Other Microbiology Commons^™

Promoting Extracellular Matrix Crosslinking In Synthetic Hydrogels, Marcos M. Manganare

Masters Theses

The extracellular matrix (ECM) provides mechanical and biochemical support to tissues and cells. It is crucial for cell attachment, differentiation, and migration, as well as for ailment-associated processes such as angiogenesis, metastases and cancer development. An approach to study these phenomena is through emulation of the ECM by synthetic gels constructed of natural polymers, such as collagen and fibronectin, or simple but tunable materials such as poly(ethylene glycol) (PEG) crosslinked with short peptide sequences susceptible to digestion by metalloproteases and cell-binding domains. Our lab uses PEG gels to study cell behavior in three dimensions (3D). Although this system fosters cell …

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 …

Variation In Microbiome Composition And Stability For A Vancomycin Treated Primary Sclerosing Cholangitis Patient With Ulcerative Colitis Compared With Controls, Alanna Dubrovsky

Symposium

The bacterial composition of the human intestines contributes to much more than just digestion. In the inflammatory, autoimmune conditions primary sclerosing cholangitis (PSC) and ulcerative colitis (UC), the microbiome may be, in some cases, a factor. To gain a better understanding of the composition and stability of the microbiome in a patient treated with vancomycin for PSC, terminal restriction fragment (TRF) analysis was performed on 13 controls and 1 patient, and 16s rRNA microbiome composition analysis was performed on 1 patient and 3 controls. Results showed similar levels of stability, with surprising differences in composition.

Role Of The C-Terminus Of The Catalytic Subunit Of Translesion Synthesis Polymerase Ζ (Zeta) In Uv-Induced Mutagensis, Hollie M. Siebler

Theses & Dissertations

Cellular DNA is under constant attack by endogenous and exogenous DNA damaging agents that threaten genome integrity. Unrepaired DNA lesions often stall replicative DNA polymerases and are bypassed by translesion synthesis (TLS) to prevent replication fork collapse. TLS mechanisms are lesion- and species-specific, with prominent roles of specialized DNA polymerases with relaxed active sites. After incorporation of nucleotide(s) across from the lesion, the distorted primer termini are typically extended by DNA polymerase ζ (Pol ζ). As a result, Pol ζ is responsible for most DNA damage-induced mutations. Mechanisms of sequential polymerase switches and regulation of Pol ζ access to DNA …

Characterization Of The Replication Of Coxsackievirus B3 With A Mutationally Disrupted Cre(2c) And The Use Of Creatinine-Hydrochloride As An Antibacterial Agent, Shane E. Smithee

Theses & Dissertations

Following natural or experimental infection, and in cell culture, coxsackie B virus (CVB) RNA can persist for weeks in the absence of CPE yet with detectable viral RNA. Earlier studies in our laboratory demonstrated that this persistence produced viral RNA with up to 49 nucleotide deletions at the 5’ genomic terminus, partially degrading the cloverleaf (or domain I), an RNA structure that is required for efficient viral replication. A cis-acting replication element (CRE) in the 2C protein coding region [CRE(2C)] templates the addition of two uridine residues to the virus-encoded RNA replication primer, VPg, prior to genomic replication. Because …

The Role Of Phosphatidylserine And Phosphatidylethanolamine In Candida Albicans Virulence, Sarah Elizabeth Davis

Doctoral Dissertations

In hospitalized patients with neutropenia, Candida albicans is the fourth leading cause of systemic bloodstream infections, which have a mortality rate of approximately 30 %. The phosphatidylserine synthase enzyme of C. albicans, Cho1p, appears to be a good drug target as a mutant lacking this enzyme (the cho1Δ/Δ [null mutant]) is avirulent in animal models of Candida infections and this enzyme is not conserved in humans. We discovered that the loss of phosphatidylserine (PS) synthesis affects C. albicans' expression of the Als3p adhesin, a virulence protein, and loss of PS synthesis also compromises the cell wall, causing increased …

Cmv Chemokines And Co-Infection: A Dissemination Plot That Peptides Can Foil, Pranay Dogra

Doctoral Dissertations

Human Cytomegalovirus (HCMV) is the leading cause of both non-hereditary mental retardation and hearing loss, and CMV infection/reactivation causes serious complications in transplant and immune compromised patients. Due to these issues, development of a CMV vaccine and/or therapeutics is required. To achieve this goal, it is necessary to gain a better understanding of CMV pathogenesis. Because of its coevolution with humans, HCMV has evolved genes with homology to human immune modulatory genes. Several of these genes help CMV establish a successful and lifelong infection within the host. An example is the viral CXC chemokine homolog UL146 gene (vCXCL-1). UL146 varies …

How Many Particles Are Present In The Air? Bioaerosol Detection Using An Air Particle Counter, Angie Pamela Rivera, Parag Vaishampayan

