Life Sciences Commons^™

Oral Microbial Burden Of Periodontal Pathogens Among Orthodontic Patients, David Jolley

UNLV Theses, Dissertations, Professional Papers, and Capstones

Objectives

Many research studies involving orthodontic patients have a natural inclination to focus on changes in levels of cariogenic pathogens after bracket placement, and very few studies examine the role of changes of periodontal pathogens – particularly among adult patients. Interestingly, recent evidence suggests that increased levels of a specific periodontal pathogen, Fusobacterium nucleatum, may elevate risk for development of colon cancer in adults through direct pathways. Based upon this new evidence, the objective of the current study was to screen saliva samples taken from orthodontic patients to determine the prevalence of periodontal pathogens, including F. Nucleatum, T. denticola, and …

Development Of The K-State (Competence) And Mutagenesis In Stressed Bacillus Subtillis Cells, Amanda Kidman

UNLV Theses, Dissertations, Professional Papers, and Capstones

Mutagenesis is central to the evolutionary process. We currently view evolution as a gradual process affecting all cells within a population. However, my project studied an underestimated part of the evolutionary process: mutations generated during stationary phase (caused by nutritional stress or growth arrest) within a subpopulation of cells. I used Bacillus subtilis, a bacterial model for cell growth and differentiation. Stationary-phase cultures of B. subtilis differentiate subpopulations that exhibit different survival strategies including competence, secondary metabolite production, biofilm formation, cannibalism, and endospore formation. The development of competence permits cells to uptake exogenous DNA and incorporate it into their genome. …

An Investigation Of The Testing Effect On Motor Learning, Aaron Leonard Pauls

UNLV Theses, Dissertations, Professional Papers, and Capstones

Optimization of learning processes is the goal many educators strive to achieve with their students. One of the potential methods used towards optimizing this process is what’s known as the testing effect. The testing effect is the improved performance on a retention test as a result of prior testing during some period of practice. Previously, the testing effect was investigated using mostly cognitive tasks such as the learning of a number of words. In this paper, we examine the impact the testing effect has on learning the motor skill of putting. The study used a 2 x 2 mixed design, …

The Effects Of An Inclined And Declined Slope On Backward Locomotion: A Kinematic And Electromyographic Analysis Of Retrowalking, Song Dan Vo

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to investigate the effects of an inclined and declined slopeon kinematic properties and muscle activation magnitudes. This purpose was achieved by using a +10% grade for inclined backward walking (IBW) and -10% grade for declined backwardwalking (DBW) on a treadmill. Eleven participants (24.6 ± 4.1 yrs, 68.5 ± 14.6 kg, 1.7 ± 0.1 m) were recruited from the UNLV student body and were subject to a three day adaptation protocol to allow them to choose a preferred walking speed and to familiarize themselves with such a novel task. Two consecutive practice days included a …

Differential Cbct Analysis Of Collum Angles In Maxillary And Mandibular Anterior Teeth In Patients With Different Malocclusions, Erin Shane Wan Ma

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background: The collum angle is an angular measurement of the difference between the longitudinal axis of the crown and the longitudinal axis of the root. The aim of this study was to determine the mean collum angles for all maxillary and mandibular anterior teeth. In addition, the collum angles of different molar and skeletal classifications were compared for each anterior tooth.

Methods: Based on patient records obtained from the University of Nevada, Las Vegas Department of Orthodontics and Dentofacial Orthopedics, 326 CBCT scans were selected and divided into four molar and skeletal classifications. The patients were divided into Class I, …

Behavioral Reactions To Emotional And Physical Infidelity: An Evolutionary Perspective, Mandy Walsh Walsh

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis examined the effects of sex and type of partner infidelity, including both physical (i.e., sexually involved with another person) and emotional (i.e., emotionally involved with another person) infidelity, on mate abandonment behaviors. Previous research has demonstrated sex differences in emotional responses to infidelity, where men react more negatively to physical infidelity and women react more negatively to emotional infidelity. While various studies have investigated perceived behavioral reactions using imagined scenarios, this study expands current research by utilizing actual retrospective reports. It was hypothesized that males would engage in significantly more mate abandonment behaviors after experiencing a physical infidelity, …

Replicated Risk Nicotinic Cholinergic Receptor Genes For Nicotine Dependence, Lingjun Zuo, Rolando Garcia-Milian, Xiaoyun Guo, Chunlong Zhong, Yunlong Tan, Zhiren Wang, Jijun Wang, Xiaoping Wang, Longli Kang, Lu Lu, Xiangning Chen, Chiang-Shan R. Li, Xingguang Luo

