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1.
为了研究鱼生长激素基因在大肠杆菌中的表达,采用聚合酶链反应（ＰＣＲ）技术对鲑鱼生长激素ｃＤＮＡ的５端和３端进行定向修饰．将修饰后的三种基因分别克隆到大肠杆菌表达质粒ｐＢＶ２２０,构建成重组鲑鱼生长激素表达质粒ｐＢＶＧＨ１１,ｐＢＶＧＨ１８和ｐＢＶＧＨ２４,转化大肠杆菌ＤＨ５α进行诱导表达．结果表明：核糖核蛋白体结合位点（ＳＤ）与起始密码子ＡＴＧ之间的距离对生长激素的表达水平影响极大．鲑鱼生长激素基因的终止密码子ＴＡＧ不能有效终止该基因在大肠杆菌中翻译的进行,造成部分通读．加入大肠杆菌强终止子ＴＡＡ可避免通读和产生超长蛋白,提高表达产量 相似文献
2.
利用大肠杆菌获取重组蛋白的研究进展 总被引：3，自引：0，他引：3
大肠杆菌是重组蛋白生产的首选体系，它能够以融合蛋白、非融合蛋白、包含体、蛋白分泌等几种方式生产重组蛋白，按照这几种方式，综述了最近几年利用大肠杆菌生产重组蛋白的研究进展． 相似文献
3.
刘顿 《中学课程辅导(初二版)》2007,(5):41-42
《数据的分析》这部分知识体现的数学思想有：
一、统计思想
例1 从鱼塘打捞草鱼240尾，从中任选9尾，称得每尾的质量分别是1．5，1．6，1．4，1．6，1．2，1．7，1．8，1．3，1．4（单位：kg），估计这240尾草鱼的总质量大约是（ ） 相似文献
4.
<正> 例题科学家成功地将人的生长激素基因导入大肠杆菌体内生产出人的生长激素。在该过程中常采用质粒作为运载体,但是把重组质粒导入大肠杆菌细胞时,效果并不好。导入完成后,在得到的大肠杆菌中,实际上有的根本没有导入质粒,有的导入的是普通质粒,只有少数导入的是重组质粒。已知质粒上 相似文献
5.
草鱼对淀粉饲料的消化吸收和利用 总被引：1，自引：0，他引：1
观察了平均体重７．０９ｇ的草鱼经淀粉含量不同的饲料喂养６０ｄ的生长和对饲料的利用情况．结果表明，草鱼的日相对增重率、饲料效率和蛋白质效率在饲料中淀粉含量增加时均下降，但组间差异不显著；饲饲料中纤维素含量升高显著降低草鱼对饲料干物质和淀粉的消化吸收，对蛋白质的消化吸收没有显著影响 相似文献
6.
人生长激素基因转化花叶芋及PEG在转化中的作用 总被引：1，自引：0，他引：1
将人生长激素基因插入pBR322衍生质粒载体pLGV1103 DNA中,通过三亲交配,将重组原粒pLB-9引入携带Ti质粒pGV3850的农杆菌,经同源重组,获得共整合重组体pGL198(hgh)Ti质粒。用叶盘共培养法,将pGL198(hgh)转化单子叶植物花叶芋,获得转基因再生植株。经胭脂碱测定、新霉素磷酸转移酶分析和DNA分子杂交,证明人生长素基因已整合到花叶芋DNA中。还探讨了聚乙二醇(PEG)在植物转化中的作用。 相似文献
7.
短乳酸杆菌对草鱼幼鱼养殖水体和肠道菌群的影响 总被引：2，自引：0，他引：2
在草鱼幼鱼中投喂添加由单一短乳酸杆菌制备的微生态制剂和黄霉素,在60d的投喂期内,采用平板计数法检测好氧性异养菌的总数、总弧菌数和短乳酸杆菌的数量．结果表明,在投喂菌液和冻干菌粉后,养殖水体和草鱼肠道的短乳酸杆菌数均呈上升趋势,在30d后数量达到稳定并在肠道内定植．同时,由于短乳酸杆菌的抑制作用,弧菌的数量下降,以肠道中的弧菌最明显．乳酸菌对养殖水体和草鱼肠道的好氧性异养菌没任何影响．乳酸菌对养殖水体和肠道菌群的影响与抗生素具有相近的效果,表明乳酸菌作为饲料添加剂可以取代抗生素应用在草鱼的养殖中． 相似文献
8.
