Microbiology Commons^™

The Effects Of Trivalent Arsenicals And Thioredoxin Reductase Inhibitors On Selenium Metabolism In Lung Cell Culture Models, Sarah Ryann Talbot

Electronic Theses and Dissertations

Arsenic exposure, through various routes, is associated with the development of cancer of the skin, lung, liver, kidney, and bladder. Treatment of cells in culture with trivalent arsenicals has been shown to increase reactive oxygen species (ROS). In particular, monomethylarsonous acid (MMAIII), a trivalent metabolite of arsenite, is highly cytotoxic and possibly carcinogenic. Three trivalent arsenicals; arsenite, arsenic trioxide (ATO), and MMAIII, are also known inhibitors of the selenoprotein thioredoxin reductase (TrxR). Selenium, an essential micronutrient in mammals, is needed in the form of selenocysteine for activity of this enzyme and other selenoproteins. TrxR is part of a key component …

Mutations In Transmembrane Domains 1, 4 And 9 Of The Plasmodium Falciparum Chloroquine Resistance Transporter Alter Susceptibility To Chloroquine, Quinine And Quinidine, Roland A. Cooper, Kristan D. Lane, Bingbing Deng, Jianbing Mu, Jigar J. Patel, Thomas E. Wellems, Xinzhuan Su, Michael T. Ferdig

Biological Sciences Faculty Publications

Mutations in the Plasmodium falciparum chloroquine (CQ) resistance transporter (PfCRT) can result in verapamil-reversible CQ resistance and altered susceptibility to other antimalarials. PfCRT contains 10 membrane-spanning domains and is found in the digestive vacuole (DV) membrane of intraerythrocytic parasites. The mechanism by which PfCRT mediates CQ resistance is unclear although it is associated with decreased accumulation of drug within the DV. On the permissive background of the P. falciparum 106/1(K76) parasite line, we used single-step drug selection to generate isogenic clones containing unique pfcrt point mutations that resulted in amino acid changes in PfCRT transmembrane domains 1 (C72R, K76N, K76I …

Ammonium And Ergosterol Production And Chitinolytic Enzyme Activities Of Urban And Rural Isolates Of Two Common Decomposer Fungi, Hai Li

All-Inclusive List of Electronic Theses and Dissertations

Increased temperature in urban areas compared to rural areas is known as the urban heat island (UHi) effect. The effects of UHI on ecosystem processes can indicate the potential effects of global warming on processes such as organic matter decomposition and nutrient cycling, etc. It was reported that the urban isolates of two fungal species ( Chrysosporium pannorum and Trichoderma koningii) appeared to have adapted to higher temperatures in urban oak forest compared to rural isolates. Since these fungi decompose chitin, releasing ammonium, the apparent adaptation of these fungi to higher temperatures is probably due to increased chitinolytic enzyme activity …

Polymorphism Of Hla-Dr And Hla-Dq In Rheumatoid Arthritis Patients And Clinical Response To Methotrexate--A Hospital-Based Study, Azra Arif I Ali, Tariq Moatter, Jawed Altaf Baig, Ahmed Iqbal, Azmat Hussain, Mohammad Perwaiz Iqbal

Department of Biological & Biomedical Sciences

Objective: To investigate the frequency and distribution of DRB1 and DQB1 alleles in Patients with rheumatoid arthritis (RA) and analyze the relationship between clinical response to methotrexate (MTX) and the HLA-DR and HLA-DQ genotypes in these patients.
Methods: In this case-control study, the HLA-DRB1 and HLA-DQB1 polymorphism in 91 RA patients and 91 healthy controls was done using polymerase chain reaction and sequence specific primers.
Results: There was no statistical difference in frequencies of HLA-DRB1*03, DRB1*04, DRB1*07, DRB1*10, DRB1*11, DRB1*12, DRB1*13, DRB1*14, DRB1*15 and DRB1*16 genotypes between patients and controls. However, DRB1*01 was found to be significantly more common (p=0.015) …

Accumulation Of Phycotoxins In The Mussel Mytilus Galloprovincialis From The Central Adriatic Sea, Maja Pavela-Vrančić, Ivana Ujević, Živana Ninčević Gladan, Ambrose Furey

