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Full-Text Articles in Life Sciences

Physically, Mentally, And Emotionally Drained, Kaitlin Medina Jan 2024

Physically, Mentally, And Emotionally Drained, Kaitlin Medina

Regis University Student Publications (comprehensive collection)

Hormonal cycles play an essential role in the development and maturation of young boys and girls into men and women. As teenagers enter their late teens and early twenties, their hormonal cycles are primarily responsible for functions related to fertility and hormone production. During this period of time, these men and women are often in their collegiate years. Overall, the college experience is enjoyable for many students, but it can also be a very stressful time due to a difficult class load and the students’ need to balance their academic, social, and personal lives. Recent studies have analyzed the effects …

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Understanding The Environmental And Genetic Influence On Fluctuating Asymmetry And Developmental Instability In Primates, Ashly N. Romero Aug 2023

Understanding The Environmental And Genetic Influence On Fluctuating Asymmetry And Developmental Instability In Primates, Ashly N. Romero

Graduate Theses and Dissertations

This dissertation explored the impact of environmental factors on the development and perpetuation of fluctuating asymmetry (FA) and sought to understand the role evolution may play in the FA exhibited in two primate populations: the free-ranging Cayo Santiago rhesus macaques (Macaca mulatta) and the Southwest National Primate Research Center olive baboons (Papio hamadryas anubis). Demographic, ontogenetic, secular, external, and genetic factors were examined. Specifically, this dissertation investigated FA over all ontogenetic stages, across decades, between sexes, in association with ecological catastrophes, and with tooth pathology to try and tease apart factors that may influence FA and developmental instability. This dissertation …

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The G Protein-Coupled Receptor (Gpcr) Fshr-1 And The Sphk-1 Lipid Kinase Regulate C. Elegans Life- And Healthspans Via A Common Pathway, Ryan Dennis Adkins May 2023

The G Protein-Coupled Receptor (Gpcr) Fshr-1 And The Sphk-1 Lipid Kinase Regulate C. Elegans Life- And Healthspans Via A Common Pathway, Ryan Dennis Adkins

Undergraduate Honors Thesis Collection

Later years of life are often characterized by reduced cognitive function and mobility. One contributor is the cellular accumulation of reactive oxygen species (ROS), but our understanding of how cells respond to ROS to promote health and survival is incomplete. Follicle stimulating hormone receptor-1 (FSHR-1) and sphingosine kinase-1 (SPHK-1) mediate responses to oxidative stress and regulate life history traits in the roundworm Caenorhabditis elegans. The genes encoding both proteins are conserved in humans where they are implicated in stress responses, cell survival and neuronal function. fshr-1 and sphk-1 work together to mediate responses to intestinal oxidative stress in C. elegans. …

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Stress And Parity Among Female Vervet Monkeys (Chlorocebus Pygerythrus) At Two Sites In South Africa, Jo Gansemer Dec 2022

Stress And Parity Among Female Vervet Monkeys (Chlorocebus Pygerythrus) At Two Sites In South Africa, Jo Gansemer

Theses and Dissertations

This thesis examines the hypothesis that in both Soetdoring and !Gariep populations, a femaleSouth African vervet's parity status (nulliparous or parous) affects her physiological stress levels. Vervet monkey ecology and life history are examined to contextualize the relationship between stress and parity. The testing of this hypothesis involves the analysis of hair cortisol concentrations (HCC) of samples from nulliparous and multiparous adult females of the two different South African sites. The HCC was statistically analyzed to look for correlations between stress, parity status, and site. No significant relationship between stress and parity status was found. However, significant relationships were found …

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Alcohol, Stress, And Sex In The Bed Nucleus Of The Stria Terminalis, Nicholas Burski Dec 2022

Alcohol, Stress, And Sex In The Bed Nucleus Of The Stria Terminalis, Nicholas Burski

