SEBS分子链在不同溶剂中的荧光特性

利用荧光光谱法对SEBS分子链在不同溶剂中的荧光特性进行了分析。研究表明,室温下,SEBS在四氢呋喃和环己烷中的荧光发射波长为380 nm,且为本征荧光;而在甲苯溶液中的发射波长为375 nm,相对于本征荧光蓝移动了5 nm。在共振散色光谱中,3种体系的共振光强度都是随着溶液浓度的增大呈线性增加,但甲苯溶液体系共振散色光强度的变化较缓慢。造成这些现象的原因在于四氢呋喃和环己烷分子中没有苯环结构,不具备荧光发射的条件,因而SEBS在这两种溶剂中具有本征荧光效应;而甲苯和SEBS都具有苯环结构,相邻的苯环间通过π电子的相互重叠形成T型结构的二聚体,导致了荧光强度的减弱和共振散色光强度变化较缓慢。     

非生物因子对铜绿微囊藻生理代谢影响的研究进展

水体富营养化问题是我国乃至全世界严重的水环境问题,由此而产生的蓝藻水华引起了人们的密切关注。本文综述了蓝藻水华产生中的优势种-铜绿微囊藻在环境中非生物因素影响下其生长繁殖及生理代谢方面的研究进展,揭示了藻体的生长与其环境条件变化的关系,分析了非生物因素对蓝藻群体形成的影响和微囊藻水华发生可能机理,为开展同类工作和微囊藻水华防治工作提供一定的科学依据。     

水华蓝藻控制技术现状及研究进展

蓝藻水华频发严重影响湖库饮用水安全,已成为当前重要的水环境问题。本文通过综述当前国内外主要水华蓝藻控制技术,详细介绍了各种控藻技术方法的优缺点,并就各种技术的使用提出建议和展望,为我国湖库水华蓝藻控制研究提供了理论依据。     

巢湖蓝藻藻蓝蛋白纯化工艺的优化

目的优化巢湖蓝藻藻蓝蛋白的纯化工艺。方法将新鲜蓝藻藻泥经冻融破壁处理,获得藻蓝蛋白粗提液。采取两步盐析及Cellfine A-500阴离子交换层析结合法进行纯化,并以纯度和回收率为检测指标,对一步盐析摩尔浓度(0.8、1.0、1.2、1.4、1.6 mol/L)及二步盐析摩尔浓度(1.6、1.8、2.0、2.2、2.4 mol/L)、阴离子交换层析缓冲液pH(6.0、6.5、7.0、7.5、8.0)、进样浓度(0.418、0.726、1.044、1.288、2.090 mg/L)、洗脱速度(0.5、1、1.5、2、2.5、3.0 cm/min)及洗脱液盐梯度浓度[(0.08、0.10、1.0)、(0.08、0.15、1.0)、(0.08、0.20、1.0)、(0.08、0.25、1.0)、(0.08、0.30、1.0)mol/L]进行优化。同时采用最适条件纯化3批藻蓝蛋白。结果两步盐析的最适摩尔浓度分别为1.0和1.8 mol/L,阴离子交换层析最适条件为缓冲液p H 7.0,进样浓度为1.0～2.0 mol/L,洗脱流速为2 cm/min,洗脱液盐梯度浓度为0.08、0.20、1.0 mol/L。最适条件纯化的3批藻蓝蛋白纯度可达4.0以上,回收率达11%以上。结论成功优化了巢湖蓝藻藻蓝蛋白的纯化工艺,纯化出了试剂级(纯度4.0以上)的藻蓝蛋白。     

青草沙水库水华蓝藻生长的营养盐吸收动力学特征

基于AGP试验原理在青草沙水库原水中添加不同质量浓度的氮磷营养盐,对经过饥饿培养的5种水华蓝藻铜绿微囊藻(Microcystis aeruginosa)、浮颤藻(Planktothrix sp.)、假鱼腥藻(Pseudanabaena sp.)、卷曲鱼腥藻(Anabaena circinalis)、水华束丝藻(Aphanizomenon flos-aquae)进行一次性培养,比较不同蓝藻对添加外源氮磷的生长反应,并应用Monod方程计算了5种藻的营养动力学参数(μ_m、K_s)。结果表明:青草沙水源水库原水对铜绿微囊藻表现出氮限制,对浮颤藻、假鱼腥藻表现出磷限制;氮充足时,青草沙水源水库中铜绿微囊藻易形成优势,氮不足时,假鱼腥藻易形成优势;磷充足时,浮颤藻易形成优势,磷不足时,水华束丝藻易形成优势。综上,控磷除氮可能导致不同水华蓝藻此消彼长。     

