I am hoping someone can help with this issue. We are a small lab and want to grow C. elegans in some axenic culture so that we can look at the metabolism and efflux of our compound (using MassSpec) on both the worms and on the culture supernatent after growing the worms in there for several days (week). We need to ensure that the bacteria are not doing the metabolisation.
There seems to be a variety of recipes out there. The ones which allow good growth are notoriously tricky to put together not to mention will require an outlay of thousands and thousands of $$$$$ to get all the chemicals. Our experiments, with repeats, will require a dozen liters at the most (I suspect). So, does anyone have any suggestions?? Either hints on putting together the CeHR recipe or Cb+AXM recipe. Ideally, a commercial source of CeHR or CbMM to which we could add the supplements??
Perhaps a silly question - but what happens when you culture C. elegans with autoclaved bacteria?? Is this too glooopy for them to feed on? How about, bacteria baked down and ground up?
I can’t answer your question about axenic culture, but I can say a word about autoclaved bacteria. I have used autoclaved bacteria to feed worms on plates when their original healthy growing lawn of bacteria has run out, and they seem to do ok. I have not tested using autoclaved bacteria for feeding from the get-go however, but I imagine they would get enough nutrients. It’s easy enough to test, in any case.
I remember seeing a talk quite some time ago where the speaker had been given a little aliquot of a small molecule by a friend who wanted to see if it would affect worm development, and out of similar concerns that living bacteria might metabolize the small molecule he grew his worms with dead bacteria and a dilution series giving various doses of the small molecule. In his initial experiment he neglected to include a negative control with none of the small molecule, initially leading him to believe the small molecule affected worm development. He told the story as a cautionary tale, because it turned out that what he initially thought was drug effect turned out to be the consequence of feeding his worms dead bacteria instead of living bacteria - and he could rescue the effect by adding extra magnesium. He therefore described the bacteria as being “little magic pills” that concentrated magnesium from the media so that the worms feeding on them got enough of it. So it would appear that dead bacteria can fail to provide essential nutrients provided by living bacteria; it’s likely that the method you use to kill your bacteria makes a difference (and unfortunately I do not recall what method this fellow used).
That said, as long as you check beforehand and do appropriate controls, seems like it should work.
You can grow worms on autoclaved bacteria in NGM, so long as you supplement with a heme source (hemoglobin is pretty cheap). They develop a weird bump by the rectum, but otherwise seem to grow fine.
Thanks heaps for those insights and suggestions!! I will be giving the autoclaved bacteria supplemented with a heme source a trial. Its great to have this Forum as a resource.