Life History Theory predicts that growing up in certain environmental circumstances should promote the development of adult phenotypes that can survive in similar circumstances. Researchers have recently proposed that growing up poor should encourage eating strategies that promote survivability in resource scarce environments, with individuals reared in poorer circumstances eating comparable amounts of calories, regardless of energy need. Additional research indicates that childhood experiences with parental inconsistency, dangerous neighborhoods, development of an unpredictability schema (e.g., a mindset about the world, people, and future outcomes as unpredictable), and lowered body awareness predict this same pattern of results in adulthood. The purpose of the current research was to examine the impact of environmental conditions such as pregnancy stress experienced by the mother, family financial struggles, and predictability of the childhood environment on the emergence of eating in the absence of hunger in children ages 3-14. Results indicate that increased pregnancy stress and environmental unpredictability significantly predict eating in the absence of hunger.

Keywords: psychosocial stress, eating behavior, self-regulation, evolutionary psychology, health

Anxiety is an increasingly widespread mental health issue affecting a significant portion of the United States population. Further research in the field of mental health is beneficial to understanding the mechanisms that drive anxiety, and to discovering novel, therapeutic interventions. Using a rodent model to conduct this research is practical due to the morphological similarity of the rat brain to the human brain. We will examine anxiety- and fear-related responses in both male and female subjects that are subjected to either unpredictable or predictable threat. Unpredictable threats generate a state of anxiety, and predictable threats produce fear. Threat predictability will be manipulated by administration of temporally inconsistent, or temporally consistent foot shocks in an operant chamber. Equal numbers of males and females will be included within each group and the rats will be randomly assigned to either the temporally consistent or temporally inconsistent footshock condition. Animals will be tested over the course of three days; Day 1 is the contextual conditioning test day wherein the animal is exposed to the novel environment and the initial presentation of the foot shocks. Day 2 is the memory test day, where animals are returned to the test chamber, but no shock is given; day 3 . Day 3 is the reinstatement test where the animal is placed back into the chamber and one footshock is administered. Anxiety and fear will be assessed by measuring rearing (anxiety-related) and freezing (fear-related) behaviors in the test chamber on each test day. Sex differences in anxiety and fear that are generated by varying threat predictability will be determined. These results will provide insights into the role of potential sex differences in anxiety and fear-related behaviors.

It is commonly understood that as we age, memory tends to decline. Memory failures can have severe consequences for older adults if they forget important things, such as taking daily medication. Recently, researchers have found that younger and older adults tend to remember forgotten information as having been less important than remembered information (Castel et al., 2012; Witherby, Tauber, Rhodes, & Castel, in prep). This effect is called the forgetting bias. In the present experiment, we investigated why older and younger adults show the forgetting bias.
Older and younger adults studied words that were assigned a value indicating the importance of remembering the word. Following study, they took a free-recall test. After repeating the study-test procedure four times, participants took a surprise test. On the test, they were shown each word and asked (1) if they remembered it on the free-recall test and (2) to recall the point value assigned to it during the study phase. Younger and older adults used their memory judgment on the surprise test as an anchor for recalling the value. Specifically, words that were judged as remembered were given high values, whereas words judged as forgotten were given low values. Thus, one reason why both older and younger adults show the forgetting bias is because they rely on their memory of past test performance. Future work is needed to examine whether a forgetting bias is shown with more meaningful information as well as ways to eliminate the bias.

The purpose of this study was to test the hypothesis that overt or covert echoic responding in the presence of an image is necessary for learning new verbal labels from exposure to contiguous presentations of words and images. (Horne & Lowe, 1996). This hypothesis predicts that seeing an image after hearing the associated verbal label leads to superior recall compared to seeing the image only before the verbal label is heard. Four children (3-6 years old) participated in a single-case design study that used an alternating-treatments design to evaluate the effects of stimulus presentation arrangement on subsequent recall of verbal labels. Each participant was exposed to six sessions that alternated across two conditions; word-first and image-first. In each session, the participants observed 20 pictures of four novel birds paired with their spoken names. In the word-first condition, the word and image were presented simultaneously but the image remained on the screen after the offset of the verbal stimulus. In the image-first condition, the image was initially displayed by itself, followed by the verbal label and the simultaneous offset of both. After each session received test for both verbal recall and recognition of the bird names. Compared to a prior experiment that was identical except that there was no overlap between image and word presentation, participants in the current experiment performed with slightly greater accuracy on the recall and recognition tests, but typically recalled only one or two labels after each session, with no difference between the image-first and the word-first condition.

