小中大
谢谢你的耐心解答
我还想把这个问题讨论的深入一点:
我做原核表达用的是invitrogen的pRSET载体,说明书上有这么一些话:
Before proceeding with the expression streak out the BL21(DE3)pLysS transformant containing the recombinant plasmid on LB containing 35ug/ml chloramphenicol and 50ug/ml ampicillin.Chloramphenicol selects for maintenance of the pLysS plasmid required for T7 lysozyme expression and ampicillin selects for the pLysS plasmid.It is important to maintain BL21(DE3)pLysS strains on LB and chloramphenicol as loss of the plasmid will increase basal levels of transcription.
另外,在后面的pilot expression的说明中,关于第一天摇菌后第二天扩大诱导的时候
有这么一句话,特地用括号圈出来的:
the next day.inoculate 25ml of SOB(It is not neccessary to include antibiotics for expression)to an OD600 of 0.1 with the overnight culture.
我对这些地方还感到有些疑惑,不明白streak out的意思。另外我也从来没用过氯霉素摇菌,而且我用的菌也不是这种pLysS的,而只是一般的BL21,不知道氯霉素是针对这种菌的还是……,总之我不太理解,关于质粒丢失这个问题,还希望把这个问题提出来大家讨论讨论。