nematode and water bear

Caenorhabditis elegans Resources


I created this page as part of my involvement in the Science Education Partnership program at Fred Hutchinson Cancer Research Center while I was a grad student in Jim Priess's Lab. Every summer, nearly two dozen teachers are invited to FHCRC for an intensive 13-day session. Nearly half of the session is spent in the SEP Teaching Lab, where teachers practice basic techniques in molecular biology (pipetting, PCR, gel electrophoresis, etc.) and learn about resources available to biology teachers. Teachers complete a research project under the guidance of a scientist mentor at one of several host sites. In addition to helping teachers with their project, the graduate-student mentors prepare a seminar series on a topic of interest. The following information comes from our seminar series, "Model Organisms.

Any questions, comments, broken links, etc.? Feel free to e-mail me ().


Background Information, Databases and Resources



The Worm Breeder's Gazette



Caenorhabditis Genetics Center

C. elegans movies

NCBI Bookshelf

Textpresso for C. elegans

NEMAPLEX: The Nematode-Plant Expert Information System

Model Organism Week: Getting to Know Your Worms (C. elegans)

The tiny worm with the big impact

Society for Developmental Biology Education Links

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What can worms teach us? Profiles of scientists and their research

Sydney Brenner

Web of Stories: Sydney Brenner

Sydney Brenner Memorial

Ellsworth C. Dougherty

Cynthia Kenyon: 'The idea that ageing was subject to control was completely unexpected'

Lois Edgar's Experiences

Brain Science Podcast: Guy Caldwell

A Conversation with Cori Bargmann Puts Her Mind to How the Brain Works

Worms win the Nobel Prize!!

Worms contribute to another Nobel Prize!!

More Nobel recognition for the worm!!!

An Interview with Victor Ambros, David Baulcombe, and Gary Ruvkun

Worms, Longetivity and Diabetes

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C. elegans in the News and Press

Science . Vol. 282, Number 5396, Dec. 11, 1998.

Barry, Dave. "Here's the complete poop on mutant Seattle worms." Seattle Times. Seattle, Wash.; Mar 21, 1994. pg. B4.

BBC News. "Alzheimer's gene 'diabetes link'". BBC News. June 14, 2012.

BBC News. "Worm lifetime 'longer in space'". BBC News. July 6, 2012.

Cooke, Robert. "Worm's complex genome unraveled; 'Map' is big step forward for scientists." Seattle Times. Seattle, Wash.; Dec. 11, 1998. Pg. A3.

Donn, Jeff. "Enzyme that helps extend life is discovered." Seattle Time. Seattle, Wash.; May 13, 1999. Pg. A6.

Elias, Paul. "Pursuing Healthier Bacon Through Genetic Engineering and Cloning." March 26, 2006. Associated Press. [This article appeared in the Seattle Post-Intelligencer as Worm DNA gives bacon a heart-healthy boost, March 27, 2006, pg. A5.]

Grady, Denise. "A Worm's Life: Right Mutation Makes It Long but Very Dull." New York Times. New York; May 21, 1996. pg. C1.

Huntington, Rebecca. "Tiny worms may offer clues to cures for human diseases." Seattle Times. Seattle, Wash.; Jul 25, 1999. pg. B3.

Scicurious. "It's all about sex: the connectome of a C. elegans male." The Scicurious Brain (Scientific American Blog). Posted online Aug. 6, 2012.

Steenhuysen, Julie. "Genes switch altered sex orientation of worms." Reuters. Published online Oct 26, 2007.

Swaminathan, Nikhil. "The skinny on fat: you're not always what you eat." Scientific American. Published online June 4, 2008.

Sulston, John and Georgina Ferry. The Common Thread: A Story of Science, Politics, Ethics, and the Human Genome. Joseph Henry Press, 2002. This book provides Sulston's account of the development of the Human Genome Project, starting from the C. elegans sequencing project.

Wade, Nicholas. "The Four-Letter Alphabet That Spells Life." New York Times. New York, N.Y.; Jul 2, 2000. pg 4.4.

Wade, Nicholas. "An Adroit Director Of an Unwieldy Team." New York Times. New York, N.Y.; Jun 27, 2000. pg. F.3.

