野生葛仙米营养成分分析及评价

本文以野生葛仙米为原料,研究了葛仙米营养成分及组成并对其进行营养评价。结果表明:野生葛仙米蛋白质含量达48.61%,含17种氨基酸,其中含人体7种必需氨基酸为44.619%;脂肪酸含量为8.11%,以中碳链为主;富含维生素,VB11.2mg/100g,VB211.8mg/100g,VC550mg/100g,VE7.0mg/100g,β-胡萝卜素114mg/100g,是一种珍稀的食用资源和可开发的蛋白源。     

葛仙米藻蓝蛋白和藻红蛋白的体外抗炎和抗紫外活性比较研究

目的:对葛仙米藻蓝蛋白和藻红蛋白的抗炎和抗紫外活性进行体外比较研究。方法:通过Lipopolysaccharide(LPS)诱导RAW264.7细胞分泌NO和TNF-α,比较葛仙米中藻蓝蛋白和藻红蛋白的抗炎活性;通过Ultraviolet radiation B(UVB)辐照诱导NIH-3T3成纤维细胞损伤,考察藻蓝蛋白和藻红蛋白的抗紫外损伤活性。结果:体外抗炎结果显示LPS能极显著诱导RAW264.7细胞分泌NO和TNF-α(P<0.01),藻蓝蛋白和藻红蛋白均能极显著抑制LPS诱导RAW264.7分泌的NO和TNF-α的含量水平(P<0.01),其中藻红蛋白抑制NO分泌能力高于藻蓝蛋白,藻蓝蛋白对TNF-α的分泌抑制作用高于藻红蛋白。体外抗紫外损伤结果显示UVB 4000 mJ/cm²可以成功诱导NIH-3T3细胞的紫外损伤,但是藻蓝蛋白和藻红蛋白对NIH-3T3细胞的紫外损伤并无明显保护作用。结论:葛仙米中藻蓝蛋白和藻红蛋白具有很好的体外抗炎活性,但两者对UVB诱导的细胞损伤并无明显保护作用。     

Expression of aldehyde dehydrogenase gene increases hydrogen production from low concentration of acetate by Rhodobacter sphaeroides

Rhodobacter sphaeroides RV (RV) is a hydrogen-producing bacterium exhibiting the highest yield of hydrogen production from organic acids such as lactate and acetate, which are the byproducts of hydrogen fermentation by hydrogen-producing anaerobic bacteria. Co-fermentation of the RV strain with anaerobic bacteria is an efficient method of hydrogen production. However, less than 21 mM acetate is produced by the anaerobic bacteria, which is too low for efficient hydrogen production by the RV strain; it requires approximately 75 mM acetate. In this study, 2 distinct isozymes of aldehyde dehydrogenase from Rhodospirillum rubrum were separately overexpressed in the RV strain. The recombinant RV strains that were designated as RVAD1 and RVAD2, exhibited 13-fold higher ALDH activities than the wild-type RV strain. Hydrogen yields of both of the recombinant strains were 1.4-fold higher than that of the RV strain in 21 mM acetate. In 43 mM acetate, the RVAD1 strain showed higher yield, though the RVAD2 strain showed lower yield as compared to that of the RV strain. In 64 mM acetate and all concentrations of lactate tested (21, 43 and 64 mM), the yields of the recombinant strains were lower than those of the RV strain. The intact (empty) expression plasmid increased the ALDH activity and had little effect on the hydrogen production in acetate, however, it decreased the production in lactate. At the beginning of the fermentation process, when very little hydrogen had been produced, the recombinant strains expressing the ALDH gene consumed smaller amounts of acetate compared to the wild-type strain. We have discussed the effects of ALDH on hydrogen production in this report.     

高产辅酶Q10类球红细菌的化学诱变筛选及其发酵培养基优化

利用菌株对（维生素K3+叠氮化钠+对羟基苯甲酸）的复合抗性作为筛选标记,对产辅酶Q10的类球红细菌（Rhodobacter sphaeroides）使用亚硝基胍进行化学诱变,筛选高产菌株并采用响应面法优化其发酵培养基。结果表明,经诱变选育得到一株遗传稳定的辅酶Q10高产菌株R.sp3-7,其最佳发酵培养基组成为：葡萄糖31.7 g/L,玉米浆干粉5.6 g/L,（NH4）2SO4 5.3 g/L、谷氨酸钠 3.0 g/L、NaCl 3.0 g/L、MgSO4·7H2O 12.5 g/L、KH2PO4 3.0 g/L、CaCO3 2.0 g/L、辅液1 mL/L。在此培养条件下,诱变菌株R.sp3-7的辅酶Q10产量达（93.63±0.59） mg/L,与出发菌株相比提高了116.8%。 关键词：中图分类号：TS201.3 文章编号：0254-5071（20１6）06-0090-06 doi:     

