Medical Microbiology Commons^™

Expression Of Mucoid Induction Factor Muce Is Dependent Upon The Alternate Sigma Factor Algu In Pseudomonas Aeruginosa, Yeshi Yin, F. Heath Damron, T. Ryan Withers, Christopher L. Prichett, Xin Wang, Michael J. Schurr, Hongwei Yu

Biochemistry and Microbiology

Background

Alginate overproduction in P. aeruginosa, also referred to as mucoidy, is a poor prognostic marker for patients with cystic fibrosis (CF). We previously reported the construction of a unique mucoid strain which overexpresses a small envelope protein MucE leading to activation of the protease AlgW. AlgW then degrades the anti-sigma factor MucA thus releasing the alternative sigma factor AlgU/T (σ²²) to initiate transcription of the alginate biosynthetic operon.

Results

In the current study, we mapped the mucE transcriptional start site, and determined that P_mucE activity was dependent on AlgU. Additionally, the presence of triclosan and …

Recruitment Of Tlr Adapter Trif To Tlr4 Signaling Complex Is Mediated By The Second Helical Region Of Trif Tir Domain, Wenji Piao, Lisa W. Ru, Kurt H. Piepenbrink, Eric J. Sundberg, Stefanie N. Vogel, Vladimir Y. Toshchakov

Food for Health: Publications

Toll/IL-1R resistance (TIR) domain–containing adapter-inducing IFN-β (TRIF) is a Toll-like receptor (TLR) adapter that mediates MyD88-independent induction of type I interferons through activation of IFN regulatory factor 3 and NFκB. We have examined peptides derived from the TRIF TIR domain for ability to inhibit TLR4. In addition to a previously identified BB loop peptide (TF4), a peptide derived from putative helix B of TRIF TIR (TF5) strongly inhibits LPS-induced cytokine and MAPK activation in wild-type cells. TF5 failed to inhibit LPS-induced cytokine and kinase activation in TRIF-deficient immortalized bone-marrow–derived macrophage, but was fully inhibitory in MyD88 knockout cells. TF5 does …

Mycological Study For A Management Plan Of A Neotropical Show Cave (Brazil), Erika Linzi Silva Taylor, Maria Aparecida De Resende Stoianoff, Rodrigo Lopes Ferreira

International Journal of Speleology

Caves are stable environments with characteristics favoring the development of microorganisms. The allocthonous input of organic matter and microbes into the warm Neotropical caves may favor the development of filamentous fungi, including pathogenic species. Histoplasma capsulatum is a pathogenic species commonly found in caves and associated with bat and bird guano. Many Brazilian caves have been historically visited due to scenic and religious tourism. The objective of this study was to perform a microbiology study for a management plan of a show cave in Brazil, focusing on the presence and distribution of pathogenic and opportunistic fungi in the cave. Statistics …

Role Of Vimf In Gingipain Maturation In Porphyromonas Gingivalis, Arun S. Muthiah

Loma Linda University Electronic Theses, Dissertations & Projects

Gingipain activity in Porphyromonas gingivalis, the major etiological agent in adult periodontitis, is post-translationally regulated by unique Vim proteins including VimF, a putative glycosyltransferase. To ascertain the VimF mediated phenotype we first inactivated the vimF gene in P. gingivalis ATCC 33277 (FLL476), a less virulent fimbriated strain. We observed that the vimF-defective mutant (FLL476) showed a phenotype similar to that of the vimF-defective mutant (FLL95) in the P. gingivalis W83 background. While hemagglutination was not detected and autoaggregationn was reduced, biofilm formation was increased in FLL476. Also, invasive capacity decreased for this mutant. Furthermore, fimbrial structures were missing in FLL476, …

