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Articles 121 - 150 of 226

Full-Text Articles in Environmental Microbiology and Microbial Ecology

High-Throughput Cultivation Of Bacterioplankton From The Gulf Of Mexico And Genomics Of The First Cultured Ld12 Representative, Michael Winslow Henson Jan 2019

High-Throughput Cultivation Of Bacterioplankton From The Gulf Of Mexico And Genomics Of The First Cultured Ld12 Representative, Michael Winslow Henson

LSU Doctoral Dissertations

Cultivation of microorganisms facilitates characterization of metabolism, interspecies dependencies, virus-host interactions, and other information necessary to resolve the functions and distribution of individual taxa. However, the metabolic and physiological capacities for the majority of microbes remains unresolved because of the lack of cultivated representatives for many groups limits our ability to test cultivation-independent observations. The Northern Gulf of Mexico offers a diversity of ecosystems under the continuous threat from natural and anthropogenic disturbances, yet little is known about its native bacterioplankton community. This dissertation sought to use high-throughput cultivation over three-years at six sites to isolate important coastal bacteria to …

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Assessing The Prevalence Of Multidrug Resistant Salmonella Enterica From Stream Sediment And Poultry Litter In The Shenandoah Valley Of Virginia, Noah Greenman Jan 2019

Assessing The Prevalence Of Multidrug Resistant Salmonella Enterica From Stream Sediment And Poultry Litter In The Shenandoah Valley Of Virginia, Noah Greenman

Masters Theses, 2010-2019

Multidrug resistant Salmonella enterica present in stream sediment and poultry litter represent a critical health concern. A small number of S. enterica serotypes are responsible for most lab-confirmed infections in the US each year. To assess the prevalence of these significant strains, we isolated 88 S. enterica from stream sediment and poultry litter. Sequence data for all isolates were generated using an Illumina® sequencing platform, with long-reads for some isolates from the Oxford Nanopore MinION™ used in a hybrid genome assembly approach. Isolates were typed according to their serotype and multi-locus sequence type using SeqSero/SISTR and Enterobase respectively. Antibiotic resistance …

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Impact Of Industrial Biocides On Bacterial Isolates From Hydraulic Fracturing Produced Water, Waad Ahmed Aljohani Jan 2019

Impact Of Industrial Biocides On Bacterial Isolates From Hydraulic Fracturing Produced Water, Waad Ahmed Aljohani

Dissertations, Master's Theses and Master's Reports

Biocides are antimicrobial compounds that are designed to kill diverse groups of microbes in an untargeted fashion. Glutaraldehyde and DBNPA are commonly used to manage microbial growth in different industries. It is possible that biocide use may result in the development of bacterial resistance. However, resistance to DBNPA is believed to be limited under normal use conditions. We isolated a number of bacteria from produced water from a hydraulically fractured site in West Texas. We then tested the ability of these isolates to resist Glutaraldehyde and DBNPA. In this study, we found that these isolates have varying resistance to these …

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Preconditioning Of The Tumor Microenvironment By Means Of Low Dose Chemotherapies For An Effective Immunotherapy Of Breast Cancer, Hussein F. Aqbi Jan 2019

Preconditioning Of The Tumor Microenvironment By Means Of Low Dose Chemotherapies For An Effective Immunotherapy Of Breast Cancer, Hussein F. Aqbi

Theses and Dissertations

Breast cancer mortality is mainly due to distant recurrence of the disease arising from dormant tumor cells established by cancer therapies. Patients who initially respond to cancer therapies often succumb to distant recurrence of the disease. It is not clear why people with the same type of breast cancer respond to treatments differently; some escape from dormancy and relapse earlier than others. In addition, some tumor clones respond to immunotherapy while others do not. We investigated how autophagy plays a role in accelerating or delaying recurrence of neu overexpressing mouse mammary carcinoma (MMC) following adriamycin (ADR) treatment, and in affecting …

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Context Is Everything: An Investigation Of Spanish River Carbonatite And Its Effects On Soil-Plant-Microorganism Systems, James Mc Jones Jan 2019

Context Is Everything: An Investigation Of Spanish River Carbonatite And Its Effects On Soil-Plant-Microorganism Systems, James Mc Jones