Electronic Theses and Dissertations

Alcohol use disorder (AUD) costs the U.S. billions of dollars each year and is a leading cause of preventable death. AUD leads to many health complications, and those who suffer from AUD will often have stress and anxiety disorder comorbidities. To better understand this connection between AUD and stress and anxiety disorders, restraint stress (RS) and chronic-intermittent ethanol exposure (CIE) procedures were used on rats to analyze neuroinflammation via ELISA in the infralimbic and prelimbic cortices, and the bed nucleus of the stria terminalis (BNST). Levels of proinflammatory cytokines, TNF-α and IL-1β, were found to be elevated across different tests …

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Patterns Of Evolutionary Conservation And Divergence In The Short-Term Hyposalinity Stress Response Of A Euryhaline Diatom, Skeletonema Marinoi, Kathryn Judy Aug 2022

Patterns Of Evolutionary Conservation And Divergence In The Short-Term Hyposalinity Stress Response Of A Euryhaline Diatom, Skeletonema Marinoi, Kathryn Judy

Graduate Theses and Dissertations

Survival under fluctuating environmental conditions, such as those increasing in frequency and magnitude under environmental change, requires a successful response to stress. Interspecific differences in stress responses may result in differential survival of species, even within a lineage. Diatoms may constitute one such lineage, as salinity tolerance among extant species is diverse, and the observation of frequent historic habitat transitions between marine and freshwater environments indicates that diatoms successfully mitigated (low) salinity stress in the past, followed by adaptation and diversification over evolutionary time scales. To understand to what extent the diatom hypoosmotic stress response consists of conserved and variable …

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Anxiety And Immunity: Affecting The Body And The Mind, Katelynn Dobbs May 2022

Anxiety And Immunity: Affecting The Body And The Mind, Katelynn Dobbs

Theses/Capstones/Creative Projects

Speculations have been made within the scientific community that there is a link between the underlying mechanisms that impact anxiety disorders and immune system disorders. While many correlations between these disorders have been observed through various immune system disorder studies, this subject is still severely under-explored. In order to examine the potential relationship between anxiety disorders and immune system disorders, a survey was conducted and distributed among the student population at the University of Nebraska at Omaha. This survey collected data by asking a variety of questions that pertained to anxiety and immune system disorders diagnoses within the student population …

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Examining Difference In Social Perceptions Between Women Using Hormonal Contraceptives And Naturally Cycling Women, Caroline B. Johnson May 2022

Examining Difference In Social Perceptions Between Women Using Hormonal Contraceptives And Naturally Cycling Women, Caroline B. Johnson

Biological Sciences Undergraduate Honors Theses

The term “stress” refers to a person’s psychological and physiological response to the demands and pressures of the world around them (Farlex, 2021). Past research has shown that stress can have negative side effects on a person’s well-being (Aneshensel et al., 1991; Wunsch et al., 2017; Michie, 2002). Although people experience stress, some people perceive more stress than others. Perceptions are important because the way one understands certain conditions can elicit distinct emotional and physiological responses (Kemeny, 2003). An important factor that has not received a lot of attention is women’s use of hormonal contraceptives. In the United States, 24.4% …

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Analysis Of Test Anxiety In Human Anatomy And Physiology I Students At The University Of Mississippi, Anne Piazza Apr 2022

Analysis Of Test Anxiety In Human Anatomy And Physiology I Students At The University Of Mississippi, Anne Piazza

Honors Theses

Student anxiety, specifically test anxiety, is common hindrance to student performance in various courses including Human Anatomy and Physiology at the University of Mississippi. Through a sequence of three surveys we collected demographic information, anxiety data related to the course, and test anxiety in general We researched factors that could potentially influence student anxiety such as at what point in the semester the student is evaluated, when students feel the most stressed, outcomes on previous evaluations, and perceived outcomes of the course. We also examined what effect the anxiety has on the student such as lowered performance, lowered test scores, …