Psychology Faculty Research

It has been hypothesized that the nicotinic acetylcholine receptors (nAChRs) play important roles in nicotine dependence (ND) and influence the number of cigarettes smoked per day (CPD) in smokers. We compiled the associations between nicotinic cholinergic receptor genes (CHRNs) and ND/CPD that were replicated across different studies, reviewed the expression of these risk genes in human/mouse brains, and verified their expression using independent samples of both human and mouse brains. The potential functions of the replicated risk variants were examined using cis-eQTL analysis or predicted using a series of bioinformatics analyses. We found replicated and significant associations for ND/CPD at …

Comparative Genomics Of 9 Novel Paenibacillus Larvae Bacteriophages, Casey Stamereilers, Lucy Leblanc, Diane Yost, Penny S. Amy, Philippos K. Tsourkas

Life Sciences Faculty Research

American Foulbrood Disease, caused by the bacterium Paenibacillus larvae, is one of the most destructive diseases of the honeybee, Apis mellifera. Our group recently published the sequences of 9 new phages with the ability to infect and lyse P. larvae. Here, we characterize the genomes of these P. larvae phages, compare them to each other and to other sequenced P. larvae phages, and putatively identify protein function. The phage genomes are 38–45 kb in size and contain 68–86 genes, most of which appear to be unique to P. larvae phages. We classify P. larvae phages into 2 main clusters and …

The San1 Ubiquitin Ligase Functions Preferentially With Ubiquitin-Conjugating Enzyme Ubc1 During Protein Quality Control, Rebeca Lea Ibarra

UNLV Theses, Dissertations, Professional Papers, and Capstones

Protein quality control (PQC) is a critical process wherein misfolded or damaged proteins are cleared from the cell to maintain protein homeostasis. In eukaryotic cells, the removal of misfolded proteins is primarily accomplished by the ubiquitin-proteasome system (UPS). In the UPS, ubiquitin-conjugating enzymes and ubiquitin ligases append poly-ubiquitin chains onto misfolded protein substrates signaling for their degradation. The kinetics of protein ubiquitylation are paramount since a balance must be achieved between the rapid removal of misfolded proteins versus providing sufficient time for protein chaperones to attempt refolding. To uncover the molecular basis for how PQC substrate ubiquitylation rates are controlled, …

Muscle Activity And Power Output Between Stationary And Outdoor Cycling, Jared Joerger

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study is to compare lower extremity muscle activity and power output during cycling outdoors overground and cycling on a stationary bike trainer at different self-perceived intensity levels. Recreational and competitive cyclists and triathletes, eight male (48.6±8.7 years, 178.9±7.8 cm, 87.1±8.3kg) and three female (40.3±6.8 years, 158±1 cm, 59.6±9.3 kg), signed institutionally approved informed consents and participated in this study. Power data were collected using power instrumented bicycle pedals (PowerTap, Madison, WI) attached to the cyclist’s bicycle. Muscle activity was recorded using wireless electromyography (Delsys, Inc., Natick, MA) sampling at 1926Hz. Participants were tested for maximum voluntary …

Incomplete Denitrification In Thermus Species, Chrisabelle Mefferd

UNLV Theses, Dissertations, Professional Papers, and Capstones

Members the bacterial genus Thermus have been shown to be incomplete denitrifiers, terminating with nitrite or nitrous oxide (N2O). However, the ability to carry out denitrification and the evolution of nitrogen oxide reductase genes in Thermus remains poorly understood. This study tests the hypothesis that incomplete denitrification is common in Thermus and seeks to uncover patterns in the evolution of denitrification pathways in Thermus. Denitrification capacity was determined in a collection of 25 strains representing ten species of Thermus and phylogenetic analysis was performed to determine whether denitrification genes evolved horizontally in Thermus. No strains in this study reduced nitrate …

The Acute Effects Of Different Foam Rolling Timing Durations On Hamstring Flexibility, Chloe Marie Kipnis

UNLV Theses, Dissertations, Professional Papers, and Capstones

The use of a foam roller is growing in popularity as a part of a warm-up in order to prepare for activity. The current research, however, lacks an accepted timing duration for how long an athlete should foam roll prior to activity in order to increase range of motion (ROM). In order to guide clinical practice, it is necessary to establish a standard for how long an athlete should foam roll a muscle group with the goal to increase ROM. Therefore, the purpose of this study was to compare hamstring flexibility changes following a single foam rolling bout, performed for …

