Biology Commons^™

Effects Of Tourist Feeding On The Gut Microbiome And Ecophysiology Of Endangered Northern Bahamian Rock Iguana (Cyclura Cychlura), Erin Lucy Lewis

All Graduate Theses and Dissertations, Fall 2023 to Present

The lifespan and reproduction of an animal depends on maintaining a healthy physiology. The proportion of individuals that survive to an age at which procreation can occur is important to long-term stability of populations and contributes to species survival. Health in an animal is measured in a variety of ways, including through monitoring of the body’s physiological systems, as well as its ability to respond to invading pathogens, and through the different types of bacteria present in the gut. Relationships among those different health metrics have been discovered in recent years and have been found to play important roles in …

Morphological Variation Of Lingual Glands In Wild American Alligator (Alligator Mississippiensis) Populations, Benjamin Angalet

Master's Theses

American alligators (Alligator mississippiensis) inhabit diverse aquatic ecosystems including freshwater wetlands, swamps, and estuarine rivers. As apex predators, their physiological resilience has implications for ecosystem stability and long-term conservation. With projected sea-level rise and increasing saltwater intrusion into coastal freshwater habitats, understanding the osmoregulatory capacity of alligators is increasingly important. Unlike marine-tolerant crocodilians such as the saltwater crocodile (Crocodylus porosus), which possess specialized salt-secreting lingual glands in addition to renal and cloacal mechanisms, the morphology and physiological significance of lingual glands in wild American alligators remain poorly understood. This study examined lingual gland morphology and plasma …

Love In The Fast Lane: Rapid Physiological Senescence At Sexual Maturity In Male Colorado Brown Tarantulas (Aphonopelma Hentzi), Spencer Poscente

Master's Theses and Doctoral Dissertations

Sexual dimorphism in longevity represents a striking example of natural selection favoring reproductive success over survival: in Colorado brown tarantulas (Aphonopelma hentzi), females live over two decades while males survive just months after reaching sexual maturity. I collected sexually mature males at three time points (August, September, October) across two years and quantified metabolic rates, locomotor performance, and survival under controlled laboratory conditions. This thesis comprises two articles examining complementary dimensions of that decline: metabolic senescence and locomotor performance. Open-flow respirometry revealed significant seasonal shifts: minimum metabolic rate increased through October, and metabolic scope peaked in September before declining. Survival …

Coral Holobiont Lipidome Response To Global Change, Lauren Zane

Open Access Dissertations

Climate change is fundamentally restructuring macro-scale marine ecosystem structure and function by altering microscale metabolic processes and patterns of energy allocation. Scleractinian corals, as major ecosystem engineers, play outsized roles in ecosystem structure and function. They also occupy diverse habitats that differ in temperature regimes, light environments, hydrodynamics, and other environmental conditions, exposing corals to substantial spatial variation in stress and resource availability. Their fragile nutritional symbiosis with algal endosymbionts helps them navigate these environmental variations, but are also highly sensitive to environmental stress, particularly the timing and magnitude of water temperature changes. As pressure from environmental changes increases, the …

Morphological And Transcriptional Responses Of Mammalian Cells To Glucose Stress, Cassandra Burke

UNLV Theses, Dissertations, Professional Papers, and Capstones

Organismal cells encounter varying conditions, including daily and potentially seasonal fluctuations in available glucose. While some species tightly regulate circulating glucose levels, others tolerate extreme fluctuations, such as frugivorous bats experiencing post-prandial hyperglycemia and hibernating mammals maintaining stable glucose through torpor and hibernation. To investigate how these species-specific strategies influence cellular responses to glucose perturbation, primary dermal fibroblasts from nine mammals – humans, rats, Egyptian fruit bats, brown bear, 13-lined ground squirrel, little brown bat, gelada, honey badger, and Bactrian camel – were exposed to hypoglycemic (2.5mM), baseline (8mM), or hyperglycemic (30mM) treatment. Cell morphology was evaluated using Cell Painting, …

Light, Symbiosis, And The Biology Of Corals, Taylor R. Lindsay

Open Access Dissertations

Light is critical for the survival of most shallow water scleractinian corals. Corals are mixotrophs, acquiring energy via both feeding on water column plankton and photosynthesis via a symbiotic relationship with dinoflagellates living within their tissues. Corals rely heavily on photosynthetically derived metabolites through this symbiotic relationship, intrinsically linking their biology to light availability. Corals are known to modulate their biology to maximize light capture. However, there is a limited understanding of the interaction between morphology, physiology, and energetic strategy, as well as how light may affect these relationships. In Chapter 1, we quantified the morphology, physiology and energetic …

