171 resultados para Octopus


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Gullfaks is one of the four major Norwegian oil and gas fields, located in the northeastern edge of the North Sea Plateau. Tommeliten lies in the greater Ekofisk area in the central North Sea. During the cruises HE 208 and AL 267 several seep locations of the North Sea were visited. At the Heincke seep at Gullfaks, sediments were sampled in May 2004 (HE 208) using a video-guided multiple corer system (MUC; Octopus, Kiel). The samples were recovered from an area densely covered with bacterial mats where gas ebullition was observed. The coarse sands limited MUC penetration depth to maximal 30 centimeters and the highly permeable sands did not allow for a high-resolution, vertical subsampling because of pore water loss. The gas flare mapping and videographic observation at Tommeliten indicated an area of gas emission with a few small patches of bacterial mats with diameters <50 cm from most of which a single stream of gas bubbles emerged. The patches were spaced apart by 10-100 m. Sampling of sediments covered by bacterial mats was only possible with 3 small push cores (3.8 cm diameter) mounted to ROV Cherokee. These cores were sampled in 3 cm intervals. Lipid biomarker extraction from 10 -17 g wet sediment was carried out as described in detail elsewhere (Elvert et al., 2003; doi:10.1080/01490450303894). Briefly, defined concentrations of cholestane, nonadecanol and nonadecanolic acid with known delta 13C-values were added to the sediments prior to extraction as internal standards for the hydrocarbon, alcohol and fatty acid fraction, respectively. Total lipid extracts were obtained from the sediment by ultrasonification with organic solvents of decreasing polarity. Esterified fatty acids (FAs) were cleaved from the glycerol head group by saponification with methanolic KOH solution. From this mixture, the neutral fraction was extracted with hexane. After subsequent acidification, FAs were extracted with hexane. For analysis, FAs were methylated using BF3 in methanol yielding fatty acid methyl esters (FAMES). The fixation for total cell counts and CARD-FISH were performed on-board directly after sampling. For both methods, sediments were fixed in formaldehyde solution. After two hours, aliquots for CARD-FISH staining were washed with 1* PBS (10mmol/l sodium phosphate solution, 130mmol/l NaCl, adjusted to a pH of 7.2) and finally stored in a 1:1 PBS:ethanol solution at -20°C until further processing. Samples for total cell counts were stored in formalin at 4°C until analysis. For sandy samples, the total cell count/CARD-FISH protocol was optimized to separate sand particles from the cells. Cells were dislodged from sediment grains and brought into solution with the supernatant by sonicating each sample onice for 2 minutes at 50W. This procedure was repeated four times and supernatants were combined. The sediment samples were brought to a final dilution of 1:2000 to 1:4000 and filtered onto 0.2µm GTTP filters (Millipore, Eschbonn, Germany).

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In vertebrate visual pigments, a glutamic acid serves as a negative counterion to the positively charged chromophore, a protonated Schiff base of retinal. When photoisomerization leads to the Schiff base deprotonating, the anionic glutamic acid becomes protonated, forming a neutral species that activates the visual cascade. We show that in octopus rhodopsin, the glutamic acid has no anionic counterpart. Thus, the “counterion” is already neutral, so no protonated form of an initially anionic group needs to be created to activate. This helps to explain another observation—that the active photoproduct of octopus rhodopsin can be formed without its Schiff base deprotonating. In this sense, the mechanism of light activation of octopus rhodopsin is simpler than for vertebrates, because it eliminates one of the steps required for vertebrate rhodopsins to achieve their activating state.

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We present here the description of genes coding for molluscan hemocyanins. Two distantly related mollusks, Haliotis tuberculata and Octopus dofleini, were studied. The typical architecture of a molluscan hemocyanin subunit, which is a string of seven or eight globular functional units (FUs, designated a to h, about 50 kDa each), is reflected by the gene organization: a series of eight structurally related coding regions in Haliotis, corresponding to FU-a to FU-h, with seven highly variable linker introns of 174 to 3,198 bp length (all in phase 1). In Octopus seven coding regions (FU-a to FU-g) are found, separated by phase 1 introns varying in length from 100 bp to 910 bp. Both genes exhibit typical signal (export) sequences, and in both cases these are interrupted by an additional intron. Each gene also contains an intron between signal peptide and FU-a and in the 3′ untranslated region. Of special relevance for evolutionary considerations are introns interrupting those regions that encode a discrete functional unit. We found that five of the eight FUs in Haliotis each are encoded by a single exon, whereas FU-f, FU-g, and FU-a are encoded by two, three and four exons, respectively. Similarly, in Octopus four of the FUs each correspond to an uninterrupted exon, whereas FU-b, FU-e, and FU-f each contain a single intron. Although the positioning of the introns between FUs is highly conserved in the two mollusks, the introns within FUs show no relationship either in location nor phase. It is proposed that the introns between FUs were generated as the eight-unit polypeptide evolved from a monomeric precursor, and that the internal introns have been added later. A hypothesis for evolution of the ring-like quaternary structure of molluscan hemocyanins is presented.

