2020 Abstracts

Wood, Branzen; Oberg, Taylor; Culumber, Michele; Oberg, Craig (Weber State University)
Faculty Advisor: Oberg, Taylor (Utah State University, Nutrition and Food Science); Culumber, Michele (Weber State University, Microbiology); Oberg, Craig (Weber State University, Microbiology)

The unique flavorings and textures of Cheddar cheese are produced by the degradation of the major milk proteins. One of those proteins, casein, is degraded by the enzyme chymosin and a series of peptidases produced by the starter Lactococcus added to the milk. As casein is degraded, several small peptides accumulate. One of these peptides, ß-casein, can have an adverse bitter taste that is non-desirable and considered a defect in Cheddar cheese. The two main starter cultures used industrially in Cheddar cheese making are Lactococcus lactis subsp. lactis and L. lactis subsp. cremoris. L. lactis subsp. cremoris has been used traditionally in Cheddar cheese making, however, L. lactis subsp. lactis ferments more quickly and is becoming more popular in the cheese industry. With the transition creameries have seen a sharp rise in bitterness during production. Our hypothesis was that while closely related, cremoris synthesizes some peptidases that help with ß-casein degradation that lactis does not. Peptidases found in cremoris include PrtP I and II, Pep X, Pep C, Pep A, Pep T, Pep Q, Pep N, Pep V among others. We searched the genomes of both strains using RAST bioinformatic software, and the databases NCBI and UniProt. The peptidases common in cremoris were also found in lactis. We are now trying to determine if the location of the peptidases on the genomes change how they are regulated or produced. Further, we will begin looking into the genome for other, novel, enzymes that might have peptidase activity that influence bitterness.

Shin, Seungwon (Salt Lake Community College)
Faculty Advisor: Seaboch, Melissa (Salt Lake Community College, Anthropology)

The abundance of collared peccaries (Pecari tajucu) is crucial to study because they are a keystone species that plays a large role in their ecosystems. They consume fallen fruits and nuts, disperse seeds, and provide food for predators. Additionally, they are ecosystem engineers altering the landscape for other species. Previous studies have shown that collared peccaries at La Selva Biological Station travel in smaller groups (averaging 10 individuals per group) compared to peccaries at other Neotropical sites. La Selva Biological Station is located in northeastern Costa Rica and it consists of both primary and secondary (i.e. degraded) forests surrounded on three sides by farmland. Due to the general decline of mammals in degraded habitats, I predicted that the average group size of collared peccaries at La Selva will be even smaller than previously reported. I collected data at La Selva Biological Station for two weeks in May 2019. I used three census methods: total count sampling (counting all the species in a certain area), line transect sampling (counting all the species I see when I walk through a trail), and point sampling (standing at selected viewpoints and recording the species visible from that location). I observed 39 peccaries in 17 separate sightings. Group size ranged from 1 to 7 peccaries with an average of 2.3 peccaries per group. Eight sightings (20%) were of single peccaries. My hypothesis that peccary group size would be smaller than 10 individuals was supported. Some limitations of the study were low visibility due to the dense forest and the dispersed social organization of peccary individuals within the group. Both of these factors would underestimate the actual group size of collared peccaries. Nevertheless, the results support previous findings that peccary group size at La Selva are smaller than at other Neotropical sites.

Hirschi-Forster, Jeanallie; Mendoza, Matthew; Van Oene; Nicholas ; Payton, Jullian (Weber State University)
Faculty Advisor: Clark, Daniel (Science, Microbiology)

The purpose of this research is to obtain quantitative data about possible sources for Salmonella contamination including tributaries to the Great Salt Lake, namely, the Jordan River, Weber River, and Bear River in Utah. We will also analyze specific water and soil sources near poultry farms for possible contamination. In recent studies, there is a greater number of produce items that have been found to contribute to Salmonella outbreaks. Contaminated water used for irrigation of these crops has been implicated as the causative agent for food contamination.

