Medical Microbiology Commons^™

Novel Approaches Reveal That Toxoplasma Gondii Bradyzoites Within Tissue Cysts Are Dynamic And Replicating Entities In Vivo, Elizabeth Watts, Yihua Zhao, Animesh Dhara, Becca Eller, Abhijit R. Patwardhan, Anthony P. Sinai

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Despite their critical role in chronic toxoplasmosis, the biology of Toxoplasma gondii bradyzoites is poorly understood. In an attempt to address this gap, we optimized approaches to purify tissue cysts and analyzed the replicative potential of bradyzoites within these cysts. In order to quantify individual bradyzoites within tissue cysts, we have developed imaging software, BradyCount 1.0, that allows the rapid establishment of bradyzoite burdens within imaged optical sections of purified tissue cysts. While in general larger tissue cysts contain more bradyzoites, their relative "occupancy" was typically lower than that of smaller cysts, resulting in a lower packing density. The packing …

Challenges And Opportunities For T Cell-Mediated Strategies To Eliminate Hiv Reservoirs, Mark A. Brockman, R. Brad Jones, Zabrina L. Brumme

Microbiology, Immunology, and Tropical Medicine Faculty Publications

HIV’s ability to establish latent reservoirs of reactivation-competent virus is the major barrier to cure. “Shock and kill” methods consisting of latency reversing agents (LRAs) followed by elimination of reactivating cells through cytopathic effects are under active development. However, the clinical efficacy of LRAs remains to be established. Moreover, recent studies indicate that reservoirs may not be reduced efficiently by either viral cytopathic or CD8+ T-cell-mediated mechanisms. In this perspective, we highlight challenges to T-cell-mediated elimination of HIV reservoirs, including characteristics of responding T-cells, aspects of the cellular reservoirs and properties of the latent virus itself. We also discuss potential …

Jan Van Der Noordaa (1934-2015); A Virologist Pur Sang., Ben Berkhout, Michael Bukrinsky

Microbiology, Immunology, and Tropical Medicine Faculty Publications

No abstract provided.

Method And System For Diagnosis Of Lawsonia Intracellularis, Harold F. Stills Jr., David W. Horohov, Allen E. Page

Microbiology, Immunology and Molecular Genetics Faculty Patents

A method, system, and kit are provided for diagnosing L. intracellularis infection or exposure in a subject. The method includes purifying whole L. intracellularis from host cells and host debris produced in or on a suitable medium and adhering the purified whole L. intracellularis on a suitable material to form an antigen substrate for determining whether a subject produces L. intracellularis-specific antibodies against the antigen to thereby indicate L. intracellularis exposure or infection in the subject. The kit includes purified whole L. intracellularis produced from host cells and host debris adhered to a suitable material to form an antigen …

Borrelia Burgdorferi Reva Significantly Affects Pathogenicity And Host Response In The Mouse Model Of Lyme Disease, Rebecca Byram, Robert A. Gaultney, Angela M. Floden, Christopher Hellekson, Brandee L. Stone, Amy Bowman, Brian Stevenson, Barbara J. B. Johnson, Catherine A. Brissette

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The Lyme disease spirochete, Borrelia burgdorferi, expresses RevA and numerous outer surface lipoproteins during mammalian infection. As an adhesin that promotes bacterial interaction with fibronectin, RevA is poised to interact with the extracellular matrix of the host. To further define the role(s) of RevA during mammalian infection, we created a mutant that is unable to produce RevA. The mutant was still infectious to mice, although it was significantly less well able to infect cardiac tissues. Complementation of the mutant with a wild-type revA gene restored heart infectivity to wild-type levels. Additionally, revA mutants led to increased evidence of arthritis, …

Identifying The Critical Domain Of Ll-37 Involved In Mediating Neutrophil Activation In The Presence Of Influenza Virus: Functional And Structural Analysis., Shweta Tripathi, Guangshun Wang, Mitchell White, Michael Rynkiewicz, Barbara Seaton, Kevan Hartshorn