球形红细菌降解PNP的不同因素影响及代谢机理

通过拟合Haldane动力学方程,分析球形红细菌(Rhodobacter sphaeroides)H菌株降解对硝基苯酚(PNP)的生长动力学特性;考察营养因素(碳源、金属离子和NaCl浓度)对H菌株降解PNP的影响以及H菌株对酚类物质的底物广谱性,并对H菌株降解PNP的代谢机理进行推测。结果表明,H菌株降解PNP的生长动力学符合Haldane模型(R~2=0.9990);H菌株降解PNP的最适碳源和金属离子分别是苹果酸和Ca~(2+),NaCl浓度耐受值为20 mg·L-1;酚类物质中邻苯二酚对PNP降解影响最大;利用高效液相色谱-质谱联用仪(HPLC-MC)对菌株代谢PNP的产物进行分析,发现中间产物主要为对苯二酚(HQ)、4-羟基粘糠酸半醛(4-HS)和马来酰胺乙酸(MA),同时酶活性分析表明底物HQ在粗酶液中对苯二酚1,2-双加氧酶作用下生成4-HS,由此推测H菌株可能利用的是对苯二酚代谢途径。     

Photoactive Electrodes Incorporating Electrosprayed Bacterial Reaction Centers

Highly efficient light absorption and charge separation within the photosystem and reaction center (RC) complexes of photosynthetic plants and bacteria are of great interest for solar cell and photo detector applications, since they offer almost unity quantum yield and expected ultimate power conversion efficiencies of more than 18% and 12%, respectively. In addition, the charge separated states created by these protein complexes are very long lived compared to conventional semiconductor solar cells. In this work, a novel technique is presented for the deposition of photosynthetic protein complexes, by electrospraying RCs of Rhodobacter sphaeroides onto highly ordered pyrolytic graphite (HOPG) electrodes. Remarkably, it is shown that the RCs not only survive exposure to the high electric fields but also yield peak photocurrent densities of up to 7 μA cm^?2, which is equal to the highest value reported to date.     

Aspects of the metabolism of hydrogen production by Rhodobacter sphaeroides

Photosynthetic bacteria are favorable candidates for biological hydrogen production due to their high conversion efficiency and versatility in the substrates they can utilize. For large-scale hydrogen production, an integrated view of the overall metabolism is necessary in order to interpret results properly and facilitate experimental design. In this study, a summary of the hydrogen production metabolism of the photosynthetic purple non-sulfur (PNS) bacteria will be presented.Practically all hydrogen production by PNS bacteria occurs under a photoheterotrophic mode of metabolism. Yet results show that under certain conditions, alternative modes of metabolism—e.g. fermentation under light deficiency—are also possible and should be considered in experimental design.Two enzymes are especially critical for hydrogen production. Nitrogenase promotes hydrogen production and uptake hydrogenase consumes hydrogen.Though a wide variety of substrates can be used for growth, only a portion of these is suitable for hydrogen production. The efficiency of a certain substrate depends on factors such as the activity of the TCA cycle, the carbon-to-nitrogen ratio, the reduction-state of that material and the conversion potential of the substrate into alternative metabolites such as PHB.All these individual components of the hydrogen production interact and are subject to strict regulatory controls. An overall scheme for the hydrogen production metabolism is presented.     

影响天然混合红螺菌产氢因素的实验研究

研究了以葡萄糖为基质利用天然混合红螺菌生产氢气的影响因素。结果表明，天然混合红螺菌产氢必须在光照、厌氧的条件下进行，在实验范围内较高光强度对天然混合红螺菌的产氢比较有利，并提出天然混合红螺菌产氢的最佳产氢工艺条件，即温度为32℃-40℃，pH值为5—8，接种量为5％～15％。添加有机氮源可使产氢量大幅度提高，天然混合红螺菌在最佳产氢工艺条件下以1％的葡萄糖为基质时的最大产氢量为1．62L／L，具有较好的工程应用前景。