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Chronic Adolescent Stress As A Predictive Factor For The Risk Of Developing Ptsd-Like Symptoms In Adulthood, Grace K. Young Jan 2022

Chronic Adolescent Stress As A Predictive Factor For The Risk Of Developing Ptsd-Like Symptoms In Adulthood, Grace K. Young

Theses and Dissertations

Post-traumatic stress disorder is a stress and trauma based psychological disorder that is defined by the DSM-IV as an anxiety disorder that affects approximately 7.8% of people in the United States. PTSD is when those who suffer a traumatic event have intense and distressing feelings, emotions, and memories for a prolonged period of time after the event. A prominent feature of PTSD is the impaired ability to properly extinguish a fear response after a dangerous trigger or stressor is no longer present, also known as safety learning. Stressors are threats perceived within the environment that activate a response within the …

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The Regulation Of Stress Steroid Release In Freshwater Turtles, Yoke Tassent Jan 2022

The Regulation Of Stress Steroid Release In Freshwater Turtles, Yoke Tassent

Honors Program Theses

The goal of this study is to characterize the Hypothalamic-Pituitary-Adrenal (HPA) axis regulators of the stress response in a turtle species, the Red-Eared slider, Trachemys scripta elegans and to determine if NPY acts as a secretagogue for adrenal steroids in reptilian species, as it does in mammals. Here, I caught turtles using baited hoop traps. Then, I used pharmacological injections of ACTH (intermediate in HPA axis), dexamethasone (DEX, a synthetic steroid that blocks ACTH release and induces HPA negative feedback), NPY (starvation hormone), and NPY receptor agonists. Each turtle received a single injection upon capture, and I recorded whether adrenal …

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Sex Differences In The Co-Expression Of Estrogen Receptor Alpha With Corticotropin Releasing Factor, Deborah Ariyibi Dec 2021

Sex Differences In The Co-Expression Of Estrogen Receptor Alpha With Corticotropin Releasing Factor, Deborah Ariyibi

Biological Sciences

Women are far more likely to develop anxiety and depression than men. It is believed that the dysregulation of the HPA axis by the binding of corticotropin -releasing factor (CRF) to the corticotropin-releasing factor receptor 1 (CRFR1) contributes to the likelihood of these stress- related disorders. Estrogens acting through Estrogen receptor alpha (ERa) have been shown to increase anxiety production upon activating the HPA axis. In this current study, we explored whether CRF-expressing neurons in various regions of the brain express ERa. The levels of ERa were counted in the bed nucleus of the stria terminalis (BST), the medial preoptic …

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Estrogen Modulation Of Vta Dopamine Neuron Physiology And Behavioral Responsivity To Variable Social Stressors, Mary R. Shanley Sep 2021

Estrogen Modulation Of Vta Dopamine Neuron Physiology And Behavioral Responsivity To Variable Social Stressors, Mary R. Shanley

Dissertations, Theses, and Capstone Projects

The behavioral output of different animals, or even the same animal in different contexts, is remarkably variable in response to the same external stimulus. This behavioral diversity is due to the complex integration of external and internal stimuli, through both neuronal and hormonal signals that selects the best behavioral response. By their nature as long-distance signaling molecules, hormones play a critical role in communicating information about internal states across the organism. Many hormones produced in the periphery target the central nervous system to modulate animal behavior, selecting for behaviors that are appropriate over behaviors that are maladaptive in that specific …

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How Acetylation Regulates Metabolic Enzyme Function During Environmental Shifts, Jared Canonigo May 2021

How Acetylation Regulates Metabolic Enzyme Function During Environmental Shifts, Jared Canonigo