The importance of cannabinoid receptors has risen in recent years due to the increasing number of states that have legalized marijuana; 28 states allow the usage of medical marijuana and 7 states allow recreational use ("28 Legal," 2017). Previous research from our lab has explored coping with multiple instances of reward loss when exposed to large, chronic doses of cannabinoid agonist WIN 55, 212-2 (WIN, 10 mg/kg). When chronically exposed rats received a consummatory successive negative contrast (cSNC) downshift of 32% to 4% sucrose, they were less able to cope with the subsequent autoshaping downshift of 12 pellets to 2 pellets. Additional autoshaping research from our lab has shown multiple downshifts in autoshaping to be successful in obtaining contrast effects. The present research combined this procedure with occasional acute doses of WIN (1 mg/kg) to determine if only one kind of downshift experience, autoshaping, was sufficient to produce less coping efficacy if repeated. Rats were randomly assigned to either WIN or vehicle control groups, and then trained in acquisition with discrete lever presentations where one lever was always followed by the delivery of 12 pellets, and a second lever was always followed by 2 pellets. After acquisition, rats received downshift sessions once per week, wherein the lever previously associated with 12 pellets was downshifted to only be followed by 2 pellets. Prior to each of 4 downshift sessions, rats received intraperitoneal injections of either WIN or vehicle solution. Lever presses to each lever during discrete “forced choice” and simultaneous “free choice” trials and head entries into the cup where food was delivered, or “goal entries,” were both recorded to assess preference and explore downshift effects. Although acute WIN administration did not affect lever preference relative to vehicle controls, it did result in decreased lever pressing in favor of goal tracking during the downshift. Therefore, WIN seems to encourage rats to be more focused on the outcome instead of responding to signals for the outcome, which may have implications for reducing impulsive behavior despite extensive training.

Prior work has found that religious individuals experience greater concerns about mortality when thinking about Jesus taking human form (Arrowood & Cox, 2018). Building on this, the present research examined how intrinsic religiosity (i.e., a more “mature” form of religion with a development for a deeper, more meaningful relationship with God) would moderate these effects. Christian individuals were asked to complete the Religious Orientation Scale, followed by reading an essay that either described Jesus as being fully human or a description of His lost years (i.e., neutral condition). The dependent variable consisted of people’s fear of mortality. The results revealed that low intrinsic individuals experienced a heightened fear of death following a creaturely Jesus prime. High intrinsic individuals, however, did not differ from neutral conditions. This study suggests that intrinsically valuing religion can serve as a buffer against existential anxieties stemming from humanistic concerns.

Anxiety disorders are a widespread and serious health concern currently affecting approximately 18% of the adult population per year (Kessler, et al., 2005); thus, there is a strong need to develop and improve therapeutic treatments for anxiety. Moreover, because sex differences in the prevalence of affective disorders in humans are well documented, this study involves both male and female rats. Vocalizations allow for a dynamic assessment of an animal’s emotional state. The ultrasonic vocalizations (USVs) of rats are produced at frequencies above the level of human hearing. USVs are often used as a tool to assess the emotional state of rats. Previous research has identified two main call types for rats: 22 kHz (related to strongly negative emotion) and 50 kHz. 50 kHz calls can then be further broken down into constant frequency (CF) and frequency modulated (FM) subtypes. FM calls are produced with a bandwidth greater than 15 kHz; these calls are related to positive emotional states. Whereas, CF calls are produced with a constant frequency and a bandwidth less than 10 kHz. Our lab hypothesizes that CF 50 kHz calls are expressions of anxiety in rats. Our lab has previously explored the vocalizations of rats across a continuum of negative affective state (i.e., from anxiety to fear) within a single testing session using a sequence of temporally consistent mild footshocks. The current experiment explores USV production in male and female rats when the temporal predictability was reduced by randomizing the time between footshocks. We utilized an unpredictable footshock paradigm with the goal of increasing or prolonging a state of anxiety as compared to our previous procedure. In this paradigm, shocks were administered across three successive days: on Day 1, mild footshocks were administered in a pseudo-randomized pattern, on Day 2, subjects were returned to the same context but did not receive footshocks, and on Day 3, a single reinstatement shock was administered. Differences in USV calling behavior across test days will be explored in male and female rats. In addition to USVs, rearing and freezing behavior were also recorded and used to assess anxiety and fear. These results will enhance our understanding of vocal expression of emotional states in rats, which improves the dominant animal model used to study anxiety disorders and potential therapeutic interventions.

