【摘要】 目的考察敲入及阻断zwf2基因对6-磷酸葡糖脱氢酶(G6PDH)活性、细胞生长、土霉素合成的影响。方法构建敲入转化子M4018-(zwf2)和阻断转化子M4018-Δzwf2后,以原始菌株为对照,比较敲入转化子菌株M4018-(zwf2)和阻断转化子菌株M4018-Δzwf2摇瓶发酵后G6PDH活性、细胞生长、土霉素合成等生物性质的变化。结果阻断转化子菌株M4018-Δzwf2的G6PDH活性是原始菌的50%左右,敲入转化子菌株M4018-(zwf2)的G6PDH活性则略高于原始菌;阻断转化子菌株M4018-Δzwf2土霉素生物合成水平比原始菌提高27%,比敲入转化子菌株M4018-(zwf2)高约40%;发酵结束时敲入转化子菌株M4018-(zwf2)的细胞干重高于其他2株菌,其它2株菌的细胞干重差异不大。结论zwf2阻断有利于土霉素的生物合成,zwf2增强则对细胞生长有利。更多还原

【Abstract】 Objective To invesgate the effects of zwf2 gene knock-in and disruption on the specific activity of glucose-6-phosphate dehydrogenase(G6PDH),cell growth and oxytetracycline(OTC) biosynthesis in Streptomy-ces rimosus M4018.Methods Taking parent strain S.rimosus M4018 as control,the changes of the specific acitivity of G6PDH,cell growth and OTC level in the media were measured after the mutants M4018-Δzwf 2 and M4018-(zwf2) respectively obtained through gene disruption and knock-in were cultured in shaking flask.Results The specific acitivity of G6PDH in mutant M4018-Δzwf 2 was only half of that in parent strain,while the specific acitivity of G6PDH in mutant M4018-(zwf2) was a bit higher than that in parent strain over the fermentation period.However,the OTC level in mutant M4018-Δzwf 2 was 27 % and 40 % higher than that in parent strain and mutant M4018-(zwf2),respectively.As for the cell growth,the dry cell weight of mutant M4018-(zwf2) was the highest and the difference between mutant M4018-Δzwf 2 and parent strain was not distinct.Conclusion The zwf2 gene disruption benefits the OTC biosynthesis,on the contrary,the reinforced zwf2 gene was better for cell growth.更多还原