Effects Of Diet Composition On Physical Parameters In Danio Rerio, Isabella Hemphill

Williams Honors College, Honors Research Projects

With the use of zebrafish as a common model organism for human health, the reduction of confounding variables in their care is key. Many commercialized zebrafish diets are available for purchase, but each one consists of a different ratio of these crucial macronutrients. This study aimed to determine the effects long-term diets high in one macronutrient would have on the morphometrics, heart, liver, and protein content of zebrafish. Four diets were fed over a period of almost two years- high lipid, high carb, high protein, and a control diet. The control diet was the standard feed used in this lab, …

Feeling Blue: The Effects Of Blue Light Exposure On Reproduction And Physiology In Drosophila Melanogaster, Laura Hampel

Theses and Dissertations (Comprehensive)

Blue light, the wavelengths ranging from ~400-500 nm, is emitted from the sun and more recently, by artificial lights including those in technology. In humans, prolonged exposure to blue light has been consistently linked to circadian rhythm disruption and retinal damage, and has also been associated with changes in neurodegeneration, aging, mortality, and oxidative stress in model organisms. This thesis explores the multifaceted effects of blue light exposure through two independent but complementary approaches. An initial rapid review of the current state of knowledge on blue light induced oxidative stress in humans was conducted. This revealed that the most studied …

A Comparison Of Diploid And Triploid Eastern Oysters For Aquaculture Production Under Extreme Temperatures And Salinities, Joshua H. Kim

LSU Master's Theses

Off-bottom aquaculture of Eastern oysters (Crassostrea virginica) is a nascent industry that is increasingly supported by the use of triploid oysters, which grow faster than diploids. Despite their growth advantage, elevated triploid mortality compared to diploids under high temperature, low salinity, or a combination of these conditions challenge consistent triploid production. Identifying the environmental thresholds at which differential triploid mortality occurs and predicting its economic impact are important to informing decision-making in oyster aquaculture. The goal of this thesis was to compare the biological and economic performance of diploid and triploid oysters under high temperature and low salinity conditions. …

The Aquatic Microbial Environment Shapes The Gut Microbiota, Brain, And Behavior Of Larval Amphibians, Kyle Emerson

Electronic Theses and Dissertations

Microbial communities comprising bacteria, viruses, fungi, and protists live within and on the surfaces of animal hosts. These microbial communities exist in symbiosis with the host, and heavily influence host physiology, development, health, and fitness. Gut-dwelling microbes (i.e., gut microbiota) contribute to host neurodevelopment through a bidirectional Microbiota-Gut-Brain (MGB) axis. Evidence of the MGB axis has been primarily derived from studies that use germ-free (GF) models, which commonly display altered neurophysiology and behavior compared to conventionally raised counterparts. Almost all studies of the MGB axis have used mammalian models in a biomedical framework, leaving a knowledge gap regarding the role …

Noise And Light Pollution Elicit Endocrine Responses In Urban But Not Forest Frogs, J. A. H. Smit, R. Vooijs, P. Lindenburg, Alexander T. Baugh, W. Halfwerk

Biology Faculty Works

Urban areas are characterised by the presence of sensory pollutants, such as anthropogenic noise and artificial light at night (ALAN). Animals can quickly adapt to novel environmental conditions by adjusting their behaviour, which is proximately regulated by endocrine systems. While endocrine responses to sensory pollution have been widely reported, this has not often been linked to changes in behaviour, hampering the understanding of adaptiveness of endocrine responses. Our aim was, therefore, to investigate the effects of urbanisation, specifically urban noise and light pollution, on hormone levels in male urban and forest túngara frogs (Engystomops pustulosus), a species with …

Comparing Ionoregulation And Modes Of Nitrogen Excretion Across The Life Cycle Of Parasitic And Non-Parasitic Lamprey Species, Shannon Davidson

Theses and Dissertations (Comprehensive)

Abstract

Ionoregulation and nitrogenous waste (N-waste) metabolism in fishes has been extensively documented in teleosts and elasmobranchs, but less so in lampreys (Petromizontiformes). All lamprey species undergo metamorphosis which drastically changes their physiology and modes of feeding. However, differences in ionoregulatory mechanisms due to anadromous versus non anadromous life history strategies emerge following metamorphosis in different lamprey species. Furthermore, some species, such as anadromous juvenile sea lamprey (Petromyzon marinus), are parasitic and migrate to seawater (SW) to ingest blood protein from host fishes, while juveniles of freshwater (FW), non-parasitic species, such as the American brook lamprey …