Discrimination learning involves responses (e.g., cheering for TCU) that are rewarded under some conditions (e.g., at a TCU football game) but not others (e.g., in the library). Occasion setting involves a higher-order discrimination in which one stimulus (i.e., the occasion setter) signals whether response to a second stimulus (i.e., a discriminative stimulus) will be rewarded (e.g., followed by food) or not. In the current experiments, pigeons were trained in a spatial occasion setting task in which an occasion setter (i.e., a colored background) provided information about if and where to respond relative to a discriminative stimulus that served as a landmark (i.e., a colored box embedded within the occasion setter). These experiments examined the effect of spatial ambiguity on occasion setting. In Experiment 1, pigeons were trained on a task in which spatially stable occasion setters gave information about where to respond relative to spatially unstable landmarks (←YB, ZB→, ←WA, XA→, ←C→). In Experiment 2, a different set of pigeons were trained with both a spatially unstable and two spatially stable occasion setters paired with landmarks that were spatially unstable (←WA, WB→, ←XA, YB→, ←C→). Transfer tests showed that the stable occasion setters were able to control responding to spatially unstable landmarks that they had not been paired with in training.

In a delayed serial same-different discrimination procedure, one stimulus is followed by either the same or a different stimulus after a brief delay. To receive reinforcement (e.g., food), the subject must respond “same” when the two stimuli match and a “different” response when they differ. The individual stimuli change across trials, so it is the relation between stimuli that signals the correct response. A differential outcomes procedure has been shown to facilitate learning of some discriminations but had not been tested with rats in a relational discrimination. In a differential outcomes procedure, one reinforcer (e.g., pellets) follows one response (e.g., a correct “same” response) and a different reinforcer (e.g., sucrose) follows another correct response (e.g., a correct “different” response). In the control condition, the same reinforcer follows a correct “same” and “different” response. In the current experiment, half of the rats were trained on a serial same-different discrimination using a differential outcomes procedure and the other half were in the control group. Stimuli were presented and responses recorded on an iPad mounted at the rear of an operant box. After the rat touched the sample stimulus (i.e., the first stimulus) it was removed for a delay of 500, 1500, 3000, or 6000 ms before the rats were presented with the comparison stimulus (i.e., the second stimulus). After touching the comparison stimulus, a response button appeared on each side of it. One button represented a “same” response and the button on the other side a “different” response. After training, rats were tested to determine if learning of the same-different relation would transfer to novel stimuli. The results showed no transfer of learning, and a decrement in performance on trials with the original training stimuli.

Individuals with Autism Spectrum Disorder (ASD) tend to have difficulties with emotional and social interactions (e.g., Stone & Caro-Martinez, 1990). It is possible that they also have deficits in their ability to monitor their learning of social and emotional information. If so, this could have negative downstream effects on their later memory. In the present experiment, we investigated the influence of social and emotional pictures on adolescents’ (with and without ASD) monitoring of learning and memory performance. To do so, participants studied 60 pictures that were positive or neutral and that either had a social component (e.g., a couple at their wedding, a child reading a book) or did not (e.g., ice cream, screwdriver). After studying each image, participants made a judgment of learning (JOL) predicting the likelihood that they would remember that picture on a later test. Finally, participants took a free-recall test. Overall, adolescents with ASD provided lower JOLs and demonstrated lower memory performance than did adolescents without ASD. In addition, all participants gave higher JOLs to positive pictures than to neutral pictures, and recall was also superior for positive relative to neutral pictures. Finally, participants gave higher JOLs to pictures with a social component than to pictures without a social component, although this dimension did not influence their memory. These results suggest that monitoring of learning is not impaired in adolescents with ASD. Thus, although adolescents with ASD tend to remember less than adolescents without ASD, this finding does not appear to be caused by monitoring deficits.

