327 resultados para Etmopterus pusillus
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Em fevereiro e outubro de 1998, na área experimental da Fazenda de Ensino e Pesquisa da UNESP no município de Selvíria-MS (latitude 20° 22' S, longitude 51° 22' W, altitude 335 m), foi constatada a presença de mosca branca em mamoeiro cultivar Baixinho de Santa Amália, plantado no interior de um telado com malha de 2 x 2 mm. Essa área fazia parte de um experimento visando determinar o efeito do cultivo em ambiente protegido sobre o desenvolvimento das plantas, a produção de frutos e a ocorrência do mosaico do mamoeiro. Nas duas ocasiões os insetos foram enviados ao Centro de Recursos Genéticos e Biotecnologia (CENARGEN) da Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) para identificação. Na primeira infestação o material foi identificado como Trialeurodes sp. e na infestação de outubro como Bemisia tabaci biótipo B . Nos dois casos havia grande quantidade de ninfas nas folhas maduras e de adultos nas folhas novas. Para Trialeurodes sp. foi realizada uma contagem de ninfas em dezoito folhas, em cinco áreas de 1 cm² por folha, distribuídas ao acaso, encontrando-se a média de 7,6 ninfas por cm². Como conseqüência da presença das duas espécies, o único dano observado foi um intenso desenvolvimento de fumagina recobrindo completamente a superfície das folhas, que acabaram por secar e cair. A infestação de B. tabaci biótipo B foi controlada pela presença de larvas e adultos do coccinelídeo Delphastus pusillus (LeConte) que alimentavam-se vorazmente das ninfas presentes.
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A newly-isolated thermophilic strain of the zygomycete fungus Rhizomucor pusillus 13.36 produced highly active dextrinogenic and saccharogenic enzymes. Cassava pulp was a good alternative substrate for amylase production. Dextrinogenic and saccharogenic amylases exhibited optimum activities at a pH of 4.0-4.5 and 5.0 respectively and at a temperature of 75°C. The enzymes were highly thermostable, with no detectable loss of saccharogenic or dextrinogenic activity after 1 h and 6 h at 60°C, respectively. The saccharogenic activity was inhibited by Ca2+ while the dextrinogenic was indifferent to this ion. Both activities were inhibited by Fe2+ and Cu2+ Hydrolysis of soluble starch by the crude enzyme yielded 66% glucose, 19.5% maltose, 7.7% maltotriose and 6.6% oligosaccharides. Copyright © 2005, The Microbiological Society of Korea.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Lipases have important applications in biotechnological processes, motivating us to produce, purify, immobilize and perform a biochemical characterization of the lipase from Rhizomucor pusillus. The fungus was cultivated by solid state fermentation producing lipolytic activity of about 0.5 U/mL(4U/g). A partial purification by gel filtration chromatography in Se-phacryl S-100 allowed obtaining a yield of about 85% and a purification factor of 5.7. Our results revealed that the purified enzyme is very stable with some significant differences in its properties when compared to crude extract. The crude enzyme extract has an optimum pH and temperature of 7.5 ° C and 40 ° C, respectively. After purification, a shift of the optimum pH from 7 to 8 was observed, as well as a rise in optimumtemperature to 60 ° C and an increase in stability. The enzyme was immobilized on CNBr-Agarose and Octyl-Agarose supports, having the highest immobilization yield of 94% in the second resin. The major advantage of immobilization in hydrophobic media such as Octyl is in its hyper activation, which in this case was over 200%, a very interesting finding. Another advantage of this type of immobilization is the possibility of using the derivatives in biotechnological applications, such as in oil enriched with omega-3 as the results obtained in this study display the hydrolysis of 40% EPA and 7% DHA from sardine oil, promising results compared to the literature.