Physiology Commons^™

The Many Side Jobs Of Lateral Suppressor (Ls) In Plant Development, Janlo M. Robil

Biology Faculty Publications

No abstract provided.

Is The Nucleus The Unwitting Architect Of Asymmetric Cell Division In Plants?, Janlo M. Robil

Biology Faculty Publications

No abstract provided.

Timekeeper's Dilemma: How Photo-Thermal Cues Alter Flowering Duration, Kyle W. Swentowsky, Janlo M. Robil

Biology Faculty Publications

No abstract provided.

In Vivo Potentiation Of Muscle Torque Is Enhanced In Female Mice Through Estradiol-Estrogen Receptor Signaling, Gengyun Le, Cory W. Baumann, Dawn A. Lowe, Gordon L. Warren

Biology Faculty Publications

Estradiol affects several properties of skeletal muscle in females including strength. Here, we developed an approach to measure in vivo posttetanic twitch potentiation (PTP) of the anterior crural muscles of anesthetized mice and tested the hypothesis that 17b-estradiol (E2) enhances PTP through estrogen receptor (ER) signaling. Peak torques of potentiated twitches were 40%–60% greater than those of unpotentiated twitches and such PTP was greater in ovary-intact mice, or ovariectomized (Ovx) mice treated with E2, compared with Ovx mice (P < 0.047). PTP did not differ between mice with and without ERa ablated in skeletal muscle fibers (P = 0.347). Treatment of ovary-intact and Ovx mice with ERb antagonist and agonist (PHTPP and DPN, respectively) did not affect PTP (P = 0.258). Treatment with G1, an agonist of the G protein-coupled estrogen receptor (GPER), significantly increased PTP in Ovx mice from 41 ± 10% to 66 ± 21% (means ± SD; P = 0.034). Collectively, these data indicate that E2 signals through GPER, and not ERa or ERb, in skeletal muscles of female mice to augment an in vivo parameter of strength, namely, PTP.

Ca2+ Entry Units In A Superfast Fish Muscle, James Matthew Kittelberger, Clara Franzini-Armstrong, Simona Boncompagni

Biology Faculty Publications

Over the past two decades, mounting evidence has demonstrated that a mechanism known as store-operated Ca2+ entry (SOCE) plays a crucial role in sustaining skeletal muscle contractility by facilitating Ca2+ influx from the extracellular space during sarcoplasmic reticulum (SR) Ca2+ depletion. We recently demonstrated that, in exercised fast-twitch muscle from mice, the incidence of Ca2+ entry units (CEUs), newly described intracellular junctions between dead-end longitudinal transverse tubular (T-tubule) extensions and stacks of sarcoplasmic reticulum (SR) flat cisternae, strictly correlate with both the capability of fibers to maintain contractions during fatigue and enhanced Ca2+ influx via SOCE. Here, we tested the …

Navigating The “Covid Hangover” In Physiology Courses, Jennifer E. Schaefer

Biology Faculty Publications

Undergraduate educators and students must navigate lingering aftereffects of the COVID pandemic on education in the 2021–2022 academic year even as COVID continues to impact delivery of undergraduate science education. This article describes ongoing difficulties for undergraduate science, technology, engineering, and mathematics (STEM) students and educators and suggests strategies and easy-to-use resources that may help educators navigate the “COVID hangover” and ongoing COVID-related disruptions.

