Medicine and Health Sciences Commons^™

Immunogenicity And Protective Efficacy Of The Dar-901 Booster Vaccine In A Murine Model Of Tuberculosis, Timothy Lahey, Dominick Laddy, Krystal Hill, Jacqueline Schaeffer

Dartmouth Scholarship

The development of a novel tuberculosis vaccine is a leading global health priority. SRL172, an inactivated, whole-cell mycobacterial vaccine, was safe, immunogenic and reduced the incidence of culture-confirmed tuberculosis in a phase III trial in HIV-infected and BCG immunized adults in Tanzania. Here we describe the immunogenicity and protective efficacy of DAR-901, a booster vaccine against tuberculosis manufactured from the same seed strain using a new scalable method.

Pyrimidine Pathway-Dependent And -Independent Functions Of The Toxoplasma Gondii Mitochondrial Dihydroorotate Dehydrogenase, Miryam Andrea Hortua Triana, Daniela Cajiao Herrera, Barbara H. Zimmermann, Barbara A. Fox, David Bzik

Dartmouth Scholarship

Dihydroorotate dehydrogenase (DHODH) mediates the fourth step of de novo pyrimidine biosynthesis and is a proven drug target for inducing immunosuppression in therapy of human disease as well as a rapidly emerging drug target for treatment of malaria. In Toxoplasma gondii, disruption of the first, fifth, or sixth step of de novo pyrimidine biosynthesis induced uracil aux- otrophy. However, previous attempts to generate uracil auxotrophy by genetically deleting the mitochondrion-associated DHODH of T. gondii (Tg DHODH) failed. To further address the essentiality of Tg DHODH, mutant gene alleles deficient in Tg DHODH activity were designed to ablate the enzyme activity. …

Use Of A Multiplex Transcript Method For Analysis Of Pseudomonas Aeruginosa Gene Expression Profiles In The Cystic Fibrosis Lung, Alex H. Gifford, Sven D. Willger, Emily L. Dolben, Lisa A. Moulton, Dana Dorman, Heather Bean, Jane Hill, Thomas Hampton, Alix Ashare, Deborah Hogan

Dartmouth Scholarship

The discovery of therapies that modulate Pseudomonas aeruginosa virulence or that can eradicate chronic P. aeruginosa lung infections associated with cystic fibrosis (CF) will be advanced by an improved understanding of P. aeruginosa behavior in vivo We demonstrate the use of multiplexed Nanostring technology to monitor relative abundances of P. aeruginosa transcripts across clinical isolates, in serial samples, and for the purposes of comparing microbial physiology in vitro and in vivo The expression of 75 transcripts encoded by genes implicated in CF lung disease was measured in a variety of P. aeruginosa strains as well as RNA serial sputum samples …

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 …

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 …

Cyclic Di-Gmp-Regulated Periplasmic Proteolysis Of A Pseudomonas Aeruginosa Type Vb Secretion System Substrate, Richard B. Cooley, T. Jarrod Smith, Wilfred Leung, Valerie Tierney, Bradley Borlee, George A. O'Toole, Holger Sondermann

Dartmouth Scholarship

We previously identified a second-messenger-regulated signaling system in the environmental bacterium Pseudomonas fluorescens which controls biofilm formation in response to levels of environmental inorganic phosphate. This system contains the transmembrane cyclic di-GMP (c-di-GMP) receptor LapD and the periplasmic protease LapG. LapD regulates LapG and controls the ability of this protease to process a large cell surface adhesin protein, LapA. While LapDG orthologs can be identified in diverse

The Pseudomonas Aeruginosa Efflux Pump Mexghi-Opmd Transports A Natural Phenazine That Controls Gene Expression And Biofilm Development, Hassan Sakhtah, Leslie Koyama, Yihan Zhang, Diana K. Morales, Blanche Fields, Alexa Price-Whelan, Deborah Hogan

Dartmouth Scholarship

Redox-cycling compounds, including endogenously produced phenazine antibiotics, induce expression of the efflux pump MexGHI-OpmD in the opportunistic pathogen Pseudomonas aeruginosa Previous studies of P. aeruginosa virulence, physiology, and biofilm development have focused on the blue phenazine pyocyanin and the yellow phenazine-1-carboxylic acid (PCA). In P. aeruginosa phenazine biosynthesis, conversion of PCA to pyocyanin is presumed to proceed through the intermediate 5-methylphenazine-1-carboxylate (5-Me-PCA), a reactive compound that has eluded detection in most laboratory samples. Here, we apply electrochemical methods to directly detect 5-Me-PCA and find that it is transported by MexGHI-OpmD in P. aeruginosa strain PA14 planktonic and biofilm cells. We …

Expression Of Complement And Toll-Like Receptor Pathway Genes Is Associated With Malaria Severity In Mali: A Pilot Case Control Study, Rafal S. Sobota, Antoine Dara, Jessica E. Manning, Amadou Niangaly

Dartmouth Scholarship

Background: The host response to infection by Plasmodium falciparum, the parasite most often responsible for severe malaria, ranges from asymptomatic parasitaemia to death. The clinical trajectory of malaria is influenced by host genetics and parasite load, but the factors determining why some infections produce uncomplicated malaria and some proceed to severe disease remain incompletely understood.

Methods: To identify molecular markers of severe falciparum malaria, human gene expression patterns were compared between children aged 6 months to 5 years with severe and uncomplicated malaria who were enrolled in a case–control study in Bandiagara, Mali. Microarrays were used to obtain expression …

The Gras Sensor In Staphylococcus Aureus Mediates Resistance To Host Defense Peptides Differing In Mechanisms Of Action, Siyang Chaili, Ambrose L. L. Cheung, Arnold S. Bayer, Yan Q. Xiong, Alan Waring, Guido Memmi, Niles Donegan

Dartmouth Scholarship

Staphylococcus aureus uses the two-component regulatory system GraRS to sense and respond to host defense peptides (HDPs). However, the mechanistic impact of GraS or its extracellular sensing loop (EL) on HDP resistance is essentially unexplored. Strains with null mutations in the GraS holoprotein (ΔgraS) or its EL (ΔEL) were compared for mechanisms of resistance to HDPs of relevant immune sources: neutrophil α-defensin (human neutrophil peptide 1 [hNP-1]), cutaneous β-defensin (human β-defensin 2 [hBD-2]), or the platelet kinocidin congener RP-1. Actions studied by flow cytometry included energetics (ENR); membrane permeabilization (PRM); annexin V binding (ANX), and cell death protease activation (CDP). …

Patterns Of Human Herpesvirus-8 Oral Shedding Among Diverse Cohorts Of Human Herpesvirus-8 Seropositive Persons, Rachel A. Bender Ignacio, Jason D. Goldman, Amalia S. Magaret, Stacy Selke, Meei-Li Huang, Soren Gantt, Christine Johnston, Warren Phipps, Joshua Schiffer, Richard Zuckerman

Dartmouth Scholarship

Human herpesvirus-8 (HHV-8), the etiologic agent of Kaposi sarcoma (KS), establishes lifelong latent infection with periodic lytic replication (“shedding”) at mucosal sites, especially the oropharynx. Patterns of HHV-8 shedding are not well understood, and require elucidation to better predict risk of HHV-8 related malignancies in those infected. We sought to characterize patterns of HHV-8 oropharyngeal shedding among diverse cohorts that enrolled HHV-8 seropositive persons.