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Thesis (Ph.D.)--University of Washington, 2016-06

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The Octopus Automated Perimeter was validated in a comparative study and found to offer many advantages in the assessment of the visual field. The visual evoked potential was investigated in an extensive study using a variety of stimulus parameters to simulate hemianopia and central visual field defects. The scalp topography was recorded topographically and a technique to compute the source derivation of the scalp potential was developed. This enabled clarification of the expected scalp distribution to half field stimulation using different electrode montages. The visual evoked potential following full field stimulation was found to be asymmetrical around the midline with a bias over the left occiput particularly when the foveal polar projections of the occipital cortex were preferentially stimulated. The half field response reflected the distribution asymmetry. Masking of the central 3° resulted in a response which was approximately symmetrical around the midline but there was no evidence of the PNP-complex. A method for visual field quantification was developed based on the neural representation of visual space (Drasdo and Peaston 1982) in an attempt to relate visual field depravation with the resultant visual evoked potentials. There was no form of simple, diffuse summation between the scalp potential and the cortical generators. It was, however, possible to quantify the degree of scalp potential attenuation for M-scaled full field stimuli. The results obtained from patients exhibiting pre-chiasmal lesions suggested that the PNP-complex is not scotomatous in nature but confirmed that it is most likely to be related to specific diseases (Harding and Crews 1982). There was a strong correlation between the percentage information loss of the visual field and the diagnostic value of the visual evoked potential in patients exhibiting chiasmal lesions.

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Animal celebrity is a human creation informing us about our socially constructed natural world. It is relational, expressive of cultural proclivities, political power plays and the quotidian everyday, as well as serious philosophical reflections on the meaning of being human. This article attempts to outline some key contours in the genealogy of animal celebrity, showing how popular culture, including fairground attractions, public relations, Hollywood movies, documentary films, zoo attractions, commercial sport and mediatised moral panics - particularly those accompanying scientific developments such as cloning - help to order, categorise and license aspects of human understanding and feelings. The nature of [animal] charisma and celebrity are explored with assistance from Jumbo the Elephant, Guy the Gorilla, Paul the clairvoyant octopus, Uggie the film star, Nénette the orang-utan and Dolly the sheep. It argues that the issue of what it is to be human lies beneath the celebritised surface or, as Donna Haraway noted, the issue 'of having to face oneself'. © 2013 Taylor & Francis.

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Oxygen equilibrium curves have been widely used to understand oxygen transport in numerous organisms. A major challenge has been to monitor oxygen binding characteristics and concomitant pH changes as they occur in vivo, in limited sample volumes. Here we report a technique allowing highly resolved and simultaneous monitoring of pH and blood pigment saturation in minute blood volumes. We equipped a gas diffusion chamber with a broad range fibre optic spectrophotometer and a micro-pH optode and recorded changes of pigment oxygenation along PO2 and pH gradients to test the setup. Oxygen binding parameters derived from measurements in only 15 µl of haemolymph from the cephalopod Octopus vulgaris showed low instrumental error (0.93%) and good agreement with published data. Broad range spectra, each resolving 2048 data points, provided detailed insight into the complex absorbance characteristics of diverse blood types. After consideration of photobleaching and intrinsic fluorescence, pH optodes yielded accurate recordings and resolved a sigmoidal shift of 0.03 pH units in response to changing PO2 from 0-21 kPa. Highly resolved continuous recordings along pH gradients conformed to stepwise measurements at low rates of pH changes. In this study we showed that a diffusion chamber upgraded with a broad range spectrophotometer and an optical pH sensor accurately characterizes oxygen binding with minimal sample consumption and manipulation. We conclude that the modified diffusion chamber is highly suitable for experimental biologists who demand high flexibility, detailed insight into oxygen binding as well as experimental and biological accuracy combined in a single set up.

