Microbacteriophage Hasitha is a virus that infects Microbacterium foliorum, a bacterium associated with grasses that was first discovered in Germany. Hasitha was isolated from an enriched compost sample and is of particular interest due to its unusual growth pattern. Most bacteriophages require actively growing host cells to produce new phage progeny. However, Hasitha can infect and kill stationary (non-replicating) bacterial cells. We discovered this unusual characteristic through a fortuitous observation of infected lawns that were allowed to incubate in the lab workspace for approximately one month. During this time, a noticeable “halo” grew around the initial site of infection and consumed most of the lawn. Here we report the genomic sequence of Hasitha and its ultrastructural features. We also report the results of experiments to determine the mechanism for the expanding halos of growth. Our results suggest that Hasitha phage particles diffuse outward from the initial site of infection and continue to infect and lyse surrounding stationary host cells. We also found through analysis of bacteriophages closely related to Hasitha that the halos are genetic in nature, with genome annotation suggesting a few gene products of unknown function to have possibly hydrolytic properties. Lastly, thin sectioning determined that the bacterial hosts found in the developed halo are no longer in stationary phase. These findings elucidate previously unknown factors in phage infection of stationary phase bacteria and provide data to be expanded upon in future studies.
Advisor(s) or Committee Chair
Rodney King, Ph.D.
Bioinformatics | Biology | Microbiology | Virology
Brown, Gillian, "The Isolation and Characterization of Bacteriophage Hasitha" (2022). Mahurin Honors College Capstone Experience/Thesis Projects. Paper 982.