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Articles 1 - 30 of 74
Full-Text Articles in Medical Microbiology
Molecular Characterization Of A Tetraspanin From The Human Liver Fluke, Opisthorchis Viverrini, Supawadee Piratae, Smarn Tesana, Malcolm K. Jones, Paul J. Brindley, Alex Loukas, Erica Lovas, Veerachai Eursitthichai, Banchob Sripa, Sirikanda Thanasuwan, Thewarach Laha
Molecular Characterization Of A Tetraspanin From The Human Liver Fluke, Opisthorchis Viverrini, Supawadee Piratae, Smarn Tesana, Malcolm K. Jones, Paul J. Brindley, Alex Loukas, Erica Lovas, Veerachai Eursitthichai, Banchob Sripa, Sirikanda Thanasuwan, Thewarach Laha
Microbiology, Immunology, and Tropical Medicine Faculty Publications
Background
The human liver fluke, Opisthorchis viverrini, is designated as a group 1 carcinogen, and is the major risk factor for cholangiocarcinoma in endemic countries throughout Southeast Asia. Proteins in the excretory-secretory products and tegumental surface membranes of the fluke have been proposed to play pivotal roles in parasite survival in the host, and subsequent pathogenesis. These macromolecules are therefore valid targets for the development of vaccines and new drugs to control the infection. Tetraspanins (TSP) are prominent components of the tegument of blood flukes where they are essential for tegument formation, are directly exposed to the immune system, …
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 …
Ccpa Regulates Arginine Biosynthesis In Staphylococcus Aureus Through Repression Of Proline Catabolism., Austin S. Nuxoll, Steven M. Halouska, Marat Sadykov, Mark L. Hanke, Kenneth W. Bayles, Tammy Kielian, Robert Powers, Paul D. Fey
Ccpa Regulates Arginine Biosynthesis In Staphylococcus Aureus Through Repression Of Proline Catabolism., Austin S. Nuxoll, Steven M. Halouska, Marat Sadykov, Mark L. Hanke, Kenneth W. Bayles, Tammy Kielian, Robert Powers, Paul D. Fey
Journal Articles: Pathology and Microbiology
Staphylococcus aureus is a leading cause of community-associated and nosocomial infections. Imperative to the success of S. aureus is the ability to adapt and utilize nutrients that are readily available. Genomic sequencing suggests that S. aureus has the genes required for synthesis of all twenty amino acids. However, in vitro experimentation demonstrates that staphylococci have multiple amino acid auxotrophies, including arginine. Although S. aureus possesses the highly conserved anabolic pathway that synthesizes arginine via glutamate, we demonstrate here that inactivation of ccpA facilitates the synthesis of arginine via the urea cycle utilizing proline as a substrate. Mutations within putA, rocD, …
Systematic Review Of Tst Responses In People Living With Hiv In Under-Resourced Settings: Implications For Isoniazid Preventive Therapy., Andrew D. Kerkhoff, Katharina Kranzer, Taraz Samandari, Jessica Nakiyingi-Miiro, Christopher C. Whalen, Anthony D. Harries, Stephen D. Lawn
Systematic Review Of Tst Responses In People Living With Hiv In Under-Resourced Settings: Implications For Isoniazid Preventive Therapy., Andrew D. Kerkhoff, Katharina Kranzer, Taraz Samandari, Jessica Nakiyingi-Miiro, Christopher C. Whalen, Anthony D. Harries, Stephen D. Lawn
Microbiology, Immunology, and Tropical Medicine Faculty Publications
Background
People living with HIV (PLWH) who have positive tuberculin skin tests (TST) benefit from isoniazid preventive therapy (IPT) whereas those testing TST-negative do not. Revised World Health Organization guidelines explicitly state that assessment of TST is not a requirement for initiation of IPT. However, it is not known what proportions of patients will benefit from IPT if implemented without targeting according to TST status. We therefore determined the proportions of PLWH who test TST-positive.