Impacts Of Environmental Stressors On Native South Dakota Amphibian Physiology And Survival, Danielle Jean Galvin

Dissertations and Theses

Amphibian populations around the world are declining, with some of the most likely drivers behind these declines including emerging infectious diseases and environmental contaminants. To address major gaps in the current literature, I sought to evaluate the effect of two major environmental stressors on various aspects of amphibian physiology: emerging infectious diseases and environmental contaminants. Emerging infectious diseases of amphibians include fungal, viral, and parasitic pathogens which have expanded in host range, either geographically or in competent host species. Environmental contaminants include chemicals which may be naturally occurring in the environment, or which may be introduced to the environment, often …

Investigating The Salinity Tolerance Of The Swordtail (Xiphophorus Hellerii), Alexandra Megan Krak

College of Science and Health Theses and Dissertations

The swordtail, Xiphophorus hellerii, is a freshwater fish species native to Mexico and Central America and is commonly used in the tropical aquarium trade. Swordtails have been shown to have limited survival in 6 ‰ salinity (Nanda et al., 2016), suggesting they may have a greater salinity tolerance than previously expected. Using a gradual acclimation method, we examined the salinity tolerance and swim performance of this species. Freshwater-reared female swordtails were housed in 29-gallon aquaria. A control group was held in freshwater throughout the experiment. For the experimental group, the salinity was increased by 2 ‰ every week until 30 …

Comparing Four Indices Of Physiological Stress In An Urban-Adapted Songbird Between Urban And Rural Habitats, Rachel Kaplan

Master of Science in Integrative Biology Theses

Birds show tremendous variation in the extent to which different species tolerate life in urban habitats, yet it remains unclear why some species thrive while others cannot. My work explores possible phenotypes that make an urban-adapted species, the European starling (Sturnus vulgaris), so successful in both rural and urban areas. Literature on stress-urbanization relationship remains highly equivocal partly due to an array of different study systems being compared as well as to key methodological differences. The present study quantified metrics of both acute stress (i.e., stress-induced corticosterone and breath rate) and chronic stress (i.e., baseline corticosterone and total …

Nutritional Ecology Of The Western Cottonmouth (Agkistrodon Piscivorus Leucostoma), Jason Ortega

Graduate Theses and Dissertations

Nutritional ecology aims to understand the factors that shape the diets of animals, how these ingested meals are processed, and how the assimilated nutrients are used to shape an organism’s interactions with its environment. As environmental parameters are altered due to anthropogenic changes, the availability and quality of prey may be altered. The alteration of the nutritional landscape can be devastating to nutritional specialists, yet generalist predators may be able to cope with these changes. The western cottonmouth (Agkistrodon piscivorus leucostoma) is a unique semiaquatic pitviper that can both forage along the land-water interface and in upland habitat when faced …

We Travel Together: Examining The Drivers And Functions Of Animal Movement In Biotic Seed Dispersal, Binod Borah

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plants and frugivorous animals exist in mutually beneficial relations, as these animals feed on fruits, ingest the seeds, and carry them away from the parent trees. Such dispersion of seeds over space helps them colonize new habitats, escape high mortality rates near their parent trees, and avoid competition with conspecifics. Therefore, seed dispersing animal movement can be critical for the persistence of plant populations. Yet what drives such seed disperser movement is often less understood and how it affects seed dispersal is little explored. In my dissertation, I investigate multiple drivers of seed disperser movement, link movement to potential seed …

Impacts Of Dietary Restriction On A Drosophila Model Of Werner Syndrome, Eileen Sember

College of Arts & Sciences Senior Theses

Werner syndrome (WS) is an autosomal recessive disorder that results in premature aging and occurs in 1 in 1,000,0000 to 1 in 10,000,000 people. In humans, WS is the result of mutations that render the WRN gene, that contains a helicase and an exonuclease domain, non-functional. Currently, there is no cure for WS in humans, making dietary and lifestyle interventions attractive for increasing the quality and longevity of lives. Diet restriction (DR) has been shown to extend the lifespan of several model organisms, including Drosophila melanogaster, making it a strong candidate for WS treatment. In this thesis, mutant flies …

