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双功能枯草杆菌诱导型高效表达分泌载体的构建与鉴定 总被引:1,自引:0,他引:1
利用大肠杆菌质粒pSP72和枯草杆菌质粒pUB18共整合得到双功能克隆载体pSB。在pSB多克隆位点依次引入枯草杆菌果聚糖蔗糖酶基因启动子-信号肽序列sacBp.s.、地衣芽孢杆菌淀粉酶基因终止子序列α-amyT和短小芽孢杆菌增强子基因degQ,最终构建了双功能枯草杆菌诱导型高效表达分泌载体pSBPTQ。将VasostatinⅠ基因作为靶基因检测sacBp.s.、α-amyT和degQ在pSBPTQ进行外源基因表达时的功能,结果表明,在蔗糖诱导下,sacB启动子有效启动了Vasostatin I基因的表达和分泌,α-amy T提高了VasostatinⅠ基因的转录效率,而degQ明显增强了VasostatinⅠ基因的表达水平。VasostatinⅠ基因在蔗糖诱导下成功表达并分泌到枯草杆菌细胞外,蛋白质分泌效率达到90%左右。质粒稳定性试验结果表明,经过40个世代之后,质粒pSBPTQ在枯草杆菌DB1342中仍旧保持在83%以上。 相似文献
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短小芽孢杆菌degQ基因的克隆与鉴定 总被引:3,自引:0,他引:3
degQ基因编码一个由46个氨基酸组成的多肽,能增强许多芽孢杆菌胞外酶基因的表达,以PMK4作克隆体构建短小芽孢杆菌基因库,并用DNA探针原位杂次法从中钓出degQ基因,对克隆基因的DNA序列进行了分析并证明克隆的短小芽孢杆菌degQ基因具有增强枯草杆菌蛋白酶和果聚糖蔗糖酶基因表达的能力,degQ基因克隆有助于研究芽孢杆菌的正调控机一并可望提高外源基因在芽孢杆菌中表达。 相似文献
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摘要:【目的】从耐碱性木聚糖酶高产短小芽孢杆菌中克隆得到带有自身启动子的木聚糖酶基因,将其在巨大芽孢杆菌中进行表达,并对表达产物进行性质分析。【方法】将克隆得到的木聚糖酶基因xynA以及带有自身启动子序列的结构基因, 构建在芽孢杆菌表达载体pWH1520和改造后的载体pWG03中,得到重组质粒pWTEJX和pWGXYN,分别转化到巨大芽孢杆菌BM70中,获得重组巨大芽孢杆菌BMJXH9和BMGpp12;经过诱导产酶培养,均得到分泌表达。【结论】重组巨大芽孢杆菌BMGpp12比BMJXH9产酶活力提高了三倍 相似文献
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获得高抗虫转双基因烟草 总被引:30,自引:4,他引:30
利用DNA合成仪人工合成了豇豆胰蛋白酶抑制剂(cpTl)的cDNA编码全序列。合成的基因经过克隆和序列分析后.克隆到植物高效表达载体上,并转化农杆菌,通过共转化的方法,将cpTI基因和经人工改造的苏云金芽孢杆菌(B.T)δ-内毒素基因共转化烟草,得到经PCR扩增并Southern-blotting验证的分别含有CpTI和B.T基因的植株以及同时含有CpTI和B.T基因的植株。利用棉铃虫幼虫进行的杀虫测试表明.转基因烟草和对照烟草相比具有明显的杀虫活性-同时转双基因的烟草和转单一基因的烟草相比具有增强的杀虫活性。 相似文献
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利用TAIL-PCR(Thermal asymmetric interlaced PCR)从短小芽孢杆菌基因组中扩增到碱性蛋白酶基因编码区上游的启动子片段。对该片段的序列测定和分析表明, 此片段长797 bp, 但与基因表达有关的序列长约390 bp。对启动子片段进行不同长度的缺失突变, 以获得最小的基因启动子片段, 结果表明, 该基因起始密码子上游约160 bp的DNA片段就可以启动基因的表达。将含有该片段的碱性蛋白酶基因WApQ3插入大肠杆菌-芽孢杆菌穿梭质粒载体pSUGV4中, 构建了碱性蛋白酶基因表达质粒pSUBpWApQ3。将该质粒分别转入枯草芽孢杆菌和短小芽孢杆菌中表达, 可在胞外检测到碱性蛋白酶活性, 最高酶活分别为466.5 U/mL和3060 U/mL。 相似文献
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枯草芽孢杆菌C-36内切葡聚糖酶基因的克隆及其在大肠杆菌中融合表达 总被引:2,自引:0,他引:2
以自行分离筛选出的天然枯草芽孢杆菌(Bacillus subtilis)C-36的染色体DNA为模板,PCR扩增得到含有内切葡聚糖酶基因的DNA片段,将其克隆到pMD-18T载体中,序列分析表明,克隆得到的DNA片段全长1602bp,编码一个含有499个氨基酸的多肽。与其他芽孢杆菌内切葡聚糖酶基因序列比对,其核苷酸同源率为90%~93%,其编码的氨基酸序列的同源性在90%~98%,已将此基因注册GenBank(DQ782954)。将含内切葡聚糖酶基因的重组克隆质粒进行亚克隆,用Kpn I和EcoR I双酶切后,与相同酶切的表达载体pET-32a相连接,并导入大肠杆菌BL21中表达。蛋白质电泳实验结果表明在6.47×10^4处有表达蛋白带。经测定表达蛋白比酶活力达99.02U/mL,为出发菌C-36(63.78U/mL)的1.55倍。 相似文献
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《生物技术通报》2016,(11)
为了利用荧光定量PCR方法分析短小芽孢杆菌的基因表达水平,需要首先确定适合该菌株的荧光定量PCR分析内参基因。以短小芽孢杆菌的16S rRNA、mecA、cadR、rpoB及sphP共5个基因作为候选内参基因,利用实时荧光定量PCR的方法分析这5个候选基因在短小芽孢杆菌发酵培养不同时间点的表达情况,再用geNorm和NormFinder软件评估它们的表达稳定性。结果显示,利用geNorm软件分析得出16S rRNA和mecA是表达最稳定的基因,最适内参基因数为2。NormFindr软件分析得出mecA为最稳定的基因。对短小芽孢杆菌3个功能基因的差异表达分析结果表明,16S rRNA和mecA都是合适的内参基因,而mecA基因由于表达丰度适中,更适合于作为内参基因研究结构基因的表达。为了得到更准确的差异表达结果,也可用两个基因同时进行校正。 相似文献
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Characterization of degQ and degS, Escherichia coli genes encoding homologs of the DegP protease. 总被引:5,自引:3,他引:2
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The degQ and degS genes of Escherichia coli encode proteins of 455 and 355 residues, respectively, which are homologs of the DegP protease. The purified DegQ protein has the properties of a serine endoprotease and is processed by the removal of a 27-residue amino-terminal signal sequence. A plasmid expressing degQ rescues the temperature-sensitive phenotype of a strain bearing the degP41 deletion, implying that DegQ, like DegP, functions as a periplasmic protease in vivo. Deletions in the degQ gene cause no obvious growth defect, while those in the degS gene result in a small-colony phenotype. The latter phenotype is rescued by a plasmid expressing the degS gene but not by plasmids expressing the degQ or degP genes. This result and the inability of a plasmid expressing degS to rescue the temperature-sensitive degP41 phenotype indicate that the DegS protein is functionally different from the DegQ and DegP proteins. 相似文献
