Microbiology Commons^™

Molecular Epidemiology Of Methicillin-Resistant Staphylococcus Aureus (Mrsa), Ilene Bautista

UNLV Theses, Dissertations, Professional Papers, and Capstones

Staphylococcus aureus is a frequent cause of a myriad of infections in hospitals, healthcare facilities and community settings. It is often related to skin and soft tissue infection, but it can also cause other diseases varying from food poisoning to endocarditis and toxic shock syndrome. According to a study by Kuehnert et al. (2006) there has been a strong association between Staphylococcus aureus (S. aureus) carriage and risk factors for subsequent infections. Subsequent infection from S. aureus , including methicillin-resistant S. aureus (MRSA) infection, can be projected by looking at the presence of S. aureus nasal colonization. The purpose of …

An Evaluation Of Methicillin Resistant Staphylococcus Aureus Survival On Five Environmental Surfaces Under Two Different Humidities, With And Without The Addition Of Bovine Serum Albumin, Courtney Ann Coughenour

UNLV Theses, Dissertations, Professional Papers, and Capstones

The spread of antibiotic resistant bacteria is a major public health concern, as they result in greater healthcare costs and increased morbidity and mortality rates. Methicillin resistant Staphylococcus aureus (MRSA) is one organism of particular concern, with the number of infections increasing in epidemic proportion. Bacterial surface contamination with MRSA is significant, as it may serve as a reservoir for transmission and have negative health implications. The purpose of this study was to evaluate survival of MRSA on five environmental surface materials; glass, wood, vinyl, plastic, and cloth. The effect of relative humidity (RH) and bovine serum albumin (BSA) were …

Morph-Associated Jh Titer Diel Rhythm In Gryllus Firmus: Experimental Verification Of Its Circadian Basis And Cycle Characterization In Artificially Selected Lines Raised In The Field, Anthony J. Zera, Zhangwu Zhao

Anthony Zera Publications

Previous studies demonstrated a high-amplitude, diel cycle for the hemolymph JH titer in the wing-polymorphic cricket, Gryllus firmus. The JH titer rose and fell in the flight-capable morph (long-winged, LW(f)) above and below the relatively temporally invariant JH titer in the flightless (short-winged, SW) morph. The morph-specific JH titer cycle appeared to be primarily driven by a morph-specific diel cycle in the rate of JH biosynthesis. In the present study, cycles of the JH titer and rate of JH biosynthesis in the LW(f) morph persisted in the laboratory under constant darkness with an approximate 24 h periodicity. The JH …

Phenotypic And Genetic Differences In Soil Bacterial Communities Among Successional Stages, Rowena A. G. Hamlet

Theses and Dissertations - UTB/UTPA

The association between soil microbes and plants can influence plant growth and survival as well as alter soil microbial community dynamics. The purpose of this study was to determine how the length of this interaction between plants and bacteria affects the bacterial soil community structure. Soil microbial communities associated with plant communities at different successional stages at the Santa Ana National Wildlife Refuge were investigated. The study sites included three revegetated sites (4 months, 21 months, and 221 months since revegetation) and a control site (native brush, never revegetated). Five soil samples were randomly collected at each site. Soil microbial …

Controlled Assembly Of Rodlike Viruses With Polymers, Tao Li, Laying Wu, Nisaraporn Suthiwangcharoen, Michael A. Bruckman, Dayton Cash, Joan S. Hudson, Soumitra Ghoshroy, Qian Wang

Faculty Publications

A practical method to assemble rodlike tobacco mosaic virus and bacteriophage M13 with polymers was developed, which afforded a 3D core–shell composite with morphological control.

