By - DirtyHarry133
So sry for the sh***y pics.
I've made these transfers from some bacterial plates and this is what i observed. The initial plates had this gorgeous ropey myc spread out at the ends.
Apparently myc makes these ropey formations to escape contam.
Idk what the bacteria is called but it just grows a very slim transparent layer over the agar and makes it look matte
It's hard to see your plate and in this case you may have contam, but rhyzomorphic growth does not necessarily indicate bacteria. The hyphal threads are not trying to escape contam, they are searching for nutrients. Also, when a transfer is made to a new agar plate sometimes the wedge/piece gets tossed around, and so growth coming in from multiple different spots can unintentionally occur where material dropped.
Furthermore, the matte cover/slim transparent layer on some areas that the rhyzomorphic growth seems to avoid does not necessarily mean contam either; sometimes the agar has not set well or the nutrients are not uniform throughout it.
I used to wonder about this as well, as my agar plates weren't always perfectly circular and there were often spots the myc seemed to avoid. I eventually got a microscope and examined sections from many different plates. While I'm not a microscopy expert and there is always a degree of error, I was pleased to find that these weak-growth spots did not actually contain bacteria or other contamination! So that's what I'm basing my response on. If you're worried though you can always transfer to a new plate! Mush love ✌️🍄💓
Edit: also you can try adding food coloring to your agar as it makes spotting these things much easier, I like to use blue
Great tip on the food dye
While i agree with you overall it's not the case here. The myc was riding the "slime" like crazy it wasn't avoiding it and the contam was very obvious on the initial plates and got less slimy and more matte with each transfer.
Of course rhyzo doesn't mean contam generally speaking but if you transfer to 2 different plates (from the same batch) from the same initial batch there's a high chance that one won't grow rhyzo and the other tomentose unless there's bacteria.
Thanks for the info. It always happens to me. I dont know how to erradicate that thin transparent layer on my agars...
To me it only happened while my pressure cooker wasn't hitting 15psi (it was pbb around 10psi)
Somebody from r/contamfam told me that it also happens if there is too much condensation. Sometimes the pc doesn't rly kill all endospores so when there's too much condensation in the plates the bacteria spawna and grows way before the mycellium has a chance to.
But i'd say that's quite rare if u do 30min @ 15psi
My PC just hits 12psi. So i keep it for an hour.
It myght be the condensation. Thr thing is that i let the bottles with agar cool so i can handle them with bare hands. Pour and close.
But i see condensation forming a minute after closing the lids.
How could i prevent this?
Thanks for the answer!
Theres not much to fix luckily 🤙 there’s usually always condensation in mine but putting a mug of hot water on top of the dish for a few will remove that condensation
Well i guess that might be the problem, the pc reaching just 12 psi. I know there's that timetable where time+pressure equal sterilisation and you cand compensate pressure through time but from my experience whwn it doesn't hit 15psi,there tends to be trouble. In regards to condensation try stacking the plates one over the other as soon as you pour them, that usally helps alot. Otherwise, (if you're sure that your SAB technique works well just let the plates cool and then pour the excess condensation from each plate.i do that sometimes with pre-poured jars. Hope this helps!