Research Methods in Life Sciences Commons^™

Tracing Nutrient Sources To Lipid Production In Insects Using Stable Isotope (Δ13c, Δ2h) Tracers: Implications For Nutritional Physiology Of Migratory Species., Libesha Anparasan, Keith A. Hobson

Western Research Forum

Using stable isotope measurements of insect tissues to determine origin and migratory patterns is well established. However, isotopically determining nutritional origins of lipids, the primary fuel of migration, has not been as thoroughly researched. We explored isotopic links between diet and stored lipids in laboratory raised True armyworm moths (Mythimna unipuncta) using δ¹³C and δ²H measurements. Pupae were randomly separated into four groups (n=20) and fed isotopically distinct nectar, each consisting of a combination of high δ¹³C (C4 sugar), or low δ¹³C (C3 sugar) carbohydrate, with high δ²H (deuterium spiked), …

The Effects Of Salinity On Zootechnical Performance Of Spotted Seatrout (Cynoscion Nebulosus) In Recirculating Aquaculture Systems, Eric Gigli

Master's Theses

The spotted seatrout (Cynoscion nebulosus) is a euryhaline finfish candidate for marine aquaculture in the northern Gulf of Mexico. Aquaculture of this species currently uses salinities of 25 psu or greater making production challenging in areas where high salinity water is not available. This study aimed to document the effects of salinity on zootechnical performance of spotted seatrout embryos, early larvae, and juveniles in recirculating aquaculture systems to assist with the development of protocols for low salinity culture.

Embryos obtained from a volitional spawn at 29 psu were incubated at three salinities (12.5, 18.75, or 25 psu) until …

Comparative Thermal Ecology Of Coastal And Inland Pacific Rattlesnakes (Crotalus Oreganus), Hayley Layne Crowell

Master's Theses

Global biodiversity is declining as a direct result of anthropogenic climate change. Ectothermic species have become focal organisms for studying the ecological effects of altered climates due to the clear relationship between environmental temperatures and ectotherms’ basic physiological functions. Historically, examinations of these effects have focused heavily on heliothermic lizards, and most others have tended to focus on single populations or sympatric species within a single community. Addressing the longterm energetic implications of environmental temperature variation will provide valuable insight into the cascading physiological effects that certain populations or species may experience as a result of altered climates.

In this …

Heat Exposure And Hypohydration Exacerbate Physiological Strain During Load Carrying, Elizabeth L. Adams, Douglas J. Casa, Robert A. Huggins, Julie K. Demartini, Rebecca L. Stearns, Rachel M. Kennedy, Lindsay J. Distefano, Lawrence E. Armstrong, Carl M. Maresh

All PTHMS Faculty Publications

Heat exposure and hypohydration induce physiological and psychological strain during exercise; however, it is unknown if the separate effects of heat exposure and hypohydration are synergistic when co-occurring during loaded exercise. This study compared separate and combined effects of heat exposure and hypohydration on physiological strain, mood state, and visual vigilance during loaded exercise. Twelve males (mean±SD; age, 20±2 years; body mass, 74.0±8.2 kg; maximal oxygen uptake, 57.0±6.0 mLkg-1min-1) completed 4 trials under the following conditions: euhydrated temperate (EUT), hypohydrated temperate (HYT), euhydrated hot (EUH), and hypohydrated hot (HYH). Exercise was 90 min of treadmill walking (∼50% VO2 max, 5% …

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 …

Cold Tolerance, Temperature Mediated Discontinuous Gas Exchange, And Emergence Of The Blue Orchard Mason Bee (Osmia Lignaria), Logan Kral

All Master's Theses

The relationship between low temperatures, emergence and supercooling point of Osmia lignaria were the subject of this study. One hundred sixty-eight bees were subjected to 5 pre-wintering temperature treatments (two constant temperature controls - 22^oC, 14^oC, one of which with and one without a 12h photoperiod, and three 12h:12h thermoperiod treatments – 14:10^oC, 14:5^oC, and 14:0^oC) and were then evaluated in terms of emergence time and post-emergence vigor. An additional 70 bees were tested for metabolic rate and discontinuous gas exchange in response to test temperature conditions. An additional sample …