Esat6-Induced Ifngamma And Cxcl9 Can Differentiate Severity Of Tuberculosis., Zahra Hasan, Bushra Jamil, Mussarat Ashraf, Muniba Islam, Muhammad S Yusuf, Javaid A Khan, Rabia Hussain

Department of Pathology and Laboratory Medicine

Background: Protective responses against Mycobacterium tuberculosis are dependent on appropriate T cell and macrophage activation. Mycobacterial antigen six kDa early secreted antigenic target (ESAT6) and culture filtrate protein 10 (CFP10) can detect M. tuberculosis specific IFNgamma responses. However, most studies have been performed in non-endemic regions and to study pulmonary tuberculosis (PTB). We have studied ESAT6 and CFP10 induced cytokine and chemokines responses in PTB and extrapulmonary (EPul) TB.
Methodology: IFNgamma, IL10, CXCL9 and CCL2 responses were determined using an ex vivo whole blood assay system in PTB (n = 30) and EPulTB Patients with limited (LNTB, n = …

Long-Distance Delivery Of Bacterial Virulence Factors By Pseudomonas Aeruginosa Outer Membrane Vesicles, Jennifer M. Bomberger, Daniel P. Maceachran, Bonita A. Coutermarsh, Siying Ye, George A. O'Toole, Bruce A. Stanton, Frederick M. Ausubel

Dartmouth Scholarship

Bacteria use a variety of secreted virulence factors to manipulate host cells, thereby causing significant morbidity and mortality. We report a mechanism for the long-distance delivery of multiple bacterial virulence factors, simultaneously and directly into the host cell cytoplasm, thus obviating the need for direct interaction of the pathogen with the host cell to cause cytotoxicity. We show that outer membrane–derived vesicles (OMV) secreted by the opportunistic human pathogen Pseudomonas aeruginosa deliver multiple virulence factors, including β-lactamase, alkaline phosphatase, hemolytic phospholipase C, and Cif, directly into the host cytoplasm via fusion of OMV with lipid rafts in the host plasma …

Regulation Of The Mazef Toxin-Antitoxin Module In Staphylococcus Aureus And Its Impact On Sigb Expression, Niles P. Donegan, Ambrose L. Cheung

Dartmouth Scholarship

In Staphylococcus aureus, the sigB operon codes for the alternative sigma factor σ^Band its regulators that enable the bacteria to rapidly respond to environmental stresses via redirection of transcriptional priorities. However, a full model of σ^Bregulation in S. aureus has not yet emerged. Earlier data has suggested that mazEF, a toxin-antitoxin (TA) module immediately upstream of the sigB operon, was transcribed with the sigB operon. Here we demonstrate that the promoter P_mazE upstream of mazEF is essential for full σ^B activity and that instead of utilizing autorepression typical of TA systems, sigB …

Altered Regulation Of Aquaporin Gene Expression In Allergen And Il-13-Induced Mouse Models Of Asthma, Carissa M. Krane, Bijia Deng, Venkateshwar Mutyam, Casey A. Mcdonald, Stephen Pazdziorko, Lawrence Mason, Samuel Goldman, Marion Kasaian, Divya Chaudhary, Cara Williams, Melisa W.Y. Ho

Biology Faculty Publications

IL-13 is known to affect many processes that contribute to an asthmatic phenotype, including inflammation, fibrosis, and mucus production. Members of the aquaporin (AQP) family of transmembrane water channels are targets of regulation in models of lung injury and inflammation. Therefore, we examined AQP mRNA and protein expression in allergen and IL-13-induced mouse models of asthma. Lungs from ovalbumin sensitized and ovalbumin challenged (OVA/OVA) and IL-13 treated mice showed airway thickening, increased mucus production, and pulmonary eosinophilia. Pulmonary function tests showed a significant increase in methacholine-induced airway hyperreactivity in OVA/OVA and IL-13-treated mice as compared with controls. Quantitative PCR analysis …

Study Of The Dna Damage Complexes Within The Htlv-1 Tax Oncoprotein Interactome, Sidi Mehdi Belgnaoui

Theses and Dissertations in Biomedical Sciences

Human T-cell leukemia virus type 1 (HTLV-1) is a transforming retrovirus that can give rise to adult T-cell leukemia (ATL) and HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). Tax is a virally encoded oncoprotein that is involved in HTLV-1 mediated cellular transformation. It has been hypothesized that Tax induces genomic instability via repression of the cellular DNA damage repair response. Our laboratory has previously shown that the interaction between Tax and various proteins involved in the DNA-damage response pathway impairs the ability of these proteins to mount an efficient repair response. As part of these observations, we proposed that Tax induces …

