抗冷冻蛋白基因(afp)转化大豆的研究

目的:通过农杆菌介导法遗传转化大豆。方法:通过热激法将质粒pCAAFP66导入根癌农杆菌菌株EHA105中获得含有抗冷冻蛋白基因(afp)及除草剂抗性筛选标记基因(bar)的农杆菌工程菌株;以大豆品种华春6号和马祖1号种子的下胚轴为外植体,经过农杆菌介导将抗冷冻蛋白基因导入大豆基因组中,在含有除草剂草丁膦(PPT)的培养基中筛选、并经过PCR鉴定获得大豆转化植株。结果:PPT的最佳筛选浓度为1.0mg/L,华春6号和马祖1号的阳性植株数分别为6株和2株,转化效率分别为3.70%和0.94%。结论:不同基因型大豆的转化率存在差异,抗冷冻蛋白基因成功遗传转化进大豆细胞中。     

农杆菌介导的玉米大斑病菌转化

采用玉米大斑病菌Exserohilum turcicum的无性菌丝作受体,建立了农杆菌Agrobacterium tumefaciens介导的转化方法。采用的载体为 pUR5750, 携有来源于质粒pAN71的潮霉素抗性选择标记。PCR分析表明T-DNA 插入到E. turcicum基因组中。     

根癌农杆菌介导的黑曲霉遗传转化体系的建立及优化

基于根癌农杆菌介导的遗传转化方法的独特优点,研究黑曲霉转化过程中各主要影响因素,建立高效的黑曲霉遗传转化方法。构建双元载体pBI-hph,通过电转导入农杆菌LBA4404中,以黑曲霉TCCC41056为受体菌株,利用潮霉素B基因作为筛选标记,对影响转化效率的孢子悬液的新鲜程度及浓度、农杆菌菌液浓度、共培养时间、共培养温度这五个条件进行分析,建立根癌农杆菌介导的黑曲霉遗传转化体系。实验结果表明,上述条件对黑曲霉的转化效率有较大的影响,通过优化,黑曲霉转化效率可达83个转化子/10⁷分生孢子;整合到黑曲霉基因组的外源基因可以稳定遗传,在转接10代后遗传性能仍保持稳定,并在众多转化子中筛选得到了糖化酶活力提高18%的黑曲霉突变株。根癌农杆菌介导的黑曲霉转化体系的建立,为进一步研究黑曲霉的功能基因以及开发黑曲霉表达系统提供了有力的手段。     

农杆菌介导的玉米遗传转化研究进展

农杆菌介导的转基因法是目前玉米遗传转化的主流方法之一。目前,模式玉米种质幼胚的转化体系已程式化,且开发了新筛选基因和获得不含筛选基因转基因玉米的方法,但是大多数育种骨干自交系转化频率低和转化受体基本上是幼胚。从农杆菌、受体及培养条件多方面各种因素对问题进行分析,多数研究认为针对特定基因型和受体材料建立好的受体再生系统,结合高效率农杆菌转化体系,获得多目的基因聚合(无其它外源片段)的转基因玉米将是农杆菌介导玉米转化体系研究的最终目标。本文主要从农杆菌介导(转基因)法应用于玉米遗传转化的历史、现状、问题等方面进行综述,为同领域的研究者提供一定的参考。     

转果聚糖蔗糖转移酶基因(Sac B)美丽胡枝子的获得

采用农杆菌介导的遗传转化方法,将来自枯草杆菌的果聚糖蔗糖转移酶基因(Sac B) 导入美丽胡枝子,以提高胡枝子抵御干旱胁迫和盐胁迫的能力。以美丽胡枝子子叶节为外植体,通过与含有植物双元表达载体pKP的农杆菌LBA4404 共培养,将Sac B 基因导入美丽胡枝子基因组。经卡那霉素筛选后,共获得62 株卡那霉素抗性植株。经PCR特异性扩增和PCR-Southern杂交,证明有5株再生植株基因组DNA 中整合了Sac B 基因。通过RT-PCR分析,结果表明SacB 基因均获得表达。经过200 mmol/L NaCl和5% PEG模拟胁迫,发现转基因植株美丽胡枝子中,可溶性糖含量在任何时候均高于未转化植株,并比对照拥有更高的抗干旱胁迫和盐胁迫能力。     

