Open Access. Powered by Scholars. Published by Universities.®

Cell and Developmental Biology Commons™

Open Access. Powered by Scholars. Published by Universities.®

Portland State University

Discipline
Keyword
Publication Year
Publication
Publication Type

Articles 1 - 30 of 59

Full-Text Articles in Cell and Developmental Biology

Stayin' Alive (Even Without Oxygen): Retinal Development In Austrofundulus Limnaeus, Carmen Zecilia Rodriguez Sep 2025

Stayin' Alive (Even Without Oxygen): Retinal Development In Austrofundulus Limnaeus, Carmen Zecilia Rodriguez

Dissertations and Theses

The vertebrate eye is one of the most metabolically active organs in the body and is particularly sensitive to environmental stressors such as oxygen deprivation. Understanding how eye development proceeds under such conditions can provide critical insights into mechanisms of cellular resilience, tissue organization, and developmental plasticity. The annual killifish Austrofundulus limnaeus represents a unique model for investigating these processes due to its remarkable tolerance to anoxia during embryogenesis. However, the wild-type form is heavily pigmented, limiting the effectiveness of traditional imaging techniques for studying eye development. This thesis characterizes eye development and anoxia resilience in both wild-type and melanin-deficient …

Go to article

Is Anoxia Tolerance A Common Trait In Fish Cell Lines?, Lori Tran Jun 2025

Is Anoxia Tolerance A Common Trait In Fish Cell Lines?, Lori Tran

University Honors Theses

Most vertebrates need a constant supply of oxygen to sustain life, with disruption to O2 supply or delivery quickly leading to cell and tissue damage and death. Many aquatic species are able to withstand long periods without O2 due to evolving to survive the regular periods of hypoxia and anoxia in their natural habitat. The Austrofundulus limnaeus, or the annual killifish, in particular have shown the highest anoxia tolerance in all vertebrates and is a promising model for developing effective treatments for anoxia-related damage, such as heart attacks and strokes. The A. limnaeus are not the only …

Go to article

Breaking The Rules: Post-Translational Modifications And Proteome Dynamics During Anoxia, Chelsea Jordan Hughes Jun 2025

Breaking The Rules: Post-Translational Modifications And Proteome Dynamics During Anoxia, Chelsea Jordan Hughes

Dissertations and Theses

Most organisms are ill-equipped to survive anoxia, but some organisms have developed molecular strategies to mitigate the cellular stressors associated with a lack of oxygen. While it is established that anoxic survival is contingent on metabolic suppression, it is unclear what mechanisms support this change in gene expression. Gene expression is regulated by a variety of mechanisms within the cell, including alteration of chromatin structure through histone modifications and protein modifications which contribute to the ever-changing proteomic landscape of the cell. Protein modifications such as ubiquitylation can lead to the degradation of proteins, while modifications to transcription factors can change …

Go to article

Investigating A Link Between Dna Repair And Dna Replication In Escherichia Coli Using A Bacterial Two-Hybrid System, Lo Cooper Jun 2025

Investigating A Link Between Dna Repair And Dna Replication In Escherichia Coli Using A Bacterial Two-Hybrid System, Lo Cooper

University Honors Theses

Cells rely on nucleotide excision repair (NER) to remove bulky DNA lesions, such as those caused by UV light. In Escherichia coli, NER involves the UvrABC complex, and includes two main pathways, global genomic repair and transcription-coupled repair (TCR). While TCR, which preferentially removes lesions that block RNA polymerase on the transcribed strand of active genes, is well studied, less is known about whether a similar coupling between repair proteins and replisomes blocked by damaged DNA exists. Such a process has been suggested by a high throughput interactome study, using the replisome subunit HolC as bait and the damage …

Go to article

Examining The Role Of Rgs2 In The Maintenance Of Diapause After Anoxic Stress In Embryos Of The Annual Killifish Austrofundulus Limnaeus, Patrick Clouser May 2024

Examining The Role Of Rgs2 In The Maintenance Of Diapause After Anoxic Stress In Embryos Of The Annual Killifish Austrofundulus Limnaeus, Patrick Clouser