Methodology/Principal Findings
We systematically reviewed the literature published between January 1990 and February 2012 to determine the proportions of patients without active tuberculosis attending HIV …
Inla Promotes Dissemination Of Listeria Monocytogenes To The Mesenteric Lymph Nodes During Food Borne Infection Of Mice, Elsa N. Bou Ghanem, Grant S. Jones, Tanya Myers-Morales, Pooja D. Patil, Achmad N. Hidayatullah, Sarah E. F. D'Orazio
Inla Promotes Dissemination Of Listeria Monocytogenes To The Mesenteric Lymph Nodes During Food Borne Infection Of Mice, Elsa N. Bou Ghanem, Grant S. Jones, Tanya Myers-Morales, Pooja D. Patil, Achmad N. Hidayatullah, Sarah E. F. D'Orazio
Microbiology, Immunology, and Molecular Genetics Faculty Publications
Intestinal Listeria monocytogenes infection is not efficient in mice and this has been attributed to a low affinity interaction between the bacterial surface protein InlA and E-cadherin on murine intestinal epithelial cells. Previous studies using either transgenic mice expressing human E-cadherin or mouse-adapted L. monocytogenes expressing a modified InlA protein (InlA(m)) with high affinity for murine E-cadherin showed increased efficiency of intragastric infection. However, the large inocula used in these studies disseminated to the spleen and liver rapidly, resulting in a lethal systemic infection that made it difficult to define the natural course of intestinal infection. We describe here a …
Immune Correlates Of Aging In Outdoor-Housed Captive Rhesus Macaques (Macaca Mulatta), Elizabeth S. Didier, Chie Sugimoto, Lisa C. Bowers, Imtiaz A. Khan, Marcelo J. Kuroda
Immune Correlates Of Aging In Outdoor-Housed Captive Rhesus Macaques (Macaca Mulatta), Elizabeth S. Didier, Chie Sugimoto, Lisa C. Bowers, Imtiaz A. Khan, Marcelo J. Kuroda
Microbiology, Immunology, and Tropical Medicine Faculty Publications
Background
Questions remain about whether inflammation is a cause, consequence, or coincidence of aging. The purpose of this study was to define baseline immunological characteristics from blood to develop a model in rhesus macaques that could be used to address the relationship between inflammation and aging. Hematology, flow cytometry, clinical chemistry, and multiplex cytokine/chemokine analyses were performed on a group of 101 outdoor-housed captive rhesus macaques ranging from 2 to 24 years of age, approximately equivalent to 8 to 77 years of age in humans.
Results
These results extend earlier reports correlating changes in lymphocyte subpopulations and cytokines/chemokines with increasing …
Multifactorial Patterns Of Gene Expression In Colonic Epithelial Cells Predict Disease Phenotypes In Experimental Colitis, Aubrey Leigh Frantz, Maria E. C. Bruno, Eric William Rogier, Halide Tuna, Donald A. Cohen, Subbarao Bondada, Ralph Lakshman Chelvarajan, J. Anthony Brandon, C. Darrell Jennings, Charlotte S. Kaetzel
Multifactorial Patterns Of Gene Expression In Colonic Epithelial Cells Predict Disease Phenotypes In Experimental Colitis, Aubrey Leigh Frantz, Maria E. C. Bruno, Eric William Rogier, Halide Tuna, Donald A. Cohen, Subbarao Bondada, Ralph Lakshman Chelvarajan, J. Anthony Brandon, C. Darrell Jennings, Charlotte S. Kaetzel
Microbiology, Immunology, and Molecular Genetics Faculty Publications
Background— The pathogenesis of inflammatory bowel disease (IBD) is complex and the need to identify molecular biomarkers is critical. Epithelial cells play a central role in maintaining intestinal homeostasis. We previously identified five “signature” biomarkers in colonic epithelial cells (CEC) that are predictive of disease phenotype in Crohn's disease. Here we investigate the ability of CEC biomarkers to define the mechanism and severity of intestinal inflammation.
