Pactamycin, a complex aminocyclitol compound produced by Streptomyces pactum, has significant antibiotic, antitumor, and antiplasmodial activity. However, this natural product has not been developed for clinical use due to its high cytotoxicity. Modulation of its biological properties by chemical synthesis has been difficult due to its complex chemical structure. Therefore,...
Full Text:
By
Andrew Osborn
An Undergraduate Thesis Submitted to
Oregon State University
Many of the tangible benefits of catch share programs (e.g., reducing overcapacity) are dependent on the trading of shares. Additional trading-related questions (such as whether landings will change port or be concentrated geographically) are also important to the overall evaluation of a fishery, but are often asked only during post-implementation...
Fishers (Pekania pennanti) are medium sized mustelids endemic to North America. Two fisher populations persist in Oregon: an indigenous population in southwestern Oregon, and a reintroduced population in the southern Cascade Mountains. Despite candidacy for listing under the Endangered Species Act, current information on fisher populations in Oregon is scarce....
Since the mid-1960s fish production has become increasingly market-driven with actors downstream in the commodity chain increasingly determining the price of fish. Previously, it has been shown that fishers' incomes tend to be low in both developed and developing countries and that linking fisheries to global markets causes income inequalities....
Streams and rivers play a critical role in global carbon (C) cycling by processing, storing, and transporting C. Headwater streams which make up more than 95% of the length of streams and rivers worldwide have disproportionate influence on fluvial C dynamics. The hyporheic zone (HZ) of headwater streams is a...
Corals provide a diversity of ecosystem services, are among the most biologically diverse ecosystems on Earth, and directly support ~500 million people globally; however, corals are increasingly experiencing significant threats and are undergoing severe bleaching events as the result of the warming climate. Using a two-year data set surrounding a...
A growing body of literature exists on how human population growth and changes in climatic factors influence the availability of water (Elliot et al. 2014, Prudhomme et al. 2014). These studies typically conclude that climate change is expected to have negative consequences on water availability, an effect that is magnified...
Oregon's land use planning system is often recognized as having been successful in its goals of limiting urban sprawl and protecting resource lands from development. However, it is difficult to quantify the impact of these regulations, because we cannot observe what would have happened in the absence of land use...
Two striking characteristics of human beings are the diversity of resources that we use to sustain our lives and the extent to which we engage in coordinated, collective efforts to obtain and consume these resources. Together, these two characteristics are the foundation of human subsistence patterns. In many remote Alaskan...
This study explores the context of and impacts resulting from a broad range of university student civic engagements on the city of Corvallis, Oregon. Through semi-structured interviews with local community partners who engage with the university in what I term student civic service-learning, feedback reveals impacts that are overwhelmingly positive,...
Wheat (Triticum aestivum) is one of the world’s major staple food crops, with flour produced from starchy endosperm being used for breads, cakes, noodles and various other wheat-based foods. The unique bread making properties of wheat are primarily attributed to its gluten-forming storage proteins: gliadins and glutenins. This study investigated...
Native America tribes and community members throughout Oregon have asserted a strong opposition to the fossil fuel industry’s attempt to expand railways, build pipelines, and construct refineries, holding facilities, and export terminals. Despite the limited presence of fossil fuel infrastructure in the state, however, the industry is actively pursuing permits...
Evaporation synergy is the phenomenon in which two porous medium textures that share a common vertical boundary experience a higher cumulative evaporation than either homogeneous texture can produce. Studies that have been conducted to date address this phenomenon in relatively fine and coarse sands but not in finer textured soils...
This thesis explores the reasons for conversion to Islam for ten well-educated, Caucasian, American born women of European descent in a small, relatively affluent college town in Oregon, United States. It follows their process of constructing a new identity with their families, with friends, within the Muslim community and within...
A study is conducted to provide information useful to the future development of agro-pastoralists
in the Kolda Region through an economic and socio-cultural analysis of the
practice of stabling. Two main issues are addressed: the generation and distribution of
profits and the factors related to adoption of stabling. A partial...
To increase the knowledge needed to successfully implement the ecosystem-based approach to fishery management, this dissertation investigates important issues within the economics of choice and the economics of displacement. In particular, a discrete choice model of the fishing location decision in the Newport, Oregon bottom trawl groundfish fishery is estimated...
A biological inventory of the butterflies of the H. J. Andrews Experimental Forest [HJA] in Linn/Lane County, Oregon was conducted during 1994 and 1995. It was the first comprehensive survey of HJA butterflies for the site and serves as a baseline for future butterfly research. A detailed ecological account is...
