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

Use of Model Organisms in Biotechnology Studies Many model organisms available - here are some common ones: Single Celled organisms Bacteria, yeast What would they be good for? Animals Drosophila melanogaster, Xenopus laevis (Frogs), Mus musculus, Danio rerio (zebrafish) What can we observe with these organisms that we can’t observe in single celled organisms? Plants Arabidopsis thaliana

What makes a good model organism? Ease of cultivation Rapid reproduction Small size

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

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

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

Lifecycle of a worm (from

Anatomy of a worm (from

C. elegans cell division can be studied in the transparent egg

C. elegans cell lineage is known

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

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!!!

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

grefurl= &h=491&w=333&sz=29&hl=en&start=23&um=1&tbnid=6D_K WwsfwR_pZM:&tbnh=130&tbnw=88&prev=/images%3Fq%3D c.%2Belegans%2Bchemotaxis%26start%3D20%26ndsp%3D2 0%26um%3D1%26hl%3Den%26client%3Dsafari%26rls%3De n%26sa%3DN

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

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

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