Physical Sciences Publications

Surveys of DSP (Diarrheic Shellfish Poisoning) toxin profiles in the mussel Mytilus galloprovincialis from coastal waters of the central Adriatic Sea, over the years 1995 to 2001, demonstrate that incidents of shellfish toxicity in this area are dominated by the occurrence of okadaic acid (OA) and a PTX derivative, 7-epi-pectenotoxin-2-seco acid (7-epi-PTX-2SA). Toxin composition and the relative ratio of toxic components in shellfish is in correlation with the occurrence of DSP producing organisms from the Dinophysis species along with Prorocentrum micans and Lingulodinium polyedrum. The occurrence of D. sacculus shortly before the appearance of OA in shellfish implicates its possible …

Membrane Organization And Multimeric Interactions Of The Aer Receptor In E. Coli, Divya Dashrathkumar Amin

Loma Linda University Electronic Theses, Dissertations & Projects

Escherichia coli swims toward niches ideal for generating maximum energy by monitoring the environment with the aerotaxis sensor, Aer. This receptor has an N-terminal PAS domain, which is a sensor module present in a variety of proteins from all kingdoms of life (including humans). To date, the mechanism of signaling from a PAS sensor domain to a single signaling receiver domain has not been resolved. In Aer, the PAS sensor is separated from the signaling region by a membrane anchor. Most "transmembrane prediction" programs forecast a single membrane span for this membrane anchor, but such a topology is inconsistent our …

In Vitro Expression And Purification Of Class I Mhc Molecules, Loi Cheng

Honors Scholar Theses

The major histocompatibility complex (MHC) is a gene family responsible for many critical functions of the immune system in most vertebrates. The MHC consists of three classes differentiated by their structure and function, and MHC class I encodes antigen binding proteins as well as chaperone and accessory proteins such as tapasin. The purpose of this project is to reconstitute several human MHC class I molecules in their peptide-filled and peptide-deficient forms, and to purify these proteins for biochemical study. The expressed proteins include wild type and mutant variants of the fusion protein human leukocyte antigen HLA-B*0801-fos, and human beta-2-microglobulin (β2m). …

Nanosecond Pulsed Electric Field Effects On Cell Cycle And Apoptosis, Emily H. Hall

Theses and Dissertations in Biomedical Sciences

Apoptosis, programmed cell death, is a highly regulated and complex pathway essential for embryonic development, immune-system function and maintenance of tissue homeostasis where cells induce their own cell death. Cells undergoing apoptosis exhibit a distinctive phenotype characterized by maintenance of membrane integrity, cell shrinkage, phosphatidylserine (PS) externalization at the plasma membrane, caspase protease activation, DNA fragmentation, release of cytochrome c from the mitochondrion, and membrane blebbing. An important regulatory protein in the apoptotic pathway is p53. The p53 protein functions to modulate the cell cycle by arresting cells in the G1 and G 2 phases to repair DNA damage, and/or …

Use Of Cerium Oxide Nanoparticles For Protection Against Radiation-Induced Cell Death, Jimmie Colon

Electronic Theses and Dissertations

The ability of engineered cerium oxide nanoparticles to confer radioprotection was examined. Rat astrocytes were treated with cerium oxide nanoparticles to a final concentration of 10 nanomolar, irradiated with a single 10 Gy dose of ionizing radiation and cell death was evaluated by propidium iodine uptake at 24 and 48 hours after radiation insult. Treatment of rat astrocytes with nanoceria resulted in an approximate 3-fold decrease in radiation induced death. These results suggest that the nanoceria are conferring protection from radiation induced cell death. Further experiments with human cells were conducted. Human normal and tumor cells (MCF-7 and CRL8798) were …

Characterization And Evaluation Of The Immunogenizity Of Chloroplast-Derived 19-Kilodalton C-Terminal Merozoite Surface Antigen 1 (Msp1) Of Plasmodium Yoelii Yoelii, Sushamadevi Kamarajugadda

Electronic Theses and Dissertations

Malaria is a protozoan disease caused in humans by four different species of the genus Plasmodium (P. falciparum, P. vivax, P. ovale, P. malarie) and in rodents by Plasmodium yoelii yoelii. It has been reported that 1.5 to 3 million deaths occur worldwide due to malaria and the DALY (Daily affected life years) reports about 0.76% of world population affected by the disease in some of the major countries like Africa, Asia, Latin America etc., Due to the development of resistance to drugs by the parasite, there is an urgent need and prime importance for the development of an effective …

Expression Of Heterologous Proteins In Transgenic Tobacco Chloroplasts To Produce A Biopharmaceutical And Biopolymer, Andrew Leon Devine

