Molecular Biology Commons^™

Cellular Uptake Mechanism Of Paclitaxel Nanocrystals, Iris K. Archer, Zhaohui Wang, Tonglei Li

The Summer Undergraduate Research Fellowship (SURF) Symposium

Therapeutic options for metastasized human cancer in current practice remain limited and, sadly, there is no cure for metastatic cancer. The typical approach, chemotherapy, has both low efficacy due to poor drug solubility, and cytotoxic side effects to healthy tissue when delivered indiscriminately. To address both of these issues, we are pursuing the use of nanocrystal formulations of current chemotherapeutic agents as delivery platforms. Herein, we have studied cellular uptake mechanisms in cancer cells of nanocrystals of a chemotherapeutic agent, paclitaxel. Our goal in this study is to determine whether the nanocrystals can be taken up via endocytosis, especially when …

Bacterial Transcription Factors Grea, Greb And Dksa: Characterization Of Their Interaction With Rna Polymerase And Molecular Mechanism Of Action, Andrey Parshin

Graduate School of Biomedical Sciences Theses and Dissertations

The activity of RNA polymerase (RNAP), the key enzyme of transcription process, is regulated by a large number of transcription factors acting at each step of the transcription cycle. Our research project is focused on studying the structure and function of bacterial transcript cleavage factors GreA, GreB and the stringent response regulator DksA. Gre factors bind in the secondary channel of RNAP in backtracked (inactive) ternary elongation complexes and stimulate the enzyme's intrinsic RNase activity, which is required for suppression of transcription pause and arrest, enhancement of transcription fidelity, and efficient promoter escape. DksA also acts through the RNAP secondary …

Genetic Engineering Of Black Cherry (Prunus Serotina) For Reproductive Sterility And Insect Pest Resistance, Ying Wang

Open Access Dissertations

Black cherry (Prunus serotina Ehrh.) is one of the most valuable hardwoods for high- end cabinetry, furniture, architectural millwork, paneling, and veneer. However, the damage caused by cambial-mining insect pests triggers gummosis in black cherry, a non-specific defense response in which resinous gum is deposited at the site of injury. The gum defects dramatically decrease the yield of high-quality black cherry lumber, and the value can be reduced by as much as 90%. The goal of this project was to optimize the transformation and in vitro rooting system, and to develop transgenic black cherry for reproductive sterility and insect pest …

Characterization Of Caxck31, A Bacterial Calcium/Proton Antiporter, Marc Robert Ridilla

Open Access Dissertations

To better understand a class of transporters known as Calcium/Cation Antiporters (CaCAs), the bacterial calcium/proton antiporter CAXCK31 was purified and characterized. New methods were developed for its heterologous overexpression and purification. These methods help to define stress responses to toxic membrane overproduction in E. coli and may be broadly applicable to studies of membrane proteins. The results from a variety of biochemical and biophysical experiments demonstrated that CAXCK31 exists as a dimer in the membrane and can be purified in the dimeric state. The methods used include chemical cross-linking, FRET, and SEC-MALS. In addition, various transport properties of CAXCK31, including …

Structural Studies On The Rubella Virus Capsid Protein And Its Organization In The Virion, Vidya Mangala Prasad

Open Access Dissertations

Rubella virus is a leading cause of birth defects due to infectious agents. When contracted during pregnancy, rubella infection leads to severe damage in fetuses. Despite its medical importance, very little is known about the structure of the pleomorphic rubella virus as compared to its alphavirus relatives. The rubella capsid protein is a critical structural component of virions as well as a key factor in virus-host interactions. Three crystal structures of the structural domain of the rubella capsid protein have been described here. The polypeptide fold of the capsid protomer has not been observed previously. The capsid protein structure, along …

The Termite Digestome: Understanding The Digestive Physiology Involved In Lignocellulosic Biomass Degradation, Zachary John Karl

