Molecular Biology Commons^™

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 …

Identifying The Cell Composition And Clonal Diversity Of Supratentorial Ependymoma Using Single Cell Rna-Sequencing, James He

Honors Scholar Theses

Ependymoma is a primary solid tumor of the central nervous system. Supratentorial ependymoma (ST-EPN), a subtype of ependymomas, is driven by an oncogenic fusion between the ZFTA and RELA genes in 70% of cases. We introduced this fusion into neural progenitor cells of mice embryos via in utero electroporation of a non-viral binary piggyBac transposon system containing ZFTA-RELA. From preliminary data in the LoTurco lab, inducing the expression of ZFTA-RELA into different neural progenitor cells produces tumors of varying lethality and cellular composition. To define the cellular composition and subclonal diversity of ST-EPN tumors, we used single cell RNA-sequencing …

The Role Of Nutrition And Hormone Signaling In Extended Larval Development And Obesity In Starvation-Selected Drosophila Melanogaster, Jennifer M. Clark

UNLV Theses, Dissertations, Professional Papers, and Capstones

Brief periods of starvation are a common stressor that most animals encounter in the wild and must be able to survive in order to maximize their fitness. Starvation resistance of the adult fruit fly, Drosophila melanogaster, is thought to be primarily conferred by adult fat stores, body size, metabolic rate, behavior, and activity levels. Additionally, flies selected for starvation resistance also often show delayed pupariation, which is usually indicative of altered hormone signaling. How starvation selection extends development and if it contributes to adult starvation resistance remains incompletely studied. Identifying the targets of starvation selection that cause extended development and …

Lighting The Way: Recent Insights Into The Structure And Regulation Of Phototropin Blue Light Receptors, Jaynee E. Hart, Kevin H. Gardner

Publications and Research

The phototropins (phots) are light-activated kinases that are critical for plant physiology and the many diverse optogenetic tools that they have inspired. Phototropins combine two bluelight- sensing Light–Oxygen–Voltage (LOV) domains (LOV1 and LOV2) and a C-terminal serine/threonine kinase domain, using the LOV domains to control the catalytic activity of the kinase. While much is known about the structure and photochemistry of the light-perceiving LOV domains, particularly in how activation of the LOV2 domain triggers the unfolding of alpha helices that communicate the light signal to the kinase domain, many questions about phot structure and mechanism remain. Recent studies have made …

Characterization Of The Whale Shark (Rhincodon Typus) Melanocortin-2 Receptor, Brianne Hoglin

Electronic Theses and Dissertations

Among bony vertebrates, the melanocortin-2 receptor ortholog is unique among the family of five melanocortin receptors on the basis that it is dependent on its accessory protein, MRAP1, for trafficking and activation, and is selective for activation by ACTH alone. Previous studies on the MC2R orthologs of select cartilaginous fish, the elephant shark (Callorhinchus milii) and the red stingray (Dasyatis akajei), revealed divergent traits in a less obligatory relationship on MRAP1 and its ability to be activated by ACTH or the MSH-sized peptides. However, observed traits were not consistent between these two cartilaginous fish species, posing …

A Novel Review Of Heat Shock Protein 110 Kda: A Basis For Research And Continued Experimentation Through Biochemical Analysis, Crist W. Cuffee

Theses and Dissertations

Heat shock protein 110 kDa, Hsp110, is a distinct cellular protector, different in form and function from Hsp70, a close relative of Hsp110. Functioning primarily as a holdase or in tandem with other molecular chaperones, a review of current accomplishments elucidates the uniqueness of this protein and the continued mysteries that surrounds it. Found only in eukaryotes, Hsp110 has been linked to many diseases, ranging from parasitic infection to neurodegenerative disorders. While still lacking, studies of this protein have provided much in the realm of speculation on the mechanisms behind Hsp110s’ contribution to different pathologies. This review will serve as …

The Tumor Suppressor Par-4 Regulates Hypertrophic Obesity, Nathalia Araujo

Theses and Dissertations--Toxicology and Cancer Biology

Prostate Apoptosis Response-4 (Par-4) is a tumor suppressor ubiquitously expressed in all tissues and able to selectively induce apoptosis in cancer cells. Although well established in the context of cancer, relatively little is known about the function of Par-4 in the healthy and non-tumorigenic context. Observations from our lab showed that Par-4 knockout mouse lines were obese and displayed adipocyte hypertrophy under a normal chow diet when compared to Par-4 wild-type mice. These Par-4 knockout mice exhibited hepatic steatosis and hyperinsulinemia as secondary consequences of obesity. Par-4 knockout mice displayed increased intestinal dietary fat absorption and its subsequent storage in …

