根癌农杆菌介导转录因子CBF1基因对草莓的转化

以草莓(Fragaria ananassa Duch)品种“达斯莱克特“(Darselect)为试材,用根癌农杆菌介导的方法,将转录因子CBF1基因导入草莓叶盘细胞,经多次筛选获得了转基因植株.转化植株经PCR检测,证实了CBF1基因已经整合到草莓的基因组中.以电解质渗透法检测了植株的抗寒性,结果显示转基因草莓的抗寒能力较未转化植株有明显提高,且不同转基因株系之间提高程度有着差异.     

通过农杆菌介导将番茄铁转运蛋白基因导入八棱海棠

用农杆菌介导法,成功地将番茄铁转运蛋白基因导入了苹果砧木八棱海棠.获得了19个卡那霉素抗性株系,其中有11个株系经PCR鉴定为阳性.Southern杂交结果显示:有9个转基因株系基因组中整合了完整的目的基因.选择其中含有单拷贝和3个拷贝目的基因的各一个株系进行水培试验,结果表明整合了单拷贝目的基因的转基因株系表现出较强的抗缺铁胁迫能力,5周后其植株的鲜重比对照高21%～34%.     

转基因油菜后代的农艺性状表现及其抗虫性研究

以农杆菌介导法转几丁质酶基因和蝎毒蛋白基因的晋4和H165油菜种子为试材.采用PCR检测、农艺性状调查、田间抗虫鉴定等技术,对转基因植株及其后代进行了选育研究.T1、T2和T3代材料的PCR检测结果显示目的基因在转基因植株及其后代中可稳定遗传;抗虫鉴定结果证明转基因油菜植株的抗虫性得到提高,转基因株系的被害率、被害程度明显小于相应对照,转基因株系中菜粉蝶幼虫的存活率低于对照,而且存活虫的发育进程比对照缓慢;农艺性状调查结果证实,转基因手段对油菜植株的角果数、角粒数和千粒重等性状没有太大影响.根据上述结果,在T3代时,筛选得到J5-1、J5-2、H5-1和H11-1四个纯合的转基因油菜株系.     

小黑杨花药培养植株转化胆碱氧化酶基因提高耐盐性

以小黑杨(Populus simonii ×P. nigra)花药培养植株无菌苗叶片为外植体, 通过根癌农杆菌(Agrob acteriumtumefaciens)介导法将胆碱氧化酶基因(codA)导入小黑杨中, 共获得4株转化株系, PCR扩增和Southern杂交检测结果全部 呈阳性, 表明codA基因已整合到小黑杨花药培养植株基因组中。荧光定量RT-PCR检测证明, codA基因在小黑杨花药培养植株中获得表达。耐盐实验结果显示, 各转基因株系在0.6%的NaCl浓度下能够生长, 而非转基因对照小黑杨受盐害严重, 说明codA基因的导入提高了转基因植株的耐盐性。     

通过转重复结构的ACC氧化酶基因延长香石竹的瓶插期

以香石竹叶片为外植体,用农杆菌(Agrobacteriumtumefaciens)介导法,在选择分化培养基中培养后,将香石竹重复结构的ACC氧化酶(ACO)基因核DNA导入香石竹‘Maber品种.经Southera杂交检测,证明外源基因已整合到香石竹基因组,共获得3株转化植株.转基因植株在隔离条件下栽培时正常开花,转基因T257株系切花衰老过程中乙烯释放量较对照低95%,没有乙烯跃变峰出现.在25℃条件下比较瓶插期,有2个转化株系瓶插期显著延长,最长比对照长了5 d以上.     

马铃薯块茎特异性启动子驱动的人白细胞介素-12的遗传转化研究

为获得高效表达人白细胞介素-12(h IL-12)蛋白的转基因马铃薯植株,利用根瘤农杆菌侵染法将前期构建的马铃薯块茎特异性启动子Ppatatin驱动的h IL-12植物表达载体导入马铃薯,通过共培养、筛选、分化等过程获得转基因植株,并结合PCR、RT-PCR、GUS染色及ELISA分析对转基因植株进行鉴定。结果显示,获得12个马铃薯转基因株系,PCR检测表明其中的10个株系目的基因已导入马铃薯基因组,转基因阳性率为83%;RT-PCR分析表明其中的7个株系外源基因在转录水平成功获得表达,ELISA分析表明其中的5个株系有明显的蛋白水平表达。对这7个株系后代的检测表明外源基因成功表达且具有良好的遗传稳定性。     

