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Euphausia superba

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https://www.readbyqxmd.com/read/28915418/purification-identification-and-molecular-mechanism-of-two-dipeptidyl-peptidase-iv-dpp-iv-inhibitory-peptides-from-antarctic-krill-euphausia-superba-protein-hydrolysate
#1
Wei Ji, Chaohua Zhang, Hongwu Ji
Dipeptidyl peptidase IV (DPP-IV) played an important role in blood glucose regulation. Inhibition of DPP-IV may improve glycemic control in diabetics by preventing the rapid breakdown of incretin hormones and prolonging their physiological action. In this study, Antarctic krill (Euphausia superba) protein was hydrolyzed using animal proteolytic enzymes. The hydrolysate was purified sequentially by ultrafiltration, gel filtration chromatography and reversed phase high-performance liquid chromatography (RP-HPLC)...
October 1, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28898957/persistent-organic-pollutants-in-krill-from-the-bellingshausen-south-scotia-and-weddell-seas
#2
Cristóbal J Galbán-Malagón, Gema Hernán, Esteban Abad, Jordi Dachs
Persistent organic pollutants (POPs) reach Antarctica through atmospheric transport, oceanic currents, and to minor extent, by migratory animals. The Southern Ocean is a net sink for many POPs, with a key contribution of the settling fluxes of POPs bound to organic matter (biological pump). However, little is known about POP transfer through the food web in the Southern Ocean and Antarctic waters, where krill is an important ecological node. In this study, we assessed the occurrence of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs) in Antarctic krill (Euphausia superba) from the Bellingshausen, South Scotia and Weddell Seas around the Antarctic Peninsula...
January 1, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/28761090/restricted-regions-of-enhanced-growth-of-antarctic-krill-in-the-circumpolar-southern-ocean
#3
Eugene J Murphy, Sally E Thorpe, Geraint A Tarling, Jonathan L Watkins, Sophie Fielding, Philip Underwood
Food webs in high-latitude oceans are dominated by relatively few species. Future ocean and sea-ice changes affecting the distribution of such species will impact the structure and functioning of whole ecosystems. Antarctic krill (Euphausia superba) is a key species in Southern Ocean food webs, but there is little understanding of the factors influencing its success throughout much of the ocean. The capacity of a habitat to maintain growth will be crucial and here we use an empirical relationship of growth rate to assess seasonal spatial variability...
July 31, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28732330/legacy-persistent-organic-pollutants-including-pbdes-in-the-trophic-web-of-the-ross-sea-antarctica
#4
Simonetta Corsolini, Nicoletta Ademollo, Tania Martellini, Demetrio Randazzo, Marino Vacchi, Alessandra Cincinelli
The ecological features of the Ross Sea trophic web are peculiar and different from other polar food webs, with respect to the use of habitat and species interactions; due to its ecosystem integrity, it is the world's largest Marine Protected Area, established in 2016. Polar organisms are reported to bioaccumulate lipophilic contaminant, viz persistent organic pollutants (POPs). Legacy POPs and flame retardants (polybrominated diphenyl ethers, PBDEs) were studied in key species of the Ross Sea (Euphausia superba, Pleuragramma antarctica) and their predators (Dissostichus mawsoni, Pygoscelis adeliae, Aptenodytes forsteri, Catharacta maccormicki, Leptonychotes weddellii)...
October 2017: Chemosphere
https://www.readbyqxmd.com/read/28685164/competition-induced-starvation-drives-large-scale-population-cycles-in-antarctic-krill
#5
Alexey B Ryabov, André M de Roos, Bettina Meyer, So Kawaguchi, Bernd Blasius
Antarctic krill (Euphausia superba) - one of the most abundant animal species on Earth - exhibits a 5-6 year population cycle, with oscillations in biomass exceeding one order of magnitude. Previous studies have postulated that the krill cycle is induced by periodic climatological factors, but these postulated drivers neither show consistent agreement, nor are they supported by quantitative models. Here, using data analysis complemented with modeling of krill ontogeny and population dynamics, we identify intraspecific competition for food as the main driver of the krill cycle, while external climatological factors possibly modulate its phase and synchronization over large scales...
July 2017: Nature ecology & evolution
https://www.readbyqxmd.com/read/28490058/a-cold-active-transglutaminase-from-antarctic-krill-euphausia-superba-purification-characterization-and-application-in-the-modification-of-cold-set-gelatin-gel
#6
Yi Zhang, Shudong He, Benjamin K Simpson
Transglutaminase (TGase), EC 2.3.2.13, 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
https://www.readbyqxmd.com/read/28362847/sexual-and-individual-foraging-segregation-in-gentoo-penguins-pygoscelis-papua-from-the-southern-ocean-during-an-abnormal-winter
#7
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
https://www.readbyqxmd.com/read/28249036/humpback-whale-super-groups-a-novel-low-latitude-feeding-behaviour-of-southern-hemisphere-humpback-whales-megaptera-novaeangliae-in-the-benguela-upwelling-system
#8
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
https://www.readbyqxmd.com/read/28237087/e-configuration-structures-of-epa-and-dha-derived-from-euphausia-superba-and-their-significant-inhibitive-effects-on-growth-of-human-cancer-cell-lines-in-vitro
#9
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
https://www.readbyqxmd.com/read/28225825/validation-of-band-counts-in-eyestalks-for-the-determination-of-age-of-antarctic-krill-euphausia-superba
#10
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
https://www.readbyqxmd.com/read/28187156/krilldb-a-de-novo-transcriptome-database-for-the-antarctic-krill-euphausia-superba
#11
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
https://www.readbyqxmd.com/read/27812046/diversity-and-function-of-the-antarctic-krill-microorganisms-from-euphausia-superba
#12
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
https://www.readbyqxmd.com/read/27622510/quantifying-the-escape-mortality-of-trawl-caught-antarctic-krill-euphausia-superba
#13
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
https://www.readbyqxmd.com/read/27567712/differing-foraging-strategies-influence-mercury-hg-exposure-in-an-antarctic-penguin-community
#14
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
https://www.readbyqxmd.com/read/27533327/at-sea-distribution-and-prey-selection-of-antarctic-petrels-and-commercial-krill-fisheries
#15
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
https://www.readbyqxmd.com/read/27306583/southern-right-whale-eubalaena-australis-reproductive-success-is-influenced-by-krill-euphausia-superba-density-and-climate
#16
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
https://www.readbyqxmd.com/read/27184514/-the-therapeutic-effects-of-dietary-krill-oil-euphausia-superba-supplementation-on-oxidative-stress-and-dna-damages-markers-in-cafeteria-diet-overfed-rats
#17
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
https://www.readbyqxmd.com/read/27157882/the-opsin-repertoire-of-the-antarctic-krill-euphausia-superba
#18
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
https://www.readbyqxmd.com/read/26456758/phosphorylated-peptides-from-antarctic-krill-euphausia-superba-prevent-estrogen-deficiency-induced-osteoporosis-by-inhibiting-bone-resorption-in-ovariectomized-rats
#19
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
https://www.readbyqxmd.com/read/26439671/assessing-the-structure-and-temporal-dynamics-of-seabird-communities-the-challenge-of-capturing-marine-ecosystem-complexity
#20
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
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