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Euphausia superba

Yi Zhang, Shudong He, Benjamin K Simpson
Transglutaminase (TGase), EC, was purified from whole Antarctic krill (Euphausia superba) using ammonium sulfate fractionation and DEAE-Sephacel chromatography. The purified enzyme had specific activity, purification fold and yield of 53.518U/mg, 10.272 and 10.992%, respectively. The molecular weight of the purified Antarctic krill TGase was estimated to be 78kDa using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal pH and temperature for the activity of the purified TGase were pH 8...
October 1, 2017: Food Chemistry
José C Xavier, Philip N Trathan, Filipe R Ceia, Geraint A Tarling, Stacey Adlard, Derren Fox, Ewan W J Edwards, Rui P Vieira, Renata Medeiros, Claude De Broyer, Yves Cherel
Knowledge about sexual segregation and gender-specific, or indeed individual specialization, in marine organisms has improved considerably in the past decade. In this context, we tested the "Intersexual Competition Hypothesis" for penguins by investigating the feeding ecology of Gentoo penguins during their austral winter non-breeding season. We considered this during unusual environmental conditions (i.e. the year 2009 had observations of high sea surface and air temperatures) in comparison with the long term average at Bird Island, South Georgia...
2017: PloS One
Ken P Findlay, S Mduduzi Seakamela, Michael A Meÿer, Stephen P Kirkman, Jaco Barendse, David E Cade, David Hurwitz, Amy S Kennedy, Pieter G H Kotze, Steven A McCue, Meredith Thornton, O Alejandra Vargas-Fonseca, Christopher G Wilke
Southern Hemisphere humpback whales (Megaptera novaeangliae) generally undertake annual migrations from polar summer feeding grounds to winter calving and nursery grounds in subtropical and tropical coastal waters. Evidence for such migrations arises from seasonality of historic whaling catches by latitude, Discovery and natural mark returns, and results of satellite tagging studies. Feeding is generally believed to be limited to the southern polar region, where Antarctic krill (Euphausia superba) has been identified as the primary prey item...
2017: PloS One
Weilong Zheng, Xudong Wang, Wenjing Cao, Bowen Yang, Ying Mu, Yuesheng Dong, Zhilong Xiu
Many bioactive components such as poly-unsaturated fatty acids (e.g. EPA and DHA), phospholipids and astaxanthin are known in Antarctic krill (Euphausia superba) oil. The krill DHA and EPA are generally considered to be similar to natural ones. However, two chemical compounds which were separated from Antarctic krill oil and identified as EPA and DHA by HRESIMS and NMR acted much more effective inhibitive activities on growth of several cell lines (U937, K562, SMMC-7721, PC-3, MDA-MB-231, HL60 and MCF-7) than those from sturgeon liver and commercial fish oil...
February 2017: Prostaglandins, Leukotrienes, and Essential Fatty Acids
Raouf Kilada, Christian S Reiss, So Kawaguchi, Robert A King, Tsuyoshi Matsuda, Taro Ichii
Using known-age Antarctic krill (Euphausia superba) grown from eggs hatched at two different laboratories, we validate the annual pattern of bands deposited in the eyestalks of krill and determine the absolute age of these animals. Ages two through five years were validated, and these animals ranged from 37.1 to 62.6 mm in total length. The band counts in these individuals were either identical to their absolute ages, or only failed to agree by a few months, which demonstrates the accuracy of this method. Precision and bias were estimated graphically using Chang's index (Coefficient of Variation = 5...
2017: PloS One
Gabriele Sales, Bruce E Deagle, Enrica Calura, Paolo Martini, Alberto Biscontin, Cristiano De Pittà, So Kawaguchi, Chiara Romualdi, Bettina Meyer, Rodolfo Costa, Simon Jarman
Antarctic krill (Euphausia superba) is a key species in the Southern Ocean with an estimated biomass between 100 and 500 million tonnes. Changes in krill population viability would have catastrophic effect on the Antarctic ecosystem. One looming threat due to elevated levels of anthropogenic atmospheric carbon dioxide (CO2) is ocean acidification (lowering of sea water pH by CO2 dissolving into the oceans). The genetics of Antarctic krill has long been of scientific interest for both for the analysis of population structure and analysis of functional genetics...
2017: PloS One
Xiaoqiu Cui, Guoliang Zhu, Haishan Liu, Guoliang Jiang, Yi Wang, Weiming Zhu
The diversity and ecological function of microorganisms associated with Euphausia superba, still remain unknown. This study identified 75 microbial isolates from E. superba, that is 42 fungi and 33 bacteria including eight actinobacteria. And all the isolates showed NaF tolerance in conformity with the nature of the fluoride krill. The maximum concentration was 10%, 3% and 0.5% NaF for actinobacteria, bacteria and fungi, respectively. The results demonstrated that 82.4% bacteria, 81.3% actinobacteria and 12...