Open Access Dissertations

The purpose of this research was to advance the understanding of lower termite digestive physiology and discover potential biocatalysts that can aid in the degradation of lignocellulosic biomass. Various protein characterization and gene expression methods were used throughout this research in order to accomplish these objectives. The results of this dissertation indicate that: 1) termites and their symbionts act in a synergistic manner to degrade biomass in vitro, 2) the host fraction of the gut (i.e., foregut and midgut) is the likely site of glucose absorption, 3) the termite and its symbionts contribute specific enzymes to the digestive process, 4) …

Generation And Statistical Modeling Of Active Protein Chimeras: A Sequence Based Approach, Nicholas Fico

Open Access Dissertations

Generation of active protein chimeras is a valuable tool to probe the functional space of proteins. Statistical modeling is the next logical step, allowing us to build a model of gene fragment replaceability between species. In this thesis I begin to develop the statistical tools that are needed to systematically describe combinatorial protein libraries. I present three sets of diverse chimeric protein libraries developed using sequence information. The statistical model of the human N-Ras and human K-Ras-4B genes reveal a set previously unidetifed surface residues on the N-Ras G-Domain that may be involved in cellular localization. Statistical modeling of a …

Identification Of Cell Cycle–Regulated Genes Periodically Expressed In U2os Cells And Their Regulation By Foxm1 And E2f Transcription Factors, Gavin D. Grant, Lionel Brooks Iii, Xiaoyang Zhang, J. Matthew Mahoney, Viktor Martyanov, Tammara A. Wood, Gavin Sherlock, Chao Cheng, Michael L. Whitfield

Dartmouth Scholarship

We identify the cell cycle–regulated mRNA transcripts genome-wide in the osteosarcoma-derived U2OS cell line. This results in 2140 transcripts mapping to 1871 unique cell cycle–regulated genes that show periodic oscillations across multiple synchronous cell cycles. We identify genomic loci bound by the G2/M transcription factor FOXM1 by chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) and associate these with cell cycle–regulated genes. FOXM1 is bound to cell cycle–regulated genes with peak expression in both S phase and G2/M phases. We show that ChIP-seq genomic loci are responsive to FOXM1 using a real-time luciferase assay in live cells, showing that FOXM1 strongly …

The Tethering Complex Hops Catalyzes Assembly Of The Soluble Snare Vam7 Into Fusogenic Trans-Snare Complexes, Michael Zick, William Wickner

Dartmouth Scholarship

The fusion of yeast vacuolar membranes depends on the disassembly of cis–soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE) complexes and the subsequent reassembly of new SNARE complexes in trans. The disassembly of cis-SNARE complexes by Sec17/Sec18p releases the soluble SNARE Vam7p from vacuolar membranes. Consequently, Vam7p needs to be recruited to the membrane at future sites of fusion to allow the formation of trans-SNARE complexes. The multisubunit tethering homotypic fusion and vacuole protein sorting (HOPS) complex, which is essential for the fusion of vacuolar membranes, was previously shown to have direct affinity for Vam7p. The …

Differential Biosynthesis Of Antioxidant Stilbenoids In Hairy Root Cultures Of Muscadine Grape And Peanut Treated With Methyl Jasmonate And Hydrogen Peroxide, Cesar Augusto Nopo-Olazabal

Student Theses and Dissertations

Stilbenoids are polyphenolic compounds that are believed to protect plants against abiotic and biotic stresses. Importantly, an increasing number of these specialized plant metabolites have been associated with potential health benefits in humans. Therefore, understanding the molecular mechanisms involved in their biosynthesis is of importance to enhance the levels of these beneficial compounds in plants. In this research we studied the biosynthesis of stilbenoids in two economically important food crops: muscadine grape and peanut. Hairy root cultures were used as biological systems because their genetic and biochemical stability facilitates the study of specialized metabolism. Selected hairy root cultures from muscadine …

Identification Of Proteins Potentially Involved In The Formation Of Lafora Bodies, A Hallmark Of Lafora Disease, Elham Schokraie, Oliver Kötting, Matthew S. Gentry

