Today’s Goals

Describe the advantages of C. elegans as a model organism

Discuss the life cycle of the nematodeSafely and effectively culture a

population of C. elegans and transfer worms to new plates for experimental studies

The model organism: Caenorhabditis elegans

Electron micrograph of a C. elegans hermaphrodite

Small = about 1mm in sizeLives in the soilNematodeEats bacteriaCan be male or hermaphroditic

Self-fertilizing!

Caenorhabditis elegans

Profile

Soil nematode, EukaryoteGenome size: 100 MbNumber of chromosomes: 6Generation time: about 2 daysFemale reproductive capacity: 250 to 1000 progeny

Special characteristicsStrains Can Be FrozenEasy to growHermaphroditeKnown cell lineage pattern for all 959 somatic cellsOnly 302 neuronsTransparent bodyCan be characterized geneticallyAbout 70% of Human Genes have related genes in C. elegans

Lifecycle of a worm

(from www.wormatlas.org)

Anatomy of a worm

(from www.wormatlas.org)

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 chemotaxisMove 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. elegansSydney BrennerJohn SulstonBob HorvitzAndrew FireCraig Mello

http://park.itc.utokyo.ac.jp/mgrl/IINO_lab/Eng_figures/Fig4.JPEG&imgrefurl=http://park.itc.utokyo.ac.jp/mgrl/IINO_lab/IINO_lab.html&h=491&w=333&sz=29&hl=en&start=23&um=1&tbnid=6D_KWwsfwR_pZM:&tbnh=130&tbnw=88&prev=/images%3Fq%3Dc.%2Belegans%2Bchemotaxis%26start%3D20%26ndsp%3D20%26um%3D1%26hl%3Den%26client%3Dsafari%26rls%3Den%26sa%3DN

How will we be working with C. elegans?We will be following along with lab

protocols from www.silencinggenomes.org 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 MutantsUniversity of MinnesotaCaenorhabditis genetics center7$ per strain

http://www.cbs.umn.edu/CGC/

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