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Full-Text Articles in Medicine and Health Sciences
Iron-Dependent Gene Expression In Actinomyces Oris, Matthew P. Mulé, David Giacalone, Kayla Lawlor, Alexa Golden, Caroline Cook, Thomas Lott, Elizabeth Aksten, George A. O'Toole, Lori J. Bergeron
Iron-Dependent Gene Expression In Actinomyces Oris, Matthew P. Mulé, David Giacalone, Kayla Lawlor, Alexa Golden, Caroline Cook, Thomas Lott, Elizabeth Aksten, George A. O'Toole, Lori J. Bergeron
Dartmouth Scholarship
Actinomyces oris is a Gram-positive bacterium that has been associated with healthy and diseased sites in the human oral cavity. Most pathogenic bacteria require iron to survive, and in order to acquire iron in the relatively iron-scarce oral cavity A. oris has been shown to produce iron-binding molecules known as siderophores. The genes encoding these siderophores and transporters are thought to be regulated by the amount of iron in the growth medium and by the metal-dependent repressor, AmdR, which we showed previously binds to the promoter of proposed iron-regulated genes.
Coculture Of Staphylococcus Aureus With Pseudomonas Aeruginosa Drives S. Aureus Towards Fermentative Metabolism And Reduced Viability In A Cystic Fibrosis Model, Laura M. Filkins, Jyoti A. Graber, Daniel G. Olson, Emily L. Dolben, Lee Lynd, Sabin Bhuju, George A. O'Toole
Coculture Of Staphylococcus Aureus With Pseudomonas Aeruginosa Drives S. Aureus Towards Fermentative Metabolism And Reduced Viability In A Cystic Fibrosis Model, Laura M. Filkins, Jyoti A. Graber, Daniel G. Olson, Emily L. Dolben, Lee Lynd, Sabin Bhuju, George A. O'Toole
Dartmouth Scholarship
The airways of patients with cystic fibrosis are colonized with diverse bacterial communities that change dynamically during pediatric years and early adulthood. Staphylococcus aureus is the most prevalent pathogen during early childhood, but during late teens and early adulthood, a shift in microbial composition occurs leading to Pseudomonas aeruginosa community predominance in ∼50% of adults. We developed a robust dual-bacterial in vitro coculture system of P. aeruginosa and S. aureus on monolayers of human bronchial epithelial cells homozygous for the ΔF508 cystic fibrosis transmembrane conductance regulator (CFTR) mutation to better model the mechanisms of this interaction. We show that P. …
The Toxoplasma Gondii Cyst Wall Protein Cst1 Is Critical For Cyst Wall Integrity And Promotes Bradyzoite Persistence, Tadakimi Tomita, David J. Bzik, Yan Fen Ma, Barbara A. Fox
The Toxoplasma Gondii Cyst Wall Protein Cst1 Is Critical For Cyst Wall Integrity And Promotes Bradyzoite Persistence, Tadakimi Tomita, David J. Bzik, Yan Fen Ma, Barbara A. Fox
Dartmouth Scholarship
Toxoplasma gondii infects up to one third of the world's population. A key to the success of T. gondii as a parasite is its ability to persist for the life of its host as bradyzoites within tissue cysts. The glycosylated cyst wall is the key structural feature that facilitates persistence and oral transmission of this parasite. Because most of the antibodies and reagents that recognize the cyst wall recognize carbohydrates, identification of the components of the cyst wall has been technically challenging. We have identified CST1 (TGME49_064660) as a 250 kDa SRS (SAG1 related sequence) domain protein with a large …
Myeloid-Derived Suppressor Cells In Murine Retrovirus-Induced Aids Inhibit T- And B-Cell Responses In Vitro That Are Used To Define The Immunodeficiency, Kathy A. Green, W. James Cook, William R. Green
Myeloid-Derived Suppressor Cells In Murine Retrovirus-Induced Aids Inhibit T- And B-Cell Responses In Vitro That Are Used To Define The Immunodeficiency, Kathy A. Green, W. James Cook, William R. Green
Dartmouth Scholarship
Myeloid-derived suppressor cells (MDSCs) have been characterized in several disease settings, especially in many tumor systems. Compared to their involvement in tumor microenvironments, however, MDSCs have been less well studied in their responses to infectious disease processes, in particular to retroviruses that induce immunodeficiency. Here, we demonstrate for the first time the development of a highly immunosuppressive MDSC population that is dependent on infection by the LP-BM5 retrovirus, which causes murine acquired immunodeficiency. These MDSCs express a cell surface marker signature (CD11b Gr-1 Ly6C ) characteristic of monocyte-type MDSCs. Such MDSCs profoundly inhibit immune responsiveness by a cell dose- and …
