Perpetue Backer (Summer 2009)

Field of research:

Lab: Noel Goddard

School: Manhattan Hunter Science High School

Year: 10th/11th Grade

Research Abstract:

Population Dynamics of Host/ Viral Interactions

    This summer I completed an internship at Dr. Goddard’s lab. While I learned and accomplished many things, I worked on a specific project with other members of the Goddard Lab. The goal of the project, called Population Dynamics of Host/Viral interactions is to understand the interaction between a host and its virus which is bacteria.
    Escherichia coli and bacteria phage M13 were used as a model system to study Host/Virus population dynamics. M13 uniquely infects E.coli that has a pilus for conjugation. The pilus is determined by the conjugative F plasmid, and can be transmitted within or between species of bacteria through a process called conjugation. We developed a counting assay based on quantitative PCR to assess the numbers of phage, cells, and F plasmids during different stages of the population’s growth. Several historical natural isolates of E.coli were studied as well as a commercial F+ strain, JM109, containing a selection marker for the plasmid [F’]. Samples of the population were collected of the cells counted through optical density measurements. Phage titers of the inoculation method were also performed. By varying the growth conditions, infection timing, and stringency of F plasmid selection, we attempt to elucidate an understanding of the role of selection pressure versus F plasmid maintenance.

Personal Comment:

Working in Dr. Goddard's Lab was an amazing experience. I learned a lot and I Hope to keep in contact with her and other lab members.

Other Accomplishment: