Microbiology Commons^™

Soil Microbial Community Response To Climate Change: Results From A Temperate Kentucky Pasture, Lindsey C. Slaughter

Theses and Dissertations--Plant and Soil Sciences

Climate change is likely to alter plant species composition and interactions between plants and soil microbes that together dictate the quantity and quality of forage produced in pastures, the base of animal production in central Kentucky. This study assessed the seasonal dynamics of soil microbes and their response to increased temperature (+3^oC) and growing season precipitation (+30% of the mean annual). Total soil microbial biomass, community composition, enzyme activities, potential carbon mineralization, and catabolic responses to selected substrates were measured seasonally in the different climate treatments. In this system, seasonal variability was a dominant driving factor for all …

Investigation Of The Membrane Interactions Of Mycobacterium Tuberculosis Secreted Factors Esat-6 And Cfp-10, Joaquin A. De Leon

Open Access Theses & Dissertations

Mycobacterium tuberculosis is the causative agent of the infectious disease tuberculosis, infecting about one-third of human race. Infections are not vast in the United States when compared to many other countries, yet many cases seen in the United States are of those who have immigrated to the United States. The Hispanic/Latino population in the United States contributes to a large fraction of those infected with tuberculosis in the United States. During this study we purified recombinant Mycobacterium tuberculosis secreted factors ESAT-6 and CFP-10 from Escherichia coli. Here we have introduced a method in which we can refold and purify …

Examining Autoimmune Sequelae During Cancer Immunotherapy In A Combined Autoimmune Thyroiditis And Tumor Mouse Model, Suresh Kari

Wayne State University Dissertations

Some clinical trials of immunotherapeutic agents against cancers have resulted in the development of autoimmune sequelae, including autoimmune thyroiditis. It has been suggested that the immunotherapy resulted in an alteration in the immunoregulatory mechanism(s). Using experimental autoimmune thyroiditis (EAT), a mouse model of Hashimoto's thyroiditis (HT), the importance of regulatory T cells (Tregs) has been well established; inhibition of Tregs leads to enhanced thyroiditis with repeated doses of mouse thyroglobulin (mTg) without adjuvant. To simulate cancer patients, we developed a combined EAT and tumor model in our EAT-susceptible mice (CBA/J). In first establishing the tumor model, we found Treg depletion …

Membrane-Bound Immunomodulators As Adjuvants In A Cell Culture-Based Avian Influenza Vaccine, David Daniel Fischer

Wayne State University Dissertations

Inactivated viral vaccines often generate suboptimal immune responses. Adjuvants are incorporated into vaccines to increase their immunogenicity, however currently available adjuvants have shortcomings which have limited their use in human and veterinary medicine. This necessitates the development of new adjuvants and delivery systems. Cytokines have been extensively tested as adjuvants in vaccines but challenges such as diffusion from antigen, short half-lives and production costs have been encountered. To address this, we developed a technology that efficiently produces inactivated, whole-virus influenza vaccine bearing membrane-bound cytokines. Tethering the cytokine to the antigen of interest keeps the immunomodulator in close contact with the …

Stability Of Antibiotic Resistance Patterns In Agricultural Pastures: Lessons From Kentucky, Usa, Sloane Ritchey, Siva Gandhapudi, Mark Coyne

Plant and Soil Sciences Faculty Publications

No abstract provided.

Diversity And Dynamics Of Bacterial Communities In Early Life Stages Of The Caribbean Coral Porites Astreoides, Koty H. Sharp, Dan Distel, Valerie J. Paul

Arts & Sciences Faculty Publications

In this study, we examine microbial communities of early developmental stages of the coral Porites astreoides by sequence analysis of cloned 16S rRNA genes, terminal restriction fragment length polymorphism (TRFLP), and fluorescence in situ hybridization (FISH) imaging. Bacteria are associated with the ectoderm layer in newly released planula larvae, in 4-day-old planulae, and on the newly forming mesenteries surrounding developing septa in juvenile polyps after settlement. Roseobacter clade-associated (RCA) bacteria and Marinobacter sp. are consistently detected in specimens of P. astreoides spanning three early developmental stages, two locations in the Caribbean and 3 years of collection. Multi-response permutation procedures analysis …

