Microbiology Commons^™

Characterizing The Roles Of Staphylococcus Aureus Secreted Factors In Virulence And Modulation Of Innate Immune Cell Activity, Cameron Harvey

Master's Theses

Staphylococcus aureus is a prominent human pathogen that is responsible for a massive burden on healthcare. This thesis takes two approaches to characterize how S. aureus secreted factors subvert the innate immune response. First, characterization of the integral membrane protease 1984 showed that it regulates secretion of a putative lytic transglycosylase, IsaA, which is implicated in virulence. My results suggest IsaA and 1984 are capable of modulating immune responses that result in enhanced heart colonization in vivo. In addition, recent studies have uncovered TLR-independent pathways that induce inflammatory responses after S. aureus insult. Therefore, I hypothesized the bacterium secretes factors …

Exploring The Short-Term Effects Of Probiotic And Prebiotic Supplementation On The Microbiota And Physiology Of Male C57bl/6 Mice, Miguel Angel Rivas

Wayne State University Theses

The gut microbiome may play a role in the development of chronic diseases like obesity, diabetes, and heart disease. Diets including prebiotics or probiotics can alter the abundance of gut bacterial groups and have subsequent health effects. In this study we wanted to establish a method for comparing the benefits of commercial supplements that alter the microbiota by monitoring fecal microbial profiles in male C57BL/6 mice (n = 24) exposed to 15 days of dietary supplementation. A probiotic diet (VSL#3) and a prebiotic diet (potato starch) were compared to a standard diet (n = 8 for each group). Microbial profiles …

Coordination Of Different Ligands To Copper(Ii) And Cobalt(Iii) Metal Centers Enhances Zika Virus And Dengue Virus Loads In Both Arthropod Cells And Human Keratinocytes, Shovan Dutta, Michael J. Celestine, Supreet Khanal, Alexis Huddleston, Colin Simms, Jessa Faye Arca, Amlam Mitra, Loree Heller, Piotr Kraj, Michael Ledizet, John F. Anderson, Girish Neelakanta, Alvin A. Holder, Hameeda Sultana

Biological Sciences Faculty Publications

Trace elements such as copper and cobalt have been associated with virus-host interactions. However, studies to show the effect of conjugation of copper(II) or cobalt(III) metal centers to thiosemicarbazone ligand(s) derived from either food additives or mosquito repellent such as 2-acetylethiazole or citral, respectively, on Zika virus (ZIKV) or dengue virus (serotype 2; DENV2) infections have not been explored. In this study, we show that four compounds comprising of thiosemicarbazone ligand derived from 2-acetylethiazole viz., (E)-N-ethyl-2-[1-(thiazol-2-yl)ethylidene]hydrazinecarbothioamide (acetylethTSC) (compound 1), a copper(II) complex with acetylethTSC as a ligand (compound 2), a thiosemicarbazone ligand-derived from citral (compound 3) and a cobalt(III) complex …

Cyclic Adenosine Monophosphate Signaling In Mycobacterium Tuberculosis : New Insights Into A Universal Second Messenger, Richard Mcpherson Johnson

Legacy Theses & Dissertations (2009 - 2024)

Despite being the focus of intense research for many years Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), remains the deadliest bacterial pathogen plaguing mankind today. Humans are the sole host and reservoir for Mtb, and Mtb has coevolved closely with its human host for thousands of years. Mtb currently infects over two billion people worldwide and over 1.5 million people die from TB each year, arguably making Mtb the most successful bacterial pathogen on the planet.

