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Abstract: The Role Of The Novel Diguanylate Cyclase Pg_0686 In Oxidative Stress Resistance In Porphyromonas Gingivalis W83, Alexia Danielle Ximinies

Loma Linda University Electronic Theses, Dissertations & Projects

The survival/ adaptation of Porphyromonas gingivalis to the inflammatory environment of the periodontal pocket requires an ability to overcome oxidative stress. Several functional classes of genes, depending on the severity and duration of the exposure, were induced in P. gingivalis under H2O2-induced oxidative stress, including the PG0686 gene which was upregulated ca. 10-fold. In addition, its upregulation was also observed in the presence of oxygen and nitric oxide. This study is aimed to further characterize the function of this gene in response to H2O2. PG_0686, annotated as a hypothetical protein of unknown function, is a 60 kDa protein with a …

The Role Of The Filifactor Alocis Hypothetical Protein Fa1654 In Oxidative Stress Resistance, Malissa Makaylia Mangar

Loma Linda University Electronic Theses, Dissertations & Projects

The survival/adaptation of Fillifactor alocis, a fastidious gram positive asaccharolytic anaerobe in the inflammatory environment of the periodontal pocket, requires an ability to overcome oxidative stress. Moreover, emerging observations suggest its pathogenic characteristics are highlighted by its capacity to survive in the oxidative-stress microenvironment of the periodontal pocket and its likely ability to modulate the microbial community dynamics. There is still a significant gap in our understanding of F. alocis mechanism of oxidative stress resistance and its impact on the virulence and pathogenicity of the microbial biofilm. The pathogenicity of F. alocis may be impacted by its response to oxidative …

Dietary Fatty Acids And The Brain: Mechanisms Behind Neurodegeneration And Neuroprotection, Bianca Kdeiss

Loma Linda University Electronic Theses, Dissertations & Projects

The impact of dietary fat intake on cognitive function has generated growing interest as the incidence of neurodegenerative disorders continues to increase. No known cures for neurodegenerative disorders exist at this time and available pharmacological treatments are limited in their efficacy. As such, prevention and early detection have been emphasized, particularly in the context of modifiable lifestyle factors, such as diet. Despite a recognized association between dietary fat intake and cognition, limited research exists delineating the impact of different types of fat on cognitive function. In this review, research examining the association between cognition and specific dietary fatty acids—such as …

Dietary Approaches To The Treatment Of Autism Spectrum Disorders, Dhira Patel

Loma Linda University Electronic Theses, Dissertations & Projects

This chapter reviews the literature surrounding autism spectrum disorders (ASD) and their relation to gastrointestinal (GI), behavioral, neurological, and immunological functioning. Individuals with ASDs often have poor GI health, including bowel motility issues, autoimmune and/or other adverse responses to certain foods, and lack of necessary nutrient absorption. These issues may be caused or exacerbated by restrictive behavioral patterns (e.g., preference for sweet and salty foods and/or refusal of healthy foods). Those individuals with GI issues tend to demonstrate more behavioral deficits (e.g., irritability, agitation, hyperactivity) and also tend to have an imbalance in overall gut microbiome composition, thus corroborating several …

Investigating The Role Of The Three N-Terminal Hamp Domains Of The Aer2 Chemoreceptor From Pseudomonas Aeruginosa, Selina Anaya

Loma Linda University Electronic Theses, Dissertations & Projects

Pseudomonas aeruginosa is a ubiquitous environmental bacterium and opportunistic human pathogen. It readily adapts to changing environmental conditions with the aid of 26 chemoreceptors that signal to four distinct chemosensory systems. The Aer2 chemoreceptor from P. aeruginosa is an O2 sensor implicated in stress responses, virulence and fine-tuning the chemotaxis (Che) system. Aer2 is the sole chemoreceptor of the Che2 chemosensory system, which forms complexes at the cell pole during stationary phase. Aer2 is soluble, yet membrane-associated and displays an unusual arrangement with its PAS sensing domain sandwiched between three N-terminal and two C-terminal HAMP domains. HAMP domains are widespread …

