Medical Microbiology Commons^™

Rna-Seq Of Borrelia Burgdorferi In Multiple Phases Of Growth Reveals Insights Into The Dynamics Of Gene Expression, Transcriptome Architecture, And Noncoding Rnas, William K. Arnold, Christina R. Savage, Catherine A. Brissette, Janakiram Seshu, Jonathan Livny, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Borrelia burgdorferi, the agent of Lyme disease, differentially expresses numerous genes and proteins as it cycles between mammalian hosts and tick vectors. Insights on regulatory mechanisms have been provided by earlier studies that examined B. burgdorferi gene expression patterns during cultivation. However, prior studies examined bacteria at only a single time point of cultivation, providing only a snapshot of what is likely a dynamic transcriptional program driving B. burgdorferi adaptations to changes during culture growth phases. To address that concern, we performed RNA sequencing (RNA-Seq) analysis of B. burgdorferi cultures at early-exponential, mid-exponential, and early-stationary phases …

Hiv-1 Integrates Widely Throughout The Genome Of The Human Blood Fluke Schistosoma Mansoni., Sutas Suttiprapa, Gabriel Rinaldi, Isheng J Tsai, Victoria H. Mann, Larisa Dubrovsky, Hong-Bin Yan, Nancy Holroyd, Thomas Huckvale, Caroline Durrant, Anna V Protasio, Tatiana Pushkarsky, Sergey Iordanskiy, Matthew Berriman, Michael I. Bukrinsky, Paul J. Brindley

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Schistosomiasis is the most important helminthic disease of humanity in terms of morbidity and mortality. Facile manipulation of schistosomes using lentiviruses would enable advances in functional genomics in these and related neglected tropical diseases pathogens including tapeworms, and including their non-dividing cells. Such approaches have hitherto been unavailable. Blood stream forms of the human blood fluke, Schistosoma mansoni, the causative agent of the hepatointestinal schistosomiasis, were infected with the human HIV-1 isolate NL4-3 pseudotyped with vesicular stomatitis virus glycoprotein. The appearance of strong stop and positive strand cDNAs indicated that virions fused to schistosome cells, the nucleocapsid internalized and the …

Kinase-Independent Function Of Rip1, Critical For Mature T-Cell Survival And Proliferation., John Bertin, Peter J. Gough, Jianke Zhang, John P. Dowling, Yubo Cai

Department of Microbiology and Immunology Faculty Papers

The death receptor, Fas, triggers apoptotic death and is essential for maintaining homeostasis in the peripheral lymphoid organs. RIP1 was originally cloned when searching for Fas-binding proteins and was later shown to associate also with the signaling complex of TNFR1. Although Fas exclusively induces apoptosis, TNFR1 primarily activates the pro-survival/pro-inflammatory NF-κB pathway. Mutations in Fas lead to lymphoproliferative (lpr) diseases, and deletion of TNFR1 results in defective innate immune responses. However, the function of RIP1 in the adult lymphoid system has not been well understood, primarily owing to perinatal lethality in mice lacking the entire RIP1 protein in germ cells. …

Immune- And Nonimmune-Compartment-Specific Interferon Responses Are Critical Determinants Of Herpes Simplex Virus-Induced Generalized Infections And Acute Liver Failure, Zachary M. Parker, Tracy Jo Pasieka, George A. Parker, David A. Leib

Dartmouth Scholarship

The interferon (IFN) response to viral pathogens is critical for host survival. In humans and mouse models, defects in IFN responses can result in lethal herpes simplex virus 1 (HSV-1) infections, usually from encephalitis. Although rare, HSV-1 can also cause fulminant hepatic failure, which is often fatal. Although herpes simplex encephalitis has been extensively studied, HSV-1 generalized infections and subsequent acute liver failure are less well understood. We previously demonstrated that IFN-αβγR-/- mice are exquisitely susceptible to liver infection following corneal infection with HSV-1. In this study, we used bone marrow chimeras of IFN-αβγR-/- (AG129) and wild-type (WT; 129SvEv) mice …

Heterogeneity Among Isolates Reveals That Fitness In Low Oxygen Correlates With Aspergillus Fumigatus Virulence, Caitlin H. Kowalski, Sarah R. Beattie, Kevin K. Fuller, Elizabeth A. Mcgurk, Yi-Wei Tang, Tobias Hohl, Joshua Obar, Robert Cramer Jr.

