Bacteriology Commons^™

Identifying Essential Viral Genes Through Genomic Engineering, Amber Carroll

Mahurin Honors College Capstone Experience/Thesis Projects

Bacteria developed resistance to penicillin a mere four years after the groundbreaking antibiotic was first mass produced (Casadevall, 2010). Since then, the development of antibiotic-resistant bacteria has steadily risen, causing millions of difficult to treat infections annually. The challenge is to identify ways to combat these menacing microbes. Bacteriophages are viruses that infect bacteria and can potentially be used to eliminate deadly antibiotic-resistant bacteria. The number of sequenced bacteriophage genomes has increased tremendously over the past 10 years, but little is known about the function of most bacteriophage genes. The purpose of this study was to expand our understanding of …

The Role Of Manganese In Streptococcus Sanguinis, Tanya M. Puccio

Theses and Dissertations

Streptococcus sanguinis is primarily associated with oral health as a commensal bacterium. As an opportunistic pathogen, S. sanguinis is capable of colonizing heart valve vegetations, leading to the disease infective endocarditis. Previous studies from our lab have identified the high-affinity manganese transporter SsaACB as important for endocarditis virulence. The impact that manganese depletion has on S. sanguinis had never been evaluated and a secondary manganese transporter has not been identified. Thus, we employed the use of a fermentor to control large-scale growth over time and depleted manganese in an ΔssaACB mutant using a metal chelator, EDTA. The changes in …

High-Throughput Two-Stage Dereplication Of Cave Bacteria To Discover Novel Antibiotic Compounds, Alexander Archey

Williams Honors College, Honors Research Projects

Since their discovery over a century ago, antibiotics have been a staple of combating infectious diseases. However, bacteria develop resistance to antibiotics through a variety of mechanisms. Efforts to identify new antibiotics often fail by discovering already-known antibiotics, or failing to synthesize new antibiotics that are safe for clinical use. The aim of this research was to dereplicate bacteria- to screen for antibiotic production in- normally isolated in cave ecosystems. Using two new technologies, the Antibiotic Resistance Platform (ARP) and a data acquisition and bioinformatics technique (IDBac), my dereplicating method allowed high throughput of bacterial screening for antibiotics. In this …

Helicobacter Pylori Gene Regulation By Virulence Region Located Srnas, Veronica Janette Albrecht

EWU Masters Thesis Collection

Approximately 50% of the human population is infected with Helicobacter pylori, which can lead to gastrointestinal diseases such as ulcers and gastric adenocarcinoma. Helicobacter pylori strains are genetically variable, and some contain a DNA region called the cytotoxin associated gene pathogenicity island (cagPAI) that encodes virulence factors. Gastrointestinal disease associated with H. pylori are more likely to occur in infections with cagPAI positive strains. Helicobacter pylori has few known transcriptional regulators, but still must regulate expression to survive a constantly changing environment. A mechanism to facilitate this regulation was revealed in a transcriptome analysis conducted by Sharma et al. (2010) …

Characterization Of Helicobacter Pylori Srnas Hpnc2525, Hpnc2600, And Hpnc2645, Brandon M. Flatgard

EWU Masters Thesis Collection

Helicobacter pylori is a common microaerophilic gram-negative bacterium that infects approximately 50% of the human population. Although all H. pylori infections result in inflammation of the gastric epithelium, only 10-15% of infections are symptomatic and progress to severe gastric diseases such as gastric and duodenal ulcers, MALT lymphoma and gastric cancer. Different disease outcomes are due in part to genetic variations among H. pylori strains. Helicobacter pylori strains with a genomic region called the cytotoxin-associated pathogenicity island (cagPAI) are associated with an increased risk of severe disease. The cagPAI region encodes a type IV secretion system that transports the CagA …

Characterization Of The Physical And Chemical Effect Of Membrane Disruption And Protein Inhibiting Treatments On E. Coli, Khadijah Wright

Honors Undergraduate Theses

The increase in antibacterial resistance has placed the issue of microbial multi-drug resistance on a global stage (Gurunathan, 2019). This issue poses a threat to human and animal health as well as to the environment (Aslam et al., 2018). It affects not only the efficacy of treatment but also how those treatments are conducted (Friedman, Temkin, & Carmeli, 2016). As a result of this ongoing threat, new treatments that have potent effects on bacteria are necessary. One scientific response to this issue has been the development of multifunctional nanoparticles (NPs)(H. Wang et al., 2018). NPs have the ability to be …

Interaction Of Streptomyces Closely Associated With Bacillus In Nitrogen-Limiting Conditions, Aminya Baniya

Electronic Theses and Dissertations

Biological Nitrogen Fixation is the process of conversion of atmospheric dinitrogen into ammonia which is performed by symbiotic as well as free-living diazotrophic bacteria. A previous project to isolate free-living nitrogen fixing bacteria from a natural prairie yielded Streptomyces which grew on nitrogen free medium. Genome sequencing of three isolates revealed the presence of a second 16S rRNA gene sequence aligning with Bacillus, however repeated streaking only yielded Streptomyces colonies. The aim of this research was to characterize the interaction of three Streptomyces isolates that grow under nitrogen-free conditions, and appeared to be associated with Bacillus. The separation of Bacillus …