Biological Sciences Undergraduate Honors Theses

Organisms such as Saccharomyces cerevisiae can regulate the mechanisms of proteins through post-translational modification. These modifications play a vital role in functional proteomic activity because they can regulate protein activity, localization, and interaction with other cellular molecules. Such modifications include phosphorylation, methylation, and acetylation. The metabolic mechanisms of yeast became of keen interest to our lab because our lab noticed many stress defense proteins were being acetylated during stress heat shock. Notably, Adh1p and Adh2p showed both an increase and a decrease in acetylation at two lysine residues (K315 and K314) overtime during heat shock respectively, though the exact function …

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Intergenerational Embodiment Of Stress : How The Broader Sociocultural Environment Can Shape Child Growth And Development, Elizabeth A. Holdsworth May 2021

Intergenerational Embodiment Of Stress : How The Broader Sociocultural Environment Can Shape Child Growth And Development, Elizabeth A. Holdsworth

Legacy Theses & Dissertations (2009 - 2024)

Childhood growth has been a means of identifying systemic, material inequalities within populations. The plasticity of growth is responsive to multiple environmental factors, most notably adequate nutrition, but also psychosocial stress. Psychosocial stress can be a function of the social and political economic ecology, reinforcing power hierarchies within societies. This dissertation proposes that childhood growth can also reflect inequality in the distribution of psychosocial stress exposure through mothers’ feelings of a chronically stressful environment conveyed through maternal-infant interactions.

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The Neuroinflammatory Effects Of Chronic Unpredictable Stress On Zebrafish, Danio Rerio, Brandon Stewart Dec 2020

The Neuroinflammatory Effects Of Chronic Unpredictable Stress On Zebrafish, Danio Rerio, Brandon Stewart

Master of Science in Integrative Biology Theses

Stress is a state of threatened homeostasis counteracted by various physiologic and behavioral responses aimed to maintain or restore balance. As such, stress acts as a motivator to perform during the challenges of life to survive. Chronic perturbations to the stress response homeostasis without relief can lead to dysregulation, thus attenuating organ systems and structures and causing significant damage {1]. Individuals who undergo psychological trauma endure an acute and transient experience, which results in minimal functional impairment, but some suffer from a chronic condition called posttraumatic stress disorder (PTSD). Individuals who have PTSD are likely to experience intense stress, …

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Physiological And Behavioral Correlates Of Hif-1 Alpha Protein Levels In The Gulf Killifish, Fundulus Grandis, Jasmine Harris May 2020

Physiological And Behavioral Correlates Of Hif-1 Alpha Protein Levels In The Gulf Killifish, Fundulus Grandis, Jasmine Harris

University of New Orleans Theses and Dissertations

Although the hypoxia-inducible transcription factor (HIF) orchestrates molecular responses to low oxygen, the amount of HIF-1α protein expressed during hypoxia varies among species, individuals, and tissues. This study measured HIF-1α protein levels along with several physiological and behavioral variables in the estuarine fish Fundulus grandis under normoxia (> 7 mg l-1 dissolved oxygen) and hypoxia (1 mg l-1 dissolved oxygen). Fish under hypoxic conditions had higher tissue levels of HIF-1α, hematocrit, blood glucose, blood lactate, frequency of aquatic surface respiration (ASR), and lower activity than normoxic controls. Under hypoxia, HIF-1α abundance in gill was positively correlated with body …

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The Relationship Between Glucocorticoids And The Humoral Immune Response To Mycoplasma Gallisepticum Challenges In Eastern Bluebirds, Joshua Smith May 2020

The Relationship Between Glucocorticoids And The Humoral Immune Response To Mycoplasma Gallisepticum Challenges In Eastern Bluebirds, Joshua Smith

Honors Theses

Numerous studies have examined relationships between adrenal glucocorticoids and the immune system’s ability to fight disease. The relationship can vary, with glucocorticoids having either stimulatory or inhibitory effects. The pathogenic bacterium Mycoplasma gallisepticum (MG) elicits an adaptive immune response in birds, in which B cells produce MG-specific antibodies to fight the infection and prevent reoccurrence. Previous research found that Eastern Bluebirds that produce the most antibodies in response to MG infection also have the highest glucocorticoid levels. This finding led to the current study investigating whether corticosterone, the primary glucocorticoid in birds, stimulates production of antibodies in response to immune …