Investigating The Role Of The Three N-Terminal Hamp Domains Of The Aer2 Chemoreceptor From Pseudomonas Aeruginosa, Selina Anaya

Loma Linda University Electronic Theses, Dissertations & Projects

Pseudomonas aeruginosa is a ubiquitous environmental bacterium and opportunistic human pathogen. It readily adapts to changing environmental conditions with the aid of 26 chemoreceptors that signal to four distinct chemosensory systems. The Aer2 chemoreceptor from P. aeruginosa is an O2 sensor implicated in stress responses, virulence and fine-tuning the chemotaxis (Che) system. Aer2 is the sole chemoreceptor of the Che2 chemosensory system, which forms complexes at the cell pole during stationary phase. Aer2 is soluble, yet membrane-associated and displays an unusual arrangement with its PAS sensing domain sandwiched between three N-terminal and two C-terminal HAMP domains. HAMP domains are widespread …

Strategies For Protection Of The Blood Brain Barrier In Rodent Models Of Intracerebral Hemorrhage, Derek Sunil Nowrangi

Loma Linda University Electronic Theses, Dissertations & Projects

Intracerebral Hemorrhage (ICH) is a devastating disease that causes a cascade of both mechanical and molecular injury to the central nervous system. It is a debilitating disease that has no well-established treatments, thus leaving an important area to study the pathophysiology of the disease so that new clinically translatable treatments can be found. In the development of translational treatments in experimental ICH, several challenges exist including the designing of studies, method to deliver drugs, proper dosages, and development of models. In our exploration to establish new therapies for ICH, we studied several methods and models that may help to develop …

Harnessing Blood Clot Removal Mechanisms After Germinal Matrix Hemorrhage, Jerry J. Flores

Loma Linda University Electronic Theses, Dissertations & Projects

Germinal matrix hemorrhage (GMH) is one of the leading causes of morbidity, mortality, and acquired infantile hydrocephalus in preterm infants in the United States, with little progress made in its clinical management. Blood clots have been shown to elicit secondary brain injury after GMH, by disrupting normal cerebrospinal fluid circulation and absorption after germinal matrix hemorrhage causing post-hemorrhagic hydrocephalus development. Current evidence suggests that rapid hematoma resolution is necessary to quickly improve neurological outcomes after hemorrhagic stroke. N-formyl peptide receptor 2 (FPR2), a G-protein-coupled receptor, has been shown to be neuroprotective after stroke. FPR2 activation has been associated with the …

Functional Compartmentalization Of Mlck In Fetal Arteries, Dane William Sorensen

Loma Linda University Electronic Theses, Dissertations & Projects

Changes in vascular structure and reactivity are amongst the most important that occur during the transition from fetal to newborn life, and are guided by the principle of ensuring adequate coupling of blood flow to metabolism. A clinical consequence of maladaptive fetal vascular adaptation to hypoxia is an increased probability for loss of cerebral autoregulation, increased risk for neonatal encephalopathy, and hypoxicischemic cerebral injury. MLCK is a very specific calcium-calmodulin dependent enzyme, with its only known substrate being MLC20, and is essential for the ability of VSMCs within resistance arteries to appropriately contract or relax in response to changes in …

The Effects, Perceptions, And Attitudes Of Previously Sedentary Individuals Starting An Exercise Program, Arlene Moreno, Megan Rasmussen

Loma Linda University Research Reports

Background: Many Americans do not eat healthfully or exercise, which is associated with higher risk of disease. Nutrition and exercise awareness have increased, but people experience barriers preventing lifestyle change. Limited research has been completed on the impact of nutrition education on dietary intake.

Objective: Examine whether starting an exercise program with or without nutrition education can influence dietary choices in previously sedentary individuals, and to determine their perceptions and attitudes.