A Dysfunctional Tricarboxylic Acid Cycle Enhances Fitness Of Staphylococcus Epidermidis During Β-Lactam Stress., Vinai Chittezham Thomas, Lauren C. Kinkead, Ashley Janssen, Carolyn R. Schaeffer, Keith M. Woods, Jill K. Lindgren, Jonathan M. Peaster, Sujata S. Chaudhari, Marat Sadykov, Joselyn Jones, Sameh M. Mohamadi Abdelghani, Matthew C. Zimmerman, Kenneth W. Bayles, Greg A. Somerville, Paul D. Fey

Journal Articles: Pathology and Microbiology

A recent controversial hypothesis suggested that the bactericidal action of antibiotics is due to the generation of endogenous reactive oxygen species (ROS), a process requiring the citric acid cycle (tricarboxylic acid [TCA] cycle). To test this hypothesis, we assessed the ability of oxacillin to induce ROS production and cell death in Staphylococcus epidermidis strain 1457 and an isogenic citric acid cycle mutant. Our results confirm a contributory role for TCA-dependent ROS in enhancing susceptibility of S. epidermidis toward β-lactam antibiotics and also revealed a propensity for clinical isolates to accumulate TCA cycle dysfunctions presumably as a way to tolerate these …

Fecal Transplantation Does Not Transfer Either Susceptibility Or Resistance To Food Borne Listeriosis In C57bl/6 And Balb/C/By Mice, Tanya Myers-Morales, Kate M. Bussell, Sarah E. F. D'Orazio

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The composition of the intestinal microbiota has wide reaching effects on the health of an individual, including the development of protective innate immune responses. In this report, a fecal transplantation approach was used to determine whether resistance to food borne listeriosis was dependent on the murine gut microbiota. Transplantation of BALB/c/By feces did not increase the susceptibility of C57BL/6 mice to Listeria monocytogenes infection. Likewise, transplantation of C57BL/6 fecal matter did not enhance the resistance of BALB/c/By mice. Thus, intestinal microbiota composition is not a key factor that confers either susceptibility or resistance to food borne listeriosis in mice.

Extrauterine Listeriosis In The Gravid Mouse Influences Embryonic Growth And Development, M. M. Suyemoto, T. S. Hamrick, P. A. Spears, J. R. Horton, I. M. Washington, E. A. Havell, L. B. Borst, P. E. Orndorff

Osteopathic Medicine, Jerry M. Wallace School of

No abstract provided.

Regulating Rsma Expression In Pseudomonas Aeruginosa, Sean D. Stacey

Electronic Theses and Dissertations

Pseudomonas aeruginosa, a Gram-negative bacillus, commonly infects immunocompromised individuals and uses a variety of virulence factors to persist in these hosts. The posttranscriptional regulator, RsmA, plays a role in the expression of many virulence factors in P. aeruginosa. RsmA up regulates virulence factors used in colonizing hosts. However, regulation of rsmA is not well elucidated. Transposon mutagenesis was performed on P. aeruginosa containing a transcriptional rsmA-lacZ fusion to answer this question. Mutants were screened via β-galactosidase assay and transposon insertions identified via arbitrary PCR. A probable MFS transporter, we named mtpX, was one significant transposon mutant identified. …

The Involvement Of Beta-Catenin In The Inflammatory Response Leading To Autoimmune Diabetes Development., Arin Lee Zirnheld

Electronic Theses and Dissertations

We identified and characterized a novel defect in β-catenin expression in bone marrow derived dendritic cells (BMDC) from NOD mice, a model for human Type I diabetes. This protein is expressed at high levels throughout the lifespan of the mouse and correlates with increased pro-inflammatory cytokine production by the BMDC and IFNγ induction by T cells cocultured with the BMDC. These defects, including a similar pattern of pro-inflammatory cytokine production, are also observed in human monocytederived DC from diabetic patients. After exploring several potential mechanisms involved in the accumulation of β-catenin in NOD BMDC, we found that β-catenin is phosphorylated …