Establishment Of A Quiescent Infection Of Hsv-1 In L929 Fibroblasts Using A Mitotic Inhibitor And Ifn-Γ, Neelam V. Shinde

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The goal for this study was to determine if a quiescent infection of HSV-1 could be induced in murine fibroblasts L929 by treating them with the anti-mitotic agent 5-fluoro 2'deoxy uridine (FUDR) alone and with interferon-γ. Since neurons are post-mitotic and exhibit a lower metabolic rate than other cells, fibroblasts were treated with FUDR to induce a post-mitotic state. The cell cycle arrest of fibroblasts would decrease the thymidylate metabolism and impair HSV-1 replication. An evaluation of cytopathic effects of FUDR was used to determine the optimal concentration which arrests cell growth and inhibits viral replication. Image J program developed …

Q-Ve-Oph, A Control Caspase Inhibitor For Analyzing Neuronal Death, Rebecca L. Bricker

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Sarin is a neurotoxin that has been used in terrorist attacks in Japan and is a potential bioterrorist weapon. It induces seizures by affecting the regulation of neurotransmitters in the brain. Seizures are directly correlated to neuronal damage. Two types of neuronal damage that can occur are apoptosis and necrosis. One of the main regions of the brain where neuronal death occurs is the hippocampus, which is involved in memory. Victims showed chronic decline of memory loss 3 and 7 years after the Tokyo's terrorist attack incident. There are treatments available that can break down sarin or can block the …

The Effects Of Enteropathogenic And Commensal Escherichia Coli On Tight Junction Permeability, Hilary Kaye Allen

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The intestinal mucosa maintains a barrier between materials from the external environment and the internal environment of the host. Disruption of the gut wall integrity is involved in the development of various intestinal diseases, such as Irritable Bowel Syndrome (IBS) and Crohn's disease. The intestinal mucosa is lined with epithelial cells that are connected by tight junctions, the intercellular junctions that form a selectively permeable barrier between paracellular pathways. Enteric pathogens, such as enteropathogenic Escherichia coli (EPEC), can disrupt the tight junctions of epithelial cells by altering the cellular cytoskeleton or by directly affecting tight junction proteins. Commensal Escherichia coli …

Mhc Class I Expression In Murine Fibroblast And Keratinocyte Cell Lines During The First Twenty-Four Hours Of Infection With Herpes Simplex Virus-1 (Hsv-1), Prasanthi Kumchala

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The hypothesis of this study is: HSV-1 infection of murine fibroblasts and keratinocytes inhibits expression of MHC class I molecules during first 24 hours of infection. IFN-γ pretreatment of fibroblasts protected the cells from virus-induced inhibition of MHC class I expression, but did not protect keratinocytes. Herpesviruses are known for their ability to establish persistent infections. Herpesviruses exert many different ways to suppress host defense mechanisms. One such way is by down regulating expression of the major histocompatibility complex I (MHC I) molecules in infected cells. Epidermal cells such as keratinocytes are the major sites for herpes simplex virus type …

The Effects Of Hsv-1 Challenge On Polarized Murine Macrophages: An In Vitro Model Using The J774a.1 Murine Macrophage Cell Line, Adam Craig Reichard

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In our current study we examined the effects of HSV-1 challenge on J774A.1 macrophages polarized to either a proinflammatory (M1) or anti-inflammatory (M2) phenotype. Polarized J774A.1 macrophages were characterized using CD14-CD86 and SOCS1-SOCS3 expression levels. SOCS proteins are a family of proteins that are capable of inhibiting cytokine-signaling pathways. HSV-1 up regulates expression of SOCS1 protein levels in infected cells, inhibiting the ability of infected cells to produce proinflammatory products (Nowoslawski Akhtar and Benveniste, 2011). This study shows that signals within the microenvironment play a greater role in macrophage polarization, and SOCS1-SOCS3 expression levels, than does HSV-1 challenge. M1 macrophages …