Methods— We analyzed the expression of RelA, A20, pIgR, tumor necrosis factor (TNF), and macrophage inflammatory protein (MIP)-2 in CEC of mice with dextran sodium sulfate (DSS) acute colitis or T-cell-mediated chronic colitis. …
Escherichia Coli Recg Functionally Suppresses Human Bloom Syndrome Phenotypes, Michael W. Killen, Dawn M. Stults, William A. Wilson, Andrew J. Pierce
Escherichia Coli Recg Functionally Suppresses Human Bloom Syndrome Phenotypes, Michael W. Killen, Dawn M. Stults, William A. Wilson, Andrew J. Pierce
Microbiology, Immunology, and Molecular Genetics Faculty Publications
Defects in the human BLM gene cause Bloom syndrome, notable for early development of tumors in a broad variety of tissues. On the basis of sequence similarity, BLM has been identified as one of the five human homologs of RecQ from Escherichia coli. Nevertheless, biochemical characterization of the BLM protein indicates far greater functional similarity to the E. coli RecG protein and there is no known RecG homolog in human cells. To explore the possibility that the shared biochemistries of BLM and RecG may represent an example of convergent evolution of cellular function where in humans BLM has evolved to …
Gene Expression Analysis Of A Murine Model With Pulmonary Vascular Remodeling Compared To End-Stage Ipah Lungs, Kayoko Shimodaira, Yoichiro Okubo, Eri Ochiai, Haruo Nakayama, Harutaka Katano, Megumi Wakayama, Minoru Shinozaki, Takao Ishiwatari, Daisuke Sasai, Naobumi Tochigi, Tetsuo Nemoto, Tsutomu Saji, Katsuhiko Kamei, Kazutoshi Shibuya
Gene Expression Analysis Of A Murine Model With Pulmonary Vascular Remodeling Compared To End-Stage Ipah Lungs, Kayoko Shimodaira, Yoichiro Okubo, Eri Ochiai, Haruo Nakayama, Harutaka Katano, Megumi Wakayama, Minoru Shinozaki, Takao Ishiwatari, Daisuke Sasai, Naobumi Tochigi, Tetsuo Nemoto, Tsutomu Saji, Katsuhiko Kamei, Kazutoshi Shibuya
Microbiology, Immunology, and Molecular Genetics Faculty Publications
BACKGROUND: Idiopathic pulmonary arterial hypertension (IPAH) continues to be one of the most serious intractable diseases that might start with activation of several triggers representing the genetic susceptibility of a patient. To elucidate what essentially contributes to the onset and progression of IPAH, we investigated factors playing an important role in IPAH by searching discrepant or controversial expression patterns between our murine model and those previously published for human IPAH. We employed the mouse model, which induced muscularization of pulmonary artery leading to hypertension by repeated intratracheal injection of Stachybotrys chartarum, a member of nonpathogenic and ubiquitous fungus in our …
Immune Clearance Of Attenuated Rabies Virus Results In Neuronal Survival With Altered Gene Expression., Emily A Gomme, Christoph Wirblich, Sankar Addya, Glenn F Rall, Matthias J Schnell
Immune Clearance Of Attenuated Rabies Virus Results In Neuronal Survival With Altered Gene Expression., Emily A Gomme, Christoph Wirblich, Sankar Addya, Glenn F Rall, Matthias J Schnell
Department of Microbiology and Immunology Faculty Papers
Rabies virus (RABV) is a highly neurotropic pathogen that typically leads to mortality of infected animals and humans. The precise etiology of rabies neuropathogenesis is unknown, though it is hypothesized to be due either to neuronal death or dysfunction. Analysis of human brains post-mortem reveals surprisingly little tissue damage and neuropathology considering the dramatic clinical symptomology, supporting the neuronal dysfunction model. However, whether or not neurons survive infection and clearance and, provided they do, whether they are functionally restored to their pre-infection phenotype has not been determined in vivo for RABV, or any neurotropic virus. This is due, in part, …
Nonthermal Plasma Jet Efficacy On Candida Kefyr, Amber Marie Mattson Jackson
Nonthermal Plasma Jet Efficacy On Candida Kefyr, Amber Marie Mattson Jackson
Electrical & Computer Engineering Theses & Dissertations
The inactivation abilities of a nonthermal plasma jet were investigated with the yeast C. kefyr, a pathogen with increasing importance in healthcare. The plasma is generated using a microhollow cathode discharge (MHCD) geometry operated with a DC voltage of 2 kV and a current of 30 mA using air as the operating gas at an airflow rate of 8 SLM. The plasma discharge approaches room temperature at a few mm away from the plasma jet allowing for the use on heat sensitive surfaces. Dry air and humid air were used as the operating gas to see if humidity plays …
An Analysis Of The Incidence Of Antibiotic Resistant Infections In The State Of New Hampshire, Melanie Duhamel
An Analysis Of The Incidence Of Antibiotic Resistant Infections In The State Of New Hampshire, Melanie Duhamel
Honors Theses and Capstones
The purpose of this research paper is to study, analyze, and characterize antibiotic resistance in both the theoretical and investigative contexts. After an in-depth examination of the literature and previous research investigating the definition, origin, affected organisms, and proposed coping mechanisms related to antibiotic resistance, a research plan was organized and executed.
