Microbiology Commons^™

Characterization Of Functional Domains Of Equine Infectious Anemia Virus Rev Suggests A Bipartite Rna-Binding Domain, Jae-Hyung Lee, Sean C. Murphy, Michael Belshan, Wendy O. Sparks, Yvonne Wannemuehler, Sijun Liu, Thomas J. Hope, Drena Dobbs, Susan Carpenter

Nebraska Center for Virology: Faculty Publications

Equine infectious anemia virus (EIAV) Rev is an essential regulatory protein that facilitates expression of viral mRNAs encoding structural proteins and genomic RNA and regulates alternative splicing of the bicistronic tat/rev mRNA. EIAV Rev is characterized by a high rate of genetic variation in vivo, and changes in Rev genotype and phenotype have been shown to coincide with changes in clinical disease. To better understand how genetic variation alters Rev phenotype, we undertook deletion and mutational analyses to map functional domains and to identify specific motifs that are essential for EIAV Rev activity. All functional domains are contained within the …

Talking To Themselves: Autoregulation And Quorum Sensing In Fungi, Deborah A. Hogan

Dartmouth Scholarship

Extracellular autoinducing compounds in the supernatants of microbial cultures were first recognized for their roles in the induction of genetic competence in gram-positive bacteria and in the regulation of light production in marine vibrios. In 1994, this form of population-level regulation in microbes was dubbed “quorum sensing” since it enabled bacterial cells to chemically measure the density of the surrounding population. Subsequently, many examples of cell density-dependent regulation by extracellular factors have been found in diverse microorganisms. The widespread incidence of diverse quorum-sensing systems strongly suggests that regulation in accordance with cell density is important for the success of microbes …

Farnesol Restores Wild-Type Colony Morphology To 96% Of Candida Albicans Colony Morphology Variants Recovered Following Treatment With Mutagens, Ellen C. Jensen, Jacob M. Hornby, Nicole E. Pagliaccetti, Chuleeon M. Wolter, Kenneth Nickerson, Audrey L. Atkin

Kenneth Nickerson Papers

Candida albicans is a diploid fungus that undergoes a morphological transition between budding yeast, hyphal, and pseudohyphal forms. The morphological transition is strongly correlated with virulence and is regulated in part by quorum sensing. Candida albicans produces and secretes farnesol that regulates the yeast to mycelia morphological transition. Mutants that fail to synthesize or respond to farnesol could be locked in the filamentous mode. To test this hypothesis, a collection of C. albicans mutants were isolated that have altered colony morphologies indicative of the presence of hyphal cells under environmental conditions where C. albicans normally grows only as yeasts. All …

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 …

A Dual-Genome Microarray For The Pea Aphid, Acyrthosiphon Pisum, And Its Obligate Bacterial Symbiont, Buchnera Aphidicola, Alex C. C. Wilson, Helen E. Dunbar, Gregory K. Davis, Wayne B. Hunter, David L. Stern, Nancy A. Moran

Biology Articles and Papers

Background

The best studied insect-symbiont system is that of aphids and their primary bacterial endosymbiont Buchnera aphidicola. Buchnera inhabits specialized host cells called bacteriocytes, provides nutrients to the aphid and has co-speciated with its aphid hosts for the past 150 million years. We have used a single microarray to examine gene expression in the pea aphid, Acyrthosiphon pisum, and its resident Buchnera. Very little is known of gene expression in aphids, few studies have examined gene expression in Buchnera, and no study has examined simultaneously the expression profiles of a host and its symbiont. Expression profiling …

Conserved Amino Acids Of The Human Immunodeficiency Virus Type 2 Vpx Nuclear Localization Signal Are Critical For Nuclear Targeting Of The Viral Preintegration Complex In Non-Dividing Cells, Michael Belshan, Lisa A. Mahnke, Lee Ratner

