Antioxidants and Worm Aging Under Oxidative Stress

ISEF Category: Animal Sciences

Subcategory: Cellular Studies  ·  Difficulty: Intermediate  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

A tiny worm can reveal how cells handle stress. When paraquat pushes C. elegans into oxidative damage, its lifespan and feeding rate can shift fast. That gives you a clean way to test whether vitamin C or green tea extract offers protection. You can turn a simple antioxidant question into a real aging experiment.

What Is It?

C. elegans is a tiny roundworm that scientists use to study aging, stress, and cell damage. Paraquat is a chemical that creates reactive oxygen species, which are unstable molecules that can hurt cells. Think of it like rust forming on metal, except the damage happens inside living tissue.

Antioxidants such as vitamin C and compounds in green tea can help block or absorb those reactive molecules. In this project, you would watch two signs of health, lifespan and pharyngeal pumping. Pharyngeal pumping is the worm’s tiny feeding motion, like a heartbeat for eating. If an antioxidant helps, worms may live longer, feed better, or both.

Why This Is a Good Topic

This is a strong science fair topic because you can test a clear cause-and-effect question with visible data. It connects to oxidative stress, aging, nutrition, and cell damage, which all matter in biology and health research. You can learn how to set controls, compare treatments, and read survival curves, which are real research skills, not just lab tricks.

Research Questions

• How does vitamin C pretreatment change the lifespan of C. elegans under paraquat stress?
• What is the effect of green tea extract pretreatment on pharyngeal pumping rate in paraquat-exposed C. elegans?
• Does the antioxidant source change the day when worms first show a major drop in pumping rate?
• To what extent does antioxidant dose shift survival after oxidative stress in C. elegans?
• Which treatment, vitamin C or green tea extract, better preserves both lifespan and feeding after paraquat exposure?
• How does combining vitamin C with green tea extract change the survival curve compared with either antioxidant alone?

Basic Materials

• C. elegans starter kit with culture plates and bacterial food.
• USB microscope with stable stand.
• Stereo microscope or dissecting microscope.
• Petri dishes or nematode culture plates.
• Disposable transfer pipettes and glass dropper.
• Vitamin C powder or tablets, and food-grade green tea extract.
• Paraquat solution prepared under supervision.
• Notebook, timer, and labeled sample tubes.

Advanced Materials

• Compound microscope with phase contrast.
• Temperature-controlled incubator.
• Worm pick or platinum wire pick.
• Nematode growth medium plates with E. coli OP50.
• Analytical balance and calibrated pipettes.
• Fixed video capture setup with even illumination.
• Image analysis workstation for frame-by-frame scoring.

Software & Tools

• Fiji/ImageJ: Measures pharyngeal pumping from video frames and still images.
• Python: Cleans replicate data, plots survival curves, and runs basic statistics.
• R: Fits Kaplan-Meier survival curves and compares treatment groups.
• Google Sheets: Organizes counts, labels replicates, and makes quick graphs.

Experiment Steps

1. Define one stress dose, one control group, and one antioxidant comparison so your question stays narrow.
2. Choose the worm stage you will test and keep age matched across every group.
3. Plan how you will score both lifespan and pharyngeal pumping from the same animals.
4. Build a measurement workflow that keeps lighting, focus, and scoring rules the same in every session.
5. Decide on your plots and statistics before you start, so you can compare survival curves, average pumping, and dose response cleanly.
6. Set up a side-by-side comparison of single antioxidants and the combined treatment.

Common Pitfalls

• Counting body bends instead of pharyngeal pumps, which mixes movement with feeding and blurs the result.
• Using worms at different ages in different groups, which makes aging differences look like an antioxidant effect.
• Letting bacteria or debris crowd the mouth region, which hides the tiny pumping motion in microscope videos.
• Scoring worms as dead without a touch response check, which can overstate survival after paraquat stress.
• Changing focus or lighting between video sessions, which makes pumping counts drift from one day to the next.

What Makes This Competitive

A stronger project goes beyond a simple yes-or-no answer. It compares two antioxidants side by side, uses matched controls, and separates survival from feeding so you can see whether one readout changes before the other. You can raise the level again by testing a dose response and using full survival-curve analysis instead of only a final count. That kind of design looks like real toxicology work, not just a classroom demo.

Project Variations

• How does vitamin C compare with green tea extract on worms exposed to a different oxidant, such as hydrogen peroxide?
• What is the effect of antioxidant pretreatment on C. elegans locomotion speed after paraquat stress?
• Does a combined vitamin C and green tea extract treatment protect worms better than either treatment alone?

Learn More

• WormBook: Free chapters on C. elegans anatomy, life cycle, and methods, found by searching WormBook online.
• WormBase: Free database for C. elegans strains, genes, and phenotype notes, found by searching WormBase online.
• PubMed: Search review articles on C. elegans oxidative stress, paraquat, and antioxidants.
• NIH Office of Dietary Supplements Vitamin C Fact Sheet: Background on vitamin C biology and dietary roles, found on the NIH ODS site.
• PubChem: Look up paraquat, vitamin C, and green tea catechins for properties and safety notes.
• MIT OpenCourseWare: Search free cell biology or biochemistry lectures on reactive oxygen species and antioxidants.