M9 medium: Difference between revisions
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| 100 ml M9 salts stock solution | | 100 ml M9 salts stock solution | ||
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| 1 ml autoclaved 1 M | | 1 ml autoclaved 1 M MgSO<sub>4</sub> | ||
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| 0.1 ml autoclaved 1 M | | 0.1 ml autoclaved 1 M CaCl<sub>2</sub> | ||
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'''M9 stock solution''' (10x) is: | '''M9 stock solution''' (10x) is: | ||
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| 60 g | | 60 g Na<sub>2</sub>HPO<sub>4</sub> x 7 H<sub>2</sub>O | ||
|- | |- | ||
| 30 g | | 30 g KH<sub>2</sub>PO<sub>4</sub> | ||
|- | |- | ||
| 5 g NaCl | | 5 g NaCl | ||
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| 10 g | | 10 g NH<sub>4</sub>Cl | ||
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| add water to 1000 ml and autoclave | | add water to 1000 ml and autoclave | ||
Revision as of 02:44, 30 March 2006
We used to prepare the plain M9 medium as follows:
| 900 ml sterile water |
| 100 ml M9 salts stock solution |
| 1 ml autoclaved 1 M MgSO4 |
| 0.1 ml autoclaved 1 M CaCl2 |
M9 stock solution (10x) is:
| 60 g Na2HPO4 x 7 H2O |
| 30 g KH2PO4 |
| 5 g NaCl |
| 10 g NH4Cl |
| add water to 1000 ml and autoclave |
M9 medium also exists in various flavors:
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.
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.