Nebraska Center for Virology: Faculty Publications

The HIV-2 viral accessory protein Vpx is related to, but distinct from the Vpr protein of HIV-1. Vpx is packaged into virions and as a component of the viral preintegration complex (PIC) is required for efficient virus replication in non-dividing cells. We have previously reported that the minimal transferable region of Vpx that contained karyophilic properties was aa 65 to 72. Analysis of Vpx sequences from various HIV-2/SIV strains reveals that this region contains highly conserved amino acids, including two basic residues (K68, R70) and three tyrosines (Y66, Y69, Y71). Here, we demonstrate that mutation of the basic or tyrosine …

Conservation Of The Pho Regulon In Pseudomonas Fluorescens Pf0-1, Russell D. Monds, Peter D. Newell, Julia A. Schwartzman, George A. O'Toole

Dartmouth Scholarship

The Pho regulon integrates the sensing of environmental inorganic phosphate (Pi) availability with coregulation of gene expression, mediating an adaptive response to Pi limitation. Many aspects of the Pho regulon have been addressed in studies of Escherichia coli; however, it is unclear how transferable this knowledge is to other bacterial systems. Here, we report work to discern the conservation of the Pho regulon in Pseudomonas fluorescens Pf0-1. We demonstrate by mutational studies that PhoB/PhoR and the Pst system have conserved functions in the regulation of Pi-induced phosphatase activities, as well as expression of other Pi-regulated genes. A genetic screen was …

Bacteriophage Migration Via Nematode Vectors: Host-Parasite-Consumer Interactions In Laboratory Microcosms, John J. Dennehy, Nicholas A. Friedenberg, Yul W. Yang, Paul E. Turner

Dartmouth Scholarship

Pathogens vectored by nematodes pose serious agricultural, economic, and health threats; however, little is known of the ecological and evolutionary aspects of pathogen transmission by nematodes. Here we describe a novel model system with two trophic levels, bacteriophages and nematodes, each of which competes for bacteria. We demonstrate for the first time that nematodes are capable of transmitting phages between spatially distinct patches of bacteria. This model system has considerable advantages, including the ease of maintenance and manipulation at the laboratory bench, the ability to observe many generations in short periods, and the capacity to freeze evolved strains for later …

Analysis Of Bacterial Population And Distribution In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Bioremediation, Milton J. Clausen Jr.

Theses and Dissertations

Chlorinated hydrocarbons and their degradation products are among of the most common organic groundwater contaminates in the United States. These compounds attack the central nervous system in animals and can affect the photosynthesis of plants. These compounds are also resistant to degradation in the environment and, because of this, pose a risk to any ecosystem in which they are present. This study identified the dominant microbial species in a constructed treatment wetland at Wright-Patterson AFB, Dayton, Ohio using 16S rRNA gene sequence analysis. Samples were taken from three different depths and during each of the four seasons. These samples were …

D-Mekk1, The Drosophila Orthologue Of Mammalian Mekk4/Mtk1, And Hemipterous/D-Mkk7 Mediate The Activation Of D-Jnk By Cadmium And Arsenite In Schneider Cells, Olga P. Ryabinina, Ezhilkani Subbian, Mihail S. Iordanov

CUP Faculty Research

Background: The family of c-Jun NH₂-terminal kinases (JNK) plays important roles in embryonic development and in cellular responses to stress. Toxic metals and their compounds are potent activators of JNK in mammalian cells. The mechanism of mammalian JNK activation by cadmium and sodium arsenite involves toxicant-induced oxidative stress. The study of mammalian signaling pathways to JNK is complicated by the significant degree of redundancy among upstream JNK regulators, especially at the level of JNK kinase kinases (JNKKK).

Results: Using Drosophila melanogaster S2 cells, we demonstrate here that cadmium and arsenite activate Drosophila JNK (D-JNK) via oxidative stress as …

First Report Of Ophthalmomyaisis Externa In Pakistan, Azam Ali, Agha Hassan Feroze, Paul Ferrar, Asad Abbas, Mohammad Asim Beg

Section of Ophthalmology

Two individuals presented to the Aga Khan University Opthalmology service with foreign-body sensation, pain and redness in one of their eyes. Slit-lamp biomicroscopy revealed tiny larvae crawling around the conjunctival sac. They were mechanically removed under topical anaesthesia and preserved for light microscopy and photography. Comprehensive liaison was established with the Australian Centre for International Agriculture Research for identification of these larvae. Their morphology characterized them as members of fruit-fly, Oestridae family. At least one of them was positively identified as first instar larva of Oestrus ovis. This report describes the first instance of such infections in Southern Pakistan, as …

Keeping Their Options Open: Acute Versus Persistent Infections, S. Furukawa, S. L. Kuchma, G. A. O'Toole

Dartmouth Scholarship

No abstract provided.

