Tat1-72, is an intrinsically disordered protein at pH 4.1 as previously indicated by NMR chemical shifts and coupling constants, and confirmed by 15N-relaxation parameters. The presence of SDS elicits a conformational change to α-helicity in Tat1-72. In the presence of the non-ionic DDM detergent and zinc, Tat was found to be soluble at pH 4 when bound to TAR RNA; TAR binding also elicits a conformational shift to α-helicity in Tat1-72. The β-sheet content of Tat1-72 is increased in the presence of NaCl. In similar conditions, Tat1-72 aggregates stained with Congo Red displayed a yellow-green birefringence and a red-shift in the Congo Red absorbance that is typical of β-amyloid fibril. The web-based algorithm “WALTZ” identifies the majority of the Tat1-72 hydrophobic core region as amyloidogenic. The helical propensity of Tat1-72 in TFE was determined by two-dimensional NMR spectroscopy.

The outcome of leishmaniasis has been shown to be both host genotype and parasite strain dependent. Understanding the role of host and parasite molecules in disease outcome will provide important information for the development of new drugs, new therapies and new vaccines against this disease. In this study, we investigated the role of a host molecule, Phosphatidylinositol 3-kinases (PI3Ks) and a parasite molecule, phosphoglycans in primary and secondary immune response against Leishmania major. We hypothesized that these host and pathogen factors coordinately influence the quality and magnitude of primary and secondary (memory) immune responses (and immunity) against Leishmania major. In the first part of my study, my results show that in the absence of phosphoglycan, antigen-presenting cells (APCs) are able to present parasite antigens to T cells more efficiently and promote a Th1 type of immune responses. However, as phosphoglycan containing molecules are important for parasite survival and virulence, the initial T cell clonal burst is impaired in lpg2-infected mice. This in turn leads to significantly impaired antigen-specific recall responses (measured by proliferation, IFN-g production and delayed-type hypersensitivity response) both in vitro and in vivo. Interestingly, despite this impairment, lpg2- L. major-infected mice were protected against secondary virulent L. major challenge similar to those that healed from WT L. major infections. In the second part of my study, I demonstrate that PI3K deficient mice are highly resistant to primary L. major infection despite impaired T cells response (proliferation and effector cytokines production). Interestingly, this enhanced resistance was not due to enhanced innate immunity or humoral immunity, but was related to reduced regulatory T cell expansion and differentiation. Surprisingly, results from healed PI3Ks deficient mice suggest that an excellent primary resistance to L. major infection does not automatically translate to secondary protective responses because healed p110 KI mice failed to efficiently control secondary L. major challenge infection. We showed that the impaired memory response was due to defective proliferation of Leishmania-specific memory T cells and the inability of central memory T cells to convert to effector memory T cells, which negatively impact on the ability of memory T cells to exit peripheral lymphoid organs and home to the cutaneous site of infection to mediate effector functions. These findings have significant impacts on our knowledge in understanding of host/pathogen interaction and will shed light on future developments of vaccine, vaccination strategy and new drugs.

In this thesis, a new method has been proposed for calculating the frequencydependent parameters of underground cables. The method uses full wave formulation for calculating the modal electromagnetic fields and corresponding voltages and currents and then extracting frequency-dependent per unit length parameters of underground cables. The proposed method can be used for any cross-sectional shape of cables.

A number of natural factors favor the production of sheep in Manitoba. Large tracts of cheap land, unsuited for more intensive types of agricultural endeavor, appear ideal for sheep-raising. These areas provide sufficient forage for large flocks of sheep that can be kept over winter at low cost. The usual practice is to provide low-cost, open-type sheds for shelter, as sheep do very well in such quarters. This type of shelter also requires little in the way of labor that would be necessary in a more elaborate system of housing. The prices of sheep and sheep products in recent years have been consistently higher than previously, and in view of the smaller amount of labor required for sheep raising than for other types of agriculture, one might reasonably have anticipated a substantial increase in the sheep population during the war. Also favoring an expansion of sheep population is the low provincial incidence or relative absence of bacterial, virus and protozoan diseases such as anthrax, foot-and-mouth disease, looping ill, scrapie and braxie

Personal attempts to classify the insect concerned in these studies failed to place it under any previously described species. Samples sent to Dr. Morrison at Washington, D. C. were identified as Toumeyella sp. Dr. Morrison stated that he was "unable to match the specimens exactly with any of the named species of the genus which are represented in our collection." The writer found a marked resemblance to the Scotch pine scale, Toumeyella numismaticum P. & McD. It was felt that the Manitoba insect should be included under the above species, but this was not possible on the basis of existing taxonomic keys. The writer was reluctant to create a new species and further confuse the existing literature on the group... In that this paper is primarily concerned with the economic and biological aspect of the Manitoba insect, no attempt has been made toward a systematic revision of the group. For the sake of convenience, however, the name Manitoba Jack Pine Scale, Toumeyella sp. has been applied in this paper, with reservations as to the appropriateness of the name.

