"全明星"草莓叶片遗传转化体系的建立

采用根癌农杆菌介导法进行nptⅡ基因对全明星草莓叶片的遗传转化研究,对转化过程中的一些因素进行了探讨：全明星叶片对卡那霉素的敏感实验,得出最适筛选浓度为30mg／L,羧苄青霉素的最适抑菌浓度为450mg／L;50μmol／L乙酰丁香酮(AS)的加入可提高GUS的瞬时表达率;10～15min是最适合叶片侵染的时间;共培养3d对叶片转化较适宜,得到抗卡那霉素的抗性芽的频率为1．1％,初步鉴定是转化芽。为草莓的遗传转化奠定基础。     

双价抗病基因导入籽瓜的遗传转化研究

以籽瓜主栽品种新籽瓜2号、五原籽瓜等为研究材料,用苗龄1-3d的子叶切块作外植体,不定芽诱导培养基为MS 6-BA2mg/L IBA 0.1mg/L,芽伸长培养基为MS KT0．2mg／L,诱导生根的培养基是MS IAA0．5mg／L。籽瓜遗传转化研究结果表明农杆菌感染时间以10min,共培养时间以2d为合适。共获得抗卡那霉素100mg／L的试管苗41个,PCR检测呈阳性的有15株,转化率为34．9％。该研究初步建立了籽瓜的遗传转化体系和转化体的检测体系。     

PSAG12-ipt嵌合基因转化马铃薯体系的研究

以根癌农杆菌介导法将PSAG12-ipt嵌合基因导入马铃薯栽培品种,对影响马铃薯遗传转化的多种因素进行系统研究.结果表明:马铃薯茎段分化效率高于叶片,马铃薯愈伤诱导和芽分化最适培养基为MS+6-BA 0.25mg/L+NAA 0.25mg/L+2,4-D 0.25mg/L,添加1%Na2SO3能有效防止褐化;茎段愈伤诱导和分化苗生根最适的Kan浓度分别为50mg/L和75mg/L;外植体预培养2d,OD600为0.2～0.5的农杆菌浓度侵染8min、共培养3d后进行选择培养能有效地提高植株再生能力.用PSAG12和ipt双重PCR检测再生植株,阳性转化率为65.8%.Southern blotting结果表明,转基因植株多以单拷贝形式整合进马铃薯基因组中.     

根癌农杆菌介导D32基因

以烟草品种'中烟99'的无菌苗叶片为转化受体材料,通过根癌农杆菌C58C1介导对大豆中克隆的抗逆性基因D32进行转化,获得了抗卡那霉素的再生植株,并对转化植株进行了PCR检测.结果表明,烟草叶片分化和再生的卡那霉素选择压力为150 mg/L;外植体预培养对转化率有影响;优化的烟草转化方法是:经预培养2 d的外植体用OD600值为0.7的菌液侵染5 min, 共培养2 d后用无菌水冲洗5～6次,羧苄青霉素(Cb)和头孢霉素(Cef)浓度为400 mg/L的脱菌液浸泡120 min,超净工作台上吹风60 min,于筛选分化培养基生长50 d,可获得26.7%卡那抗性苗.对抗性植株经PCR检测证明,外源D32基因已初步整合到烟草基因组中.     

农杆菌介导巨桉Eg5高效遗传转化

以巨桉(Eucalyptus grandis)无性系Eg5叶片为外植体, 探讨了农杆菌(Agrobacterium tumefaciens)侵染时间、共培养pH值和共培养时间对瞬时转化效率的影响, 分析了不同筛选策略对遗传转化植株筛选效果的影响。结果表明, 外植体侵染45分钟, 共培养pH值为5.8, 共培养3天所得到的瞬时转化效率最高; 逐步提高卡那霉素(Km)浓度筛选转基因植株有效, 筛选率达到15%, 转化率达到0.26%。经过GUS染色分析和PCR检测, 证实为转基因植株。     

