小麦生长素结合基因 TaABP1-D的定位表达及染色体定位

生长素影响了植物生长发育的诸多过程。生长素结合蛋白 ABP1 (auxin binding protein) 作为一种生长素受体,在质膜上生长素诱导的快速反应中起重要作用。小麦中已经克隆得到了TaABP1-D,但其在细胞中的作用位置以及在染色体定位情况仍不明确。本实验利用洋葱表皮细胞瞬时表达系统对小麦生长素结合基因 TaABP1-D进行亚细胞定位,表明TaABP1-D蛋白为膜蛋白,存在于细胞质和细胞膜中;同时利用中国春缺体-四体材料和信息学方法,将TaABP1-D定位在小麦5D染色体长臂的近着丝粒位置上,距两侧EST标记BE490079和BE405060的遗传距离分别为0.51 cM和0.28 cM。     

PIN蛋白在生长素极性运输中的作用

PIN蛋白是生长素流出栽体,它在细胞中的不对称分布决定细胞间生长素流方向.PIN蛋白网络系统决定生长素的极性运输,为植物体各部位的细胞提供了特异的位置和方向信息.从细胞水平上介绍PIN蛋白在生长素极性运输中的作用及对PIN蛋白功能调节的研究进展.     

KPNB1和Ran蛋白共同介导新城疫病毒基质蛋白的入核转运

【目的】鉴定与新城疫病毒(Newcastle disease virus,NDV)基质蛋白(matrix protein,M)入核相关的细胞蛋白,以阐明NDV M蛋白细胞核定位的分子机制。【方法】从鸡胚成纤维细胞中分别克隆核转运受体蛋白KPNA1–KPNA6和KPNB1基因,将其构建到真核表达载体,并与表达NDV M蛋白的重组真核表达载体分别共转染HEK-293T细胞,通过免疫共沉淀方法鉴定与NDV M蛋白相互作用的核转运受体蛋白。另外,将M蛋白与Ran蛋白突变体或与M蛋白互作的核转运受体蛋白缺失体分别共表达,通过荧光共定位确定M蛋白入核转运相关的细胞蛋白。【结果】构建的重组真核表达载体在HEK-293T细胞中能够正确表达;通过间接免疫荧光观察发现,重组蛋白中除Myc-KPNA2蛋白定位在细胞质外,其它核转运受体蛋白均与M蛋白表现出相同的细胞核定位。免疫共沉淀试验结果表明,M蛋白与KPNA1蛋白和KPNB1蛋白均存在相互作用。进一步通过荧光共定位观察发现,M蛋白与KPNA1蛋白缺失体(DN-KPNA1)共表达不改变M蛋白的细胞核定位,而与KPNB1蛋白缺失体(DN-KPNB1)共表达后导致M蛋白变为细胞质定位,说明M蛋白入核转运需要KPNB1蛋白的参与。另外,将M蛋白与Ran蛋白突变体Ran-Q69L共表达,荧光观察发现M蛋白同样由细胞核定位变为细胞质定位,说明M蛋白入核转运还需要Ran蛋白的辅助。【结论】KPNB1和Ran蛋白共同介导NDV M蛋白的入核转运,其过程是KPNB1蛋白首先和M蛋白发生相互作用并形成复合物,然后通过Ran蛋白的辅助作用完成入核转运。     

定位转基因所在的小麦基因组的细胞遗传学方法

本文设计了一种利用细胞遗传学原理定位转基因小麦部转基因所在的基因组的系统方法,并对该方法的有效性和可靠性进行了验证。该方法利用分别含有AABB、AADD和BBDD基因组的小麦近缘四倍体与等测转基因小麦杂交,F1一倍体与同源非转化品种回交,根据回交群体中在抗性基因控制的性状上的分离比例以及各个体的染色体数目分析,从而对转基因小麦中转基因所在的基因组进行定位,该方法简单、可靠,实用性强,可供相关研究采用。     

