Microbiology Commons^™

Neuropathogenic Escherichia Coli K1 Does Not Exhibit Proteolytic Activities To Exert Its Pathogenicity, Junaid Iqbal, Mehak Rajan, Ruqaiyyah Siddiqu, Naveed Ahmed Khan

Department of Biological & Biomedical Sciences

Background: Proteases are well-known virulence factors that promote survival, pathogenesis and immune evasion of many pathogens. Several lines of evidence suggest that the blood-brain barrier permeability is a prerequisite in microbial invasion of the central nervous system. Because proteases are frequently associated with vascular permeability by targeting junctional proteins, here it is hypothesized that neuropathogenic Escherichia coli K1 exhibit proteolytic activities to exert its pathogenicity.
Methods: Zymographic assays were performed using collagen and gelatin as substrates. The lysates of whole E. coli K1 strain E44, or E. coli K-12 strain HB101 were tested for proteolytic activities. The conditioned media were …

Qcm Aptasensor For Rapid And Specific Detection Of Avian Influenza Virus, Luke Brockman

Graduate Theses and Dissertations

There has been a need for rapid detection of avian influenza virus (AIV) H5N1 due to it being a potential pandemic threat. Most of the current methods, including culture isolation and PCR, are very sensitive and specific but require specialized laboratories and trained personnel in order to complete the tests and are time-consuming. The goal of this study was to design a biosensor that would be able to rapidly detect AIV H5N1 using aptamers as biosensing material and a quartz crystal microbalance (QCM) for transducing method. Specific DNA aptamers against AIV H5N1 were immobilized, through biotin and streptavidin conjugation, onto …

Interaction Of Bacillus Anthracis Exosporium Protein Bcla With Complement Factor H And Spore Persistence In The Lung, Sarah A. Jenkins

Dissertations and Theses (Open Access)

Anthrax outbreaks in the United States and Europe and its potential use as a bioweapon have made Bacillus anthracis an interest of study. Anthrax infections are caused by the entry of B. anthracis spores into the host via the respiratory system, the gastrointestinal tract, cuts or wounds in the skin, and injection. Among these four forms, inhalational anthrax has the highest lethality rate and persistence of spores in the lungs of animals following pulmonary exposure has been noted for decades. However, details or mechanisms of spore persistence were not known. In this study, we investigated spore persistence in a mouse …

In Vitro Characterization Of Avian Influenza Virus Isolates With A Truncated Ns1 Gene Segment, Aaron Dick

Honors Scholar Theses

Avian Influenza Virus represents a significant threat to the world poultry population, and is a potential threat to humans due to the possibility of cross-species AIV infection. Our approach is to characterize a number of avian virus populations with respect to their content of biologically active particles that include hemagglutinating particles (HAP), plaque forming particles (PFP), interferon inducing particles (IFP), interferon induction-suppressing particles (ISP), defective-interfering particles (DIP), cell-killing particles (CKP) and non-infectious cell killing particles (niCKP) using unique in vitro assays developed for avian influenza virus in the Marcus-Sekellick Laboratory. Specifically, we will use a strain of Avian influenza virus, …

Malignant Vascular Tumours Associatedwith The Breast: A Study Of 7 Cases, Azizun-Nisa, Zeeshanuddin, Naila Kayani

Department of Pathology and Laboratory Medicine

Angiosarcomas account for less than 0.05% of the malignant neoplasms of the breast. We present here 7 cases of malignant vascular neoplasms of the breast, including 2 cases of postmastectomy Stewart-Treves syndrome. In this case series, most of the patients were young. Tumour was bilateral at presentation in one case. The size of the tumours ranged from 1.6 cm to 11 cm. Although breast angiosarcomas are rare neoplasms, with the increasing use of radiation therapy for breast cancer patients, post-radiation skin lesions should not be ignored.

A Mathematical Model For Antibiotic Resistance In A Hospital Setting With A Varying Population, Edward H. Snyder

Electronic Theses and Dissertations

Antibiotic-resistant bacteria(ARB) is causing increased health risk and cost to society. Mathematical models have been developed to study the transmission of resistant bacteria and the efficacy of preventive measures to slow its spread within a hospital setting. The majority of these models have assumed a constant total hospital population with the admission and discharge rates being equal throughout the duration. But a typical hospital population varies from day to day and season to season. In this thesis, we apply variable admission and discharge daily rates to existing deterministic and stochastic models which examine the transmission of single and dual resistant …

Molecular And Genomic Based Insights Into The Evolution Of Enterococcus Faecium From Commensal To Hospital-Adapted Pathogen, Jessica R. Galloway-Pena

