1. Today’s Goals
Describe the advantages of C. elegans as a model organism
Discuss the life cycle of the nematode
Safely and effectively culture a population of C. elegans and transfer worms to new plates for experimental studies

2. Caenorhabditis elegans
The model organism:
Caenorhabditis elegans
Electron micrograph of a C. elegans hermaphrodite

3. Can be male or hermaphroditic
Small = about 1mm in size
Lives in the soil
Nematode
Eats bacteria
Can be male or hermaphroditic
Self-fertilizing!

4. Caenorhabditis elegans
Profile
Soil nematode, Eukaryote
Genome size: 100 Mb
Number of chromosomes: 6
Generation time: about 2 days
Female reproductive capacity: 250 to 1000 progeny
Special characteristics
Strains Can Be Frozen
Easy to grow
Hermaphrodite
Known cell lineage pattern for all 959 somatic cells
Only 302 neurons
Transparent body
Can be characterized genetically
About 70% of Human Genes have related genes in C. elegans

5. Lifecycle of a worm
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6. Anatomy of a worm
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7. C. elegans cell division can be studied in the transparent egg

8. C. elegans cell lineage is known

9. C. elegans is amenable to many
forms of RNAi treament
Fire & Mello - Won Nobel prize for discovery of RNAi
Feeding worms bacteria that express dsRNAs or soaking worms in dsRNA sufficient to induce silencing (Gene 263:103, 2001; Science 282:430, 1998)

10. C. elegans can also be used for
Behavioral studies
Will respond when tapped -
Different mutants might respond differently
Display chemotaxis
Move toward certain chemicals
Studying Neurobiology
Very few neurons
Easy to map out what neurons target each part of the body, test genetics of neurobiology
Studying Embryonic Development
Cell biology, Apoptosis
. . . And more !!!
C. Elegans in space!!!

11. Nobel Prize winners who did their research with C. elegans
Sydney Brenner
John Sulston
Bob Horvitz
Andrew Fire
Craig Mello

12. http://park. itc. utokyo. ac. jp/mgrl/IINO_lab/Eng_figures/Fig4
We have found a novel form of behavioral plasticity in chemotaxis. That is, worms starved in the presence of NaCl learn to avoid NaCl, which is normally an attractant for C. elegans. Because starvation in the absence of NaCl has little or no effect on chemotaxis, this seems to be an associative learning. While similar bahavioral changes were observed using several other water-soluble chemoattractants, chemotaxis to odorants is not affected. We have isolated several mutants defective in this form of learning and also identified several mutants already known for other defects to have defects in learning in our paradigm. We plan to clone or analyze the genes responsible for these defects.

13. How will we be working with C. elegans?
We will be following along with lab protocols from
Learn to culture and examine nematodes
Learn techniques to count and transfer worms to separate dishes
Perform RNAi, using a kit
Design experiments of our own with techniques we read about in the primary literature

14. We can order C. elegans Mutants
University of Minnesota
Caenorhabditis genetics center
7$ per strain

15. NGM Plates and OP50 broth You will pour NGM-lite plates
Pour 1 bottle per pair of students
Using Sterile Technique
Nematode Growth Medium
Label Plates NGM, Date, Initials
When solid, invert, put on lab bench by incubators
Then – take 5 microliters of OP50 bacteria, innoculate a tube of LB broth (on lab bench)
Label with your initials, and OP50, put in 37 Degree incubator
Next time - we’ll seed plates with bacteria for culture of C. elegans