• 作者： 田蔚城
• 作者服務機構： 行政院國家科學委員會生物及醫農學組 國立陽明醫學院微生物學科
• 中文摘要： 以不同的實驗狀況，來研究青黴菌對N-Methyl-N'-Nitro-N-Nitrosoguanidine(NTG)突變誘發劑的各種反應，以期 達到選出青黴素高?量菌株的目的。我們認?選種的最佳狀況?：NTG的最適濃度是5X10-4M ,抱子經過16到24分鐘的 處理，其活存率?11%到22%。 由於菌株的不同，我們無法以Macdonald's氏方法分離出突變菌株來。我們將該分離法重新設計，將發芽的孢子經 Ethylmethane Sulfonate (EMS)處理後，再以低濃度的Nystatin抗生素處理，需要特別生長因子的突變株相對的增加， 其分離率增高?17.7%。
• 英文摘要： To isolate high penicillin yielding mutants, the efficacy of NTG in Penicillium chrysogenum under various conditions was studied. Conidia were treated with various concentrations of N-Methyl-N'-Nitro-N-Nitrosoguanidine (NTG) for 30 minutes and complete inactivation of spores was observed at 1 x 10-3 M. A maximum of 4% auxotrophs were obtained at 5 x 10-5 M. Using 5 x 10-4 M NTG as a given concentration, conidia were treated over different time intervals, the lethality increased to 99% in 40 minutes. The frequency of auxotrophs increased linearly with time intervals. The optimum condition for the isolation of high penicillin yielding mutants is at a concentration of 5 x 10-4 M NTG with a 16 to 24 minute interval resulting in 11% to 22% survivors. For isolation of auxotrophs, germinating conidia were treated with Ethylmethane sulfonate (EMS) followed by propagation on cracked corn. The resulting conidia were plated on minimal medium containing 1-2 μ/ml nystatin. After 4-5 days incubation, the microcolonies were overlaid with complete medium and incubated for 1-2 weeks. Using the total isolation procedure, 102 auxotrophs (17.7%) were isolated from 574 colonies: 70 adenine auxotrophs, 27 amino acid auxotrophs, 4 vitamin auxotrophs, and 1 unclassified.
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