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31.
32.
高压静电场处理沙棘插条生根状况的初步研究 总被引:2,自引:0,他引:2
用高压静电场处理沙棘插条研究生根状况,方法简便易于处理,该装置适于进行大规模的处理,从目前研究表明:高压静电场对沙棘插条有正刺激效应,并以电场强度为3.9kv/cm,时间为40分钟处理最佳。 相似文献
33.
本文提出了一种检测非真空电束辐射的间接作用的一种方法,根据氧化型和还原型的细胞色素C的吸收光谱不同,从而测量非真空电子束作用对应的辐射分解的自由基总量。 相似文献
34.
We have developed a biochemical approach for identifying the components of cortical actin assembly sites in polarized yeast cells, based on a permeabilized cell assay that we established for actin assembly in vitro. Previous analysis indicated that an activity associated with the cell cortex promotes actin polymerization in the bud. After inactivation by a chemical treatment, this activity can be reconstituted back to the permeabilized cells from a cytoplasmic extract. Fractionation of the extract revealed that the reconstitution depends on two sequentially acting protein factors. Bee1, a cortical actin cytoskeletal protein with sequence homology to Wiskott-Aldrich syndrome protein, is required for the first step of the reconstitution. This finding, together with the severe defects in actin organization associated with the bee1 null mutation, indicates that Bee1 protein plays a direct role in controlling actin polymerization at the cell cortex. The factor that acts in the second step of the reconstitution has been identified by conventional chromatography. It is composed of a novel protein, Pca1. Sequence analysis suggests that Pca1 has the potential to interact with SH3 domain-containing proteins and phospholipids. 相似文献
35.
心肺压力感受器持续卸荷对前臂血流、血管阻力及心率变异性谱的影响 总被引:1,自引:0,他引:1
低压值下体负压(LBNP)可仅使心肺压力感受器卸荷。采用-2kPaLBNP实验结果表明:LBNP既不引起动脉血压变化,也不引起心率改变,但却引起基础胸阻抗(Z。)从对照的21.8±0.4升高到22.5±0.5Ω(P<0.01),前臂血管阻力(FVR)从12.3±0.9升高到19.9±1.4U(P<0.01),前臂血流(FBF)从对照时7.1±0.5降低到4.3±0.3ml·min ̄(-1)·100ml ̄(-1),心率变异性谱(HRV)未发生任何变化,即心肺压力感受器卸荷时心脏自主神经活动水平与均衡性不受影响。由于FVR和FBF的变化可间接反映外周血管交感传出活动水平,上述实验结果提示,心肺压力感受器对外周血管及心脏自主神经活动的调节可能存在机能分化现象。 相似文献
36.
宁夏分布有大面积的流动沙地和盐碱地,因此,引进适生的植物对治沙造林、改善生态环境有重大意义。本文报道沙拐枣属(Calligonum L.)和柽柳属(Tamarix L.)的引选及抗逆性造林技术方面的结果。 相似文献
37.
The Hyper-Gene Conversion Hpr5-1 Mutation of Saccharomyces Cerevisiae Is an Allele of the Srs2/Radh Gene 总被引:7,自引:2,他引:5
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The HPR5 gene has been defined by the mutation hpr5-1 that results in an increased rate of gene conversion. This mutation suppresses the UV sensitive phenotype of rad18 mutations in hpr5-1 rad18 double mutants by channeling the aborted repair events into a recombination repair pathway. The HPR5 gene has been cloned and is shown to be allelic to the SRS2/RADH gene, a putative DNA helicase. The HPR5 gene, which is nonessential, is tightly linked to the ARG3 locus chromosome X. The hpr5-1 allele contains missense mutation in the putative ATP binding domain. A comparison of the recombination properties of the hpr5-1 allele and the null allele suggests that recombination events in hpr5 defective strains can be generated by several mechanisms. We propose that the HPR5 gene functions in the RAD6 repair pathway. 相似文献
38.
Huiling Hao Yunquan Jiang S. J. Zhang Peng Zhang Rong X. Zeng Marietta Y. W. T. Lee 《Chromosoma》1992,102(Z1):S121-S127
A continuing theme of our laboraory, has been the understanding of human DNA polymerases at the structural level. We have
purified DNA polymerases delta, epsilon and alpha from human placenta. Monoclonal antibodies to these polymerases were isolated
and used as tools to study their immunochemical relationships. These studies have shown that while DNA polymerases delta,
epsilon and alpha are discrete protiens, they must share common structural features by virtue of the ability of several of
our monoclonal antibodies to exhibit cross-reactivity. A second approach we have taken is the molecular cloning of human DNA
polymerase delta and epsilon. We have cloned the DNA polymerase delta cDNA, and this has allowed us to compare its primary
structure to those of human polymerase alpha and other members of this polymerase family. Multiple sequence alignments have
revealed that human DNA polymerase delta is also closely related to the herpes virus family of DNA polymerases. In situ hybridization
has shown that the human DNA polymerase delta gene is localized to chromosome 19 q13.3–q13.4. In order to further determine
the functional regions of the DNA polymerase δ structure we are currently expressing human pol δ inE. coli and baculovirus systems. Other work in our laboratory is directed toward examining the expression of DNA polymerase δ during
the cell cycle. 相似文献
39.
【目的】采用Plackett-Burman Design (PBD)与均匀设计(Uniform Design, UD) 优化玫瑰色微球菌(Micrococcus roseus)固定化脱氮的条件,以提高其脱氮性能。【方法】选择聚乙烯醇(Polyvinyl alcohol,PVA)与海藻酸钠(Sodium alginate,SA)作为固定化细胞材料,研究其成球方式与性能,应用PBD对9个影响脱氮效果的因素进行显著性检验,筛选出PVA、SA、温度、菌液接种量、菌球量5个显著性因素(P<0.05)。采用UD对5个显著因素进行条件优化,优化数据通过Minitab与Matlab软件进行逐步回归分析,并建立二阶多项式模型。【结果】最优脱氮条件为PVA 9.6%、SA 2.2%、温度33.4 °C、菌液接种量8%、菌球量500个/100 mL,连续脱氮72 h,最高脱氮率达到60.9%。【结论】PBD与UD的联合使用能够在显著因子筛选与寻优中发挥重要的作用。连续脱氮试验表明,玫瑰色微球菌去除氨氮主要通过同化、硝化与反硝化途径。 相似文献
40.