Thesis (M.E.S.)--Evergreen State College, 2008. / "December, 2008." Title from title screen (viewed 4/8/2010). Includes bibliographical references (leaves 22-28).

Thesis (M.A.)--Humboldt State University, 2009. / Includes bibliographical references (leaves 100-103). Also available via Humboldt Digital Scholar.

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Made available in DSpace on 2014-06-11T19:30:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-10Bitstream added on 2014-06-13T20:20:39Z : No. of bitstreams: 1 angeli_a_me_rcla.pdf: 1869591 bytes, checksum: 14773e430c284b4384c16a0f78a22844 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O presente estudo tem como objetivos (1) realizar avaliação metodológica para determinação da medida mais adequada para estimar o tamanho das anêmonas, (2) obter dados sobre a variação temporal na riqueza, abundância e zonação das espécies de actiniários no entremarés rochoso e (3) verificar e quantificar o deslocamento de Bunodosma caissarum. Para o objetivo (1) foram tomadas variadas medidas in situ e ex situ de B. caissarum. O parâmetro morfométrico que apresentou menor variação entre campo e laboratório foi o diâmetro do disco pedal considerado, portanto, o mais adequado para estimativas de tamanho. O objetivo (2) foi estudado sazonalmente, na Praia da Enseada, Ubatuba (SP), por meio da demarcação de estratos com diferentes distâncias do limite inferior do entremarés. As espécies presentes foram Actinia bermudensis, Bunodosoma caissarum, Anthopleura cascaia, B. cangicum, Phyllactis flosculifera e um táxon não identificado. A distribuição das três primeiras espécies, mais abundantes, foi inversamente proporcional ao aumento da distância da água. As demais espécies não foram registradas em todas as estações e, com exceção do táxon não identificado, parecem ser mais relacionadas às regiões mais distantes da água. O objetivo (3) foi realizado em campo, na Ilha Urubuqueçaba, Santos (SP), e em laboratório, ambos por meio de mapeamento fotográfico. Em campo, as anêmonas em fenda apresentaram maior velocidade do que as anêmonas expostas. Em adição, demonstrou-se que sob ventos mais fortes e maiores ondas, as anêmonas deslocaram-se menos, provavelmente pela necessidade de maior adesão ao substrato. Em laboratório verificou-se a influência de organismos em contato físico, salinidade e profundidade sobre o deslocamento... / The objectives of this study are to (1) perform a methodological evaluation in order to determine the most suitable measure to estime anemones’ size, (2) obtain data regarding to seasonal variation of richness, abundance and zonation of Anthozoa species, and (3) verify and quantify the locomotion of Bunodosoma caissarum. In objective (1) several morphometric parameters of B. caissarum were measured in situ and ex situ. Pedal disk diameter showed the smallest variation among field and laboratory, this way being considered the most suitable to size estimates. The objective (2) was seasonally realized at Enseada Beach, Ubatuba (SP), through the demarcation of horizontal transects with distinct distances from the lower limit of intertidal zone. Six species were found: Actinia bermudensis, Bunodosoma caissarum, Anthopleura cascaia, B. cangicum, Phyllactis flosculifera and a nonidentified taxa. The distribution of the first three species was inversely proportional to the increasing of distance from water. The other species were not recorded in all seasons and, except for the non-identified taxa, seem to be more adapted to areas farther from the water. The objective (3) was performed in field at Urubuqueçaba Island, Santos (SP) and in laboratory both through photographic mapping. In field anemones located in fences moved faster than those in exposed sites, probably because they were in search of more favorable locations. Such conclusion matches the literature which indicates that sea anemones locomotion is associated with unfavorable conditions. In addition, it was demonstrated that anemones have lower mobility under stronger winds and larger waves probably due to the need of adhesion to substrate. It was verified in laboratory the influence of organisms in contact with anemones... (Complete abstract click electronic access below)