粗山羊草抗条锈病新基因YrY206遗传分析和微卫星 标记

从小麦野生近缘属——粗山羊草中挖掘小麦条锈病抗病基因, 拓展小麦抗病性的遗传基础。利用抗小麦条锈病与感小麦条锈病的粗山羊草间杂交, 从粗山羊草[Aegilops tauschii (Coss.) Schmal] Y206中鉴定出1个显性抗小麦条锈病基因, 暂定名为YrY206。应用分离群体分组法(Bulked segregant analysis, BSA)筛选到Wmc11a、Xgwm71c、Xgwm161和Xgwm183标记, 与该基因之间的遗传距离分别为4.0、3.3、1.5和9.3 cM。根据连锁标记所在小麦微卫星图谱的位置, YrY206被定位在3DS染色体上。分析基因所在染色体的位置、抗病性特征, 认为YrY206是一个新的抗小麦条锈病基因。     

黄瓜嫩果皮色基因QTL定位分析

以黄瓜(Cucumis sativus L.)嫩果皮绿色自交系1613(P1)和嫩果皮白色自交系JD7(P2)为试验材料构建重组自交系(RIL)群体(142个株系),对各株系嫩果皮色进行表型鉴定,利用重测序技术对各自交系进行基因分型,结合表型和基因型数据进行QTL定位研究。结果表明F1黄瓜嫩果皮颜色表现为绿色,并将控制嫩果皮颜色的基因定位到黄瓜第3号染色体上,在3号染色体35511129~39711114区段内定位到成簇分布的3个位点,它们在连锁图谱上的位置分别为1. 01 c M、3. 31 c M和6. 01 c M处,与两翼标记的连锁距离分别为1. 01 c M/0. 09 c M,0. 21 c M/0. 29 c M,0. 11 c M/0. 19 c M。通过生物信息学分析预测出16个候选基因,其中Csa3G904080、Csa3G904100、Csa3G903500和Csa3G902950极有可能是调控黄瓜果实颜色的关键基因。     

抗白粉病基因PmCH1302的遗传分析及染色体定位

CH1302是以来源于中间偃麦草的八倍体小偃麦TAI7047为桥梁亲本选育的高抗白粉病的小麦新品系,对白粉菌多个流行小种均表现出良好抗性。为了解其抗白粉病基因来源及其在染色体上的位置,对绵阳11×CH1302的F_1、F_2及F_(2∶3)家系进行了遗传分析,推断其抗白粉病基因可能来源于中间偃麦草,暂将其命名为PmCH1302。利用i Select 90K SNP芯片对抗、感病池进行扫描,发现位于2AL染色体上的多态性位点最多,为313个,占全部多态性位点的9.79%,且集中于2AL染色体100~105 c M和150~155 cM两个区域附近。在上述位点选取SSR标记,筛选出3对与Pm CH1302连锁的分子标记,Xwmc522、Xgwm356和Xgwm526,其中Xgwm356和Xgwm526位于Pm CH1302两侧,连锁距离分别为3.1 c M和7.8 cM。利用遗传图谱以及中国春缺体、双端体将PmCH1302定位于小麦2AL染色体上。进一步与位于2AL上的Pm4、Pm50比较发现,PmCH1302可能是位于2AL上的一个新基因或等位基因。     

新基因 P15RS 表达产物在人胃癌细胞细胞周期中定位的研究

P15RS是在p15INK4b高表达的人黑色素瘤细胞MLIK6 G1期中发现和克隆的新基因.研究表明,该基因可能在G1期作为增殖负调因子起作用.为了观察P15RS基因产物在细胞中的定位,构建了表达P15RS-EGFP融合蛋白的真核表达质粒pEGFP-P15RS.用绿色荧光蛋白GFP作为报告基因,以人胃癌细胞BGC-823为实验模型,将pEGFP-P15RS转染BGC-823细胞.实验表明,P15RS基因表达产物在G1期、S期和G2期均定位于细胞核内,未见在核仁中分布,M期凝缩的染色体上未见.因此,P15RS可能定位在核质中.     

