Environmental Microbiology and Microbial Ecology Commons^™

Haloferax Volcanii For Carotenoid Production, Erika Smith

Honors Theses

Carotenoids are used as natural colorants and have been shown to have numerous health benefits, making these molecules highly desirable in the aquaculture, pharmaceutical, and nutraceutical markets. There is increasing consumer demand for the natural synthesis of carotenoids, but current methods are limited by the cost and difficulty of extraction from organisms. The halophilic archaeon Haloferax volcanii is amenable to extraction and has an endogenous carotenoid biosynthetic pathway that culminates in the accumulation of the carotenoid bacterioruberin; however, H. volcanii also synthesizes important precursors that can be converted into more highly-desired carotenoids, such as β-carotene and astaxanthin, in the presence …

The Effects Of Nutrient Limitation On Toxin Production For The Harmful Algal Bloom Species, Pseudo-Nitzschia, In The Gulf Of Maine, Julia M. Park

Honors Theses

Pseudo-nitzschia is a pennate marine diatom that produces the neurotoxin domoic acid (DA). Domoic acid accumulates in the digestive tract of filter feeders and becomes concentrated at higher trophic levels. When DA concentrations reach critical levels, consumption of toxic shellfish can induce a condition known as Amnesic Shellfish Poisoning (ASP), which has been responsible for the deaths of marine mammals, seabirds and humans. This study worked to respond to a toxic Pseudo-nitzschia bloom in the Gulf of Maine during the fall of 2016, with the goal of quantifying and identifying Pseudo-nitzschia spp. in the bloom region and to determine the …

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. …

Monitoring The Influx Of Marine Derived Nitrogen And Characterizing Soil Food Webs Of Riparian Zones Of The Elwha River Watershed, Wa, Usa., Wendal R.H. Kane

EWU Masters Thesis Collection

Nitrogen is often the most limiting nutrient to productivity in terrestrial ecosystems, and can have large effects on ecosystem processes. Two sources of nitrogen to Pacific Northwest riparian areas are marine derived nitrogen (MDN) via anadromous pacific salmon and symbiotic nitrogen fixation via Alnus rubra. The recent removal of two large dams on the Elwha River, WA, opened up ~60 km of previously inaccessible river habitat for pacific salmon. I used naturally abundant stable nitrogen isotopes (denoted as ‰ δ15N) to establish baseline data to monitor the influx of MDN to riparian zones of Elwha River tributaries, post dam removal. …

Microbial Diversity In The Thermal Springs Within Hot Springs National Park, E. Taylor Stone, Richard Murray, Matthew D. Moran

Journal of the Arkansas Academy of Science

The thermal water systems of Hot Springs National Park (HSNP) in Hot Springs, Arkansas exist in relative isolation from other North American thermal systems. The HSNP waters could therefore serve as a unique center of thermophilic microbial biodiversity. However, these springs remain largely unexplored using culture-independent next generation sequencing techniques to classify species of thermophilic organisms. Additionally, HSNP has been the focus of anthropogenic development, capping and diverting the springs for use in recreational bathhouse facilities. Human modification of these springs may have impacted the structure of these bacterial communities compared to springs left in a relative natural state. The …

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 …

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.

Tracking A Tree-Killer: Improving Detection And Characterizing Species Distribution Of Phytophthora Cinnamomi In Appalachian Forests, Kenton L. Sena

Theses and Dissertations--Plant and Soil Sciences

Phytophthora cinnamomi is a soil-borne oomycete pathogen causing root rot in susceptible host species. P. cinnamomi is thought to have originated in Southeast Asia, but has since been introduced to many regions around the world, where it causes dramatic declines in many forest tree species. In the eastern US, the primary susceptible tree species of concern are American chestnut (Castanea dentata), white oak (Quercus alba), and shortleaf pine (Pinus echinata). American chestnut, functionally eliminated in the early 1900s by the rapidly acting chestnut blight (Cryphonectria parasitica), has been the subject of decades-long …

