化法得到细胞贴壁少;经组织块贴壁法细胞生长慢,培养周期长;酶消化组织块贴壁法细胞游出速度快、数量多、呈长梭形。尾尖取材量少,得到细胞少;耳部皮肤取材方便,但细胞纯度低。CCK8增殖曲线呈S型;相较于对照组,UVB辐照后细胞凋亡率增高17%。结论:CLARK特级胎牛血清、背部皮肤取材、酶消化组织块贴壁法是培养成年小鼠原代皮肤成纤维细胞最优的方案,可增加细胞得量、缩短培养周期,降低成本。     

人轮状病毒G1P[8]型感染树鼩原代小肠上皮细胞模型的建立

目的探究树鼩原代小肠上皮细胞的增殖特性,建立人轮状G1P[8]型病毒体外感染树鼩原代小肠上皮的细胞模型。方法采用胶原酶XI和中性蛋白酶I联合消化法获取树鼩原代小肠上皮细胞,经纯化和鉴定,用人轮状G1P[8]型病毒感染细胞,测定培养上清的病毒滴度和载量,并用Western blot和间接免疫荧光检测法检测人轮状病毒G1P[8]型VP6蛋白的表达情况,评价人轮状G1P[8]型病毒体外对树鼩原代小肠上皮细胞的感染性。结果分离的树鼩原代小肠上皮细胞经传代培养纯化,获得纯度达90%树鼩原代小肠上皮细胞。对树鼩原代小肠上皮细胞、原代肾细胞、HCT116细胞和MA104细胞进行轮状病毒易感性比较,确定树鼩原代小肠上皮细胞可以被人轮状病毒G1P[8]感染,培养72 h时病毒滴度可达到2.0×105TCID_(50)/m L。经Western blot和间接免疫荧光发现在人轮状G1P[8]型病毒感染树鼩原代小肠上皮细胞1~5 d均能检测到人轮状病毒VP6蛋白的表达和分布。结论确立了树鼩原代小肠上皮细胞的分离、纯化与培养方法,并建立了人轮状G1P[8]型病毒感染树鼩原代小肠上皮细胞的体外模型。     

树鼩脑星形胶质细胞的体外培养及纯化

本文旨在建立低等灵长类动物树鼩(Tupaia belangeri)脑星形胶质细胞(astrocyte,AS)原代培养及纯化的技术,为利用新型实验动物树鼩进行研究工作而建立体外模型。将新生树鼩大脑皮质机械分离,置于4°C冰箱20min以损伤神经元,皮质组织块用胰蛋白酶消化后制成细胞悬液,分次贴壁去除成纤维细胞,培养的混合细胞在每次换液时用0.005%胰蛋白酶轻柔漂洗去除神经元。细胞长满培养瓶底面积约70%时,用0.025%胰酶溶液静置消化,至肉眼可见一层白色薄膜从瓶底脱落时终止消化,此白色薄膜即为AS层。AS传至第三代时,用抗胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)抗体进行免疫组织化学染色和免疫荧光染色鉴定。结果显示,本方法所得的树鼩脑AS的纯度可达98%以上。该结果提示,这种通过分次贴壁法结合差异消化的培养及纯化技术可获得高纯度的树鼩脑AS,为建立神经系统疾病新的体外细胞培养模型打下了基础。     

树鼩原代小胶质细胞的分离培养、纯化与鉴定

本文旨在建立树鼩(Tupaia belangeri)小胶质细胞原代培养及纯化的方法,为利用新型实验动物树鼩进行相关研究工作提供实验材料。将新生树鼩大脑皮质机械分离,皮质组织块用胰蛋白酶消化后制成细胞悬液;培养9～10 d后,分别采用直立手拍法、温和胰酶消化法以及恒温振荡法分离纯化树鼩小胶质细胞,通过差速贴壁进一步纯化。荧光显微镜下,利用小胶质细胞的特异性标记物CD11b抗体进行鉴定。结果显示,小胶质细胞分离培养第3天时呈静息状态,表现为梭形、杆状、分支状等不规则形态。细胞免疫荧光CD11b呈阳性。不同纯化方法细胞免疫荧光并计数显示,直立手拍法所获得的细胞产量明显高于恒温振荡法(P 0.05),细胞阳性率( 96%)明显高于温和胰酶消化法( 90%,P 0.05)。直立手拍法可获得产量及纯度高的树鼩原代小胶质细胞。     