第I卷（选择题共２０题每题６分共１２０分）在下列各题的四个选项中，只有一个选项是符合题目要求的。１．下列属于蛋白质的一组是（）A．性激素、生长激素、纤维素B．解旋酶、抗体、胰岛素C．血红蛋白、胆固醇、维生素DD．载体、抗体、核糖体２．下列关于水的叙述正确的是（）A．自由水只在血液中流动B．心肌细胞坚硬是因为其中含有大量结合水的缘故C．血液凝固时自由水不会变成结合水D．鸟胚在封闭的卵壳内发育所需的水来自空气３．长期接触X射线的人的后代，遗传病的发病率明显提高。与这一现象有关的是（）A．体细胞、基因重组B… 相似文献
9.
用钝顶螺旋藻进行了藻胆体核心和藻蓝蛋白重组的研究。在室温荧光发射光谱中，藻胆体核心-藻蓝蛋白重组复合物的荧光发射峰位于663nm，与藻蓝蛋白的室温荧光发射峰643nm和藻蓝蛋白 藻胆体核心混合物(未重组)的室温荧光发射峰648nm相比，荧光发射峰向长波方向发生了移动，并向藻胆体核心室温荧光发射峰664nm逼近。说明藻蓝蛋白与藻胆体核心发生了重组，而且重组效果较好。在液氮温度荧光发射光谱中，其结果也表明藻蓝蛋白与藻胆体核心发生了重组。 相似文献
10.
山东电力高专科学校与企业合并重组院校合一，产学研—体化办学，实现了强强联合，资源共享，优势互补，理论教学与实践操作相结合，利用独具特色双师型队伍进行教学、采用“一级管理”的机制进行管理，五年来学校有了长足的发展，今年有两个科技项目被列入国家863计划，学校毕业生一次性就业率达到了94．8%，在历届山东省大学生电子设计竞赛中，我校均取得了良好成绩：1998年获三等奖1项．1999年获二等奖2项．2000年获二等奖2项，2002年获一等奖1项、二等奖1项，2003年获二等奖2项；在历届全国大学生数学建模竞赛中，获1998年省级二等奖1项，1999，2000，2003年均获全国二等奖1项，形成了企业办学的新特色，在教育改革合并重组的今天，山东电专特色办学之路越走越宽广。 相似文献
11.
神经内分泌因子对鱼类生长及繁殖的调控 总被引：1，自引：0，他引：1
谢嘉华 《泉州师范学院学报》2002,20(6):71-75
鱼类的生长和繁殖是密切联系的，分别受生长激素（GH）和促性腺激素（GtH)的调节，而生长激素和促性腺激素的分泌受神经内分泌的双重调节，即下丘脑分泌的生长激素释放因子（GRF）和生长激素抑制因子（SRIF）对生长激素的双重神经内分泌调节，以及促性腺激素释放激素（GnRH)和多巴胺（DA）对促性腺激素的双重神经内分泌调节，此外还受多种神经内分泌因子的影响。 相似文献
12.
