Microbiology Commons^™

Combination Of Virb Binding Site Mutations To Evaluate Collective Impact On Icsp Promoter Activity In Shigella Flexneri, Pashtana Usufuzy, Juan C. Duhart, Maria I. Castellanos, Helen Wing

Undergraduate Research Opportunities Program (UROP)

Shigella flexneri is a gram-negative, invasive bacterial pathogen that afflicts the human colonic epithelium, causing shigellosis, an illness triggering severe dysentery. The World Health Organization cites the disease burden of shigellosis near 90 million episodes and 108,000 deaths per year.

The motility and spread of Shigella is modulated by icsP, a virulence gene. The transcription factor VirB positively regulates many virulence genes encoded by the Shigella virulence plasmid. Two distal binding sites of VirB have been shown to regulate the promoter activity of icsP, despite their location of more than 1 kb upstream of the transcription start site. Five VirB …

Identification Of Nitrifying Bacteria Contained In A Commercial Inoculant Using Molecular Biology Techniques, Anthony Harrington, John Perry, Penny S. Amy

Undergraduate Research Opportunities Program (UROP)

Nitrifying bacteria play an important role in aquatic and terrestrial environments through the nitrogen cycle. Nitrification, one of the processes of the nitrogen cycle, refers to the oxidation of ammonia to nitrate. This process requires two types of chemoautotrophic bacteria, ammonia-oxidizing bacteria (AOB), and nitrite-oxidizing bacteria (NOB). These bacteria are essential in maintaining an optimal environment for plants and aquatic organisms, such as fish. Current applications of nitrifiers include: inoculants for aquariums, biofertilizers, and nitrogen removal in wastewater treatment plants. This study wants to identify a consortium of nitrifers that can be used to produce sufficient nitrate for plants in …

Biological Effects On Serpentinite Weathering, Mary H. Evert, Julie Baumeister, Elisabeth Hausrath

Undergraduate Research Opportunities Program (UROP)

Serpentinites, perhaps more than any other rock type, control the composition and evolution of the development of the surrounding ecosystems. The bulk chemistry of serpentinite rocks, high in Mg and trace elements, and low in nutrients such as Ca, K, P, and N, causes an extreme and stressful environment for ecosystems. However, the role that those serpentine ecosystems play in development of serpentine soils has not been examined.

Due to the unusual chemistry of serpentine soils, serpentine ecosystems have deeper and better-developed root systems than other ecosystems. The rhizosphere of serpentine systems, documented to produce abundant organic acids and siderophores, …

Inactivation Of Spo0a Gene Increases Stationary Phase Mutagenesis In Bacillus Subtilis, Denisse Reyes, Amanda Prisbrey, Holly Martin, Eduardo Robleto

Undergraduate Research Opportunities Program (UROP)

Stationary phase mutagenesis occurs when a population of cells acquires mutations conferring escape from nongrowing or stress conditions. This type of mutations is observed in nutritionally starved cells. Because the mutations occur after the onset of stress and in cells that are in non-replicative conditions, elucidating the underlying mechanisms contributes novel views to the process of evolution and apply to the formation of cancer in human cells and antibiotic resistance in microbial pathogens. Studies have shown that in Bacillus subtilis, the Mfd protein which is a transcription repair coupling factor is necessary for this phenomenon to occur. Here, we investigate …

Synthesis Of Chimeric Receptors Essential For Spore Germination, Christopher Yip, Christian Ross, Eduardo Robleto, Ernesto Abel-Santos

Undergraduate Research Opportunities Program (UROP)

Various species of bacteria have been reported to form an endospore, a metabolically dormant cell, during times of nutrient deficiencies and extreme stress. These said structures are outstandingly resistant to harsh chemicals, extreme temperatures, and can revert back to a metabolically active cell, through a process known as germination, when the necessary conditions are met. The rigid membrane of the endospore contains various germination (Ger) receptors which sense the external environment for necessary metabolites and germinants. Ger receptors are encoded by tricistronic operons that produce three distinct membrane proteins, the A, B, and C subunits. Although the function of the …

Dna Secondary Structures And Their Contribution To Mutagenesis In B. Subtilis Stationary Phase Cells, Carmen Vallin, Holly Martin, Christian Ross, Ronald Yasbin, Eduardo Robleto

Undergraduate Research Opportunities Program (UROP)