Evaluation Of Rhodococcus Equi Susceptibility To Silver Nanoparticle Antimicrobials, Elizabeth Boudaher

Theses and Dissertations--Veterinary Science

Rhodococcus equi is a significant cause of pneumonia in foals and immunocompromised humans. Antimicrobial resistance among R. equi isolates has developed as a consequence of inappropriate stewardship and bacterial evolution, leading to an increased rate of treatment failures that typically result in foal fatality. In the current study, we evaluated the efficacy of antimicrobial silver nanoparticle (AgNP) complexes in controlling R. equi growth. Previous studies characterizing AgNP-induced antibacterial effects in other Gram-positive pathogens led us to hypothesize that silver nanoparticle antimicrobials impact R. equi viability and intracellular replication. We therefore investigated the effect of silver nanoparticle complexes on R. equi …

The Effects Of Staining Cyanobacteria With Sytoxgreen After Lysis By Freeze-Thaw And Lysis By Ethanol, Samantha Galambos

Williams Honors College, Honors Research Projects

The purpose of this project is to find the effects of staining toxic cyanobacteria with SYTOXGreen after lysis by freeze-thaw and lysis by ethanol. This project will focus on two strains of toxic cyanobacteria known as Aphanizomenon - A. flos-aquae and Planktothrix - P. agardhii. The live and dead cells are observed under blue and red fluorescent light to show the effectiveness of each lysis. It is important that this topic is researched because it is significantly affecting our waterways and sometimes drinking water. We often see that you cannot swim in Lake Erie due to algae, more specifically, these …

The Antimicrobial Activity Of Silicon Copper Nanoparticles, Angela Mangano

Sustainability Research & Creative Activities Grants Reports

Excessive overuse of antibiotics has led to the emergence of mutations within bacteria that result in drug resistance. In an effort to combat the expanding issue of drug resistance, nanoparticles' bactericidal capabilities are being researched as an alternative to antibiotics (Beyth, 2015). In this paper, research to explore a novel silicon copper nanoparticle's antimicrobial capabilities will be discussed. The novel nanoparticle was developed by West Chester University professor, Dr. Kolasinski. The specific research goals were to determine the time and dose dependency of the nanoparticles and investigate the antimicrobial spectrum of activity against Gram-positive bacteria, Gram-negative bacteria, and viruses. Gram-positive …

Genetic Analysis Of A Novel Ftsk Homolog, Hfka, In Streptomyces Coelicolor Development-Associated Chromosome Segregation, Sumedha Sethi

Electronic Theses and Dissertations

A quintessential phenomenon occurring during prokaryotic development is accurate segregation of the replicated genomes into the daughter cells. Key energy-dependent processes like chromosome condensation and subcellular partitioning of the genomes are driven by conserved proteins like SMC, ParB, FtsK. During its complex developmental cycle, Streptomyces coelicolor segregates its genomes into chains of unicellular spores when its multigenomic syncytial aerial hyphae undergo division.

A novel ftsK-like gene, hfkA (Homolog of FtsK protein A), was examined for function and localization during development-associated chromosome segregation. Individual deletions did not affect segregation, but a ΔhfkA ΔftsK mutant exhibited 8% anucleate …

Genetic And Biochemical Analysis Of A Conserved, Multi-Gene System Regulation Spore-Associated Proteins In Streptomyces Coelicolor, Joseph Sallmen

Electronic Theses and Dissertations

Streptomyces coelicolor is a Gram positive, filamentous soil dwelling bacterium that exhibits a complex life cycle including the transition from a vegetative mycelium to a sporulating, aerial mycelium. Early genetic studies identified two classes of genes that resulted in developmental blocks, bald and white. The bald (bld) phenotype occurs when colonies cannot produce aerial hyphae. White (whi) colonies exhibit incomplete sporulation and/or loss of production of the concurrently produced grey pigment. While some of the original mutants have been explored, the developmental functions of many of the identified genes are not well understood. Of particular interest …

The Potential For Dickeya Dianthicola To Be Vectored By Two Common Insect Pests Of Potatoes, Jonas K. Insinga

Electronic Theses and Dissertations

Dickeya dianthicola (Samson) causing blackleg and soft rot was first detected in potatoes grown in Maine in 2014. Previous work has suggested that insects, particularly aphids, may be able to vector bacteria in this genus between plants, but no conclusive work has been done to confirm this theory. In order to determine whether insect-mediated transmission is likely to occur in potato fields, two model potato pests common in Maine were used: the Colorado potato beetle (Leptinotarsa decimlineata Say) and the green peach aphids (Myzus persicae Sulzer). Olfactometry and recruitment experiments evaluated if either insect discriminates between infected and …

Acid Resistance Mechanisms In Staphylococcus Aureus, Chunyi Zhou

Theses & Dissertations

Staphylococcus aureus is a leading cause of opportunistic infections in community and health care settings. To thrive in a great variety of environments, S. aureus has developed the capability of tolerating temporary pH changes, as well as resisting constant acid stress. To evaluate the impact of strong and weak acid stress on S. aureus, growth patterns of JE2 were monitored when cultured in chemically defined media (CDM) at various pH in the presence of hydrochloric acid (HCl), acetic acid, and lactic acid. Our results showed that S. aureus responds to strong and weak acids in different manners. S. aureus …

