100X Steinberg’s Stock

119g Hepes

34g   NaCl

2.06g magnesium sulfate•(7 H2O)

0.8g  calcium nitrate•(4 H2O)

0.5g  potassium chloride    

bring to 1L using milliq H2O and pH 7.5



Steinberg’s (working solution)

10 L  milliq water

100 ml 100x steinberg’s stock

500 ul pen/strep    pH 7.4



500 ml steinberg’s solution

0.1g ms222 powder       pH 7.4


Xenopus buffer

MBS-H (Modified Barth solution)                         10x/1l

88mM NaCl                                                                51.4g

1mM KCl                                                                   0.75g

2.4mM NaHCO3                                                                                     2.0g

0.82mM MgSO4 x7H2O                                             2.0g

0.33mM Ca(NO3)2 x4H2O                                          0.78g

0.41mM CaCl2 x2H2O                                                0.6g

10mM HEPES                                                            23.8g

10mg/ml Streptomycin Sulfate and Penicillin              1ml 10mg/ml stock (-20, antibiotics)


adjust pH to 7.4 with NaOH

sterile filter buffer


NOTE:  The working dilution of MBS-H is 0.1x.  This means that the 10x stock should be diluted 100x to get the final working concentration.