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Medical Microbiology

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2006

Articles 1 - 10 of 10

Full-Text Articles in Life Sciences

The Role Of Mapks In B Cell Receptor-Induced Down-Regulation Of Egr-1 In Immature B Lymphoma Cells, Jiyuan Ke, Murali Gururajan, Anupam Kumar, Alan Simmons, Lilia Turcios, Ralph Lakshman Chelvarajan, David M. Cohen, David L. Wiest, John G. Monroe, Subbarao Bondada Oct 2006

The Role Of Mapks In B Cell Receptor-Induced Down-Regulation Of Egr-1 In Immature B Lymphoma Cells, Jiyuan Ke, Murali Gururajan, Anupam Kumar, Alan Simmons, Lilia Turcios, Ralph Lakshman Chelvarajan, David M. Cohen, David L. Wiest, John G. Monroe, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Cross-linking of the B cell receptor (BCR) on the immature B lymphoma cell line BKS-2 induces growth inhibition and apoptosis accompanied by rapid down-regulation of the immediate-early gene egr-1. In these lymphoma cells, egr-1 is expressed constitutively and has a prosurvival role, as Egr-1-specific antisense oligonucleotides or expression of a dominant-negative inhibitor of Egr-1 also prevented the growth of BKS-2 cells. Moreover, enhancement of Egr-1 protein with phorbol 12-myristate 13-acetate or an egr-1 expression vector rescued BKS-2 cells from BCR signal-induced growth inhibition. Nuclear run-on and mRNA stability assays indicated that BCR-derived signals act at the transcriptional level to …

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Cd80 And Cd86 Control Antiviral Cd8+ T-Cell Function And Immune Surveillance Of Murine Gammaherpesvirus 68, Shinichiro Fuse, Joshua J. Obar, Sarah Bellfy, Erica K. Leung, Weijun Zhang, Edward J. Usherwood Sep 2006

Cd80 And Cd86 Control Antiviral Cd8+ T-Cell Function And Immune Surveillance Of Murine Gammaherpesvirus 68, Shinichiro Fuse, Joshua J. Obar, Sarah Bellfy, Erica K. Leung, Weijun Zhang, Edward J. Usherwood

Dartmouth Scholarship

The interactions between CD80 and CD86 on antigen-presenting cells and CD28 on T cells serve as an important costimulatory signal in the activation of T cells. Although the simplistic two-signal hypothesis has been challenged in recent years by the identification of different costimulators, this classical pathway has been shown to significantly impact antiviral humoral and cellular immune responses. How the CD80/CD86-CD28 pathway affects the control of chronic or latent infections has been less well characterized. In this study, we investigated its role in antiviral immune responses against murine gammaherpesvirus 68 (MHV-68) and immune surveillance using CD80/CD86−/− mice. In the …

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Gammaherpesvirus Persistence Alters Key Cd8 T-Cell Memory Characteristics And Enhances Antiviral Protection, Joshua J. Obar, Shinichiro Fuse, Erica K. Leung, Sarah C. Bellfy, Edward J. Usherwood Sep 2006

Gammaherpesvirus Persistence Alters Key Cd8 T-Cell Memory Characteristics And Enhances Antiviral Protection, Joshua J. Obar, Shinichiro Fuse, Erica K. Leung, Sarah C. Bellfy, Edward J. Usherwood

Dartmouth Scholarship

In herpesvirus infections, the virus persists for life but is contained through T-cell-mediated immune surveillance. How this immune surveillance operates is poorly understood. Recent studies of other persistent infections have indicated that virus persistence is associated with functional deficits in the CD8(+) T-cell response. To test whether this is the case in a herpesvirus infection, we used a mutant murine gammaherpesvirus that is defective in its ability to persist in the host. By comparing the immune response to this virus with a revertant virus that can persist, we were able to dissect the changes in the antiviral CD8(+) T-cell response …

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Salicylic Acid Activates Sigma Factor B By Rsbu-Dependent And -Independent Mechanisms, Marco Palma, Arnold Bayer, Leon I. Kupferwasser, Tammy Joska, Michael R. Yeaman, Ambrose Cheung Aug 2006

Salicylic Acid Activates Sigma Factor B By Rsbu-Dependent And -Independent Mechanisms, Marco Palma, Arnold Bayer, Leon I. Kupferwasser, Tammy Joska, Michael R. Yeaman, Ambrose Cheung

Dartmouth Scholarship

Salicylic acid (SAL) may impact Staphylococcus aureus virulence by activating the sigB operon (rsbU-V-W-sigB), thus leading to reductions in alpha-toxin production and decreased fibronectin binding (L. I. Kupferwasser et al., J. Clin. Investig. 112:222-233, 2003). As these prior studies were performed in strain RN6390 (an rsbU mutant) and its rsbU-repaired variant, SH1000, the current investigation was designed to determine if the SAL effect occurs via rsbU- and/or rsbV-dependent pathways in an rsbU-intact S. aureus strain (FDA486). We thus quantified the transcription from two sigB-dependent promoters (asp23 and sarA P3) in FDA486 in response to SAL exposure in vitro, using isogenic …

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The Role Of Cd4 T Cells In The Pathogenesis Of Murine Aids, Wen Li, William R. Green Jun 2006

