Genetics and Genomics Commons^™

Mitochondrial Adaptation In The Green Crab Hybrid Zone Of The Gulf Of Maine, Jared Lynch

Honors Projects

The mitochondrial genome has historically been relegated to a neutral genetic marker, but new evidence suggests mitochondrial DNA to be a target for adaptation to environmental stress. The invasive European green crab (Carcinus maenas) exemplifies this in the Gulf of Maine’s hybrid zone, where interbreeding populations exhibit thermal tolerances influenced by mitochondrial genotype. To better understand the mechanism behind this phenomenon, the effect of mitochondrial genotype on mitochondrial activity was tested by measuring mtDNA copy number (mtCN) and the activity of complex I, II, and IV of the electron transport system via high-resolution respirometry. Mitochondria isolated from frozen …

The Role Of Parkin In Mitochondrial Dna, Eliezer Lichter

Theses & Dissertations

Mitochondria are at the center of biological phenomena such as aging and diseases, especially neurodegenerative diseases. While the discovery of mitochondria only came approximately 200 years after the cell was discovered, a lot of progress has been made since. The mitochondrial genome encodes proteins vital for mitochondrial function. These proteins are only a subset of the proteins present in mitochondria; the rest are nuclear encoded. The nucleus also encodes cytosolic proteins vital for mitochondrial maintenance. One of these is Parkin, an E3 ubiquitin ligase that ubiquitinates mitochondrial proteins as mitochondria become depolarized. Its activity has been shown to be involved …

Dpc29 Promotes Mitochondrial Translation Post-Initation In Saccharomyces Cerevisiae, Kyle Andrew Hubble

Graduate School of Biomedical Sciences Theses and Dissertations

Although the cytosolic and bacterial translation systems are well studied, much less is known about translation in mitochondria. In the yeast Saccharomyces cerevisiae, mitochondrial gene expression is predominately regulated by translational activators. These regulators are thought to promote translation by binding the elongated 5’-UTRs on their target mRNAs. Since mammalian mitochondrial mRNAs generally lack 5’-UTRs, they must regulate translation by other mechanisms. As expected, most yeast translational activators lack orthologues in mammals. Recently, a mitochondrial gene-specific translational activator, TACO1, was reported in mice and humans. To better define its role in mitochondrial translation I examined the yeast TACO1 orthologue, DPC29. …

Using Fluorescent Microscopy To Follow Mitochondrial Inheritance Through Tagged Alternative Oxidase In Sporisorium Reilianum., Luke Schroeder

College of Arts & Sciences Senior Honors Theses

Sporisorium reilianum is a dimorphic fungus that inhabits and infects a host corn plant (Zea mays). In order for the fungus to reproduce sexually, compatible haploid mating types must form a dikaryon that goes on to cause infection in the host. This infection causes leaf chlorosis and gall formation, while ultimately allowing for the dispersal of fungal teliospores in the later stages of infection. To grow, the fungus requires energy production in the form of ATP from its mitochondria. As a countermeasure to infection, host plants release harsh reactive oxygen species that may damage DNA, lead to apoptosis, …

Investigation Of Mitochondrial Inheritance In The Smut Fungus Sporisorium Reilianum., Hector Eduardo Mendoza

Electronic Theses and Dissertations

An important goal in evolutionary biology is to address the origin of Earth’s immense biodiversity through the evolution of complex sexual reproduction mechanisms in eukaryotes. Inheritance of mitochondria during sexual reproduction has received special attention in recent years, as these organelles cannot be synthesized de novo and must be transmitted from parent to offspring. The importance of these organelles far exceeds its common function as the energy-producing “powerhouse” of the cell, as it has been found to also be involved in fundamental processes like apoptosis, aging and metabolic homeostasis. Thus, appropriate inheritance of mitochondria is essential for growth and development …

Transactivation And Mitochondrial Activity Are Affected By High Temperature In C. Elegans Sperm, Jacqueline Mcvay

Scripps Senior Theses

Sexual reproduction has a conserved flaw in that it is temperature sensitive. Exposure to high temperature leads to male infertility, but little is known about the underlying mechanism. Understanding these mechanisms is important for agriculture and reproductive medicine. Using C. elegans, we investigated two potential aspects of male fertility that may be affected by high temperature conditions: activation of sperm by seminal fluid and sperm mitochondrial activity. There are two pathways for sperm activation in C. elegans: the SPE-8 pathway in hermaphrodites and the TRY-5 pathway in male seminal fluid. Hermaphrodite sperm with a mutation in spe-8 can …

Mnrr1: Understanding The Role Of A Novel Mitochondrial-Nuclear Regulator, Stephanie L. Gladyck

