Organisms Commons^™

The Role Of Nutrient Deficiency In Persister Cell Formation- A Morphological Study, Ryan Newman, Emajoy Rains, Isaac Young, Victor M. Jimenez

Annual Research Symposium

No abstract provided.

Bacterial Two-Hybrid Systems Evolved: Innovations For Protein-Protein Interaction Research, Rebecca M. Richardson, Steven M. Pascal

Chemistry & Biochemistry Faculty Publications

Bacterial two-hybrid (B2H) systems offer a versatile platform for detecting protein-protein interactions (PPIs) in vivo. Originally developed to study bacterial transcriptional regulators, these systems have evolved to support a wide range of applications, including interaction mapping, domain analysis, and high-throughput screening. This review surveys the development and expansion of B2H systems across diverse biological contexts. We highlight technical considerations, platform-specific innovations, and recent adaptations that extend the utility of B2H systems in both prokaryotic and eukaryotic protein interaction research environments. By comparing different B2H variants and discussing their integration with complementary approaches, we provide a framework for leveraging these …

Dengue Virus Modulates Critical Cell Cycle Regulatory Proteins In Human Megakaryocyte Cells, Swarnendu Basak, Shovan Dutta, Supreet Khanal, Girish Neelakanta, Hameeda Sultana

Biological Sciences Faculty Publications

Suppression of human megakaryocytes by dengue virus (DENV) infection significantly reduces the platelet count that eventually leads to thrombocytopenia, severe dengue and death. To understand DENV interactions with megakaryocytes, we investigated the cell cycle in leukemic human megakaryocytic in vitro cell line (MEG-01 cells). Megakaryocytes are known for complex endomitotic cell cycle leading to their polyploidy state. Our study shows that DENV uses these polyploid cells for its replication. Understanding the modulation of DENV-mediated cell cycle regulation in megakaryocytes is therefore highly important. We show that DENV2 (serotype 2) infection significantly modulates cell cycle signaling. Our protein profile microarray data …

Analysis Of Antibiotic Sensitivity Patterns In Pasteurellaceae Family Isolates: A Microbial And Molecular Investigation, Jillian Barron

Honors Scholar Theses

Bacteria in the Pasteurellaceae family are known to cause disease in both human and animal species. Like all species of bacteria, the pathogens in the Pasteurellaceae family evolve and acquire antimicrobial-resistant traits. Antimicrobial resistance of bacteria is a significant public health concern, as treatment of resistant pathogens becomes more difficult, if not impossible, with current medical capabilities. In this project, phenotypic and genotypic analyses were performed on Pasteurellaceae family isolates sourced from the Connecticut Veterinary Medical Diagnostic Laboratory. Phenotypic antibiotic sensitivity patterns of each isolate were assessed against a panel of antibiotics through a Kirby-Bauer disk diffusion test. Disk diffusion …

Investigating The Role Of The Gut Microbiota On Immune Checkpoint Inhibitor-Mediated Colitis, Taylor Halsey, Robert Jenq

Dissertations and Theses (Open Access)

Immune checkpoint inhibitors (ICIs) have been revolutionary in the fight against cancer by recruiting the host immune system as an agent for attack on malignant cells. Unfortunately, immune-related adverse events (irAEs), including ICI-mediated colitis (IMC), are common side effects that result from immune cell mediated damage on healthy tissues. Recent studies have highlighted a role for the gut microbiota in modulating ICI-mediated anti-tumor responses, but less is known regarding how the gut microbiota may impact on irAEs. Considering that the gastrointestinal tract harbors thousands of unique microbial species, many of which are known to modulate the immune system, microbes and …

The Oral-Microbiome-Brain Axis: A Thorough Review On The Relationship Between Periodontitis And Alzheimer’S Disease And A Proposed Innovative Application Of Biomagnetism As A Means Of Alternative Therapy., Taha Al Hassan, Noah Al-Hassan, Maria Quiñones-Peña, Juan Lopez-Alvarenga, Seratna Guadarrama-Beltran