Wade, Nicholas. "Animal's Genetic Program Decoded, in a Science First." New York Times. New York; Dec 11, 1998. pg. A1.

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Setting Up for Your Worm Lab

Obtaining worms

The standard recipe for preparing Nematode Growth Medium (NGM) is included in Theresa Stiernagle's Worm Maintenance chapter in WormBook (Section 3.2). The entire chapter is a valuable resource for growing and maintaining worms. All reagents and consumables are readily available through most scientific-supply companies. 60 mm x 15 mm disposable petri dishes are standard for worm maintenance.

Carolina Science and Math Catalog provides a nematode "kit" that includes pre-made Nematode Growth Agar, bacteria, and petri dishes. The components can be ordered as a kit (such as catalog # 211390 or #173525), or individually:

While plates are not difficult to prepare, they can be time-consuming and pricey, depending on the number of plates needed and cost of consumables. I have had good experiences with LabExpress, which will prepare and ship several different types of worm plates.

The Caenorhabditis Genetics Center will provide worm strains and bacteria for a small fee, although exceptions can be made for teachers in secondary schools upon written request (see their website for details). The preferred bacteria for C. elegans is E. coli strain OP-50, which is a slower-growing strain than K-12. The CGC will provide OP-50 upon request. The one caveat is that the CGC is primarily a two-person operation, and orders can sometimes take up to 3 - 4 weeks to process. Therefore, it is necessary to plan ahead and allow plenty of time when ordering through the CGC. (They will not provide agar, so you would still need to buy this through another source).

I can also provide some strains to teachers in the Science Education Partnership program through Fred Hutchinson Cancer Research Center - see this page for more information.

Obtaining mutants:

Mutant worms with obvious phenotypes are not only useful in studying Mendelian inheritance or genetic mapping, but they are also just plain cool to look at. Here is a very short list of the more visually-interesting mutants:

Handling worms:

Worms are not terribly fussy about their living conditions, as long as they have a plate of bacteria to eat!

The wild-type strain of C. elegans is "N2" (these are descendants of a strain originally isolated in Bristol, England, in the 1940s). Worms can be maintained at room temperature. (If you have the ability to control for temperature, such as an incubator, 20°C is the ideal incubation temperature — at this temperature, it takes about 2.5 - 3 days from hatching to adulthood. At 15°C, it takes an extra day. At 25°C, it is about 1/3 as fast.) A plate of starved-out worms, wrapped in parafilm, will be viable for several months if kept at 15°C.

Aseptic techniques must be observed at all times! Be careful to minimize the exposure of plates to air, since fungi or airborne microbes can contaiminate a plate. While these contaminants are usually not harmful to worms, they are an inconvenience to worm researchers.

To maintain well-fed worms:

Day 1: Pour plates — prepare nematode growth medium as directed, and dispense into 60mm x 15mm plates (about 1/2 full). Allow plates to cool and solidify overnight. (Plates can be prepared up to 1 month ahead of time, and kept at 4°C. Pull plates out the day before needed and warm to room temperature). Prepare E. coli culture as directed.

Day 2: Seed plates — once plates are at room temperature, add 300 Ál of E. coli to the center of the plate. (If you don’t have a micropipetter, you could also use a Pasteur pipette or eye dropper — about 3-4 drops of culture. There should be a pool of liquid in the center of the plate, about half the total diameter of the plate). Be careful not to swirl the plates too much — most of the bacterial should be concentrated in the center, surrounded by a ring of bacteria-free agar. Allow plates to sit overnight at room temperature. Unused plates can be stored at 4°C for up to a month. Be sure to warm plates to room temperatures before placing worms on plate.

Day 3: Place worms on plate — worms can be transferred in one of two ways:

a. "Chunking" — using a sterile scapel, cut a small cube out of a plate of worms — about 1cm x 1cm. Cut from an area of the plate where there is a medium density of worms (not too high, not too low). Place the chunk, worm-side down, onto the freshly-seeded plates. Chunking will result in a plate of mixed-stage worms, which is useful for observing the continuum of C. elegans development from embryo to adult.

