沼泽红假单胞菌高产辅酶Q10菌株的诱变选育研究

以沼泽红假单胞菌为出发菌株,通过紫外诱变和罗红霉素抗性筛选,以期获得辅酶Q10高产菌株.试验结果表明,紫外照射时间60-70s时可能达到最大正向突变概率.通过紫外诱变、罗红霉素初筛和发酵复筛,获得一株沼泽红假单胞菌突变株R-1,辅酶Q10产量达到0.021g/L,较出发菌株产量（0.018g/L）提高16％.经过6次传代培养,突变菌株产辅酶Q10产量稳定,可用于进一步研究.     

耐高浓度甘油的1,3-丙二醇生产菌的诱变选育

利用紫外线对克雷伯杆菌进行诱变,筛选出耐高浓度甘油且1,3-丙二醇(1,3-PD)产量较高的突变株KpⅥ.实验结果表明,在距离34 cm,功率30 W的紫外灯垂直照射下,最佳紫外诱变时间为6 min,此时,致死率为90.9%.克雷伯杆菌经过紫外诱变后,菌落明显增大,是原始菌株的2~4倍;变异菌株KpⅥ经过6代遗传稳定性考察,甘油消耗率和1,3-PD产量稳定,且保持了较高水平.在甘油质量浓度为90 g.L-1的条件下,变异菌株KpⅥ的甘油消耗率为98.3%,甘油转化率为50.4%,1,3-PD产量为44.81 g.L-1,生产能力达到0.75 g.(L.h)-1.     

丁二酸高产菌株的选育及发酵条件优化

对产琥珀酸放线杆菌RH进行紫外诱变选育,用TLC法初筛得到84株丁二酸产量较高的菌株;对初筛得到的菌株进一步用HPLC法复筛,得到1株高产突变菌株C4-1.经遗传稳定性分析,发现该高产突变株连续传5代后丁二酸产量基本保持稳定.碳源、氮源优化实验表明,突变株C4-1产丁二酸的最适碳源为液化淀粉,最适氮源为玉米浆干粉,且可以采用液化玉米粉添加少量玉米浆干粉代替液化淀粉和玉米浆干粉,以节约成本;在优化条件下突变株C4-1三角瓶发酵60h,丁二酸产量达到(52.91±0.53)g/L,较原始菌株提高了33.46%.     

高产2-苯乙醇酿酒酵母的选育

从8株酿酒酵母中初筛到一株2-苯乙醇产量达1.48g.L-1的菌株FD0419.以此为出发菌株,分别进行硫酸二乙酯化学诱变和原生质体紫外诱变,获得3株耐受性提高但2-苯乙醇产量下降的菌株,再与出发菌株进行原生质体融合.最终,筛得菌株R-UV3,其2-苯乙醇产量达2.51g.L-1,比出发菌株提高69.6%.     

微波辐照选育L-乳酸高产菌的生物学特性研究

在低功率微波条件下,采用水循环冷却器,对干酪乳杆菌鼠李糖亚种(Lactobacillus casei subsp. rhamnosus)X1-12进行诱变处理,在微波功率400 W,辐照时间3 min的诱变条件下得到L-乳酸产量为115.8 g/L的突变株W3-9,比原始菌株X1-12提高了57.98%,连续遗传8代,产酸性状稳定.通过原始菌株和突变株的生理生化实验,可知微波辐照后的菌株生物学特性发生部分改变.     

抗蛋氨酸结构类似物突变株的筛选

以北京棒杆菌AS1.299经诱变后获得的高产蛋氨酸突变株N3-10作为出发菌株, 依次采用蛋氨酸结构类似物亮氨酸、 原亮氨酸和乙硫氨酸平板对
诱变后的突变株进行筛选, 得到蛋氨酸高产菌株依次为L3,LN7和E31. 结果表明, 亮氨酸对突变株N3-10的抑制质量浓度为8 g/L, 原亮氨酸对突变株L3的抑制质量浓度为3 g/L, 乙硫氨酸对LN7突变株的抑制质量浓度为3 g/L, 经紫外诱变和3种蛋氨酸结构类似物的筛选, 最终获得蛋氨酸产量最高突变株E31, 产量为1.479 g/L, 比出发菌株N3 10蛋氨酸产量高0.379 g/L. 经5次传代, 产量稳定.     

γ-聚谷氨酸高产菌株的选育和发酵培养基的初步优化

以实验室保藏的一株枯草芽孢杆菌为出发菌株,采用紫外、亚硝基胍以及60Coγ射线对其进行复合诱变,获得一株γ-聚谷氨酸高产突变株,在基础培养基中产量是出发菌株的3.11倍,并且突变株经过传代10次,发酵能力稳定;通过正交试验对突变株的发酵培养基进行了初步优化,突变株在一组培养基上的γ-聚谷氨酸产量可达到33.81g/L,是优化前的1.11倍。该突变株的摇瓶发酵产量较高,值得深入开发研究。     

产木聚糖酶海洋微生物的筛选与诱变育种

以自制木聚糖为初筛培养基的唯一碳源,从多个海洋来源样品中一共筛到60株有透明圈且形态各异的菌株,摇瓶发酵结果显示,38株具有产木聚糖酶能力,其中B659菌株产酶能力最高,酶活力为525.3 U·m L-1.结合B659菌株的形态特征和16S r DNA序列分析鉴定该菌株属于Bacillus属.对B659菌株进行紫外诱变,筛选得到酶活提高13.9%且稳定遗传的突变菌株G3-17;对G3-17菌株进一步进行微波诱变得到酶活较G3-17菌株高出11.6%且稳定遗传的突变菌株W1-40.对B659菌株和W1-40突变菌株进行发酵试验,72 h时W1-40菌株的酶活力达到645.2 U·m L-1,比B659菌株(517.9 U·m L-1)提高24.6%.     

紫外和He-Ne激光复合诱变筛选L-丙氨酸高产菌株

对L-丙氨酸产生菌德阿昆哈假单孢菌分别进行紫外、激光以及紫外—激光的复合诱变筛选,结果表明,复合诱变正突变率幅度较大.从紫外—激光的复合诱变得到的突变株中筛选到3株遗传性状稳定的高产菌株,其L-天冬氨酸-β-脱羧酶的活性较之出发菌株分别提高19.97%、30.04%和26.55%,经9次传代培养,突变株性质稳定.     

发酵木糖高产乙醇树干毕赤酵母菌株的Co60诱变选育

【目的】选育能够利用木糖高产乙醇的酵母菌株。【方法】采用Co60诱变树干毕赤酵母(Pichia stipitis),筛选乙醇产量高的突变菌株,并对原始菌株、突变菌株的生长发酵特性和两个菌株对高浓度木糖、乙醇的耐受性进行比较。【结果】在YPX培养基上筛选获得1株能够高效发酵木糖的突变菌株1K-9。该菌株在50mL 15%FM发酵84h,发酵液乙醇含量最高达(51.034±0.112)g/L,比原始菌株提高10.05%;在500mL 15%FM发酵96h,乙醇含量最高达(51.390±0.119)g/L;在500mL 20%FM发酵156h,乙醇含量最高达(52.496±0.513)g/L。菌株1K-9在HSM培养基或含4%~5%乙醇的YPX培养基中生长良好,在含6%~7%乙醇的YPX培养基中生长缓慢。【结论】Co60诱变对于树干毕赤酵母(Pichia stipitis)菌株是有效的,能选育出木糖高产乙醇酵母菌株1K-9。     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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.     

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-     

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-     

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     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

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

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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