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B3928

Sigma-Aldrich

Blue-White Select Screening Reagent

for selection of recombinant bacterial clones

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NACRES:
NA.85

grade

for molecular biology

Quality Level

form

liquid

usage

sufficient for 125 dishes (90 mm)

technique(s)

nucleic acid detection: suitable

suitability

suitable for nucleic acid staining

shipped in

dry ice

storage temp.

−20°C

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S7313C4478M1942
S-Gal® sodium salt reagent for selection of recombinant bacterial clones

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S-Gal® sodium salt

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C4478

S-Gal®/LB Agar Blend

form

liquid

form

powder

form

powder

form

liquid

technique(s)

nucleic acid detection: suitable

technique(s)

-

technique(s)

microbiological culture: suitable

technique(s)

thin layer chromatography (TLC): suitable

suitability

suitable for nucleic acid staining

suitability

-

suitability

-

suitability

-

shipped in

dry ice

shipped in

-

shipped in

-

shipped in

-

storage temp.

−20°C

storage temp.

room temp

storage temp.

room temp

storage temp.

room temp

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.

Features and Benefits

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

Components

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

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

Storage Class Code

10 - Combustible liquids

WGK

WGK 3

Flash Point(F)

188.6 °F

Flash Point(C)

87 °C

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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Customers Also Viewed

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Characterization by in vitro complementation of a peptide corresponding to an operator-proximal segment of the beta-galactosidase structural gene of Escherichia coli.
A Ullmann et al.
Journal of molecular biology, 24(2), 339-343 (1967-03-14)
Ausubel, F.M., et al.
Current Protocols in Molecular Biology, 1-1 (1995)
D S Biard et al.
Biochimica et biophysica acta, 1130(1), 68-74 (1992-02-28)
We have investigated the use of various Epstein-Barr virus (EBV)-based vectors bearing the two components of the Escherichia coli lac operator-repressor (lacO, lacI) complex. Our aim was to develop a model system of gene expression by looking at the transcription
Methylation of single-stranded DNA in vitro introduces new restriction endonuclease cleavage sites.
B Gronenborn et al.
Nature, 272(5651), 375-377 (1978-03-23)
Regulation of the Escherichia coli lac operon expressed in human cells.
Bioard, D.S. et al.
Biochimica et Biophysica Acta, 113, 68-74 (1992)

Protocols

Blue-White Select™ Screening Reagent

Blue/white color selection is a routine technique employed by molecular biologists. This technique simplifies the differentiation between colonies/plaques that contain a cloning vector without an insert and those that contain a vector harboring an insert of interest.

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

Contact Technical Service