Molecular and Cellular Biochemistry Presentations

Lafora Disease (LD) is a fatal teenage-onset progressive myoclonus epilepsy. It is characterized by the formation of Lafora bodies (LBs), deposits of abnormally branched, insoluble, hyperphosphorylated glycogen-like polymers that are generally believed to trigger the development of the clinical symptoms of LD. 58% and 35% of the LD cases are caused by mutations in EPM2A (laforin) and EPM2B (malin), respectively. However, little is known about their function in LB formation. Two different mechanisms have been proposed to explain the accumulation of insoluble LBs: first, excessive glycogen phosphorylation and, second, an imbalance between glycogen synthesizing enzymes. The present study aims at …

Serdemetan Antagonizes The Mdm2-Hif1Α Axis Leading To Decreased Levels Of Glycolytic Enzymes, Jason Alexander Lehman, Paula M. Hauck, Jaimie M. Gendron, Christopher N. Batuello, Jacob A. Eitel, Allan Albig, Madhavi P. Kadakia, Lindsey D. Mayo

Biochemistry and Molecular Biology Faculty Publications

Serdemetan (JNJ-26854165), an antagonist to Mdm2, was anticipated to promote the activation of p53. While regulation of p53 by Mdm2 is important, Mdm2 also regulates numerous proteins involved in diverse cellular functions. We investigated if Serdemetan would alter the Mdm2-HIF1α axis and affect cell survival in human glioblastoma cells independently of p53. Treatment of cells with Serdemetan under hypoxia resulted in a decrease in HIF1α levels. HIF1α downstream targets, VEGF and the glycolytic enzymes (enolase, phosphoglycerate kinase1/2, and glucose transporter 1), were all decreased in response to Serdemetan. The involvement of Mdm2 in regulating gene expression of glycolytic enzymes raises …

Acrylamide Reduction In Potato Chips By Selection Of Potato Variety Grown In Iran And Processing Conditions, S. Shojaee-Aliabadi, Hooshang Nikoopour, Farzad Kobarfard, Mahdi Parsapour, Maryam Moslehishad, Hassan Hassanabadi, Jesus Maria Frias, Maryam Hashemi, Ezzat Dahaghin

Articles

Background

Acrylamide as a possible carcinogen is known to form in heated carbohydrate-rich food such as potato chips. In this study, the effect of three potato varieties (Agria, Sante and Savalan) and two blanching conditions ((75˚C for 9 min and 83˚C for 2.5 min) on the concentration of precursors and acrylamide reduction in potato chips was investigated.

Results

Results revealed that potato variety and blanching time-temperature ere important parameters for acrylamide formation in potato chips. Acrylamide content in Sante variety potatoes, which contained the highest amount of reducing sugars, was found to be the highest (8825μg/kg). However, Savalan, containing …

A Study On The Regulation Of Amino Acids And Glucose Sensing Pathways In Saccharomyces Cerevisiae, Mengying Chiang

LSU New Orleans Theses and Dissertations

Nutrient availability regulates eukaryotic cell growth. This study focuses on two signaling pathways, involved in sensing amino acids and carbon sources, which allow cells to respond appropriately to their presence. The first part of this study shows that Ssy1, a plasma membrane localized sensor in the Ssy1-Ptr3-Ssy5 (SPS) amino acid sensing pathway, can detect 19 common L-amino acids with different potencies and affinities based on the physiochemical structure of amino acids. Substituents around alpha carbon are critical for amino acid sensing by Ssy1. Furthermore, a high concentration of cysteine is toxic to cells. Inactivation of SPS signaling confers resistance to …

Sarcoptes Scabiei Mites Modulate Gene Expression In Human Skin Equivalents, Marjorie S. Morgan, Larry G. Arlian, Michael P. Markey

Biochemistry and Molecular Biology Faculty Publications

The ectoparasitic mite, Sarcoptes scabiei that burrows in the epidermis of mammalian skin has a long co-evolution with its hosts. Phenotypic studies show that the mites have the ability to modulate cytokine secretion and expression of cell adhesion molecules in cells of the skin and other cells of the innate and adaptive immune systems that may assist the mites to survive in the skin. The purpose of this study was to identify genes in keratinocytes and fibroblasts in human skin equivalents (HSEs) that changed expression in response to the burrowing of live scabies mites. Overall, of the more than 25,800 …

