RNAi plate odor

We are trying RNAi in our lab for the first time, and I was wondering if anyone else had encountered the same problem we are having. Our seeded plates and unseeded plates smell fine (like normal worm plates). However, a couple of days after adding worms to the plates, the plates fill the box (and incubator or lab) with an awful odor - maybe similar to sulfur? We keep our RNAi plates with worms at 20C while the seeded plates without worms are kept at room temperature. Any suggestions would be much appreciated.

Thank you!

IPTG, C9H18O5S, is the most common inducer of lac promoter systems. IPTG induces the lac operon but is not a substrate for beta-galactosidase and is not catabolized by E. coli. Either the worms have additional enzymes and are breaking down the IPTG, or it is breaking down simply because of the warmer temperature in the worm incubator. IPTG contains a sulfur atom, and organic sulfur-containing compounds sometimes smell horrible, for example butane-1-thiol.

We have a small update on the RNAi plate odor:

  1. RNAi plates (from the same batch) kept at room temperature without worms or at 20C without worms do not develop an odor. It is generally warmer in the lab (room temperature) than in the 20C incubator.
  2. RNAi plates at 20C with worms develop the odor. (Possibly the worms are metabolizing one of the byproducts of IPTG?)

Our current idea is that perhaps we added the IPTG and carbenicillin to the media while the media was too hot so that the IPTG started to break down. My students are testing a new batch of plates.

Our seeded RNAi plates always smell when they get older. Its normal.