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931.
932.
发根农杆菌Ri质粒研究进展 总被引:7,自引:0,他引:7
就发根农杆菌Ri质粒的研究进展进行了综述和展望。包括Ri质粒的特性,转化机制及转化方法,影响农杆菌转化成功的因素以及发根农杆菌的应用。 相似文献
933.
HyTK基因转移联合ganciclovir对瘢痕成纤维细胞的体外杀伤作用 总被引:1,自引:0,他引:1
增生性瘢痕和瘢痕疙瘩的过度增生主要是由于高度增生活性的成纤维细胞的数量异常增多及细胞外基质合成增加所致.用逆转录病毒载体介导单纯疱疹病毒胸苷激酶基因(HSVtk)的转移,随后应用药物9-(1,3-二羟基-丙氧基-甲基)鸟嘌呤(ganciclovir,GCV)可选择性地杀死增生细胞.采用组织块贴壁法在体外原代培养成功增生性瘢痕病人的成纤维细胞(FB).重组逆转录病毒GTK转染FB细胞后,用hygromycinB筛选出阳性细胞克隆(FB/GTK),经PCR方法检测证明HyTK基因已成功地导入FB中,但不含可复制的辅助病毒.分别用不同浓度的GCV作用于FB/GTK及FB,光镜下观察不同时间后细胞形态变化及MTT法检测细胞活性.结果表明,GCV浓度大于0.1μmol/L时即对FB/GTK有显著的杀伤作用,且具有强有力的“旁观者效应” 相似文献
934.
应用球孢白僵菌防治马尾松毛虫的策略及其生物多样性基础的研究 总被引:8,自引:8,他引:8
对3种不同方式应用球孢白僵菌防治马尾松毛虫的结果表明,3个林场的虫口在连续4年内均被抑制在低水平,但松毛虫种群动态不同:以淹没式施放白僵菌为主,但有时也淹没式施放化学杀虫剂的麻姑山林场平均虫口密度为3.16±4.94条·株-1,波动最大;长期接种式应用白僵菌的戴公山林场平均虫口密度只有0.09±0.14条·株-1,一直处于低密度状态;以化学农药处理小面积虫源地结合不频繁地淹没式施放白僵菌的金寺山林场平均虫口密度为1.45±2.29条·株-1,偶可达防治指标.对群落组成的调查结果表明,从麻姑山、金寺山到戴公山,动物和虫生真菌群落各物种的总个体数递减,而总物种数、总物种数与总个体数的比值,天敌与害虫种数和个体数的比值以及群落多样性指数皆递增,表明群落多样性渐趋丰富,食物链网渐趋复杂,群落稳定性和对害虫的自然控制能力逐渐增强.对群落动态的主成分分析进一步表明,从麻姑山、金寺山到戴公山,动物和虫生真菌群落的演化时序分明,趋于稳定,自我调节力强. 相似文献
935.
中国牛朊病毒基因的克隆和序列分析 总被引:6,自引:0,他引:6
从中国牛外周血中分离淋巴细胞,提取基因组DNA.用所设计引物以聚合酶链式反应扩增出不致病的朊病毒蛋白(PrP~c)基因,并克隆到pGEM-Teasy Vector.序列分析表明所克隆的牛PrP~c的片段大小为795bp,包含了牛朊病毒基因的完整编码区序列.该基因无内含子,同国外报道的已知序列完全相同. 相似文献
936.
Background and Aims
Great attention has been paid to N2O emissions from paddy soils under summer rice-winter wheat double-crop rotation, while less focus was given to the NO emissions. Besides, neither mechanism is completely understood. Therefore, this study aimed at evaluating the relative importance of nitrification and denitrification to N2O and NO emissions from the two soils at different soil moisture contentsMethods
N2O and NO emissions during one winter wheat season were simultaneously measured in situ in two rice-wheat based field plots at two different locations in Jiangsu Province, China. One soil was neutral in pH with silt loam texture (NSL), the other soil alkaline in pH with a clay texture (AC). A 15?N tracer incubation experiment was conducted in the laboratory to evaluate the relative importance of nitrification and denitrification for N2O and NO emissions at soil moisture contents of 40 % water holding capacity (WHC), 65 % WHC and 90 % WHC.Results
Higher N2O emission rates in the AC soil than in the NSL soil were found both in the field and in the laboratory experiments; however, the differences in N2O emissions between AC soil and NSL soil were smaller in the field than in the laboratory. In the latter experiment, nitrification was observed to be the more important source of N2O emissions (>70 %) than denitrification, regardless of the soils and moisture treatments, with the only exception of the AC soil at 90 % WHC, at which the contributions of nitrification and denitrification to N2O emissions were comparable. The ratios of NO/N2O also supported the evidence that the nitrification process was the dominant source of N2O and NO both in situ and in the laboratory. The proportion of nitrified N emitted as N2O (P N2O ) in NSL soil were around 0.02 % in all three moisture treatments, however, P N2O in the AC soil (0.04 % to 0.10 %) tended to decrease with increasing soil moisture content.Conclusions
Our results suggest that N2O emission rates obtained from laboratory incubation experiments are not suitable for the estimation of the true amount of N2O fluxes on a field scale. Besides, the variations of P N2O with soil property and soil moisture content should be taken into account in model simulations of N2O emission from soils. 相似文献937.