MEDI 9331 Scholarly Activities Clinical Years

The relationship between periodontitis and Alzheimer's disease (AD) has garnered significant attention due to the potential influence of chronic oral inflammation on neurodegenerative processes. Our hypothesis is supported by the oral-microbiome-brain axis and highlights the possibility that chronic periodontitis contributes to cognitive decline by promoting systemic inflammation and neuroinflammation, mediated by specific pathogenic microorganisms within the oral microbiome. Our findings reveal a strong association between elevated levels of Porphyromonas gingivalis and Treponema denticola, red complex bacteria, and markers of systemic inflammation, such as C-reactive protein (CRP) and pro-inflammatory cytokines. Additionally studies have demonstrated that beta amyloid plaque in rat …

Plants As Vectors For Environmental Prion Transmission, Christina M Carlson, Samuel Thomas, Matthew W Keating, Paulina Soto, Nicole M Gibbs, Haeyoon Chang, Jamie K Wiepz, Annabel G Austin, Jay R Schneider, Rodrigo Morales, Christopher J Johnson, Joel A Pedersen

Faculty, Staff and Student Publications

Prions cause fatal neurodegenerative diseases and exhibit remarkable durability, which engenders a wide array of potential exposure scenarios. In chronic wasting disease of deer, elk, moose, and reindeer and in scrapie of sheep and goats, prions are transmitted via environmental routes and the ability of plants to accumulate and subsequently transmit prions has been hypothesized, but not previously demonstrated. Here, we establish the ability of several crop and other plant species to take up prions via their roots and translocate them to above-ground tissues from various growth media including soils. We demonstrate that plants can accumulate prions in above-ground tissues …

Discovering Novel Polyextremotolerant Fungi And Determining Their Ecological Role Within The Biological Soil Crust Consortium, Erin C. Carr

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

The ecological niche of polyextremotolerant fungi within oligotrophic ecosystems such as biological soil crusts has not yet been determined. These fungi persist in locations where nutrients are depleted while simultaneously surrounded by autotrophic microbes such as algae and cyanobacteria. Yet it has not been shown that they are engaging in any exchange of nutrients the way lichens do. However, there is seemingly no other way for these fungi to obtain vital nutrients, such as carbon or nitrogen, other than from these microbes. Here we have isolated polyextremotolerant fungi from cold desert biological soil crusts which are a microbial biofilm that …

Examining The Pulmonary Response To Repeated Vishniacozyma Victoriae Exposure And Its Association With Allergic Airway Disease, Rachael Erin Rush

Graduate Theses, Dissertations, and Problem Reports (ETD)

Allergic airway diseases such as asthma continue to increase in incidence in industrialized nations like the United States. These diseases are complex inflammatory processes involving numerous cells and mediators and are strongly influenced by fungal exposures. Recent developments in fungal detection methods have highlighted the contribution of Basidiomycota yeast species in indoor environments such as Vishniacozyma (syn. Cryptococcus) victoriae. However, despite the high levels of this yeast detected in indoor environments, very little is known about it or its role in respiratory morbidity. V. victoriae is phylogenetically similar to pathogenic Cryptococcus neoformans but lacks a capsule and is …

Deciphering The Mechanisms Of Alcaligenes Faecalis’ Inhibition Of Staphylococcus Aureus And Synergism With Antibiotics, Cortlyn Holdren

Undergraduate Honors Theses

Staphylococcus aureus has developed resistance to several antibiotics including vancomycin, which is often used as a “last resort” treatment. There is an ever-increasing need to develop novel antimicrobial treatments to combat S. aureus and other drug resistant bacteria. Microorganisms are most often found in polymicrobial communities where they either exhibit synergistic or antagonistic relationships. Competition between microorganisms can lead to the discovery of new antimicrobial targets as the specific mechanisms of resistance are elucidated. In addition, synergistic treatments are being evaluated for their combined effect and potential to decrease the concentration of drugs needed, and thus the side effects also. …

Understanding Human Astrovirus From Pathogenesis To Treatment, Virginia Hargest

Theses and Dissertations (ETD)

While human astroviruses (HAstV) were discovered nearly 45 years ago, these small positive-sense RNA viruses remain critically understudied. These studies provide fundamental new research on astrovirus pathogenesis and disruption of the gut epithelium by induction of epithelial-mesenchymal transition (EMT) following astrovirus infection. Here we characterize HAstV-induced EMT as an upregulation of SNAI1 and VIM with a down regulation of CDH1 and OCLN, loss of cell-cell junctions most notably at 18 hours post-infection (hpi), and loss of cellular polarity by 24 hpi. While active transforming growth factor- (TGF-) increases during HAstV infection, inhibition of TGF- signaling does not hinder EMT induction. …