Design: Mixed methods study gathering quantitative data through a food frequency questionnaire, InBody test, and demographics/exercise activity survey. Qualitative data was gathered through focus groups. Participants …

Cosyntropin As A Therapeutic Intervention Following Traumatic Brain Injury, Lorraine C. Siebold

Loma Linda University Electronic Theses, Dissertations & Projects

Traumatic brain injury (TBI) is a major health concern in the United States. With over two million occurrences and approximately 50,000 deaths annually, TBI is a leading cause of death in young adults and is associated with cognitive deficits influenced by acute and persistent neuroinflammation. Melanocortins, such as adrenocorticotropic hormone (ACTH), are agonists for melanocortin receptors located in the adrenal glands and peripheral immune cells as well as throughout the central nervous system. Melanocortins ameliorate inflammation and provide a novel therapeutic approach for TBI. The focus of this dissertation was to describe and quantify effects of cosyntropin, a synthetic ACTH …

The Sandy Bay West End Marine Reserve: Hawksbill Inhabitance And Reserve Suitability, Marsha Wright

Loma Linda University Electronic Theses, Dissertations & Projects

The hawksbill (Eretmochelys imbricata) sea turtle has been classified as critically endangered. Reductions in populations call for protective strategies, one being the implementation of protected areas. However, as a highly migratory species, preservation and restoration is difficult, as protection is required in nesting, foraging, and breeding regions. To establish adequate protected areas to aid hawksbill survival, a clear understanding of movement patterns between protected and unprotected regions is required. A foraging aggregation of juvenile hawksbills resides off the coast of Roatán, Honduras within the Sandy Bay West End Marine Reserve. The reserve is a protected area, but also spans the …

Effects Of Gestational Corticosteroids And Caloric Restriction On The Neonatal Cerebrovasculature, Naomi Franco

Loma Linda University Electronic Theses, Dissertations & Projects

The prenatal environment plays a major role in influencing the health of adult offspring. Maternal food restriction (MFR) during pregnancy is a common stressor that correlates to long-term consequences, including increased risk of cardiovascular and metabolic diseases in adult offspring. Numerous studies report persistent changes following MFR, with an emphasis on the heart and kidney. These consequences are thought to occur via programming, in which a stressor, during critical developmental windows, permanently alters the structure and function of selective fetal tissues. Furthermore, the elevation of maternal glucocorticoids associated with intrauterine stressors is a proposed mechanism of several programming events, including …

Chitosan As An Immune Modulator: Therapeutic Potential In Cerebral Amyloidopathies, Tanya Larissa Cupino

Loma Linda University Electronic Theses, Dissertations & Projects

Alzheimer’s disease (AD) and cerebral amyloid angiopathy (CAA) are neurodegenerative diseases that are pathologically defined by accumulations of amyloid beta (Aβ) in the brain parenchyma and vascular walls, respectively. CAA comorbidity occurs in more than half of advanced AD cases. Aβ can activate complement, an enzymatic cascade that terminates in a cytolytic pore called membrane attack complex (MAC). Protectin (CD59) is a GPI-anchored glycoprotein that physically interrupts formation of MAC. At autopsy, individuals with AD and CAA have high levels of MAC and normal to low levels of CD59 in the tunica media of affected blood vessels. We proposed the …

Variation In Morphology, Diet, And Venom Composition In Crotalus Pyrrhus (Cope 1867), Chip Cochran

Loma Linda University Electronic Theses, Dissertations & Projects

Because rattlesnakes rely heavily on their venom for predation and defense, we can expect selection pressures from several sources to act on its composition, including, ontogeny, sex, and environmental variation. In this dissertation, I summarize the results of four studies of the southwestern speckled rattlesnake (Crotalus pyrrhus). First, I describe two cases of envenomation at separate Arizona localities (Tinajas Altas Mountains, Yuma County, and Phoenix Mountains, Maricopa County). Both patients experienced swelling, but neither demonstrated coagulopathy, thrombocytopenia, or hypofibrinogenemia. The latter patient required amputation of the distal portion of his middle finger. I also investigated variation in morphology, diet, and …

