Is Tris a potential nitrogen source: REPORT

Xavier Reboud reboud at epoisses.inra.fr
Fri May 12 01:57:06 EST 1995

Thanks for the many answers I got for the 2 questions I asked last week.
Here is a quick summary of what I have been told:
- Is tris a potential nitrogen source for Chlamy ?
As confirmed by everybody, Tris cannot be a MAJOR nitrogen source.
Some people (as I did too) use Tris in the media inducing gametogenesis.
Now if we go into details and according to Olivier Vallon, photosynthetic
mutants can grow (but very slowly) on a Tris media. Thus Tris can be
metabolized and used as a carbon source (this however gives no evidence
that Chlamy can use it as a nitrogen source). Well, here I am !!!
- Is there any non nitrogen pH buffer (except Phosphate) ?
Here, I got also several answers. People are using HEPES (15 mM, pH 7.5),
and also MOPES and PIPES as replacements/ supplements to Tris. Those
3 however contains nitrogen.
It seems that growing Chlamy in liquid media under bubbling with
1% CO2 can maintain a steady state pH at values arround 6.8 - 7.0.
So with this exception, no tracks of any nonnitrogen containing buffer
other than phosphate.
Thanks again, Xav.
Dr. Xavier REBOUD
Laboratoire de Malherbologie, INRA, BV 1540, 21034, Dijon, France
Tel 33 80 63 31 84
Fax 33 80 63 32 62

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