排序方式: 共有26条查询结果,搜索用时 171 毫秒
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离子注入改良维生素C二步发酵混合菌研究:(II)2—酮基—L—古龙酸高产?… 总被引:1,自引:0,他引:1
考察了不同碳氮源、碳氮比、金属离子和有机溶剂等以及环境因子,如起始pH,通气量和种龄等对高产菌系IPPM-1028发酵水平的影响。实验结果表明,适宜的碳氮比对产酸有明显的影响;在培养基中加入适量的金属离子如Mn^2+、Ce^3+、Ce^4+或La^2+以及增加通气量均有利于2-KLG的产生。二甲苯和乙酸己酯对产酸也有一定的刺激作用。发酵周期一般为60 ̄64h,2-KLG浓度可达76g/l左右,转化 相似文献
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离子注入花生四烯酸产生菌诱变选育 总被引:44,自引:0,他引:44
利用离子束注入生物技术对花生四烯酸产生菌(Mortierella alpina)进行诱变高产菌筛选。筛选到高产菌I49N18,该菌每升培养液可得生物量30.80g(约4%的含水量),干菌体油脂含量为25.8%,其中花生四烯酸的含量占总.脂的45.37%。30L和250L发酵罐发酵试验,该高产菌的花生.四烯酸得率为4.0g/L。 相似文献
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离子注入对微生物细胞的刻蚀与对DNA的损伤及修复 总被引:10,自引:0,他引:10
宋道军 姚建铭 吴丽芳 王纪 涂友斌 余增亮SONG Dao-jun YAO Jian-ming WU Li-fang WANG Ji TU You-bin YU Zeng-liang 《遗传》1999,21(4):37-40
以耐辐射异常球菌为试材,以E. coli 为对照,用显微扫描电镜和3H-TdR标记,研究了离子注入对微生物细胞的刻蚀与对DNA的损伤及其修复。结果表明,注入离子对细胞存在着刻蚀损伤;中性蔗糖梯度密度离心沉降分析证明, 大剂量下离子注入可直接导致DNA损伤,并观察到在对应的存活率峰值注入剂量下,D. radiodurans修复损伤DNA的能力比E. coli 强,还证明了细胞经不同时间温育后,损伤的DNA分子得到了部分修复。
Abstract: The direct action of N+implantationin on D. radioduransand E. coliwas investigated by SEM, and their cells were labeled with 3H-TdR, which were implanted by 20keV N+after incubation 18hours, then the DNA of lysed cells was subjected to the neutral sucrose gradient(5%~20%) ultra-centrifugation sedimentation analysis. The results showed that N+implantation exerted direct action on two kinds of microorganisms; the momentum transfer and energy deposition of implantation ions produced the direct etching damage on cells, and repair DNA efficiency of D.radiodurans was higher than that of E. coli. Meanwhile, the damaged DNA incomplete repairing was observed. When incubation was continued up to 6 hours, the rejoined DNA molecules broke again. The repair of damaged DNA could be inhibited by 200μg/ml chloramphenicol. This suggested that DNA damage was serious by ion implantation and damaged DNA repair of cells need continuously synthesizing repair enzyme. 相似文献
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