Bioremediation in the vadose zone is unpredictable because of poor understanding of factors influencing microbial growth in this environment. A lab-scale experimental system was developed to examine, noninvasively, interactions between microbial growth, water flow, and solute transport in unsaturated porous media. Measurements of microbial colonization, and its impact on hydrology,...
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...
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...
This thesis presents novel findings regarding
symbiotic, physiological, and antigenic characteristics of
representatives from an indigenous soil-borne population
of Rhizobium meliloti. Nodules were sampled from 'Vernal',
'Anchor', and 'Saranac' alfalfa, and the isolates analyzed
serologically. Rhizobium meliloti serogroup 31 was
identified as a dominant nodule occupant, with a greater
and...
Agronomic and microbiological studies were conducted on "Anchor" alfalfa (Medicago sativa L.) established from uninoculated seed on three Aridisols in central Oregon. Significant responses to 230 Kg N per ha (NH₄NO₃), which was applied in mid-April and after each first and second harvests, were observed in yield parameters of the...
The objectives of this thesis were to evaluate the responses of soil microbial communities to physical and chemical disturbances, and associate these responses with soil functional stability and changes in soil quality. The first study consisted of application of heat shocks (HS) to soils with contrasting land use history to...
Complementary methods of strain identification were sought to
delineate the composition of the population of Rhizobium trifolii
found in nodules of Trifolium subterraneum L. when exposed to an
Abiqua silty clay loam (Cumulic Ultic Haploxeroll) containing a
resident population of R. trifolii. Sodium dodecyl sulfate
polyacrylamide gel electrophoresis (SDSPAGE) was...