An Exploratory Study Of Extremesport Athletes’ Nature Interactions:From Well-Being To Pro-Environmental Behavior, Tadhg Eoghan Macintyre, Andree M. Walkin, Juergen Beckmann, Giovanna Calogiuri, Susan Gritzka, Greig Oliver, Aoife Donnelly, Giles Warrington

Articles

Traditionally, perceptions about extreme sport athletes being disconnected fromnature and a risk-taking population have permeated the research literature. Drawingupon theoretical perspectives from environmental, sport, organizational and positivepsychology, this qualitative study attempts to explore the lived experiences of fourmale and four female extreme sport athletes. The purpose of this study was togain insight and understanding into the individuals’ attitudes toward the benefits ofextreme sport activities for well-being, resilience and pro-environmental behavior. Eightparticipants (Mean age = 40.5 years;SD=±12.9) provided written informed consentto partake in semi-structured interviews. Each athlete provided written consented toallow the publication of their identifiable data and in order to …

Molecular Targets Of Psychedelics And Their Role In Behavioral Models Of Hallucinogenic Action, Hiba Z. Vohra

Theses and Dissertations

Psychedelics are a subset of hallucinogenic drugs that exert their characteristic effects through agonist activity at the serotonin receptor 2A (5-HT_2A). In this study, I aimed to characterize the modulatory role of the metabotropic glutamate subtype 2 receptor (mGluR2) in the 5-HT_2A-specific rodent model of hallucinogenic action, head-twitch response (HTR). Secondly, I aimed to explore if 5-HT_2A agonist-induced deficits in prepulse inhibition (PPI) of the startle response, an additional model of hallucinogenic action, could be produced in mice. Though 5-HT_2A agonist-induced PPI deficits, which represent interruptions in normal sensorimotor gating, have been described in …

Targeting Neuropeptides To Bone Fractures For Accelerated Healing, Nicholas A. Young, Jeffery J. Nielsen, Philip S. Low

The Summer Undergraduate Research Fellowship (SURF) Symposium

In patients over the age of 65 especially, bone fractures represent a significant disease burden. Non-invasive drug therapies are not available for bone fractures which represents a problem for this population. Vasoactive intestinal peptide (VIP) and Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP), two neuromodulator peptides in the glucagon superfamily, have demonstrated positive regulation of osteoblast proliferation and activity. Using acidic oligopeptides, we have developed ligands that target to and accumulate at fracture sites. These targeting ligands can be synthesized in sequence with bone anabolic peptides to minimize off target effects and increase potency at the fracture site to create safer and …

Pyruvate Kinase Isoform M2 Influences Autophagy And Related Processes In Hepatocellular Carcinoma Cells, Matthew Lin

University Scholar Projects

Hepatocellular carcinoma (HCC) is the most common form of liver cancer that affects ~14 million people in the world. Like all cancers, HCC is a disease that arises from unstinted cellular growth initiated by genetic alterations, metabolic changes, and dysregulation in key cellular pathways. Of interest is the relationship between metabolism and cell proliferation/degradation for therapeutic targeting. Pyruvate kinase M2 is a dimeric, glycolytically inactive isoform of the final enzyme involved in glycolysis, that is often upregulated in cancerous tissue. It is thought that the enzymatic function of PKM2 outside of glycolysis contributes to the biosynthesis of anabolic intermediates used …

Targeted Limb Heating Augments The Actions Of Igf1 In The Growth Plate And Increases Bone Elongation In Growing Mice, Holly Lyn Racine