ClpX is a regulatory ATPase that functions along with ClpP as part of the intracellular bacterial ClpXP protease. Previous research from our group has shown that genetic loss of ClpX (∆ClpX) in Bacillus anthracis Sterne increases susceptibility to antimicrobial agents that target or interact with the cell wall including penicillin, daptomycin, and LL-37. In order to gain a better understanding of ClpX function in B. anthracis Sterne, a microarray analysis comparing WT and ∆ClpX gene expression was performed in B. anthracis. We found that LrgAB, a negative regulator of autolysis, was significantly downregulated in the ∆ClpX mutant and this finding was confirmed with QPCR. In order to determine whether LrgAB also had a role in antibiotic resistance in B. anthracis, we made a genetic deletion of LrgAB (∆LrgAB) and found it has similar phenotypes to ∆ClpX in B. anthracis. To see if these findings were consistent in other gram- positive pathogens, we expanded our research to Staphylococcus aureus, the leading cause of skin and soft tissue infections. We constructed a ∆ClpX mutant in the Newman strain of S. aureus and found it also exhibited sensitivity to cell wall active antimicrobial agents. Loss of ClpX in S. aureus also resulted in decreased expression of LrgAB by QPCR. Lastly, we examined a S. aureus ∆LrgAB mutant and observed an increase in antibiotic susceptibility. We conclude that ClpX plays a role in resistance to cell wall active antimicrobials in both B. anthracis and S. aureus, and that this is connected to its regulation of LrgAB.

Breast cancer is a growing problem in the United States and worldwide. It takes the lives of approximately 40,000 U.S. women a year. 1 in 8 U.S. women will develop breast cancer during the course of their lifetime and it continues to be the most commonly diagnosed cancer in women. Clearly, this is a serious issue that must be solved. Current chemotherapy treatments often result in widespread cell death, including the killing of healthy cells. Therefore, it is necessary to find alternative treatments that specifically target cancer cells. Many breast cancer cells over express estrogen receptors, which are vital to the rapid cell division and growth of tumors. Estrogen is a steroid hormone that enters the cell, binds to its receptor, translocates to the nucleus, and leads to gene expression. Previous work from our group has resulted in the development of a drug which targets estrogen receptor positive breast cancer cells called Est-3-Melex. The drug contains a DNA methylating group (Melex) conjugated to estrogen. The mechanism of action of the drug is by the binding of the estrogen portion of the molecule to its receptor that ultimately translocates to the nucleus. While in the nucleus, the Melex portion of the compound is brought in close proximity to the DNA and methylates the adenines, eventually resulting in cell death. Essentially, this is a receptor targeted cancer therapy. In order to test the toxicity of this drug, we utilized a MTT cytotoxicity assay, which quantifies the amount of cell death. Est-3-Melex was more toxic to cancer cells that overexpressed the estrogen receptor compared to those that did not. Treating the estrogen receptor positive breast cancer cells with excess amounts of estrogen inhibited Est-3-Melex-induced cell death. Fluorescence imaging was also utilized to visualize localization of the drug. A fluorescent tag was attached to Est-3-Melex and introduced into estrogen receptor positive breast cancer cells. The results showed the drug localized to the nucleus and this localization was inhibited by estrogen. Our results suggest that Est-3-Melex is effective in specifically killing estrogen receptor positive breast cancer cells by binding to the estrogen receptor. Additional investigations are underway to identify the mechanism of cell death.

