A high background is one of the most common quality control issues encountered during the process of western blotting. When a high background occurs, it can be very difficult to distinguish the relevant data from the irrelevant data. A uniform high background can be caused by numerous issues and may take some work to resolve -- but without resolving the situation, the blot may not be readable.
DNA denaturation is the process of breaking down the DNA molecule, generally for the purposes of comparison or sequencing. As with many laboratory techniques, there are a variety of ways to denature DNA -- and each of them tend to be better for specific applications. The top three methods of DNA denaturation are heat, NaOH treatment, and salt. Each of these methods will break the bonds between strands, but may do so with a greater degree of accuracy or lessened disruption.
After the preparation of DNA solutions, some of the enzymes involved may be impacted by the residues of the chemicals that have been used. This may include excess salt, SDS, or other inhibitory substances. In order to properly utilize the results of the DNA preparation, it is sometimes required to perform a drop dialysis. Ideally, the drop dialysis will be able to "wash" the enzymes in question, removing the residue and providing a better and more accurate result.
Poor protein transfer can lead to either a weak signal or a lack of signal being observed during the process of western blotting. Though poor protein transfer does occur fairly often, it's also commonly disregarded as a potential cause for a failure. Consequently, it's an issue that should be considered first when trying to determine the cause of a poor signal.
