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761.
C1 SnoRNA,水稻中一种新的核仁小分子RNA 总被引:1,自引:0,他引:1
通过计算机分析国际分子生物学数据库和cDNA序列分析等方法,在水稻(Oryzasativa)中发现了一种新的核仁小分子RNA:C1SnoRNA.该RNA具有boxC,boxD和末端碱基配对区等典型的核仁小分子RNA结构特征;并有14个核苷酸与水稻18srRNA中一段保守序列互补.推测C1SnoRNA可能在18srRNA甲基化过程中起重要作用.编码C1SnoRNA的基因位于水稻Hsp70基因的第一个内含子中.这是在水稻中发现的第一个由基因内含子编码的SnoRNA. 相似文献
762.
763.
二手船购置价格的确定 总被引:2,自引:0,他引:2
张仁颐 《上海交通大学学报》1996,30(10):69-72
从定性和定量两个方面分析了影响二手船购置价格的各种因素.用随机模拟的方法建立了船舶市场和航运市场中各参数关系的分析模型和计算机流程,并以一艘1.5万t载重量的多用途二手船为例,从航线、货种和运费率等方面入手,计算并分析了该船在各种营运条件下的利润、净现值和平均年盈利等经济指标及风险概率,从而使购置价格的确定建立在科学的基础上. 相似文献
764.
765.
本文以贵阳市某区为例,分析了城市地价变化的影响因子,探讨了地价的评估方法,计算出了研究区的平均地价及基准地价,为有关部门制定合理的城镇土地有偿使用对策、完善地产市场提供了依据。 相似文献
766.
在对具有强制推秧功能分插机构的基本机构进行运动分析的基础上,首次采用高副低代的方法及相对运动中的质点动能定理对推秧器进行分析,并对运动链中推秧凸轮进行分析和研究,同时对国产22T-935型插秧凸轮提出改进意见和设计方案,为进一步对插秧机进行动力性能分析和改进奠定了理论基础。 相似文献
767.
人造花岗岩材料以其优异的动态性能,在精密机械领域里崭露头角。南通机床厂首次将这种颇有前途的新型材料应用于XH714型立式加工中心的基础构件,研究解决了配方、模具设计、浇制工艺、降低成本等一系列关键问题,达到了预期的目标。该床身的动静态性能明显优于铸铁床身。 相似文献
768.
Inducible expression pattern of rice Bowman-Birk inhibitor gene<Emphasis Type="Italic">OsWIP1-2</Emphasis> and its protease inhibitory activity 总被引:3,自引:0,他引:3
CHENJun LIUJing GUOLei QULijia CHENZhangliang GUHongya 《科学通报(英文版)》2004,49(9):895-899
The WIP1-2 gene was cloned from rice. It be-longs to the Bowman-Birk inhibitor gene family. Northernblot showed that expression of this gene was induced bywounding and jasmonic acid (JA). It indicates that the OsWIPI gene plays an important role in the rice defense sys-tem. The OsWIP1-2 was cloned into pET28a and expressed inE. coli. Its expressed product was purified in the form offusion protein and tested for the inhibitory activities againsttrypsin and chymotrypsin. It was found that the fusion pro-tein could inhibit chymotrypsin, but not trypsin. It was alsofound that the His tag at its C-terminal affected its inhibitoryactivity significantly. The fusion protein with a naturalC-terminal had the inhibitory activity, while no inhibitoryactivity was detected in the fusion protein with a (His)6-tag atits C-terminal. This implies that extra amino acid residues atthe C-terminal of OsWIP1-2 may interfere with its correctfolding. The inhibitory assay indicated that the members ofrice Bowman-Birk inhibitor gene family probably differenti-ated both in their structure and function. 相似文献
769.
WANGYaling LIQun HEZuhua 《科学通报(英文版)》2004,49(2):131-135
Cytochrome P450 gene superfamily is widely involved in diverse processes of plant development and environmental responses including defense response to pathogens.We previously isolated a rice cDNA fragment in a DD-PCR screening for blast fungus-induced genes. In the current study, we isolated a CYP72A gene cluster consisting of 7 P450 CYP72A genes (CYP72A17-23) with the conserved cDNA sequence through the public rice genome data. There are total 14 putative CYP72A members in the rice genome, with high diversity at N-terminal sequences while high homology at C-terminal sequences of those 14 putative proteins. We analyzed expression profiles of the cloned 7 CYP72A genes during pathogen infection and development. The results showed that expression of CYP72A18, 19, 22 and 23 was differentially regulated in the incompatible and compatible interactions between rice and blast fungus. Except CYP72A20, a pseudogene, other 6 CYP72A genes also exhibited temporal and spatial expression patterns, respectively.These findings provide fundamental data for rice P450 gene function analysis. 相似文献
770.
ZHUYongsheng CHENBaotang YUShunwu ZHANGDuanpin ZHANGXueqin YANQiusheng 《科学通报(英文版)》2004,49(14):1481-1484
Asymmetric somatic hybrid plants were produced between cultivated rice (Oryza sativa L.) and wild species [O. meyeriana (Zoll. etMor, exSteud.)] with high resistance to rice bacterial blight. X-ray-irradiated protoplasts of the wild species were used as donor and chemically fused with iodoacetamide-inactivated protoplasts of rice cv. 02428 to produce hybrids. Seventy-two plants were regenerated from 623 calli based on metabolic complementation. The morphological characters of the plants closely resembled that of the rice. Simple sequence repeats were employed to identify their hybridity. Cytological analysis of root-tips revealed that their chromosome number varied in the range of 27--38. The somatic hybrids were inoculated with strains of Xanthamonas oryzae pv. oryzae at adult growth stage and demonstrated the resistance to bacterial blight introgression from the O. meyeriana. 相似文献