The organism Methicillin Resistant Staphylococcus aureus (MRSA) was selected as the focus of study because of abundant current research and regulated monitoring of this organism in healthcare organizations. Data about the incidence rates of MRSA in theUnited States was collected from reports disseminated by the Center for Disease …
Latexin Is Down-Regulated In Hematopoietic Malignancies And Restoration Of Expression Inhibits Lymphoma Growth, Yi Liu, Dianna Howard, Kyle Rector, Carol Swiderski, Jason Brandon, Lawrence Schook, Jayesh Mehta, J. Scott Bryson, Subbarao Bondada, Ying Liang
Latexin Is Down-Regulated In Hematopoietic Malignancies And Restoration Of Expression Inhibits Lymphoma Growth, Yi Liu, Dianna Howard, Kyle Rector, Carol Swiderski, Jason Brandon, Lawrence Schook, Jayesh Mehta, J. Scott Bryson, Subbarao Bondada, Ying Liang
Internal Medicine Faculty Publications
Latexin is a negative regulator of hematopoietic stem cell number in mice. Its dysregulated expression in other tumors led us to hypothesize that latexin may have tumor suppressor properties in hematological malignancies. We found that latexin was down-regulated in a variety of leukemia and lymphoma cell lines as well as in CD34+ cells from the blood and marrow of patients with these malignancies. 5-aza-2'-deoxycytodine treatment and bisulfite sequencing revealed hypermethylation of latexin promoter in tumor cells. Retrovirus-mediated latexin overexpression in A20 mouse lymphoma cells inhibited their in vitro growth by 16 fold and in vivo tumor volume by 2 fold. …
Herpes Simplex Virus 34.5 Interferes With Autophagosome Maturation And Antigen Presentation In Dendritic Cells, Philipe A. M. Gobeil, David A. Leib
Herpes Simplex Virus 34.5 Interferes With Autophagosome Maturation And Antigen Presentation In Dendritic Cells, Philipe A. M. Gobeil, David A. Leib
Dartmouth Scholarship
The cellular autophagy response induced by herpes simplex virus 1 (HSV-1) is countered by the viral γ34.5 protein. γ34.5 modulates autophagy by binding to the host autophagy protein Beclin-1 and through this binding inhibits the formation of autophagosomes in fibroblasts and neurons. In contrast, in this study dendritic cells (DCs) infected with HSV-1 showed an accumulation of autophagosomes and of the long-lived protein p62. No such accumulations were observed in DCs infected with a γ34.5-null virus or a virus lacking the Beclin-binding domain (BBD) of γ34.5. To explore this further, we established stably transduced DC lines to show that γ34.5 …
Serial Analysis Of The Gut And Respiratory Microbiome In Cystic Fibrosis In Infancy: Interaction Between Intestinal And Respiratory Tracts And Impact Of Nutritional Exposures, J. C. Madan, D. C. Koestler, B. A. Stanton, L. Davidson, L. A. Moulton, M. L. Housman, J. H. Moore, M. F. Guill, H. G. Morrison, M. L. Sogin, T. H. Hampton, M. R. Karagas, P. E. Palumbo, J. A. Foster, P. L. Hibberd, G. A. O’Toole
Serial Analysis Of The Gut And Respiratory Microbiome In Cystic Fibrosis In Infancy: Interaction Between Intestinal And Respiratory Tracts And Impact Of Nutritional Exposures, J. C. Madan, D. C. Koestler, B. A. Stanton, L. Davidson, L. A. Moulton, M. L. Housman, J. H. Moore, M. F. Guill, H. G. Morrison, M. L. Sogin, T. H. Hampton, M. R. Karagas, P. E. Palumbo, J. A. Foster, P. L. Hibberd, G. A. O’Toole
Dartmouth Scholarship