The Effect Of Moderate Consumption Of Non-Nutritive Sweeteners On Glucose Tolerance And Body Composition In Rats, Ashley Power Tovar

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Effect of Moderate Consumption Of Non-Nutritive Sweeteners On Glucose Tolerance And Body Composition In Rats

by Ashley Tovar

John C. Young, Ph.D., Examination Committee Chair Professor, Kinesiology and Nutrition Sciences University of Nevada, Las Vegas

Introduction: A comorbidity often seen with obesity is the development of impaired glucose tolerance. Abnormalities in the ability to metabolize glucose can lead to increased risk of developing pre-diabetes and if continued, diabetes mellitus type 2. To combat the effects of excess energy intake on obesity and glucose intolerance, low- energy and non-nutritive sweeteners have been introduced as a replacement for traditional sucrose and …

Water Source Partitioning For Shrubland Transpiration In A Mixed Phreatophytic Plant Community, Amanda Jean Wagner

UNLV Theses, Dissertations, Professional Papers, and Capstones

Groundwater in the basins of east central Nevada (Great Basin Desert, NV) has been permitted for export to southern Nevada. These basins are also vulnerable to changes in climate that could lead to declining recharge. Any decline in groundwater levels no matter the driving force could significantly impact phreatophytes (deep rooted shrubs), which utilize water from both the vadose zone and the capillary fringe to meet plant water needs, to support growth, and for overall health. A reduction in groundwater due to these forces could have a significant impact on the decoupling of phreatophytes from what is normally a reliable …

Examining The Effects Of Body Weight Support And Speed On Physiological Measures And Lower Leg Muscular Activity, Michael Thomas Soucy

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to determine if body weight support or speed influences specific physiological and biomechanical parameters while running at a preferred pace, or variations of preferred pace. Nine participants (age: 28.56 ± 7.88 years, height: 1.68 ± 0.08 cm, mass: 65.70 ± 7.64 kg) who were running a minimum of 10 miles per week (14.67 ± 4.92 miles) were recruited for participation. Participants were asked to sign an institutionally approved informed consent form upon arrival to the lab. After determining preferred running speed at each body weight support condition (no support, 10%, and 20% support), participants …

Biogeochemistry Of A Saline, Alkaline, Terminal Lake Ecosystem In Transition; Walker Lake, Nevada, Katherine Lynn Willever

UNLV Theses, Dissertations, Professional Papers, and Capstones

Walker Lake is a saline, alkaline, terminal lake ecosystem located in west-central Nevada. For over one hundred years, anthropogenic streamflow diversions within the Walker River Basin have ultimately led to little or no water reaching Walker Lake, the basin’s terminus for water flow. These diversions have resulted in a >46 meter decrease in the lake surface altitude and increases in salinity and dissolved salt constituents that have caused the elimination of native fish species. This study examines how the lack of freshwater inflow has altered the physical, chemical, and microbiological structure of Walker Lake during the lake’s ongoing desiccation.

Between …

The Role Of Mfd In Stationary-Phase Oxidative Damage Repair In Bacillus Subtilis, Katelyn E. Porter

UNLV Theses, Dissertations, Professional Papers, and Capstones

Since the 1950’s it has been shown that bacterial cells accumulate mutations even in non- dividing conditions, but how this type of mutation occurs is still highly debated. In Bacillus subtilis, Mfd, a precursor of the nucleotide excision repair (NER) system, mediates the formation of mutations in stationary-phase or non-replicating cells. In growing cells, Mfd recruits repair when RNA polymerase is stalled during transcription; it then recruits proteins from NER to repair damage. Here, we examine the hypothesis that Mfd mediates the formation of mutations by interacting with cellular components that repair reactive oxygen species (ROS), a natural byproduct of …

Stationary-Phase Mutagenesis In Stressed Bacillus Subtilis Cells Operates By Mfd-Dependent Mutagenic Pathways, Martha Gómez-Marroquín, Holly A. Martin, Amber Pepper, Mary E. Girard, Amanda Kidman, Carmen Vallin, Ronald E. Yasbin, Mario Pedraza-Reyes, Eduardo Robleto

Life Sciences Faculty Research

In replication-limited cells of Bacillus subtilis, Mfd is mutagenic at highly transcribed regions, even in the absence of bulky DNA lesions. However, the mechanism leading to increased mutagenesis through Mfd remains currently unknown. Here, we report that Mfd may promote mutagenesis in nutritionally stressed B. subtilis cells by coordinating error-prone repair events mediated by UvrA, MutY and PolI. Using a point-mutated gene conferring leucine auxotrophy as a genetic marker, it was found that the absence of UvrA reduced the Leu+ revertants and that a second mutation in mfd reduced mutagenesis further. Moreover, the mfd and polA mutants presented low but …

