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BIOL2019SKALLEY13801 BIOL

Developing a worm model to investigate breast cancer

Type: Undergraduate
Author(s): Courtney Skalley Biology Rachel Klevit Biology Sam Witus Biology
Advisor(s): Mikaela Stewart Biology
Location: Session: 1; Basement; Table Number: 4

presentation location

In many patients with breast cancer, a mutation in their BRCA1 gene disrupts BRCA1 protein’s function as a tumor suppressor. One mechanism through which BRCA1 prevents cancer is by acting as an enzyme to attach a signaling protein called ubiquitin to a H2A, a DNA packaging protein. This attachment inhibits gene expression of DNA damaging proteins. Here, we determine whether enzymatic activity of BRCA1 towards H2A is a conserved feature in C. elegans, a microscopic worm used as a model organism.

To measure conservation, we used mutagenesis to introduce mutations into C. elegans’ BRCA1 at a region homologous to the known human H2A binding site. Similar to mutations at this site in human BRCA1, our results showed a decrease in enzymatic activity when mutations were present. This indicates that C. elegans BRCA1 and human BRCA1 use similar mechanisms of attachment to H2A. To develop tools to study this reaction in C. elegans, we need to understand the position on H2A to which ubiquitin is attached. To accomplish this, we generated C. elegans H2A using cloning to eventually determine the specific location of ubiquitin attachment.

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BIOL2019SMITH53164 BIOL

The Effects of Insulin Crystallization Growth in Microgravity

Type: Undergraduate
Author(s): Laura Smith Biology John Balian Biology Alexander Ferguson Biology
Advisor(s): Magnus Rittby Physics & Astronomy
Location: Session: 2; 2nd Floor; Table Number: 3

presentation location

Our experiment is about diabetes and Human and synthetic insulin crystallization in a microgravity environment. This experiment is designed to help us find out if there is a way to prevent crystallization of insulin, especially if we understand how it happens in microgravity. When insulin crystallizes, the bacteria that usually makes it viable stops working. This would cause it to be ineffective for patients in dire need of this medication. To complete this experiment we would like to send three different varieties of insulin in a type 3 mini lab FME (Fluids Mixture Enclosure) to the International Space Station (ISS), kept in ambient temperatures, to see if it crystallization occurs within a certain amount of time. We will keep the experiment refrigerated at or below 40℉ during transportation to the ISS and again after arrival back to our lab to prevent crystallization occurring outside of the experiment. Refrigeration slows the crystallization growth and this is how it is stored on Earth. Keeping our experiment refrigerated during transportation is an important step because the insulin crystallization growth should only be measured while in microgravity. It is also important to note that crystallization of insulin is slow so change in crystal growth will not be evident if out of refrigeration for short periods of time. We would like to keep our insulin types out of refrigeration for a period of six weeks minimum. While testing insulin crystallization in microgravity, we will be conducting the same experiment on Earth as our control. If we can understand more about synthetic insulin, maybe one day diabetic men and women can follow their passion of being astronauts and humans with this disease will have the opportunity to go to microgravity environments for extended periods of time.

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BIOL2019TAETZ44707 BIOL

The Effects of Hepatitis C Virus NS5A Protein on Antiviral Gene Expression

Type: Undergraduate
Author(s): Sarah Taetz Biology
Advisor(s): Giridhar Akkaraju Biology
Location: Session: 1; 2nd Floor; Table Number: 7

presentation location

Hepatitis C virus currently infects around 130-170 million people. HCV, a member of the Flaviviridae family, causes chronic liver inflammation which can lead to liver cirrhosis or hepatocellular carcinoma. One of the nonstructural proteins of HCV, NS5A, is known to diminish the host innate immune response via inhibition of antiviral gene expression. NS5A blocks NFkB from entering the nucleus, decreasing transcription of IFN-B. Specifically, NS5A 10A, a mutant form of the protein, is known to greatly diminish the activity of the IFN B promoter. Our goal is to determine how WT NS5A and another mutant, NS5A H27, affect this pathway as well. We did this by transfecting HEK 293 cells with the NS5A mutant of interest, infecting the cells with Sendai virus, and subsequently measuring the activity of the IFN B promoter using a luciferase assay. In addition, NS5A contains three domains: I, II, and III. We are interested in determining which domain of NS5A is particularly important for blocking antiviral gene expression. We designed primers to created truncations of the protein containing the individual domains via PCR.

