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 Terry M
Stranger in a Strange Land
Registered: 06/18/10
Posts: 800
Loc: Rhode Island
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 Fractional P value, and more 
#15677067 - 01/17/12 07:08 AM (4 months, 10 days ago) |
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Inspired by the 1/3 P value RR uses for his 3-section plates, I wonder if the following makes any sense. Why not take samples for a slant when a growth edge hasn't grown very much yet - say, when the mycelial mat is only 15-20 mm in diameter? I know that the P value is a crude approximation of mycelial age by equating it to mycelial growth distance. But is this any less precise?
I've noticed that if I take small samples of the growth edge before the mycelium has grown out to near the edge of the plate, the mycelium just grows around the hole, continuing toward the edge. So the argument that you might miss the signs of contamination with an early sample seems moot. If you find any such signs after the sample has been taken and the mycelium has fully grown out, you can simply junk the slant. This isn't going to happen very often anyway, so you have wasted little effort.
Assuming there is no problem with the early mycelium sampling, I'm proposing recording the approximate number of millimeters of the mycelial mat size when the sample is taken instead of the P value. If you wanted to translate to P value at any time, just divide by the 100 mm diameter of a standard plate. This can be done easily by eye simply by adding a decimal point and moving it two places.
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Obsessed with edibles all my waking hours.
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 mycoelf
Agent Of Chaos
Registered: 06/26/09
Posts: 491
Loc: hyperspace 
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Re: Fractional P value, and more [Re: Terry M]
#15677291 - 01/17/12 08:46 AM (4 months, 10 days ago) |
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I only slant cultures when I am convinced that a culture is pure, If the origin of your strain is wild clone or a multi-spore germination, the # of transfers until senescence is observed is unknown, but at least 150 to 300 transfers from the origin, I label my cultures with a P value, but never exceed 10 transfers in one year, typically I do a huge purge of plates and restart my genetics for cultivated strains in the winter anyway, and restart everything again from slants, as part of slant maintenance. I think you may be trying to quantify something this is not really measurable, P value is a relative guide to remind you to keep you genetics close to the source
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Mycoelf
I love to trade wedges. Currently looking for a nice brick top and Pleurotus Eunosmus the Tarragon Oyster. I am also getting interested in the agaricus, so if you have a cool agaricus in good genetic condition PM me please
Sterility is a process that can be likened unto infinity, which is a long walk, the closer to the end you start before beginning, the more achievable the goal of infinity becomes. Remember, cleanliness in next to goddessness
    
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Terry M
Stranger in a Strange Land
Registered: 06/18/10
Posts: 800
Loc: Rhode Island
Last seen: 4 hours, 57 minutes
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Re: Fractional P value, and more [Re: mycoelf]
#15693142 - 01/20/12 01:15 PM (4 months, 7 days ago) |
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Any other comments on this?
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Obsessed with edibles all my waking hours.
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RogerRabbit
Bans for Pleasure
Registered: 03/26/03
Posts: 37,007
Loc: USA Mountain Northwest
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Re: Fractional P value, and more [Re: Terry M]
#15693604 - 01/20/12 02:47 PM (4 months, 6 days ago) |
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I'll utter a heresy here, since as I've gained experience in commercial cultivation I don't use P value at all any more. It's simply not an accurate representation of true mycelium age.
Consider that in commercial mushroom farming we expand a tiny piece of mycelium no larger than a grain of rice on a two dimensional petri dish to more than enough three dimensional substrate to fill an over the road tractor-trailer, and then introduce it to fruiting.
Now, in relation to the above, does letting the culture grow on a petri dish for ten or fifty or a thousand dishes really make any difference? No.
I have cultures that are no more than P20, but 15+ years old and they're declining to the point they grow on media, but don't fruit. However, they're still P20.
I label my cultures with the date I made the slants, and I include the date of receipt for the original. I've found chronological time to be a much bigger factor than P value, a term Stamets' recently trademarked, by the way.