Locomotor Biomechanics In Stream Gobies, Rhinogobius Sp.: Functional Performance Of Waterfall-Climbing Behavior, Ernest W. Murphy

Student Scholar Showcase

Gobiidae is the taxonomic classification of a large fish family comprising over 2,000 species. A few goby species have the unique ability of scaling waterfalls using pelvic fins that are fused into a suction disc (pelvic sucker) located on the ventral side of the body, aiding them in upstream migration to freshwater feeding and reproduction locations. This study aimed to investigate the locomotor biomechanics of Rhinogobius goby fish due to the lack of literature in the area. In particular, climbing performance variables (pressure differential, force, endurance, and kinematics of attachment), pelvic sucker fatigability, and ontogenetic patterns of physical development and …

Tracking The Progression Of Defects At The Neuromuscular Junction In Huntington's Disease, Katherine A. Trittschuh

Browse all Theses and Dissertations

Huntington’s disease (HD) is a genetic disorder associated with progressive cognitive and motor decline. Recent studies in HD models suggest primary peripheral pathologies arise independent of changes in the central nervous system. Our lab found defects in skeletal muscle occurring early in the progression of disease in transgenic R6/2 HD mice, resulting in membrane hyperexcitability. Additionally, there is evidence of decreased quantal content in late-stage R6/2 mice. Here, we investigate pre-synaptic and post-synaptic function at single neuromuscular junctions (NMJ) to make direct comparisons of disease progression in the muscle membrane and motor nerve terminal. We hypothesize that muscle membrane defects …

Radiation-Induced Gastrointestinal (Gi) Syndrome As A Function Of Age, Hongyan Li, Herman C. Kucharavy, Carla Hajj, Liyang Zhao, Guoqiang Hua, Ryan Glass, Phillip B. Paty, Zvi Fuks, Richard Kolesnick, Karen Hubbard, Adriana Haimovitz-Friedman

Publications and Research

Previous studies show increased sensitivity of older mice (28–29 months) compared with young adult mice (3 months, possessing a mature immune system) to radiation-induced GI lethality. Age-dependent lethality was associated with higher levels of apoptotic stem cells in small intestinal crypts that correlated with sphingomyelinase activity, a source of pro-apoptotic ceramide. The objective of this study is to determine whether the cycling crypt base columnar cells (CBCs) in aging animals are specifically more sensitive to radiation effects than the CBCs in young adult mice, and to identify factors that contribute to increased radiosensitivity. Mortality induced by subtotal body radiation was …

Quantifying Life History Energetics Of An Oviparous Elasmobranch Subject To Future Warming Water, Carolyn R. Wheeler

Graduate Doctoral Dissertations

Marine ectothermic fishes – fishes that do not regulate internal body temperature independent from the water temperature – are some of the most vulnerable organisms to rapid and alarming increases in environmental temperature occurring due to climate change mediated-ocean warming. For tropical fish species that live near their thermal maxima, this warming could be of grave consequence to individuals, populations, and whole marine ecosystems. Certain key life stages such as embryos and reproducing adults may be particularly vulnerable to warming given the excess energetic costs of these life stages, which may disallow compensation for extreme changes in temperature. One taxonomic …

Pollutants Corrupt Resilience Pathways Of Aging In The Nematode C. Elegans, Andrea Scharf, Annette Limke, Karl Heinz Guehrs, Anna Von Mikecz

Biological Sciences Faculty Research & Creative Works

Delaying aging while prolonging health and lifespan is a major goal in aging research. One promising strategy is to focus on reducing negative interventions such as pollution and their accelerating effect on age-related degeneration and disease. Here, we used the short-lived model organism C. elegans to analyze whether two candidate pollutants corrupt general aging pathways. We show that the emergent pollutant silica nanoparticles (NPs) and the classic xenobiotic inorganic mercury reduce lifespan and cause a premature protein aggregation phenotype. Comparative mass spectrometry revealed that increased insolubility of proteins with important functions in proteostasis is a shared phenotype of intrinsic- and …

Intracellular Hemin Is A Potent Inhibitor Of The Voltage-Gated Potassium Channel Kv10.1, Nirakar Sahoo, Kefan Yang, Alisa Bernert, Sandip M. Swain, Guido Gessner, Reinhard Kappl, Toni Kühl, Diana Imhof, Toshinori Hoshi, Roland Schönherr, Stefan H. Heinemann

