cryopreservation of physarum polycephalum

[Choi Ming Ho]

I have been finding the protocol for making frozen stock of physarum polycephalum from plasmodium stage, but I can't find any formal protocol. Can you provide me one? Also, how long can I keep it alive, ten years? I would like to keep it at least for ten years, should I keep it in liquid nitrogen or -80C?

I have found this protocol for physarum myxamoebae: http://www.physarumplus.org/Protocols/Burland/PpFrozen.html

should I use it?

A lot of questions but I desire help. Appreciated!

[Warren Tan]

I had the same intention of freezing slime mould at -80degrees for long term storage!

However I had problem trying to get slime mould to grow in liquid (tried both LB broth and oat porridge), and hence it is hard to mix in glycerol.

Freezing slime mould covered oats submerged in glycerol didn't work.

Suggestions welcome! :p

[ian]

You'd need to get them smaller and into liquid culture to stand a chance - there are details here though not of freezing: http://www.researchgate.net/publication/251181953_Microplasmodium_D...

Why freeze when the sclerotium is viable for years though? Just dry a plasmodium out on paper and cut it up. 

[Warren Tan]

Recently i tried freezing the dried sclerotium at -80°C. They recovered ok after a week of freezing, will take another aliquot for thaw-recovery test in a few months' time to be sure.

I guess that could be an option. :)

[ian]

Why freeze it all though? the sclerotia store fine

[Warren Tan]

Hi All

Welcome to September. I manged to revive the dried sclerotium kept at -80°C since July last year. :)

Placed the sclerotium on 1% bacto agar, and on the next day it is spreading out hunting for fresh oats already.

And... freezing at -80°C saved my culture. Probably because I am in warm and humid Singapore, all my sclerotium kept at ambient condition didn't revive. Oddly, that is despite my lab being air conditioned at 25°C... maybe because ambient humidity is still too high.

Warren

[Choi Ming Ho]

Thanks two of you!
I just want to make a longer term storage, as long as possible, since I will leave my university soon and maybe no one would take up the rearing job.

[ian]

Make sure you take some with you!

As for storage, since half of cryo storage is avoiding ice crystals I'd suggest freezing sclerotia as Warren has tries is the way to go - it's already low enough in water to put up with a snap freeze. I'd also just dry down a load and leave it 'ambient temperature' - which as we all know is science speak for 'we just left it in the drawer' 

You could hedge your bet and store some spores too.

[Dr Jason bell]

Left it in the draw!! You have just disclosed, one of the most sacred secrets of the science lab :D