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Full-Text Articles in Biology

Using Biometrics, Behavioral Observations, And Multiple Molecular Techniques To Assess The Impacts Of Changes In Temperature And Salinity On The Common Bay Mussel (Mytilus Trossulus), Casey Martin Nov 2023

Using Biometrics, Behavioral Observations, And Multiple Molecular Techniques To Assess The Impacts Of Changes In Temperature And Salinity On The Common Bay Mussel (Mytilus Trossulus), Casey Martin

Dissertations and Theses

The intertidal zone is a place of rapid and frequent change that is home to a variety of creatures who are essential to the integrity of the habitat. Mussels are robust sessile bivalves that anchor to the rocks of the intertidal. The prominent species on the Oregon Coast, the Common Bay Mussel (Mytilus trossulus), plays an essential role as a coastal food source, water column filter, and barrier to prevent erosion due to wave action. Mytilus trossulus withstands daily shifts in temperature, salinity, and tide, as well as seasonal changes. Global climate change due to excess carbon emissions …


Ser14-Rpn6 Phosphorylation Mediates The Activation Of 26s Proteasomes By Cyclic Amp And Protects Against Cardiac Proteotoxic Stress In Mice, Liuqing Yang Jan 2023

Ser14-Rpn6 Phosphorylation Mediates The Activation Of 26s Proteasomes By Cyclic Amp And Protects Against Cardiac Proteotoxic Stress In Mice, Liuqing Yang

Dissertations and Theses

A better understanding of how proteasome activity is regulated can facilitate the search for proteasome enhancement strategies for disease treatment. A cell culture study shows cAMP-dependent protein kinase (PKA) activates 26S proteasomes by phosphorylating Ser14 of RPN6 (pS14-RPN6), but this discovery and its physiological significance remain to be established in vivo. To test the hypothesis that pS14-RPN6 mediates the activation of proteasomes by PKA and reduces proteotoxicity in animals, two knock-in mouse models with Ser14 of endogenous Rpn6 mutated to either Ala (S14A) or Asp (S14D) to respectively block or mimic pS14-Rpn6 were created. In a PKA-dependent manner, cAMP augmentation …


Cop9 Signalosome Promotes Neointimal Hyperplasia Via Deneddyaltion And Csn5-Mediated Nuclear Export, Samiksha Giri Jan 2023

Cop9 Signalosome Promotes Neointimal Hyperplasia Via Deneddyaltion And Csn5-Mediated Nuclear Export, Samiksha Giri

Dissertations and Theses

Neointimal hyperplasia (NH) is a common pathological response to vascular injury and mediated primarily by vascular smooth muscle cell (VSMC) migration and proliferation. The COP9 signalosome (CSN) is formed by 8 canonical subunits (CSN1 through CSN8) with its deneddylation activity residing in CSN5. Each or some of CSN subunits may have deneddylation-independent function but this is not well established. Despite the CSN being known to be a key regulator of protein degradation, its role in vascular biology remains obscure. The present study was conducted to fill these critical gaps.Our immunohistochemistry analyses revealed substantially higher CSN5 levels in the neointimal VSMCs …


Temperature-Induced Activation Of The Reproductive Axis Through Melatonin-Mediated Changes In Thyrotropin, Treven J. Winters Jul 2021

Temperature-Induced Activation Of The Reproductive Axis Through Melatonin-Mediated Changes In Thyrotropin, Treven J. Winters

Dissertations and Theses

An animal's ability to synchronize life-history events or stages with optimal environmental conditions is paramount to successfully reproducing and maximizing fitness. Additional events including migration, foraging, rearing of young, and emergence from hibernation are all examples of processes under environmental control in one species or another. An exciting new mechanism involving neural thyroid hormone metabolism has been elucidated that links environmental control to the neuroendocrine reproductive axis. In birds and mammals with seasonal breeding cycles, this neuroendocrine pathway is activated by photoperiod-induced changes in thyroid stimulating hormone (TSH, also known as thyrotropin) production within the pars tuberalis region of the …


Assessing Well-Being Of Asian Elephants (Elephas Maximus) Through Major Events And Transitions, With Development And Aging, And Husbandry Changes, Sharon Stuart Glaeser Jul 2020

Assessing Well-Being Of Asian Elephants (Elephas Maximus) Through Major Events And Transitions, With Development And Aging, And Husbandry Changes, Sharon Stuart Glaeser

