Transcript C. elegans Introduction PPT Lecture

Introduction to
C. elegans
http://labs.bio.unc.edu/Goldstein/crawl.mov
Ms. Gaynor
Honors Genetics
What is a “nematode”?
• It is a round worm!
–There are other types of worms
• Flatworms: tapeworms, flukes
• Segmented (annelids): earthworms
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Caenorhabditis Elegans
(multicellular, eukaryote)
Very small round worm-1 mm long!
Hermaphrodites (male & female parts)
Life span: 2-3 weeks
New offspring EVERY 3 days
19,099 genes (small genome)
– 40% are equivalent to human genes
• ~1000 cells
• Taught us about:
– Cell suicide (apoptosis) and cell health, human
aging, cancer, neurological disorders, animal
development, diabetes
http://www.exploratorium.edu/imaging_station/gallery.php?Asset=GFP%20%3Cem%3EC.%20elegans%
3C/em%3E&Group=&Category=%3Ci%3EC.%20elegans%3C/i%3E&Section=Introduction
C. elegans- A Perfect Model Organism
• Model organism for genetic study meets certain
criteria:
– easy to grow
– short life cycle
– produce many offspring
– relatively inexpensive
– Easy to keep/feed
– easy to manipulate/mutate
• “KNOCK OUT” or “TURN OFF” genes then look
for consequences
C. Elegans Information
• Habitat
– Free living in soil
– It’s a NON-PARASITIC
round worm
• Most other round
worms are parasitic!
• Food
– Feeds on bacteria (E.
coli) in soil
– E. coli OP50 is used as
nematode food in lab
In this lab…E. coli OP50
• this strain of bacteria can NOT synthesize (make)
uracil
• Can NOT live in human gut… but still be careful
and WEAR GLOVES!!!
– No food or drink (or gum) in lab
In this lab…
• C. elegans will come in 3
different phenotypes
– WILD TYPE
– dpy-11 (“dumpy” mutant)
– bli-1 (“blister” mutant)
• We will use the wild type
strain as a control group
(comparison) in order to
identify the 2 mutants
In this lab… you will use agar plates (petri dishes)
with bacteria
• Agar
– A yellow colored “jello” made of sugar
• Agar that worms live on is called NGM-lite
– Bacteria live on agar and eat this agar, worms eat
bacteria
– A plate with bacteria on it is called a “seeded” plate
a seeded plate that is
ready for use
In this lab… “chunking”
• "Chunking" is a way to keep worms
alive and maintain growth
– Cut a 1 cm square "chunk" of agar
with worms in it from a plate with
growing worms
• Use a sterile scalpel dipped in
alcohol and flamed before and
after each use
– Transfer “chunk” to new seeded
plate
• When to use this technique:
– When you don't care exactly how
many worms are transferred plate.
When chunking, be careful of contamination…use
“pac-man” technique!
Life Cycle of
a C. elegan
A typical view of a seeded
plate…
http://www.dnatube.com/video/5962/Celegans-population
Another typical view of a
seeded plate…
•
http://www.dnatube.com/video/5961/C-elegans-responding-to-a-touch-stimulus
bli-1 mutant
dpy-11 mutant