Student Research Symposium

Austrofundulus limnaeus live in ephemeral ponds of Venezuela. They have evolved a unique life history that includes embryonic diapause, a period of developmental dormancy, metabolic arrest, and reduced protein synthesis. Diapausing embryos are resistant to environmental stress and survive months without oxygen (anoxia). A. limnaeus’ anoxia tolerance is an important survival mechanism as they can be buried in anoxic soil during development. Analysis of RNAseq data from diapausing A. limnaeus embryos show significant down-regulation of RGS2 transcripts in anoxic embryos. RGS2 regulates G-protein receptor signaling by inhibiting associated Ga-proteins and can inhibit protein synthesis. I hypothesis that …

Go to article

Locating Vitamin D Receptors (Vdrs) In Annual Killifish, Austrofundulus Limnaeus, Rosalia N. Tanori, Amie L. Romney, Jason E. Podrabsky May 2024

Locating Vitamin D Receptors (Vdrs) In Annual Killifish, Austrofundulus Limnaeus, Rosalia N. Tanori, Amie L. Romney, Jason E. Podrabsky

Student Research Symposium

Austrofundulus limnaeus, a species of annual killifish found in unpredictable temporary habitats in South America, has a profound ability to survive long periods without water and oxygen. This tolerance is associated with the ability to enter metabolic dormancy associated with diapause. Entrance into diapause and tolerance of environmental stress is governed by an interplay of genetic and environmental factors. The vitamin D receptor (VDR) is among these factors and plays a crucial role in determining if an embryo will enter diapause or actively develop. My work aims to identify the genomic locations of VDR proteins in the A. limnaeus genome …

Go to article

Annual Killifish: Eye Development And Retinal Cell Regeneration, Carmen Z. Rodriguez May 2024

Annual Killifish: Eye Development And Retinal Cell Regeneration, Carmen Z. Rodriguez

Student Research Symposium

Vertebrate eye development is highly conserved. Current models have allowed the understanding of gene expression patterns that support eye development, but lack the context of extreme environmental conditions that challenge these fundamental programs. Typical vertebrate life spans can be years, but annual killifish, Austrofundulus limnaeus, are able to complete their entire adult lifespan in only weeks. Thus, A. limnaeus is a strong model for age-related macular degeneration. A. limnaeus also experiences embryonic diapause; a period of developmental dormancy. Developing/diapausing embryos of A. limnaeus are resistant to environmental stresses such as hypoxia/anoxia that would cause irreparable damage to vital organs, such …

Go to article

Mechanisms Of Substrate Recognition By The Cul3-Based E3 Ligase, Katia Graziella De Oliveira Rebola Sep 2021

Mechanisms Of Substrate Recognition By The Cul3-Based E3 Ligase, Katia Graziella De Oliveira Rebola

Dissertations and Theses

Cul3-based E3 ligase is responsible for regulating a variety of cellular pathways, many of which are known to have profound effects on the proper function of multicellular organisms. Although progress over the past years has been truly impressive, our understanding of the mechanisms of E2 recruitment and selection by the BCR complex and all the roles that Cul3 plays on kidneys remains in its infancy. To explore these aspects, this dissertation aims to analyze the Cul3 complex using two different approaches: (1) We used the powerful tool of chimeric analysis to map the essential domain binding characteristics of Cul3 taking …

Go to article

Trem2 Is Thyroid Hormone Regulated Making The Trem2 Pathway Druggable With Ligands For Thyroid Hormone Receptor., Skylar J. Ferrara, Priya Chaudhary, Margaret J. Debell, Gail Marracci, Hannah Miller, Evan Calkins, Edvinas Pocius, Brooke A. Napier, Ben Emery, Dennis Bourdette, Thomas S. Scanlan Aug 2021

Trem2 Is Thyroid Hormone Regulated Making The Trem2 Pathway Druggable With Ligands For Thyroid Hormone Receptor., Skylar J. Ferrara, Priya Chaudhary, Margaret J. Debell, Gail Marracci, Hannah Miller, Evan Calkins, Edvinas Pocius, Brooke A. Napier, Ben Emery, Dennis Bourdette, Thomas S. Scanlan

Biology Faculty Publications and Presentations

Triggering receptor expressed on myeloid cells-2 (TREM2) is a cell surface receptor on macrophages and microglia that senses and responds to disease-associated signals to regulate the phenotype of these innate immune cells. The TREM2 signaling pathway has been implicated in a variety of diseases ranging from neurodegeneration in the central nervous system to metabolic disease in the periphery. Here, we report that TREM2 is a thyroid hormone-regulated gene and its expression in macrophages and microglia is stimulated by thyroid hormone and synthetic thyroid hormone agonists (thyromimetics). Our findings report the endocrine regulation of TREM2 by thyroid hormone, and provide a …