STAR Program Research Presentations

Relative cleanliness in terms of particle abundance in spacecraft assembly facilities is determined by particle counts carried out in clean rooms during resting conditions. Particle counters assess total particles and particle size distribution, but do not distinguish inert particles from biological particles, which may include bacterial spores that are resistant to standard cleanroom sterilization procedures. Current cleanroom certifications do not fully assess the effects of human presence on spacecraft contamination since humans are known symbionts to enumerate microorganisms and assessments are performed at rest when there is no human presence. In this study, contamination risks and bioburden in spacecraft assembly …

Identification Of Genes Required To Synthesize An Antibiotic-Like Compound From The Soil Bacterium Rhodococcus Sp. Mtm3w5.2, Amber L. Ward

Electronic Theses and Dissertations

Rhodococcus is a soil bacterium, member of the Actinobacteria, and a close relative of the prolific small molecule producer Streptomyces. Recent interest in Rhodococcus as an under investigated source of possible bioactive secondary metabolites is sparked by the discovery of many polyketide synthase and non-ribosomal peptide synthetase genes of unknown function from sequenced Rhodococcus genomes. Rhodococcus species strain MTM3W5.2 was recently shown to produce a strong inhibitory compound with activity against most strains of Rhodococcus and closely related genera. A goal of this investigation is to discover the gene(s) required to synthesize this inhibitory molecule. The engineered Rhodococcus …

Dissolution, Ocean Acidification And Biotic Extinctions Prior To The Cretaceous/Paleogene (K/Pg) Boundary In The Tropical Pacific, Serena Dameron

Masters Theses

The several million years preceding the Cretaceous/Paleogene (K/Pg) boundary has been the focus of many studies. Changes in ocean circulation and sea level, extinctions, and major volcanic events have all been documented for this interval. Important research questions these changes raise include the climate dynamics during the warm, but not hot, time after the decay of the Late Cretaceous greenhouse interval and the stability of ecosystems prior to the mass extinctions at the end-Cretaceous.

I document several biotic perturbations as well as changes in ocean circulation during the Maastrichtian stage of the latest Cretaceous that question whether the biosphere was …

Analysis Of Gene Expression During Embryonic Development In Mulberry Silkworm Bombyx Mori, Amit Singh, K. P. Gopinathan

Amit Singh

We have developed a method for dechorionation and devitellinization of the silkworm eggs without damage, to facilitate the analysis of gene expression during embryonic development of Bombyx mori. Making use of antibodies available from heterologous systems, the spatio-temporal expression patterns of peroxidase and proliferating cell nuclear antigen have been directly visualized in whole mount embryos at various stages of development without the need for generating transformed ·lines carrying specific reporter constructs. The B. mori system, previously unamenable for such studies, could thus serve as an attractive model for molecular analysis of insect development. The attention lavished on Drosophila melanogaster as …

Towards Bioregenerative Life Support For Extended Human Exploration: Experiment Development For Testing The Fitness Of Algae In Space, Audrey Fry, R. Craig Everroad, Jessica E. Koehne, Thomas E. Murphy, Brad M. Bebout

STAR Program Research Presentations

Microbes such as algae and bacteria are promising candidates for supporting extended human space travel, as they are robust sources of food, fuel, waste cycling, and oxygen production. Growing microbes on membranes reduces the mass and water demands of a bioreactor system, both of which are important considerations in space travel. The European Modular Cultivation System (EMCS) on the International Space Station (ISS) provides an ideal opportunity to test the effects of microgravity and other aspects of the space environment on algal growth on membranes. This project aims to find optimal growing conditions and measurement technologies that conform to the …

Prokaryotic Diversity In The Rhizosphere Of Organic, Intensive, And Transitional Coffee Farms In Brazil, Adam Caldwell, Livia Silva, Cynthia Da Silva, Cleber Ouverney

Faculty Publications, Biological Sciences

Despite a continuous rise in consumption of coffee over the past 60 years and recent studies showing positive benefits linked to human health, intensive coffee farming practices have been associated with environmental damage, risks to human health, and reductions in biodiversity. In contrast, organic farming has become an increasingly popular alternative, with both environmental and health benefits. This study aimed to characterize and determine the differences in the prokaryotic soil microbiology of three Brazilian coffee farms: one practicing intensive farming, one practicing organic farming, and one undergoing a transition from intensive to organic practices. Soil samples were collected from 20 …

Secretion Of Heat-Labile Enterotoxin By Porcine-Origin Enterotoxigenic Escherichia Coli And Relation To Virulence, Prageeth R. Wijemanne

Dissertations & Theses in Veterinary and Biomedical Science

Heat-labile enterotoxin (LT) is an important virulence factor secreted by some strains of porcine-origin enterotoxigenic Escherichia coli (pETEC). The prototypic human-origin strain H10407 secretes LT via a type II secretion system (T2SS), but its presence or importance in pETEC has not been established. Exposure of pETEC to glucose has been shown to result in different secretion levels of LT. Furthermore, the relationship between the level of LT secreted and the virulence potential of the respective pETEC strain has not been established. To determine the relationship between the capacity to secrete LT and virulence in wild-type (WT) pETEC, 16 strains isolated …