November 4, 2016: Scientific Reports
Bjørn A Krafft, Ludvig A Krag, Arill Engås, Sigve Nordrum, Inge Bruheim, Bent Herrmann
Antarctic krill (Euphausia superba) is an abundant fishery resource, the harvest levels of which are expected to increase. However, many of the length classes of krill can escape through commonly used commercial trawl mesh sizes. A vital component of the overall management of a fishery is to estimate the total fishing mortality and quantify the mortality rate of individuals that escape from fishing gear. The methods for determining fishing mortality in krill are still poorly developed. We used a covered codend sampling technique followed by onboard observations made in holding tanks to monitor mortality rates of escaped krill...
2016: PloS One
Michael J Polito, Rebecka L Brasso, Wayne Z Trivelpiece, Nina Karnovsky, William P Patterson, Steven D Emslie
Seabirds are ideal model organisms to track mercury (Hg) through marine food webs as they are long-lived, broadly distributed, and are susceptible to biomagnification due to foraging at relatively high trophic levels. However, using these species as biomonitors requires a solid understanding of the degree of species, sexual and age-specific variation in foraging behaviors which act to mediate their dietary exposure to Hg. We combined stomach content analysis along with Hg and stable isotope analyses of blood, feathers and common prey items to help explain inter and intra-specific patterns of dietary Hg exposure across three sympatric Pygoscelis penguin species commonly used as biomonitors of Hg availability in the Antarctic marine ecosystem...
November 2016: Environmental Pollution
Sébastien Descamps, Arnaud Tarroux, Yves Cherel, Karine Delord, Olaf Rune Godø, Akiko Kato, Bjørn A Krafft, Svein-Håkon Lorentsen, Yan Ropert-Coudert, Georg Skaret, Øystein Varpe
Commercial fisheries may impact marine ecosystems and affect populations of predators like seabirds. In the Southern Ocean, there is an extensive fishery for Antarctic krill Euphausia superba that is projected to increase further. Comparing distribution and prey selection of fishing operations versus predators is needed to predict fishery-related impacts on krill-dependent predators. In this context, it is important to consider not only predators breeding near the fishing grounds but also the ones breeding far away and that disperse during the non-breeding season where they may interact with fisheries...
2016: PloS One
Elisa Seyboth, Karina R Groch, Luciano Dalla Rosa, Keith Reid, Paulo A C Flores, Eduardo R Secchi
The reproductive success of southern right whale (Eubalaena australis) depends on body condition and, therefore, on foraging success. This, in turn, might be affected by climatically driven change in the abundance of the species main prey, krill (Euphausia superba), on the feeding grounds. Annual data on southern right whale number of calves were obtained from aerial surveys carried out between 1997 and 2013 in southern Brazil, where the species concentrate during their breeding season. The number of calves recorded each year varied from 7 to 43 ( = 21...
2016: Scientific Reports
Z Mellouk, M Agustina, M Ramirez, K Pena, J Arivalo
AIM: To evaluate the therapeutic effects of dietary krill oil supplementation in modulation of oxidative stress components and DNA oxidative damages marker in cafeteria diet-overfed-rats. MATERIAL AND METHODS: Eighteen aging male Wistar rats were divided into three groups of six each and were exposed for the ensuing 8 weeks to one of the diets: control group (TS) which was submitted to standard chow (330kcal/100g), containing 24% of proteins, 5% of lipids and 70% of carbohydrates...
June 2016: Annales de Cardiologie et D'angéiologie
Alberto Biscontin, Elena Frigato, Gabriele Sales, Gabriella M Mazzotta, Mathias Teschke, Cristiano De Pittà, Simon Jarman, Bettina Meyer, Rodolfo Costa, Cristiano Bertolucci
The Antarctic krill Euphausia superba experiences almost all marine photic environments throughout its life cycle. Antarctic krill eggs hatch in the aphotic zone up to 1000m depth and larvae develop on their way to the ocean surface (development ascent) and are exposed to different quality (wavelength) and quantity (irradiance) of light. Adults show a daily vertical migration pattern, moving downward during the day and upward during the night within the top 200m of the water column. Seawater acts as a potent chromatic filter and animals have evolved different opsin photopigments to perceive photons of specific wavelengths...