Comparison Of Two Methods (Precipitation Manual And Fully Automated Enzymatic) For The Analysis Of Hdl And Ldl Cholesterol, Jawaid Jabbar, Imran Siddiqui, Qaiser Raza

Department of Pathology and Laboratory Medicine

Objective:
To compare accuracy and throughput time for the measurement of HDL and LDL cholesterol by manual precipitation and fully automated enzymatic methods.
Methods:
Fifty, serum samples collected over a 4 months period (February - May 2004) were analyzed for HDL and LDL cholesterol by two different methods i.e. precipitation manual and automatic enzymatic method in the section of chemical pathology, Department of Pathology and Microbiology, Aga Khan University Hospital, Karachi Pakistan.
Results:
The mean standard deviation for HDL Cholesterol by precipitation method and automated method were 43.12 +/- 8.97mg/dl and 43.86 +/- 10.34mg/dl respectively (p-value = 0.301). The …

Transport Of E. Coli In Egyptian Agricultural Soils As A Result Of Reclaimed Wastewater Use For Irrigation, Aimen Badawy

Archived Theses and Dissertations

Limited water resources are one of the main constraints to socio-economic development and even a source of insecurity at national and regional levels. The increasing demand for water in the agricultural sector stimulated the use of reclaimed wastewater for irrigation. Comprehending health and environment risks resulting from contaminants that may often be associated with reclaimed wastewater will lead to the sustainable use of this resource, as well as the conservation of other water resources.

In the present study the fate and transport of one important wastewater constituent, namely E. Coli bacteria, in three Egyptian soils of typical agricultural use was …

Uneven Distribution Of Mhc Class Ii Epitopes Within The Influenza Virus, Sherry R. Crowe, Shannon C. Miller, Pamela S. Adams, Richard Dutton, Allen G. Harmsen, Frances E. Lund, Troy D. Randall, Deborah M. Brown, Susan Swain, David L. Woodland

Nebraska Center for Virology: Faculty Publications

The identification of T cell epitopes is crucial for the understanding of the host immune response during infection. While much is known about the MHC class I-restricted response following influenza virus infection of C57BL/6 mice, with over 16 CD8 epitopes identified to date, less is known about the MHC class II-restricted response. Currently, only a few I-A^b-restricted T helper epitopes have been identified. Therefore, several important questions remain about how many class II epitopes exist in this system and whether these epitopes are evenly distributed within the most abundant viral proteins. In order to address these questions, we …

Characterization Of The Role Of Sox9 In Cartilage-Specific Gene Regulation, Mary Ann Genzer

Theses and Dissertations

Although advances have been made toward understanding the complex mechanisms that regulate the process of DNA transcription, the specific mechanisms of activation for many individual genes remain unknown. In this study, we focus on the role the transcription factor SOX9 plays in activating cartilage-specific genes, specifically Col9a1 and Cartilage Link Protein (CRTL1). Previously, enhancers of these genes containing single SOX9 binding sites were shown to be activated through SOX9 binding. However, the hypothesis was made that in cartilage-specific genes dimeric SOX9, as opposed to monomeric SOX9, is necessary for activation. We identified a putative binding site adjacent to each of …

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 …

The Genetic Outcomes Of Sex And Recombination In Long-Term Functionally Parthenogenetic Lineages Of Australian Sitobion Aphids, Alex C. C. Wilson, Paul Sunnucks

Biology Articles and Papers

The typical life cycle of an aphid is cyclical parthenogenesis which involves the alternation of sexual and asexual reproduction. However, aphid life cycles, even within a species, can encompass everything on a continuum from obligate sexuality, through facultative sexuality to obligate asexuality. Loss of the sexual cycle in aphids is frequently associated with the introduction of a new pest and can occur for a number of environmental and genetic reasons. Here we investigate loss of sexual function in Sitobion aphids in Australia. Specifically, we aimed to determine whether an absence of sexual reproduction in Australian Sitobion results from genetic loss …