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Robben sind amphibische marine Säugetiere. Das bedeutet, dass sie zweirnunterschiedliche Lebensräume, Wasser und Land, bewohnen. Ihre sensorischen Systeme müssen auf beide Medien abgestimmt sein. Gerade für das Sehvermögen ist es eine große Herausforderung, sich den zwei optisch unterschiedlichen Medien anzupassen. Deshalb sind Forscher an dem Sehen von marinen Säugern seit dem zwanzigsten Jahrhundert so sehr interessiert. rnBis heute wird kontrovers diskutiert, ob marine Säugetiere Farbe sehen können, da sie durch einen Gendefekt nur einen Zapfentyp besitzen und somit zu den Zapfen-Monochromaten gehören. Dressurexperimente zeigten jedoch, dass Seebären und Seelöwen in der Lage sind grüne und blaue Testfelder von Graustufen zu unterscheiden (Busch & Dücker, 1987; Griebel & Schmid, 1992).rnUm auszuschließen, dass die Tiere ein Farbensehen über die Unterscheidung von Helligkeit vortäuschen, wurde in der vorliegenden Arbeit zunächst die Kontrasterkennung untersucht und danach Tests auf Farbensehen durchgeführt. Als Versuchstiere dienten zwei Seehunde (Phoca vitulina) und zwei Südafrikanische Seebären (Arctocephalus pusillus). Alle Versuche wurden unter freien Himmel im Zoo Frankfurt durchgeführt. Den Tieren wurden immer drei Testfelder zur Auswahl geboten: zwei waren gleich und zeigten ein homogenen Hintergrund, das dritte zeigte ein Dreieck auf demselben Hintergrund. Die Tiere wurden auf das Dreieck dressiert. In den Versuchen zum Helligkeitskontrast wurden graue Dreiecke auf grauem Hintergrund verwendet. Das Dreieck wurde nicht erkannt bei einem Luminanz-Kontrast (K= LD/(LD+LH)) zwischen 0,03 und -0,12.rnBeim Test auf Farbensehen wurden die Farben Blau, Grün, Gelb und Orange auf grauem Hintergrund verwendet. Die Testreihen zeigten, dass jedes Tier auch in Bereichen von geringem Helligkeitskontrast hohe Wahlhäufigkeiten auf das farbige Dreieck erzielte und somit eindeutig die Farben Blau, Grün und Gelb sehen konnte. Lediglich bei der Farbe Orange kann keine Aussage zum Farbensehen getroffen werden, da das farbige Dreieck immer dunkler war als der Hintergrund. rnZusammenfassend konnte in dieser Arbeit gezeigt werden, dass Seehunde und Seebären in der Lage sind Farbe zu sehen. Vermutlich beruht diese Fähigkeit auf der Interaktion von Stäbchen und Zapfen. rn
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Gli squali bianchi sono tra i più importanti predatori dei Pinnipedi (Klimley et al., 2001; Kock, 2002). La loro principale strategia di caccia consiste nel pattugliare le acque circostanti ad una colonia di otarie e nell’attaccarle quando queste sono in movimento, mentre si allontanano o avvicinano all’isola (Klimley et al., 2001; Kock, 2002). Tuttavia, la strategia e la dinamica della predazione osservate anche in relazione al ciclo riproduttivo della preda e le tattiche comportamentali messe in atto dalla preda per ridurre la probabilità di predazione, e quindi diminuire la sua mortalità, sono ancora poco conosciute. Con questo studio, effettuato nell’area di Seal Island all’interno della baia di Mossel Bay in Sud Africa, abbiamo cercato di definire proprio questi punti ancora poco conosciuti. Per studiare la strategia e le dinamica di predazione dello squalo bianco abbiamo utilizzato il sistema di monitoraggio acustico, in modo da poter approfondire le conoscenze sui loro movimenti e quindi sulle loro abitudini. Per dare un maggiore supporto ai dati ottenuti con la telemetria acustica abbiamo effettuato anche un monitoraggio visivo attraverso l’attrazione (chumming) e l’identificazione fotografica degli squali bianchi. Per comprendere invece i loro movimenti e le tattiche comportamentali messi in atto dalle otarie orsine del capo per ridurre la probabilità di predazione nella baia di Mossel Bay, abbiamo utilizzato il monitoraggio visivo di 24 ore, effettuato almeno una volta al mese, dalla barca nell’area di Seal Island. Anche se gli squali bianchi sono sempre presenti intorno all’isola i dati ottenuti suggeriscono che la maggior presenza di squali/h si verifica da Maggio a Settembre che coincide con l’ultima fase di svezzamento dei cuccioli delle otarie del