生长素输出载体蛋白PIN1在作物根和胚中的亚细胞定位

生长素输出载体在植物发育中起非常重要的作用。然而,生长素输出载体蛋白PIN1在农作物水稻、小麦、玉米和大豆的根和胚中的亚细胞定位尚不清楚。该研究首先分析了OsPIN1b和它的同源物的氨基酸序列特征,发现小麦(TaPIN1)、玉米(ZmPIN1b)和大豆(GmPIN1b)中的PIN1序列与水稻的OsPIN1b序列分别具有61.5%、62.5%、61.9%的相似性。然后根据水稻‘日本晴’(‘Nipponbare’)的OsPIN1b的氨基酸序列,人工合成OsPIN1b多肽并注射健康的新西兰白兔获得了抗兔的OsPIN1b多克隆抗体,在通过免疫印迹方法检测抗兔的OsPIN1b多克隆抗体的有效性后,发现可以利用该抗体有效检测到水稻叶片及根中OsPIN1b的表达。为检测OsPIN1及其同源物在不同作物胚根和胚中子叶细胞的定位,利用制备的抗兔的OsPIN1b多克隆抗体并通过免疫组化实验,发现水稻的OsPIN1b、小麦的TaPIN1和玉米的ZmPIN1b非极性定位在早期的胚根和胚中子叶表皮细胞的细胞质膜上,大豆中的GmPIN1b非极性定位在胚根表皮细胞的质膜上,而在胚的子叶细胞中是胞质定位。为进一步检测水稻中OsPIN1b的亚细胞定位,对水稻根分生区表皮细胞用蛋白质转运抑制剂BFA (Brefeldin A)及抗兔的OsPIN1b多克隆抗体处理后,进行免疫组化实验,结果发现水稻中的OsPIN1b可以通过胞吞转运途径从水稻根表皮细胞膜进入细胞质中。该研究利用抗兔的OsPIN1b多克隆抗体有效检测了OsPIN1b及其同源物在水稻、小麦、玉米和大豆的胚根表皮细胞及胚中子叶表皮细胞的亚细胞定位,这将有助于进一步揭示生长素输出载体OsPIN1b及其同源物通过调控生长素极性运输而参与作物发育的作用机制。     

龙眼体胚发生过程生长素响应因子DlARF5a的克隆及表达分析

以龙眼松散型胚性愈伤组织为材料,采用RT-PCR和RACE技术克隆获得生长素响应因子ARF5acDNA全长序列,利用实时荧光定量法检测其在龙眼体胚不同发育时期的转录水平,并将其与绿色荧光蛋白(GFP)构建成亚细胞定位载体侵染洋葱表皮细胞。结果表明:龙眼ARF5a(命名为DlARF5a,GenBank登录号为KF739401)的cDNA序列全长为3 322bp,其中开放阅读框为2 829bp,212bp 5′非编码区,258bp 3′非编码区,编码942个氨基酸。生物信息学预测显示,DlARF5a编码蛋白具有B3、Auxin-resp和AUX-IAA保守区与结构功能域,中间区域富含谷甘氨酸、丝氨酸和亮氨酸,是一个定位于细胞质的具有促进转录活性功能的水溶性蛋白。系统进化树分析表明,该基因编码的氨基酸序列与大豆的亲缘关系最近。qRT-PCR检测显示,DlARF5a在龙眼球形胚和鱼雷形胚时期表达显著增强,而在6个发育阶段中子叶形胚的表达量最低,推测DlARF5a参与龙眼体胚中鱼雷胚时期的形态建成。共聚焦显微镜观察结果显示,未添加外源生长素IAA的DlARF5a蛋白定位于细胞质中,而经外源生长素处理的DlARF5a蛋白在细胞膜、细胞质和细胞核中均有表达,推测龙眼生长素响应蛋白DlARF5a能够响应外源生长素IAA而改变其在细胞中的空间位置。     

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.