Thesis (MSc. (Veterinary Tropical Diseases)--University of Pretoria, 2007. / Includes bibliographical references.

Thesis (MSc (Veterinary Sciences))--University of Pretoria, 2002. / Includes bibliographical references.

Thesis (MSc (Veterinary Tropical Diseases, Veterinary Science))--University of Pretoria, 2009. / Includes bibliographical references. Also available in print format.

No description available.

Thesis--University of Florida. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 144-155).

Made available in DSpace on 2014-06-11T19:22:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-02-20Bitstream added on 2014-06-13T20:49:41Z : No. of bitstreams: 1 oliveira_pr_me_rcla.pdf: 1932161 bytes, checksum: f820087f383a5435368c32d73091195c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente estudo apresenta a análise morfológica, histológica e ultraestrutural do ovário bem como a dinâmica da vitelogênese de fêmeas de carrapatos Amblyomma triste. O ovário dessa espécie é do tipo panoístico, não possuindo, portanto, células nutridoras nem foliculares. O ovário é composto por ovócitos que estão presos à parede do ovário, camada única de células epiteliais, através do pedicelo, estrutura celular com função de sintetizar e fornecer substâncias para o desenvolvimento dos mesmos. Os ovócitos foram identificados e classificados em quatro estágios diferentes de desenvolvimento. A classificação foi realizada baseada na presença de quatro características morfológicas: aspecto citoplasmático; localização da vesícula germinal; presença, quantidade e constituição dos grânulos de vitelo e presença de cório. Nos ovócitos de A. triste ocorre a síntese endógena e principalmente exógena dos elementos do vitelo. Em carrapatos A. triste, os lipídios dos ovócitos têm origem: a) exógena, em todos os estágios, uma vez que os elementos são captados da hemolinfa via superfície do ovócito e/ou provenientes das células do pedicelo e, b) endógena, que ocorre somente nos ovócitos III e IV. As proteínas do vitelo dos ovócitos de A. triste têm origem: a) exógena, nos ovócitos II, III e IV, via células do pedicelo que atuariam como fornecedoras deste elemento e também por meio da captação da hemolinfa pelo próprio ovócito e, b) endógena, nos ovócitos IV. Já os polissacarídios teriam origem a partir de duas fontes exógenas, a primeira com a produção e/ou transporte desse elemento via células do pedicelo, e a segunda, por meio da captação da hemolinfa via membrana do ovócito. No presente trabalho, a função do pedicelo como fornecedor de elementos para os ovócitos durante a vitelogênese fica estabelecida nessa espécie de carrapatos. / The present study presents the morphological, histological and ultrastructural analysis as well as the dynamics of vitellogenesis in females of the tick Amblyomma triste. The ovary of this species is of the panoistic type, not presenting nurse nor follicular cells. The ovary is composed of oocytes which remain attached to wall of the ovary (single layer of epithelial cells) through the pedicel, a cellular structure responsible for synthesizing and providing substances to oocytes, promoting their development. The oocytes had been identified and classified into four different developmental stages. The classification was carried out based on the presence of four morphologic characteristics: cytoplasm appearance; site of the germ vesicle; presence, quantity and constitution of the yolk granules and presence of chorium. In the oocytes of A. triste occur the endogenous synthesis and mainly exogenous incorporation of yolk elements. The lipids have two different origin: a) exogenous, in all the oocytes, captured from the hemolymph through the oocyte surface and produced by pedicel cells and b) endogenous, only stages III and IV. The proteins have origin: a) exogenous, in the oocytes II, III e IV, where the pedicel cells contribute with the protein supply for the yolk constitution and also through the capture of this element from the hemolymph by the oocyte and, b) endogenous, in the oocytes IV. The polysaccharides would have two exogenous sources: the production and transportation of this element through the pedicel cells; and the capture of the hemolymph through the oocyte plasmic membrane. The present study determines the role of the pedicel as a provider of yolk elements to these tick species oocytes.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1965. / Abstracted in Dissertation abstracts, v. 25 (1965) no. 10, p. 5533. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph.D.)--Flinders University, School of Biological Sciences. / Typescript bound. Includes bibliographical references: (leaves 135-157) Also available online.

Four commonly occurring genera of ticks in South Africa were tested for their capacity to acquire and transmit Borrelia burgdoiferi, the causative agent of Lyme disease. Attempts were made to infect rabbits with a culture of B. burgdoiferi, and tick transmission experiments were carried out using the rabbits as the host of infection. Only one rabbit was successfully infected. Histological changes associated with a B. burgdoiferi infection were noted in this rabbit, but no spirochaetes were isolated. All other host animals failed to become infected with the B. burgdoiferi. As a consequence transmission experiments with the local ticks failed. Serological surveys conducted on rodents, horses and cattle using immunofluorescent and haemagglutination tests indicated that there is evidence that Borrelia species occur widely and that there is a possibility of B. burgdoiferi occurring in South Africa. Studies conducted on ticks from suspected endemic areas revealed the presence, in Ixodes bakeri only, of a spirochaete-like organism that reacted with monoclonal antibody H5332. Shortcomings of the study are highlighted and proposals are presented to address the problem of identifying specific B. burgdoiferi infections.

No description available.