Thesis (M.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / A summary of the sex hormones found in the various animal phyla is given. The phylogenetic implications of steroid presence and mode of reproduction are discussed particularly in regard to the evolution to viviparity. By paper and gas chromatographic methods, the gonads of the male Pecten were analyzed for androgens. None of the standard hormones could be identified, but a steroid compound of unknown identity was suggested by the experimental evidence. / 2999-01-01

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Orientador: Flávio Dias Passos / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-20T10:56:39Z (GMT). No. of bitstreams: 1 Magalhaes_FredericoThomaisino_M.pdf: 177494137 bytes, checksum: 180836253ab4ccebefd0ddea49b4655e (MD5) Previous issue date: 2012 / Resumo: O Brasil aderiu ao "Tratado Antártico" em 1975, e desde 1982 mantém o "Programa Antártico Brasileiro. A partir de 1984 as pesquisas brasileiras se concentraram na Baía do Almirantado, na Ilha Rei George, onde se localiza a base do país. A Baía do Almirantado foi eleita uma "Área Antártica Especialmente Gerenciada" pelas Partes Consultivas do Tratado Antártico e trata-se de um local representativo do ecossistema costeiro antártico, principalmente em termos de distribuição e composição de espécies. Lá os pesquisadores tem estudado a fauna bentônica da região, entre eles os Mollusca, que são abundantes e importantes no estudo dos processos que determinam a estrutura e o funcionamento das comunidades bentônicas marinhas. Este estudo se focou na classe Bivalvia, provendo um novo material de referência para identificação destes animais, e mais especificamente daqueles da Baía do Almirantado, apresentando-se como um guia ilustrado, com descrições detalhadas das conchas dessas espécies. Além disso, dados de distribuição geográfica e batimétrica foram reunidos para uma análise dessa fauna, na tentativa de qualificar a importância da região das Ilhas Shetland do Sul como um local estratégico para estudos em biogeografia. Foram identificadas 39 espécies de 18 famílias distintas, e seus dados de biologia, distribuição batimétrica e geográfica reunidos. As famílias mais representativas foram Philobryidae, Nuculanidae e Lasaeidae, contabilizando 15 espécies. As regiões com mais espécies em comum com a área estudada foram o Estreito de Magalhães, Ilha Georgia do Sul, Mar de Weddell, Península Antártica e sul do Chile; regiões notáveis pela riqueza de Bivalvia. As famílias mais largamente distribuídas, encontradas neste estudo, foram LImidae e Carditidae; e as mais restritas foram Siliculidae e Nuculanidae. A espécie com maior distribuição foi Cyclocardia astartoides, e as mais restritas Ennucula georgiana e Mysella narchii. As espécies encontradas se concentram nas profundidades até 1000 m, com seu número caindo para menos da metade além disso. Apenas seis espécies ocorrendo além dos 2000 m: Yoldiella profundorum, Limopsis marionensis, Limopsis lilliei, Adacnarca nitens, Limatula pygmaea e Cyclocardia astartoides. Este estudo demonstram a região da Baía do Almirantado como abrigo de uma fauna de Bivalvia composta por espécies estritamente antárticas, e outras que ocorrem ao norte da Convergência Antártica; sendo assim uma região importante para o estudo da distribuição destes animais / Abstract: Brazil abided to the "Antarctic Treaty" in 1975, and since 1982 maintains the "Brazilian Antarctic Program". As from 1984 the Brazilian researches focused on Admiralty Bay, in King George Island, where the country?s Antarctic base is located. Admiralty Bay was elected a "Antarctic Especially Managed Area" by the Antarctic Treaty Consultative Parties and is a representative place for the Antarctic coastal ecosystem, especially in views of species distribution and composition. In there researchers have been studying the regional benthic fauna, amidst it the Mollusca, abundant and important animals for the study of determinant process in the structure and operation of the marine benthic community. The present study focused on the class Bivalvia, providing a new reference source for identification of the group, and specifically for those of Admiralty Bay, presented as an illustrated guide with detailed shell descriptions for all the species found. Furthermore, data on geographic and bathymetric distribution were gathered for an analysis of this fauna, in attempt to qualify the importance of the South Shetland Islands as a strategic place for studies on biogeography. Thirty-nine species, of 18 distinct families, were identified, and their biological, geographical and bathymetrical data gathered. The most representative families were Philobryidae, Nuculanidae and Lasaeidae, counting 15 species in sum. The geographic regions with more species in common with the studied area were Strait of Magellan, South Georgia Island, Weddell Sea, Antarctic Peninsula and Southern Chile; notable regions for Bivalvia richness. The families found with the largest geographic distribution were Limidae and Carditidae, and the most restricted ones were Siliculidae and Nuculanidae. The species with largest geographical distribution was Cyclocardia astartoides, while the most restricted were Ennucula georgiana and Mysella narchii. The species found in this study are concentrated in depths until 1000 m, beyond that their number shortens to less than half. Only six occur deeper than 2000 m: Yoldiella profundorum, Limopsis marionensis, Limopsis lilliei, Adacnarca nitens, Limatula pygmaea and Cyclocardia astaroides. The present study shows Admiralty Bay as shelter to a Bivalvia fauna with strictly Antarctic species and northern ones, common north to the Antarctic Convergence, thus being an important place for studying the distribution of these animals / Mestrado / Ecologia / Mestre em Ecologia

