A 6 DoF navigation algorithm for autonomous underwater vehicles

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6-DoF Navigation Systems for Autonomous Underwater Vehicles

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The relative involvement of Th1 and Th2 associated immune responses in the expulsion of a primary infection of Heligmosomoides polygyrus in mice of differing response phenotype

T helper cell (Th1 and Th2) associated responses were examined following a primary infection with the gastrointestinal nematode Heligmosomoides polygyrus in five inbred strains of mice with different resistance phenotypes. Levels of (i) mast cell protease, (ii) specific IgE, (iii) nitric oxide and (iv) specific IgG2a, as markers of Th2 and Th1 associated responses, respectively, were determined in sera and intestinal fluids and correlated with worm burdens. The ‘fast’ responder (resistant) strains SWR and SJL produced strong Th2 and Th1 associated responses respectively in a mutually exclusive fashion. The F1 hybrid(SWR £ SJL) F1, showed rapid expulsion of the parasite and expressed both intense Th1 and Th2 responses, suggesting synergism between Th1 and Th2 activity in these mice. The results indicate that both Th2 and Th1 responses operate in mice following a primary infection with H. polygyrus and that each Th response may be involved to a greater or lesser degree within certain strains. Resistance to H. polygyrus was found to correlate only to the intensity of either the gut-associated mastocytosis or nitric oxide production in these strains but not to either specific IgE or IgG2a titres. Chronic infections in the ‘slow’ response phenotype mouse strains CBA and C57BL/10, were associated with both poor Th2 and poor Th1-associated responses attributed to a general parasite-mediated immunosuppression of the host immune response to infection

Probing a Promiscuous Binding Pocket of the Proteasome

The proteasome is a multi-catalytic protease complex responsible for the degradation of unneeded, damaged or misfolded proteins. The proteasome is a validated target for the treatment of haematological malignancies such as multiple myeloma and mantle cell lymphoma, as demonstrated by the FDA approved proteasome inhibitors bortezomib, carfilzomib and ixazomib. These inhibitors, especially bortezomib, suffer from poor specificity and relatively high prevalence of resistance, therefore new inhibitors should be designed such that these characteristics improve. This thesis details probing of the relatively unexplored primed site binding channel of the β5 subunit of the proteasome with P2 extended proteasome inhibitors. This work indicates the primed site binding channel as a promiscuous target for interaction which may aid in increasing the specificity of proteasome inhibitors Chapter 1 introduces the structure and activity of the proteasome and its implications and relevance to human diseases. Inhibition of the proteasome by small molecule inhibitors is discussed, including the main classes, exemplary inhibitors, their mechanisms and applications. The primed site binding channel is then identified via examination of the crystal structure of the proteasome as a pocket which provides potential for new inhibitor-enzyme interactions. Chapter 2 details the design, synthesis and evaluation of inhibitors 2.01-2.04 which probe the extent of the promiscuity of the primed site binding channel. The collection of published inhibitors which are known to, or are likely to, occupy the primed binding sites demonstrate the primed site binding channel as promiscuous regarding the substituents it accepts. The P2 residue of bortezomib was identified as providing an access point to the primed binding sites. Imidazolyl and phenyl substituents were demonstrated to be accommodated by the primed site binding channel, with greater potency found for longer extensions into the pocket, or inhibitors with a phenyl substituent within the pocket. Chapter 3 describes further probing of the primed site binding channel with the azobenzene-containing proteasome inhibitor 3.01, which can be converted between cis- and trans-enriched isomeric states using light. The azobenzene substituent was placed at the P2 position of a bortezomib-inspired inhibitor and allowed probing of the primed binding sites with greater conformation predictability. Remarkably, despite significant change in conformation between the cis and trans isomers, there is little difference between the low nanomolar range potencies of the isomeric states. This further indicates the significant promiscuity of the primed site binding channel. Chapter 4 presents the evaluation of inhibitors 2.01-2.04 and the thermally adapted state of 3.01 alongside bortezomib against bovine α-chymotrypsin to examine the specificity of such inhibitors. Primed site-occupying inhibitors 2.01 and 2.04 demonstrate more than 2.5 times greater specificity towards the β5 subunit of the proteasome over α-chymotrypsin. This result indicates occupying the primed site binding channel as an effective strategy of improving proteasome inhibitor specificity, which may be critical in improving upon the currently available proteasomeThesis (MPhil) -- University of Adelaide, School of Physical Sciences, 202

