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Environmental Microbiology and Microbial Ecology Commons™

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2014

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Articles 31 - 41 of 41

Full-Text Articles in Environmental Microbiology and Microbial Ecology

Investigating The Interactions Between Cyanobacteria And Vibrio Parahaemolyticus, Caroline E. Ward Jan 2014

Investigating The Interactions Between Cyanobacteria And Vibrio Parahaemolyticus, Caroline E. Ward

Honors Theses and Capstones

One well-known pathogen that has been the topic of many recent studies is Vibrio parahaemolyticus, which causes thousands of foodborne illnesses a year, mostly from the ingestion of raw or undercooked oysters. It has been shown cyanobacteria can act as a long-term reservoir of Vibrio cholerae, another pathogenic Vibrio, by encasing the cells within mucilaginous sheaths during which Vibrios enter a viable but non-culturable state. In this study we investigated the interaction of V. parahaemolyticus with cyanobacteria to determine whether cyanobacteria aid in the longevity and survival of V. parahaemolyticus. We found that non-pathogenic V. parahaemolyticus …

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The Pleiotropic Effects Of Beneficial Mutations Of Adapted Escherichia Coli Populations, Brian Scott Van Dam Jan 2014

The Pleiotropic Effects Of Beneficial Mutations Of Adapted Escherichia Coli Populations, Brian Scott Van Dam

Honors Theses and Capstones

Mutations that improve fitness in one environment can often be beneficial, deleterious, or neutral in alternative environments. When a single mutation effects fitness in multiple environments, it is said to be a pleiotropic, which can have important consequences for niche specialization, niche expansion, speciation, and even extinction in the face of environmental change. While previous studies have revealed that pleiotropy is nearly universal, the role of adaptive history in the spectrum of pleiotropic effects has yet to undergo detailed experimental observation. Using experimental evolution we gathered beneficial mutations in a previously adapted strain of Escherichia coli growing in the same …

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The Distribution Of Fitness Effects Of Spontaneous Mutations In Vibrio Fischeri, Chelsea K. Jones Jan 2014

The Distribution Of Fitness Effects Of Spontaneous Mutations In Vibrio Fischeri, Chelsea K. Jones

Honors Theses and Capstones

Mutations are the ultimate source of the biological diversity on which natural selection acts, but the vast majority of these mutations are harmful. As such, mutations lead to disease states like cancer, extinction of small populations, and can drive pathogen evolution. Unfortunately, because mutations are rare and past studies have been subject to detection biases, very little is known about the distribution of fitness effects from naturally occurring mutations. In this study, we used mutation accumulation and full genome sequencing to capture naturally occurring mutations before they were exposed to the sieve of natural selection in Vibrio fischeri. We …

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The Role Of Surface Chemistry In The Toxicity Of Manufactured Cerium Dioxide Nanomaterials To Caenorhabditis Elegans, Emily Kay Oostveen Jan 2014

The Role Of Surface Chemistry In The Toxicity Of Manufactured Cerium Dioxide Nanomaterials To Caenorhabditis Elegans, Emily Kay Oostveen

Theses and Dissertations--Plant and Soil Sciences

Manufactured CeO2 nanomaterials (CeO2-MNMs) are used for a wide variety of applications including diesel fuel additives and chemical/mechanical planarization media. To test the effects of CeO2-MNM surface coating charge on to model organism Caenorhabditis elegans, we synthesized 4 nm CeO2 with cationic (DEAE-), anionic (CM-), and neutral (DEX) coatings. In L3 nematodes exposed for 24 hours, DEAE-CeO2 induced lethality at lower concentrations than CM- or DEX-CeO2. Feeding slightly decreased CeO2 toxicity, regardless of coating. In L2 nematodes exposed for 48 hours with feeding, DEAE-CeO2 caused lethality at the …

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A Glutathione-Independent Glyoxalase Of The Dj-1 Superfamily Plays An Important Role In Managing Metabolically Generated Methylglyoxal In Candida Albicans, Sahar Hasim, Nur Ahmad Hussin, Fadhel Alomar, Keshore R. Bidasee, Kenneth W. Nickerson, Mark A. Wilson Jan 2014

A Glutathione-Independent Glyoxalase Of The Dj-1 Superfamily Plays An Important Role In Managing Metabolically Generated Methylglyoxal In Candida Albicans, Sahar Hasim, Nur Ahmad Hussin, Fadhel Alomar, Keshore R. Bidasee, Kenneth W. Nickerson, Mark A. Wilson

Kenneth Nickerson Papers

Methylglyoxal is a cytotoxic reactive carbonyl compound produced by central metabolism. Dedicated glyoxalases convert methylglyoxal to D-lactate using multiple catalytic strategies. In this study, the DJ-1 superfamily member ORF 19.251/GLX3 from Candida albicans is shown to possess glyoxalase activity, making this the first demonstrated glutathione-independent glyoxalase in fungi. The crystal structure of Glx3p indicates that the protein is a monomer containing the catalytic triad Cys136- His137-Glu168. Purified Glx3p has an in vitro methylglyoxalase activity (Km = 5.5 mM andkcat = 7.8 s-1) that is significantly greater than that of …

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Bacteria In Bioethanol Fermentations, Qing Li Jan 2014

