甲磺隆对水华鱼腥藻的抑制效应

将高效低毒的除草剂用于处理日趋严重的水华问题，系统地研究了甲磺隆对水华鱼腥藻生长的效应，获得了十分显著的抑藻效果，并发现了甲磺隆抑藻作用的特点，明确了用其抑藻的最适使用浓度及务件，为使用除草剂杀灭和抑制藻类提供了依据及可行的方法。     

3种磺酰脲除草剂对水华鱼腥藻的生长效应

采用分光光度法比较研究了甲磺隆、氯磺隆和苄嘧磺隆3种磺酰脲除草剂对水华鱼腥藻的生长效应。发现3种药剂都对一定初始浓度的水华鱼腥藻有抑制生长的作用,并得到了抑制作用规律。     

甲磺隆对水华鱼腥藻作用机理初探

以水华鱼腥藻的乙酰乳酸合成酶（ALS）比活力作为研究对象,通过在离体和活体条件下比较其对甲磺隆的敏感性,探讨了甲磺隆对水华鱼腥藻的作用机理.结果表明：离体条件下,甲磺隆对水华鱼腥藻ALS抑制强烈,且浓度越高抑制作用越强,其IC50=0.026mg/L;活体条件下,当甲磺隆的浓度为0.001mg/L时,甲磺隆对水华鱼腥藻ALS几乎没有抑制作用,这可能是甲磺隆在水华鱼腥藻体内被降解失活的缘故.当甲磺隆的浓度为0.01～10mg/L时,甲磺隆对水华鱼腥藻ALS抑制与离体条件下的抑制作用基本一样,其IC50=0.714mg/L.     

单嘧磺隆对不同小麦品种的耐药性研究

以主根长为指标，研究了5个小麦品系对磺酰脲类除草剂单嘧磺隆的敏感性，比较了单嘧磺隆对它们的乙酰乳酸合成酶（简称ALS）在离体条件下的活性的影响。研究表明单嘧磺隆对不同小麦品种的耐药能力与其ALS的敏感性无关。     

滦河水的除藻实验研究

该文针对滦河源水进行了杀藻的试验研究。研究结果表明：对引滦水而言,硫酸铜、高锰酸钾和过氧化氢三种杀藻剂的藻类去除率均随药剂投量的增加而升高;在原水含藻量较高（高于1000万个／L）情况下,硫酸铜较佳投量1．0mg／L,藻类去除率为70％～80％;过氧化氢投量4mg／L,藻类去除率为60％左右;高锰酸钾投量0．6mg/L,藻类去除率为85％;通过杀藻效果、经济性以及安全性等方面的综合比较,对于以有毒蓝藻为优势藻的引滦水,三种杀藻剂的优劣排序为：高锰酸钾〉硫酸铜〉过氧化氢。     

壳聚糖凝聚去除景观水中微囊藻的研究

考察了壳聚糖原位除藻的效果及可行性。对pH范围为5．5-7．0,藻浓度大于5．0×10^5cells／mL的模拟含藻水,壳聚糖投加量与藻浓度比大于0．5mg：（106cells／mL）、壳聚糖投加量〉0．5g／m3时,0D650去除率可以达到90％以上。而对相同藻浓度的实际景观水,当壳聚糖投加量与藻浓度比大于0．8mg：（10^6cells／mL）、壳聚糖投加量〉0．8g/m3时,OD650去除率可以达到80％以上。通过现场围隔实验．研究了壳聚糖凝聚除藻与遮光工艺相结合的处理效果,即投加壳聚糖凝聚沉淀藻细胞后进行遮光处理,使沉入水底的藻类由于失去光源而不再上浮,逐渐死亡。与无遮光处理围隔组对照,发现除藻效果有明显提升,显示了该工艺的可行性。     

鱼腥藻 Anabaena sp. PCC7120的混合营养生长

在高光强为１６０μＥ／（ｍ２·ｓ）、低光强为１６μＥ／（ｍ２·ｓ）、葡萄糖浓度０～３０ｇ／Ｌ范围内,、进行了鱼腥藻Ａｎａｂａｅｎａｓｐ．ＰＣＣ７１２０的摇瓶光自养和混合营养培养．在高光强下最大藻细胞密度（０．９２～３．１ｇ／Ｌ）明显高于低光强（０．１１～０．５８ｇ／Ｌ）,而且高光强使混合营养培养的对数期缩短．在不同光强下,葡萄糖浓度在０～１８ｇ／Ｌ范围内提高显著促进了细胞的生长,在１８～３０ｇ／Ｌ范围内变化对细胞生长不再有更大的影响．高光强促进了藻细胞对葡萄糖的利用．在高光强下随着葡萄糖浓度的提高,细胞得率逐渐变小．     

