农杆菌介导Bt基因遗传转化高粱

高粱是全球仅次于小麦、水稻、玉米、大豆和马铃薯等的重要作物之一。以高粱幼穗愈伤组织为转化受体,通过农杆菌介导法和含有抗潮霉素和gus基因的双元载体将杀虫晶体蛋白基因cry1Ab导入高粱品种115、ICS21B和5-27,经Hyg筛选共获得21个独立的转基因株系,52株转基因植株,平均转化率为1.9%。经PCR、Southern杂交和RT-PCR分析表明cry1Ab基因已整合入高粱基因组中并得到正确转录。Bt蛋白Westernblotting分析和ELISA定量测定显示,cry1Ab基因在转基因高粱植株中表达,但不同转基因植株表达量有差异。饲虫试验表明,转基因高粱对大螟(Sesamiainferens)具有一定抗性。     

转cry1Ab基因抗虫水稻的田间试验

采用农杆菌介导的遗传转化技术, 将Bt基因cry1Ab导入三系恢复系明恢63获得了一批抗虫性及农艺性状较好的转基因纯合株系。研究中, 进一步检测了这些纯合株系的拷贝数、Bt蛋白含量、抗虫性及主要农艺性状。结果显示: 5个转基因纯合株系均为单拷贝; 纯合株系T_1Ab-10及其杂种的Bt蛋白含量最高; 人工接虫和自然感虫试验中, T_1Ab-10对二化螟、三化螟和稻纵卷叶螟均表现高度抗性; 喷药试验中, 阳性植株与阴性植株、对照植株的主要农艺性状均没有显著差异。这说明转cry1Ab基因纯合株系T_1Ab-10具商品化潜力, 可作基因聚合材料。     

转基因水稻cry1Ab/Ac基因及蛋白在肉鸡肠道中的残留检测

旨在研究转基因水稻对饲喂肉鸡的影响,以含有转cry1Ab/Ac基因水稻的饲料饲喂肉鸡,分析了肉鸡空肠、回肠、盲肠、直肠中cry1Ab/Ac基因和蛋白残留情况,并用体外实验验证了外源基因的降解情况。结果表明,饲喂转cry1Ab/Ac基因水稻21 d和42 d的肉鸡肠道4个部位中没有检测到cry1Ab/Ac基因残留,体外消化外源基因的实验发现外源基因在肉鸡肠道中约4 h后开始逐步降解。对上述4个部位内容物进行ELISA和Western blot分析,均未检测到Cry1Ab/Ac蛋白残留。综合分析表明,转基因水稻中的外源基因和蛋白在肉鸡肠道中易被消化和降解。     

转修饰cry1Ac基因籼稻明恢81经花药培养获得抗虫DH系

对基因枪法获得的明恢81转修饰的cry1Ac基因当代植株进行花药培养,共接种花药2600枚,获得83份花培植株,其中双倍体植株43份,单倍体植株40份,PCR结果表明含有cry1Ac基因的植株55份,花培植株群体中转基因与非转基因植株的比值为2：1（55／28）,进一步结合Southern blot和ELISA分析,于花培植株当代筛选到转基因纯合株系36份,外源蛋白表达量上,花药来源于同一克隆的DH系的不同植株之间基本一致,最高的Cry1Ac含量达0．25％,田间抗虫性试验表明,经花药培养纯合获得的部分转基因纯合系植株对二化螟（chilo suppressalis)表现出高抗,而且主要农艺性状保持不变,以上结果表明水稻花药培养可以加速转基因的纯合与良种利用。     

转反义蜡质基因‘湘晴’及其杂交稻米的直链淀粉含量研究

利用根癌农杆菌介导将反义蜡质基因(anti-Waxy)导入三系恢复系湘晴水稻获得转基因植株.从T1代外源基因呈单拷贝整合的转基因湘晴水稻中选取3个稻米直链淀粉含量降低较明显的单株继续种植得到纯合后代.以纯合转基因植株及湘晴水稻(对照)为恢复系分别与寒丰不育系杂交,获得4组杂交稻后代(F2).3个T3代纯合转基因湘晴水稻糙米(T4)直链淀粉含量分别为14.42%、13.96%和14.72%,对照为16.04%;3组由转基因湘晴水稻为父本杂交制种后代(F2)糙米直链淀粉含量分别为14.53%、13.77%和14.64%,对照杂交稻(F2)为16.22%.研究表明,导入湘晴水稻中的反义蜡质基因不仅能够降低湘晴稻米直链淀粉含量,还能够进一步抑制杂交后代的稻米直链淀粉合成.     

