Molecular ecology studies of marine Synechococcus

Cyanobacteria of the genus Synechococcus is a dominant component of microbial community in the world's oceans, and is a major contributor to marine primary productivity and thus plays an important role in carbon cycling in the oceans. Besides the ecological importance, the cultivability also made Synechococcus a very special group of marine microorganisms, which has attracted great attention from oceanographers and biologists. Great progress in the physiology, biochemistry and phylogeny of Synechococcus has been made since its discovery. We here review the current status of molecular ecology of marine Synechococcus and give a perspective into the future based on our understanding of the literature and our own work.     

The genome of a motile marine Synechococcus

Marine unicellular cyanobacteria are responsible for an estimated 20-40% of chlorophyll biomass and carbon fixation in the oceans. Here we have sequenced and analysed the 2.4-megabase genome of Synechococcus sp. strain WH8102, revealing some of the ways that these organisms have adapted to their largely oligotrophic environment. WH8102 uses organic nitrogen and phosphorus sources and more sodium-dependent transporters than a model freshwater cyanobacterium. Furthermore, it seems to have adopted strategies for conserving limited iron stores by using nickel and cobalt in some enzymes, has reduced its regulatory machinery (consistent with the fact that the open ocean constitutes a far more constant and buffered environment than fresh water), and has evolved a unique type of swimming motility. The genome of WH8102 seems to have been greatly influenced by horizontal gene transfer, partially through phages. The genetic material contributed by horizontal gene transfer includes genes involved in the modification of the cell surface and in swimming motility. On the basis of its genome, WH8102 is more of a generalist than two related marine cyanobacteria.     

运用COBRA方法研究聚球藻代谢网络

生物过程的系统级建模和模拟,在定量和动态获得细胞功能方面具有指导作用。利用基于约束的代谢网络分析方法在计算机中模拟细胞代谢,分析聚球藻代谢网络的基本拓扑结构和网络内在联系。通过对代谢网络中的反应进行逐一删除,使用FBA和FVA方法分析敲除反应后的代谢网络的流量分布,以及该反应的敲除对其余反应的影响,并找到代谢网络中对整个系统有影响的反应,进一步验证其网络理论和模型方法的可行性。     

对虾白斑病毒VP28基因在聚球藻中的表达与分析

通过PCR从实验室保存的pMD-VP28质粒中扩增得到对虾白斑病毒囊膜蛋白VP28基因,同时在设计的引物起始密码子前添加促进外源基因在蓝藻中表达的SD序列,引物末端添加限制性内切酶住点BamH I和EcoR I,从质粒pRL-439获得强启动子PpsbA,酶切连接构建了pDC-VP28高效表达穿梭裁体.利用三亲接合转移成功地将构建的栽体pDC-VP28转化聚球藻7002.对转基因聚球藻进行培养,其表达产物通过SDS-PAGE分析,发现表达量达3%左右.     

HCO3 - 高亲和转运蛋白操纵子基因在聚球藻7942 CO2浓缩机制中功能的研究

蓝藻 Synechococcus sp.PCC7942 HCO3 - 高亲和转运蛋白操纵子基因 cmpABCD 是其CO2浓缩机制中的调控基因之一.本研究用携带潮霉素B磷酸转移酶基因(hygromycin B pho transferase, hpt) 筛选标记的同源双臂整合载体pUC-HATH转化蓝藻Synechococcus sp.PCC7942,以潮霉素B作为筛选试剂筛选出具潮霉素B抗性的转化藻,运用引物PCR方法证实潮霉素B磷酸转移酶基因表达盒通过质粒pUC-HATH的介导已定点插入蓝藻 Synechococcus sp.PCC7942 基因组中,成功地构建了具有潮霉素B抗性的cmpBCD 基因插入失活突变藻株.并最终通过比较野生藻Synechococcus sp.PCC7942 和突变藻Synechococcus sp.PCC7942 在不同 Na2CO3浓度的改良BG-11培养基中生长特性,探讨了HCO3 -高亲和转运蛋白操纵子 cmpABCD 基因失活对藻体生长的影响.     

海洋蓝细菌(聚球菌属,Synechococcus)的生态学意义及研究方法

综述了海洋蓝细菌(聚球菌属,Synechococcus)的生态学意义和国际上研究海洋蓝细菌的方法和技术, 以及我国研究海洋蓝细菌的现状和我们的一些研究工作。     

铁限制诱导对聚球藻转录组的影响

为探究Fe元素限制对聚球藻转录组的影响,该文以聚球藻Synechococcus sp.PCC 7002为研究对象,采用高通量测序技术对经过铁限制处理的聚球藻Synechococcus sp.PCC 7002进行转录组分析.以铁的3种摩尔浓度进行处理,其中每组数据重复3次实验,一共获得9组实验数据;对照组摩尔浓度为10....     

Omics in marine biotechnology

Marine biotechnology emerged in the 1980s, and since then it has been gradually gaining momentum to meet growing demands that cannot be satisfied by terrestrial sources alone.     

