LB agar question - (Dec/03/2006 )

I was preparing LB + Kan media plates and these plates require 1.5% Bacto-agar in our lab. However, I mistakenly had an old protocol in front of me and without realizing it, had put in more than twice that amount into my LB media when I was preparing it. I didn't realize this under after everything was done. So, now every plate has every nutrient & antibiotic in correct measurement & brought up to the correct pH, however the Bacto-agar sitting in the plates is 3.75% when they should be 1.5%!

Will these plates still function in Kan selectivity and will colonies still grow on them correctly, like plant plasmid DNA?
What happens when you add in too much (double the amount) of Bacto-agar into LB plates in general? Should I just throw these plates away? Any help is useful.

They will probably work, but the plates will be a little stiff and hard. Colony morphology may be a little weird. I'd at least try them.

What do you mean by colony morphology being a little weird? Could plasmid DNA still grow on these? I know agar is just to aid as a nutrient, but am not sure how colonies respond to different agar concentrations. Generally, what would be the difference between growing plasmid DNA on a 1% agar plate versus a 3% agar plate?

Likely the colonies will not spread out as much, and will bead up a bit more than on a normal plate. But that's just a guess. It should not affect any of the genomic features of the colonies.

agar concentration i guess will affect the hydration state of the plate, agar could make them more stiff and as a result this may affect the growth of colonies. (their size maybe)..also nutrient consumption will be less..