蝴蝶兰F3′5′H基因转化OT杂种百合Robina的研究

为了定向育种获得蓝色百合,该研究以百合Robina为蓝色基因最佳受体,以其花丝诱导产生的胚性愈伤组织和再生小植株小鳞片作为转化材料,利用农杆菌介导法,将蝴蝶兰F3′5′H基因导入百合Robina中。结果表明:以小鳞片为转化材料,预培养3d,OD_(600)为0.8,侵染10min,共培养3d,加入100μmol/L AS稳定转化率最高为12.78%;而以胚性愈伤为转化材料,预培养2d,OD_(600)为0.8,侵染10min,共培养3d,加入100μmol/L AS稳定转化率最高为12.22%。2种转化材料的最适潮霉素筛选浓度均为20mg/L。对抗性植株分别进行PCR和反转录PCR检测,获得9个阳性株系,Southern印记分析进一步确定了6株转基因百合中携带蓝色基因F3′5′H,为后续进一步获得蓝色百合奠定了基础。     

抗菌肽基因转化厚皮甜瓜的研究

以厚皮甜瓜FY1的子叶为试材,研究不同激素组合和配比对甜瓜植株再生的影响,并用农杆菌介导法将银杏抗菌肽基因Gnk2-1转化甜瓜。结果表明:(1)甜瓜子叶的最佳愈伤组织及不定芽诱导培养基为MS+2.0mg.L-1 6-BA+0.1mg.L-1 IAA,出愈率和出芽率均达95%以上;最佳芽伸长培养基为MS+0.2mg.L-1 KT;最佳生根培养基为1/2MS+0.1mg.L-1 IAA。(2)卡那霉素对甜瓜外植体的生长和分化有明显的抑制作用,适宜的筛选压力为100mg.L-1。(3)将子叶预培养2d,在农杆菌菌液浓度OD600值为0.5左右时,侵染外植体10min左右,共培养3d,转化效率最高。(4)经PCR鉴定获得了抗性植株,抗病性鉴定显示,转基因植株对枯萎病的抗性有所增强,发病迟缓。     

静息细胞转化生产3-羟基丙酸的条件优化

本文研究了静息细胞生物转化生产3-羟基丙酸的反应体系。考察了以甘油为底物,利用静息细胞转化生产3一羟基丙酸的相关因素,确定了最佳的转化条件：细胞浓度20g／L,甘油浓度20g／L,辅酶VB12浓度10mg／L,NAD＋浓度0．15mmol／L,温度35℃,反应体系为0．05mol／LpH7．0Tris—HCl缓冲液。在上述条件下反应6h后,3-羟基丙酸的产量达到为3．17g／L,底物转化率为28．33％。由上述结果可知,采用静息细胞转化法为3-HP的生物合成提供了一种可能的方法。     

EuFPS基因表达载体构建及对杜仲遗传转化的研究

本实验用EcoRⅠ和BamHⅠ双酶切植物表达载体pSH737和含有目的基因的pUC-FPS,定向连接得到重组质粒pSH-FPS,将其导入农杆菌EHA105.采用农杆菌介导法对杜仲进行遗传转化,研究了卡那霉素(kanamycin,Km)浓度、预培养时间、菌液浓度及侵染时间、乙酰丁香酮(acetosyringone,AS)浓度、共培养时间等对杜仲遗传转化效率的影响.结果表明,选择无菌苗苗龄15 d的杜仲下胚轴,卡那霉素浓度50mg/L,农杆菌浓度OD600值0.3-0.6,侵染时间8 min,侵染时菌体重悬液中添加50 μmol/L乙酰丁香酮,共培养时间3 d,抗性芽的获得率最高.对再生植株进行GUS检测发现有45%的植株呈阳性.     

雪花莲凝集素基因转化菊花及转基因植株的抗蚜性研究

针对菊花存在的蚜虫虫害问题,采用农杆菌介导法将gna基因导入菊花叶片,共获得93个转化克隆。研究了影响转化频率的主要因素,得出在使用pH5．6的YEB培养基,菌液浓度OD600=0．4,45日苗龄中部叶片预培养1d,共培养4d,共培养的培养基中加入0．5mg／L GA3的条件下可使转化频率提高到11．21％。PCR、实时荧光PCR检测结果表明,外源基因已整合到植物细胞基因组中。转化植株幼苗饲虫实验表明,不同转化克隆的抗蚜性差异较大,蚜口密度抑制率从10％—84％不等,平均蚜口密度抑制率为39．4％。转化植株叶片蛋白提取液对小鼠红细胞具有凝集作用。     

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.     

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.