I have check the solution and have repeated a few times. My colleague suggested that the Top 10 may have rejected the plasmid during growth. Therefore the new generation of Top 10 do not contain the plasmid. I have also repeated the plasmid extraction with kit but to no avail. You will directly see your plasmid and find if your Kit work.
Cells grow with no insert.
The culture is clowdy but not saturated and never gets saturated. I always question when an overnight culture is not saturated since I had that experience more than once. It could also be that your current stocks of ampicillin have deteriorated with age. I have also had problems subcloning a gene into Top10 cells. I've had to use other strains, I've had better luck with JM109 and DH5a cells.