S-Gal® (sodium salt) is an autoclavable, water-soluble, chromogenic substrate for β-galactosidase, used to determine the presence or absence of a cloned DNA insert in bacteria growing on agar plates. S-gal® is designed to replace X-Gal in blue-white selection of recombinant bacterial colonies with the lac+ phenotype.
Application
S-Gal®/LB Agar Blend has been used for the identification of recombinant bacterial colonies.[1][2][3]
Suitable for use in selection of recombinant bacterial colonies with the lac+ phenotype. S-Gal® (sodium salt) is water-soluble, autoclavable and can be added to bacterial broth containing agar prior to autoclaving.
When S-Gal® is cleaved by β-galactosidase, the resulting product will chelate ferric ion to create a black, insoluble precipitate. Lac+ colonies grown in the presence of S-Gal® and ferric ion turn an intense black color, allowing for easy differentiation between lac+ and lac- colonies.
Preparation Note
Suspend contents of one packet in 500 ml distilled or deionized water. Sterilize by autoclaving for 15 to 20 minutes at 121-124°C. For microwaving, heat suspended mix until initial boiling. Mix well. Heat for short intervals with mixing until agar component is in solution. Do not allow boiling for extended periods of time. Antibiotics should be added following autoclaving or microwaving, after cooling to 48-52°C.
Other Notes
The ferric or Fe3+ ion is required for color development and must be added to any S-Gal® formulation. A medium prepared with S-Gal® is moderately dark due to the presence of ferric ammonium citrate. This darker background often provides enhanced contrast for automated colony counting or isolation.
Legal Information
S-GAL is a registered trademark of Merck KGaA, Darmstadt, Germany
Journal of bacteriology, 188(7), 2427-2434 (2006-03-21)
In eukaryotes, N-linked protein glycosylation is a universal modification involving addition of preformed oligosaccharides to select Asn-Xaa-Ser/Thr motifs and influencing multiple biological events. We recently demonstrated that Campylobacter jejuni is the first member of the Bacteria to possess an N-linked
The identification of single-chain antibodies (scFvs) that interfere in vivo with the building of the complex that activate the prokaryotic, sigma54-dependent promoter Pu of the catabolic TOL plasmid pWW0 is reported. To this end, a phage M13 library of scFvs
LifeScience Quarterly: A superior dye to X-gal for clonal selection.
Heuermann, K. and Cosgrove, J.
Sigma data, 2(2), 2-4 (2001)
Heat shock protein 70 (Hsp70) subtype expression in neuroendocrine tissue and identification of a neuroendocrine tumour-specific Hsp70 truncation.
Zierhut B, et al.
Endocrine-related cancer, 11(2), 377-389 (2004)
Differential expression of alphaB-crystallin and Hsp27-1 in anaplastic thyroid carcinomas because of tumor-specific alphaB-crystallin gene (CRYAB) silencing
Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.