Electronic Theses and Dissertations

The chloroplast has been demonstrated to be an ideal compartment to accumulate certain proteins or their biosynthetic products that would be harmful if they were accumulated in the cytoplasm. Hyper-expression of foreign proteins in chloroplast transgenics has accumulated up to 46% total soluble protein, this is possible due to the ~100 chloroplast genomes per chloroplast and ~100 chloroplasts per cell which can therefore, contain up to 10,000 copies of the transgene. Maternal gene inheritance of plastids in most crop plants results in natural gene containment. Chloroplast transformation also eliminates positional effects that are frequently observed with nuclear transformation and no …

Regulation Of Apoptotic Alkalinization Through Phosphorylation Of Sodium Hydrogen Exchanger Via P38 Mitogen Activated Protein Kinase, Amy Greinier

Electronic Theses and Dissertations

Regulation of intracellular pH is responsible for many cellular processes, such as metabolism, cell cycle progression, and apoptosis. Many chemotherapeutic agents work by inducing target cells to undergo apoptosis, a cell death process still poorly understood. Previous studies demonstrated that a rise in intracellular pH activated apoptotic proteins leading to cytochrome C release. This "apoptotic alkalinization" occurred upon activation of the plasma membrane protein, sodium hydrogen exchanger-1 (NHE1), whose activity is regulated by the stress kinase p38 MAPK. In previous studies, upon cytokine withdrawal from cytokine-dependent lymphocytes induced the activity of the p38 MAP kinase which then phosphorylated the C-terminus …

Expression And Characterization Of Mycobacterium Paratuberculosis 19kda With Posttranslational Modification, Mitra Safavi-Khasraghi

Electronic Theses and Dissertations

Despite the fact that E. coli supports limited posttranslational modification, this bacterium has been universally used as the expression system of choice. Expression of modified proteins in E. coli may lead to expression of recombinant proteins that lack essential immunomodulatory or catalytic components essentials for infectious processes. Previously in our laboratory, pMptb#28 plasmid containing a 4.8 kb insert from M. paratuberculosis has been identified which expressed 16 kDa recombinant protein in E. coli and 19 kDa recombinant protein in Mycobacterium smegmatis. The objective of this study is to identify the ORF sequence, investigate possible posttranslational modification and characterize the protein …

Bioinformatic Analysis Of Solanaceae Chloroplast Genomes And Characterization Of An Arabidopsis Protein Disulfide Isomerase In Transgenic Tobacco Chloroplasts, Justin James Grevich

Electronic Theses and Dissertations

Throughout history, traditional plant breeding has been used to provide resistance to pests, disease and other forms of environmental stress, as well as to increase yield and improve upon quality and processing attributes. Over the last decade, the advancement in sequencing technology and bioinformatic analysis has unleashed a wealth of knowledge about chloroplast genetic organization and evolution. The lack of complete plastid genome sequences is one of the major limitations in advancing plastid genetic engineering to other useful crops. This is due to the fact that plastid genome sequences are essential for the identification of endogenous regulatory sequences and optimal …

Studies On The Novel Function Of Amyloid Precursor Protein In Glial Differentiation Of Neural Stem Cells, Young-Don Kwak

Electronic Theses and Dissertations

Although amyloid β (Aβ) deposition has been a hallmark of Alzheimer’s disease (AD), the physiological function of amyloid precursor protein (APP) is not clear. Our results suggested that high concentration of APP induces glial differentiation while physiological level of APP promotes migration and differentiation of neural stem cell (HNSC). HNSCs were mainly differentiated into astrocytes when they are transplanted into APP transgenic mouse brain or treated with a high concentration of secreted-type APP (sAPP) in culture. Staurosporine (STS) induced a distinctive astrocytic morphology in NT-2/D1 neural progenitor cells with expressions of APP and astrocyte-specific markers, glial fibrillary acidic protein (GFAP), …

Phospholipase A2mechanism Of Interfacial Activation,An Interdiscliplinary Approach, Kathleen N. Nemec

Electronic Theses and Dissertations

Phospholipase A2 (PLA2) is an enzyme that hydrolyzes the sn-2-ester bond of membrane phospholipids and liberates arachidonic acid, which is converted to eicosanoids that act as potent mediators of inflammation and allergy. As such this enzyme plays a crucial role in many homeostatic physiological and immunologic processes and disease progression. PLA2s undergo substantial increase in activity upon binding to cellular membranes. This effect of interfacial activation is well recognized, yet its structural and physical aspects are poorly understood. In this work, we have employed the interdisciplinary methods of molecular biology, biochemistry, biophysics, bioinformatics and computational biology, in order to elucidate …

