The Willamette River, one of only 14 American Heritage Rivers, flows through the most densely populated and agriculturally productive region of Oregon. Previous biological monitoring of Willamette River fish detected elevated frequencies of skeletal deformities in fish from certain areas of the lower (NP [NP], rivermile [RM] 26-55) and middle...
Mycobacterium avium is an intracellular pathogen that is associated with disseminated
infection, especially in patients with acquired immunodeficiency syndrome (AIDS). It
appears that patients with AIDS acquire M. avium mostly through the intestinal tract,
and that bacteria enter the intestinal wall at the terminal ileum. Previous studies have
found that...
Biological agents and their products commonly cause foodborne illnesses. In the United States it is estimated that there are over 76 million cases of foodborne illnesses each year, resulting in an economic loss of approximately $40 billion. These high figures demonstrate the need for bioassays that display a rapid and...
Streptococcus gordonii is a bacterial species that naturally colonizes the oral cavity of most healthy humans. It resides in the mouth as an adherent to dental surfaces and, with few exceptions, does not cause disease in individuals it inhabits. It possesses qualities that encourage its use as a vector to...
Ceratomyxa shasta is a myxozoan parasite of salmonids and requires the freshwater polychaete, Manayunkia speciosa to complete its life cycle. The parasite’s distribution is currently limited to the Pacific Northwest region of North America and has been reported to cause substantial losses of both wild and hatchery salmonids. The spatial...
The majority of our modern understanding of bacterial pathogenesis is based on the strategy that involves screening bacterial genomes for the presence of the genes encoding pathogenic factors, and analysis of these genes via forward and reverse genetics. Chlamydiae represent a unique group of pathogenic bacteria in which it is...
In this thesis, I studied the translation of dengue virus RNA using a luciferase reporter gene system in Vero cells. The dengue reporter mRNA construct, which harbors 5´-terminal viral nts and 3´-terminal nts, could be translated efficiently compared to an alpha globin reporter construct. The 5´-cap structure and 3´-untranslated region...
Francisella tularensis is a gram-negative facultative intracellular
coccobacillus that primarily infects macrophages. The causative agent of tularemia,
this bacterium is considered among the most infectious organisms known, requiring
fewer than ten organisms to cause disease. Although ubiquitous in nature,
transmission to humans is rare but can occur via insect bites,...
Standard methods of measuring fecal pollution in water do not distinguish between human and non-human sources. Molecular technology enabled the development of host-specific markers that distinguish fecal sources. Human specific PCR primers, HF183F and HF134F, were designed based on phylogenetic analyses of partial 16S rRNA gene sequences from the Bacteroidales...
Clostridium perfringens type A isolates producing enterotoxin (CPE) are an
important cause of both food poisoning (FP) and non food borne gastrointestinal
diseases (NFBGID) in both humans and animals. C. perfringens type A food
poisoning is caused by isolates carrying the CPE encoding gene (cpe) on the
chromosome while the...
Aquatic fecal contamination from non-point sources impairs environmental health and serves as a vehicle for transmission of waterborne disease, resulting in economic losses worldwide. Accurate methods of diagnosing fecal pollution and its source are needed to prevent human exposure, remediate pollution, and reduce economic impacts. In order to obtain this...
The ability to move towards favorable environmental conditions, called chemotaxis, is common among motile bacteria. In particular aerotaxis has been extensively studied in Escherichia coli. Three putative aer gene homologs were identified in the V. cholerae genome designated VCAer-1 (VC0512) VCAer-2 (VCA0658), and VCAer-3 (VCA0988). Deletion analyses indicated that only...
In order to produce infectious virus progeny, vaccinia virus (VV)
undergoes morphogenic proteolysis to regulate the structural rearrangements of
virus particles. Several of the major structural precursor proteins of VV are
cleaved at a conserved Ala-Gly-X (where X is any amino acid) motif by the VV
I7L core protein proteinase...
Vaccinia virus is the prototypic member of the Orthopoxvirus genus. It undergoes a complex replication process where a key step in the transition from immature virion to intracellular mature virion is the cleavage of the major core protein precursors. The product of the I7L open reading frame (ORF) is a...