Vessel disasters (e.g., vessels capsizing, sinking, grounding, burning) are the leading contributor to occupational fatalities in the U.S. commercial fishing industry. Vessel disasters are a vital area to target prevention efforts, yet it has been suggested that results produced in scientific studies are not efficiently exchanged between researchers, regulatory bodies...
The effect of anthropogenic disturbance on river systems is gaining attention, and concerns about the state of freshwater natural resources are increasing globally, as are efforts to restore habitat that has been degraded by disturbance. In rivers, non-point source pollution affects the physical characteristics of the habitat and the endemic...
Ectomycorrhizal fungi (EmF) form symbioses with trees. These symbioses profoundly influence forest ecology. Certain EmF form specialized profusions of hyphae, known as ectomycorrhizal fungal mats (mats) which are visible to the naked eye, alter forest soil biogeochemistry, substantially contribute to soil microbial biomass/respiration and support unique microbial communities. Piloderma and...
A simple debris-slide model, employing a digital elevation model (DEM) and geological data, was used in a geographic information system (GIS) to map slope stability in the Andrews Experimental Forest, located in the western Cascade Range in Oregon, USA. To evaluate the contribution of error in elevation to the uncertainty...
Bumble bees provide vital pollination services in both native and agricultural landscapes. However, in recent years, bumble bee populations have experienced global population declines. The primary causes of these declines have been attributed to the environmental impacts of pathogens, pesticide use and habitat fragmentation. While research has examined the impacts...
This study investigated carbon dynamics in the hyporheic zone of a steep, forested catchment in the Cascade Mountains of western Oregon, USA. Water samples were collected monthly from a headwater stream and well network during baseflow conditions from July to December 2013 and again in March 2014. We also sampled...
This dissertation uses manipulative experiments to explore amphibian-Bd infection dynamics. Although there has been almost two decades research since the discovery of Bd, many questions still remain regarding what conditions mediate chytridiomycosis virulence. My research shows how certain host and pathogen factors can influence disease virulence. Identifying how host and...
The links between forests, streamflow, and climate are poorly understood. Despite hundreds of studies over the past 60 years, fundamental questions of forests' effects on the hydrologic cycle remain unanswered. The hydrological cycle involves mutually-dependent biological and physical processes that operate at multiple scales of time and space, and this...
Emerging infectious diseases are increasing globally and are a threat to human, wildlife, and ecosystem health. The emerging fungal pathogen, Batrachochytrium dendrobatidis (Bd), or amphibian chytrid fungus, is associated with worldwide amphibian population declines and extinctions. Bd has been found on every continent where amphibians exist and has been documented...
Species declines and extinctions have been recorded across taxa as evidence of an ongoing global biodiversity crisis. Amphibians are at the forefront of these declines with nearly one third of amphibian species estimated to be at risk of extinction. While many factors contribute to population declines and extinctions, the role...
Rapid rates of biodiversity loss have supported the notion that Earth is experiencing a sixth major extinction event. The causes of worldwide biodiversity loss are multifaceted and context dependent. One of the most prominent groups experiencing population declines and extinctions are amphibians. Several pathogens and their associated diseases are especially...
The ongoing worldwide loss of biodiversity has been described as a "biodiversity crisis," "the Anthropocene defaunation," and alternatively "an extinction spasm." More recently, many scientists have come to the conclusion that we are witnesses to Earth's sixth major mass extinction event, which has the potential to fundamentally alter basic ecological...
Infectious diseases are a growing concern for both humans and wildlife. The negative effects of infectious disease have been exemplified by the recent global amphibian population declines associated with disease outbreaks. Although multiple pathogens and factors play a role in these declines, the aquatic fungal pathogen, Batrachochytrium dendrobatidis (Bd), has...
Emerging infectious diseases impact both human and wildlife populations. Infectious agents, in particular the aquatic fungus Batrachochytrium dendrobatidis (chytrid), have an influential role in driving global amphibian population declines. The emergence of the chytrid fungus has aspects of both geographic spread as well as climate shifts altering environmental conditions and...
A comprehensive tribal-level classification for the world's subfamilies of Hesperiidae, the skipper butterflies, is proposed for the first time. Phylogenetic relationships between tribes and subfamilies are inferred using DNA sequence data from three gene regions: 943 bp of cytochrome oxidase subunit I (COI) (in the mitochondrial genome), 739 bp of...
