After collecting more worms during extremely low tides, we have spent a lot of time in the lab processing them. We took an assembly-line approach to photographing, taking sections of worms for DNA analysis, and preserving the head/front half of worms. Photographing the worms takes both skill and luck on our part and cooperation on the worm’s part. We have to be sure that the lighting is just right and that the camera is focused so that the worm’s few identifying features are sharp. No matter how great the preparation is, we still need the worm to hold still, which is not something we can control. However frustrating this can be, seeing the images on the computer makes it worth the effort. Without these images, our identification guide would be vastly inadequate by failing to show the visual stunningness and very minute details of worms that can be used to tell species/complexes apart. I have spent most of my time this week cutting bits of the posterior (back) end of worms off for DNA analysis. After cutting each section off, I put it into alcohol and then into a freezer so that we can extract DNA from the preserved tissue in the coming weeks. I also spent some time preserving the other (anterior, or front) part of each worm into formalin, a fixative we use to keep the tissue from degrading. We then store this portion of the worm in a museum in case anyone ever wants to look at them and their insides. Many of these morphological vouchers (the preserved front part of a worm) came out very well, which was very pleasing for me. Since I will be working with the class Hoplonemertea, I will examine the stylets (a dagger Nemerteans use to inject venom into prey) of various species and cryptic species complexes. Hence, I have been extracting the stylet-region of the proboscis (what they use to launch the stylet into their prey) from worms this week. Like many other aspects of working with Nemerteans, this part is conducted under a microscope. I have spent more time using microscopes this week than I ever have before and am becoming very comfortable with them. I thought that extracting the proboscis would be easy after watching Svetlana (my mentor) do it effortlessly, but there is definitely a learning curve to it. But patience and perseverance have paid off, as I am now able to extract the stylet-region of the proboscis intact. When I placed my first stylet under the microscope and saw that it was photograph-ready, I found Rebecca (my lab partner) and told her because I was so excited. I have begun to realize that no matter how straightforward I think something will be, it can easily become more complex. Before preserving one of the exceptionally long worms, I had to untie the knots in it under a microscope for about 20 minutes. Typically we can just put the worm in a chemical that preserves it, so this extra step was definitely unexpected. I did not plan to untie a worm with forceps when I woke up that day but it was very satisfying to successfully untie the worm without breaking it. Such is the life of a Nemertean scientist. We will continue processing worms in the next week and begin circling back to the molecular side of the project soon. I will get a lot more practice preserving worms and looking at their stylets next week, so I will be a pro by the end of the program. Updates will be forthcoming.
2 Comments
Ana
7/7/2021 08:47:00 pm
I am curious about how often they lose and have to replace the central stylet. Also can they grow additional spares, or once they run out they run out there ere no more?
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Deena Ligorria
7/8/2021 08:33:34 pm
I never really thought much about worm diversity beyond the Nematodes in Sponge Bob... UNTIL NOW! I have to admit those stylets on your ribbon worms are pretty darn cool! Looking forward to future updates.
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AuthorI am Jacob and am from Rancho Cucamonga, CA. I am a rising Junior at Pomona College in Claremont, CA who has never studied marine biology in school before but has always been interested in it. I am incredibly excited to spend the next two months working in Svetlana Maslakova’s lab studying Nemertean (ribbon worm) biodiversity through genetic analysis. Archives
August 2021
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