repost tips

Jyh-Shyang Kao jskao at umabnet.ab.umd.edu
Tue Feb 21 16:22:34 EST 1995


Hello! People here are so nice! After attaching to Bill Birky's request
for culture tips, I got overwhelming inputs. Thanks a lot.
There are basically three messages concerning this topic. Because I also
received a request for a copy of what I got, I have these tips organized
chronically and posted again. Have fun.

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Date: 30 Sep 1994 16:03:45 +0100
From: Olivier Vallon <vallon at ibpc.fr>
To: chlamydomonas at net.bio.net
Subject: culturing tip

I have found an easy way of getting rid of fungal infections in cultures of
Chlamydomonas reinhardtii. It takes advantage of the fact that C.r. can grow
in the presence of methionine sulfoximine (MSX, a well known inhibitor of
glutamine synthase), provided arginine is added to the medium, while most
of our unwanted visitors cannot.
If a fungal infection appears on a plate and it seems difficult to pick a
clean Chlamy inoculum, streak on a TAP plate supplemented with MSX (100
microM) and arginine (100 mg/l). If possible, place in bright light for 3-4
days, streak back on your usual medium (or a fresh TARG/MSX plate if you
want to be extremely careful). This works fine even with heavily infected
cultures. It seems to work also with bacterial infections.
I have no definite explanation why arginine allows resistance to MSX. In its
absence, 50 microM MSX are enough to kill C.r. I suspect C.r. has a high
ability to use arginine as exclusive ammonium source, bypassing NH3 and the
need for glutamine synthase.
Good luck. Let me know of problems you may encounter, or improvements, or
explanations.
Olivier VALLON

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Date: 3 Oct 1994 18:38:12 +0100
From: Antonio R. Franco </S=bb1rofra/OU=/@uco.es>
To: chlamydomonas at net.bio.net
Subject: More tips

     Talking about tips.
     Now Olivier have broken the ice, I will give another tip, and
I expect the netlanders to do the same to enrich our network.
     To get rid of bacterial contaminants, I use antibiograms discs. I
stripe a line of Chlamy cells in a TAP solid media and have several of
these discs close of such a line. This way, I can use several antibiotics
at the same time and in the same Petri dish. Tetracycline, Cefotaxime,
Trimethoprim, erythromycin, ceftixozyme are fine. Chlamy cells isolated
in this way, remain in pure cultures for a long time.

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       ____________________oOOO___|_uu_|___OOOo_____________________
      |                                 |                           |
      | Antonio Rodriguez-Franco        |   BB1ROFRA at UCO.ES         |
      | Bioquimica y Biologia Molecular |   BB1ROFRA at LUCANO.UCO.ES  |
      | Facultad de Ciencias            |   Phone: +34-57-218592    |
      | Universidad de Cordoba          |   Fax:   +34-57-218591    |
      | E-14071 Cordoba. SPAIN          |                           |
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