2-脱氧葡萄糖对酵母虾青素积累及酶法提取的影响

2-脱氧葡萄糖是一种酵母细胞壁合成抑制剂,红发夫酵母培养中添加0．0005％—0．002％（w／v）的2-脱氧葡萄糖可使生物量基本保持不变,但能促进虾青素积累,在增加虾青素产量的同时缩短酶法提取的时间。当添加浓度为0．002％时,虾青素含量可提高到对照组的113．7％,若采用胞壁溶解酶对红发夫酵母破壁提取虾青素,作用12h提取率可达94．7％。同时,2-脱氧葡萄糖应在红发夫酵母培养的前36h添加。     

溶氧及植物激素对红发夫酵母生长与虾青素合成的影响

研究了在含挡板的凹槽(高溶氧)摇瓶培养中添加不同植物激素对红发夫酵母(Phaffia rhodozyma)生长及虾青素合成的影响.结果表明:凹槽摇瓶培养能明显提高细胞生物量和虾青素产量,凹槽摇瓶培养下添加植物激素的最佳条件为0h时添加0.25mg/L 6-苄基腺嘌呤;在最适条件下,虾青素的最大产量和产率分别为58.02mg/L和3.512mg/g,较对照组分别提高了24.56%和10.65%.这说明在细胞生长过程中添加适量植物激素6-苄基腺嘌呤有利于虾青素合成,为红发夫酵母生产虾青素的高密度规模化生产奠定了基础.     

米根霉、法夫酵母双菌共发酵淀粉生产虾青素的初步研究

对米根霉、法夫酵母共发酵淀粉生产虾青素进行了研究．摇瓶试验结果表明，米根霉、法夫酵母共发酵淀粉生产虾青素适宜的培养基为淀粉50g／L、1gKH2PO4/L、1g CaCl2／L、1g酵母膏/L、0.5gMgSO4／L、5g（NH4）2SO4/L，控制培养基初始pH为8．0、发酵温度为22℃及同时接种米根霉和法夫酵母有利于虾青素的合成，5L罐试验结果表明虾青素合成滞后于糖的利用，且分成两个增长阶段，虾青素的最大产量达2．48mg／L．这些试验结果不仅证实了共培养米根霉和法夫酵母发酵淀粉生产虾青素的理论可行性，而且为进一步利用淀粉为原料生产虾青素提供了试验参考．     

雨生红球藻和红发夫酵母混合培养体系的氮代谢机理

雨生红球藻和红发夫酵母是自然界申能够大量合成虾青素的两种主要微生物,二者混合培养比单独培养能提高虾青素的产量,氮代谢是影响虾青素合成的关键因素之一．为此,着重研究了雨生红球藻单独培养及混合培养过程中的氮代谢机理．结果表明,在强光照射诱导雨生红球藻合成虾青素的过程中,藻细胞迅速吸收硝酸盐并向胞外分泌NH_4~ ,培养液中的NH_4~ 浓度上升,同时值pH值也急剧升高．由于NH_4~ 对藻细胞有毒害作用,抑制了虾青素的进一步合成．而在混合培养过程中,即使在虾青素大量合成阶段,培养液中的NH_4~ 浓度也基本稳定．进一步的分析结果表明,红发夫酵母细胞吸收利用了雨生红球藻细胞代谢过程中产生的NH_4~ ,培养液的pH值基本稳定7．0左右,从而使藻细胞内流向虾青素合成方向的碳代谢流始终保持较高的通量,提高了虾青素产量．     

红发夫酵母生产虾青素的氮源补加策略

随着人类对天然虾青素需求的不断扩大,红发夫酵母(Xanthophyllomyces dendrorhous)以其易于培养的优点被选为当前虾青素生产极具潜力的微生物.实验主要从氮源调控入手,阐明虾青素生产机制,以期获得更高的虾青素产量.在微生物生长过程中,氮源的调控对细胞的生长和产物的积累至关重要.考察了在红发夫酵母生长过程中添加氮源对细胞生长及虾青素合成的影响.实验结果表明:补加不同种类的氮源及浓度对菌体生物量以及虾青素的产量有着不同的影响,在合适的时间点补加适量的氮源能明显促进虾青素的积累.根据实验结果,研究确定了最适的补氮时间为24h,最适的补加氮源为谷氨酸,最适的补加质量浓度为0.368g/L,在此补加条件下,虾青素的最大产量和产率分别为3.445mg/L和1.144mg/g,较对照组分别提高了36%和41%,这说明在细胞生长过程中补氮有利于虾青素的积累.     