水稻白叶枯病广谱抗性基因Xa21导入两用不育系培矮64S

以克隆的Xa21基因为外源基因,成熟胚愈伤组织为转化受体,应用农杆菌介导法对水稻两用型核不育系培矮64S进行转化,获46株转基因植株。PCR和Southern分析结果表明,Xa21已整合到受体基因组。用稻白叶枯病病原菌(Xanthomonasoryzaepv.oryzae)菲律宾小种6号接种鉴定,结果表明大多数转基因植株获得了抗病性。已整合的Xa21基因能够稳定地遗传,在所检测转基因株系的T1代中,Xa21基因显示3:1的分离。     

农杆菌介导的玉米遗传转化研究进展

本文就农杆菌介导的玉米遗传转化的技术要点及原理等进行了综述,并对各种影响农杆菌转化玉米效率的关键因子包括农杆菌的菌株与载体、标记基因、受体材料的基因型、来源和发育状态以及组织培养的条件等进行了讨论。     

根癌农杆菌介导真菌遗传转化的研究及应用

根癌农杆菌介导转化法（Agrobacterium tumefaciens-mediated transformation,ATMT）具有转化效率高、遗传稳定、适用范围广等诸多优点,已成为真菌遗传转化研究中的强有力手段,在真菌基因资源开发、真菌性疾病研究和外源蛋白表达研究中发挥巨大作用。本文概述了根癌农杆菌转化法在真菌转化中的研究进展、技术优缺点、转化机制、实验方法和应用现状,着重介绍影响其转化效率的因素并对优化方法进行探讨,展望了该技术在真菌基因资源发掘、基因编辑等方面的应用前景,为今后真菌的遗传转化研究提供参考。     

根癌农杆菌介导的球毛壳菌遗传转化及T-DNA插入突变体的获得

根癌农杆菌介导的遗传转化系统是植物基因工程常用方法,目前已将这一转化系统应用到酵母、丝状真菌以及人类细胞的转化。利用这一转化系统,成功地实现了丝状真菌球毛壳菌（Chaetomium globosum）的遗传转化,转化率约为60～180个转化子/10.7个孢子 。通过对转化子的PCR检测和Southern 杂交分析表明,TDNA已整合进毛壳菌基因组中,而且在所检测的转化子中都是以单拷贝的形式整合,转化子都能够稳定遗传。根癌农杆菌介导的遗传转化具有转化率高、低拷贝、遗传稳定、操作简便等优点,因此有可能成为丝状真菌遗传转化和功能基因组研究的有力工具。     

农杆菌介导的大豆高频遗传转化

大豆(Glycinemax(L.)Merrill)遗传转化目前常用的两种方法为农杆菌介导的子叶节转化系统和基因枪介导的体细胞胚转化,但这两种转化系统都存在转化频率低、难于重复及依赖于特定的基因型等问题。为了提高农杆菌介导的大豆子叶节的转化频率,采用了一种基于bar基因作为筛选标记基因的固体-液体筛选系统,与农杆菌共培养3d的大豆子叶节在MS添加2mg/L6-BA和5mg/L的glufosinate的筛选培养基培养2周后,再转到含有0.01mg/LTDZ和2mg/Lglufosinate的液体培养基中筛选,并每周更换一次培养液。得到的再生芽首先经GUS分析为阳性后再转入生根培养基得到完整转化植株,然后通过Southern杂交分析证实外源基因整合到大豆基因组,转化植物含有1~2个基因拷贝数。该转化系统具有转化频率高、转化周期短以及不依赖于大豆基因型等优点,对影响该转化系统的一些因子进行了讨论。     

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.     

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     

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.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

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.     

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).