Rapid And Direct Action Of Lipopolysaccharide (Lps) On Skeletal Muscle Of Larval Drosophila, Rachel Potter, Alexis Meade, Samuel Potter, Robin L. Cooper

Biology Faculty Publications

The endotoxin lipopolysaccharide (LPS) from Gram-negative bacteria exerts a direct and rapid effect on tissues. While most attention is given to the downstream actions of the immune system in response to LPS, this study focuses on the direct actions of LPS on skeletal muscle in Drosophila melanogaster. It was noted in earlier studies that the membrane potential rapidly hyperpolarizes in a dose-dependent manner with exposure to LPS from Pseudomonas aeruginosa and Serratia marcescens. The response is transitory while exposed to LPS, and the effect does not appear to be due to calcium-activated potassium channels, activated nitric oxide synthase …

Temperature Regulation Of Plant Hormone Signaling During Stress And Development, Christian Castroverde, Damaris Dina

Biology Faculty Publications

Global climate change has broad-ranging impacts on the natural environment and human civilization. Increasing average temperatures along with more frequent heat waves collectively have negative effects on cultivated crops in agricultural sectors and wild species in natural ecosystems. These aberrantly hot temperatures, together with cold stress, represent major abiotic stresses to plants. Molecular and physiological responses to high and low temperatures are intricately linked to the regulation of important plant hormones. In this review, we shall highlight our current understanding of how changing temperatures regulate plant hormone pathways during immunity, stress responses and development. This article will present an overview …

Data Associated With Walter-Mcneill Et Al. (2021) Oecologia Https://Doi.Org/10.1007/S00442-021-05038-Y, Barry Logan

Biology Faculty Publications

No abstract provided.

Circadian Disruption With Constant Light Exposure Exacerbates Atherosclerosis In Male Apolipoproteine-Deficient Mice, Jeffrey M. Chalfant, Deborah A. Howatt, Lisa R. Tannock, Alan Daugherty, Julie S. Pendergast

Biology Faculty Publications

Disruption of the circadian system caused by disordered exposure to light is pervasive in modern society and increases the risk of cardiovascular disease. The mechanisms by which this happens are largely unknown. ApolipoproteinE-deficient (ApoE^−/−) mice are studied commonly to elucidate mechanisms of atherosclerosis. In this study, we determined the effects of light-induced circadian disruption on atherosclerosis in ApoE^−/− mice. We first characterized circadian rhythms of behavior, light responsiveness, and molecular timekeeping in tissues from ApoE^−/− mice that were indistinguishable from rhythms in ApoE^+/+ mice. These data showed that ApoE^−/− mice had no inherent circadian …

The Effects Of Bacterial Endotoxin Lps On Synaptic Transmission At The Neuromuscular Junction, Robin L. Cooper, Micaiah Mcnabb, Jeremy Nadolski

Biology Faculty Publications

The direct action of bacterial lipopolysaccharides (LPS) endotoxin was shown to enhance synaptic transmission and hyperpolarize the membrane potential at low doses, but block glutamatergic receptors and decrease observable spontaneous events at a high dosage. The dosage effects are LPS type specific. The hyperpolarization is not due to voltage-gated potassium channels or to activation of nitric oxide synthase (NOS). The effects are induced directly by LPS, independent of an immune response.

Alternative Nad(P)H Dehydrogenase And Alternative Oxidase: Proposed Physiological Roles In Animals, Allison Mcdonald, Dmytro V. Gospodaryov

Biology Faculty Publications

The electron transport systems in mitochondria of many organisms contain alternative respiratory enzymes distinct from those of the canonical respiratory system depicted in textbooks. Two of these enzymes, the alternative NADH dehydrogenase and the alternative oxidase, were of interest to a limited circle of researchers until they were envisioned as gene therapy tools for mitochondrial disease treatment. Recently, these enzymes were discovered in several animals. Here, we analyse the functioning of alternative NADH dehydrogenases and oxidases in different organisms. We propose that both enzymes ensure bioenergetic and metabolic flexibility during environmental transitions or other conditions which may compromise the operation …

Identification Of The Alternative Oxidase Gene And Its Expression In The Copepod Tigriopus Californicus, Allison Mcdonald, Carly E. Tward, Willie Cygelfarb, Jaspreet Singh