杜邦的两个磺酰脲除草剂在美国获应用范围扩大批准

杜邦开发的以磺酰脲为基质，用于与草甘膦桶混在耐草甘膦玉米中进行应用的两个除草剂已在美国获得批准。它们是①Require Q（砜嘧磺隆6．3％＋麦草畏52．9％）和②Resolve Q（砜嘧磺隆18．4％＋噻吩磺隆4％）。它们对多种禾木科杂草和阔叶杂草可提供触杀和残留防治效果，对耐草甘膦杂草也提供可靠的管理效果。由于上述两种除草剂中均含有安全剂双苯嗯唑酸，从而使得它能在多种玉米杂交品种虫应用。Resolve Q的推荐用量为0．9公斤／公顷，而Require Q的用量为4盎司／英亩。     

甲嘧磺隆对两种滩涂动物的急性致毒试验

本文生要研究了甲嘧磺隆对鲈鱼、蛏两种主要的滩涂养殖生物进行了急性毒性研究,为甲嘧磺隆用于滩涂防治互花米草提供科学依据。结果表明：处理96h后对于鲈鱼和蛏的半致死浓度（LC50）分别为151．322和374．450mg／L,甲嘧磺隆对两种实验动物急性毒性属于低毒,对于两种滩涂养殖动物在急性毒性方面没有明显影响。     

超高效液相色谱-串联质谱测定谷子、植株和土壤中的单嘧磺隆残留

[目的]单嘧磺隆是我国创制的谷子田内吸型磺酰脲类除草剂,在谷子田应用前景广阔。采用超高效液相色谱串联质谱法(UPLC-MS/MS)建立了谷子、植株和土壤中单嘧磺隆的残留检测方法,并测定了收获期的残留量,为单嘧磺隆的安全使用提供技术支撑。[方法]谷子、植株和土壤中的单嘧磺隆残留采用纯乙腈振荡提取,C18和GCB净化,UPLC-MS/MS检测,外标法定量。[结果]在0.0025～0.1 mg/L质量浓度范围内,单嘧磺隆质量浓度与其峰面积之间呈现出良好线性关系,R2≥0.9984。在0.005、0.01、0.1 mg/kg添加水平,单嘧磺隆在谷子、植株和土壤中的回收率在69%～96%范围内,相对标准偏差低于12.1%,符合农药残留分析的要求。田间条件下,按照推荐剂量施用10%单嘧磺隆可湿性粉剂,收获期谷子、植株和土壤中单嘧磺隆残留均低于方法的定量限(LOQ,0.005 mg/kg)。[结论]10%单嘧磺隆可湿性粉剂按照推荐剂量施用收获期安全。本试验可以为单嘧磺隆的安全使用和最大残留限量(MRL)的制定提供基础数据。     

水华鱼腥藻超弱发光光谱研究

利用BPCL微弱发光测量仪首次系统地研究了蓝藻门中的水华鱼腥藻发射超弱发光光谱,研究发现水华鱼腥藻的超弱发光光谱在440 nm和575 nm处有特征峰出现。     

Biodegradation Capability and Enzymatic Variation of Potentially Hazardous Polycyclic Aromatic Hydrocarbons—Anthracene and Pyrene by Anabaena fertilissima

This study encompasses the biodegradation capacity of Anabaena fertilissima to model PAH (Polycyclic Aromatic Hydrocarbon) compounds namely Anthracene (ANT) and Pyrene (PYR) at different LC₅₀ concentrations viz., 5.0 mg/L and 3.0 mg/L, respectively, on growth in terms of Chlorophyll-a and protein. Depletion in chlorophyll-a and protein content was registered with rise in PAHs concentration while the inhibition of nitrogen fixing enzymes such as nitrate reductase and glutamine synthetase activity was also concentration dependent and showed more sensitivity for high molecular weight aromatic compound PYR as compared to ANT. GC/MS analysis explained the degradation of ANT by 46% and PYR by 33%, at 5.0 mg/L and 3.0 mg/L, respectively. Moreover, the common degraded product for ANT was 2, 4-Dimethyl-1-heptene and for PYR it was 2, 3, 4-Trimethylhexane. Results indicate that PYR was more stable and recalcitrant compared to ANT. This study suggests that Anabaena fertilissima could be used for bioremediation of ANT and PYR pollution in surface waters and terrestrial environments.     