Bacteria found in these waterways are enriched using selective and differential media. This means, the media provides Salmonella species with required nutrients to grow effectively while differential media inhibits the growth of non-Salmonella species. The enrichment media that is used during this process is 3 X Tryptic Soy Broth and Gram-Negative broth. Gram negative broth is used as an enrichment step, but also selective in that it inhibits growth of other organisms. The two types of differential media would be XLT4 and MSRV. Salmonella is a motile bacterium and thus branches out from its original location of inoculation. This creates a halo-like growth pattern that makes it possible to differentiate Salmonella on MSRV plates. Once Salmonella is confirmed through the MSRV and XLT4 media, sequencing of its two CRISPR loci is completed. These two chromosomal regions have been shown to be distinct in different serovars, and as such, they can be used to distinct what subspecies is present in the sample.

Hirschi, Blake; Pickett, Brad; Thompson, Jared; Telford, Mady; Berges, Bradford (Brigham Young University)
Faculty Advisor: Berges, Brad (Life Sciences, Microbiology and Molecular Biology)

Staphylococcus aureus (S. aureus) is a commensal bacterium commonly found amongst livestock and near 30% of humans' nostrils. However, through acquisition of certain genes S. aureus may develop antibiotic resistance such as in methicillin-resistant Staphylococcus aureus (MRSA). One hypothesized component lending to acquisition of genetic resistance in S. aureus is the synthesis of colony biofilms. Biofilms are comprised of a variety of substances including secreted polysaccharides, protein and even extracellular DNA. Our work postulates that extracellular DNA-based biofilms will transfer genes for antibiotic resistance at a higher rate than in polysaccharide/protein biofilms. Through employment of polymerase chain reaction (PCR), we aim to characterize a wide sample of methicillin-susceptible S. aureus (MSSA) human associated strains and MRSA livestock associated strains for multiple antibiotic resistances. Co-inoculating pairs of human associated and livestock associated strains, each lacking the other's resistance genes, will provide an environment wherein biofilm-mediated gene transfer may occur. Further pairing based on biofilm composition (DNA or polysaccharide/protein) will yield data concerning which biofilm facilitates gene transfer more efficiently. Subsequent genotyping will confirm whether resulting isolates acquired new antibiotic resistance through biofilm-mediated transfer, thus increasing pathogenicity.

Tuttle, Jared; Payne, Andrew; Obray, J Daniel; Steffensen, Scott (Brigham Young University)
Faculty Advisor: Steffensen, Scott (Family, Home, and Social Sciences; Psychology)

A subpopulation of ventral tegmental area (VTA) GABA neurons express connexin-36 (Cx36) gap junctions (GJs). Activation of GJ-mediated electrical coupling between VTA GABA neurons supports brain stimulation reward and alcohol reward is lowered in Cx36 KO mice due to a hyper-dopamine (DA) state. The aim of this study was to further evaluate the role of a subpopulation of Cx36+ VTA GABA neurons in alcohol reward and dependence. To accomplish this study, we customized a Gq-coupled Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) viral vector to only express in Cx36+ neurons (AAV8.hCx36.hM3D(Gq)-mCherry.WPRE.rBG) in the VTA. The hM3Dq viral vector was infused into male CD-1 GAD GFP mice and male Wistar rats. The animals were then given 10-14 days to recover prior to experimentation. A control virus (AAV9.CB7.CI.mCherry.WPRE.rBG) was used for comparison. We implemented standard cell-attached mode electrophysiology to evaluate the effects of clozapine-n-oxide (CNO; the ligand for DREADDs) on VTA GABA and DA neuronal activity. We found a robust enhancement of VTA GABA neuron firing rate in hM3Dq+ neurons with 20 _M CNO ex vivo. Surprisingly, while investigating CNO effects on VTA DA neuron firing rate, we found that CNO activation of hM3Dq+ VTA GABA neurons increased DA neuron activity, suggesting that Cx36+ VTA GABA neurons indirectly modulate local VTA DA neurons. Intraperitoneal CNO (3 mg/kg) also enhanced the firing rate of VTA GABA neurons in vivo. Administration of CNO reduced ethanol consumption (drink-in-the-dark paradigm) in both ethanol naïve and ethanol dependent hM3Dq-injected mice as compared to controls, suggesting that activation of Cx36+ neurons in the VTA is enough to block ethanol consumption in both naïve and dependent animals. Taken together, these findings support previous studies indicating that enhanced electrical coupling between VTA GABA neurons is rewarding and promotes reward and lowers the hedonic value of ethanol.