不同碳源及其浓度对红发夫酵母培养的影响

研究了不同碳源及浓度对红发夫酵母Phaffia rhodozyma生长及虾青春积累的影响。 结果表明碳源浓度在20－30g/L范围内对红发夫酵母生长及虾青素合成有利。在所研究的领域中，糖蜜有利于生长，而木糖有利于虾青春积累。采用木糖和糖蜜的混合碳源，虾青春产量达到1．9mg/L。     

生物素对红发夫酵母生长和虾青素积累的影响

在摇瓶中研究生物素对红发夫酵母生长和虾青素积累的影响.结果表明生物素的添加能促进细胞生长,但对细胞内虾青素含量的提高不利.添加10μg/L生物素时,最大比生长速率达到0.110 h-1;添加6μg/L生物素时,达到最大细胞干重9.95g/L,比没有添加生物素时的7.53g/L提高32%.添加2μg/L生物素时,达到最高虾青素产量和产率,分别为3 825 μg/L和53μg/(L@h),比没有添加生物素时的2 944 μg/L和41μg/(L@h)提高30%.没有添加生物素时,达到最高细胞虾青素含量391μg/g.利用添加2μg/L生物素的方法可以提高虾青素产量,这种方法为提高虾青素产量提供了一种简单廉价的方法.     

乙醇补料对法夫酵母发酵产虾青素的促进效果

将法夫酵母(Phaffia rhodozyma)JMU-MVP14菌株在7 L发酵罐中进行培养,考察在不同葡萄糖质量浓度条件下,补加乙醇对法夫酵母JMU-MVP14菌株的生长和虾青素合成的影响。结果表明:低糖质量浓度下(20 g/L),恒定乙醇浓度发酵明显提高虾青素产量和细胞产率,与分批发酵相比,虾青素产量和细胞产率分别提高了27%和40%,分别达到102.8 mg/L和5.9 mg/g;中糖质量浓度下(30 g/L),恒定乙醇浓度发酵,得到较高的虾青素产量为118.4 mg/L,与分批发酵相比提高了34%;高糖质量浓度下(60 g/L),发酵得到较高虾青素产量为280.6 mg/L,是低糖质量浓度培养下虾青素产量的3.5倍,恒定乙醇发酵与分批发酵相比,生物量和虾青素产量均有显著降低。     

维生素对红法夫酵母产虾青素的影响

采用单因素实验方法研究了不同维生素对红法夫酵母(Phaffia rhodozyma)生长及虾青素积累的影响.结果表明:生物素、泛酸钙、肌醇、VB1可显著提高红法夫酵母的生物量、类胡萝卜素和虾青素的产量,其较适质量浓度分别为0.05,25.00,0.50,0.05 mg/L.VB12和核黄素对红法夫酵母的细胞生长有明显的促进作用,同时可略微提高虾青素产量,其较适质量浓度分别为0.50和0.005 mg/L;VB6、烟酸和叶酸虽然可促进细胞生长,但却明显抑制了虾青素的积累;而硫辛酸既抑制细胞生长也抑制其虾青素的积累.根据单因素实验结果,在培养基中按以上较适浓度添加生物素、泛酸钙、肌醇、VB1、VB12和核黄素,菌体生物量和虾青素质量浓度分别达到5.000 g/L和16.77 mg/L,较对照组分别提高了33.2%和108%.     

摇瓶培养条件对Phaffia rhodozyma生物合成虾青素的影响

研究了在摇瓶间歇培养中影响 Phaffia rhodozyma生长及虾青素合成的多种因素。虾青素的合成与细胞的生长相关。初始葡萄糖浓度对 Phaffia rhodozyma的生长及虾青素的合成有较大影响。虾青素含量在含 3%葡萄糖的培养中生长时有较大值 2 .32 g/L;而细胞干重在初始葡萄糖浓度为 2 %时有较大值 2 .13g/L。低浓度的硫酸铵有利于虾青素的合成及细胞的生长。氧对虾青素的合成有最直接的影响。数值回归分析表明 ,虾青素的含量与发酵培养基溶解氧线性相关 (R2 =0 .987)     

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