极端嗜盐菌冻干保藏及其质检稳定性的研究

采用优化组合保护剂冷冻干燥２０株极端嗜盐菌，于４℃冷库保存２年，经复水测定，全部菌株保持较高存活性．用ＴＥＮＳ法对其中９株菌Ｒ１，ＲＦ１，Ｊ７，Ｓ９，Ｔ４～１，Ｊ６，Ｒ６～１，Ｒ６～７和Ｒ６～５作质粒稳定性检测，含质粒的菌株ＲＦ１，Ｊ７，Ｓ９，Ｔ４～１，Ｒ６～５于４℃保存２年后，质粒稳定存在；而菌株Ｒ１，Ｊ８，Ｒ６～１和Ｒ６～７冻干保存前后均末检测到质粒．结果表明：优化组合保护剂不仅能有效地用于极端嗜盐菌的冷冻干燥保藏，还能保持宿主质粒的稳定性．     

鸡土从菌的小白球菌阶段培养初探

通过模拟实验来研究鸡纵菌的小白球阶段的培养条件.结果表明小白球菌除需要低 p H值 (4.0一4.5) 和低浓度有机氮外,还需要多种维生素和一定的糖类,小白球菌在实验 室条件下生长良好,液体培养已获得成功,为人工利用和栽培鸡纵菌提供了一 条 可能的 途径     

Purification and Characterization of Cold-active α-Amylase Excreted by A Strain of Marine Cold-adaptive Penicillia

The filamentous fungi from the Huanghai sea sludge were screened according to their ability to produce cold-active α-amylase. The strain with the highest amylase activity was identified as Penicilllum species. The α-amylase purified by ammonium sulphate precipitation and column chromatography on DEAE-sepharose and sephadex G-100 shows a molecular weight of about 55000 and a pl of 4. 38. The enzyme is stable in a pH range of 5.5—8.0 and has a maximum activity at pH 6.0. Compared with the α-amylase from mesophiles and thermophiles, the cold-active enzyme shows a high enzyme activity at lower temperatures and a high sensitivity at temperatures higher than 50℃. The optimal temperature is 40℃ and the activity decreases dramatically at temperatures above 50℃. Ca^2 shows a significant effect on maintaining the structure and the activity of the enzyme. EDTA and Cu^2 are its inhibitors. The products from the hydrolysis of soluble starch with the cold-active enzyme are maltose and other oligosaccharides.     

Dynamic Behaviour of Self-Diffraction in Bacteriorhodopsin Film

We investigate the dependences of the diffraction efficiency of the first order self-diffracted beam in bacteriorhodopsin (bR) films on the illumination time, the intensity and wavelength of the incident light. When the blue light (λ = 488 nm) and low intensity red light (λ = 632.8 nm) are incident on the bR film respectively,the diffraction efficiencies increase from zero to a stable value with the illumination time. When the green light (λ = 533 nm) and high-intensity red light illuminate the bR film respectively, the diffraction efficiencies increase from zero to the maximum and then decrease to a stable value with the illumination time. Rise and decay times are dependent on the intensity and wavelength of the incident light. The maximal diffraction efficiency of the red light is twice as high as that of the green light. The highest diffraction efficiency of 5.4% is obtained at 633nm.The diffraction efficiency change with the time for the green light is larger than that for the blue and red light.     

竹红菌甲素光敏氧化吲哚类化合物的研究 I: 关于色氨酸光敏氧化机制的初步探讨

本文利用吸收光谱、荧光光谱和闪光光解研究了竹红菌甲素和色氨酸的相互作用.通过猝灭实验、氘代效应和溶剂效应探讨了竹红菌甲素敏化的色氨酸光氧化机制, 证明该反应是以单重态氧过程为主, 并辅以电子转移的机制. 另外, 考察了反应条件对反应的影响, 发现底物浓度、溶解氧浓度、溶剂的性质和溶液的PH值均对反应有很大的影响.     

竹红菌甲素光敏氧化反应机制

本文报道了在竹红菌甲素的光敏氧化反应中,原初反应产生了~1O_2、O_2~-和H_2O_2,在一些还原性底物(5-羟基色氨酸、色氨酸、组氨酸、蛋氨酸和赖氨酸等)的存在下,体系中形成的O_2~-量大大增加。证明了体系中的~1O_2是通过三重态的竹红菌甲素和基态氧进行能量传递形成的,O_2~-是体系中的竹红菌甲素负离子自由基和基态氧进行单电子转移的结果,H_2O_2是体系中存在的竹红菌甲素二价负离子还原基态氧的产物。在一些底物存在下,次级反应产生了·OH。我们也发现竹红菌甲素具有弱的抽氢能力而生成一些有机自由基,这些有机自由基的形成促进了各种活泼态氧的相互转化,因此我们认为竹红菌甲素的光敏氧化是各种活泼态氧和一些有机自由基综合反应的结果。     

某些还原性生物分子对竹红菌甲素敏化产生^1O~2的抑制作用

存在还原性的生物分子如甲硫氨酸、尿酸和 还原性谷胱甘肽时,竹红菌甲素经受单电子还原形成甲素的半醌自由基、在去氧溶液中观察到了 甲素半醌负离子自由基的ESR信号.在充氧的溶液中检测到了超氧负离子自由基.还原剂的存在降低了单重态氧的生成并引起超氧负离子自由基的生成.     

蕨藻红素（Caulerpin）的结构分析

蕨藻红素分子的化学计量式为Ｃ_（２４）Ｈ_（１８）Ｎ_２Ｏ_４，用Ｘ－ｒａｙ法确定其晶体结构。该结晶呈紫红色，属单斜晶系，空间群为Ｃｃ。晶胞参数：ａ＝１９．６１２（４），ｂ＝４．７６３（１），ｃ＝２０．４３４（５）Ａ，β＝８１．８３（２）°，Ｚ＝４，Ｖ＝１８８９．４（７）Ａ~３，Ｄ_ｃ＝１．４１５ｇ·ｃｍ~（－３），Ｆ（０００）＝８３２。应用直接法解析分子结构。以最小二乘法修正结构参数。最终可靠因子Ｒ＝０．０５４，Ｒ_ω＝０．０６３。结果表明蕨藻红素分子是具有非晶体学Ｃ_２对称性的吲哚生物碱。     

单重态氧化学 VI: 胶束中竹红菌甲素诱导的二苯基异苯并呋喃光敏氧化反应动力学

本文研究了增溶于胶束内部的HA诱导的DPBF光敏氧化动力学。测定了DPBF在不同胶束中光敏氧化总速率常数, 分别为5.12×10^9(SDS), 2.31×10^9(Triton X-100)和6.21×10^9L/mol.s(TDPB)。实验证明胶束可有效猝灭单重态氧却不猝灭HA的激发三重态, 从而导致DPBF光敏氧化双分子反应可按假一级动力学规律处理, 可求出表观速率常数为1.52×10^-^3s^-^1(SDS)或1.54×10^-^3s^-^1(Triton X-100), 相应的半寿命为7.5min, 这些结果为HA在水溶液中的光动态行为的研究提供了依据。     

固定化对恶臭假单胞菌腈水合酶催化特性的影响

酶法代替铜催化法使丙烯腈转化制内烯酰胺的研究,70年代起在国外开始进行.近年来,国内也相继开展了这方面的工作.他们筛选得到的恶臭假单胞菌JP-1具有较高腈水合酶活力,其完整细胞的腈水合酶催化特性也已进行了研究.本文研究了采用海藻酸钙包埋法制备的恶臭假单胞菌固定化细胞的酶学性质.