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BIOL2019THALHUBER31251 BIOL

Methyl Mercury Contamination and Diet of Nestling Red-winged Blackbirds

Type: Graduate
Author(s): Thomas Thalhuber Biology Matthew Chumchal Biology Ray Drenner Biology William Zudock Biology
Advisor(s): Matthew Chumchal Biology Ray Drenner Biology
Location: Session: 2; 2nd Floor; Table Number: 7

presentation location

Red-winged blackbirds (Agelaius phoeniceus) are found throughout North America, often nesting in cattails in ponds and wetlands. Diet studies have revealed that adults can feed their nestlings both emergent aquatic insects like odonates and terrestrial insects like lepidopteran larvae. Because emergent aquatic insects can be contaminated with high amounts of methyl mercury (MeHg), it has been hypothesized that nestlings fed high amount of odonates would be contaminated with levels of MeHg that are hazardous to their health. There have been no of studies of MeHg contamination of nestling Red-winged blackbirds and their diet. The objective of our study was to measure the concentration of MeHg in blood of nestling Red-winged blackbird and to estimate the proportion of emergent aquatic insects and terrestrial insects in their diet. We conducted a study of Red-winged blackbird nestlings at 20 ponds at the Eagle Mountain Fish Hatchery, Fort Worth, Texas. The ponds are contaminated with Hg from the atmosphere. Previous studies at the Hatchery have demonstrated that emergent aquatic insects such as odonates have high concentrations of MeHg while terrestrial insects on the pond shorelines have low concentrations of MeHg. Red-winged blackbirds nested in cattails in the ponds from April 9 to July 30 2017. We collected 424 blood samples from 243 nestlings from 88 nests (1-2 samples from 1-4 nestlings per nest). We analyzed the blood for MeHg, and analyzed 202 of the blood samples (1-2 blood samples from 1 per nest) for nitrogen stable isotopes. Methyl mercury was detected in nestling blood suggesting that Red-winged blackbird nestlings were fed emergent aquatic insects. However, concentrations of MeHg in nestling blood were low (mean of 0.020 ug/g ww) and below the risk threshold. Methyl mercury concentrations and nitrogen stable isotope ratios for Red-winged blackbird nestlings suggest that terrestrial insects composed a high proportion of their diets. Our study suggests that Red-winged blackbird nestlings may not be at risk of MeHg contamination when terrestrial organisms dominate their diet.

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BIOL2019TRAN15907 BIOL

Uncovering the effects of thyroid disruptors on immune function of fathead minnows

Type: Undergraduate
Author(s): Nghi Tran Biology Marlo Jeffries Biology
Advisor(s): Marlo Jeffries Biology
Location: Session: 2; 3rd Floor; Table Number: 10

presentation location

Previous studies showed that exposures to thyroid inhibitors during early stages of development lead to long-lasting alterations in disease resistance. Therefore, the goal of this project was to assess the effects of early life stages thyroid disruption on the maturation and function of immune cells using propylthiouracil (PTU)-exposed fathead minnow as a model system. The specific objectives of this study were to evaluate the impacts of early life stage PTU-exposure on 1) neutrophil migration and 2) transcriptomic markers of lymphoid and myeloid cell development. These objectives were accomplished by exposing fathead minnow embryos to 35 mg/L and 70 mg/L PTU for 10 days, while evaluating neutrophils migration with a tail nicking assay and assessing immune cell development by measuring transcriptomic markers of maturation at 10 days post fertilization (dpf). There were no differences in transcriptomic markers for lymphoid cell development between PTU and control groups. However, PTU-exposed larvae showed a decreased amount of neutrophils at wound site as well as decreased v-ymb expression compared to those of the control at days 7 and 10, indicating that early life stage thyroid disruption interfered with the normal development and subsequently reduced immune response in these organisms.

