A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg in fulfilment of the requirements for the degree of Master of Science (Haematology) / The region Ilpl3-pl5 on the short arm of chromosome 11 (lip) has been implicated in the initiation or progression of several human malignancies including the embryonic rhabdomyosarcoma Wilms' tumour, bladder, renal cell and ovarian carcinoma. In this study, Fluorescence In Situ hybridisation (FISH) was used to identify the nature of a chromosome llp+ abnormality present in two ovarian carcinoma cell lines after conventional cytogenetic techniques had failed to elucidate the chromosomal origin of the abnormality. Using whole chromosome library probes, the abnormality in cell line UW0V2 was found to be composed entirely of chromosome 3 material representing the translocation t (3;11) (pl2-14;pl5). In the protein-free subline UW0V2(Sf), the abnormality was found to consist of the complex translocation t (3;8; 11) (pl2-14 ;q22-24;pl5) . It is possible that the involvement of chromosome 8 in this translocation was a cell culture phenomenon. Other structural and numerical abnormalities elucidated with FISH in cell line UW0V2(Sf) included lq+, +5, +7, 7q-, 8q+, +12, +14, 14q+, -15, 16q- and -18. Using FISH together with the gene probe pSB|5 and the CEPH YAC probes 892g9, 785e5, 847al2, 954f4, 966e8 and 845a3, the breakpoint region on chromosome 11 in the _ two cell lines was narrowed down and mapped to the region Ilpl4.3-pl5.1 lying between probes 966e8 (D11S902) and 845a3 (D11S899). This represents a physical distance of approximately 1 Mb. The breakpoint in the two cell lines appeared to involve the same region on llplS.l. In a separate study, three epithelial ovarian tumour specimens and four ascitic fluid specimens were obtained. Tumour specimens T2 and T4 and ascitic fluid specimens AF-1, AF-2 and AF-3 were all cytogenetically uninformative. Cytogenetic analysis of specimen T5 revealed a single clonal abnormality involving a deletion in the region 6q21. Ascitic fluid specimen AF-5 yielded cytogenetically normal metaphases. Both specimens were hypodiploid and revealed a cytogenetically normal chromosome 11. Using FISH and CEPH YAC probes 966e8 and 845a3, no abnormalities were detected in the region llpl4.3-pl5.1 in these two specimens but one cannot rule out the possibility of submicroscopic abnormalities lying within the region between these probes. From this study we speculate that chromosome 6 abnormalities may be important in the initiation of these tumours. From the results obtained with cell lines UW0V2 and UW0V2 (Sf) we speculate that the chromosome 3 abnormalities were an early event in the evolution of these tumours while the chromosome 11 abnormality was a later event. Little is known about the region llpl4.3-pl5.1 and very few disease loci have been assigned to this region, however, we may speculate that this region harbours a tumour suppressor gene or an oncogene whose disruption or activation is critical to the pathophysiology of ovarian carcinoma and other genitourinary cancers. / WHSLYP2017

There are three human pathogenic species of the genus Yersiniae: Yersinia pestis, Yersinia enterocolitica, and Yersinia pseudotuberculosis. To cause disease, these strains inhibit several key innate defense mechanisms, including phagocytosis, the critical process for bacterial clearance. The ability of Yersinia to evade the immune defense is dependent on delivery of virulence effectors, Yersinia outer proteins (Yops), into the interacting cell by a mechanism involving the type III secretion machinery. We have shown that the virulence protein YopK plays an important role in the control of Yop effector translocation via a feedback mechanism involving another virulence protein, YopE. We also found that YopK participated in regulation of Yop effector translocation by modulating level and ratio of the pore-forming proteins YopB and YopD in the target cell membrane. Further, using a yeast two-hybrid screen with YopK as a bait, the eukaryotic protein RACK1 was identified as a target for this virulence protein. We found that RACK1 was engaged upon Y. pseudotuberculosis-mediated β1-integrin activation, where it was recruited to phagocytic cups. Downregulation of RACK1 by RNAi resulted in a reduced ability of Y. pseudotuberculosis to block phagocytosis, indicating that RACK1 is required for efficient Yersinia-mediated antiphagocytosis. Based on our data, we suggest a model where Yersinia, via YopK, targets RACK1 to ensure a directed delivery of the Yop effectors to the “right place” where they bind to and inactivate their targets, resulting in efficient inhibition of phagocytosis.   A yopK mutant strain over-delivers Yop effectors, but is still avirulent in mice, indicating that YopK is important for the fine-tuning of effector protein delivery during infection. To analyse this, we investigated the importance of YopK during in vivo infection. We found that a yopK mutant colonized Peyer’s patches and the mesenteric lymph node more rapidly compared to wild-type Y. pseudotuberculosis, but was unable to spread systemically to liver and spleen and cause full disease in mice. Further, we showed that a yopK mutant was able to colonize liver and spleen and cause full disease in mice lacking the main phagocytes, polymorphonuclear leukocytes (PMNs). We also showed that YopK was important for Yersinia-mediated silencing of the PMN response. To summarize, we suggest that YopK is important for Yersinia to evade the PMN defense and thereby spread systemically and cause disease. YopK is proposed to do this by allowing a controlled, directed Yop effector delivery that is just sufficient to inhibit host immune defense mechanisms. The controlled and precise delivery of virulence effectors avoids inappropriate triggering of PMNs and thereby an enhanced immune response favoring the host.