Biology Faculty Publications

In addition to the typical electron transport system (ETS) in animal mitochondria responsible for oxidative phosphorylation, in some species there exists an alternative oxidase (AOX) pathway capable of catalyzing the oxidation of ubiquinol and the reduction of oxygen to water. The discovery of AOX in animals is recent and further investigations into its expression, regulation, and physiological role have been hampered by the lack of a tractable experimental model organism. Our recent DNA database searches using bioinformatics revealed an AOX sequence in several marine copepods including Tigriopus californicus. This species lives in tidepools along the west coast of North …

Associative Learning Contributes To The Increased Water Intake Observed After Daily Injections Of Angiotensin Ii, Maggie Postolache, Jessica Santollo, Derek Daniels

Biology Faculty Publications

Daily injections of angiotensin II (AngII) cause a progressive increase of water intake that resembles a classically ascribed non-associative sensitization. Consistent with the presumption that the observed increase in intake was sensitization, we hypothesized that it resulted from a pharmacological interaction between AngII and its receptor. To test this hypothesis, and remove the influence of drinking itself, we implemented a delay in water access after injection of AngII (icv) on four consecutive ‘induction days,’ and then measured intake on the next day (‘test day’) when rats were allowed to drink immediately after AngII. The delay in water access effectively reduced …

Macrophages Are Necessary For Epimorphic Regeneration In African Spiny Mice, Jennifer Simkin, Thomas R. Gawriluk, John C. Gensel, Ashley W. Seifert

Biology Faculty Publications

How the immune system affects tissue regeneration is not well understood. In this study, we used an emerging mammalian model of epimorphic regeneration, the African spiny mouse, to examine cell-based inflammation and tested the hypothesis that macrophages are necessary for regeneration. By directly comparing inflammatory cell activation in a 4 mm ear injury during regeneration (Acomys cahirinus) and scarring (Mus musculus), we found that both species exhibited an acute inflammatory response, with scarring characterized by stronger myeloperoxidase activity. In contrast, ROS production was stronger and more persistent during regeneration. By depleting macrophages during injury, we demonstrate …

High-Fat Feeding Does Not Disrupt Daily Rhythms In Female Mice Because Of Protection By Ovarian Hormones, Brian T. Palmisano, John M. Stafford, Julie S. Pendergast

Biology Faculty Publications

Obesity in women is increased by the loss of circulating estrogen after menopause. Shift work, which disrupts circadian rhythms, also increases the risk for obesity. It is not known whether ovarian hormones interact with the circadian system to protect females from obesity. During high-fat feeding, male C57BL/6J mice develop profound obesity and disruption of daily rhythms. Since C57BL/6J female mice did not develop diet-induced obesity (during 8 weeks of high-fat feeding), we first determined if daily rhythms in female mice were resistant to disruption from high-fat diet. We fed female PERIOD2:LUCIFERASE mice 45% high-fat diet for 1 week and measured …

Effects Of Echinostoma Trivolvis Metacercariae Infection During Development And Metamorphosis Of The Wood Frog (Lithobates Sylvaticus), Sarah A. Orlofske, Lisa K. Belden, William A. Hopkins

Biology Faculty Publications

Many organisms face energetic trade-offs between defense against parasites and other host processes that may determine overall consequences of infection. These trade-offs may be particularly evident during unfavorable environmental conditions or energetically demanding life history stages. Amphibian metamorphosis, an ecologically important developmental period, is associated with drastic morphological and physiological changes and substantial energetic costs. Effects of the trematode parasite Echinostoma trivolvis have been documented during early amphibian development, but effects during later development and metamorphosis are largely unknown. Using a laboratory experiment, we examined the energetic costs of late development and metamorphosis coupled with E. trivolvis infection in wood …

Sine-Wave Electrical Stimulation Initiates A Voltage-Gated Potassium Channel-Dependent Soft Tissue Response Characterized By Induction Of Hemocyte Recruitment And Collagen Deposition, Brandon M. Franklin, Eleni Maroudas, Jeffrey L. Osborn