作为小GTP酶Arf6的鸟甘酸交换因子(GEF),人EFA6A蛋白主要包含PH和Sec7两个结构域,Sec7是行使GEF功能的核心区域。通过分析Jpred、Uniprot等生物信息学软件的预测结果,从全长1 024 aa中选取的重组Sec7结构域的边界为506-719,共214 aa。以人脑cDNA文库为模板,通过优化PCR程序成功扩增出Sec7基因,经NdeI和XhoI双酶切后亚克隆至原核表达载体p28a中,成功构建p28-Sec7重组子,测序结果与NCBI中公布的序列100%吻合。将重组质粒p28-Sec7转化至BL21-Gold(DE3)宿主菌中,终浓度0.3 mmol/L IPTG、16℃、24 h诱导表达,重组蛋白经过Ni柱和分子筛两步纯化。试验结果显示,重组Sec7成功表达,性质均一,纯度高于95%,表达量为70 mg/L。 相似文献
938.
Hyo-Kyoung Won So-Jung Park Dong-Kyu Kim Myeung Ju Shin Nari Kim Song-Hee Lee Young-Chul Kwon Han Kyu Ko Hyeon-Su Ro Hyun-Sook Lee 《Journal of microbiology (Seoul, Korea)》2013,51(1):118-122
A mycovirus was isolated from an edible mushroom, Lentinula edodes, that was suffering from a severe epidemic. Fractionation of the diseased cell extract by isopycnic centrifugation with 50% CsCl revealed that the diseased mushroom was infected by Lentinula edodes spherical virus (LeSV), a new spherical virus with a diameter of 55 nm. The particle of LeSV encapsidated the 12 kb RNA genome by a 120 kDa coat protein. BLAST analysis of the partially sequenced LeSV genome showed 95% sequence identity with a putative RNA-dependent RNA polymerase (RdRp) gene of the mycovirus HKB, which was previously reported as being a double-stranded RNA (dsRNA) element. In contrast to HKB, the RNA genome in LeSV is encapsidated by the 120 kDa coat protein. To confirm that the LeSV coat protein is encoded by the viral genome, the N-terminal amino acid sequence of the coat protein was determined. The resulting N-terminal amino acid sequence, N-SALDVAPVVPELYFXXLEV-C, was found to be located in the middle of the HKB ORF1, suggesting that the LeSV coat protein was indeed encoded by the virus. To detect LeSV in L. edodes, a primer set targeting the RdRp gene was designed based on the partial sequence of the LeSV genome. RT-PCR analysis showed that 56 of the 84 commercially available dikaryotic cultivars carry LeSV. The transmission pattern of the virus was determined by analysing basidiospores from LeSV-infected and LeSV-free fruiting bodies. Nine out of 10 basidiospores from the LeSV-infected cultivars contained the virus while the spores from the LeSV-free parent were free of LeSV, suggesting that vertical transmission is the primary mode of LeSV propagation. 相似文献
939.
Seongah Han Lauretta LeVoci Paul Fischer Sheng-Ping Wang Karen Gagen Ying Chen Dan Xie Timothy Fisher Anka G. Ehrhardt Andrea M. Peier Douglas G. Johns 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2013,1831(4):825-833
Cholesteryl ester transfer protein (CETP) is a target of therapeutic intervention for coronary heart disease. Anacetrapib, a potent inhibitor of CETP, has been shown to reduce LDL-cholesterol by 40% and increase HDL-cholesterol by 140% in patients, and is currently being evaluated in a phase III cardiovascular outcomes trial. HDL is known to possess anti-inflammatory properties, however with such large increases in HDL-cholesterol, it is unclear whether CETP inhibition perturbs HDL functionality such as anti-inflammatory effects on endothelial cells. The purpose of the present study was to determine whether CETP inhibition by anacetrapib affects the anti-inflammatory properties of HDL. HDL was isolated from either hamsters treated with vehicle or anacetrapib for 2 weeks, or from normal human subjects treated either placebo, 20 mg, or 150 mg anacetrapib daily for 2 weeks. Anacetrapib treatment increased plasma HDL cholesterol levels by 65% and between 48 and 82% in hamsters and humans, respectively. Pre-incubation of human aortic endothelial cells with HDL isolated from both control and anacetrapib treated hamsters suppressed TNFα induced expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and E-selectin. Similar results were obtained with human HDL samples pre and post treatment with placebo or anacetrapib. Further, HDL inhibited TNFα-induced MCP-1 secretion, monocyte adhesion and NF-κB activation in endothelial cells, and the inhibition was similar between control and anacetrapib treated groups. These studies demonstrate that anacetrapib treatment does not impair the ability of HDL to suppress an inflammatory response in endothelial cells. 相似文献
940.