Investigation Of The Ms2 Bacteriophage Capsid As An Mri-Capable, Brain-Targeted Nanoparticle Platform, Stephanie M. Curley

Legacy Theses & Dissertations (2009 - 2024)

Novel methods are needed to traverse the blood-brain barrier (BBB) and deliver drugs to specific targets in the brain. To this end, MS2 bacteriophage was explored as a multifunctional transport and targeting vector. The MS2 capsid exterior was modified with two different targeting moieties for delivery across the BBB and targeting specific regions of interest in the brain. Successful modification of MS2 capsids with a brain targeting peptide and NMDAR2D-targeting antibody was confirmed by immunoblotting and fluorescence detection. To measure transport efficiency of MS2 particles across an in vitro BBB model, a highly sensitive RT-qPCR protocol was developed and implemented. …

Non-Naturally Occurring Porcine Reproductive And Respiratory Syndrome Virus (Prrsv) And Methods Of Using, Hiep Lai Xuan Vu, Fernando Osorio, William W. Laegreid, Asit K. Pattnaik, Fangrui Ma

Nebraska Center for Virology: Faculty Publications

A non-naturally occurring porcine reproductive and respiratory syndrome virus (PRRSV) is provided herein, and methods of making and using the non-naturally occurring PRRSV also are provided.

Universal Swine Influenza Antigen And Vaccine, Zhao Wang

Electronic Theses and Dissertations

Swine influenza A viruses pose a serious concern for global health and worldwide swine industry considering their evasion from vaccine-induced immune responses. Formulation of effective influenza vaccines can be complicated by both antigenic shift to a different subtype of hemagglutinin (HAs) and antigenic drift within a particular HA subtype. To address these concerns, we employed a systematic approach to determine the antigenic determinants of swine influenza A viruses by focusing on H1 and H3 subtypes. In parallel, we used a cross-disciplinary approach including structural biology and modeling, virology, and immunology to identify swine influenza A virus-derived HA fusion intermediates broadly …

Surveillance Of South Dakota Mosquito Abundance, Infection Rate, And Insecticide Susceptibility, Geoffrey P. Vincent

Electronic Theses and Dissertations

The aim of this dissertation was to survey and evaluate the abundance, infection rate, and insecticide susceptibility of mosquito fauna present in South Dakota. Mosquito surveillance has been conducted across South Dakota to record and track potential West Nile virus (WNV) vectors from 2004 to 2017. The nuisance mosquito Aedes vexans was found to be the most abundant species overall in the state and most abundant in many of the regions. The WNV vector, Culex tarsalis, was found to be the second most abundant mosquito and the most abundant vector mosquito across the state. However, geospatial variation did exist between …

Serological Evidence For The Co-Circulation Of Two Lineages Of Influenza D Virus In Equine Populations Of The Midwest United States, Hunter Theodore Nedland

Electronic Theses and Dissertations

Influenza D virus (IDV) is a newly described lineage of the Orthomyxoviridae virus family that was first isolated from diseased swine in 2011 and has subsequently been detected in cattle around the world in 2014. In addition, serological evidence for IDV infection in humans has been recently established. Despite all the progress, the full range of susceptible hosts for this novel virus has yet to be determined, but includes swine, bovine, small ruminants and human. This study was designed to determine if equine is a possible host to this newly emerging influenza virus. 364 equine serum samples were collected in …

Improving The Nutritional Characteristics Of Plant Feedstuff By-Products Using Fungal Metabolism, Jacob Zahler

Electronic Theses and Dissertations

Plant feedstuff by-products such as soy processing wastewater, guar korma meal, and sorghum hominy are very different, however, all possess a rich nutrient profile. Lessening their value is the presence of lignocellulose, plant anti-nutritional factors, and unfavorable protein profiles. Fungal conversion processes are an attractive approach to improving the value of these by-products by degrading detrimental fractions of each while simultaneously creating nutrient-rich cell mass. The aim of this research was to improve the value of each by-product for potential application in monogastric diets such as fish. Fungal organisms, both yeast and filamentous fungi, were examined for their ability to …

Dissecting Rna Silencing Pathways In Sclerotinia Sclerotiorum, Pauline Mochama

Electronic Theses and Dissertations

RNA silencing, also known as RNA interference, is an essential mechanism in plants, animals and fungi that functions in gene regulation and defense against foreign nucleic acids. In fungi, RNA silencing has been shown to function primarily in defense against invasive nucleic acids. RNA-silencing- deficient fungi show increased susceptibility to virus infection. Plant pathogenic fungi also utilize RNA silencing to silence plant host immunity genes through the delivery of fungal small RNAs into plants. This cross-kingdom RNA silencing facilitates fungal infection of plants. Overall, these findings demonstrate the significant contributions of fungal RNA silencing pathways to fungal virulence and viral …

