976 resultados para cytochrome b6


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The resolution of evolutionary relationships among deep-sea incirrate octopuses has been hindered by the paucity of individuals available for morphological studies and by the lack of tissue samples preserved using fixatives compatible with simple DNA extraction techniques. Evolutionary relationships from 11 species of deep-sea incirrate octopuses were investigated using 2392 base pairs (bp) of DNA from four mitochondrial genes (12S rDNA, 16S rDNA, cytochrome c oxidase subunit III, and cytochrome b) and the nuclear gene, rhodopsin. Morphological examination of these species was also undertaken. Molecular analyses distinguish a species of octopus from hydrothermal vents at Manus Basin from the vent octopodid Vulcanoctopus hydrothermalis known from vents on the East Pacific Rise. Both are herein considered members of the clade currently assigned the name Benthoctopus, although taxonomic implications preclude formally naming Vulcanoctopus as a junior synonym. Morphological investigations led to the conclusion that Benthoctopus macrophallus is a junior synonym of Benthoctopus yaquinae. An amended diagnosis of Benthoctopus is provided with additional information on male reproductive characteristics. Copyright © 2009 · Magnolia Press.

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Painterly rendering has been linked to computer vision, but we propose to link it to human vision because perception and painting are two processes that are interwoven. Recent progress in developing computational models allows to establish this link. We show that completely automatic rendering can be obtained by applying four image representations in the visual system: (1) colour constancy can be used to correct colours, (2) coarse background brightness in combination with colour coding in cytochrome-oxidase blobs can be used to create a background with a big brush, (3) the multi-scale line and edge representation provides a very natural way to render fi ner brush strokes, and (4) the multi-scale keypoint representation serves to create saliency maps for Focus-of-Attention, and FoA can be used to render important structures. Basic processes are described, renderings are shown, and important ideas for future research are discussed.

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Dissertação de mest., Biologia Marinha, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2008

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The fire salamander complex is quite diverse in the Iberian Peninsula where nine subspecies of Salamandra salamandra are currently recognized. Here, we analysed the geographical distribution of the subspecies S. s. gallaica and S. s. crespoi using partial sequences of the mitochondrial cytochrome b gene of 168 individuals from 12 locations in Portugal. Our results support the existence of a deep lineage divergence between the two subspecies, with non-overlapping geographical distributions except in two contact zones: one in Sesimbra on the western coast, and another in Alcoutim on the southeastern border with Spain. Moreover, S. s. crespoi displays signs of gene flow among the sampled locations whereas S. s. gallaica shows evidence of some restriction to gene flow. Present-day genetic make-up of S. s. gallaica and S. s. crespoi is a result of past historical events, fine-tuned by contemporary Iberian geoclimate. Humid mountain areas were found to harbour increased genetic diversity possibly acting as past refugia during drier interglacial periods. To analyse wider geographical patterns and lineage splitting events within S. salamandra we performed a Bayesian dating analysis completing our data set with previously published sequences. The observed divergences were associated to successive biogeographic scenarios, and to other Iberian species showing similar trends.

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Infectious diseases often hamper the production of aquatic organisms in aquaculture systems, causing economical losses, environmental problems and consumer safety issues. The conventional way aquaculture producers had to control pathogens was by means of synthetic antibiotics and chemicals. This procedure had consequences in the emergence of more resilient pathogens, drug contamination of seafood products and local ecosystems. To avoid the repercussions of antibiotic use, vaccination has greatly replaced human drugs in western fish farms. However there is still massive unregulated antibiotic use in third world fish farms, so less expensive therapeutic alternatives for drugs are desperately needed. An alternative way to achieve disease control in aquaculture is by using natural bioactive organic compounds with antibiotic, antioxidant and/or immunostimulant properties. Such diverse biomolecules occur in bacteria, algae, fungi, higher plants and other organisms. Fatty acids, nucleotides, monosaccharides, polysaccharides, peptides, polyphenols and terpenoids, are examples of these substances. One promising source of bioactive compounds are salt tolerant plants. Halophytes have more molecular resources and defence mechanisms, when compared with other tracheophytes, to deal with the oxidative stresses of their habitat. Many halophytes have been used as a traditional food and medical supply, especially by African and Asian cultures. This scientific work evaluated the antibiotic, antioxidant, immunostimulant and metal chelating properties of Atriplex halimus L., Arthrocnemum macrostachyum Moric., Carpobrotus edulis L., Juncus acutus L. and Plantago coronopus L., from the Algarve coast. The antibiotic properties were tested against Listonella anguillarum, Photobacterium damselae piscicida and Vibrio fischeri. The immunostimulant properties were tested with cytochrome c and Griess assays on Sparus aurata head-kidney phagocytes. J. acutus ether extract inhibited the growth of P. damselae piscicida. A. macrostachyum, A. halimus, C. edulis, Juncus acutus and P. coronopus displayed antioxidant, copper chelating and iron chelating properties. These plants show potential as sources of bioactive compounds with application in aquaculture and in other fields.