Antifungal Defense Molecules From Bacterial Symbionts Of North American Trachymyrmex Ants, Georgia Scherer

CMC Senior Theses

Defensive symbioses, in which microbes provide molecular defenses for an animal host, hold great potential as untapped sources of therapeutically useful antibiotics. Fungus-growing ants use antifungal defenses from bacterial symbionts to suppress pathogenic fungi in their nests. Preliminary chemical investigations of symbiotic bacteria from this large family of ants have uncovered novel antifungal molecules with therapeutic potential, such as dentigerumycin and selvamicin.

In this study, the bacterial symbionts of North American Trachymyrmex fungus-growing ants are investigated for antifungal molecules. Plate-based bioassays using ecologically-relevant fungal pathogens confirmed that these bacteria have antifungal activity. In order to purify and identify the antifungal …

A Rapid Viability And Drug‑Susceptibility Assay Utilizing Mycobacteriophage As An Indicator Of Drug Susceptibilities Of Anti‑Tb Drugs Against Mycobacterium Smegmatis Mc2 155, Gillian Catherine Crowley, Jim O'Mahony, Aidan Coffey, Riona G. Sayers, Paul D. Cotter

Department of Biological Sciences Publications

Background: A rapid in-house TM4 mycobacteriophage-based assay, to identify multidrug resistance against various anti-tuberculosis drugs, using the fast-growing Mycobacterium smegmatis mc² 155 in a microtiter plate format was evaluated, based on phage viability assays. Methods: A variety of parameters were optimized before the study including the minimum incubation time for the drugs, phage and M. smegmatis mc² 155 to be in contact. An increase in phage numbers over 2 h was indicative that M. smegmatis mc² 155 is resistant to the drugs under investigation, however when phage numbers remained static, M. smegmatis mc² 155 found to …

Emergence Of The L Phenotype In Group B Streptococci In The South Of Ireland, Katherine Hayes, Lesley Cotter, L. Barry, Fiona O'Halloran

Department of Biological Sciences Publications

Group B Streptococcal isolates (n = 235) from the South of Ireland were characterised by serotyping, antimicrobial susceptibility and determination of the phenotypic and genotypic mechanisms of resistance. Resistance to erythromycin and clindamycin was observed in 21·3% and 20·4% of the total population, respectively. The c-MLSB phenotype was the most common phenotype detected (62%), with ermB being the predominant genetic determinant, present in 84% of resistant isolates. The rare L phenotype was observed in 2·9% (n = 7) of isolates, four of which harboured the lsaC gene responsible for clindamycin resistance. Serotypes Ia, III and II were the most common …

Structure-Function Investigation Of Proteins Involved In Cellulose Biosynthesis By Escherichia Coli, Thomas Brenner

Theses and Dissertations (Comprehensive)

Bacteria thrive within multicellular communities called biofilms consisting of a self-produced matrix. Biofilm matrices improve bacterial adherence to surfaces while creating a barrier from host immune responses, disinfectants, antibiotics and other environmental factors. Persistent colonization by the widely distributed pathogens, Escherichia coli and Salmonella spp., has been linked to production of biofilms composed of the exopolysaccharide cellulose. Cellulose-containing biofilms are also important to Acetobacter, Sarcina, Rhizobium and Agrobacterium species to form symbiotic and pathogenic interactions. In Enterobacteriaceae, two operons (bcsABZC and bcsEFG) are proposed to encode for proteins that form a cellulose biosynthetic complex that spans the …

Comparative Genomic Analysis Of Two Serotype 1/2b Listeria Monocytogenes Isolates From Analogous Environmental Niches Demonstrates The Influence Of Hypervariable Hotspots In Defining Pathogenesis, Aidan Casey, Kieran Jordan, Aidan Coffey, Edward M. Fox, Olivia Mcauliffe