Theses and Dissertations (Comprehensive)

With growing concerns about agricultural sustainability and food security, the use of rock fertilizers and agrominerals is receiving renewed interest. A wide variety of geological resources have been proposed as crop nutrient sources, with silicate rocks the predominant focus. Carbonatite rocks are known to weather more readily than silicate rocks; yet, they have received relatively little attention as it is thought their high Ca and Mg contents hinder effective nutrient release. However, there is strong evidence that the nutrients within carbonatite rocks are easily accessible to plants, and that these rocks have noticable effects on crop plant growth. Here I …

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Phenotypic And Transcriptomic Characterization Of Colonial Phase Variation In The Cholera Pathogen Reveals A Novel Smooth Biofilm-Defective Form, Bliss Nicole Lambert Dec 2018

Phenotypic And Transcriptomic Characterization Of Colonial Phase Variation In The Cholera Pathogen Reveals A Novel Smooth Biofilm-Defective Form, Bliss Nicole Lambert

LSU Doctoral Dissertations

Biofilm formation, through the production of Vibrio polysaccharide (VPS), greatly enhances the environmental fitness and pathogenic success of Vibrio cholerae. As a result of phase variation, V. cholerae can switch from a smooth form to rugose, whose cells produce excess VPS, resulting in highly structured biofilms and greater resistance to stress. To further characterize the reversible process of phase variation, we isolated three colonial lineages. Each lineage began with a smooth parent, N16961, and contained a rugose variant derived from the parent, N16961R, as well as a smooth revertant of the rugose, N16961SD. We found clear phenotypic and transcriptomic …

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Methanogens, Plausible Extraterrestrial Life Forms On Mars, And Their Tolerance To Increasing Concentrations Of Illite Clay, Chandler Kern Dec 2018

Methanogens, Plausible Extraterrestrial Life Forms On Mars, And Their Tolerance To Increasing Concentrations Of Illite Clay, Chandler Kern

Biological Sciences Undergraduate Honors Theses

Methanogens, some of Earth’s most primitive prokaryotic organisms, are candidates for possible life forms capable of inhabiting Mars. Specifically, four different species (Methanobacterium formicicum, Methanococcus maripaludis, Methanosarcina barkeri, Methanothermobacter wolfeii) were analyzed for their tolerance to the presence of illite clay. Illite is a crystalline mineral that has been identified from regions of Mars’s surface. Results indicated that all four species grew with some success in the illite at different concentrations. This experimentation with methanogens’ abilities to survive and reproduce in the presence of illite allows for a more accurate understanding of the potential capability of microbial …

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High-Resolution Identification Of Multiple Salmonella Serovars In A Single Sample By Using Crispr-Seroseq, Cameron P. Thompson, Alexandra N. Doak, Naufa Amirani, Erin A. Schroeder, Justin Wright, Subhashinie Kariyawasam, Regina Lamendella, Nikki Shariat Oct 2018

High-Resolution Identification Of Multiple Salmonella Serovars In A Single Sample By Using Crispr-Seroseq, Cameron P. Thompson, Alexandra N. Doak, Naufa Amirani, Erin A. Schroeder, Justin Wright, Subhashinie Kariyawasam, Regina Lamendella, Nikki Shariat

Biology Faculty Publications

Salmonella enterica is represented by >2,600 serovars that can differ in routes of transmission, host colonization, and in resistance to antimicrobials. S. enterica is the leading bacterial cause of foodborne illness in the United States, with well-established detection methodology. Current surveillance protocols rely on the characterization of a few colonies to represent an entire sample; thus, minority serovars remain undetected. Salmonella contains two CRISPR loci, CRISPR1 and CRISPR2, and the spacer contents of these can be considered serovar specific. We exploited this property to develop an amplicon-based and multiplexed sequencing approach, CRISPR-SeroSeq (serotyping by sequencing of the CRISPR loci), to …

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Microbial Ecology Of South Florida Surface Waters: Examining The Potential For Anthropogenic Influences, Chase P. Donnelly Aug 2018