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Heme, an iron-protoporphyrin IX complex, is a cofactor bound to various hemoproteins and supports a broad range of functions, such as electron transfer, oxygen transport, signal transduction, and drug metabolism. In recent years, there has been a growing recognition of heme as a non-genomic modulator of ion channel functions. Here, we show that intracellular free heme and hemin modulate human ether à go-go (hEAG1, Kv10.1) voltage-gated potassium channels. Application of hemin to the intracellular side potently inhibits Kv10.1 channels with an IC50 of about 4 nM under ambient and 63 nM under reducing conditions in a weakly voltage-dependent manner, …

An Ecological And Physiological Assessment Of Feather Mite-Bird Symbioses, Kevin James Krajcir

Student Theses and Dissertations

Feather mites are ectosymbiotic arthropods that reside primarily on the wing and tail feathers of most birds. Despite our growing understanding of feather mite biology, previous studies of the nature of the feather mite-avian host relationship report mutualism, parasitism, and commensalism. Such inconsistencies are likely due to narrow study designs that fail to capture the possibility of context dependency in this interaction. To provide some clarity surrounding the nature of this symbiotic system, we explored how geographical, climatic, and ecological contexts relate to variation in feather mite abundance and how that abundance, consequently, associates with multiple metrics of host condition …

Connecting Above- And Belowground Effects Of Climate Warming On Bumble Bee Health, Francis Mullan

Master of Science in Integrative Biology Theses

Climate warming has been identified as one of the primary factors causing worldwide pollinator declines. One of the most at-risk groups of pollinators is bumble bees (Bombus spp.). Bumble bees are common, widespread, and key pollinators of a wide range of crops and wild plants. Although studies have examined the thermal physiological traits of individual bumble bees to understand how they may be impacted by climate warming, little to no studies have examined how climate warming may impact whole bumble bee colonies both in their ability to thermoregulate their nest for their brood or in their ability to forage …

How Are Changes In Temperature And Salinity Impacting Intertidal Mussels?, Casey A. Martin

Student Research Symposium

Marine organisms living within the intertidal zones, such as mussels, experience a wide range of environmental conditions every day. Due to Climate change, these environments are transforming in such a way that may impact a mussels ability to successfully reproduce, grow, and live. Previous studies have shown that successful gamete development in freshwater mussels has been linked to temperature and species behavior has been observed to be influenced by salinity levels. In order to test the impact of temperature and salinity on mussel physiology, mussels were exposed to several treatments with varying conditions. Those conditions included a combination of a …

The Consequences Of Climate Change For Native Bee Assemblages, Melanie R. Kazenel

Biology ETDs

Recent declines in terrestrial arthropod biodiversity highlight the need to pinpoint which taxa and ecosystem services are most threatened, and why. But, for most of the world’s ~20,000 bee species, we lack robust evidence of population trends, and the role of climate change remains surprisingly little studied. I used long-term bee monitoring data from the Sevilleta Long-Term Ecological Research Program (Socorro, NM, USA), along with complementary experimental and observational data, to examine how climate relates to bee abundance and diversity patterns over time and space, and to identify the traits that govern bees’ climate sensitivities. Under climate change, drylands worldwide …

From Gene Expression To Physiology: A Study Of Chronic Thermal Tolerance In The Mytilus Edulis Species Complex, Lindsey Cate Schwartz

Theses and Dissertations

Rising ocean temperatures are a severe and ever-present threat to marine life. With environmental temperature having such a large impact on organismal performance, understanding the mechanisms which contribute to the ability to survive at higher temperatures is a crucial research focus. Significant progress has been made in discovering these mechanisms on the cellular, biochemical, and physiological levels, but is it much less common for those to be examined together. Using the Mytilus edulisspecies complex as a model system, this dissertation takes a closer look at how prolonged exposure to sub-lethal high temperatures impacts marine organisms on multiple levels of …

Relating Metabolic Phenotypes To Movement Behavior In Brook Trout, Jacob E. Bowman

All NMU Master's Theses

Brook trout movement-related life history strategies vary considerably and range from individuals that stay within the same 100 meters their entire life to individuals that are potamodromous or anadromous. Potential drivers of movement life histories have been the subject of much research in fish, with genetic subpopulation explanations often failing to explain the phenomenon. Metabolic phenotypes have been suggested as a possible driver for expression of different movement life histories. I investigated if metabolic phenotypes are related to movement strategies within a population of brook trout (Salvelinus fontinalis) in Unnamed Creek, a tributary to the Rock River, Alger …