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Organizational Effects Of Exogenous Corticosterone On Vocal Development In A Wild Parrot, Rory Eggleston May 2020

Organizational Effects Of Exogenous Corticosterone On Vocal Development In A Wild Parrot, Rory Eggleston

Theses and Dissertations

Songbirds learn songs during a plastic phase in vocal development, similar to human vocal babbling. Research has focused on male song learning, a process influenced by gonadal steroids. Like humans, parrots are very plastic vocal learners and both sexes learn vocalizations throughout life. It is unclear how the endocrine system mediates environmental information with developing phenotypes in parrots. Corticosterone (CORT) is a sex-neutral hormone that can affect cognitive development, but its role in vocal development has not been experimentally tested in wild parrots. I quantified vocal babbling from nestling Green-rumped Parrotlets (Forpus passerinus) recorded in Venezuela. Nestlings received oral CORT-oil …

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Tpr-Containing Proteins Control Protein Organization And Homeostasis For The Endoplasmic Reticulum, Jill Bradley-Graham Mar 2020

Tpr-Containing Proteins Control Protein Organization And Homeostasis For The Endoplasmic Reticulum, Jill Bradley-Graham

Doctoral Dissertations

The endoplasmic reticulum (ER) is a complex, multifunctional organelle comprised of a continuous membrane and lumen that is organized into several functional regions. It plays various roles including protein translocation, folding, quality control, secretion, calcium signaling, and lipid biogenesis. Cellular protein homeostasis is maintained by a complicated chaperone network, and the largest functional family within this network consists of proteins containing tetratricopeptide repeats (TPRs). TPRs are well-studied structural motifs that mediate intermolecular protein-protein interactions, supporting interactions with a wide range of ligands or substrates. Nine TPR-containing proteins have been shown to localize to the ER and control protein organization and …

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The Effects Of Prescribed Burning And Microhabitat Type On Ant (Formicidae) Functional Groups And A Survey Of Ants In The Dr. Howard Reynolds Nature Area (A Mixed Grass Prairie), Ashley N. Durr Jan 2020

The Effects Of Prescribed Burning And Microhabitat Type On Ant (Formicidae) Functional Groups And A Survey Of Ants In The Dr. Howard Reynolds Nature Area (A Mixed Grass Prairie), Ashley N. Durr

Master's Theses

This project sought to understand how prescribed burning and microhabitat type impacts Kansas ant functional groups and also whether prescribed burning in different microhabitat types altered the burn’s impact on those functional groups. The Dr. Howard Reynolds Nature Trail, located in Hays, Kansas, was burned in the spring of 2019. The area consists of 2 distinct habitat types: a dry, mixed-grass dominated uphill area and a moist, densely vegetated downhill area. Pitfall trapping was conducted during the summers of the year prior to the burn (2018) and the year following the burn (2019). 15 pitfall traps were spread across each …

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Influence Of Light Availability On Tree Growth, Defense, And Emerald Ash Borer (Agrlius Planipennis) Success In White Fringetree (Chionanthus Virginicus) And Black Ash (Fraxinus Nigra), Michael S. Friedman Jan 2020

Influence Of Light Availability On Tree Growth, Defense, And Emerald Ash Borer (Agrlius Planipennis) Success In White Fringetree (Chionanthus Virginicus) And Black Ash (Fraxinus Nigra), Michael S. Friedman

Browse all Theses and Dissertations

White fringetree is a host for the invasive emerald ash borer (EAB) despite being lower quality than black ash. Observations suggest that host trees grown in full sun are more resistant to EAB than those grown in shade, however chemical defense mechanisms and the impact of environmental stress have not been assessed. We quantified constitutive and induced defenses and other characteristics white fringetree and black ash phloem tissue grown under differential light conditions, and these traits were related to EAB larval performance. White fringetree had significantly lower constitutive and induced activities of defense associated enzymes and lignin but higher phenolic, …

