Physiology Commons^™

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 …

The Effect Of Alkalinity On Lampricide Effectiveness And Gill Physiology In Invasive Sea Lamprey (Petromyzon Marinus), Alexandre J. Walsh

Theses and Dissertations (Comprehensive)

The pesticides, 3-trifluoromethyl-4-nitrophenol (TFM) and niclosamide are used to control populations of invasive sea lamprey (Petromyzon marinus) in the Laurentian Great Lakes of North America. Added to streams infested with larval sea lamprey, the effectiveness of these pesticides, commonly called lampricides, are strongly influenced by water pH, with greater toxicity for both TFM and niclosamide in lower pH than higher pH water. However, the TFM and niclosamide sensitivity of sea lamprey are also greater in poorly buffered, low alkalinity water than in high alkalinity water but it is unclear why. One goal of my thesis was to propose …

Design And Validation Of Artificial Feeders To Study Feeding Preferences And Growth Of Hematophagous Juvenile Sea Lamprey (Petromyzon Marinus), Gracie Li-Ting-Wai

Theses and Dissertations (Comprehensive)

The parasitic and invasive land-locked sea lamprey Petromyzon marinus populations contributed to the collapse of the Great Lakes fisheries in the mid-1900s, while native anadromous populations are currently under threat and require conservation efforts for protection. Despite the increasing concern for both populations of this species, the juvenile stage of the sea lamprey’s life cycle has not been well studied. This is due, in part, to ethical concerns raised around holding live host fish with juveniles and the lack of an alternative feeding method to maintain these juveniles in the laboratory. The feeder should be designed to minimize fouling of …

Physiological Impacts Of Lampricides On Invasive Sea Lamprey (Petromyzon Marinus) And Non-Target Fishes, Razvan, Adrian Ionescu

Theses and Dissertations (Comprehensive)

Parasitic sea lamprey (Petromyzon marinus) ingest large quantities of blood from fishes using their oral disc and rasping tongue, most often killing the host. In the early 1900s, sea lamprey invaded the Laurentian Great Lakes, decimating sport, commercial and culturally significant fisheries. Since the early 1960s, chemical control using the lampricides 3- trifluoromethyl-4-nitrophenol (TFM) and niclosamide have helped to reduce sea lamprey populations by 90%. Lampricides are applied to larval lamprey nursery streams targeting many generations of lamprey at once. However, there is concern about the potential adverse effects of lampricides on other fishes, particularly vulnerable lake sturgeon (Acipenser fulvescens) …

Role Of Training Mode On Individual And Group Responses To Sprint Interval Training, Lauren T. Digby, Seth F. Mccarthy, Claudia Jarosz, Derek P.D. Bornath, Jessica A.L. Tucker, Tom J. Hazell

Theses and Dissertations (Comprehensive)

Improvements in V̇O_2peak decrease the risk of heart disease and all-cause mortality, and is predictive of overall health. This study compared the group and individual responses of V̇O_2peak, as well as group responses of aerobic performance and anaerobic capacity following running and cycling sprint interval training (SIT) to determine the optimal modality. Twenty-three recreationally active young adults (males: n = 16, BMI = 27.5±4.9; females: n = 7, BMI = 23.6±3.0) completed 3 training sessions/week for 3 weeks (9 sessions). Pre- and post-testing measures included: aerobic capacity (V̇O_2peak), aerobic performance (time trial), and anaerobic capacity …

Spinal Motor Neuron Excitability And Balance Control Changes Following Downslope Walking, Nikki Aitcheson-Huehn

Theses and Dissertations (Comprehensive)

Downslope walking (DSW) has been proposed as a rehabilitation tool for people with Multiple Sclerosis (PwMS) although there are mixed findings in young adults (YA) regarding the balance control changes, despite both populations experiencing depressed spinal motor neuron (MN) pool excitability. Our aim was to determine whether YAs could demonstrate improved balance control in conjunction with SOL H reflex depression (estimate of spinal MN excitability) following DSW. We also aimed to determine whether reciprocal inhibition was a potential mechanism for H reflex depression via conditioned SOL H reflexes. Thirty young adults (23±1.4y, 6 males) were assigned to 30-minutes of DSW …