The Effect Of Epa And Dha On Skeletal Muscle Physiology And Energy Balance, Saeed Jebor Ghnaimawi

Graduate Theses and Dissertations

Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) supplementation commonly suggested during pregnancy confers many health benefits on offspring and more recently improves fetal BAT development and induces myoblast trans-differentiation into adiopocytes through activating PPARs expression. Embryonic myoblast is a highly flexible cell showing great capacity to change its phenotype into adipocyte in response to EPA and DHA supplementation in many in vitro models. However, a little is known about the identity of derived adipocytes, whether, they change into brown or white adipocyte, and in vivo evidence is still missing. Given that the myogeneis process is initiated at the mid of …

Modulation Of Escherichia Coli Translation By The Specific Inactivation Of TrnaGly Under Oxidative Stress, Lorenzo Eugenio Leiva, Andrea Pincheira, Sara Elgamal, Sandra D. Kienast, Verónica Bravo, Johannes Leufken, Daniela Gutiérrez, Sebastian A. Leidel, Michael Ibba, Assaf Katz

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Bacterial oxidative stress responses are generally controlled by transcription factors that modulate the synthesis of RNAs with the aid of some sRNAs that control the stability, and in some cases the translation, of specific mRNAs. Here, we report that oxidative stress additionally leads to inactivation of tRNA^Gly in Escherichia coli, inducing a series of physiological changes. The observed inactivation of tRNA^Gly correlated with altered efficiency of translation of Gly codons, suggesting a possible mechanism of translational control of gene expression under oxidative stress. Changes in translation also depended on the availability of glycine, revealing a mechanism whereby bacteria …

Translational Regulation Of Environmental Adaptation In Bacteria, Rodney Tollerson Ii, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Bacteria must rapidly respond to both intracellular and environmental changes to survive. One critical mechanism to rapidly detect and adapt to changes in environmental conditions is control of gene expression at the level of protein synthesis. At each of the three major steps of translation—initiation, elongation, and termination—cells use stimuli to tune translation rate and cellular protein concentrations. For example, changes in nutrient concentrations in the cell can lead to translational responses involving mechanisms such as dynamic folding of riboswitches during translation initiation or the synthesis of alarmones, which drastically alter cell physiology. Moreover, the cell can fine-tune the levels …

The Impact Of Age/Rage Signaling On Oxidative Stress Under Diabetic Conditions In Cardiac Fibroblasts, Christopher Dorroh

Honors Theses

Diabetes is a major health concern in the United States, with 1.5 million new cases diagnosed each year. Patients who suffer from diabetes have an increased risk of developing heart failure, a form of cardiovascular disease. Heart failure has been shown to result from increased left ventricular stiffness, which in turn is caused by increased remodeling of the extracellular matrix (ECM). This increase in ECM remodeling is a result of AGE/RAGE signaling, which occurs at a heightened level in the cardiac fibroblast cells of diabetics. Studies have shown that diabetics have elevated levels of AGEs (Advanced Glycation End-Products), which bind …

The Autoimmune System: The Effect Of Physiological Stressors On Autoantibody Glycosylation And Fidelity Of Autoantibody Profiles, Rahil Kheirkhah

Graduate School of Biomedical Sciences Theses and Dissertations

The presence of thousands of autoantibodies (aABs) in the human sera is typical, and therefore it is possible to identify an aAB profile for each individual. In the first part of this thesis, we will show the cerebrospinal fluid also exhibits an extraordinarily complex immunoglobulin G aAB profile that is composed of thousands of aABs. We show that the pattern of expression of individual aABs in CSF closely mimics that in the blood, indicative of a blood-based origin for CSF aABs. In addition, using longitudinal serum samples obtained over a span of nine years, we show remarkable stability in aAB …

Alternative Polyadenylation Modulates Expression Of Pro-Fibrotic Proteins And Contributes To Lung Fibrosis, Junsuk Ko