Journal Articles: Pathology and Microbiology

The human cathelicidin LL-37 has been shown to play a role in host defense against influenza A viruses (IAV) through direct antiviral effects and through modulating inflammatory responses to infection. We recently showed that LL-37 increases neutrophil respiratory burst and neutrophil extracellular trap (NET) responses to IAV through engaging formyl peptide receptor 2 (FPR-2). In this paper we show that a fragment of LL-37, GI-20, which is composed of the central helical segment of the peptide, has similar effects as LL-37 on neutrophil activation. In addition to increasing respiratory burst and NET responses of the cells to IAV through an …

Role Of The Dna Sensor Sting In Protection From Lethal Infection Following Corneal And Intracerebral Challenge With Herpes Simplex Virus 1, Zachary M. Parker, Aisling A. Murphy, David. A. Leib

Dartmouth Scholarship

STING is a protein in the cytosolic DNA and cyclic dinucleotide sensor pathway that is critical for the initiation of innate responses to infection by various pathogens. Consistent with this, herpes simplex virus 1 (HSV-1) causes invariable and rapid lethality in STING-deficient (STING(-/-)) mice following intravenous (i.v.) infection. In this study, using real-time bioluminescence imaging and virological assays, as expected, we demonstrated that STING(-/-) mice support greater replication and spread in ocular tissues and the nervous system. In contrast, they did not succumb to challenge via the corneal route even with high titers of a virus that was routinely lethal …

Staphylococcus Aureus Biofilms Induce Macrophage Dysfunction Through Leukocidin Ab And Alpha-Toxin., Tyler D. Scherr, Mark L. Hanke, Ouwen Huang, David B.A. James, Alexander R. Horswill, Kenneth W. Bayles, Paul D. Fey, Victor J. Torres, Tammy Kielian

Journal Articles: Pathology and Microbiology

UNLABELLED: The macrophage response to planktonic Staphylococcus aureus involves the induction of proinflammatory microbicidal activity. However, S. aureus biofilms can interfere with these responses in part by polarizing macrophages toward an anti-inflammatory profibrotic phenotype. Here we demonstrate that conditioned medium from mature S. aureus biofilms inhibited macrophage phagocytosis and induced cytotoxicity, suggesting the involvement of a secreted factor(s). Iterative testing found the active factor(s) to be proteinaceous and partially agr-dependent. Quantitative mass spectrometry identified alpha-toxin (Hla) and leukocidin AB (LukAB) as critical molecules secreted by S. aureus biofilms that inhibit murine macrophage phagocytosis and promote cytotoxicity. A role for Hla …

Application Of Β-Lactamase Reporter Fusions As An Indicator Of Effector Protein Secretion During Infections With The Obligate Intracellular Pathogen Chlamydia Trachomatis , Konrad E. Mueller, Kenneth A. Fields

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Chlamydia spp. utilize multiple secretion systems, including the type III secretion system (T3SS), to deploy host-interactive effector proteins into infected host cells. Elucidation of secreted proteins has traditionally required ectopic expression in a surrogate T3SS followed by immunolocalization of endogenous candidate effectors to confirm secretion by chlamydiae. The ability to transform Chlamydia and achieve stable expression of recombinant gene products has enabled a more direct assessment of secretion. We adapted TEM-1 β-lactamase as a reporter system for assessment of chlamydial protein secretion. We provide evidence that this system facilitates visualization of secretion in the context of infection. Specifically, our findings …

The Right Tool For The Job: Detection Of Soil-Transmitted Helminths In Areas Co-Endemic For Other Helminths, Maria V. Periago, Renata C. Diniz, Simone A. Pinto, Anna Yakovleva, Rodrigo Correa-Oliveira, David J. Diemert, Jeffrey M. Bethony

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Due to the recent increased use of the McMaster (MM) fecal egg counting method for assessing benzimidazole drug efficacy for treating soil-transmitted helminth (STH) infections, the aim of the current study was to determine the operational value of including the MM method alongside the Kato-Katz (KK) fecal thick smear to increase the diagnostic sensitivity when STHs are co-endemic with trematode helminths (e.g., Schistosoma mansoni).

