Worm-o-ween Series: Worm Maintenance Guide

Welcome back to this spooky worm blog! Now that we’ve been over all the basic information about nematodes, we can talk about what it takes to keep them happy and healthy in your lab! Even though the Halloween season is scary, these worms are very sweet and easy to take care of!

I just received my worm plates, now what?

Once you receive them, you will want to observe them under a microscope. We suggest a top illumination or bright field microscope with 20-40X magnification. Note that a dissecting microscope with the same magnification would also work. Under the scope you should see worms at different larval stages, moving freely around the plate. The worms you have received were fed right before shipment, so they should be okay without food for another couple days. As a rule of thumb, feed the worm plates every 5 days. Consistency will help you keep your worm plates healthy!

NGM Plates, Seeding and Chunking

Pouring Plates: The NGM media comes in a ready pour bottle, and is prepared similarly to how our LB ready pour bottles are made. It is much lighter in color, almost white. You break the agar into chunks by squeezing the bottle and heat it in the microwave until it completely melts. When cooled, you will add NGM salts to finalize the NGM recipe before pouring plates. Use the same aseptic technique you have used in prior experiments to pour these NGM plates. After plates solidify, use directly or store inverted and in a plastic bag inside a refrigerator. These plates will last around 1 month if stored in a refrigerator. 

Seeding Plates: To seed a plate means to add a food source on a plate. As we talked about in the last blog post, the worm food is OP50 bacteria. Create your bacterial culture as indicated in your literature directions. Typically you are adding a few OP50 bactobeads in recovery broth and incubating the culture at 37°C for a few hours. You can simply pipet around 200 uL of the bacterial culture on a NGM plate and swirl to distribute the culture evenly on the surface of the agar. Incubate the seeded plates at 37°C for 24 hours. After the incubation, the plates are ready to be used during chunking. 

Chunking Plates: Chunking is where you use a sterile loop to move a chunk of agar from an older plate to a newly seeded plate. The chunk can have hundreds of worms in it. Using your worm source plates that you received, you will cut out small cubes (or chunks) that are about 0.5 cm by 0.5 cm in size. Using a sterile inoculation loop to cut out the chunks. Use the loop side and gently press down to make incisions in the agar. Watch the clip below to see how you can cut a chunk! Once cut, lift the chunk from the bottom with the loop and gently flip the chunk worm side down onto one of the seeded plates. Within a few minutes you will be able to see the worms crawl away from the chunk, and out onto the food spread on the NGM through a microscope. This is a great sign. Store chunked plates in the same place that the worm source plates were being stored. Incubate the chunked plates for a few days, checking on the progress daily. Once there are around 50 or more worms on a plate, the worms are ready to be used for an experiment. 

Feeding Plates: Every 5 days your worm plates will need to fed. It is very similar to seeding plates, except you already have worms inhabiting on the plate! You will pipet around 200 uL of OP50 bacterial culture on the plate and swirl the plate to evenly spread the bacteria. In a few minutes the culture will absorb into the plate and you worms will be all set with their food source for the next 5 days.

Having any Issues?

Worms are moving slowly: If the worms are moving slowly they might be headed for a dauer stage. In this stage, the worms basically shut down their bodies so that they can survive unfavorable conditions (like when a plate has no food). In this scenario, you should pipette around 200 uL of OP50 bacterial culture to the plates to feed the worms. Feed them again in two days. After a week or two, these worms should be back to their active selves.

Worms are visible in the chunk but not on surrounding plate: This can be part of the dauer stage as well. This can happen because you chunked a dauer stage plate and they struggle to assimilate to a new environment. Consistency is key here again. Keep feeding these plates every two days. It may take a couple weeks, but eventually the worms will return to their active or normal state.

A Few Tips

• When seeding plates, let plates warm up to room temperature if they were stored in the refrigerator. To speed up the process place the plates in a 37°C incubator for 20 minutes. Warming the plates will let the OP50 bacteria culture absorb into the plates a bit easier. Also make sure to warm up the OP50 bacteria culture in the 37°C incubator for 20 minutes.
• Keep the worms plates in a card box box. It will be a cool and dark place to store them and keeps them isolated to prevent contamination.
• If you see the volume of the agar start to decrease, it is a sign that you should start chunking the worms onto new plates. With time, the agar dries out and slowly reduces in volume until it is a very thin layer. Chunking them quickly after you see this happening will help prevent worms from going into a dauer stage.

Tune in next week for troubleshooting advice and our FAQs! Check out our Instagram and Facebook to find the answer to the joke of the week!

Joke of the week: What did the worm say when he got stuck in the pumpkin?