The Role Of Cd4 T Cells In The Pathogenesis Of Murine Aids, Wen Li, William R. Green

Dartmouth Scholarship

LP-BM5, a retroviral isolate, induces a disease featuring retrovirus-induced immunodeficiency, designated murine AIDS (MAIDS). Many of the features of the LP-BM5-induced syndrome are shared with human immunodeficiency virus-induced disease. For example, CD4 T cells are critical to the development of MAIDS. In vivo depletion of CD4 T cells before LP-BM5 infection rendered genetically susceptible B6 mice MAIDS resistant. Similarly, MAIDS did not develop in B6.nude mice. However, if reconstituted with CD4 T cells, B6.nude mice develop full-blown MAIDS. Our laboratory has shown that the interaction of B and CD4 T cells that is central to MAIDS pathogenesis requires ligation of …

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Probability Of Real -Time Detection Vs Probability Of Infection For Aerosolized Biowarfare Agents: A Model Study., Alexander G. Sabelnikov, Vladimir Zhukov, C Ruth Kempf May 2006

Probability Of Real -Time Detection Vs Probability Of Infection For Aerosolized Biowarfare Agents: A Model Study., Alexander G. Sabelnikov, Vladimir Zhukov, C Ruth Kempf

Alexander G Sabelnikov

No abstract provided.

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H2-M3-Restricted Cd8+ T Cells Are Not Required For Mhc Class Ib-Restricted Immunity Against Listeria Monocytogenes, Sarah E. F. D'Orazio, Christine A. Shaw, Michael N. Starnbach Feb 2006

H2-M3-Restricted Cd8+ T Cells Are Not Required For Mhc Class Ib-Restricted Immunity Against Listeria Monocytogenes, Sarah E. F. D'Orazio, Christine A. Shaw, Michael N. Starnbach

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Studies using major histocompatibility complex (MHC)-Ia–deficient mice have shown that MHC-Ib–restricted CD8+ T cells can clear infections caused by intracellular pathogens such as Listeria monocytogenes. M3-restricted CD8+ T cells, which recognize short hydrophobic N-formylated peptides, appear to comprise a substantial portion of the MHC-Ib–restricted T cell response in the mouse model of L. monocytogenes infection. In this study, we isolated formyltransferase (fmt) mutant strains of L. monocytogenes that lacked the ability to add formyl groups to nascent polypeptides. These fmt mutant Listeria strains did not produce antigens that could be recognized by M3-restricted T …

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Keeping Their Options Open: Acute Versus Persistent Infections, S. Furukawa, S. L. Kuchma, G. A. O'Toole Feb 2006

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

Dartmouth Scholarship

No abstract provided.

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Tannerella Forsythia, A Periodontal Pathogen Entering The Genomic Era, Anne C.R. Tanner, Jacques Izard Jan 2006

Tannerella Forsythia, A Periodontal Pathogen Entering The Genomic Era, Anne C.R. Tanner, Jacques Izard

Department of Food Science and Technology: Faculty Publications

Several questions need to be addressed to evaluate whether Tannerella forsythia is to be considered a periodontal pathogen. T. forsythia has been detected in periodontal health and disease, so could it be a pathogen? The species was not detected in many studies despite finding other putative pathogens, so could it be important in pathogenicity? The challenges of working with T. forsythia include its fastidious and anaerobic growth requirements for cultural detection. Thus, studies associating T. forsythia with periodontal and other oral infections have used noncultural approaches (immunoassays and DNA-based assays) in addition to cultural approaches. We feel the timing of …

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Transposon Disruption Of The Complex I Nadh Oxidoreductase Gene (Snod) In Staphylococcus Aureus Is Associated With Reduced Susceptibility To The Microbicidal Activity Of Thrombin-Induced Platelet Microbicidal Protein 1, Arnold S. Bayer, Peter Mcnamara, Michael R. Yeaman, Natalie Lucindo, Tiffanny Jones, Ambrose L. Cheung Jan 2006

Transposon Disruption Of The Complex I Nadh Oxidoreductase Gene (Snod) In Staphylococcus Aureus Is Associated With Reduced Susceptibility To The Microbicidal Activity Of Thrombin-Induced Platelet Microbicidal Protein 1, Arnold S. Bayer, Peter Mcnamara, Michael R. Yeaman, Natalie Lucindo, Tiffanny Jones, Ambrose L. Cheung

Dartmouth Scholarship

The cationic molecule thrombin-induced platelet microbicidal protein 1 (tPMP-1) exerts potent activity against Staphylococcus aureus. We previously reported that a Tn551 S. aureus transposon mutant, ISP479R, and two bacteriophage back-transductants, TxA and TxB, exhibit reduced in vitro susceptibility to tPMP-1 (tPMP-1(r)) compared to the parental strain, ISP479C (V. Dhawan, M. R. Yeaman, A. L. Cheung, E. Kim, P. M. Sullam, and A. S. Bayer, Infect. Immun. 65:3293-3299, 1997). In the current study, the genetic basis for tPMP-1(r) in these mutants was identified. GenBank homology searches using sequence corresponding to chromosomal DNA flanking Tn551 mutant strains showed that the fourth gene …

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