Biology Faculty Publications

Soft tissue repair is a complex process that requires specific communication between multiple cell types to orchestrate effective restoration of physiological functions. Macrophages play a critical role in this wound healing process beginning at the onset of tissue injury. Understanding the signaling mechanisms involved in macrophage recruitment to the wound site is an essential step for developing more effective clinical therapies. Macrophages are known to respond to electrical fields, but the underlying cellular mechanisms mediating this response is unknown. This study demonstrated that low‐amplitude sine‐wave electrical stimulation (ES) initiates a soft tissue response in the absence of injury in Procambarus …

Optogenetic Stimulation Of Drosophila Heart Rate At Different Temperatures And Ca2+ Concentrations, Yuechen Zhu, Henry Uradu, Zana R. Majeed, Robin L. Cooper

Biology Faculty Publications

Optogenetics is a revolutionary technique that enables noninvasive activation of electrically excitable cells. In mammals, heart rate has traditionally been modulated with pharmacological agents or direct stimulation of cardiac tissue with electrodes. However, implanted wires have been known to cause physical damage and damage from electrical currents. Here, we describe a proof of concept to optically drive cardiac function in a model organism, Drosophila melanogaster. We expressed the light sensitive channelrhodopsin protein ChR2.XXL in larval Drosophila hearts and examined light‐induced activation of cardiac tissue. After demonstrating optical stimulation of larval heart rate, the approach was tested at low temperature …

Skeletal Muscle Mass And Composition During Mammalian Hibernation, Clark J. Cotton

Biology Faculty Publications

Hibernation is characterized by prolonged periods of inactivity with concomitantly low nutrient intake, conditions that would typically result in muscle atrophy combined with a loss of oxidative fibers. Yet, hibernators consistently emerge from winter with very little atrophy, frequently accompanied by a slight shift in fiber ratios to more oxidative fiber types. Preservation of muscle morphology is combined with down-regulation of glycolytic pathways and increased reliance on lipid metabolism instead. Furthermore, while rates of protein synthesis are reduced during hibernation, balance is maintained by correspondingly low rates of protein degradation. Proposed mechanisms include a number of signaling pathways and transcription …

Teaching Physiology Online: Successful Use Of Case Studies In A Graduate Course, Giovanni Casotti, John T. Beneski, Maureen T. Knabb

Biology Faculty Publications

No abstract provided.

High Altitude Diving In River Otters: Coping With Combined Hypoxic Stresses, Jamie R. Crait, Henry D. Prange, Noah A. Marshall, Henry J. Harlow, Clark Cotton, Merav Ben-David

Biology Faculty Publications

River otters (Lontra canadensis) are highly active, semi-aquatic mammals indigenous to a range of elevations and represent an appropriate model for assessing the physiological responses to diving at altitude. In this study, we performed blood gas analyses and compared blood chemistry of river otters from a high-elevation (2357 m) population at Yellowstone Lake with a sea-level population along the Pacific coast. Comparisons of oxygen dissociation curves (ODC) revealed no significant difference in hemoglobin-oxygen (Hb-O₂) binding affinity between the two populations - potentially because of demands for tissue oxygenation. Instead, high-elevation otters had greater Hb concentrations (18.7 …

Avoidance Of Skeletal Muscle Atrophy In Spontaneous And Facultative Hibernators, Clark Cotton, Henry J. Harlow

Biology Faculty Publications

Smooth and skeletal muscle changes were compared from overwintering white-tailed prairie dogs, spontaneous hibernators that undergo regular, low-temperature torpor bouts, and black-tailed prairie dogs, facultative hibernators that use sporadic, moderate-temperature torpor bouts. The objectives were to assess the abilities of these two species with dramatically different torpor patterns (1) to conserve skeletal muscle morphology, protein, and strength and (2) to use labile protein in the small intestine and liver during the winter season of reduced activity and food intake. Mass and protein concentration of the extensor digitorum longus (EDL), soleus, liver, and small intestine, as well as skeletal muscle strength …