The relationship between clownfish and sea anemones is a beloved and iconic example of marine symbiosis. However, ecological information in the eastern Red Sea about the endemic Red Sea clownfish, Amphiprion bicinctus, and its host sea anemones remains relatively incomplete. For example, previous studies report that A. bicinctus forms mutualistic relationships with three to five host anemone species in the Red Sea. But the reported number and combination of host anemone species varies substantially among sources and little is known about host anemone distributions at different scales on the eastern coastline. To better understand the ecology of A. bicinctus and its host sea anemones, we conducted 70 surveys in three regions of Saudi Arabia and one region in Djibouti. We then analyzed distribution patterns for all anemone species observed in these regions, to attain deeper knowledge of anemone habitat usage and relative abundance. We recorded six host sea anemone species associated with A. bicinctus in the Red Sea, one of which represents a new case of symbiosis, and we identified differences in species composition and abundance across different reef scales. We noted patterns of decreasing anemone diversity with increasing latitude, beginning at 20° N, and greater overall anemone abundance in the central Red Sea. We also used field and laboratory observations to examine anemonefish abundance, survival, and fecundity on different species of anemones at different life history stages. In sum, this thesis collectively identifies eastern Red Sea anemone hosts for A. bicinctus, evaluates their regional and fine-scale distributions, and assesses how different anemone species impact their anemonefish occupants on different levels.

The first proof of the chemical mediation of nerve impulses by the peripheral release of specific chemicals was made by Loewi (1921). He demonstrated that during stimulation of the vagus nerve leading to an excised frog’s heart (Figure 1) a chemical mediator that he called Vagus-substance was released which slowed the action of the heart. This chemical mediator entered a perfusion fluid consisting of isotonic sodium chloride which was pumped out of the ventricle of the heart and diverted so as to drip onto a second frog's heart. The dripping perfusion medium slowed the pulsation of the second heart upon stimulation of the donor heart. When the stimulus was removed, the donor heart returned to normal pulsation and shortly after the recipient heart returned to normal. The Vagus-substance in the perfusion fluid was identified by Feldberg and Krayer (1933) as acetylcholine. Cholineacetylase forms acetylcholine from acetic acid and choline at the neuromuscular junction (Figure 2) in the presence of energy. The energy is obtained as a result of the action potential produced by the nerve impulse traveling along the nerve to the neuromuscular junction. The acetylcholine proceeds to cross the synapse at the neuromuscular junction and activates the muscle causing its contraction. The persistent presence of the acetylcholine at the junction would result in constant depolarization of the muscle resulting in fibrillation. The acetylcholine is destroyed by acetylcholinesterase causing repolarization so that the muscle is able to respond to further nerve impulses. Acetylcholine possesses two actions in vertebrates: muscarinic and nicotinic. The muscarinic action is exhibited at the neuromuscular functions of smooth muscle and sweat glands and the nicotine action is exhibited at the neuromuscular junction of striated muscle and at the synapse within ganglia.

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Thesis (Ph.D.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: p. 161-192.

The sea anemone Bartholomea annulata, is an ecologically important member of Caribbean coral reefs. This anemone serves as symbiotic host to crustacean associates, some of which may control parasite loads by "cleaning" reef fishes. Associates may gain protection from predation by dwelling with anemones. B. annulata was the most abundant anemone documented on three reefs, with 52% host to crustacean symbionts. Of those occupied by multi-species groups, 92% included Alpheus armatus shrimp. A. armatus is an important anemone associate providing protection to the anemone from predators such as Hermodice carunculata, in laboratory and field trials. H. carunculata can completely devour or severely damage prey anemones. Here I show that anemones hosting symbiotic alpheid shrimp are extremely less likely to sustain damage by predators than solitary anemones. The role of protector may be reciprocally provided by anemone and decapod associates. / by Amber McCammon. / Thesis (M.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