Dissertations and Theses

In this body of research, reproductive and adrenal hormones and behavior were used to evaluate individual and group responses to physiological, social, and environmental changes in zoo-housed Asian elephants, considering factors of sex, age, and life stage. Animals experience physiological, social, and environmental changes as part of their natural history and individual life experience. Measures of both positive and negative states are needed to assess the impact of these changes at the individual and group level. Such measures can help us better understand how animals cope with a changing environment, and can help inform management decisions. Through longitudinal analyses of …


Energy Stores And Life-History Transitions In Red-Sided Garter Snakes (Thamnophis Sirtalis Parietalis), Rachel Catharine Wilson Jul 2020

Energy Stores And Life-History Transitions In Red-Sided Garter Snakes (Thamnophis Sirtalis Parietalis), Rachel Catharine Wilson

Dissertations and Theses

All organisms must prioritize investment in either reproductive or self-maintenance activities. Despite this established paradigm, our understanding of how organisms choose to prioritize certain behaviors and physiologies over others remains limited. It is likely that an organism's energy status not only influences variation in reproductive effort, but also transitions to and from reproductive activities. My dissertation aims to investigate how energy metrics (body condition index, adipocyte follicle size, and liver glycogen) relate to reproduction and associated life-history stages in red-sided garter snakes (Thamnophis sirtalis parietalis). Chapter two examines if energy metrics differ with migratory status and sex in …


Whole Body I=In Vivo Vascular Compliance In Two Amphibians, Bufo Marinus And Rana Cate, Todd Micheal Hoagland Oct 1997

Whole Body I=In Vivo Vascular Compliance In Two Amphibians, Bufo Marinus And Rana Cate, Todd Micheal Hoagland

Dissertations and Theses

The mean circulatory filling pressure (MCFP), vascular compliance (C) and unstressed volume (USV) were measured in Bufo marinus and Rana catesbeiana, using an in vivo preparation. Capacitance curves were constructed by varying total vascular volume and then measuring MCFP. These capacitance curves enable the extrapolation of USV and the measurement of vascular compliance. The MCFP, C, and USV were 8.6 ± 0.2 (mmHg), 3.7 (ml· mmHg-1 · kg- 1 ) and 2.5 (ml), respectively, in B. marinus. The MCFP, C, and USV were 9.5 ± 0.1 (mmHg), 2.2 (ml· mmHg-1 · kg- 1 ) and 14.2 (ml), respectively, …


Brainstem Auditory Evoked Potentials In Anuran Amphibians, Marc Brandon Carey May 1992

Brainstem Auditory Evoked Potentials In Anuran Amphibians, Marc Brandon Carey

Dissertations and Theses

In this study, I looked at the effects of sound level, temperature and dehydration/hypernatremia on the brainstem auditory evoked potential (BAEP) of four species of anuran amphibians (Rana pipiens, Rana catesbeiana, Bufo americanus and Bufo terrestris). The BAEP was used because it allowed me to monitor both the peripheral and central aspects of auditory nervous function simultaneously and over a long period of time.


Nitrogen And Iron Interactions In Filamentous Cyanobacteria, David Allen Hutchins Jan 1989

Nitrogen And Iron Interactions In Filamentous Cyanobacteria, David Allen Hutchins

Dissertations and Theses

The investigations described in this paper are an attempt to further define and quantify the interrelationship of nitrogen fixation and iron nutritional physiology in these two species. Chapter II will present and compare data on nutritional ratios of field collected Trichodesmium colonies and laboratory Anabaena cultures, with the intent of examining possible correlations between observed iron levels and protein nitrogen and chlorophyll concentrations, as well as nitrogen fixation rates. Chapter Ill is an examination of nitrogen fixation and siderophore production in Anabaena with emphasis on the possible implications of hypothesized synergistic effects of these two physiological capabilities on cyanobacterial dominance …


The Effect Of Cold Acclimation On The Temperature Preference Of The Goldfish, Carassius Auratus, And The Brown Bullhead, Ictalurus Nebulosus, Alfred Lord Nov 1987

The Effect Of Cold Acclimation On The Temperature Preference Of The Goldfish, Carassius Auratus, And The Brown Bullhead, Ictalurus Nebulosus, Alfred Lord

Dissertations and Theses

Two species of fish, Carassius auratus and Ictalurus nebulosus, were subjected to cold acclimation regimes. Acclimation temperatures were slowly lowered to 3°C, then held for a period of time. At various times during this regime, fish were taken out and allowed to spend time in a temperature gradient to determine their preferred temperatures. Carassius were left in the gradient just long enough to determine a measure of the acute temperature preference, while Ictalurus were left in the temperature gradient for longer periods of time to observe any changes that might occur as the fish adjusted to selected temperatures. In …