The effects of the thyroid axis on metabolism, growth, and development are well documented. However, there is a paucity of information on the role of thyroid hormones in the development of the immune system. Therefore, the goal of this study was to determine the effects of early life stage exposures to thyroid-altering chemicals on the developing immune system using the fathead minnow (Pimephales promelas) as the model, an organism commonly used in toxicity testing. This was accomplished by measuring differential expression of several immune-related genes in fish exposed to various doses of propylthiouracil (PTU, a thyroid-inhibitor) and thyroxine (T4, a thyroid-stimulator) sampled at 7 and 35 days post hatch (dph). Fish exposed to PTU exhibited significant increases in rag2 expression at 7 dph, decreases IgLC1 expression of at both 7 dph and 35 dph, and decreases in IgLC3 expression at 7 dph. In contrast, T4-exposed fish showed elevated rag1 and rag2 expression at both 7 and 35 dph, increased IgLC2 expression at 7 dph, and upregulation of ikaros at 35 dph. The results of this study indicate that exposure to thyroid altering chemicals influences the expression of several genes associated with proper immune system development, indicating that thyroid hormones regulate various aspects of immune development. These findings provide evidence that exposures to environmentally-relevant compounds that modulate thyroid function may lead to improper immune system development, which is likely to adversely affect overall organism health.

Recent research has identified dung beetles as bioindicator species found in a wide range of environments. Bioindicators function as monitors for the health of an ecosystem, which can be determined by analyzing the function, population, or status of the species in said environment. The purpose of our project was to determine if dung beetle diversity and abundance differed between primary and secondary rainforests. We conducted a study in the transition zone between tropical wet forest and premontane rainforest at the El Jamaical Field Station in Costa Rica. We acquired feces from both cows and horses near the field station. For trial 1, we made four bait traps using cow feces and one control for each of the forest types. Within each forest type, we placed the bait traps 25 meters apart. We then repeated the experiment using horse feces for trial 2. Traps sat for a period of 24 hours to allow dung beetles time to burrow into the traps. We then collected and processed the samples. Processing consisted of sifting and breaking down the feces in a meticulous manner to find, collect and identify all dung beetles present. We identified a total of 303 beetles in trial one and 0 in trial 2.

Mercury (Hg) is a hazardous contaminant that can be transferred from aquatic to terrestrial environments by emerging aquatic insects. Terrestrial predators, such as spiders, that live along shorelines of water bodies may consume emerging aquatic insects and become contaminated with Hg. Mercury-contaminated spiders may pose a risk to arachnivorous songbirds. The degree to which most families of spiders are contaminated with Hg and the risk they pose to songbirds is not well understood. The objectives of this study were to determine 1) Hg concentrations in two families of shoreline spiders (long-jawed orbweavers, [Tetragnathidae] and crab spiders [Thomisidae]) and 2) determine the risk these spiders pose to arachnivorous birds. We collected representatives from two families of spiders from the shorelines of 10 ponds located at the LBJ National Grassland in north Texas, USA. Both spider taxa in the present study were contaminated with Hg, however long-jawed orb weavers had significantly higher concentrations of Hg in their tissues than crab spiders (p < 0.001; average Hg concentration = 346 ng/g and 35.7 ng/g respectively). We calculated wildlife values for various songbirds to determine health risks that these Hg-contaminated spiders may pose to songbirds. Spider-based wildlife values revealed that one of the families of shoreline spiders, Tetragnathidae, had concentrations of MeHg high enough that they may pose a risk to arachnivorous songbirds that consume spiders along the shorelines of ponds.

Mercury (Hg) is a toxic environmental contaminant formed in aquatic systems by bacterial methylation of inorganic mercury deposited from the atmosphere. Historically Hg contamination of food webs was thought to be restricted to aquatic systems. However recent research has shown that emergent aquatic insects such as dragonflies are contaminated with Hg as aquatic larvae, and then transport it to terrestrial ecosystems when they emerge from the water as adults. Terrestrial predators such as birds can be contaminated with Hg when the consume Hg-contaminated dragonflies. Because dragonfly larvae are top predators in aquatic systems, they contain high concentrations of Hg when they emerge from aquatic systems and can potentially pose a threat to the health of birds that feed on them. The objective of this study was to estimate the Total Hg (THg) concentrations in dragonflies across ecoregions in the South Central U.S. and the hazard Hg-contaminated dragonflies pose to dragonfly-consuming birds. I estimated THg concentrations in dragonflies by using published data on THg concentrations in predatory fish (pF) in 14 ecoregions and converting it to THg concentrations in gomphid dragonflies (gD) assuming a linear relationship (gD) = 0.0856(pF) + 25.92 constructed using data from Haro et al. 2013. The variation of predicted dragonfly THg was mapped by ecoregion using GIS software. GIS analysis tools were used to assess the risk the predicted THg in dragonflies that would pose a health hazard to dragonfly-consuming red winged blackbirds (Agelaius phoeniceus) in each ecoregion.

