M.Sc. / Please refer to full text to view abstract / Prof. A. Avenant-Oldewage

Please read the abstract in the section front of this document / Thesis (PhD (Zoology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted

Apanteles rubecula is a solitary insect parasite of Pier is rapae (small cabbage white butterfly, imported cabbageworm). The parasite has been successfully introduced to Australia and Vancouver, Canada but has failed to become established at other North American release sites. This practical problem illustrates a fundamental aspect of insect ecology. The seasonal biology of insects is interpreted here as an interaction of responses to ambient conditions. Emphasis centers on the rates at which life history phenomena occur and the importance of the insect's biological chronometers on the outcome of its ecological relationships with its host and its local climate. Comparisons are made between Canberra, Australia and Vancouver, Canada. The parasite's developmental response to temperature is similar in Canberra and Vancouver but the host response differs. Canberra A. rubecula have a longer generation time relative to the host at low temperatures, but shorter generation times at higher, midseason temperatures. Vancouver parasites always have faster generation times than their hosts but the season is truncated in August by a diapause response to daylengths shorter than I5h. The beginning of the season is delayed until late May by the high thermal requirement to terminate diapause. These local responses to temperature and photoperiod result in different phenologies which, while appropriate locally, are disastrous elsewhere. The failure of North American attempts to establish Vancouver A. rubecula is attributed to the diapause characteristics of the released insects. They entered diapause while ambient temperatures remained warm enough for morphogenesis and were unable to survive the obligatory period to diapause termination. Manipulation of the diapause response is one technique in ecological pest management. A methodology for a breeding program and its analysis is presented. Practical suggestion for biological control efforts are made and the role of individual physiological responses in insect seasonal ecology are discussed. / Land and Food Systems, Faculty of / Graduate

The purpose of this study was threefold. The literature concerning parasites of A. crepitans was to be brought up to date. Contributions to the general body of knowledge pertaining to the parasitic fauna of host specimens of A. crepitans and specifically those found in Denton County, Texas, were to be made. Finally, specimens found parasitizing host specimens of A. crepitans were to be preserved and classified.

Orientador: Reinaldo José da Silva / Resumo: Parasitas são organismos fundamentais na ecologia e desempenham papel importante nos ecossistemas e estão incluídos na biodiversidade mundial. No presente trabalho foi descrita a diversidade de helmintos na comunidade de 22 espécies de anuros (Boana raniceps, Chiasmocelis albopunctata, Dendropsophus minutus, Dendropsophus nanus, Dermatonotus muelleri, Elachistocleis bicolor, Leptodactylus chaquensis, Leptodactylus fuscus, Leptodactylus latrans, Leptodactylus mystacinus, Leptodactylus podicipinus, Physalaemus albonotatus, Physalaemus cuvieri, Physalaemus nattereri, Pithecopus azureus, Pseudis platensis, Pseudopaludicola mystacalis, Rhinella diptycha, Scinax fuscomarginatus, Scinax ruber, Scinax similis e Trachycephalus typhonius) provenientes da Reserva Particular do Patrimônio Natural (RPPN) Cisalpina, Brasilândia, Mato Grosso do Sul, Brasil. Foram analisados 794 anuros com um total de 22 espécies hospedeiras pertencentes a seis famílias e a prevalência de anuros parasitados foi de 55,5% (441 indivíduos). Foram recuperados 22.350 helmintos distribuídos em 37 taxa. Este estudo amplia o registro tanto para uma nova localidade quanto para registros de novos hospedeiros (n = 55). Nematoides foram os helmintos que apresentaram maior riqueza (n = 22), seguidos de digenéticos (n = 11), cestoides (n = 2), acantocéfalos e monogenéticos (n =1). A comunidade de helmintos foi composta em sua maioria por espécies generalistas (Aplectana membranosa, Cosmocerca parva, Catadiscus marinholutz... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Parasites are fundamental organisms in ecology and play an important role in ecosystems and are included in the world biodiversity. The present study describes the diversity of helminth community of 22 anuran species (Boana raniceps, Chiasmocelis albopunctata, Dendropsophus minutus, Dendorpsophus nanus, Dermatonotus muelleri, Elachistocleis bicolor, Leptodactylus chaquensis, Leptodactylus fuscus, Leptodactylus latrans, Leptodactylus mystacinus, Leptodactylus podicipinus, Physalaemus albonotatus, Physalaemus cuvieri, Physalaemus nattereri, Pithecopus azureus, Pseudis platensis, Pseudopaludicola mystacalis, Rhinella diptycha, Scinax fuscomarginatus, Scinax ruber, Scinax similis e Trachycephalus typhonius) from Reserva Particular do Patrimônio Natural (RPPN) Cisalpina, Brasilândia, Mato Grosso do Sul, Brazil. In total, 794 anurans were analyzed with a total of 22 host species belonging to six families and the prevalence of parasitized anurans was 55.5% (441 individuals). We recovered 22,350 helminths distributed in 37 taxa. This study expands the record for both a new location and for new host records (n = 55). Nematodes were the helminths that showed the highest richness (n = 22), followed by digenetics (n = 11), cestodes (n = 2), acanthocephalans and monogenenean (n = 1). The helminth community was mostly composed of generalist species (Aplectana membranosa, Cosmocerca parva, Catadiscus marinholutzi, Catadiscus propinquus). Many larval forms have been found such as Physalopter... (Complete abstract click electronic access below) / Doutor

