Positive control of transformed phenotype in hybrids between SV40-transformed and normal human cells

Somatic cell hybrids have been obtained between SV40-transformed Lesch-Nyhan fibroblasts, which are deficient in hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and display glucose-6-phosphate dehydrogenase A (G6PD-A) activity, and late-passage HGPRT-positive W138 human embryo fibroblasts, which display G6PD-B activity. The human-human hybrid clones, which display G6PD-A and G6PD-B and heteropolymers of the two enzyme forms, have the same growth characteristic as the SV40-transformed parental cells and behave as continuous cell lines. The SV40 tumor antigen, the gene for which has been assigned to human chromosome 7, is present in all clones examined.     

Epstein-Barr virus: detection of genome in somatic cell hybrids of Burkitt lymphoblastoid cells

Somatic cell hybrids of Burkitt lymphoblastoid cells, from which Epstein-Barr virus can be recovered, were examined for the presence of virus DNA by DNA-RNA hybridization. Four clones of hybrid cells, each negative for virus antigens by immunofluorescence, contained virus DNA in varying genomic equivalents. The number of virus genome equivalents increased in the hybrid cells after induction of virus with iododeoxyuridine.     

Mixed leukocyte stimulation of normal peripheral leukocytes by autologous lymphoblastoid cells

Lymphocyte culture lines can be established by using buffy coat cells from normal or diseased individuals. Established lymphocytoblasts from a normal donor were used in the one-way mixed leukocyte culture test and were found to stimulate the peripheral lymphocytes of that donor. These lymphocytoblasts were also capable of stimulating allogeneic lymphocyte populations.     

Hybridization of Burkitt lymphoblastoid cells

Burkitt lymphoblastoid cell lines have been fused to mouse and human cell lines with the use of inactivated Sendai virus. The heterokaryons have developed into somatic cell hybrids of both parental cell types. Chromosome analyses confirm that cells now growing in selective medium are hybrids. Initial observations of preparations of the hybrid cells reveal that 5'-iododeoxyuridine can induce continued synthesis of Epstein-Barr virus antigens by these hybrid cells.     

Mucus secretion-stimulating activity in human lymphoblastoid cells

Two fractions isolated from cultured lymphoblastoid cells stimulated mucus secretion from the urn cell complex of the marine invertebrate Sipunculus nudus. The activity detected in the nuclear fraction was trypsin-sensitive, and it increased in response to specific nucleotides.     

Participation of c-myc protein in DNA synthesis of human cells

The protein product of oncogene c-myc is believed to be important in regulation of the cell cycle. However, its direct role in DNA synthesis has not been explored. Experiments presented here show that the addition of affinity-purified antibodies against the human c-myc protein to nuclei isolated from several types of human cells reversibly inhibited DNA synthesis and DNA polymerase activity of these nuclei. This suggests that c-myc encodes a protein that is functionally involved in DNA synthesis.     

甜瓜亲本与其F1代的RAPD标记分析

利用RAPD标记方法,从分子水平上探测了甜瓜亲本与其杂种F1的遗传差异,用27个引物对11个甜瓜基因型进行了扩增,共扩增出44条有效谱带,其中多态性条带19条,占总条带数的43.18%。每条引物可扩增3～8条带,平均每条引物产生1.63条有效带。根据RAPD遗传距离进行分析,杂种F1多偏向母本自交系遗传;甜瓜亲本自交系间的遗传距离为0～0.39。作为父本,TopMark自交系与H16自交系相比,子代更多继承了Top-Mark自交系的遗传特性。以上结果与田间性状表现相符,RAPD标记用于甜瓜遗传差异的研究切实可行,其结果可用于育种过程中的亲本选配和分子标记辅助选择。     

三系杂交稻与其亲本粒重的关系研究

为了探明水稻杂种一代与其亲本千粒重的遗传关系,为大粒型杂交组合选育提供参考依据,选用粒重有明显差异的三系不育系和恢复系进行杂交配组,对15个杂交组合的杂种一代与其亲本千粒重进行相关同归分析.结果表明:1)所有组合的杂种一代千粒重普遍超过其双亲平均值,均亲优势率2.0%-5.7%,除2个组合的超亲优势率是负值,其余组合都表现一定程度的正向超亲优势;2)父母本的千粒重与杂种一代的千粒重相关达极显著水平;3)父母本与杂种一代千粒重的标准偏回归系数分别为0.426和0.624,母本千粒重对杂种一代的影响较大.     