Dissertations and Theses (Open Access)

The basis for the recent transition of Enterococcus faecium from a primarily commensal organism to one of the leading causes of hospital-acquired infections in the United States is not yet understood. To address this, the first part of my project assessed isolates from early outbreaks in the USA and South America using sequence analysis, colony hybridizations, and minimal inhibitory concentrations (MICs) which showed clinical isolates possess virulence and antibiotic resistance determinants that are less abundant or lacking in community isolates. I also revealed that the level of ampicillin resistance increased over time in clinical strains. By sequencing the pbp5 gene, …

Evolution Of Human Immunodeficiency Virus Type 1 Clade C Envelope V1–V5 Region During Disease Progression In Non-Human Primate Model, For Yue Tso

School of Biological Sciences: Dissertations, Theses, and Student Research

Human immunodeficiency virus type 1 (HIV-1) clade C strain is the fastest spreading HIV-1 strain globally, especially in Africa. It has been decades since the acquired immune deficiency syndrome (AIDS) pandemic first started. However, an effective anti-HIV-1 vaccine is not yet available, which is partly due to the highly variable nature of HIV-1 envelope gene and the absence of a suitable animal model. Strengthening of the understanding of envelope evolution during disease progression will contribute significantly towards future anti-HIV-1 treatment and preventions.

Non-human primates have been an essential animal model for many biomedical research areas. Using simian-human immunodeficiency virus (SHIV) …

Development Of A Predictive Modeling System For Validation Of The Cumulative Mirobial Inactivation Of The Salmonellae In Pepperoni Utilizing A Non-Pathogenic Surrogate Microorganism (Enterococcus Faecalis), Scott Donald Stillwell

Graduate Theses and Dissertations

Salmonellosis is the most frequently occurring bacterial foodborne illness in the United States and the human case rate has not improved for the past two decades. The federal agency responsible for oversight of meat and poultry processors has announced the intent to extend existing pathogen reduction performance standards for Salmonella spp. to cover all classes of products including fermented sausages that are currently produced under HACCP plans that are validated for control of Escherichia coli O157:H7. The proposed regulatory modifications will require processors to revalidate HACCP plan controls to achieve either a 6.5 or a 7.0 log10 inactivation of the …

Proteomic Studies Of The Influenza Virus-Human Cell Interactions: The Responses Of Host Cell Protein Expression To Viral Infection And The Novel Host Proteins That Interact With Virus Protein Ns1, Yimeng Wang

Graduate Theses and Dissertations

Influenza A viruses (IAVs) continue to be a threat to human health. Despite extensive studies, the mechanisms underlying the IAVs-host interactions during IAV infection remain elusive. We employed quantitative proteomic methods to systematically explore the host cell protein expression responses to IAV infection and examine the function of a critical IAV protein called NS1 by identifying its host binding partners. Specifically, we used a 2-dimentional gel electrophoresis (2-DE) based proteomic method to screen host proteins whose expression was substantially altered by IAV. One critical protein named IκB kinase-gamma (IKKγ) was found to be significantly down-regulated during IAV infection. Functional studies …

The Presence Of Methicillin Resistant Staphylococcus Aureus (Mrsa) On Environmental Surfaces In Healthcare Facilities Pre- And Post-Cleaning, Aaron Thomas Hunt

UNLV Theses, Dissertations, Professional Papers, and Capstones

The emergence of antibiotic resistant bacteria is a serious public health issue affecting millions of people. Methicillin-resistant Staphylococcus aureus(MRSA) is a leading cause of healthcare acquired infections today. Research has shown that patients infected or colonized with MRSA shed the bacteria into the environment, where the bacteria can survive for long periods of time and become potential sources of infection. Currently, infection prevention efforts focus on active surveillance, hand hygiene, personal protective equipment use and antimicrobial stewardship, with less attention given to environmental cleaning. Nevertheless, environmental cleaning is essential to remove infectious agents from environmental surfaces and prevent transmission. The …

Secretion Of Tcpf By The Vibrio Cholerae Toxin-Coregulated Pilus Biogenesis Apparatus Requires An N-Terminal Determinant, Christina J. Megli, Ronald K. Taylor

Dartmouth Scholarship

Type IV pili are important for microcolony formation, biofilm formation, twitching motility, and attachment. We and others have shown that type IV pili are important for protein secretion across the outer membrane, similar to type II secretion systems. This study explored the relationship between protein secretion and pilus formation in Vibrio cholerae. The toxin-coregulated pilus (TCP), a type IV pilus required for V. cholerae pathogenesis, is necessary for the secretion of the colonization factor TcpF (T. J. Kirn, N. Bose, and R. K. Taylor, Mol. Microbiol. 49:81–92, 2003). This phenomenon is not unique to V. cholerae; secreted …

