Organisms Commons^™

Complex History Of Codiversification And Host Switching Of A Newfound Soricid-Borne Orthohantavirus In North America, Schuyler W. Liphardt, Hae Ji Kang, Laurie J. Dizney, Luis A. Ruedas, Joseph A. Cook, Richard Yanagihara

Biology Faculty Publications and Presentations

Orthohantaviruses are tightly linked to the ecology and evolutionary history of their mammalian hosts. We hypothesized that in regions with dramatic climate shifts throughout the Quaternary, orthohantavirus diversity and evolution are shaped by dynamic host responses to environmental change through processes such as host isolation, host switching, and reassortment. Jemez Springs virus (JMSV), an orthohantavirus harbored by the dusky shrew (Sorex monticola) and five close relatives distributed widely in western North America, was used to test this hypothesis. Total RNAs, extracted from liver or lung tissue from 164 shrews collected from western North America during 1983–2007, were analyzed for orthohantavirus …

Fungal Endophytes In A Seed-Free Host: New Species That Demonstrate Unique Community Dynamics, Brett Steven Younginger

Dissertations and Theses

Fungal endophytes are highly diverse, cryptic plant endosymbionts that form asymptomatic infections within host tissue. They represent a large fraction of the millions of undescribed fungal taxa on our planet with some demonstrating mutualistic benefits to their hosts including herbivore and pathogen defense and abiotic stress tolerance. Other endophytes are latent saprotrophs or pathogens, awaiting host plant senescence to begin alternative stages of their life cycles. Most, however, are likely plant commensals with no observable benefits to their hosts while under study. Yet, when considering the context-dependence that may determine plant resistance to pathogen attack, the consortium of endophytes present …

Surviving Catastrophe: Resource Allocation And Plant Interactions Among The Mosses Of Mount St. Helens Volcano, Trevor David Williams

Dissertations and Theses

Mosses are some of the first colonizers to disturbed sites, yet their roles in early plant community structuring are not well understood. The primary succession zones of volcanoes provide opportunities to conduct natural experiments into how mosses contribute to early plant community formation, as well as how the unique environments found in such zones affect plant traits, particularly those associated with stress tolerance. Though plant community changes have been well-documented since Mount St. Helens (MSH) volcano erupted in 1980, the volcano's moss assemblages, their influence on other plants, and their potential roles in chemical-mediated competition and biogeochemical cycling have garnered …

Assessment Of A Mycorrhizal Fungi Application To Treat Stormwater In An Urban Bioswale, Alaina Diane Melville

Dissertations and Theses

This study assessed the effect of an application of mycorrhizal fungi to stormwater filter media on urban bioswale soil and stormwater in an infiltration-based bioswale aged 20 years with established vegetation. The study tested the use of commercially available general purpose biotic soil blend PermaMatrix^® BSP Foundation as a treatment to enhance Earthlite^™ stormwater filter media amelioration of zinc, copper, and phosphorus in an ecologically engineered structure designed to collect and infiltrate urban stormwater runoff before it entered the nearby Willamette River.

These results show that the application of PermaMatrix^® BSP Foundation biotic soil amendment to Earthlite …

Investigating The Origin And Functions Of A Novel Small Rna In Escherichia Coli, Fenil Rashmin Kacharia

Dissertations and Theses

Non-coding small RNAs (sRNAs) regulate various cellular processes in bacteria. They bind to a chaperone protein Hfq for stability and regulate gene expression by base-pairing with target mRNAs. Although the importance of sRNAs in bacteria has been well established, the mode of origination of novel sRNA genes is still elusive, mainly because the rapid rate of evolution of sRNAs obscures their original sources. To overcome this impediment, we identified a recently formed sRNA (EcsR2) in E. coli, and show that it evolved from a degraded bacteriophage gene. Our analyses also revealed that young sRNAs such as EcsR2 are expressed …

Sex-Specific Fungal Communities Of The Dioicous Moss Ceratodon Purpureus, Mehmet Ali Balkan

Dissertations and Theses

Mosses display a number of hallmark life history traits that influence their ecology at the population and community level. The long lived separation of sexes observed in the haploid gametophyte (dioicy) is one such feature of particular importance, as it is observed in the majority of bryophytes and creates intraspecific specialization of male and female individuals.

