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891.
Yao-Jun Chang Yu-Fen Cao Jin-Mei Zhang Lu-Ming Tian Xing-Guang Dong Ying Zhang Dan Qi Xiao-shuang Zhang 《Tree Genetics & Genomes》2017,13(2):44
Eight pairs of chloroplast DNA (cpDNA) universal primers selected from 34 pairs were used to assess the genetic diversity of 132 pear accessions in Northern China. Among them, six amplified cpDNA fragments showed genetic diversity. A total of 24 variable sites, including 1 singleton variable site and 23 parsimony informative sites, as well as 21 insertion-deletion fragments, were obtained from the combined cpDNA sequences (5309–5535 bp). Two trnL-trnF-487 haplotypes, five trnL-trnF-413 haplotypes, five rbcL haplotypes, six trnS-psbC haplotypes, eight accD-psaI haplotypes and 12 rps16-trnQ haplotypes were identified among the individuals. Twenty-one haplotypes were identified based on the combined fragments. The values of nucleotide diversity (Pi), average number of nucleotide differences (k) and haplotype diversity (Hd) were 0.00070, 3.56408 and 0.7960, respectively. No statistical significance was detected in Tajima’s D test. Remarkably, the important cpDNA haplotypes and their representing accessions were identified clearly in this study. H_19 was considered as one of the ancient haplotypes and was a divergent centre. H_16 was the most common haplotype of the wild accessions. H_2 was the haplotype representing the most pear germplasm resources (46 cultivars and two wild Ussurian Pear accessions), followed by haplotype H_5 (30 cultivars, two wild Ussurian Pear accessions and four sand pears in outgroups) representing the cultivars ‘Dangshan Suli’ and ‘Yali’, which harbour the largest and the second largest cultivation areas in China. More importantly, this study demonstrated, for the first time, the supposed evolution routes of Pyrus based on cpDNA divergence in the background of pear phylogeny in Northern China. 相似文献
892.
大鼠脊髓细胞膜胰岛素受体的结合特性 总被引:3,自引:0,他引:3
大鼠脊髓细胞膜胰岛素受体的结合特性朱尚权,徐明华,张新堂,叶莺(中国科学院上海生物化学研究所,200031)姜新建,林淑琼(上海市第一人民医院康复科,200085)关键词胰岛素受体,脊髓细胞膜免疫组织化学、放射免疫自显影和放射受体测定技术已证明脑各区... 相似文献
893.
894.
云南普通马矮型马蛋白多态性及其品种分化关系 总被引:2,自引:1,他引:2
本文运用蛋白电泳技术对来自云南省文山州马关县和麻栗坡县的21匹普通马和14匹矮型马进行了分析。共分析遗传座位44个,其中有10个座位检测到多态性。根据分子钟假说和相应的公式,推算两者的分歧时间约为18.5万年。 相似文献
895.
应用CTB基因启动子及信号肽序列构建分泌性表达系统 总被引:1,自引:0,他引:1
利用霍乱毒素B亚基基因的启动子、信号肽序列及ctx操纵子的转录终止信号构建了分泌性表达的质粒载体pMCOSS。Β-半乳糖苷酶基因克隆至霍乱毒素B亚基基因的信号肽序列下游后能得到高效分泌性表达。不同的宿主菌和培养基成分中对β-半乳糖苷酶的表达产量有较大的影响,以MM2为宿主菌、在玉米浆培养基中β-半乳糖苷酶的表达产量达4 lOOu/ml,产物的大部分分泌至细胞的周质,活力测定的结果与SDS—PAGE电泳测定结果基本一致,说明表达的β-半乳糖苷酶绝大部分都具有酶活性。构建的蛋白质分泌性表达的载体-宿主系统及合适的培养条件为易形成包含体的蛋白质的高效表达提供了一条新的途径。 相似文献
896.
The ars operon of Escherichia coli confers arsenical and antimonial resistance. 总被引:2,自引:2,他引:2 下载免费PDF全文
The chromosomally encoded arsenical resistance (ars) operon subcloned into a multicopy plasmid was found to confer a moderate level of resistance to arsenite and antimonite in Escherichia coli. When the operon was deleted from the chromosome, the cells exhibited hypersensitivity to arsenite, antimonite, and arsenate. Expression of the ars genes was inducible by arsenite. By Southern hybridization, the operon was found in all strains of E. coli examined but not in Salmonella typhimurium, Pseudomonas aeruginosa, or Bacillus subtilis. 相似文献
897.
898.
899.
Reversal of multidrug resistance of vincristine-resistant gastric adenocarcinoma cells through up-regulation of DARPP-32 总被引:1,自引:0,他引:1
Hong L Wang J Han Y Zhao Y Gao J Wang J Han Y Zhang X Yan L Zhou X Qiao T Chen Z Fan D 《Cell biology international》2007,31(9):1010-1015
Here we investigated the roles of DARPP-32 in multidrug resistance (MDR) of gastric cancer cells and the possible underlying mechanisms. We constructed the eukaryotic expression vector of DARPP-32 and transfected it into human vincristine-resistant gastric adenocarcinoma cell line SGC7901/VCR. Up-regulation of DARPP-32 could significantly enhance the sensitivity of SGC7901/VCR cells towards vincristine, adriamycin, 5-fluorouracil and cisplatin, and could decrease the capacity of cells to efflux adriamycin. What's more, the results of subrenal capsule assay confirmed that DARPP-32 might play a certain role in MDR of gastric cancer. DARPP-32 could significantly down-regulate the expression of P-gp and zinc ribbon domain-containing 1 (ZNRD1), but not alter the expression of multidrug resistance-associated protein (MRP) or the glutathione S-transferase (GST). DARPP-32 could also significantly decrease the anti-apoptotic activity of SGC7901/VCR cells. Further study of the biological functions of DARPP-32 might be helpful for understanding the mechanisms of MDR in gastric cancer. 相似文献
900.
Liu Y Li GP White KL Rickords LF Sessions BR Aston KI Bunch TD 《Molecular reproduction and development》2007,74(11):1473-1482
The effects of nicotine on nuclear maturation and meiotic spindle dynamics of bovine oocytes and subsequent embryonic development were investigated. Maturation rates (85%-94%) derived from nicotine treatments at 0.01 to 1.0 mM were similar to the control (86%), but significantly decreased at 2.0 to 6.0 mM. Haploid complements of metaphase II oocytes in 0.01 to 1.0 mM nicotine (approximately 90%) were similar to the control, while lower (ranged from 63% to 76%, P < 0.05 or P < 0.01) haploid oocytes were observed in the 2.0 to 6.0 mM nicotine groups. The majority of the PB1-free oocytes derived from 3.0 to 6.0 mM nicotine treatments were diploidy (2n = 60). Spindle microtubules changed from characteristically being asymmetrical in the controls to being equally distributed into two separate chromosome groups in the nicotine treatments. Nicotine disorganized the microfilament organization and inhibited the movement of anaphase or telophase chromosomes to the cortical area. The inhibited two chromosome groups became two spindles that either moved close in proximity or merged entirely together resulting in diploidy within the affected oocyte. Nicotine treatment significantly reduced the rate of cleavage and blastocyst development after parthenogenetic activation. Diploidy and cell number were drastically reduced in the resultant blastocysts. In conclusion, nicotine can alter the normal process of bovine oocyte meiosis and affects subsequent embryonic development. 相似文献