Status And Management Of Non-Native Plant Invasion In Three Of The Largest National Parks In The United States, Scott R. Abella, Nicholas A. Fisichelli, Sarah M. Schmid, Teague M. Embrey, Debra Hughson, Jane Cipra

Life Sciences Faculty Research

Globally, invasion by non-native plants threatens resources that nature reserves are designated to protect. We assessed the status of non-native plant invasion on 1,662, 0.1-ha plots in Death Valley National Park, Mojave National Preserve, and Lake Mead National Recreation Area. These parks comprise 2.5 million ha, 23% of the national park land in the contiguous USA. At least one non-native species inhabited 82% of plots. Thirty-one percent of plots contained one non-native species, 30% two, 17% three, and 4% four to ten non-native species. Red brome (Bromus rubens), an ‘ecosystem engineer’ that alters fire regimes, was most widespread, …

Rapidly Restoring Biological Soil Crusts And Ecosystem Functions In A Severely Disturbed Desert Ecosystem, Lindsay P. Chiquoine, Scott R. Abella, Matthew A. Bowker

Life Sciences Faculty Research

Restoring biological soil crusts (biocrusts) in degraded drylands can contribute to recovery of ecosystem functions that have global implications, including erosion resistance and nutrient cycling. To examine techniques for restoring biocrusts, we conducted a replicated, factorial experiment on recently abandoned road surfaces by applying biocrust inoculation (salvaged and stored dry for two years), salvaged topsoil, an abiotic soil amendment (wood shavings), and planting of a dominant perennial shrub (Ambrosia dumosa). Eighteen months after treatments, we measured biocrust abundance and species composition, soil chlorophyll a content and fertility, and soil resistance to erosion. Biocrust addition significantly accelerated biocrust recovery on disturbed …

Post-Concussion Symptom Reporting: Is Gender A Factor In The Adolescent Population? A Systematic Review And Meta-Analysis, Jessica Dunne

UNLV Theses, Dissertations, Professional Papers, and Capstones

The participation in high school athletics among the adolescent population has continued to rise over the past few years. Concussion research has grown and evolved due to an increase in awareness of the seriousness of this injury based on the increase in quantity studies being produced. The research conducted to determine if differences occur between high school athletes and collegiate athletes and if a difference is observed between the genders, has being to grow. Although there has been an increase in research for this injury, the understanding of how this injury affects the adolescent population and how this injury differs …

Assessing Clinical Significance Of The Immediate Post-Concussion Assessment And Cognitive Testing Battery When Comparing Adjusted And Unadjusted Rci Methods For Different Ranges Of Baseline Scores, Ashley N. Figaro

UNLV Theses, Dissertations, Professional Papers, and Capstones

The growing concern revolving around the dangers of sports-related concussions have led to the most recent implementation of neurocognitive (NC) test batteries as a means to objectively determine the presence of a cognitive defect. Whereas any other sports-related injury can be diagnosed with tools such as an x-ray or MRI, a concussion represents a metabolic disturbance that cannot be identified by these diagnostic tools. Many neurocognitive test batteries employ statistical techniques to derive cut off scores in order to represent significant or insignificant changes as compared to individual baseline scores, or pre-established normative values. If an individuals’ post-injury score exceeds …

Cerebellar Transcranial Direct Current Stimulation For Motor Skill Acquisition In A Throwing Task, Austuny Jackson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique in which a very weak electrical current is applied to the scalp to either increase (anodal stimulation) or decrease (cathodal stimulation) the excitability of a selected brain region, most commonly the motor cortex. tDCS is a promising intervention that can modulate cortical excitability, enhance motor learning, and improve motor function in healthy subjects, older adults, stroke patients, Parkinson’s disease, and in other cognitive and motor disorders. Recently, cerebellar transcranial direct current stimulation (c-tDCS) has started to be examined using similar protocols as existing ones used in studies of tDCS …

Investigation Of Sequential Intermittent Pneumatic Compression Effect On Run Performance, Max Evan Jones

UNLV Theses, Dissertations, Professional Papers, and Capstones

The main aim of this study was to determine if IPC after a 5000 m run influences maximal effort 1600 m run performance. A secondary purpose was to determine if the level of IPC pressure used influences run performance. Nine subjects (6 male and 3 female were included in the study; 30 years±5.19 years; Height 173.72cm±8.25; Weight; 72.54±9.97 kg). These subjects were recruited to be in this study via word of mouth or social media advertisement in the Las Vegas area. Participant inclusion criteria was 18- 50 year old apparently healthy, had been running a minimum of 20 miles a …

Physiology And Genetics Of Starvation-Selected Drosophila Melanogaster, Christopher Michael Hardy

UNLV Theses, Dissertations, Professional Papers, and Capstones

In nature, organisms have evolved to survive in stressful environments. This has driven organisms to adopt a wide range of unique adaptations. Investigating the mechanistic basis of these adaptations is an important tool for discovery that has led to major advances in science and medicine.