Interleukin (IL)–12 and IL-23 Are Key Cytokines for Immunity against Salmonella in Humans

Patients with inherited deficiency of the interleukin (IL)–12/IL-23–interferon (IFN)–g axis show increased susceptibility to invasive disease caused by the intramacrophage pathogens salmonellae and mycobacteria. We analyzed data on 154 patients with such deficiency. Significantly more patients with IL-12/IL-23–component deficiency had a history of salmonella disease than did those with IFN-g–component deficiency. Salmonella disease was typically severe, extraintestinal, and caused by nontyphoidal serovars. These findings strongly suggest that IL-12/IL-23 is a key cytokine for immunity against salmonella in humans and that IL-12/IL-23 mediates this protective effect partly through IFN-g–independent pathways. Investigation of the IL-12/IL-23–IFN-g axis should be considered in patients with invasive salmonella disease

Direct cell-to-cell spread of a pathogenic yeast.

BACKGROUND: Cryptococcosis, a fatal fungal infection of the central nervous system, is one of the major killers of AIDS patients and other immunocompromised hosts. The causative agent, Cryptococcus neoformans, has a remarkable ability to 'hide' and proliferate within phagocytic cells of the human immune system. This intracellular phase is thought to underlie the ability of the pathogen to remain latent for long periods of time within infected individuals. RESULTS: We now report that Cryptococcus is able to undergo 'lateral transfer' between phagocytes, moving directly from infected to uninfected macrophages. This novel process was observed in both C. neoformans serotypes (A and D) and occurs in both immortalised cell lines and in primary human macrophages. Lateral transfer is independent of the initial route of uptake, since both serum-opsonised and antibody-opsonised C. neoformans are able to undergo direct cell-to-cell transfer. CONCLUSION: We provide the first evidence for lateral transfer of a human fungal pathogen. This rare event may occur repeatedly during latent cryptococcal infections, thereby allowing the pathogen to remain concealed from the immune system and protecting it from exposure to antifungal agents

Identification of distinct human invariant natural killer T-cell response phenotypes to alpha-galactosylceramide.

Background Human CD1d-restricted, invariant natural killer T cells (iNKT) are a unique class of T lymphocytes that recognise glycolipid antigens such as α-galactosylceramide (αGalCer) and upon T cell receptor (TCR) activation produce both Th1 and Th2 cytokines. iNKT cells expand when cultured in-vitro with αGalCer and interleukin 2 (IL-2) in a CD1d-restricted manner. However, the expansion ratio of human iNKT cells varies between individuals and this has implications for attempts to manipulate this pathway therapeutically. We have studied a panel of twenty five healthy human donors to assess the variability in their in-vitro iNKT cell expansion responses to stimulation with CD1d ligands and investigated some of the factors that may influence this phenomenon. Results Although all donors had comparable numbers of circulating iNKT cells their growth rates in-vitro over 14 days in response to a range of CD1d ligands and IL-2 were highly donor-dependent. Two reproducible donor response patterns of iNKT expansion were seen which we have called 'strong' or 'poor' iNKT responders. Donor response phenotype did not correlate with age, gender, frequency of circulating iNKT, or with the CD1d ligand utilised. Addition of exogenous recombinant human interleukin 4 (IL-4) to 'poor' responder donor cultures significantly increased their iNKT proliferative capacity, but not to levels equivalent to that of 'strong' responder donors. However in 'strong' responder donors, addition of IL-4 to their cultures did not significantly alter the frequency of iNKT cells in the expanded CD3+ population. Conclusion (i) in-vitro expansion of human iNKT cells in response to CD1d ligand activation is highly donor variable, (ii) two reproducible patterns of donor iNKT expansion were observed, which could be classified into 'strong' and 'poor' responder phenotypes, (iii) donor iNKT response phenotypes did not correlate with age, gender, frequency of circulating iNKT cells, or with the CD1d ligand utilised, (iv) addition of IL-4 to 'poor' but not 'strong' responder donor cultures significantly increased their in-vitro iNKT cell expansion to αGalCer