Orientador: Luciano Alves dos Anjos / Coorientador: Reinaldo José da Silva / Resumo: A referida tese é o resultado de um trabalho que buscou discutir, como tema geral, o impacto que os parasitas podem causar na ecologia de seus hospedeiros. Ela foi divida em dois capítulos: o primeiro capítulo é uma revisão bibliográfica que discute sobre como os parasitas podem influenciar no desempenho reprodutivo de seus hospedeiros; e o segundo capítulo investigou em três espécies de anfíbios anuros (Leptodactylus chaquensis, Leptodactylus podicipinus, e Hypsiboas raniceps), se os indivíduos parasitados por helmintos são acometidos por alterações em aspectos da reprodução. As três espécies de anuros estudadas, não apresentaram evidências que possam ter alguma relação entre a intensidade parasitária de helmintos e caracteres morfológicos associados à reprodução. O que sugere que estas espécies estudadas apresentem respostas imunológicas e/ou adaptações fisiológicas mediante infecção parasitária. / Abstract: This thesis is the result of a work that sought to discuss, as a general theme, the impact that parasites can have on the ecology of their hosts. It was divided into two chapters: the first chapter is a literature review that discusses how the parasites can influence the reproductive performance of their hosts; and the second chapter investigated in three species of anuran amphibians (Leptodactylus chaquensis, Leptodactylus podicipinus, and Hypsiboas raniceps), if the individuals parasitized by helminths are affected by changes in aspects of reproduction. The three species of anurans studied didn't present evidence that could have any relation between the parasite intensity of helminths and morphological characters associated to reproduction. This suggests that these species studied present immunological responses and/or physiological adaptations through parasitic infection. / Doutor

Dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Science in Medicine Johannesburg, 2004 / Malaria is the most prevalent parasitic disease in the world and the emergence of drug resistant strains of Plasmodium falciparum has made the search for new antimalarial drugs important. Protein kinases play an important role in cellular function and the phosphatidylinositol 3-kinase (PI3K) signal transduction pathway is implicated in diverse cellular processes such as glucose transport, cell survival and proliferation. A homology based approach identified an open reading frame (ORF) coding for the catalytic region of part of the 6.4 Kb ORF of PFE0765w gene sequence found at plasmoDB. The ORF consisted of 1 758 base pairs which coded for a 586 amino acid protein with a molecular weight of 68.5 KDa. The PfPI3K ORF was amplified from P.falciparum DNA, subcloned into an expression vector and the sequence verified. Analysis of the expressed protein obtained by Western blotting and probing with anti-His monoclonal antibody showed a protein of 68.5 KDa as well as some smaller products. / IT2018

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