The Baculoviridae comprise a diverse group of occluded DNA viruses that contain large double-stranded DNA genomes of 80 - 180 kb and may encode up to 180 gene products. To understand how baculoviruses replicate and process their genomes and the gene products that are involved in these events, a series...
Chlamydiae are obligate intracellular bacteria that infect a variety of
eukaryotic hosts and affect normal host processes. Within host cells, their
developmental cycle takes place inside non-acidified vacuoles termed inclusions. An
inclusion membrane composed primarily of secreted chlamydial synthesized proteins
called Incs encloses the inclusion. At this location, Incs have...
Candidatus Pelagibacter ubique is the first cultured representative of the SAR11 clade, a clade that is found throughout the oceans and accounts for approximately 25% of all bacterial cells [1]. It has a streamlined genome that is the smallest of any known free-living organism. In this study the complete genome...
Clostridium perfringens type A isolates, an anaerobic enterotoxigenic spore forming bacterium, are the third leading cause of food-borne disease in the United States. Factors that contribute to the virulence of C. perfringens include the ability of the bacterium to form heat resistant spores and to produce an enterotoxin (CPE). Although...
The regulation of monooxygenase enzymes has been demonstrated in bacteria that grow on methane and long chain-length alkanes (>C10). Less is known about monooxygenase regulation in short chain alkane oxidizing bacteria that grow on intermediate chain-length alkanes C2-C10. This dissertation focuses on the regulation of butane monooxygenase (BMO) expression and...
There have been many studies that describe the protective degradation or metabolism of potentially harmful plant toxins, such as, mimosine from Leucaena leuconcephala, pyrrolizidine alkaloids from tansy ragwort (Senecio jacobaea), oxalate and some mycotoxins by rumen microbes. There are many cases of plant-related toxicoses suffered by ruminant animals where there...
Chemical and microbial analyses were made at four seasonal intervals on soil horizons under red alder, conifers, and mixed
alder-conifers at the Cascade Head Experimental Forest, established in 1937 by the U. S. Forest Service near Otis, Oregon.
Microbial analyses showed that although plate counts of molds and bacteria fluctuated...
The F13L protein is the major envelope antigen of vaccinia virus, the prototypic member of the Orthopoxvirus genus. F13L is 372 residues in length and is essential for the formation of wrapped forms of virus. F13L contains a number of potential functional domains including a palmitylation site, a phospholipase domain...
The chemolithoautotrophic nitrite oxidizing bacteria (NOB) participate in the
biogeochemical cycling of nitrogen by catalyzing and conserving energy from the
oxidation of nitrite (NO₂-) to nitrate (NO₃-) via a nitrite oxidoreductase (NXR). The
main objective of this work was to comparatively annotate and analyze the genome
sequences of Nitrobacter winogradskyi...
Optimum growth temperatures were determined for nine strains of Streptococcus thermophilus and ten strains of Lactobacillus bulgaricus, all commercial yogurt or yogurt
starter isolates. Optimum growth temperatures ranged from 35 C to 42 C for S.thermophilus strains, averaging 38.6. Optimum growth temperatures for L.bulgaricus strains ranged from 43 C to...
At present all vaccines for fish are primarily delivered either by injection or immersion which introduces added stress and labor. A more attractive method of vaccine delivery is oral administration using an enteric protection system, Enteric Coated Antigen Microspheres (ECAMs), which can be utilized for a variety of antigenic forms....
2,4,6-Trinitrotoluene (TNT) has been the common munitions used in the world and is an environmental contaminant that is amendable to reductive transformation reactions. The rumen is an extremely reductive environment containing diverse microbial populations. There are 21 pure culture ruminal bacteria species in culture collection, these were tested for the...
For the past twenty-seven years, Human Immunodeficiency Virus (HIV)/Acquired Immunodeficiency Syndrome (AIDS) has become a worldwide pandemic. Due to the properties of HIV, such as its fast replication rate and error-prone reverse transcriptase, researchers have been unsuccessful in finding a cure or vaccine. Researchers have, however, developed a treatment regimen...