鱼腥藻7120中异形胞发育的影响因子

以鱼腥藻7120为对象,考察了碳源浓度和种类、氮源浓度和种类、光强及NaCl浓度对鱼腥藻7120异形胞发育及发生频率的影响. 结果表明,NaNO3和NH4Cl都会抑制异形胞的分化,NaNO3对异形胞的抑制可以通过提高CO2浓度而解除,但NH4Cl的抑制作用是彻底的;而添加NaHCO3却不能在NO3-存在时诱导鱼腥藻产生异形胞;提高光强和NaCl浓度能够增加异形胞的比例. 证明了胞内碳氮比例的升高是异形胞分化的直接原因.     

蓝细菌鱼腥藻7120混合营养培养的生长和生理特征

Mixotrophic growth is one potential mode for mass culture of microalgae and cyanobacteria particularly suitable for the production of high value bioactive compounds and fine chemicals.The typical heterocystous cyanobacterium Anabaena sp.PCC 7120 was grown in the presence of exogenous glucose in light.Glucose improved the cell growth evidently,the maximal specific growth rate under mixotrophic condition(0.38 d1)being 1.6-fold of that of photoautotrophic growth.Mixotrophy caused a variation in cellular pigment composition,increasing the content of chlorophyll a and decreasing the contents of carotenoid and phycobiliprotein relative to chlorophyll a.Fluorescence emission from photosystem II(PSII)relative to photosystem I was enhanced in mixotrophic cells,implying an increased energy distribution in PSII.Glucokinase(EC 2.7.1.2)activity was further induced in the presence of glucose.The mixotrophic culture was scaled up in a 15 L airlift photobioreactor equipped with an inner and an outer light source.A modified Monod model incorporating the specific growth rate and the average light intensity in the reactor was developed to describe cell growth appropriately.The understanding of mixotrophic growth and relevant physiological features of Anabaena sp.PCC 7120 would be meaningful for cultivation and exploitation of this important cyanobacterial strain.     

Redundant pathways of sunscreen biosynthesis in a cyanobacterium

Route of the sun block: according to empirical evidence, sun-screening mycosporine-like amino acids (MAAs) in Eukarya originate from the shikimic acid pathway, whereas in cyanobacteria, biosynthesis of the MAA shinorine reportedly occurs through the pentose phosphate pathway. However, gene deletion shows that the cyanobacterium Anabaena variabilis ATCC 29143 does not biosynthesise shinorine exclusively by this route.     

Large‐scale isolation and purification of C‐phycocyanin from the cyanobacteria Anabaena marina using expanded bed adsorption chromatography

BACKGROUND: Phycobiliproteins are water soluble proteins useful as fluorescent markers of cells and macromolecules, and as natural colorants, and are anticarcinogenic. Although phycobiliproteins have many applications, their use is limited by the high cost of the purified macromolecules, mainly related with the cost of extraction and purification. In this study a fast and scalable method for preparative extraction and purification of C‐phycocyanin (C‐PC) from Anabaena marina is developed. RESULTS: The method developed consists in the extraction of phycobiliproteins using repeated single contact strategy, separation being performed by expanded bed adsorption (EBA) chromatography using Streamline‐DEAE. Optimal conditions for EBA were obtained at small scale, using a 15 mm internal diameter column, these being a sample load of 0.9 mg C‐PC mL^?1 adsorbent, an expanded bed volume twice the settled bed volume and a sample viscosity of 1.109 mP. The process was then scaled up 36 times, the success of the scale‐up process being verified. Finally, to obtain pure C‐PC conventional ion‐exchange chromatography was utilized. CONCLUSION: Small diameter columns was shown to be useful to simulate the behavior of larger diameter columns for use in scaled up systems. Expanded bed adsorption was demonstrated to be a scalable technology allowing large quantities of C‐PC to be obtained, maintaining high protein recovery while reducing both processing cost and time. The proposed methodology allows recovery of more than 62% of the C‐PC contained in the biomass in the form of pure C‐PC concentrates. Copyright © 2010 Society of Chemical Industry