Aitken, Talon; Jensen, Daelin; Baxter, Melanie (Brigham Young University)
Faculty Advisor: Tessem, Jeffrey (Brigham Young University, NDFS)

Diabetes Mellitus, a condition characterized by hyperglycemia resulting from defects in insulin secretion or effectiveness, affects over 8.5% of the adult US population. Both type one and type two diabetes have the common characteristic of a decrease of functional beta-cell mass from the islets of Langerhans, located within the pancreas. The upregulation of genes known to induce beta-cell growth and proliferation results in an increase of functional beta-cell mass in young cells but not in their aged counterparts. This age-related occurrence - under nonpathologic conditions — is poorly understood. For this study, the morphological differences between young islets and aged islets are studied to provide insight as to the reason behind this refractory behavior. Immunostaining methods show significant contrast been percentages of insulin-positive beta-cell area in the pancreata of young vs. old-aged rats.

Miller, Jacob; Cheung, Aaron; Novilla, Kirsten; Crandall, Aliceann (Brigham Young University)
Faculty Advisor: Crandall, Aliceann (Life Sciences, Public Health)

Existing literature demonstrates a strong relationship between childhood experiences and adult health outcomes. The Differential Susceptibility to Environment Theory suggests that there are several factors, including personality and physiology, that effect a child's sensitivity to adverse and advantageous experiences. A sample of 246 adults (ages 19-57) were asked questions about extroverted personality characteristics, adverse and advantageous childhood experiences, and several measures of adult health, including executive functioning, perceived stress levels, depression, and past smoking habits. The sample was then stratified based on level of extroversion scores with the top quartile being labeled as "extroverts", the bottom quartile as "introverts", and those in between as "ambiverts". Regression analyses were then used to assess the relationship between childhood experiences and each adult health outcome. The results of the study showed that the extroverted individuals experienced more positive health outcomes after more advantageous childhood experiences, as well as decreases in adult health outcomes after more adverse childhood experiences. These results suggest that extroverts more than introverts are more sensitivity to environmental influences in childhood. More research is needed to understand the neurobiological mechanisms that increase environmental sensitivity among extroverts.

Burgoyne, Jake; Leavitt, Steve (Brigham Young University)
Faculty Advisor: Leavitt, Steve (Life Sciences, Biology)

In show caves, artificially lighting is intended to highlight intricate cave formations for visitors. However, as an unintended consequence, artificial lighting promotes the growth of diverse biofilm communities termed Lampenflora that gain their energy from these novel light sources. Lampenflora, which generally consist of algae and cyanobacteria, discolor formations and introduce novel ecological interactions in simple cave ecosystems. Lampenflora communities have been understudied mainly due to technological limitations and difficult accessibility. However, by characterizing these communities, we can better monitor their impact and develop effective strategies for their removal. Using metagenomic high-throughput sequencing, this research provides the first molecular-based perspective into lampenflora diversity in cave systems in the Great Basin. The data collected, generated, and analyzed is vital in understanding Lampenflora biodiversity and how these communities develop. Furthermore, it offers ecologists a novel perspective on the use molecular detection to understand biodiversity within cave systems.

Murley, Jordan; Stockard, Alyssa; Payne, Andrew; Steffensen, Scott (Brigham Young University)
Faculty Advisor: Steffensen, Scott (Family, Home, and Social Sciences; Psychology)

Brain-derived neurotrophic factor (BDNF) is implicated in varied physiological processes. Its main receptor in the central nervous system is tyrosine receptor kinase B (TrkB), and the main ligand for TrkB in the central nervous system is BDNF. It has been shown previously that activating TrkB can cause a downregulation of the chloride-exporting potassium chloride cotransporter 2 (KCC2), presumably resulting in a decreased chloride gradient. It is hypothesized that this down-regulation, caused by an increase in BDNF levels, creates hyperexcitable GABA neurons in the ventral tegmental area (VTA) due to a reduced efficacy of inhibitory currents. Here we investigate this mechanism of adaptation in the context of chronic alcohol exposure. We demonstrate that BDNF levels are elevated in the VTA during withdrawal from chronic alcohol exposure. We also observe that blocking TrkB activity decreases alcohol seeking behavior. Further, we investigate the expression patterns of KCC2 in connection with chronic alcohol administration. Additional work is underway to validate this mechanism and further elucidate its putative role in alcohol dependence.

