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Articles 1 - 9 of 9

Full-Text Articles in Medical Sciences

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 Dec 2013

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 …


Use Of Irf-3 And/Or Irf-7 Knockout Mice To Study Viral Pathogenesis: Lessons From A Murine Retrovirus-Induced Aids Model, Megan A. O'Connor, William R. Green Dec 2013

Use Of Irf-3 And/Or Irf-7 Knockout Mice To Study Viral Pathogenesis: Lessons From A Murine Retrovirus-Induced Aids Model, Megan A. O'Connor, William R. Green

Dartmouth Scholarship

Interferon regulatory factor (IRF) regulation of the type I interferon response has not been extensively explored in murine retroviral infections. IRF-3(-/-) and select IRF-3/7(-/-) mice were resistant to LP-BM5-induced pathogenesis. However, further analyses strongly suggested that resistance could be attributed to strain 129-specific contamination of the known retrovirus resistance gene Fv1. Therefore, caution should be taken when interpreting phenotypes observed in these knockout mice, as strain 129-derived genetic polymorphisms may explain observed differences.


Unique Microbial Communities Persist In Individual Cystic Fibrosis Patients Throughout A Clinical Exacerbation, Katherine E. Price, Thomas H. Hampton, Alex H. Gifford, Emily L. Dolben, Deborah A. Hogan, Hilary G. Morrison, Mitchell L. Sogin, George A. O’Tooled Nov 2013

Unique Microbial Communities Persist In Individual Cystic Fibrosis Patients Throughout A Clinical Exacerbation, Katherine E. Price, Thomas H. Hampton, Alex H. Gifford, Emily L. Dolben, Deborah A. Hogan, Hilary G. Morrison, Mitchell L. Sogin, George A. O’Tooled

Dartmouth Scholarship

Cystic fibrosis (CF) is caused by inherited mutations in the cystic fibrosis transmembrane conductance regulator gene and results in a lung environment that is highly conducive to polymicrobial infection. Over a lifetime, decreasing bacterial diversity and the presence of Pseudomonas aeruginosa in the lung are correlated with worsening lung disease. However, to date, no change in community diversity, overall microbial load or individual microbes has been shown to correlate with the onset of an acute exacerbation in CF patients. We followed 17 adult CF patients throughout the course of clinical exacerbation, treatment and recovery, using deep sequencing and quantitative PCR …


An Mll-Dependent Network Sustains Hematopoiesis, Erika L. Artinger, Bibhu P. Mishra, Kristin M. Zaffuto, Bin E. Li, Elaine K. Y. Chung, Adrian W. Moore, Yufei Chen, Chao Cheng, Patricia Ernst Jul 2013

An Mll-Dependent Network Sustains Hematopoiesis, Erika L. Artinger, Bibhu P. Mishra, Kristin M. Zaffuto, Bin E. Li, Elaine K. Y. Chung, Adrian W. Moore, Yufei Chen, Chao Cheng, Patricia Ernst

Dartmouth Scholarship

The histone methyltransferase Mixed Lineage Leukemia (MLL) is essential to maintain hematopoietic stem cells and is a leukemia protooncogene. Although clustered homeobox genes are well-characterized targets of MLL and MLL fusion oncoproteins, the range of Mll-regulated genes in normal hematopoietic cells remains unknown. Here, we identify and characterize part of the Mll-dependent transcriptional network in hematopoietic stem cells with an integrated approach by using conditional loss-of-function models, genomewide expression analyses, chromatin immunoprecipitation, and functional rescue assays. The Mll-dependent transcriptional network extends well beyond the previously appreciated Hox targets, is comprised of many characterized regulators of self-renewal, and contains target genes …


Pouring Salt On A Wound: Pseudomonas Aeruginosa Virulence Factors Alter Na+ And Cl− Flux In The Lung, Alicia E. Ballok, George A. O'Toole Jul 2013

Pouring Salt On A Wound: Pseudomonas Aeruginosa Virulence Factors Alter Na+ And Cl− Flux In The Lung, Alicia E. Ballok, George A. O'Toole

Dartmouth Scholarship

Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen with multiple niches in the human body, including the lung. P. aeruginosa infections are particularly damaging or fatal for patients with ventilator-associated pneumonia, chronic obstructive pulmonary disease, and cystic fibrosis (CF). To establish an infection, P. aeruginosa relies on a suite of virulence factors, including lipopolysaccharide, phospholipases, exoproteases, phenazines, outer membrane vesicles, type III secreted effectors, flagella, and pili. These factors not only damage the epithelial cell lining but also induce changes in cell physiology and function such as cell shape, membrane permeability, and protein synthesis. While such virulence factors are important in …