Studies On Tracheorelaxant And Anti-Inflammatory Activities Of Rhizomes Of Polygonatum Verticillatum, Haroon Khan, Muhammad Saeed, Hassan Mehmood, Najeeb-Ur Rehman, Naveed Muhammad, Ikram-Ul Haq, Nadeem Ashraf, Kamal Eldin H El-Tahir, Anwar Gilani

Department of Biological & Biomedical Sciences

Background: The present study describes the tracheorelaxant and anti-inflammatory effects of Polygonatum verticillatum which may support its medicinal use in hyperactive airway complaints and inflammatory disorders.
Methods: The tracheorelaxant activity of crude extract of the rhizomes of P. verticillatum (PR) was assessed in isolated guinea-pig tracheal tissues immersed in tissue organ bath filled with Tyrode's solution and a continuous supply of carbogen gas (95% O2 and 5% CO2). The contractile and relaxant responses of the tissue were measured using isometric transducers coupled with Power-Lab data acquisition system. The anti-inflammatory effect was evaluated in carrageenan-induced rat paw edema model, while the …

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 …

Blood Neutrophil Counts In Hiv-Infected Patients With Pulmonary Tuberculosis: Association With Sputum Mycobacterial Load, Andrew D. Kerkhoff, Robin Y. Wood, David M. Lowe, Monica Vogt, Stephen D. Lawn

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Background

Increasing evidence suggests that neutrophils play a role in the host response toMycobacterium tuberculosis. We determined whether neutrophil counts in peripheral blood are associated with tuberculosis (TB) and with mycobacterial load in sputum in HIV-infected patients.

Methodology/Principal Findings

Adults enrolling in an antiretroviral treatment (ART) clinic in a Cape Town township were screened for TB regardless of symptoms. Paired sputum samples were examined using liquid culture, fluorescence microscopy, and the Xpert MTB/RIF assay. Absolute neutrophil counts (ANC) were measured in blood samples. Of 602 HIV-infected patients screened, 523 produced one or more sputum samples and had complete …

The Proportions Of People Living With Hiv In Low And Middle-Income Countries Who Test Tuberculin Skin Test Positive Using Either A 5 Mm Or A 10 Mm Cut-Off: A Systematic Review, Andrew D. Kerkhoff, Ankur Gupta, Taraz Samandari, Stephen D. Lawn

Microbiology, Immunology, and Tropical Medicine Faculty Publications

No abstract provided.

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 …

Apolipoprotein E Mediates Attachment Of Clinical Hepatitis C Virus To Hepatocytes By Binding To Cell Surface Heparan Sulfate Proteoglycan Receptors, Jieyun Jiang, Xianfang Wu, Hengli Tang, Guangxiang Luo

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Our previous studies demonstrated that the cell culture-grown hepatitis C virus of genotype 2a (HCVcc) uses apolipoprotein E (apoE) to mediate its attachment to the surface of human hepatoma Huh-7.5 cells. ApoE mediates HCV attachment by binding to the cell surface heparan sulfate (HS) which is covalently attached to the core proteins of proteoglycans (HSPGs). In the present study, we further determined the physiological importance of apoE and HSPGs in the HCV attachment using a clinical HCV of genotype 1b (HCV1b) obtained from hepatitis C patients and human embryonic stem cell-differentiated hepatocyte-like cells (DHHs). DHHs were found to resemble primary …

Exosomes Derived From Hiv-1-Infected Cells Contain Trans-Activation Response Element Rna., Aarthi Narayanan, Sergey Iordanskiy, Ravi Das, Rachel Van Duyne, Steven Santos, Elizabeth Jaworski, Irene Guendel, Gavin Sampey, Elizabeth Dalby, Maria Iglesias-Ussel, Anastas Popratiloff, Ramin Hakami, Kylene Kehn-Hall, Mary Young, Caroline Subra, Caroline Gilbert, Charles Bailey, Fabio Romerio, Fatah Kashanchi