成年SD大鼠心肌原代成纤维细胞分离及培养的优化方案

目的:摸索及优选成年SD大鼠心肌原代成纤维细胞的体外分离、培养及鉴定的实验方法。方法:将成年SD大鼠心脏剪成小组织块,采用以下四种方案(A:0.08%胰酶+0.1%胶原酶II消化15 min,B:0.2%胶原酶II消化15 min,C:0.2%胶原酶II消化60min,D:0.2%胶原酶II消化90 min)提取成年大鼠心脏原代成纤维细胞,再通过差速贴壁分离方法培养原代成纤维细胞。采用倒置显微镜观察成纤维细胞的基本形态特征,并进行Vimentiin免疫荧光染色对培养的原代细胞进行荧光鉴定;采用台盼兰染色对培养的原代成纤维细胞存活率进行鉴定;采用细胞计数对培养的成纤维细胞生长趋势进行鉴定。结果:四种方法均能培养成纤维细胞,但单酶消化60 min可一次性提取较多细胞,并且细胞状态佳,3 d即可传代。72 h成纤维细胞Vimentin免疫荧光染色阳性率高达97%。台盼兰染色可见其细胞死亡率明显降低,并且细胞计数可见细胞生长状态极佳。结论:单酶消化60 min是提取成年SD大鼠心肌原代成纤维细胞的高效、快速、稳定的实验方法,为心脏疾病的基础及临床研究提供了较为理想的细胞学实验模型。     

前列腺基质细胞的原代培养方法

目的:建立一种操作简单、成功率高、重复性好的前列腺增生组织原代基质细胞(PSC)培养方法。方法:采用胶原酶消化法、组织块贴壁法和胰酶消化组织块贴壁法,从70岁及以上男性的良性前列腺增生组织中分离培养PSC,通过显微镜观察比较PSC的数量、形态、培养周期,用免疫荧光染色法鉴定PSC的纯度。结果:胶原酶消化法得到的贴壁细胞少,细胞体积较小且形态无法铺展,增殖能力较弱;组织块贴壁法培养72h后细胞会从组织边缘缓慢爬出,生长周期长;胰酶消化组织块贴壁法,细胞培养7d后基本融合,折光性强,细胞多呈长梭形,通过免疫荧光染色鉴定,基质细胞纯度在95%以上。结论:利用胰酶消化组织块贴壁法建立了一种易行、高效且重复性好的前列腺增生组织基质细胞培养方法。     

大鼠主动脉内皮细胞和平滑肌细胞的原代培养及生物学特性比较

目的培养大鼠主动脉平滑肌细胞和内皮细胞,细胞纯化与鉴定,比较生物学特性的差异。方法采用血管环贴壁法培养动脉内皮细胞,组织块贴壁法培养动脉平滑肌细胞,并采用有限稀释法挑选内皮细胞单克隆,免疫细胞荧光鉴定二者的特异性标志,相差显微镜观察二者单个细胞及细胞群体在形态上的差异性,CCK-8试剂盒检测细胞的增殖,比较二者对胰酶消化,粘附,冻存后复苏的情况。结果血管环贴壁法成功培养血管内皮细胞,组织块培养法成功培养出血管平滑肌细胞,内皮细胞能够形成单克隆集落,培养的细胞均表达相应的特异性标志,内皮细胞增殖速度和平滑肌细胞有差异,内皮细胞对胰酶的耐受性较差,内皮细胞粘附所需时间短,对冻存后的耐受性较好。结论组织块贴壁法适合内皮细胞和平滑肌细胞的培养,有限稀释法能够纯化原代培养的内皮细胞,大鼠主动脉平滑肌细胞和内皮细胞在细胞形态、增殖、粘附、对胰酶的反应、冻存后复苏均存在差异。     

