cloning and trasnformation of bacteria containnig ampicilin resistant gene
Were the colonies on the plates healthy and large? Sometimes you can get small background colonies on an LB-Amp plate, especially if it is a week or two old, and these are not really resistant and won't grow in liquid.
But if in fact the colonies are good and healthy colonies, I would do a control with your broth to be sure there was not some error, but make sure other clones do grow.
Occasionally you can get a clone that fails to grow, or grows very poorly in liquid, but this is pretty infrequent and I would not expect all your clones to be this way.
If you left your bacteria in the fridge for over a month, they could be dead, although uncommon, it has happened to me in short periods of even three weeks. Dead bacteria look the same as live bacteria and because on the spot in the agar where they first grew there is no amp left (as they degraded it), they are still visible. I knew that happened to me because when I checked them with colony PCR my insert was there, along with the vector of course, and still, after putting them in YT broth they wouldn't grow, and there was nothing wrong with the broth nor the antibiotics as I controlled for that..
dear B R Siddharth
I suggest you first search to see if your protein has been expressed in your host bacteria by another researcher or not, (you can even search for homologous proteins). If this protein has already been expressed by another researcher, it is very likely that you have selected colonies for expression that were not transformed by your target plasmid, in which case I suggest that you read the comment I wrote in the post at the end of this comment.
Also, after reading the comment, I suggest that you also pay attention to the contents that I mention below.
read this post and my comment too
https://www.researchgate.net/post/Does_bacterial_transformation_can_cause_a_change_in_their_appearance_on_LB_Agar/1
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