藻毒素光化学降解研究取得新进展

蓝藻是我国多数淡水湖泊水华的优势藻种，其代谢产物微囊藻毒素（Microcystins，MCs）在蓝藻细胞破裂或衰老时释放入水中，它能够强烈抑制蛋白磷酸酶的活性，同时还是强烈的肝脏肿瘤促进剂，其对水体环境和人群健康的危害已成为全球关注的重大环境问题之一。     

光照强度对颤藻、小球藻、铜绿微囊藻的生长影响

该文采用颤藻(Oscillatoria sp)、小球藻(Chlorella)和铜绿微囊藻(Microcystis aeruginosa)为研究对象,通过检测叶绿素浓度(Chl-a)关键指标,考察了两种光照条件下(500、1 000 lux)三种藻类生长的规律。同时,利用SLogistic模型对三种藻生长规律进行拟合分析,为预测水华时期不同特征藻类的生长速率、潜能和规律提供参考。     

B-藻红蛋白多层复合薄膜的静电组装及其光谱特性

B-藻红蛋白是一种理想的生物光电材料.利用静电组装技术制备了聚二甲基二烯丙基氯化铵(PDDA)与B-藻红蛋白组装的多层复合薄膜.对薄膜的可见吸收光谱和荧光光谱进行了分析,结果表明:与B-藻红蛋白在溶液中的光谱特征相比,B-藻红蛋白在薄膜上的最大吸收峰由545 nm红移至553 nm,并在573 nm处产生了延迟荧光现象,且薄膜的最大吸光度和光致发射强度均与组装层数呈线性递增关系.随着薄膜组装层数的增加,倒置荧光显微镜能很好地观察到B-藻红蛋白在薄膜上出现明显的聚集体.     

有机溶剂下盐酸环丙沙星的荧光特性研究

本文在几种有机试剂(乙醇，甲醇，丙酮)条件下，对盐酸环丙沙星产生的荧光特性进行了初步的研究，并初步探讨了有机溶剂下温度对其荧光强度的影响。     

极大螺旋藻藻蓝蛋白的提取与纯化

将极大螺旋藻用高渗液低温浸泡、经（ＮＨ４）２ＳＯ４沉淀、透析后,经过改进的羟基磷灰石柱层析２次纯化得到试剂级的藻蓝蛋白。比较了干藻粉在不同高渗液的渗出液条件下藻蓝蛋白的得率和纯度。建立了低温浸泡时ＰＣ得率与纯度和时间的关系。提出了一种简易可行而高效的羟基磷灰尘石制法。     

The release of the blue biological pigment C‐phycocyanin through calcium‐aided cytolysis of live Spirulina sp.

C‐phycocyanin is a light‐harvesting phycobiliprotein found in, amongst other species, the cyanobacterium Spirulina sp. C‐phycocyanin is bright blue in colour and can be used as a natural blue colorant for a variety of applications. Various cell disruption methods exist to cause the lysis of the cyanobacterial cells and release of phycocyanin, but these methods have significant drawbacks, such as cost, difficulty in scale‐up, bacterial contamination, or risk of degrading the protein. This article outlines an alternative method for cell disruption based on the use of Ca(II), which lyses live Spirulina biomass, releasing phycocyanin at a range of concentrations (0.1–0.8 m ) over varying time periods, depending on the conditions. In comparison with other ionic species tested, Ca(II) performed best by a significant margin. Bead milling of biomass was used to quantify the maximum phycocyanin in the biomass, and the greatest was found to be ca. 90% released into solution after 48 h under 0.5 m Ca(II) in a 0.35 m acetate buffer at pH 6. Exposing Spirulina to sodium azide revealed that the mechanism of Ca(II) ion‐aided cytolysis is likely based on a metabolically driven process. This study demonstrates a potential processing option for the release of phycocyanin from live Spirulina, paving the way for the development of a novel bioprocess for the industrial production of the biological pigment.     