Diaz, Paula; Baptista, Gabriella; Obray, J Daniel; Steffensen, Scott (Brigham Young University)
Faculty Advisor: Steffensen, Scott (Family, Home, and Social Sciences; Psychology)

The prevailing view is that enhancement of dopamine (DA) transmission in the mesolimbic DA system underlies the rewarding properties of alcohol. The aim of the present study was to help reconcile the relative insensitivity of DA neurons to ethanol in vitro (EC50 = 96 mM) with the sensitivity of DA neurons in vivo (EC50 = 3 mM). To do this we investigated the role of peripheral dopamine 2 receptor (D2R) mediated neuroimmune responses in ethanol enhancement of DA release in the NAc and ethanol reward. We found that systemic administration of ethanol (0.5-4.0 g/kg) markedly enhanced DA release in the NAc while pretreatment with a peripheral-only D2 receptor (D2R) antagonist blocked these effects. A place conditioning paradigm was used to test rats for ethanol preference. Administration of a peripheral D2R antagonist before ethanol conditioning trials was found to prevent acquisition of ethanol conditioned place preference. Finally, ethanol suppression of locomotor activity in rats was attenuated by domperidone pre-administration. Domperidone pre-administration did not affect ethanol impairment of motor coordination. These findings suggest that ethanol enhancement of DA release, intoxication, and ethanol reward are all mediated, at least in part, by a peripheral mechanism involving D2Rs. These results challenge the dogma regarding direct ethanol actions on mesolimbic DA transmission and potentially provides novel pharmacological targets for the treatment of alcohol use disorder.

Stehn, Christopher; Colman, Howard; Boucher, Kenneth; Grossman, Allie H; Holmen, Sheri L (University of Utah)
Faculty Advisor: Holmen, Sheri (University of Utah, Surgery)

Despite therapeutic advances in the treatment of melanoma, development of brain metastases continues to be a major cause of treatment failure. Prognosis for patients with brain metastases is exceedingly poor, therefore the development of sensitive and specific biomarkers to predict which melanoma patients are at highest risk for disease progression are needed. To accomplish this goal, we developed a novel combined molecular/clinical/pathologic predictor of brain metastasis risk. We first analyzed multiple gene expression datasets including The Cancer Genome Atlas (TCGA; n = 437) and an independent series from the European Genome-Phenome Archive (n = 183) and identified a list of 60 consensus genes that is robustly predictive of development of melanoma brain metastases (p < 0.05; FDR 5%). Next, we performed a similar analysis of association of miRNAs and melanoma brain metastasis risk which identified a set of miRNAs with significant predictive power. An optimized combined set of 15 mRNA and miRNA markers was a better predictor of brain metastasis risk than either mRNA or miRNA list alone when applied to the TCGA data set. The combined predictor was most sensitive in separating patients with no metastases from those with either brain metastases or systemic metastases. Current efforts are focused on optimizing miRNA and mRNA separation of patients specifically with brain metastases from those with other metastases using a machine learning linear classifier, and with integrating the expression classifier with other clinical and pathologic predictive factors including: age, stage, thickness, location, histology, ulceration, and gender. The sensitivity and specificity of the resulting clinical/molecular predictor will be validated in an independent retrospective patient dataset, and subsequently implemented in a prospective brain metastasis screening trial to determine real-world utility of this approach in preparation for prospective brain metastasis adjuvant/chemoprevention trials utilizing both immunotherapy and targeted therapy approaches.

