Discipline: Ecology Environmental and Earth Sciences
Room: Exhibit Hall A
Danielle Tindall - Norfolk State University
Co-Author(s): Dr. Nazir Barekzi, Norfolk State University, Norfolk, VA
In order to determine the health of the Elizabeth River, the phage diversity was investigated along the shoreline of the Eastern Branch of the Elizabeth River. The purpose of this study was to isolate mycobacteriophage using the host Mycobacterium smegmatis mc²155. Preliminary studies using direct isolation from the soil did not produce any phage. Therefore, an enrichment protocol was used to increase the yield. In addition, the normal incubation time of 2 days was increased incrementally to determine if more phage could be isolated. Hypothesis If soil samples were enriched with Mycobacterium smegmatis beyond 2 days, then the number of plaques will increase proportionately with the longer incubation time. Methods and Materials Six soil samples were collected from the same location approximately 3-9 feet apart along the bank of the Elizabeth River in Norfolk, Virginia. The soil samples were enriched by adding growth media and the host bacterium to the soil, incubated for different days at room temperature (~25°C), and then filtered with a syringe and 0.22 um filter to purify and isolate phage from the environmental soil sample. An infection assay with an overlay was used to produce plaques. The plaques were counted and the data was used to determine the number of plaques isolated in each sample after incubation of two, four, seven, nine and eleven days. Surprisingly, plaques were only evident on days seven and nine, indicating that a longer incubation time is needed to isolate phage from the soil of the Elizabeth River bank. However, the number of plaques found on day nine was lower than the amount found on day seven, and there were zero plaques evident on day eleven. The plaques were of different sizes and turbidity indicating the presence of a diverse group of phage in this investigai ton. In conclusion, these results suggest that seven days is the optimal incubation time when using the enrichment protocol to produce the most plaques. However, increasing the length of incubation beyond 7 days did not necessarily increase yield. Furthermore, there were other factors that could have affected the amount of phage present such as where the soil samples were collected from and how close they were to the body of water where tidal flow could impact the presence of phage. Future studies will focus on (1) increasing the temperature of incubation to produce higher phage yields; (2) investigating the impact of seasonal change, tides and temperature on the diversity of phage; and (3) using electron microscopy to identify the structural morphology of each phage. Lastly, the phage genomes will be sequenced, annotated and analyzed to determine any significant differences in the genome architecture of these isolated phage. Reference Doss, J., Culbertson, K., Hahn, D., Camacho, J., & Barekzi, N. (2017). A Review of Phage Therapy against Bacterial Pathogens of Aquatic and Terrestrial Organisms. MDPI.
Funder Acknowledgement(s): This study was supported, in part, by a grant from NSF (HBCU-UP-RIA Grant 1900164) awarded to Dr. Nazir Barekzi, Assistant Professor, Norfolk State University, Norfolk, Virginia
Faculty Advisor: Dr. Nazir Barekzi, firstname.lastname@example.org
Role: I participated in the whole project from beginning to end. This project was part of a summer research project that I was selected for. I collected samples and recorded data as well as write reports and present my work.