Undergraduate Research Day 2021

Permanent URI for this collectionhttp://hdl.handle.net/1903/27016

With students involved in so many research opportunities, Undergraduate Research Day provides the perfect opportunity for them to share their work with the campus community. Held each April, Undergraduate Research Day showcases current research, scholarship, and artistic endeavors.

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Author: search.filters.author.Lee, Harrison

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    Investigating Arginine Biosynthesis in Viral Replication
    (2020-11) Lee, Harrison; Griffin, Ryleigh; Stecklein, Sabrina; Chaudry, Daniel; O'Hara, Jessica
    When a virus infects a cell, it must hijack that host cell’s inner machinery, normally used to manufacture necessary molecules for the host cell, and divert that machinery to producing new viruses. Previous research has indicated that arginine, an amino acid, plays an important role in viral infection. We investigated the role arginine plays in infection in two ways. First, we compared how well bacteriophage, a type of bacteria-infecting virus, replicated in normal (parent) E. coli and genetically modified E. coli that could not produce their own arginine. These genetically modified E. coli are called a knock-out strain because the gene for a particular protein, in this case an enzyme involved in producing arginine, is removed. The gene in question is called argH and thus the knock-out strain is named ΔargH. Here we found that when arginine was available from outside the cell, there was no significant difference between bacteriophage replication in the two E. coli strains. Second, we observed how the levels of certain small molecules (metabolites), including arginine, inside a human cell changed after it was infected with the Human Cytomegalovirus (HCMV). We found that HCMV infected cells had altered levels of metabolites from throughout the arginine biosynthesis pathway, including increased levels of arginine.
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    Characterizing a Chimera: Comparative Analysis of Pal Endolysin and its Homologs
    (2021-04) Griffin, Ryleigh; Lee, Harrison; O'Hara, Jessica; Nelson, Daniel
    Once a virus infects a cell and produces more virus particles (virions), it must find a way to release those virions so they can infect more cells. Bacteriophage, or viruses that infect bacteria, accomplish this goal by producing endolysins, proteins that cause bacterial cells to lyse by breaking down their cell walls. Many endolysins have a modular structure consisting of an enzymatically active domain (EAD), which catalytically breaks bonds in peptidoglycan, the main component of bacterial cell walls, and a cell wall binding domain (CBD), which attaches the endolysin to the cell wall and determines host specificity. By combining EADs and CBDs from different endolysins, researchers can produce new “chimeric” endolysins in order to kill disease-causing bacteria in a targeted fashion, which can be more effective than the original enzymes. Chimeric endolysins can also form naturally. Bacteriophage Dp-1, which infects Streptococcus pneumoniae bacteria, produces a chimeric endolysin called Pal. Pal’s CBD has the ability to bind to choline and is very similar to a portion of the LytA enzyme produced by S. pneumoniae. Pal’s EAD breaks down amide bonds in peptidoglycan and is very similar to a portion of the endolysin produced by a Bacteriophage BK5-T, which infects Lactococcus lactis bacteria. In our research, we used bioinformatics techniques to find other proteins that share homology with Pal and to investigate the evolutionary relationships between these proteins. We hope that a better understanding of this natural chimeric endolysin could be useful to researchers attempting to engineer new ones.