Parts of the bleaching process: A: worms in tube prior to bleaching. B: Worms in tube after first bleach spindown. C: Closeup of worms in early stage of bleaching. D: Eggs and worm residue in later stage of bleaching. E: Isolated eggs after bleaching.
Bleaching worms is is just a part of the really gross circle of life.
Nematodes are great! They take up way less space than elephants, they breed easier than pandas, and they don't have sharp teeth like mice do. These things, combined with their each-time-identical* 302 neurons makes them ideal for neuroscience research, as well as for teaching experimental biology.
I was introduced to these nematodes in the summer after graduating with my bachelor's, when I was generously invited by Dr. Alon Zaslaver to do research at the Hebrew University in Givat Ram. There, I learned the ins and outs of taking care of and murdering these wonderful little creatures, and was introduced to MATLAB by Eyal Itskovits to use machine learning for detection of multiple animals to elucidate patterns in their behavior.
media2.mp4media3.mp4Above left: TMT, trimethylthiazole, is placed at the center of an agar plate and worm positions are tracked over time. TMT is a chemical produced by the nematode food source (E. coli), so the worms initially cluster to the source of the smell. However, eventually, the worms learn that the chemical is a false signal and that there is actually no food available, and they begin to migrate away. I performed this experiment with different chemicals, concentrations, and mixes of chemicals, to see how these variables changed the "food leaving" behavior. The conclusion was that mixes of chemicals elicit a greater response, and that there is some as yet unknown mechanism for sensory integration between neurons in C. elegans.
At right, in the control, the worms spread out immediately.
This work is unpublished, and raw data of worm positions in different experimental conditions is available to those who want it (in the form of MATLAB variables).
When I arrived back in the USA the sponsorship of the Howard Hughes medical institute gave me the opportunity to apply what I had learned to teach undergraduate biology students hands-on research skills. Students had to keep the worms alive and use them for a simplified chemotaxis experiment where they tested perfumes and other smells they brought from home. I taught this class for two years and I think it was a great way for students to get exposed to what real biology was like! One student even went on with me to present the material at the Michigan Academician.
Left: Box filled with student plates from Spring 2017, LTU. For the first half of the semester, students were required to keep two strains of worm, a wild-type and rolling mutant, alive and distinct via chunking each week. The clear phenotypes of each strain make it easy to spot cross-contamination.
Right: One student wanted to see if she could “make worms fat” by adding olive oil to a plate. Surprisingly, this resulted in an increase in brood size and clumping behavior. This may be the result of sterols in the oil; C. elegans use cholesterol to synthesize hormones directing development.
Below is a google docs manual for teachers who may want to raise nematodes and do experiments for their own class. Please feel free to contact me for extra clarification.
During my Master's engineering degree, I kept nematodes in my mind for applications of the LadyBug scanning microscope. In my original design, I had a 3.5 cm petri dish like I would use for C. elegans as the spinning subject, to be scanned instead of a CD. When I switched to the linear scan style, I made a Z axis mount for said petri dish, too. The idea was that you could do research above on worm positions with a much lower investment than my lab in Jerusalem.
