innoculated LB amp plate at 4C - (Jan/06/2010 )
I have inoculated a colony from 6 months old LB Amp Plate (store at 4C) with wild type E.coli cells into 3ml of LB broth. I have incubated it overnight 18hrs, In spite of over night incubation the OD600 was 1.95 and 0.5 in two different 3ml cultures.
So do you think that the 6 month old cells might be the reason for slow growth. For how long the streaked plate will stay good at 4C?
try restreaking the colony onto fresh plates and then grow them in the broth
I think whatever is growing bears only accidental relationship to what was originally on that plate.