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CRISPR/Cas9基因编辑技术已经被广泛应用于工程酿酒酵母的基因插入、基因替换和基因敲除,通过使用选择标记进行基因编辑具有简单高效的特点。前期利用CRISPR/Cas9系统敲除青蒿酸生产菌株酿酒酵母(Saccharomyces cerevisiae) 1211半乳糖代谢负调控基因GAL80,获得菌株S. cerevisiae 1211-2,在不添加半乳糖诱导的情况下,青蒿酸摇瓶发酵产量达到了740 mg/L。但在50 L中试发酵实验中,S. cerevisiae 1211-2很难利用对青蒿酸积累起到决定性作用的碳源-乙醇,青蒿酸的产量仅为亲本菌株S.cerevisiae 1211的20%–25%。我们推测因遗传操作所需的筛选标记URA3突变,影响了其生长及青蒿酸产量。随后我们使用重组质粒pML104-KanMx4-u连同90 bp供体DNA成功恢复了URA3基因,获得了工程菌株S. cerevisiae 1211-3。S. cerevisiae 1211-3能够在葡萄糖和乙醇分批补料的发酵罐中正常生长,其青蒿酸产量超过20g/L,与亲本菌株产量相当。研究不但获得了不加半乳糖诱导的青... 相似文献
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Abstract Assessing resource-use by different life stages of insects is crucial to our understanding of their ecology. Development of appropriate methods by which different physiological states can be identified is therefore significant. We develop one such method for the dacine fly Bactrocera cacuminata (Hering) (Diptera: Tephritidae). In male flies, the ejaculatory apodeme, a structural part of the reproductive endoskeleton, grows as a function of age of the fly. This growth pattern is sigmoid, reaching a maximum threshold that corresponds with the attainment of sexual maturity, as measured by the incidence of first mating. Similarly, in female flies ovarian development appears to be a reliable indicator of sexual maturity. Assuming that similar growth thresholds occur in wild flies, it is possible to use apodeme and ovarian development as measures of physiological/reproductive status in this species. 相似文献
134.
The hydration energetics of natural DNA with various AT/GC-composition and model double-helix polyribonucleotides was studied using a new approach which is based on calorimetric measurements of the dehydration energy of nucleic acid-water systems at various levels of relative humidity. A linear correlation between the dehydration energy and the nucleotide composition of natural DNA was found. 相似文献
135.
The energetics of hydration of natural DNA of different AT/GC content and model double-helical polyribonucleotides was studied. The results obtained by a new approach, which is based on calorimetric measurements of hydration-dehydration energy of nucleic acid-water systems at different relative humidities are presented. A correlation between the dehydration energy and the nucleotide composition of native DNA was found. The energetic characteristics of systems containing deoxynucleoside monophosphates and water clusters of different dimensions were obtained by the Monte Carlo method. The results of computer simulation correlate with the experimental calorimetric data. 相似文献
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雌性黄瓜植株经硝酸银处理后其茎尖和真叶过氧化物酶活性极显著地增加,茎尖24小时、真叶36小时酶活性达到最大值,分别增加了178.2%和284.6%,随后酶活性逐渐下降,但酶活性仍然较对照植株高。多酚氧化酶和超氧化物歧化酶的同工酶活性也增加。同时硝酸银能诱发黄瓜植株过氧化物酶、多酚氧化酶和超氧化物歧化酶产生新的同工酶, 用等电聚焦更能有效地观察新产生的同工酶。 相似文献
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Identification of 40k γ-secalin genes 总被引:1,自引:0,他引:1
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