牛成纤维细胞的分离与体外培养

研究了牛胎儿和成年牛皮肤组织成纤维细胞的分离、培养、纯化方法和生长特征。通过组织块贴壁培养和分离单细胞接种培养均能获得原代牛皮肤细胞。用2.5 g/L胰蛋白酶+1mmol/L EDTA和5 g/L胶原酶I联合消化牛皮肤组织较2.5 g/L胰蛋白酶+1 mmol/L EDTA消化,得到更多的单个细胞,两者之间差异极显著(P<0.01),但其死细胞比率却有较大升高;2.5 g/L胰蛋白酶+1 mmol/L EDTA消化牛胎儿组织得到的单细胞数显著高于皮肤组织消化后得到的细胞数(P<0.01),死细胞比率也高于同种酶消化的皮肤组织。分离纯化的胎儿和皮肤成纤维细胞的生长曲线都正常且相似。2.5 g/L胰蛋白酶+1 mmol/L EDTA消化贴壁细胞后死细胞率明显高于用0.5g/L胰蛋白酶+0.53 mmol/L EDTA消化的细胞(P<0.05);培养24 h后细胞贴壁率前者要明显低于后者(P<0.05)。用0.5 g/L胰蛋白酶轻度消化混杂生长的成纤维细胞和上皮样细胞,经过反复贴壁传代2～3代,可得到较纯的成纤维细胞。     

树鼩视网膜微血管内皮细胞永生化细胞株的建立及鉴定

目的 建立树鼩视网膜来源的微血管内皮细胞的体外分离培养技术以及永生化细胞株，为体外利用树鼩视网膜微血管内皮细胞开展相关研究提供新的实验材料。方法 利用Ⅱ型胶原酶、分散酶和DNaseⅠ酶消化法分离培养出原代视网膜微血管内皮细胞，利用差速消化法纯化内皮细胞，然后利用携带SV40T基因的慢病毒转染细胞，再挑取单克隆后进行传代培养。对传至50代以上的细胞进行形态学观察、免疫荧光鉴定以及核型鉴定。结果 采用混合酶消化法能够分离获得微血管内皮细胞，纯化后的细胞呈不规则多角形和梭形。经慢病毒转染后的细胞传代培养后细胞形态一致，到第50代时细胞形态结构仍较好。细胞免疫荧光结果显示标志性蛋白VWF、CD34、Claudin1、ZO-1和永生化SV40T表达阳性。生长曲线结果显示：细胞生长旺盛，第2～4天时处于对数生长期，第4天进入平台期。细胞核型结果显示：染色体数与树鼩染色体相同，即所获取的细胞为永生化的树鼩视网膜微血管内皮细胞。结论 成功建立的树鼩视网膜微血管内皮细胞永生化细胞株具有较好的形态结构与功能，为视网膜病变及眼科相关疾病的研究提供了新的实验材料。     

胶原酶Ⅰ消化法体外分离培养奶牛乳腺上皮细胞

为获得纯净的奶牛乳腺上皮细胞,该研究采用胶原酶I消化法,在不添加外源激素及生长因子的条件下培养奶牛乳腺上皮细胞。采用差时消化与差速贴壁方法,对奶牛乳腺上皮细胞进行纯化。采用Western blot方法检测细胞中β-酪蛋白(β-casein,CNS2)的水平。通过免疫荧光技术对细胞进行鉴定。结果显示,纯化后的细胞呈现典型的"铺路石"或"鹅卵石"样。细胞角蛋白-18(cytokeratin-18,CK-18)反应呈阳性,波形蛋白反应呈阴性。细胞传至15代冻存并复苏后生长状态依然良好。这提示,胶原酶I消化法在不添加外源激素及生长因子的条件下可以获得奶牛乳腺上皮细胞,以用于后续实验。     

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.     

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.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.