Coliphage Discovery and Genome Characterization

ISEF Category: Microbiology

Subcategory: Virology  ·  Difficulty: Advanced  ·  Setup: University Lab  ·  Time: Full Year

The Hook

A single spoonful of soil can hold viruses that hunt bacteria. That means your backyard can become a discovery site. If you find a new phage, you are not just counting microbes, you are mapping a tiny predator-prey system that could matter for biology and biotech.

What Is It?

Coliphages are viruses that infect E. coli and related bacteria. Think of them like tiny lock-and-key predators. A phage can only infect cells that have the right surface features and internal machinery, so each isolate can have a different host range, which means the set of bacteria it can attack.

This project asks you to find phages in soil or wastewater, grow them on a safe E. coli K-12 host, and then compare how they behave on other BSL-1 Enterobacteriaceae. You can also connect what you see in the lab to what the phage looks like under an electron microscope and what its genome suggests about its life cycle, genes, and family group. That gives you three views of the same organism, phenotype, morphology, and DNA.

Why This Is a Good Topic

This is a strong science fair topic because it starts with a real unknown. You can search local samples, isolate candidates, and compare them in ways that produce clear data. The project also connects to public health, wastewater monitoring, and phage biology, so your work has a real-world angle. You can learn isolation, plaque analysis, host-range testing, microscopy interpretation, and basic genome annotation without needing a medical or BSL-2 lab.

Research Questions

• How does sample source, soil versus wastewater, affect the diversity of coliphages you can isolate??
• What is the effect of host strain choice on plaque size and plaque clarity for isolated phages??
• Does host range across BSL-1 Enterobacteriaceae predict phage morphology class from electron microscopy??
• To what extent do isolated phages from different sites differ in genome size and gene content??
• Which environmental sample type yields phages with the broadest host range across safe bacterial strains??
• How does storage time before enrichment affect the number of viable phage isolates recovered??

Basic Materials

• Sterile sample collection tubes or bags.
• E. coli K-12 starter culture.
• BSL-1 Enterobacteriaceae panel approved by your mentor or school lab.
• Petri dishes and agar plates.
• Sterile pipettes and tips.
• Incubator approved for microbial work.
• Micropipette set.
• Tube racks.
• Parafilm or plate sealing film.
• Permanent marker for labeling.
• Digital camera or smartphone for plate images.
• PPE required by the lab, including gloves, a lab coat, and eye protection.

Advanced Materials

• Access to a university or partner lab with phage handling approval.
• Electron microscopy access through a partner facility.
• Nanopore sequencing access coordinated by a mentor.
• Centrifuge suitable for microbial sample prep.
• Spectrophotometer or plate reader for bacterial growth checks.
• Gel electrophoresis setup for nucleic acid quality checks.
• PCR setup if the mentor includes confirmation assays.
• Bioinformatics workstation or cloud-based analysis access.
• Freezer storage for isolate archives.
• Sterile filtration setup for sample clarification.

Software & Tools

• SnapGene Viewer: Helps you inspect annotated phage genomes and read gene maps without paying for the full software.
• Geneious Prime trial or equivalent institutional access: Lets you organize sequencing reads and review draft assemblies if your lab provides access.
• Flye: Assembles nanopore reads into draft phage genomes.
• NanoPlot: Summarizes read quality and length for nanopore data.
• ImageJ: Measures plaque diameter and compares electron microscopy images or plate photos.

Experiment Steps

1. Define your discovery question and choose the environmental samples you will compare.
2. Decide your host panel, then set up a safe, mentor-approved plan for screening phages against each strain.
3. Build a consistent way to score plaque traits, host range, and sample yield so your data stay comparable.
4. Plan how you will confirm that each isolate is unique, not just the same phage recovered twice.
5. Coordinate the microscopy and sequencing steps so the morphology, genome, and host-range data line up for each isolate.
6. Choose the analysis you will use to compare isolates, such as diversity, clustering, or correlations between traits.

Common Pitfalls

• Using uneven soil or wastewater sampling methods, which makes one site look richer in phages just because the sample was handled differently.
• Confusing bacterial contamination with true phage plaques, which can lead you to count the wrong signal as a positive isolate.
• Testing host range on different days with inconsistent lawns, which changes plaque calls and weakens comparisons.
• Treating repeated plaques from the same enrichment as new isolates, which inflates your diversity claim.
• Assembling a draft genome before checking read quality and coverage, which can create a misleading phage sequence.

What Makes This Competitive

A stronger project goes past simple isolation. You can compare environmental source, host range breadth, plaque morphology, microscopy class, and genome features in one dataset. The best versions also include careful isolate tracking, clean controls, and a clear statistical plan for comparing phage groups. If you find a pattern that links genome features to host range or sample source, that makes the project much deeper.

Project Variations

• Compare phages from urban wastewater versus garden soil to see which source gives the broadest BSL-1 host range.
• Focus on one phage family and test whether plaque morphology matches genome-based cluster assignment.
• Track how host range changes across multiple safe Enterobacteriaceae strains and use that to predict possible receptor preferences.

Learn More

• NIH and NCBI Virus: Search for review articles and genome records on bacteriophages and phage genomics.
• PubMed: Search for review papers on coliphage isolation, host range, and wastewater phage ecology.
• NCBI Genome and Sequence Read Archive: Find phage genome records and example nanopore datasets for analysis practice.
• ASM Journals: Read peer-reviewed phage biology and microbiology articles, many with accessible abstracts and some open full text.
• MIT OpenCourseWare Biology materials: Review free background on molecular biology, viruses, and genome analysis concepts.