Pulmonary damage caused by chronic colonization of the cystic fibrosis (CF) lung by microbial communities is the proximal cause of respiratory failure. While there has been an effort to document the microbiome of the CF lung in pediatric and adult patients, little is known regarding the developing microflora in infants. We examined the respiratory and intestinal microbiota development in infants with CF from birth to 21 months. Distinct genera dominated in the gut compared to those in the respiratory tract, yet some bacteria overlapped, demonstrating a core microbiota dominated by Veillonella and Streptococcus. Bacterial diversity increased significantly over time, …
Virus-Producing Cells Determine The Host Protein Profiles Of Hiv-1 Virion Cores, Steven Santos, Yuri Obukhov, Sergei Nekhai, Michael Bukrinsky, Sergey Iordanskiy
Virus-Producing Cells Determine The Host Protein Profiles Of Hiv-1 Virion Cores, Steven Santos, Yuri Obukhov, Sergei Nekhai, Michael Bukrinsky, Sergey Iordanskiy
Microbiology, Immunology, and Tropical Medicine Faculty Publications
Background
Upon HIV entry into target cells, viral cores are released and rearranged into reverse transcription complexes (RTCs), which support reverse transcription and also protect and transport viral cDNA to the site of integration. RTCs are composed of viral and cellular proteins that originate from both target and producer cells, the latter entering the target cell within the viral core. However, the proteome of HIV-1 viral cores in the context of the type of producer cells has not yet been characterized.
Results
We examined the proteomic profiles of the cores purified from HIV-1 NL4-3 virions assembled in Sup-T1 cells (T …
Gut Microbiome Composition Is Linked To Whole Grain-Induced Immunological Improvements, Ines Martinez, James M. Lattimer, Kelcie L. Hubach, Jennifer A. Case, Junyi Yang, Casey G. Weber, Julie A. Louk, Devin J. Rose, Gayaneh Kyureghian, Daniel A. Peterson, Mark D. Haub, Jens Walter
Gut Microbiome Composition Is Linked To Whole Grain-Induced Immunological Improvements, Ines Martinez, James M. Lattimer, Kelcie L. Hubach, Jennifer A. Case, Junyi Yang, Casey G. Weber, Julie A. Louk, Devin J. Rose, Gayaneh Kyureghian, Daniel A. Peterson, Mark D. Haub, Jens Walter
Food for Health: Publications
The involvement of the gut microbiota in metabolic disorders, and the ability of whole grains to affect both host metabolism and gut microbial ecology, suggest that some benefits of whole grains are mediated through their effects on the gut microbiome. Nutritional studies that assess the effect of whole grains on both the gut microbiome and human physiology are needed. We conducted a randomized cross-over trial with four-week treatments in which 28 healthy humans consumed a daily dose of 60 g of whole-grain barley (WGB), brown rice (BR), or an equal mixture of the two (BR+WGB), and characterized their impact on …
Microbiological Components In Mainstream And Sidestream Cigarette Smoke, Lennart Larsson, Christina Pehrson, Tenzin Dechen, Mardi Crane-Godreau
Microbiological Components In Mainstream And Sidestream Cigarette Smoke, Lennart Larsson, Christina Pehrson, Tenzin Dechen, Mardi Crane-Godreau
Dartmouth Scholarship
Research has shown that tobacco smoke contains substances of microbiological origin such as ergosterol (a fungal membrane lipid) and lipopolysaccharide (LPS) (in the outer membrane of Gram-negative bacteria). The aim of the present study was to compare the amounts of ergosterol and LPS in the tobacco and mainstream (MS) and sidestream (SS) smoke of some popular US cigarettes. We measured LPS 3-hydroxy fatty acids and fungal biomass biomarker ergosterol in the tobacco and smoke from cigarettes of 11 popular brands purchased in the US. University of Kentucky reference cigarettes were also included for comparison.