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Exosomes are nano-sized vesicles produced by healthy and virus-infected cells. Exosomes derived from infected cells have been shown to contain viral microRNAs (miRNAs). HIV-1 encodes its own miRNAs that regulate viral and host gene expression. The most abundant HIV-1-derived miRNA, first reported by us and later by others using deep sequencing, is the trans-activation response element (TAR) miRNA. In this study, we demonstrate the presence of TAR RNA in exosomes from cell culture supernatants of HIV-1-infected cells and patient sera. TAR miRNA was not in Ago2 complexes outside the exosomes but enclosed within the exosomes. We detected the host miRNA …

Spatially Explicit Modeling Of Schistosomiasis Risk In Eastern China Based On A Synthesis Of Epidemiological, Environmental, And Intermediate Host Genetic Data, Matthias Schrader, Torsten Hauffe, Zhijie Zhang, George M. Davis, Fred Jopp, Justin V. Remais, Thomas Wilke

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Schistosomiasis japonica is a major parasitic disease threatening millions of people in China. Though overall prevalence was greatly reduced during the second half of the past century, continued persistence in some areas and cases of re-emergence in others remain major concerns. As many regions in China are approaching disease elimination, obtaining quantitative data on Schistosoma japonicum parasites is increasingly difficult. This study examines the distribution of schistosomiasis in eastern China, taking advantage of the fact that the single intermediate host serves as a major transmission bottleneck. Epidemiological, population-genetic and high-resolution ecological data are combined to construct a predictive model capable …

Eubacterial Spovg Homologs Constitute A New Family Of Site-Specific Dna-Binding Proteins, Brandon L. Jutras, Alicia M. Chenail, Christi L. Rowland, Dustin Carroll, M Clarke Miller, Tomasz Bykowski, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

A site-specific DNA-binding protein was purified from Borrelia burgdorferi cytoplasmic extracts, and determined to be a member of the highly conserved SpoVG family. This is the first time a function has been attributed to any of these ubiquitous bacterial proteins. Further investigations into SpoVG orthologues indicated that the Staphylococcus aureus protein also binds DNA, but interacts preferentially with a distinct nucleic acid sequence. Site-directed mutagenesis and domain swapping between the S. aureus and B. burgdorferi proteins identified that a 6-residue stretch of the SpoVG α-helix contributes to DNA sequence specificity. Two additional, highly conserved amino acid residues on an adjacent …

Methods For Quantifying T Cell Receptor Binding Affinities And Thermodynamics, Kurt H. Piepenbrink, Brian E. Gloor, Kathryn M. Armstrong, Brian M. Baker

Food for Health: Publications

αβ T cell receptors (TCRs) recognize peptide antigens bound and presented by class I or class II major histocompatibility complex (MHC) proteins. Recognition of a peptide/MHC complex is required for initiation and propagation of a cellular immune response, as well as the development and maintenance of the T cell repertoire. Here we discuss methods to quantify the affinities and thermodynamics of interactions between soluble ectodomains of TCRs and their peptide/MHC ligands, focusing on titration calorimetry, surface plasmon resonance, and fluorescence anisotropy. As TCRs typically bind ligand with weak-to-moderate affinities, we focus the discussion on means to enhance the accuracy and …

Small Molecule Inhibitors Of Hpv16 E6, Chung-Hsiang Yuan

Loma Linda University Electronic Theses, Dissertations & Projects

High-risk human papillomaviruses (HR-HPVs) cause nearly all cases of cervical cancer. HPV 16 E6, one of two viral oncogenes, protects cells from apoptosis by binding to and accelerating the degradation of several apoptotic proteins, including caspase 8 and p53. We proposed that blocking the interactions between HPV E6 and its partners using small molecules had the potential to re-sensitize HPV+ cells to apoptosis. To test this prediction, we screened libraries of small molecules for candidates that could block E6/caspase 8 binding, and identified several candidates from different chemical classes. Testing hits for dose-dependency and specificity in vitro and for toxicity …