Preservation Of Biosignature Molecules In Potential Sample Return Container Of The Mars 2020 Mission, Kimberly E. Lykens, Fei Chen Ph.D

STAR Program Research Presentations

Preservation of Biosignature Molecules in Potential Sample Return Container of the Mars 2020 Mission

Kimberly Lykens¹ and Fei Chen²

¹Wittenberg University, Springfield, Ohio 45501 ²Jet Propulsion Laboratory, Pasadena, California, 91109

One requirement for sustainable life on terrestrial planets includes the presence of organic polymers, compounds that are essential for major biological functions such as replication and catalysis. An identified goal of the Mars mission in the year 2020 is to implement a sample-return to identify and validate signs of life on Mars through the discovery of biosignature molecules in Martian core samples. Martian core samples recovered …

Modulation Of Bax/Bak Dependent Apoptosis By Sirtuin 3 And Mitochondrial Permeability Transition By Sirtuin 4, Manish Verma

Graduate School of Biomedical Sciences Theses and Dissertations

Mitochondria are dynamic organelles that regulate a myriad of cellular functions, including energy production and metabolic regulation. Mitochondria are also a critical regulator of cell death signaling cascades modulating both apoptotic and necrotic cell death. However, what determines which cell death pathway is activated is still unclear. The mitochondrial/intrinsic pathway of apoptosis is dependent on the activation of pro-apoptotic proteins, Bax and Bak, which induce mitochondrial outer membrane permeabilization (MOMP). Once the integrity of outer mitochondrial membrane (OMM) is compromised, pro-apoptotic intermembrane space proteins like cytochrome c, Smac/Diablo, Omi/HtrA2 and AIF are released into the cytoplasm, which activates the post-mitochondrial …

Med13p Prevents Stress-Independent Mitochondrial Hyperfragmentation And Aberrant Apoptosis Activation In Saccharomyces Cerevisiae By Controlling Cyclin C Nuclear Localization, Svetlana Khakhina

Graduate School of Biomedical Sciences Theses and Dissertations

During aging, and as a result of environmental changes, cells are exposed to elevated levels of reactive oxygen species (ROS). High ROS levels induce lipid oxidation, protein aggregation, mitochondrial hyperfragmentation, DNA damage and programmed cell death (PCD), also called apoptosis. PCD is a highly regulated process and its misregulation has been linked to neurodegenerative diseases and cancer development.

Our hypothesis is that cyclin C plays a role in the initiation of apoptosis. During normal conditions, cyclin C represses the transcription of stress response genes (SRG). In response to stress, cyclin C translocates to the cytoplasm where it facilitates mitochondrial hyperfragmentation …

The Effects Of Growth Hormone And Thyroxine Treatment On The Insulin Signaling Of Female Ames Dwarf Mouse Skeletal Muscle Tissue, Andrew Do

HIM 1990-2015

Ames dwarf (df/df) mice are deficient in anterior pituitary hormones: growth hormone (GH), thyroid stimulating hormone (TSH), and prolactin (PRL) due to a spontaneous, homozygous mutation of prop1[superscript df] gene. These dwarf mice exhibit characteristics such as delayed growth and development coupled with delayed aging, increased lifespan, overall increased insulin sensitivity, as well as resistance to certain diseases and cancers. The mutant mice possess low blood glucose, low serum insulin, and lower body temperature. Their enhanced longevity (about 40-60% longer lifespan than normal mice) is associated with their GH deficiency and disruption in the somatotropic axis (GH/IGF-1 hormonal pathway) as …

Post-Injury Calcium Chelation Rescues Skeletal Muscle Regeneration In Mice, Matthew D. Magda

Honors Scholar Theses

During aging the ability of skeletal muscle to regenerate after injury wanes until muscle integrity cannot be maintained. In this study it is shown that calcium chelation can restore young-like regenerative ability in an aged mouse model of skeletal muscle regeneration.