Department of Biological Sciences Publications

The vast majority of clinical human listeriosis cases are caused by serotype 1/2a, 1/2b, 1/2c, and 4b isolates of Listeria monocytogenes. The ability of L. monocytogenes to establish a systemic listeriosis infection within a host organism relies on a combination of genes that are involved in cell recognition, internalization, evasion of host defenses, and in vitro survival and growth. Recently, whole genome sequencing and comparative genomic analysis have proven to be powerful tools for the identification of these virulence-associated genes in L. monocytogenes. In this study, two serotype 1/2b strains of L. monocytogenes with analogous isolation sources, but …

Laboratory Exercises In Microbiology: Discovering The Unseen World Through Hands-On Investigation, Joan Petersen, Susan Mclaughlin

Open Educational Resources

The exercises in this laboratory manual are designed to engage students in hand-on activities that reinforce their understanding of the microbial world. Topics covered include: staining and microscopy, metabolic testing, physical and chemical control of microorganisms, and immunology. The target audience is primarily students preparing for a career in the health sciences, however many of the topics would be appropriate for a general microbiology course as well.

Changing Diagnostic Methods And Increased Detection Of Verotoxigenic Escherichia Coli, Ireland, Thomas Rice, Noreen Quinn, Roy D. Sleator, Brigid Lucey

Department of Biological Sciences Publications

The recent paradigm shift in infectious disease diagnosis from culture-based to molecular-based approaches is exemplified in the findings of a national study assessing the detection of verotoxigenic Escherichia coli infections in Ireland. The methodologic changes have been accompanied by a dramatic increase in detections of non-O157 verotoxigenic E. coli serotypes.

Optimization Of A Genomic Editing System Using Crispr/Cas9-Induced Site-Specific Gene Integration, Jillian L. Mccool Ms., Nick Hum, Gabriela G. Loots

STAR Program Research Presentations

The CRISPR-Cas system is an adaptive immune system found in bacteria which helps protect against the invasion of other microorganisms. This system induces double stranded breaks at precise genomic loci (1) in which repairs are initiated and insertions of a target are completed in the process. This mechanism can be used in eukaryotic cells in combination with sgRNAs (1) as a tool for genome editing. By using this CRISPR-Cas system, in addition to the “safe harbor locus,” ROSAβ26, the incorporation of a target gene into a site that is not susceptible to gene silencing effects can be achieved through few …

Wake Me When It's Over- Bacterial Toxin-Antitoxin Proteins And Induced Dormancy, Nathan P. Coussens, Dayle A. Daines

Biological Sciences Faculty Publications

Toxin-antitoxin systems are encoded by bacteria and archaea to enable an immediate response to environmental stresses, including antibiotics and the host immune response. During normal conditions, the antitoxin components prevent toxins from interfering with metabolism and arresting growth; however, toxin activation enables microbes to remain dormant through unfavorable conditions that might continue over millions of years. Intense investigations have revealed a multitude of mechanisms for both regulation and activation of toxin-antitoxin systems, which are abundant in pathogenic microorganisms. This minireview provides an overview of the current knowledge regarding type II toxin-antitoxin systems along with their clinical and environmental implications.

A Tail Of Two Phages: Genomic And Functional Analysis Of Listeria Monocytogenes Phages Vb_Lmos_188 And Vb_Lmos_293 Reveal The Receptor-Binding Proteins Involved In Host Specificity, Aidan Casey, Kieran Jordan, Horst Neve, Aidan Coffey, Olivia Mcauliffe

Department of Biological Sciences Publications

The physical characteristics of bacteriophages establish them as viable candidates for downstream development of pathogen detection assays and biocontrol measures. To utilize phages for such purposes, a detailed knowledge of their host interaction mechanisms is a prerequisite. There is currently a wealth of knowledge available concerning Gram-negative phage-host interaction, but little by comparison for Gram-positive phages and Listeria phages in particular. In this research, the lytic spectrum of two recently isolated Listeria monocytogenes phages (vB_LmoS_188 and vB_LmoS_293) was determined, and the genomic basis for their observed serotype 4b/4e host-specificity was investigated using comparative genomics. The late tail genes of these …

Draft Genome Sequences Of Six Different Staphylococcus Epidermidis Clones, Isolated Individually From Preterm Neonates Presenting With Sepsis At Edinburgh's Royal Infirmary, Paul Walsh, M. Bekaert, J. Carroll, T. Manning, B. Kelly, A. O'Driscoll, X. Lu, C. Smith, P. Dickinson, K. Templeton, P. Ghazal, Roy D. Sleator

Department of Biological Sciences Publications

Herein, we report the draft genome sequences of six individual Staphylococcus epidermidis clones, cultivated from blood taken from different preterm neonatal sepsis patients at the Royal Infirmary, Edinburgh, Scotland, United Kingdom.

