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61.
INTRODUCTION Streptomycetes are gram-positive soil bacteriarenowned for their ability to produce a large numberof different secondary metabolites. Their life cycleinvolves complex morphological differentiation,which is believed to be closely co-ordinated with geneexpression that promotes a variety of physiologicaland structural changes including the onset of antibi-otic biosynthesis. S. coelicolor has been extensivelystudied as a model system with the aid of genetic andmolecular technique…  相似文献   
62.
加拿大奥委会在提升国家队竞技表现、推选本国奥运申办城市、开展奥林匹 克文化教育活动等领域发挥了核心功能。 研究采用文献资料、逻辑分析等方法,归纳总 结加拿大奥委会组织治理的内容与特征,认为其具有清晰的组织使命愿景、民主的议事 决策架构、严格的组织行为监督、良好的财务运行系统和共赢的品牌营销模式。 中国奥 委会可以借鉴其治理经验,保持治理模式的本土化、实现治理目标的完整性、扩大治理 主体的代表性、 提 高 治 理 过 程 的 透 明 度, 不 断 增 强 组 织 治 理 能 力 并 实 现 组 织 治 理 现 代化。  相似文献   
63.
桑科新分类群   总被引:1,自引:0,他引:1  
  相似文献   
64.
运用文献资料调研、专家访谈和 对 比 研 究 等 方 法,在 对 " 技 术 驱 动、法 律 保 障、协同治理、自愿原则" 四位一体的美国标准化管理体制以及" 行政驱动、政府主导" 的 中国标准化管理体制简单介绍的基础上,从制度安排、战略规划和定标流程等三个方面 对中美两国体育标准化建设进行了比较。 借鉴美国经验,我国体育标准化建设应该占 领技术高是、创新引领发展,增加社会参与、扩大标准供给;提升国际化水平、增加标准 适用性。 这对于打造我国的现代化体育产业体系、切实推进体育产业高质量发展、促进 体育产业成为国民经济支柱性产业具有重要的现实意义。  相似文献   
65.
研究了影响难溶金属氢氧化物溶度积 (pKsp)大小的有关因素 ,基于逐步线性回归建立了一个pKsp与有关参数的定量关联模型 随后 ,根据金属离子在周期表中的区域及其结构差异进行了分组建模 ,相关系数R分别达到或接近优级水平 (0 994和 0 981) 对模型进行分析发现 ,影响氢氧化物pKsp 的最重要因素是离子电荷z和半径r  相似文献   
66.
以(NH4)2SO4为唯一氮源,经富集培养、平板涂布分离及平板划线纯化、摇瓶复筛等方法,从当地养殖池水体中分离、筛选氨氮降解菌。根据形态学、生理生化特征分析,对其进行归属鉴定,并研究其降解特性。通过对初步鉴定归属为沙雷氏菌属(Serratia.sp),命名为N-2的氨氮降解菌降解特性的研究,得到其最适降解条件:N-2利用(NH4):S04作唯一氮源时,最适碳源为蔗糖,降解温度为32—37℃,pH为7.0。在最适条件下,当NH4+-N初始质量浓度为50mg/L时,该菌培养至72h氨氮降解率可达97.4%。结果表明,该菌为高效氨氮降解菌,这种土著微生物在修复富营养化水体方面有较好的应用前景。  相似文献   
67.
中学生余暇体育开展的研究   总被引:3,自引:3,他引:0  
通过文献资料法,对中学生余暇体育的内涵、特点和作用进行了详细阐述,旨在通过了解目前我国中学生余暇体育开展的具体情况,进而探讨在素质教育影响下中学生余暇体育开展的途径。  相似文献   
68.
Strain improvement and medium optimization to increase the productivity of spiramycin were carried out. Of oil tolerant mutant strains screened, one mutant, Streptomyces ambofaciens XC 2-37, produced 9% more spiramycin than the parent strain S. ambofaciens XC 1-29. The effects of soybean oil and propyl alcohol on spiramycin production with S. ambofaciens XC 2-37 were studied. The potency of S. ambofaciens XC 2-37 was improved by 61.8% with addition of 2% soybean oil in the fermentation medium and 0.4% propyl alcohol at 24 hours after incubation. The suitable time for feeding propyl alcohol is at 24 hours after incubation in flask fermentation and at 20 hours after incubation in fermentor fermentation. The new process with S. ambofaciens XC 2-37 was scaled up for industrial scale production of spiramycin in a 60 m3 fermentor in Xinchang Pharmaceutical Factory, Zhejiang Medicine Company, Ltd., China, and the potency and productivity of fermentation were improved by 42.9%.  相似文献   
69.
The production of elastase by Bacillus sp. EL31410 at various temperatures was investigated. In order to study the effect of temperature on elastase fermentation, different cultivation temperatures, ranging from 39 ℃ to 28 ℃, were evaluated in shake flask. The result indicated that 37 ℃ was best for cell growth at earlier stage; while maximum elastase activity was obtained when the cells were cultivated at 30 ℃. This result was verified by batch fermentation in 5-L bioreactor under 37 ℃ and 30 ℃ temperature, respectively. The specific cell growth rate at 37 ℃ was higher than that at 30 ℃ latory temperature cultivation mode were evaluated in the next study. When compared to single temperature of 37 ℃ or 30 ℃, both two-stage temperature shift strategy and oscillatory temperature strategy improved biomass but did not yield the same result as expected for elastase production. The maximum biomass (both 8.6 g/L) was achieved at 30 h at 37 ℃, but at 42 h using two-stage temperature cultivation strategy. The highest elastase production (652 U/ml) was observed at 30 ℃ in batch process. It was concluded that cultivation at constant temperature of 30 ℃ was appropriate for elastase production by Bacillus sp. EL31410.  相似文献   
70.
A newly isolated strain EL31410, producing elastase (E.C3.4.4.7) with high elastolytic activity was identified as Bacillus sp. In the medium optimization, it was found that wheat bran and soybean flour hydrosate were the best crude carbon and nitrogen source for enzyme production, respectively. Addition of corn steep flour can affect the bacterium growth and elastase production. A fractional factorial design was applied to study the main factors that affect the enzyme production, and central composite experimental design and response surface methodology were adopted to derive a statistical model for the effect of wheat bran and soybean flour hydrosate on elastase production. The experimental results showed that wheat bran had positive effect but soybean flour hydrosate had negative effect, on enzyme production. An initial concentration of 3.4%(w/v) wheat bran and 9.4%(v/v) soybean flour hydrosate were found to be optimal for enzyme production in batch culture. The time course of elastase production in the optimized medium composition was also described.  相似文献   
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