农杆菌介导的枳壳转化系统建立研究初报

以枳壳为对象 ,进行了农杆菌介导的上胚轴转化系统建立研究 ,得到了携带柑桔衰退病病毒外壳蛋白基因的枳壳转化植株。研究表明 :枳壳各类外植体中 ,上胚轴是较好的转化材料 ;上胚轴出芽部位主要在形态学上端。以卡那霉素为选择剂 ,外植体水平面放置时 ,选择剂的剂量是 50～ 70mg/ L。转化研究中发现感染液中乙酰丁香酮 10 0μmol/ L的加入促进转化外植体 Gus表达阳性率的提高。延迟 1a的选择培养 ,有助于 Gus阳性芽的增多。所得 Gus阳性无性系经 Southern blot杂交检测 ,证明外源基因已稳定整合到了植物基因组中 ,所得 Gus阳性植株确为携带柑桔衰退病病毒外壳蛋白基因的转化植株     

转小鼠金属硫蛋白cDNA枸杞的获得及其检测

小鼠金属硫蛋白－ＩｃＤＮＡ通过根癌农杆菌介导转枸杞,枸杞体内的表达产物对重金属镉有一定的抗性。用带有嵌合ｍＭＴ－ＩｃＤＮＡ及Ｃａ ＭＶ３５ｓ启动子的含非致瘤性Ｔｉ持粒载体的根癌农杆菌ＬＢＡ４４０４感染枸杞幼茎外植体,在含有卡那霉素１００μｇ／ｍＬ和５０μｍｏｌ／Ｌ Ｃｄ＾２＋的选择培养基上筛选转化的愈伤组织,并在含卡那霉素５０μｇ／ｍＬ和１００μｍｏｌ／Ｌ,Ｃｄ＾２＋的分化培养基上得到再生小芽。     

亚麻下胚轴离体培养和转化的研究

报道了亚麻（Ｌｉｎｕｍ　ｕｓｉｔａｔｉｓｓｉｍｕｍ）的高频率植株再生和细胞转化。亚麻下胚轴切段培养在ＭＳＢ分化培养基上,诱导分化出不定芽。最佳的激素组合是ＢＡ２ｍｇ／Ｌ＋ＩＡＡ０．５ｍｇ／Ｌ,分化频率可达９７％。在附加ＢＡ１ｍｇ／Ｌ和ＮＡＡ０．０２ｍｇ／Ｌ的ＭＳＢ培养基上,亚麻下胚轴外植体的不定芽分化频率也可达９０％以上。用根癌农杆菌（Ａｇｒｏｈａｃｔｅｒｉｕｍ　ｔｕｍｅｆａｃｉｅｎｓ）感染亚麻下胚轴外植体,在含卡那霉素５０ｍｇ／Ｌ的选择培养基上筛选获得卡那霉素抗性苗,并检测到ＧＵＳ基因活性表达。表明它们是转化植株,转化频率约为２％。     

根癌农杆菌对甘蓝型油菜的转化及转基因植株的再生

用根癌农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ ｔｕｍ ｅｆａｃｉｅｎｓ）共培养法把外源基因导入甘蓝型油菜（Ｂｒａｓｓｉ－ｃａ ｎａｐｕｓＬ．）主要栽培品种“云北２ 号”,获得转基因植株。所用外植体为带有１—２ ｍ ｍ 子叶柄的完整子叶,根癌农杆菌为Ａ２０８ＳＥ（ｐＴｉＴ３７－ＳＥ, ｐＲＯＡ９３）。Ｔｉ质粒ｐＲＯＡ９３ 带有ＮＰＴⅡ及ＧＵＳ嵌合基因。共培养２ 天后转到附加２５ ｍ ｇ／Ｌ卡那霉素的分化培养基（ＭＳ＋ ４．５ ｍ ｇ／ＬＢＡＰ）上。ＡｇＮＯ３ 和羧苄青霉素促进芽的分化,头孢霉素则有抑制作用。最高转化频率为２７％ 。把分化出的茎芽切下,插入含有２５ ｍ ｇ／Ｌ卡那霉素的生根培养基中。羧苄青霉素不利于根的形成。把完整抗性植株移入盛土壤的盆中,生长状况良好。测定β－葡糖苷酸酶活性,８４％ 明显高于对照。以ＮＰＴⅡ基因作探针进行Ｓｏｕｔｈｅｒｎ ｂｌｏｔ分析,证实外源基因已插入到植物细胞基因组中     

紫云英细胞转化条件的研究

研究了紫云英（ＡｓｔｒａｇａｌｕｓｓｉｎｉｃｕｓＬ．）细胞遗传转化的条件。根癌农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍｔｕｍ ｅｆａｃｉｅｎｓ）经含乙酰丁香酮的低ｐＨ／ＰＯ３－４ 诱导培养后,用来感染紫云英下胚轴原生质体,随后的细胞ＧＵＳ瞬间表达活性显著提高,间接证明了上述预培养诱导活化了细菌ｖｉｒ基因,促进了Ｔ－ＤＮＡ 向植物细胞转移。在ＰＥＧ介导的ＤＮＡ 转移中,较高的ｐＨ 和Ｃａ２＋ 浓度能够提高细胞ＧＵＳ活性。质粒ＤＮＡ 浓度及启动子类型对外源基因在植物细胞内表达也有一定影响。采用外植体－农杆菌共培养法,获得ＧＵＳ和ＮＰＴ Ⅱ基因稳定表达的紫云英转化植株     

