Mapping of Murine Fibroblast Growth Factor Receptors Refines Regions of Homology between Mouse and Human Chromosomes

The genes for the fibroblast growth factor receptors Fgfr2, Fgfr3, and Fgfr4 have been mapped in the mouse using an interspecific backcross mapping panel. The Fgfr loci map to previously defined regions of homology between human and mouse chromosomes and provide additional information regarding human/mouse comparative mapping.     

Nuclear and chloroplast transformation inChlamydomonas reinhardtii: strategies for genetic manipulation and gene expression

Transformation of the nuclear, chloroplast, and mitochondrial genomes can now be accomplished inChlamydomonas reinhardtii. Many biosynthetic pathways are carried out in the chloroplast, and efforts to manipulate these pathways will require that gene products be directed to this compartment. Chloroplast proteins are encoded in either the chloroplast or nuclear genome. In the latter case they are synthesized in the cytoplasm and imported post-translationally into the chloroplast. Thus, strategies for expressing foreign genes or overexpressing endogenous genes whose products reside in the chloroplast could involve either genome. This paper reviews the present status of transformation methodology for the nuclear and chloroplast genomes inChlamydomonas. Considerations for expressing gene products in the chloroplast are discussed. Experimental evidence for homologous recombination during transformation of the nuclear genome is presented.     

陕西省常见蜜源植物花粉形态的研究

运用扫描电子显微镜,对陕西省境内３０种常见蜜源植物的花粉粒进行了观察研究,描述了花粉粒的大小、萌发孔类型及其表面纹饰等形态特征。结果表明：绝大多数种的蜜源植物,其花粉粒的形态特征明显不同。本文还就花粉粒形态特征,在鉴定蜜源植物花粉的属种,确定蜂蜜的产地、评价蜂蜜的品质等方面进行了探讨。     

江西忍冬属药用植物资源

报道了江西忍冬属药用植物种类、地理分布、临床疗效、化学成分等有关情况,对该属资源的开发利用提出了合理建议。     

γ射线诱发大鼠胚胎细胞转化与N－ras的激活

以γ射线诱发转化的大鼠胚胎细胞(REC:myc:γ33)的DNA构建粘粒基因库,用总基因库DNA转染NIH/3T3细胞,产生转化灶的DNA作二轮转染,二轮转化的NIH/3T3细胞内有大鼠REC:myc:γ33DNA中具转化活性的N-ras基因,用不对称PCR和DNA序列分析法证明,REC:myc:γ33细胞中鼠N-ras的活化是由于第61位密码子的A→G点突变.NIH/3T3转化灶中鼠N-ras也有同样点突变,但NIH/3T3细胞的内源性N-ras基因则无此突变.     

沈阳西部污灌水中有机污染物的分析

沈阳西部污灌水中有机污染物的分析刘海玲,张丽珊,姚家彪,于殿臣,朱岩,可夫,姜萍（中国科学院沈阳应用生态研究所,１１００１５）ＡｎａｌｙｓｉｓｏｆＯｒｇａｎｉｃＰｏｌｌｕｔａｎｔｓｉｎＩｒｒｉｇａｔｅｄｓｅｗａｇｅＩｎＷｅｓｔｅｒｎＳｈｅｎｙａｎｇ．...     

Analysis of the frequency of inheritance of transposed Ds elements in Arabidopsis after activation by a CaMV 35S promoter fusion to the Ac transposase gene

The Ac/Ds transposon system of maize shows low activity in Arabidopsis. However, fusion of the CaMV 35S promoter to the transposase gene (35S::TPase) increases the abundance of the single Ac mRNA encoded by Ac and increases the frequency of Ds excision. In the experiments reported here it is examined whether this high excision frequency is associated with efficient re-insertion of the transposon. This was measured by using a Ds that carried a hygromycin resistance gene (HPT) and was inserted within a streptomycin resistance gene (SPT). Excision of Ds therefore gives rise to streptomycin resistance, while hygromycin resistance is associated with the presence of a transposed Ds or with retention of the element at its original location. Self-fertilisation of most individuals heterozygous for Ds and 35S::TPase produced many streptomycin-resistant (strep^r) progeny, but in many of these families a small proportion of strep^r seedlings were also resistant to hygromycin (hyg^r). Nevertheless, 70% of families tested did give rise to at least one strep^r, hyg^r seedling, and over 90% of these individuals carried a transposed Ds. In contrast, the Ac promoter fusion to the transposase gene (Ac::TPase) produced fewer strep^rhyg^r progeny, and only 53% of these carried a transposed Ds. However, a higher proportion of the strep^r seedlings were also hyg^r than after activation by 35S::TPase. We also examined the genotype of strep^r, hyg^r seedlings and demonstrated that after activation by 35S::TPase many of these were homozygous for the transposed Ds, while this did not occur after activation by Ac::TPase. From these and other data we conclude that excisions driven by 35S::TPase usually occur prior to floral development, and that although a low proportion of strep^r progeny plants inherit a transposed Ds, those that do can be efficiently selected with an antibiotic resistance gene contained within the element. Our data have important implications for transposon tagging strategies in transgenic plants and these are discussed.