Characterization of relic DNA from barley genome

Summary High-molecular-weight relic DNA fraction can be electrophoretically separated from the bulk of barley DNA digested with different restriction enzymes. We have cloned and analyzed a population of relic DNA fragments. The majority of AluI-relic DNA clones contained barley simple sequence satellite DNA and other families of repetitive DNA. One of these families, designated HvRT, has been analyzed in detail. This family is composed of tandemly arranged 118-bp monomers and is present in 7 × 10⁵ copies in the barley genome. Clones representing the HvRT family were sequenced. HvRT repeats were found to contain high levels of methylated cytosine. The HvRT family was found in the genomes of H. vulgare, H. leporinum, H. murinum, H. jubatum, but not in H. marinum, H. geniculatum, and wheat. Different barley species and cultivars show restriction fragment length polymorphism with the HvRT probe. Chromosome-specific subfamilies of HvRT were found to be present on different barley chromosomes, providing the possibility of using the HvRT probe as a chromosome specific marker. HvRT fragments up to 810 kbp in length were resolved by pulsed field gel electrophoresis.     

串叶松香草的核型研究

串叶松香草Silphiura perfoliatum L.系菊科(Compositae)松香草属(SilphiumL.)多年生宿根草本植物,原产北美洲。1979年由中国科学院植物研究所北京植物园首次从朝鲜引进我国,1980年引种我所栽培,通过几年的试验观察表明:串叶松香草是一种高产、质优、适应性强的饲料作物,近年来,我省广泛发展和应用。据文献报     

人体基因组随机单拷贝顺序的分离及其在染色体上的定位

本文从构建杂种细胞14-7-1的基因组文库出发,用种特异的探针分离出含有人体基因组顺序的重组子,并进一步分析了其中13个克隆,得到8个单拷贝顺序。通过与已建立的杂种细胞克隆分布板杂交以及染色体的原位杂交方法,将1个单拷贝顺序FD11-1定位在11p11-q11上。由于已经报道在11号染色体上具有3个连锁群,它们分别位于11p15、11p13和11q13上,因此,FD11-1有可能为11号染色体连锁基因图的建立提供1个有意义的座位。     

Chromosome aberrations in workers of nuclear-power plants

The frequencies of chromosome aberrations in 135 workers from nuclear-power plants were compared with those in 135 age-matched controls. A total of 135,000 cells was scored. The frequencies of dicentric chromosome were 1.67 × 10⁻³ in the exposed group and 0.49 × 10⁻³ in the control group and those of chromosome-type deletion were 3.33 × 10⁻³ and 1.10 × 10⁻³, respectively. The frequencies of all types of chromosome aberrations in the exposed subjects were higher than those in the control group, but no significant trend of dose-dependent increase was observed when only the exposed group were considered. Poisson regression analysis, with both exposed and control included, showed that there was a significant association of chromosome aberration with radiation dose and the duration of work, but not with age, smoking habit and alcohol intake. It was also found that recent exposure to radiation, within the last 5 years, had contributed more to the observed chromosome aberration than earlier exposure.     

Transformation of the extremely thermoacidophilic archaeon Sulfolobus solfataricus via a self-spreading vector

Abstract The comparative chromosomal locations of polymeric β-fructosidase SUC genes have been determined by Southern blot hybridization with the SUC2 probe in 91 different strains of Saccharomyces cerevisiae . Most of the strains exhibited a single SUC2 gene, but in some strains two or three SUC genes were found. All Suc⁻ strains carried a silent suc2⁰ sequence. The accumulation of SUC genes was observed in populations derived from sources containing sucrose and seems to be absent in strains from sources promoting the MEL gene.     

抗癌药对黑胸大蠊淋巴细胞和生殖细胞核结构的损伤

噻替派浓度为0.1%、0.3%、0.5%时,黑胸大蠊精母细胞染色体断裂和裂隙率分别为6.3%、 10.5%和14.2%,显著地高于对卵母细胞的影响;和雄虫外周血淋巴细胞微核率呈平行关系,随微核率增多而增加。5-氟尿嘧啶浓度为0.1%、0.3%和0.5%时,卵母细胞染色体断裂和裂隙率分别为3.5%、9.8%和16.2%,和雌虫外周血淋巴细胞微核率呈平行关系,随微核率增多而增加,而对雄虫生殖细胞影响不显著。 Abstract:0.1%,0.3%,0.5% Thio-TEPA induced 6.3%,10.5% and 14.2% chromosome break or gap in spermatocyte of cockroach respectively.This was markedly higher than those in oocyte.In doses from 0.1 to 0.5 Tho-TEPA the frequency of micronucleus increased parallely with nuclear damage.0.1%,0.3%,0.5% 5-fluorouracil induced 3.5%,9.8%,16.2% chromosome break or gap in oocytes respectively.This was paralled with the frequency of micronucleus in lymphocytes of the female.5-fluorouracil showed not marked effect on spermatocyte.     