Mercury (Hg) is a highly toxic environmental contaminant found in all waterbodies on earth. Emergent aquatic insects (like mosquitoes) transfer Hg from the aquatic systems to terrestrial consumers such as spiders. The objective of this study was to examine Hg concentrations in larval mud daubers (Sceliphron caementarium) and their spider prey in mud dauber nests. Adult mud daubers capture spiders with a paralyzing sting to use as the food source for the larvae in their nest. I collected 350 mud dauber nests from three bridges on the Trinity River and one building 40 m inland from the Trinity River in Fort Worth, TX. The nests contained 74 mud dauber larvae and over 2,000 spiders of five different families. I used a Direct Mercury Analyzer to determine the total Hg concentration of mud dauber larvae and five spider taxa. All mud dauber larva and spiders were contaminated with Hg. The inland site had the lowest concentration of Hg in the spiders, suggesting that the spiders at this site were more reliant on low Hg terrestrial prey than high Hg aquatic prey. This is the first study to demonstrate that mud daubers nesting along river systems are part of the mercury cycle because of their use of shoreline spiders as prey for their larvae.

Leaf cutter ants are the rainforest’s most prolific herbivore, eating more vegetation than any other type of creature. The ants have a profound effect on the Neotropical ecosystem, for they improve the richness of the soil, and, by removing leaves from the trees, allow sunlight to reach the lower levels of the forest, facilitating plant growth and diversity. Leaf cutter ants are selective in the plant materials they harvest. The goal of this study is to determine whether leaf cutter ants have a preference for fragile versus tough leaves by examining the relationship between level of leaf damage by leaf cutter ants and leaf toughness among a number of plant species. Leaves damaged by leaf cutter ants of several plant species were identified and collected from the trails of two ant nests in El Jamaical Field Station in Costa Rica. Area of leaf cutter herbivory were traced and recorded as the measurements for level of leaf herbivory. Leaf toughness was quantified as the force required for tearing the leaf apart by using a gravity-based tearing device. From the obtained data, we will examine the level of leaf herbivory of each leaf of the same species against its toughness to see whether leaf cutter ants prefer cutting fragile leaves over tough leaves in order to minimize energy cost. We will also compare this foraging pattern between species to see whether there is a variation in the ants’ preference among different plant species.

Over the last few decades, there has been increasing concern regarding the environmental presence and biological effects of endocrine disrupting compounds. Studies aimed at determining the adverse impacts associated with exposures to thyroid disrupting compounds have focused primarily on the ability of such compounds to alter patterns of growth and development; however, the actions of thyroid hormones extend well beyond these basic functions. As such, there is a need to investigate the potential for thyroid disrupting compounds to alter other physiological processes. Recent studies have suggested a role for thyroid hormones in the regulation of immune function. As such, it is reasonable to suspect that exposure to endocrine disrupting chemicals that impair thyroid activity will lead to alterations in immune function and subsequent changes in pathogen and disease resistance. Using the fathead minnow (Pimephales promelas) as a model organism, this study sought to determine the impact of propylthiouracil (PTU, a known thyroid inhibitor) on various aspects of immune function including immune gene expression, spleen index and pathogen resistance. To achieve this, male fathead minnows were divided into two groups – a control and a PTU-exposed group. Following a 21day exposure period, both groups were challenged with the pathogen Yersinia ruckeri, and mortality was monitored for 14 days to assess pathogen resistance. In addition, tissues (i.e., liver, spleen and kidney) were sampled at 8 hours and 72 hours post infection for the assessment of immune gene expression and spleen index. PTU exposed males were less able to survive pathogen infection relative to the controls. In addition, PTU-exposed males had significantly lower spleen index than the controls following injections, suggesting that they had a reduced ability to elicit an immune response. Gene expression of certain immune genes also showed a change in pattern of expression, signifying potential pathways and proteins that are particularly affected by thyroid hormone presence. These results show that chemically-induced decreases in thyroid hormone levels can suppress immune function and demonstrate that the immune system is a target for thyroid disrupting chemicals.