Bacteria In Bioethanol Fermentations, Qing Li

Theses and Dissertations--Plant and Soil Sciences

To gain a better understanding of contaminating bacteria in bioethanol industry, we profiled the bacterial community structure in corn-based bioethanol fermentations and evaluated its correlation to environmental variables. Twenty-three batches of corn-mash sample were collected from six bioethanol facilities. The V4 region of the collective bacterial 16S rRNA genes was analyzed by Illumina Miseq sequencing to investigate the bacterial community structure. Non-metric multidimensional scaling (NMDS) ordination plots were constructed to visualize bacterial community structure groupings among different samples, as well as the effects of multiple environmental variables on community structure variation. Our results suggest that bacterial community structure is facility-specific, …

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Soil Microbial Community Distributions And Disease Suppressiveness In The Coastal Plain Of Georgia, Michael J. Sabula Jan 2014

Soil Microbial Community Distributions And Disease Suppressiveness In The Coastal Plain Of Georgia, Michael J. Sabula

College of Graduate Studies: Theses & Dissertations

This study compared the soil microbial communities of three vegetation types in the coastal plain of Georgia: 1. crop land actively in use for agricultural production, 2. transitional grassland in early stages of secondary succession, and 3. pristine unmanaged forest land. Microbial species diversity and quantities of microbial DNA were determined from each of these vegetation types at three separate locations near Statesboro, Georgia. Length heterogeneity PCR(LH-PCR) methods and subsequent analysis of fungal, bacterial, and metazoan communities by analysis of similarity (ANOSIM) revealed high within-group similarity by vegetation type, indicating land management intensity and vegetation cover is a strong determining …

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Effects Of Elevated Salinity And Oxidative Stress On The Physiology Of The Toxigenic Cyanobacterium Microcystis Aeruginosa, Billy Christopher Warhurst Jan 2014

Effects Of Elevated Salinity And Oxidative Stress On The Physiology Of The Toxigenic Cyanobacterium Microcystis Aeruginosa, Billy Christopher Warhurst

UNF Graduate Theses and Dissertations

Harmful algal blooms (HABs) are found worldwide, particularly in places where warm, well-lit, and stagnant waters are common. HABs can have negative effects on aquatic plants and wildlife due to the reduction in light availability associated with turbidity, decrease in O2 availability, and the production of secondary metabolites that can harm or even prove lethal. Aquatic ecosystems are regularly being affected by elevated salinity because of recent water management strategies, episodes of drought, and salt water intrusion. This research focused on how salinity levels ranging from 0-10ppt affected physiological attributes such as cellular growth and abundance, cell mortality, toxin …

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Dielectric Barrier Discharge Atmospheric Cold Plasma For Inactivation Of Pseudomonas Aeruginosa Biofilms, Dana Ziuzina, Sonal Patil, Patrick J. Cullen, Daniela Boehm, Paula Bourke Jan 2014

Dielectric Barrier Discharge Atmospheric Cold Plasma For Inactivation Of Pseudomonas Aeruginosa Biofilms, Dana Ziuzina, Sonal Patil, Patrick J. Cullen, Daniela Boehm, Paula Bourke

Articles

In recent years, atmospheric cold plasma (ACP) has been widely investigated for potential application as an alternative decontamination technology in biomedical and healthcare sectors. In this study, the antimicrobial efficacy of ACP against Pseudomonas aeruginosa biofilms was investigated. The 48-h biofilms were treated inside sealed polypropylene containers with a high-voltage dielectric barrier discharge (DBD) ACP (80 kVRMS) and subsequently stored for 24 h at room temperature. Treatment for 60 s by either the direct or indirect mode of ACP exposure (inside or outside plasma discharge, respectively) reduced bacterial populations by an average of 5.4 log cycles from an initial 6.6 …

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Investigating The Persistence And "Naturalization" Potential Of Salmonella In Non-Host Environments Using Culture-Based And Molecular-Based Fingerprinting Techniques, Robyn L. Morrison Jan 2014

Investigating The Persistence And "Naturalization" Potential Of Salmonella In Non-Host Environments Using Culture-Based And Molecular-Based Fingerprinting Techniques, Robyn L. Morrison

Theses and Dissertations (Comprehensive)

Recent studies suggest the potential exists for enteric microorganisms to become “naturalized” to the complex natural environment through maintenance of their populations via replication and adaptation to the stress imposed by their external surroundings. The aim of this research was to better understand the potential for antimicrobial resistant (AMR) Salmonella to become “naturalized” and the physiological adaptations that allow for non-host survivability as reflected by AMR and community profiling. To better elucidate the prominent factors leading to a “naturalized” condition, two approaches were taken: 1) survey-based field research to gain perspective on the prevalence of AMR Salmonella isolated from variously …

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Identification And Ss-Lactam Resistance In Aquatic Isolates Of Enterobacter Cloacae And Their Status In Microbiota Of Domica Cave In Slovak Karst (Slovakia), Barbora Gaalova, Alena Donauerova, Milan Seman, Helena Bujdakova Jan 2014

Identification And Ss-Lactam Resistance In Aquatic Isolates Of Enterobacter Cloacae And Their Status In Microbiota Of Domica Cave In Slovak Karst (Slovakia), Barbora Gaalova, Alena Donauerova, Milan Seman, Helena Bujdakova

International Journal of Speleology

Domica Cave is located in the Slovak Karst National Park in southern Slovakia. Heterotrophic cultivable psychrophilic and mesophilic microbiota were confirmed to be prevalent in this cave. Escherichia coli was the most abundant bacterium, followed by Enterobacter species and Serrratia species. Enterobacter cloacae isolates belong to the group of faecal contaminants (coliforms) of concern in water. Their status in cave ecosystem is questionable, but we observed E. cloacae in water samples all years round suggesting an autochthonous origin. We were concerned with possible contamination of the cave water with resistant E. cloacae from animal farms located 2-3 km from the …

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