It is widely known and accepted that the cause of many mutations in cells are generated during the replication process of actively dividing cells, however more recent research has shown that mutations also arise in non growing conditions, a phenomenon known as stationary phase mutagenesis. Much of what is known come from studies in eukaryotic and bacterial models. It has been proposed that in non~growing cells, the process of transcription plays an important role in mutagenesis. We test the hypothesis that DNA secondary structures, formed during transcription, promote mutagenesis. The transcription-generated structures are speculated to be prone to mutations by …

A Spatial And Temporal Analysis Of Microbial Communities In Great Boiling Spring, Nevada, U.S.A., Jessica K. Guy, Joseph P. Peacock, Jeremy A. Dodsworth, Tanja Woyke, Tijana G. Del Rio, Brian P. Hedlund

Undergraduate Research Opportunities Program (UROP)

Great Boiling Spring (GBS) is a large, circumneutral, long residence time geothermal spring in the US Great Basin. Twelve samples were taken from four different sediment sites and the planktonic community in the bulk water of GBS on up to four different dates. Microbial community composition and diversity was assessed by using a barcoded, improved universal primer set targeting the V8 portion of the 16S rRNA gene and PCR. Over 200,000 products were sequenced using the Roche 454 GS FLX Titanium System. Sediment and planktonic microbial communities were distinct with very little overlap, regardless of the sampling location or temperature. …

Regulation Of The Shigella Flexneri Icsp Gene And H-Ns Dependent Repression, Rosa Ojeda, Amanda Wigley, Dustin Harrison, Helen Wing

Undergraduate Research Opportunities Program (UROP)

The gram negative bacterium Shigella flexneri is known to cause dysentery in humans and primates. In order to help prevent the spread of shigellosis, gene regulation must be understood. Studies show that the virulence genes in S .flexneri are thermo regulated. At 30°C histone-like nucleoid structuring protein (H-NS) represses transcription of virulence genes and at 37°C VirB derepresses virulence genes. One of the genes that contribute to the virulence of S. flexneri is icsP. My project focuses on the regulation of the S. flexneri icsP gene and has two main goals. The first is to identify the sequence of H-NS …

Interspecies Comparison Of Αii-Spectrin Abundance Between Chinook Salmon And Steelhead, Brielle D. Kemis, Ann L. Miracle, Katie A. Wagner, Christa M. Woodley

STAR Program Research Presentations

Salmonids, such as Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss), are a staple economic, recreational, tribal, and environmental resource, yet many populations are unsustainable. This study was part of a broad scale effort to monitor the impact of downstream migration obstacles on juvenile salmonid health and survival, which is an essential step towards increasing Smolt-to-Adult Return ratios (SARs). The objective of this study was to determine if juvenile Chinook salmon and steelhead exhibit differing quantities of alphaII-Spectrin Breakdown Products (SBDPs) over two consecutive spring migration periods, indicative of neurogenesis rate and/or biological response to head …

Growth And Hydrogen Production Of Rubrivivax Gelatinosus Cbs, Shannon A. Swanson, Karen Wawrousek

STAR Program Research Presentations

Rubrivivax gelatinosus CBS is a purple non-sulfur photosynthetic bacterium that has been found to produce substantial amounts of Hydrogen (H2) which could be used as a clean burning biofuel. CBS has been known to grow on a variety of carbon sources, but it is unknown as to which carbon sources it has the greatest potential to use, and this understanding could be helpful in engineering future strains of the bacteria. Hydrogen production in CBS occurs when carbon monoxide (CO) is present and is presumed to be under the control of the RcoM transcription factor. When CBS wild-type strains were grown …

Influence Of Environmental Conditions On Biofilm Formation Of Listeria Monocytogenes, Jing Li

All Theses

L. monocytogenes is a Gram-positive bacterium, ubiquitously distributed in the environment. It is the etiologic agent of listeriosis, a food-borne disease affecting humans and a variety of vertebrates. L. monocytogenes can form biofilm which is a multi-cellular layer of adherent bacteria surrounded by an extracellular polysaccharide matrix. Biofilm bacteria are extremely resistant to sanitizers and are difficult to be eradicated, therefore posing a big challenge to food processing industry and food service department.
In this work, we tested the biofilm formation in a number of L. monocytogenes serotypes under different environmental conditions, such as temperatures, pH and media (BHI, LB, …

Iron Limitation Of A Springtime Bacterial And Phytoplankton Community In The Ross Sea: Implications For Vitamin B12 Nutrition, Erin M. Bertrand, Mak A. Saito, Peter A. Lee, Robert B. Dunbar, Peter N. Sedwick, Giacomo R. Ditullio