Neotropical rain frogs serve as an indicator of habitat and ecological disruption in tropical rainforests through species-specific response to environmental stimuli. These responses are reflected in preference of habitat, such as primary or secondary forest, which may provide insights into the health and stability of not only Neotropical rain frogs and amphibians, but also of the surrounding ecosystem. We studied the diversity and abundance of rain frogs at the El Jamaical Field Station in Costa Rica, located in a transition zone between tropical rainforest and premontane rainforest, by overturning leaf litter along previously established trails that passed through both forest types, photographing found individuals, and recording discovery locations on a map. Focusing our study on the primary and secondary forests, we predicted that the diversity and abundance of rain frogs would be greater in the primary forest than in the secondary due to differences in diversity of trees and flora, humidity, temperature, and light levels. Data analysis will include species identification, proximity to dry streams, and comparison between primary and secondary forest.

The Syr Darya, one of the largest rivers in southern Kazakhstan, is a major source of freshwater feeding the Aral Sea. In the 1950s, water was diverted from the Syr Darya to support agricultural production leading to the drying of the Aral Sea, which has been characterized as one of the worst environmental catastrophes in modern day history. Mismanagement of these diverted waters has paved the way for potential surface water contamination in the Aral Sea Basin. While efforts to revive the Aral Sea are underway, few investigations have sought to assess the impacts of potential heavy metal contamination in the Syr Darya Watershed. As such, the goal of this study was to assess the presence and biological effects of heavy metal contaminants in the Syr Darya. This was accomplished by collecting water and sediment samples from five sites and roach (Rutilus rutilus) samples from three sites along the Syr Darya. Water, sediment, and roach muscle tissue samples were analyzed for a suite of contaminants, while roach liver, brain, gonad, and gill tissues were analyzed for the expression of genes considered to be biomarkers of heavy metal exposures (e.g., metallothionein and superoxide dismutase). Water and fish muscle tissue analysis revealed the presence of multiple heavy metals above local regulatory limits. Roach fish from two of the three sites experienced alterations in the expression of genes considered biomarkers of contaminant exposure suggesting that chemical loads at some of the sites in the Syr Darya were sufficient to induce biological effects. Data collected as part of this study will be utilized to complete an ecological risk assessment of the Syr Darya River basin.

Alzheimer’s disease is a neurodegenerative disorder characterized by the presence of amyloid beta (Aβ) plaques. This pathology results in neuronal dysfunction and eventual cell death. Aβ plaques come from the buildup of beta-amyloid protein which clump together and block cell-to-cell signaling at synapses. To stimulate Aβ production, our lab uses an inflammation model utilizing lipopolysaccharide (LPS) injections. When mice are given intraperitoneal LPS injections over the course of one week they show a significant increase of Aβ in the brain. When a second course of LPS is administered following a two-week recovery period, Aβ levels return to baseline levels. The initial exposure to LPS protects the mouse from a second exposure, preventing further increase in the Aβ. One likely explanation is that the initial exposure primes the immune system, enabling the mouse to quickly initiate an antibody response upon subsequent exposure to LPS. The objective of the present study was to investigate the antibodies produced after the second course of LPS in 5xFAD mice. Plasma antibody levels were measured, and co-localization of antibodies around hippocampal Aβ plaques was investigated. We found that mice who received a second course of LPS injections had a significantly higher amount of IgG co-localized around plaques compared to non-treated control animals. This correlated with higher levels of IgG in the plasma. This data suggests that LPS exacerbates the antibody response in 5xFAD mice, and that these antibodies may specifically target Aβ.

