A new model of phycobilisome in Spirulina platensis

Phycobilisomes (PBS) were isolated from blue-green algaSpirulina platensis. Scanning tunneling microscope was used to investigate the three-dimensional structure of PBS deposited on freshly cleaved highly oriented pyrolytic graphite (HOPG) in ambient condition at room temperature. The results showed that the rods of PBS radiated from the core to different directions in the space other than arrayed in one plane, which was different from the typical hemi-discoidal model structure. The diameter of PBS was up to 70 nm, and the rod was approximately 50 nm in length. Similar results were observed in Langmuir-Blodgett (LB) film of PBS. The dissociated PBS could reaggregate into rod-like structures and easily form two-dimensional membrane while being absorbed on HOPG, however, no intact PBS was observed. The filling-space model structure of PBS inSpirulina platensis with STM from three-dimensional real space at nanometer scale was found, which showed that this new structural model of PBS surely exists in blue-green algae and red algae. The function of this structural model of PBS was also discussed.     

A new model of phycobilisome inSpirulina platensis

Phycobilisomes (PBS) were isolated from blue-green algaSpirulina platensis. Scanning tunneling microscope was used to investigate the three-dimensional structure of PBS deposited on freshly cleaved highly oriented pyrolytic graphite (HOPG) in ambient condition at room temperature. The results showed that the rods of PBS radiated from the core to different directions in the space other than arrayed in one plane, which was different from the typical hemi-discoidal model structure. The diameter of PBS was up to 70 nm, and the rod was approximately 50 nm in length. Similar results were observed in Langmuir-Blodgett (LB) film of PBS. The dissociated PBS could reaggregate into rod-like structures and easily form two-dimensional membrane while being absorbed on HOPG, however, no intact PBS was observed. The filling-space model structure of PBS inSpirulina platensis with STM from three-dimensional real space at nanometer scale was found, which showed that this new structural model of PBS surely exists in blue-green algae and red algae. The function of this structural model of PBS was also discussed.     

Molecular replacement studies on crystal structure of allophycocyanin from red algae Porphyra yezoensis

Using the crystal structure of allophycocyanin from cyanobacterium Spirulina platensis (APC-SP) as a search model,the crystal structure of allophycocyanin from red algae Porphyra yezoensis (APC-PY) has been studied by molecular replacement methods.The APC-PY crystals (Form 3) belong to the space group of R32,cell dimensions a=b= 10.53 nm,c=18.94 nm,α= β= 90°,γ=120°;there is one αβ monomer in each crystallographic asymmetric unit in the cell.The translation function search gave a unique peak with a correlation coefficient (Cc) of 67.0% and an R-factor of 36.1% for reflection data from 1.0 to 0.4 nm.Using the results by molecular replacement,the initial model of APC-PY was built,and the coincidence of the chromophore in APC-PY initial model with its 2Fo-Fc OMIT map further confirms the results by molecular replacement.     

钝顶螺旋藻生物富集Cr(Ⅲ)影响因素的研究

对钝顶螺旋藻生物富集Cr(Ⅲ)的影响因素进行了研究。发现螺旋藻对Cr(Ⅲ)的生物富集主要经历了快速的吸附和缓慢的吸收两个步骤;化学键较弱的Cr(Ⅲ)化合物具有较高的富集效率;藻细胞浓度一定时,随着Cr(Ⅲ)浓度的增加,单位重量螺旋藻对Cr(Ⅲ)的富集量不断增加,最后趋于饱和;当Cr(Ⅲ)浓度一定时,随着藻细胞浓度的增加,螺旋藻对Cr(Ⅲ)的总富集量逐渐增加而单位重量藻体的富集量减少。研究还证实,螺旋藻干粉比新鲜藻能富集更多的Cr(Ⅲ);pH值是影响Cr(Ⅲ)生物富集的一个重要影响因素,最佳pH在7左右;温度升高和加强光强均可加强Cr(Ⅲ)的富集;阳离子对Cr(Ⅲ)的富集存在一定的促进或抑制作用。     