利用竞争性PCR筛选无标记Xa21转基因水稻

PCR是一种简单、迅速、灵敏的检测方法,但假阳性与假阴性却影响了它在常规应用中的准确性。本研究利用竞争性PCR解决无标记Xa21转基因水稻PCR检测中的假阳性与假阴性问题。标记基因潮霉素基因(Hygromycin phosphotransferase,hpt)的竞争模板是外加的日本晴hpt转基因植株基因组DNA,抗白叶枯病基因Xa21的竞争模板是待测水稻内源的位于第11染色体上的Xa21同源基因序列。利用这一方法对双右边界T-DNA载体转化产生的转基因T1代植株进行分析,可以有效地减少或排除假阳性或假阴性样品,选出真正的转基因阳性植株。与常规PCR相比竞争性PCR提高了无标记Xa21转基因植株筛选的准确性。对获得的无标记Xa21转基因植株进行白叶枯抗病鉴定与潮霉素抗性鉴定证实了该方法的可靠性。     

饲喂Bt水稻的褐家鼠肠道中cry1Ab/Ac基因和蛋白的残留检测北大核心CSCD

分别用含有转cry1Ab/Ac基因水稻和亲本水稻的饲料饲喂野生褐家鼠,旨在检测外源cry1Ab/Ac基因和蛋白在褐家鼠雌鼠雄鼠空肠、回肠、盲肠中的残留情况。检测结果显示,饲喂转基因水稻50 d和110 d的雌雄褐家鼠肠道3个部位中没有检测到cry1Ab/Ac基因残留,在体外消化实验中过量外源基因全长及片段在4 h后开始逐步降解,约12 h全部降解。3个肠道部位提取的蛋白进行ELISA和Western blot分析,结果显示肠道内容物中无Cry1Ab/Ac蛋白残留。因此外源基因和蛋白不会在饲喂了转基因水稻的野生褐家鼠肠道中残留。     

饲喂Bt水稻的褐家鼠肠道中cry1Ab/Ac基因和蛋白的残留检测

分别用含有转cry1Ab/Ac基因水稻和亲本水稻的饲料饲喂野生褐家鼠,旨在检测外源cry1Ab/Ac基因和蛋白在褐家鼠雌鼠雄鼠空肠、回肠、盲肠中的残留情况。检测结果显示,饲喂转基因水稻50 d和110 d的雌雄褐家鼠肠道3个部位中没有检测到cry1Ab/Ac基因残留,在体外消化实验中过量外源基因全长及片段在4 h后开始逐步降解,约12 h全部降解。3个肠道部位提取的蛋白进行ELISA和Western blot分析,结果显示肠道内容物中无Cry1Ab/Ac蛋白残留。因此外源基因和蛋白不会在饲喂了转基因水稻的野生褐家鼠肠道中残留。     

转cry1Ac＋cry2Ab基因棉与转cry1Ac＋剧咯邢基因棉荒地的生存竞争能力

【背景】此研究为“十二五”转基因生物新品种培育国家项目中创建新的转基因棉花品种环境安全评价技术而设。【方法】以转双价双成抗虫基因（cry1Ac＋cry2Ab）棉和转双价抗虫、抗除草剂基因（cry1Ac＋肼强阳）棉为观察品种,非转基因棉赣棉11号为对照品种,在荒地用撒播和3cm深度播种2种方式,于2011年5月一2012年3月对棉花出苗率、株高、生育进程、棉吐絮瓣数、絮瓣脱落率、自生苗等生存竞争能力进行比较,检测、评价其杂草化的风险,并探讨、验证检测技术的可行性。【结果】在荒地条件下,以2种方式播种的转cry1Ac＋cry2Ab基因棉和转cry1Ac＋EP5P5基因棉与非转基因棉相比,上述各项指标的竞争能力总体上未表现显著优势。【结论与意义】转cry1Ac＋cry2Ab基因棉和转cry1Ac＋EPSPS基因棉在荒地条件下生长无杂草化风险。同时,研究证明,在荒地自然生态条件下,可以采用撒播和3cm深度播种方法检测新的转基因棉花品种在生存竞争能力上的杂草化风险,在测评上有互为参照效应,为定性评价新的转基因棉花品种的杂草化风险提供了保障。     

转cry1Ab/cry1Ac基因水稻对大螟幼虫的取食、生长及存活的影响

本文采用活体生测的方法测定了转cry1Ab/cry1Ac基因水稻对大螟Sesamia inferens(Walker)幼虫的取食、生长以及存活的影响。结果表明,以转cry1Ab/cry1Ac基因水稻为食的大螟3龄和5龄幼虫的累计取食量和相对摄食率与对照相比都显著的减少。取食转Bt水稻后,大螟3龄和5龄幼虫体重均出现负增长。随着取食转基因水稻时间的延长,大螟3龄幼虫的校正死亡率可以达到100%,5龄幼虫的校正死亡率达到85%。     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

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.