Molecular Epidemiology Of Antibiotic Resistant Salmonella Enterica Strains From Different Animal And Human Sources In Ireland, David George Lee

Theses

In this study, 176 isolates of Salmonella were collected from different laboratories in Ireland. All isolates were confirmed to be of the genus Salmonella by performing bacteriological and biochemical tests. Briefly, all isolates were cultured onto XLD agar after which pure cultures were verified and stocked at this institute. Definitive identification was carried out using the API 20-E system and a separate urease test was also performed on all isolates. After confirmation of the genus, all isolates were prepared for antibiotic susceptibility testing and r-types were determined using sixteen antibiotics. Depending on the antibiotic resistance profiles, isolates were selected for …

Microorganisms Pumping Iron: Anaerobic Microbial Iron Oxidation And Reduction, Karrie A. Weber, Laurie A. Achenbach, John D. Coates

School of Biological Sciences: Faculty Publications

Iron (Fe) has long been a recognized physiological requirement for life, yet for many microorganisms that persist in water, soils and sediments, its role extends well beyond that of a nutritional necessity. Fe(II) can function as an electron source for iron-oxidizing microorganisms under both oxic and anoxic conditions and Fe(III) can function as a terminal electron acceptor under anoxic conditions for iron-reducing microorganisms. Given that iron is the fourth most abundant element in the Earth’s crust, iron redox reactions have the potential to support substantial microbial populations in soil and sedimentary environments. As such, biological iron apportionment has been described …

Isolation And Functional Mapping Of Human T-Cell Leukemia Virus Type 1 Tax Oncoprotein Dna-Damage Complexes, Sarah Saionz Durkin

Theses and Dissertations in Biomedical Sciences

Human T-cell Leukemia Virus Type 1 (HTLV-1) is a transforming retrovirus which causes Adult T-cell Leukemia (ATL) and HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP). Cellular transformation can be caused by a single viral trans-activating protein, Tax. Tax may contribute to transformation through interaction with components of the DNA damage response pathway, promoting cellular genomic instability. We examined cellular Tax complexes in an effort to elucidate potential protein-protein interactions that can model the Tax-induced molecular events.

We also investigated the role of post-translational modification in regulating Tax function. We employed a direct physical analysis of Tax complexes isolated from mammalian …

The Epigenomic Viewpoint On Cellular Differentiation Of Myeloid Progenitor Cells As It Pertains To Leukemogenesis, Vincent E. Sollars

Biochemistry and Microbiology

The new millennium has brought with it a surge of research in the field of epigenetics. This has included advances in our understanding of stem cell characteristics and mechanisms of commitment to cell lineages prior to differentiation. The nature of stem cells is similar to that of malignant cells in that they have unlimited self-renewal and protection from apoptosis, leading researchers to suspect that stem cells are the target of oncogenesis. This review will explore the idea of how epigenetic control of gene expression may contribute to mechanisms controlling differentiation of myeloid progenitor cells and its importance to our understanding …

Potential Microcin Production By Helicobacter Pylori Hpm8, Sarah R. Null

All-Inclusive List of Electronic Theses and Dissertations

Helicobacter pylori undergoes significant mutation during chronic infection. The organism adapts to its specific host allowing a selective advantage even after repeated exposure to new competing strains. Genetic drift does not fully explain the ability of some strains to outcompete pre-existing strains or newly introduced strains. The hypothesis behind this research is that H. pylori HPM8 produces a peptide encoded on a plasmid, pHPM8, which has antibacterial activity against other H. pylori strains. Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) was used to determine the stage of the growth cycle the peptide is being expressed. RT-PCR demonstrated peptide expression throughout the …

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

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

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). …

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

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

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 …

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 …

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 …

Effect Of Humic Substance Photodegradation On Bacterial Growth And Respiration In Lake Water, Alexandre M. Anesio, William Granéli, George R. Aiken, David J. Kieber, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

This study addresses how humic substance (HS) chemical composition and photoreactivity affect bacterial growth, respiration, and growth efficiency (BGE) in lake water. Aqueous solutions of HSs from diverse aquatic environments representing different dissolved organic matter sources (autochthonous and allochthonous) were exposed to artificial solar UV radiation. These solutions were added to lake water passed through a 0.7-μm pore-size filter (containing grazer-free lake bacteria) followed by dark incubation for 5, 43, and 65 h. For the 5-h incubation, several irradiated HSs inhibited bacterial carbon production (BCP) and this inhibition was highly correlated with H₂O₂ photoproduction. The H_{2 …}