红假单胞菌的分离鉴定与生长特性

由青岛沿岸潮间带表层沉积物分离出４株光合细菌，经鉴定属于荚膜红假单胞菌和球形红假单胞菌。光照厌氧培养生长实验表明ＨＤ３的最适盐度为Ｓ＝１５－２５，ＰＳ２－２为一淡水菌株。菌株ＨＤ３的最适ＰＨ范围为６．３５－８．３。ＨＤ３、ＲＳ均不能利用硫化物且其生长受较高浓度的硫化物抑制。     

浑球红假单胞菌的卟啉分泌与调节

对浑球红假单胞菌（Ｒｐｓ．ｓｐｈａｅｒｏｉｄｅｓ）Ｐ４菌株的卟啉合成与分泌进行了研究．经过在ＲＣＶＢ培养基中的增殖生长与产卟啉液ＭｉｘｔｕｒｅＩ中的诱导，Ｐ４菌可以产生较高含量的卟啉．通过研究分析各种外界因子对卟啉合成与分泌的影响，确定了有利于Ｐ４菌合成与分泌卟啉的培养条件，包括光照、适当的底物浓度、较低的Ｆｅ２＋浓度以及培养程序和培养时间等．为进一步研究菌叶绿素和细菌色素代谢机理、为Ｐ４菌用于卟啉生产提供了良好的基础．     

碳源对浑球红假单胞菌P4株氧化—还原反应平衡的影响

本文采用浑球红假单胞菌Ｐ４株作为研究对象，分析了光合细胞在厌氧光照条件下：①利用乙醇或乙酸为碳源时，对ＣＯ２依赖性的差异；②利用乙醇为碳源时，氢气发生量与添加ＣＯ２浓度的关系；③利用一些有机碳源时，氢气发生量与碳代谢中的关键酶活性的变化。从而阐明了光合细菌利用不同碳源时，实现细胞内氧化－还原反应平衡的复杂调控机制。     

红假单胞菌的生理学特性研究

对经过鉴定均属于红假单胞菌属的四个菌株^[5]的生理特性作了系统研究，结果表明：各菌株在光照厌氧条件下可利用多种低分子有机酸、醇类和部分糖类，适宜的氮源有铵盐、谷氨酸和蛋白胨；经计算机寻优，其最适初始pH值为7．0—7．5；不同菌株对NaCl的耐受情况有所不同；酵母膏对菌株P—15N、P—16的生长有明显的刺激作用。     

沼泽红假单胞菌类胡萝卜素的提取和分析

对沼泽红假单胞菌B．9菌株（Rhodopseudomonas Palustris strain B.9)类胡萝卜素的提取进行了研究。用超声波破碎菌体,类胡萝卜素得量较高;菌体中类胡萝卜素用丙酮提取,提取效果因菌体量,丙酮用量而变,提取液经萃取,皂化,洗涤得类胡萝卜素粗制品,对其分析表明B．9菌株含有螺菌黄素系列的类胡萝卜素。     

红假单胞菌的分离及菌种保存试验研究

从不同来源的样品中分离出四株光合细菌 ,经鉴定均属于红假单胞菌 ,同时分别采用液体种自然条件下、液体种蜡封、穿刺物蜡封、砂土管等方法对其菌种进行了保存试验研究 ,最后得出两种最佳保存方法 :蜡封液体试管种法和试管穿刺蜡封法     

沼泽红假单胞菌固氮酶活性的调节

本文研究了沼泽红假单胞菌谷氨酰胺合成（简称ＧＳ）对其固氮酶活性的调节。外源氨的加入迅速抑制固氮酶活性，同时ＧＳ被高度腺苷酰化，随着氨的消耗，固氮酶活性逐渐恢复，ＧＳ腺苷酰化程度也逐渐降低。ＧＳ专一的不可逆抑制剂甲硫氨酸亚砜亚胺（简称ＭＳＸ）可以解除氨和谷氨酰胺对固氮酶的抑制作用。     

沼泽红假单胞菌的分离鉴定及对重金属铜的响应的研究

从自然水体中分离到一株光合细菌并对其进行鉴定.对光合细菌施加不同浓度Cu2+的影响进行了研究.从信阳市南湾水库大坝下层底泥取样,分离纯化到的红色菌株在显微镜下观察,及生化试验后初步鉴定为一株光合细菌.根据16SrRNA的保守序列设计的常用光合细菌引物.PCR扩增DNA片段大小约为400bp,挑选菌液测序.结果在BLAS...     

