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991.
部分桂花品种亲缘关系及特有标记的ISSR分析 总被引:4,自引:0,他引:4
利用ISSR分子标记,以柊树[Osmanthus heterophyllus (G.Don.) P.S.Green]和华东木犀(Osmanthus cooperi Hemsl.)为对照种,研究了桂花(Osmanthus fragrans Lour.)81个品种、1个野生种之间的亲缘关系.结果显示;(1)28个引物共获得280个位点,其中多态性位点263个,多态性比率达93.93%,在4个品种群中,银桂品种群的Shannon信息指数(0.370 7)和遗传多样性指数(0.241 7)最高.(2)遗传变异估算结果显示:桂花遗传分化系数为57.39 %,大部分变异存在于品种群之间.(3)聚类分析结果显示,以遗传相似系数0.71为截值,可将84份种质分成 4类,各品种群的品种往往先聚在一起.其中四季桂品种群与秋季开花的3个品种群遗传距离较远,色质较深的金桂品种往往与丹桂品种聚在一起.研究表明,基于ISSR分子标记的聚类结果与基于形态的传统分类学的结果基本相符;引物ISSR12和ISSR27结合可以将84份种质区别开来. 相似文献
992.
PiA水稻悬浮细胞系的建立 总被引:2,自引:0,他引:2
本研究以抗稻瘟病的粳稻PiA开花后12~15d的幼胚为材料,将诱导10~15d的愈伤不经固体培养基继代,直接转到AA液体培养基上,在较短时间内成功建立起了优良的水稻悬浮细胞系;并测定了该悬浮细胞系不同时期的生长特性和分化情况,结果表明悬浮培养适宜的继代天数是7~10d;培养30~120d的细胞分化能力和植株再生能力较好,细胞分化率和成苗率分别为57.1%和20%,为进一步利用悬浮细胞进行遗传转化和原生质体分离奠定了基础。 相似文献
993.
以SGC7901、SW480、HepG2 3种细胞株为研究对象,分析顺铂(CDDP)对干细胞因子(stem cell factor,SCF)基因和蛋白质表达的影响,探讨SCF与消化系统肿瘤的关系.采用MTT方法筛选药物半数抑制浓度,用RT-PCR方法检测SCF mRNA表达量,并用Western Blotting方法检测SCF蛋白质表达水平.结果表明,CDDP可以抑制SCF mRNA在3种细胞株中的表达,差异均有统计学意义(P<0.05).SCF蛋白质在SGC7901细胞实验组与对照组比较差异无统计学意义(P>0.05);SW480、HepG2细胞实验组与对照组比较差异有统计学意义(P<0.05).因此,SCF在消化系统肿瘤细胞增殖过程中可能起重要作用. 相似文献
994.
Reshma Bhowmick Mei Li Jun Sun Sheila A. Baker Christine Insinna Joseph C. Besharse 《Traffic (Copenhagen, Denmark)》2009,10(6):648-663
Intraflagellar transport (IFT) provides a mechanism for the transport of cilium-specific proteins, but the mechanisms for linkage of cargo and IFT proteins have not been identified. Using the sensory outer segments (OS) of photoreceptors, which are derived from sensory cilia, we have identified IFT–cargo complexes containing IFT proteins, kinesin 2 family proteins, two photoreceptor-specific membrane proteins, guanylyl cyclase 1 (GC1, Gucy2e) and rhodopsin (RHO), and the chaperones, mammalian relative of DNAJ, DnajB6 (MRJ), and HSC70 (Hspa8). Analysis of these complexes leads to a model in which MRJ through its binding to IFT88 and GC1 plays a critical role in formation or stabilization of the IFT–cargo complexes. Consistent with the function of MRJ in the activation of HSC70 ATPase activity, Mg-ATP enhances the co-IP of GC1, RHO, and MRJ with IFT proteins. Furthermore, RNAi knockdown of MRJ in IMCD3 cells expressing GC1-green fluorescent protein (GFP) reduces cilium membrane targeting of GC1-GFP without apparent effect on cilium elongation. 相似文献
995.
