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B3928 Sigma

Blue-White Select Screening Reagent

for selection of recombinant bacterial clones

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Properties

Related Categories Core Bioreagents, Gene Reporter Substrates, General Reagents, Life Science Reagents for Cloning, Media Components,
grade   for molecular biology
form   liquid
usage   sufficient for 125 dishes (90 mm)
shipped in   dry ice
storage temp.   −20°C

Description

Components

40 mg/mL IPTG
40 mg/mL X-Gal
(prepared in DMSO)

Features and Benefits

• Intense color contrast for easy colony selection
• Convenient, ready-to-use solution

General description

Sigma’s Blue-White Select Screening Reagent is a chromogenic substrate for β-galactosidase, used to determine the presence or absence of a cloned DNA insert in bacteria growing on agar plates. Blue-White Select Screening Reagent is designed for blue-white selection of recombinant bacterial colonies with the lac+ phenotype.

Principle

When Blue-White Select Screening Reagent is cleaved by β-galactosidase, the resulting product will form a blue precipitate. Lac+ colonies grown in the presence of Blue-White Select Screening Reagent remain white in color, allowing for easy differentiation between lac+ and lac- colonies.

The technique is based on vectors such as the pUC and the M13mp series that carry a fragment of the β-galactosidase gene encoding an a-fragment of β-galactosidase. Exploitation of these vectors requires use of a bacteria strain carrying the complementing gene fragment to allow the assembly of an active complex, resulting in the formation of blue colonies. Disruption of the ß-galactosidase gene by insertion of a DNA fragment into the vector′s multiple cloning site results in the loss of functional β-galactosidase activity; these colonies remain white, allowing for easy differentiation between lac+ and lac- colonies.

Legal Information

Blue-White Select is a trademark of Sigma-Aldrich Co. LLC

Price and Availability

Safety & Documentation

Safety Information

RIDADR 
NONH for all modes of transport
WGK Germany 
3

Documents

Certificate of Analysis

Certificate of Origin

Protocols & Articles

Articles

Introduction to Blue-White Screening

Blue-white screening is a rapid and efficient technique for the identification of recombinant bacteria. It relies on the activity of β-galactosidase, an enzyme occurring in E. coli, which cleaves lac...
Keywords: Antibiotics, Cloning, Culture media, Gene expression, Immunocytochemistry, Peptide synthesis, Polymerase chain reaction, Recombination, Sterilizations, transformation

Protocols

Blue-White Select™ Screening Reagent

Product Description Components Equipment and Reagents Required but Not Provided Precautions and Disclaimer Storage/Stability Procedure Materials References
Keywords: Absorption, Cloning, Degradations, transformation

Peer-Reviewed Papers
15

References

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