Investigation of Codependent Strain Characteristics in Polyclonal Vibrio fischeri Infections

Mutualisms are the relationships between two species where both participants benefit and are prevalent in nature. Many mutualisms take place between an animal host and an internal microbe, such as bacteria. These internal bacterial populations can consist of multiple strains of species and the make-up of these populations can impact host health and disease (Bielaszewska, 2011). The interactions between bacterial strains within a mutualism are understudied because many model systems are burdened by confounding variables associated with the presence of multiple species. The symbiosis between the bioluminescent marine bacterium Vibrio fischeri and the Hawaiian bobtail squid, Euprymna scolopes, provides a model to study these mutualistic interactions because V. fischeri is the only species of bacteria to colonize the squid host in a specialized organ. In this study, we isolated and characterized two strains of V. fischeri from a wild-caught squid, CHS319 and ECT001. These strains were analyzed for their ability to swim through media, bioluminesce in vitro, produce quorum sensing molecules, and colonize juvenile animals. It was determined that one of the natural isolates requires the presence of another natural isolate in the inoculum in order to colonize juvenile squid. We also developed a data set of co-colonization of the well characterized type strain, ES114, by which we can compare other co-colonizations of natural isolates. This data set can be used as a technical control in future co-colonizations and as a statistical tool to uncover other patterns pertaining to colonization. Overall, this study has uncovered preliminary data that provides a basis for future studies on strain interactions. Future experiments on the relationship between CHS and ECT will reveal novel mechanisms by which bacterial strains may interact and result in polyclonal infections within a host.



Work Title Investigation of Codependent Strain Characteristics in Polyclonal Vibrio fischeri Infections
Penn State
  1. Caroline Helen Steingard
  1. symbiosis, mutualism, bacteria, strain, interaction, quorum sensing
License All rights reserved
Work Type Article
Deposited March 19, 2018




This resource is currently not in any collection.

Work History

Version 1

  • Created
  • Added Caroline_Steingard_Thesis_Final.pdf
  • Added Creator Caroline Helen Steingard
  • Published