Go to article

Expression And Function Of Transcription Factors Foxa1, Hoxb13 And Cdx2 In Prostate Cancer, Hamsat B. Anwar Mar 2021

Expression And Function Of Transcription Factors Foxa1, Hoxb13 And Cdx2 In Prostate Cancer, Hamsat B. Anwar

University Honors Theses

Prostate cancer (PC) is the second leading cause of death in men, affecting around 190 thousand patients in 2020 alone (National Institute of Cancer, 2020). Much of the current research focuses on treatments for advanced PC, which is problematic due to the rapid evolution of tumors and development of treatment resistance. Cancer early detection presents a better approach to control and treat patients before they acquire an incurable disease. Earlier diagnosis of patients leads to better prognosis and a more comfortable treatment process (Etzioni et al., 2003). However, we currently lack molecular markers to stratify PC during its early stages. …

Go to article

Modulation Of Bacterial Fitness And Virulence Through Antisense Rnas, Jess A. Millar, Rahul Raghavan Feb 2021

Modulation Of Bacterial Fitness And Virulence Through Antisense Rnas, Jess A. Millar, Rahul Raghavan

Biology Faculty Publications and Presentations

Regulatory RNAs contribute to gene expression control in bacteria. Antisense RNAs (asRNA) are a class of regulatory RNAs that are transcribed from opposite strands of their target genes. Typically, these untranslated transcripts bind to cognate mRNAs and rapidly regulate gene expression at the post-transcriptional level. In this article, we review asRNAs that modulate bacterial fitness and increase virulence. We chose examples that underscore the variety observed in nature including, plasmid- and chromosome-encoded asRNAs, a riboswitch-regulated as RNA, and as RNAs that require other RNAs or RNA binding proteins for stability and activity. We explore how as RNAs improve bacterial fitness …

Go to article

A Rapid Caspase-11 Response Induced By Ifng Priming Is Independent Of Guanylate Binding Proteins, Sky W. Brubaker, Susan M. Brewer, Liliana M. Massis, Brooke A. Napier, Denise M. Monack Sep 2020

A Rapid Caspase-11 Response Induced By Ifng Priming Is Independent Of Guanylate Binding Proteins, Sky W. Brubaker, Susan M. Brewer, Liliana M. Massis, Brooke A. Napier, Denise M. Monack

Biology Faculty Publications and Presentations

In mammalian cells, inflammatory caspases detect Gram-negative bacterial invasion by binding lipopolysaccharides (LPS). Murine caspase-11 binds cytosolic LPS, stimulates pyroptotic cell death, and drives sepsis pathogenesis. Extracellular priming factors enhance caspase-11-dependent pyroptosis. Herein we compare priming agents and demonstrate that IFNγ priming elicits the most rapid and amplified macrophage response to cytosolic LPS. Previous studies indicate that IFN-induced expression of caspase-11 and guanylate binding proteins (GBPs) are causal events explaining the effects of priming on cytosolic LPS sensing. We demonstrate that these events cannot fully account for the increased response triggered by IFNγ treatment. Indeed, IFNγ priming …

Go to article

Developmental Programming Effects Of Maternal Obesity, Carolle J. Kassab May 2020

Developmental Programming Effects Of Maternal Obesity, Carolle J. Kassab

University Honors Theses

Population studies within the United States indicate increasing rates of obesity, considerably prominent for women within reproductive age. Maternal obesity is associated with the offspring’s hyperlipidemia, diabetes, and cardiovascular disease, which have chronic consequences. Obesity in pregnancy causes metabolic and epigenetic perturbations within the fetal environment, disrupting future health of offspring. This phenomenon is known as developmental programming. Although the relationship between maternal undernutrition and developmental programming has been demonstrated, its relationship to maternal obesity remains understudied.