Microbial Ecology Of South Florida Surface Waters: Examining The Potential For Anthropogenic Influences, Chase P. Donnelly

HCNSO Student Theses and Dissertations

South Florida contains one of the largest subtropical wetlands in the world, and yet not much is known about the microbes that live in these surface waters. These microbes play an important role in chemical cycling and maintaining good water quality for both human and ecosystem health. The hydrology of Florida’s surface waters is tightly regulated with the use of canal and levee systems run by the US Army Corps of Engineers and The South Florida Water Management District. These canals run through the Everglades, agriculture, and urban environments to control water levels in Lake Okeechobee, the Water Conservation Areas, …

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Green Tea Polyphenol Epigallocatechin-3-Gallate-Stearate Inhibits The Growth Of Streptococcus Mutans: A Promising New Approach In Caries Prevention, Amy Lynn Melok, Lee Lee, Siti Ayuni Mohamed Yussof, Tinchun Chu Aug 2018

Green Tea Polyphenol Epigallocatechin-3-Gallate-Stearate Inhibits The Growth Of Streptococcus Mutans: A Promising New Approach In Caries Prevention, Amy Lynn Melok, Lee Lee, Siti Ayuni Mohamed Yussof, Tinchun Chu

Department of Biology Faculty Scholarship and Creative Works

Streptococcus mutans (S. mutans) is the main etiological bacteria present in the oral cavity that leads to dental caries. All of the S. mutans in the oral cavity form biofilms that adhere to the surfaces of teeth. Dental caries are infections facilitated by the development of biofilm. An esterified derivative of epigallocatechin-3-gallate (EGCG), epigallocatechin-3-gallate-stearate (EGCG-S), was used in this study to assess its ability to inhibit the growth and biofilm formation of S. mutans. The effect of EGCG-S on bacterial growth was evaluated with colony forming units (CFU) and log reduction; biofilm formation was qualitatively determined by Congo red assay, …

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Differential Preservation Of Endogenous Human And Microbial Dna In Dental Calculus And Dentin, Allison E. Mann, Susanna Sabin, Kirsten Ziesemer, Ashild J. Vagene, Hannes Schroeder, Andrew T. Ozga, Krithivasan Sankaranarayanan, Courtney A. Hofman, James A. Fellows Yates, Domingo C. Salazar-Garcia, Bruno Frohlich, Mark Aldenderfer, Menno Hoogland, Christopher Read, George R. Milner, Anne C. Stone, Cecil M. Lewis Jr., Johannes Krause, Corinne Hofman, Kirsten I. Bos, Christina Warinner Jun 2018

Differential Preservation Of Endogenous Human And Microbial Dna In Dental Calculus And Dentin, Allison E. Mann, Susanna Sabin, Kirsten Ziesemer, Ashild J. Vagene, Hannes Schroeder, Andrew T. Ozga, Krithivasan Sankaranarayanan, Courtney A. Hofman, James A. Fellows Yates, Domingo C. Salazar-Garcia, Bruno Frohlich, Mark Aldenderfer, Menno Hoogland, Christopher Read, George R. Milner, Anne C. Stone, Cecil M. Lewis Jr., Johannes Krause, Corinne Hofman, Kirsten I. Bos, Christina Warinner

Biology Faculty Articles

Dental calculus (calcified dental plaque) is prevalent in archaeological skeletal collections and is a rich source of oral microbiome and host-derived ancient biomolecules. Recently, it has been proposed that dental calculus may provide a more robust environment for DNA preservation than other skeletal remains, but this has not been systematically tested. In this study, shotgun-sequenced data from paired dental calculus and dentin samples from 48 globally distributed individuals are compared using a metagenomic approach. Overall, we find DNA from dental calculus is consistently more abundant and less contaminated than DNA from dentin. The majority of DNA in dental calculus is …

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Changes In The Microbial Community Of Lubomirskia Baicalensis Affected By Red Sponge Disease, Colin Rorex May 2018

Changes In The Microbial Community Of Lubomirskia Baicalensis Affected By Red Sponge Disease, Colin Rorex