Morphological, cultural, biochemical and serological characteristics of
33 bacterial strains, thought to be similar to Cytophaga psychrophila, the
causative agent of bacterial cold-water disease were compared. Bacterial
strains identified as C. psychrophila were obtained from diseased salmonids
collected at widely separated geographic locations, and from fish with
pathological signs different...
The purpose of this study was to characterize Cytophaga
psychrophila isolates obtained from coho fingerlings with low temperature
disease collected at selected hatcheries in Oregon. In
addition, cultures thought to be related to this bacterium were
isolated from Siletz Hatchery water, deformed juvenile and spawning
adult coho salmon, rainbow and...
A plan for the reestablishment of anadromous salmonid stocks into waters above the Pelton Round Butte Hydroelectric Project (PRB) located on the Deschutes River, Oregon has been under development since 1996. The PRB complex, starting at river kilometer (Rkm) 103, blocks the further upstream migration of anadromous salmonids into upper...
Current detection methods for bacterial contamination rely on structure based detection of proteins and nucleic acids. While these methods are easy to use and reliable, they cannot evaluate the toxicity of a sample and the potential to cause disease. Previously, erythrophore cells derived from Betta splendens had been suggested as...
Cell-based biosensors are function-based detectors that use the physiological response of a living cell to sense biologically stimulating agents. This emerging technology extends the application of current detection methods by reporting on the toxicity of a sample and the potential to cause disease. Previously, Betta splendens erythrophores have been described...
Tumor necrosis factor alpha (TNF α) and interferon gamma (IFN γ) were initially recognized as inflammatory mediators produced by immune cells in response to infectious agents or foreign material. (1,5) However, over the past decade much research in mammalian species has indicated that these proteins also play key roles in...
The immune toxicity of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has been studied for over 35 years, but only recently has the profound immune suppression associated with TCDD exposure been linked to induction of regulatory T cells (Tregs). The effects of TCDD are mediated through binding the aryl hydrocarbon receptor (AhR), a ligand-activated transcription...
A technique that uses hypotonic lysis of erythrocytes was optimized for the purification of leukocytes from the peripheral blood and anterior kidney (pronephros) of rainbow trout Oncorhynchus mykiss. Comparisons of initial blood dilution (1:2, 1:4, and 1:6) and the time of exposure to hypotonic conditions (10, 20, and 40 s)...
The ability of Flexibacter columnaris to attach to fish
cells was studied. Four of the five bacterial strains
tested were able to adhere to fish cells derived from four
different fish species. The attachment of these strains
in vitro required magnesium but was not affected by
increasing the incubation temperature...
Ceratomyxa shasta is a myxozoan parasite that infects salmonid fishes causing the disease ceratomyxosis that is characterized by severe hemorrhage and necrosis of the intestine and death of the fish host. Ceratomyxa shasta is endemic to the Pacific Northwestern United States and Canada, where epizootics are reported for both wild...
Relationships among myxozoan parasites of the order Multivalvulida were examined through comparative DNA sequence analysis. Members of this group of parasites is known for the damaging effects they have on their fish hosts, especially commercially important species. Most species infect muscle, where they form cysts and many release proteolytic enzymes....
The anaerobic and highly reductive conditions found in the ovine rumen are considered favorable for the degradation of the nitroaromatic explosives such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). In this study, we used stable-isotope-probing to determine the bacteria responsible for the degradation of RDX in the rumen. Results indicate 10 μg mL⁻¹ (45...
Nearly 3000 juvenile Chinook (Oncorhynchus tshawytscha) and coho (O. kisutch) salmon captured in nearshore waters off the coasts of Washington and Oregon from 1999-2004 were tested for infection by Renibacterium salmoninarum, Nanophyetus salmincola, and skin metacercariae. First, three quantitative PCR primer/probe sets were compared for detection of R. salmoninarum; amplification...