Villanueva,Xitlalli; Berthelemy Nicole (Weber State University)
Faculty Advisor: Berthelemy, Nicole (Weber State University, Zoology)

Introduction: Mercury, originating from mining and industrial activity, has been accumulating in the Great Salt Lake water and has contaminated its food web. Some of the mercury chloride (HgCl) is transformed by benthic bacteria to the more toxic monomethyl mercury (MeHg). While the effect of HgCl on the brine shrimp Artemia franciscana has been described, little is known about the effects of MeHG on this shrimp, except that it is more toxic. We correlated the tissue mercury concentrations to the amount of mercury present in the sea-water (SW). We also tested the ability of the shrimp to depurate mercury accumulated in the tissues.
Results: - Adult Artemia survived at least one week when exposed to concentrations ranging from 10-9 to 10-5g/L HgCl or MeHg. Shrimp exposed to 10-4g/L HgCl or MeHg died within two days.
Fertility was influenced by mercury exposure. The number of offspring per brood produced by females exposed to 10-6g/L or less HgCl was around 150, significantly higher than the average 80 offspring per brood produced by females exposed to 10-6g/L MeHg. When exposed to 10-5g/l HgCl and MeHg, the females brood size was 47 and 24, respectively.
- Artemia is able to maintain low level of tissue mercury, up to exposure to 10-6g/L HgCl and 10-7 g/L for MeHg. Exposure to higher mercury concentrations leads to much higher mercury levels, about 35 ppm HgCl for SW reaching 10-5g/L and 300 ppm with exposure to 10-4 MeHg.
Discussion: While both HgCl and MeHg are lethal to the shrimp, after a few days exposure, at concentration higher than 10-6 g/L, MeHg has a stronger effect on fertility, with brood size near half the size. Also, MeHg, the organic form of mercury, is accumulated in much higher level than the inorganic form. The organic form has a better ability to cross cell membranes. Since the mercury levels in the Great Salt Lake reach 55 ng/L (= 0.055 10-6g/L) and 30 ng/L (0.03 10-6 g/L) for HgCl and MeHG, respectively, the brine shrimp population is likely not affected by this pollutant.
Conclusion: Mercury has a strong effect on Artemia metabolism. We will study, next, the shrimp response to the oxidative stress induced by the mercury exposure.

Stevens, Andrew; Hicks, Joseph; Savage, Ryland; Bailey, Bruce (Brigham Young University)
Faculty Advisor: Bailey, Bruce (Life Sciences, Exercise Science)

Purpose: This study examined the effect that differing exercise intensities have on subjective ratings of vitality both immediately following the condition and after 60 minutes of intense cognitive testing.
Methods: These findings come as a secondary analysis of a larger randomized crossover study that examined the effects of differing exercise intensities on cognitive performance. We recruited 228 men and women in roughly equal numbers to participate in the study. Each participant reported to the study lab four times one week apart. During the first day the participants ran a VO2 max test to establish pacing and baseline values. During the next three visits the participant completed a subjective vitality questionnaire before exercise, after 40 minutes of exercise or watching a video, and after 60 minutes of cognitive testing. The exercise conditions of vigorous (70% VO2 Max), moderate (35% VO2 Max) and sedentary activity (watching a video) were randomly assigned each week.
Results: The vitality rating before exercise was not significantly different between the three conditions with a mean rating of 19.9 ± 8.6 cm. After the sedentary condition, subjective ratings of vitality decreased from 19.9 cm to 12.5 cm after the condition and increased to 15.0 cm after the cognitive testing, remaining below pre-exercise values. After the moderate exercise condition, vitality did not change significantly after exercise (20.2 cm to 21.0 cm) but was lower following the cognitive tasks (15.9 cm). Vitality was slightly elevated following the vigorous exercise condition (19.8 cm to 21.3 cm) but went down after the cognitive tasks (17.1 cm). Vitality ratings did not differ significantly between exercise conditions at any time. The sedentary condition was lower than both exercise conditions after the 40-min intervention (p<0.001) and was lower than the vigorous exercise condition after the cognitive tasks (p<0.001).
Conclusion: Sedentary tasks may reduce subjective feelings of energy and vitality and this subjective evaluation remains suppressed after a period of cognitive exertion. Feelings of vitality and energy remain similar before and after exercise (vigorous or moderate) but then reduce after cognitive exertion. Vigorous exercise may be slightly beneficial for subjective feeling of vitality after exercise and following extended cognitive exertion.