Methods

A cross-sectional study was conducted in school-aged children aged 4-18 years in the northeastern region of the State of Minas Gerais (Brazil), where Necator americanus, Ascaris lumbricoides, Trichuris trichiura, and S …

Intracellular Listeria Monocytogenes Comprises A Minimal But Vital Fraction Of The Intestinal Burden Following Foodborne Infection, Grant S. Jones, Kate M. Bussell, Tanya Myers-Morales, Abigail M. Fieldhouse, Elsa N. Bou Ghanem, Sarah E. F. D'Orazio

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Listeria monocytogenes is a highly adaptive bacterium that replicates as a free-living saprophyte in the environment as well as a facultative intracellular pathogen that causes invasive foodborne infections. The intracellular life cycle of L. monocytogenes is considered to be its primary virulence determinant during mammalian infection; however, the proportion of L. monocytogenes that is intracellular in vivo has not been studied extensively. In this report, we demonstrate that the majority of wild-type (strain EGDe) and mouse-adapted (InlA^m-expressing) L. monocytogenes recovered from the mesenteric lymph nodes (MLN) was extracellular within the first few days after foodborne infection. In addition, …

Correlation Of Periodontal Pathogens In Concurrent Endodontic-Periodontal Diseases, Amela Lačević, Federico Foschi, Lejla Pojskić, Naris Pojskić, Kasim Bajrović, Jacques Izard

Department of Food Science and Technology: Faculty Publications

Objectives: This study investigated the correlation between Tannerella forsythia, Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans at dual sites in concurrent endodonticperiodontal diseases.

Material and methods: Samples were collected from endodontium and periodontium in cases of concurrent endodontic-periodontal diseases from thirty participants. The sensitivity and specificity of SYBR Green real-time PCR was used to identify the targeted species. Absolute number of targeted genome copies in tested samples were extrapolated from respective calibration curve.

Results: No statistical difference was found in the number of detected endodontic-periodontal pathogens between the endodontium and periodontium. The Pearson test …

Zbtb20 Is A Sequence-Specific Transcriptional Repressor Of Alpha-Fetoprotein Gene, Hai Zhang, Dongmei Cao, Luting Zhou, Ye Zhang, Xiaoqin Guo, Hui Li, Yuxia Chen, Brett T. Spear, Jia-Wei Wu, Zhifang Xie, Weiping J Zhang

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Alpha-fetoprotein (AFP) represents a classical model system to study developmental gene regulation in mammalian cells. We previously reported that liver ZBTB20 is developmentally regulated and plays a central role in AFP postnatal repression. Here we show that ZBTB20 is a sequence-specific transcriptional repressor of AFP. By ELISA-based DNA-protein binding assay and conventional gel shift assay, we successfully identified a ZBTB20-binding site at -104/-86 of mouse AFP gene, flanked by two HNF1 sites and two C/EBP sites in the proximal promoter. Importantly, mutation of the core sequence in this site fully abolished its binding to ZBTB20 in vitro, as well …

Selective Involvement Of The Checkpoint Regulator Vista In Suppression Of B-Cell, But Not T-Cell, Responsiveness By Monocytic Myeloid-Derived Suppressor Cells From Mice Infected With An Immunodeficiency-Causing Retrovirus, Kathy A. Green, Li Wang, Randolph J. Noelle, William R. Green

Dartmouth Scholarship

Inhibition of T-cell responses in tumor microenvironments by myeloid-derived suppressor cells (MDSCs) is widely accepted. We demonstrated augmentation of monocytic MDSCs whose suppression of not only T-cell, but also B-cell, responsiveness paralleled the immunodeficiency during LP-BM5 retrovirus infection. MDSCs inhibited T cells by inducible nitric oxide synthase (iNOS)/nitric oxide (NO), but uniquely, inhibition of B cells was ~50% dependent each on iNOS/NO and the MDSC-expressed negative-checkpoint regulator VISTA. Blockade with a combination of iNOS/NO and VISTA caused additive or synergistic abrogation of MDSC-mediated suppression of B-cell responsiveness.

