Trimethylamine-N-oxide (TMA-0) reductase activity of resting cells of Escherichia coli was inhibited by tetrasodium ethylenediaminetetraacetate (Na₄EDTA), benzoic acid (BA), and methylparaben (MP). The 50% inhibitory concentrations of Na₄EDTA, BA, and MP were 20.2, 1.2, and 32.4 mM, respectively. BA at pH 6.5 or below most effectively inhibited the TMA-0 reductase. Sorbic acid (SA), up to 0.70 mM, had no effect on TMA-0 reductase activity, but SA inhibited the growth and subsequent TMA production in E. coli at or above 0.35 mM. / Graduation date: 1981

An original study was undertaken in the pharmacy and at the nursing unit simulating conditions of actual use to determine contamination rates for intravenous fluids in glass bottles and flexible plastic bags.

Lactation provides the singular source of nourishment to the offspring of mammals. This nutrition source also contains a diverse microbiota affecting the development and health of the newborn. Here, we examined the milk microbiota in water deer (Hydropotes inermis, the most primitive member of the family Cervidae), reindeer (Rangifer tarandus, the oldest semi-domesticated cervid), and the dairy goat (Capra aegagrus, member of the family Bovidae), to determine if common milk microbiota species were present across all three ruminant species. The results showed that water deer had the highest bacterial diversity, followed by reindeer, and then goat. Unifrac distance and correspondence analyses revealed that water deer harbored an increased abundance of Pseudomonas spp. and Acinetobacter spp., while milk from reindeer and goat was dominated by unclassified bacteria from the family Hyphomicrobiaceae and Bacillus spp., respectively. These data indicate significant differences in the composition of milk-based bacterial communities. The presence of Halomonas spp. in three distinct co-occurrence networks of bacterial interactions revealed both common and unique features in milk niches. These results suggest that the milk of water deer and reindeer harbor unique bacterial communities compared with the goat, which might reflect host microbial adaptation caused by evolution.

A convergent synthesis of epothilone B that generates all seven of its asymmetric centers in a completely stereoselective fashion has been completed. Key reactions include an anti-Felkin aldol condensation to set the C6 and C7 stereochemistry, a directed α-hydroxylation to install the C15 (S)-hydroxyl substituent, and a Wittig condensation to join two main subunits via C-C bond formation at C9-C10. In addition, through modifications to the C9-C10 region of the macrolide, several novel and cytotoxic epothilone analogues were synthesized. Bioassay data comparing the antiproliferative activity and tubulin polymerization of the analogues with epothilone B, epothilone D, and paclitaxel showed that the synthetic analogues were less potent than their natural counterparts. / Graduation date: 2005

Plants are a major force shaping how ecosystems function, including non-native plants. The effects that non-native plants have on ecosystem properties and processes can be particularly important as invasive plants are associated with changes in nitrogen and carbon cycling Plants can also indirectly affect ecosystem processes through their influence on the soil microbial community and different plants are associated with different microbial communities. The legacies produced by invasive plants can be long-lasting and inhibit the restoration of damaged ecosystems. Because of the central role of soil fungi in ecosystem processes, I examined how fungal abundance and community composition were altered by non-native plants, and the persistence of these changes. Specifically, I examined how two different cases of invasion by non-native species affected soil fungi over three years compared to soil fungi in native, undisturbed sites. I further tested how the soil fungi responded to the removal of the non-native plants and to inoculation with local native microbial communities. Legacy effects of land use history on soil fungal abundance and community composition were found in these central Florida communities. There were substantial differences in soil fungal abundance and community composition in disturbed and pasture sites compared to native scrub, and these differences persisted for three years after non-native grasses were removed. Not only did the grass-dominated pasture and disturbed sites differ from the undisturbed native shrub-dominated ecosystem, they differed significantly from each other, indicating that the different non-native grasses and other specific changes associated with each land use played a role in soil fungal communities. The combined results of this study have implications for restoration ecology. The current dependence of the fungal community on land use and the associated non-native species invasions (along with other analyses done in this system) suggest that a different approach to restoration is required here to overcome the observed legacy effects. / text

The traditional colloid filtration model has been recognized to not fully describe transport of microorganisms in porous media under many conditions. Potential reasons for the discrepancies between colloid filtration theories and observed data are summarized into three aspects in the dissertation, including physicochemical heterogeneity, a blocking effect in the attachment process, and irreversible straining. A new transport model is developed to incorporate these non-ideal phenomena. First, both the collision-efficiency coefficient and the detachment-rate coefficient are formulated as probability density functions with log-normal distributions to represent physicochemical heterogeneity of both microbial and porous-medium grain surfaces. Second, the blocking effect is represented by appending a modified random sequential adsorption (RSA) function to the kinetic rate equation. Third, a semi-empirical equation is developed to describe the straining effect.The new model is then evaluated with a series of sensitivity analyses and illustrative applications to measured data. Sensitivity analysis on the role of probability density function (PDF) in collision efficiency and detachment rate coefficient shows that heterogeneity causes longer tailing in breakthrough curves, This effect is controlled by the implementation of the PDF in the detachment rate coefficient because the lower values among a series of detachment rate coefficients delay detachment. Straining phenonmena have received more and more attentions for protozoa transport. The new semi-empirical straining equation derived in the dissertation provides reasonable matches to the colloid data and cryptosporidium data. The Blocking effect is another process of concern for microbial transport, as shown in the analysis of microsporidium column experiments herein. The new model also proved to be successful for simulating MS-2 virus transport. The work presented will help enhance our understanding of biocolloid transport in porous media.

Bibliography: leaves 235-250. / 297 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Aims to develop the process for Poly-[beta]-hydroxybutyrate recovery from recombinant E. coli, using homogenization and centrifugation as the basic unit operations, with effects directed to reduce the Poly-[beta]-hydroxybutyrate overall production cost. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemical Engineering, 1999

Thesis (Ph.D.)--University of Adelaide, Dept. of Chemical Engineering, 1999. / Bibliography: leaves 235-250.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1960. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 42-49).

Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 287-292).