微量元素锗对四种微藻光合色素的影响

采用溶液培养方法,以锗作为胁迫因子,研究了锗对４种微藻“钝顶螺旋藻（Ｓｐｉｒｕｌｉｎａ ｐｌａｔｅｎｓｉｓ）、盐生杜氏藻（Ｄｕｎａｌｉｅｌｌａ ｓａｌｉｎａ）、淇江叉鞭金藻（Ｄｉｃｒａｔｅｒｉａ ｚｈａｎｊｉａｎｇｅｎｓｉｓ）和微绿藻（Ｎａｎｎｏｃｈｌｏｒｏｐｓｉｓ．ｓｐ）光合色素的影响。实验结果表明,经１０ｍｇ／ｄｍ＾３锗处理后,四种藻类细胞中的光合色素都发生了较大变化,有些色素发生明显的增加或     

Photoinhibition induced alterations in energy transfer process in phycobilisomes of PS II in the cyanobacterium, Spirulina platensis

Exposure of algae or plants to irradiance from above the light saturation point of photosynthesis is known as high light stress. This high light stress induces various responses including photoinhibition of the photosynthetic apparatus. The degree of photoinhibition could be clearly determined by measuring the parameters such as absorption and fluorescence of chromoproteins. In cyanobacteria and red algae, most of the photosystem (PS) II associated light harvesting is performed by a membrane attached complex called the phycobilisome (PBS). The effects of high intensity light (1000-4000 micromol photons m(-2) s(-1)) on excitation energy transfer from PBSs to PS II in a cyanobacterium Spirulina platensis were studied by measuring room temperature PC fluorescence emission spectra. High light (3000 micromol photons m(-2) s(-1)) stress had a significant effect on PC fluorescence emission spectra. On the other hand, light stress induced an increase in the ratio of PC fluorescence intensity of PBS indicating that light stress inhibits excitation energy transfer from PBS to PS II. The high light treatment to 3000 micromol photons m(-2) s(-1) caused disappearance of 31.5 kDa linker polypeptide which is known to link PC discs together. In addition we observed the similar decrease in the other polypeptide contents. Our data concludes that the Spirulina cells upon light treatment causes alterations in the phycobiliproteins (PBPs) and affects the energy transfer process within the PBSs.     

Spectroscopic properties of the C-phycocyanin-allophycocyanin conjugate and the isolated phycobilisomes from Spirulina platensis

C-phycocyanin (CPC) and allophycocyanin (APC) were purified from Spirulina platensis, then the CPC was attached covalently to the APC by reacting their ∈-amino groups. The excitation energy could be transferred from the CPC to the APC in the CPC-APC conjugate. Intact phycobilisomes (PBS), consisting of CPC, APC, colourless linker polypeptides, and APC B or Lcm, were isolated from S. platensis. Spectroscopic properties of the isolated PBSs kept at 20 °C for various times showed that the connection between the APC and the APC B or Lcm was looser than that between the CPC and the APC in the isolated PBSs. The CPC-APC conjugate was more stable than the isolated PBSs, and the linker polypeptides had a minor influence on the excitation energy transfer characteristic between different phycobiliproteins in the PBS.     

Probing connection of PBS with the photosystems in intact cells of Spirulina platensis by temperature-induced fluorescence fluctuation

