Good day to everyone. I am really in need of clarification from the gurus here about what could be happening in the experiment am carrying out. I am carrying out a life span assay, but the problem is that when I started the experiment, I picked the initial number of L4 worms I want and I added them to the plates containing the toxin of interest, OP50 lawn and the reproduction inhibitor (5.FUDR). After two days when I went ahead to count the number of live and dead worms, I found out that the number of live worms decreased across all plates but only on two plates did I find the dead worms, in this case just one per plate. Same disappearance of worms is noticed after 4 days. Yet the decrease in number of worms was general across board. I am wondering if similar events has occurred before to anyone else here and to ask is it possible that the worms are getting dissolved by the toxin I have on the plates? I checked on the wall of the plates and I can’t find them there.
Secondly, one more thing I notice is that some of the worms avoid staying on the surface of the agar, they crawl under it and move around there. Am I right by retrieving them from under the agar and adding them to the number of live worms while transferring them to fresh plates?
I would really love to get a feedback as regards these observations I have from you guys. Thank you very much in anticipation.
About 2 days into the lifespan experiment a lot of worms crawl up the side of the plate and desiccate - always check the side of the plates. They occasionally make it onto the lid. You need to censor these worms as they don’t die because of the normal ageing process.
I like to always write in my lab book:
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alive
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dead
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bagged
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crawled up side
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lost
Unfortunately you do occasionally lose worms. If you can’t find worms, look under higher mag on the lawn, and brush your pick along it. Sometimes the worms go very see-through when they die, and if you brush against the cuticle with the pick it becomes more obvious.
Unless there’s a very good reason to use FUDR (e.g. your worms have a very high incidence of bagging) you should not be using it.
If it’s easy to get the worms (e.g. they’re only slightly down the side) I sometimes retrieve them provided that can be done without damaging them. You have to consider however that if they are very deep/under the agar, they could have been away from food for a while. In that case best to leave them behind.