immobilizing live, late-staged (pretzel) embryos for imaging

Has anyone solved this issue in an easy manner. We need to image a hypodermally-expressed transgene in late embryos but animals are way to mobile.

Any solution will be tried.


I saw a talk a very long time ago (by John White, if I recall) that proposed using a temperature sensitive muscle defect (myosin, maybe?) for this purpose, in trying to take automated embryo lineage past when the embryo starts moving. Movement must be possible for the embryo to develop, as I understand it, but you need to be able to stop it and take pictures.

That was back before there were any methods using channelrhodopsin or halorhodopsin; channelrhodopsin seems unlikely to work, because I doubt you can get retinal in the embryo (unless it can be delivered via yolk?) but maybe halorhodopsin?

I’ve started using a half-saturated solution of ‘chloretone’ to paralyze adult worms. Ten minutes knocks them out, reversibly. Maybe you could treat the fetus this way, with permeable eggshells as described by Carvalho et al 2011; PLoS One 6(9): e24656.