Theses, Dissertations and Capstones

Bone elongation disorders can lead to painful musculoskeletal disabilities in adulthood. Existing treatment options to correct left-right asymmetry in limb length include invasive surgeries and/or drug regimens. These are often only partially effective. Previous studies in weanling mice have shown that a daily application of mild heat (40°C) to limbs on one side of the body could be used to noninvasively enhance bone elongation. However, the impact of heat-treatment on bone at the cellular level remains elusive. The epiphyseal growth plate, the band of cartilage located at each end of long bones, is the main site of longitudinal growth and …

Behavioral Responses To Pulses Of Light In The Longfin Inshore Squid, Doryteuthis Pealeii (Lesueur, 1821), Stavros P. Hadjisolomou

Dissertations, Theses, and Capstone Projects

The coleoid cephalopods (octopus, squid, and cuttlefish) are masters of rapid, adaptive camouflage. Unlike the slower hormonal chromatophore control of flatfish and chameleons, coleoid mollusks can change body patterns in milliseconds. Visual camouflage in coleoids is driven by a sensorimotor system consisting of visual input of their surroundings, a sophisticated central nervous system for information processing, and a neuromuscular control for body patterning. Motor neurons selectively activate millions of muscles, alternately expanding and reducing the pigmented chromatophores to generate visible brown, red, orange and yellow patterns on the skin. Below the chromatophore-layered skin are two types of reflecting cells, iridophores …

Proteomic Analysis Of The Crustacean Molting Gland (Y-Organ) Over The Course Of The Molt Cycle, Talia B. Head

Master's Theses

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 the molting hormones, ecdysteroids, by the YO. Analysis of gene expression in the XOs and YOs has led to the development of a proposed molecular signaling pathway which regulates ecdysteroidogenesis and subsequent molting in crustaceans. In this study, changes in protein abundance in the YO were characterized over the course of a molt cycle (intermolt, early premolt, mid premolt, …

The Effect Of Ambient Temperature On Recovery Of Surgical Stress In Sprague-Dawley Rats, Romie D. Powell

Masters Theses, 2010-2019

Laboratory animals are housed at ambient temperatures ranging from 20°C – 26°C per recommended guidelines. Rats in particular typically prefer ambient temperatures (Tamb) of ~27°C (Brown et al, 2011). When rats undergo surgical instrumentation for experimental use, they often recover at normal room temperature (~21°C). While this is comfortable to those maintaining them, it may lead to a cold thermal stress for the rats. It is hypothesized that housing rats at ambient temperatures away from their preferred Tamb could lead to a thermal stress, which adversely affects surgical recovery. To address this, rats (220g-350g) were surgically instrumented with a radiotelemetry …

Effect Of Prior Trauma Exposure On Alpha Amplitude, Heart Rate, And Self-Reported Negative Affect, Gina L. Denoble

All Master's Theses

This study was conducted to investigate whether the number of traumatic events an individual has previously experienced influences that individual’s physiological and psychological reactions when exposed to a negative affective stimulus followed by a mindfulness-based stress reduction (MBSR) intervention. Twenty-eight participants were placed into intact quasi-experimental groups based on their scores on the Traumatic Life Events Questionnaire (TLEQ). The negative affective stimulus consisted of a series of photos bearing negative affective valence. The photos were selected from the International Affective Picture System (IAPS), and paralleled the areas of trauma exposure evaluated by the TLEQ. All participants were exposed to the …

Behavior And Physiology Of Hermit Crabs During Burial: Shell Abandonment And Lactate Accumulation, Janelle Allison Shives

Loma Linda University Electronic Theses, Dissertations & Projects

Organisms living in the intertidal zone must adapt to environmental and physical stressors. One physical stressor that these organisms may face, and that may require specific behavioral and physiological responses, is burial by sediment. In this thesis I report the results of experiments in which I subjected the intertidal hermit crab, Pagurus samuelis, to burial and analyzed aspects of subsequent behavior and physiology. In the first set of experiments, hermit crabs were buried with the shell aperture facing either up or down, and at one of three depths (2, 4, or 6 cm). The factors hermit crab weight, shell …