The Task At Hand: Fatigue-Associated Changes To Corticospinal Excitability During Writing, Kezia Cinelli

Theses and Dissertations (Comprehensive)

Corticospinal excitability as measured via transcranial magnetic stimulation (TMS) is highly dependent on the task being performed at the time of stimulation. As such, this study sought out to measure corticospinal excitability during the relevant, daily task of writing and compare it to the conventional abduction task often utilized. We used single-pulse motor evoked potentials (MEPs) to provide a measure of corticospinal excitability and cortical silent period (CSP) duration, and paired-pulse conditioned MEPs to assess short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) recorded from the right first dorsal interosseous (FDI) of 19 participants on two randomized and counter-balanced days. …

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 …

The Influence Of Physiological And Abiotic Factors On The Sensitivity Of The Sea Lamprey (Petromyzon Marinus) To The Lampricide 3-Trifluoromethyl-4-Nitrophenol (Tfm), Alexandra Muhametsafina

Theses and Dissertations (Comprehensive)

Invasive sea lamprey (Petromyzon marinus) in the Great Lakes are controlled using the pesticide (lampricide) 3-trifluoromethyl-4-nitrophenol (TFM), which is applied to nursery streams containing larval lamprey. The toxicity of TFM to lamprey is affected by various environmental and physiological factors, which can lead to residual lamprey that survive TFM treatment. The goal of this study was to investigate how abiotic (season and temperature) factors interacted with physiological parameters (whole body and tissue energy reserves) to influence TFM sensitivity in sea lamprey. Toxicity tests were conducted at different times of the year (spring, early and late summer, fall) and …

Gill Structure & Function In Parasitic And Non-Parasitic Lampreys: The Effects Of Metamorphosis And Freshwater-Seawater Transfer, Julia Sunga

Theses and Dissertations (Comprehensive)

Lamprey (Petromyzontiformes) are a phylogenetically ancient group of jawless fishes that begin their lives as filter-feeding larvae (ammocoetes) before undergoing a complex metamorphosis into juvenile lamprey that involves major changes to their internal and external body plan. Some parasitic species, such as the sea lamprey (Petromyzon marinus), migrate to sea following metamorphosis, where they use their oral discs and rasping tongue to attach to and ingest vast quantities of blood from fishes. Thus, sea lamprey have to counter the simultaneous challenges of hyposmoregulation in sea water and the generation of large quantities of ammonia due to the …

Examining The Effects Of Interleukin-6 On Appetite Regulatory Peptides In Lean And Obese Sedentary Males, Greg L. Mckie

Theses and Dissertations (Comprehensive)

Acute moderate-intensity exercise transiently suppresses appetite via fluctuations in the appetite-regulatory peptides acylated ghrelin (AG), peptide tyrosine-tyrosine_3-36 (PYY_3-36), and active glucagon-like peptide-1 (GLP-1). Importantly, these effects do not lead to compensatory changes in energy intake in normal weight or obese individuals, highlighting the potential for exercise to induce acute energy deficits. One potential mechanism for these effects is increased post-exercise plasma concentrations of interleukin (IL)-6, as IL-6 has demonstrated appetite-inhibitory effects in animal and cell culture models. Given obesity is characterized by a state of chronic low-grade inflammation and associated with upregulated IL-6, this study sought to …

The Fatigue-Associated Changes In Estimates Of Persistent Inward Current In Human Motor Neurons, Chris Compton

Theses and Dissertations (Comprehensive)

Neuromuscular fatigue is associated with reduced supraspinal drive. Similarly, intracortical facilitation and muscle activation are reduced following concussion. Both fatigue and mild traumatic brain injury are associated with increased noradrenergic and serotonergic activity in animal models. Given that monoaminergic-dependent persistent inward currents (PIC) set spinal motor neuron (MN) gain, we speculate that PIC will increase during fatigue to compensate for supraspinal hypoexcitability and that this will be more pronounced in people with concussion. Therefore, the purpose of this experiment was to assess spinal MN excitability during fatigue in people with concussion and healthy controls. 20 participants (10 concussion, average age …

Influence Of Topography And Moisture And Nutrient Availability On Green Alder Function On The Low Arctic Tundra, Nt, Katherine Louise Black Ms., Jennifer Lynn Baltzer Dr.