Chinese Meishan and Jiangquhai pigs are two of the most prolific pigs in the world, but their growth rate is lower than that of Duroc, Landrace and Pietrain pigs. It is suggested that growth rate is regulated by growth hormone. The objective of the current study was to analyze the porcine growth hormone (pGH) gene polymorphisms based on the polymerase chain reaction restriction fragment-length polymorphism method (PCR-RFLP) for three western meat-type breeds (Duroc, Landrace and Pietrain) and two local Chinese pigs (Meishan and Jiangquhai). Five polymorphic restriction sites were detected with the ApaI, MspI, BspI and HhaI restriction enzymes in two amplified fragments (605 bp, -119 to +486; 506 bp, +206 to +711). Breed difference was found only in the 506 bp fragment. There was no difference in allelic frequencies of BspI and HhaI restriction sites among the five breeds (P>0.05). Landrace and Meishan pigs lacked allele G3 of MspI site. The allele G3 frequency of restriction MspI site of the 506 bp fragment in Pietrain pigs was higher than that in Duroc and Jianquhai pigs (P<0.001). For ApaI site, the Meishan pigs lacked allele G1; no difference was found in allelic frequencies among Pietrain, Duroc, Landrace and Jiangquhai pigs (P>0.05). This new and rapid PCR-RFLP typing method is an attractive tool for analysis of porcine growth hormone gene restriction sites. The differences in MspI and ApaI restriction sites may explain the growth difference between the foreign meat-type breeds above mentioned and local Chinese pigs. 相似文献
13.
Study on pig growth hormone gene polymorphisms in western meat-type breeds and Chinese local breeds 总被引：1，自引：0，他引：1
INTRODUCTIONGrowthhormone (GH)isapeptidehormonewhichregulatesgrowthandvariousmetabolicac tivities (Sterle,1 995;Yuan ,1 996) .InjectionsofGHintogrowingpigsincreasedgrowthrateoftheanimalsandthepercentageofmuscle ,andwhilefataccretionwasdecreased (Bonneau ,… 相似文献
14.
Zhong-hui ZHANG Li-juan DU Di XIANG Shun-ying ZHU Ming-yuan WU Hui-li LU Yan YU Wei HAN 《Journal of Zhejiang University. Science. B》2009,10(2)
Midkine is a heparin-binding growth factor,which plays important roles in the regulation of cell growth and differentiation.The non-tagged recombinant human midkine (rhMK) is therefore required to facilitate its functional studies of this important growth factor.In the present work,rhMK was expressed in Escherichia coli (E.coli) BL21 (DE3).The expression of midkine was efficiently induced by isopropyl-β-D-thiogalactopyranoside (IPTG).After sonication,midkine was recovered in an insoluble form,and was dissolved in guaoidine hydrochloride buffer.Renaturation of the denatured protein was carried out in the defined protein refolding buffer,and the refolded protein was purified using S-Sepharose ion-exchange chromatography.The final preparation of the rhMK was greater than 98% pure as measured by sodium dodecylsulfate-polyacrylamid gel electrophoresis (SDS-PAGE) and reverse phase high performance liquid chromatography (RP-HPLC).The purified rhMK enhanced the proliferation of NIH3T3 cells. 相似文献
15.
Relatively few empirical studies have examined the performance of enumeration indices in correctly identifying longitudinal population heterogeneity when present, and these studies have produced mixed results. In light of these findings, Muthén (2003) suggested that the inclusion of time-invariant (antecedent) and time-varying (concurrent) covariates, as well as allowing the extracted growth mixture classes to predict a distal outcome (consequent covariate), could improve the performance of enumeration indices. This Monte Carlo simulation study examined the performance of a large set of enumeration indices within these generalized growth mixture model (GGMM) conditions, as suggested by Muthén, by manipulating 4 design conditions: (a) sample size, (b) separation distance between adjacent latent growth trajectories, (c) growth trajectory membership proportions, and (d) the amount of mixture model variance explained by the covariates. The findings suggest: (a) at smaller (N = 500) sample sizes, enumeration indices were much more likely to select an incorrect model than the correct one, (b) at larger (N = 3,000) sample sizes, correct model identification occurred only in the largest separation distance and trajectory membership equality conditions, and (c) the inclusion of covariates had a negligible effect at smaller sample sizes, but covariate inclusion had a more favorable effect on data generation model identification in the largest sample size, largest trajectory separation distance, and equal trajectory membership proportions conditions. Suggestions for researchers and future empirical study possibilities are discussed. 相似文献
16.
