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Cell and Developmental Biology Commons

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Portland State University

2015

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Articles 1 - 8 of 8

Full-Text Articles in Cell and Developmental Biology

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 …


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 …


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. …


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 …


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 …


Gene Expression Patterns That Support Novel Developmental Stress Buffering In Embryos Of The Annual Killifish Austrofundulus Limnaeus, Josiah T. Wagner, Jason E. Podrabsky Jan 2015

Gene Expression Patterns That Support Novel Developmental Stress Buffering In Embryos Of The Annual Killifish Austrofundulus Limnaeus, Josiah T. Wagner, Jason E. Podrabsky

Biology Faculty Publications and Presentations

Background: The cellular signaling mechanisms and morphogenic movements involved in axis formation and gastrulation are well conserved between vertebrates. In nearly all described fish, gastrulation and the initial patterning of the embryonic axis occur concurrently with epiboly. However, annual killifish may be an exception to this norm. Annual killifish inhabit ephemeral ponds in South America and Africa and permanent populations persist by the production of stress-tolerant eggs. Early development of annual killifish is unique among vertebrates because their embryonic blastomeres disperse randomly across the yolk during epiboly and reaggregate several days later to form the embryo proper. In addition, annual …


A Coxiella-Like Endosymbiont Is A Potential Vitamin Source For The Lone Star Tick, Todd A. Smith, Timothy Driscoll, Joseph J. Gillespie, Rahul Raghavan Jan 2015

A Coxiella-Like Endosymbiont Is A Potential Vitamin Source For The Lone Star Tick, Todd A. Smith, Timothy Driscoll, Joseph J. Gillespie, Rahul Raghavan

Biology Faculty Publications and Presentations

Amblyomma americanum (Lone star tick) is an important disease vector in the United States. It transmits several human pathogens, including the agents of human monocytic ehrlichiosis, tularemia, and southern tick-associated rash illness. Blood-feeding insects (Class Insecta) depend on bacterial endosymbionts to provide vitamins and cofactors that are scarce in blood. It is unclear how this deficiency is compensated in ticks (Class Arachnida) that feed exclusively on mammalian blood. A bacterium related to Coxiella burnetii, the agent of human Q fever, has been observed previously within cells of A. americanum. Eliminating this bacterium (CLEAA, Coxiella-like endosymbiont of A. americanum) with antibiotics …


Mathematical Model For Bone Mineralization, Svetlana V. Komarova, Lee Safranek, Jay Gopalakrishnan, Miao-Jung Yvonne Ou, Marc D. Mckee, Monzur Murshed, Frank Rauch, Erica Zuhr Jan 2015

Mathematical Model For Bone Mineralization, Svetlana V. Komarova, Lee Safranek, Jay Gopalakrishnan, Miao-Jung Yvonne Ou, Marc D. Mckee, Monzur Murshed, Frank Rauch, Erica Zuhr

Mathematics and Statistics Faculty Publications and Presentations

Defective bone mineralization has serious clinical manifestations, including deformities and fractures, but the regulation of this extracellular process is not fully understood. We have developed a mathematical model consisting of ordinary differential equations that describe collagen maturation, production and degradation of inhibitors, and mineral nucleation and growth. We examined the roles of individual processes in generating normal and abnormal mineralization patterns characterized using two outcome measures: mineralization lag time and degree of mineralization. Model parameters describing the formation of hydroxyapatite mineral on the nucleating centers most potently affected the degree of mineralization, while the parameters describing inhibitor homeostasis most effectively …