Yellow MOPS - why?

tfitzwater at tfitzwater at
Mon Mar 27 14:20:39 EST 2000

>Subject: Yellow MOPS - why?
>From: Wolfgang Schechinger (Wolfgang.Schechinger at
>Date: Tue 21 Mar 2000 - 16:49:36 GMT

MilliQ water stored in carboys can become contaminated with DEPC-resistant
mildew RNases.  One person adding water to a flask containing LB powder (or
any other bacterial media) generates aerosols that contaminate the carboy
spout and allow the growth of mildew.  If pink slime is growing in the
spout, bleach the spout and rinse well before reuse.

I avoid RNase problems by replacing the tubing on the MilliQ dispenser with
Teflon tubing.  Water from carboys is restricted to uses other than working
with RNA.  Anything destined for use with RNA uses water directly from the
MilliQ machine.  I have not used DEPC for over 15 years.

Tim Fitzwater
Gilead Sciences


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