Metatranscriptome Of Human Faecal Microbial Communities In A Cohort Of Adult Men, Galeb S. Abu-Ali, Raaj S. Mehta, Jason Lloyd-Price, Himel Mallick, Tobyn Branck, Kerry L. Ivey, David A. Drew, Casey Dulong, Eric Rimm, Jacques Izard, Andrew T. Chan, Curtis Huttenhower

Department of Food Science and Technology: Faculty Publications

The gut microbiome is intimately related to human health, but it is not yet known which functional activities are driven by specific microorganisms' ecological configurations or transcription. We report a large-scale investigation of 372 human fecal metatranscriptomes and 929 metagenomes from a subset of 308 men in the Health Professionals Follow-Up Study. We identified a metatranscriptomic 'core' universally transcribed over time and across participants, often by different microorganisms. In contrast to the housekeeping functions enriched in this core, a 'variable' metatranscriptome included specialized pathways that were differentially expressed both across participants and among microorganisms. Finally, longitudinal metagenomic profiles allowed ecological …

Synthesis, Secretion, And Perception Of Abscisic Acid Regulates Stress Responses In Chlorella Sorokiniana, Maya Khasin, Rebecca E. Cahoon, Sophie Alvarez, Richard Beckeris, Seong-Il Eyun, Qidong Jia, Jean-Jack Riethoven, Kenneth Nickerson, Wayne R. Riekhof

Kenneth Nickerson Papers

Abscisic acid (ABA) is a phytohormone that has been extensively characterized in higher plants for its roles in seed and bud dormancy, leaf abscission, and stress responses. Genomic studies have identified orthologs for ABA-related genes throughout the Viridiplantae, including in unicellular algae; however, the role of ABA in algal physiology has not been characterized, and the existence of such a role has been a matter of dispute. In this study, we demonstrate that ABA is involved in regulating algal stress responses. Chlorella sorokiniana strain UTEX 1230 contains genes orthologous to those of higher plants which are essential for ABA …

Nevada Desert Dust With Heavy Metals Suppresses Igm Antibody Production, Deborah E. Keil, Brenda J. Buck, Dirk Goossens, Brett Mclaurin, Lacey Murphy, Mallory Leetham-Spencer, Yuanxin Teng, James E. Pollard, Russell Gerads, Jamie C. Dewitt

Geoscience Faculty Research

Systemic health effects from exposure to a complex natural dust containing heavy metals from the Nellis Dunes Recreation Area (NDRA) near Las Vegas, NV, were evaluated. Several toxicological parameters were examined following lung exposure to emissive dust from three geologic sediment types heavily used for recreational off-road activities: yellow sand very rich in arsenic (termed CBN 5); a shallow cover of loose dune sand overlying a gravelly subsoil bordering dune fields (termed CBN 6); and brown claystone and siltstone (termed CBN 7). Adult female B6C3F1 mice were exposed by oropharyngeal administration to these three types of geogenic dusts at 0.01–100 …

Crop Rotations That Integrate Pasture Are Less Vulnerable To Nitrogen Leaching Due To Changes In Microbial Community Composition And Reduced Nitrification, Jeth Gv Walkup

Graduate Theses, Dissertations, and Problem Reports (ETD)

Agroecosystems occupy a large portion of the United States and receive a disproportionally high amount of terrestrial nitrogen inputs. As application rates increase, nitrogen use efficiency declines leading to higher rates of nitrogen loss. To develop sustainable agricultural practices, the long-term effects of management practices on the soil microorganisms that perform central roles in the transformation of nitrogen need to be studied. To study the long-term impacts of compost application and pasture integration in crop rotation, samples were collected from the existing 19-year-old Organic Crop Livestock Field (OCLF) experiment on the WVU organic research farm. The OCLF experiment includes a …

The Influence Of Water Quality On Wetland-Associated Microbial Communities, Lindsey Clairmont

Theses and Dissertations (Comprehensive)

Within a wetland environment, bacteria in association with plant roots play a vital role in maintaining the health of freshwater ecosystems. In order to gain insight into the stability and processes occurring within natural and constructed wetland environments we need to develop a better understanding of the relationship between wetland plants, root-associated microbial communities and environmental factors. Human population growth and urbanization have resulted in greater contaminant loads (inorganic nutrients, fecal contamination etc.) entering our waterways. As such, we need a better understanding of how anthropogenic impacts influence the structure and function of the wetland-associated microbial communities that we rely …