Temperature-dependent fluorescence for intact cells of cyanobacterium Spirulina platensis was detected to search for the connection of the phycobilisome (PBS) with Photosystem I (PSI) and Photosystem II (PSII). Some interesting results were obtained from the deconvoluted fluorescence components of C-phycocyanin (C-PC), allophycocyanin (APC), PSI and PSII as well as the fluorescence spectra of the intact cells at room temperature (RT=25 degrees C) and 0 degrees C. It was observed that, compared to those at RT, both of the fluorescence components for PSI and APC increased, whereas those for PSII and C-PC decreased at 0 degrees C with excitation at 580 nm, that is, the fluorescence for C-PC is not synchronous with that for APC, and the fluorescence fluctuation for PSI is not synchronous with that for PSII. On the other hand, the decrease in C-PC fluorescence is synchronous with the increase in PSI fluorescence, and the increase in APC fluorescence is synchronous with the decrease in PSII fluorescence. Therefore, it can be readily deduced that PBS should be coupled not only with PSII through the terminal acceptors in the APC core but also with PSI through C-PC in PBS rods at physiological condition, while at 0 degrees C, a migration of a PBS makes the APC partially detached from PSII but the C-PC more efficiently coupled with PSI. The results provide good evidences for "mobile PBS" model and "parallel connection" model but not for the "spillover" model.     

Spectroscopic properties of the C-phycocyanin-allophycocyanin conjugate and the isolated phycobilisomes from Spirulina platensis

C-phycocyanin (CPC) and allophycocyanin (APC) were purified from Spirulina platensis, then the CPC was attached covalently to the APC by reacting their ∈-amino groups. The excitation energy could be transferred from the CPC to the APC in the CPC-APC conjugate. Intact phycobilisomes (PBS), consisting of CPC, APC, colourless linker polypeptides, and APC B or Lcm, were isolated from S. platensis. Spectroscopic properties of the isolated PBSs kept at 20 °C for various times showed that the connection between the APC and the APC B or Lcm was looser than that between the CPC and the APC in the isolated PBSs. The CPC-APC conjugate was more stable than the isolated PBSs, and the linker polypeptides had a minor influence on the excitation energy transfer characteristic between different phycobiliproteins in the PBS. This revised version was published online in June 2006 with corrections to the Cover Date.     

Environmental Impacts of Large-Scale Spirulina (Arthrospira platensis) Production in Hellisheidi Geothermal Park Iceland: Life Cycle Assessment

Marine Biotechnology - Spirulina algae (Spirulina platensis) cultivated in geothermally powered photobioreactors is here proposed as a potentially resource efficient, zero-carbon, and nutritious...     

钝顶螺旋藻富硒培养条件的优化

硒是人和动物必需的微量元素 ,补硒可以防治多种疾病。有机硒具有低毒、高生物利用度的优点 ,目前主要寄希望于生物转化的途径来获得有机硒[1 ] 。植物对硒的生物有机化作用已有综述[2 ] ,并开发有富硒酵母[3 ] 、富硒菇类[4] 、富硒大蒜、富硒黄芪、富硒西洋参、富硒麦芽、富硒茶以及富硒鸡蛋、富硒牛奶等[5] 。螺旋藻是一种很有开发利用前景的藻类 ,但其含硒量极微 ,实验报道富硒螺旋藻对60 Ｃｏ γ射线胸部照射大鼠诱发肺炎和早期肺、肝纤维增生有防治作用[6] 。在培养液中添加亚硒酸钠可以实现藻类对硒的富集和转化 ,而且螺旋藻对无机硒…     

活体微藻吸附水体中Cd2+的性能特征

【目的】藻类对重金属吸附和吸收是重金属进入食物链的重要渠道之一。研究活体微藻对水体中Cd~(2+)的吸附性能和吸附机理,旨在为Cd~(2+)等重金属离子进入水体后的去向及去除提供理论依据。【方法】选取地表水普遍存在的4种微藻:钝顶螺旋藻(Spirulina platensis)、铜绿微囊藻(Microcystis aeruginosa)、四尾栅藻(Scenedesmus quadricauda)和小球衣藻(Chlamydomonas microsphaera)作为试验材料,通过室内模拟实验,利用Langmuir、Freundlich和Dubinin-Radushkevich(D-R)3种等温吸附模型,研究4种活体微藻对Cd~(2+)的吸附规律及吸附参数。【结果】4种微藻对水体Cd~(2+)吸附均可以用Langmuir、Freundlich和D-R模型描述,其中用Langmuir模型拟合钝顶螺旋藻、Freundlich模型拟合小球衣藻、D-R模型拟合铜绿微囊藻和四尾栅藻的吸附效果最佳。四尾栅藻对Cd~(2+)的吸附量最高,而钝顶螺旋藻对Cd~(2+)的吸附量最低,但与Cd~(2+)的亲和力最强,4种微藻吸附Cd~(2+)主要是以离子代换为主的化学吸附。【结论】微藻对Cd~(2+)均有较强的吸附能力,会引起以微藻为食的水生动物Cd~(2+)富集;微藻也是去除水体Cd~(2+)的潜在吸附剂原料。     

