影响绿豆下胚轴原生质体遗传转化的因素

采用共培养法和ＰＥＧ法将外源基因导入绿豆下胚轴原生质体中,得到转化愈伤组织。根癌农杆菌经乙酰丁香酮等诱导物质以及低ｐＨ,低ＰＯ４＾３－预培养后,细菌Ｔ－ＤＮＡ的转移受到促进,ＧＵＳ基因表达活性明显提高。在ＰＥＧ介导的绿豆原生质体转化中,高Ｃａ＾２＋／ｐＨ有利于外源ＤＮＡ转移到植物细胞,ＧＵＳ活性较高。此外,质粒ＤＮＡ浓度和启动子类型均对外源基因的转移和表达有一定影响。     

细胞分裂素基因（T—cyt）启动子驱动下的GUS基因在烟草和马铃薯中的表达

构建了来自根癌农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ ｔｕｍ ｅｆａｃｉｅｎｓ） Ｔ－ＤＮＡ 的细胞分裂素基因（Ｔ－ｃｙｔ）启动子驱动下的ＧＵＳ基因的表达质粒,并用以转化烟草（Ｎｉｃｏｔｉａｎａ ｔａｂａｃｕｍ ｃｖ． Ｗ ３８）和马铃薯（Ｓｏｌａｎｕｍ ｔｕｂｅｒｏ－ｓｕｍ Ｌ． ｃｖ． Ｄｅｓｉｒｅｅ）,研究其在转基因植物中表达的定位。结果表明,Ｔ－ｃｙｔ启动子在转基因植株的根、茎、叶、块茎和萌发的种子中均可表达。其中在茎和块茎中的表达是不均一的：在维管束部分表达较强,在侧芽或叶柄的生长点及块茎的芽生长点表达活性较高。此外,在培养基中加入０．１ ｍ ｇ／ＬＢＡＰ,转基因烟草茎中ＧＵＳ基因的表达活性增强,而对ＮＡＡ 没有明显的反应。看来某些外源植物激素对Ｔ－ｃｙｔ启动子的活性有一定的诱导作用     

人主动脉硫酸乙酰肝素蛋白聚糖对培养的人血管壁细胞生长的作用

通过培养的人主动脉平滑肌细胞（ｈＡＳＭＣ）及脐静脉内皮细胞（ｈＵＶＥＣ）,应用３Ｈ－ＴｄＲ参入、Ｎｏｒｔｈｅｒｎｂｌｏｔ分析、逆转录多聚酶链反应（ＲＴ－ＰＣＲ）、放射免疫分析（ＲＩＡ）、和紫外比色法等技术观察了人主动脉中硫酸乙酰肝素蛋白聚糖（ＨＳＰＧ）对ｈＡＳＭＣ和ｈＵＶＥＣＤＮＡ合成的作用及对血小板源生长因子（ＰＤＧＦ）、ＰＤＧＦ受体、转化生长因子β（ＴＧＦ－β）、内皮素－１（ＥＴ－１）或碱性成纤维细胞生长因子（ｂＦＧＦ）基因表达和肾素－血管紧张系统（ＲＡＳ）的影响,结果显示,ＨＳＰＧ明显抑制培养的ｈＡＳＭＣ基础的ＤＮＡ合成（ｃｐｍ值为：１０３８５±３２６３ｖｓ,２５５４１±６４２１,Ｐ＜０．０１）及外源性ＰＤＧＦ诱导的ＤＮＡ合成（ｃｐｍ值为：９８７８±１９４７ｖｓ．１３４８１±４４ｌ０,Ｐ＜０．０５）;抑制ＰＤＧＦＡ链、ＴＧＦ－Ｂｐ和ＥＴ－１ｍＲＮＡ表达,提高ＰＤＧＦａ和β受体ｍＲＮＡ的表达;显著降低ｈＡＳＭＣ培养液中血管紧张素Ⅱ（ＡｎｇⅡ）的浓度和血管紧张素转换酶（ＡＣＥ）的活性,推测ＨＳＰＧ抑制ＰＤＧＦＡ链、ＴＧＦ－β及ＥＴ－１ｍＲＮＡ表达,降低ＡＣＥ活性及ＡｎｇⅡ浓度是其抑制ｈＡＳＭＣ增殖的重要机     

抗真菌蛋白Rs—AFPs基因在大肠杆菌中的表达

将抗真菌蛋白Ｒｓ－ＡＦＰ１和Ｒｓ－ＡＦＰ２全长ｃＤＮＡ插入表达质粒ｐＥＴ－２２ｂ／ＮｃｏＩ＋ＳａｃＩ位点,构建成融合蛋白表达载体ｐＲＡＦ１和ｐＲＡＦ２．将不含信号肽编码序列的Ｒｓ－ＡＦＰ１和Ｒｓ－ＡＦＰ２ｃＤＮＡ分别插入ｐＥＴ－２２ｂ／Ｎｃｏｌ＋Ｓａｃｌ和ｐＥＴ－２２ｂ／Ｎｄｅｌ＋ＳａｃＩ位点,构建成不含信号肽序列的融合蛋白表达载体ｐＲＡＦ３、ｐＲＡＦ４和非融合蛋白表达载体ｐＲＡＦ５和ｐＲＡＦ６．将构建的上述各种表达载体转化Ｅ．ｃｏｌｉＢＬ２１,挑菌落培养,ＩＰＴＧ诱导,使Ｒｓ－ＡＦＰｓ基因得到表达,并用体外抑菌试验检测表达产物的活性,结果表明,各种表达载体的表达产物均具有不同程度的抑菌活性,其中,ｐＲＡＦ３和ｐＲＡＦ４表达产物的抑菌活性较明显．     