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 …

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 …

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. …

Vibrio Vulnificus Monitoring Along The Coastal Bend And The Rio Grande Valley, Texas, Louay Bachnak

Honors Theses

Vibrio vulnificus is a common opportunistic pathogen found in marine, coastal, and estuarine waters. This one micrometer microorganism is the leading cause of deaths in the United States due to food poisoning after consumption of raw or undercooked seafood. The optimal temperature for survival is between 15.6°C and 35.0°C with moderate salinities – conditions frequently found in the Gulf of Mexico (Lin, Payne, & Schwarz, 2003).

In the United States, V. vulnificus infections are more common in states bordering the Gulf of Mexico, including Texas. However, infections can still occur in individuals consuming infected food more inland or sustain wounds …

Fungi Of Forests: Examining The Diversity Of Root-Associated Fungi And Their Responses To Acid Deposition, Donald Jay Nelsen

Graduate Theses and Dissertations

Global importance of forests is difficult to overestimate, given their role in oxygen production, ecological roles in nutrient cycling and supporting numerous living species, and economic value for industry and as recreational zones. Fitness of the forest-forming trees strongly depends on microbial communities associated with tree roots. In particular, fungi impact tree fitness: mycorrhizal species provide water and nutrients for the trees in exchange for C, endophytic fungi play key roles in host defense against pathogenic organisms, and saprotrophic fungi decompose dead organic matter and facilitate nutrient cycling. In addition, pathogenic fungal species strongly affect forest fitness. Despite their importance, …

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 …

Soil Microbiome Across A Prairie Quality Gradient: Early Assessment Of Restoration Sites, Kristen O. Anderson, Joe C. Cleys, Whitney Shegrud, Jossette Velazquez, Elias P. Holte, Sara Anderson

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Functional Characteristics And Genomic Sequencing Of Antarctic Environmental Isolates, Amanda Kemper, Christina Aigner, Michelle Tigges, Sara Anderson

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Spatial And Temporal Heterogeneity Of Microbial Life In Artificial Landscapes, Roopkamal Kaur, Aditi Sengupta, Peter A. Troch

STAR Program Research Presentations

The Landscape Evolution Observatory (LEO) project at Biosphere 2 consists of three replicated artificial landscapes which are sealed within a climate-controlled glass house. LEO is composed of basaltic soil material with low organic matter, nutrients, and microbes. The landscapes are built to resemble zero-order basins and enables researchers to observe hydrological, biological, and geochemical evolution of landscapes in a controlled environment. This study is focused on capturing microbial community dynamics in LEO soil, pre- and post-controlled rainfall episodes. Soil samples were collected from six different positions and at five depths in each of the three slopes followed by DNA extraction …

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 …

Screening Of Antifungal Susceptibility In Cave-Dwelling Aspergilli And Report Of An Amphotericin B-Resistant Aspergillus Flavus, Erika L.S. Taylor, Gabriella F. Ferreira, Gustavo J.C. Freitas, Rodrigo L. Ferreira, Daniel De Assis Santos, Maria A. De Resende-Stoianoff

International Journal of Speleology

Caves are stable environments that favour the development of several microorganisms. The aspergilli represent a large number of species isolated from caves including strains capable of causing serious invasive opportunistic infections in humans. Considering that caves may harbour resistant strains to many antibiotics, investigation on the response of opportunistic aspergilli, isolated from pristine and tourist caves to antifungal agents and the mechanisms involved in resistance might be clinically relevant. A total of 32 strains of the species Aspergillus candidus, A. flavus, A. fumigatus, A. niger, A. tamarii, and A. terreus were isolated from caves in …

Microbial Community Richness Distinguishes Shark Species Microbiomes In South Florida, Rachael Cassandra Karns

