用聚合酶链式反应技术鉴定杂交稻种子纯度的初步研究

应用聚合酶链式反应（ＰＣＲ）技术,对３个杂交稻组合及其相应亲本的核ＤＮＡ进行了分析,筛选出９个随机扩增多态性ＤＮＡ（ＲＡＰＤ）随机引物和１对简单重复序列（ＳＳＲ）引物,可对供试材料进行真伪和纯度鉴定,该技术具有快速,简便,准确的特点,每人每天可测定１８０份样品,适用于杂交稻种子的商业化鉴定。     

Lutropin-choriogonadotropin receptor: an unusual member of the G protein-coupled receptor family

A complementary DNA (cDNA) for the rat luteal lutropin-choriogonadotropin receptor (LH-CG-R) was isolated with the use of a DNA probe generated in a polymerase chain reaction with oligonucleotide primers based on peptide sequences of purified receptor protein. As would be predicted from the cDNA sequence, the LH-CG-R consists of a 26-residue signal peptide, a 341-residue extracellular domain displaying an internal repeat structure characteristic of members of the leucine-rich glycoprotein (LRG) family, and a 333-residue region containing seven transmembrane segments. This membrane-spanning region displays sequence similarity with all members of the G protein-coupled receptor family. Hence, the LH-CG-R gene may have evolved by recombination of LRG and G protein-coupled receptor genes. Cells engineered to express LH-CG-R cDNA bind human choriogonadotropin with high affinity and show an increase in cyclic adenosine monophosphate when exposed to hormone. As revealed by RNA blot analysis and in situ hybridization, the 4.4-kilobase cognate messenger RNA is prominently localized in the rat ovary.     

Retroviral DNA integration directed by HIV integration protein in vitro

Efficient retroviral growth requires integration of a DNA copy of the viral RNA genome into a chromosome of the host. As a first step in analyzing the mechanism of integration of human immunodeficiency virus (HIV) DNA, a cell-free system was established that models the integration reaction. The in vitro system depends on the HIV integration (IN) protein, which was partially purified from insect cells engineered to express IN protein in large quantities. Integration was detected in a biological assay that scores the insertion of a linear DNA containing HIV terminal sequences into a lambda DNA target. Some integration products generated in this assay contained five-base pair duplications of the target DNA at the recombination junctions, a characteristic of HIV integration in vivo; the remaining products contained aberrant junctional sequences that may have been produced in a variation of the normal reaction. These results indicate that HIV IN protein is the only viral protein required to insert model HIV DNA sequences into a target DNA in vitro.     

dsRNA介导的抗ToMV和CMV植物表达载体的构建

[目的]构建通过表达dsRNA,诱导植物基因沉默机制可抗2种病毒的表达载体.[方法]根据已报道番茄花叶病毒(ToMV)的运动蛋白基因(MP)和黄瓜花叶病毒(CMV)的沉默抑制子基因(2b)的核苷酸序列设计特异性引物,扩增到部分△MP和2b基因;然后通过重组PCR技术将2个病毒基因进行融合,获得长度为676 bp的融合基因△MP-2b.再将融合基因以反向重复的方式与大豆内含子相连,并定向插入到植物表达载体pBIN438上35S启动子下游.[结果]构建了含两种不同病毒来源基因的植物表达载体pBIN438△MP-2b(i/r).酶切和PCR鉴定证明所构建的载体与预期的设计完全一致.[结论]为利用RNA沉默原理进行植物广谱抗病研究奠定了基础.     

Molecular cloning and expression of a human B-cell growth factor gene in Escherichia coli

A human B-cell growth factor (BCGF) (12 kilodaltons) supports the clonal proliferation of B lymphocytes. A clone was isolated that contained the proper structural sequence to encode biologically active, 12-kilodalton BCGF in Escherichia coli and to hybridize to a specific messenger RNA, identified by in vitro translation in Xenopus laevis oocytes. A relatively hydrophobic region of 18 amino acids was found at the amino terminal of the 124-amino acid-long polypeptide. The carboxyl terminal is composed of at least 32 amino acids that are derived from nucleotide sequences bearing significant homology to the Alu repeat family.     

