Dear Netters,
I want to summarize our experience with freezing Chlamy according to the
protocol posted here about a year ago from Richard Sayre. That protocol
involves using 3% methanol as a cryoprotectant, slow cooling in an
isopropanol bath, and storage in liquid nitrogen. This method has worked
very well for us on a wild type test strain (R3) which gives 20-50%
survial after thawing. We have recently tried it with a few mutant
strains, including cw15 and a nic7 arg7 ac29a triple mutant. These mutant
strains were grown and frozen in yeast extract supplemented TAP. The
lowest recovery was 2-3% for the cw15 strains, but the multiple auxotrophs
seemed to recover at near wild type levels. The longest we have kept a
strain frozen is 6 weeks, and have seen no significant loss of
viability. I'd like to know what other people's experiences are with
the protocol and whether it has been further optimized since posting.
Jim Umen
Department of Biology
Campus Box 1229
Washington University
One Brookings Drive
St. Louis, MO 63130
Ph: 314-935-6855
Fax:314-935-5125