cryIAc基因在转基因玉米中的遗传规律及对抗虫性影响

旨在研究目的基因在转基因植株和后代植株(株系)中的遗传规律及其对转化植株抗虫性的影响。以花粉介导法将cryIAc基因导入玉米自交系‘郑58’和‘昌7-2’,对转化植株及其后代株系进行分子检测和田间抗虫鉴定。结果表明:(1)转化‘郑58’和‘昌7-2’,T1代分别获得转基因植株24和41个,转化率高达20%以上;(2)转基因T2代、杂交F2代及回交1代(B1)的分子检测结果证明,外源基因的遗传符合孟德尔的3∶1、3∶1和1∶1的遗传分离规律;(3)连续多带的分子检测结果还表明,外源基因可稳定遗传并有效表达,表达水平在9.8-14.3 ng/g叶片鲜重之间;(4)抗虫鉴定结果显示,在阴性对照全部感虫情形下,转基因纯合株系仍表现出较高抗虫活性;(5)此外,回交试验结果还证明外源基因通过杂交可传递给下一代;(6)最终经筛选得到SZ003、SZ005、SC001、SC004和SC007五个高抗虫转基因株系。结果表明,花粉介导法是一种高效、快捷的转化方法,cryIAc基因导入玉米自交系植株后赋予和提高了转基因植株的抗虫活性。     

脱水应答转录因子CBF1的克隆与转基因小麦的分子检测

根据已发表的小麦(T.aestivum)转录因子CBF1基因序列(GenBank Accession No.AF376136),设计引物从小麦品种‘京花1号’叶片中克隆出该基因,用拟南芥RD29B基因为启动子构建含CBF1基因的逆境诱导表达载体pBAC127F(6 967 bp),以‘99-92’、‘5-98’、‘104’和‘轮选987’等冬小麦品种(系)的幼穗和幼胚为材料,基因枪转化该表达载体。经筛选与植株再生,共获得14株转基因植株及其后代株系。这14个株系经PCR分析和点杂交检测,最终确认了5-98-40、5-98-41这2个株系为转基因株系,结果表明拟南芥RD29B启动子调控下的转录因子CBF1基因已稳定整合到转基因植株中。     

过量表达大叶补血草LgNHX1基因对拟南芥耐盐性的影响

利用植物表达载体pCAMBIA1301和农杆菌GV3101将LgNHX1(全长1 656 bp)基因在拟南芥中过量表达.在含30 mg/L潮霉素的培养基上筛选获得LgNHX1的纯合转化子,并对其进行了分子鉴定和耐盐性分析.结果显示,经PCR和RT-PCR鉴定,野生型植株(对照)没有出现扩增条带,而转基因株系有相应的扩增条带,表明LgNHX1的确已经整合到拟南芥的基因组中,并已正常转录.在不同盐浓度处理下,转基因株系生长情况好于野生型对照;转基因植株地上部分和根的干重、鲜重相对高于野生型对照,但差异没有达到显著水平;当盐浓度达到150-200 mmol/L时,两个特基因株系的Na+含量显著高于野生型,K+含量极显著高于野生型.以上结果表明,过量表达LgNHX1基因可能增强了拟南芥将Na+区隔化至液泡的能力,提高了转基因拟南芥的耐盐能力.     

转基因玉米中目的基因的遗传表达及其抗病性研究

采用花粉介导方法将几丁质酶基因和潮霉素基因导入玉米(Zea maysL.)自交系海92-1中,以筛选抗玉米丝黑穗病的转基因品种.对转化植株及其后代植株的PCR、Southern blot检测表明,目的基因已导入转化植株并整合到其基因组中,且能够稳定遗传.ELISA分析证明转基因植株中目的基因可高效表达,表达产物量在9.8~16.3 ng?g-1鲜叶左右.统计分析显示,目的基因产物表达水平与转基因植株的抗病性呈极显著正相关(r=0.925,P<0.01).接种病毒鉴定结果揭示转基因株系的抗病性比对照提高3~4级.结合农艺性状筛选,选育到401、403这2个抗丝黑穗病且其它农艺性状优良的转基因纯合株系.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.