>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 ;->
>>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
>>P.O. Box 12087
>San Diego, CA 92112-4180
>>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 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
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