Date of Award
Master of Science (MS)
Bioinformatics & Computational Biology
Once considered sterile in the absence of an infection, the female urinary tract is home to a diverse community (microbiota) of bacterial species and bacteriophage (phage), viruses that infect bacteria A dominant member of the female urinary microbiota is the bacterial genus Lactobacillus. Several Lactobacillus species are even associated with urinary health. Phage infectious of bacteria in the urinary tract tend to replicate through one of two life cycles: the lytic (active) life cycle or the lysogenic (dormant) life cycle. Temperate phage can switch from the lysogenic life cycle to the lytic life cycle in the presence of an environmental cue. This process is called induction. Within the urinary tract, Lactobacillus species naturally produce several of the inducing agents used in the lab; they release lactic acid, reducing the pH of their environment, and hydrogen peroxide as part of the glycolytic pathway. This observation motivated the investigation into how Lactobacillus metabolites induce phage in other urinary bacteria species. Eight communities, each containing either a Lactobacillus jensenii or Lactobacillus mulieris strain and at least two other community members, were selected for analysis. The genomes of all community members were sequenced and screened for the presence of phage. The pH and hydrogen peroxide outputs were measured for each of the L. jensenii and L. mulieris isolates. Other taxa in the community were grown in media adjusted to Lactobacillus-relevant pH levels based up on the Lactobacillus strain in their community. These cultures were screened for the presence of induced phage. Finally, community members were grown with varying concentrations of their community's Lactobacillus strain's spent media. These cultures were sequenced, and the sequences were screened for the presence of induced phage. 106 individual phage were induced during this process. These results suggest that Lactobacillus is inducing phages in other community members in the urinary tract. Thus, the beneficial effects of Lactobacilli in the urinary tract and/or the dominance of Lactobacillus in the female urinary tract may be a result of induction and lysis of other bacterial taxa.
Miller-Ensminger, Taylor, "Lactobacillus Metabolite-Mediated Induction of Bacteriophage" (2021). Master's Theses. 4393.
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