Electronic Theses and Dissertations

Lake Baikal is the oldest known lake and a unique ecosystem, home to several species of fresh water sponge. A disease outbreak affecting the dominant species, Lubormirskia baialensis, was recently reported. The cause of the disease has not been determined but one of the current hypothesis is that the increase in methane concentration is correlated to the disease outbreak. This pilot study characterized the microbiomes of sick and healthy sponges through the use of 16S rRNA sequencing. Sick sponge microbiomes shared a conserved group of taxa while the healthy sponge microbiomes had greater diversity. Indicator species analysis identified two significant …

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The Role And Contribution Of Saprotrophic Fungi During Standing Litter Decomposition Of Two Perennial Grass Species, Schizachyrium Scoparium And Schizachyrium Tenerum, Matthew Lodato May 2018

The Role And Contribution Of Saprotrophic Fungi During Standing Litter Decomposition Of Two Perennial Grass Species, Schizachyrium Scoparium And Schizachyrium Tenerum, Matthew Lodato

Master's Theses

In terrestrial ecosystems, most of the plant biomass produced enters the detrital pool, where microbial decomposers colonize, enzymatically degrade, and assimilate plant litter carbon and nutrients in amounts sufficient to bring about the decomposition of plant litter. Here, I estimated the biomass and production of fungi and microbial respiration associated with decaying Schizachyrium scoparium and Schizachyrium tenerum leaf litter, and constructed a partial organic matter budget estimating C flow into and through fungal decomposers. Significant losses in S. scoparium (57%) and S. tenerum (68%) leaf mass was observed during litter decomposition along with concomitant increases in fungal biomass, which reached …

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Predator-By-Environment Interactions Mediate Bacterial Competition In The Dictyostelium Discoideum Microbiome, R Fredrik Inglis, Odion Asikhia, Erica Ryu, David C. Queller, Joan E. Strassmann Apr 2018

Predator-By-Environment Interactions Mediate Bacterial Competition In The Dictyostelium Discoideum Microbiome, R Fredrik Inglis, Odion Asikhia, Erica Ryu, David C. Queller, Joan E. Strassmann

Biology Faculty Research

Interactions between species and their environment play a key role in the evolution of diverse communities, and numerous studies have emphasized that interactions among microbes and among trophic levels play an important role in maintaining microbial diversity and ecosystem functioning. In this study, we investigate how two of these types of interactions, public goods cooperation through the production of iron scavenging siderophores and predation by the social amoeba Dictyostelium discoideum, mediate competition between two strains of Pseudomonas fluorescens that were co-isolated from D. discoideum. We find that although we are able to generally predict the competitive outcomes between …

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Abundance Of Methanosaeta Concilii-Like Species In The Sediment Of Ledbetter Creek Embayment Of Kentucky Lake, Juanita Von Dwingelo Jan 2018

Abundance Of Methanosaeta Concilii-Like Species In The Sediment Of Ledbetter Creek Embayment Of Kentucky Lake, Juanita Von Dwingelo

Murray State Theses and Dissertations

Reservoirs, including Kentucky Lake, are unique in that they do not follow a natural cycle of rising during the rainy seasons and dropping during the dry summers. The lake is manipulated, mainly for flood control and transportation, so that the water level is increased during the summer months and decreased during the winter months. This manipulation leaves the littoral sediment of the lake submerged in the summer and exposed in the winter. The seasonal water level, along with other factors, like farming practices in the watershed, contributes to the availability of nutrients for organisms inhabiting the sediment of the lake. …

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Impacts Of Trace Metal Pollution, Urbanization And Aquifer Recharge On Spokane River Macroinvertebrates, Carolyn K. Connelly Jan 2018

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. …

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Microbial Community Response To Light And Heavy Crude Oil In Freshwater Systems, Timothy M. Butler Jan 2018

Microbial Community Response To Light And Heavy Crude Oil In Freshwater Systems, Timothy M. Butler

Dissertations, Master's Theses and Master's Reports

With increased demand for oil, there is an increased risk for oil spills in many environments. A number of pipelines transport oil near or across freshwater systems including the Great Lakes. Microbes are capable of breaking down oil and have thus been proposed as tools for oil spill response through bioremediation. There is a need to understand the microbial response to diverse oil types in freshwater environments due to the lack of research into this topic. This study’s main objectives are to understand how the freshwater microbial communities respond to oil, and how the bacterial communities may respond to different …