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The purpose of this dissertation is to contribute to a better understanding of how global seafood trade interacts with the governance of small-scale fisheries (SSFs). As global seafood trade expands, SSFs have the potential to experience significant economic, social, and political benefits from participation in export markets. At the same time, market connections that place increasing pressures on resources pose risks to both the ecological and social integrity of SSFs. This dissertation seeks to explore the factors that mediate between the potential benefits and risks of global seafood markets for SSFs, with the goal of developing hypotheses regarding these relationships.

The empirical investigation consists of a series of case studies from the Yucatan Peninsula, Mexico. This is a particularly rich context in which to study global market connections with SSFs because the SSFs in this region engage in a variety of market-oriented harvests, most notably for octopus, groupers and snappers, lobster, and sea cucumber. Variation in market forms and the institutional diversity of local-level governance arrangements allows the dissertation to explore a number of examples.

The analysis is guided primarily by common-pool resource (CPR) theory because of the insights it provides regarding the conditions that facilitate collective action and the factors that promote long-lasting resource governance arrangements. Theory from institutional economics and political ecology contribute to the elaboration of a multi-faceted conceptualization of markets for CPR theory, with the aim of facilitating the identification of mechanisms through which markets and CPR governance actually interact. This dissertation conceptualizes markets as sets of institutions that structure the exchange of property rights over fisheries resources, affect the material incentives to harvest resources, and transmit ideas and values about fisheries resources and governance.

The case studies explore four different mechanisms through which markets potentially influence resource governance: 1) Markets can contribute to costly resource governance activities by offsetting costs through profits, 2) markets can undermine resource governance by generating incentives for noncompliance and lead to overharvesting resources, 3) markets can increase the costs of resource governance, for example by augmenting monitoring and enforcement burdens, and 4) markets can alter values and norms underpinning resource governance by transmitting ideas between local resource users and a variety of market actors.

Data collected using participant observation, survey, informal and structured interviews contributed to the elaboration of the following hypotheses relevant to interactions between global seafood trade and SSFs governance. 1) Roll-back neoliberalization of fisheries policies has undermined cooperatives’ ability to achieve financial success through engagement with markets and thus their potential role as key actors in resource governance (chapter two). 2) Different relations of production influence whether local governance institutions will erode or strengthen when faced with market pressures. In particular, relations of production in which fishers own their own means of production and share the collective costs of governance are more likely to strengthen resource governance while relations of production in which a single entrepreneur controls capital and access to the fishery are more likely to contribute to the erosion of resource governance institutions in the face of market pressures (chapter three). 3) By serving as a new discursive framework within which to conceive of and talk about fisheries resources, markets can influence norms and values that shape and constitute governance arrangements.

In sum, the dissertation demonstrates that global seafood trade manifests in a diversity of local forms and effects. Whether SSFs moderate risks and take advantage of benefits depends on a variety of factors, and resource users themselves have the potential to influence the outcomes of seafood market connections through local forms of collective action.

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Extracto de pulpo como suplemento para el cultivo y criopreservación de tejido y de células en suspensión de invertebrados marinos. La presente invención se refiere a un procedimiento para obtención de un suplemento para el cultivo in vitro y criopreservación de tejido y de células en suspensión de invertebrados marinos a base de extracto acuoso de pulpo homogeneizado y la utilización de dicho suplemento preparación de medios para la criopreservación de células en suspensión y de tejidos de organismos invertebrados marinos.

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During 1920-1921, Mr. Krempf, Director of the Fisheries and Oceanographic Service of Indochina, collected samples of cephalopods in different places along the coast of Indochina, especially on the island of Poulo-Condor, located about 100 miles east from Camau. The present paper deals with the description of Sepia harmeri, Loligo singhalensis, Sepioleuthis lessoniana, Sepioleuthis krempfi, Octopus fantonianus, Octopus dollfusi, Octopus tuberculatus.

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Uma análise de dados publicados sobre dietas de aves marinhas oceânicas mostra a predominância de cefalópodes musculares e de distribuição mais superficial nas camadas oceânicas, mas também são importantes as espécies gelatinosas e amoniacais restritas a camadas abaixo dos 300 m da superfície. A princípio, não deveria se esperar que cefalópodes de profundidade fossem considerados presas comuns de aves marinhas oceânicas como reportados por muitos autores. É proposto neste estudo que uma fonte indireta, importante e de fácil obtenção, surgiu com o início das atividades dos barcos atuneiros que operam com espinhel. O hábito de ingerir restos de vísceras de peixes capturados em barcos espinheleiros pode explicar as prováveis conclusões equivocadas de que cefalópodes de profundidade são presas naturais de aves marinhas oceânicas.