Dissertations and Theses (Open Access)

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease which affects about 5 to 8 million individuals in the world. Despite the high prevalence, there is currently no cure for IPF, and the cause of this disease is still unclear. Our laboratory and collaborators have shown that nudix hydrolase 21 (NUDT21, which is also known as cleavage factor 25, CFIm25) is a key regulator of alternative polyadenylation (APA). NUDT21 depletion causes 3’UTR shortening via APA leading to enhanced mRNA stability and protein translation. This NUDT21 reduction promotes tumor growth in glioblastoma by enhancing expression of oncogenes. Cancer and IPF share …

Rapid Evolution Of Starvation Resistance In Drosophila: Physiological And Molecular Mechanisms, Austin Joseph Mckenna

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Gibbs lab has maintained starvation-selected Drosophila melanogaster for >130 generations. These starvation-selected flies evolved an obese phenotype with a suite of physiological differences compared to control-fed flies. Previous studies have shown that long-term starvation-selected Drosophila contain more lipids, have lower metabolic rates and develop more slowly than controls. This dissertation encompasses 1) Examining the molecular mechanisms contributing to starvation resistance, 2) Functional validation of the candidate plin1 allele, and 3) Rapid physiological and genomic evolution in starvation-selected Drosophila.

Starvation-selected Drosophila survive starvation conditions much longer than control-fed flies. This study took a simple approach to identify possible differences in …

Aminoacyl-Trna Synthetases, Miguel Angel Rubio Gomez, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The aminoacyl-tRNA synthetases are an essential and universally distributed family of enzymes that plays a critical role in protein synthesis, pairing tRNAs with their cognate amino acids for decoding mRNAs according to the genetic code. Synthetases help to ensure accurate translation of the genetic code by using both highly accurate cognate substrate recognition and stringent proofreading of noncognate products. While alterations in the quality control mechanisms of synthetases are generally detrimental to cellular viability, recent studies suggest that in some instances such changes facilitate adaption to stress conditions. Beyond their central role in translation, synthetases are also emerging as key …

Mixed-Lineage Kinase-3 (Mlk3) Plays A Negative Modulatory Role In Insulin Secretion From The Pancreatic Β-Cell, Tyler Russeth, Vijayalakshmi Thamilselvan, Anjaneyulu Kowluru

Medical Student Research Symposium

Glucose-stimulated insulin secretion (GSIS) from the pancreatic β-cell in response to elevated levels of glucose is controlled by a variety of signals including intracellular calcium and nucleotides such as cAMP, ATP and GTP. These cellular signals are responsible for activation of specific kinases that mediate phosphorylation of key exocytotic proteins that lead to GSIS. In the context of protein kinases, mixed-lineage kinases (MLKs) have been implicated in an assortment of cellular functions, including cell proliferation and apoptosis. However, very little is known on potential regulatory roles of MLKs in islet β-cell function, including GSIS. The goal of this study is …

Targeting Trna-Synthetase Interactions Towards Novel Therapeutic Discovery Against Eukaryotic Pathogens, Paul Kelly, Fatemeh Hadi-Nezhad, Dennis Y. Liu, Travis J. Lawrence, Roger G. Linington, Michael Ibba, David H. Ardell

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The development of chemotherapies against eukaryotic pathogens is especially challenging because of both the evolutionary conservation of drug targets between host and parasite, and the evolution of strain-dependent drug resistance. There is a strong need for new nontoxic drugs with broad-spectrum activity against trypanosome parasites such as Leishmania and Trypanosoma. A relatively untested approach is to target macromolecular interactions in parasites rather than small molecular interactions, under the hypothesis that the features specifying macromolecular interactions diverge more rapidly through coevolution. We computed tRNA Class-Informative Features in humans and independently in eight distinct clades of trypanosomes, identifying parasite-specific informative features, …

Non-Invasive Method For Leptin Supplementation In Zebrafish (Danio Rerio), Regan Mcnamara

Williams Honors College, Honors Research Projects

I tested the hypothesis that recombinant leptin protein can be introduced to zebrafish in vivo through non-invasive soaking in a solution containing the protein. One way to study various molecules’ effects in vivo is through intraperitoneal or intracerebroventricular injections during the embryonic or larval stage, which is invasive, difficult to administer, and can have a high mortality rate. 48 hours post fertilization (hpf) zebrafish were soaked in a His-tagged recombinant leptin protein solution at 10 nM and 100 nM concentrations (produced by Genscript). After soaking, zebrafish larvae were washed extensively to remove all recombinant protein on their exterior before homogenization. …