Alpha-Defensins 1-3 Release By Dendritic Cells Is Reduced By Estrogen, Maria M. Escribese, Marta Rodríguez-García, Rhoda Sperling, Stephanie M. Engel
Alpha-Defensins 1-3 Release By Dendritic Cells Is Reduced By Estrogen, Maria M. Escribese, Marta Rodríguez-García, Rhoda Sperling, Stephanie M. Engel
Dartmouth Scholarship
During pregnancy the immune system of the mother must protect any activation that may negatively affect the fetus. Changes in susceptibility to infection as well as resolution of some autoimmune disorders represent empirical evidence for pregnancy related alterations in immunity. Sex hormones reach extremely high levels during pregnancy and have been shown to have direct effects on many immune functions including the antiviral response of dendritic cells. Among the immunologically active proteins secreted by monocyte derived DCs (MDDC) are the alpha-defensins 1-3. This family of cationic antimicrobial peptides has a broad spectrum of microbicidal activity and has also been shown …
Cpg Hypomethylation In A Large Domain Encompassing The Embryonic Β-Like Globin Genes In Primitive Erythrocytes, Mei Hsu, Rodwell R. Mabaera, Christopher H. Lowrey, David I. K. Martin, Steven Fiering
Cpg Hypomethylation In A Large Domain Encompassing The Embryonic Β-Like Globin Genes In Primitive Erythrocytes, Mei Hsu, Rodwell R. Mabaera, Christopher H. Lowrey, David I. K. Martin, Steven Fiering
Dartmouth Scholarship
There is little evidence addressing the role of CpG methylation in transcriptional control of genes that do not contain CpG islands. This is reflected in the ongoing debate about whether CpG methylation merely suppresses retroelements or if it also plays a role in developmental and tissue-specific gene regulation. The genes of the β-globin locus are an important model of mammalian developmental gene regulation and do not contain CpG islands. We have analyzed the methylation status of regions in the murine β-like globin locus in uncultured primitive and definitive erythroblasts and other cultured primary and transformed cell types. A large (∼20-kb) …
Effects Of Estradiol On Lipopolysaccharide And Pam3cys Stimulation Of Ccl20/Macrophage Inflammatory Protein 3 Alpha And Tumor Necrosis Factor Alpha Production By Uterine Epithelial Cells In Culture, Mardi A. Crane-Godreau, Charles R. Wira
Effects Of Estradiol On Lipopolysaccharide And Pam3cys Stimulation Of Ccl20/Macrophage Inflammatory Protein 3 Alpha And Tumor Necrosis Factor Alpha Production By Uterine Epithelial Cells In Culture, Mardi A. Crane-Godreau, Charles R. Wira
Dartmouth Scholarship
We have previously demonstrated that rat uterine epithelial cells (UEC) produce CCL20/macrophage inflammatory protein 3 alpha (MIP3alpha) and tumor necrosis factor alpha (TNF-alpha) in response to live and heat-killed Escherichia coli and to the pathogen-associated molecular patterns (PAMP) lipopolysaccharide (LPS) and Pam3Cys. To determine whether estradiol (E2) modulates PAMP-induced CCL20/MIP3alpha and TNF-alpha secretion, primary cultures of rat UEC were incubated with E2 for 24 h and then treated with LPS or Pam3Cys or not treated for an additional 12 h. E2 inhibited the constitutive secretion of TNF-alpha and CCL20/MIP3alpha into culture media. Interestingly, E2 pretreatment enhanced CCL20/MIP3alpha secretion due to …
Erythroid Cell-Specific Α-Globin Gene Regulation By The Cp2 Transcription Factor Family, Ho C. Kang, Jui Hyung Chae, Yeon H. Lee, Mi-Ae Park, June Ho Shin, Sung-Hyun Kim, Sang-Kyu Ye, Yoon Shin Cho, Steven Fiering, Chul Geun Kim
Erythroid Cell-Specific Α-Globin Gene Regulation By The Cp2 Transcription Factor Family, Ho C. Kang, Jui Hyung Chae, Yeon H. Lee, Mi-Ae Park, June Ho Shin, Sung-Hyun Kim, Sang-Kyu Ye, Yoon Shin Cho, Steven Fiering, Chul Geun Kim
Dartmouth Scholarship
