香蕉RAPD分析初步研究

比较了不同提取方法对香蕉植株不同部位组织提取 DNA的质量及其 PCR扩增结果 ,对香蕉 RAPD分析中引物种类和浓度 ,复性温度 ,d NTPs,Taq DNA聚合酶浓度 ,热循环数等因素进行了比较影响分析。结果表明 ,虽然改良的 SDS法、CTAB法和 PVP法提取的植株嫩叶和吸芽 DNA提取量和纯度各不相同 ,但其 PCR扩增结果基本相同 ;相同克隆不同植株的 DNA其 PCR扩增结果也基本相同 ;建立了适合香蕉大规模 DNA多态性分析 RAPD反应体系 :2 5 μL反应液中 ,含 1倍缓冲液 ,0 .2 m Md NTPs,0 .3 2 p M随机引物 ,IUTaq酶 ,2 0 ng模板 DNA;反应循环数为 45 ,热循环条件为 94°C,1 min;3 7°C,1 min;72°C,1 .5 min;之前为 94°C,5 min;之后为72°C,1 0 min。在筛选的 2 49个随机引物中 ,有 1 8个在 7个品种上都能扩增出 3～ 1 0条比较清晰条带。     

杜鹃花RAPD条件的优化

以井冈山杜鹃为材料建立了杜鹃花RAPD反应优化体系 ,用于杜鹃花遗传多样性分析 ,以改进的CTAB法提取杜鹃花属植物杜鹃花叶片总DNA ,分别测试了镁离子浓度、dNTP浓度、模板DNA含量、引物浓度、DNA聚合酶量对反应结果的影响。通过各因子的组合比较 ,建立了杜鹃花RAPD优化体系 :2 0 μLPCR反应体积 ,10×Taq酶配套缓冲液 (2 μL) ;1UTaq酶 ;模板DNA10ng ;13.32pmol引物 ;2 .12mmol·L- 1 MgCl2 ;dATP、dCTP、dGTP和dTTP各 0 .15mmol·L- 1 。     

濒危植物七子花RAPD条件的优化

以改进SDS法抽提濒危植物七子花嫩叶总DNA ,进行随机扩增多态DNA(RAPD)分析 ,分别测试了镁离子 ,dNTP ,模板DNA含量 ,引物和DNA聚合酶量对反应结果的影响 ,通过各因子的组合研究 ,可知七子花RAPD分析较适宜的扩增条件是 :1 5μLPCR反应体积 ,1×Taq酶配套缓冲液 (1 0mmol/LTris·HClpH 9.0 ,50mmol/LKCl,0 .1 %TritonX_1 0 0 ) ,2 .5mmol/LMgCl2 ,2UTaq酶 (上海华美公司 ) ,1 0ng模板DNA ,2 0pmol引物 (上海Sangon公司 ) ;dATP、dCTP、dGTP、dTTP各 0 .1mmol/L。     

Hg~(2+)胁迫对浮萍体细胞DNA一级结构和抗氧化酶系的损伤(英文)

主要从DNA一级结构及抗氧化酶系变化两方面 ,研究了Hg2 + 胁迫下浮萍体细胞的损伤。结果表明 :运用随机扩增多态性DNA法 (RandomamplifiedpolymorphismDNA ,RAPD)和DNA梯法 (DNALadder) ,5～ 1 0mg·L- 1 Hg2 +处理组可检测到基因组DNA的明显损伤 ,2 0mg·L- 1 Hg2 + 已导致细胞坏死 ;RAPD法较DNALadder法更灵敏。本文还发现 ,活性氧和抗氧化酶系很可能参与了浮萍体细胞凋亡过程。低浓度的Hg2 + 胁迫可刺激抗氧化酶活性升高 ,以清除体内活性氧 ,而一旦活性氧水平超出一定域值 ,抗氧化酶活性急速下降 ,导致细胞凋亡     

苦丁茶冬青的RAPD影响因素及实验条件的优化

以苦丁茶冬青为材料研究随机扩增多态DNA(RAPD)的影响因素及各种实验条件优化。研究结果表明：模板DNA的浓度适宜范围为20ng／反应-80ng／反应RAPD均可得到一致的结果;dNTVs的适宜浓度范围为200μmol／L-400μmol／L;Mg^2 适宜浓度范围为1．5mmol／L-2．0mmol／L;其合适的复性温度为35—37℃;2min的延伸时间,45次热循环。按照此优化的RAPD条件进行重复实验,实验结果重现性良好,因而确定了苦丁茶冬青RAPD反应体系之最佳的实验条件。     

广霍香的组织培养

1　植物名称　广霍香 (Pogostemoncablin)2　材料类别　嫩叶、嫩枝。3　培养条件　芽诱导与增殖培养基 :( 1 )MS +4PU 30 (四川成都施特优化工厂生产 ) 0 .2 5mg·L- 1 + 3%蔗糖 + 0 .8%琼脂 ;( 2 )MS + 6 BA 0 .5mg·L- 1 + 3%蔗糖 + 0 .8%琼脂。生根培养基 :( 3)MS +NAA 0 .2mg·L- 1 + 1 .5 %蔗糖 + 0 .8%琼脂。上述培养基pH均为5 .8,培养温度为 ( 2 5± 2 )℃ ,光照度为 1 2 0 0lx左右 ,每天光照 1 2h。4　生长与分化情况4.1　不定芽和叶腋丛生芽诱导与增殖　将广霍香嫩枝、嫩叶用自来水冲冼干净后 ,以 0 .1 %升汞表面消毒 1 0m…     

大叶秦艽的组织培养与植株再生

以秦艽的叶和下胚轴为外植体,成功地诱导出愈伤组织和再生植株.诱导愈伤组织最合适的培养基为附加2 m g·L- 1 2 ,4 - D和0 .5 mg·L- 1 6 - BA的MS培养基,诱导率可达到10 0 % .愈伤组织转移到附加2 mg·L- 12 ,4 - D和0 .5 mg·L- 1 KT和5 0 0 m g·L- 1 L H的MS培养基上进行继代培养,增殖后的愈伤组织转移到附加0 .1mg·L- 1 2 ,4 - D和0 .5 m g·L- 1 6 - BA的MS分化培养基上进行分化,其分化率可达到86 .6 7% ,将分化出的芽转接到不加激素的MS上,结果可生长出大量的分化苗.     