OES Faculty Publications

The Ross Sea is home to some of the largest phytoplankton blooms in the Southern Ocean. Primary production in this system has previously been shown to be iron limited in the summer and periodically iron and vitamin B-12 colimited. In this study, we examined trace metal limitation of biological activity in the Ross Sea in the austral spring and considered possible implications for vitamin B-12 nutrition. Bottle incubation experiments demonstrated that iron limited phytoplankton growth in the austral spring while B-12, cobalt, and zinc did not. This is the first demonstration of iron limitation in a Phaeocystis antarctica-dominated, early …

Gata-Family Transcription Factors In Magnaporthe Oryzae, Cristian F. Quispe

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The filamentous fungus, Magnaporthe oryzae, responsible for blast rice disease, destroys around 10-30% of the rice crop annually. Infection begins when the specialized infection structure, the appressorium, generates enormous internal turgor pressure through the accumulation of glycerol. This turgor acts on a penetration peg emerging at the base of the cell, causing it to breach the leaf surface allowing its infection.

The enzyme trehalose-6- phosphate synthase (Tps1) is a central regulator of the transition from appressorium development to infectious hyphal growth. In the first chapter we show that initiation of rice blast disease requires a regulatory mechanism involving an …

Hiv-1 Circulating Recombinant Form In Nepal, Aniqa Shahid, Sameer M. Dixit, V. L. Gurbacharya, Dibesh Karmacharya, Syeda K. Ali

Department of Pathology and Laboratory Medicine

No abstract provided.

Effect Of The Infection With Porcine Reproductive And Respiratory Syndrome Virus On The Regulation Of Cytokines: Tumor Necrosis Factor-Alpha And Interleukin-10, Sakthivel Subramaniam

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Porcine reproductive and respiratory syndrome virus (PRRSV) causes late-term abortion in sows and pneumonia in growing piglets. PRRSV evades the host immune response by several mechanisms, including the modulation of cytokine secretions in infected pigs, which is the subject of this dissertation. Particularly, PRRSV reduces the secretion of the pro-inflammatory cytokine, tumor necrosis factor-α (TNF-α) but increases the secretion of the anti-inflammatory cytokine interleukin-10 (IL-10). The latter effect, however, is PRRSV strain-specific. In this dissertation, we have examined mechanisms by which PRRSV regulates TNF-α and IL-10 expressions. The pathogenic strain FL12, derived from a PRRSV infectious clone, consistently suppressed TNF-α …

Role Of Porcine Reproductive And Respiratory Syndrome Virus Non-Structural Protein 1 In Viral Replications And Pathogenesis, Lalit Kumar Beura

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Porcine reproductive and respiratory syndrome virus (PRRSV) is an infectious agent of significant concern to the global swine industry. PRRSV infection of pigs is initiated by a long viremia after which the virus enters in an extended persistent phase of 3-4 months that ultimately is resolved by the immune system. The delayed and weak host adaptive response is responsible for the protracted convalescence period. An initial sub-optimal innate immune response is postulated to be the reason behind such meager adaptive immune response. A major focus of the studies undertaken in this dissertation was to identify the viral non-structural proteins (nsps) …

Identification Of Host Proteins Required For Vesicular Stomatitis Virus Infection, Debasis Panda

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Viruses usurp host cell pathways for different stages of their infection. Understanding virus-host interaction will be invaluable to elucidate molecular mechanisms of virus infection and to identify drug targets. In order to identify such critical cellular genes in vesicular stomatitis virus (VSV, a model non-segmented negative strand RNA virus) infection, we developed a stable cell line constitutively expressing replication proteins of VSV. Attempts to establish a cell line replicating a sub-genomic replicon was not successful because of induction of interferon response by replication of viral genomic analog. Subsequently, we used siRNA technology and conducted a genome-wide siRNA screen in HeLa …

Upregulation Of Reactive Oxygen Species During The Retrovirus Life Cycle And Their Roles In A Mutant Of Moloney Murine Leukemia Virus, Ts1-Mediated Neurodegeneration, Soo Jin Kim

Dissertations and Theses (Open Access)

Viral invasion of the central nervous system (CNS) and development of neurological symptoms is a characteristic of many retroviruses. The mechanism by which retrovirus infection causes neurological dysfunction has yet to be fully elucidated. Given the complexity of the retrovirus-mediated neuropathogenesis, studies using small animal models are extremely valuable. Our laboratory has used a mutant moloney murine leukemia retrovirus, ts1-mediated neurodegneration. We hypothesize that astrocytes play an important role in ts1-induced neurodegeneration since they are retroviral reservoirs and supporting cells for neurons. It has been shown that ts1 is able to infect astrocytes in vivo and in …

