Fine mapping of the rice bacterial blight resistance gene Xa-4 and its co-segregation marker

An F₂ population developed from theXa-4 near isogenic lines, IR24 and IRBB4, was used for fine mapping of the rice bacterial blight resistance gene,Xa-4. Some restriction fragment length polymorphism (RFLP) markers on the high-density map constructed by Harushima et al. and the amplified DNA fragments homologous to the conserved domains of plant disease resistance (R) genes were used to construct the genetic linkage map around the geneXa-4 by scoring susceptible individuals in the population.Xa-4 was mapped between the RFLP marker G181 and the polymerase chain reaction (PCR) marker M55. The R gene homologous fragment marker RS13 was found co-segregating withXa-4 by analyzing all the plants in the population. This result opened an approach to map-based cloning of this gene, and marker RS13 can be applied to molecular marker-assisted selection ofXa-4 in rice breeding programs.     

药用植物复方制剂抑菌作用研究

采用固体平板稀释方法,通过正交设计,对以苦参、蛇床子、黄连、青蒿等几种药用植物为主要原料的复方制剂提取工艺参数进行了试验研究,测定了不同条件提取液对大肠杆菌、金黄色葡萄球菌、柘草芽孢杆菌、热带假丝酵母、黄曲霉等五种微生物的抑菌效果.结果表明,不同的提取溶剂、不同的提取pH值、不同的提取温度下的提取液,对于不同的微生物具有不同的抑菌作用,通过综合比较分析认为,提取溶剂对提取液抑菌效果的影响力最大;70℃、30%乙醇和pH5.0条件下的提取液抑菌效果最好,是最佳的提取工艺条件.     

新型蛋白农药发酵工艺与应用研究

项目研究在构建Harpin蛋白农药高效表达工程菌基础上,开展了工程菌发酵参数研究和规模发酵实验研究,实验筛选出两种廉价诱导剂;在1 000 L发酵罐中Harpin蛋白表达量最高达到4.78 g/L以上,且该蛋白能有效防止细菌性软腐病的发生.     

16S rDNA克隆文库法分析地下水生物反硝化系统细菌种群多样性

采集地下水硝酸盐生物反硝化系统内的污泥样品,提取污泥样品中微生物的总DNA,构建细菌16S rDNA基因片段克隆文库,并通过16S rDNA序列系统发育分析,对反硝化系统内的细菌种群多样性以及菌群结构进行了研究。结果表明,地下水生物反硝化系统内细菌具有高度多样性,样品文库分为9个细菌类群,优势菌群为β-Proteobacteria(67.11%)和Bacteroidetes(15.79%),其中,β-proteobacteria为最优势菌群,以Rhodocyclaceae为主。对反硝化系统内细菌种群多样性的研究有利于确定优势菌种,为地下水硝酸盐生物反硝化修复奠定理论基础。     

一株酯化酶细菌的分离、鉴定及代谢产物特征

研究不同培养条件下酯化酶细菌的代谢产物特征。从浓香型大曲中分离得到一株产酯化酶细菌,用B iolog微生物自动分析系统进行鉴定,改变发酵时间、发酵初始pH值和培养温度等培养条件,用乙醇对发酵液进行萃取,并用气相色谱-质谱联用法(GC-MS)对其进行鉴定分析。结果表明:该菌株为嗜热葡糖苷酶芽孢杆菌(Geobacillus thermoglucosidasius)。随着培养时间的延长,甲醇及各种高级醇逐渐减少甚至消失,而酯类物质则逐渐增加;随发酵初始pH值的增加,酸类物质有所减少,在pH为7.5时,产生了较多的酯类物质,但乙酸、3-羟基-2-丁酮、乙醛和3-甲基-丁醇等代谢产物不会随发酵初始pH值变化而变化;随着培养温度的升高,酸类物质和醇类物质的种类有所增加,当培养温度为35℃时,产生更多的酯类物质。     

盐酸瑞芬太尼细菌内毒素检查法的建立

目的:建立盐酸瑞芬太尼的细菌内毒素检查法.方法:参照《中国药典》2005年版二部附录"细菌内毒素检查法",用不同厂家的鲎试剂对不同批号的盐酸瑞芬太尼分别进行干扰试验,考察确立盐酸瑞芬太尼的细菌内毒素检查法.结果:采用灵敏度为0.5 IU.mL-1的鲎试剂,将本品稀释到0.254 mg.mL-1以下,对鲎试剂的凝集反应无干扰.结论:本品可用细菌内毒素检查法来控制内毒素,其细菌内毒素限值可定为20 IU.mg-1.     

硝基苯生产废水高效处理工艺研究

针对硝基苯废水难降解的特点,研究采用投加硝基苯废水降解菌群和“循环式电极反应固定床－兼性厌氧水解－投加粉末活性炭的活性污泥法”的高效工艺处理该废水,确定各处理单元的最佳操作参数,系统15d的连续监测数据表明,CODCr,色度和硝基苯的总去除率分别达到85．1％,98．7％和95．9％以上。     

Recognition of bacterial peptidoglycan by the innate immune system

The innate immune system recognizes microorganisms through a series of pattern recognition receptors that are highly conserved in evolution. Peptidoglycan (PGN) is a unique and essential component of the cell wall of virtually all bacteria and is not present in eukaryotes, and thus is an excellent target for the innate immune system. Indeed, higher eukaryotes, including mammals, have several PGN recognition molecules, including CD14, Toll-like receptor 2, a family of peptidoglycan recognition proteins, Nod1 and Nod2, and PGN-lytic enzymes (lysozyme and amidases). These molecules induce host responses to microorganisms or have direct antimicrobial effects.Received 15 January 2003; received after revision 28 February 2003; accepted 26 March 2003     

Thermochemical studies of selenium

By using LKB2277 bioactivity monitor, we have studied the effect of Na₂SeO₃ on Bacillus subtilis Growth at two different media and found the antagonism of protein on its toxicity. Low concentration of Na₂SeO₃ has promoting action, and high concentration of Na₂SeO₃ has inhibitory action. Half inhibitory concentration (IC ₅₀) of BPY medium is 4.2×10⁻¹g/L, andIC ₅₀ of PD medium is 2.2×10⁻²g/L. Supported by the National Natural Science Fundation of China Yan Chengnong: born Apr. 1947, Associate professor. Now work at Jinzhou teachers collage