线粒体DNA数目不同的人角质形成细胞模型的建立

该研究采用溴化乙锭(ethidium bromide,Et Br)对人永生化角质形成细胞(HaCaT)进行诱导,采用RT-PCR法、MTT法和健那绿染色技术联合鉴定Et Br对HaCaT细胞线粒体DNA(mitochondrial DNA,mt DNA)拷贝数的影响,建立不同mt DNA拷贝数目的HaCaT细胞模型。结果显示,HaCaT细胞经100 ng/m L和50 ng/m L Et Br分别处理10 d后,细胞形态随着处理时间的延长发生改变,由规则铺路石形状逐渐变圆,某些细胞体积变小,成团生长,细胞膜边缘不光滑,且随着mt DNA数目的减少,细胞增殖速率明显下降。RT-PCR分析结果显示,与对照组相比,50 ng/m L和100 ng/m L Et Br处理10 d的HaCaT细胞中,mt DNA的拷贝数分别减少了52.9%和97.6%[以线粒体DNA脱氢酶1(mitochondrial NADH dehydrogenase 1 gene,ND1)与甘油醛-3-磷酸脱氢酶(glyceraldehyde-3-phosphate dehydrogenase,GAPDH)的比值来表示mt DNA的相对拷贝数变化情况]。健那绿染色显示,对照组HaCaT细胞中可见分散存在的蓝绿色线粒体颗粒,100 ng/m L Et Br处理10 d后的HaCaT细胞中,显微镜下蓝绿色线粒体颗粒明显减少。综上所述,该研究证明了HaCaT细胞可通过Et Br诱导被成功培养成ρ–细胞,且Et Br浓度与HaCaT细胞mt DNA拷贝数的变化在一定的范围内存在着剂量–效应关系。     

珍珠菜提取物抗肿瘤作用的初步研究

观察灌服珍珠菜提取物对小鼠肉瘤 ( S1 80 )的抑制作用 ,用相同方法跟踪珍珠菜的抗肿瘤有效部位。用紫外分光光度法 ,观察了珍珠菜提取物对环磷酰胺造成骨髓抑制的保护作用 ;采用 MTT法观察不同浓度珍珠菜提取物对人白血病 HL - 6 0及 K 5 6 2细胞的体外抑制作用。结果表明珍珠菜浸膏 ( 40 0 0 m g/ kg· d)、石油醚部位 ( 2 0 0 m g/kg· d)、氯仿部位 ( 2 0 0 m g/ kg· d)、乙酸乙酯 ( 2 0 0 mg/ kg· d)部位、正丁醇部位 ( 2 0 0 mg/ kg· d)及水溶性部位 ( 2 0 0mg/ kg· d)对小鼠肉瘤 ( S1 80 )抑瘤率分别为 5 2 .74%,16 .5 1%,2 8.41%,42 .17%,48.2 1%,2 5 .2 4%;小鼠灌服环磷酰胺 ( 2 5 mg/ kg· d)能引起骨髓抑制而使骨髓中 DNA含量下降 ,如同时灌服珍珠菜浸膏 ( 2 0 0 0 m g/ kg· d)则可使小鼠骨髓 DNA含量恢复至接近正常水平 ;珍珠菜总黄酮提取物 ( 2 10μg/ m L )、乙酸乙酯部位 ( 180μg/ m L )、正丁醇部位 ( 2 10μg/ m L )作用 48h对 HL - 6 0细胞的抑制率分别为 35 .6 6 %,45 .85 %,42 .36 %;IC5 0分别为 92 .85 ,16 4.93,40 2 .6 1μg/ m L ;对 K5 6 2细胞抑制率为 5 9.94%,70 .34%,77.98%;IC5 0分别为 17.6 4,5 2 .5 3,6 4.70μg/ m L。因此 ,珍珠菜提取物对小鼠肉瘤 ( S180 )有显     

Hg2+胁迫对浮萍体细胞DNA一级结构和抗氧化酶系的损伤(英文)

 主要从DNA一级结构及抗氧化酶系变化两方面,研究了Hg2+胁迫下浮萍体细胞的损伤。结果表明：运用随机扩增多态性DNA法（Random amplified polymorphism DNA, RAPD）和DNA梯法（DNA Ladder）,5～10 mg·L-1　Hg2+处理组可检测到基因组DNA的明显损伤,20 mg·-1 Hg2+已导致细胞坏死;RAPD法较DNA Ladder法更灵敏。本文还发现,活性氧和抗氧化酶系很可能参与了浮萍体细胞凋亡过程。低浓度的Hg2+胁迫可刺激抗氧化酶活性升高,以清除体内活性氧,而一旦活性氧水平超出一定域值,抗氧化酶活性急速下降,导致细胞凋亡。      

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.