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71.
利用COS7细胞暂时表达系统,研究转译起始序列对EPO-cDNA表达的影响。通过DNA重组技术,构建了原EPO-cDNA表达载体pCSV-EPO(1),其转译起始序列为5'AATTCATGG3'。同时通过定点突变技术,将起始序列改变成5'CCACCATGG3',而构建了另一表达载体PCSV-EPO(2)。后经序列分析证明无误后和前均通过DEAE-dextran法转染COS7细胞上清,测定结果为 相似文献
72.
Renu Tuteja Narendra Tuteja Franco Lilliu Bruno Bembi Renzo Galanello Antonio Cao Francisco E. Baralle 《Human genetics》1994,94(3):314-315
We report a novel mutation in exon 9 of the glucocerebrosidase gene of a patient with Gaucher disease and of Sardinian origin. 相似文献
73.
The use of PCR to monitor the population abundance of six human intestinal bacterial species in an in vitro semicontinuous culture system 总被引:2,自引:0,他引:2
Rong-Fu Wang Wei-Wen Cao Warren L. Campbell Latrina Hairston Wirt Franklin Carl E. Cerniglia 《FEMS microbiology letters》1994,124(2):229-237
Abstract Six PCR primer sets complementary to the 16S rDNAs (rRNA genes) were developed and shown to be specific for the following anaerobic bacteria: Clostridium clostridiiforme, C. perfringens, C. leptum, Bacteroides vulgatus, B. distasonis , and B. thetaiotaomicron , respectively. These primers were used for PCR to detect and monitor the bacteria in a semicontinuous culture system designed to mimic intestinal microflora in the human gastrointestinal tract. Except for C. perfringens , the five species of Bacteroides and Clostridia present in the in vitro culture system were detected by the PCR, and the titers varied from 10−2 to 10−6 dilutions. The role of azo dye reduction by these bacterial species in the system was examined and discussed. 相似文献
74.
Chunyu Cao Hisao Kurazono Shinji Yamasaki Keiko Kashiwagi Kazuei Igarashi Yoshifumi Takeda 《Microbiology and immunology》1994,38(6):441-447
The gene encoding a Verotoxin 2 variant, VTvp1, was mutated by oligonucleotide-directed site-specific mutagenesis. Among 6 mutant toxins encoded by the mutated genes, E167Q-R170L (glutamic acid at position 167 and arginine at position 170 from N-terminus of the A subunit were replaced by glutamine and leucine, respectively) was found to have markedly decreased activities; inhibition of protein synthesis, Vero cell cytotoxicity and mouse lethality of the purified E167Q-R170L were 1/1,900, 1/125,000 and 1/2,000, respectively, of those of the purified wild-type VT2vp1. Since the antigenic property of the E167Q-R170L was demonstrated to be similar to that of the wild-type VT2vp1 by Ouchterlony double gel diffusion test and by neutralization test of Vero cell cytotoxicity of the VT2vp1, a possibility to use the mutant VT2vp1, E167Q-R170L, as a toxoid is discussed. 相似文献
75.
三褶脉紫菀中的新二萜甙 总被引:1,自引:0,他引:1
三褶脉紫菀(AsterageratoidesTurcz.)系菊科多年生草本植物,遍布全国,是民间常用的中药,有清热解毒、祛痰镇咳的功效[1,2]。化学工作者们曾从其同属植物紫菀(AstertararicusL.f.)中分离到紫菀酮(shionone)、槲皮素(quercetin)、无羁萜(friedelin)、表无羁萜(epifriedelinel)、毛叶醇(lachnophyllol)、乙酸毛叶酯(lachnophyllolacetate)、茴香醚(anethole)以及紫菀三萜皂甙[2—4]… 相似文献
76.
77.
Phylogenetic place of guinea pigs: no support of the rodent-polyphyly hypothesis from maximum-likelihood analyses of multiple protein sequences 总被引:3,自引:2,他引:1
Graur et al.'s (1991) hypothesis that the guinea pig-like rodents have an
evolutionary origin within mammals that is separate from that of other
rodents (the rodent-polyphyly hypothesis) was reexamined by the
maximum-likelihood method for protein phylogeny, as well as by the
maximum-parsimony and neighbor-joining methods. The overall evidence does
not support Graur et al.'s hypothesis, which radically contradicts the
traditional view of rodent monophyly. This work demonstrates that we must
be careful in choosing a proper method for phylogenetic inference and that
an argument based on a small data set (with respect to the length of the
sequence and especially the number of species) may be unstable.
相似文献
78.
79.
Cao Thi Manh Evelyne Bismuth Jean-Pierre Boutin Madeleine Provot Marie-Louise Champigny 《Physiologia plantarum》1993,89(3):460-466
It has been demonstrated previously that field pea (Pisum sativum L. cv. Express) grown in hydroponic culture on a complete nutrient solution with low NH4+ concentrations (<0.5 mM) will produce a larger than normal proliferation of nodules. Peas grown in the absence of mineral N in hydroponic culture have been shown to rapidly autoregulate nodulation, forming a static nodule number by 14 to 21 days after planting. The present study further characterizes the effect of NH4+ concentration in hydroponic culture on nodulation and nodule growth. Peas were grown continually for 4 weeks at NH4+ concentrations that were autoregulatory (0.0 mM), stimulatory (0.2 mM) or inhibitory (1.0 mM), or peas were transferred between autoregulatory or NH4+ inhibited and stimulatory solutions after 2 weeks. The peas nodulated as expected when grown under constant autoregulatory, stimulatory or inhibitory concentrations of NH4+. When peas were transferred from the inhibitory (1.0 mM) to the stimulatory solution (0.2 mM) a massive proliferation of nodule primordia over the entire root system was observed within 3 days of the transfer. When they were transferred from the autoregulatory (0.0 mM) to the stimulatory (0.2 mM) solution a 10-day delay occurred before a proliferation in nodule primordia occurred at distal regions of the root system. These findings support our hypothesis that low concentrations (<1.0 mM) of NH4+ in hydroponic culture cause a suppression of autoregulation in pea. In addition, the temporal and spatial differences in nodule proliferation between transfer treatments demonstrate at a whole plant level that autoregulation and NH4+ inhibition suppress early nodule development via different mechanisms. 相似文献
80.
本文研究了长白落叶松(LarixolgensisHenry)大小孢子叶球的分化及其分布规律.获得如下结果:(1)6月下旬芽鳞形成期终止,7月初进入小孢子叶分化期,7月未至8月上旬小孢子叶分化期结束.8月上旬进入小孢子囊分化期,8月下旬出现造孢细胞,9月中旬形成小孢子母细胞.10月底小孢子母细胞保持在细线期阶段,小孢子叶球进入冬季休眠期.(2)9月初苞片原基开始形成,9月中旬珠鳞原基形成;10月上旬出现胚珠原始体,10月下旬大孢子母细胞形成,10月底大孢子叶球芽进入冬季休眠.(3)小孢子叶球芽主要分布在树冠的中、下部.数量上远远大于大孢子叶球芽的数量,约为大孢子叶球芽的19倍。大孢子叶球芽主要集中分布在树冠中部,而且树冠下部多于树冠上部。 相似文献