The Antimicrobial Activity And Cellular Targets Of Plant Derived Aldehydes And Degradable Pro-Antimicrobial Networks In Pseudomonas Aeruginosa, Yetunde Adewunmi

Dissertations

Essential oils (EOs) are plant-derived products that have been long exploited for their antimicrobial activities in medicine, agriculture, and food preservation. EOs represent a promising alternative to conventional antibiotics due to the broad-range antimicrobial activity, low toxicity to human commensal bacteria, and the capacity to kill microorganisms without promoting resistance. Despite the progress in the understanding of the biological activity of EOs, many aspects of their mode of action remain inconclusive. The overarching aim of this work was to address these gaps by studying molecular interactions between antimicrobial plant aldehydes and the opportunistic human pathogen Pseudomonas aeruginosa. We initiated …

Growth Phase Proteomics Of The Heterotrophic Marine Bacterium Ruegeria Pomeroyi, Dasha Krayushkina, Emma Timmins-Schiffman, Jessica Faux, Damon H. May, Michael Riffle, H. Rodger Harvey, Brook L. Nunn

OES Faculty Publications

The heterotrophic marine bacterium, Ruegeria pomeroyi, was experimentally cultured under environmentally realistic carbon conditions and with a tracer-level addition of ¹³C-labeled leucine to track bacterial protein biosynthesis through growth phases. A combination of methods allowed observation of real-time bacterial protein production to understand metabolic priorities through the different growth phases. Over 2000 proteins were identified in each experimental culture from exponential and stationary growth phases. Within two hours of the ¹³C-labeled leucine addition, R. pomeroyi significantly assimilated the newly encountered substrate into new proteins. This dataset provides a fundamental baseline for understanding growth phase differences in molecular …

Species Richness And Ecological Diversity Of Myxomycetes And Myxomycete-Like Organisms In The Tropical Forests Of Brazil, Isadora Lima Coelho

Graduate Theses and Dissertations

Tropical rain forests cover less than two percent of Earth's surface, yet they sustain the greatest diversity of living organisms on the planet. Tropical rain forests cover nearly 73% of the Brazilian territory and besides harboring some of the most biodiverse ecosystems on the planet, this vast area also houses about 83% of the Brazilian population. Approximately 175 million people live in urban and rural areas with fragments of coverage of these biomes which contributes to the loss of biodiversity that rapidly increases over the years. Furthermore, the majority of the taxonomic and ecological efforts to describe and protect the …

Exploring Secondary Structure In Bacteriophage Programmed Frameshift Elements, Samuel Okabayashi, Sean Mcclory

HON499 projects

Bacteriophages are viruses that infect bacteria and reproduce using host bacterial components. Part of the bacteriophage reproduction is assembly of the tail complex, which requires two assembly chaperone (TAC) proteins. In many phages the TAC’s are produced from a single gene through a non-canonical process called programmed translational frameshifting (PTF). The SEA-PHAGES program has produced hundreds of TAC genes that are accessible through phagesdb, a database of sequenced and annotated phage genomes. The sequences for the TAC gene were gathered from phagesdb and analyzed using ClustalOmega; a multiple sequence alignment (MSA) tool which revealed several positions where total conservation was …

The Role Of Multidrug Resistance Regulators Mara, Soxs, Rob And Rama In Regulating Virulence Traits In Salmonella Enterica, Srinivas Thota

Dissertations

Enteric pathogens sense numerous signals specific to the anatomical location in the intestine and integrate them with the complex regulatory networks to temporally and spatially regulate their virulence genes. MarA, SoxS, Rob and RamA are homologous transcription factors that belong to AraC family of proteins in Salmonella enterica that primarily were thought to be involved in rendering antibiotic resistance to bacteria by up regulating efflux pumps and down regulating outer membrane porins. The fact that these transcription factors respond to the same intestinal compounds that regulate virulence genes in Salmonella motivated us to look for other roles of these transcription …

Mechanism Of Neutrophil Homeostasis And Immunity In Pneumonia And Sepsis, Sagar Paudel

LSU Doctoral Dissertations

Severe bacterial pneumonia and septicemia are pressing health problems. A better understanding of cellular and molecular players of neutrophil immunity and homeostasis in bacterial pneumonia and sepsis is critical for inspiring novel therapeutics. Chemokine CXCL1 is a widely secreted neutrophil attractant and Nod-like receptor (NLRC4) is commonly expressed cytoplasmic pathogen sensor in hematopoietic compartments. How these innate mediators convert pathogen signals into molecular cues of immune response in context of Gram-positive bacterial pneumonia and septicemia largely remain unknown. Utilizing Cxcl1 gene deficient mice, we demonstrate CXCL1 regulates neutrophil influx, bacterial clearance, and host survival in pneumococcal pneumonia-derived sepsis. Furthermore, Cxcl1 …