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Full-Text Articles in Molecular Biology

High Resolution X-Ray And Neutron Crystallographic Studies Of Escherichia Coli Dihydrofolate Reductase, Brad C. Bennett Dec 2005

High Resolution X-Ray And Neutron Crystallographic Studies Of Escherichia Coli Dihydrofolate Reductase, Brad C. Bennett

Doctoral Dissertations

Dihydrofolate Reductases (DHFRs) have been identified in nearly every proteome and are essential for most biosynthetic pathways involving one-carbon transfer reactions due to their recycling of tetrahydrofolate (THF). They catalyze the NADPH-dependent reduction of dihydrofolate (DHF), producing THF. Inhibition of DHFR ultimately depletes cellular pools of THF; causing a reduced supply of thymine nucleotides for DNA synthesis, resulting in genomic instability and cell death. Therefore, DHFRs remain important drug targets in antimicrobial and chemotherapeutic treatments. Despite exhaustive investigation of E. coli chromosomal DHFR, controversy persists over the dynamics of regulatory loops (the Met20, the βF-βG, and the βG-βH) and the …


Chromosomal Localization Of The Islet Neogenesis Associated Protein (Ingap) Gene In Syrian Hamster By Tyramide Signal Amplification-Fluorescence In Situ Hybridization (Tsa-Fish), Sallie A. Smith Oct 2005

Chromosomal Localization Of The Islet Neogenesis Associated Protein (Ingap) Gene In Syrian Hamster By Tyramide Signal Amplification-Fluorescence In Situ Hybridization (Tsa-Fish), Sallie A. Smith

Biological Sciences Theses & Dissertations

Diabetes mellitus is a group of conditions characterized by hyperglycemia due to an inability to produce or properly utilize insulin. The majority of cases fall into two categories, Type I and Type 2. Type I results from the autoimmune destruction of pancreatic β-cells of the islets. The beta cells are the exclusive source of insulin and the patient becomes entirely dependent on exogenous insulin to survive. Patients with Type 2 are distinguished by insulin resistance, a condition that develops due to the inability of the body to effectively use the insulin being produced. The β-cells gradually lose their ability to …


The Antitumor Agent, Arglabin-Dma, Preferentially Induces Apoptosis In Human Colon Tumor Cells, Sung Wook Kwon Apr 2005

The Antitumor Agent, Arglabin-Dma, Preferentially Induces Apoptosis In Human Colon Tumor Cells, Sung Wook Kwon

Theses and Dissertations in Biomedical Sciences

Arglabin-DMA, an analog of farnesyl pyrophosphate (FPP), reportedly inhibits farnesyltransferase (FTase) directly by competitively blocking the binding of Ras protein and its posttranslational modification, as suggested in previous studies. But, the mechanisms by which Arglabin-DMA inhibits tumor growth in vivo and in vitro are still relatively poorly characterized. To determine the mechanism by which this drug inhibits tumor growth, the effects of Arglabin-DMA in two human colon tumor cell lines (mutant K-ras HCT 116 and wild-type ras HT-29) were explored on cell proliferation, apoptosis, and cell cycle kinetics in vitro. In cell viability studies, we showed that Arglabin-DMA …


Mechanisms Of Cell Death Initiated In Herpes Simplex Virus Thymidine Kinase Expressing Colon Tumor Cells Treated With Ganciclovir And Ucn-01, Christina Elizabeth Ahn Apr 2005

Mechanisms Of Cell Death Initiated In Herpes Simplex Virus Thymidine Kinase Expressing Colon Tumor Cells Treated With Ganciclovir And Ucn-01, Christina Elizabeth Ahn

Theses and Dissertations in Biomedical Sciences

Metastatic colon carcinoma is the second leading cause of death from malignancy in the United States, and development of more effective treatments is essential. Heterologous expression of Herpes Simplex Virus Thymidine Kinase (HSVtk) in combination with the prodrug, ganciclovir (GCV), has shown great promise for the genetic therapy of many cancers, but most patients have had only a partial or minimal response to the therapy. After screening a panel of two drug combinations, our laboratory has shown that the combination of GCV and the protein kinase inhibitor UCN-01 (7-hydroxystaurosporine) enhances tumor cell death more effectively than either drug alone. However …


Novel Protein-Protein Interactions Regulate The Proteolytic Activity Of The Pro- Apoptotic Serine Protease, Omi/Htra2, Supriya Singh Jan 2005

Novel Protein-Protein Interactions Regulate The Proteolytic Activity Of The Pro- Apoptotic Serine Protease, Omi/Htra2, Supriya Singh