Zhong-hui Zhang Li-juan Du Di Xiang Shun-ying Zhu Ming-yuan Wu Hui-li Lu Yan Yu Wei Han 《Journal of Zhejiang University. Science. B》2009,10(2):79-86
Midkine is a heparin-binding growth factor, which plays important roles in the regulation of cell growth and differentiation.
The non-tagged recombinant human midkine (rhMK) is therefore required to facilitate its functional studies of this important
growth factor. In the present work, rhMK was expressed in Escherichia coli (E. coli) BL21 (DE3). The expression of midkine was efficiently induced by isopropyl-β-D-thiogalactopyranoside (IPTG). After sonication,
midkine was recovered in an insoluble form, and was dissolved in guanidine hydrochloride buffer. Renaturation of the denatured
protein was carried out in the defined protein refolding buffer, and the refolded protein was purified using S-Sepharose ion-exchange
chromatography. The final preparation of the rhMK was greater than 98% pure as measured by sodium dodecylsulfate-polyacrylamid
gel electrophoresis (SDS-PAGE) and reverse phase high performance liquid chromatography (RP-HPLC). The purified rhMK enhanced
the proliferation of NIH3T3 cells.
Project supported in part by the Hi-Tech Research and Development Program (863) of China (No. 2007AA02Z149) and the Science
and Technology Commission of Shanghai Municipality (No. 075407071), China 相似文献
17.
用滇龙胆的顶芽及侧芽为外植体,以MS培养基为基本培养基,以6-BA/NAA和KT/IAA两组不同浓度组合进行对比实验,研究诱导滇龙胆顶芽及侧芽萌发产生不定芽的最佳条件。发现在诱导率、产生的不定芽数、长势及不定芽出现时间等方面上,BA/NAA两种激素的互作用效果明显优于KT/IAA。其中以MS+BA3.0mg/l+NAA1.5—2.0mg/l的培养基上诱导率较高,可达100%,且小植株生长茁壮,叶色浓绿,大部分在10d左右可萌发出不定芽,产生不定芽数达7—9个。 相似文献
18.
Jing LI Qian YANG Li-hua ZHAO Shu-mei ZHANG Yu-xia WANG Xiao-yu ZHAO 《Journal of Zhejiang University. Science. B》2009,10(4)
An antifungal protein was isolated from a culture of Bacillus subtilis strain B29. The isolation procedure comprised ion exchange chromatography on diethylaminoethyl (DEAE)-52 cellulose and gel filtration chromatography on Bio-Gel P-100.The protein was absorbed on DEAE-cellulose and Bio-Gel P-100. The purified antifungal fraction was designated as B29I, with a molecular mass of 42.3 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), pl value 5.69 by isoelectric focusing (IEF)-PAGE, and 97.81% purity by high performance liquid chromatography (HPLC). B29I exhibited in-hibitory activity on mycelial growth in Fusarium oxysporum, Rhizoctonia solani, Fusarium moniliforme, and Sclerotinia scle-rotiorum. The 50% inhibitory concentrations (IC50) of its antifungal activity toward Fusarium oxysporum and Rhizoctonia solani were 45 and 112 μmol/L, respectively. B291 also demonstrated an inhibitory effect on conidial spore germination of Fusarium oxysporum and suppression of germ-tube elongation, and induced distortion, tumescence, and rupture of a portion of the germi-nated spores. 相似文献
19.
本文研究了黑斑蛙繁殖期血液中性激素与性腺发育、排精、排卵的关系 ,结果表明黑斑蛙每年清明前后产卵 ,产卵季节雄蛙血液中睾酮和雌蛙血液中雌二醇含量匀较高 ,四月中下旬达到最大值 ,繁殖季节过后 ,性激素迅速下降 相似文献
20.
植物生长调节剂能改变植物体内激素水平,调节植物的生长发育.对盛花期毛白杨进行树干滴注生长调节剂试验,结果表明500ppm乙烯利能促进幼果和花(果)序的提前脱落,1000ppm的赤霉素则对花序的提前脱落有利,因而可减轻毛白杨飞絮污染. 相似文献