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Efficient Separation And Sensitive Detection Of Listeria Monocytogenes Using Magnetic Nanoparticles, Microfluidics And Interdigitated Microelectrode Based Impedance Immunosensor, Damira Ashimkhanovna Kanayeva

Graduate Theses and Dissertations

Listeria monocytogenes continues to be a major foodborne pathogen that causes food poisoning and sometimes death in immunosuppressed people and abortion in pregnant women. Nanoparticles have recently drawn attentions for use in immunomagnetic separation techniques due to their greater surface area/volume ratio and better stability against sedimentation in the absence of a magnetic field. Interdigitated microelectrodes and microfluidics make material transfer more efficient and biological/chemical interaction between the surface and solution phase much quicker. Magnetic nanoparticles (Fe3O4) with a 30 nm diameter were functionalized with rabbit anti-L. monocytogenes antibodies via biotin-streptavidin bonds and then amalgamated with target bacterial cells …

Tryptophan Anchored Peptides In Lipid Bilayer Membranes: Control Of Peptide Orientation And The Phase Behavior Of Cholesterol-Containing Ternary Lipid Mixtures, Johanna Maria Rankenberg

Graduate Theses and Dissertations

Model WALP peptides and "next generation" WALP-derived hydrophobic model peptides were employed to discover principles that govern protein-lipid interactions in biological membranes.

Ternary cholesterol-containing lipid mixtures were examined in the presence of WALP peptides of different lengths (acetyl-GWW(LA)_nLWWA-ethanolamide, with n between 3 and 8). Deuterium NMR spectra from labeled lipids reveal that WALP peptides may stabilize lipid ordered "raft" domains and therefore promote lipid phase separation, albeit to a minor extent. The results depend upon whether dioleolyl- or diphytanoyl-phosphatidylcholine is present as the fluid lipid component.

Several WALP peptides were modified to remove anchoring Trp residues from one …

Applications Of Site-Specific Recombination Systems In Transgene Expression And Marker Gene Removal, Mehmet Aydin Akbudak

Graduate Theses and Dissertations

Site Specific Recombination systems, such as FLP-FRT and Cre-lox, have been successfully used for site-specific gene integration and marker-gene deletion in plant systems. They are very useful tools in the integration of single-copy full-length transgene cassettes into the genome because the transgene integration via conventional methods often generate multi-copy locus. Such complex locus containing direct and inverted repeats of full-length and truncated copies of the transgene cassette generate aberrant RNA resulting in gene silencing. Therefore, for stable gene expression, a single copy transgene locus is preferred. However, even single copy locus sometimes succumbs to gene silencing. Although the mechanism is …

Intraspecific Variation In Two Cosmopolitan Myxomycetes, Didymium Squamulosum And Didymium Difforme (Physarales: Didymiaceae), Katherine Elizabeth Winsett

Graduate Theses and Dissertations

The myxomycetes (plasmodial slime molds or myxogastrids) are one of three groups considered to be true slime molds (class Eumycetozoa sensu Olive 1975). Two vegetative states--amoebae and plasmodia--along with a spore-producing fruiting body characterize the life cycle of the myxomycetes. These organisms are associated with decaying plant material and are found in all terrestrial habitats worldwide. A number of species are considered cosmopolitan, being found worldwide, where they are associated with a diversity of microhabitats and substrates. A review of the literature, including molecular investigations in all three groups of slime molds, is presented, and this is followed by four …

Analysis Of The Response Of Medicago Truncatula Calcium Oxalate Mutants To Abiotic Stress, Wayra Gabriela Navia-Gine

Graduate Theses and Dissertations

Calcium oxalate crystals are found in most plant species. In Medicago truncatula wild-type A17, crystals accumulate in leaves along the secondary veins and the only role attributed to them so far is defense against chewing insects. Calcium oxalate deficient (cod) mutants were isolated in M. truncatula; the cod mutants include cod5, which completely lack crystals in the leaves and cod6 that accumulates fewer and smaller crystals compared to A17. We analyzed gene expression in the cod mutants and A17 using GeneChip® Medicago Genome Arrays and found important differences in transcriptome between the three genotypes. In particular, we found a gene …

Biogeography And Microhabitat Distribution Of Myxomycetes In High-Elevation Areas Of The Neotropics, Carlos Alonso Rojas-Alvarado

Graduate Theses and Dissertations

Myxomycetes are a group of amoeboid organisms with the capacity of forming fruiting bodies that resemble some macrofungi. The ecology and global distribution of species within the group have been studied only during the last half century. For this reason, a number of questions regarding the nature of the interactions that exist between myxomycetes and their environment still lack the empirical evidence required to obtain complete answers. In the Neotropical region, species assemblages have been moderately well studied, but their biogeography and macroecology have received little attention. In high-elevation areas of this region, the situation is especially precarious, due the …