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In contrast to the much that is known about herbivory and its consequences, lichenovory has seldom been studied. Recently, studies confirming the anti-feedant role of lichen secondary metabolites were brought out and hypotheses considering the nature of these interactions were introduced. Also, a few papers dealing with the ecological consequences of lichenovory were published lately. My thesis was aimed on the secondary metabolites issue and the preferences of the lichen feeders in the natural conditions. Six epiphytic lichen species containing secondary compounds (Parmelia sulcata, P. saxatilis, Parmelina tiliacea, Melanelixia glabratula, M. subaurifera, M. glabra), two without them (Melanohalea exasperata, M. exasperatula) and two species of gastropods that naturally climb the trees to feed on lichens (Lehmannia marginata, Cochlodina cerata) were selected for grazing experiments. The deterring role of the lichen compounds was proven. These were also identified using thin-layer chromatography. Subsequently, a transplantation experiment was carried out. It was focused on specifying the preferences of lichen grazers in their natural habitat. The genus Melanohalea that does not contain any secondary metabolites was strongly prefered. No significant preferences among the other species used in the...

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1) Metallothioneins (MTs) are frequently proposed as biomarkers for metal exposure and toxicity in molluscs. However, various biotic and abiotic factors influencing the rate of MT synthesis, are not well understood. The objectives of this study are to investigate the effects of biotic factors (size, sex, growth rate, nutritional state, prey type) and abiotic factors (temperature, Cd or oxidative exposure) on MT induction in Nucella lapillus and Littorina littorea, and to evaluate the usefulness of applying MT as a monitoring tool. In this study, total MTs in tissue samples were quantified using the silver saturation method. 2) Induction of MT was monitored in N. lapillus during and after exposure to Cd. N. lapillus were exposed to 500 μg Cd 1-1 (2.2% of 96h LC50) for 60 d and then placed into clean seawater for 110 d. The concentration of MT in the whole animal increased during the exposure period, peaked at Day 70, and then declined gradually. The half-life of MT was ca. 40 d. Cd concentration increased throughout the period of exposure and while in clean seawater, levelling off only after Day 120, indicating that Cd concentration could not be regulated by N. lapillus. Highest MT induction and Cd accumulation were found in the Leiblein gland of N. lapillus, suggesting that measurement of MT induction in this tissue may prove useful as a sublethal biological response to Cd contamination. 3) The combined effects of Cd and water temperature on the oxygen consumption rate (MO2) and biochemistry of fasted N. lapillus were investigated. Inhibition of MO2 by Cd increased with increasing temperature and decreasing animal size. Cd exposure caused significant reductions in glycogen concentrations in N. lapillus at both temperatures (5 & 10°C). Cd-exposed N. lapillus showed significantly higher MT concentrations in the Leiblein gland at 10°C but not at 5°C, indicating that MT synthesis is temperature dependent. Reduction in MO2 may be directly linked to Cd-induced mucus production, structural damage to gills and reduction in oxygen carrying capacity of haemocyanin. However, metabolic depression, including low MO2, glycogen stores and activity in Cd-exposed N. lapillus, may be a strategy to minimise the uptake and toxicity of Cd, and energy expenditure to spare energy reserves for detoxification and maintenance. 4) The influences of nutritional state and prey type on the survival, growth, Cd accumulation, MT induction and glycogen stores in N. lapillus were studied. Prolonged starvation and Cd exposure synergistically reduced the survivorship of N. lapillus, but feeding could help N. lapillus to combat Cd toxicity and minimise mortality. Extended fasting also caused tissue wastage, leading to higher concentrations of Cd and MT in tissues, whereas fed animals increased in weight and had lower Cd and MT concentrations because of the tissue dilution effect. Prey type significantly affected growth rate of N. lapillus and indirectly influenced Cd accumulation, MT induction and glycogen stores. Eating mussels promoted better growth and higher glycogen reserves them eating barnacles. Individual growth rate decreased with increasing Cd accumulation. Cd-exposed survivors grew faster and consumed more than control animals, implying that these survivors may have better fitness and greater tolerance to Cd toxicity. 5) Investigation of the effect of hydrogen peroxide (H2O2), and the combined effect of H2O2 and Cd on MT induction and condition index (CI) in N. lapillus was conducted. Exposure to either Cd or H2O2 alone induced synthesis of MT or MT-like proteins in N. lapillus. Exposure to high H2O2 (1000 ppm) alone or combined with Cd, and exposure to Cd (0.50 ppm) or H2O2 (2.0 ppm), resulted in significant weight loss, indicated by a reduction of CL However, CIs of N. lapillus exposed to 0.5 ppm Cd + 2.0 ppm H2O2 or 0.25 ppm Cd + 2.0 ppm H2O2, were similar to that of the control suggesting that Cd antagonistically reduces toxicity caused by H2O2 since Cd-induced MT may have a protective function against hydroxyl radicals.