Dartmouth Scholarship

Previous work has shown that environmental and clinical isolates of Aspergillus fumigatus represent a diverse population that occupies a variety of niches, has extensive genetic diversity, and exhibits virulence heterogeneity in a number of animal models of invasive pulmonary aspergillosis (IPA). However, mechanisms explaining differences in virulence among A. fumigatus isolates remain enigmatic. Here, we report a significant difference in virulence of two common lab strains, CEA10 and AF293, in the murine triamcinolone immunosuppression model of IPA, in which we previously identified severe low oxygen microenvironments surrounding fungal lesions. Therefore, we hypothesize that the ability to thrive within these lesions …

Structural Diversity In The Type Iv Pili Of Multidrug-Resistant Acinetobacter, Kurt H. Piepenbrink, Erik Lillehoj, Christian M. Harding, Jason W. Labonte, Xiaotong Zuo, Chelsea A. Rapp, Robert S. Munson Jr, Simeon E. Goldblum, Mario F. Feldman, Jeffrey J. Gray, Eric J. Sundberg

Food for Health: Publications

Acinetobacter baumannii is a Gram-negative coccobacillus found primarily in hospital settings that has recently emerged as a source of hospital-acquired infections. A. baumannii expresses a variety of virulence factors, including type IV pili, bacterial extracellular appendages often essential for attachment to host cells. Here, we report the high resolution structures of the major pilin subunit, PilA, from three Acinetobacter strains, demonstrating thatA. baumannii subsets produce morphologically distinct type IV pilin glycoproteins. We examine the consequences of this heterogeneity for protein folding and assembly as well as host-cell adhesion by Acinetobacter. Comparisons of genomic and structural data with pilin proteins from …

Cmv-Specific Cd8 T Cell Differentiation And Localization: Implications For Adoptive Therapies., Corinne J Smith, Michael Quinn, Christopher M Snyder

Department of Microbiology and Immunology Faculty Papers

Human cytomegalovirus (HCMV) is a ubiquitous virus that causes chronic infection and, thus, is one of the most common infectious complications of immune suppression. Adoptive transfer of HCMV-specific T cells has emerged as an effective method to reduce the risk for HCMV infection and/or reactivation by restoring immunity in transplant recipients. However, the CMV-specific CD8(+) T cell response is comprised of a heterogenous mixture of subsets with distinct functions and localization, and it is not clear if current adoptive immunotherapy protocols can reconstitute the full spectrum of CD8(+) T cell immunity. The aim of this review is to briefly summarize …

The Neu1-Selective Sialidase Inhibitor, C9- Butyl-Amide-Dana, Blocks Sialidase Activity And Neu1-Mediated Bioactivities In Human Lung In Vitro And Murine Lung In Vivo, Sang W. Hyun, Anguo Liu, Zhenguo Liu, Alan S. Cross, Avelino C. Verceles, Sadagopan Magesh, Yadagiri Kommagalla, Chandrababunaidu Kona, Hiromune Ando, Irina G. Luzina, Sergei P. Atamas, Kurt H. Piepenbrink, Eric J. Sundberg, Wei Guang, Hideharu Ishida, Erik P. Lillehoj, Simeon E. Goldblum

Food for Health: Publications

Neuraminidase-1 (NEU1) is the predominant sialidase expressed in human airway epithelia and lung microvascular endothelia where it mediates multiple biological processes. We tested whether the NEU1-selective sialidase inhibitor, C9-butyl-amide-2-deoxy-2,3-dehydro-Nacetylneuraminic acid (C9-BA-DANA), inhibits one or more established NEU1-mediated bioactivities in human lung cells. We established the IC50 values of C9-BA-DANA for total sialidase activity in human airway epithelia, lung microvascular endothelia and lung fibroblasts to be 3.74 µM, 13.0 µM and 4.82 µM, respectively. In human airway epithelia, C9-BA-DANA dose-dependently inhibited flagellin-induced, NEU1-mediated mucin-1 ectodomain desialylation, adhesiveness for Pseudomonas aeruginosa and shedding. In lung microvascular endothelia, C9-BA-DANA reversed NEU1-driven restraint of …

The Global Economic And Health Burden Of Human Hookworm Infection., Sarah M Bartsch, Peter J. Hotez, Lindsey Asti, Kristina M Zapf, Maria Elena Bottazzi, David J. Diemert, Bruce Y Lee

Microbiology, Immunology, and Tropical Medicine Faculty Publications

BACKGROUND: Even though human hookworm infection is highly endemic in many countries throughout the world, its global economic and health impact is not well known. Without a better understanding of hookworm's economic burden worldwide, it is difficult for decision makers such as funders, policy makers, disease control officials, and intervention manufacturers to determine how much time, energy, and resources to invest in hookworm control.

