UVB-induced photodamage to phycobilisomes of Synechococcus sp. PCC 7942

The effect of UVB irradiation on the phycobilisomes (PBSs) of Synechococcus sp. PCC 7942 cells was studied. The sucrose density-gradient-isolated PBSs from in vivo UVB-treated (280–320 nm) cells showed a strong decrease in β-phycocyanin (βPC) and -phycocyanin (PC) polypeptides. In addition to a decrease in the linker polypeptides LCM 75 (linker connecting the core to the thylakoid membranes), LR 33 (linker in the rod structure), LRC 31.5 (linker connecting the rod to the core) and LRC 29. In vitro UVB treatment of gradient-isolated intact PBSs for 1 h had no effect on any of the constituent polypeptides, and only after 2 h was a degradation of LCM 75 and LR 33 and a decrease in βPC evident. Further investigation of phycobiliproteins (4 h of UVB irradiation) using polyclonal antibody directed against purified whole PBSs revealed that, in vivo, there was a gradual decline in the levels of LCM 75, LR 33, LRC 31.5, LRC 29, βPC and PC.     

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。     

The Influence of Metabolic Inhibitors,Antibiotics, and Microgravity on Intact Cell MALDI-TOF Mass Spectra of the Cyanobacterium Synechococcus Sp. UPOC S4

The aim and novelty of this paper are found in assessing the influence of inhibitors and antibiotics on intact cell MALDI-TOF mass spectra of the cyanobacterium Synechococcus sp. UPOC S4 and to check the impact on reliability of identification. Defining the limits of this method is important for its use in biology and applied science. The compounds included inhibitors of respiration, glycolysis, citrate cycle, and proteosynthesis. They were used at 1–10 μM concentrations and different periods of up to 3 weeks. Cells were also grown without inhibitors in a microgravity because of expected strong effects. Mass spectra were evaluated using controls and interpreted in terms of differential peaks and their assignment to protein sequences by mass. Antibiotics, azide, and bromopyruvate had the greatest impact. The spectral patterns were markedly altered after a prolonged incubation at higher concentrations, which precluded identification in the database of reference spectra. The incubation in microgravity showed a similar effect. These differences were evident in dendrograms constructed from the spectral data. Enzyme inhibitors affected the spectra to a smaller extent. This study shows that only a long-term presence of antibiotics and strong metabolic inhibitors in the medium at 10⁻⁵ M concentrations hinders the correct identification of cyanobacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF).     

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....     

Chemical environment heterogeneity around the two chlorophyll a′ molecules in photosystem I

Treatment of whole and fractionated plant tissues with hydrophilic and hydrophobic solvent mixtures of varied volume ratio liberates two chlorophyll (Chl) a′ molecules from the photosystem (PS)I core when the solvent hydrophilicity exceeds a critical level, whereas only one molecule is extracted in hydrophobic media. The PSI core proteins, PSI-A and PSI-B, which form a heterodimer, appear to bind one Chl a′ molecule each, in local environments significantly different regarding their hydrophilicity or hydrophobicity.     

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.     

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℃     

外源基因的导入对Synechococcus sp.PCC7942 SOD活性和同工酶谱的影响

外源DNA导入Synechococcus sp．PCC7942后．通过NBT光化还原和PAGE电泳检测发现转基因藻Synechococcus sp．PCC7942的SOD活性和同工酶谱发生了改变．若外源基因整合在受体细胞染色体DNA上，根据整合位点的不同则能提高或减弱Synechococcus sp．PCC7942的SOD活性，同时增加同工酶谱带．若外源基因不是整合在染色体上而是以质粒的形式存在，则只改变Synechococcus sp．PCC7942 SOD活性而不影响其同工酶谱．     

Glutamate production from CO2 by Marine CyanobacteriumSynechococcus sp.

A photobioreactor was constructed in the form of a Perspex column 900 mm tall with an internal diameter of 70 mm. The reactor volume was 1.8 L and the light source consisted of a metal-halide lamp to reproduce sunlight. Light was distributed through the culture using a new type of optical fiber that diffuses light out through its surface, perpendicular to the fiber axis. A cluster of 661 light-diffusing optical fibers (LDOFs) pass from the light source through the reactor column (60-cm culture depth) and are connected to a mirror at the top of the reactor. This biosolar reactor has been used for the production of glutamate from CO₂ by the marine cyanobacterium Synechococcus sp. NKBG040607. We present here details of the construction of the biosolar reactor and characterization of its properties. The effect of light intensity on glutamate production was measured. Carbon dioxide-to-glutamate conversion ratios were determined at different cell densities: the maximum conversion ratio (28%) was achieved at a cell density of 3x10⁸ cells/mL. A comparison of glutamate production using the LDOF biosolar reactor described here with production by batch culture using free or immobilized cells showed that use of an optical-fiber biosolar reactor increased glutamate-production efficiency 6.75-fold. We conclude that as a result of its high surface-to-volume ratio (692/m) increased photoproduction of useful compounds may be achieved. Such a system is generally applicable to all aspects of photobiotechnology.     

3种淡水藻类对三唑磷的富集行为研究

比较了具有代表性的3种淡水藻类--莱因衣藻(Chlamydomonas reinhardtii)、纤细裸藻(Euglena gracilis)和聚球藻(Synechococcus leopoliensis)对三唑磷的富集行为,在初始浓度为10μg穖L-1的条件下,3种藻对三唑磷的富集在极短的时间内达到平衡,富集量分别达到63.2、88.0和45.4μg穏-1(湿重),并对藻体富集三唑磷的机理以及引起这3种藻类富集行为差异的可能原因进行了初步探讨.