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BIOL2018CALLAGHAN48892 BIOL

Identifying Cellular Proteins that Interact with Hepatitis C Virus Protein NS3/4A

Type: Undergraduate
Author(s): Kaitlyn Callaghan Biology
Advisor(s): Giridhar Akkaraju Biology

Hepatitis C Virus is estimated to infect 3% of the world’s population and is transmitted by contaminated blood. HCV can be asymptomatic or lead to cirrhosis of the liver, liver cancer or hepatocellular carcinoma. Understanding the virus life cycle and the viral proteins generated by HCV will help generate new mechanisms of inhibition of the virus. HCV produces 10 viral proteins when it infects hepatocytes that increase the reproduction ability of the virus. The anti-viral response of the body uses transcription factors such as ATF-2, NFKB, and IRF-3 that translocated into the nucleus and bind to the interferon gene that produces interferon to alert the body of a viral infection. HCV viral protein NS3/4A acts as protease to cleave the polycistronic strand of viral proteins made by HCV and is known to inhibit IRF-3 movement into the nucleus to inhibit the production of interferon. HCV viral protein NS5A is known to inhibit the movement of transcription factor NFKB into the nucleus, thus inhibiting the anti-viral response. We are interested to see if NS3/4A inhibits the anti-viral response by blocking the movement of both transcription factors IRF-3 and NFKB into the nucleus.

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BIOL2018FREDIANI25359 BIOL

Effects of social isolation on LPS-induced hippocampal amyloid-beta expression and cognitive dysfunction in C57BL6/J male and female mice

Type: Undergraduate
Author(s): Gabrielle Frediani Biology Rachel Donaldson Biology Micah Eimerbrink Psychology Christopher Hagen Biology Julia Peterman Psychology Jordon White Psychology
Advisor(s): Michael Chumley Biology Gary Boehm Psychology Meredith Curtis Biology

Psychological stress afflicts a considerable portion of the world’s population, and is linked, as both a risk factor and potential contributor, to dementia-related brain dysfunction in diseases such as Alzheimer’s disease (AD). The brain dysfunction in AD is marked by an increase in Amyloid-beta, the protein responsible for plaque deposition in the brain. The present study aimed to explore alterations in the production of amyloid-beta in response to stress and inflammation. Specifically, we were interested in social isolation stress- and inflammation-induced differences in cognition and amyloid-beta production in male and female mice. Mice were subjected to acute social isolation (6 days) and chronic isolation (28 days) or control group housing. Results revealed that exposure to both acute and social isolation can lead to an exacerbated inflammatory response to lipopolysaccharide (LPS). Subsequently, we examined if the stressors altered amyloid-beta production following the same inflammatory stimulus. Animals received LPS or saline injections once per day for seven consecutive days after the completion of either stress protocol or group housing. The contextual fear conditioning paradigm (CFC) was utilized to assess cognition. Brain tissue extractions were performed to quantify amyloid-beta protein levels. It is hypothesized that isolated animals will demonstrate cognitive deficits in CFC as well as increased brain amyloid-beta following LPS injections.

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BIOL2018HUYNH84096 BIOL

Determine Phytoene Desaturase Gene Copy Number in Hydrilla verticillata

Type: Undergraduate
Author(s): Tu Huynh Biology
Advisor(s): Dean Williams Biology Matt Hale Biology

Hydrilla verticillata is an invasive aquatic weed in the United States (U.S.) that has recently
developed resistance to the herbicide fluridone. In this study, we utilized genome walking and
quantitative real-time PCR to investigate the phytoene desaturase (PDS) gene copy number of
hydrilla samples with different ploidy levels. We asked 1) if copy number simply corresponds to the
ploidy level, and 2) if there is increased PDS copy number in resistant populations due to gene
duplication. Using qPCR and microsatellite loci to compare PDS copy number between diploid,
triploid and tetraploid samples, we found that diploid hydrilla from Africa showed higher PDS copy
number than triploid populations from the U.S. The results also indicated that there was no
significant difference in PDS gene copy numbers between the fluridone-resistant and -susceptible
triploid populations. Our study suggests that PDS amplification may not be a mechanism
responsible for fluridone resistance in hydrilla.

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BIOL2018KHAN19280 BIOL

Methylmercury Contamination in Terrestrial Spiders along the Trinity River

Type: Undergraduate
Author(s): Amal Khan Biology Garrett Wallace Biology
Advisor(s): Matthew Chumchal Biology Ray Drenner Biology

Methylmercury (MeHg) is a toxic environmental contaminant found in all waterbodies on Earth. Aquatic emergent insects, such as mosquitoes and midges, can transfer MeHg from waterbodies to terrestrial ecosystems. Terrestrial shoreline spiders consume aquatic emergent insects and become contaminated with MeHg. Methylmercury-contaminated spiders can pose a risk to songbirds that consume terrestrial spiders. Because shoreline spiders have MeHg concentrations that reflect MeHg contamination of nearby aquatic ecosystems and are an important source of MeHg to songbirds, they have been proposed as a biosentinel species that can be used to estimate MeHg contamination of waterbodies. In this study, I used long-jawed orb weavers (Tetragnatha sp.) as a biosentinel species to examine MeHg contamination along the Clear Fork and the West Fork of the Trinity River, Fort Worth, Texas. The objectives of this study were to: 1) evaluate MeHg contamination in long-jawed orb weavers from two forks of the Trinity River, and 2) determine if the concentrations of MeHg in the spiders pose a risk to songbirds that feed on spiders. I collected 101 and 105 spiders along the Clear Fork and the West Fork, respectively. I used a Direct Mercury Analyzer to determine the total Hg concentration of the long-jawed orb weavers. Because MeHg is the primary species of mercury in spider tissues, I used total Hg as a proxy for MeHg. All spiders were contaminated with MeHg, with spiders along the Clear Fork having significantly higher MeHg concentrations than spiders along the West Fork. Methylmercury in spiders increased with spider size along the Clear Fork. Concentrations of MeHg in spiders along the Clear Fork and the West Fork were high enough to pose a risk to the physiology of nestling songbirds that feed on spiders.

(Presentation is private)

BIOL2018MITCHELL9635 BIOL

Seasonality of Insect-Mediated Methyl Mercury from Emerging Odonates

Type: Undergraduate
Author(s): Will Mitchell Biology
Advisor(s): Matt Chumchal Biology Ray Drenner Biology

Methylmercury (MeHg) is an aquatic contaminant that can be transferred to terrestrial predators by emergent aquatic insects such as odonates (damselflies and dragonflies). We observed the effects of time on odonate-mediated MeHg flux (calculated as emergent odonate biomass MeHg concentration) in 20 experimental ponds and the potential risk to nestling red-winged blackbirds (Agelaius phoeniceus) posed by consuming MeHg-contaminated odonates. Emergent odonates were collected weekly from ponds containing four emergent traps per pond over an 9-mo period (February–October 2017). The MeHg flux from damselflies, aeshnid dragonflies, and libellulid dragonflies began in March and peaked in May, June, and July, respectively, and then declined throughout the rest of the summer. Nesting of red-winged blackbirds overlapped with peak odonate emergence and odonate-mediated MeHg flux. Because their diet can be dominated by damselflies and dragonflies, we tested the hypothesis that MeHg-contaminated odonates may pose a health risk to nestling red-winged blackbirds. Concentrations of MeHg in odonates exceeded wildlife values (the minimum odonate MeHg concentrations causing physiologically significant doses in consumers) for nestlings, suggesting that MeHg-contaminated odonates can pose a health risk to nestling red-winged blackbird.

(Presentation is private)