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Cytochromes P450 constitute a super-family of enzymes involved in the metabolism of Xenobiotics, where human cytochrome P450 3A4 is the most abundant of all P450s, accounting for about 50% of all human liver cytochromes. This membrane anchored protein is responsible for the metabolization of a wide array of environmental drugs and intoxicants, mainly due to its haem domain properties, and active site cavity volume. These properties make this protein an excellent subject for biosensor application, although CYO3A4 enzyme is also famous for its instability. Enzyme inactivation at room temperature is a normal conversion process that this enzyme undergoes, that may hamper any biosensing approach.

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First described more that 150 years ago, the systematics of the genera Geomalacus and Letourneuxia (Arionidae, Gastropoda, Pulmonata) is still challenging. The taxonomic classification of arionid species is based on extremely labile characters such as body size or color that depends both on diet and environment, as well as age. Moreover, there is little information on the genetic diversity and population structure of the Iberian slugs that could provide extra clues to disentangle their problematic classification. The present work uses different analytical tools such as habitat suitability (Ecological Niche Modeling - ENM), cytogenetic analysis and phylogeography to establish the geographical distribution and evolutionary history of these pulmonate slugs. The potential distribution of the four Geomalacus species was modeled using ENM, which allowed the identification of new locations for G. malagensis, including a first report in Portugal. Also, it was predicted a much wider distribution for G. malagensis and G. oliveirae than previously known. Classical cytogenetic analyses were assayed with reproductive and a novel use of somatic tissues (mouth and tentacles) returning the number of chromosomes for the four Geomalacus species and L. numidica (n = 31, 2n = 62) and the respective karyotypes. G. malagensis and L. numidica present similar chromosome morphologies and karyotypic formulae, being more similar to each other than the Geomalacus among themselves. We further reconstructed the phylogeny of the genera Geomalacus and Letourneuxia using partial sequences of the mitochondrial cytochrome oxidase subunit I (COI) and the nuclear ribosomal small subunit (18S rRNA), and applied an independent evolutionary rate method, the indicator vectors correlation, to evaluate the existence of cryptic diversity within species. The five nominal species of Geomalacus and Letourneuxia comprise 14 well-supported cryptic lineages. Letourneuxia numidica was retrieved as a sister group of G. malagensis. G. oliveirae is paraphyletic with respect to G. anguiformis. According to our dating estimates, the most recent common ancestor of Geomalacus dates back to the Middle Miocene (end of the Serravallian stage). The major lineage splitting events within Geomalacus occurred during the dry periods of the Zanclean stage (5.3-3.6 million years) and some lineages were confined to more humid mountain areas of the Iberian Peninsula, which lead to a highly geographically structured mitochondrial genetic diversity. The major findings of this are the following: (1) provides updated species distribution maps for the Iberian Geomalacus expanding the known geographic distribution of the concerned species, (2) unravels the cryptic diversity within the genera Geomalacus and Letourneuxia, (3) Geomalacus oliveirae is paraphyletic with G. anguiformis and (4) Letourneuxia numidica is sister group of G. malagensis.