Role Of No In The Regulation Of Cortisol Synthesis In Long-Term Hypoxic Sheep Fetal Adrenal, Tshepo Rothi Monau

Loma Linda University Electronic Theses, Dissertations & Projects

Our laboratory has demonstrated that sheep fetuses adapt to long-term hypoxia (LTH) by maintaining normal level of basal plasma cortisol despite increased adrenocorticotropic hormone (ACTH). But the mechanisms involved are not fully understood. Studies have shown that nitric oxide (NO) inhibits synthesis of steroid hormones in a variety of tissues, and in different animal species. Studies also showed that hypoxia increases both expression and activity levels of the nitric oxide (NO) generating enzyme, nitric oxide synthase (NOS), in certain tissues. We have here investigated the expression level and localization of NOS isoforms in sheep fetal adrenals. We also investigated the …

Anti-Inflammatory Effects Of Ppar-Gamma In Surgical Brain Injury (Sbi), Amy Hyong

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Brain injury can be caused by neurosurgical procedures themselves, due to direct trauma, retractor stretch, intraoperative hemorrhage and electrocautery damage. As a result of this surgical brain injury (SBI) postoperative complications such as inflammation, brain edema, and cell death can occur in the susceptible brain areas. Cerebral inflammation is a known contributor to the pathophysiology of brain injury. Following brain injury, the release of inflammatory mediators facilitates the development of BBB breakdown, cerebral edema, oxidative stress and neuronal death, resulting in further tissue damage in the brain and poor neurological outcomes. This study evaluates whether the use of a …

Neuronal Connections From The Cervix To The Spinal Cord Before Parturition, Mary Medina Groves

Loma Linda University Electronic Theses, Dissertations & Projects

By the day before birth, the density of nerve fibers in the cervix has increased compared to earlier in pregnancy or in nonpregnant mice. Similar findings are reported in parturient women. To test the hypothesis that connections between the cervix and spinal cord are enhanced by term, the cervix of nonpregnant and time-dated pregnant mice (day 15 or 18 post-breeding) was injected with pseudorabies virus (PRV), a trans-synaptic retrograde neural tract tracer. Mice were euthanized and perfused 5 days later. The spinal cord and cervix were removed and postfixed overnight, immersed in sucrose, and cryostat sections through the thoracic to …

Maturational Changes In Cerebrovascular Thick- And Thin-Filament Regulation, Renan Joel Sandoval

Loma Linda University Electronic Theses, Dissertations & Projects

The present study focused on the main hypothesis that age-related changes in myofilament Ca²⁺ sensitivity involve simultaneous changes in the relations between cytosolic Ca²⁺ transients, myosin phosphorylation, and force development. To define the effects of late fetal and early postnatal maturation, parallel experiments were carried out using cerebral arteries from both term lamb fetuses (140-141 days of gestation) and nonpregnant adult sheep. Fetal and adult cerebral arteries were stimulated by either mechanically, electromechanically, and/or pharmacomechanically-induced contractions, and the relations of cytosolic Ca²⁺, MLC phosphorylation, and contractile tensions were measured. These measurements allowed for stimulus and age-dependent …

Mechanisms Of Hbo-Induced Neuroprotection In A Neonatal Hypoxia-Ischemia Model, John Winter Calvert

Loma Linda University Electronic Theses, Dissertations & Projects

With an incidence approaching 1/4000 live births and as high as 60% in low birth weight infants, cerebral hypoxia-ischemia during the perinatal period is the single most important cause of acute mortality and chronic disability in newborns. Herein, we tested the hypothesis that following a hypoxic-ischemic insult hyperbaric oxygen (HBO) treatment can restore high energy metabolite levels in the affected regions of the brain and through this increase in energy levels ameliorate the spread of cell death following the insult. We also investigated if an additional mechanism by which HBO affords its neuroprotection is by altering the expression of the …

