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preparation of LB/ampicillin/IPTG/X-gal plate - (Apr/08/2011 )

i first prepared a LB-ampicillin plate and store the plate in 4'C fridge for three days.

for preparation of LAIX (LB/Ampicillin/IPTG/X-Gal) plates, i follow this protocol:

Take LB / amp plates into laminar flow, spread 100 ul IPTG onto plates and let adsorb by placing inverted in 37 deg C incubator for 30 min. After this, spread 20 ul of X-Gal onto plates, then let adsorb again at 37 deg C.

Now, the problem is, after taking the LB-ampicillin plate out of the fridge, i did not warm it first
so there was a lot of moisture on the surface of the plate
i proceed directly to spreading IPTG --> incubation --> spreading x-gal --> incubation.
after that, when i looked back at the plate, they were all wet.
and it is only at this time that i realize that i forgot to dry the plates after taking them out of the fridge.

so can my plates be used now?
can anyone help?


Yes, just dry them out by putting them at 37C with the top tipped open for an hour or so.


Are you guys not affraid of contamination if you put the plates opened in an incubator?
I know that the changes are small with the antibitiocs on the plate but still, cant you get contamination?

I leave my plates to dry in the laminair flow to avoid contamination and yes, they might be not 100% dry.. but it works for me.


Yes you can get contamination, but the incidents of such an event happening isn't high enough to worry about.. (unless the incubator is completely filled with spores).

You could also leave the plate with its over open beside a bunsen burner flame. The flame will keep things from settling on the plate.

People working with laminar flow hoods tend to be a protective when you suggest bring in a plate of bacteria.