Novel Neutralizing Antibody Assays For Recombinant Human Hookworm Na-Gst-1 Vaccine, Xi Chen, Brian Keegan, Peter J. Hotez, Jeffrey M. Bethony, Amar R. Jariwala

GW Research Days 2013

BACKGROUND

Necator Americanus, a human hookworm causes approximately 85% of the global hookworm infections. Hookworm ingest hemoglobin containing erythrocytes. Hemoglobin is further digested to Heme and Globin by hookworm's gut enzymes. Iron-containing Heme is a potent enzyme inhibitor and generates toxic reactive oxygen species which is toxic to hookworms. Hookworm's gut enzyme Na-GST-1 (Necator Americanus Glutathione S-Transferase-1) has been hypothesized to detoxify Heme. Na-GST-1 adjuvanted with Alhydrogel® is a new vaccine which is currently under clinical development. Na-GST-1 has two active sites, the ligand binding or Heme detoxification site (H-site) and the catalytic active glutathione binding …

A Review Of G6pd Deficiency In Pakistani Perspective, Bushra Moiz

Department of Pathology and Laboratory Medicine

No abstract provided.

Frequency Of Precancerous Lesions In Endoscopic Gastric Biopsies In Chronic Gastritis, Saroona Haroon, Naveen Faridi, Faisal Rashid Lodhi, Shafaq Mujtaba

Department of Pathology and Laboratory Medicine

Objective:
To determine the frequency of precancerous lesions in endoscopic gastric biopsies of patients with chronic gastritis.STUDY Design: A case series.
Place and duration of study:
Department of Histopathology, Liaquat National Hospital, Karachi, from July 2008 to January 2009.METHODOLOGY: Over 6 months, 375 endoscopic gastric biopsies of patients with age group of 15-65 years having endoscopic chronic gastritis were included. From final biopsy report, basic information like patient demographics and presence of precancerous lesions i.e. activity (chronic active gastritis), atrophy (atrophic gastritis), intestinal metaplasia and dysplasia were recorded on proforma. Results were described as proportions and frequency.
Results:
The frequency …

Cd4 And Cd8 T Cells Directly Recognize Murine Gammaherpesvirus 68-Immortalized Cells And Prevent Tumor Outgrowth, Xiaozhan Liang, Rebecca L. Crepeau, Weijun Zhang, Samuel H. Speck, Edward J. Usherwood

Dartmouth Scholarship

There has been extensive research regarding T cell recognition of Epstein-Barr virus-transformed cells; however, less is known regarding the recognition of B cells immortalized by gamma-2 herpesviruses. Here we show that B cells immortalized by murine gammaherpesvirus 68 (MHV-68, γHV-68) can be controlled by either CD4 or CD8 T cells in vivo. We present evidence for the direct recognition of infected B cells by CD4 and CD8 T cells. These data will help in the development of immunotherapeutic approaches combating gamma-2 herpesvirus-related disease.

Enhanced Phagocytic Activity Of Hiv-Specific Antibodies Correlates With Natural Production Of Immunoglobulins With Skewed Affinity For Fcγr2a And Fcγr2b, Margaret E. Ackerman, Anne-Sophie Dugast, Elizabeth G. Mcandrew, Stephen Tsoukas

Dartmouth Scholarship

While development of an HIV vaccine that can induce neutralizing antibodies remains a priority, decades of research have proven that this is a daunting task. However, accumulating evidence suggests that antibodies with the capacity to harness innate immunity may provide some protection. While significant research has focused on the cytolytic properties of antibodies in acquisition and control, less is known about the role of additional effector functions. In this study, we investigated antibody-dependent phagocytosis of HIV immune complexes, and we observed significant differences in the ability of antibodies from infected subjects to mediate this critical effector function. We observed both …

The Perfect Fit

Colby Magazine

From the classrooms and laboratories of Mayflower Hill, they found their niche in science. Microbiologist Carrie Harwood ’73, transplant surgeon Patrick Wood ’75, and marine biologist Paul Wade ’80 have passion for their professions.