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Im Rahmen seiner Forschungsaufgaben hat das Institut für Betriebswirtschaft und Marktforschung den Einfluss der Kapazitätsgröße und -auslastung auf den Kostenverlauf von 8 ausgewählten Molkereiproduktionsabteilungen untersucht und die Ergebnisse 1975/76 in "Milchwissenschaft", "Deutsche Molkereizeitung" und "Nordeuropäische Molkerei-Zeitschrift" veröffentlicht. Inzwischen sind die Modellkalkulationen überarbeitet und die Kosten auf den Preisstand von Januar 1976 umgewertet worden. Diese Kalkulationen bilden die Basis für die Ermittlung des Personalkosteneinflusses auf die Kapazitätsgröße von Molkereiabteilungen.

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Kurze Darstellung zur Kostenanalyse der Kälteversorgung in Molkereien.

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Die Kostenanalyse zur Bestimmung des Einflusses der Kapazitätsgröße und -auslastung auf den Kostenverlauf von Hilfskostenstellen (Hilfsabteilungen) erfolgt mit Hilfe von Modellkalkulationen. Eine spezielle Form der Teilkostenrechnung ermöglicht die Zurechnung der Kosten nach Kostenkategorien (jahresfix, tagesfix, ggf. chargenfix und mengenproportional) auf die entsprechenden Kostenträger (z. B. Kälte, Dampf) der jeweiligen Hilfskostenstelle. Durch computergestützte Simulationen können die Auswirkungen der verschiedenen Kosteneinflußfaktoren im einzelnen quantifiziert werden.

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Die Kostenuntersuchung umfasst die Produktionskosten für Edamerkäse, 40 % F. i. Tr., in Blockform (rd. 16 kg) bei Anwendung des Bergs-Maskin-Verfahrens.

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Tese de doutoramento, Farmácia (Química Farmacêutica e Terapêutica), Universidade de Lisboa, Faculdade de Farmácia, 2014

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Tese de doutoramento, Farmácia (Bioquímica), Universidade de Lisboa, Faculdade de Farmácia, 2014

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Thesis (Master's)--University of Washington, 2014

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Alcohol binge drinking, especially in teenagers and young adults is a major public health issue in the UK, with the number of alcohol related liver disorders steadily increasing. Understanding the mechanisms behind liver disease arising from binge-drinking and finding ways to prevent such damage are currently important areas of research. In the present investigation the effect of acute ethanol administration on hepatic oxidative damage and apoptosis was examined using both an in vivo and in vitro approach; the effect of micronutrient supplementation prior and during ethanol exposure was also studied. The following studies were performed: (1) ethanol administration (75 mmol/kg body weight) and cyanamide pre-treatment followed by ethanol to study elevated acetaldehyde levels with liver tissue analysed 2.5, 6 and 24 hours post-alcohol; (2). Using juvenile animals, 2% betaine supplementation followed by acute ethanol with tissue analysed 24 hrs post ethanol; and (3). Micronutrient supplementation during concomitant ethanol exposure to hepG2 cells. It was found that a single dose of alcohol caused oxidative damage to the liver of rats at 2.5 hr post-alcohol as evidenced by decreased glutathione levels and increased malondialdehyde levels in both the cytosol and mitochondria. Liver function was also depressed but there were no findings of apoptosis as cytochrome c levels and caspase 3 activity was unchanged. At 6 hours, the effect of ethanol was reduced suggesting some degree of recovery, however, by 24 hours, increased mitochondrial oxidative stress was apparent. The effect of elevated acetaldehyde on hepatic damage was particularly evident at 24 hours, with some oxidative changes at earlier time points. At 24 hours, acetaldehyde caused a profound drop in glutathione levels in the cytosol and hepatic function was still deteriorating. Studies examining ethanol exposure to juvenile livers showed that glutathione levels were increased, suggesting an overtly protective response not seen in with older animals. It also showed that despite cytochrome c release into the cytosol, caspase-3 levels were not increased. This suggests that ATP depletion is preventing apoptosis initiation. Betaine supplementation prevented almost all of the alcohol-mediated changes, suggesting that the main mechanism behind alcohol-mediated liver damage is oxidative stress. Results using the hepG2 cell line model showed that micronutrients involved in glutathione synthesis can protect against hepatocyte damage caused by alcohol metabolism, with reduced reactive oxygen species and increased/maintained glutathione levels. In summary, these results demonstrate that both acute alcohol and acetaldehyde can have damaging effects to the liver, but that dietary intervention may be able to protect against ethanol induced oxidative stress.