纳米TiO_2光催化去除水华藻类的研究进展

由水体富营养化而引起的蓝藻水华是目前全球面临的重大水环境问题,严重威胁水生生态环境以及人类的健康。综述了近年来以TiO_2为代表的纳米材料光催化技术在蓝藻水华治理方面的研究现状,其中光催化负载体技术与可见光响应下高效光催化性能的研究广泛;归纳并总结了TiO_2抑制蓝藻生长光催化机理的一般规律性以及其对蓝藻细胞作用的活性氧(ROS)破坏机制。TiO_2光催化技术未来的发展趋势具有长期可行性,但在实际应用中新型结构单元的高效光催化剂的探索,负载装置应用的完善以及对水体中有害毒素的去除仍然是研究的难题。     

蓝藻生长时变系统非线性动力学分析及水华预测方法

为解决现有蓝藻生长动力学模型难以有效描述实际水体中蓝藻生长时变系统的非线性动力学特性,导致水华预测准确性不高的问题,构建蓝藻摄食和营养盐循环模型,并考虑水温、光照等主要影响因素随时间变化对蓝藻生长的影响,进一步建立蓝藻生长时变系统非线性动力学模型,对其常值参数采用遗传算法与数值算法结合的方法进行优化率定,对其时变参数采用多元时序方法进行建模预测,根据分岔理论及时变系统理论分析水华暴发行为的非线性动力学机理,实现对蓝藻生长时变系统的水华预测。通过太湖流域监测实例表明,与现有研究相比,引入时变参数的蓝藻生长动力学模型更能反映蓝藻生长时变系统下水华暴发行为的非线性动力学特性,其水华预测结果更为准确。     

The Role of Selected Wavelengths of Light in the Activity of Photosystem II in Gloeobacter violaceus

Gloeobacter violaceus is a cyanobacteria species with a lack of thylakoids, while photosynthetic antennas, i.e., phycobilisomes (PBSs), photosystem II (PSII), and I (PSI), are located in the cytoplasmic membrane. We verified the hypothesis that blue–red (BR) light supplemented with a far-red (FR), ultraviolet A (UVA), and green (G) light can affect the photosynthetic electron transport chain in PSII and explain the differences in the growth of the G. violaceus culture. The cyanobacteria were cultured under different light conditions. The largest increase in G. violaceus biomass was observed only under BR + FR and BR + G light. Moreover, the shape of the G. violaceus cells was modified by the spectrum with the addition of G light. Furthermore, it was found that both the spectral composition of light and age of the cyanobacterial culture affect the different content of phycobiliproteins in the photosynthetic antennas (PBS). Most likely, in cells grown under light conditions with the addition of FR and G light, the average antenna size increased due to the inactivation of some reaction centers in PSII. Moreover, the role of PSI and gloeorhodopsin as supplementary sources of metabolic energy in the G. violaceus growth is discussed.     

雨生红球藻的新繁殖方式及其藻蓝蛋白的合成

雨生红球藻(Haematococcus pluvialis)是一种能够合成强抗氧化剂-虾青素的单细胞绿藻,然而由于其生长速率缓慢,制约了虾青素产量的提高。在对雨生红球藻细胞周期的研究中,首次发现了雨生红球藻在高温和低光照条件下的一种特殊繁殖方式,该繁殖方式比已知的营养繁殖和无性繁殖速度快。繁殖过程中厚壁孢子萌发产生大量的小细胞,并且这些小细胞中含有以前在绿藻中从未发现的捕光色素蛋白—藻蓝蛋白(最大吸收波长λmax=621 nm,最大荧光发射波长λmFax=643 nm)。这一发现对于提高天然虾青素的产量和藻蓝蛋白的生产以及藻类的进化有着重要的意义。     

藻蓝素的提取及其光学性质研究

以螺旋藻粉为原料,采用反复冻融法将细胞破碎,然后分别用25%和50%饱和度的硫酸铵溶液盐析等方法制得藻蓝蛋白;用10 mol/L浓盐酸在80℃下处理30 min,破坏了蛋白质与发色团之间的硫醚键,得到游离的发色团-藻蓝素。通过分析产物的紫外可见吸收光谱和荧光光谱了解产物的光学性质,测得所制的产物在660 nm处有荧光;藻蓝素可以溶解在有机溶剂中,在改善有机高分子材料的光学性质方面具有应用价值。     

Deciphering and engineering high-light tolerant cyanobacteria for efficient photosynthetic cell factories