Suppressor Of Cytokine Signaling (Socs) 1 & 3 Expression In Hsv-1- Infected And Interferon-Γ-Treated Neuro-2a Cells, Melinda Jones

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This study examined the effects of HSV-1 infection and IFN-γ treatment on Neuro-2A cells. HSV-1 induces expression of SOCS1 and SOCS3 in infected cells, inhibiting the ability of these cells to produce the pro inflammatory, antiviral cytokine IFN-γ (Nowoslawski and Benveniste, 2011). SOCS1 and SOCS3 levels were determined in IFN-γ-treated cells, virus-infected cells, and cells that were both IFN-γ-treated and virus-infected. Results were compared with untreated, uninfected control cells. Flow cytometry data analysis showed a slight decrease in SOCS1 and SOCS3 protein levels in cells treated with IFN-γ for 6 hours compared to control cells. A significant decrease in SOCS1 …

The Construction Of A Plasmid For Detecting The Pathway Of Arginine Metabolism In Human Macrophages: A Real-Time Assessment Of Macrophage Polarity, Benjamin A. Holmes

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Macrophages are "first responders", innate immune system cells which quickly arrive to a site of infection and injury, consuming cell debris and foreign matter and recruiting other immune system cells to the area. While historically they have been thought to react uniformly to all challenges, the discovery of toll-like receptors has shown that macrophages actually work closely with the adaptive immune system in fine-tuning the immune response. Furthermore, it has recently been discovered that macrophages can become polarized to one of two subtypes-M1 or M2.

M1 macrophages are efficient producers of reactive oxygen species, nitrogen intermediates, and inflammatory cytokines. They …

Efficient And Robust Rna-Seq Process For Cultured Bacteria And Complex Community Transcriptomes, Georgia Giannoukos, Dawn M. Ciulla, Katherine Huang, Brian J. Haas, Jacques Izard, Joshua Z. Levin, Jonathan Livny, Ashlee M. Earl, Dirk Gevers, Doyle V. Ward, Chad Nusbaum, Bruce W. Birren, Andreas Gnirke

Department of Food Science and Technology: Faculty Publications

We have developed a process for transcriptome analysis of bacterial communities that accommodates both intact and fragmented starting RNA and combines efficient rRNA removal with strand-specific RNA-seq. We applied this approach to an RNA mixture derived from three diverse cultured bacterial species and to RNA isolated from clinical stool samples. The resulting expression profiles were highly reproducible, enriched up to 40-fold for non-rRNA transcripts, and correlated well with profiles representing undepleted total RNA.

Interleukin-6 Control Of Early Theiler’S Murine Encephalomyelitis Virus Replication In Macrophages Occurs In Conjunction With Stat1 Activation And Nitric Oxide Production., Tyler C. Moore, Katherine L. Bush, Deborah M. Brown, Thomas M. Petro

Nebraska Center for Virology: Faculty Publications

During Theiler’s virus (TMEV) infection of macrophages it is thought that high IL-6 levels contribute to demyelinating disease found in chronically infected SJL/J mice but absent in B10.S mice capable of clearing the infection. Therefore, IL-6 expression was measured in TMEV-susceptible SJL/J and TMEV-resistant B10.S macrophages during their infection with TMEV DA strain or responses to LPS or poly I:C. Unexpectedly, IL-6 production was greater in B10.S macrophages than SJL/J macrophages during the first 24 h after stimulation with TMEV, LPS or poly I:C. Further experiments showed that in B10.S, SJL/J, and RAW264.7 macrophage cells, IL-6 expression was dependent on …

Chloroviruses: Not Your Everyday Plant Virus, James L. Van Etten, David D. Dunigan

Nebraska Center for Virology: Faculty Publications

Viruses infecting higher plants are among the smallest viruses known and typically have four to ten protein-encoding genes. By contrast, many viruses that infect algae (classified in the virus family Phycodnaviridae) are among the largest viruses found to date and have up to 600 protein- encoding genes. This brief review focuses on one group of plaque-forming phycodnaviruses that infect unicellular chlorella-like green algae. The prototype chlorovirus PBCV-1 has more than 400 protein-encoding genes and 11 tRNA genes. About 40% of the PBCV-1 encoded proteins resemble proteins of known function including many that are completely unexpected for a virus. In many …