Development Of A Model For Infective Endocarditis Via Intravenous Injection And Tooth Infection Of Rats Using Pathogenic Bacteria, Shahrokh Shabahang

Loma Linda University Electronic Theses, Dissertations & Projects

Historically, focal areas of infection have been linked to a number of systemic ailments. During the early part of the 20th century, patients who were suffering from inexplicable diseases and who were suspected of having infected teeth were referred to the dentist for multiple extraction of their dentition. The discovery of antibiotics provided a false sense of security that the war against microorganisms is no longer a concern for mankind. However, more recently, it has become common belief that increasing numbers of systemic diseases are linked to chronic infections. Recovery of bacteria from representative tissues has led investigators to believe …

Chronic Hypoxia, Exercise Training, And Skeletal Muscle Capillarity: Angiogenic Regulation And Morphological Consequences, Ivan Mark Olfert

Loma Linda University Electronic Theses, Dissertations & Projects

Angiogenesis is important in health and disease. In particular, exercise training is known to increase skeletal muscle capillarity, providing there is sufficient training intensity. The stimulus for this may be intracellular hypoxia activating angiogenic growth factor gene expression. Acute hypoxia alone has been shown to increase the gene expression of several key angiogenic regulators, e.g. vascular endothelial growth factor (VEGF) and to a lesser degree transforming growth factor-β1 (TGF-β1), basic fibroblast growth factor (bFGF), and thrombospondin-1 (TSP-1), an endogenous negative angiogenic regulator. Paradoxically, however, chronic hypoxia is generally not found to increase mammalian skeletal muscle capillarity. Accordingly, we hypothesized that …

The Role Of Brn-3.2 In Retinal Ganglion Cell Differentiation, Jerin Marie Wright

Loma Linda University Electronic Theses, Dissertations & Projects

Within the retina, the POU domain of transcription factors brn-3.0, brn-3.1, and brn-3.2 are present only in retinal ganglion cells. These genes are believed to be involved in establishing neural cell lineages in mammals. In this study brn-3.2 was examined by comparing the number of ganglion cells present during postnatal development in normal mice (+/+), in mice homozygous (-/-) for the brn-3.2 gene, and in adult mice with a heterozygous gene deletion (+/-) for brn-3.2. Optic nerve cross sections were imaged by electron microscopy, and axon profiles counted systematically by hand. These counts were then related to the nerve cross …

Neuronal And Metabolic Increases In Pedunculopontine Nucleus Of Parkinson's Rats, Jonathan Dennis Carlson

Loma Linda University Electronic Theses, Dissertations & Projects

The theoretical mechanisms underlying the symptoms of Parkinson’s disease are based on dysfunctional output from the basal ganglia projected to the cortex via the thalamus. However, the subthalamic nucleus (STN) and substantia nigra pars reticularis (SNr) as part of the basal ganglia, also project to the brainstem, in particular to the pedunculopontine nucleus (PPN). Both the STN and SNr have altered neuronal activity in the 6-hydroxydopamine (6-OHDA) Parkinson’s model rat. Thus, it is hypothesized that the PPN is altered in this model of Parkinson’s disease.

This hypothesis was examined by comparing the rates of glucose metabolism and spontaneous neuronal activity …

Maternal Modulation Of Neonatal Immunity, Omar R. Fagoaga

Loma Linda University Electronic Theses, Dissertations & Projects

Although the neonatal immune system is functionally immature, immune response capabilities are not the same in all newborns. The objective of this thesis was to determine development of immunocompetence and test the hypothesis that activation of maternal inflammatory immunity during pregnancy influences maturation of the neonatal immune system.

