M9 medium: Difference between revisions

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We used to prepare the '''plain M9 medium''' as follows:
==Introduction==
<table>
M9 medium is a minimal growth medium used for bacterial cultures.  It has the advantage of being cheap and has a very low autofluorescence (when excited at 488nm) and also very low absorbance.  M9 medium can be supplemented to produce higher growth rates or to allow growth of strains that require additives (e.g. thiamine or casamino acids).
<tr>900 ml sterile water</tr>
<tr>100 ml M9 salts stock solution</tr>
<tr>1 ml autoclaved 1 M MgSO4</tr>
<tr>0.1 ml autoclaved 1 M CaCl2</tr>
</table>




'''M9 stock solution''' (10x) is:
A general discussion of minimal media for E. coli is given in this article (not online or in Pubmed): Pardee, A. B., F. Jacob, and J. Monod. 1959. The genetic control and cytoplasmic expression of "inducibility" in the synthesis of ß-galactosidase in E. coli. J. Mol. Biol. 1:165-178.
<table>
<tr>60 g Na2HPO4 x 7 H2O</tr>
<tr>30 g KH2PO4</tr>
<tr>5 g NaCl</tr>
<tr>10 g NH4Cl</tr>
<tr>water to 1000 ml</tr></table>
autoclaved


M9 medium also exists in various flavors:
==Variants==
*[[M9 medium/minimal|M9 minimal medium]]
*[[M9 medium/supplemented|M9 supplemented media]]
*[[M9 medium/with agar]]


'''M9-glu''' contains glucose: In the basic recipe take 800 ml sterile water and supplement with 100 ml 20% (w:v) sterile filtered glucose before adding M9 salts, magnesium and calcium salts.
[[Category:Material]] [[Category:Escherichia coli]]
 
[[Category:Defined Media]]
'''M9-CA''' contains casamino acids: In the basic recipe take 800 ml sterile water and supplement with 100 ml 10% (w:v) autoclaved casamino acids (in water) before adding M9 salts, magnesium and calcium salts.
 
'''M9-CAglu''' contains both: In the basic recipe take 700 ml sterile water and supplement with 100 ml 20% glucose and 100 ml casamino acids before adding M9 salts, magnesium and calcium salts.
 
''Warning: salts that are added last often tend to precipitate. I didn't bother about it too much as obviously it didn't influence bacterial growth. There might be a way to avoid precipitation (eventually adding magnesium and calcium first) but I didn't investigate this in detail.''

Latest revision as of 08:40, 11 March 2008

Introduction

M9 medium is a minimal growth medium used for bacterial cultures. It has the advantage of being cheap and has a very low autofluorescence (when excited at 488nm) and also very low absorbance. M9 medium can be supplemented to produce higher growth rates or to allow growth of strains that require additives (e.g. thiamine or casamino acids).


A general discussion of minimal media for E. coli is given in this article (not online or in Pubmed): Pardee, A. B., F. Jacob, and J. Monod. 1959. The genetic control and cytoplasmic expression of "inducibility" in the synthesis of ß-galactosidase in E. coli. J. Mol. Biol. 1:165-178.

Variants