Novel Mechanisms Of Antigen Processing That Enhance Bcg Vaccine Efficacy, Christopher R. Singh

Dissertations and Theses (Open Access)

Mycobacterium tuberculosis, the causative agent of tuberculosis, is the most lethal single infectious agent afflicting man today causing 2 million deaths per year. The World Health Organization recommends a vaccine as the best option to prevent this disease. The current vaccine, BCG, has a variable efficacy and does not protect adults. It is known that BCG vaccine becomes sequestered in special phagosome compartments of macrophages that do not fuse with lysosomes. Since lysosome fusion is necessary for peptide production and T cell priming leading to protective T_H1 immunity, we hypothesized that vaccine efficacy is reduced and occurs perhaps …

Mechanisms Of Adenovirus-Mediated Autophagy, Erin White

Dissertations and Theses (Open Access)

A patient diagnosed with a glioma, generally, has an average of 14 months year to live after implementation of conventional therapies such as surgery, chemotherapy, and radiation. Glioblastomas are highly lethal because of their aggressive nature and resistance to conventional therapies and apoptosis. Thus other avenues of cell death urgently need to be explored. Autophagy, which is also known as programmed cell death type II, has recently been identified as an alternative mechanism to kill apoptosis- resistant cancer cells. Traditionally, researchers have studied how cells undergo autophagy during viral infection as an immune response mechanism, but recently researchers have discovered …

Mechanisms Of Adenovirus-Mediated Autophagy, Erin White

Dissertations and Theses (Open Access)

A patient diagnosed with a glioma, generally, has an average of 14 months year to live after implementation of conventional therapies such as surgery, chemotherapy, and radiation. Glioblastomas are highly lethal because of their aggressive nature and resistance to conventional therapies and apoptosis. Thus other avenues of cell death urgently need to be explored. Autophagy, which is also known as programmed cell death type II, has recently been identified as an alternative mechanism to kill apoptosis- resistant cancer cells. Traditionally, researchers have studied how cells undergo autophagy during viral infection as an immune response mechanism, but recently researchers have discovered …

Eluding Antibiotic Resistance: Capitalizing On Antimicrobial Peptides Interaction With The Lipid Bilayer, Danielle M. Mcgrath

Dissertations and Theses (Open Access)

It is widely accepted that the emergence of drug-resistant pathogens is the result of the overuse and misuse of antibiotics. Infectious Disease Society of America, Center for Disease Control and World Health Organization continue to view, with concern, the lack of antibiotics in development, especially those against Gram-negative bacteria.

Antimicrobial peptides (AMPs) have been proposed as an alternative to antibiotics due to their selective activity against microbes and minor ability to induce resistance. For example, the Food and Drug Administration approved Daptomycin (DAP) in 2003 for treatment of severe skin infections caused by susceptible Gram-positive organisms. Currently, there are 12 …

Effect Of Goldenseal (Hydrastis Canadensis) On Bacterial Multi Drug Resistant Efflux Pumps, Jyothi Rangineni

All Dissertations

Multi-Drug Resistance (MDR) efflux pumps have been increasingly reported in Gram negative and Gram positive bacteria. These efflux mechanisms pump out a wide variety of structurally unrelated antimicrobials thus leading to a low susceptibility due to lowered intracellular concentrations. The activity of such antimicrobials can be restored by the inhibition of the multi drug efflux pumps. Several MDR pump inhibitors which inhibit the efflux mechanisms in bacteria have been identified. Reserpine and verapamil are two such inhibitors, showing considerable effect on the MDR pumps. But the concentrations required to achieve these effects are too high to be clinically relevant. Reserpine …

Regulation Of Bovine Herpesvirus 1 (Bhv-1) Productive Infection By Cellular Transcription Factors, Aspen M. Workman

School of Biological Sciences: Dissertations, Theses, and Student Research

Bovine herpesvirus 1 (BHV-1) is a significant viral pathogen of cattle responsible for a variety of disease conditions, including: conjunctivitis, pneumonia, genital disorders, abortions, and shipping fever, a serious upper respiratory tract infection. Following acute infection in mucosal epithelium, BHV-1 establishes a lifelong latent infection in sensory ganglionic neurons. During latency, transcription is restricted to the latency related (LR) gene. Elevated corticosteroid levels due to stress and/or immune suppression can initiate reactivation from latency, resulting in virus shedding and spread to susceptible cattle. Additionally, administration of dexamethasone (Dex), a synthetic corticosteroid, to calves latently infected with BHV-1 reproducibly leads to …

