Faculty Mentor(s)

Dr. Joseph Stukey, Biology

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Twenty new mycobacteriophages were isolated from soil samples collected around the state of Michigan and other parts of the United States. All phages were capable of infecting Mycobacterium smegmatis and were isolated through either enrichment or direct plating at 32℃. A variety of plaque morphologies were produced based on size, shape, and clarity; both lytic and temperate phages are represented in this collection. The mycobacteriophage, Bromden, was chosen as one of two phages for complete genome sequencing and comparative genomic analyses. The predominant plaque produced by Bromden after 48 hours at 32℃ is 0.5 mm in diameter, circular, and clear. The genome of Bromden is 70.2 Kb, 58.2% GC, and contains 118 genes. Bromden’s complete genome sequence indicates a relationship to mycobacteriophages of cluster L, and strongest similarity to mycobacteriophage DyoEdafos of subcluster L4, which is the only other member of the L4 subcluster of mycobacteriophages. The two genomes align at only 85% identity over 87% of the shorter Bromden, with the largest difference being an 8.5 kb section found in DyoEdafos but missing in Bromden. This accounts for the difference in their gene numbers, as DyoEdafos has 33 more genes than Bromden. Auto-annotation indicated there are 12 possible tRNA genes in Bromden. The GC content of Bromden (58.2%) is low compared to most other clusters of mycobacteriophages as well as their common host, M. smegmatis (67.4%). The other clusters with relatively low GC content also have few members, suggesting that these phages may more readily infect other bacterial hosts with lower GC content. A detailed analysis of the complete genome sequences and comparison with sequenced mycobacteriophages is the subject of the second semester of the yearlong course and is presented.


This research was supported by the Hope College Department of Biology.

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