capo, cioè quando questi iniziano a foraggiare lontano dall'isola per la prima volta; durante il sunrise (alba) durante il sunset (tramonto) quando il livello di luce ambientale è bassa e soprattutto quando la presenza delle prede in acqua è maggiore. Quindi possiamo affermare che gli squali bianchi a Seal Island prendono delle decisioni che vanno ad ottimizzare la loro probabilità di catturare una preda. I risultati preliminari del nostro studio indicano anche che il numero di gruppi di otarie in partenza dall'isola di notte sono di gran lunga maggiori di quelle che partono durante il giorno, forse questo potrebbe riflettere una diminuzione del rischio di predazione; per beneficiare di una vigilanza condivisa, le otarie tendono in media a formare gruppi di 3-5 o 6-9 individui quando si allontanano dall’isola e questo probabilmente le rende meno vulnerabili e più attente dall’essere predate. Successivamente ritornano all’isola da sole o in piccoli gruppi di 2 o 3 individui. I gruppi più piccoli probabilmente riflettono la difficoltà delle singole otarie a riunirsi in gruppi coordinati all'interno della baia.
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"Contributions from the laboratory of the Marine biological association of San Diego, XIX."
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Etmopterus spinax is a small-sized deep-water lantern shark that occurs in the Eastern Atlantic and the Mediterranean. Differences in depth distribution, densities, size at maturity and fecundity were compared between a population that has suffered high levels of fishing mortality during the last decades (Southern Portugal in the northeast Atlantic) and a population where low fishing pressure below 500 m occurs at present or has occurred in the last decades (Northern Alboran Sea in the western Mediterranean). The density of this species, as derived by experimental bottom trawl survey, off the coast of Southern Portugal, is substantially lower than in the Northern Alboran Sea throughout the entire depth range. The Atlantic population is maturing at smaller sizes than the Mediterranean population and has a lower mean fecundity. Specifically, sizes at maturity for Southern Portugal and the Northern Alboran Sea were, respectively, 25.39 and 28.31 cm TL for males and 30.86 and 34.18 cm TL for females, while mean fecundities for Southern Portugal and the Northern Alboran Sea were, respectively, 9.94 and 11.06 oocytes per mature female. This work demonstrated the possible presence of density-dependent mechanisms in the Southern Portuguese population of E. spinax that has lowered the size at maturity as a possible result of excessive fishing mortality. However, given that this is an aplacentary viviparous shark, where fecundity is dependent on female size, this compensatory mechanism seems to have a limited efficiency.
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The velvet belly lantern shark, Etmopterus spinax (Squaliformes: Etmopteridae), is a small-sized squalid shark commonly found in deep waters off the Portuguese coast, mainly on soft bottoms. In this study, 67 research cruise bottom trawl tows (with 1-hour duration) were carried out at depths that ranged from 84 to 786 m. A total of 396 specimens (192 males and 204 females) were caught, with total lengths and ages ranging, respectively, from 10.2 to 32.9 cm and 0 to 7 years for males and from 9.8 to 41.1 cm and 0 to 10 years for females. Size, age, sex and maturity stages were found to be correlated with depth, with the larger, older and mostly mature specimens occurring predominantly at greater depths. There seems to be a depth-related migration, where the pregnant females migrate from deeper mating grounds to shallower nursery grounds. The sex ratios were relatively similar in the shallower strata, but females dominated at more than 600 m and were exclusive at more than 700 m. Fishing-related mortality may have complex and significant repercussions on this species, given that commercial fisheries are impacting different segments of this population differently.