Determining Heavy Metal Concentrations In The Blueband Hermit Crab (Pagurus Samuelis), Tyler Dos Santos

Loma Linda University Electronic Theses, Dissertations & Projects

Although heavy metal concentrations fluctuate naturally in the environment, anthropogenic sources of heavy metal concentrations can mask and override natural fluctuations. Large anthropogenic metal concentrations can lead to deleterious effects in organisms, such as malformation or death. Indicator species can be used to determine environmental concentrations of certain metals to help understand the impacts of anthropogenic sources of heavy metal concentrations. The aim of this study was to determine if Pagurus samuelis may play a role as an indicator species by analyzing specimens for Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb), and Zinc (Zn) found in tidepool seawater in …

Size, Shape, And Sexual Dimorphism Of Island And Mainland Melanerpes Woodpeckers Of The Centurus Clade, Lee Michelle Silva Núñez

Loma Linda University Electronic Theses, Dissertations & Projects

Island ecosystems are widely studied as "natural laboratories” for biological change. Animals that colonize islands frequently exhibit differences from their mainland counterparts in morphology, physiology, and behavior. Some of the most striking features include changes in body size and shape, with extreme examples being dwarfism, gigantism, and flightlessness. These changes are generally driven by isolation and reduction in predators and competitors. The 10 woodpecker species belonging to the Centurus clade of genus Melanerpes are ideally suited to study evolutionary changes associated with island conditions because they include numerous populations restricted to islands, allowing comparisons among island and continent ecosystems. To …

Signaling Pathways In Skeletal Development And Metabolism, Richard Charles Lindsey

Loma Linda University Electronic Theses, Dissertations & Projects

Osteoporosis, a disease characterized by low bone mass and microarchitectural deterioration, causes nine million debilitating fractures annually. An increase in bone resorption not adequately compensated by a corresponding increase in bone formation is the major cause of osteoporosis. Since current therapies have failed to effectively eliminate osteoporosis, there is an urgent need to discover novel mechanisms regulating bone resorption and formation and develop new therapeutic approaches to treat this disease. To that end, we have explored novel, non-canonical signaling mechanisms of two well-established regulators of bone: thyroid hormone (TH) and vitamin C (ascorbic acid, AA). Since previous studies have shown …

A Novel Exo-Proteomic Approach To The Study Of Traumatic Brain Injury, Ron B. Moyron

Loma Linda University Electronic Theses, Dissertations & Projects

Concussions and Traumatic Brain Injuries (TBI) are significant health concerns and affect a wide cross section of society. Current diagnostic criteria and modalities, such as brain imaging and subjective measures of consciousness such as the Glasgow Coma Scale (GCS) score, are insufficient to properly diagnose the full spectrum of head injuries. Assessment of injury severity and outcome are further complicated by the vast array of symptoms, many of which mimic those displayed by other disorders. It is important to possess a better diagnostic tool for head injury triage and outcome prediction. One current line of inquiry seeks to discover a …

Characterization Of Fgf-Mediated Sonic Hedgehog Expression During Limb Development, Billy A. Watson

Loma Linda University Electronic Theses, Dissertations & Projects

Crosstalk between Fibroblast Growth Factors (FGFs) and Sonic hedgehog (SHH) is essential for proper limb development; however, the molecular mechanisms involved in this process remain unclear. Via comparative transcriptome analysis and gene knockdown and overexpression studies, we identified the transcription factor Lim homeobox 2 (LHX2) as an intermediate in FGF-directed SHH expression. We determined that FGF signaling was necessary for LHX2 expression and demonstrated that LHX2 is a primary transcription target of FGF signaling through the RAS and AKT pathways. Additionally, loss of LHX2 in the distal limb results in decreased SHH expression and a truncated limb within 24 hours …