用pKKH质粒在大肠杆菌中表达HuIFN－β

应用ＤＮＡ重组技术,将ＨｕＩＦＮ－β基因插入到质粒ｐＫＫＨ的ｔａｃ启动子下游,转化大肠杆菌ＪＭ１０１和ＪＭ１０３,经ＩＰＴＧ诱导,表达ＨｕＩＦＮ－β,收集并裂解细菌,用Ｗｉｓｈ－ＶＳＶ系统细胞病变抑制法检测生物学活性为２．１８×１０８－８．７×１０８ＩＵ／Ｌ菌液。经初步纯化ＳＤＳ－ＰＡＧＥ电泳可见分子量为２０ＫＤ较纯的表达带。     

Ⅰ型纤溶酶原激活物抑制剂cDNA在P.pastoris酵母菌中的表达和鉴定

将编码３７９个氨基酸残基的ＰＡＩ－１ｃＤＮＡ插入到含ＡＯＸ１启动子和ＰＨＯ１分泌信号肽序列的甲醇营养型酵母载体中,构建成表达质粒ｐＹＩＳ－１．表达质粒转化Ｐ．ｐａｓｔｏｒｉｓ甲醇营养型酵母细胞,筛选Ｈｉｓ＋Ｍｕｔ－表型的转化子,经低密度摇瓶培养,１％甲醇诱导表达７ｄ后,培液经ＳＤＳ－ＰＡＧＥ分析,ＰＡＩ－１生物活性测定和Ｗｅｓｔｅｒｎｂｌｏｔ证实表达出分子量为４３～５１ｋＤ的４条ＰＡＩ－１条带．表达的ＰＡＩ－１能有效地分泌到培液中,占培液总蛋白的２６％左右,达４ｍｇ／Ｌ培液;其比活性为１．１６×１０４ＡＵ／ｍｇ．不同分子量ＰＡＩ－１可能与其糖基化程度不同有关     

鼠Ⅰ型可溶性白细胞介素1受体基因在昆虫细胞的克隆和表达

白细胞介素１（ＩＬ－１）是一种重要的细胞因子,具有广泛的生物学活性。它通过与细胞表面的白细胞介素 １受体（ＩＬ－１Ｒ）结合而起作用。以杆状病毒为载体在昆虫细胞中克隆表达了小鼠Ｉ型可溶性白细胞介素１受体（ｓＩＬ－１　ＲＩ）基因。以ＮＩＨ／３Ｔ３细胞ＲＮＡ为模板,采用ＲＴ－ＰＣＲ方法扩增得到小鼠ｓＩＬ－ＩＲＩ的ｃＤＮＡ,克隆至杆状病毒转移载体ｐＡｃＧＰ６７Ｂ,将转移重组质粒与野生病毒ＡＣＮＰＶ ＤＮＡ共转染昆虫细胞Ｓｆ９,经同源重组得到重组杆状病毒ｒＡＣＮＰＶ。应用经纯化的ｒＡｃＮＰＶ感染昆虫细胞Ｓｆ９,表达获得重组的ｓＩＬ－１ＲＩ。经对亲和层析样品的ＳＤＳ－ＰＡＧＥ分析和对ＩＬ－１β生物活性阻断作用实验证实,表达产物能够与其配基结合,并且能够分泌至细胞培养上清中。     

PAI—2及其突变体的生物化学性质

为研究和比较纤深酶原激活剂抑制物２型（ｐｌａｓｍｉｎｏｇｅｎ ａｃｔｉｖａｏｒ ｉｎｈｉｂｉｔｏｒ ｔｙｐｅ ２,ＰＡＩ－２）及其突变体的生物化学性质,用ＰＣＲ、体外定点突变技术构建ＰＡＩ－２突变体ＰＡＩ－２ＣＤ和ＰＡＩ－２ＱｃＤＮＡ,将突变体ｃＤＮＡ与原核表达载体重组并转化怕杆菌。经诱导表达,ＳＤＳ－ＰＡＧＥ证实表达出相应蛋白质,均占全菌总蛋白的１４％。Ｗｅｔｅｒｎ印迹、溶圈抑制及纤维蛋白翻转板     

金鱼草基因转化和转基因植株再生

本实验采用根癌农杆菌ＬＢＡ４４０４（ｐ３５ＳＧＵＳＩＮＴ与金鱼草下胚轴切段共培养,将ＧＵＳ基因导入金鱼草细胞,通过不定芽发生途径获得抗Ｇ４１８再生植株．经ＤＮＡ／ＤＮＡ斑点杂交及ＧＵＳ活性原位组织检测初步证实外源基因ＧＵＳ已整合进金鱼草基因组并得到表达．     

牛生长激素基因在马铃薯中的表达

将牛生长激素基因ｃＤＮＡ 与Ｐａｔａｔｉｎ ＣｌａｓｓＩ启动子及ＮＯＳ３终止子连接,构建了表达载体ｐＰＢＧＴ． 用直接法将表达载体转入农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ ｔｕｍ ｅｆａｃｉｅｎｓ） ＬＢＡ４４０４（ｐＲＡＬ４４０４）菌株, 用此菌株转化马铃薯（Ｓｏｌａｎｕｍ ｔｕｂｅｒｏｓｕｍ ）得到再生植株． 经ＮＰＴⅡ活性检测,总ＤＮＡ ＰＣＲ和Ｓｏｕｔｈｅｒｎ ｂｌｏｔ证明目的基因已整合到马铃薯基因组中．ＲＮＡ 点杂交和Ｗｅｓｔｅｒｎ ｂｌｏｔ表明牛生长激素基因已在转基因马铃薯块茎中转录和表达     

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.