Decrease In Selected Temperature After Intracranial Dopamine Injections In Goldfish, Hercules Theodore Panayiotides-Djaferis Aug 1987

Decrease In Selected Temperature After Intracranial Dopamine Injections In Goldfish, Hercules Theodore Panayiotides-Djaferis

Dissertations and Theses

Goldfish (Carassius auratus) (40-80g) were injected with dopamine into the forebrain to study the possible involvement of this amine in central temperature regulation in these fish. Dopamine caused a decrease in selected temperature after injection into the rostral nucleus preopticus periventricularis (NPP). This effect was dependent on the dose of dopamine administered. Doses of 25, 50, 100 and 250 ng were used, injected in a volume of 0.2μ1. Injections in regions adjacent to the NPP elicited hypothermic effects only at the higher dosages. These effects were not consistent. Injections in caudal regions of the NPP elicited no effect. …


The Effect Of Body Temperature On Arteriovenous Oxygen Difference During Rest And Activity In The Toad, Bufo Marinus, Wayne Bryant Palioca Jul 1987

The Effect Of Body Temperature On Arteriovenous Oxygen Difference During Rest And Activity In The Toad, Bufo Marinus, Wayne Bryant Palioca

Dissertations and Theses

The relative contribution of arteriovenous oxygen (A-V O2) difference to thermally-induced and activity-induced changes in metabolic rate (VO2) were delineated in the toad, B. marinus. In conjunction, the influence of rest and activity, temperature, and removal of the pericardial sac on separation efficiency (Es) in the anuran ventricle was determined by direct measurement of arterial and venous percent oxygen saturation (% saturation), using a microsampling technique.


Norepinephrine And Temperature Regulation In Goldfish, Lonnie Paul Wollmuth Jan 1987

Norepinephrine And Temperature Regulation In Goldfish, Lonnie Paul Wollmuth

Dissertations and Theses

Cannulae were implanted into forebrain loci of goldfish (Carassius auratus; 45-90 g) to determine (i) the effects and site of action of intracranial norepinephrine (NE) injections on behavioral thermoregulation and (ii) the mechanism and the types of adrenoreceptors involved in the thermoregulatory effect of NE. After 30 min in a thermal gradient, implanted fish were injected with norepinephrinebitartrate salt (2.5-500 ng NE) in a total volume of 0.2 ul (carrier was 0.7% NaCl). Injections of 5, 10, 25, and 50 ng NE into the anterior aspect of the nucleus preopticus periventricularis (NPP1 Peter and Gill 1975) led to consistent, dose-dependent …


Effect Of Ethanol On Thermoregulation In The Goldfish Carassius Auratus, Candace Sharon O'Connor May 1986

Effect Of Ethanol On Thermoregulation In The Goldfish Carassius Auratus, Candace Sharon O'Connor

Dissertations and Theses

In an attempt to elucidate the mechanism by which ethanol affects vertebrate thermoregulation, the effect of ethanol on temperature selection was studied in the goldfish, Carassius auratus. Ethanol was administered to 10 to 15 g fish by mixing it in the water of a temperature gradient. The dose response curve was very steep between 0.5% (v/v) ethanol (no response) and 0.7% (significant lowering of selected temperature in treated fish). Fish were exposed to concentrations of ethanol as high as 1.7%, at which concentration most experimental fish lost their ability to swim upright in the water. At concentrations higher than …


The Effect Of Salinity On Habitat Selection Of Two Oregon Chiton Species (Katharina Tunicata And Mopalia Hindsii), David Carl Rostal Mar 1986

The Effect Of Salinity On Habitat Selection Of Two Oregon Chiton Species (Katharina Tunicata And Mopalia Hindsii), David Carl Rostal

Dissertations and Theses

Adult specimens of Katharina tunicata (mean weight = 10.23 grams) and Mopalia hindsii (mean weight = 10.90 grams) were tested for osmotic stress tolerance and oxygen consumption rates in a series of salinities (120%, 100%, 80%, 60%, and 40% seawater) at 11°C and 16L:8D photoperiod. K. tunicata and M. hindsii displayed similar trends in percent body weight variation and volume regulatory responses to osmotic stress. However, K. tunicata experienced a significantly higher percent body weight increase than did M. hindsii in response to hypo-osmotic conditions (80%, 60%, and 40% seawater). The mean rates of oxygen consumption per salinity for the …