Alanyl-Trna Synthetase Quality Control Prevents Global Dysregulation Of The Escherichia Coli Proteome, Paul Kelly, Nicholas Backes, Kyle Mohler, Christopher Buser, Arundhati Kavoor, Jesse Rinehart, Gregory Phillips, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Mechanisms have evolved to prevent errors in replication, transcription, and translation of genetic material, with translational errors occurring most frequently. Errors in protein synthesis can occur at two steps, during tRNA aminoacylation and ribosome decoding. Recent advances in protein mass spectrometry have indicated that previous reports of translational errors have potentially underestimated the frequency of these events, but also that the majority of translational errors occur during ribosomal decoding, suggesting that aminoacylation errors are evolutionarily less tolerated. Despite that interpretation, there is evidence that some aminoacylation errors may be regulated, and thus provide a benefit to the cell, while others …

The Fitness Landscape Of The African Salmonella Typhimurium St313 Strain D23580 Reveals Unique Properties Of The Pbt1 Plasmid, Rocío Canals, Roy R. Chaudhuri, Rebecca E. Steiner, Siân V. Owen, Natalia Quinones-Olvera, Melita A. Gordon, Michael Baym, Michael Ibba, Jay C. D. Hinton

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We have used a transposon insertion sequencing (TIS) approach to establish the fitness landscape of the African Salmonella enterica serovar Typhimurium ST313 strain D23580, to complement our previous comparative genomic and functional transcriptomic studies. We used a genome-wide transposon library with insertions every 10 nucleotides to identify genes required for survival and growth in vitro and during infection of murine macrophages. The analysis revealed genomic regions important for fitness under two in vitro growth conditions. Overall, 724 coding genes were required for optimal growth in LB medium, and 851 coding genes were required for growth in SPI-2-inducing minimal medium. These …

Inhibition Of Mitochondrial Permeability Transition By Deletion Of The Ant Family And Cypd, Jason Karch, Michael J. Bround, Hadi Khalil, Michelle A. Sargent, Nadina Latchman, Naohiro Terada, Pablo M. Peixoto, Jeffery D. Molkentin

Publications and Research

The mitochondrial permeability transition pore (MPTP) has resisted molecular identification. The original model of the MPTP that proposed the adenine nucleotide translocator (ANT) as the inner membrane pore-forming component was challenged when mitochondria from Ant1/2 double null mouse liver still had MPTP activity. Because mice express three Ant genes, we reinvestigated whether the ANTs comprise the MPTP. Liver mitochondria from Ant1, Ant2, and Ant4 deficient mice were highly refractory to Ca2+-induced MPTP formation, and when also given cyclosporine A (CsA), the MPTP was completely inhibited. Moreover, liver mitochondria from mice with quadruple deletion of Ant1, Ant2, Ant4, and Ppif (cyclophilin …

Translational Control Of Antibiotic Resistance, Anne Witzky, Rodney Tollerson Ii, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Many antibiotics available in the clinic today directly inhibit bacterial translation. Despite the past success of such drugs, their efficacy is diminishing with the spread of antibiotic resistance. Through the use of ribosomal modifications, ribosomal protection proteins, translation elongation factors and mistranslation, many pathogens are able to establish resistance to common therapeutics. However, current efforts in drug discovery are focused on overcoming these obstacles through the modification or discovery of new treatment options. Here, we provide an overview for common mechanisms of resistance to translation-targeting drugs and summarize several important breakthroughs in recent drug development.