Xiaowei Pan Hongmei Zhang Mei Li 《Biochemical and biophysical research communications》2009,390(3):597-602
Zeta-crystallin-like quinone oxidoreductase is NAD(P)H-dependent and catalyzes one-electron reduction of certain quinones to generate semiquinone. Here we present the crystal structures of zeta-crystallin-like quinone oxidoreductase from Pseudomonas syringae pv. tomato DC3000 (PtoQOR) and its complexes with NADPH determined at 2.4 and 2.01 Å resolutions, respectively. PtoQOR forms as a homologous dimer, each monomer containing two domains. In the structure of the PtoQOR-NADPH complex, NADPH locates in the groove between the two domains. NADPH binding causes obvious conformational changes in the structure of PtoQOR. The putative substrate-binding site of PtoQOR is wider than that of Escherichia coli and Thermus thermophilus HB8. Activity assays show that PtoQOR has weak 1,4-benzoquinone catalytic activity, and very strong reduction activity towards large substrates such as 9,10-phenanthrenequinone. We propose a model to explain the conformational changes which take place during reduction reactions catalyzed by PtoQOR. 相似文献
996.
This article describes the employment of a novel p-phenol derivative, 4-(1,2,4-triazol-1-yl)phenol (TRP), as a highly potent signal enhancer of the luminol-hydrogen peroxide (H2O2)-horseradish peroxidase (HRP) chemiluminescence (CL) system. The CL reaction conditions were optimized, and the enhancement characteristics of TRP were compared with those of p-iodophenol (PIP). TRP produced a strong enhancement of the CL with the effect of prolonging the light emission. The developed system was then applied to the determination of H2O2 with immobilized HRP using magnetic beads as a solid support. The linear range for H2O2 was 2.0 × 10−6 to 1.0 × 10−3 M. The detection limit for H2O2 was 2.0 × 10−6 M. The proposed sensor was applied successfully to the determination of H2O2 in rainwater. 相似文献
997.
Solid-state NMR spectroscopy is used to determine the membrane-bound topological structure of a cationic β-hairpin antimicrobial peptide in which the number of Arg residues has been halved. The parent peptide, PG-1, was previously found to form transmembrane β-barrels in anionic membranes where the Arg residues complex with the lipid phosphate groups to cause toroidal pore defects in the membrane. In comparison, the charge-attenuated and less active mutant studied here forms β-sheets that lie on the surface of the zwitterionic membrane and only partially insert into the anionic membrane. The mutant also exhibits much looser contact with the lipid headgroups. These results indicate that transmembrane insertion and tight Arg-phosphate association are two important elements for strong antimicrobial activities of this class of peptides. Comparison with other β-hairpin antimicrobial peptides studied so far further suggests a relative potency scale for the various mechanisms of action for the β-sheet family of antimicrobial peptides. The transmembrane insertion-toroidal pore mechanism is the most potent in disrupting the lipid bilayer, followed by the large-amplitude in-plane motional mechanism. The carpet model, where peptides aggregate on the membrane surface to cause lateral expansion and eventual micellization of the membrane, is a weaker mechanism of action. 相似文献
998.
999.
1000.
Mei Kay Lee Ngoc Sang Le Anthony C. Fang Michael T.H. Koh 《Journal of biomechanics》2009,42(3):217-222
Body segment parameters (BSP) are essential input for the computations in kinetics of motion applied in the field of biomechanics. These data are usually obtained from population-specific predictive equations which present limitations in being representative of the population under study. More recently, medical imaging techniques have been adopted but are limited to two-dimensional (2-D) measurements or required extensive tomographic images for three-dimensional (3-D) reconstruction. We proposed an in vivo method to measure 3-D BSP using X-ray imaging and 3-D exterior geometry. Criterion values of the BSP were determined using magnetic resonance imaging (MRI) which has previously been validated. Errors for all BSP values were less than 2% when values derived from our method were compared to the criterion values. We found no significant difference between our method and four selected BSP models in both stance and swing phase. Significant phase effects were observed for our method and other BSP models between stance and swing phase. Significant differences (p<0.05) between root mean square error (RMSE) ranged from 0.0177 to 0.0234 and 0.0234 to 0.097 Nm kg?1 for the knee and hip joints, respectively. However, these BSP variations brought about effects on moment output that were less than 0.09 Nm kg?1. Our findings suggest joint kinetic computations during normal gait are relatively insensitive to BSP variations. However, the influence of BSP cannot be undermined in movements that generate higher acceleration at the limbs. Considering the accuracy of our method, it could be used as a novel in vivo method to obtain direct 3-D BSP measurements. 相似文献