The Crispr/Cas Adaptive Immune System Of Pseudomonas Aeruginosa Mediates Resistance To Naturally Occurring And Engineered Phages, Kyle C. Cady, Joe Bondy-Denomy, Gary E. Heussler, Alan R. Davidson, George A. O'Toole
The Crispr/Cas Adaptive Immune System Of Pseudomonas Aeruginosa Mediates Resistance To Naturally Occurring And Engineered Phages, Kyle C. Cady, Joe Bondy-Denomy, Gary E. Heussler, Alan R. Davidson, George A. O'Toole
Dartmouth Scholarship
Here we report the isolation of 6 temperate bacteriophages (phages) that are prevented from replicating within the laboratory strain Pseudomonas aeruginosa PA14 by the endogenous CRISPR/Cas system of this microbe. These phages are only the second identified group of naturally occurring phages demonstrated to be blocked for replication by a nonengineered CRISPR/Cas system, and our results provide the first evidence that the P. aeruginosa type I-F CRISPR/Cas system can function in phage resistance. Previous studies have highlighted the importance of the protospacer adjacent motif (PAM) and a proximal 8-nucleotide seed sequence in mediating CRISPR/Cas-based immunity. Through engineering of a protospacer …
Minor Pilins Of The Type Iv Pilus System Participate In The Negative Regulation Of Swarming Motility, S L. Kuchma, E. F. Griffin, G. A. O'Toole
Minor Pilins Of The Type Iv Pilus System Participate In The Negative Regulation Of Swarming Motility, S L. Kuchma, E. F. Griffin, G. A. O'Toole
Dartmouth Scholarship
Pseudomonas aeruginosa exhibits distinct surface-associated behaviors, including biofilm formation, flagellum-mediated swarming motility, and type IV pilus-driven twitching. Here, we report a role for the minor pilins, PilW and PilX, components of the type IV pilus assembly machinery, in the repression of swarming motility. Mutating either the pilW or pilX gene alleviates the inhibition of swarming motility observed for strains with elevated levels of the intracellular signaling molecule cyclic di-GMP (c-di-GMP) due to loss of BifA, a c-di-GMP-degrading phosphodiesterase. Blocking PilD peptidase-mediated processing of PilW and PilX renders the unprocessed proteins defective for pilus assembly but still functional in c-di-GMP-mediated swarming …
Molecular Mechanisms Of Aging And Immune System Regulation In Drosophila., Ioannis Eleftherianos, Julio C. Castillo
Molecular Mechanisms Of Aging And Immune System Regulation In Drosophila., Ioannis Eleftherianos, Julio C. Castillo
Microbiology, Immunology, and Tropical Medicine Faculty Publications
Aging is a complex process that involves the accumulation of deleterious changes resulting in overall decline in several vital functions, leading to the progressive deterioration in physiological condition of the organism and eventually causing disease and death. The immune system is the most important host-defense mechanism in humans and is also highly conserved in insects. Extensive research in vertebrates has concluded that aging of the immune function results in increased susceptibility to infectious disease and chronic inflammation. Over the years, interest has grown in studying the molecular interaction between aging and the immune response to pathogenic infections. The fruit fly …
Low Levels Of Β-Lactam Antibiotics Induce Extracellular Dna Release And Biofilm Formation In Staphylococcus Aureus., Jeffrey B. Kaplan, Era A. Izano, Prerna Gopal, Michael T. Karwacki, Sangho Kim, Jeffrey L. Bose, Kenneth W. Bayles, Alexander R. Horswill
Low Levels Of Β-Lactam Antibiotics Induce Extracellular Dna Release And Biofilm Formation In Staphylococcus Aureus., Jeffrey B. Kaplan, Era A. Izano, Prerna Gopal, Michael T. Karwacki, Sangho Kim, Jeffrey L. Bose, Kenneth W. Bayles, Alexander R. Horswill
