发信人: Ras (很颓的猪。), 信区: Biology
标 题: Re: why this E.Coli grow so slow?
发信站: The unknown SPACE (Thu Jul 13 20:26:48 2000), 转信

1. never heard of measuring bacterial at OD546 and calculating as u
said below. We only do it at OD600.
2. What temperature you grow the cells? Hope it is 37, not 30.
BL21(DE3)Plyss does grow relatively slower than other E.Coli strains.
However, it is not as slow as yours.
3. In fact, 12 hours for your transformed culture to reach OD 0.8 is not
terribly slow. It usually take us 6-9 hours to do so.
4. Last suggestion, make sure your Amp and Chl concentration is correct.
Even if they are correct, you can still try to lower their concentration
(particularly Chl) to half (17/mg/ml I believe). Sometimes that helps.


【 在 whoknowit (冰毒) 的大作中提到: 】
: I think it was not because of over growth.
: Because: 1. OD(546nm)= 7/6 * OD(600nm)
: 2. it takes 12hr to reach 0.8 of OD at 546nm after transfering
: 1% of overnight growth culture into new culture.
: 3. while the non-transformed cell just take 3 hr to get that OD.
: one error in my original post.
: the two antibiotics are ampicillin and chlorampenicol, not amp and rifamp.
: 【 在 coconut (可可) 的大作中提到: 】
: : Perfectly normal.
: : The bacterial was not in growth phase. It could be caused by
: : 1. high cell density. O.D. can mislead you sometimes because
: : that can vary for different strains. But don't people
: : usually use OD 600 (598) to check cell density?
: : 2. the cells were in cold for a period of time.
: : 3. lack of oxygen.


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