The translocation of Escherichia coli O157:H7 as well as the impact of water washing and partial or complete surface trimming as possible pathogen reduction strategies were evaluated for vacuum-packaged beef subprimals destined for non-intact use. Cap-on and cap-off beef top sirloin butts were inoculated with two levels of E. coli O157:H7! a high-inoculum at approximately 10^4 CFU/cm^2 and a low-inoculum at approximately 10^2 CFU/cm^2. Following inoculation, the subprimals were vacuum packaged and stored for either 0, 14, or 28 days. Upon opening, the following sites were evaluated: exterior of the bag, purge, the inoculation site on the subprimal, the area adjacent to the inoculation site, and the surface opposite from the inoculation site. The following treatments then were applied: water wash, water wash followed by full-surface trimming, water wash followed by partial-surface trimming, full-surface trimming, full-surface trimming followed by water wash, partial-surface trimming, and partial-surface trimming followed by water wash. For both high and low inoculated top sirloin butts, contamination of adjacent and opposite surfaces was found after vacuum packaging. Of the treatments applied, water washing alone and partial-surface trimming were the least effective for both high and low inoculated subprimals. Full trimming, with or without a water wash, proved to be the most effective treatment used to reduce E. coli O157:H7 to non-detectable levels.

Urban development and habitat fragmentation threaten recovery and management of the endangered Florida Key deer (Odocoileus virginianus clavium). Urban development has reduced deer dispersal from their core habitat resulting in deer “overabundance” and has increased deer-human interactions (mostly deer-vehicle collisions [DVCs]). Conversely, deer populations on outer islands have declined in recent years due to limited deer dispersal from source populations. In order to expand the Key deer’s range and reduce DVCs within their core habitat, wildlife managers determined translocations and DVC mitigation were needed. Thus, the objectives of my thesis were to determine (1) effects of translocation on the establishment of outer-island local populations, and (2) effects of United States 1 Highway (US 1) improvements (i.e., exclusion fencing, underpasses, deer guards, and extra lane creation) on DVCs and deer movements. I evaluated the efficacy of translocations by comparing annual survival and seasonal ranges between resident and translocated deer and by analyzing reproduction of translocated deer. Translocated females (yearlings and adults) had lower annual survival than resident deer. Conversely, males (yearlings and adults) demonstrated higher annual survival than resident males. Due to low sample sizes and large variation, these numbers are potentially less important than the high overall survival (only 4 of 38 died). Seasonal ranges were generally smaller for resident deer than translocated deer. I attribute differences in ranges to differences in habitat quality between the core habitat and destination islands and to use of soft releases. Presence of fawns and yearlings indicated successful reproduction of translocated deer. Overall, the project was successful in establishing populations on the destination islands. The US 1 Highway improvements reduced DVCs along the fenced section of US 1 (2003, n = 2; 2004, n = 1; 2005, n = 0); however, overall DVCs increased on Big Pine Key (1996–2000, x¯ = 79; 2003, n = 91; 2004, n = 84; 2005, n = 100). Data suggest DVCs shifted to the unfenced segment of US 1. However, monthly deer surveys also suggested an increase in deer numbers that may explain overall DVC increases observed in my study.

Thèse doctorat : Médecine. Virologie : Université de Nantes : 2005. / Bibliogr. 146-173 f.

Thèse de doctorat : Sciences de la vie et de la santé : Paris 12 : 2005. / Version électronique uniquement consultable au sein de l'Université Paris 12 (Intranet). Titre provenant de la version imprimée. Pagination : 110 f. Bibliogr. : 134 réf.

Thèse d'exercice : Médecine. Anatomie et cytologie pathologiques : Nantes : 2008. / Bibliogr.

Thesis (Ph. D.)--University of Chicago, Dept. of Pathaology, 2002. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Chemistry." Includes bibliographical references (p. 131-144).

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