October 2016: Marine Genomics
Guanghua Xia, Yanlei Zhao, Zhe Yu, Yingying Tian, Yiming Wang, Shanshan Wang, Jingfeng Wang, Changhu Xue
In the current study, we investigated the improvement of phosphorylated peptides from Antarctic krill Euphausia superba (PP-AKP) on osteoporosis in ovariectomized rats. PP-AKP was supplemented to ovariectomized Sprague-Dawley rats for 90 days. The results showed that PP-AKP treatment remarkably prevented the reduction of bone mass and improved cancellous bone structure and biochemical properties. PP-AKP also significantly decreased serum contents of tartrate-resistant acid phosphatase (TRACP), cathepsin K (Cath-k), matrix metalloproteinases-9 (MMP-9), deoxypyridinoline (DPD), C-terminal telopeptide of collagen I (CTX-1), Ca, and P...
November 4, 2015: Journal of Agricultural and Food Chemistry
Rocío Moreno, Gabriele Stowasser, Rona A R McGill, Stuart Bearhop, Richard A Phillips
Understanding interspecific interactions, and the influences of anthropogenic disturbance and environmental change on communities, are key challenges in ecology. Despite the pressing need to understand these fundamental drivers of community structure and dynamics, only 17% of ecological studies conducted over the past three decades have been at the community level. Here, we assess the trophic structure of the procellariiform community breeding at South Georgia, to identify the factors that determine foraging niches and possible temporal changes...
January 2016: Journal of Animal Ecology
Bruce E Deagle, Cassandra Faux, So Kawaguchi, Bettina Meyer, Simon N Jarman
Antarctic krill (Euphausia superba; hereafter krill) are an incredibly abundant pelagic crustacean which has a wide, but patchy, distribution in the Southern Ocean. Several studies have examined the potential for population genetic structuring in krill, but DNA-based analyses have focused on a limited number of markers and have covered only part of their circum-Antarctic range. We used mitochondrial DNA and restriction site-associated DNA sequencing (RAD-seq) to investigate genetic differences between krill from five sites, including two from East Antarctica...
October 2015: Molecular Ecology
Yanchao Wang, Ruo Wang, Yaoguang Chang, Ying Gao, Zhaojie Li, Changhu Xue
Protein isolate was prepared from defatted Antarctic krill (Euphausia superba) byproducts by 0.1 M NaOH extraction. Maximum yield of krill protein isolate reached 28.66% by precipitation at pH 4.6. Krill protein isolate demonstrated its excellent nutritional values through amino acid composition and in vitro digestibility. Thermal transition of krill protein isolate was determined by differential scanning calorimetry measurement. Extrapolated values of glass transition temperature (Tg) and denaturation temperature (Td) of krill protein isolate were 33...
December 1, 2015: Food Chemistry
Corrie Curtice, David W Johnston, Hugh Ducklow, Nick Gales, Patrick N Halpin, Ari S Friedlaender
BACKGROUND: A population of humpback whales (Megaptera novaeangliae) spends the austral summer feeding on Antarctic krill (Euphausia superba) along the Western Antarctic Peninsula (WAP). These whales acquire their annual energetic needs during an episodic feeding season in high latitude waters that must sustain long-distance migration and fasting on low-latitude breeding grounds. Antarctic krill are broadly distributed along the continental shelf and nearshore waters during the spring and early summer, and move closer to land during late summer and fall, where they overwinter under the protective and nutritional cover of sea ice...
2015: Movement Ecology
Maria João F Martins, Asuncion Lago-Leston, Antonio Anjos, Carlos M Duarte, Susana Agusti, Ester A Serrão, Gareth A Pearson
Euphausia superba is a keystone species in Antarctic food webs. However, the continued decrease in stock density raises concerns over the resilience and adaptive potential of krill to withstand the current rate of environmental change. We undertook a transcriptome-scale approach (454 pyrosequencing) as a baseline for future studies addressing the physiological response of krill to short-term food shortage and natural UV-B stress. The final assembly resulted in a total of 26,415 contigs, 39.8% of which were putatively annotated...
October 2015: Marine Genomics
Kévin Cascella, Didier Jollivet, Claire Papot, Nelly Léger, Erwan Corre, Juliette Ravaux, Melody S Clark, Jean-Yves Toullec
BACKGROUND: A comparative thermal tolerance study was undertaken on two sister species of Euphausiids (Antarctic krills) Euphausia superba and Euphausia crystallorophias. Both are essential components of the Southern Ocean ecosystem, but occupy distinct environmental geographical locations with slightly different temperature regimes. They therefore provide a useful model system for the investigation of adaptations to thermal tolerance. METHODOLOGY/PRINCIPAL FINDING: Initial CTmax studies showed that E...
2015: PloS One
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