Prevalence And Serovars Of Salmonella In The Feces Of Free-Ranging White-Tailed Deer (Odocoileus Virginianus) In Nebraska, David G. Renter, David P. Gnad, Jan M. Sargeant, Scott E. Hygnstrom

School of Natural Resources: Faculty Publications

To determine the prevalence and serovars of Salmonella in free-ranging deer, we cultured feces from white-tailed deer (Odocoileus virginianus) harvested by hunters during a regular firearm season in southeastern Nebraska (USA). We recovered Salmonella from 5 (1%; 95% confidence interval: 0.37– 2.20%) of 500 samples and identified four different Salmonella enterica serovars [Litchfield (1), Dessau (1), Infantis (2), and Enteritidis (1)]. Although the prevalence of Salmonella in free-ranging deer appears to be low, the serovars recovered are known to be pathogenic to humans and animals.

Effects Of Feed Additives And Mixed Eimeria Species Infection On Intestinal Microbial Ecology Of Broilers, M. E. Hume, S. Clemente-Hernandez, E. O. Oviedo Rondon

Faculty Publications

Evaluation of digestive microbial ecology is necessary to understand effects of growth-promoting feed. In the current study, the dynamics of intestinal microbial communities (MC) were examined in broilers fed diets supplemented with a combination of antibiotic (bacitracin methylene disalicylate) and ionophore (Coban 60), and diets containing 1 of 2 essential oil (EO) blends, Crina Poultry (CP) and Crina Alternate (CA). Five treatments were analyzed: 1) unmedicated uninfected control; 2) unmedicated infected control; 3) feed additives monensin (bacitracin methylene disalicylate) + monensin (Coban 60; AI); 4) EO blend CP; and 5) EO blend CA. Additives were mixed into a basal feed …

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), …

Matrix Metalloproteinase-9 Amplifies The Immune Response To Pseudomonas Aeruginosa Corneal Infection, Sharon A. Mcclellan, Xi Huang, Ronald P. Barrett, Shahrzad Lighvani, Yunfan Zhang, Dawn Richiert, Linda D. Hazlett

Peer Reviewed Articles

PURPOSE. The purpose of this study was to determine the role of matrix metalloproteinases (MMP) in Pseudomonas aeruginosa keratitis.

METHODS. Gene array and selective real-time PCR examined MMP expression in the cornea of susceptible (C57BL/6, B6) versus resistant (BALB/c) mice before and after infection; zymography tested enzyme activity for MMP-2 and -9. Clinical score, Langerhans cell (LC), and Neutrophil (PMN) quantitation were done in recombinant (r) MMP-9, antibody neutralized, and MMP-9^−/− mice. The chemotactic potential of MMP-9 was tested in a Boyden chamber assay; light and transmission microscopy and immunostaining for collagen IV and MMP-9 were used …

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 …

Antibiotic Resistant And Coliform Bacteria In The Ohio River; 2002 To 2004, Lisa Marie Smith

Theses, Dissertations and Capstones

During 2002 and 2003 samples, collected every five miles along the Ohio River, were analyzed for total cultivable bacteria, ciprofloxacin resistant bacteria, erythromycin resistant bacteria, tetracycline resistant bacteria, and fecal coliforms. During 2004 samples were analyzed for total cultivable bacteria, ciprofloxacin resistant bacteria, sulfamethizole resistant bacteria, tetracycline resistant bacteria, Virginiamycin resistant bacteria, total coliforms, and Escherichia coli. The objectives of this study were to systematically collect data on fecal coliforms, E. coli, and antibiotic resistant bacteria in the Ohio River and its major tributaries; to determine if antibiotic resistance populations are correlated to each other or to coliforms; and …

Concomitant Antibiotic And Mercury Resistance Among Gastrointestinal Microflora Of Feral Brook Trout, Salvelinus Fontinalis, Matt Meredith

Undergraduate Research Symposium (UGRS)

No abstract provided.