The bacteriophage receptor of lactococci was found on the cell
walls. A carbohydrate analysis of the cell walls from phage-resistant
mutants of L. lactis subsp. cremoris KR with reductions in phage binding
indicated that a loss of galactose correlated with a loss in binding
and infection of all phage tested:...
Clostridium perfringens is a pathogenic anaerobic bacterium able to produce more than 17 toxins, allowing C. perfringins to cause a wide variety of diseases in humans and animals. Beside toxins production, C. perfringens able to form a highly resistance spores can survive in the environments for years. These spores are...
The myxozoan parasite of salmonids, Ceratomyxa shasta, is established throughout the Klamath River, CA-OR, with high parasite densities below the series of dams and above the dams (upper basin) in the northernmost tributary, the Williamson River (WMR). Two objectives were designed to address concerns about C. shasta effects on reintroduced...
Diseases caused by parasites are recognized as significant sources of mortality in wild fish populations. I assessed the impacts of multispecies parasitism on a threatened stock of juvenile coho salmon (Oncorhynchus kisutch). A crucial prerequisite to this research was proper identification of parasites, which can be difficult for species lacking...
Myxobolus cerebralis, a myxozoan parasite that infects almost all species of wild and cultured salmonids, was first identified in northeastern Oregon in the Lostine River in 1986. Fish that are heavily infected with M. cerebralis develop whirling disease, which was determined to be the cause of catastrophic declines in rainbow...
Cyclic nitramines released into all environmental compartments through anthropogenic activities are toxic and possibly carcinogenic and mutagenic. Soils on military ranges, located throughout the world in various climatic regions and close to human activities, are especially susceptible to cyclic nitramine contamination. The properties of soils on military ranges will directly...
Pseudomonas aeruginosa is an environmental bacterium as well as an opportunistic pathogen that primarily infects immunocompromised individuals, including those suffering from cystic fibrosis. The density-dependent regulation of gene expression via cell-to-cell communication, also termed quorum sensing (QS), is an important virulence determinant in this organism. Generally, P. aeruginosa uses three...
Clostridium perfringens is the causative agent of gas gangrene and the 3rd most common cause of type A food borne disease in the United States. Critical to the pathogenicity of C. perfringens is the ability of this bacterium to produce highly resistant, metabolically dormant spores that can resume metabolic function...
We are studying the impacts of parasites on threatened stocks of Oregon coastal coho salmon (Oncorhynchus kisutch). In our previous studies, we have found high infections of digeneans and myxozoans in coho salmon parr from the lower main stem of West Fork Smith River (WFSR), Oregon. In contrast parr from...
Multiple analytical techniques were used to evaluate the impact of multiple parasite species on
the mortality of threatened juvenile coho salmon (Oncorhynchus kisutch) from the West Fork Smith
River, Oregon, USA. We also proposed a novel parsimonious mathematical representation of
macroparasite distribution, congestion rate, which i) is easier to use...
Wine has recently been shown to be a possible protective agent against
microbial foodbome illness. The chemical environment of wine makes it difficult, if
not impossible, for microorganisms to survive. The low pH, high concentration of
organic acids, relatively high ethanol concentrations, and the potential for high levels
of sulfur...
Pacific rockfish experience high discard mortality when captured owing to a condition called barotrauma,which is caused by the change in pressure during capture. This condition appears to be species specific at the macroscopic level; however, little is known about the microscopic tissue-level effects of barotrauma. Determining whether tissue-level injuries are...
Waterborne fecal contamination poses serious risks to human health and can disrupt aquatic ecosystems. Molecular marker methods are widely used to identify and, in some cases, quantify the sources of contamination and guide management decisions regarding water resource protection. However, methods to detect some likely sources of fecal contamination such...
Crown gall disease is caused by the ubiquitous soil bacterium Agrobacterium tumefaciens which transfers a portion if DNA (T-DNA) into the plant cell. Preventing infection by using the biocontrol strain Agrobacterium radiobacter K84 is currently the only defense for crown gall. Two different resistance strategies were examined in this work....