Mueller, Kaeli; Kaitlyn, Golden; Johnson, J.B. (Brigham Young University)
Faculty Advisor: Johnson, Jerry (Brigham Young University, College of Life Sciences);

Human-induced changes to the environment are causing declines in many of the world's species. Studying model organisms, such as Poeciilidae fishes, can provide crucial information about a variety of other species (Johnson & Bagley, 2011). Alfaro, a monophyletic genus within the family Poeciilidae (Bagley & Johnson, 2014), has the potential to become an exemplary model species. There is currently much scientific knowledge about the two distinct reproductive tactics of Poeciliid males. However, studies about the presence of this trait are lacking for Alfaro. Therefore, I propose adding to the current knowledge about Alfaro cultratus by researching the presence of two distinct sets of traits that accompany different male reproductive tactics. The hypothesis is that male Alfaro will show similar physical characteristics to other Poeciliids, but that these traits will not differ across varying habitats. Measurements of deceased Alfaro specimens will be analyzed to identify differences in physical traits. This will be followed by a live experiment, in which the male size differential is expected to mirror that of the deceased specimens. This research will produce novel information about Alfaro cultratus because its life history strategies have yet to be described. Many intriguing evolution questions could follow.

References:

Bagley, J. C., & Johnson, J. B. (2014). Testing for shared biogeographic history in the lower Central American freshwater fish assemblage using comparative phylogeography: Concerted, independent, or multiple evolutionary responses? Ecology and Evolution, 4(9), 1686—1705.

Johnson, J. B., & Bagley, J. C. (2011). Ecology and Evolution of Poeciliid Fishes, Chapter 4, Ecological drivers of life-history divergence.

Chou, Audrey; Duffy, Alexandra; Johnson, Jerald (Brigham Young University)
Faculty Advisor: Johnson, Jerald (Brigham Young University, Biology)

Upon injury, fish release chemicals that cause fear and a dramatic change in behavior in nearby members of the species. Chemical alarm cues are released from injured epidermal tissue and provide an early warning signal for individuals to detect the presence of an active predator, and potentially increase the chances of individual survival. This research project investigates the conservation of alarm cue recognition and response across species boundaries by measuring the behavioral response of Brachyrhaphis rhabdophora to the alarm cues from five different species. Since these species will be of known phylogenetic relatedness, we will determine conservation of alarm cue response as a function of phylogenetic distance. I will also discuss the method of quantifying behavioral response through the use of a two-choice flume tank to measure both changes in activity and spatial avoidance upon alarm cue exposure.

Jones, Dalton (Weber State University)
Faculty Advisor: Schramm, Katharina (Science, Botany)

Tomatoes (Solanum lycopersicum) are an important agricultural crop around the world. In order to produce food with less impact on the environment, many researchers are looking to utilize natural systems to maximize production with minimal inputs. Maximizing tomato defenses is one possible way to increase productivity. Tomatoes produce both physical and chemical defenses in response to the stress. Increasing the number of trichomes on the plant is a physical means of deterring insects from eating the plant. Trichomes come in two forms glandular trichomes and non-glandular trichomes. The non-glandular trichomes are strictly a physical defense while the glandular trichomes produce chemical defensive compounds against a wide variety of insects. Most land plants can form a symbiosis with arbuscular mycorrhizal fungi (AMF). This symbiosis has been shown to increase nutrient supply, decrease drought stress, and prime plant defenses, all increasing a plant's ability to withstand herbivory stress better. This study examines the response of trichomes and the number of chemical defenses after insect herbivory has occurred with the additional support of the AMF symbiosis. Treatments were exposed to Manduca sexta to stimulate trichome and chemical production. The extracted leaves were analyzed via gas chromatography to examine the make-up of the tomato's chemical defenses. The growth rates of M. sexta were recorded to examine the effects of tomato's chemical defenses after feeding the insects the induced tomato leaves. Measuring trichome density quantifies the change in physical defenses. The addition of the AMF increased the plant defenses, both the number of trichomes present on the plants and the quantity of the chemical defenses. Insects feeding on plants with increased defenses were also shown to have decreased growth. This study shows an alternative strategy for the use of commercial pesticides, lessening the impact of tomato crops on the ecosystem.