Molecular Genetic And Biochemical Characterization Of The Vaccinia Virus I3 Protein, The Replicative Single-Stranded Dna Binding Protein, Matthew D. Greseth, Kathleen A. Boyle, Matthew S. Bluma, Bethany Unger, Matthew S. Wiebe, Jamaria A. Soares-Martins, Nadi T. Wickramasekera, James Wahlberg, Paula Traktman

Nebraska Center for Virology: Faculty Publications

Vaccinia virus, the prototypic poxvirus, efficiently and faithfully replicates its approximately 200-kb DNA genome within the cytoplasm of infected cells. This intracellular localization dictates that vaccinia virus encodes most, if not all, of its own DNA replication machinery. Included in the repertoire of viral replication proteins is the I3 protein, which binds to single-stranded DNA (ssDNA) with great specificity and stability and has been presumed to be the replicative ssDNA binding protein (SSB). We substantiate here that I3 colocalizes with bromodeoxyuridine (BrdU)-labeled nascent viral genomes and that these genomes accumulate in cytoplasmic factories that are delimited by membranes derived from …

Lineage-Specific Differences Between Human And Simian Immunodeficiency Virus Regulation Of Gp120 Trimer Association And Cd4 Binding, Andrés Finzi, Beatriz Pacheco, Shi-Hua Xiang, Marie Pancera, Alon Herschhorn, Liping Wang, Xing Zeng, Anik Desormeaux, Peter D. Kwong, Joseph Sodroski

Nebraska Center for Virology: Faculty Publications

Metastable conformations of the gp120 and gp41 envelope glycoproteins of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) must be maintained in the unliganded state of the envelope glycoprotein trimer. Binding of gp120 to the primary receptor, CD4, triggers the transition to an open conformation of the trimer, promoting interaction with the CCR5 chemokine receptor and ultimately leading to gp41-mediated virus-cell membrane fusion and entry. Topological layers in the gp120 inner domain contribute to gp120-trimer association in the unliganded state and to CD4 binding. Here we describe similarities and differences between HIV-1 and SIVmac gp120. In both …

Subunit Organization Of The Membrane-Bound Hiv-1 Envelope Glycoprotein Trimer, Youdong Mao, Liping Wang, Christopher Gu, Alon Herschhorn, Shi-Hua Xiang, Hillel Haim, Xinzhen Yang, Joseph Sodroski

Nebraska Center for Virology: Faculty Publications

The trimeric human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) spike is a molecular machine that mediates virus entry into host cells and is the sole target for virus-neutralizing antibodies. The mature Env spike results from cleavage of a trimeric gp160 precursor into three gp120 and three gp41 subunits. Here we describe an ~11-Å cryo-EM structure of the trimeric HIV-1 Env precursor in its unliganded state. The three gp120 and three gp41 subunits form a cage-like structure with an interior void surrounding the trimer axis. Interprotomer contacts are limited to the gp41 transmembrane region, the torus-like gp41 ectodomain, and …

Comparative Analysis Of The Fusion Efficiency Elicited By The Envelope Glycoprotein V1–V5 Regions Derived From Human Immunodeficiency Virus Type 1 Transmitted Perinatally, Hongyan Guo, Levon Abrahamyan, Chang Liu, Mackenzie Waltke, Yunqi Geng, Qimin Chen, Charles Wood, Xiaohong Kong

Nebraska Center for Virology: Faculty Publications

Understanding the properties of viruses preferentially establishing infection during perinatal transmission of human immunodeficiency virus type 1 (HIV-1) is critical for the development of effective measures to prevent transmission. A previous study demonstrated that the newly transmitted viruses (in infants) of chronically infected mother–infant pairs (MIPs) were fitter in terms of growth, which was imparted by their envelope (Env) glycoprotein V1–V5 regions, than those in the corresponding chronically infected mothers. In order to investigate whether the higher fitness of transmitted viruses was conferred by their higher entry efficiency directed by the V1–V5 regions during perinatal transmission, the fusogenicity of Env …