多胚水稻品系APⅣ的多卵遗传行为分析

通过多胚水稻品系APⅣ与单胚水稻品种IR36、明恢77和龙特浦B正反杂交, 研究APⅣ的多卵遗传行为,表明APⅣ的多卵性状可能不是由孢子体基因型决定的,而是由雄配子体基因型决定,属配子体遗传的范畴。 Abstract:The inheritance of poly-eggs was investigated by crossing and reciprocally crossing APIV with monoembryonic rice variety IR36,Minghui No.77 and Longtepu B,respectively.It was suggested that the production of poly-eggs is probably controlled by gametophytic genotypes,rather than sporophytic ones.     

Colchicine-mediated chromosome doubling during anther culture of maize (Zea mays L.)

Efficient methods of chromosome doubling are critical for the production of microspore-derived, doubled-haploid (=DH) plants, especially if, as in maize anther culture, spontaneous chromosome doubling occurs infrequently. In the present study, colchicine (5–1000 mg/l) was added to the induction medium and maize anthers were incubated in the colchicine-containing medium for different durations (1–7 days). In order to improve overall anther culture response, the culture temperature was adjusted to 14°C during the first 7 days. Colchicine applied at low concentration, i.e. 5 mg/l (7 days), or for short duration, i.e. 1–3 days (250 mg/l), showed beneficial effects on the formation of embryolike structures (=ES) and thus led to increased plant production, but was comparatively ineffective regarding chromosome doubling. Optimal doubling effects were observed when anthers had been exposed to culture medium containing 250 and 1000 mg/l of colchicine (7 days); in these treatments the doubling index (=DI), defined as the quotient of the number of DH plants and the number of totally regenerated plants in a specific treatment, rose to 0.56 and 0.53, respectively, compared to 0.20 in the untreated control. However, colchicine administered at concentrations higher than 250 mg/l seemed to be detrimental to general plant production; thus, in spite of a high DI, the overall DH plant production was even lower than in the control treatment. Maximum DH plant production for three different genotypes was accomplished with culture medium containing 250 mg/l of colchicine (7 days). With the best-responding genotype (ETH-M 36) a DH plant production of 9.9 DH plants/100 anthers was accomplished, i.e. a 7-fold increase compared to the non-treated anthers. This is the first report on efficient chromosome doubling in anther culture by subjecting anthers to colchicinecontaining induction medium during a post-plating cold treatment. Chromosome doubling as described here becomes an integral part of the maize anther culture protocol and thus represents a rapid and economical way to produce DH plants.     

Isolation and identification of Triticum aestivum L. em. Thell. cv Chinese Spring-T. peregrinum Hackel disomic chromosome addition lines

Analyses of RFLPs, isozymes, morphological markers and chromosome pairing were used to isolate 12 Triticum aestivum cv Chinese Spring (genomes A, B, and D)-T. peregrinum (genomes S^v and U^v) disomic chromosome addition lines. The evidence obtained indicates that each of the 12 lines contains an intact pair of T. peregrinum chromosomes. One monosomic addition line, believed to contain an intact 6S^v chromosome, was also isolated. A CS-7U^v chromosome addition line was not obtained. Syntenic relationships in common with the standard Triticeae arrangement were found for five of the seven S^v genome chromosomes. The exceptions were 4S^v and 7S^v. A reciprocal translocation exists between 4S¹ and 7S¹ in T. longissimum and evidence was obtained that the same translocation exists in T. peregrinum. In contrast, evidence for syntenic relationships in common with the standard Triticeae arrangements were found for only one U^v chromosome of T. peregrinum.; namely, chromosome 2U^v. All other U^v genome chromosomes are involved in at least one translocation, and the same translocations were found in the U genome of T. umbellulatum. Evidence was also obtained indicating that the centromeric regions of 4U and 4U^v are homoeologous to the centromeric regions of Triticeae homoeologous group-6 chromosomes, that the centromeric regions of 6U and 6U^v are homoeologous to the centromeric regions of group-4 chromosomes, and that 4U and 4U^v are more closely related overall to Triticeae homoeologous group-6 chromosomes than they are to group-4 chromosomes.     

大鼠肝癌模型CBRH—3的建立及其生物学特性

用ＤＥＮＡ诱发近交系Ｗｉｓｔａｒ大鼠,经三个月后得原发性肝癌,移植于同品系幼鼠,从而建立了 一株染色体众数正常,ＡＥＰ阳性的大鼠移植性肝癌模型,命名为ＣＢＲＨ－３,病理鉴定为肝细胞型肝 癌。至今已传至６０余代,目前生长稳定。