Go to article

Cul3 Regulates Cyclin E1 Protein Abundance Via A Degron Located Within The N-Terminal Region Of Cyclin E, Brittney Marie Davidge, Katia De Oliveira Rebola, Larry N. Agbor, Curt D. Sigmund, Jeffrey D. Singer Nov 2019

Cul3 Regulates Cyclin E1 Protein Abundance Via A Degron Located Within The N-Terminal Region Of Cyclin E, Brittney Marie Davidge, Katia De Oliveira Rebola, Larry N. Agbor, Curt D. Sigmund, Jeffrey D. Singer

Biology Faculty Publications and Presentations

mammalian cells. Increased levels of cyclin E are found in some cancers. Additionally, proteolytic removal of the cyclin E N-terminus occurs in some cancers and is associated with increased cyclin E–Cdk2 activity and poor clinical prognosis. Cyclin E levels are tightly regulated and controlled in part through ubiquitin-mediated degradation initiated by one of two E3 ligases, Cul1 and Cul3. Cul1 ubiquitylates phosphorylated cyclin E, but the mechanism through which Cul3 ubiquitylates cyclin E is poorly understood. In experiments to ascertain how Cul3 mediates cyclin E destruction, we identified a degron on cyclin E that Cul3 targets for ubiquitylation. Recognition of …

Go to article

Genome Sequences Of Three Cruciviruses Found In The Willamette Valley (Oregon), Ignacio De La Higuera, Ellis L. Torrance, Alyssa A. Pratt, George Kasun, Amberlee Maluenda, Kenneth M. Stedman Jan 2019

Genome Sequences Of Three Cruciviruses Found In The Willamette Valley (Oregon), Ignacio De La Higuera, Ellis L. Torrance, Alyssa A. Pratt, George Kasun, Amberlee Maluenda, Kenneth M. Stedman

Biology Faculty Publications and Presentations

Cruciviruses are single-stranded DNA (ssDNA) viruses whose genomes suggest the possibility of gene transfer between DNA and RNA viruses. Many crucivirus genome sequences have been found in metagenomic data sets, although no crucivirus has been isolated. Here, we present the complete genome sequences of three cruciviruses recovered from environmental samples from Oregon.

Go to article

Disruption Of Cul3-Mediated Ubiquitination Causes Proximal Tubule Injury And Kidney Fibrosis, Turgay Saritas, Catherina A. Cuevas, Mohammed Z. Ferdaus, Christophe Kuppe, Rafael Kramann, Marcus J. Moeller, Jurgen Floege, Jeffrey Singer, James A. Mccormick Jan 2019

Disruption Of Cul3-Mediated Ubiquitination Causes Proximal Tubule Injury And Kidney Fibrosis, Turgay Saritas, Catherina A. Cuevas, Mohammed Z. Ferdaus, Christophe Kuppe, Rafael Kramann, Marcus J. Moeller, Jurgen Floege, Jeffrey Singer, James A. Mccormick

Biology Faculty Publications and Presentations

Cullin 3 (CUL3) is part of the ubiquitin proteasomal system and controls several cellular processes critical for normal organ function including the cell cycle, and Keap1/Nrf2 signaling. Kidney tubule-specific Cul3disruption causes tubulointerstitial fibrosis, but little is known about the mechanisms. Therefore, we tested the hypothesis that dysregulation of the cell cycle and Keap1/Nrf2 pathway play a role in initiating the kidney injury upon Cul3 disruption. Cul3 deletion increased expression of cyclin E and p21, associated with uncontrolled proliferation, DNA damage, and apoptosis, all of which preceded proximal tubule injury. The cdk2-cyclin E inhibitor roscovitine did not prevent the effects …

Go to article

Small Noncoding Rna Profiles Along Alternative Developmental Trajectories In An Annual Killifish, Amie L. Romney, Jason E. Podrabsky Sep 2018

Small Noncoding Rna Profiles Along Alternative Developmental Trajectories In An Annual Killifish, Amie L. Romney, Jason E. Podrabsky

Biology Faculty Publications and Presentations

Embryonic development of Austrofundulus limnaeus can occur along two phenotypic trajectories that are physiologically and biochemically distinct. Phenotype appears to be influenced by maternal provisioning based on the observation that young females produce predominately non-diapausing embryos and older females produce mostly diapausing embryos. Embryonic incubation temperature can override this pattern and alter trajectory. We hypothesized that temperature-induced phenotypic plasticity may be regulated by post-transcriptional modification via noncoding RNAs. As a first step to exploring this possibility, RNA-seq was used to generate transcriptomic profiles of small noncoding RNAs in embryos developing along the two alternative trajectories. We find distinct profiles of …