从喜温蓝藻分离热稳定限制性内切核酸酶

从喜温蓝藻ＳｙｎｅｃｈｏｃｏｃｕｓｅｌｏｎｇａｔｕｓＴ３分离出一种限制性内切核酸酶，命名为ＳｅｌＩ．此酶是限制性内切核酸酶Ｓａｕ９６Ｉ的同切酶，它们的识别序列ＧＧＮＣＣ．但是ＳｅｌＩ的反应条件与Ｓａｕ９６Ｉ不同．ＳｅｌＩ是一种热稳定的限制性内切核酸酶，最适反应温度的范围是５０～５７℃     

开发海洋能源，建设海洋强国

海洋能源开发是海洋强国建设的重要支撑。论述了近年来科技创新为海洋能源勘探开发做出的巨大贡献,提出了中国海洋能源开发未来的主攻方向及建议:加大近海非常规油气开发技术攻关,为中国油气工业提供更多现实的贡献;加大深海油气勘探开发力度,打造中国油气产业未来的重要接替区;突破天然气水合物规模化开发关键技术,早日实现商业化开采;打造深海能源开发装备舰队,支撑海洋强国建设;抢占先机,布局并推进大洋矿产的勘探开发;进一步加强极地科研攻关,深度参与极地开发。     

一种喜温蓝藻的培养条件

从厦门杏林湾温泉分离到一种喜温蓝藻Ｓｙｎｅｃｈｏｃｏｃｃｕｓｅｌｏｎｇａｔｕｓｖａｒ．ａｍｐｈｉｇｒａｎｕｌａｔｕｓＣｏｐｅｌａｎｄ（Ｓ．ｅｌｏｎｇａｔｕｓＴ３）．测定了该蓝藻的培养条件．培养基ＢＧ－１１以ｐＨ７．５为宜，若添加１．２ｍｍｏｌ／Ｌ的碳酸氢钠对该蓝藻生长有利；接种量控制在接种后培养液中的细胞密度２×１０６ｃｅｌｌ／ｍＬ较好；适於生长的培养温度和光照强度分别为５５℃和２５００Ｌｘ．经计算，这种蓝藻的细胞倍增时间为６．９ｈ．     

Crystal structure of photosystem II from Synechococcus elongatus at 3.8 A resolution

Oxygenic photosynthesis is the principal energy converter on earth. It is driven by photosystems I and II, two large protein-cofactor complexes located in the thylakoid membrane and acting in series. In photosystem II, water is oxidized; this event provides the overall process with the necessary electrons and protons, and the atmosphere with oxygen. To date, structural information on the architecture of the complex has been provided by electron microscopy of intact, active photosystem II at 15-30 A resolution, and by electron crystallography on two-dimensional crystals of D1-D2-CP47 photosystem II fragments without water oxidizing activity at 8 A resolution. Here we describe the X-ray structure of photosystem II on the basis of crystals fully active in water oxidation. The structure shows how protein subunits and cofactors are spatially organized. The larger subunits are assigned and the locations and orientations of the cofactors are defined. We also provide new information on the position, size and shape of the manganese cluster, which catalyzes water oxidation.     

Methane-consuming archaebacteria in marine sediments

Large amounts of methane are produced in marine sediments but are then consumed before contacting aerobic waters or the atmosphere. Although no organism that can consume methane anaerobically has ever been isolated, biogeochemical evidence indicates that the overall process involves a transfer of electrons from methane to sulphate and is probably mediated by several organisms, including a methanogen (operating in reverse) and a sulphate-reducer (using an unknown intermediate substrate). Here we describe studies of sediments related to a decomposing methane hydrate. These provide strong evidence that methane is being consumed by archaebacteria that are phylogenetically distinct from known methanogens. Specifically, lipid biomarkers that are commonly characteristic of archaea are so strongly depleted in carbon-13 that methane must be the carbon source, rather than the metabolic product, for the organisms that have produced them. Parallel gene surveys of small-subunit ribosomal RNA (16S rRNA) indicate the predominance of a new archael group which is peripherally related to the methanogenic orders Methanomicrobiales and Methanosarcinales.     

发展海洋监测高新技术振兴海洋仪器行业

本文概述了我国海洋监测技术和仪器设备的发展现状,提出了建立和发展适合我国国情的海洋环境监测系统的必要性和重要性,从海洋监测系统建设、海洋仪器研制开发等方面分析了发展海洋监测新技术,振兴海洋仪器行业的意义以及必须解决的具体问题。     

口服转胸腺素α1基因聚球藻对小鼠T细胞亚群作用的研究

为探讨口服后转胸腺α1(Tα1)基因聚球藻对T细胞亚群的作用,将小鼠随机分为空白对照组、野生藻组、转化藻(小剂量、中剂量和大剂量)组和日达仙组,用灌服的方式,给予空白对照组20mL·kg~(-1)的生理盐水,野生藻组0.4g·kg~(-1)的野生聚球藻;转化藻小、中、大剂量组,分别0.2g·kg~(-1)、0.4g·kg~(-1)和0.6g·kg~(-1)的转Tα1基因聚球藻;日达仙组则肌注给予3.2mg·kg~(-1)的胸腺素α1(日达仙)。结果表明转Tα1基因藻口服后可显著提高CD3亚群水平,显著提高CD4亚群水平,明显提高CD4/CD8的比值。提示转Tα1基因聚球藻具有增强机体免疫功能的作用。     

海事领域的发证问题(英文)

证书是船舶依从相关规定及公约的证明.船旗国有责任通过调查和发证来确定悬挂该国国旗的船舶切实履行了相关公约的责任和义务.根据由海事局与认可组织所达成一致的授权程度,海事局与船级社或者两者同时都可以履行发证的职责.通过对一些原因的阐述来解释为什么海事局和船级社都应该履行发证的职权.