16.01.2018

Research projects

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Funding

My research is funded by the Jane and Aatos Erkko FoundationAcademy of Finland, and through the BONUS FLAVOPHAGE project.

The ecological and epidemiological conditions of fish farming environment may select for more virulent and competitive pathogen strains, in both short and long time scales. However, phages can efficiently be used to control F. columnare infections. The phage FCL-2 can reduce the transmission of columnaris disease in a rainbow trout population, delay the onset of disease and persist in the flow-through system for up to 48 hours. These results are encouraging for development of phage therapy.

Phages infecting F. columnare can be isolated fish farms. The host range of F. columnare phages is narrow and they do not infect other bacterial species. When co-cultured in the presence of phage, bacteria lose their virulence and motility.  The loss of these fundamental features by gaining phage resistance provides an interesting starting point for future studies in trade-offs between virulence and phage resistance.

Our recent study publisher in Nature Communications shows the molecular details of a long-term (2003-2014) phage–bacterium arms race in the environment. Bacteria (Flavobacterium columnare) were generally resistant to phages from the past and susceptible to phages isolated in years after bacterial isolation. Bacterial resistance selected for increased phage infectivity and host range, which was also associated with expansion of phage genome size. We identified two CRISPR loci in the bacterial host: a type II-C locus and a type VI-B locus. While maintaining a core set of conserved spacers, phage-matching spacers appeared in the variable ends of both loci over time. The spacers mostly target the terminal end of the phage genomes, which also exhibit the most variation across time, resulting in arms race-like changes in the protospacers of the coevolving phage population.

Our research on phage therapy is funded by a grant from Jane and Aatos Erkko FoundationKey project funding by Academy of Finland, and through the BONUS FLAVOPHAGE project.