Brunetti, Bryce; Escarate, Ashley; Conway, Matthew; Slezak, Cyrill; Kopp, Olga (Utah Valley University)
Faculty Advisor: Kopp, Olga (Utah Valley University, Biology); Slezak, Cyrill (Utah Valley University, Physics)

Purpose:
This study evaluates the effect of electrohydraulic shockwaves on Staphylococcus aureus biofilms. This system could be a great alternative to the use of antibiotics, and potentially life-saving technology that could save billions of dollars.

Background:
The rise of antibiotic-resistant bacteria is a global threat. Staphylococcus aureus is typically harmless, but this gram-positive species has become highly resistant and extremely pathogenic. Strains like MRSA and VRSA have the highest rate of drug resistance and are the leading cause of chronic bacterial infections via bacterial biofilms on medical devices. Biofilms are an aggregation of microbes that excrete an extracellular matrix providing an ideal environment for gene exchange and quorum sensing. Their complexity hinders the diffusion of antimicrobials. A proposed method to prevent device-associated infection is shockwave sterilization and therapy. A shockwave is a high-energy wave causing a sudden change in temperature, pressure and density in the medium. This study investigates the potential disruption of bacterial biofilms by electrohydraulic shockwaves.

Methods:
E. coli and S. aureus biofilms were grown on polystyrene plates. Biofilms were treated with shockwaves (0.19mJ/mm2, 300 pulses, 3 Hz) in a water bath and compared with those treated with Vancomycin. Cell viability was determined through XTT/menadione absorbance and specific biofilm formation through crystal violet absorbance.

Results:
Current testing has shown that electrohydraulic shockwaves have a bacteriostatic effect on biofilms. Other finding show potential for shockwaves to increase bacterial susceptibility to lower levels of antibiotics.

Conclusions:
Device-associated infections are a serious threat to patients' health. The diminishing effectiveness of antibiotics in treating and preventing infections along with evolution of mass resistance in bacteria have given rise to the term "post-antibiotic era." The better understanding of electrohydraulic shockwaves bacteriostatic effect could lead to more effective treatments for antibiotic resistant bacteria such as S. aureus.

Savage, Ryland; Stevens, Andrew; Hicks, Joseph (Brigham Young University)
Faculty Advisor: Bailey, Bruce (Brigham Young University, Exercise Science)

Purpose: This study examined the effect of different intensities of exercise on subjective feelings of fatigue both immediately following exercise and after 60 minutes of intense cognitive testing in men and woman.
Methods: These results come from a secondary analysis of a larger randomized crossover study examining the different levels of exercise intensity on cognitive performance. We recruited 228 men and woman to participate in the study. Each participant was tested after three exercise conditions: moderate (35% VO2 max), vigorous (70% VO2 max), and sedentary (no exercise). Each exercise condition was randomized and each test was separated by one week. After each 40-minute exercise condition, we administered a visual analog scale to evaluate subjective feelings of fatigue. This assessment of fatigue was delivered before treatment, immediately after treatment and then again after a variety of cognitive tasks were performed for the duration of one hour.
Results: For the sedentary condition, feelings of fatigue increased after the 40-minute intervention (p<0.001) and decreased after 60 minutes of cognitive work but remaining elevated compared to baseline (p<0.01). For the moderate condition, feelings of fatigue did not change immediately after exercise (p=0.063) but then increased after 60 minutes of cognitive work (p<0.001). For vigorous condition, feelings of fatigue increased after exercise(p<0.001) and remained elevated after performing the cognitive tasks (p=0.163). Following the 40-minute intervention, fatigue was highest after the sedentary condition, followed by the vigorous condition and did not change after completion of the moderate condition. Following 60 minutes of cognitive work, fatigue was highest in the vigorous condition (p<0.001) and did not differ between the sedentary and moderate conditions (p=0.063).
Conclusion: The results of this study show that moderate exercise has no significant impact on feelings of fatigue but exercise at a higher intensity and being sedentary increase fatigue. Doing cognitive work increases fatigue if exercise precedes the tasks but being sedentary beforehand decreases feelings of fatigue during cognitive tasks. This suggests cognitive work is usually draining, but if performed after sedentary or low activity states such as watching TV, cognitive work will be invigorating and help feel more alert.