Wayne State University Dissertations

Mitochondria are complex organelles that generate most of the energy required to sustain life and function in metabolic and signaling pathways required to maintain cellular homeostasis. MNRR1 (mitochondrial nuclear retrograde regulator 1 or CHCHD2) is a small, bi-organellar twin CX9C protein that is emerging as an important regulator of mitochondrial function, apoptosis, and cellular stress by participating in mitochondrial-nuclear crosstalk. Our lab has previously shown that in the mitochondria, MNRR1 regulates complex IV (Cytochrome c oxidase or COX) and is able to finetune the oxidase function through phosphorylation status. We have also shown that during stress, mitochondrial MNRR1 levels deplete, …

Maternal Engineered Nanomaterial Inhalation Exposure: Cardiac Molecular Reprogramming In Progeny Through Epigenetic And Epitranscriptomic Mechanisms, Amina Kunovac

Graduate Theses, Dissertations, and Problem Reports

Introduction: Nano-titanium dioxide (TiO₂), a prominently utilized engineered nanomaterial (ENM), is being employed for its physiochemical properties in several fields including the food industry, manufacturing, and biomedicine. As the prevalence of this ENM, and other particulate matter grows, so does the concern for antagonistic consequences on long-term heart function in vulnerable populations, which until now have not been investigated. Due to the reliance of the heart on the ATP generating capacity of mitochondria for contraction, understanding the role of mitochondrial bioenergetics and structure is pivotal in understanding the repercussions of particulate matter exposure during gestation. As the mass …

Identifying Phenotypic Effects In Sporisorium Reilianum And Ustilago Maydis Lacking The Alternative Oxidase Gene., Caroline D. Culver

College of Arts & Sciences Senior Honors Theses

Ustilago maydis and Sporisorium reilianum are both dimorphic fungi that cause infection in the host plant, corn (Zea mays). In order for infection to be successful, compatible haploid mating types must form a dikaryon that later leads to the development and dispersal of teliospores. In order to sustain growth, energy is produced via the electron transport chain within the mitochondrion. Host plants often produce harsh reactive oxygen species, resulting in the need to use an alternative respiration pathway such as employing an alternative oxidase. Therefore, this study attempted to investigate the role of the aox gene in pathogenicity …

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, …

Hypoglycemia In Mitochondrial Disorders, Allison Moats

Dissertations & Theses (Open Access)

INTRODUCTION: The electron transport chain (ETC) in mitochondria functions to produce energy in the form of adenosine triphosphate (ATP). Defects in the mitochondrial or nuclear DNA that codes for components of the ETC lead to mitochondrial disorders (MTDs). MTDs are multi-system conditions affecting the heart, muscles, and especially brain. The endocrine system is commonly affected in MTDs, and diabetes and hyperglycemia are established secondary diagnoses. Rates of non-iatrogenic hypoglycemia have not been studied in individuals with MTDs. This study aims to investigate the frequency of hypoglycemia in patients with MTDs.

METHODS: Individuals diagnosed with a ‘definite’ or ‘probable’ …

Effects Of Commercial Formulations Of Glyphosate On Saccharomyces Cerevisiae, Apoorva Ravi Shankar

Graduate Theses, Dissertations, and Problem Reports

Commercial formulations of glyphosate are among the most extensively used herbicides around the world. The active ingredient, glyphosate, targets the aromatic amino acid pathway. This pathway is absent in mammals, resulting in low toxicity. Different formulations contain varying adjuvants and surfactants, whose synergistic effects are yet to be extensively studied at the cellular level. In this study, I tested multiple commercial formulations that showed a variation in growth phenotype among different yeast strains. To gain a better understanding of response and resistance mechanisms at the genome and transcriptome level, I carried out an in-lab evolution study, along with a transcriptome …

Expression Of Alternative Oxidase In The Copepod T. Californicus When Exposed To Environmental Stressors, Carly Tward

Theses and Dissertations (Comprehensive)

In addition to the typical electron transport system in animal mitochondria responsible for oxidative phosphorylation, some species possess an alternative oxidase (AOX) pathway, which causes electrons to bypass proton pumping complexes. Although AOX appears to be energetically wasteful, studies have revealed its wide taxonomic distribution, and indicate it plays a role in environmental stress tolerance. AOX discovery in animals is recent, and further research into its expression, regulation, and physiological role has been impeded by the lack of an experimental model organism. DNA database searches using bioinformatics revealed an AOX sequence present in the arthropod Tigriopus californicus. Multiple sequence …

Genetic Basis Of Thermal Divergence In Saccharomyces Species, Xueying C. Li

Arts & Sciences Electronic Theses and Dissertations

The genetic architecture of phenotypic divergence is a central question in evolutionary biology. Genetic architecture is impacted by whether evolution occurs through accumulation of many small-effect or a few large-effect changes, the relative contribution of coding and cis-regulatory changes, and the prevalence of epistatic effects. Our empirical understanding of the genetic basis of evolutionary change remains incomplete, largely because reproductive barriers limit genetic analysis to those phenotypes that distinguish closely related species. In this dissertation, I use hybrid genetic analysis to examine the basis of thermal divergence between two post-zygotically isolated species, Saccharomyces cerevisiae and S. uvarum. S. cerevisiae is …