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BIOL2019TRAN59888 BIOL

A Pharmacogenomics Retrospective Study on the CYP Gene and its Variants for the Efficacy of Various Drugs across Different Races

Type: Undergraduate
Author(s): Nga Tran Biology
Advisor(s): Dennis Cheek Biology
Location: Session: 2; 3rd Floor; Table Number: 1

presentation location

Purpose: The objective of this retrospective study was to identify genetic variants of gene encoding a major drug-metabolizing enzyme among two different races – African American and Caucasian – based on pharmacogenomics testing and interpretive report (GeneSight). The study might shed lights for the application of precision prescribing in the clinical settings in the near future.
Methods: A retrospective study of de-identified interpretive reports from GeneSight of sixteen individuals (n = 16) at the Mental health Mental Retardation (MHMR) of Tarrant County. There are five reports of male and eleven reports of female in this study, of which six are African American and ten are Caucasians. The study was divided into two groups based on their races. Percentage of different alleles within variants of the CYP gene family were determined. Based on genetic components of patients, drug recommendations were made by AsureRx Healh, Inc.
Hypotheses: CYP2 is known to be highly polymorphic in the scientific literature. It is hypothesized that genetic variants will be observed in the CYP2 gene.

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BIOL2019TRULY25617 BIOL

Inducing Oxidative Stress Using Biotin Receptor Targeted Organometallic Compounds on Cancer Cells

Type: Undergraduate
Author(s): Tate Truly Biology
Advisor(s): Giridhar Akkaraju Biology Kayla Green Chemistry & Biochemistry
Location: Session: 2; 2nd Floor; Table Number: 5

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Cancer is one of the leading causes of death in the United States and is predicted to directly affect 38% of the population over the course of their life. Cancer is categorized as a collection of diseases primarily characterized by aberrant cellular proliferation. Many current cancer therapies, such as chemotherapy, do not differentiate between cancer cells and normal cells resulting in a variety of negative side effects. In an attempt to minimize these side effects, there has been a huge impetus to develop targeted therapies, which exploit cancer-specific molecules to exhibit selective toxicity towards cancer cells. For example, the monoclonal antibody Trastuzumab (Herceptin) targets the Human Epidermal Growth Factor Receptor 2 (HER2) that is overexpressed in some breast cancer cells. Another cancer-specific molecule overexpressed in some breast cancers, as well as cervical cancers, is the receptor for biotin. Biotin, more commonly known as Vitamin B7, functions intracellularly as an important coenzyme for several carboxylase enzymes involved in fatty acid synthesis, amino acid metabolism and gluconeogenesis. Thus, by overexpressing the biotin receptor some cancers increase their overall absorption of biotin resulting in a higher metabolic and proliferation rate. Furthermore, the high metabolic rate in cancer leads these cells to have increased to damage by reactive oxygen species (ROS) which can trigger apoptosis at high intracellular levels. Therefore, our project is exploring this overexpression of the biotin receptor as a potential avenue for targeted therapy against certain breast cancers. Ferrocene is an organometallic compound with an iron-center that has been shown to generate ROS in cancer cells. Since certain breast cancers overexpress the biotin receptor and absorb biotin with a higher efficiency, we hypothesize that conjugating biotin to ferrocene will increase the efficiency of ferrocene entering cancer cells, resulting in selective toxicity. Therefore, we have produced a library of biotin-ferrocene conjugates to test their ability to selectively enter cancer cells and generate ROS. Experiments were conducted utilizing ferrocene and a variety of conjugates (C1, C2, C3, 2) in both cancer (MCF-7) and non-cancer cells (HEK293).

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BIOL2019WADE5244 BIOL

Exploring the Endocrine Activity of Nitrate: Does Exposure Alter Hormone Levels and Reproduction in Adult Fathead Minnows?

Type: Undergraduate
Author(s): Caroline Wade Biology Hannah Nettelblad Biology
Advisor(s): Marlo Jeffries Biology
Location: Session: 2; 2nd Floor; Table Number: 5

presentation location

Endocrine disrupting compounds (EDCs) interfere with hormone production and action. EDCs typically mimic native hormones and often have a similar structure to natural hormones. While previous animal studies suggest that nitrate alters the synthesis of testosterone, nitrate is different than typical EDCs as its structure is not similar to that of any naturally occurring hormones. Given this and the environmental prevalence of nitrate, the objectives of this study are to 1) determine if nitrate acts as an EDC and 2) to better understand the mechanisms and effects of nitrate exposures on hormone production and reproduction. To achieve these objectives, groups of sexually mature adult fathead minnows were exposed to nitrate for 28 days. On days 7 and 28 of the exposure period, minnows were sacrificed for the collection of blood and gonads. The blood was used to evaluate hormone levels, while the gonads were used for gene expression analysis. Additionally, during the exposure, endpoints indicative of reproductive capabilities were also evaluated. There were no significant differences between exposure groups regarding gene expression, and there were no dose-dependent differences in egg production over the course of the breeding study.