一株产CoQ10的红假单胞菌的研究

从滇池分离到一株革兰氏阴性杆菌，于光照厌氧及黑暗好氧条件下生长良好，活细胞在870、803nm处有吸收峰，具平行片层状的光合内膜系统，可归属于红假单胞菌属（Rhodopseudomonas)；该菌体中提取分主了得到的黄色结晶品，经Craven试验、高效薄层层析、高效液相色谱、紫外光谱、红外光谱、核磁共振及质谱证实，为CoQ10。     

利用球形红细菌降低小麦、油菜幼苗中镉积累的研究

采用水培试验,研究了光合细菌球形红细菌（Rhodobacter sphaeroides）菌液对重金属镉胁迫下小麦（Triticum aestivum）和油菜（Brassica campestris）幼苗生长及富集镉的效应.结果表明,镉的添加浓度为0.5 mg/L、10 mg/L、20 mg/L,菌液的浓度为35 mg/L、70 mg/L（湿重）时,小麦和油菜幼苗生长受到的镉抑制都有不同程度的缓解,几项生长指标都有一定的增长,其中小麦茎叶长度,根系长度和鲜重的增长率范围依次为3.16%～11.26%、2.46%～6.85%、11.34%～65.82%;油菜相应的增长率为0.98%～14.71%,5.80%～34.42%,3.93%～27.63%;加入菌液后两种植物各部分镉积累也有不同的程度的降低,小麦茎叶,根系,整株镉的降低率范围依次为8.30%～16.36%、3.78%～31.70%、3.38%～15.04%;油菜相应的降低率为1.05%～12.30%、50.59%～58.48%、0.89%～25.19%.同浓度镉处理下,加入菌液与未加入菌液的处理之间存在差异.     

葛仙米生长及繁殖条件的探讨

以葛仙米为原料，探讨了在实验室自养培养时电导率、pH、温度、M／P等对葛仙米生物量的影响．测定结果为：葛仙米的生物量随着电导率的减小呈递增状态，但是当培养液电导率减小到320mΩ/cm时，葛仙米生物量开始下降．pH过低或过高，均会影响葛仙米的生长及颜色，随pH升高，葛仙米自身的颜色会加深，直至pH升至7．5．随着Ca^2 浓度的提高，葛仙米的生物量增加，当Ca^2 浓度为0．032g/L时，生物量达最高值．当ρN／ρP为1：1时葛仙米的生长速度较快且生物量较高．确定葛仙米的最适培养条件为：温度10～30℃，pH为6～7．5，光照时间为每昼夜11h．     

光周期对葛仙米生长和光合系统活性的影响

通过设置光暗比(L∶D)24h∶0h、12h∶12h和8h∶16h三个光周期处理组,对葛仙米(Nostoc sphaeroides Kutzing)依次开展了三个批次的培养,测定光周期对葛仙米生长和光合活性的影响.结果表明,24h连续光照对葛仙米生长具有显著抑制作用,不适合应用于葛仙米的长期连续批量培养中.3个光周期处理组中,葛仙米叶绿素荧光Fv/Fm在第一个培养批次中降低,但是很快都在第二个和第三个培养批次中得到缓和.葛仙米PS捕光天线色素含量的变化表明,葛仙米能够通过下调该色素的含量来降低较长光照对葛仙米光合系统的光抑制和破坏,从而获得较高的光合作用效率.     

微氧条件下厌氧颗粒污泥和消化污泥特性研究

用12 5mL血清瓶作为批量处理反应器,对厌氧颗粒污泥和消化污泥在厌氧和微氧条件下的COD去除率、污泥产率、产甲烷活性、抗冲击负荷能力等进行对比实验研究。实验结果表明:厌氧颗粒污泥和消化污泥均在微氧条件下表现出高COD去除率、低污泥产率、高产甲烷活性和强抗冲击负荷能力,且厌氧颗粒污泥在COD去除率、污泥产率、产甲烷活性和抗冲击负荷等方面更具有优势;对于0 5 gCOD/LR·d的有机负荷,反应器内最佳加氧量为10mL(10 %添加的COD)。     

Excited-state dynamics in light-harvesting complex of Rhodobacter sphaeroides

Photodynamics of peripheral antenna complexes, light-harvesting complex （LH2） of Rhodobacter （Rb） Sphaeroides 601, was studied using femtosecond pump-probe technique at different laser wavelengths. The obtained results reveal dramatic dynamical evolutions within B800 and B850 absorption bands of antenna complexes LH2. At excitation wavelength around 835 nm, a sharp photobleaching signal was observed which was assigned to the contribution of the two-exciton state, which was further confirmed by the power dependence measurement. Rate equations with eight-level scheme were used to calculate the population evolution in LH2 and the transient dynamics under femtosecond pulse excitation. The research results prove that not only the transition from ground state to one-exciton state but also that from one-exciton state to two-exciton state contribute to the photodynamics of B850.     