High-resolution mapping of human chromosome 11 by in situ hybridization with cosmid clones

Cosmid clones containing human DNA inserts have been mapped on chromosome 11 by fluorescence in situ hybridization under conditions that suppress signal from repetitive DNA sequences. Thirteen known genes, one chromosome 11-specific DNA repeat, and 36 random clones were analyzed. High-resolution mapping was facilitated by using digital imaging microscopy and by analyzing extended (prometaphase) chromosomes. The map coordinates established by in situ hybridization showed a one to one correspondence with those determined by Southern (DNA) blot analysis of hybrid cell lines containing fragments of chromosome 11. Furthermore, by hybridizing three or more cosmids simultaneously, gene order on the chromosome could be established unequivocally. These results demonstrate the feasibility of rapidly producing high-resolution maps of human chromosomes by in situ hybridization.     

Human sarcomas contain RNA related to the RNA of a mouse leukemia virus

Labeled DNA complementary to the RNA of the Rauscher leukemia virus was hybridized with RNA from the polysome fraction of human sarcomas. Eighteen out of 25 specimens contained RNA possessing homology to the RNA of the mouse leukemia virus but not to that of the unrelated viruses causing mammary tumors in mice or myeloblastosis in chickens. Further, no normal adult or fetal tissues showed significant amounts of RNA specific to mouse leukemia virus. It appears that human sarcomas contain RNA sequences homologous to those found in an agent related to a virus known to cause sarcomas in mice.     

鸡传染性支气管炎病毒地高辛标记探针检测方法的的建立和应用

根据GenBank中已经发表的IBV N基因的保守序列,设计合成一对引物,利用RT-PCR技术扩增IBVN基因的582 bp的核酸片段,并制备出地高辛标记的IBV核酸探针。特异性检测结果表明,该探针能与不同毒株的IBV核酸发生特异性杂交,而与对照的NDV、鹅副粘病毒的核酸杂交反应为阴性;敏感性检测结果表明,该探针对IBV的最低检出量为10 pg,显示所制备的核酸探针用于IBV的检测是可行的。     

基于RAD-seq技术的金银花SSR标记开发及鉴定

[目的]通过开发特异性高的多态性分子标记位点,以弥补金银花在简单重复序列(SSR)标记方面的匮乏,推动金银花在遗传资源管理及良种鉴定等方向的研究,为后续全基因组测序及组装策略奠定基础.[方法]运用RAD-seq技术对2份金银花样品进行简化基因组测序,利用MISA软件识别contig上的SSR序列并对各类型序列特征进行归...     

柑橘栽培品种（系）DNA指纹图谱库的构建

 【目的】构建柑橘栽培品种（系）的DNA指纹图谱数据库,为建立柑橘种苗纯度及真实性鉴定技术体系和技术规范奠定基础。【方法】利用SSR标记和ISSR标记对102个柑橘栽培品种（系）进行DNA指纹分析,筛选适合的特征引物,构建柑橘栽培品种（系）的指纹图谱数据库。【结果】从200对SSR引物中筛选到重复性好、多态性丰富的12对引物作为柑橘品种（系）鉴定的特征引物,12对SSR特征引物组合可鉴别42个品种（系）;在此基础上,对未出现SSR特征指纹的60个品种（系）进行ISSR指纹分析,从40个ISSR引物中筛选到2个可用于品种鉴定的特征引物,结合SSR标记,可快速、准确地鉴别70个柑橘的品种（系）。并利用这12对SSR特征引物和2个ISSR特征引物构建了70个柑橘栽培品种（系）的DNA特征指纹图谱数据库。【结论】SSR和ISSR标记适于构建柑橘栽培品种DNA指纹图谱库;指纹图谱库的建立为柑橘种苗纯度及真实性鉴定奠定了基础。     