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Etmopterus spinax is one of the most abundant predators of the upper continental slope off the Algarve (southern Portugal), where it is captured in large quantities in deep-water fisheries. The feeding habits of E. spinax off the Algarve were investigated through the analysis of stomach contents of 376 individuals. Prey composition was described and maturity, sex and size related variations in the diet analysed. The overall diet of E. spinax suggested a fairly generalized benthopelagic foraging behaviour primarily tuned to pelagic macroplankton/microneckton, teleost fish and cephalopods. Sex and maturity related differences in the diet were not significant. Two main ontogenic diet shifts were observed at about 17 and 28 cm total length. Small and medium sized immature sharks had a diet dominated by eurybathic crustaceans, chiefly Meganyctiphanes norvegica and Pasiphaea sivado. Larger individuals consumed more teleosts and cephalopods, in part associated with scavenging as a new feeding strategy. With increasing shark size the diet diversified both in terms of resources exploited and prey size.
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Taxonomic distinction to species level of deep water sharks is complex and often impossible to achieve during fisheries-related studies. The species of the genus Etmopterus are particularly difficult to identify, so they often appear without species assignation as Etmopetrus sp. or spp. in studies, even those focusing on elasmobranchs. During this work, the morphometric traits of two species of Etmopterus, E. spinax and E. pusillus were studied using 27 different morphological measurements, relatively easy to obtain even in the field. These measurements were processed with multivariate analysis in order to find out the most important ones likely to separate the two species. Sexual dimorphism was also assessed using the same techniques, and it was found that it does not occur in these species. The two Etmopterus species presented in this study share the same habitats in the overlapping ranges of distribution and are caught together on the outer shelves and slopes of the north-eastern Atlantic.
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In this paper, the population biology of the velvet belly lanternshark Etmopterus spinax was studied and life-history coefficients determined. Age was estimated from sections of the second dorsal spine and validated by marginal increment analysis. Males attained a maximum age of 8 years while 11 year-old females were found. Several growth models were fitted and compared for both size-at-age and mass-at-age data, showing that even though this is a small-sized species, it has a relatively slow growth rate. This species matures late, specifically at 49.6 and 42.5% of the maximum observed ages for males and females, respectively. It has a low fecundity, with a mean ovarian fecundity of 9.94 oocytes and a mean uterine fecundity of 7.59 embryos per reproductive cycle. This species seems to have a long reproductive cycle, and even though no conclusive data were obtained, a 2-3 year cycle is possible. The estimated coefficients indicate that this species has a vulnerable life cycle, typical of deepwater squalid sharks. Given the high fishing pressures that it is suffering in the north-east Atlantic, this fish may already be facing severe declines or in risk of facing them in the near future. (C) 2008 The Authors Journal compilation (C) 2008 The Fisheries Society of the British Isles
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The deep-sea lantern shark Etmopterus spinax occurs in the northeast Atlantic on or near the bottoms of the outer continental shelves and slopes, and is regularly captured as bycatch in deep-water commercial fisheries. Given the lack of knowledge on the impacts of fisheries on this species, a demographic analysis using age-based Leslie matrices was carried out. Given the uncertainties in the mortality estimates and in the available life history parameters, several different scenarios, some incorporating stochasticity in the life history parameters (using Monte Carlo simulation), were analyzed. If only natural mortality were considered, even after introducing uncertainties in all parameters, the estimated population growth rate (A) suggested an increasing population. However, if fishing mortality from trawl fisheries is considered, the estimates of A either indicated increasing or declining populations. In these latter cases, the uncertainties in the species reproductive cycle seemed to be particularly relevant, as a 2-year reproductive cycle indicated a stable population, while a longer (3-year cycle) indicated a declining population. The estimated matrix elasticities were in general higher for the survivorship parameters of the younger age classes and tended to decrease for the older ages. This highlights the susceptibility of this deep-sea squaloid to increasing fishing mortality, emphasizing that even though this is a small-sized species, it shows population dynamics patterns more typical of the larger-sized and in general more vulnerable species. (C) 2014 Elsevier Ltd. All rights reserved.