A Self-Lysis Pathway That Enhances The Virulence Of A Pathogenic Bacterium, Kirsty A. Mcfarland, Emily L. Dolben, Michele Leroux, Tracy K. Kambara, Kathryn Ramsey, Robin Kirkpatrick, Joseph Mougous, Deborah Hogan, Simon Dove

Dartmouth Scholarship

In mammalian cells, programmed cell death (PCD) plays important roles in development, in the removal of damaged cells, and in fighting bacterial infections. Although widespread among multicellular organisms, there are relatively few documented instances of PCD in bacteria. Here we describe a potential PCD pathway in Pseudomonas aeruginosa that enhances the ability of the bacterium to cause disease in a lung infection model. Activation of the system can occur in a subset of cells in response to DNA damage through cleavage of an essential transcription regulator we call AlpR. Cleavage of AlpR triggers a cell lysis program through de-repression of …

Ceramides Promote Apoptosis For Virus-Infected Lymphoma Cells Through Induction Of Ceramide Synthases And Viral Lytic Gene Expression, Lu Dai, Jimena Trillo-Tinoco, Aiping Bai, Yihan Chen, Jacek Bielawski, Luis Del Valle, Charles D. Smith, Augusto C. Ochoa, Zhiqiang Qin, Chris Parsons

School of Medicine Faculty Publications

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent for several human cancers including primary effusion lymphoma (PEL), a rapidly progressive malignancy arising preferentially in immunocompromised patients. With conventional chemotherapy, PEL continues to portend high mortality, dictating the development of novel therapeutic strategies. Sphingosine kinase 2 (SphK2) represents a key gatekeeper for sphingolipid metabolism, responsible for conversion of ceramides to sphingosine-1-phosphate (S1P). We have previously demonstrated that targeting SphK2 using a novel selective inhibitor, ABC294640, leads to intracellular accumulation of ceramides and induces apoptosis for KSHV-infected PEL cells, while suppressing tumor progression in vivo. In the current study, we sought to …

Levels Of 8-Oxodg Predict Hepatobiliary Pathology In Opisthorchis Viverrini Endemic Settings In Thailand., Prasert Saichua, Anna Yakovleva, Christine Kamamia, Amar R. Jariwala, Paul J. Brindley, Jeffrey M. Bethony, + 8 More

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Opisthorchis viverrini is distinct among helminth infections as it drives a chronic inflammatory response in the intrahepatic bile duct that progresses from advanced periductal fibrosis (APF) to cholangiocarcinoma (CCA). Extensive research shows that oxidative stress (OS) plays a critical role in the transition from chronic O. viverrini infection to CCA. OS also results in the excision of a modified DNA lesion (8-oxodG) into urine, the levels of which can be detected by immunoassay. Herein, we measured concentrations of urine 8-oxodG by immunoassay from the following four groups in the Khon Kaen Cancer Cohort study: (1) O. viverrini negative individuals, (2) …

Irreversible Dual Inhibitory Mode: The Novel Btk Inhibitor Pls-123 Demonstrates Promising Anti-Tumor Activity In Human B-Cell Lymphoma., Ning Ding, Xitao Li, Yunfei Shi, Lingyan Ping, Lina Wu, Kai Fu, Lixia Feng, Xiaohui Zheng, Yuqin Song, Zhengying Pan, Jun Zhu

Journal Articles: Pathology and Microbiology

The B-cell receptor (BCR) signaling pathway has gained significant attention as a therapeutic target in B-cell malignancies. Recently, several drugs that target the BCR signaling pathway, especially the Btk inhibitor ibrutinib, have demonstrated notable therapeutic effects in relapsed/refractory patients, which indicates that pharmacological inhibition of BCR pathway holds promise in B-cell lymphoma treatment. Here we present a novel covalent irreversible Btk inhibitor PLS-123 with more potent anti-proliferative activity compared with ibrutinib in multiple cellular and in vivo models through effective apoptosis induction and dual-action inhibitory mode of Btk activation. The phosphorylation of BCR downstream activating AKT/mTOR and MAPK signal pathways …

Links Between Anr And Quorum Sensing In Pseudomonas Aeruginosa Biofilms, John H. Hammond, Emily F. Dolben, T. Jarrod Smith, Sabin Bhuju, Deborah Hogan

Dartmouth Scholarship

In Pseudomonas aeruginosa, the transcription factor Anr controls the cellular response to low oxygen or anoxia. Anr activity is high in oxygen-limited environments, including biofilms and populations associated with chronic infections, and Anr is necessary for persistence in a model of pulmonary infection. In this study, we characterized the Anr regulon in biofilm-grown cells at 1% oxygen in the laboratory strain PAO1 and in a quorum sensing (QS)-deficient clinical isolate, J215. As expected, transcripts related to denitrification, arginine fermentation, high-affinity cytochrome oxidases, and CupA fimbriae were lower in the Δanr derivatives. In addition, we observed that transcripts associated with quorum …