Go to article

Maternal Angiotensinogen Genotype And Fetal Sex Impact Uteroplacental Function And The Developmental Origins Of Stress-Induced Hypertension, Jessica Faith Hebert Jun 2018

Maternal Angiotensinogen Genotype And Fetal Sex Impact Uteroplacental Function And The Developmental Origins Of Stress-Induced Hypertension, Jessica Faith Hebert

Dissertations and Theses

Fetal growth restriction (FGR) is a common and potentially life-threatening complication that affects 5-10% of human pregnancies. Maternal genetic predisposition and fetal male sex are known risk factors, but the underlying mechanisms are unknown. To study a known maternal genetic risk factor and the impact of fetal sex, we employed a published transgenic (TG) mouse model, which was designed to mimic a common human angiotensinogen (AGT) promoter variant associated with a 20% increase in circulating AGT levels. We hypothesized that TG dams would deliver growth restricted pups and that the underlying mechanism would be related to differences in maternal uterine …

Go to article

Sexually Dimorphic Patterns Of Cell Proliferation In The Brain Are Linked To Seasonal Life-History Transitions In Red-Sided Garter Snakes, Deborah Lutterschmidt, Ashley R. Lucas, Ritta A. Karam, Vicky T. Nguyen, Meghann R. Rasmussen Jun 2018

Sexually Dimorphic Patterns Of Cell Proliferation In The Brain Are Linked To Seasonal Life-History Transitions In Red-Sided Garter Snakes, Deborah Lutterschmidt, Ashley R. Lucas, Ritta A. Karam, Vicky T. Nguyen, Meghann R. Rasmussen

Biology Faculty Publications and Presentations

Seasonal rhythms in physiology and behavior are widespread across diverse taxonomic groups and may be mediated by seasonal changes in neurogenesis, including cell proliferation, migration, and differentiation. We examined if cell proliferation in the brain is associated with the seasonal life-history transition from spring breeding to migration and summer foraging in a free-ranging population of red-sided garter snakes (Thamnophis sirtalis) in Manitoba, Canada. We used the thymidine analog 5-bromo-2′-deoxyuridine (BrdU) to label newly proliferated cells within the brain of adult snakes collected from the den during the mating season or from a road located along their migratory route. …

Go to article

Baseline Mrna Expression Differs Widely Between Common Laboratory Strains Of Zebrafish, Lindsay Holden, Kim H. Brown Jan 2018

Baseline Mrna Expression Differs Widely Between Common Laboratory Strains Of Zebrafish, Lindsay Holden, Kim H. Brown

Biology Faculty Publications and Presentations

Common strains of wildtype zebrafish (Danio rerio) have unique genomic features including SNPs and CNV, but strain information often goes unreported in the literature. As a result, the confounding effects of interstrain variation makes repetition of studies in zebrafish challenging. Here we analyze hepatic mRNA expression patterns between three common zebrafish strains (AB, Tuebingen (TU), and WIK) using Agilent 4 × 44 K gene expression microarrays to establish baseline mRNA expression across strains and between sexes. We observed wide variation in sex-specific gene expression within AB and WIK strains (141 genes in AB and 67 genes in WIK), …

Go to article

Investigating The Role Of Small Noncoding Rnas In Vertebrate Anoxia Tolerance, Claire Louise Riggs Dec 2017

Investigating The Role Of Small Noncoding Rnas In Vertebrate Anoxia Tolerance, Claire Louise Riggs

Dissertations and Theses

Very few vertebrates survive extended periods of time without oxygen. Entry into metabolic depression is central to surviving anoxia, which is supported by overall suppression of protein synthesis, yet requires increased expression of specific proteins. Studying the rapid and complex regulation of gene expression associated with survival of anoxia may uncover new mechanisms of cellular biology and transform our understanding of cells, as well as inform prevention and treatment of heart attack and stroke in humans. Small non-coding RNAs (sncRNAs) have emerged as regulators of gene expression that can be rapidly employed, can target individual genes or suites of genes, …

Go to article

Plasma Cell Survival In The Absence Of B Cell Memory, Erika Hammarlund, Archana Thomas, Ian J. Amanna, Lindsay Holden, Ov D. Slayden, Byung S. Park, Lina Gao, Mark K. Slifka Nov 2017

