Hello,

I have the same problem but I couldn't find the source of the satellite colonies on the NGM plates. Have you found the source of the problem?

Thanks!

Same Problem here! The dots appear 3-4 days after seeding and storing in the 4 degree. This problem seems to occur randomly and I think the source must be the OP50 itself. I already thought it could be a mutation of op50 and started cultivating the bacteria from a clean frozen stock. The dots showed up anyways. I’d be glad to hear some more experience from all of you.

I see the same thing. I don't remember seeing this kind of thing before 2020. I ordered OP50 directly from the CGC and made new stock, but I still see these extra colonies, most of the time at the edge of the bacterial lawn.

I noticed that picking one of these outgrowing colonies onto a new OP50 seeded plate results in quick and aggressive growth at room temperature. The mutation may therefore have been selected by over-growing at room temperature.