Characterization Of Antibiotic Resistance In Vibrio Cholerae Isolated From Ships' Ballast And Other Environmental Sources, Frank Kornegay Thomson Iii

OES Theses and Dissertations

Ships' ballast has been implicated as a vector in the dispersal of invasive species into new environments. Numerous cases have been documented for the introduction of macroorganisms via ballasting operations, but what is less known is the role of ballast water and residuals in the spread of potentially harmful microbes, especially with reference to novel genotypes. Of particular interest are the genes encoding for various forms of antibiotic resistance, many of which are carried on mobile genetic elements. A four-year sampling effort has yielded over 300 putative isolates of Vibrio cholerae from ships' ballast tanks and various environmental sources, of …

Interdependent Regulation Of Cytomegalovirus Proteins In Complex, Lisa L. Bolin

Theses and Dissertations in Biomedical Sciences

Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus that causes significant morbidity and mortality in the immune compromised. Using the mutine cytomegalovirus (MCMV) model, we identified two genes, M140 and M141, which are determinants of macrophage tropism. Monocytes/macrophages are a critical cell type for cytomegalovirus (CMV) pathogenesis as sites of viral latency and by supporting viral replication and disseminating virus throughout the body. We previously found that the localization of the M140/M141 gene products (pM140/pM141) is different when the proteins are co-expressed as compared to their individual expression. When the proteins are individually expressed pM141 localizes diffusely throughout the cytoplasm and, …

Comparison Of Immune Correlates, Age Related Changes And Proteomic Profiling Of Healthy Individuals Receiving Influenza Vaccines, Gaurav Basu

Theses and Dissertations in Biomedical Sciences

The burden of influenza related infections is substantial, both in terms of illness, lives lost and economic impact on society. The degree of impact of influenza related infections is much higher in the elderly population where it is a leading cause of catastrophic disability; greatly affecting the quality of life of elderly persons above 65 years of age. Vaccination is the mainstay for control and prevention of influenza infections. There are two vaccine formulations that are licensed for use at present. The inactivated influenza vaccines (TIIV) which have been used for 60 years in all age groups and the new …

Role Of The Human Cytomegalovirus Ie2 Protein On Transcriptional Regulation Of Viral Promoters, Siabhon Michelle Harris

Theses and Dissertations in Biomedical Sciences

Human cytomegalovirus (HCMV) is a ubiquitous pathogen able to cause severe mortality and morbidity in immuno-compromised individuals. Successful infection by HCMV is dependent on expression of viral genes essential for replication. Immediate early (IE) gene products are the first subset of viral genes to be expressed during infection and function as key transcriptional regulators. IE2 is one the most predominantly expressed IE proteins and is essential for HCMV infection. IE2 transactivates several viral promoters, including those of the essential viral DNA polymerase (UL54) and UL112-113 gene regions. IE2 is also able to autoregulate is own expression and repress expression of …

Comparison Of Replication-Competent, First Generation, And Helper-Dependent Adenoviral Vaccines, Eric A. Weaver, Pramod N. Nehete, Stephanie S. Buchl, Julien S. Senac, Donna Palmer, Philip Ng, K. Jagannadha Sastry, Michael A. Barry

Nebraska Center for Virology: Faculty Publications

All studies using human serotype 5 Adenovirus (Ad) vectors must address two major obstacles: safety and the presence of pre-existing neutralizing antibodies. Helper-Dependent (HD) Ads have been proposed as alternative vectors for gene therapy and vaccine development because they have an improved safety profile. To evaluate the potential of HD-Ad vaccines, we compared replication-competent (RC), first-generation (FG) and HD vectors for their ability to induce immune responses in mice. We show that RC-Ad5 and HD-Ad5 vectors generate stronger immune responses than FG-Ad5 vectors. HD-Ad5 vectors gave lower side effects than RC or FG-Ad, producing lower levels of tissue damage and …

Biomarkers Of Hiv-1 Associated Dementia: Proteomic Investigation Of Sera, Jayme Wiederin, Wojciech Rozek, Fenghai Duan, Pawel Ciborowski