We previously demonstrated that ubiquitously expressed CP2c exerts potent erythroid-specific transactivation of alpha-globin through an unknown mechanism. This mechanism is reported here to involve specific CP2 splice variants and protein inhibitor of activated STAT1 (PIAS1). We identify a novel murine splice isoform of CP2, CP2b, which is identical to CP2a except that it has an additional 36 amino acids encoded by an extra exon. CP2b has an erythroid cell-specific transcriptional activation domain, which requires the extra exon and can form heteromeric complexes with other CP2 isoforms, but lacks the DNA binding activity found in CP2a and CP2c. Transcriptional activation of …
Immune Responses Of Different Mouse Strains After Challenge With Equivalent Lethal Doses Of Toxoplasma Gondii, Y. H. Lee, L. H. Kasper
Immune Responses Of Different Mouse Strains After Challenge With Equivalent Lethal Doses Of Toxoplasma Gondii, Y. H. Lee, L. H. Kasper
Dartmouth Scholarship
Most immunological studies that utilize different strains of inbred mice following T. gondii infection fail to compensate for differences in host susceptibility to the size of the parasite innoculum. To address this concern, susceptible C57BL/6 and resistant CBA/J mice were orally infected with either an equivalent 50 % lethal dose (LD50) of brain cysts of the 76K strain of T. gondii (15 cysts in C57BL/6, 400 cysts in CBA/J) or the same dose of parasites in each mouse strain. C57BL/6 mice receiving 400 cysts (LD50 of CBA/J mice) died post infection, whereas CBA/J mice that received 15 …
Lineage-Restricted Function Of Nuclear Factor Kappab-Inducing Kinase (Nik) In Transducing Signals Via Cd40., Norman Garceau, Yoko Kosaka, Sally Masters, John Hambor, Reiko Shinkura, Tasuko Honjo, Randolph J. Noelle
Lineage-Restricted Function Of Nuclear Factor Kappab-Inducing Kinase (Nik) In Transducing Signals Via Cd40., Norman Garceau, Yoko Kosaka, Sally Masters, John Hambor, Reiko Shinkura, Tasuko Honjo, Randolph J. Noelle
Dartmouth Scholarship
CD40 signaling in B cells and dendritic cells (DCs) is critical for the development of humoral and cell-mediated immunity, respectively. Nuclear factor kappaB (NF-kappaB)-inducing kinase (NIK) has been implicated as a central transducing kinase in CD40-dependent activation. Here, we show that although NIK is essential for B cell activation, it is dispensable for activation of DCs. Such data provide compelling evidence that different intermediary kinases are used by different cellular lineages to trigger NF-kappaB activation via CD40.
Inhibition Of Growth Of Toxoplasma Gondii In Cultured Fibroblasts By Human Recombinant Gamma Interferon., E. R. Pfefferkorn, Paul M. Guyre
Inhibition Of Growth Of Toxoplasma Gondii In Cultured Fibroblasts By Human Recombinant Gamma Interferon., E. R. Pfefferkorn, Paul M. Guyre
Dartmouth Scholarship
The growth of Toxoplasma gondii in cultured human fibroblasts was inhibited by recombinant human gamma interferon at concentrations of 8 to 16 U/ml. The interferon was titrated by observing a total inhibition of parasite plaque formation 7 days after infection. Inhibition of the growth of T. gondii in the early days after infection was measured by marked reductions in the incorporation of radioactive uracil, a precursor that can only be used by the parasites. This assay showed that when cells were pretreated with gamma interferon for 1 day and then infected, inhibition of T. gondii growth could be readily detected …
Interferon Gamma Blocks The Growth Of Toxoplasma Gondii In Human Fibroblasts By Inducing The Host Cells To Degrade Tryptophan., E. R. Pfefferkorn
Interferon Gamma Blocks The Growth Of Toxoplasma Gondii In Human Fibroblasts By Inducing The Host Cells To Degrade Tryptophan., E. R. Pfefferkorn
Dartmouth Scholarship
Treatment of human fibroblasts with human recombinant gamma interferon blocked the growth of Toxoplasma gondii, an obligate intracellular protozoan parasite. Growth of the parasite was measured by a plaque assay 7 days after infection or by the incorporation of [3H]uracil 1 or 2 days after infection. The antitoxoplasma activity induced in the host cells by gamma interferon was strongly dependent upon the tryptophan concentration of the medium. Progressively higher minimal inhibitory concentrations of gamma interferon were observed as the tryptophan concentration in the culture medium was increased. Treatment with gamma interferon did not make the cells impermeable to tryptophan. The …