Lidstrom:MM1/MM2/MM3/HY: Difference between revisions
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== What is the difference between MM1/MM2/MM3/HY?== | == What is the difference between MM1/MM2/MM3/HY?== | ||
* They all have the same trace elements solution. The primary difference is the nitrogen source: | * They all have the same trace elements solution. The primary difference is the nitrogen source: | ||
** MM1/HY uses | ** MM1/HY uses ammonium | ||
** MM2 uses | ** MM2 uses nitrate | ||
** MM3 has no added nitrogen | ** MM3 has no added nitrogen | ||
*** MM3 is used when growing on methylamine, which releases N as it is metabolized | *** MM3 is used when growing on methylamine, which releases N as it is metabolized | ||
Revision as of 15:34, 2 May 2013
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What is the difference between MM1/MM2/MM3/HY?
- They all have the same trace elements solution. The primary difference is the nitrogen source:
- MM1/HY uses ammonium
- MM2 uses nitrate
- MM3 has no added nitrogen
- MM3 is used when growing on methylamine, which releases N as it is metabolized
If all organisms assimilate N into biomass as NH4+ why do we give them MM3?
- This is an interesting question, as the organisms must convert nitrate (NO3-) into ammonium to assimilate it. Two likely factors:
- Ammonium is too toxic
- In methanotrophs, it interferes with pMMO (methane assimilation enzyme). We don't have a tested hypothesis for why ammonium would be toxic to methylotroph.
- They prefer to convert nitrate to ammonium (using NADH) to release energy, as they have an excess of NADH due to their metabolic strategy.
- Ammonium is too toxic
Why don't we have a media with nitrite?
- It is toxic.