The currant fruit fly, Epochra canadensis, Loew attacks red and white currants (Ribes rubrum L.), flowering currant (Ribes aureum, Pursh) and probably black currant (Ribes nigrum L.) in Manitoba, Instances have been reported of injury to black currants but it was impossible to verify these reports. In other parts of America where this insect is found, black currants and also gooseberries are included in the list of host plants. The currant fruit fly is probably the most destructive insect attacking red and white currants in Manitoba. The damage is caused by the females ovipositing in the partially grown currants. The developing maggots cause many of the currants to ripen prematurely and drop from the bushes. Other infested currants may remain on the bushes until the unifested fruit is ripe. Usually, however, there is a heavy drop from the bushes before the uninjured portion of the fruit is ripe. In some instances as much as fifty per cent of the currant crop falls from the bushes due to the injury caused by this insect. If small white maggots are found within the prematurely ripening currants one may be certain of the identity of the insect as no other insect attacks this fruit in a similar manner in Manitoba....

Samples were taken from virgin and cultivated sites in each of three soil associations in the Black earth zone to study the effect of cultivation on available soil nitrogen. The investigations have shown that cultivation affected the organic matter, nitrogen content and nitrogen distribution in one of the soils to such and extent that rate of nitrification was reduced considerably. In the other two soils cultivation caused a smaller loss in organic matter and nitrogen content and even appeared to increase nitrification of the remaining nitrogen fraction. Field trials were conducted with ammonium sulphate and ammonium nitrate fertilizers on barley, wheat and oats. In some cases the ammonium sulphate and ammonium nitrate was supplemented with ammonium phosphate fertilizer. Significant yield increases were obtained with ammonium sulphate fertilizer. When applied in the fall, ammonium sulphate was more effective that ammonium nitrate as a nitrogen carrier.

One of the outstanding phenomena of the twentieth century, particularly from the point of view of those concerned with welfare, is a growing awareness of the needs and problems of the senior population, those over sixty-five years of age. As this population increases in volume, problems relating to employment, health, housing and recreation can increase in direct proportion, and are receiving a great deal of attention as a result of the concern of government officials, both elected and employed, medical practioners, professional social workers, and volunteers. Following a summary of the present situation and its causes and effects with reference to the social and emotional needs of the aged, it is the intention of this thesis to study and evaluate leisure-time services available to the senior population in the Winnipeg area. A report will be made on a questionnaire survey sent ot a group of churches in Winnipeg as well as on clubs providing leisure-time services for the aged. There will also be an account of a model project undertaken in a neighborhood house, with special emphasis on the role of volunteers and a comparative study of the difference in focus and service when no professional guidance is given and when professionally trained and supervised personnel is provided. It is hoped that an account of study and an evaluation of experience in this field will result in a contribution toward an understanding of some of the factors involved in provision of organized recreation services for senior citizens.

The purpose of this thesis was to conduct a survey and offer a general picture of the housing conditions in the City of Winnipeg. While much effort is required now in preserving housing features and also in improving living conditions, there is an even greater need for planning for the future. Certain steps have been taken towards investigating "Blight" areas in the City but much more remains to be done to prevent future deterioration. It is hoped that this report will serve towards a better undertanding of the nature and scope of the problem of housing which is certainly one of the most important problems faced by the City.

A layered series of granitic, sedimentary and altered volcanic rocks occurs in the Lily Pond Area of Southeastern Manitoba. The sedimentary and volcanic rocks are bands or sheets conformably enclosed within and between quartz diorite, granodiorites and quartz monzonite bands or sheets which are structurally concordant to a central domed quartz diorite mass. Field work and a petrographic study of specimens of the rocks showed that the granitic rocks could be instrusive crystallization differentiation fractions from a common parent basaltic melt. The liquid fractions were emplaced as upward and westward moving sheets which intruded a volcanic-sedimentary complex and left parts of this complex as remnant bands within the instrusive series.