不同生境下的钝顶螺旋藻RAPD分析

本文对不同生境下的钝顶螺旋藻Spirulina (Arthrospira) platensis进行了RAPD分析。结果表明, 鄂尔多斯高原碱湖和Chad湖的钝顶螺旋藻基因组DNA扩增多态性片段同源性为 48.23%。2 个样品在分子遗传水平上存在着较大的差异, 这是由于各自生态环境明显不同和长期地理隔离造成的。     

钝顶螺旋藻C—藻蓝蛋白分子的STM研究

钝顶螺旋藻Ｃ┐藻蓝蛋白分子的ＳＴＭ研究张玉忠＊１,２时东霞１周百成２曾呈奎２庞世瑾１（１中国科学院北京真空物理实验室,北京２７２４信箱,北京１０００８０）（２中国科学院海洋研究所,青岛２６６０７１）关键词钝顶螺旋藻;Ｃ－藻蓝蛋白;扫描隧道显微镜藻胆蛋...     

FtsZ在钝顶螺旋藻形态建成中的作用

为了研究细胞骨架蛋白FtsZ在螺旋藻形态建成中的作用,通过PCR克隆了ftsZ基因并进行原核表达,对表达的融合蛋白进行了纯化。通过免疫小鼠制备了FtsZ的多克隆抗体。分别用Western blot和免疫荧光技术检测螺旋藻不同形态藻丝体中ftsZ的表达和定位。结果表明,在两株不同螺旋藻Spirulina platensisFACHB869和FACHB882中,ftsZ在直线形藻丝体中的表达量都高于螺旋形藻丝体。免疫荧光定位结果显示,FtsZ蛋白在藻细胞中呈环状分布于细胞膜上,且这种环状结构在直线形藻丝体中排列较密而在螺旋形藻丝体中排列疏松。ftsZ在不同形态藻丝体中的表达量和细胞定位差异说明,细胞骨架蛋白FtsZ可能通过改变细胞刚性而参与螺旋藻形态建成。     

不同生境下的钝顶螺旋藻RAPD分析

本文对不同生境下的钝顶螺旋藻Spirulina(Arthrospira)platensis进行了RAPD分析.结果表明,鄂尔多斯高原碱湖和Chad湖的钝顶螺旋藻基因组DNA扩增多态性片段同源性为48.23%.2个样品在分子遗传水平上存在着较大的差异,这是由于各自生态环境明显不同和长期地理隔离造成的.     

Comparative evaluation of the vitamin composition of unicellular algae and higher plants grown under artificial conditions

The vitamin composition of representatives of green (Chlorella vulgaris, Platimonas viridis), blue-green (Synechococcus elongatus, Coccopedia, Spirulina platensis, Cyanidium caldarium), red (Porphyridium cruentum) unicellular algae and higher plants (wheat, chufa, beet, carrot, turnip, radish, cucumber, dill, Welsh onion, potato) grown under artificial conditions was examined. The content of B complex vitamins (thiamine, riboflavine, nicotinic and folic acids), ascorbic acid and carotene was measured. Among the algae studied Chlorella vulgaris and Spirulina platensis showed the highest vitamin activity. The red alga Porphyridium cruentum contained the lowest quantity of thiamine, riboflavine and carotene and larger amounts of nicotinic acid. Comparison of the content of vitamins C, B1, B2, PP, folic acid and carotene in unicellular algae and higher plants, that are natural and traditional sources of the vitamins, demonstrated that the above green and blue-green algae contain greater than higher plants amounts of thiamine, riboflavine, folic acid and carotene, when calculated per g dry matter. All algae, except for Platimonas viridis and Cyanidium caldarium, are superior to beet and carrot in their content of ascorbic acid and inferior to green vegetables (radish, cabbage, dill and Welsh onion) in that parameter.     