Progress Realized: Trends In Hiv-1 Viral Load And Cd4 Cell Count In A Tertiary-Care Center From 1999 Through 2011, Howard B. Gale, Manuel D. Rodriguez, Heather J. Hoffman, Debra A. Benator, Fred M. Gordin, Ann M. Labriola, Virginia L. Kan

Epidemiology Faculty Publications

Abstract

Accumulating evidence suggests that alterations in immune function may be important in the etiology of papillary thyroid cancer (PTC). To identify genetic markers in immune-related pathways, we evaluated 3,985 tag single nucleotide polymorphisms (SNPs) in 230 candidate gene regions (adhesion-extravasation-migration, arachidonic acid metabolism/eicosanoid signaling, complement and coagulation cascade, cytokine signaling, innate pathogen detection and antimicrobials, leukocyte signaling, TNF/NF-kB pathway or other) in a case-control study of 344 PTC cases and 452 controls. We used logistic regression models to estimate odds ratios (OR) and calculate one degree of freedom P values of linear trend (PSNP-trend) for the association …

Changes In Bacterial Growth Rate Govern Expression Of The Borrelia Burgdorferi Ospc And Erp Infection-Associated Surface Proteins, Brandon L. Jutras, Alicia M. Chenail, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The Lyme disease spirochete controls production of its OspC and Erp outer surface proteins, repressing protein synthesis during colonization of vector ticks but increasing expression when those ticks feed on vertebrate hosts. Early studies found that the synthesis of OspC and Erps can be stimulated in culture by shifting the temperature from 23°C to 34°C, leading to a hypothesis that Borrelia burgdorferi senses environmental temperature to determine its location in the tick-mammal infectious cycle. However, borreliae cultured at 34°C divide several times faster than do those cultured at 23°C. We developed methods that disassociate bacterial growth rate and temperature, allowing …

Control Of Candida Albicans Metabolism And Biofilm Formation By Pseudomonas Aeruginosa Phenazines, Diana K. Morales, Nora Grahl, Chinweike Okegbe, Lars E. P. Dietrich, Nicholas J. Jacobs, Deborah A. Hogan

Dartmouth Scholarship

Candidaalbicanshasdevelopmentalprogramsthatgoverntransitionsbetweenyeastandfilamentousmorphologies and between unattached and biofilm lifestyles. Here, we report that filamentation, intercellular adherence, and biofilm develop- ment were inhibited during interactions between Candida albicans and Pseudomonas aeruginosa through the action of P. aeruginosa-produced phenazines. While phenazines are toxic to C. albicans at millimolar concentrations, we found that lower concentrations of any of three different phenazines (pyocyanin, phenazine methosulfate, and phenazine-1-carboxylate) allowed growth but affected the development of C. albicans wrinkled colony biofilms and inhibited the fungal yeast-to-filament transition. Phenazines impaired C. albicans growth on nonfermentable carbon sources and led to increased production of fer- mentation products (ethanol, glycerol, and …

Phi X 174, David J. Hall

Infectious Pathogens

Phi X 174 database number # 1CD3. Phi X 174 is a virus that infects bacteria and was the first DNA-based genome to be sequenced in 1977. This bacteriophage has a [+] circular single-stranded DNA genome. The assembly of the capsid has been successfully done in vitro and is the focus of many studies on self-assembly, drug delivery and nanotechnology.

Dengue Virus, David J. Hall

Infectious Pathogens

Dengue virus, database # 1THD Dengue fever, is an infectious tropical disease caused by the dengue virus and transmitted by mosquito. Symptoms include fever, headache, muscle and joint pains, and a characteristic skin rash that is similar to measles. In a small proportion of cases the disease develops into the life-threatening dengue hemorrhagic fever. Dengue is a positive strand RNA virus that is part of the flavivirus family. Dengue is an enveloped virus meaning it has a nucleocapsid protecting the RNA and the nucleocapsid is surrounded by lipids (hence the name enveloped).

Human Papilloma Virus 16, David J. Hall

Infectious Pathogens

Human Papilloma virus 16, database# 1DZL Infection by most papillomaviruses is either asymptomatic or causes small benign tumors, known as papillomas or warts (e.g. human papillomavirus HPV6 or HPV11). Papillomas caused by some types, however, such as human papillomaviruses 16 and 18, carry a risk of becoming cancerous. Human papilloma virus is a non-enveloped, double stranded, circular DNA virus.

Hepatitis B, David J. Hall

Infectious Pathogens

Hepatitis B, database # 2g33. Hepatitis B is an infectious inflammatory illness of the liver caused by the hepatitis B virus (HBV). Hepatitis B virus (HBV) is a member of the Hepadnavirus family.The virus particle, (virion) consists of an outer lipid envelope and an icosahedral nucleocapsid core composed of protein. These virions are 42 nM in diameter. The nucleocapsid encloses the viral DNA and a DNA polymerase that has reverse transcriptase activity.