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BIOL2019WINER58088 BIOL

Floral Herbivory in a Carnivorous Plant

Type: Graduate
Author(s): Zane Winer Biology
Advisor(s): John Horner Biology
Location: Session: 2; 3rd Floor; Table Number: 2

presentation location

Floral herbivory (florivory) can have direct effects on both female and male reproductive output. Damage to flower parts such as petals and anthers can also have potential indirect effects by altering floral attractiveness to pollinators. Because carnivorous plants live in nutrient-poor environments and have slow growth rates, these plants may be at increased risk of negative effects of florivory. However, there has been no study to investigate florivory in carnivorous plants. We conducted a two-year field study on an east-central Texas population of the carnivorous pitcher plant Sarracenia alata and its specialist herbivore Exyra semicrocea. Populations were surveyed for number of flowers attacked, and the mass of floral components was compared between attacked and unattacked flowers. In 2017, a mean of 65% of flowers were attacked at the end of the flowering season. Based on mass before dehiscence, the mass of anthers after florivory was 49.5% of unattacked anthers. There were no significant differences in the masses of other floral structures at the end of the season. In 2018, 38% of flowers surveyed were attacked. The mass of attacked ovaries was 47% that of unattacked, the mass of sepals and petals combined was 62.5% that of unattacked, and the stigma/style complex was 51.0% that of unattacked. The mass of attacked anthers before dehiscence was 18.7% that of unattacked anthers. This study shows that there was annual variation in both the proportion of flowers attacked in the population, and the extent of damage seen in floral structures. Future studies should examine the effects of florivory on pollen limitation, pollinator behavior, and recruitment in Sarracenia alata.

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BIOL2018ALENIUS27660 BIOL

Can Specialists Generalize? Diets of Texas Horned Lizards (Phrynosoma cornutum) in Small Texas Towns

Type: Graduate
Author(s): Rachel Alenius Biology
Advisor(s): Dean Williams Biology Tamie Morgan Geological Sciences

The Texas horned lizard (Phrynosoma cornutum) is considered a threatened species in Texas and Oklahoma, due to substantial range declines over the past several decades. Horned lizards are believed to be highly vulnerable to habitat alterations, due to extreme specialization on ants, particularly harvester ants (Pogonomyrmex spp.). I analyzed diets of Texas horned lizards from two small towns by identifying exoskeletons of prey items found in fecal pellets. I assessed dietary specialization by comparing diet to prey availability, based on pitfall traps and abundance of harvester ant colonies. My results found strong spatio-temporal variation with respect to prey abundance and consumption. Harvester termites (Tenuirostritermes cinereus) and big-headed ants (Pheidole spp.) accounted for over 70% of all prey consumed. Average consumption of big-headed ants was comparable to their abundance in pitfall traps, but consumption of harvester termites was much higher than their pitfall trap abundance. Consumption of harvester ants is strongly correlated with the number of harvester ant colonies within study sites and horned lizard home ranges. Dietary diversity and richness were positively related to the area of dense vegetation in sites and lizard home ranges. These results suggest horned lizards in these towns adjust diet in relation to prey availability, which is considered a characteristic of generalist predators. The superior nutritional value of harvester termites relative to similarly sized ants could explain the apparent lack of size-based prey preference in these horned lizard populations.

