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21.
孙毅 《科技情报开发与经济》2005,15(19):170-171
简要介绍了生命科学研究的新突破,包括人类嗅觉谜团被解开,激活自愈机能治疗肝炎,运用基因重组或剔除基因治疗癌症获重大进展等. 相似文献
22.
Zhi-Hui Su Munehiro Okamoto Osamu Tominaga Katsumi Akita Noboru Kashiwai Y?ki Imura Tooru Ojika Yoshiyuki Nagahata Syozo Osawa 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2006,82(7):232-250
An approach to deduce the mechanism of stabilization of the hybrid-derived populations in the Ohomopterus ground beetles has been made by comparative studies on the phylogenetic trees of the mitochondrial and nuclear DNA. A phylogenetic tree based on the internal transcribed spacer (ITS) of nuclear ribosomal gene roughly reflects the relations of morphological species group, while mitochondrial NADH dehydrogenase subunit 5 (ND5) gene shows a considerable different topology on the tree; there exist several geographically-linked lineages, most of which consist of more than one species. These results suggest that the replacement of mitochondria has occurred widely in the Ohomopterus species. In most cases, hybridization is unidirectional, i.e., the species A (♂) hybridized with another species B (♀) and not vice versa, with accompanied replacement of mitochondria of A by those of B. The results also suggest that partial or complete occupation of the distribution territory by a hybrid-derived morphological species. The morphological appearance of the resultant hybrid-derivatives are recognized as that of the original species A. Emergence of a morphological new species from a hybrid-derived population has been exemplified. 相似文献
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Expression of foreign genes transferred into mammalian cells by electroporation has been studied. The pX1TK gene, pSV2Neo gene and pUCEJ oncogene have been introduced into MLTK-cells and NIH/3T3 cells, respectively. Stable transformation transient expression of TK gene by MLTK-cells as well as stable and malignant transformation of NIH/3T3 cells have been obtained. Transient expression frequency is about 80% and stable transformation frequency is about 10~(-4). Integration of foreign genes into the cellular genome was verified with molecular hybridization. Tumor development was observed after inoculation of transformed celts into nude mice. 相似文献
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Bergquist Peter L. Te’o V. S. Junior Gibbs Moreland D. Cziferszky Angela C. E. De Faria Fabricia P. Azevedo Maristela O. Nevalainen K. M. Helena 《Applied biochemistry and biotechnology》2002,98(1-9):165-176
Cost-effective production of enzymes for industrial processes makes the appropriate selection of the host-vector expression
system critical. We have developed two systems for the bulk production of bleaching enzymes from thermophiles. Kluyveromyces lactis has been developed as a secretion host employing expression vectors based on the 2μ-like plasmid pKD1 of Kluyveromyces drosophilarium. Our second system involves the filamentous fungus Trichoderma reesei. Fusion and nonfusion vectors have been constructed using the strong cellobiohydrolase 1 (cbh1) promoter. The KEX2 protease cleavage site and a 6 × HIS-tag have been incorporated to facilitate both cleavage and purification
of the mature foreign proteins. 相似文献
27.
聚类是芯片数据分析中被广泛使用的方法。未知基因的功能通常通过其与已知基因在不同生物状态下具有表达相似性来进行预测。然而,还未有人就这种通过表达相似性来进行功能注释的方法的可靠性进行评估。本文利用Gene Ontology对表达相似性和基因功能相似性的相关关系进行了全面的研究。研究表明,尽管表达谱的相似性和基因功能相似性之间有一定的依赖关系,但相关性较弱。在Gene Ontology的三大类中,相对生物过程和分子功能,基因表达谱的相似性更有助于细胞组分的注释。本文的研究结果对于基因功能的预测有一定的指导意义。 相似文献
28.
Youngwon Lee Charles P. Emerson Myoung Hee Kim 《Applied biochemistry and biotechnology》1995,55(3):231-240
TnINEO fusion gene was constructed by fusing 3.4-kbp of quailTnI genomic DNA sequences spanning the promoter to exon 5 and aneo gene in frame. A myoblast cell line was established after transfection of pTnINEO. Since this cell line was passaged several
times, a high frequency of neomycin (G418) sensitivity conversion was detected. Two drug-resistant variants were analyzed
through genomic Southern blot and S1 nuclease protection assay. One variant has a mutation(s) in the regulatory element that
activated the dormantTnI promoter-enhancer in myoblast, and the other has shown the genomic rearrangement. This result presented the possibility of
isolating factor(s) that activate the muscle-specificTnI promoter simply by screening drug-resistant cells having appropriate mutations. 相似文献
29.
Using the total human/mouse DNA as the probe, screening has been carried out three times with in situ plaque hybridization to obtain the single-copy DNA sequence from the human X chromosome genomic library. The effective rate of screening is 1. 45%. DNAs from clones containing single-copy inserts have been analyzed by a panel of hybrid cells with or without human X chromosome. Three segments, designated by DXFD52,73,75, are mapped to the X chromosome. DXFD52 has been precisely localized on Xq12-q13 with in situ chromosomal hybridization. DXFD52 has been partially sequenced. The results indicate that DXFD52 is a new isolated single-copy segment on the X chromosome. Great progress in the RFLPs study with DXFD52 has been achieved in the population of Chongqing, Sichuan Province. The results show that the DXFD52 can be used to detect the RFLP with Hind Ⅲ, Bgl Ⅱ, and Hinf Ⅰ. DXFD52 will be a potential "landmark" for the construction of the complete linkage map of human genome and the analysis of genomic s 相似文献
30.
以满江红鱼腥藻(Aac)提取总DNA为模板,通过PCR技术,扩增得到其谷氨酰胺合成酶基因(glnA)上游区.经酶切得到409bp的片段,并将其连接到pBluescriptⅡks+上测序.将测序结果与Anabaena7120调控序列比较,有982%的同源性.在上游调控中也具有niflike和E.colilike启动子,值得注意的是,调节蛋白VF1的结合位点正好位于niflike启动子上.所克隆的片段不但对蓝藻固氮、泌氨的基因调控研究具有意义,也对表达载体的构建具有实用价值. 相似文献