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I'm determined to get these guys through a full life cycle. I'm using the Carolina strain.
Spore generation - they do need light to make spores, they need to be running low on food and starting to get a little bit dry helps. Best method I've found so far is to open their dish, place in a loose plastic bag and fold the end down lightly then leave in diffuse light, the plasmodium will migrate a little bit then sit still and produce fruiting bodies.
The spores apparently need to hang around for a few weeks in a dry place before they'll germinate - easily done.
I've read ( but not tried yet ) that they germinate best if rehydrated in wood/leaf extract made by adding boiling water to rotting wood/leaf litter, straining and sterilising. I'll try this at some point.
I got mine to germinate by mixing with tap water, adding a drop of cultured E.coli and by chance letting them dry out in the petri after a few days before adding more water and more E.coli. After 3 weeks these amoebae are still very active. I've just added one crumb of oat to the dish to see if that changes their behaviour - I wonder if lack of a suitable food source discourages plasmodia formation.
Just set up this morning - mixed spores with water to make a light purple cloudy suspension, added a few drops of E.coli and dispensed into petri dishes.
Also streaked spores out onto oat agar ( boil 5g oat in 200ml water 20mins, strain, add 4g agar, autoclave ) as they can apparently mature on this alone.
Also added some of the amoebae to an oat agar plate to see what happens.
To the see them single celled phase you need a microscope - 100 or 200 mag is fine, they're a bit on the transparent side so phase contrast or DIC is a big advantage but they will show up in bright field. They don't move massively fast - try timelapsing them at 1-3 frames per second.
Once I can figure out what attracts them and what stimulates maturation I hope to capture images of them merging.
Three dishes set up on 9/3 with spores, water and E.coli show a few amoebae swimming around this morning. The spore does petris show massive amounts of bacteria which is hardly surprising but also show clear plaques around the patches of spores. I'm hoping this means I have amoebae grazing on bacteria.
All but one dish is now a nasty looking swamp of slimy bacterial colonies. The remaining one however, although it has a splodge of bacteria in the middle has something around the outside.
The stuff growing around the edge is dense, white and not spreading in the way bugs do - it's got a slight scalloped fan pattern to it. I've expecting something that looks like physarum does in a 'text book' photo but it occurred to me this morning that the plasmodium will be immature ( so not yellow ) and that it's growing on nutrient agar so has no need to form the familiar shape we expect.
I've taken out five pieces of agar and put them onto filter paper in clean petris with a since oat flake each - I want to see if it'll grow over the oat and confirm that I've got my next generation of slime mold :)
Success! properly visible - though still small plasmodia on the agar this morning on one of the plates. The rest are just a horrible mess. Oat agar and a sparse smattering of spores seems to be the way to go. I've cut some chunks out of the plate and transferred to filter paper with a single oat each and to hedge my bets put wet oat flakes onto some of the other patches.
What I'd like to know now is whether that plate contains just one plasmodia that's spread over the whole thing or whether I've got several results of cell fusion on the plate - and therefore several genetically distinct individuals.
Congrats! Maybe you could just keep feeding the whole plate and seeing if you get individual plasmodia that won't fuse?
They turn out to be quite gregarious, I've merged the cultures because I got cheesed off with maintaining twelve petris. I also tried making one share with the parent Carolina strain and they fused after a slight hesitation. I'd like to see if that's true of distantly related strains
I've just uploaded a few microscopy vids of my last run at the full lifecycle thing, they're growing on E. coli. It really looks like there are many separate instances of mating?! I'm guessing this must be true for your plate too. This is where I get horribly confused with the genetics... these guys had to have different mating types as amoebas in order to fuse into a plasmodium, that suggests to me that the fusion loci must also vary between siblings. Perhaps they don't vary so much that they don't all fuse together again once they're diploid. Does that mean that plasmodia have genetically different nuclei all jumbled up inside? Going to have to try this again and watch for longer! After the vids I threw on oatflakes and grew as normal for a while with no obvious signs of anything competing/ not fusing - but then let them go.