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BIOL2018BRUNS38844 BIOL

Reproductive effects of early life stage thyroid disruption in the fathead minnow

Type: Graduate
Author(s): Peter Bruns Biology Bethany Pierce Biology Mallory Seemann Biology
Advisor(s): Marlo Jeffries Biology

Exposure to contaminants during development has the potential to cause adverse biological alterations that can persist through depuration periods and into adulthood. This study examined the effects of chemically induced, early-life-stage thyroid disruption on endpoints associated with thyroidal and reproductive function in the fathead minnow (Pimephales promelas). Fish were exposed to propylthiouracil (PTU) from 1 to 43 days post hatch (dph) to induce hypothyroidism. At the end of exposure, length and weight were measured and samples were taken for gene expression analysis. The remaining fish were transferred to un-dosed water and raised to maturity and, at 164 dph, a 21-day breeding assay was performed. At the end of exposure, fish exposed to PTU had significantly reduced length and weight indicating successful thyroid disruption. There were also significant differences in expression of several genes involved in the thyroidal and reproductive signaling systems. After maturation, there were no significant differences in any morphological variables. During the 21-day breeding assay, fish from the PTU exposure group had significantly reduced overall fecundity relative to controls. Based on data collected so far, it appears that this reduction in fecundity is due to either ovarian dysfunction or alterations in reproductive behavior. The results show that early-life-stage hypothyroidism can affect reproductive function later in life even after thyroid related endpoints have returned to control levels.

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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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BIOL2018GERSTLE55536 BIOL

Mercury Risk to Piscivorous Wading Birds of the South Central United States

Type: Graduate
Author(s): Christopher Gerstle Biology Matthew Chumchal Biology Ray Drenner Biology
Advisor(s): Ray Drenner Biology Matthew Chumchal Biology

Mercury (Hg) is a toxic heavy metal that has contaminated all aquatic food webs and can pose a health risk to aquatic predators. Piscivorous birds are apex predators in aquatic systems that are exposed to mercury through the consumption of Hg-contaminated fish. Although there is extensive data on Hg concentrations in fish, the data on Hg concentrations in birds is relatively limited. I used a previously published relationship between Hg concentrations in piscivorous bird blood and Hg concentrations in prey fish to estimated Mg concentrations in the blood of four species of piscivorous wading birds in the south central U.S. [Little Blue Herons (Egretta caerulea), Green Herons (Butorides verescens), Great Egrets (Ardea albus) and Great Blue Herons (Ardea herodias)] from the concentration of Hg found in bluegill (Lepomis macrochirus). Estimated Hg concentrations in bird blood increased with the size of prey fish consumed and was lowest for Little Blue Herons and Green Herons, intermediate for Great Egrets and highest for Great Blue Herons. Estimated Hg concentrations in bird blood was greatest in ecoregions where conifer-adjusted mercury deposition was highest. Mercury risk to bird health varied with bird species and increased with Hg deposition. Little Blue Herons, Green Herons, Great Egrets and Great Blue Herons were at some level of risk in 14, 36, 86 and 100% of ecoregions, respectively. The threat of Hg to the health of piscivorous wading birds may not be unique to south central U.S. and may extend throughout the southeastern United States due to high Hg deposition and extensive forest coverage.

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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.

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BIOL2018MALMQUIST59917 BIOL

Development and use of a G. mellonella infection model to discover novel virulence mutants in B. anthracis

Type: Graduate
Author(s): Jacob Malmquist Biology
Advisor(s): Shauna McGillivray Biology

Understanding bacterial virulence is important because it provides insight into the molecular basis behind bacterial infections. With the decreased efficacy of antibiotics due to the development of drug resistance, this knowledge could be used to identify specific targets for new pharmacological targets thereby strengthening our arsenal against these pathogens. Currently, our main mechanism by which to evaluate in vivo virulence is the mouse model (Mus musculus). While this model is effective, there are substantial ethical and resource constraints associated with vertebrate use. In order to provide alternative in vivo testing models, this study investigated the invertebrate wax worm larvae, G. mellonella, as an in vivo infection model for B. anthracis. To validate the ability of G. mellonella to discern attenuated bacterial strains, previously identified virulence mutants were constructed and assessed. This model proved capable of distinguishing between virulent and avirulent strains. Next, we tested whether G. mellonella could identify novel virulence mutants. A small collection of transposon mutants was screened for deficits in reactive oxygen species (ROS) survival and iron acquisition using in vitro screens. This yielded 10 attenuated mutants. These mutants were then assessed in G. mellonella and 2 were found to have an in vivo phenotype. These results demonstrate the potential effectiveness of G. mellonella as a future infection model and could increase the efficiency in the identification of novel bacterial virulence mutants.