Theses and Dissertations (Comprehensive)

The Arctic has warmed by at least 3^°C over the past 50 years and this rapid warming is expected to continue. Climate warming is driving the proliferation of shrubs across the tundra biome with implications for energy balance, climate, hydrology, nutrient cycling, and biodiversity. Changes in tundra plant water use attributable to shrub expansion are predicted to increase evapotranspirative water loss which may amplify local warming and reduce run-off. However, little is known about the extent to which shrubs will enhance evapotranspirative water loss in these systems. Direct measures of shrub water use are needed to accurately predict …

The Role Of Oxidative Stress In The Mechanisms Of Ammonia-Induced Brain Swelling And Tolerance In The Goldfish (Carassius Auratus), David F. Jones Lisser Mr.

Theses and Dissertations (Comprehensive)

Toxic build-ups of ammonia can cause potentially fatal brain swelling in mammals, but such swelling is reversible in the anoxia- and ammonia-tolerant goldfish (Carassius auratus). The mechanisms of ammonia-induced brain swelling and tolerance remain elusive, but several studies have suggested a role for reactive oxygen species (ROS), which may damage proteins and lipids in the plasma membrane of astrocytes in the brain. As a result, osmotic gradients across cell membranes may be altered leading to water uptake by astrocytes and swelling. While a role for ROS has been proposed in mammals, no studies have addressed this question in …

Changes In Brain Water Content In The Rainbow Trout (Oncorhynchus Mykiss) And In The Goldfish (Carassius Auratus) Due To High External Ammonia Exposure, Phillip Q.H. Pham-Ho

Theses and Dissertations (Comprehensive)

In fishes, hyperammonemia may occur following feeding or exposure to abnormally high concentrations of environmental ammonia due to sewage effluents, agricultural run-off and in crowded aquaculture pens. Increased internal ammonia can result in hyperactivity, convulsions, coma and death. In mammals, it is also associated with potentially fatal brain edema, in which the accumulation of intracellular water results in swelling, increased intracranical pressure and herniation leading to death. Recently it was shown that rainbow trout (Oncorhynchus mykiss) and goldfish (Carassius auratus) experience brain swelling following exposure to high external ammonia (HEA). However, the mechanism of ammonia-induced brain …

The Influence Of Abiotic Factors On The Uptake And Elimination Of 3-Trifluoromethyl-4-Nitrophenol By Larval Sea Lamprey (Petromyzon Marinus), Benjamin Livingston Hlina

Theses and Dissertations (Comprehensive)

The backbone of sea lamprey (Petromyzon marinus) control in the Great Lakes is the use of the piscicide, 3-trifluoromethyl-4-nitrophenol (TFM), which is applied to streams containing larval sea lampreys. However, TFM effectiveness can be influenced by abiotic factors such as pH and temperature, which fluctuate daily and seasonally. The objectives of this thesis were to evaluate the influence of pH, temperature, and season on the toxicity, uptake, and elimination of TFM by larval sea lamprey. Radio-labeled TFM (¹⁴C-TFM) was used to determine how TFM uptake rates varied at different water pHs or temperatures during exposure to …

A Missing Link In The Ionoregulatory Strategy Of Larval Sea Lamprey (Petromyzon Marinus) And African Lungfish (Protopterus Annectens): A Closer Look Into The Role Of The Non-Gastric H+/K+-Atpase, Justine E. Doherty

Theses and Dissertations (Comprehensive)