Replication, Virulence, And Pathogenesis Of Influenza Viruses, Chithra Chembil Sreenivasan

Electronic Theses and Dissertations

Influenza D virus (IDV) is a novel influenza virus that infects cattle and swine, with cattle as its primary host species. The goal of our first study was to investigate the replication and transmission of bovine IDV in guinea pigs. Following direct intranasal inoculation of animals, the virus was detected in nasal washes of infected animals during the first 7 days post-infection. High viral titers were obtained from nasal turbinates and lung tissues of directly inoculated animals. Further, bovine IDV was able to transmit from the infected guinea pigs to sentinel animals by means of contact and not by aerosol …

Microbiology: A Laboratory Experience, Holly Ahern

Milne Open Textbooks

As a group of organisms that are too small to see and best known for being agents of disease and death, microbes are not always appreciated for the numerous supportive and positive contributions they make to the living world. Designed to support a course in microbiology, Microbiology: A Laboratory Experience permits a glimpse into both the good and the bad in the microscopic world. The laboratory experiences are designed to engage and support student interest in microbiology as a topic, field of study, and career.

This text provides a series of laboratory exercises compatible with a one-semester undergraduate microbiology or …

Immunization By Radiotherapy: Enhancing An Immune-Mediated Abscopal Effect, Amy Steffen

Biology and Microbiology Graduate Students Plan B Research Projects

Radiotherapy aims to destroy tumors by inducing DNA damage in their cells at the local irradiation site. Its immune-mediated systemic effects, called abscopal effect, has shown to enhance anti-tumor immunity when combined with immune therapies and thus, have gained attention by researchers and clinicians to investigate. Below is a summary of the fundamentals of cancer and the immune system’s response to it, as well as the changes in the phenotype and microenvironment of tumor cells after exposure to radiation. Impacts of the abscopal effect and the induction of effective antitumor immunity with various immune therapy strategies will be outlined. The …

Increasing The Clinical Efficacy Of Radiotherapeutics For Solid Tumors By Inhibition Of Hypoxia Inducible Factor-1a, Austin Levi Walz

Biology and Microbiology Graduate Students Plan B Research Projects

Radiotherapy is commonly used in a variety of tumor types and is effective in control of long term progression and may be curative under certain circumstances. Radiotherapeutics have been shown to be the single most effective therapeutic for cancer and only account for 5% of the total cost. However, treatment of cells with radiation causes the tumor microenvironment to undergo changes and leads to cycles of hypoxia inside the tumor which allows for the cell to undergo angiogenesis, metastasize and may lead to repopulation of the tumor. Current systemic chemotherapeutics typically have an additive toxicity due to the unintended targeting …

A Review Of Multiple Sclerosis Treatments: Interferon Beta, Glatiramer Acetate, Fingolimod, And Natalizumab, Ryan Golden

Biology and Microbiology Graduate Students Plan B Research Projects

Multiple Sclerosis (MS) is an autoimmune disease in which the body’s own immune system works to demyelinate the myelin sheaths in the central nervous system. The beginning of the review will concentrate on the history of MS while also describing how MS, the disease, differs from that of normal immune responses. The review then shifts to the four different stages of MS and how to differentiate between the stages, since the treatment options are often dependent on the stage of MS that the patient is in. The main focus of this review is to take an in depth look on …

A Biological Review Of Mental Illness: An Overview Of Genetics And Pathophysiology Of Schizophrenia, Major Depression, And Addiction, Christopher R. Angerhofer

Biology and Microbiology Graduate Students Plan B Research Projects

Novel approaches in understanding mental illness present solutions to current issues in treatment and diagnosis. With advancements in genetics and neurology, the etiology and pathophysiology of mental illness is slowly unwrapping. In discovering biomarkers for depression, addiction, and schizophrenia, the precision for preventing, diagnosing, and treating these disorders increases. The aim of this paper is to review current research for addiction, major depression, and schizophrenia in genetics and physiology, while also clarifying the need for reclassifying mental illness as diseases with a pathophysiological basis, not syndromal, idiopathic disorders. Mental illness is dynamic in that it encompasses both environmental and biological …

