Nutrient Agar

[Ophélie Queffurus]

I was wondering if you guys use nutrient agar instead of oat? I was thinking about to get some from amazon as it's cheaper than from the regular biological suppliers.I also tried months ago to make a corn stach agar but the Physarum didn't like it that much, but maybe I wasn't lucky...Also, if I use nutrient agar I need to clean up the Petri dish less often, right? Oats flakes rots quickly and that the main reason I need to change Petri dish.

Thanks!

[Heather Barnett]

There is always a trade off between providing a nutrient rich substrate for the slime mould to grow on and contamination issues. I am not a microbiology expert - if anyone else is please chip in - but I suspect that with laboratory grade nutrient agar you would need to work in sterile conditions, and depending on the environmental conditions (i.e. temperature, humidity) you mind find other things growing, with some risk of encouraging pathogens.

I haven't tried nutrient agar myself, but from reading scientific papers I think people are using nutrient agar, but I don't know under what conditions.

Slime mould is essentially nomadic. Whatever it grows on it will want to go exploring, so there is no simple solution to the moving house and maintenance issues. At least I've not yet found one. :)

[Ophélie Queffurus]

Thanks for the tips Heather!

I didn't realize nutrient agar could encourage unwanted organisms to grow as well but that make sense!

[Andrea Whitson]

I know this was 2 years ago, :-)  But, I need help for my students.

When you say the oats are rotting, do you mean you are getting invaded with actual mold as I am?  If so, have you found a solution to the problem?

I have 2 high school girls who are very interested in exploring Computer Science problems with Slime Mould, but we keep being invaded right before the results are ready for looking at.  :-(

[ian]

You could cook the oats - 2:1 water to oats microwaved until good and steamy makes a nice paste you can roll out and cut sections off. Dry toasting them might also be an option. How long is your slime taking to complete the tasks? I feed untreated oats almost exclusively and rarely get contamination but my physarum is only taking two days to colonise the food.

A stronger attractant might help - herbal sleeping tablets based on valerian are more tempting than plain oats ( the smell's not great though.)

cheers

IAn

[Jan-Maarten Luursema]

Ian's solutions are great for delaying the inavsion of your project with ambient molds, but if you don't have the resources for working sterile, you will always find some uninvited guests in your slime mold's home eventually. One other thing you could try is literally scale down the experiment so your goals will be met before the onset of visible contamination. The other molds do often have pretty colors though, and why not include them in a new series of experiments?