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BIOL2018MARTINEZ52539 BIOL

Effects of copper and temperature on the life stages of the invasive zebra mussel

Type: Graduate
Author(s): Julianna Martinez Biology
Advisor(s): Michael Misamore Biology

Dreissena polymorpha, zebra mussels, are an invasive species of freshwater bivalves that have recently spread into bodies of water across North America via the Great Lakes. Zebra mussels are mainly spread throughout the United States by their free-swimming larvae called veligers that are moved from waterbody to waterbody by human boat traffic, attributing to the success of their invasive spread. Once an adult zebra mussel population is established, they proliferate quickly and cause many problems to the ecosystem by their efficient filter feeding abilities. They also cause damage to boating and water treatment equipment by tightly attaching to many hard surfaces. Zebra mussels have recently entered many Texas waterways, indicating that they have possibly adapted to conditions outside of originally expected for a cold water species that are not representative of the Great Lakes region. The focus of this study was to look at various environmental factors which may affect zebra mussel survival and reproduction including temperature and the effects of a copper-based molluscicide, EarthTec QZ, as a potential mechanism of control. Zebra mussel survival and reproductive success were examined in various experiments to gain an overall understanding of the effects at all zebra mussel life stages.

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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.

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BIOL2018NAGEL5118 BIOL

The Effects of Inflammation on Dendritic Spine Density

Type: Undergraduate
Author(s): Sarah Nagel Biology Frenki Behaj Biology John Figg Biology Christopher Hagen Biology Ryan Madigan Biology Claire Munster Biology Michaela O'Connor Biology
Advisor(s): Michael Chumley Biology Gary Boehm Psychology

Alzheimer’s Disease (AD) is a neurodegenerative disease that is characterized by deficits in learning and memory. AD pathology is associated with neuronal death through the accumulation of amyloid beta (Aβ) plaques in the synapses. Our lab has previously demonstrated that Lipopolysaccharide (LPS), a component of gram-negative bacteria, induces an inflammatory response that increases Aβ found in the brain. Dendritic spines are projections on dendrites that may or may not be synapsing with an axon. Previous research indicates that there is a correlation between the number of properly functioning synapses and the number of dendritic spines. In this study, LPS was administered to induce inflammation, stimulating Aβ production. We then quantified dendritic spine density in order to compare dendritic spine density in the hippocampus of both LPS- and saline-treated groups. Contrary to our hypothesis, we saw a non-significant increase in dendritic spine density following LPS treatment, when compared to saline controls.

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BIOL2018PIERCE21782 BIOL

Seeing is Believing: Developing Methods to Assess the Effects of Pollutants on Vision

Type: Undergraduate
Author(s): Bethany Pierce Biology Julie Krzykwa Biology
Advisor(s): Marlo Jeffries Biology

There has been mounting concern from both scientists and the public regarding the presence and biological effects of emerging contaminants (ECs) in the environment. ECs can be defined as contaminants that are not currently subject to routine monitoring programs or regulatory standards, but that have the potential to cause adverse environmental or human health effects. These pollutants are being found in increasing levels in aquatic environments, and as such, the possible health impacts of these contaminants have become a growing focus of scientific research. Some classes of ECs, especially those that disrupt neurological development or thyroid hormone levels, have the potential to alter the growth, development, and function of the eyes. For many organisms, eyesight is crucial to survival as it allows them to avoid danger, obtain food, and perform many other important activities. However, reliable methods for testing the effects of ECs on vision are scarce, so the full impact of many ECs remains unknown. As such, this project aimed to determine dependable ways to measure visual development and function in the fathead minnow, a small fish frequently used to screen for chemical toxicity and adverse effects. We found that the feeding assay was a straightforward and promising option for measuring vision because it estimated the average prey capture ability of a group in a relatively short amount of time. We also found that the optomotor assay, while compelling, presented no significant differences between groups for the variables tested. However, there were practical differences observed throughout the trials, indicating that although the assay is complex, further testing and development could transform it into a reliable source of data.