Characterization And Quantification Of The Fungal Microbiome In Serial Samples From Individuals With Cystic Fibrosis, Sven D. Willger, Sharon L. Grim, Emily L. Dolben, Anna Shipunova, Thomas H. Hampton, Hillary G. Morrison, Laura M. Filkins, George A. O'Toole, Lisa A. Moulton, Alix Ashare, Mitchell L. Sogin, Deborah A. Hogan

Dartmouth Scholarship

Background: Human-associated microbial communities include fungi, but we understand little about which fungal species are present, their relative and absolute abundances, and how antimicrobial therapy impacts fungal communities. The disease cystic fibrosis (CF) often involves chronic airway colonization by bacteria and fungi, and these infections cause irreversible lung damage. Fungi are detected more frequently in CF sputum samples upon initiation of antimicrobial therapy, and several studies have implicated the detection of fungi in sputum with worse outcomes. Thus, a more complete understanding of fungi in CF is required. Results: We characterized the fungi and bacteria in expectorated sputa from six …

Enhanced Expression Of Codon Optimized Mycobacterium Avium Subsp. Paratuberculosis Antigens In Lactobacillus Salivarius, Christopher D. Johnston, John P. Bannatine, Rodney Govender, Lorraine Endersen, Daniel Pletzer, Helge Weingart, Aidan Coffey, Jim O'Mahony, Roy D. Sleator

Department of Biological Sciences Publications

It is well documented that open reading frames containing high GC content show poor expression in A+T rich hosts. Specifically, G+C-rich codon usage is a limiting factor in heterologous expression of Mycobacterium avium subsp. paratuberculosis (MAP) proteins using Lactobacillus salivarius. However, re-engineering opening reading frames through synonymous substitutions can offset codon bias and greatly enhance MAP protein production in this host. In this report, we demonstrate that codon-usage manipulation of MAP2121c can enhance the heterologous expression of the major membrane protein (MMP), analogous to the form in which it is produced natively by MAP bacilli. When heterologously over-expressed, antigenic determinants …

Transcriptome Analysis Of Listeria Monocytogenes Exposed To Biocide Stress Reveals A Multi-System Response Involving Cell Wall Synthesis, Sugar Uptake, And Motility, Aidan Casey, Edward M. Fox, Stephan Schmitz-Esser, Aidan Coffey, Olivia Mcauliffe, Kieran Jordan

Department of Biological Sciences Publications

Listeria monocytogenes is a virulent food-borne pathogen most often associated with the consumption of “ready-to-eat” foods. The organism is a common contaminant of food processing plants where it may persist for extended periods of time. A commonly used approach for the control of Listeria monocytogenes in the processing environment is the application of biocides such as quaternary ammonium compounds. In this study, the transcriptomic response of a persistent strain of L. monocytogenes (strain 6179) on exposure to a sub-lethal concentration of the quaternary ammonium compound benzethonium chloride (BZT) was assessed. Using RNA-Seq, gene expression levels were quantified by sequencing …

Phages Of Non-Diary Lactococci: Isolation And Characterization Of Phi L47, A Phage Infecting The Grass Isolate Lactococcus Lactis Ssp Cremoris Dpc6860, Daniel Cavanagh, Caitríona M. Guinane, Horst Neve, Aidan Coffey, R. Paul Ross, Gerald F. Fitzgerald, Olivia Mcauliffe

Department of Biological Sciences Publications

Lactococci isolated from non-dairy sources have been found to possess enhanced metabolic activity when compared to dairy strains. These capabilities may be harnessed through the use of these strains as starter or adjunct cultures to produce more diverse flavor profiles in cheese and other dairy products. To understand the interactions between these organisms and the phages that infect them, a number of phages were isolated against lactococcal strains of non-dairy origin. One such phage, ΦL47, was isolated from a sewage sample using the grass isolate L. lactis ssp. cremoris DPC6860 as a host. Visualization of phage virions by transmission electron …