Electronic Theses and Dissertations

Omi/HtrA2 is a mitochondrial serine protease with high homology to the bacterial HtrA proteins. Omi promotes caspase-dependent apoptosis by binding and degrading IAPs-inhibitor of apoptosis proteins. Omi can also induce caspase-independent apoptosis but the actual mechanism is still unknown. IAP's are not the only substrates cleaved by Omi. There are at least two more known substrates of Omi, the HAX-1 and the ped/pea-15 proteins. HS1-associated protein X-1 (HAX-1) is a mitochondrial protein, degraded by Omi after induction of caspase-dependent apoptosis. Ped/pea-15 is also an anti-apoptotic protein and is cleaved by Omi after induction of caspase-independent apoptosis. The proteolytic activity of …


The Effects Of Arsenic On Selenoprotein Biosythesis, Fanta Konate Jan 2005

The Effects Of Arsenic On Selenoprotein Biosythesis, Fanta Konate

Electronic Theses and Dissertations

Arsenic contamination of drinking water is a real public health problem in certain areas of South-East Asia where chronic exposure has been correlated to higher rates of lung, skin, bladder, kidney, and liver cancer. Although arsenic carcinogenicity is well established, the mechanism by which it induces cancer is poorly understood. Recent evidence suggests that oxidative stress could be a possible mechanism for the carcinogenic effects of arsenic. Selenium, in the form of selenocysteine, is necessary for the activity of several enzymes with a role in the defense against reactive oxygen species (ROS), primarily thioredoxin reductases (TrxR) and glutathione peroxidases (Gpx). …


A Novel Binding Interaction For The Paxillin Ld3 Motif: Paxillin Ld3 Mediates Merlin-Paxillin Binding At Paxillin Binding Domain 1, Sandra E. Beattie Geden Jan 2005

A Novel Binding Interaction For The Paxillin Ld3 Motif: Paxillin Ld3 Mediates Merlin-Paxillin Binding At Paxillin Binding Domain 1, Sandra E. Beattie Geden

Electronic Theses and Dissertations

Neurofibromatosis type 2, an autosomal dominant genetic disorder, causes predisposed individuals to develop various benign central and peripheral nervous system tumors. The characteristic tumors of this disease are schwannomas, which are tumors of the Schwann cells, typically on the vestibular nerve. These and the other associated tumors slowly compress nervous system structures causing deafness and loss of balance, resulting in an average life-span of less than 40 years. The product of the Nf2 gene is the protein named merlin or schwannomin. In individuals diagnosed with NF2, merlin is either absent or mutated to the point of inactivation. As such, merlin …


Real Time Rt-Pcr For Direct Detection Of Viable Mycobacterium Avium Subspecies Paratuberculosis In Chron's Disease Patients And Association Of Map Infection With Downregulation In Interferon-Gamma Receptor (Infg1) Gene In Crohn's Disease Patients, Mounir Chehtane Jan 2005

Real Time Rt-Pcr For Direct Detection Of Viable Mycobacterium Avium Subspecies Paratuberculosis In Chron's Disease Patients And Association Of Map Infection With Downregulation In Interferon-Gamma Receptor (Infg1) Gene In Crohn's Disease Patients, Mounir Chehtane

Electronic Theses and Dissertations

Association of Mycobacterium avium subspecies paratuberculosis (MAP) with Crohn's disease (CD) and not with ulcerative colitis (UC), two forms of inflammatory bowel disease (IBD), has been vigorously debated in recent years. This theory has been strengthened by recent culture of MAP from breast milk, intestinal tissue and Blood from patients with active Crohn's disease. Culture of MAP from clinical samples remained challenging due to the fastidious nature of MAP including its lack of cell wall in infected patients. The advent of real time PCR has proven to be significant in infectious disease diagnostics. In this study, real time reverse transcriptase …


Expression Of Hepatitis C Viral Non-Structural 3 Antigen In Transgenic Chloroplasts, Anubhuti Bhati Jan 2005

Expression Of Hepatitis C Viral Non-Structural 3 Antigen In Transgenic Chloroplasts, Anubhuti Bhati

Electronic Theses and Dissertations

Hepatitis C viral infection is the major cause of acute hepatitis and chronic liver disease and remains the leading cause of liver transplants (NIH). An estimated 180 million people are infected globally (WHO). There is no vaccine available to prevent hepatitis C. The treatment with antiviral drugs is expensive, accompanied with various side effects and is limited only to those at risk of developing advanced liver disease. The treatment is also effective in only about 30% to 50% of treated patients and still a high percentage of patients are resistant to therapy. Therefore, there is an urgent need for the …


Expression Of Cholera Toxin B Subunit-Rotavirus Nsp4 Enterotoxin Fusion Protein In Transgenic Chloroplasts, Anila Kalluri Jan 2005

Expression Of Cholera Toxin B Subunit-Rotavirus Nsp4 Enterotoxin Fusion Protein In Transgenic Chloroplasts, Anila Kalluri

Electronic Theses and Dissertations

Rotavirus, the major cause of life-threatening infantile gastroenteritis, is a member of the Reoviridae family and is considered to be the single most important cause of virus-based severe diarrheal illness in infants and young children particularly 6 months to 2 years of age in industrialized and developing countries. Infection in infants and young children is often accompanied by severe life threatening diarrhea, most commonly following primary infection. Diarrhea is the major cause of death among children around the world. Responsible for 4 to 6 million deaths per year according to the World Health Organization (WHO), diarrhea is especially dangerous for …