Molecular Mechanisms That Govern Human Cardiac Stem Cell Age Disparity, Tania Fuentes

Loma Linda University Electronic Theses, Dissertations & Projects

Transplantation of adult endogenous cardiovascular progenitor cells for heart repair results in some clinical benefit, however these stem cells lack the regenerative capacity unique to neonatal cardiovascular stem cells. The goal of this work was to identify mechanisms that contribute to the decline of cardiac stem cell regenerative ability with age and investigate novel therapeutic strategies to improve cardiac stem cell function. When comparing neonatal and adult cardiovascular stem cell clones, both cell types were capable of cardiomyogenic differentiation. However, the expression levels of forty-one microRNAs were significantly altered with age. Expression differences were correlated with reduced proliferation and a …

Antibacterial Evaluation Of Polygonum Multiflorum, Andy S. Demianicz

Seton Hall University Dissertations and Theses (ETDs)

Polygonum multiflorum, commonly known as Chinese Knotweed, is a tonic herb primarily used to enhance bodily functions. Recently, it has been shown to contain strong antioxidant, antibacterial and antiviral activity. The extract from the roots of Chinese Knotweed was used to assess its antibacterial properties against a broad spectrum of bacterial species, including 5 Gram-positive (B. cereus, B. megaterium, S. epidermidis, S. mutans and S. pyogenes) and 4 Gram-negative (E. aerogenes, E. coli, P. vulgaris and P. aeruginosa). Microtiter assays were carried out to evaluate the antibacterial activity of Chinese Knotweed at 0.5%, 1%, 1.5% and 2.5% concentrations in order …

Effect Of Chinese Knotweed Extract On Hsv-1 Infection Of Vero Cells, Derek J. Prince

Seton Hall University Dissertations and Theses (ETDs)

HSV-1 is an opportunistic virus responsible for infecting the majority of the global population. The ability of this virus to strategically alternate between lytic and latent states has made the development of effective treatments challenging. Polygonum multiflorum (Chinese Knotweed, CK) is a perennial plant local to the south central regions of China. The thunb (root) constituents of this compound have been used in traditional Chinese medicines to treat a broad range of illnesses for centuries. In the present study, CK root extracts were evaluated for potential anti-HSV-1 activity. Cytopathic effect (CPE) monitoring studies indicate that Vero cells infected with HSV-1 …

Clustered Regularly Interspaced Short Palindromic Repeat-Dependent, Biofilm-Specific Death Of Pseudomonas Aeruginosa Mediated By Increased Expression Of Phage-Related Genes, Gary E. E. Heussler, Kyle C. Cady, Katja Koeppen, Sabin Bhuju, Bruce A. Stanton, George A. O’Toole

Dartmouth Scholarship

The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (CRISPR/Cas) system is an adaptive immune system present in many archaea and bacteria. CRISPR/Cas systems are incredibly diverse, and there is increasing evidence of CRISPR/Cas systems playing a role in cellular functions distinct from phage immunity. Previously, our laboratory reported one such alternate function in which the type 1-F CRISPR/Cas system of the opportunistic pathogen Pseudomonas aeruginosa strain UCBPP-PA14 (abbreviated as P. aeruginosa PA14) inhibits both biofilm formation and swarming motility when the bacterium is lysogenized by the bacteriophage DMS3. In this study, we demonstrated that the presence of just the DMS3 …

Tonb Not Directly Related To Efflux Of Antibiotics In E. Coli, Amber Gombash

Honors Projects

Studies in Pseudomonas aeruginosa have suggested that the TonB energy transduction system directly contributes to efflux-mediated antibiotic resistance, ostensibly by energizing one or more efflux systems. We have found ∆tonB strains of Escherichia coli to similarly be more sensitive to certain antibiotics relative to wild-type strains. To test the hypothesis that this enhanced sensitivity involved the energization of efflux systems, sensitivity patterns for a variety of antibiotics were evaluated using a set of strains differentially lacking genes encoding the Acr efflux system, the universal outer membrane efflux portal TolC, and TonB. No correlation was evident between the resistance phenotypes of …

Identification Of Transcription Factors Gzf3, Rfx1, Orf19.3928 As Being Implicated In Candida-Bacterial Interactions., Joni Watson