The prevalence of sexually dimorphic mosses raises the possibility of sex-specific interactions with fungi as observed in some vascular plants. Here I investigated how moss sex shapes fungal communities associated with gametophytic tissues of the ubiquitous moss, Ceratodon purpureus. Using greenhouse populations of …

Mechanisms Of Adaptation In The Newly Invasive Species Brachypodium Sylvaticum (Hudson) Beauv., Gina Lola Marchini

Dissertations and Theses

It is common knowledge that invasive species cause worldwide ecological and economic damage, and are nearly impossible to eradicate. However, upon introduction to a novel environment, alien species should be the underdogs: They are present in small numbers, possess low genetic diversity, and have not adapted to the climate and competitors present in the new habitat. So, how are alien species able to invade an environment occupied by native species that have already adapted to the local environment? To discover some answers to this apparent paradox I conducted four ecological genetic studies that utilized the invasive species Brachypodium sylvaticum (Hudson) …

Paleological And Ecological Impacts Of Virus Silicification, James Robert Laidler

Dissertations and Theses

Silicification of organisms in silica-depositing environments can impact both their ecology and their presence in the fossil record. Although microbes have been silicified under laboratory and environmental conditions, viruses had not been, prior to this work. Bacteriophage T4 was successfully silicified under laboratory conditions that closely simulated those found in silica-depositing hot springs. Virus morphology was maintained during the short period of silicification (48 hours), and a clear elemental signature of silicon and phosphorus was detected by energy-dispersive X-ray spectrophotometry (EDX). However, the EDX signature of silicified virus was not sufficiently distinct from that of cell membrane or phosphate minerals …

Community Level Impacts Associated With The Invasion Of English Ivy (Hedera Spp.) In Forest Park: A Look At The Impacts Of Ivy On Community Composition And Soil Moisture, Sara Rose Copp

Dissertations and Theses

Invasive species degrade ecosystems by altering natural processes and decreasing the abundance and diversity of native flora. Communities with major fluctuations in resource supply allow invasive species to exploit limiting resources making the community prone to invasion. In the Pacific Northwest, urban forests characterized with limited light and seasonally limited soil moisture are being dominated by nonnative English ivy (Hedera spp). Three observational studies were conducted in the Southern end of Forest Park within the Balch Creek Subwatershed in Portland, Oregon in order to understand 1) how English ivy changes over three growing seasons, 2) how the native …

Effects Of Arbuscular Mycorrhizal Fungal Infection And Common Mycelial Network Formation On Invasive Plant Competition, Rachael Elizabeth Workman

Dissertations and Theses

Understanding the biotic factors influencing invasive plant performance is essential for managing invaded land and preventing further exotic establishment and spread. I studied how competition between both conspecifics and native co-habitants and arbuscular mycorrhizal fungal (AMF) impacted the success of the invasive bunchgrass Brachypodium sylvaticumin early growth stages. I examined whether invasive plants performed and competed differently when grown in soil containing AMF from adjacent invaded and noninvaded ranges in order to determine the contribution of AMF to both monoculture stability and spread of the invasive to noninvaded territory. I also directly manipulated common mycelial network (CMN) formation by AMF …

The Boiling Springs Lake Metavirome: Charting The Viral Sequence-Space Of An Extreme Environment Microbial Ecosystem, Geoffrey Scott Diemer

Dissertations and Theses

Viruses are the most abundant organisms on Earth, yet their collective evolutionary history, biodiversity and functional capacity is not well understood. Viral metagenomics offers a potential means of establishing a more comprehensive view of virus diversity and evolution, as vast amounts of new sequence data becomes available for comparative analysis.
Metagenomic DNA from virus-sized particles (smaller than 0.2 microns in diameter) was isolated from approximately 20 liters of sediment obtained from Boiling Springs Lake (BSL) and sequenced. BSL is a large, acidic hot-spring (with a pH of 2.2, and temperatures ranging from 50°C to 96°C) located in Lassen Volcanic National …