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Photosynthetic Activity Under Low Light, Danijela Lonco Jan 2018

Photosynthetic Activity Under Low Light, Danijela Lonco

Williams Honors College, Honors Research Projects

Are bacteria capable of undergoing oxygenic photosynthesis under low-light conditions inside of caves? Inside of an Australian cave, Chlorophyll f was recently discovered. This chlorophyll pigment was found to demonstrate the capability for photosynthesis, suggesting that Chlorophyll f extends the spectrum of usable light needed for oxygenic photosynthesis (Lars, 2015). Due to the findings in this study, a team went to Carlsbad Caverns to see if there were any bacteria capable of undergoing oxygenic photosynthesis under low light.

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Relationships Between Factors Influencing Biofilm Formation And Pathogen Retention In Complex Rhizosphere Microbial Communities, Aaron Coristine Jan 2018

Relationships Between Factors Influencing Biofilm Formation And Pathogen Retention In Complex Rhizosphere Microbial Communities, Aaron Coristine

Theses and Dissertations (Comprehensive)

Riparian wetlands are unique habitats facilitating all forms of life. The riverbanks of these environments provide ideal conditions for bacteria, plants, and higher organisms. Of particular interest to this research was the variation in microbial community structure at high, intermediate and poor water quality impacted areas. Assessing the capabilities of plants to retain microbial pathogens was identified. Root systems and corresponding soil are ideal locations for bacterial deposition, resulting in attachment at these areas. Biofilm production in these regions is important for long-term establishment, leading to persistence and potential naturalization. Opportunistic pathogens originating from mammalian fecal matter are introduced into …

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Molecular And Evolutionary Analysis Of Cyanobacterial Taxonomic Methods, Chelsea Denise Villanueva Jan 2018

Molecular And Evolutionary Analysis Of Cyanobacterial Taxonomic Methods, Chelsea Denise Villanueva

UNF Graduate Theses and Dissertations

Cyanobacteria are a group of photo-oxygenic bacteria found in nearly every ecosystem, but much cyanobacterial diversity, in various habitats, has yet to be explored. Cyanobacteria are often conspicuous components of photosynthetic flora, providing significant carbon and nitrogen inputs to surrounding systems. As possible primary colonizers of stone substrates not native to this region, cyanobacteria isolated from headstones may provide biogeographically informative data. An exploratory study of lichen-dominated microbial consortia, growing on headstones, was conducted to isolate and identify novel microaerophytic cyanobacteria, and resulted in the establishment of four novel cyanobacterial taxa. Phylogenetic analyses of photobionts in one tripartite lichen revealed …

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Anaerobic Oxidation Of Ethane, Propane, And Butane By Marine Microbes: A Mini Review, Rajesh Singh, Michael S. Guzman, Arpita Bose Oct 2017

Anaerobic Oxidation Of Ethane, Propane, And Butane By Marine Microbes: A Mini Review, Rajesh Singh, Michael S. Guzman, Arpita Bose

Biology Faculty Research

The deep ocean and its sediments are a continuous source of non-methane short-chain alkanes (SCAs) including ethane, propane, and butane. Their high global warming potential, and contribution to local carbon and sulfur budgets has drawn significant scientific attention. Importantly, microbes can use gaseous alkanes and oxidize them to CO2, thus acting as effective biofilters. A relative decrease of these gases with a concomitant 13C enrichment of propane and n-butane in interstitial waters vs. the source suggests microbial anaerobic oxidation. The reported uncoupling of sulfate-reduction (SR) from anaerobic methane oxidation supports their microbial consumption. To date, strain …

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Bacterial Diversity Impacts As A Result Of Combined Sewer Overflow In A Polluted Waterway, Olga Calderón, Holly Porter-Morgan, Joby Jacob, Willis Elkins Sep 2017

Bacterial Diversity Impacts As A Result Of Combined Sewer Overflow In A Polluted Waterway, Olga Calderón, Holly Porter-Morgan, Joby Jacob, Willis Elkins