Changes in early physiological development due to chemical effluent exposure can be determined by measuring the levels of gene expression. Genes involved in cardiovascular and neurological development, as well as growth, serve as sensitive endpoints in toxicity tests involving the use of larvae. The purpose of this research was to determine when during development the level of gene expression was high enough for contaminant-induced decreases in expression to be detected. A suite of genes involved in growth, cardiovascular and neurological development was examined in embryos and larvae from 0 to 11 days post hatch. This information was used to determine time points at which selected genes were most highly expressed. For the growth-related genes, expression levels of growth hormone (gH) were highest at Days 4-7 and 11, levels of growth hormone receptor (gHR) at Days 1-7 and 11, and levels of insulin-like growth factor (igf1) at Days 4-11. For the thyroid hormone receptors, thyroid hormone receptor-α (TRα) showed highest expression levels at Days 3-11 and thyroid hormone receptor-β (TRβ) showed highest levels at Days 2-5 and 9. For the deiodinase enzymes, deiodinase-1 (Dio1) expression levels were highest at Days 2-3 and 7-11, levels of deiodinase-2 (Dio2) were highest at Days 7-11, and levels of deiodinase-3 (Dio3) were highest at Days 1-5. Vegfa, a gene involved in cardiovascular development, had levels of gene expression that were highest at days 7-11. HuC, a gene involved in neurological development, had the highest level of gene expression at days 7-11. When the level of expression of these genes is highest is when they have the greatest potential to be used in toxicity tests to measure alterations in expression.

Cancer is the second-leading cause of death in the US. Cancer cells are characterized by loss of regulation of the cell cycle that results in uncontrolled proliferation. To drive this high rate of cellular division, cancer cells have mutated to increase uptake of important nutrients including glucose and vitamins by increasing the number of glucose receptors and vitamin transporters, including biotin receptor, on their surface. Due to this difference in expression of biotin receptor between cancer and normal cells, research focusing on the use of biotin-conjugated molecules has gained attention as a method for anticancer drug delivery.
Another characteristic unique to certain cancer cells is that they exhibit dysregulation in normal cellular redox balance, such that the cellular environment becomes more reducing. A more reducing environment favors the generation of reactive oxygen species (ROS). Many metal-based anticancer drugs have taken advantage of this feature of cancer cells in an attempt to increase the levels of ROS to the point that harmful oxidation reactions occur that lead to cell death. Specifically, the iron atom of ferrocene has been shown to lead to the generation of damaging ROS upon oxidation from Fe2+ to Fe3+.
A problem with current cancer treatment is that the chemotherapeutics often are not specific to cancer cells and can lead to negative side effects. As a result, anticancer drugs with high specificity and cytotoxicity are needed to improve treatments. This research project focuses on testing the cytotoxicity of a variety of biotin-ferrocene derivatives on cancer (HeLa) and non-cancer (293HEK) cell lines. HeLa cells are known to express high levels of biotin receptor and are predicted to have more reducing cellular environments; additionally, 293HEK cells express low levels of biotin receptor and are predicted to have less reducing environments. The tested compounds have three main features: a biotin moiety, a ferrocene core, and a variable linker covalently bound to the ferrocene moiety. We hypothesize that the biotin-containing compounds will enter HeLa cells more efficiently than 293HEK cells, allowing for the ferrocene moiety to reduce oxygen, leading to increased ROS generation and cell death.
Here, we demonstrate that ferrocene shows dose-dependent cytotoxicity specific to HeLa cells, while one of the compounds shows dose-dependent cytotoxicity specific to 293HEK cells. Interestingly, two of the compounds show dose-dependent cytotoxicity to both cell lines. These findings are particularly intriguing in that there appears to be a difference in specificity between some of the compounds. However, future studies are required to reveal how these differences in cytotoxicity are related to the differences in chemical moieties and by what mechanisms these compounds are acting to cause specific cytotoxicity.

Most plants acquire mineral nutrients from the soil. However, in nutrient-poor environments, some plants have evolved carnivorous traits that allow them to obtain nutrients by capturing and digesting insects. For example, the carnivorous pitcher plant Sarracenia alata uses passive pitfall traps to capture their insect prey. Although studies have examined prey composition for S. alata, few have included a comparison to the insects available 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 level of order and then further identified to “morphospecies” as a means of examining preference on a finer scale. The results show that the pitchers captured only a subset of the available insects. The average number of orders captured by each pitcher (1.8 ± 1.0 SD) was lower than that captured by artificial traps (2.8 ± 0.5). Likewise, the average number of morphospecies captured by the pitchers (4.5 ± 4.8) was lower than that captured by the artificial traps (6.8 ± 3.5). These results support the hypothesis that S. alata is selective in its prey capture, but further studies are needed with different methods of measuring the available insects in order to avoid potential bias.