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BIOL2018QUINN40980 BIOL

Hybridization Potential Between the Invasive Zebra and Quagga Mussels

Type: Undergraduate
Author(s): Hunter Quinn Biology
Advisor(s): Mike Misamore Biology

Zebra and Quagga mussels are aquatic and highly invasive freshwater bivalve molluscs native to Eurasia. They have spread at an exponential rate into bodies of water throughout the country by means of our interconnected waterway. Prior analysis of their distribution has determined a consistent global pattern in which a population of zebra mussels initially invades a body of water and subsequently, a population of quagga mussels is established in the same region. Despite differential habitat preferences, both species have been found to live and reproduce in the same location. Since both species exhibit broadcast spawning as a reproductive mechanism, the potential for hybridization exists; this potential was analyzed via evaluating the initial fertilization and early embryonic cleavage stages required for production of viable hybrid offspring. A series of hybridization crosses were performed and compared against a control. Fertilization events observed and analyzed included motility and chemotaxis, the acrosome reaction, sperm binding and entry into the egg cytoplasm, and finally cleavage and early development. Inability to produce viable offspring suggests a hybridization-block has been established between the two species at the level of fertilization or early development.

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BIOL2018SEEMANN60152 BIOL

Investigating the causes of reproductive impairment following thyroid disruption

Type: Undergraduate
Author(s): Mallory Seemann Biology Peter Bruns Biology
Advisor(s): Marlo Jeffries Biology

Some classes of endocrine disrupting compounds in the environment have the ability to alter thyroid function. Such thyroid disrupting compounds are known to influence growth and development, but recent studies suggest that thyroid disruption can also have adverse effects on reproduction. A recent study in the Jeffries lab demonstrated that early-life stage thyroid disruption caused decreased reproductive output in fathead minnows (Pimephales promelas), even after a prolonged period of depuration. However, the mechanisms connecting early life stage thyroid disruption to altered reproduction during adulthood remain elusive. This study sought to determine whether alterations in reproductive success following thyroid disruption were a result of male or female reproductive performance in an effort to narrow potential mechanisms by which thyroid disrupting compounds alter reproduction. The results of this study bring insight to the underlying cause of decreased reproductive output following thyroid inhibition.

(Presentation is private)

BIOL2018SMACK21567 BIOL

Prey Preference in the Carnivorous Pitcher Plant, Sarracenia alata

Type: Undergraduate
Author(s): Caleb Smack Biology Lauren Rogers Biology
Advisor(s): John Horner Biology

Carnivorous plants occupy nutrient-poor soils and have evolved traits that allow them to obtain nutrients by capturing and digesting insects. The pale pitcher plant, Sarracenia alata, uses passive pitfall traps to capture their insect prey. Although studies have examined prey composition for S. alata, it is unknown whether this species is selective in prey capture or whether it captures insects in proportion to their abundance in the environment. The purpose of this study was to compare prey capture of S. alata pitchers with the available insects to determine whether this species is selective in prey capture. The available insects were sampled using artificial sticky traps in the vicinity of the pitchers. The insects in the study were identified first to the taxonomic level of order and then further identified to "morphospecies" as a means of examining preference on a finer scale. The relative proportions of insects in specific orders differed between artificial traps and plants. Although dipterans were a major component of capture in both artificial traps and plants, the relative proportions of morphospecies differed between the two. These results support the hypothesis that S. alata is selective in its prey capture, but further studies are needed that use different methods of measuring the available insects in order to avoid potential bias.

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BIOL2018SMITH20222 BIOL

The Effects of Microgravity on Penicillium Mold Growth

Type: Undergraduate
Author(s): Laura Smith Biology Ryder Huskins Biology Gabriel McCarthy Biology Ethan Moore Biology Ian Ray Biology Kenneth Sanders Biology
Advisor(s): Laura Smith Biology

Our team will answer the question how Penicillium mold grows in a microgravity environment versus Earth’s gravity. This question answers or sparks several other questions such as is it a viable solution for some antibiotics in space or how do antibiotics like penicillin work in the body in space. Will it grow more or will it be the same or maybe grow less? The purpose of our experiment is to provide a viable solution to some bacterial infections in space. Bacteria in space tends to act more violently so maybe good bacteria or mold will act more furiously to kill those bacteria. Our hypothesis is that it will grow better. This is based off of the fact that in an earlier SSEP experiment the polymers absorbed more water. Which might be the same for organisms like mold so it would make it easier to absorb water. Plus with lower gravity organisms tend to grow larger at least that is many scientist hypotheses. So since there is practically no major gravity or forces in space may be the mold will grow larger than usual. Our group believes this based on the fact that we have researched.

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