Pouring Agar for Simple Minds

from www.fungifun.com


These instructions will guide you through the process of pouring agar without having heavy condensation on the petri dishes.

I stack the petris in 5 or 6-piece stacks in front of the hood. Then I prepare some cups and boiling water.
I let the agar cool down to around 35 °C, just before it solidifies. Then I pour the agar in the dishes, and immediately after a stack is finished I put a cup with the hot water on top of it.
What does this do? Water vapor condensates at cold surfaces. Now, when you stack the dishes, the top of each dish is kept warm by the bottom of the previous dish. Except the top one! Through the cold top one there is a temperature gradient and the top and to some extent also the dishes underneath get some condensation.

When you put a cup of hot water on the top dish, it prevents this condensation by heating the lid.
You will also notice I put a sheet of paper in front of the hood, so the dishes donīt cool too fast from the side, which again contributes to less condensation.

I seal agar plates them with a Glad Clingwrap, where I cut a small piece off the roll with a very sharp knive.
You can use any wrap, as long it´s made from polyetylene.
Saran wrap is NOT suitable, since it´s not made frompolyetylene and is not gas permeable.
Sealing dishes prevents contaminants coming into the dish for whatever reasons, ads for easy handling since the both dish parts would otherwise come apart and allows gas exchange, since the polyethylene wrap is gas permeable.







Agar : Cloning: Archives Main : The Nook


Posted by: brainbreath Dec 11 02, 10:12 AM GMT
I haven't worked with agar before, and am wondering, when I pc it should I seal the flask or should it be left open?
Also, would it be ok to pour the plates using the flow hood, or is it preferable to use the glovebox?
Any info is appreciated,thanx smile.gif

Posted by: DirtyWOP Dec 11 02, 10:30 AM GMT
if you got a flow hood, by all means, use it!
You need some kind of filter material, like polyfil or tyvek. The flask will sick in air while it cools, so you need to filter that air. Cotton balls work too, just stuff the neck, and cap with foil.

Posted by: Fungusmaximus Dec 11 02, 12:10 PM GMT
Use a karo jar for PCing your agar works great! Flow hood if ya got one wink.gif Glovebox #2

Posted by: DirtyWOP Dec 11 02, 02:35 PM GMT
a karo jar?

Posted by: Fungusmaximus Dec 11 02, 02:40 PM GMT
The bottle I mean, the one it comes in... wacko.gif

Posted by: brainbreath Dec 12 02, 10:42 AM GMT
I got a flask from FP wink.gif
Should I sterilize the petri's? And if so, how? I got a couple of sleeves of the disposables, tried pc'ing a few last night to sterilize, and it melted the shit out of 'em...

Posted by: Iggy Dec 12 02, 10:57 AM GMT
Most plastic petris I've seen come pre sterilized. But if you must (which really ain't a bad idea) you can soak in a 10%bleach water solution. That should do the trick for you. wink.gif

Posted by: czen Dec 12 02, 11:22 AM GMT

I got some of the presterilized plastic petri dishes. Here's Nan's advice on using them:

" Presterilized plastic dishes come in packs of 20 usually. Spray the plastic sealed bag
of dishes down with lysol and put in the box with hot pressure cooked agar in a decanter.
Open the bag, pour and stack plates.
Leave everything sit in the box until cooled "

Hope this helps,


Posted by: brainbreath Dec 13 02, 11:05 AM GMT
thanx wub.gif

Posted by: 420M Dec 13 02, 01:40 PM GMT
ANNO found that if you place a WARM cup of water in a mug on top of the stack of petris that you are pouring. . .it reduces condensation.


Posted by: DirtyWOP Dec 13 02, 09:57 PM GMT
I've found that I usually have a little left in my flasks after pouring, which will have the same effect as the mug if you set it on top of the stack, since it's the same temp as the agar in the pitris....

Posted by: brainbreath Dec 14 02, 04:32 PM GMT
Thanks for the help wub.gif

Posted by: Fungusmaximus Dec 19 02, 08:59 AM GMT
Ok, I put my petri dishes in stacks inside a big ziplock for incubation and I dont get rhizo growth, just tomentose*sp* fluffy growth. I know that if myc cant breathe it fuzz's up. How can I give them enough air to have good growth, and still keep them clean??

Posted by: DirtyWOP Dec 19 02, 09:09 AM GMT
I put mine in bags and get rhizos....
but here's the real deal, what you should buy eventually
is parafilm
lab stuff
very good for sealing your dishes
and I'm pretty sure it's breatheable....

Posted by: Fungusmaximus Dec 19 02, 09:15 AM GMT
yeah, parafilm would be the way to go.
is it available w/out ordering?

Posted by: DirtyWOP Dec 19 02, 09:19 AM GMT
uhhh......not really

unless your a petty theif like me!
College labs are pretty open for snoopin' at certain times of the day....
but you gotta also be a ninja like me ph34r.gif

Posted by: Fungusmaximus Dec 19 02, 09:23 AM GMT
what do you suppose we could so for a good substitute?

What about plumbers tape? but it still couldn't breathe...
first aid tape? maybe, most def breathable...

Posted by: DirtyWOP Dec 19 02, 09:26 AM GMT
put your dishes in a filter patch bag


Shroom Glossary