Lymphocytes in blood and spleen were immunophenotyped by flow cytometric analysis to determine differentiation characteristics, and splenocytes were assessed for cytokine production capabilities. In normal Th2-prone outbred (CD-1) mice, an adult repertoire of naïve lymphocytes has developed by day 10 and memory cells by day 20, in blood and spleen. However, in …

Ornithine Decarboxylase And Polyamines In Perinatal Hypoxia, Satyaseelan Packianathan

Loma Linda University Electronic Theses, Dissertations & Projects

Hypoxic and hypoxic/ischemic episodes contribute to various neurological aberrations, learning disabilities, et cetera in surviving infants. Despite major advances in understanding the pathophysiology of hypoxia, the cellular basis for hypoxic-mediated injury remains poorly understood. In addition, the role of developmentally essential enzymes vis á vis their contributions, or lack thereof, to hypoxic-mediated injury has not been adequately investigated. In the series of studies comprising this dissertation, we tested the hypothesis that acute and/or chronic hypoxia affect the activity of omithine decarboxylase (ODC; E.C. 4.1.1.17), the developmentally essential enzyme in polyamine biosynthesis, in the fetal and newborn rat brain. Fetal and …

Periodontal Repair In Dogs : Evaluation Of Rhbmp-2 Carriers, Lauralee Nygaard

Loma Linda University Electronic Theses, Dissertations & Projects

This study evaluated candidate carriers for recombinant human bone morphogenic protein-2 (rhBMP-2) in periodontal reconstructive surgery.

Canine demineralized bone matrix (DBM), bovine inorganic crystallene bone matrix (Bio-Oss), bovine derived microfibrillar collagen matrix (Helistat), poly (D,L-lactide-coglycolide) micropaiticles (PLGA), and polylactic acid granules (Drilac) were used with rhBMP-2 (20 (µg/100 µl implant volume) in routine critical size canine supraalveolar periodontal defects. Contralateral defects in six beagle dogs were randomly assigned to receive: DBM/rhBMP-2, DBM-control, Bio-Oss/rhBMP-2, Helistat/rhBMP-2, PLGA/rhBMP-2, or Drilac/rhBMP-2, all with autologous blood except for Helistat and PLGA. Animals were sacrificed eight weeks post-surgery and block sections of the defects were processed …

Short And Long Term Effects Of Proton Microbeam Irradiation : In The Lateral Geniculate Nucleus Of Felis Domesticus, Chad Sherwood Reder

Loma Linda University Electronic Theses, Dissertations & Projects

Little is known of the effects of proton irradiation on neural tissue. A 1.0 mm microbeam was used on the cat lateral geniculate nucleus (LGN) to quantify the short term (< 3 months) and long term (< 9 months) effects of radiation damage. The LGN is a large structure with well defined afferent, efferent, and receptive field properties.

Electrophysiological and histological techniques were used to examine the effects of the microbeam at 60, 40, and 16 Gy, administered as a single bolus. Recordings of light evoked responses in the LGN were obtained using microelectrodes in nine animals within 12 weeks of irradiation, and 6 animals within 36 weeks of irradiation. Receptive fields were mapped onto a tangent screen using standard receptive field techniques. Histological measures included afferent …

Transforming Growth Factor-Beta 1 Expression In Developing Ovine Teeth As Visualized By In Situ Hybridization, Søren Jepsen

Loma Linda University Electronic Theses, Dissertations & Projects

Recently we demonstrated that human dentin contained relatively high amounts of transforming growth factor beta (TGF-ß) and proposed that dentin TGF-ß originated from odontoblasts. Because of the suggested role of TGF-ß in mediating cellular interactions in dental cell development by paracrine mechanisms, we studied the expression of TGF-ß message in developing teeth by in situ hybridization. 5 µm serial sections of neonatal sheep mandibular third molars that had been fixed in glutaraldehyde and paraffin-embedded were used for in situ analysis. An [³⁵S]-labeled cRNA probe, complementary to TGF-ß1 mRNA, was constructed from human TGF-ß1 cDNA. Northern analysis of total …