Modeling Fecal Bacteria In Oregon Coastal Streams Using Spatially Explicit Watershed Characteristics, Paul Bryce Pettus

Dissertations and Theses

Pathogens, such as Escherichia coli and fecal coliforms, are causing the majority of water quality impairments in U.S., making up ~87% of this grouping's violations. Predicting and characterizing source, transport processes, and microbial survival rates is extremely challenging, due to the dynamic nature of each of these components. This research built upon current analytical methods that are used as exploratory tools to predict pathogen indicator counts across regional scales. Using a series of non-parametric methodologies, with spatially explicit predictors, 6657 samples from non-estuarine lotic streams were analyzed to make generalized predictions of regional water quality. 532 frequently sampled sites in …

Taxis Toward Hydrogen Gas By Methanococcus Maripaludis, Kristen A. Brileya, James M. Connolly, Carey Downey, Robin Gerlach, Matthew W. Fields

Biology Faculty Publications and Presentations

Knowledge of taxis (directed swimming) in the Archaea is currently expanding through identification of novel receptors, effectors, and proteins involved in signal transduction to the flagellar motor. Although the ability for biological cells to sense and swim toward hydrogen gas has been hypothesized for many years, this capacity has yet to be observed and demonstrated. Here we show that the average swimming velocity increases in the direction of a source of hydrogen gas for the methanogen, Methanococcus maripaludis using a capillary assay with anoxic gas-phase control and time-lapse microscopy. The results indicate that a methanogen couples motility to hydrogen concentration …

Multistate Mark-Recapture Analysis Reveals No Effect Of Blood Sampling On Survival And Recapture Of Eastern Kingbirds (Tyrannus Tyrannus), Lucas J. Redmond, Michael T. Murphy

Biology Faculty Publications and Presentations

The experimentally supported and prevailing opinion is that blood sampling has few to no long-term effects on survival of birds when conducted properly, and blood sampling has become a vital addition to the toolbox of many ornithologists. However, many of the studies that concluded that blood sampling had negligible effects on birds used approaches that did not account for temporary emigration and probability of capture. To date, the only study to have done so found that blood sampling had a strong negative effect on survival. We conducted a mark–recapture analysis of 8 years of banding and bleeding data on Eastern …

Metagenomes From High-Temperature Chemotrophic Systems Reveal Geochemical Controls On Microbial Community Structure And Function, William P. Inskeep, Douglas B. Rusch, Zackary J. Jay, Markus J. Herrgard, Mark A. Kozubal, Toby H. Richardson, Richard E. Macur, Natsuko Hamamura, Ryan Dem. Jennings, Bruce W. Fouke, Anna-Louise Reysenbach, Frank Roberto, Mark Young, Ariel Schwartz, Eric S. Boyd, Jonathan H. Badger, Eric J. Mathur, Alice C. Ortmann, Mary Bateson, Gill Geesey

Biology Faculty Publications and Presentations

The Yellowstone caldera contains the most numerous and diverse geothermal systems on Earth, yielding an extensive array of unique high-temperature environments that host a variety of deeply-rooted and understudied Archaea, Bacteria and Eukarya. The combination of extreme temperature and chemical conditions encountered in geothermal environments often results in considerably less microbial diversity than other terrestrial habitats and offers a tremendous opportunity for studying the structure and function of indigenous microbial communities and for establishing linkages between putative metabolisms and element cycling. Metagenome sequence (14-15,000 Sanger reads per site) was obtained for five hightemperature (>65°C) chemotrophic microbial communities sampled from …

The Isolation Of Viruses Infecting Archaea, Kenneth M. Stedman, Kate Porter, Mike L. Dyall-Smith

Biology Faculty Publications and Presentations

A mere 50 viruses of Archaea have been reported to date; these have been investigated mostly by adapting methods used to isolate bacteriophages to the unique growth conditions of their archaeal hosts. The most numerous are viruses of thermophilic Archaea. These viruses have been discovered by screening enrichment cultures and novel isolates from environmental samples for their ability to form halos of growth inhibition, or by using electron microscopy to screen enrichment cultures for virus-like particles. Direct isolation without enrichment has not yet been successful for viruses of extreme thermophiles. On the other hand, most viruses of extreme halophiles, the …

