不同模拟条件下蓝藻甾烷化合物的分布及其对比

现代蓝藻(又称蓝细菌)水压热解生成的有机质与现代蓝藻模拟硅化转化为人工化石生成的有机质,表现出两种相反的甾烷系列化合物分布特征,前者C_(27)甾烷多于C_(29)甾烷,与传统的认识吻合;后者C_(29)甾烷多于C_(27)甾烷,属异常分布,在前寒武纪富藻燧石层样品中也发现C_(29)甾烷多于C_(27)甾烷,特殊的生物来源和热解实验的介质,方法与条件可能是甾烷类生物标志化合物分布特征差异的原因。     

Sodium Acetate Stimulates PHB Biosynthesis in Synechocystis sp. PCC 6803

IntroductionA large variety of bacteria are able to synthesizepolyhydroxyalkanoic acids (PHAs) and to depositlarge amounts of these polyesters as insolubleinclusions in cytoplasm[1 ] . PHAs have attractedthe interest of the chemical industry because oftheir biodegradable properties for applications invarious technical,medical,and pharmaceuticalapplications[2 ] .Poly-β-hydroxybutyrate(PHB) isatypical PHA that is produced by heterotrophicbacteria,such as Alcaligenes eutrophus andEscherichi…     

自养小球藻转化为异养代谢生长后细胞的超微结构与相关生化组成

利用细胞培养技术转化绿色自养的小球藻(Cholrella protothecoides)进行异养生长代谢.酶法分析反映,异养转化过程中细胞培养液中葡萄糖的利用率很高。转化后的细胞光合片层消失,叶绿体同时消失,细胞被一些大的酯肪泡填充,异养藻细胞的细胞壁也比原自养藻细胞加厚,而且细胞表而发生皱缩现象。再次将异养藻细胞置于自养生长条件下,细胞的光合片层和叶绿体结构又得以重建。生化分析显示,经异养转化后藻细胞蛋白质含量下降,为原绿色自养细胞的1/5;相反脂肪含量大幅度增加,是原初的4.4倍,达到细胞干重的72.％。异养藻细胞样品各氨某酸含量都低于自养藻细胞样品,前者以谷氨酸含量较高,后者含甘氨酸最多。在自养藻细胞样品中亚油酸的相对含量最高,为56.50％;转化为异养生长后变成油酸的相对含量占优势,达69.36％,说明异养转作用可明显降低细胞中脂防酸的不饱和程度。     

Distribution and Comparison of Steranes From Blue-Green Algae Under Different Simulated Conditions

Two remarkably opposite distribution patterns of sterane series are revealed from living blue-green alga (or cyanobacterium) under different simulated conditions. The organic matter derived from hydrous-pressure pyrolysis of the blue-green alga is characterised by the predominance of C_(27) sterane over C_(29) sterane; this is coincident with traditional thought. On the contrary, the organic matter derived from artificially silicified microfossils of the blue-green alga is characterised by the predominance of C_(29) sterane over C_(27) sterane; this appears to be an unusual distribution pattern. Such kind of unusual steranedistribution also has been foundin the samples of Precambrian cherts with abundant well-preserved microfossil algae. All these imply that the special source of organisms and the medium, procedure or conditions of simulated pyrolysis may result in the different distribution patterns of sterane biomarkers.     

蓝细菌光系统Ⅱ的组成相关基因和遗传修饰

蓝细菌是研究光合作用的理想实验系统，在光系统Ⅱ组成，相关基因及遗传修饰等分子水平上的探索已取得重大进展，主要介绍了光系统Ⅱ反应中心蛋白复合物，天线色素蛋白复合物，细胞色素蛋白复合物，锰稳定蛋白复合物等主在蛋白成份，相关基因，以及利用分子生物学操作对蛋白组分功能的研究工作。     

Two-Component Signal Transduction Systems in the Cyanobacterium Synechocystis sp. PCC 6803

Introduction Rapid adaptation to environmental challenges is vitally important for bacterial survival and growth. One way in which bacteria control their response to changing environmental conditions is through the mechanism of two-component signal transd…     

聚胞藻热模拟产烃研究

采用ＧＣ和ＧＣＭＳ对蓝藻聚胞藻原生烃类及热解烃类进行了分析．聚胞藻在２５０ ℃～３００ ℃热解产气属于低熟气,以非烃气为主,产气组分参数反映了原核生物母质来源的特征．热解作用使其氯仿沥青“Ａ”含量和烷烃含量大幅度提高．原生烷烃以正烷烃为主,主峰为ｎＣ１７ ．热解烷烃仍以低碳数正烷烃为主,主峰为ｎＣ１７ ,反映了典型的藻类母质来源的烷烃特征．热解烷烃中还检出了丰富的二环倍半萜和五环三萜．五环三萜以Ｃ３０ 莫烷为主峰,并含有丰度较高的Ｃ３０藿烯,表明生成的烃类属于低熟油     

Contributions of DPOR at Low Light Intensi.ty to Chlorophyll Biosynthesis and Growth in the Synechocystis sp. PCC 6803

Introduction Chlorophylls (Chls) and bacteriochlorophylls (Bchls) are two of the most abundant classes of natural pigments, and their biosynthesis is a major metabolic activity in the ecosystem[1]. Protochlorophyllide (Pchlide) is an intermediate in the Chl and Bchl biosynthetic pathway of photosynthetic organisms and its reduction to chlorophyllide (Chlide) is a key regulatory step in the Chl biosynthesis pathway. In this reaction, the porphyrin D-ring of Pchlide is converted to chlorin b…     

New Discoveries in Study on Hydrocarbons From Thermal Degradation of Heterotrophically Yellowing Algae

Green autotrophic alga Chlorella protothecoides contains a very small quantity of hydrocarbons. Heterotrophic culture of this alga results in the cells yellowing, chlorophyll disappearing, protein decreasing and lipid increasing remarkably. The quantities of hydrocarbons from them directly and from the thermal degradation of the cells at or below 200℃ are very low. These hydrocarbons are characterized by predominance of high molecular weight normal alkanes with maximum at C23-C25. When these heterotrophi-cally yellowing cells are thermally degraded at 300℃ , the aliphatic hydrocarbons increase greatly, 32 times that of the green autotrophic ones at the same temperature. Meanwhile, the low molecular weight normal alkanes with C17 as the peak become predominant instead of the original ones of high molecular weight. The actual potential of microplanktonic algae in producing hydrocarbons should be much greater than what people have recognized before.     

Alternative Respiration Induced by Glucose Stimulation and Variation of Adenylate Energy Charge in Glucose-Starved Cells of Green Alga Chlorella Protothecoides

IntroductionCyanide- resistant or alternative respiration hasbeen reported to be widespread in higher plants,phytoplanktons and microorganisms[13 ] . Thestudies of the inhibitor- resistant respiration havecontributed much to the understanding of theorganization and control of complex intracellularrespiratory systems and biochemical processes.Grant and Hommersand[4 ,5] examined theinhibitor- resistantrespiratory characteristics of thegreen alga Chlorella protothecoides grown in highconcentrati…