Isolation And Characterization Of Microalgae Strains For Live Food In Sulawesi, Indonesia, Wa Iba, Michael Rice

Michael A Rice

Four strains of diatoms were isolated from the waters of Kendari Bay in Southeast Sulawesi, Indonesia, including strains of Melosira moniliformis, Chaetoceros, sp. and a larger species that is likely to be Tetraselmis weissflogii. Isolated strains have exhibited a wide range of salinity tolerances in the 20 to 35 psu range. Strains of isolated phytoplankton were able to reach high densities consistent with strains suitable for use as aquaculture feeds. One strain Kbl-3 attained lipid content of 22.3 percent per gram dry weight at salinity of 35 psu, suggesting that it may be a good feed for shrimp larvae. Most …

Genomic Analyses Of Paenibacillus Polymyxa Cr1, A Bacterium With Potential Applications In Biomass Degradation And Biofuel Production, Alexander W. Eastman

Electronic Thesis and Dissertation Repository

Lignin is a polyphenolic heteropolymer constituting between 18 to 35% of lignocellulose and is recognized as preventative of cellulosic biofuel commercialization. Paenibacillus polymyxa CR1 was isolated from naturally degrading corn stover and shown to produce alcohols using lignin as a sole carbon source. Genome sequencing and comparative genomics of P. polymyxa CR1 identified two homologs, a Dyp-type peroxidase and a laccase, which have previously been implicated in lignin metabolism in other bacteria. Knockout mutants of the identified genes displayed no growth deficiency and P. polymyxa CR1 is incapable of metabolizing common aromatic intermediates of lignin, suggesting the bacterium employs a …

Cave Cyanobacteria Showing Antibacterial Activity, Vasiliki Lamprinou, Kyriaki Tryfinopoulou, Emmanuel N. Velonakis, Alkiviadis Vatopoulos, Smaragdi Antonopoulou, Elizabeth Fragopoulou, Adriani Pantazidou, Athena Economou-Amilli

International Journal of Speleology

Cave Cyanobacteria - thriving in an ‘extreme’ environment with interesting species biodiversity - are supposed to be a potential source of bioactive compounds. Lipid extracts from pure cultures of two recently established Cyanobacteria from Greek caves, Toxopsis calypsus and Phormidium melanochroun, were used for antibacterial screening against human pathogenic bacteria (reference and clinical isolates). Antimicrobial Susceptibility testing for both taxa was carried out using the disc-diffusion (Kirby Bauer) method, while preliminary data applying the standard broth microdilution method for the determination of the Minimal Inhibitory Concentration (MIC) are given only for T. calypsus. Antibacterial activity was demonstrated against the …

Comparison Of The Antibacterial, Colloidal, And Hemolytic Properties Of Novel Triple-Headed, Triscationic Amphiphiles, Tara Gallagher

Masters Theses, 2010-2019

Antibiotic resistant bacteria were first reported in the 1940s, several years after the clinical introduction of penicillin. Since then, antibiotic resistance has contributed to increasing bacterial infections, mortality rates, and treatment costs. One promising alternative to traditional antibiotics is the development and use of amphiphiles, compounds with at least one hydrophilic head group and one hydrophobic tail. Three novel series of triple-headed amphiphiles with variations in the third head group composition, tail length and number of tails (one or two) were synthesized. Isothermal titration calorimetry was used to determine the critical micelle concentration – the concentration at which amphiphiles aggregate …

Identification Of Transcription Factors Gzf3, Rfx1, Orf19.3928 As Being Implicated In Candida-Bacterial Interactions., Joni Watson

Undergraduate Honors Theses

Candida albicans is an opportunistic pathogen that is present in the normal flora in a majority of individuals. One key factor in C. albicans virulence is the ability to change its morphology from yeast to an elongated or hyphal form. The regulation of this morphogenesis relies in part upon quorum sensing (QS) molecules. C. albicans often exists as part of a mixed culture alongside other microbes and is influenced by their presence as well as the presence of QS molecules that they produce. In this study, a library of diploid homozygous transcriptional regulator knockout (TRKO) mutants were screened to identify …

Exploring The Physiological Role Of Vibrio Fischeri Pepn, Sally L. Cello

Master's Theses

The primary contributor to Vibrio fischeri aminopeptidase activity is aminopeptidase N, PepN. Colonization assays revealed the pepN mutant strain to be deficient at forming dense aggregates and populating the host’s light organ compared to wildtype within the first 12 hours of colonization; however the mutant competed normally at 24 hours. To address the role of PepN in colonization initiation and establish additional phenotypes for the pepN mutant strain, stress response and other physiological assays were employed. Marked differences were found between pepN mutant and wildtype strain in response to salinity, acidity, and antibiotic tolerance. This study has provided a foundation …