RR
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www.mushroomvideos.com
semper in excretia sumus solim profundum variat
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Terry M
Stranger in a Strange Land
Registered: 06/18/10
Posts: 800
Loc: Rhode Island
Last seen: 4 hours, 57 minutes
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Re: Fractional P value, and more [Re: RogerRabbit]
#15693669 - 01/20/12 03:01 PM (4 months, 6 days ago) |
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RR, Is this different from keeping track of the cumulative growth days, and not counting the days of refrigeration? You mentioned this recently, I think.
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Obsessed with edibles all my waking hours.
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RogerRabbit
Bans for Pleasure
Registered: 03/26/03
Posts: 37,007
Loc: USA Mountain Northwest
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Re: Fractional P value, and more [Re: Terry M]
#15693724 - 01/20/12 03:07 PM (4 months, 6 days ago) |
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That becomes awfully hard after a few years.
My practices are constantly evolving as I find methods that either don't work well, or new ones that work better than I previously did things. P value has been relegated to the dust heap of history in my operation.
On my dishes and culture slants, I no longer write down anything but the species, strain and date. I keep a separate log on all my cultures so I know the original date I received them.
RR
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www.mushroomvideos.com
semper in excretia sumus solim profundum variat
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Aleon
666
Registered: 05/26/11
Posts: 364
Loc: WI, USA
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Re: Fractional P value, and more [Re: RogerRabbit]
#15693910 - 01/20/12 03:42 PM (4 months, 6 days ago) |
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Quote:
RogerRabbit said:
That becomes awfully hard after a few years.
My practices are constantly evolving as I find methods that either don't work well, or new ones that work better than I previously did things. P value has been relegated to the dust heap of history in my operation.
On my dishes and culture slants, I no longer write down anything but the species, strain and date. I keep a separate log on all my cultures so I know the original date I received them.
RR
I like your way of thinking. When i think about it, a separate log is the way to go; im going to have to go make me another excel spreadsheet. Fun, another data log, i love making/using these things.
If the SOPA thing passed would we even be able to say P-value anymore lol!
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Everything we have ever been told is a lie.
Anybody who tells you something is lying, even me.
Seek the truth.
The highest goodness is like water.
Water benefits the ten-thousand things and does not contend.
It dwells in places that most people disdain.
Therefore it approaches Tao.
Passages from a translation of the ancient Tao Te Ching
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RogerRabbit
Bans for Pleasure
Registered: 03/26/03
Posts: 37,007
Loc: USA Mountain Northwest
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Re: Fractional P value, and more [Re: Aleon]
#15693971 - 01/20/12 03:52 PM (4 months, 6 days ago) |
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SOPA should have passed. Nobody has a right to steal. There was so much disinformation being passed around by the internet thieves and portals which enable them, it was like watching a republican debate.
RR
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www.mushroomvideos.com
semper in excretia sumus solim profundum variat
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total
Post Office Tyvek Advocator
Registered: 10/03/04
Posts: 8,353
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Re: Fractional P value, and more [Re: RogerRabbit] 2
#15694050 - 01/20/12 04:10 PM (4 months, 6 days ago) |
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I just cant even comment on that...
Sopa...Piracy...
But this isnt the forum to discuss sopa-pipa's!
Edited by total (01/20/12 04:13 PM)
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 madadi
mushroom noob
Registered: 10/06/11
Posts: 149
Loc: chicago, IL
Last seen: 4 minutes, 2 seconds
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Re: Fractional P value, and more [Re: total]
#15718812 - 01/25/12 09:27 PM (4 months, 1 day ago) |
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so i have a question that is somewhat related to the original topic. lets say i have a culture and the age is unknown. i bring the culture to fruiting conditions and i clone some to agar from the center of a resulting mushroom. is the new culture fresh? is the mycelium of 0 or 1 "P value"? if i clone a supermarket mushroom. is the mycelium as "old" as many many times it was split and grown in whatever country it was cultivated?