Mild Traumatic Brain Injuries And Cte: A Review Highlighting The Connection Between The Two, Leandre Kennedy

Biology and Microbiology Graduate Students Plan B Research Projects

Chronic Traumatic Encephalopathy (CTE) is a traumatic brain injury based disease that is garnering a lot of attention in the United States. The purpose of this paper is to conduct an extensive review of the information available about the condition. Recently there has been a limited amount of published information and treatment opportunities are rare since the only way of diagnosing has come post mortem. Various literary reviews and experiments were analyzed for appropriate information regarding CTE’s pathology and treatments and only peer reviewed published works were allowed in this paper. This resulted in promising information about the disease and …

The Response Of Unpolarized Macrophages (Raw 264.7)/Keratinocytes (Pam-212) Monolayer And Co-Culture System To Herpes Simplex Virus Type 1 (Hsv-1) Replication During The Infection., Fahad Mohammed Alradi

Browse all Theses and Dissertations

Keratinocytes and neurons cells are the main target for Herpes Simplex Virus Type 1 (HSV-1) invasion. Moreover, keratinocytes are the most abundant cell types in the epidermis layer in the skin. Therefore, they are the first cells to encounter HSV-1 in the primary infection. Next, the virus reaches the nerve endings and is transferred to neuronal cells as a result from the primary infection. In between these two events, innate immune cells including monocytes and macrophages response is activated and recruited to the infection site. In this study, keratinocytes (PAM-212) and murine macrophage (RAW 264.7) cell lines were utilized to …

Virus Production And Cell Viability Of Hsv-1-Infected Murine Keratinocytes (Hel-30) Co-Cultured With Murine Macrophages (Raw 264.7), Barry Graffagna

Browse all Theses and Dissertations

Keratinocytes are the most abundant type of cell in the outer layer of skin, the epidermis, and provide barrier against pathogens from invading. However, Herpes Simplex Virus Type 1 (HSV-1) targets these keratinocytes for infection, and later infects neurons to establish lifelong latency. The keratinocytes stimulate the innate immune system to engage and to destroy the virus. Among the cells of the innate immune system to respond to the viral invasion is the macrophage. In this study, RAW 264.7 macrophage and HEL-30 keratinocyte monolayers were challenged in vitro with HSV-1 at a multiplicity of infection (MOI) of 0.1 to investigate …

Marine Bioactives From Saccharina Latissima, Orlaith O'Connell

Masters

Due to rapid global urbanization and therefore increased adoption of a 'Westernized' lifestyle, including decreased physical activity and increased consumption of highly processed and refined foods with a high sugar, fat and salt content, prevalence of gastrointestinal disorders are on the rise. Inflammatory bowel disease (IBD) in particular is closely associated with this type of lifestyle. IBD is a term used to describe chronic inflammatory conditions which affects all or parts of the gastrointestinal tract. It includes conditions such as Crohn's Disease, which affects all the gastrointestinal tract and Ulcerative Colitis which mainly affects the colan. Due to the role …

การเตรียมฟิล์มวัสดุเชิงประกอบทางชีวภาพระหว่างพอลิไฮดรอกซีบิวทิเรตจาก Cupriavidus Necator สายพันธุ์ A-04 และไมโครคริสตัลลีนเซลลูโลสจากใบสับปะรด, พิชญ์นันท์ สินสุขอุดมชัย

Chulalongkorn University Theses and Dissertations (Chula ETD)