Undergraduate Honors Theses

Candida albicans is an opportunistic pathogen that is present in the normal flora in a majority of individuals. One key factor in C. albicans virulence is the ability to change its morphology from yeast to an elongated or hyphal form. The regulation of this morphogenesis relies in part upon quorum sensing (QS) molecules. C. albicans often exists as part of a mixed culture alongside other microbes and is influenced by their presence as well as the presence of QS molecules that they produce. In this study, a library of diploid homozygous transcriptional regulator knockout (TRKO) mutants were screened to identify …

Nonreplicating, Cyst-Defective Type Ii Toxoplasma Gondii Vaccine Strains Stimulate Protective Immunity Against Acute And Chronic Infection, Barbara Andrea Fox, David J. Bzik

Dartmouth Scholarship

Live attenuated vaccine strains, such as type I nonreplicating uracil auxotroph mutants, are highly effective in eliciting lifelong immunity to virulent acute infection by Toxoplasma gondii. However, it is currently unknown whether vaccine-elicited immunity can provide protection against acute infection and also prevent chronic infection. To address this problem, we developed nonreverting, nonreplicating, live attenuated uracil auxotroph vaccine strains in the type II Δku80 genetic background by targeting the deletion of the orotidine 5′-monophosphate decarboxylase (OMPDC) and uridine phosphorylase (UP) genes. Deletion of OMPDC induced a severe uracil auxotrophy with loss of replication, loss of …

Manipulation Of The Microbiome And Its Impact On Functional Recovery Following Ischemic Stroke, Michal Jandzinski

Honors Scholar Theses

Each year, nearly 800,000 individuals residing in the United States will have a stroke. Of these, about 130,000 cases will prove fatal while many of the survivors will be forced to live with disability for the remainder of their lives. Out of all strokes over 87% are ischemic strokes. The widespread incidence of this debilitating condition costs the United States an estimated $36.5 billion dollars every single year. Despite this, clinicians are armed with very little to combat the disease. Recent research developments have brought about the rise in awareness about the importance of the microbiome, the various gut flora …

Loss Of Cbl And Cbl-B Ubiquitin Ligases Abrogates Hematopoietic Stem Cell Quiescence And Sensitizes Leukemic Disease To Chemotherapy., Wei An, Scott A. Nadeau, Bhopal C. Mohapatra, Dan Feng, Neha Zutshi, Matthew D. Storck, Priyanka Arya, James E. Talmadge, Jane L. Meza, Vimla Band, Hamid Band

Journal Articles: Pathology and Microbiology

Cbl and Cbl-b are tyrosine kinase-directed RING finger type ubiquitin ligases (E3s) that negatively regulate cellular activation pathways. E3 activity-disrupting human Cbl mutations are associated with myeloproliferative disorders (MPD) that are reproduced in mice with Cbl RING finger mutant knock-in or hematopoietic Cbl and Cbl-b double knockout. However, the role of Cbl proteins in hematopoietic stem cell (HSC) homeostasis, especially in the context of MPD is unclear. Here we demonstrate that HSC expansion and MPD development upon combined Cbl and Cbl-b deletion are dependent on HSCs. Cell cycle analysis demonstrated that DKO HSCs exhibit reduced quiescence associated with compromised reconstitution …

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. …

Antiviral Activity Of The Human Cathelicidin, Ll-37, And Derived Peptides On Seasonal And Pandemic Influenza A Viruses., Shweta Tripathi, Guangshun Wang, Mitchell White, Li Qi, Jeffery Taubenberger, Kevan L. Hartshorn

Journal Articles: Pathology and Microbiology

Human LL-37, a cationic antimicrobial peptide, was recently shown to have antiviral activity against influenza A virus (IAV) strains in vitro and in vivo. In this study we compared the anti-influenza activity of LL-37 with that of several fragments derived from LL-37. We first tested the peptides against a seasonal H3N2 strain and the mouse adapted H1N1 strain, PR-8. The N-terminal fragment, LL-23, had slight neutralizing activity against these strains. In LL-23V9 serine 9 is substituted by valine creating a continuous hydrophobic surface. LL-23V9 has been shown to have increased anti-bacterial activity compared to LL-23 and we now show slightly …