METHODOLOGY/PRINCIPLE FINDINGS: We developed a computational simulation model to estimate the economic and health burden of hookworm infection in every country, WHO region, and globally, in 2016 from the societal perspective. Globally, hookworm infection resulted in …

Microfluidic Platform For Electrophysiological Recordings From Host-Stage Hookworm And Ascaris Suum Larvae: A New Tool For Anthelmintic Research, Janis Weeks, William Roberts, Kristin Robinson, Melissa Keaney, Jon Vermiere, Joseph Urban, Shawn Lockery, John M. Hawdon

Microbiology, Immunology, and Tropical Medicine Faculty Publications

The screening of candidate compounds and natural products for anthelmintic activity is important for discovering new drugs against human and animal parasites. We previously validated in Caenorhabditis elegans a microfluidic device (‘chip’) that records non-invasively the tiny electrophysiological signals generated by rhythmic contraction (pumping) of the worm's pharynx. These electropharyngeograms (EPGs) are recorded simultaneously from multiple worms per chip, providing a medium-throughput readout of muscular and neural activity that is especially useful for compounds targeting neurotransmitter receptors and ion channels. Microfluidic technologies have transformedC. elegans research and the goal of the current study was to validate hookworm andAscaris …

Changing Diagnostic Methods And Increased Detection Of Verotoxigenic Escherichia Coli, Ireland, Thomas Rice, Noreen Quinn, Roy D. Sleator, Brigid Lucey

Department of Biological Sciences Publications

The recent paradigm shift in infectious disease diagnosis from culture-based to molecular-based approaches is exemplified in the findings of a national study assessing the detection of verotoxigenic Escherichia coli infections in Ireland. The methodologic changes have been accompanied by a dramatic increase in detections of non-O157 verotoxigenic E. coli serotypes.

Clinical Utility Of Immature Platelet Fraction - An Advanced Parameter In Laboratory Hematology, Muhammad Shariq Shaikh, Sidra Asad Ali

Department of Pathology and Laboratory Medicine

No abstract provided.

Requirements For Pseudomonas Aeruginosa Type I-F Crispr-Cas Adaptation Determined Using A Biofilm Enrichment Assay, Gary E. Heussler, Jon L. Miller, Courtney E. Price, Alan J. Collins

Dartmouth Scholarship

CRISPR (clustered regularly interspaced short palindromic repeat)-Cas (CRISPR-associated protein) systems are diverse and found in many archaea and bacteria. These systems have mainly been characterized as adaptive immune systems able to protect against invading mobile genetic elements, including viruses. The first step in this protection is acquisition of spacer sequences from the invader DNA and incorporation of those sequences into the CRISPR array, termed CRISPR adaptation. Progress in understanding the mechanisms and requirements of CRISPR adaptation has largely been accomplished using overexpression of cas genes or plasmid loss assays; little work has focused on endogenous CRISPR-acquired immunity from viral predation. …

Nox2-Derived Oxidative Stress Results In Inefficacy Of Antibiotics Against Post-Influenza S. Aureus Pneumonia., Keer Sun, Vijaya Kumar Yajjala, Christopher Bauer, G. Talmon, Karl J. Fischer, Tammy Kielian, Dennis W. Metzger

Journal Articles: Pathology and Microbiology

Clinical post-influenza Staphylococcus aureus pneumonia is characterized by extensive lung inflammation associated with severe morbidity and mortality even after appropriate antibiotic treatment. In this study, we show that antibiotics rescue nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (Nox2)-deficient mice but fail to fully protect WT animals from influenza and S. aureus coinfection. Further experiments indicate that the inefficacy of antibiotics against coinfection is attributable to oxidative stress-associated inflammatory lung injury. However, Nox2-induced lung damage during coinfection was not associated with aggravated inflammatory cytokine response or cell infiltration but rather caused by reduced survival of myeloid cells. Specifically, oxidative stress increased …

Blimp-1–Mediated Cd4 T Cell Exhaustion Causes Cd8 T Cell Dysfunction During Chronic Toxoplasmosis, Sujin Hwang, Dustin A. Cobb, Rajarshi Bhadra, Ben Youngblood, Imtiaz A. Khan

Microbiology, Immunology, and Tropical Medicine Faculty Publications

CD8, but not CD4, T cells are considered critical for control of chronic toxoplasmosis. Although CD8 exhaustion has been previously reported inToxoplasma encephalitis (TE)–susceptible model, our current work demonstrates that CD4 not only become exhausted during chronic toxoplasmosis but this dysfunction is more pronounced than CD8 T cells. Exhausted CD4 population expressed elevated levels of multiple inhibitory receptors concomitant with the reduced functionality and up-regulation of Blimp-1, a transcription factor. Our data demonstrates for the first time that Blimp-1 is a critical regulator for CD4 T cell exhaustion especially in the CD4 central memory cell subset. Using a tamoxifen-dependent …