Nebraska Center for Virology: Faculty Publications

Background: New, more sensitive and specific biomarkers are needed to support other means of clinical diagnosis of neurodegenerative disorders. Proteomics technology is widely used in discovering new biomarkers. There are several difficulties with in-depth analysis of human plasma/ serum, including that there is no one proteomic platform that can offer complete identification of differences in proteomic profiles. Another set of problems is associated with heterogeneity of human samples in addition intrinsic variability associated with every step of proteomic investigation. Validation is the very last step of proteomic investigation and it is very often difficult to validate potential biomarker with desired …

Pathogenic Adaptation Of Intracellular Bacteria By Rewiring A Cis-Regulatory Input Function, Suzanne E. Osborne, Don Walthers, Ana M. Tomljenovic, David T. Mulder, Uma Silphaduang, Nancy Duong, Michael J. Lowden

Dartmouth Scholarship

The acquisition of DNA by horizontal gene transfer enables bacteria to adapt to previously unexploited ecological niches. Although horizontal gene transfer and mutation of protein-coding sequences are well-recognized forms of pathogen evolution, the evolutionary significance of cis-regulatory mutations in creating phenotypic diversity through altered transcriptional outputs is not known. We show the significance of regulatory mutation for pathogen evolution by mapping and then rewiring a cis-regulatory module controlling a gene required for murine typhoid. Acquisition of a binding site for the Salmonella pathogenicity island-2 regulator, SsrB, enabled the srfN gene, ancestral to the Salmonella genus, to play a …

Cytokine Gene Polymorphisms Across Tuberculosis Clinical Spectrum In Pakistani Patients., Ambreen Ansari, Najeeha Talat, Bushra Jamil, Zahra Hasan, Tashmeem Razzaki, Ghaffar Dawood, Rabia Hussain

Department of Pathology and Laboratory Medicine

Background:Pakistan ranks 7(th) globally in terms of tuberculosis (TB) disease burden (incidence 181/100000 pop./yr, prevalence of 329/pop./yr). Reports from different populations show variable associations of TB susceptibility and severity with cytokine gene polymorphisms. Tuberculosis clinical severity is multi-factorial and cytokines play a pivotal role in the modulation of disease severity. We have recently reported that the ratio of two key cytokines (IFNgamma and IL10) show significant correlation with the severity spectrum of tuberculosis. The objective of the current study was to analyze the frequency of cytokine gene polymorphisms linked to high and low responder phenotypes (IFNgamma +874 T(hi)-->A(lo) …

The Use Of Spider Webs As Passive Bioaerosol Collectors, Daniel I. Mattei

Theses and Dissertations

In this experiment, spider webs demonstrated their suitability as passive bioaerosol collectors. For spider webs to be considered suitable passive collectors webs had to satisfy three basic conditions; (1) collection of microorganisms without discrimination based on species or size, (2) collection under variable environmental conditions, and (3) saturation avoidance in the presence of strong microbial launching sources. Four field sampling locations were used, a waste water treatment facility, a commercial garden center, a secluded state park area, and a parking garage. Microscopy cover glass slides were used as the collection instrument. The methodology assured sterility during collection and promoted in …

Lapd Is A Bis-(3′,5′)-Cyclic Dimeric Gmp-Binding Protein That Regulates Surface Attachment By Pseudomonas Fluorescens Pf0–1, Peter D. Newell, Russell D. Monds, George A. O'Toole

Dartmouth Scholarship

The second messenger cyclic dimeric GMP (c-di-GMP) regulates surface attachment and biofilm formation by many bacteria. For Pseudomonas fluorescens Pf0-1, c-di-GMP impacts the secretion and localization of the adhesin LapA, which is absolutely required for stable surface attachment and biofilm formation by this bacterium. In this study we characterize LapD, a unique c-di-GMP effector protein that controls biofilm formation by communicating intracellular c-di-GMP levels to the membrane-localized attachment machinery via its periplasmic domain. LapD contains degenerate and enzymatically inactive diguanylate cyclase and c-di-GMP phosphodiesterase (EAL) domains and binds to c-di-GMP through a degenerate EAL domain. We present evidence that LapD …

