Agar-Liquefying Contamination

Model Organism: Worms Methods & Reagents
1

Hello all,
Is agar-liquefying contamination of NGM plates generally due to fungi or bacteria?
Thanks!

2

Hi,

the plates should be fairly resistant to breakdown, although acids do a good job.

BUT, you didn’t happen to store the NGM plates frozen before using them did you? :o

Steve

3

I have had plates freeze before, but this is only following passaging of worms onto the plates. It seems to be spreading to labs on different floors, even though equipment doesn’t. I think it is in the air this summer.

4

I’ve had mushy/soupy plates before, but they were old and I guess the agar was beginning to break down. As Steve says, NGM plates are pretty resilient though.

edit: It might be a long shot, but have you checked if your agar is ‘expired’ or has been exposed to high humidity?

Certain brands of agar can be total crap after their expiry date, especially if humidity gets to them…

5

another possibility is if your autoclave is playing up. Excessive autoclaving of agar medium also produces what you describe. Check the programme times etc.

If it’s spreading to other floors then it might be something you share (like old agar or autoclaves) as much as a mystery contamination :-\

Steve

6

Thanks - we are having autoclave problems and it is very humid in the building sometimes. I have some unopened agar I will try once Virginia cools down and the building can handle the humidity.

7

I believe this is bacterial contamination. After obtaining strep-resistant OP50-1 and putting the worms on NGM strep plates the agar stops dissolving. The contamination seems to spread through ethanol when chunking and through the air.