Selenotrisulfide Derivative Of Alpha-Lipoic Acid: Evaluation In A Cell Culture Model For Potential Use As A Topical Antioxidant, Melenie Lee Alonis Jan 2005

Selenotrisulfide Derivative Of Alpha-Lipoic Acid: Evaluation In A Cell Culture Model For Potential Use As A Topical Antioxidant, Melenie Lee Alonis

Electronic Theses and Dissertations

Selenium is a required micronutrient in mammalian cells. It is incorporated in the form of selenocysteine into selenoenzymes such as glutathione peroxidase and thioredoxin reductase, and is absolutely required for activity. Thioredoxin reductase is necessary for reduction of oxidized thioredoxin and therefore plays a major role in maintaining the redox status of the cell. Glutathione peroxidase is responsible for reducing peroxides into their corresponding alcohols and water. Together, these selenoenzymes constitute a significant part of the cell's arsenal to defend itself against oxidative stress. Exogenous sources of oxidative stress, such as UV radiation, are capable of generating reactive oxygen species …


Receptor Mediated Oral Delivery Of Bioencapsulated Green Fluorescent Protein Expressed In Transgenic Chloroplasts, Arati Limaye Jan 2005

Receptor Mediated Oral Delivery Of Bioencapsulated Green Fluorescent Protein Expressed In Transgenic Chloroplasts, Arati Limaye

Electronic Theses and Dissertations

The skyrocketing costs of prescription medicine in developed countries and their lack of availability in developing countries are the most challenging problems of human health. Primary reasons for such high cost are fermentation-based production, expensive purification methods, the need for low temperature storage and transportation and the delivery through sterile injections. Most of these expenses could be minimized or eliminated when therapeutic proteins are expressed and orally delivered via plant cells. Chloroplasts have the machinery to fold complex and biologically active eukaryotic proteins in the soluble chloroplast stromal compartment. Protein expression through chloroplast transformation system offers a number of advantages …


Tumor Response Tcf-4/Β-Catenin Regulatory Elements For Enhancing Cancer Gene Therapies, Saurabh Kumar Gupta Jan 2005

Tumor Response Tcf-4/Β-Catenin Regulatory Elements For Enhancing Cancer Gene Therapies, Saurabh Kumar Gupta

Theses and Dissertations in Biomedical Sciences

Mutations in the adenomatous polyposis coli gene are frequently associated with progression of colon carcinoma and most other types of epithelial carcinomas. This usually results in stabilization of β-catenin protein levels, followed by transactivation of Tcf-4/β-catenin responsive genes. The effectiveness of a Tcf-4/β-catenin transcriptional enhancer element in combination with a c-fos or carcinoembryonic antigen promoter was tested for its ability to act as a tumor specific regulator of gene expression in a panel of human tumor and normal cell lines. Luciferase reporter assays indicated enhanced activity of the Tcf-4/β-catenin transcriptional element only in tumor cell lines, with minimal activities in …


Regulation Of Sparc Gene Expression By The Activator Protein 1 Transcription Factor, Joseph William Briggs Jan 2005

Regulation Of Sparc Gene Expression By The Activator Protein 1 Transcription Factor, Joseph William Briggs

Theses and Dissertations in Biomedical Sciences

Overexpression of the c-Jun proto-oncogene in MCF7 breast cancer cells results in a variety of phenotypic changes related to malignant progression including a shift to estrogen independent growth, increased cell motility and invasion. Concurrent with these phenotypic changes are alterations to cellular gene expression patterns. One gene that becomes highly upregulated is SPARC (secreted protein acidic and rich in cysteine). Increased SPARC expression is associated with malignant progression in a variety of different cancers, although little is known regarding the mechanisms of SPARC gene regulation. Therefore, the objectives of this study were: (1) to determine the mechanisms by which c-Jun …


Characterization Of Photosynthetic Reaction Centers From Bradyrhizobium Strain Btai 1, Isaac P. Forquer Jan 2005

Characterization Of Photosynthetic Reaction Centers From Bradyrhizobium Strain Btai 1, Isaac P. Forquer

Browse all Theses and Dissertations

Photosynthetic rhizobia have been studied for about 15 years now. They are now considered to be metabolically aligned with a relatively recently discovered group of bacteria, the anoxygenic aerobic phototrophs (AAP’s).Rhizobia form symbiotic relationships with plants from the Fabaceae family. Photosynthetic rhizobia not only nodulate the roots, as most other rhizobia do, but they also form nodules on the stems of certain leguminous plants. The plant provides carbon to the bacteria and the bacteria provides the plant with soluble nitrogen fixed from the biologically inert but abundant atmospheric N2. A key question regarding photosynthetic rhizobia and other AAP’s derives from …