Mycobacterium avium is a ubiquitous environmental organism found in both water and soil. It can cause disease in patients with previous pulmonary conditions, as well as immunosupressed patients, with the most prevalent being AIDS patients. Studies have indicated that passage through amoeba, a common environmental protozoa, increases virulence of M....
L1R, a myristylated late gene product of vaccinia virus, is essential for formation of infectious intracellular mature virions (IMV). In its absence, only viral particles arrested at an immature stage are detected and no infectious progeny virus are produced. Previous studies have shown that the L1R protein is exclusively associated...
Freshwater cyanobacterial blooms are a nuisance and health threat in the Pacific Northwest. The accepted methods of characterizing these blooms by microscopic cell counts cannot differentiate between toxic and non-toxic strains of the cyanobacterium Microcystis. Also, there is limited understanding of freshwater cyanophage that may control bloom dynamics. In order...
Social behavior leading to the production of common goods is prone to exploitation. One such behavior in Pseudomonas aeruginosa is quorum sensing (QS), by which the bacteria produce signals to regulate extracellular common goods. Exploitation comes in the form of cheaters which have a mutation in the central quorum sensing...
Novel mucosal vaccines (LL-M2e, LL-HAe, SG-HAe) were constructed from live, non-pathogenic Lactococcus lactis or Streptococcus gordonii that express conserved regions of HA or M2 antigens from avian influenza virus (AIV) A. All three vaccines evoked antigen-specific serum immunoglobulin G (IgG) responses in vaccinated chickens. The addition of the adjuvant cholera...
Aquifers are an important storage location and source of fresh groundwater. They may become polluted by a number of contaminants including mobile divalent radionuclides such as strontium-90 which is a byproduct of uranium fission. A method for remediating such divalent radionuclides is sequestration through co-precipitation into calcium carbonate. Calcium carbonate...
The pathogen Vibrio cholerae uses cations as a primary currency of virulence
and environmental persistence, using gradients of those cations to move, acquire
nutrients, and control virulence gene expression. An understanding of the overlapping
roles of bioenergetics and chemotaxis in the virulence and environmental survival of
V. cholerae issues from...
A comparison of the agglutinating and precipatiating
antigens of Enteric Redmouth Bacterium (ERMB) was made.
There are two major and one minor agglutinating antigens
which describe two serotypes (I and II). Only serotype I
metabolizes sorbitol. A bacterin from serotype I cross
protected against a challenge of bacteria of serotype...
Detection of both biological and chemical environmental toxicants is essential in the assessment of risk to human health. Cell-based biosensors are capable of activity- based detection of toxicity. Chromatophore cells, responsible for the pigmentation of poikilothermic animal, have shown immense potential as cell-based biosensors in the detection of a broad...
Ceratomyxa shasta infects salmonids in the Pacific Northwest (PNW) of North America, occasionally causing losses in wild and captive populations. Host-specific parasite genotypes (O, I, II, III) were previously characterized molecularly using markers in the ribosomal DNA and phenotypically by type host in the Klamath River, CA/OR. This thesis sough...
Cyanobacteria are rich in biologically active secondary metabolites, many of which have potential application as anticancer or antimicrobial drugs or as useful probes in cell biology studies. A Jamaican isolate of the marine cyanobacterium, Lyngbya majuscula was the source of a novel antifungal and cytotoxic secondary metabolite, hectochlorin. The structure...
Members of the family Chlamydiae cause a wide range of diseases. Chlamydia trachomatis and C. pneumoniae are most commonly associated with human disease. C. psittaci and C. pecorum are largely animal pathogens, although C. psittaci can cause pneumonia in the elderly and immunocompromised. A vaccine against these pathogens is desirable,...
In recent years considerable interest has been shown in the diversity of ammonia-oxidizing bacteria in soil communities. The majority of the research has been carried out in Northern Europe where soils have received high atmospheric inputs of nitrogen over the past two centuries. In contrast, although much work has been...
Pseudomonas aeruginosa is an opportunistic human pathogen that infects immunocompromised individuals such as those suffering from burns or the genetic disorder cystic fibrosis. This organism utilizes a cell-cell communication mechanism known as quorum sensing (QS) to coordinate virulence gene expression and biofilm formation. It has three interconnected QS systems, namely...