蒺藜苜蓿叶绿体微卫星分布规律的研究

利用已公布的蒺藜苜蓿(Medicao truntula)叶绿体DNA(cpDNA)全序列测序结果,应用生物信息学软件对蒺藜苜蓿微卫星位点的分布情况进行了统计分析,结果表明:在已公布的124 033 bp的蒺藜苜蓿叶绿体基因组序列中,共有341个SSR序列,SSR的碱基总数达3 987 bp,约占整个基因组的3.2%;在所有SSR序列中,数量最多的是单碱基SSR,数量达到297个,占总数的87.1%,其次是二碱基重复序列,占12.6%,三碱基微卫星序列最少,仅有1个,大于三碱基的微卫星数为0;在单碱基重复中又以A和T重复为主,占单碱基重复总数的84.5%,二碱基重复也以AT和TA为主,占95.5%,单碱基中的纯粹重复类型占总数的65.3%。研究结果为该物种的分子标记的筛选提供了基础信息。     

Rous sarcoma virus nucleotide sequences in cellular DNA: measurement by RNA-DNA hybridization

Kinetic analysis of the hybridization of 71S RNA from Prague strain of Rous sarcoma virus with an excess of DNA from virus induced sarcomas indicated the presence of the majority of the viral genome sequences in cellular DNA with a very low average frequency per cell. About one-third of the viral sequences were at least partially complementary to DNA sequences with a higher average frequency on the order of 50 to 100 per cell. Normal chick embryo DNA was distinctly different, but contained sequences at least partially homologous to some fraction of the viral RNA.     

甘肃省河西地区菜豆病毒病分子检测

以采集自甘肃省河西地区表现病毒病症状的菜豆病株叶组织总RNA为模板,进行RT-PCR扩增,鉴定出苜蓿花叶病毒、小西葫芦黄花叶病毒、菜叶普通花叶病毒、黑眼豇豆花叶病毒4种病毒.对预期大小的扩增产物进行直接测序.结果表明:该地区菜豆病毒病的发生以苜蓿花叶病毒、黑眼豇豆花叶病毒和小西葫芦黄花叶病毒复合侵染为主.     

ISSR分子标记在芦柑提纯复壮研究中的应用

采用ISSR(Inter-simple Sequence Repeat)分子标记技术,从随机引物中筛选出能稳定扩增的14条引物,利用2条引物对供试的10个芦柑样品进行PCR扩增,获得了与母本完全一致的条带,从而可以确定鉴定样本为珠心苗。     

Role for piRNAs and noncoding RNA in de novo DNA methylation of the imprinted mouse Rasgrf1 locus

Genomic imprinting causes parental origin-specific monoallelic gene expression through differential DNA methylation established in the parental germ line. However, the mechanisms underlying how specific sequences are selectively methylated are not fully understood. We have found that the components of the PIWI-interacting RNA (piRNA) pathway are required for de novo methylation of the differentially methylated region (DMR) of the imprinted mouse Rasgrf1 locus, but not other paternally imprinted loci. A retrotransposon sequence within a noncoding RNA spanning the DMR was targeted by piRNAs generated from a different locus. A direct repeat in the DMR, which is required for the methylation and imprinting of Rasgrf1, served as a promoter for this RNA. We propose a model in which piRNAs and a target RNA direct the sequence-specific methylation of Rasgrf1.     

利用SCAR-PCR检测杂交油菜"蜀杂9号"的杂种纯度

用两个分别能在“蜀杂9号”父、母本之间稳定产生多态性的随机引物S18和S31,对父、母本DNA样品进行RAPD扩增,将得到的特异标记片段S18750和S31550进行回收、克隆和测序。根据测序结果设计序列特异性扩增(SCAR)引物SZ9SP1和SZ9SP2,将“蜀杂9号”的亲本RAPD标记转化为序列特异的SCAR标记。当用两对引物分别扩增杂种F1代单株总DNA时,能分别获得父、母本特异序列扩增带,表明获得的SCAR标记能可靠地用于“蜀杂9号”杂种纯度的检测。