Light-induced excitation energy redistribution in Spirulina platensis cells: "spillover" or "mobile PBSs"?

State transitions induced by light and redox were investigated by observing the 77 K fluorescence spectra for the intact cells of Spirulina platensis. To clarify if phycobilisomes (PBSs) take part in the state transition, the contributions of PBSs to light-induced state transition were studied in untreated cells and the cells treated by betaine which fixed PBSs firmly on the thylakoid membranes. It was observed that the betaine-treated cells did not show any light-induced state transition. This result definitely confirmed that the light-induced excitation energy regulation between the two photosystems is mainly dependent on a spatial movement of PBSs on the thylakoid membranes, which makes PBS cores partially decoupled from photosystem II (PSII) while PBS rods more strongly coupled with photosystem I (PSI) during the transition from state 1 to state 2. On the other hand, an energy exchange between the two photosystems was observed in both untreated and betaine-treated cells during redox-induced state transition. These observations suggested that two different mechanisms were involved in the light-induced state transition and the redox-induced one. The former involves only a physical movement of PBSs, while the latter involves not only the movement of PBS but also energy spillover from PSII to PSI. A model for light-induced state transition was proposed based on the current results as well as well known knowledge.     

Te(Ⅳ)胁迫对两种螺旋藻生长及抗氧化酶系统的影响

在钝顶螺旋藻(Spirulina platensis)和极大螺旋藻(Spirulina maximum)接种的第5天至第10天添加不同浓度的亚碲酸钠,研究Te(Ⅳ)胁迫对两种螺旋藻的生长、抗氧化活性系统和脂质过氧化作用的影响。结果表明,通过调节添加碲的时间,可以有效地调节碲胁迫强度,随着加碲时间依次后移,碲胁迫强度逐渐减小,螺旋藻的最终生物量递增。碲对螺旋藻的生物效应与碲胁迫强度有关,也与添加碲时藻所处的生长期有关。实验组Ⅲ(分别在第7、8、第9天三天添加碲)的碲胁迫强度并不是最低的,两种螺旋藻的最终生物量也不是最大,但MDA的含量却是最低的,表明该实验组的生长状态是最佳的。各种抗氧化酶(SOD、GPX、CAT、APX和POD)的活性变化情况较复杂。其中,在碲胁迫下,GPX的活性显著提高。       

碳酸盐碱度对钝顶螺旋藻生长的影响

研究了不同碳酸盐碱度浓度条件下,钝顶螺旋藻OD560值、藻液pH值及碳酸盐碱度的变化。结果显示:培养4d后,4mg/L和8mg/L组生长缓慢且呈现下降趋势,OD560值均低于对照组,具有极显著差异(P<0.01),16mg/L和32mg/L组与对照组相比,无显著差异,而64mg/L组具有显著差异(P<0.05)。第6~12d,4mg/L、8mg/L组和16mg/LOD560值均低于对照组,具有极显著差异(P<0.01),32mg/L组无显著差异,而64mg/L组在6~8d,具有显著差异(P<0.05),且在第10~12d,与其它实验组和对照组相比,表现出极显著差异性(P<0.01)。NaHCO3与Na2CO3组成的缓冲体系,其pH值调节功能优于单一使用NaHCO3的对照组。在充气状态下,实验期间各组的碱度始终保持动态平衡。