Publications and Research

Newtown Creek is an industrial waterway and former tidal wetland in New York City. It is one of the most polluted water bodies in the United States and was designated as a superfund site in 2010. For over a century, organic compounds, heavy metals, and other forms of industrial pollution have disrupted the creek’s environment. The creek is also impacted by discharges from twenty combined sewer overflow pipes, which may deposit raw sewage or partially treated wastewater directly into the creek during heavy or sustained rain events. Combined sewer overflow events and associated nutrient over-enrichment at the creek drive eutrophication …

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Ancient Bacteria–Amoeba Relationships And Pathogenic Animal Bacteria, Joan E. Strassmann, Longfei Shu May 2017

Ancient Bacteria–Amoeba Relationships And Pathogenic Animal Bacteria, Joan E. Strassmann, Longfei Shu

Biology Faculty Research

Long before bacteria infected humans, they infected amoebas, which remain a potentially important reservoir for human disease. Diverse soil amoebas including Dictyostelium and Acanthamoeba can host intracellular bacteria. Though the internal environment of free-living amoebas is similar in many ways to that of mammalian macrophages, they differ in a number of important ways, including temperature. A new study in PLOS Biology by Taylor-Mulneix et al. demonstrates that Bordetella bronchiseptica has two different gene suites that are activated depending on whether the bacterium finds itself in a hot mammalian or cool amoeba host environment. This study specifically shows that B. …

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Range-Wide Prevalence And Impacts Of Pseudocercosporella Inconspicua On Lilium Grayi And An Assessment Of L. Superbum And L. Michauxii As Reservoirs, Cindy L. Barrett May 2017

Range-Wide Prevalence And Impacts Of Pseudocercosporella Inconspicua On Lilium Grayi And An Assessment Of L. Superbum And L. Michauxii As Reservoirs, Cindy L. Barrett

Electronic Theses and Dissertations

Lilium grayi (Gray’s Lily), a southern Appalachian endemic species, is threatened by a Lilium-specific fungal pathogen, Pseudocercosporella inconspicua. The disease is characterized by tan lesions that can cause early senescence, while also lowering seed production and viability. This project tested for P. inconspicua conidia and accessed health at nine locations. The disease was present and ubiquitous across the range of L. grayi. Through identification of P. inconspicua conidia in the field, L. superbum (Turk’s Cap Lily) was identified as an additional host, while L. michauxii (Michaux’s Lily) was disease-free. However, infection was inducible in both species. With …

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Microflora In The Cheek Pouches Of Ord's Kangaroo Rat (Dipodomys Ordii) From The Nebraska Sandhills, Devin M. Christensen Mar 2017

Microflora In The Cheek Pouches Of Ord's Kangaroo Rat (Dipodomys Ordii) From The Nebraska Sandhills, Devin M. Christensen

UNO Student Research and Creative Activity Fair

The microflora living within the Ord’s kangaroo rat (Dipodymis ordii) cheek pouches has never been extensively studied before. Kangaroo rats use their cheek pouches to transport seeds and grasses in their mouths that they later store. It is predicted that the cheek pouches harbor fungal and bacterial growth that could be either helpful or harmful to the kangaroo rat and its environment. 8 kangaroo rats were humanely captured using Sherman live traps in the Nebraska Sandhills; their cheek pouches were swabbed, and the microorganisms obtained were grown on agar plates and in liquid media until an adequate amount …

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Media Optimization, Scale-Up And Repeated Fed-Batch Operations For The Production Of 1,3-Propanediol From Glycerol By Halanaerobium Hydrogeniformans, Shivani Kalia Jan 2017

Media Optimization, Scale-Up And Repeated Fed-Batch Operations For The Production Of 1,3-Propanediol From Glycerol By Halanaerobium Hydrogeniformans, Shivani Kalia

Masters Theses

"The development of renewable energy sources, such as biofuels, is of great interest in today's world due to depletion of fossil fuels and concerns about climate change. The production of the main by-product, crude glycerol, in biodiesel production presents an opportunity for the production of industrially relevant commodities. Crude glycerol in biodiesel waste is highly impure and possesses high salt concentrations and alkalinity, making it infeasible for direct industrial utilization. Moreover, current glycerol purification methods are highly cost-intensive, necessitating a search for cost-effective approaches that are feasible to employ. Genome data analysis of Halanaerobium hydrogeniformans, revealed the metabolic capability …