We study how organisms survive life without food, or starvational stress. Environmental stressors have shaped the quantity and quality of food sources across the globe. This has led to vast differences in the ability of some organisms to tolerate starvation over others. Many researchers have used Drosophila melanogaster as a model to study global patterns …

The Effect Of Gluten On Puberty Onset And Glycemic Response In Female Rats, Bethaney Mclaughlin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: While individuals with gluten sensitivities are instructed to follow a strict gluten-free diet, misinformed concerns over the consumption of gluten products has led to a rise in gluten avoidance diets, without a diagnosis of celiac disease. Gluten-free products, and therefore the diet as a whole, have been found to have twice as much fat, reduced carbohydrates and fiber, and approximately one-third less protein (Miranda 2014). Research on the effects of gluten-free diets on adolescent development is lacking. With recorded nutrient deficiencies in those that abstain from gluten, detrimental effects could be seen in adolescents who are put on non-prescribed …

Hunger Games: The Effects Of Alternate Day Fasting On Food Intake, Body Weight, And Leptin And Ghrelin In Rats, Debra Kirsty Mortel Tacad

UNLV Theses, Dissertations, Professional Papers, and Capstones

PURPOSE: To determine whether a compensatory increase in food intake occurs following a day of fasting, and to determine whether leptin and/or ghrelin levels change in response to ADF compared with ad libitum feeding.

INTRODUCTION: Recently, alternate-day fasting (ADF) has grown in popularity as an alternative to continuous energy restriction (CER) diets as a method for improving health and controlling food intake. Leptin and ghrelin are two hormones implicated in the regulation of food intake and body weight, however their response to ADF is unclear.

METHODS: Male Wistar rats of the same age and weight were randomly assigned to the …

Impacts To Phytoplankton After The Establishment Of Quagga Mussels In Lake Mead, Nevada, Warren Bruce Turkett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Quagga mussels (Dreissena rostriformis bugensis) are an invasive species that were discovered in Lake Mead in January of 2007, and rapidly spread throughout the lake. Quagga mussels are about the size of a fingernail, but are known to clog pipes, damage infrastructure and alter ecosystems. In large numbers, mussels can have a dramatic impact on an ecosystem by reducing the phytoplankton and potentially increasing toxin producing cyanobacteria. This research analyzed data collected from three separate basins in Lake Mead to determine if water quality characteristics that are commonly impacted by invasive mussels have changed. Transparency, chlorophyll-a, phytoplankton and zooplankton samples …

Effectiveness Of Commercially-Available Cosmetic Cleaners On Cosmetics And Cosmetic Brushes, Vanessa Ortiz

UNLV Theses, Dissertations, Professional Papers, and Capstones

The complex nature of skin contributes to the microbial population present on its surface. While normal skin flora is either beneficial or has no effect on the body, there are instances where pathogenic microorganisms are present and can cause infections. Damaged skin is more susceptible to infections from these microbes. Behavioral characteristics, such as the use of cosmetics, can affect the microbial population present on the skin. Staphylococcus aureus is the organism most commonly isolated from cosmetics, and it can be responsible for conjunctivitis, impetigo, boils, and folliculitis.

There are many ways microbial contamination of cosmetics can occur, such as …

Microbial Contamination Of Ice At Food Establishments In Las Vegas, Nevada, Jerry Wills

UNLV Theses, Dissertations, Professional Papers, and Capstones

When food establishments make ice for consumption, it is important to use water free of pathogens and to employ hygienic practices. Freezing can reduce the number of culturable microorganisms present in water but does not eliminate them completely. Coliform bacteria are used as an indicator of water quality and are used to test for fecal contamination. The U.S. Environmental Protection Agency (EPA) establishes standards for drinking water, and has set a goal for zero total coliforms. Another commonly used tool to measure water quality is the heterotrophic plate count (HPC). The EPA limit for HPC is 500 colony forming units …