Salt-Induced And Salt-Suppressed Proteins In Tomato Leaves, Suping Zhou, Roger Sauve, Tara Fish, Theodore W. Thannhauser

Agricultural and Environmental Sciences Faculty Research

Tomato (Solanum lycopersicum cv. Money Maker) seedlings at the two-leaf stage were grown in one-half strength Hoagland solution supplemented with 50 mm NaCl for 4 days, with 100 mm NaCl for 4 days, with 150 mm NaCl for 4 days, and with a final concentration 200 mm NaCl for 2 days. Solutions were refreshed every 2 days for treated and untreated seedlings. Non-treated plants were grown in nonamended one-half strength Hoagland solution. Three biological replicates (BR) were included for treated and control experiments. At the end of treatments, the uppermost three newly expanded leaves from all 12 plants in each …

Multimeric Hemicellulases Facilitate Biomass Conversion, Zhanmin Fan, Kurt Wagschal, Wei Chen, Michael D. Montross, Charles C. Lee, Ling Yuan

Plant and Soil Sciences Faculty Publications

Two highly active trifunctional hemicellulases were constructed by linking the catalytic portion of a xylanase with an arabinofuranosidase and a xylosidase, using either flexible peptide linkers or linkers containing a cellulose-binding domain. The multifunctional enzymes retain the parental enzyme properties and exhibit synergistic effects in hydrolysis of natural xylans and corn stover.

From Genome-Based In Silico Predictions To Ex Vivo Verification Of Leprosy Diagnosis, Annemieke Geluk, John S. Spencer, Kidist Bobosha, Maria C. V. Pessolani, Geraldo M. B. Pereira, Sayera Banu, Nadine Honore, Stephen T. Reece, Murdo Macdonald, Bishwa Raj Sapkota, Chaman Ranjit, Kees L. M. C. Franken, Martha Zewdie, Abraham Aseffa, Rabia Hussain, Mariane M. Stefani, Sang-Nae Cho, Linda Oskam, Patrick J. Brennan, Hazel M. Dockrell

Department of Pathology and Laboratory Medicine

The detection of hundreds of thousands of new cases of leprosy every year suggests that transmission of Mycobacterium leprae infection still continues. Unfortunately, tools for identification of asymptomatic disease and/or early-stage M. leprae infection (likely sources of transmission) are lacking. The recent identification of M. leprae-unique genes has allowed the analysis of human T-cell responses to novel M. leprae antigens. Antigens with the most-promising diagnostic potential were tested for their ability to induce cytokine secretion by using peripheral blood mononuclear cells from leprosy Patients and controls in five different areas where leprosy is endemic, 246 individuals from Brazil, Nepal, Bangladesh, …

Effects Of The Pathogenic Water Mold Saprolegnia Ferax On Survival Of Amphibian Larvae, John M. Romansic, Kristin A. Diez, Elise M. Higashi, James E. Johnson, Andrew R. Blaustein

All Faculty Scholarship for the College of the Sciences

Infectious diseases are a significant threat to worldwide biodiversity. Amphibian declines, a significant part of current biodiversity losses, are in many cases associated with infectious disease. Water molds are one group of pathogens affecting amphibians on a worldwide basis. Although water molds have been studied extensively for their effects on host embryos, little information is available about how they affect post-embryonic amphibians. We tested the effects of one species of water mold, Saprolegnia ferax, in a comparative study of larvae of 4 amphibian species: Pseudacris regilla (Pacific treefrog), Rana cascadae (Cascades frog), Ambystoma macrodactylum (long-toed salamander), and R. aurora (red-legged …

An Essay On Evolution: Evolution And The Origin Of Life Are Separate And Distinct Concepts, Kenneth Nickerson

Kenneth Nickerson Papers

Two years ago on a Saturday morning, I was asked quite pointedly by two friends how I could be both spiritual and a scientist. My questioning friends felt that these qualities were incompatible. It turned out their church taught that scientists were ‘the enemy’ because scientists believe in evolution. Since that time, Letters to the Editor regarding evolution have attracted my attention. Many of the published letters stated that the author did not believe in evolution, and argued in support of his/her position that God had created life. The authors thoroughly confuse two concepts which are separate and distinct: Evolution …