Kinetic Evaluation Of Colour, Texture, Polyphenols And Antioxidant Capacity Of Irish York Cabbage After Blanching Treatment, Amit Jaiswal, Shilpi Gupta, Nissreen Abu-Ghannam

Articles

In the present work, York cabbage was blanched between 80 to100°C with an increment of 5°C for up to 14 min and kinetics of the different physio-chemical properties were studied. Significant reductions in the texture, color, polyphenols (PPs) and antioxidant (AO) capacity were observed due to blanching. Total phenolic and flavonoid content retained ranged from 19.6-24.5 and 22.0-25.7%, respectively. Heavy losses in the AO capacity also occurred as a result of blanching, which was evident with a loss of 74.0-82.0% in activity as compared to raw York cabbage. Textural studies showed that blanching caused a significant reduction in firmness in …

Protection And Attachment Of Vibrio Cholerae Mediated By The Toxin-Coregulated Pilus In The Infant Mouse Model, Shelly J. Krebs, Ronald K. Taylor

Dartmouth Scholarship

Colonization of the human small intestine by Vibrio cholerae is an essential step in pathogenesis that requires the type IV toxin-coregulated pilus (TCP). To date, three functions of TCP have been characterized: it serves as the CTXΦ receptor, secretes the colonization factor TcpF, and functions in microcolony formation by mediating bacterium-bacterium interactions. Although type IV pili in other pathogenic bacteria have been characterized as playing a major role in attachment to epithelial cells, there are very few studies to suggest that TCP acts as an attachment factor. Taking this into consideration, we investigated the function of TCP in attachment to …

Expression And Function Of The Dna Damage Protein Umud Of Acinetobacter Baylyi, And Its Predicted Cleavage And Nucleophilic Activator Residue Mutants In Escherichia Coli, Sabal Adhikari

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science & Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Sabal Adhikari on July 28, 2011.

Applied And Mechanistic Studies Of Microbial 17beta-Estradiol Degradation, Zhongtian Li

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The presence of natural estrogens, a class of endocrine disrupting compounds, in water has caused increasing concerns over their adverse impacts on the health of aquatic eco-systems and human beings. In this study, adsorption characteristics of two natural estrogens, 17β-estradiol (E2) and estrone (E1), on granular activated carbon (GAC) were investigated in isotherm tests and in a GAC column. The GAC column was then converted to a biologically active carbon (BAC) column and the removal efficiency of E2 and its primary biodegradation intermediate E1 were monitored. During BAC operation, the impacts of various reactor operation parameters, such as the carbon …

Combating Bioterrorism: Purification And Structural Analysis Of The E3 Proteins Of The Venezuelan Equine Encephalitis Virus And The Chikungunya Virus, Tyshia Gwin

The Journal of Purdue Undergraduate Research

Outbreaks of the Venezuelan Equine Encephalitis Virus (VEEV) and the Chikungunya Virus (CHIKV) continue to emerge in Central and South America, Africa, and Asia, but there are currently no vaccines or anti-virals for these viruses. Given their ease of transmission, debilitating symptoms, and genetic alterability, VEEV and CHIKV have great potential for development into biological weapons. Therefore, there is an urgent need to determine possible methods of treatment or prevention. One possibility of prevention lies in determining the structure and biological function of the E3 protein that plays a key role in the infectivity of the viruses. In this research, …

Comparison Of Adenoviruses As Oncolytics And Cancer Vaccines In An Immunocompetent B Cell Lymphoma Model, Eric A. Weaver, Christopher Y. Chen, Shannon M. May, Mary E. Barry, Michael A. Barry

Nebraska Center for Virology: Faculty Publications

We have screened human adenoviruses (Ads) for oncolytic activity against a variety of mouse and hamster cell lines and have found a number that are susceptible to a variety of Ad serotypes. A20 lymphoma is derived from BALB/c mice and is susceptible to infection and killing by a variety of human Ads. A20 is also a suitable cancer vaccine model, because these cells express a unique immunoglobulin variable region that can be targeted by vaccination. To compare Ads as cancer vaccines versus Ads as oncolytics, A20 tumors were initiated in immunocompetent BALB/c mice. Mice immunized with first-generation Ad5 expressing the …