i am interested in doing a movement assay to determine if a mutant moves slower then wild type. i was thinking about using the parallel wormtracker program. in their methods they used filter paper soaked in CuCl2 as a corral. Wormbook says that you can also use Copper rings. Are their benefits to either method? Or is their an easier way?
http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0002208
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC420456/
thanks,
jason
Although I haven’t used it I’d recommend trying the filter paper soaked in copper (I am assuming you cut a hole in the middle and that’s where the animals go when you lay the paper onto a plate). I have used the copper ring technique, and its a little trickier & time consuming. you have to heat the rings and then lay them the agar surface so that they melt a little ways into the agar in order to form a tight seal. Its a little bit of a delicate operation. You don’t want to introduce holes or breaks in the agar that animals can burrow into, and you don’t want them to go under the ring where you can’t see them. But be warned with either technique (filter or rings) that the copper will leach into the plate and modify animal behavior. Copper is a repellant and animals are likely to display dispersal behavior (high speed, low turning). Then again, that kind of “stressed” environment might better allow you to observe differences in locomotor capability . . .
Following up on this old post, we’ve started trying the copper ring method and are having a problem with the copper that leaches out.
There is enough to turn the agar blue and make the worms visibly sick.
We’ve tried acid washing and repeated cycles of heating/cooling, but still have the same problem.
Any advice to keep the repellent effect without poisoning the worms with excessive amounts of copper?
Thanks
just woken up, so my reply was delayed. We tried out several alternatives as corrals (the so-called Macedonian solution), mainly for the reason already alluded to that copper ions will change movement behaviour.
We tried:
stainless steel washers: they work well as a physical barrier for a short assay. Must be bedded properly to avoid burrowing under the washer.
plastic (PP) washers: also ok, but obviously more difficult to embed, so some worms get under.
fibre tap (sorry for our cousins, faucet) washers: also work well, with the added advantage that one can turn the washer flat on the agar surface to embed as they are rough.
Jonathan: If you only can get copper washers at your local hardware store, then you could try painting the washers with enamel?
Steve
Using 4M fructose as an osmotic barrier around the edge of a small (35 mm) plate also works well. 60-80% glycerol is easier to make and also works. We add a bit of bromophenol blue to it so you can see it well. If the plates are too wet it will dilute the effect and it won’t last forever.