The Genetic Hierarchy Of The Heterochronic Pathway In C. Elegans, Jennifer Tsialikas

Graduate School of Biomedical Sciences Theses and Dissertations

The correct timing of developmental events is fundamental to the growth of every animal. The pathways that control developmental timing and cell-fate succession are complex and robust in a way that underscores this importance. In this work, I have shown how an early developmental regulator, LIN-14, acts to integrate the earliest aspects of development with the events that take place afterward. I have uncovered how microRNAs from two different families fit into the cascade of proteins and micro RNA regulation that defines the developmental timing pathway. Finally, my work has helped to uncover the dual-acting nature of two proteins in …

Effects Of Tcpb Mutations On Biogenesis And Function Of The Toxin-Coregulated Pilus, The Type Ivb Pilus Of Vibrio Cholerae, Yang Gao, Caitlyn A. Hauke, Jarrad M. Marles, Ronald K. Taylor

Dartmouth Scholarship

Vibrio cholerae is the etiological agent of the acute intestinal disorder cholera. The toxin-coregulated pilus (TCP), a type IVb pilus, is an essential virulence factor of V. cholerae. Recent work has shown TcpB is a large minor pilin encoded within the tcp operon. TcpB contributes to efficient pilus formation and is essential for all TCP functions. Here we have initiated a detailed, targeted mutagenesis approach to further characterize this salient TCP component. We have identified (thus far) 20 residues of TcpB, which affect either the steady state level of TcpB or alter one or more TCP functions. This study …

In Vivo Monitoring Of Therapeutic Efficacy And Virulence Profile By Bioluminescent Klebsiella Pneumoniae., Ramy Ameen Fodah

Electronic Theses and Dissertations

Klebsiella pneumoniae causes an acute respiratory infection in human with severe outcomes and high mortality rates even with antibiotic treatment. Even with its critical clinical importance, few virulence systems have been identified for K. pneumoniae limiting the development of new therapeutic strategies. Accordingly, we performed Next Generation sequencing for the strain ATCC 43816, a virulent strain in mouse respiratory disease models, and compared its genomic data with two previously sequenced strains NTUH-K2044 and MGH 78578 for the purpose of identifying genes required for colonizing host lungs. Furthermore, the virulence potential of the three K. pneumoniae strains were tested in a …

Cellular Minichromosome Maintenance Complex Component 5 (Mcm5) Is Incorporated Into Hiv-1 Virions And Modulates Viral Replication In The Newly Infected Cells., Steven Santos, Yuri Obukhov, Sergei Nekhai, Tatiana Pushkarsky, Beda Brichacek, Michael Bukrinsky, Sergey Iordanskiy

Microbiology, Immunology, and Tropical Medicine Faculty Publications

The post-entry events of HIV-1 infection occur within reverse transcription complexes derived from the viral cores entering the target cell. HIV-1 cores contain host proteins incorporated from virus-producing cells. In this report, we show that MCM5, a subunit of the hexameric minichromosome maintenance (MCM) DNA helicase complex, associates with Gag polyprotein and is incorporated into HIV-1 virions. The progeny virions depleted of MCM5 demonstrated reduced reverse transcription in newly infected cells, but integration and subsequent replication steps were not affected. Interestingly, increased packaging of MCM5 into the virions also led to reduced reverse transcription, but here viral replication was impaired. …

Inversion Of The Vδ1 To Vδ2 Γδ T Cell Ratio In Cvid Is Not Restored By Ivig And Is Associated With Immune Activation And Exhaustion., Dominic Paquin-Proulx, Nathália Silveira Barsotti, Bianca A N Santos, Ana Karolina B B Marinho, Cristina M Kokron, Karina I Carvalho, Myrthes T Barros, Jorge Kalil, Douglas F. Nixon, Esper G Kallas

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Common variable immunodeficiency (CVID) is defined by low levels of IgG and IgA, but perturbations in T cells are also commonly found. However, there is limited information on γδ T cells in CVID patients. Newly diagnosed CVID patients (n = 15) were enrolled before and after intravenous IgG (IVIg) replacement therapy. Cryopreserved peripheral blood mononuclear cells were then used to study γδ T cells and CVID patients were compared to healthy controls (n = 22). The frequency and absolute count of Vδ1 γδ T cells was found to be increased in CVID (median 0.60% vs 2.64%, P <0.01 and 7.5 vs 39, P <0.01 respectively), while they were decreased for Vδ2 γδ T cells (median, 2.36% vs 0.74%,P <0.01 and 37.8 vs 13.9, P …