พอลิไฮดรอกซีบิวทิเรต (polyhydroxybutyrate, PHB) เป็นพอลิเอสเทอร์ชีวภาพในกลุ่มของพอลิไฮดรอกซีแอลคาโนเอต (polyhydroxyalkanoate, PHAs) ที่ได้รับความสนใจในการศึกษาเพื่อนำมาใช้เป็นวัสดุชีวภาพทางเลือกเพื่อแก้ไขปัญหาสิ่งแวดล้อมจากพลาสติกจากอุตสาหกรรมปิโตรเคมี แม้ว่าจะมีข้อดีที่มากมายแต่ยังมีอุปสรรคในการผลิต PHB ในระดับอุตสาหกรรม เนื่องจากต้นทุนการผลิตที่มีราคาสูง ในงานวิจัยนี้จึงมีจุดประสงค์เพื่อศึกษาการเตรียมฟิล์มวัสดุเชิงประกอบชีวภาพเพื่อลดต้นทุนการผลิต โดยเริ่มจากการผลิต PHB โดย Cupriavidus necator สายพันธุ์ A-04 ในระดับถังหมัก อัตราส่วนระหว่างคาร์บอนและไนโตรเจนเท่ากับ 200 โดยใช้น้ำตาลฟรักโทสเป็นแหล่งคาร์บอน และใช้แอมโมเนียมซัลเฟตเป็นแหล่งไนโตรเจน ได้ปริมาณ PHB สูงสุด 60.54±5.74 เปอร์เซ็นต์ที่ชั่วโมงที่ 60 จากนั้นนำสกัดเซลล์แห้งและทำบริสุทธิ์จะได้เป็นผง PHB บริสุทธิ์ จากนั้นเตรียมไมโครคริสตัลลีนเซลลูโลสจากใบสับปะรดซึ่งเป็นวัสดุเหลือทิ้งทางการเกษตร แต่ไมโครคริสตัลลีนเซลลูโลสละลายได้ในคลอโรฟอร์มใช้เป็นตัวทำละลายในการเตรียมฟิล์มวัสดุเชิงประกอบชีวภาพร่วมกับ PHB จึงต้องดัดแปรโครงสร้างของไมโครคริสตัลลีนเซลลูโลสด้วยปฏิกิริยาเอสเทอริฟิเคชันโดยใช้ลอโรอิลคลอไรด์เป็นสารดัดแปร พบว่าเซลลูโลสลอเรตสามารถละลายได้ในคลอโรฟอร์มและมีการเปลี่ยนแปลงของหมู่ฟังก์ชันเมื่อวิเคราะห์โครงสร้างด้วยเครื่อง FTIR จากนั้นนำผง PHB และเซลลูโลสลอเรตมาขึ้นรูปเป็นแผ่นฟิล์มด้วยวิธีการหล่อขึ้นรูปโดยใช้สารละลายคลอโรฟอร์มที่อัตราส่วนต่างๆ ได้แก่ 100:0, 95:5, 90:10, 85:15, 80:20 และ 0:100 พบว่าแผ่นฟิล์มวัสดุเชิงประกบอชีวภาพที่อัตราส่วนต่างๆ ไม่มีการเปลี่ยนแปลงสมบัติทางความร้อน ในขณะที่ค่ามอดุลัสของยังมีแนวโน้มลดลงอย่างมีนัยสำคัญเมื่อปริมาณของเซลลูโลสลอเรตเพิ่มขึ้น และเมื่อนำไปศึกษาควาสามารถในการย่อยสลายทางชีวภาพพบว่าอัตราส่วน 95:5 ย่อยสลายได้สูงที่สุดเท่ากับ 23.49 เปอร์เซ็นต์ ในวันที่ 35

ผลของเซลลูโลสดัดแปรต่อสมบัติทางกายภาพและความสามารถในการย่อยสลายทางชีวภาพของฟิล์มวัสดุเชิงประกอบชีวภาพที่เตรียมจากพอลิไฮดรอกซีบิวทิเรตผลิตโดย Cupriavidus Necator สายพันธุ์ A-04 และไมโครคริสตัลลีนเซลลูโลสจากกากมันสำปะหลัง, ภัสราภรณ์ ธีระสีมาธรรม

