两种蓝藻超低温保存抗冻保护剂的研究

以两种蓝藻为试材,对影响超低温(液氮温度-196℃)保存成活率的保护剂及其配比进行了探讨,发现非渗透保护剂(蔗糖)比渗透性保护剂(DMSO)效果好,混和保护剂与单一蔗糖为保护剂的处理效果未见区别,由两种方法所测成活率看鱼腥藻(Anabaena sp.)比钝顶螺旋藻(Spirulinaplatensis)的抗寒性高.     

不利于生长的pH条件下蓝藻液泡的形成

对鱼腥藻sp.595(Anabaenasp.595)、织线藻246(Plectonema boryanum246)、伪枝藻248(Scytonema hofmanni248)、念珠藻sp.96(Nostocsp.96)、颤藻284(Oscillatoria animlis284)和极大螺旋藻438(Spirulina maxima438)等6种蓝藻进行异常pH条件下的液泡化诱导.在pH5.0,6.5,7.0条件下,鱼腥藻sp.595和织线藻246藻细胞均出现液泡化.其中,鱼腥藻sp.595变化明显,其藻细胞膨大,两端变圆甚至球形化,液泡化程度高,且细胞不均等分裂现象普遍,织线藻246藻细胞稍有膨大,液泡化程度较轻.伪枝藻248表现较弱的敏感性,藻细胞仅在pH6.5时诱导液泡化.念珠藻sp.96、颤藻284和极大螺旋藻438在各种pH条件下均不能发生液泡化,对诱导不敏感.采用压片法检查到鱼腥藻sp.595和织线藻246诱导形成的液泡,在相差显微镜下液泡显示为圆球形,基本透明.结果说明,不利于生长的pH也能诱导蓝藻形成液泡.     

山仔水库两种水华蓝藻磷营养动力学特征

通过分析测定山仔水库两种水华蓝藻:铜绿微囊藻(Microcystis aeruginosa)、浮游鱼腥藻(Anabaena planctonica)在不同质量浓度的无机磷(K2HPO4)和有机磷(ATP)中的生长速率和生物量的变化,并利用Monod方程计算分析两种藻的磷吸收动力学参数(KS和μm),比较了两种水华蓝藻对磷的吸收差异和竞争能力.结果表明,无机磷培养条件下,动力学参数为:μm(铜绿微囊藻)μm(浮游鱼腥藻),KS(铜绿微囊藻)KS(浮游鱼腥藻).有机磷培养条件下,动力学参数较无机磷条件下要小,且两种藻有机磷条件下差异不明显.表明无机磷是水华蓝藻主要吸收的磷源,在无机磷缺乏的条件下,水华蓝藻均能吸收部分有机磷.     

溶藻细菌(B5)的溶藻效果与溶藻特性的初步研究

从富营养化湖泊分离获得的1株菌(B5)，具有明显的溶藻效果。通过凝聚、细胞裂解和生物降解作用能有效去除鱼腥藻细胞。B5菌可能是通过直接接触导致藻细胞的凝集及进一步的生物降解，同时存在一种具有热稳定性且能抑制藻类细胞生长的胞外分泌物。     

植物激素对固氮鱼腥藻(Anabaena azotica ley)的生长效应实验简报

蓝藻固氮的研究在理论上和实践上都有重要意义。本工作的目的在于了解植物激素应用于固氮蓝藻培养中的价值,以便在促进水稻增产工作上有所助益。一、材料和方法实验所用藻种系取自湖北水生生物研究所的一种固氮蓝藻——固氮鱼腥藻(Anabaena azotica Ley)(水生686)。藻类培养液用水生111无氮培养液:硫酸镁(MgSO_4·7H_2O)1.25g,磷酸氢二钾(K_2HPO_4)0.75g,碳酸钙(CaCO_3)1.00g,柠檬酸铁(1%水溶液)5.00ml,柠檬     

广东固氮蓝藻肥效的研究

为促进农业大上快上、粮食丰收,广辟肥源十分重要。“红萍”(即满江红,学名Azolla inlbricata Nakai)之所以有肥效,是因为它的叶腔中有一种共生的蓝藻,即满江红鱼腥藻(Anabaena azolla Lemm.),可以固定空气中游离的氮素,并把它变为使水稻等农作物可以利用的氮化合物。我们自1973年以来,不断探索一些自生的固氮蓝藻在广东省内的培养、应用及肥效。     