HCNSO Student Theses and Dissertations

The microbiome (microbial community) of individuals is crucial when characterizing and understanding processes that are required for organism function and survival. Microbial organisms, which make up an individual’s microbiome, can be linked to disease or function of the host organism. In humans, individuals differ substantially in their microbiome compositions in various areas of the body. The cause of much of the composition diversity is yet unexplained, however, it is speculated that habitat, diet, and early exposure to microbes could be altering the microbiomes of individuals (Human Microbiome Project Consortium, 2012b, 2012a). To date, only one study has reported on microbiome …

Bacterial Communities Associated With Healthy And Diseased Acropora Cervicornis (Staghorn Coral) Using High-Throughput Sequencing, Charles Walton

HCNSO Student Theses and Dissertations

Coral diseases were first noted in the 1960s and 1970s and have had major impacts globally on coral reef community structures. In the Caribbean, a major outbreak of white band disease has been considered responsible for the drastic decline of Caribbean Acroporids since the 1970s. In addition to white band disease, another more recently described condition known as rapid tissue loss (RTL) has had major impacts on Acropora cervicornis populations, specifically offshore Broward County Southeast Florida. While these diseases have contributed to the population decline, determining their etiologies has been elusive.

Coral diseases have been characterized by shifts in their …

How Science Makes America Great, Kenneth Nickerson

Kenneth Nickerson Papers

The proposed Federal Budget cuts funding for NIH, NSF, and CDC by 16% each and for the EPA by a whopping 31%. Ouch! The situation seems ironic because of President Trump’s slogan “Make America great again!”, which I agree with wholeheartedly. In addition to being a scientist, I also love history (especially military history) and science is at the top of my list of what has made the United States great. ... Why do we do it? I’m in science because it is rewarding. It is invigorating to discover how nature works. Scientists may act individually and in relative obscurity, …

The Role Of Dietary Highly Unsaturated N-3 Fatty Acids In Northern Quahogs, Mercenaria Mercenaria, Through Decreasing Temperature, Sixto E. Portilla

Dissertations, Theses, and Capstone Projects

The series of investigations described in this thesis were designed to assess the effect of diet on mortality through decreasing temperature in two genetic varieties of M. mercenaria important to the natural environment and the aquaculture industry: “wild” from natural stocks and “notata” selected for fast growth. Data from these novel investigations demonstrate a temperature specific sensitivity to each dietary component designating 20:5n-3 as homeoviscously favorable in the upper thermal range above 12°C, and 22:6n-3 as favorable in the lower. Statistical analyses of variance demonstrate distinct cumulative mortalities among the 5 dietary treatments (P < 0.05) for each genetic variety at each thermal range, upper (>12°C) and lower (2 = 0.9326 …

Characterization Of Zinc And Cadmium Stress Response In Cyanobacterium Synechococcus Sp. Iu 625, Robert Newby Jr

Seton Hall University Dissertations and Theses (ETDs)

The way that cyanobacteria process and interact with heavy metals is an important part of their physiology. Metals like zinc play a role in many essential cell processes; while metals such as cadmium appear to be universally toxic. Little is known about how these metals play a role in the harmful overgrowth of cyanobacteria called blooms. While individual mechanisms have been elucidated, a complete response for metals in cyanobacteria has not yet been proposed. To establish a proposed mechanism of response in cyanobacteria, work was undertaken studying the response to zinc and cadmium in Synechococcus sp. IU 625 (S. IU …

Survey Of Microbial Urea Degrader Diversity In Two Freshwater Ecosystems: Lake Shenandoah And The Shenandoah River, Naomi E. Gilbert

Senior Honors Projects, 2010-2019

One of the primary drivers of cyanobacterial harmful algal blooms (cHABs) in freshwater systems is nutrient loading, particularly of nitrogen and phosphorus. There has been an increased focus on assessing the role of nitrogen (N) in freshwater lakes and rivers that suffer cHABs. Urea, a widely-used, N-rich fertilizer, is a source of interest due to its abundance in freshwater ecosystems, primarily caused by anthropogenic nutrient loading. While recent work has shown that cHAB population succession may favor the toxic cyanobacterium Microcystis in urea-rich waters, the diversity of the associated bacterial community capable of degrading urea has yet to be determined. …