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No description available.

Human intestinal microbiomes exhibit a large degree of interindividual compositional variation. Animal models, such as the zebrafish, facilitate the design of controlled and highly replicated studies that allow us to understand the normal variation in vertebrate intestinal composition and to study the rules guiding normal assembly of these complex communities. The smaller intestinal size and high fecundity of the zebrafish allow us to fully sample the intestinal contents of many animals, while the optical transparency allows direct in vivo observation of fluorescently labeled bacterial species within the intestine. The studies in this dissertation utilize these advantages to investigate the composition, colonization dynamics and functional requirements for colonization in the vertebrate intestine. We first describe the taxonomic composition and diversity of the zebrafish intestinal microbiota from wild-caught and domesticated zebrafish. In the process, we identify a set of core bacterial genera that are consistently present in zebrafish intestines. We then use species from two of these genera in subsequent studies to gain a detailed understanding of the colonization dynamics and genetic requirements of the two species. We initially describe the application of light sheet microscopy to imaging the zebrafish intestine and associated colonizing bacteria. We find that a single species, Aeromonas veronii, does not occupy the entire intestinal space and that competition within the same species appears to prevent further colonization. These results are extended to a zebrafish isolated Vibrio species as well as A. veronii by tagging bacteria with transposon insertions and tracking the changes in colonizing population sizes. These insertion libraries also identify genes in each bacterial species that are important in the process of colonization, highlighting the key role for motility and chemotaxis in this process. The descriptions and methods discussed in this dissertation advance the use of this important model organism towards the understanding of vertebrate host-microbial interactions. This dissertation includes previously published co-authored material as well as unpublished co-authored material. / 10000-01-01

Digitized by Kansas Correctional Industries

Porcine reproductive and respiratory syndrome virus (PRRSV) is a rapidly evolving virus that has significant economic and welfare implications for the pig industry. Vaccination strategies have proved largely ineffective in controlling PRRSV, in some cases even reverting to virulence. An increasing body of evidence suggests a host genetic basis for PRRSV resistance so there is a need to examine the role of host genetics in a biologically relevant in vitro cell culture system. However, PRRSV research is inhibited by the current scarcity of suitable in vitro culture systems. With the aim of developing a convenient in vitro model, porcine bone marrow-derived macrophages (BMDM) were evaluated as a PRRSV cell culture system. BMDM were found to be highly permissive to Type I PRRSV and amenable to genetic manipulation. BMDM proved to be excellent cells for virus production, producing significantly higher titres of PRRSV than commonly used alternative cell types. Surprisingly, PRRSV entry into BMDM was found to be independent of both the prototypic PRRSV receptors, CD163 and CD169, providing further evidence for the existence of alternate PRRSV entry mechanisms in primary cell types. To explore the genetics of pig susceptibility to PRRSV, network-based analysis of host transcriptional datasets, following PRRSV challenge, revealed important differences in co-regulated gene pathways between samples from pigs with different PRRSV-permissiveness. These pathways included genes with important, recently characterised, anti-pathogen activities. The incorporation of network-based transcriptional analysis and published genetic variation data led to the identification of a member of the guanlyate binding protein family, GBP-1, as a candidate host gene involved in controlling PRRSV replication. Overexpression of GBP-1 in BMDM revealed a significant anti-PRRSV function for this protein. Further investigation of published genetic variation in GBP-1 suggested a potential role of this gene in PRRSV tolerance. The results presented in this thesis provide evidence for an alternate PRRSV entry pathway in a biologically relevant cell type. The discovery of a highly PRRSV-infectable cell type with potential for genetic manipulation adds a useful new tool to the area of PRRSV research. The identification of GBP-1 as a novel anti-viral protein with a significant inhibitory effect on PRRSV infection, together with genetic variation in this gene, prompts further research into the genetic basis for PRRSV resistance.

acase@tulane.edu / In an effort to construct and study aqueous supramolecular assemblies that mimick those of nature (proteins and viral capsids), a novel, water-soluble deep-cavity cavitand has been synthesized – tetra-exo-methyl octa-acid (TEXMOA). In addition, water-soluble cavitand tetra-exo-carboxy tetra-acid (TECTA) was synthesized as an anti-dimerization host to further explore the binding properties of a monomeric host-guest system. The synthetic processes are investigated and discussed in this dissertation. Driven by hydrophobic effect, long-chain alkane guests bind strongly to the pocket of TEMOA in aqueous media. Initial NMR studies suggest that the steric hindrance induced from the exo-methyl groups of TEXMOA is responsible for a non-monotonic assembly profile toward the guests (from monomeric to dimeric and mixture of both in some cases). The synthesis of TECTA required direct ortho metalation and careful purification steps. However, the host still displayed the binding properties as intended, since the carboxylate groups of TECTA in the exo position prevented capsule formation with various aliphatic guests in water. Based on previous findings, modified 1-adamantanoic acids were expected to be potential strong-binding guests for these hosts. Therefore, chloro-, bromo, and iodo-substituted adamantanoic acids were synthesized in order to expand the library of guest molecules. The Z-isomer of these halogenated adamantanoic acids were synthesized from the Z-2-hydroxy-5-adamantanoic acids with the corresponding mineral acids, and these reactions were found to be stereoselective. The amine-footed meta-basket was also synthesized as a potential detection ligand in biosensors via SPR (surface plasmon resonance). The synthesis of the host utilized a modified Staudinger reaction from the azido- precursor. / 1 / Thong Nguyen

1v. (various pagings) : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.Sc.1974) from the Dept. of Entomology, University of Adelaide

"February 2005" / Includes bibliographical references. / 1 v. (various paging) : ill., plates ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / It has recently been shown that a thelytokous laboratory culture of the parasitoid wasp Venturia canescens contains two genetically distinct lines, coexisting on their host, the flour moth Ephestia kuehniella. The primary aim of the research presented in this thesis was to determine the basis of the coexistence of the two wasp strains, and estimate whether it is an artefact of the laboratory rearing conditions, or could, in principle, occur in field populations. / Thesis (Ph.D.)--University of Adelaide, School of Agriculture and Wine, Discipline of Plant and Pest Science, 2005

The Guest Host Mode of LCD is doped the dichroic dyes in liquid crystal and it have anisotropic absorbefacient. This operation mode can produce dark or brightness to achieve display target by the electric field and this can operate in the non-polarizer type to achieve high reflectance. Because of market requirement in the e-paper display, so the reflective LCD by the guest host mode is a focal once again. In this study, we will doped the black dichroic dyes in liquid crystal and than we fill into the homogenous alignment cell by difference rubbing direction and homeotropic alignment cell to investigate the optical-electric characteristic in the non-polarizer and polarizer type, because in the difference alignment condition can influence the behavior of dichroic dyes, and we fabricate the double cell to improve the optical-electric characteristic. The reflective type guest host display still have many research space, like dope the dichroic dye in PDLC(polymer dispread liquid crystals) or cholesteric liquid crystal to achieve flexible and bistable characteristic.

Thesis (Ph. D.)--Oregon State University, 2003. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.