Fishes living in freshwater need to actively compensate for the diffusive loss of ions and osmotic gain of water. The gill is the primary organ of ion regulation and contains an array of ion transport proteins to help maintain homeostasis. Two of the more well studied ion pumps are the Na⁺/K⁺-ATPase (NKA) and vacuolar type proton ATPase (V-ATPase). This thesis focuses on another ion pump known as the non-gastric H⁺/K⁺-ATPase (ngHKA). The ngHKA (gene: atp12a) has not been found in any of the teleost fishes, indicating loss from that lineage. In …

The Effects Of Exercise Intensity On Acylated Ghrelin, Active Glucagon-Like Peptide-1, And Appetite: Examining The Potential Involvement Of Interleukin-6, Hashim Islam

Theses and Dissertations (Comprehensive)

Interleukin-6 (IL-6) stimulates the release of appetite-regulating hormones in animals and associates with decreased energy intake in humans. Thus, IL-6 may contribute to the intensity- dependent effects of exercise on appetite-related parameters. The purpose of this study was to examine the effects of exercise intensity on IL-6, appetite-regulating hormones, and appetite perceptions. Eight active young males completed four sessions: 1) Moderate-intensity continuous training (MICT; 30 min running, 65% VO2max); 2) High-intensity continuous training (HICT; 30 min running, 85% VO2max); 3) Sprint interval training (SIT; 4 x 30 sec “all-out” running bouts separated by 4 min recovery); 4) Control (CTRL; no …

Understanding The Physiological Effects Of Suspended Material On Rainbow Trout (Oncorhynchus Mykiss), Tyler J. Weinhardt

Theses and Dissertations (Comprehensive)

The effect of global warming on northern environments is becoming increasingly evident. Melting of underlying permafrost is associated with widespread impacts in these environments. The loss of permafrost results in a destabilizing of underlying sedimentary layers resulting in thermokarst slumping. When this occurs on a large scale (mega-slumping) soil material becomes mobilized and is carried into local streams and rivers. The purpose of this study is to examine the sub-lethal physiological effects that suspended material has on rainbow trout (Oncorhynchus mykiss) in the context of the Peel River Plateau. Juvenile rainbow trout were exposed (following Environment Canada exposure …

The Effects Of Lampricide 3-Trifluoromethyl-4-Nitrophenol Toxicity On The Gills Of Larval Sea Lamprey And Non-Target Rainbow Trout And Lake Sturgeon, Lisa A. Sorensen

Theses and Dissertations (Comprehensive)

The pesticide, 3-trifluoromethyl-4-nitrophenol (TFM), is widely used in the Great Lakes to control invasive sea lampreys (Petromyzon marinus) populations, but much about its sub-lethal effects remains unknown. A better understanding of its toxicity is needed to improve TFM effectiveness and to protect non-target organisms from its potential adverse effects. The objectives of this thesis were to test the following two hypotheses: (1) impairment of mitochondrial ATP production by TFM interferes with ATP-dependent ion-uptake by fish, leading to altered electrolyte balance, and (2) perturbations of gill function by TFM are exacerbated in soft, ion poor water (SW; 40 mg …

Estimates Of Persistent Inward Current In Human Motor Neurons During Postural Sway, Ryan Foley, Jayne M. Kalmar Dr.

Theses and Dissertations (Comprehensive)

Persistent inward current (PIC) is a membrane property critical for increasing gain of motor neuron output. In humans, most estimates of PIC are made from plantarflexor or dorsiflexor motor units with the participant in a seated position with the knee flexed. This seated and static posture neglects the task-dependent nature of the monoaminergic drive that modulates PIC activation. Seated estimates may drastically underestimate the amount of PIC that occurs in human motor neurons during functional movement. The current study estimated PIC using the conventional paired motor unit technique which uses the difference between reference unit firing frequency at test unit …

Distribution And Elimination Of 3-Trifluoromethyl-4-Nitrophenol (Tfm) By Sea Lamprey (Petromyzon Marinus) And Non-Target, Rainbow Trout (Oncorhynchus Mykiss) And Lake Sturgeon (Acipenser Fulvescens), Michael W. Le Clair