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Undergraduates And Stress, Mahra Crone Dec 2019

Undergraduates And Stress, Mahra Crone

Honors Projects

America is facing a serious mental health crisis, which may be an effect of increased chronic stress. Students, in particular, are vulnerable to this hazard as most face a moderate to extreme amount of stress. The programs which colleges and universities have put into place are outdated. Ineffective treatment of mental health crises leads to disastrous consequences. The present study analyzed the effects of major and grade level on stress level and sources of stress for undergraduate universities at both a large, public university and a small, private college. The author found that a student’s grade level and choice of …

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Analyzing Physiological Stress Response Using Dermal Swabs In Plethodon Montanus, John Tester Aug 2019

Analyzing Physiological Stress Response Using Dermal Swabs In Plethodon Montanus, John Tester

Undergraduate Honors Theses

Upon exposure to environmental stressors, amphibians such as Plethodon montanus will release corticosterone (CORT) thus causing a behavioral and physiological response to cope with the stress. Currently, there are several invasive ways of collecting CORT in salamanders. However, these techniques typically require euthanasia of the organism. We hypothesized that exposure of P. montanus to stressful handling conditions will result in elevations of CORT that can be detected through dermal swabbing. To test this, two experiments were conducted which involved swabbing the dorsal side of the trunk before and immediately after exposing P. montanus to two different environmental stressors. The first …

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The Effects Of Electrofishing On Different Life Stages Of Ozark And Eastern Hellbenders, Stephanie Kay Morrison May 2019

The Effects Of Electrofishing On Different Life Stages Of Ozark And Eastern Hellbenders, Stephanie Kay Morrison

MSU Graduate Theses

Electrofishing, a common method of freshwater fish sampling, has been shown to negatively affect some fish species, but the effects on non-target species, such as hellbenders, have not been well studied. I tested effects of electrofishing on the behavior of several life stages of captivereared Ozark (Cryptobranchus alleganiensis bishopi) and eastern (C. a. alleganiensis) hellbenders. Ozark hellbender eggs were exposed to different voltages in the laboratory, and embryos in higher voltages had higher incidences of twitching during exposures and higher numbers of morphological deformities after exposures. For hatchling Ozark hellbenders, which typically are sedentary, individuals moved more during exposure to …

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Stress And Body Composition Of Juvenile Alligator Snapping Turtles (Macrochelys Temminckii), Brandon Scott Tappmeyer May 2019

Stress And Body Composition Of Juvenile Alligator Snapping Turtles (Macrochelys Temminckii), Brandon Scott Tappmeyer

MSU Graduate Theses

The alligator snapping turtle (Macrochelys temminckii), is a species of conservation concern that is the subject of multiple head-start and reintroduction efforts across its range. In captive propagation programs, producing offspring that are in optimal physiological condition maximizes the likelihood of success after release. The purpose of my study was to compare stress and body composition between one free-ranging reintroduced population and two captive populations. The two captive populations were both housed in southern Oklahoma, but one group was reared indoors whereas the other inhabited outdoor ponds at a national fish hatchery. I used circulating glucocorticoid (corticosterone) concentrations as an …

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Landscape Of Stress: Does Drought Prevail Over Anthropogenic Activity In Influencing Cortisol Levels And Fitness In The Pacific Fisher?, Jennifer R. Kordosky May 2019

Landscape Of Stress: Does Drought Prevail Over Anthropogenic Activity In Influencing Cortisol Levels And Fitness In The Pacific Fisher?, Jennifer R. Kordosky