The most abundant clone found in ribosomal RNA clone libraries obtained from the world's oceans belongs to the SAR11 phylogenetic group of environmental marine bacteria. Imaging and counting SAR11 bacterial cells in situ has been an important research objective for the past decade. This objective has been especially challenging due...
Interest in the distribution of Clostridium botulinum type E
was heightened by the sudden outbreak of human botulism from
smoked whitefish chubs and canned tuna fish in 1963. The question
arose as to how widely the organism is distributed among fish
and shellfish in the Northwest and what potential hazard...
Plant viruses have been instrumental in our understanding of the biophysical properties pertaining to non-enveloped icosahedral virus particles. A substantial amount of research has been performed over five decades on Turnip yellow mosaic virus (TYMV), arguably one of the most extensively studied icosahedral plant viruses and the type-member of the...
Microorganisms play key roles in ocean biogeochemistry. However, several
predominant groups of uncultured bacterioplankton thought to contribute to
important biogeochemical processes in the oceans are known primarily from gene
cloning studies. Although these studies have greatly expanded our view of
microbial diversity in the oceans, they are not quantitative and...
Marine bacteria from the SAR11 clade (class Alphaproteobacteria), specifically strains
HTCC1062 and HTCC7211, were characterized according to a polyphasic taxonomic approach.
Maximum cell densities and growth rates at various temperatures, salinities, and pH’s were
analyzed. Strains HTCC1062 and HTCC7211 were observed as having different growth
optimums. On the basis of...
Continental shelves located along eastern boundary currents occupy relatively small volumes of the world’s oceans, yet are responsible for a large proportion of global primary production. The Oregon coast is among these ecosystems. Recent analyses of dissolved oxygen at shallow depths in the water column has suggested increasing episodes of...
Lactic acid bacteria (LAB) play a significant role in the production of several food products for human consumption. Humans exploit and maximize the various benefits from LAB characteristics, especially in foods such as cheese, yogurt and other fermented products. More recently, research discovered that certain LAB, such as Lactococcus species,...
The purpose of this investigation was to compare some of the
properties of a spore-forming mutant of Bacillus cereus 569R with
the wild type. The strains were grown under identical conditions in
liquid medium. The mutant, strain 45, was characterized with
respect to growth rate, pH changes in the medium,...
Although IL-4 is a well-characterized multi-functional cytokine, its role as a survival factor in T cells is not completely understood. In an attempt to uncover IL-4-mediated survival, we studied caspase activation in primary mouse T lymphocytes undergoing death by neglect, activation-induced or steroid-induced cell death. Here, we identify the executioner...
The removal of dams on a river is one potential tool for the ecological restoration of native salmonid fishes. However, the removal of barriers also introduces risks, such as the introduction of fish pathogens into previously isolated populations. The proposed removal of four dams on the Klamath River, Oregon–California, provides...
We are conducting studies on the impacts of parasites on Oregon coastal coho salmon (Oncorhynchus kistuch). An essential first step is documenting the geographic distribution of infections, which may be accomplished by using different methods for parasite detection. Thus, the objectives of the current study were to (1) identify parasite...
With the expansion of the RNA world, antisense strategies have become widespread to manipulate nuclear gene expression but organelle genetic systems have remained aside. The present work opens the field to mitochondria. We demonstrate that customized RNAs expressed from a nuclear transgene and driven by a transfer RNA-like (tRNA-like) moiety...
Contamination of recreational and shellfish waters with fecal pollution is a major water quality issue with associated economic impacts and human health risks. Reliable fecal source identification and rapid, quantitative analyses are essential components of risk assessment. Enteric bacteria that are endemic to specific hosts have a potential role as...
Opakapaka (Pristipomoides filamentosus) is a snapper (family Lutjanidae) native to the waters around Hawaii. Recent population declines of this commercially important species have increased interest in the culture of this fish. Survival of this fish through the larval period in culture has been consistently low, usually not exceeding 2%. The...