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi S. Patel

University Scholar Projects

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi Patel

Honors Scholar Theses

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

A Dedicated Chaperone Mediates The Safe Transfer Of Mitoribosomal Proteins To Their Site Of Assembly, Gabrielle Ashley Hillman

Graduate School of Biomedical Sciences Theses and Dissertations

Mitochondrial ribosomes are functionally specialized for the synthesis of several essential inner membrane proteins of the respiratory chain. While remarkable progress has recently been made towards understanding the structure of mitoribosomes, the unique pathways and factors that facilitate their biogenesis remain largely unknown. This dissertation defines the physiological role of an evolutionarily conserved yeast protein called Mam33 in mitochondrial ribosome assembly. The biomedical relevance of this finding stems from the fact that mutations or changes in its expression of the human ortholog p32 result in mitochondrial dysfunction. In human patients, bi-allelic mutations cause severe multisystemic defects in mitochondrial energy metabolism, …

Extracellular Vesicles As Biological Shuttles For Targeted Therapies., Stefania Raimondo, Gianluca Giavaresi, Aurelio Lorico, Riccardo Alessandro

College of Osteopathic Medicine (TUN) Publications and Research

The development of effective nanosystems for drug delivery represents a key challenge for the improvement of most current anticancer therapies. Recent progress in the understanding of structure and function of extracellular vesicles (EVs)-specialized membrane-bound nanocarriers for intercellular communication-suggests that they might also serve as optimal delivery systems of therapeutics. In addition to carrying proteins, lipids, DNA and different forms of RNAs, EVs can be engineered to deliver specific bioactive molecules to target cells. Exploitation of their molecular composition and physical properties, together with improvement in bio-techniques to modify their content are critical issues to target them to specific cells/tissues/organs. Here, …

The Relationship Between Seasonal Breeding And Deiodinase Expression In The Green Anole Lizard, Hyejoo Kang

All Graduate Theses, Dissertations, and Other Capstone Projects

Reproductive physiology and behavior is mainly regulated by the hypothalamus-pituitary-gonad (HPG) axis. Interestingly, abnormal levels of thyroid hormone (TH) results in the delayed onset of puberty and affects gonadal function of adults by altering HPG axis activity. Seasonally breeding animals undergo drastic hormonal and behavioral changes between breeding and non-breeding seasons. Green anole lizards (Anolis carolinensis), similar to other seasonally breeding animals, have increased sex steroid hormones, larger gonads, upregulated gonadal steroidogenic acute regulatory protein (StAR) mRNA and increased reproductive behavior during the breeding compared to non-breeding seasons. Relatively less is known regarding the regulation of gonadal TH in seasonal …

The Balance Between Prostaglandin E2 Ep3 And Ep4 Receptors Determines Severity Of Cardiac Damage In Myocardial Infarction And An Angiotensin Ii-Induced Model Of Hypertension, Timothy Dean Bryson

Wayne State University Dissertations

According to the center for disease control about 610,000 people die every year in the United States from heart disease, of which, coronary heart disease is the most common form. One major risk factor for heart attack is hypertension, which affects nearly half of all Americans [472, 473]. PGE2 plays an important role in regulating cardiovascular function and mediating inflammation, both of which contribute to the development of hypertension and/or heart disease. Prostaglandin E2 can act as a vasodilator or vasoconstrictor depending on which of its receptor subtypes are activated.

In general, activation of the EP1 and EP3 receptors is …

Development Of A Biomarker Panel For Identifying Stressed Marine Mammals, Laura Pujade

University of the Pacific Theses and Dissertations

Increasing anthropogenic disturbance in marine ecosystems such as fishing, oil-drilling, and noise pollution can have detrimental effects on the reproduction and survival of apex predators such as marine mammals. Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, resulting in increased circulating glucocorticoid (GCs) hormones, which alter expression of target genes encoding metabolic enzymes and other mediators of stress. Prolonged HPA axis stimulation may increase catabolism of nutrient stores and suppress immune and reproductive functions, impacting the fitness of marine mammals. GCs measurements are used to identify wild animals experiencing stress. However, these measurements may not be sensitive enough to distinguish between an …

Effects Of Aquatic Acidification On Calcium Uptake In White River Shrimp Litopenaeus Setiferus Gills, Maria-Flora Jacobs

UNF Graduate Theses and Dissertations

Previous research regarding aquatic acidification has examined the protonation of the carbonate and does not consider calcium to be a limiting factor. This is the first study to suggest that pH may affect the uptake of calcium in crustacean gills. This project describes ion transport mechanisms present in the cell membranes of white river shrimp Litopenaeus setiferus gill epithelium, and the effects of pH on the uptake of calcium by these means. Partially purified membrane vesicles (PPMV) of shrimp gills were prepared through a homogenization process that has been used previously to define ion transport in crab and lobster gill …