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์ในการเตรียมแผ่นฟิล์มวัสดุเชิงประกอบชีวภาพระหว่าง PHB ซึ่งผลิตโดย Cupriavidus necator สายพันธุ์ A-04 และไมโครคริสตัลลีนเซลลูโลสที่เตรียมจากกากมันสำปะหลังเพื่อปรับปรุงเสถียรภาพทางความร้อนและสมบัติเชิงกลของ PHB เริ่มจากการเพาะเลี้ยง C. necator สายพันธุ์ A-04 ในระดับถังหมัก ได้ปริมาณ PHB เท่ากับ 59.66 ± 5.92 เปอร์เซ็นต์ต่อน้ำหนักเซลล์แห้ง จากนั้นสกัดและทำบริสุทธิ์ PHB จากเซลล์แห้ง แล้วนำไปวิเคราะห์หมู่ฟังก์ชันในโครงสร้างและสมบัติทางความร้อนของ PHB ที่สกัดได้พบว่า PHB มีหมู่ฟังก์ชันและสมบัติความร้อนที่สอดคล้องกับ PHB มาตรฐาน จึงยืนยันได้ว่าเป็นพอลิเมอร์ชนิด PHB ต่อมาเตรียมไมโครคริสตัลลีนเซลลูโลสและดัดแปรโครงสร้างทางเคมีด้วยปฏิกิริยาเอสเทอริฟิเคชันโดยใช้บิวทิริลคลอไรด์เป็นสารดัดแปรพบว่าไมโครคริสตัลลีนเซลลูโลสบิวทิเรตมีการเปลี่ยนแปลงของหมู่ฟังก์ชันเนื่องจากมีการแทนที่ของสายโซ่อะลิฟาติกในหมู่ไฮดรอกซิล มีขนาดของอนุภาคที่ใหญ่ขึ้นและสามารถละลายได้ในตัวทำละลายคลอโรฟอร์ม จากนั้นเตรียมแผ่นฟิล์มวัสดุเชิงประกอบระหว่าง PHB และไมโครคริสตัลลีนเซลลูโลสบิวทิเรต โดยแปรผันอัตราส่วนของไมโครคริสตัลลีนเซลลูโลสบิวทิเรตพบว่าแผ่นฟิล์มวัสดุเชิงประกอบมีการเปลี่ยนแปลงสมบัติทางความร้อนและมีการเพิ่มขึ้นของค่าความทนแรงดึงและการยืดตัว ณ จุดขาดของแผ่นฟิล์มวัสดุเชิงประกอบชีวภาพที่อัตราส่วน 95 ต่อ 5 และ 90 ต่อ 10 หลังการทดสอบการย่อยสลายทางชีวภาพในดินของแผ่นฟิล์มวัสดุเชิงประกอบชีวภาพพบว่าแผ่นฟิล์มวัสดุเชิงประกอบชีวภาพยังคงมีความสามารถในการย่อยสลายทางชีวภาพ

Trends In Antibiotic Resistance And Correlations Of Antibiotic Use And Antibiotic Resistance In A Small Hospital In El Paso, Texas 2013-2015, Christopher Olivas

Open Access Theses & Dissertations

Antibiotic resistance is a serious public health threat, primarily, resulting from the excess and inappropriate use of antibiotics. Antibiotic resistance and antibiotic consumption trends may differ along the U.S-Mexico border from the rest of the U.S. due to geographical and cultural differences unique to the border region. The objectives of this study were: 1.) To examine the trends in antibiotic resistance among E. coli, ESBL producing E. coli, P. aeruginosa, S. aureus, and MRSA over a 3-year period (2013, 2014, 2015) in a U.S.-Mexico border area hospital; 2.) To examine the trends in antibiotic consumption among aztreonam, cefazolin, cefepime, ceftriaxone, …

Impacts Of Trace Metal Pollution, Urbanization And Aquifer Recharge On Spokane River Macroinvertebrates, Carolyn K. Connelly

EWU Masters Thesis Collection

This study analyzed macroinvertebrate communities of the Spokane River to determine: 1) accumulation of toxic trace metals in macroinvertebrate tissue, 2) effects of aquifer recharge, and 3) impact of urbanization. I predicted that aquifer inflows of cold, clean water would mitigate effects of pollution, and that reaches above the City of Spokane would be less negatively affected by urbanization; both were unsupported. I also predicted that effects of toxic trace metals would decrease within distance downstream; this prediction was supported. I sampled 12 riffles of the Spokane River between the Washington/Idaho border and Riverside State Park in late summer 2010. …