Development and utilization of ‘‘liquid sunshine" could be one of key solutions to deal with the issues of fossil fuel depletion and increasing carbon dioxide.Cyanobacteria are the only prokaryotes capable of performing oxygenic photosynthesis, and their activity accounts for ～25% of the total carbon fixation on earth.More importantly, besides their traditional roles as primary producers, cyanobacteria could be modified as ‘‘photosynthetic cell factories" to produce renewable fuels and chemicals directly from CO_2 driven by solar energy, with the aid of cutting-edging synthetic biology technology.Towards their large-scale biotechnological application in the future, many challenges still need to be properly addressed, among which is cyanobacterial cell factories inevitably suffer from high light(HL) stress during large-scale outdoor cultivation, resulting in photodamage and even cell death, limiting their productivity.In this review, we critically summarized recent progress on deciphering molecular mechanisms to HL and developing HL-tolerant chassis in cyanobacteria, aiming at facilitating construction of HLresistant chassis and promote the future application of the large-scale outdoor cultivation of cyanobacterial cell factories.Finally, the future directions on cyanobacterial chassis engineering were discussed.     

IN SITUMEASUREMENT OF PHOTOCHEMICAL REACTIONS IN MICRODROPLETS

A technique based on fluorescence scattering by microdroplets has been shown to be capable of measuring instantaneous rates of photochemical reactions in microdroplets. The technique has been applied to study trans -to-cis photoisomerization of thioindigo dye in single solution droplets suspended in an electrodynamic balance. Through an analysis it is shown that the concentration distributions of isomers remain uniform in a droplet under the experimental conditions; thus, the scattered fluorescence intensity from the droplet is proportional to the concentration of solely fluorescent trans isomer molecules. The steady-state scattered fluorescence intensity versus incident laser power data have been used to interpret the kinetics of the reaction. The results show that the rate constants can be determined from the scattered fluorescence intensity versus time data. The technique is particularly suitable when only one species fluoresces in the photo-reactive wavelength range while other species present in a droplet do not.     

Mediator toxicity and dual effect of glucose on the lifespan for current generation by Cyanobacterium Synechocystis PCC 6714 based photoelectrochemical cells

BACKGROUND: The capability of cyanobacteria to convert carbon dioxide into carbohydrates offers a promising carbon‐neutral energy solution. Unfortunately, the lifespan of cyanobacteria based photoelectrochemical cells is poor because discharge current drops to zero within days. The primary factor that limits lifespan was believed to be the toxicity of an artificial mediator that extracts electrons from cyanoacteria to electrode. It is critical to experimentally identify the true limiting factor such that we could prolong the lifespan for practical use. RESULTS: Systematic tests on cell physiology and current discharge were performed in autotrophic and heterotrophic conditions. Contrary to previous belief, results for cell viability, chlorophyll content and growth curve of Cyanobacterium Synechocystis PCC 6714 under continuous vitamin K₃‐mediated current discharge did not exhibit any toxic effect. The role of glucose was then investigated. Surprisingly, discharge current dropped to zero although there was significant intracellular glycogen (2.5 × 10^?10 mg cell^?1). Further tests of current response to the addition of exogenous glucose suggest the regulatory role of glucose on cyanobacterial metabolism that is relevant to current generation. Furthermore, current generation in the light and dark conditions corroborates glucose as energy reserve. CONCLUSION: It is not mediator toxicity but the regulatory effect of glucose on the metabolism of cyanobacteria that limits the lifespan for current generation. Glucose functions in a dual role as energy reserve and regulatory molecule to modulate cyanobacterial metabolism related to current generation. Copyright © 2010 Society of Chemical Industry     

Photocatalytic degradation of 17β-oestradiol,oestriol and 17α-ethynyloestradiol in water monitored using fluorescence spectroscopy

Photocatalytic degradation of the natural oestrogens 17β-oestradiol and oestriol and the synthetic oestrogen 17α-ethynyloestradiol in water were investigated. The reactions were carried out in a quartz coil reactor coated internally with titanium dioxide (Degussa P-25). Degradation by UV light alone was also investigated. Reactions were monitored using fluorescence spectroscopy. The effect of initial concentration and the effect of light intensity on the photocatalysis and photolysis of 17β-oestradiol in water were also investigated. The results showed that photocatalysis and photolysis are capable of degrading all three oestrogens in water. Photocatalysis is much more effective than UV light alone and all reactions follow pseudo first order kinetics. The rate was found to be proportional to the square root of light intensity for photocatalysis of 17β-oestradiol. The relationship between light intensity and the rate of degradation by photolysis is linear up to a point when it starts to level off.