A comparative investigation of the phenotypic properties of environmental and clinical strains of the lactose-positive human pathogen, Vibrio vulnificus, revealed that they are indistinguishable in traits commonly used for identification in clinical and public health laboratories. It has also been confirmed that there are other strains of undefined Vibrio spp.,...
Fish diseases and various parameters associated with disease
caused mortality of fish were monitored at the Oregon State University
Marine Science Center and at a private mariculture facility on
Yaquina Bay during a period of five years. Nearly all disease problems
observed were caused by Vibrio anguillarum and Vibrio spp....
The purpose of this study was to find what effect temperature
and immunization has on the phagocytic activity of fish leukocytes
against certain disease causing bacteria. Also proposed was the
isolation and characterization of a leukocytolytic factor produced by
one of these bacteria, Aeromonas salmonicida.
Investigations revealed that temperature had...
The Mx protein family of rainbow trout (Oncorhynchus mykiss) was characterized at the molecular level. With primers derived from a partial sequence of Perch (Perca fluviatis) Mx genomic DNA, a partial rainbow trout Mx genomic DNA sequence was obtained by polymerase chain reaction (PCR) amplification. All salmonid fish investigated contained...
Cooperative behaviors in bacteria are increasingly appreciated for their relevance to microbial ecology and utility as model systems for social evolution. One example is the secretion of siderophores, a structurally diverse group of compounds that chelate extracellular iron. Siderophore production is considered cooperative because the benefits can be shared with...
Of the 14 strains of Chondrococcus columnaris examined, 4
produced antagonistic substances that inhibited the growth of other
strains of this species. The antagonistic substance produced by
strain 3-P63-12 was examined in greater detail. Since the inhibitory
substance had an extremely narrow spectrum of activity, and
was not transmissible in...
Comparisons were made of the abilities of Streptococcus lactis,
Streptococcus cremoris and Streptococcus diacetilactis bacteriophages
to endure various laboratory isolation and storage treatments.
Neutralization of Cottage cheese whey containing phages offered no
survival advantage over unneutralized samples, refrigeration of
neutral and acid whey samples increased the survival of only the...
The focus of this thesis is to design, characterize, and apply novel computational methods and molecular systems to interrogate heterogeneous human gut microbiome-related phenomena. In Chapter 2, I design, implement, and characterize a method for embedding co-occurrence patterns derived from massive 16s amplicon datasets. I use this method to 1....
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...
The regulation of ergosterol biosynthesis in yeast has been
studied. The system has been examined for the presence of an end-product inhibition. Both anaerobically and aerobically grown cells
have been examined for this effect. A feedback inhibition of sterol
synthesis has been shown, but it appears to be a secondary...
Gut-brain communication consists of bidirectional routes between cognitive centers of the brain and peripheral intestines. This bidirectional communication is the result of the interplay between enteroendocrine cells (EECs), enteric nervous system, central nervous system, the vagus nerve, and our microbiota. Multiple studies have associated gut microbial dysbiosis with neurological disorders...
Juvenile coho salmon (Oncorhynchus kisutch) were orally
immunized against the bacterium Flexibacter columnaris (formerly
Chondrococcus columnaris), the causative agent of columnaris disease
in fish, with a vaccine-food preparation containing formalin-killed
cells. Fish immunized for 1, 2, 3, and 4 months were challenged
with selected concentrations of F. columnaris by exposure...
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...
This project was initiated to find a practical way of
identifying the volatiles and monitoring their relative concentrations.
Special attention was given to the identification
of the organic acids.
Volatile compounds produced in a swine confinement
building were trapped by porous polymers, Porapak Ω and Tenax
GC, and identified by...
The viral family Arenaviridae includes a number of viruses that can cause hemorrhagic fever in humans. Arenavirus infection often involves multiple organs and can lead to capillary instability, impaired hemostasis, and death. Preclinical testing for development of antiviral or therapeutics is in part hampered due to a lack of an...
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 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...