铜绿微囊藻、水华鱼腥藻对不同形态磷的摄取及生理响应

研究山仔水库2种水华蓝藻:铜绿微囊藻(Microcystis aeruginosa)、水华鱼腥藻(Anabaena flosaquae)在不同形态磷(4种无机磷和2种有机磷)条件下的生长效应.通过测定胞外总磷含量及碱性磷酸酶活性,比较两者对不同形态磷的摄取能力.结果显示,2种水华蓝藻对正磷酸盐(磷酸氢二钾、磷酸二氢钾)的吸收速度和碱性磷酸酶酶活均大于多聚磷酸盐(焦磷酸钠、聚磷酸钠)和有机磷盐(ATP、甘油磷酸钠);铜绿微囊藻磷吸收速率大于鱼腥藻,但水华鱼腥藻相应的比增长速率和碱性磷酸酶酶活性均大于微囊藻,表明正磷酸盐是水华蓝藻生长所需的最适磷盐;低磷条件下,水华鱼腥藻有可能成为优势藻.     

溶微囊藻菌的分离与溶藻作用

从太湖梅梁湾水域放置的除藻中试反应器的人工介质上分离出1株溶藻细菌,并对该株菌溶解铜绿微囊藻和降解微囊藻毒素的效果与机制进行了研究.结果表明,结合形态学、生理与生化特性以及16S rRNA特异性引物扩增综合分析,初步鉴定该株细菌属于假单胞菌属;对源自太湖的微囊藻的最低溶藻细菌浓度为105个/mL;在太湖水、PBS缓冲液和BG11微囊藻培养基等反应体系中对微囊藻均有较强的溶解作用,24 h藻细胞溶解率分别为85.9%、67.9%和91.0%,完全溶藻时间为48 h.其溶藻方式可能为分泌某种胞外物质所致.该株菌对微囊藻毒素LR(MC-LR)也具有较强的降解作用.在MC-LR起始质量浓度为2.642 μg/L时,细菌对MC-LR作用18,36和72 h的降解率分别为14.2%、51.3%和100.0%.此菌株在太湖水中保持着较好的生物活性,表现出较强的溶藻与降解MC-LR作用.     

山仔水库不同季节围隔放鱼控藻效果研究

2012年不同季节,在山仔水库设置野外原位围隔,采用放养不同鲢、鳙、鲫组合对水体控藻效果进行了研究,设定了鲢的高密度(HS 23.5 g·m-3),鲢鱼、鳙鱼1∶1混养(30.8 g·m-3),鲢鱼、鳙鱼、鲫鱼1∶1∶1混养(30.6 g·m-3)及鲢的低密度(LS11.2 g·m-3)等4种放养方式,探索不同鲢鳙放养组合对不同季节水体的控藻效果.结果表明:山仔水库春季水体以蓝藻门鱼腥藻属(Anabaena)为主要优势种属,约占浮游植物生物量的90%,投加鱼类可以摄食一部分藻体,但对丝状的鱼腥藻滤食性较弱;初夏围隔水体中以蓝藻门束丝藻(Aphanizomenon)为主,仲夏后到秋季,围隔水体转为蓝藻门微囊藻属(Microcystis)为主,水体放养鲢、鳙鱼可以控制一定比例的微囊藻,同时刺激其他藻类的生长;冬季,水体蓝藻门微囊藻属比例逐渐下降到15%以下,硅藻数量逐渐增多,放养鱼类对蓝藻有较好的消化作用,单养鲢鱼或混养鲢、鳙鱼可使蓝藻中微囊藻所占比例降低,但浮游植物种类丰度高于空白组,鲢、鳙鱼促进了浮游植物群落的多样性.鱼类组合控藻效果上,鲢、鳙鲢鲢、鳙、鲫.因此,山仔水库可以考虑选择在冬末初春,混养鲢鳙鱼且控制密度在30~40 g·m-3调控水体的浮游植物群落组成,进而控制蓝藻水华.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has     

Journal of Donghua University ( English Edition) Contents of Volume 31

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