Longevity of plain LB agar plates - (Sep/02/2009 )
How long to plain (no antibiotic) LB plates last?
My plan is to make use of other people's old (>1 month) and unwanted ampicilin plates but just spreading fresh antibiotic on top.
If they have been in the refrigerator, you probably need not do anything -- they will be fine as is. LB plates which are not dried out and have no growth are good nearly indefinitely, in my experience. The antibiotic may degrade over time, and X-Gal definitely does. Tet plates are light sensitive.
I agree with phage434.
But about the antibiotic: we never use them if its older then 4weeks.
Thus you will need to put some new antibiotic on the plates.
I agree with phage434.
But about the antibiotic: we never use them if its older then 4weeks.
Thus you will need to put some new antibiotic on the plates.
(I have never done that before, not sure if thats ok to do. If I would do that: I would pore the antibiotic on it, spread it and then let it dry.... and also: its not easy to get the propper concentration of antibiotic then...)
That is real sloppy science. You have no idea the quality of the media (other peoples old plate they don't want) and wil certainly end up with sme high but undetermined level of ampicillin.
Start over.
Why would u even wanna do that in the first place? u guys run out of LB or something?
I personally don't really like to use other ppl's stuff whenever possible.
hanming86 on Sep 4 2009, 04:12 PM said:
I personally don't really like to use other ppl's stuff whenever possible.
In general I agree with what you and GeorgeWolff, but if we are talking about plain agar plates, there is nothing wrong with using "older" plates.
If the plates are there and no one uses them... then why let them go to waste.
If you need plates with an antibiotic in it, then we speak of different things.
Replying pito,
because, you will never know what's actually inside the LB plate unless u make it yourself.
It could have been labelled LB but actually contained something else that only the one making em knows.
So to be on the safe side , i still prefer whenever possible to make my own stuff.
there's nothing wrong with using you OWN old plates however. i can live with that.
hanming86 on Sep 6 2009, 04:38 AM said:
because, you will never know what's actually inside the LB plate unless u make it yourself.
It could have been labelled LB but actually contained something else that only the one making em knows.
So to be on the safe side , i still prefer whenever possible to make my own stuff.
there's nothing wrong with using you OWN old plates however. i can live with that.
Yeah, that is true.
You are indeed correct, however I am assuming that he asks what kind of plates it are...
I just depends on the circumstances..
But indeed, you are right, as GeorgeWolff is too.
I vote with you and georgie, pito. What surprises me is the "sloppy science" (per georgie) the question suggests. Most folks are pretty jealous of their scientific rigor and this one found some old antibiotic plates in the frig and wants to toss on some more antibiotic and use 'em.