Rearrangement Of The Rna Polymerase Subunit H And The Lower Jaw In Archaeal Elongation Complexes, Sebastian Grünberg, Christoph Reich, Mirijam E. Zeller, Michael S. Bartlett, Michael Thomm

Biology Faculty Publications and Presentations

The lower jaws of archaeal RNA polymerase and eukaryotic RNA polymerase II include orthologous subunits H and Rpb5, respectively. The tertiary structure of H is very similar to the structure of the C-terminal domain of Rpb5, and both subunits are proximal to downstream DNA in pre-initiation complexes. Analyses of reconstituted euryarchaeal polymerase lacking subunit H revealed that H is important for open complex formation and initial transcription. Eukaryotic Rpb5 rescues activity of the ΔH enzyme indicating a strong conservation of function for this subunit from archaea to eukaryotes. Photochemical cross-linking in elongation complexes revealed a striking structural rearrangement of RNA …

Isolation Of A Ubiquitous Obligate Thermoacidophilic Archaeon From Deep-Sea Hydrothermal Vents, Anna-Louise Reysenbach, Yitai Liu, Amy B. Banta, Terry J. Beveridge, Julie D. Kirshtein, Stefan Schouten, Margaret K. Tivey, Karen L. Von Damm, Mary A. Voytek

Biology Faculty Publications and Presentations

Deep-sea hydrothermal vents are important in global biogeochemical cycles, providing biological oases at the sea floor that are supported by the thermal and chemical flux from the Earth's interior. As hot, acidic and reduced hydrothermal fluids mix with cold, alkaline and oxygenated sea water, minerals precipitate to form porous sulphide–sulphate deposits. These structures provide microhabitats for a diversity of prokaryotes that exploit the geochemical and physical gradients in this dynamic ecosystem. It has been proposed that fluid pH in the actively venting sulphide structures is generally low (pH < 4.5), yet no extreme thermoacidophile has been isolated from vent deposits. Culture-independent surveys based on ribosomal RNA genes from deep-sea hydrothermal deposits have identified a widespread euryarchaeotal lineage, DHVE2 (deep-sea hydrothermal vent euryarchaeotic 2) Despite the ubiquity and apparent deep-sea endemism of DHVE2, cultivation of this group has been unsuccessful and thus its metabolism remains a mystery. Here we report the isolation and cultivation of a member of the DHVE2 group, which is an obligate thermoacidophilic sulphur- or iron-reducing heterotroph capable of growing from pH 3.3 to 5.8 and between 55 and 75 °C. In addition, we demonstrate that this isolate constitutes up to 15% of the archaeal population, providing evidence that thermoacidophiles may be key players in the sulphur and iron cycling at deep-sea vents.

Determination Of Homology Between The Arsenic Resistance Plasmids R45 And R773 In Escherichia Coli, Joshua T. Clark

Dissertations and Theses

The resistance transfer factor R45 from Escherichia coli confers inducible arsenate and arsenite resistance in that bacterium. The genes for these resistances were cloned into the EcoR1 - Sph1 multiple cloning site of PGEM3 Blue vector (Promega) to produce a 4.9 kilobase plasmid, pJC1. This recombinant plasmid, pJC1, conferred IPTG induced resistance to arsenite and arsenate. In addition, pJCl was tested for homology with the E. coli plasmid R773, which encodes for arsenic resistance in that bacterium as well.

Through DNA-DNA hybridization the arsenic resistance determinants of R45 and R773 were compared. Under stringent hybridization conditions, R45 demonstrated DNA sequence …

The Absence Of Extrachromosomal Dna In Methanogenic Bacteria, Nancy Ann Kurkinen

Dissertations and Theses

Five species of methanogenic bacteria were analyzed for the presence of plasmid DNA. Several procedures for the detection and isolation of covalently closed circular plasmid DNA were modified for use with the methanogens.