The Contribution Of The Lymph Hearts In Compensation For Acute Hypovolemic Stress In The Toad Bufo Marinus, Mark Baustian Jan 1986

The Contribution Of The Lymph Hearts In Compensation For Acute Hypovolemic Stress In The Toad Bufo Marinus, Mark Baustian

Dissertations and Theses

Currently published data on the role of the lymphatic system in amphibians are inadequate and contradictory. Estimates of the rate of formation of lymph and the role of the lymph hearts in returning this fluid to the circulation are not based on actual volume determinations but rather estimates derived from changes in hematocrit using published values of plasma and blood volume. The lymph hearts are known to be vital to the maintenance of normal fluid compartment physiology and to increase their rate of activity during episodes of hypovolemic stress. Yet, significant redistribution of body fluids following hemorrage appears to occur …


Hemodynamics During Pregnancy : A Model For Cardiac Enlargement, David James Mendelson Jan 1986

Hemodynamics During Pregnancy : A Model For Cardiac Enlargement, David James Mendelson

Dissertations and Theses

Cardiac output Increases by 30-50% during mammal Ian pregnancy. This Increase Is reflected by elevation In both heart rate and stroke volume. The primary mechanism of Increased stroke volume appears to be cardiac enlargement, rather than increased preload, afterload, or contractility. Animal studies have shown that enlargement of the heart occurs prior to an Increase In uterine blood flow during pregnancy and this type of enlargement can be mimicked by sex steroid administration.

Systemic vascular resistance greatly decreases during pregnancy and with sex steroid administration. It has been postulated that systemic vascular resistance may be a signal for heart size …


The Significance Of Hypovolemia In Dehydrational Death In Anurans, Peter Blair Kimmel Jan 1985

The Significance Of Hypovolemia In Dehydrational Death In Anurans, Peter Blair Kimmel

Dissertations and Theses

The importance of hypovolemia in dehydrational death was assessed in two anuran species. Xenopus laeyis, a species which experiences a significant reduction in circulating plasma volume with dehydration, was used to evaluate the role of sympathetic reflex compensation in hypovolemia. Adrenergic blockade with propranolol or phenoxybenzamine produced no significant reduction in dehydration tolerance in this species, although β-blockade with propranolol appeared to have a minor effect. The role of hypovolemic shock in the terminal circulatory collapse that precedes death in dehydrating anurans was investigated in the toad, Bufo marinus. The activity of lysosomal proteinases (cathepsins) was used as an indicator …


Effects Of Dehydration On Hemoglobin Oxygen Affinity And Blood Cell Volume In Two Anurans, Andrew Christopher Zygmunt Aug 1984

Effects Of Dehydration On Hemoglobin Oxygen Affinity And Blood Cell Volume In Two Anurans, Andrew Christopher Zygmunt

Dissertations and Theses

Two aspects of possible adaptation in cardiovascular performance caused by increased plasma electrolytes were examined. Cells in anisotonic plasma may either act as osmometers or volume regulate. Blood flow rate is dependent upon cell viscosity, which in turn is a consequence of cell volume and membrane deform-ability. Cell volume changes which increase membrane deform-ability will thus potentially extend the limits of dehydration tolerance. It was found in R. catesbeiana and B. marinus that red blood cell is maintain constant volume during dehydration. Cells in vitro initially lose water, but then sodium, potassium and water move into the cell. Cell viscosity …


The Metabolic Cost Of Behavioral Thermoregulation Of Body Temperature In The Northern Alligator Lizard Gerrhonotus Coeruleus, And How It Affects The Classical Concept Of Eurythermality, James Dudley Campbell Jan 1981

The Metabolic Cost Of Behavioral Thermoregulation Of Body Temperature In The Northern Alligator Lizard Gerrhonotus Coeruleus, And How It Affects The Classical Concept Of Eurythermality, James Dudley Campbell

Dissertations and Theses

The effect of total metabolic cost expenditures on the precision of behavioral thermoregulation was investigated for the purportedly eurythermic Northern Alligator lizard (Gerrhonotus coeruleus). An operant apparatus was designed to test metabolic output at different heat reinforcement magnitudes. The mean TB reflected in each trial was positively correlated to the length of reinforcement. The shuttle rate during each trial was inversely correlated to the length of reinforcement. The standard deviation and total metabolic costs did not vary significantly between trials undertaken at the same ambient temperature. Eurythermality in G. coeruleus is caused by fluctuations in preferred body temperature and …