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Signal transduction pathway controlling synthesis of a class of degradative enzymes in Bacillus subtilis: expression of the regulatory genes and analysis of mutations in degS and degU. 总被引:37,自引:32,他引:5
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T Msadek F Kunst D Henner A Klier G Rapoport R Dedonder 《Journal of bacteriology》1990,172(2):824-834
The rates of synthesis of a class of both secreted and intracellular degradative enzymes in Bacillus subtilis are controlled by a signal transduction pathway defined by at least four regulatory genes: degS, degU, degQ (formerly sacQ), and degR (formerly prtR). The DegS-DegU proteins show amino acid similarities with two-component procaryotic modulator-effector pairs such as NtrB-NtrC, CheA-CheY, and EnvZ-OmpR. By analogy with these systems, it is possible that DegS is a protein kinase which could catalyze the transfer of a phosphoryl moiety to DegU, which acts as a positive regulator. DegR and DegQ correspond to polypeptides of 60 and 46 amino acids, respectively, which also activate the synthesis of degradative enzymes. We show that the degS and degU genes are organized in an operon. The putative sigma A promoter of the operon was mapped upstream from degS. Mutations in degS and degU were characterized at the molecular level, and their effects on transformability and cell motility were studied. The expression of degQ was shown to be subject both to catabolite repression and DegS-DegU-mediated control, allowing an increase in the rate of synthesis of degQ under conditions of nitrogen starvation. These results are consistent with the hypothesis that this control system responds to an environmental signal such as limitations of nitrogen, carbon, or phosphate sources. 相似文献
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Suppressive subtraction hybridization (SSH) was used to identify differentially expressed genes in goat (Capra hircus) hair follicle anagen-catagen transition. The cDNA fragments, derived from SSH positive subtractive library (tester: anagen-catagen transition, driver: later anagen), were cloned into pEGM-T vector. Two hundred cDNA fragments screened from this library were subjected to identify forty-five unregulated isolates. Sequence analysis revealed that these fragments represented twenty-three genes. Blasting analysis with database in GenBank showed that twenty genes were previously clearly annotated, two were homologous to un-annotated expressed sequence tag (ESTs), and one might be novel. To identify characters of gene expression, seven genes in later anagen and anagen-catagen transition skin tissues were chosen for quantitative real-time PCR. Results indicated that expression of these seven genes varied much, reaching threefold among them, furthering indicating that expression of those genes was up-regulation in the anagen-catagen transition. We characterized expression levels of this potential novel gene and the goat ectodysplasin A during differential stages of hair cycle. These profiles suggested that these two genes might play a role in the goat secondary hair follicle cycle. 相似文献
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玉米耐铝毒基因的分离 总被引:12,自引:0,他引:12
以抑制消减杂交(SSH)为手段,以玉米对铝敏感的自交系Mo17和耐铝的自交系TL94B为材料,分别构建它们的正向和反向消减文库,分别筛选获得了124、47、103和64个阳性克隆。对文库的鉴定表明,插入片段分布在0.25-1.0kb之间,阳性克隆率在18%左右。对338个阳性克隆进行测序,得到232种表达序列标签(EST),其中70.2%的EST可推测其功能。结果表明,玉米的铝离子胁迫反应涉及胁迫因子的信号传导、响应基因的转录表达与调控、物质的合成与运输、细胞结构和功能的改变等。 相似文献