Anr And Its Activation By Plch Activity In Pseudomonas Aeruginosa Host Colonization And Virulence, Angelyca A. Jackson, Maegan J. Gross, Emily F. Daniels, Thomas H. Hampton, John H. Hammond, Isabelle Vallet-Gely, Simon L. Dove, Bruce A. Stanton, Deborah A. Hogan May 2013

Anr And Its Activation By Plch Activity In Pseudomonas Aeruginosa Host Colonization And Virulence, Angelyca A. Jackson, Maegan J. Gross, Emily F. Daniels, Thomas H. Hampton, John H. Hammond, Isabelle Vallet-Gely, Simon L. Dove, Bruce A. Stanton, Deborah A. Hogan

Dartmouth Scholarship

Pseudomonas aeruginosa hemolytic phospholipase C (PlcH) degrades phosphatidylcholine (PC), an abundant lipid in cell membranes and lung surfactant. A ΔplcHR mutant, known to be defective in virulence in animal models, was less able to colonize epithelial cell monolayers and was defective in biofilm formation on plastic when grown in lung surfactant. Microarray analyses found that strains defective in PlcH production had lower levels of Anr-regulated transcripts than the wild type. PC degradation stimulated the Anr regulon in an Anr-dependent manner under conditions where Anr activity was submaximal because of the presence of oxygen. Two PC catabolites, choline and glycine …


Secretion Of Tcpf By The Vibrio Cholerae Toxin-Coregulated Pilus Biogenesis Apparatus Requires An N-Terminal Determinant, Christina J. Megli, Ronald K. Taylor Apr 2013

Secretion Of Tcpf By The Vibrio Cholerae Toxin-Coregulated Pilus Biogenesis Apparatus Requires An N-Terminal Determinant, Christina J. Megli, Ronald K. Taylor

Dartmouth Scholarship

Type IV pili are important for microcolony formation, biofilm formation, twitching motility, and attachment. We and others have shown that type IV pili are important for protein secretion across the outer membrane, similar to type II secretion systems. This study explored the relationship between protein secretion and pilus formation in Vibrio cholerae. The toxin-coregulated pilus (TCP), a type IV pilus required for V. cholerae pathogenesis, is necessary for the secretion of the colonization factor TcpF (T. J. Kirn, N. Bose, and R. K. Taylor, Mol. Microbiol. 49:81–92, 2003). This phenomenon is not unique to V. cholerae; secreted …


Characterization Of Brer Interaction With The Bile Response Promoters Breab And Brer In Vibrio Cholerae, Francisca A. Cerda-Maira, Gabriela Kovacikova, Brooke A. Jude, Karen Skorupski, Ronald Taylor Jan 2013

Characterization Of Brer Interaction With The Bile Response Promoters Breab And Brer In Vibrio Cholerae, Francisca A. Cerda-Maira, Gabriela Kovacikova, Brooke A. Jude, Karen Skorupski, Ronald Taylor

Dartmouth Scholarship

The Vibrio cholerae BreR protein is a transcriptional repressor of the breAB efflux system operon, which encodes proteins involved in bile resistance. In a previous study (F. A. Cerda-Maira, C. S. Ringelberg, and R. K. Taylor, J. Bacteriol. 190:7441-7452, 2008), we used gel mobility shift assays to determine that BreR binds at two independent binding sites at the breAB promoter and a single site at its own promoter. Here it is shown, by DNase I footprinting and site-directed mutagenesis, that BreR is able to bind at a distal and a proximal site in the breAB promoter. However, only one of …


Inhibition Of The Host Translation Shutoff Response By Herpes Simplex Virus 1 Triggers Nuclear Envelope-Derived Autophagy, Kerstin Radtke, Luc English, Christiane Rondeau, David Leib Jan 2013

Inhibition Of The Host Translation Shutoff Response By Herpes Simplex Virus 1 Triggers Nuclear Envelope-Derived Autophagy, Kerstin Radtke, Luc English, Christiane Rondeau, David Leib

Dartmouth Scholarship

Macroautophagy is a cellular pathway that degrades intracellular pathogens and contributes to antigen presentation. Herpes simplex virus 1 (HSV-1) infection triggers both macroautophagy and an additional form of autophagy that uses the nuclear envelope as a source of membrane. The present study constitutes the first in-depth analysis of nuclear envelope-derived autophagy (NEDA). We established LC3a as a marker that allowed us to distinguish between NEDA and macroautophagy in both immunofluorescence and flow cytometry. NEDA was observed in many different cell types, indicating that it is a general response to HSV-1 infection. This autophagic pathway is known to depend on the …