Plasma Cell Survival In The Absence Of B Cell Memory, Erika Hammarlund, Archana Thomas, Ian J. Amanna, Lindsay Holden, Ov D. Slayden, Byung S. Park, Lina Gao, Mark K. Slifka

Biology Faculty Publications and Presentations

Pre-existing serum antibodies play an important role in vaccine-mediated protection against infection but the underlying mechanisms of immune memory are unclear. Clinical studies indicate that antigen-specific antibody responses can be maintained for many years, leading to theories that reactivation/differentiation of memory B cells into plasma cells is required to sustain long-term antibody production. Here, we present a decade-long study in which we demonstrate site-specific survival of bone marrow-derived plasma cells and durable antibody responses to multiple virus and vaccine antigens in rhesus macaques for years after sustained memory B cell depletion. Moreover, BrdU+ cells with plasma cell morphology can be …

Go to article

The Cul3 Ubiquitin Ligase: An Essential Regulator Of Diverse Cellular Processes, Brittney Marie Davidge Aug 2017

The Cul3 Ubiquitin Ligase: An Essential Regulator Of Diverse Cellular Processes, Brittney Marie Davidge

Dissertations and Theses

Cul3 forms E3 ubiquitin ligase complexes that regulate a variety of cellular processes. This dissertation describes Cul3's role in several of these pathways and provides new mechanistic details regarding the role of Cul3 in eukaryotic cells. Cyclin E is an example of a protein that is regulated in a Cul3-dependent manner. Cyclin E is a cell cycle regulator that controls the beginning of DNA replication in mammalian cells. Increased levels of cyclin E are found in some cancers, in addition, proteolytic removal of the cyclin E N-terminus occurs in some cancers and is associated with tumorigenesis. Cyclin E levels are …

Go to article

Transcriptomic Analysis Of Maternally Provisioned Cues For Phenotypic Plasticity In The Annual Killifish, Austrofundulus Limnaeus, Amie L. Romney, Jason E. Podrabsky Apr 2017

Transcriptomic Analysis Of Maternally Provisioned Cues For Phenotypic Plasticity In The Annual Killifish, Austrofundulus Limnaeus, Amie L. Romney, Jason E. Podrabsky

Biology Faculty Publications and Presentations

Background: Genotype and environment can interact during development to produce novel adaptive traits that support life in extreme conditions. The development of the annual killifsh Austrofundulus limnaeus is unique among vertebrates because the embryos have distinct cell movements that separate epiboly from axis formation during early development, can enter into a state of metabolic dormancy known as diapause and can survive extreme environmental conditions. The ability to enter into diapause can be maternally programmed, with young females producing embryos that do not enter into diapause. Alternately, embryos can be programmed to “escape” from diapause and develop directly by both maternal …

Go to article

Insulin-Like Growth Factor Pathway Described In Austrofundulus Limnaeus Diapause And Escape Embryos, Steven Cody Woll Aug 2016

Insulin-Like Growth Factor Pathway Described In Austrofundulus Limnaeus Diapause And Escape Embryos, Steven Cody Woll

Dissertations and Theses

Development in the annual killifish Austrofundulus limnaeus can follow two distinct developmental trajectories. Typical development includes the entrance of embryos into a state of metabolic and developmental arrest termed diapause. Alternately, embryos can escape diapause and develop directly without pause. These two trajectories are characterized by differences in the rate and timing of developmental, morphological, and physiological traits. Insulin and Insulin-like growth factor (IGF) signaling (IIS) is known to regulate entrance into diapause in a variety of invertebrates. In this thesis I explore the possible role of IGFs in the regulation of development and diapause in embryos of A. limnaeus …

Go to article

Characterization Of The Role That Alternative Ribonucleotide Reductases Play In Restoring Replication In The Presence Of Hydroxyurea In Escherichia Coli, Michael Sadek Jun 2015

Characterization Of The Role That Alternative Ribonucleotide Reductases Play In Restoring Replication In The Presence Of Hydroxyurea In Escherichia Coli, Michael Sadek