Assisted Reproductive Technologies Disrupt Genomic Imprinting In Human And Mitochondria In Mouse Embryos, Carlee R. White

Electronic Thesis and Dissertation Repository

Infertile couples worldwide use assisted reproductive technologies (ARTs) to help conceive their own biological child. Due to the rising use of ARTs, there is continual emergence of new techniques implemented in human fertility clinics. When treatment is successful, there is an increased risk even within singletons for perinatal complications including preterm birth, intrauterine growth restriction, low and high birth weight and genomic imprinting disorders Beckwith Wiedemann Syndrome, Angelman Syndrome, and Silver-Russel Syndrome. Consequently, there is a need to investigate the effects of these treatments on the manipulated oocyte and preimplantation embryo. To address this, I first analyzed the combined effects …

Axonal Transport And Life Cycle Of Mitochondria In Parkinson's Disease Model, Hyun Sung

Open Access Dissertations

In neurons, normal distribution and selective removal of mitochondria are essential for preserving compartmentalized cellular function. Parkin, an E3 ubiquitin ligase associated with familial Parkinson’s disease, has been implicated in mitochondrial dynamics and removal. However, it is not clear how Parkin plays a role in mitochondrial turnover in vivo, and whether the mature neurons possess a compartmentalized Parkin-dependent mitochondrial life cycle. Using the live Drosophila nervous system, here, I investigate the involvement of Parkin in mitochondrial dynamics; organelle distribution, morphology and removal. Parkin deficient animals displayed less number of axonal mitochondria without disturbing organelle motility behaviors, morphology and metabolic state. …

A Mechanistic Study Of An Ipsc Model For Leigh’S Disease Caused By Mtdna Mutataion (8993 T>G), John P. Galdun

Theses and Dissertations

Mitochondrial diseases encompass a broad range of devastating disorders that typically affect tissues with high-energy requirements. These disorders have been difficult to diagnose and research because of the complexity of mitochondrial genetics, and the large variability seen among patient populations. We have devised and carried out a mechanistic study to generate a cell based model for Leigh’s disease caused by mitochondrial DNA mutation 8993 T>G. Leigh’s disease is a multi-organ system disorder that depends heavily on the mutation burden seen within various tissues. Using new reprogramming and sequencing technologies, we were able to show that Leigh’s disease patient fibroblasts …

Functional Significance Of Mtdna Cytosine Modification Tested By Genome Editing, Jason M. Robinson

Theses and Dissertations

The field of epigenetics is gaining popularity and speed, due in part to its capability to answer lingering questions about the root cause of certain diseases. Epigenetics plays a crucial role in regulation of the cell and cell survival, particularly by cytosine methylation. It remains controversial if DNMT’s which facilitate methylation are present in mammalian mitochondria and what the functional significance they may have on modification of mitochondrial DNA. CRISPR-Cas9 technology enabled genome editing to remove the MTS (mitochondrial targeting sequence) from DNMT1 of HCT116 cells, purposefully minimizing effects on nuclear cytosine methylation, while exclusively impacting mitochondrial modification. Removal of …

Causes And Consequences Of Mitochondrial Variation In Caenorhabditid Nematodes, Kiley Ann Hicks

Dissertations and Theses

Mitochondria are dynamic organelles that harbor their own stream-lined genome and generate much of the ATP necessary to sustain eukaryotic life via an electron transport chain (ETC). Because of the central role for mitochondria in organismal physiology, mitochondrial genetic and phenotypic variation can alter organismal fitness and affect population genetic and evolutionary outcomes. Despite the far-reaching relevance of mitochondria to evolutionary processes and human health, we lack a basic understanding of the causes and consequences of mitochondrial genetic and phenotypic variation. In this thesis, I quantified mitochondrial reactive oxygen species (ROS), membrane potential (δΨM), and mitochondrial morphological traits within Caenorhabditis …

Solid Phase Extraction Of Mammalian Cell Mitochondrial Dna And Its Electrophoretic Separation In Agarose Gels, Theresa Brick-Miller

Biological Sciences Theses & Dissertations

An improved and efficient electrophoretic procedure for the isolation of mitochondrial DNA (mtDNA) is described. The solid phase extraction procedure for the isolation of mtDNA involves embedding as few as 200,000 Ehrlich ascites tumor cells into a block of agarose, digestion of cellular membranes by detergent action and subsequent electrophoretic separation of nucleic acids in agarose gels. Genomic DNA remains in the original block of agarose while the mtDNA migrates in the separation gel to a position equivalent to that obtained for mtDNA isolated by traditional procedures.

The efficacy of a large number of detergents, agarose concentrations, embedding conditions, embedding …