Molecular Coevolution Of Pacific Northwest Hantaviruses And Their Host, The Deer Mouse, Peromyscus Maniculatus, Philip Darren Jones

Dissertations and Theses

Sin Nombre virus (SNV, family Bunyaviridae, genus Hantavirus), hosted by the deer mouse, Peromyscus maniculatus (family Cricetidae, Subfamily Neotominae), is the primary etiological agent of Hantavirus pulmonary syndrome (HPS) in the western United States. HPS, with known pathogenicity only to humans and for which there is no cure or prophylaxis, affects the epithelium of the lungs by making the capillaries leaky, thereby resulting in bilateral infiltrates, and eventually leading to respiratory failure and death by drowning in approximately 38% of hospitalized patients.

In the Americas, Peromyscus has been co-evolving with hantaviruses for approximately 12–20 million years, since the first …

Temperature Influence And Heat Management Requirements Of Microalgae Cultivation In Photobioreactors, Thomas Hagen Mehlitz

Master's Theses

Microalgae are considered one of the most promising feedstocks for biofuel production for the future. The most efficient way to produce vast amounts of algal biomass is the use of closed tubular photobioreactors (PBR). The heat requirement for a given system is a major concern since the best algae growth rates are obtained between 25-30 °C, depending on the specific strain. A procedure to determine temperature influence on algal growth rates was developed for a lab-scale PBR system using the species Chlorella. A maximum growth rate of 1.44 doublings per day at 29 °C (optimal temperature) was determined. In addition, …

Diversity Of Estrogen Degrading Microorganisms In Las Vegas Wash And Lake Mead, Nevada, Usa, Susanna Blunt, Jim Bruckner, Jenny C. Fisher, Duane P. Moser

Lake Mead Science Symposium

Endocrine disrupting chemicals (EDCs) are a subject of intense research as more studies reveal their persistence in the environment and detrimental effects on wildlife. Steroid hormones, including the natural and synthetic estrogens estrone (E1), 17-beta-estradiol (E2) and 17- alpha-ethinyl estradiol (EE2), are among the most bioactive and have been detected at low concentrations in waterways downstream from wastewater treatment plants. Las Vegas Wash, a stream flowing into Lake Mead and fed primarily by treated wastewater, provides a unique experimental system in which to study the role microorganisms play in the fate and dispersal of these compounds in surface waters.

Overexpression Of Mazfsa In Staphylococcus Aureus Induces Bacteriostasis By Selectively Targeting Mrnas For Cleavage, Zhibiao Fu, Sandeep Tamber, Guido Memmi, Niles P. Donegan, Ambrose L. Cheung

Dartmouth Scholarship

The role of chromosomally encoded toxin-antitoxin (TA) loci in bacterial physiology has been under debate, with the toxin proposed as either an inducer of bacteriostasis or a mediator of programmed cell death (PCD). We report here that ectopic expression of MazFSa, a toxin of the TA module from Staphylococcus aureus, led to a rapid decrease in CFU counts but most cells remained viable as determined by differential Syto 9 and propidium iodide staining after MazFSa induction. This finding suggested that the toxin MazFSa induced cell stasis rather than cell death. We also showed that MazFSa selectively cleaves cellular mRNAs in …

Severity Of Root Rot In Mature Subterranean Clover And Associated Fungal Pathogens In The Wheatbelt Of Western Australia, Tim Scanlon, Tiernan A. O’Rourke, Martin J. Barbetti, Megan H. Ryan, Len J. Wade, Alan C. Mckay, Ian T. Riley, Hua Li, Krishnapillai Sivasithamparam

Journal articles

Pasture decline is considered to be a serious challenge to agricultural productivity of subterranean clover across southern Australia. Root disease is a significant contributing factor to pasture decline. However, root disease assessments are generally carried out in the early part of the growing season and in areas predominantly sown to permanent pastures. For this reason, in spring 2004, a survey was undertaken to determine the severity of root disease in mature subterranean clover plants in pastures located in the wheatbelt of Western Australia. DNA-based soil assays were used to estimate population density in the soil of a variety of soil-borne …