Thesis (Ph.D)--Biology, Georgia Institute of Technology, 2010. / Committee Chair: Patricia Sobecky; Committee Member: Eric Stabb; Committee Member: Jim Spain; Committee Member: Roger Wartell; Committee Member: Thomas DiChristina. Part of the SMARTech Electronic Thesis and Dissertation Collection.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

The conditions by which the production, in liquid media, of hemolytic activity by growing cells of T. hyodysenteriae and T. innocens are described. / From a ribonucleic acid added culture broth of T. hyodysenteriae, two hemolysins are shown in the supernatant. For each of them, a purification scheme allowing the obtention of an homogeneous hemolytic preparation by gel filtration and electrophoresis, is proposed. One hemolysin is associated with ribonucleic acid (HN) while the later is associated with bovine serum albumin (HP). They share some properties: their synthesis is blocked by chloramphenicol, they do not have proteolytic or phospholipasic activities, they are insensitive to oxygen and their activity does not require bivalent cations or is sensitive to EDTA's action; they are lytic to all red blood cell's type tested. They differ by the size of their apparent molecular weight, their mode of action, the stability of their activity to temperature and different pH and, their pattern of sensitivity to proteolytic enzymes. / The isolation of a non-hemolytic mutant strain of T. hyodysenteriae and its use in a ligated ileal loop model in rabbit has shown that there is a relation between the loss of the hemolytic activity and the loss of the enterotoxic activity.

Pseudomonas aeruginosa is an opportunistic human pathogen which, like many other Gram negative pathogens, employs quorum sensing - regulated virulence factors to establish an infection in its host. Quorum sensing in P. aeruginosa populations is controlled by low molecular weight (hapten) signalling molecules known as homoserine lactones (HSLs). Blocking bacterial communication using antibodies is an attractive strategy for infection control as QS takes a central role in P. aeruginosa infections, and antibodies can recognise their targets with exquisite specificity. There are two well-studied QS circuits in P. aeruginosa- the Las system and the Rhl system, controlled by two autoinducers compounds, 3-oxo-C12-HSL and C4-HSL respectively. Antibodies raised against HSL compounds can reduce the expression of virulence factors controlled by QS circuit and the immunomodulatory effects of 3- oxo-C12-HSL. In order to generate antibodies with high sensitivities against the autoinducer compounds of P. aeruginosa, a panel of HSL compounds was synthesised, conjugated to the carrier protein and used for sheep immunisation. High specificity anti-HSL antibodies were isolated from an immunised sheep antibody repertoire using phage display technology. These phage antibody hits were converted into single chain antibody (scAb) format, which possessed a HuCκ gene for detection and 6x histidine tag for purification. Soluble scAbs expressed in E. coli were purified and characterised using ELISA. Unique clones showing high sensitivity for free HSL compounds were reformatted into sheep-mouse chimeric IgGs, expressed transiently in COS 7 cells and characterised using biochemical assays. These cross-reactive monoclonal antibodies were shown to recognise HSL compounds in low nanomolar concentrations and have the potential to reduce virulence gene expression in P. aeruginosa.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1979. / Bibliography: leaves 147-156. / Microfiche. / x, 156 leaves ill. (some col.) 29 cm

Thesis (Ph.D.)--McMaster University, 2006. / Supervisor: E.D. Brown. Includes bibliographical references (leaves 95-104).

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 216-235). Also available on the Internet.

Thesis (M.S.)--University of Michigan, 1991.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 187-191). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 216-235). Also available on the Internet.