Activation Of Human Herpesvirus Replication By Apoptosis, Alka Prasad, Jil Remick, Steven L. Zeichner

Pediatrics Faculty Publications

A central feature of herpesvirus biology is the ability of herpesviruses to remain latent within host cells. Classically, exposure to inducing agents, like activating cytokines or phorbol esters that stimulate host cell signal transduction events, and epigenetic agents (e.g., butyrate) was thought to end latency. We recently showed that Kaposi's sarcoma-associated herpesvirus (KSHV, or human herpesvirus-8 [HHV-8]) has another, alternative emergency escape replication pathway that is triggered when KSHV's host cell undergoes apoptosis, characterized by the lack of a requirement for the replication and transcription activator (RTA) protein, accelerated late gene kinetics, and production of virus with decreased infectivity. Caspase-3 …

Molecular Architecture Of The Uncleaved Hiv-1 Envelope Glycoprotein Trimer, Youdong Mao, Luis Castillo-Menendez, Liping Wang, Christopher Gu, Alon Herschhorn, Anik Désormeaux, Andrés Finzi, Shi-Hua Xiang, Joseph Sodroski

Nebraska Center for Virology: Faculty Publications

The human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer, a membrane-fusing machine, mediates virus entry into host cells and is the sole virusspecific target for neutralizing antibodies. Binding the receptors, CD4 and CCR5/CXCR4, triggers Env conformational changes from the metastable unliganded state to the fusion-active state. We used cryo-electron microscopy to obtain a 6-Å structure of the membranebound, heavily glycosylated HIV-1 Env trimer in its uncleaved and unliganded state. The spatial organization of secondary structure elements reveals that the unliganded conformations of both gp120 and gp41 subunits differ from those induced by receptor binding. The gp120 trimer association domains, which …

Variations In The Biological Functions Of Hiv-1 Clade C Envelope In A Shiv-Infected Rhesus Macaque During Disease Progression, For Yue Tso, Levon Abrahamyan, Shiu-Lok Hu, Ruth M. Ruprecht, Charles Wood

Nebraska Center for Virology: Faculty Publications

A better understanding of how the biological functions of the HIV-1 envelope (Env) changes during disease progression may aid the design of an efficacious anti-HIV-1 vaccine. Although studies from patient had provided some insights on this issue, the differences in the study cohorts and methodology had make it difficult to reach a consensus of the variations in the HIV-1 Env functions during disease progression. To this end, an animal model that can be infected under controlled environment and reflect the disease course of HIV-1 infection in human will be beneficial. Such an animal model was previously demonstrated by the infection …

Kaposi’S Sarcoma-Associated Herpesvirus Transactivator Rta Induces Cell Cycle Arrest In G0/G1 Phase By Stabilizing And Promoting Nuclear Localization Of P27Kip, Pankaj Kumar, Charles Wood

Nebraska Center for Virology: Faculty Publications

The Kaposi’s sarcoma-associated herpesvirus (KSHV) immediate-early gene, replication, and transcription activator (KRta) is a key viral protein that serves as the master regulator for viral lytic replication. In this study, we investigated the role of K-Rta in cell cycle regulation and found that the expression of K-Rta in doxycycline (Dox)-inducible BJAB cells induced cell cycle arrest in G₀/G₁ phase. Western blot analysis of key cell cycle regulators revealed that K-Rta-mediated cell cycle arrest was associated with a decrease in cyclin A and phosphorylated Rb (pS807/pS811) protein levels, both markers of S phase progression, and an increase in …

Low-Abundance Resistant Mutations In Hiv-1 Subtype C Antiretroviral Therapy-Naïve Individuals As Revealed By Pyrosequencing, Sandra Gonzalez, Damien C. Tully, Clement Gondwe, Charles Wood

Nebraska Center for Virology: Faculty Publications

Given the recent scale-up of antiretroviral therapy (ART) in sub-Saharan Africa, we sought to determine how often and at what levels do drug-resistant mutant variants exist in ART-naïve HIV subtype C infected individuals. Samples from 10 ART-naïve Zambian individuals were subjected to ultra-deep pyrosequencing (UDPS) to characterize the frequency of low-abundance drug resistance mutations in the pol gene. Low-abundance clinically relevant variants were detected for nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs) in eight of the ten subjects. Intermediate to high-level resistance was predicted for the majority of NRTIs. Mutations conferring resistance to …