The causes of the global biodiversity crisis are varied and complex. Anthropogenic threats may act in isolation, or interact additively or synergistically with each other or with natural stressors to affect sensitive taxa. The recent emergence of many infectious diseases in wildlife has brought attention to the role of disease...
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Andrew R. Blaustein
The causes of the global biodiversity crisis are varied and complex
I examined two amphibian communities to assess factors
that may impact amphibian biodiversity. The results suggest
that the potential factors which influence the maintenance
of amphibian biodiversity are multi-faceted and thus,
attempts to understand these factors must reflect these
complexities.
I investigated factors that influenced the susceptibility
of western toad...
Samples of benthic organisms off the coast of Oregon, taken
from depths varying from 50 to 2900 meters, have been analyzed in
terms of diversity at a given station, and similarity and ecological
distance to other stations. Estimates of epifauna abundance were
also made. In the analysis an important distinction...
The current rate of global biodiversity loss and extinctions is unparalleled and a major concern. Freshwater organisms are facing particularly rapid rates of biodiversity loss. Amphibians, which require an aquatic environment for part of their life cycle, are one of the most vulnerable vertebrate groups. Amphibians are experiencing population declines,...
Animals can be naturally exposed simultaneously to multiple stressors. These include habitat changes, contaminants, diseases, invasive species, parasitism, and predation. Exposure to various combinations of biotic and abiotic stressors may induce behavioral changes that affect the way an individual interacts within its environment.Like other groups of organisms, amphibians are exposed...
A multidisciplinary western Beaufort Sea Ecological Cruise
(WEBSEC) was conducted from August 15 to September 20, 1971.
During the cruise, one hundred ninety-nine 0.1 m² Smith-McIntyre
grabs samples were taken at forty stations located on the continental
shelf and slope of the western Beaufort Sea. The Gammaridean
Amphipoda and Cumacea...
Plant-pollinator mutualisms are one of the most prevalent and economically important mutualisms in nature. Like many other ecological systems, plant-pollinator communities are threatened by anthropogenic activity, both directly (e.g., habitat conversion and fragmentation) and indirectly (e.g., climate change). While we are aware of many of the activities that adversely impact...
Contemporary environmental change encompasses massive biodiversity loss and
increasing numbers of emerging diseases worldwide. As part of a global biodiversity
crisis, amphibians are disappearing at unprecedented rates. Batrachochytrium
dendrobatidis is an emerging infectious pathogen prominently associated with many
declines. Chapter 1 reviews the past decade of research on this system...
The tadpoles of several anuran species with groupforming
larvae are relatively unpalatable to many of
their potential predators. To more fully understand the
role of palatability and its relationship to group
formation as an antipredator defense in anuran amphibian
larvae, I investigated the palatabilities of the larvae
of three species...
Biogeochemical mechanisms employed by key organisms, or symbiotic associations of organisms, transform the function and structure of their environment through processes recognized as ecosystem engineering. This dissertation seeks to investigate organism-ecosystem interactions that serve globally significant ecological functions in marine systems and impact how systems respond to environmental change. Using...
This dissertation's three essays explore the effects of climate change on land use
changes in the U.S., how future land areas in all major land uses change by projecting
land use at the regional scale under two IPCC climate change scenarios. Investigate how
and what role should carbon sequestration plays...
Deep-sea chemosynthetic ecosystems remain a frontier in marine science. Essential to their role in the ocean ecosystem are endosymbiotic bacteria which support larger megafauna, including the widespread symbiont-bearing Vesicomyid clams. The diversity and characteristics of these symbionts in these clams is only just beginning to be understood with technological advances...
Looking to the natural world for insight into medical innovations is currently understudied and possibly underappreciated in the field of medicine. Natural environmental adaptations seen in wild animals can provide both inspiration and scientific realization for the future of human medicine. As humanity faces a global organ shortage crisis, research...
Metabolic defects within the different tissues and cell types of the eye give rise to many human ocular diseases. Polymorphisms in the Cytochrome P450 (CYP) family have been associated with many ocular disorders, particularly Cytochrome P450 1B1 (CYP1B1). Mutations in CYP1B1 have been linked to ocular diseases such as Primary...
When wheat is exposed to rain in the period before harvest, it sometimes causes the problem of pre-harvest sprouting (PHS). Wheat that undergoes sprouting has poor end-use quality and is less valuable. In recent years, the U. S. Pacific Northwest (PNW) has experienced increased summer showers sometimes causing widespread PHS....