共查询到20条相似文献，搜索用时 78 毫秒
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李俊刚 《绵阳师范学院学报》1994,(Z1)
本研究对生淀粉糖化菌黑曲霉S一1原生质体制备与再生因素进行了探讨.该菌菌丝体酶解2小时以后,可制得2×10~8/ml原生质体,其再生率达13.3%.采用波长λ_1=260nm、λ_2=266nm,能量8mj的激光直接照射该菌原生质体.结果表明:激光对原生质体的致死率比对孢子的致死率高;激光对原生质体的诱变效应也较好,其正变率比孢子的正突变率高34%;与出发菌株相比生淀粉糖化酶活性平均提高37.4%,最高突变株酶活提高91%. 相似文献
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木耳原生质体的释放和再生研究 总被引：2，自引：1，他引：1
探讨了裂解酶组合、菌丝体培养基、菌丝体培养时间和酶作用时间对木耳原生质体释放的影响及菌丝体培养时间、再生培养基和渗透压稳定剂对木耳原生质体再生的影响;提出了木耳原生质体释放和再生的有效方法。 相似文献
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紫外线、氯化锂对柴油杉醇产生菌HQD33原生质的诱变 总被引：1，自引：0，他引：1
本文采用3%溶壁酶和2%蜗牛酶的混合酶液,30℃酶解紫杉醇产生菌树状多节孢HQD33五小时，原生质体产量可达3.35×106个/ml；通过双层平板培养法再生，再生率为4.67%～21%左右。用紫外线单独作用和紫外线、氯化锂复合处理30秒，原生质体的致死率分别为60% 和74.18%，从而，弄清了氯化锂和紫外线对树状多节孢原生质体的诱变条件，为诱变育种选择合适的诱变剂量提供了参考。 相似文献
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本实验以经过青霉素筛选后的两株絮凝菌为对象,分别测定其溶菌酶处理前总菌数、溶菌酶处理后总菌数和原生质体再生菌数,计算原生质体形成率和再生率,并对PEG的作用浓度和时间进行优化。实验结果：F2原生质体形成率为99.97%,F6原生质体形成率为99.96%,F2原生质体再生率为0.4225%,F6原生质体再生率为0.5423%,初步判断溶菌酶处理后得到的原生质体在质量和数量上满足细胞融合需求,确定了原生质体融合PEG最佳作用浓度为30%,最佳作用时间为10 min,以保证原生质体融合的完成。 相似文献
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万南安 《岳阳职业技术学院学报》2006,21(5):69-70
通过对秀珍菇原生质体的分离与再生的影响因素的试验研究,表明以0.6M甘露醇为渗稳剂用1%纤维素酶 1%蜗牛酶,30℃酶解3～4小时原生质体产生最高,原生质体再生则以0.6M甘露醇或0.6M蔗糖为渗稳剂较好。 相似文献
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酶辅助法提取大青叶中总黄酮及抗氧化性研究 总被引：1，自引：0，他引：1
本论文采用酶辅助法提取大青叶中的总黄酮,先用纤维素酶酶解,再用乙醇回流提取大青叶中总黄酮。分别固定乙醇提取液的浓度为70%,料液比为1∶20g∕mL,回流时间为2h。初步探究了纤维素酶浓度、酶解pH、酶解温度、酶解时间四个单因素对大青叶中黄酮提取率的影响。设计正交实验确定酶辅助法提取大青叶中总黄酮的较佳条件为:纤维素酶浓度为4U/mL、酶解pH=4.5、酶解温度为40℃、酶解时间1.5h,总黄酮提取率高达2.85%。另外还研究了大青叶总黄酮提取液对羟自由基的清除活性,与BHT的抗氧化剂活性作对照实验,结果表明大青叶中的总黄酮对羟自由基有较强的清除活性。 相似文献
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以稀硫酸预处理的麦秆为底物,通过单因素试验和正交试验优化了底物的酶解条件.结果表明：酶解条件的主次顺序为底物质量浓度、酶质量浓度、酶解时间、酶解温度和pH;最佳酶解条件为底物质量浓度0.25 g/L、酶质量浓度2 g/L、酶解时间36 h、酶解温度45℃和pH为5.0,此时总还原糖含量最大为707.07 mg/g,糖含量显著增加.酶解对于提高麦秆的糖化率是非常有必要的. 相似文献
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选用木瓜蛋白酶对低值巴浪鱼蛋白进行水解,分析各因素对鱼蛋白水解的影响,以水解度为特征性指标,通过L9(34)正交试验确定水解的最佳条件.实验结果表明:酶浓度为1 600 U/g,底物浓度3.5%,酶解时间5h,酶解温度60℃.在此条件下鱼蛋白的水解度为54.51%. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献