The Effects Of Fluorescent Tracking Powder On Oxygen Consumption In Salamanders Using Either Cutaneous Or Bimodal Respiration, Sarah A. Orlofske, Kristine L. Grayson, William A. Hopkins

Biology Faculty Publications

Fluorescent powder is gaining attention as an effective method for tracking terrestrial amphibian movements, particularly for species that are too small for conventional tracking equipment. The technique requires coating portions of an animal with fluorescent powder, releasing the animal, and following the trail of powder as it is progressively lost during movement. Recent studies have shown that fluorescent powder has no negative effects on survival or growth. However, a substance that coats the skin, a major respiratory organ in most amphibians, may have sublethal effects on performance and consequently behavior. We tested the effect of fluorescent powder application on the …

Do Hypothermic Tissue Tolerances Limit Torpor Expression?, Clark J. Cotton, Henry J. Harlow

Biology Faculty Publications

1. Arrest temperatures and Q₁₀ values for extensor digitorum longus (EDL), soleus, trabecula, and jejunum muscle twitch strength, contraction time, and 0.5 relaxation time were calculated for a deep torpor hibernator, white-tailed prairie dog (WTPD) (Cynomys leucurus), a shallow torpor hibernator, black-tailed prairie dog (BTPD) (Cynomys ludovicianus), and a non-hibernator, lab rat (Rattus norvegicus) to test the hypothesis that tissue temperature tolerances limit the depth of expressed torpor.

2. There were no temperature tolerance differences between the tissues of the two species of hibernators. Both hibernating species had arrest temperatures and Q_{10 …}

Successful Implementation Of Inquiry-Based Physiology Laboratories In Undergraduate Major And Nonmajor Courses, Giovanni Casotti, Loretta Rieser-Danner, Maureen T. Knabb

Biology Faculty Publications

No abstract provided.

Spots Of Adult Male Red-Spotted Newts Are Redder And Brighter Than In Females: Evidence For A Role In Mate Selection?, Andrew K. Davis, Kristine L. Grayson

Biology Faculty Publications

As aquatic adults, eastern red-spotted newts (Notophthalmus v. viridescens) are generally green with two rows of dorsal spots, which vary in number between individuals and range in colour from orange to red. The function of these spots is unknown, but it is possible that they serve as sexual ornamentations and we examined this hypothesis by testing for sexual dimorphism in spot characteristics. We used an image analysis approach that has been used previously with this and other amphibian species to compare the number, size and colour – redness (hue score) and brightness – of spots in 100 male …

Assembly Of Α4Β2 Nicotinic Acetylcholine Receptors Assessed With Functional Fluorescently Labeled Subunits: Effects Of Localization, Trafficking, And Nicotine-Induced Upregulation In Clonal Mammalian Cells And In Cultured Midbrain Neurons, Raad Nashmi, Mary E. Dickinson, Sheri Mckinney, Mark Jareb, Cesar Labarca, Scott E. Fraser E. Fraser, Henry A. Lester

Biology Faculty Publications

Fura-2 recording of Ca²⁺ influx was used to show that incubation in 1 μM nicotine (2–6d) upregulates several pharmacological components of acetylcholine (ACh) responses in ventral midbrain cultures, including a MLA-resistant, DHβE-sensitive component that presumably corresponds to α4β2 receptors. To study changes in α4β2 receptor levels and assembly during this upregulation, we incorporated yellow and cyan fluorescent proteins (YFPs and CFPs) into the α4 or β2 M3–M4 intracellular loops, and these subunits were coexpressed in human embryonic kidney (HEK) 293T cells and cultured ventral midbrain neurons. The fluorescent …

Rapping To Review: A Novel Strategy To Engage Students And Summarize Course Material, Maureen T. Knabb

Biology Faculty Publications

No abstract provided.