影响农杆菌介导的大豆子叶节遗传转化的因素

利用携带pCAMBIA1301质粒（含hpt和gus基因）的超毒根癌农杆菌菌株EHA105对大豆子叶节外植体进行遗传转化,研究了影响农杆菌介导的大豆子叶节遗传转化的因素。研究结果表明．农杆菌侵染液和共培养培养基中添加200μmok/L乙酰丁香酮和50mg／L抗坏血酸可以有效促进农杆菌对大豆子叶节的转化。农杆菌与子叶节共培养后羧苄青霉素（250mr／L）和头孢霉素（100mg／L）结合使用能有效抑制农杆菌过度繁殖并提高转化芽诱导频率;在转化细胞的分化和转化芽伸长过程中,改进的筛选策略可以明显改善对转化芽的筛选效果,从而提高转化频率。应用优化后的转化体系．获得了3个国内大豆主栽品种的转基因植株,PCR阳性植株频率为3．8％～7．6％。转化植株叶片总DNA的PCR和Southern blot实验表明,T-DNA上的外源基因已经整合到大豆基因组中。     

双价外壳蛋白基因植物表达载体的构建及马铃薯转基因植株的鉴定

在克隆了马铃薯Ｘ病毒（ＰＶＸ）、马铃薯Ｙ 病毒（ＰＶＹ）和马铃薯卷叶病毒（ＰＬＲＶ）的外壳蛋白基因的基础上,构建同时包含ＰＶＸ和ＰＶＹ 与ＰＶＹ 和ＰＬＲＶ 两个外壳蛋白基因植物表达框架的表达载体,通过农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ ｔｕｍｅｆａｃｉｅｎｓ）介导转化烟草（Ｎｉｃｏｔｉａｎａｔａｂａｃｕｍ ）和生产上常用的几个马铃薯（Ｓｏｌａｎｕｍ ｔｕｂｅｒｏｓｕｍ ）优良品种：“Ｆａｖｏｒｉｔａ”、“虎头”、“克４”。经ＰＣＲ检测证明外源基因已整合到植物的染色体上,得到批量转基因植株。在转ＰＶＸ＋ＰＶＹ 外壳蛋白基因的烟草上接种ＰＶＸ （５ μｇ／ｍ Ｌ）、ＰＶＹ（２０ μｇ／ｍ Ｌ）病毒,得到有一定抗性的植株     

大球母贝精子介导外源基因转移研究

将大球母贝（Ｐｉｎｃｔａｄａ ｍａｘｉｍａ Ｊａｍｅｓｏｎ）精子与“全鱼”ＧＨ基因重组体ｐＣＡｇｃＧＨ和ｐＣＡｇｃＧＨｃ的线性ＤＮＡ混合,温育３０ｍｉｎ,经６次、２＾７、１０ｋＶ脉冲电处理后,与卵子受精,得到若干贝苗。从贝苗中提取ＤＮＡ,经ＰＣＲ扩增和Ｓｏｕｔｈｅｒｎ ｂｌｏｔ分子杂交表明,部分受体带有外源基因,当与精子温育的外源基因浓度分别为２μｇ／ｍＬ,６μｇ／ｍＬ及１８μｇ／ｍＬ时,相应贝苗     

石防风原生质体遗传转化及抗除草剂植株的再生

以石防风（Ｐｅｕｃｅｄａｎｕｍｔｅｒｅｂｉｎｔｈａｃｅｕｍ（Ｆｉｓｃｈ．）Ｆｉｓｃｈ．ｅｘＴｕｒｃｚ．）叶柄愈伤组织为材料建立以致密细胞团为主的悬浮培养物,用酶解法获得原生质体。用ＰＥＧ法将拟南芥菜（Ａｒａｂｉｄｏｐｓｉｓｔｈａｌｉａｎａ（Ｌ．）Ｈｅｙｎｈ．）抗除草剂基因导入原生质体后进行液体浅层培养。转化细胞经除草剂ｃｈｌｏｒｓｕｌｆｕｒｏｎ筛选,通过胚状体途径产生抗性小植株。转化处理１０６个原生质体,以加入４０～５０μｇ／ｍＬ质粒ＤＮＡ,ＰＥＧ终浓度为１０％,于１ｍＬ转化介质中,２６℃黑暗下处理２０ｍｉｎ的效果最好。ｃｔＤＮＡ的加入对转化结果无明显影响。分子杂交试验表明,突变的ａｌｓ基因已整合进转化植株的基因组中。转基因植株的细胞在脱分化过程中仍具有抗ｃｈｌｏｒｓｕｌｆｕｒｏｎ的能力;移栽成活的转基因小苗仍表现出抗除草剂特性,而未转化的植株在低浓度除草剂下即逐渐死亡。表明转入的ａｌｓ基因在石防风细胞内能够稳定表达。     

电脉冲法转化苏云金芽孢杆菌BMB171的研究

研究了用电脉冲法转化苏云金芽孢杆菌受体菌ＢＭＢ１７１的优化条件以及由转化导入的几类ｃｒｙ基因在ＢＭＢ１７１中的表达效果。结果表明,采用ＳＧ溶液作电脉冲缓冲液,用１０．ｏｋＶ／ｃｍ的脉冲场强和１次电脉冲（４．６ｍｓ）以及采用对数前期（ＯＤ_６５０ｎｍ为０．２～０．３）收获的受体菌,可以达到最高转化频率,其中用ｐＨＴ３１０１电转化 ＢＭＢ１７１的最高频率达 ８×１０７转化子／μｇ ＤＮＡ。转化频率随质粒ｐＨＴ３１０１浓度的增加,在５４．６９ｐｇ／ｍＬ至３．５０μｇ／ｍＬ范围内     

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.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various