Changes

β-D-galactopyranoside, C19H21O9Na, MW 416.35,  MDL Number MFCD03458481.

β-D-galactopyranoside, C19H21O9Na, MW 416.35,  MDL Number MFCD03458481.

S-Gal®, sodium salt is a patented water-soluble, autoclavable chromogenic substrate for β-galactosidase that is designed to replace X-Gal in blue-white selection of recombinant bacterial colonies with the lac+ phenotype. Caution: For black color development to occur, ferric ion must be present. Although we recommend ferric ammonium citrate (500 mg/L of media), other ferric compounds can be used to provide this requirement, depending upon your particular system.  From [http://www.sigmaaldrich.com/catalog/ProductDetail.do?N4=S7313%7CSIGMA&N5=SEARCH_CONCAT_PNO%7CBRAND_KEY&F=SPEC Sigma-Aldrich site].

S-Gal®, sodium salt is a patented water-soluble, autoclavable chromogenic substrate for β-galactosidase that is designed to replace X-Gal in blue-white selection of recombinant bacterial colonies with the lac+ phenotype. Caution: For black color development to occur, ferric ion must be present. Although we recommend ferric ammonium citrate (500 mg/L of media), other ferric compounds can be used to provide this requirement, depending upon your particular system.  From [https://www.sigmaaldrich.com/US/en/product/sigma/s7313 Sigma-Aldrich site].

==S-Gal staining conditions==

==S-Gal staining conditions==

According to [http://www.sigmaaldrich.com/catalog/ProductDetail.do?N4=S7313%7CSIGMA&N5=SEARCH_CONCAT_PNO%7CBRAND_KEY&F=SPEC Sigma-Aldrich site]:  

According to [https://www.sigmaaldrich.com/US/en/product/sigma/s7313 Sigma-Aldrich site]:  

Stock solutions of S-Gal can be made by dissolving at 50 mg/mL in deionized water, sterile-filtering and storing at -20 °C.

Stock solutions of S-Gal can be made by dissolving at 50 mg/mL in deionized water, sterile-filtering and storing at -20 °C.

http://www.bio.davidson.edu/courses/genomics/method/xgal.gif

https://bio.davidson.edu/courses/genomics/method/xgal.gif

Cleavage by beta-galactosidase yields a dihalogen-substituted indoxyl, 5-bromo-4-chloro-3-indoxyl:

Cleavage by beta-galactosidase yields a dihalogen-substituted indoxyl, 5-bromo-4-chloro-3-indoxyl:

Oxidation in the presence of an electron acceptor yields a relatively insoluble indigoid dye:

Oxidation in the presence of an electron acceptor yields a relatively insoluble indigoid dye:

=Oxidants used in histochemistry=

=Oxidants used in histochemistry=

Performic acid PMID: 1099403

Performic acid PMID: 1099403

Cepko, C., Ryder, E., Fekete, D.M., and Bruhn, S. Detection of B-galactosidase and alkaline phosphatease activities in tissue. Online: http://genepath.med.harvard.edu/~cepko/protocol/xgalplap-stain.htm. An excellent brief discussion of X-Gal histochemistry. Much of the material presented here was derived using their references.  

Cepko, C., Ryder, E., Fekete, D.M., and Bruhn, S. Detection of B-galactosidase and alkaline phosphatease activities in tissue. Online (archive): https://web.archive.org/web/20160821210733/http://genepath.med.harvard.edu/~cepko/protocol/xgalplap-stain.htm. An excellent brief discussion of X-Gal histochemistry. Much of the material presented here was derived using their references.

=Studies in Enzyme Cytochemistry=

=Studies in Enzyme Cytochemistry=

Recommends ferrocyanide, and notes that it inhibits red blood cell staining "presumably because of the chemical similarity to cyanide"

Recommends ferrocyanide, and notes that it inhibits red blood cell staining "presumably because of the chemical similarity to cyanide"