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Comparative and Evolutionary Physiology Commons™
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Articles 1 - 11 of 11
Full-Text Articles in Comparative and Evolutionary Physiology
Hypothalamic Manipulation Of The Anuran Hpg Axis: Alternative Hormones And A Non-Invasive Administration Route For Amphibian Assisted Reproductive Technologies (Art), Erin Michelle Saylor
Hypothalamic Manipulation Of The Anuran Hpg Axis: Alternative Hormones And A Non-Invasive Administration Route For Amphibian Assisted Reproductive Technologies (Art), Erin Michelle Saylor
Theses and Dissertations
Amidst the amphibian extinction crisis, in situ and ex situ amphibian species conservation initiatives utilize assisted reproductive technologies for optimal genetic management of captive and wild populations. Development of effective, simple, low-cost methods for obtaining gametes for artificial fertilization, sperm biobanking, or natural breeding alleviates obstacles for institutions or programs to apply reproductive technologies. Objectives herein include investigating the efficacy of alternative hormones for inducing spermiation, an alternative hormone administration route for inducing ovulation, exploring the physiological effects of hormone therapy, and utilizing sperm from deceased animals for biobanking.
Does Stress Physiology Mediate Disease Resistance In The Arizona Tiger Salamander (Ambystoma Mavortium Nebulosum)?, Megan Zerger
Does Stress Physiology Mediate Disease Resistance In The Arizona Tiger Salamander (Ambystoma Mavortium Nebulosum)?, Megan Zerger
2023 Midwest Ecology & Evolution Conference
Amphibian biodiversity has greatly diminished in recent years due to disease. Panzootic pathogenic fungi Batrachochytrium dendrobatidis (Bd) causes the deadly disease chytridiomycosis (chytrid), a primary driver of catastrophic global amphibian declines and extinctions. The pathogenesis of chytrid is still unclear, as certain species and individuals within a species are differentially affected. Susceptibility and mortality of Bd are influenced by prolonged chronic stress. Prolonged glucocorticoid activity deleteriously affects many of the same physiological processes as Bd infections, and corticosterone is the primary glucocorticoid released by amphibians in response to stress. Thus, the objective of our study is to assess …
Rediscovering The Axolotl As A Model For Thyroid Hormone Dependent Development, Anne Crowner, Shivam Khatri, Dana Blichmann, S. Randal Voss
Rediscovering The Axolotl As A Model For Thyroid Hormone Dependent Development, Anne Crowner, Shivam Khatri, Dana Blichmann, S. Randal Voss
Neuroscience Faculty Publications
The Mexican axolotl (Ambystoma mexicanum) is an important model organism in biomedical research. Much current attention is focused on the axolotl's amazing ability to regenerate tissues and whole organs after injury. However, not forgotten is the axolotl's equally amazing ability to thwart aspects of tissue maturation and retain juvenile morphology into the adult phase of life. Unlike close tiger salamander relatives that undergo a thyroid hormone regulated metamorphosis, the axolotl does not typically undergo a metamorphosis. Instead, the axolotl exhibits a paedomorphic mode of development that enables a completely aquatic life cycle. The evolution of paedomorphosis allowed axolotls …
Population Health Of Spotted Salamanders (Ambystoma Maculatum) In Created Vernal Pools: An Integrative Approach, Alice R. Millikin
Population Health Of Spotted Salamanders (Ambystoma Maculatum) In Created Vernal Pools: An Integrative Approach, Alice R. Millikin
Graduate Theses, Dissertations, and Problem Reports (ETD)
Habitat creation is an important tool for conservation to counteract habitat loss and degradation. Vernal pools are susceptible to destruction due to limited detection, protection, and regulation. These wetlands provide fishless breeding habitat for many amphibian species including spotted salamanders (Ambystoma maculatum) in eastern North America. Determining whether created vernal pool habitat is successful is often determined by demographic data of colonizing populations. I suggest that hormone levels, population genetics, and disease prevalence can improve our understanding of population health in created habitat. The goal of this dissertation was to assess the health of spotted salamander larvae in …
Molecular Characterization Of The Mummichog (Fundulus Heteroclitus) Ovarian Steroidogenic Pathway And Implications For Exogenous Estrogen Effects During Follicular Development, Thiviya Kanagasabesan
Molecular Characterization Of The Mummichog (Fundulus Heteroclitus) Ovarian Steroidogenic Pathway And Implications For Exogenous Estrogen Effects During Follicular Development, Thiviya Kanagasabesan
Theses and Dissertations (Comprehensive)
This study investigated ovarian development in Fundulus heteroclitus (mummichog), through molecular characterization of key mediators in the ovarian steroidogenic pathway; these included ovarian StAR (steroidogenic acute regulatory protein), cytochrome P450 enzymes, estrogen receptors (ERα, ERβ1 and ERβ2), and gonadotropin receptors (FSHr and LHr); additionally, hepatic vitellogenin (VTG1) and ERs, and brain P450 aromatase (P450arom; CYP19b) were studied. Fish were staged into cortical alveolus, vitellogenic, early mature, late mature, and ovulating stages of maturation; blood (plasma), ovary (tissue and isolated ovarian follicles per stage), liver, and brains were collected. Testosterone (T), 17β-estradiol (E2) and maturation inducing steroid (MIS), measured …
Organizational Effects Of Defeminizing Toxicants: Lessons Learned From An Environmental Sentinel Organism, The Fathead Minnow., Jonathan Ali
Organizational Effects Of Defeminizing Toxicants: Lessons Learned From An Environmental Sentinel Organism, The Fathead Minnow., Jonathan Ali
Theses & Dissertations