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Molecular Diversity Of Foliar Fungal Endophytes In Relation To Defense Strategies And Disease In Whitebark Pine, Lorinda Bullington Jan 2017

Molecular Diversity Of Foliar Fungal Endophytes In Relation To Defense Strategies And Disease In Whitebark Pine, Lorinda Bullington

Graduate Student Theses, Dissertations, & Professional Papers

An invasive fungal pathogen, Cronartium ribicola (the causative agent of white pine blister rust) infects and kills whitebark pine (Pinus albicaulis) throughout the western US. Blister rust has decreased whitebark pine populations by over 90% in some areas. Whitebark pine, a keystone species, has been proposed for listing under the Endangered Species Act in the U.S., and the loss of this conifer is predicted to have severe impacts on forest composition and function in high elevations. Hundreds of asymptomatic fungal species live inside whitebark pine tissue, and recent studies suggest that these fungi can influence the frequency and …

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Fecal Bacterial Communities As An Indicator Of Trophic Interactions Among Anuran Larvae, Steven Jacob Everman Dec 2016

Fecal Bacterial Communities As An Indicator Of Trophic Interactions Among Anuran Larvae, Steven Jacob Everman

Master's Theses

Anurans are mass spawners, often with multiple females spawning together, resulting in thousands of tadpoles sharing a habitat. Such large numbers of tadpoles with limited dispersal can lead to intense competition for resources. Inter and intra-specific competition for food could have negative impacts on the growth and survival of smaller tadpoles. Fecal bacterial communities have the potential to be used as indicators of changes in diet making it possible to determine if tadpoles in the wild are eating the same food or not. After feeding on two prepared diets that differed in the percentage of complex carbohydrates, the fecal bacterial …

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Plant-Biocrust Interactions Mediated By The Fungal Loop, Eva Dettweiler-Robinson Nov 2016

Plant-Biocrust Interactions Mediated By The Fungal Loop, Eva Dettweiler-Robinson

Biology ETDs

Plant-microbial interactions influence biogeochemical cycles. Plants and biological soil crusts are primary producers in drylands. Biocrusts include cyanobacteria, lichens, mosses, algae, fungi, bacteria, and archaea on the soil surface, some of which fix atmospheric nitrogen. I investigated controls on biocrust carbon fluxes and their contribution to ecosystem fluxes, the incorporation of plant-derived carbon into biocrusts, and the role of soil fungi in promoting performance of plants and biocrusts. Biocrusts responded to temperature and moisture differently by biome. Biocrusts in grasslands/shrublands contributed >25% of total summertime ecosystem respiration, but biocrusts in savannas/woodlands contributed < 1%. Biocrusts contributed < 2% to GPP in any biome. To augment their native photosynthesis, biocrusts may include 16% plant-derived carbon. Fungal connections improved plant and biocrust performance and reduced differences in the CN ratio between organisms compared to when connections were impeded. Investigation of interactions among biocrusts, plants, and fungi has improved understanding of resource cycling in drylands.

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Do Novel Weapons That Degrade Mycorrhizal Mutualisms Explain Invasive Species Success?, Philip L. Pinzone Mr. Aug 2016

Do Novel Weapons That Degrade Mycorrhizal Mutualisms Explain Invasive Species Success?, Philip L. Pinzone Mr.

Biology Theses

Invasive plants often dominate novel habitats where they did not co-evolve with local species. Several hypotheses suggest mechanisms that explain increased exotic plant success, including 'novel weapons' and 'degraded mutualisms'. Japanese knotweed (Fallopia japonica) and European buckthorn (Rhamnus cathartica) are widespread plant invaders in North America that can dominate ecosystems. The goal of this study is to test whether these impacts are more consistent with novel weapons or degraded mutualism hypotheses. I examine tree seedling recruitment, (germination and initial survival) growth, (biomass) and mycorrhizal invasion (AMF content) as a function of F. japonica and R. cathartica …

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