Rna-Seq Reveals Transcriptomic Program Associated With Stemness In Taxane Resistant Prostate Cancer, Christina K. Cajigas-Du Ross

Loma Linda University Electronic Theses, Dissertations & Projects

There is no cure for advanced prostate cancer (PCa), and taxane chemotherapy is the only treatment option once other therapies have failed. However, this is problematic since all patients eventually develop chemoresistance. Emerging treatments for advanced PCa have shown promise at the benchside, but clinical trials have not resulted in newly approved drugs due in part to redundant survival pathways utilized by prostate tumor cells to maintain therapy-resistance. Using RNAsequencing—an innovative approach for quantifying gene expression changes—this dissertation sought to elucidate chemoresistance-associated molecular pathways as a catalyst to develop new therapeutic targets. Results revealed a differential upregulation of stemness-associated genes …

Aryl Hydrocarbon Receptor Mediated Restoration Of Cytoglobin As A Treatment For Breast Cancer, Leah Kathleen Rowland

Loma Linda University Electronic Theses, Dissertations & Projects

Nearly 40,000 women die annually from breast cancer in the US. Clinically available targeted breast cancer therapy is ineffective in triple negative breast cancer (TNBC) subtypes, which lack expression of the estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2. TNBC carries a poor prognosis. Previous reports show that aryl hydrocarbon receptor (AhR) agonist 2-(4-amino-3-methylphenyl)- 5-fluorobenzothiazole (5F 203) selectively inhibits the growth of breast cancer cells including those of the TNBC subtype. In the current study, we determined that 5F 203 induces the expression of epigenetically silenced putative tumor suppressor gene cytoglobin (CYGB) and suppresses TNBC cell growth …

The Design Of Complex Weapons Systems In Scorpions: Sexual, Ontogenetic, And Interspecific Variation, Gerard A. A. Fox

Loma Linda University Electronic Theses, Dissertations & Projects

Scorpions possess two integrated multifunctional weapons systems. Anteriorly, they maintain a grasping system comprised of a pair of pedipalps ending in chelae that seize and manipulate prey, ward off predators, and secure mates. Posteriorly, they wield a venom delivery system consisting of a tail-like metasoma with a stinger at the tip of the terminal segment (telson) that can be thrust into prey, predators, or mates to inject venom. Given the complexity of these systems, I hypothesized that weaponry design is subject to selective forces arising from differences in usage between the sexes, during ontogeny, and among closely-related species occupying different …

Pain And Stress In The Premature Infant, John Bryle Chong Tan

Loma Linda University Electronic Theses, Dissertations & Projects

Procedural pain and stress in premature neonates is currently assessed utilizing tools that lack objectivity and accuracy. This results in untreated or mismanaged pain. My dissertation utilized physiological methods and biochemical markers that identified pain in premature neonates and its effect on energy metabolism. The painful procedure that I examined is the retinopathy of premature (ROP) examination, a necessary and routine eye examination in the neonatal intensive care unit (NICU) that detects and identifies infants at risk for blindness due to retinal detachment. The effects of the ROP exam on peripheral and deep tissue oxyhemoglobin saturation and urinary purine degradation …

Effects Of Omega-3s And Vitamin E Prophylactic Diets And The Implications Of Lipid Transport In Spinal Cord Injury, Kathia Cordero-Caban

Loma Linda University Electronic Theses, Dissertations & Projects

Traumatic injury to the central nervous system (CNS) presents a devastating problem to our society. Although current interventions are promising, no effective treatments are available. The neural membrane fatty acid composition is markedly altered during the first few days after spinal cord injury (SCI). SCI results in autonomic dysfunction, paralysis, spasticity, and significant chronic neuropathic pain. The trauma leads to significantly increased levels of free radical and oxidative stress that contribute to obstructing tissue healing and recovery. A growing body of evidence shows that administration of hydrophobic molecules such as Vitamin E and long-chain omega-3 polyunsaturated fatty acids (ω3PUFAs) are …

