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Aldicarb Paralysis Assay

This assay assesses paralysis of C. elegans over a 2 hour period scored every 10 minutes (moving/not moving). Aldicarb is extremely toxic and should be handled with care. Always wear gloved when handling aldicarb and aldicarb plates.


  • 1 mM aldicarb supplemented 6cm NGM plates
  • 4 copper rings (PlumbMaster, catalog number: 17668)
  • Tweezers
  • Bunsen burner
  • Seeded 6 cm NGM plates
  • OP50
  • Microscope
  • Timer
  • 70% EtOH
  • Worm pick

Advanced Preparations

  1. Make aldicarb plates by adding 1mL of 100mM aldicarb stock to 100mL of autoclaved and pre-cooled NGM.

    a. Mix 100 mg aldicarb into 5.25 mL of 70% EtOH to make a 100 mM stock solution. Store plates at 4°C for up to one month. Follow the NGM Plate Pouring protocol to make and pour plates.

  2. Pick 30 L4 stage worms of each strain of interest to seeded 6 cm NGM plates 20-24 hours before start of the assay.

  3. Grow 5 mL of OP50 following the Plate Pouring Growing OP50 protocol.


  1. On the morning of the assay remove 1 mM aldicarb plate from the 4°C to acclimate to room temperature. Four strains can fit onto one plate, remove the number of plates required to run all desired strains. Label the bottom of the plate above the copper ring with a shortened version of the strain name.

  2. Once the plate has warmed to RT assemble the assay plates:

    a. Ensure the copper rings lay flat on the bench (press them down flat until they do).

    b. Spray the copper rings with 70% EtOH and flame them briefly using forceps/tweezers.

    c. Quickly place the hot ring onto the aldicarb plate such that it embeds into the agar slightly.

  3. Once all four rings have been placed and cooled onto the agar add 10 μl of OP50 to the center of each copper ring. Wait 30-45 minutes for OP50 to dry.

  4. Pick 15-20 adult worms to the center of one of the labeled copper rings and start a timer once the last worm of the first strain is picked to the aldicarb plate.

    Note: Ensure worms are properly staged. Younger worms may be more resistant to aldicarb may exhibit different responses compared to gravid adults.

  5. Pick the next strains to their own labeled ring and write down the time (from the timer) which the last of each strain was picked.

  6. While waiting for the first time point (30 minutes after the last worm of the strain was picked to the plate) get a fresh seeded NGM plate and set up a table for recording data.

    Table Example:

    • Strains labeled vertically with time horizontal at the top in minutes.

    • The number of worms picked to each ring goes under time 0.

    • For each strain the time 0 is the time on the timer which the last worm was placed.

    • Calculate the time you will need to score by adding time 0 to each 10 minute time points up to 2 hours.

  7. At the 30 minute time point, and every 10 minutes after, count the number of worms moving.

    a. Under a microscope, gently tap the head and tail three times. Paralysis is defined as lack of any movement after taps.

    b. Remove paralyzed worms.

    • Flame your worm pick and take a small amount of OP50 form the fresh NGM plate and pick paralyzed worms off the adlicarb plates.

    c. Count the number of worms remaining on the aldicarb plate and record that number under the corresponding time point.

  8. After the experiment

    a. Remove copper rings from the aldicarb

    b. Flame them immediately

    c. Spray them with 70%ETOH

    d. Flame the rings again

    e. Set on bench to cool and then place back into the zip-lock bag

Note: The aldicarb plate cannot be disposed of like normal NGM plates. Set all plates used into a biohazard bag labeled with 1 mM aldicarb and coordinate their proper disposal.