b. "Picking" — using a tool called a pick, made out of platinum wire melded to the end of a glass Pasteur pipet (platinum is used since it cools faster). Picking is used when you want to control for the age of the worm, ensure that all progeny on a plate are from the same hermaphrodite, or to transfer worms from a contaminated plate to a fresh plate. Platinum wire can be obtained from Sigma-Aldrich (catalog #357359) or Tritech Research (catalog #PT-9901). [Nancy Hutchison had the great idea to repurpose platinum wire from old gel boxes that are no longer being used for electrophoresis. I'd just double-check to make sure there is no ethidium bromide contamination on the wire, but otherwise, this would definitely save some money.]

note: Picking can be a challenge for some students. [I made this video to help my students get a feel for how I pick worms.] I strongly encourage students to keep trying - they will get it eventually. However, a possible alternative is to use disposable microcapillary pipets (20 - 25 Ál capacity) - draw the pipet over a flame and pull it apart to make two micropipets. Create a bore by lightly pressing the tip of a pipet against the pad of a finger, or by pinching with your fingernails. You want a bore that is big enough to draw up individual worms of the desired stage (but not too big). The Kimble brand includes a rubber bulb with a micropipet adapter (Kimble item #:71900-20, available from Fisher and other suppliers). Attach the pipet to the bulb, and draw up some liquid (a saline solution such as M9 is preferred, but distilled water works, too). While looking through the microscope, place several drops of liquid on top of the worm (enough that the worm is swimming around in the liquid), leaving some liquid in the pipet tip. Suck up the worm, then transfer to a new plate.

Day 4: Continue to check your plates daily. If any plates appear to be "starving out" (most of the bacteria has been eaten), then use the chunking method to transfer worms to a new plate. Save one starved plate as a "stock plate" to use in case you have contaminants, or your N2 strains start displaying weird phenotypes as the result of spontaneous mutations. I try to replace my stock plates every 6-8 weeks.

How to handle contaminants:

Fungal: Easiest to handle — if fungi develop on a plate, use a pick to remove worms to a new plate. Transfer worms to new plates for several days, until it is clear that no fungal spores were transferred with the worms. (Save the contaminated plates for your students — they are incredibly cool to look at under a dissecting scope! Be sure to seal the plates in parafilm first, to prevent fungal spores from escaping).

Bacterial: Sometimes, other bacteria or yeast will colonize a plate. These are easy to detect since they will be a different color than the E. coli. If there are contaminated plates, then there is a concern that worms have ingested the contaminating bacteria, and therefore will contaminate any new plates they are moved to. If you have a stock plate, then toss the contaminated plate (wrapped in parafilm), and chunk out worms from the stock plate. If not, then to remove this contamination, prepare a solution of 50% bleach and 50% 1M NaOH (sodium hydroxide). Place one drop of the bleach solution on the unseeded portion of a fresh plate. Use a pick to transfer several adults from the contaminated plate (the adults should have plenty of eggs in their uterus). The bleach will dissolve the adults (and kill any bacteria). The eggs will hatch normally, since bleach cannot penetrate their egg shell. The next day, transfer the hatched larvae to a fresh plate.

Getting Help:

Several labs in the Seattle area work with C. elegans, and the majority of these labs have at least one grad student who has been involved with the SEP program, and would be willing to help teachers. The best way to get in touch with these labs is through the SEP program. WormBase maintains a searchable list of worm labs - you can search for specific lab heads, or find all labs in a specific location.

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Applications in the Classroom: Lessons and Ideas

Silencing Genomes

U. of Washington Genome Sciences Education Outreach

"Worms are a lot more similar to people than you may think!" (The original link was taken down after Sam Ward's retirement, but this link points to an archived version hosted by the Internet Archives.)

Worm Breeding for Super Geniuses

BrainU - "Learning Neuroscience Through Inquiry Pedagogy" - resources for teachers in grades 5 - 8, led by Dr. Janet Dubinsky, Dept. of Neuroscience at the University of Minnesota. Several C. elegans-specific labs are available, including:

Understanding the Uncs! - a series of activities for high school students designed by Dr. Brock Grill at The Scripps Research Institute, Florida.

Alcohol, C. elegans and You" - Drug Abuse Research Teams (D.A.R.T.) (The original link is no longer active. This link points to an archived version hosted by the Internet Archives.)

The following articles describe methods of using C. elegans in the classroom, and were published in Life Sciences Education, an open-access journal for educators at all levels.

More suggestions for Using C. elegans in the Classroom

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