A peçonha de anêmonas do mar é uma fonte conhecida de compostos bioativos, incluindo peptídeos, que atuam em canais voltagem-dependentes. Foram descritos 4 tipos de neurotoxinas de anêmonas do mar, que atuam em canais NaV e 4 tipos que atuam em canais KV. Essas toxinas têm permitido discriminar subtipos de canais voltagem-dependentes, estreitamente relacionados, e constituem poderosas ferramentas para estudar o funcionamento e estrutura desses canais. Neste estudo, foram isolados e caracterizados três peptídeos da fração neurotóxica da anêmona do mar Anthopleura cascaia. Esses peptídeos foram nomeados como AcaIII1425, AcaIII2970 e AcaIII3090, onde Aca faz referência a espécie e os números seguem os resultados obtidos nas etapas de purificação. A peçonha foi extraída por meio de estímulos elétricos e purificada por gel-filtração (Sephadex G-50) e fase reversa por HPLC (C-18). As massas moleculares foram obtidas por meio de MALDI-TOF, apresentando 3337,4 Da para a AcaIII1425, 4881,7 Da para a AcaIII2970 e 4880,5 Da para AcaIII3090. Através da técnica de voltage-clamp, esses peptídeos foram testados em diferentes subtipos de canais NaV e KV expressados em ovócito de Xenopus. As toxinas AcaIII2970 e AcaIII3090 retardam, de maneira seletiva, a inativação rápida dos subtipos rNaV1.3, mNaV1.6 e hNaV1.5, enquanto que as outras isoformas testadas permaneceram inalteradas. É importantemente salientar que, a AcaIII2970 e AcaIII3090 também foram examinadas no canal de inseto DmNaV1, revelando uma clara \"filo-seletividade\" na eficácia da atividade das toxinas. A AcaIII2970 e AcaIII3090 inibem fortemente a inativação do canal NaV de inseto, resultando em um aumento na amplitude do pico da corrente e removendo completamente a inativação rápida. Para quantificarmos essa \"filo-seletividade\", foram construídas curvas da dependência da concentração no retardo da inativação induzida pelas toxinas AcaIII2970 e AcaIII3090 nos canais em que apresentaram maior eficácia. Os IC50 foram obtidos após a plotagem dos dados em uma curva sigmoidal. Para a AcaIII2970, os seguintes valores de IC50 foram obtidos: DmNaV1 = 162,19 ± 11,22 nM, mNaV1.6 = 645,92 ± 18,52 nM, rNaV1.3 = 572,56 ± 44,96 nM. Para a AcaIII3090, os seguintes valores de IC50 foram obtidos: DmNaV1 = 99,03 ± 9,25 nM, mNaV1.6 = 158,30 ± 33,86 nM, rNaV1.3 = 371,60 ± 6,48 nM. A AcaIII1425 atua, bloqueando, de modo seletivo os subtipos rKV1.1, rKV1.6 e rKV4.3, enquanto que as outras isoformas testadas permaneceram inalteradas. Devido à maior especificidade da toxina AcaIII1425 pelos subtipos rKV1.1 e rKV1.6, foram realizados ensaios de bloqueio da corrente do canal em função da concentração da toxina (curva dose-resposta). Os valores de IC50 para os subtipos rKV1.1 e rKV1.6 são de 7642,98 ±1601,65 nM e 241,65 ±4,27 nM, respectivamente. Desta forma, a AcaIII1425 é cerca de 32 vezes mais potente em canais do subtipo rKV1.6 do que em relação aos canais do subtipo rKV1.1. A estrutura primária das toxinas foram determinadas por degradação de Edman. A sequência parcial da AcaIII2970 e AcaIII3090 revelou que estas são similares a toxinas de canal de sódio do tipo1 de anêmonas do mar. A sequência completa da AcaIII1425 não apresenta similaridade com toxinas de anêmonas do mar, mas é similar a toxinas de Conus e aranha que possuem um motivo estrutural conhecido como ICK. Dessa forma, propomos que a AcaIII1425 seja um novo grupo de toxinas de anêmonas do mar que bloqueiam KV. Dado o ineditismo da toxina AcaIII1425, foram feitos experimentos in silico para obtermos um maior refinamento do mecanismo de interação entre a toxina e o canal rKV1.6. Estes experimentos indicaram que diferentes regiões dos canais KV são importantes para a seletividade e potência da