豇豆与饭豆种间杂种的获得及其鉴定

对豇豆和饭豆进行种间杂交试验,30个正反交组合中有3个杂交组合获得种子,它们分别是豇豆A65×饭豆B24、豇豆A27×饭豆D1、豇豆A136×饭豆A163。对获得的种间杂种及其双亲进行表型性状、生理指标及分子标记鉴定分析结果表明,豇豆A136×饭豆A163杂交组合所获杂种为假杂种,其他2个杂交组合所获杂种为真杂种。利用豇豆与饭豆种间杂交将饭豆的有利性状基因导入豇豆中,拓宽豇豆的遗传背景,为豇豆种质资源的创新与新品种选育提供基础。     

Recognition by human V gamma 9/V delta 2 T cells of a GroEL homolog on Daudi Burkitt's lymphoma cells

All human gamma delta T cells coexpressing the products of the variable (V) region T cell receptor (TCR) gene segments V gamma 9 and V delta 2 recognize antigens from mycobacterial extracts and Daudi cells. Exogenous and endogenous ligands on the cell surface, homologous to the groEL heat shock family, induced reactivities that resembled superantigen responses in this major subset of human peripheral blood gamma delta T cells. Stimulation of human V gamma 9/V delta 2 T cells is not restricted by human leukocyte antigens (HLA), including nonpolymorphic beta 2-microglobulin (beta 2M)-associated class Ib molecules. These data may be important for understanding the role of gamma delta T cells in autoimmunity and in responses to microorganisms and tumors.     

水稻籼粳交亲籼型不育系的杂种优势利用

采用珍汕97B/秀水13的后代为材料,通过回交转育,育成系列亲籼型不育系.以Ⅱ-32A为对照,按8×6不完全双列杂交,分析各不育系产量性状的遗传效应与杂种优势,评价其育种价值.结果表明:(1)产量主要性状大多受加性效应和显性效应共同控制.单株重是一个复杂性状,受显性效应控制.株高、总粒数、生育期和有效穗与结实率的表型、遗传、加性和显性相关均呈负显著或极显著相关,育种上应注意上述性状的选择,提高后代结实率.(2)株高、主穗长、粒重及生育期的狭义遗传力较高,早期选择有效;而单株重、有效穗、总粒数及结实率的狭义遗传率低,分离世代长,需高世代鉴定.(3)42个籼粳交F1中有18个组合结实率高于80%,16个组合单株重超过Ⅱ优63,杂种优势表现在单株重、株高、穗粒数等性状.     

Metabolic differences between normal and neoplastic cells: effects of aminonucleoside on cytoplasmic messenger RNA

Treatment of cultured normal human fibroblasts with an adenosine analog (aminonucleoside of puromycin) rapidly inhibits the appearance of cytoplasmic messenger RNA, identified by its polyadenylate sequence. Similar treatment of SV40-transformed fibroblasts does not lead to such an inhibition. Cordycepin. another analog of adenosine. inlhibits polyadenylate-containing cytoplasmic RNA in both types of cell.     

苦荞过敏原TBa和TBb基因的共表达及其包涵体复性的研究

[研究目的]利用大肠杆菌共表达苦荞过敏蛋白的两个亚基,并对表达产物进行包涵体复性研究和免疫学活性分析;[方法]用已构建的表达质pET-28a-TBa和pET-32m-TBb,共转化大肠杆菌BL21(DE3)感受态,利用双抗生素筛选法,获得稳定遗传的双质粒转化子,经IPTG诱导,两个基因在同一宿主菌中共表达,在共表达产物复性过程中,两个亚基互为分子伴侣,相互促进了蛋白质的重新正确折叠;[结果]表迭蛋白以包涵体的形式存在,ELISA检测表明:复性后的蛋白免疫学活性得到了提高;[结论]由此获得了有活性的蛋白质,并且建立了不相容双质粒共表达外源基因和包涵体复性的方法.