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tripchip
The Mushroom Monkey
Registered: 07/07/08
Posts: 1,154
Loc: African Jungle
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Re: pouring petri dishes in a glovebox. [Re: wisp]
#8961569 - 09/21/08 02:30 AM (15 years, 6 months ago) |
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Quote:
tripsis said: No, you buy the lids separately. From that site they're another $3.50 for 50 lids. You'd be better off buying from an American supplier if that is where you are.
I don't like petri dishes for the fact that they are single use and not recyclable. Glass is an alternative, but expensive and breaks easily.
thanks for the tip. i may invest in some of these in the future. seems it will make the process a bit easier. 1 less step in the process. plus re-usable.
-------------------- Psilocybe Cubensis Psilocybe comes from the Greek root "psilos" meaning bald head and Cubensis because it was first recognized as a new species from specimens collected in Cuba. CHIP
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wisp
Registered: 04/13/08
Posts: 5,304
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Re: pouring petri dishes in a glovebox. [Re: tripchip]
#8961597 - 09/21/08 02:39 AM (15 years, 6 months ago) |
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Yeah, they are handy. Being able to sterilise the agar inside them is advantageous in reducing the chance of contamintion, although without a flowhood you'll find H2O2 agar to be of great use. As H2O2 is not autoclavable, you'll need to pour the agar after sterilisation. These PP containers are much cheaper in the long-run too.
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RogerRabbit
Bans for Pleasure
Registered: 03/26/03
Posts: 42,214
Loc: Seattle
Last seen: 1 year, 1 month
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Re: pouring petri dishes in a glovebox. [Re: wisp]
#8962533 - 09/21/08 09:52 AM (15 years, 6 months ago) |
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What a pain in the ass to sterilize agar in a petri dish or other small container. In addition, instead of one potential path of contamination(whiskey bottle with a filtered lid) as the agar mix cools and contracts(shrinks-thus drawing in air to replace the volume of agar), you have 20 or more. Not a good idea if you're looking for the highest rate of success. Besides the above, you need vented lids. Mycelium MUST breathe.
Glass petri dishes are total crap for our use, because we go through so many dishes very rapidly when isolating strains, or isolating healthy mycelium away from contaminants. I donated hundreds of dollars worth of Pyrex glass petri dishes to a local school years ago. They're environmentally unsound because you use polluting soap to wash them and LOT'S of fossil fuel energy to re-sterilize them. Plastic petri dishes can be re-used for whatever you want such as keeping spore prints, or you can recycle them at your local recycling center. I've given hundreds away to boys to keep their bug collections in, and girls like them for beads and other jewelry.
I mix agar nutrients weaker than most recipes call for. We're not using agar to expand mycelium, but rather to clean up our cultures from contamination. For this reason, the nutrients are not as important. Mycelium will grow faster and more rhizomorphic on a less nutritious media. When the time comes to expand the mycelium, use grains and grain to grain transfers.
In the DVD, I used pre-mixed agar from FP. Sporeworks also has an excellent MEA, but I was out at the time, so used some FP agar mix I had(you'll notice I turned the jar so the label didn't show . In real-life, I mix my own, but for the new growers watching the DVD, I wanted to make it as easy as possible, while still getting good results. Once you gain a bit of experience, mix your own. Use 20 grams of agar-agar per liter of water to solidify the mix, but use less nutrients than the recipes call for, for the reasons stated above.
Peroxide is toxic to fungi, ALL fungi, so the last thing you want is peroxidated agar. You're supposed to transfer healthy mycelium away from contaminants, not hide or prevent the contaminants from growing temporarily. You actually WANT the contaminants to grow on your agar so you can see them and get your mycelium away. Antibiotics are a great addition if you're trying to isolate mushroom mycelium from an outdoor fruit that is laden with bacteria. Antibiotics, which are made from mycelium metabolites, won't impede your mycelium, but WILL impede bacteria. RR
-------------------- Download Let's Grow Mushrooms semper in excretia sumus solim profundum variat "I've never had a failed experiment. I've only discovered 10,000 methods which do not work." Thomas Edison
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wisp
Registered: 04/13/08
Posts: 5,304
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Re: pouring petri dishes in a glovebox. [Re: RogerRabbit]
#8966847 - 09/22/08 03:30 AM (15 years, 6 months ago) |
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Have you used the containers I'm talking about RR? They work absolutely fine, vented or not. What you say about air entering as the agar cools makes sense in theory, but in practice I have seen no contaminants form on dishes sterilised with agar inside them if they are left unopened.
Personally I think pouring 100 dishes in a glovebox in more of a pain in the arse than sterilising 100 dishes with agar inside them. Perhaps for those with a flowhood, pouring agar is a painless activity. As I only have a glovebox, I find pouring agar in large quantities to be an exercise I'd rather avoid.
As for recycling disposable plastic petri dishes, I don't know how it is in America, but here in Australia polystyrene cannot be recycled. Using 1000's of plastic dishes each year, just to throw them out, is completely environmentally irresponsible. Giving a few hundred away to be reused for other purposes doesn't justify the many hundreds more that are thrown out.
The very fact that peroxide is toxic to fungi is what makes it so useful. Mixed at the correct concentration, mushroom mycelium will adapt to its presence in agar, but it will kill any mould spores present. I don't recommend it for prolonged use or all of the time, but it is very useful in some circumstances.
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tripchip
The Mushroom Monkey
Registered: 07/07/08
Posts: 1,154
Loc: African Jungle
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Re: pouring petri dishes in a glovebox. [Re: wisp]
#8966965 - 09/22/08 05:09 AM (15 years, 6 months ago) |
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yep ill stick to the plastic dishes. i agree with RR.
Tripsis, get a bigger glovebox. yes its is a pain in the ass to work in one. I need to go larger myself. Ill be on the lookout for something bigger than what i got and mines pretty large. i may make my own using sheets of plexi glass. if its big enough its quick. I can pour 25 dishes in a few minutes, slip my arms out, cover the holes up where my arms whent through, and then come back to them when they are cool. Mine is a decent size but im going to go larger so i dont feel so cramped in the one i have. If your way works for you than thats all that matters. I hate cleaning so pre-sterilezed dishes are great for me. pouring from the whisky bottle works great so far and is the easiest part. I load everything into my gloves box, spray it down with bleach water, come back in 30 minutes and then im only pouring and messing around inside the glovebox for 5 minutes. ill re-enter and do what i gotta do when they are cool.
Today i made some more PDA. I poured 20 more dishes for future transfers. Plus i want to see how easily they contam. Im kinda experimenting with them a bit since im new to it. im going to let them sit around for a week and then see how well my sterile procedures were. im betting on very little contamination in any.
ill make transfers from the first batchmto the new ones. The dishes I just made are going to sit for a bit so I can see how sterile my techniques were. Ill use the ones that show no contams when im ready for them. or as easy as it is i can make new dishes.
Is there a time frame on when these dishes have to be used after I pour them? i dont think so but a comment on it would be appreciated. they'll be stored at room temp untill use.
i was bored today and as easy as making the agar and pouring the dishes were i just did it for fun
-------------------- Psilocybe Cubensis Psilocybe comes from the Greek root "psilos" meaning bald head and Cubensis because it was first recognized as a new species from specimens collected in Cuba. CHIP
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