# Theoretical and Experimental Studies of the Population and Evolutionary Dynamics of Bacteria and Bacteriophage.

> **NIH NIH R35** · EMORY UNIVERSITY · 2024 · $390,000

## Abstract

ABSTRACT
The viruses of bacteria and archaea, phage, are touted to be the most abundant organisms on Earth, and a
great deal is known about their molecular biology, structure, and mechanisms of replication. Nevertheless
there remain fundamental unanswered or incompletely answered questions about the population biology,
ecological role, and evolution of these viruses. In this investigation we will address and provide answers to
three of these fundamental questions: 1- What are the ecological, genetic and evolutionary conditions for
lytic (virulent) phage to be maintained in and regulate the densities of bacterial populations? 2- Under
what conditions will selection favor a temperate rather than a purely lytic mode of phage replication and
transmission? 3- Under what conditions will selection by lytic and temperate phage favor the evolution
and maintenance of CRISPR-Cas mediated adaptive immunity, rather than envelope or other constitutive
resistance mechanisms? To address these questions, we will use mathematical and computer simulation
models, the properties of which will be analyzed numerically with parameters estimated in the
experimental systems that will be employed for population dynamic and evolutionary experiments. We
will test the predictions (hypotheses) generated from our analysis of these models in populations of
bacteria and phage maintained in liquid, surface, and semisolid culture. Based on the results of these
experiments, we will modify our models to make them more realistic. The experiments will be done with
Escherichia coli, Pseudomonas aeruginosa, Pseudomonas syringae, and Staphylococcus aureus and their
lytic and/or temperate phage. In addition to their importance to academic ecology, population and
evolutionary biology, the results of this basic science study may well have practical utility. This
investigation will provide an empirically supported theory that could be used to facilitate the design and
evaluation of programs to use phage for the treatment of bacterial infections in humans and domestic
animals, and to control outbreaks of pathogenic bacteria in crops.
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## Key facts

- **NIH application ID:** 10764809
- **Project number:** 5R35GM136407-05
- **Recipient organization:** EMORY UNIVERSITY
- **Principal Investigator:** Bruce Richard Levin
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $390,000
- **Award type:** 5
- **Project period:** 2020-04-01 → 2026-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10764809

## Citation

> US National Institutes of Health, RePORTER application 10764809, Theoretical and Experimental Studies of the Population and Evolutionary Dynamics of Bacteria and Bacteriophage. (5R35GM136407-05). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10764809. Licensed CC0.

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