individuation

[Sarah Roberts]

Many of us are using Physarum sourced from Carolina - does anyone know how many cultural lineages they have?  Any ideas about how we might think of its individuation?  Obviously each  culture will adapt and mutate a bit according to its experiences, but at what point do we call it a different individal? Are we all working with one giant international cell?

[ian]

Once they're in plasmodial form I doubt there are many changes - they're essentially cloning their nucleii so unless one dividing nucleus happens to have a massive advantage over all the others in the syncitium it's not going to propagate.

Mine was sourced from Carolina as well, I'd like to know if they ever go back to spores or if their strain is purely vegetatively propagated. I'm trying to raise from spores at the moment which will allow for sexual reproduction and some variation assuming the Carolina strain isn't massively inbred. 

I'd love to know what happens when two genetically distinct  lineages meet as plasmodia, do they merge, fight or avoid each other?

[Sarah Roberts]

I would also like to know those things. Have you tried speaking to the Carolina people?   Are you going to take the questions to the slime mould and try to raise distinct lineages?

[ian]

Well I've emailed them from my academic address, I'll let you know what they say.

[Sarah Roberts]

Ah good, thanks,  an academic email always helps. Do you have the means to look at this stuff yourself where you are?

[ian]

Here's the reply

"the source of our physarum was collected locally many years ago  and has been in culture since.  Unfortunately we have no data on sporulation by propagation this includes introduction of another plasmodium culture.  "

It does sporulate and a quick check under the 'scope this morning showed what looked to be a young plasmodium :)

I'm a microscopy suite manager - plenty of toys for looking at these little guys in detail :)

[Sarah Roberts]

Ha.  An eternal self-replication.  Well anyway I suppose Carolina are basically a shop so they have no reason to care as long as they can keep their culture going.

I'm hoping to get some Physarum to go through the whole life-cycle, to make some illustrations. It's great you got yours to form a young plasmodium. What are you using as a substrate? I had a number of sporulation events and grew a lovely new plasmodium by accident at one point. This was on some low-nutrient agar, my normal kitchen towel substrate was never so popular.

[ian]

I started with agar but filter paper is a lot less hassle. I got sporulation by leaving a petri in an autoclave bag in the light, the plasmodium ran out of food, left the dish and sporulated on the side of the bag

[Sarah Roberts]

Thanks, I'll try filter paper. (Sporulation was never a problem, I found mine ready to do that at the drop of a hat! Including on one of my paintings.)

I haven't had a chance to look in depth at the literature on Physarum's take on self- non-self questions but nothing leapt out at me so far. Might be fun to play with putting our georaphically & experientially different cultures together at some point in a rough & ready way?