Journal Articles: Pathology and Microbiology
UNLABELLED: Subminimal inhibitory concentrations of antibiotics have been shown to induce bacterial biofilm formation. Few studies have investigated antibiotic-induced biofilm formation in Staphylococcus aureus, an important human pathogen. Our goal was to measure S. aureus biofilm formation in the presence of low levels of β-lactam antibiotics. Fifteen phylogenetically diverse methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains were employed. Methicillin, ampicillin, amoxicillin, and cloxacillin were added to cultures at concentrations ranging from 0× to 1× MIC. Biofilm formation was measured in 96-well microtiter plates using a crystal violet binding assay. Autoaggregation was measured using a visual test tube …
Contribution Of The Staphylococcus Aureus Atl Am And Gl Murein Hydrolase Activities In Cell Division, Autolysis, And Biofilm Formation., Jeffrey L. Bose, Mckenzie K. Lehman, Paul D. Fey, Kenneth W. Bayles
Contribution Of The Staphylococcus Aureus Atl Am And Gl Murein Hydrolase Activities In Cell Division, Autolysis, And Biofilm Formation., Jeffrey L. Bose, Mckenzie K. Lehman, Paul D. Fey, Kenneth W. Bayles
Journal Articles: Pathology and Microbiology
The most prominent murein hydrolase of Staphylococcus aureus, AtlA, is a bifunctional enzyme that undergoes proteolytic cleavage to yield two catalytically active proteins, an amidase (AM) and a glucosaminidase (GL). Although the bifunctional nature of AtlA has long been recognized, most studies have focused on the combined functions of this protein in cell wall metabolism and biofilm development. In this study, we generated mutant derivatives of the clinical S. aureus isolate, UAMS-1, in which one or both of the AM and GL domains of AtlA have been deleted. Examination of these strains revealed that each mutant exhibited growth rates comparable …
The Importance Of Amino Acid Composition In Natural Amps: An Evolutional, Structural, And Functional Perspective., Biswajit Mishra, Guangshun Wang
The Importance Of Amino Acid Composition In Natural Amps: An Evolutional, Structural, And Functional Perspective., Biswajit Mishra, Guangshun Wang
Journal Articles: Pathology and Microbiology
No abstract provided.
Epoxide-Mediated Cifr Repression Of Cif Gene Expression Utilizes Two Binding Sites In Pseudomonas Aeruginosa, Alicia E. Ballok, Christopher D. Bahl, Emily L. Dolben, Allia K. Lindsay, Jessica D. St. Laurent, Deborah Hogan, Dean Madden, George A. O'Toole
Epoxide-Mediated Cifr Repression Of Cif Gene Expression Utilizes Two Binding Sites In Pseudomonas Aeruginosa, Alicia E. Ballok, Christopher D. Bahl, Emily L. Dolben, Allia K. Lindsay, Jessica D. St. Laurent, Deborah Hogan, Dean Madden, George A. O'Toole
Dartmouth Scholarship
Pseudomonas aeruginosa secretes an epoxide hydrolase virulence factor that reduces the apical membrane expression of ABC transporters such as the cystic fibrosis transmembrane conductance regulator (CFTR). This virulence factor, named CFTR inhibitory factor (Cif), is regulated by a TetR-family, epoxide-responsive repressor known as CifR via direct binding and repression. We identified two sites of CifR binding in the intergenic space between cifR and morB, the first gene in the operon containing the cif gene. We have mapped these binding sites and found they are 27 bp in length, and they overlap the -10 and +1 sites of both the cifR …
Gastrointestinal Cell Mediated Immunity And The Microsporidia, Magali M. Moretto, Imtiaz A. Khan, Louis M. Weiss
Gastrointestinal Cell Mediated Immunity And The Microsporidia, Magali M. Moretto, Imtiaz A. Khan, Louis M. Weiss
Microbiology, Immunology, and Tropical Medicine Faculty Publications
No abstract provided.