Theses and Dissertations (Comprehensive)

The pesticide, 3-trifluoromethyl-4-nitrophenol (TFM), has been highly successful in the control of sea lamprey (Petromyzon marinus) populations in the Great Lakes. Treatments with TFM involve applying it to streams, where it targets larval sea lamprey which live burrowed in the stream substrate. While the toxic mechanism of TFM has been elucidated, and its effects on sea lamprey described, its effects on non-target fish species such as rainbow trout (Oncorhynchus mykiss) and lake sturgeon (Acipenser fulvescens) are not as well understood. The present work demonstrated that rainbow trout show a great capacity to detoxify the lampricide using glucuronidation, when exposed to …

Mechanisms Of Nitrogenous Waste Excretion During The Complex Life Cycle Of The Sea Lamprey (Petromyzon Marinus), James M. Neal Mr.

Theses and Dissertations (Comprehensive)

Sea lampreys (Petromyzon marinus) are a phylogenetically ancient jawless fish, with a multi-staged life cycle characterized by a prolonged suspension-feeding larval stage, which is followed by metamorphosis into parasitic lampreys that feed on the protein-rich blood of fishes. The switch from a nutrient poor to protein-rich diet in the sea lamprey is associated with an increased capacity to deaminate excess amino acids and to excrete ammonia and urea following metamorphosis. The focus of this thesis was to determine if changes in nitrogenous waste transporter protein abundance facilitate ammonia and urea excretion during different stages of the sea lamprey …

Physiological & Cellular Mechanisms Of Ammonia Tolerance In The Goldfish (Carassius Auratus), Sanya Sidhu

Theses and Dissertations (Comprehensive)

Ammonia may increase in the blood and tissues of fishes following feeding or exposure to high concentrations of environmental ammonia arising from the degradation of organic matter in aquatic environments, sewage effluent, and run-off from landfills. Ammonia may be detoxified using the enzyme glutamine synthetase (GS), which catalyzes the conversion of ammonia to glutamine. It has been suggested, however that build-ups of glutamine within the astrocytes of the brain can cause brain swelling by increasing intracellular osmolarity and water uptake by the cells. Using in vivo and in vitro approaches, the goal of this thesis was to determine if: (i) …

The Effect Of Cadmium Exposure On Repeat Swimming Performance And Recovery In Rainbow Trout (Oncorhynchus Mykiss), Brown Trout (Salmo Trutta) And Lake Whitefish (Coregonus Clupeaformis), Jessie L. Cunningham

Theses and Dissertations (Comprehensive)

Swim performance provides a measure of the integrated metabolic costs of sub-lethal exposure to stressors, including Cd. While the impacts to sustained swimming performance in Cd exposed fish have already been characterised, effects to repeat swimming ability have not. This thesis identifies the effects of sub-lethal waterborne Cd exposure on ionoregulatory function, repeat swimming ability, anaerobic metabolism and stress response in rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis).

Repeat swim trials included an initial swim to 85% of the U_crit of control fish and a recovery period …

Effects Of 17Α-Ethinylestradiol (Ee2) On Reproductive Endocrine Status In Mummichog (Fundulus Heteroclitus) Under Differing Salinity And Temperature Conditions, Esteban Gillio Meina

Theses and Dissertations (Comprehensive)

Waterborne exposure to 17α-ethinylestradiol (EE₂), a synthetic estrogen, has previously been shown to decrease reproductive endocrine status in the estuarine killifish or mummichog (Fundulus heteroclitus macrolepidotus; northern subspecies). To evaluate if variations in salinity or temperature holding conditions modify the effects of EE₂ on gonad size, plasma reproductive steroid levels, and gonadal steroidogenesis, mummichog were exposed in vivo for 14 days to 0, 50 and 250 ng/L EE₂ in 0, 16 and 32 ppt salinity at 18°C and to 0 and 250 ng/L EE₂ at 10, 18 and 26°C at 16 ppt salinity. …