toxina, corroborando com as propostas que vem sendo descritas / The venom of sea anemones is a known source of bioactive compounds, including peptides that act on voltage-gated ion channels. Four types of neurotoxins from sea anemones, acting on NaV channels, and four types acting on KV channels, have been reported. These toxins have developed the ability to discriminate closely related subtypes of voltage-gated channels, making them powerful tools to studying the function and structure of these channels. In this study, we isolated and characterized three peptides of the neurotoxic fraction from the venom of the sea anemone Anthopleura cascaia. These peptides were named as AcaIII1425, and AcaIII2970 AcaIII3090, where Aca refers to the species and the following numbers refer to results obtained in the purification steps. The venom was milked by electric shock and purified by molecular exclusion (Sephadex G-50) and reverse phase HPLC (C-18). Their molecular weights are 3337.4 Da to AcaIII1425, 4881.7 Da to AcaIII2970 and 4880.5 Da to AcaIII3090, obtained through a MALDI-TOF. Using the voltage-clamp technique, we have assayed the effects of these peptides on different subtypes of NaV and KV channels expressed in Xenopus oocytes. AcaIII2970 and AcaIII3090 toxins selectively slow down the fast inactivation of rNaV1.3, mNaV1.6 and hNaV1.5 subtypes, while the other mammalian isoforms remained unaffected. Importantly, AcaIII2970 and AcaIII3090 were also examined in insect DmNaV1 channel, revealing a clear phyla-selectivity with regards to the efficacy of the toxin. AcaIII2970 and AcaIII3090 strongly inhibit the inactivation of the insect NaV channel, resulting in an increase in the amplitude of the peak current, and complete removal of the fast and steady-state inactivation. In order to quantify this \"phyla-selectivity\", curves of the concentration dependence of the delayed inactivation induced by AcaIII2970 and AcaIII3090 toxins channels with higher efficacy, were built. After plotting the data on a sigmoidal curve the IC50 values were obtained. For AcaIII2970, the following IC50 values were obtained: DmNaV1 = 162.19 ± 11.22 nM, mNaV1.6 = 645.92 ± 18.52 nM and rNaV1.3 = 572.56 ± 44.96 nM. For AcaIII3090, the following IC50 values were obtained: DmNaV1 = 99.03 ± 9.25 nM, mNaV1.6 = 158.30 ± 33.86 nM and rNaV1.3 = 371.60 ± 6.48 nM. AcaIII1425 acts, selectively, blocking rKV1.1, rKV1.6 and rKV4.3 subtypes, while the others isoforms tested remained unaltered. Due the higher specificity of AcaIII1425 to rKV1.1 and rKV1.6 subtypes, assays were performed to evaluate the blocking channel current versus toxin concentration (dose-response curve). IC50 values for the subtypes rKV1.6 and rKV1.1 are 7642.98 ± 1601.65 nM and 241.65 ± 4.27 nM, respectively. Thus, AcaIII1425 is about 32 times more potent in the rKV1.6 than in the rKV1.1 channel. The primary structure of the toxins was determined by the Edman degradation. The partial sequence of AcaIII2970 and AcaIII3090 revealed that these toxins are similar to the type 1 sodium channel sea anemones neurotoxins. The complete sequence of AcaIII1425 has no similarity with other sea anemone toxins, but is similar to the Conus and spider neurotoxins which have a structural motif known as ICK. Thus, we propose that AcaIII1425 comprises a new group of sea anemones toxins that block KV channels. Given the unprecedented nature of the toxin AcaIII1425, in silico assays were carried out in order to further refining the proposed mechanism underlying the interaction between the toxin and the rKV1.6 channel. The results indicate that, in agreement to what has been proposed elsewhere, different regions of the KV channels are important for the toxin selectivity and potency