Germline Transgenesis And Insertional Mutagenesis In Schistosoma Mansoni Mediated By Murine Leukemia Virus, Gabriel Rinaldi, Sabine E. Eckert, Isheng J. Tsai, Suttas Suttiprapa, Kristine J. Kines, Jose F. Tort, Victoria H. Mann, Daniel J. Turner, Matthew Berriman, Paul J. Brindley
Germline Transgenesis And Insertional Mutagenesis In Schistosoma Mansoni Mediated By Murine Leukemia Virus, Gabriel Rinaldi, Sabine E. Eckert, Isheng J. Tsai, Suttas Suttiprapa, Kristine J. Kines, Jose F. Tort, Victoria H. Mann, Daniel J. Turner, Matthew Berriman, Paul J. Brindley
Microbiology, Immunology, and Tropical Medicine Faculty Publications
Functional studies will facilitate characterization of role and essentiality of newly available genome sequences of the human schistosomes, Schistosoma mansoni, S. japonicum and S. haematobium. To develop transgenesis as a functional approach for these pathogens, we previously demonstrated that pseudotyped murine leukemia virus (MLV) can transduce schistosomes leading to chromosomal integration of reporter transgenes and short hairpin RNA cassettes. Here we investigated vertical transmission of transgenes through the developmental cycle of S. mansoni after introducing transgenes into eggs. Although MLV infection of schistosome eggs from mouse livers was efficient in terms of snail infectivity, >10-fold higher transgene copy …
Microbial Co-Occurrence Relationships In The Human Microbiome, Karoline Faust, J. Fah Sathirapongsasuti, Jacques Izard, Dirk Gevers, Jeroen Raes, Curtis Huttenhower
Microbial Co-Occurrence Relationships In The Human Microbiome, Karoline Faust, J. Fah Sathirapongsasuti, Jacques Izard, Dirk Gevers, Jeroen Raes, Curtis Huttenhower
Department of Food Science and Technology: Faculty Publications
The healthy microbiota show remarkable variability within and among individuals. In addition to external exposures, ecological relationships (both oppositional and symbiotic) between microbial inhabitants are important contributors to this variation. It is thus of interest to assess what relationships might exist among microbes and determine their underlying reasons. The initial Human Microbiome Project (HMP) cohort, comprising 239 individuals and 18 different microbial habitats, provides an unprecedented resource to detect, catalog, and analyze such relationships. Here, we applied an ensemble method based on multiple similarity measures in combination with generalized boosted linear models (GBLMs) to taxonomic marker (16S rRNA gene) profiles …
Prevalence Of Streptococci And Increased Polymicrobial Diversity Associated With Cystic Fibrosis Patient Stability, L. M. Filkins, T. H. Hampton, A. H. Gifford, M. J. Gross, D. A. Hogan, M. L. Sogin, H. G. Morrison, B. J. Paster, G. A. O'Toole
Prevalence Of Streptococci And Increased Polymicrobial Diversity Associated With Cystic Fibrosis Patient Stability, L. M. Filkins, T. H. Hampton, A. H. Gifford, M. J. Gross, D. A. Hogan, M. L. Sogin, H. G. Morrison, B. J. Paster, G. A. O'Toole
Dartmouth Scholarship
Diverse microbial communities chronically colonize the lungs of cystic fibrosis patients. Pyrosequencing of amplicons for hypervariable regions in the 16S rRNA gene generated taxonomic profiles of bacterial communities for sputum genomic DNA samples from 22 patients during a state of clinical stability (outpatients) and 13 patients during acute exacerbation (inpatients). We employed quantitative PCR (qPCR) to confirm the detection of Pseudomonas aeruginosa and Streptococcus by the pyrosequencing data and human oral microbe identification microarray (HOMIM) analysis to determine the species of the streptococci identified by pyrosequencing. We show that outpatient sputum samples have significantly higher bacterial diversity than inpatients, but …
Il-4 Engagement Of The Type 1 Il-4 Receptor Complex Enhances Mouse Eosinophil Migration To Eotaxin-1 In Vitro, Nicola M. Heller, William M. Gwinn, Raymond P. Donnelly, Stephanie L. Constant, Achsah D. Keegan
Il-4 Engagement Of The Type 1 Il-4 Receptor Complex Enhances Mouse Eosinophil Migration To Eotaxin-1 In Vitro, Nicola M. Heller, William M. Gwinn, Raymond P. Donnelly, Stephanie L. Constant, Achsah D. Keegan
Microbiology, Immunology, and Tropical Medicine Faculty Publications
Background
Previous work from our laboratory demonstrated that IL-4Rα expression on a myeloid cell type was responsible for enhancement of Th2-driven eosinophilic inflammation in a mouse model of allergic lung inflammation. Subsequently, we have shown that IL-4 signaling through type I IL-4 receptors on monocytes/macrophages strongly induced activation of the IRS-2 pathway and a subset of genes characteristic of alternatively activated macrophages. The direct effect(s) of IL-4 and IL-13 on mouse eosinophils are not clear. The goal of this study was determine the effect of IL-4 and IL-13 on mouse eosinophil function.
Methods
Standard Transwell chemotaxis assay was used to …