Investigations into the phylogeny, genome size, and karyotype of microsporidian Nadeispora canceri were initiated to further characterize the organism. Isolates of N. canceri spores were obtained from both Dungeness (Cancer magisrer) and red rock crabs (Cancer productus). Analysis of the ssu rDNA sequence from spore isolates of the two crab...
Clostridium perfringens type A is the causative agent of a variety of histotoxic and enteric diseases. The ability of C. perfringens spores to germinate in vivo might be due to the presence of nutrient germinants in the host tissue and blood. In the current study, we investigated the ability of...
Reductive dechlorination of chlorinated ethenes is dependent upon suitable substrates promoting microbial activity and creating anaerobic conditions. At the periphery of active reductive dechlorinating zones combinations of lesser chlorinated ethenes should exist along with end products of the anaerobic metabolism that is driving reductive dechlorination. Potential end-products of anaerobic metabolism...
With rising concentrations of CO₂ in the Earth's atmosphere causing
concern about climate change, many solutions are being presented to
decrease emissions. One of the proposed solutions is to sequester excess
CO₂ in geological formations such as basalt. The deep subsurface is known
to harbor much of the microbial biomass...
A new high-throughput culturing (HTC) method using a low nutrient
heterotrophic medium (LNHM) has led to the isolation of many novel strains of
oligotrophic bacteria from marine ecosystems. Four strains belonging to a single
dade, HTCC2151, HTCC218OT, HTCC2178T and HTCC2188T, were isolated
from the coast of Oregon by the HTC...
Some positive-strand RNA plant viruses possess a transfer RNA-like structure (TLS) at the 3'-terminus of their genomic RNAs. The closest mimicry to tRNA is exhibited by the valylatable TLSs from tymoviruses and furo-like viruses, which are able to interact with key cellular tRNA enzymes: [CTP, ATP]:tRNA nucleotidyltransferase (CCA NTase), valyl-tRNA...
Most pathogens gain access to their host through mucosal surfaces. It is therefore desirable to develop mucosal vaccines that elicit an immune response to prevent this crucial first step in infection. Current mucosal vaccines are live attenuated strains of pathogens. More recent efforts have focused on the use of recombinant...
Because Ras signaling is frequently activated by major hepatocellular carcinoma etiological factors, a transgenic zebrafish constitutively expressing the kras(V12) oncogene in the liver was previously generated by our laboratory. Although this model depicted and uncovered the conservation between zebrafish and human liver tumorigenesis, the low tumor incidence and early mortality...
The myxozoan parasite Ceratomyxa shasta is a significant pathogen of juvenile salmonids in the Pacific Northwest of North America and is limiting recovery of Chinook (Oncorhynchus tshawytscha) and coho (O. kisutch) salmon populations in the Klamath River. We conducted a 5-year monitoring program that comprised concurrent sentinel fish exposures and...
Genomic analysis is a new approach for the characterization and investigation of novel genes, gene clusters, the function of uncharacterized proteins, and genetic diversity in microorganisms. These approaches are important for the study of chlamydiae, a system in which several genomes have been sequenced but in which techniques for genetic...
Vibrio cholerae has adapted to a wide range of salinity, pH and osmotic conditions, enabling it to survive passage through the host and persist in the environment. Among the many proteins responsible for bacterial survival under these diverse conditions, we have identified Vc-NhaP1 as a K+(Na+)/H+ antiporter essential for V....
Chlamydiae are obligate intracellular pathogens that cause several serious conditions within the human host. Many of the symptoms associated with infection are thought to stem from the development of aberrant, or persistent, chlamydiae. Factors leading to chlamydial persistence include deprivation of amino acids, the release of certain cellular factors, or...
Myxobolus cerebralis, a myxozoan parasite of salmonids, is the causative agent of whirling disease. The parasite is considered widespread throughout northeastern Oregon in the Grande Ronde and Imnaha River basins where threatened and endangered salmonid populations exist. The work presented in this thesis comprises several studies that assess the effects...