another help with fatty acids

truan at cgmvax.cgm.cnrs-gif.fr truan at cgmvax.cgm.cnrs-gif.fr
Thu Mar 10 09:49:14 EST 1994


>truan at cgmvax.cgm.cnrs-gif.fr wrote:
>: group and I found them. Nevertheless I would like to know more about the
>: detergents used to solubilize the fatty acids. I have to control exactly
>: the concentration of fatty acids so Tween 80 or any equivalent have to be
>: discarded I think? I have a protocol which uses tergitol NP40 at 1% but
>: when I tried it the agar plates looked very bad. Is it possible to use
>: others detergents (like triton or anything elese) at low concentrations.
>: The other question is about liquid medium. Is it possible to add the fatty
>: acids without detergents?
>: 	Thank you in advance for your help!!
>:
>: 	Gilles   ;->
>
>Gilles,
>
>I don't want to sound snotty, but how can you possibly control exactly the
>concentration of fatty acids (FA)?  The nature of FA itself makes this a
>very difficult (read impossible) task.  Studies have been done that show that
>FA stick to glass, plastic, or whatever.  Therefore, there are naturally going
>to be concentration errors due to pipetting (or transfer in general).  Then
>there are the problems of micelle formation, interaction of the FA with the
>container being used, and breakdown (epoxidation) of unsat. FA.  All these
>affect the relative conc. in media.
>
>We use FA extensively in our research.  Normally we must titrate to determine
>what FA and how much works best for what we want to see.  Sorry I can't give
>you a more exact answer.  I will give you any and all recipies we use if you
>so desire.  Additionally, there is an excellent handbook by Calbiochem that
>gives many specifics for Detergents.  They can be reached at
>
>(800) 854-3417
>
>P.O. Box 12087
>San Diego, CA 92112-4180
>USA
>
>I by no means work for Calbiochem or are associated with them in any way.
>It is just a very handy reference.
>
>Please contact me if I can be of any more assistance.
>
>Dubear Kroening
>dubear at molbio.cbs.umn.edu

        Thank you very much for your response. Of course I am a bit
desappointed by the response but I understand the problem. In fact I have
tried to solubilize with tergitol NP-10 at 0.5% in a complete medium and
yesterday night it seemed to work but today the culture is very strange.
Nevertheless I will try to measure the doubling time of the yeast with the
Klett. I was wondering of detergents because tween 80 contains fatty acids
I think and I would like to be sure of the type of fatty acid which is
supplemented. I know that 1 mM of palmitoleate and oleate is sufficient to
abolish completly the expression of the delta-9 desaturase and that in this
case yeast uptake the fatty acids. My problem is about a double mutant 
which
could perhaps be saved with high concentrations of fatty acids. I tried to
spray FA on plates and to incorporate them in the agar and it has never
been succesfull. If you have a protocol which permit solubilisation of FA
in agar plates I would be very happy.
        Thank you again for your response

                        Gilles



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