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fishers (Pekania pennanti) are a species of concern in the Sierra Nevada Mountains of California. Cortisol is a glucocorticoid hormone released to mobilize energy in response to stress and has been used as an indication of an individual’s physiological response to its environment. By collecting samples of fisher hair and measuring an individual’s cortisol, we examined the physiological stress response of the animals to human disturbances (housing density, road density, habitat type, and silvicultural treatements) and drought (tree mortality) in their home ranges. Using AICc model selection, we found that levels of tree mortality within a fisher’s home …

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Detection Of Local Steroidogenic Enzyme Gene Expression In Brown Anoles, Ada Spahija Jan 2018

Detection Of Local Steroidogenic Enzyme Gene Expression In Brown Anoles, Ada Spahija

Honors Program Theses

The endocrine system in vertebrates responds to stress by releasing steroid hormones, mainly glucocorticoids (GC), which increase blood glucose levels to supply key organs and muscles with energy needed for survival. Steroid hormones are synthesized via an enzymatic pathway that converts cholesterol into either GCs, androgens, or estrogens in a step-wise manner. The adrenal cortex is known to produce GCs, but evidence suggests that individual organs can also produce steroid hormones de novo in response to stress. This study aims to quantify gene expression of four steroidogenic enzymes, encoded by CYP19A1, CYP17A1, StAR, and HSD17ß3 genes, via qRT-PCR to determine …

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Endocrine Responses To Repeated Adrenocorticotropic Hormone Administration In Free-Ranging Elephant, Molly Mccormley Jan 2018

Endocrine Responses To Repeated Adrenocorticotropic Hormone Administration In Free-Ranging Elephant, Molly Mccormley

University of the Pacific Theses and Dissertations

Understanding the physiological response of marine mammals to anthropogenic stressors can inform marine ecosystem conservation strategies. Stress stimulates release of glucocorticoid (GC) hormones, which increase energy substrate availability while suppressing energy-intensive processes. Exposure to repeated stressors can potentially affect an animal’s ability to respond to and recover from subsequent challenges. To assess the endocrine response of a marine mammal to repeated stressors, we administered adrenocorticotropic hormone (ACTH) to free-ranging juvenile northern elephant seals (Mirounga angustirostris; n=7) once daily for four days. ACTH administration induced significant, but transient (<24 h) elevation in circulating cortisol levels (p < 0.0001). These increases did not vary in magnitude between the first ACTH challenge on day 1 and the last challenge on day 4. In contrast, aldosterone levels remained elevated above baseline for at least 24 hours after each ACTH injection (p < 0.001), and responses were greater on day 4 than day 1 (p < 0.01). Total triiodothyronine (tT3) levels were decreased on day 4 relative to day 1 (p < 0.01), while reverse triiodothyronine (rT3) concentrations increased relative to baseline on days 1 and 4 (p < 0.001) in response to ACTH, indicating a suppression of thyroid hormone secretion. There was no effect of ACTH on the sex steroid dehydroepiandrosterone (DHEA). These results suggest that elephant seals are able to mount adrenal responses to multiple ACTH challenges. However, repeated stress results in facilitation of aldosterone secretion and suppression of tT3, which may impact osmoregulation and metabolism. We propose that aldosterone and tT3 are informative additional indicators of repeated stress in marine mammals.

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Epigenetic Response To Challenging Environmental Conditions, Marta Robertson Jun 2017

Epigenetic Response To Challenging Environmental Conditions, Marta Robertson

USF Tampa Graduate Theses and Dissertations

The discovery of epigenetic mechanisms has ignited speculation into their role in ecological and evolutionary processes. In particular, the contribution of epigenetic variation to adaptation or phenotypic plasticity that is distinct from genetic variation would be an important addition to existing evolutionary mechanisms. Although the research of epigenetic mechanisms from an ecological and evolutionary (or eco-evolutionary) perspective has been growing, it is still unclear how epigenetic variation might function in natural populations and settings and to what extent it might serve to mediate population response to changing environmental conditions over time. Over the course of my dissertation, I explored the …

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