Excited-state dynamics in light-harvesting complex of Rhodobacter sphaeroides

Photodynamics of peripheral antenna complexes,light-harvesting complex (LH2) of Rhodobacter (Rb) Sphaeroides 601,was studied using femtosecond pump-probe technique at different laser wavelengths. The obtained results reveal dramatic dynamical evolutions within B800 and B850 absorption bands of antenna complexes LH2. At excitation wavelength around 835 nm,a sharp photobleaching signal was observed which was assigned to the contribution of the two-exciton state,which was further confirmed by the power dependence measurement. Rate equations with eight-level scheme were used to calculate the population evolution in LH2 and the transient dynamics under femtosecond pulse excitation. The research results prove that not only the transition from ground state to one-exciton state but also that from one-exciton state to two-exciton state contribute to the photodynamics of B850.     

葛仙米中SOD基因的克隆及在大肠杆菌中的表达

采用PCR技术从葛仙米（Nostoc sphaeroides）总DNA中克隆了一段基因序列,该序列与基因库中已公布的编码普通念珠藻（Nostoc commnue）超氧化物歧化酶的氨基酸序列同源性为98％,将该基因插入含T7启动子的质粒pET-32a（＋）中构建表达质粒pET-sod,然后将该表达质粒转入大肠杆菌BL21中进行蛋白表达,表达菌株用lmmol／L1PTG诱导表达数小时后,产生较多重组的蛋白,且该蛋白以可溶性蛋白形式存在,SDS-PAGE分析表明：在相对分子量约为22kd的位置有一条明显蛋白质带,将诱导表达后的蛋白通过亲和层析的方法进行蛋白纯化;NBT光还原法测定表达产物的比活力,每毫克纯化蛋白约为2550U。     

Colony development and physiological characterization of the edible blue-green alga, Nostoc sphaeroides (Nostocaceae, Cyanophyta)

The edible blue-green alga,Nostoc sphaeroides Kützing,is able to form microcolorties and spherical macrocolonies.It has been used as a potent herbal medicine and dietary supplement for centuries because of its nutraceutical and pharmacological benefits.However,lim-ited information is available on the development of the spherical macrocolonies and the environmental factors that affect their structure.This report described the morphogenesis of N.Sphaeroides from single trichomes to macrocolonies.During the process,most structural features of macrocolonies of various sizes were dense maculas,rings,the compact core and the formation of liquid core;and the filaments within the macrocolonies showed different lengths and arrays depending on the sizes of macrocolonies.Meanwhile temperature and light intensity also strongly affected the internal structure of macrocolonies.As microcolonies further increased in size to form 30 mm mac-rocolonies,the colonies differentiated into distinct outer,middle and inner layers.The filaments of the outer layer showed higher max-imum photosynthetic rates,higher light saturation point,and higher photosynthetic efficiency than those of the inner layer;whereas the filaments of the inner layer had a higher content of chlorophyll a and phycobiliproteins than those of the outer layer.The results obtained in this study were important for the mass cultivation of N.Sphaeroides as a nutraceutical product.     

Comparison of the Photosynthetic Characteristics of Two Developmental Stages in Nostoc sphaeroides Kutzing （Cyanophyta）

The photosynthetic activities between two main developmental stages, colony and hormogonium, of the edible cyanobacterium Nostoc sphaeroides Kutzing, were compared. Hormogonia have a higher content of chlorophyll than that of colonies. It showed that the ratios of phycocyain （PC）, allophycocyain （APC） and phycoerythrocyanin （PEC） in hormogonia and colonies were different. The room temperature chlorophyll fluorescence, 77 K chlorophyll fluorescence, measurements of PSⅠand PS Ⅱ activities all showed that colony has higher photosynthetic competence than hormogonia. Hormogonia had a higher respiration rate than colony, while their maximum photosynthetic oxygen evolution rates were very close. The responses of hormogonia and colonies to high light illuminations also were different. Both of their oxygen evolution rates decreased quickly with the prolonged high light illumination, but hormogonia can keep relatively higher PSⅡ activity （Fv/Fm） than that of colonies. The results suggested that colony was photosynthetically more competent than hormogonia, while the ability of hormogonia to tolerate high light illumination was higher than that of colony.     

固氮细菌─植物根际联合固氮作用的研究进展

固氮细菌与植物根际的联合固氮作用是目前研究的热点之一．本文在查阅和整理大量资料的基础上,对目前国内外此项研究的情况作了一个简单的概括．介绍了联合固氮作用的测定方法：分析了联合固氮作用的影响因素;并着重介绍了几种联合固氮体系（包括宿主与固氮菌两个方面）．本文还注意到联合固氮作用的研究已不限于禾本科植物,木本科植物的根际联合固氮作用也已被发现．