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RogerRabbit
Bans for Pleasure
Registered: 03/26/03
Posts: 37,007
Loc: USA Mountain Northwest
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Re: Fractional P value, and more [Re: madadi]
#15718928 - 01/25/12 09:54 PM (4 months, 1 day ago) |
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Cloning a mushroom from an aging culture gives you old mycelium with aging cell lines. If you have a culture, don't fruit it and then take a clone. Fruit it, but keep some of the mycelium back to use next time.
RR
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www.mushroomvideos.com
semper in excretia sumus solim profundum variat
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madadi
mushroom noob
Registered: 10/06/11
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Loc: chicago, IL
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Re: Fractional P value, and more [Re: RogerRabbit]
#15718970 - 01/25/12 10:06 PM (4 months, 1 day ago) |
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thanks RR for the clarification.
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trout
Flyfisherman
Registered: 12/11/07
Posts: 393
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Re: Fractional P value, and more [Re: madadi]
#15742938 - 01/31/12 01:14 PM (3 months, 27 days ago) |
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I may be wrong but I think Terry is thinking along the lines of making slants from slants to reduce the growth needed to keep a culture in storage. I know it is a small difference as RR pointed out but what about the reduced chance of contamination and ease of making a new slant to refresh a culture or just to make backups. I am about to begin making fresh slants of all my cultures and multiple backups of most. I would rather just go straight to a new slant with a small amount of myc instead of growing out a plate and then making slants from that. If I made one slant and then transferred to more backups I wouldn't have to worry about plates for all these strains that I am not going to attempt to fruit at the moment. So what are your thoughts on this. I know a plate will show vigor and any contams but wouldn't the first slant if I let it grow out just a little further than normal. If something went bad I could just dump it and make another. BTW I am using 25x150mm tubes so there is a good bit of surface area to work with.
Trout
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I need a good Hot Weather Oyster culture!!
Well things don't always look as they are and things can be misread and mistaken for what they realy are so don't read too much into what I say since I might be mistaken myself. And remember I rarely ever give a definate answer.
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Shu
Noobcubed
Registered: 11/20/11
Posts: 98
Loc: PA, USA
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Re: Fractional P value, and more [Re: trout]
#15744048 - 01/31/12 05:37 PM (3 months, 26 days ago) |
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Quote:
trout said:
I may be wrong but I think Terry is thinking along the lines of making slants from slants to reduce the growth needed to keep a culture in storage. I know it is a small difference as RR pointed out but what about the reduced chance of contamination and ease of making a new slant to refresh a culture or just to make backups. I am about to begin making fresh slants of all my cultures and multiple backups of most. I would rather just go straight to a new slant with a small amount of myc instead of growing out a plate and then making slants from that. If I made one slant and then transferred to more backups I wouldn't have to worry about plates for all these strains that I am not going to attempt to fruit at the moment. So what are your thoughts on this. I know a plate will show vigor and any contams but wouldn't the first slant if I let it grow out just a little further than normal. If something went bad I could just dump it and make another. BTW I am using 25x150mm tubes so there is a good bit of surface area to work with.
Trout
Would you switch medium on the next round of slants or keep it the same as last time?
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trout
Flyfisherman
Registered: 12/11/07
Posts: 393
Last seen: 5 days, 1 hour
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Re: Fractional P value, and more [Re: Shu]
#15746257 - 02/01/12 06:56 AM (3 months, 26 days ago) |
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I plan on switching the medium just because I want to refresh the older slants. I have not tried this yet and someone may chime in with an argument against it, but I think it should work fine.
Trout
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I need a good Hot Weather Oyster culture!!
Well things don't always look as they are and things can be misread and mistaken for what they realy are so don't read too much into what I say since I might be mistaken myself. And remember I rarely ever give a definate answer.
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