Event Title

Determination of Host Range Variation Between Highly Related Members of a Novel Cluster of Rhodobacter Capsulatus Bacteriophages

Faculty Advisor

Richard Alvey

Graduation Year

2019

Location

Room E104, Center for Natural Sciences, Illinois Wesleyan University

Start Date

21-4-2018 11:00 AM

End Date

21-4-2018 12:00 PM

Description

Bacteriophages, viruses that infect bacteria, have been studied for more than a century, but recent advances in sequencing technologies allow for a renaissance in our understanding of the composition, function, and evolution of these remarkable biological entities. Studies in the 1970s on bacteriophages that infect the purple, nonsulfur, alphaproteobacterium Rhodobacter capsulatus revealed abundant and diverse populations. Their molecular composition and evolutionary relationships remained unclear, however, without genomic sequencing. Now there are more than 20 isolated R. capsulatus bacteriophages that have been isolated by IWU students, and based on DNA sequence similarities, these phages fall into four distinct clusters, groups of bacteriophages that share 50% of their genomic sequence. An additional three sequenced phages in the IWU collection remain unclustered as singletons. All together these phages reveal hundreds of uncharacterized genes. We present evidence that some of these uncharacterized genes play a role in host range expansion. Specifically, it was observed that although the RcC cluster phages RcDormio and RcOceanus exhibited a high degree sequence similarity, RcDormio is capable of infecting R. capsulatus host strains YW1 and B10 while RcOceanus is only capable of infecting YW1. Comparison of the genomes of these phages revealed several regions that are present in RcDormio, but absent from RcOceanus. To test the requirement of these genes for host-range expansion in this cluster, genetic recombination experiments were performed using both phage genomes and the R. capsulatus host. This methodology may lead to an increased understanding of the functions of a broad range of uncharacterized phage genes. Further, these novel R. capsulatus phages have served as a platform for the development of methods for genetic experimentation, and allowed for a greater understanding of their functioning and evolution.

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Apr 21st, 11:00 AM Apr 21st, 12:00 PM

Determination of Host Range Variation Between Highly Related Members of a Novel Cluster of Rhodobacter Capsulatus Bacteriophages

Room E104, Center for Natural Sciences, Illinois Wesleyan University

Bacteriophages, viruses that infect bacteria, have been studied for more than a century, but recent advances in sequencing technologies allow for a renaissance in our understanding of the composition, function, and evolution of these remarkable biological entities. Studies in the 1970s on bacteriophages that infect the purple, nonsulfur, alphaproteobacterium Rhodobacter capsulatus revealed abundant and diverse populations. Their molecular composition and evolutionary relationships remained unclear, however, without genomic sequencing. Now there are more than 20 isolated R. capsulatus bacteriophages that have been isolated by IWU students, and based on DNA sequence similarities, these phages fall into four distinct clusters, groups of bacteriophages that share 50% of their genomic sequence. An additional three sequenced phages in the IWU collection remain unclustered as singletons. All together these phages reveal hundreds of uncharacterized genes. We present evidence that some of these uncharacterized genes play a role in host range expansion. Specifically, it was observed that although the RcC cluster phages RcDormio and RcOceanus exhibited a high degree sequence similarity, RcDormio is capable of infecting R. capsulatus host strains YW1 and B10 while RcOceanus is only capable of infecting YW1. Comparison of the genomes of these phages revealed several regions that are present in RcDormio, but absent from RcOceanus. To test the requirement of these genes for host-range expansion in this cluster, genetic recombination experiments were performed using both phage genomes and the R. capsulatus host. This methodology may lead to an increased understanding of the functions of a broad range of uncharacterized phage genes. Further, these novel R. capsulatus phages have served as a platform for the development of methods for genetic experimentation, and allowed for a greater understanding of their functioning and evolution.