Search results
Results from the WOW.Com Content Network
The blue–white screen is a screening technique that allows for the rapid and convenient detection of recombinant bacteria in vector-based molecular cloning experiments. This method of screening is usually performed using a suitable bacterial strain , but other organisms such as yeast may also be used.
This allows for blue–white screening when using host strains such as E. coli JM109, which produces only the C-terminal portion of lacZ, also known as the β-polypeptide. [3] If pUC19 is inserted into E. coli JM109 and grown on agar media supplemented with IPTG and X-gal , then colonies will appear blue, as the plasmid encodes for the α ...
This design enables efficient identification of recombinant plasmids, as the insertion of foreign DNA into the MCS disrupts the marker gene, allowing for blue-white screening or other selection methods. [6] In expression vectors, MCSs are positioned between a promoter and a terminator to regulate gene expression. The upstream promoter can be ...
DH5-Alpha Cells are E. coli cells engineered by American biologist Douglas Hanahan to maximize transformation efficiency. They are defined by three [1] mutations: recA1, endA1 which help plasmid insertion and lacZΔM15 which enables blue white screening.
The presence of an active β-galactosidase may be detected when cells are grown in plates containing X-gal, the blue-colored product precipitated within cells resulted in the characteristic blue colonies. However, the multiple cloning site, where a gene of interest may be ligated into the plasmid vector, is located within the lacZα gene.
An alternative to a selectable marker is a screenable marker, another type of reporter gene which allows the researcher to distinguish between wanted and unwanted cells or colonies, such as between blue and white colonies in blue–white screening. These wanted or unwanted cells are simply non-transformed cells that were unable to take up the ...
Discover the latest breaking news in the U.S. and around the world — politics, weather, entertainment, lifestyle, finance, sports and much more.
Additionally, the cloning vectors may contain colour selection markers, which provide blue/white screening (alpha-factor complementation) on X-gal medium. Nevertheless, these selection steps do not absolutely guarantee that the DNA insert is present in the cells obtained.