Endocrine disrupting compounds (EDCs) are chemicals that interfere with hormone function and are increasingly detected in aquatic environments, where they elicit adverse effects from exposed organisms. The toxicological effects of EDCs can be described as either activational (reversible) or organizational (irreversible), where the latter are associated with adverse outcomes in reproductive performance of adult fish. However, few studies have investigated the organizational impacts of anti-estrogenic or “defeminizing” EDCs, e.g. agrichemicals or pharmacological agents, in an environmentally-relevant or “sentinel” species. The objective of this study was to investigate the impacts of early-life EDC-initiated changes in estrogenic gene expression on organizational effects …
Characterization Of Andrenocortical Tissue Morphology, Histology, And Steroid Synthesis Among Finetooth (Carcharhinus Isodon), Blacktip (Carcharhinus Limbatus), Atlantic Sharpnose (Rhizoprionodon Terraenovae), And Bonnethead (Sphyrna Tiburo) Sharks, Danielle Elizabeth Bailey
Master's Theses
Adrenocortical (interrenal) tissue is composed of steroidogenic cells that produce corticosteroids involved in the stress response and hydromineral balance. Previous research characterizing the elasmobranch interrenal suggests that the number of interrenal bodies that produce the single primary corticosteroid, 1a-hydroxycorticosterone (1a-OHB), varies among species. However, potential species-specific differences in the amount of interrenal tissue and major steroid products produced have been understudied. To address this critical gap in our understanding of elasmobranch biology, this study examined interrenal morphology, cell structure, steroidogenic enzyme distribution (3bHSD), and steroid production in four shark species: Finetooth Carcharhinus isodon, Blacktip Carcharhinus limbatus, Atlantic Sharpnose …
The Proteomic Response In The Crustacean Molting Gland Of Land Crab Gecarcinus Lateralis In Response To Artificially Induced Molting Throughout Its Molting Cycle., Andrea Reider, Talia B. Head, Lars Tomanek, Donald L. Mykles
The Proteomic Response In The Crustacean Molting Gland Of Land Crab Gecarcinus Lateralis In Response To Artificially Induced Molting Throughout Its Molting Cycle., Andrea Reider, Talia B. Head, Lars Tomanek, Donald L. Mykles
STAR Program Research Presentations
Molting in crustaceans is a highly complex physiological process involving negative regulation by two paired endocrine glands, the X-organ/sinus gland complex (XO/SG) and the Y-organ (YO). The XO/SG complex is responsible for making molt-inhibiting hormone (MIH) which negatively regulates synthesis of molting hormones (ecdysteroids) by the YO. Eyestalk ablation (ESA) removes the source of MIH and provides an experimental means to manipulate and induce molting, although the physiological effects of ESA on the YO have not been fully characterized. Analysis of gene expression in the XOs and YOs has lead to the development of a proposed molecular signaling pathway which …
Effect Of The Acute Stress Response On Foraging Behavior In Mountain White-Crowned Sparrows, Zonotrichia Leucophrys, Sarah C. Osborne
Effect Of The Acute Stress Response On Foraging Behavior In Mountain White-Crowned Sparrows, Zonotrichia Leucophrys, Sarah C. Osborne
Scripps Senior Theses
Free-living vertebrates likely encounter many stressors throughout their lifetime, from fighting off a predator to coping with unpredictable weather. As a result, vertebrates will mount an acute response to the stressors. Here, we outline previous research conducted in behavioral endocrinology and stress physiology as it relates to our research. We then discuss our study with white-crowned sparrows (Zonotrichia leucophrys) in Tioga Pass Meadow, in which we examined how the acute stress response affects foraging behavior 24 hours after a stressor. In birds that underwent a stress series, we found there to be a significant 57% decrease in foraging …
The Relationship Between 11-Ketotestosterone, Cortisol, And Testosterone And Condition Index For Poecilia Reticulata, Shelly Gupta, Brandy G. Kalbach
The Relationship Between 11-Ketotestosterone, Cortisol, And Testosterone And Condition Index For Poecilia Reticulata, Shelly Gupta, Brandy G. Kalbach
Biological Sciences
The guppy, Poecilia reticulata, is a common study organism for behavioral and other ecological experiments (Houde, 1997). As far as we know, no previous data have been compiled regarding hormones and condition index of guppies. In this experiment we examined the relationship between circulating levels of three hormones (testosterone, 11-ketotestosterone and cortisol) and condition index in males and also made comparisons among the hormone levels, for three guppy sites from the northern range of Trinidad – Aripo River, Marianne River and Small Crayfish River. Hormone samples were obtained using non-invasive water borne techniques and quantified by our collaborator. The condition …
Mice Deficient In The Serine/Threonine Protein Kinase Vrk1 Are Infertile Due To A Progressive Loss Of Spermatogonia, Matthew S. Wiebe, R. Jeremy Nichols, Tyler P. Molitor, Jill K. Lindgren, Paula Traktman
Mice Deficient In The Serine/Threonine Protein Kinase Vrk1 Are Infertile Due To A Progressive Loss Of Spermatogonia, Matthew S. Wiebe, R. Jeremy Nichols, Tyler P. Molitor, Jill K. Lindgren, Paula Traktman
Nebraska Center for Virology: Faculty Publications
The VRK1 protein kinase has been implicated as a proproliferative factor. Genetic analyses of mutant alleles of the Drosophila and Caenorhabditis elegans VRK1 homologs have revealed phenotypes ranging from embryonic lethality to mitotic and meiotic defects with resultant sterility. Herein, we describe the first genetic analysis of murine VRK1. Two lines of mice containing distinct gene-trap integrations into the Vrk1 locus were established. Insertion into intron 12 (GT12) spared VRK1 function, enabling the examination of VRK1 expression in situ. Insertion into intron 3 (GT3) disrupted VRK1 function, but incomplete splicing to the gene trap rendered this allele hypomorphic (~15% of …