PSU McNair Scholars Online Journal

DNA replication is essential for cells to grow and divide. Ribonucleotide reductase is an essential enzyme that is responsible for the formation of deoxyribonucleotides that are used in DNA synthesis during replication. Hydroxyurea is a chemotherapeutic agent that is thought to work by specifically inhibiting the ribonuceotide reductase to prevent replication. However, recent studies in E. coli have shown that following an initial period of inhibition, DNA synthesis then recovers in the presence of hydroxyurea, suggesting that the mode of death and cellular response to hydroxyurea is more complex than originally proposed. The E.coli genome encodes three ribonucleotide reductases that …

Go to article

Role Of Metabolic Shifts In Protection From Mutation Damage: Characterizing Mitochondrial Membrane Potential In C. Elegans Gas-1 Mutants, Lauren S. Muñoz-Tremblay Jun 2015

Role Of Metabolic Shifts In Protection From Mutation Damage: Characterizing Mitochondrial Membrane Potential In C. Elegans Gas-1 Mutants, Lauren S. Muñoz-Tremblay

PSU McNair Scholars Online Journal

Many terminal human diseases are caused by mutations affecting mitochondrial functioning. Mitochondria are essential organelles responsible for producing cellular energy, adenosine triphosphate (ATP) via oxidative phosphorylation (OXPHOS) at mitochondrial electron transport chains (ETC). Proper ETC functioning relies on maintenance of the electrochemical gradient essential for energy production, known as mitochondrial membrane potential (ΔψM). The inner mitochondrial membrane is the site of the ETC and is most closely in contact with the enzymatic processes occurring within the mitochondrial matrix. Mutations affecting protein components of the ETC are especially troublesome for organelle health. ETC mutants commonly express altered ΔψM, as well as …

Go to article

Reverse Gyrase Is Not Necessary For Survival Of Hyperthermophilic Archaeon Pyrococcus Furiosus, Farshid Taghizadeh, Michael S. Bartlett May 2015

Reverse Gyrase Is Not Necessary For Survival Of Hyperthermophilic Archaeon Pyrococcus Furiosus, Farshid Taghizadeh, Michael S. Bartlett

Student Research Symposium

Reverse gyrase is the only known topoisomerase enzyme with positive supercoiling activity on covalently-closed DNA. This positive supercoiling is required to prevent DNA from denaturation at high temperatures. The gene that codes for this protein is present in all hyperthermophiles and absent from all mesophilic and thermophilic genomes, suggesting that this enzyme is the only hyperthermophile-specific protein. To investigate if this protein is vital for the cells, we knocked out its gene from the genome of living organism Pyrococcus furiosus. Pyrococcus furiosus is a hyperthermophilic archaeon that grows between 70°C to 103°C with an optimum growth temperature of 100°C. …

Go to article

Phenotypic And Mutational Consequences Of Mitochondrial Etc Genetic Damage, Michael James Lue Mar 2015

Phenotypic And Mutational Consequences Of Mitochondrial Etc Genetic Damage, Michael James Lue

Dissertations and Theses

Genetic mutation is the ultimate source of new phenotypic variation in populations. The importance of mutation cannot be understated, and constitutes a significant evolutionary force. Although single mutations may have little to no impact on organismal performance or fitness, when multiplied across the total number of potential sites within the genome, mutation can have a large impact. Accurate measurement of the rates, molecular mechanisms, and distributions of effects of mutations are critical for many applications of evolutionary theory. Despite the importance of both deleterious and beneficial mutations, their genome-wide patterns and phenotypic consequences are poorly understood when considering the mitochondrial …

Go to article

Genes Affecting The Repair And Survival Of Escherichia Coli Following Psoralen-Induced Damage: A Dna Interstrand Crosslinking Agent, Anthonige Vidya Perera Mar 2015

Genes Affecting The Repair And Survival Of Escherichia Coli Following Psoralen-Induced Damage: A Dna Interstrand Crosslinking Agent, Anthonige Vidya Perera

Dissertations and Theses

Photoactivated psoralens and other agents that form DNA interstrand crosslinks are highly cytotoxic and are useful in treating a range of diseases, including vitiligo, psoriasis, and some forms of cancer. Unlike many lesions that damage only one strand of the duplex DNA, DNA interstrand crosslinks form covalent bonds with both strands. Thus, repairing these lesions is complicated both by the lack of an undamaged strand to serve as a template for resynthesis following excision, as well as the potential to form double strand breaks if both strands are incised. A number of models have proposed that repair is likely to …

Go to article

Next Last