The Bi-Directional Relationship Between Gut Microbiota And Autoimmunity, Trevor O. Kirby

EWU Masters Thesis Collection

Humans serve as a major reservoir for a vast number of microbiota. These microbes have evolved symbiotic relationships with humans due to their close proximity with their host. As a result, the immune system adapts to the microbiota thus modulating immunological function. Autoimmunity is a state in which there are aberrant immune responses produced against host tissue. Intestinal bacteria are directly impacted by instances of inflammation brought on by autoimmunity. The complicated nature between autoimmunity and bacterial modulation demonstrates a bi-directional relationship. Here, we utilize experimental autoimmune encephalomyelitis, a model for multiple sclerosis, to explore the bi-directional relationship that disease …

Monitoring The Influx Of Marine Derived Nitrogen And Characterizing Soil Food Webs Of Riparian Zones Of The Elwha River Watershed, Wa, Usa., Wendal R.H. Kane

EWU Masters Thesis Collection

Nitrogen is often the most limiting nutrient to productivity in terrestrial ecosystems, and can have large effects on ecosystem processes. Two sources of nitrogen to Pacific Northwest riparian areas are marine derived nitrogen (MDN) via anadromous pacific salmon and symbiotic nitrogen fixation via Alnus rubra. The recent removal of two large dams on the Elwha River, WA, opened up ~60 km of previously inaccessible river habitat for pacific salmon. I used naturally abundant stable nitrogen isotopes (denoted as ‰ δ15N) to establish baseline data to monitor the influx of MDN to riparian zones of Elwha River tributaries, post dam removal. …

Discovery Of New Antimicrobial Options And Evaluation Of Aminoglycoside Resistance Enzyme-Associated Resistance Epidemic, Selina Y. L. Holbrook

Theses and Dissertations--Pharmacy

The extensive and sometimes incorrect and noncompliant use of various types of antimicrobial agents has accelerated the development of antimicrobial resistance (AMR). In fact, AMR has become one of the greatest global threat to human health in this era. The broad-spectrum antibiotics aminoglycosides (AGs) display excellent potency against most Gram-negative bacteria, mycobacteria, and some Gram-positive bacteria, such as Staphylococcus aureus. The AG antibiotics amikacin, gentamicin, kanamycin, and tobramycin are still commonly prescribed in the U.S.A. for the treatment of serious infections. Unfortunately, bacteria evolve to acquire resistance to AGs via four different mechanisms: i) changing in membrane permeability to …

Pcb Disruption Of Gut And Host Health: Implications Of Prebiotic Nutritional Intervention, Jessie Baldwin Hoffman

Theses and Dissertations--Pharmacology and Nutritional Sciences

Exposure to environmental pollutants poses numerous risk factors for human health, including increasing incidence of cardiovascular disease and diabetes. Persistent organic pollutants, such as polychlorinated biphenyls (PCBs) have been strongly linked to the development of these chronic inflammatory diseases and the primary route of exposure is through consumption of contaminated food products. Thus, the gastrointestinal tract is susceptible to the greatest levels of these pollutants and is an important facet to study.

The first two hypotheses of this dissertation tested that exposure to PCBs disrupts gut microbiota directly (in vitro) and within a whole body system. PCB exposure …

Identifying Mechanisms Of Host Plant Specialization In Aphis Craccivora And Its Bacterial Symbionts, Thorsten Hansen

Theses and Dissertations--Entomology

Many insects form close relationships with microbial symbionts. Insect symbionts can provide novel phenotypes to their hosts, including influencing dietary breadth. In the polyphagous cowpea aphid, Aphis craccivora, the facultative symbiont Arsenophonus improves aphid performance on one host plant (locust), but decreases performance on other plants. The goal of my thesis was to investigate the mechanism by which Arsenophonus facilitates use of locust. First, I assembled an Aphis craccivora-Arsenophonus-Buchnera reference transcriptome to conduct RNAseq analysis, comparing gene expression in aphids feeding on locust and fava, with and without Arsenophonus infection. Overall, few transcripts were differentially …