The Effects Of Daily Ginger Tea Consumption In Reducing Period Discomfort, Kristy Valencia, Sherllie Kartika

Loma Linda University Research Reports

Background

Ginger has been known for its medicinal purposes which includes treating inflammation.⁶ Researchers have observed the effects of ginger capsules to alleviate dysmenorrhea, but few studies have investigated the use of ginger tea.^6,7,9,10,11 The effects of ginger tea on adolescent females have been studied and researchers concluded that ginger reduces menstrual discomfort.^1,2

Objective

The purpose of our study was to observe the effects of daily ginger tea consumption on menstrual discomfort in non-adolescent menstruating women.

Design

Our study was a quantitative, interventional study.

Participants/setting

Subjects were females aged 18 years and above. Participants were mostly students …

A Comparative Microbial Composition Assessment Of Stormwater, Urban Runoff And Wastewater, Rose Syomiti Mutiso

Loma Linda University Electronic Theses, Dissertations & Projects

The goal of this study was to compare two methods for assessment of fecal indicator bacteria (FIB) in urban runoff (n = 96), stormwater (n = 8), and wastewater (n = 16). We quantified the densities and reductions of E. coli and Enterococcus, in raw stormwater, treated urban off from the Santa Monica Urban Runoff Recycling Facility (SMURRF) and wastewater from the Eastern Municipal Water District’s (EMWD) Moreno Valley water reclamation facility. We compared the overall FIB recovery efficiency by two varieties of USEPA-approved, culture-based laboratory methods in each type of water. The two types of methods were the IDEXX …

Behavioral Ecology And Associated Virology Of Mosquito-Host Interactions In Southern California, Oliver Eshun

Loma Linda University Electronic Theses, Dissertations & Projects

Elucidating characteristics of mosquito-host interactions are critical for understanding the ecology and epidemiology of mosquito-borne diseases. In this dissertation, I conducted three studies to explore potential mosquito-host interactions and associated virus infection rates. I first demonstrated that mosquito captures at CO2-baited traps decreased most markedly with height above ground, and also decreased with distance from water at a riparian area but not at an open water source lacking a vegetated border. Birds might therefore prefer elevated nests or roosts to avoid mosquitoes. The second study examined the anti-mosquito behaviors of budgerigars (Melopsittacus undulatus) in a laboratory study. The birds defended …

Effect Of Extracellular Survivin And Lymphoma Exosomes On Natural Killer Cells, Heather R. Ferguson Bennit

Loma Linda University Electronic Theses, Dissertations & Projects

Tumors alter their microenvironment to promote survival using methods such as angiogenesis promotion, growth signals, and immune suppression. The immune system becomes unresponsive to transformed neoplastic cells through a variety of methods including T cell suppression, increased myeloid-derived suppressor cells (MDSCs), and reduced natural killer (NK) cell activity. NK cells have inherent killing capabilities and thus are among the first responders in recognizing and destroying abnormal cells. However, many types of cancers inhibit the surveillance and cytotoxic abilities of NK cells by releasing exosomes, vesicles that can modulate the tumor microenvironment (TME) and intercellular communication for the purpose of enhancing …

Prenatal Undernutrition, Metyrapone, And The Cerebrovasculature, Lara Durrant

Loma Linda University Electronic Theses, Dissertations & Projects

The link between intrauterine environmental conditions and adult cardiovascular system is well established. Independent of lifestyle factors such as poor diet and exercise habits, individuals who have been exposed to stressful conditions in utero show an increased risk of health problems such as hypertension, stroke, and type II diabetes. In support of the Fetal Origin of Adult Disease hypothesis, many labs have reported permanent anatomical and physiological changes associated with fetal stress and nutrient deficiency, with a focus on organ systems such as the kidney and heart. One key idea proposed by many of these studies is the glucocorticoid hypothesis, …