Enzymatic hydrolysis,isolation,and purification might make a great deal of difference in antioxidant activity and antigenicity of peptide components.This study aimed to isolate and purify antioxidant peptide component...Enzymatic hydrolysis,isolation,and purification might make a great deal of difference in antioxidant activity and antigenicity of peptide components.This study aimed to isolate and purify antioxidant peptide components from Antarctic krill and evaluate their allergenicity of them.Electron paramagnetic resonance(EPR)spectroscopy results indicated 3-10 kDa Antarctic krill hydrolysates(AKHs)had higher DPPH and·OH radical scavenging rates.And the second component(N2-2)purified 3-10 kDa hydrolysate showed better ability to scavenge DPPH and·OH radicals(P<0.05),which were(47.43±2.18)%and(34.33±1.25)%,respectively.Additionally,indirect-ELISA results revealed that N2-1 had a weaker ability to bind specific IgE and that N2-2 had a lower binding capability to specific IgG1(P<0.05).And N2-2 had a higher EC50 value of(5.29±0.95)ng/mL(P<0.05)in cell degranulation assay,which was about 13.80 times that of Antarctic krill.Therefore,N2-2 might be the potential source of the antioxidant peptides with lower allergenicity.展开更多
The objective of this study was to determine the quality changes and shelf life of ready-to-eat roasted Antarctic krill,either untreated(CT)or treated with sodium diacetate(SD)or sodium diacetate and a deoxidizer(SDD)...The objective of this study was to determine the quality changes and shelf life of ready-to-eat roasted Antarctic krill,either untreated(CT)or treated with sodium diacetate(SD)or sodium diacetate and a deoxidizer(SDD),during storage at room temperature(25℃)by using sensory,physiochemical,and microbial assessment.Additionally,fluoride accumulation in this food product was used to evaluate its safety.Analysis showed that the addition of SD and SDD resulted in better sensory scores compared of that of CT samples(P<0.05).Accordingly,microorganism growth and total basic nitrogen(TVB-N)were maintained at a low level for the duration of storage with SD and SDD treatments.The total viable counts of SD and SDD reached(4.58±0.08)log(CFU g^(−1))and(4.20±0.11)log(CFUg^(−1)),respectively.The mold was found after 6 and 18 days for SD and SDD treatment,and the numbers reached 5.2×10^(6) and 8.5×10^(4) respectively at the end of shelf life.The TVB-N values from CT continuously increased during the whole storage.While TVB-N values from SD and SDD remained significantly less change(P<0.05)during the early 20 days of the storage,and the values reached(12.11±0.07)mg(100 g)^(−1) and(10.88±0.15)mg(100 g)^(−1) on day 33 and day 70,respectively.Importantly,SDD treatment effectively minimized the oxidation values and retained the color of ready-to-eat roasted Antarctic krill.Our results showed that the shelf life of ready-to-eat roasted Antarctic krill treated with SDD was extended by up to 52 days.Additionally,rats fed ready-to-eat roasted Antarctic krill showed accumulation of fluoride exclusively in the thighbone.The accumulation of fluoride residues in the thighbone showed concentration-dependent.The concentrations of fluoride residues in rats were(1760.03±38.21),(2371.52±42.15)mgkg^(−1) and(3615.44±30.53)mgkg^(−1),which were less than sodium fluoride feeding group(4621.01±28.67)mgkg^(−1).The results suggested that the SD and SDD treatments led to better quality and shelf life extension of ready-to-eat roasted Antarctic krill during storage at room temperature(25℃).Therefore,the ready-to-eat roasted Antarctic krill can be of great interest to the seafood industry.展开更多
Fog Computing(FC)provides processing and storage resources at the edge of the Internet of Things(IoT).By doing so,FC can help reduce latency and improve reliability of IoT networks.The energy consumption of servers an...Fog Computing(FC)provides processing and storage resources at the edge of the Internet of Things(IoT).By doing so,FC can help reduce latency and improve reliability of IoT networks.The energy consumption of servers and computing resources is one of the factors that directly affect conservation costs in fog environments.Energy consumption can be reduced by efficacious scheduling methods so that tasks are offloaded on the best possible resources.To deal with this problem,a binary model based on the combination of the Krill Herd Algorithm(KHA)and the Artificial Hummingbird Algorithm(AHA)is introduced as Binary KHA-AHA(BAHA-KHA).KHA is used to improve AHA.Also,the BAHA-KHA local optimal problem for task scheduling in FC environments is solved using the dynamic voltage and frequency scaling(DVFS)method.The Heterogeneous Earliest Finish Time(HEFT)method is used to discover the order of task flow execution.The goal of the BAHA-KHA model is to minimize the number of resources,the communication between dependent tasks,and reduce energy consumption.In this paper,the FC environment is considered to address the workflow scheduling issue to reduce energy consumption and minimize makespan on fog resources.The results were tested on five different workflows(Montage,CyberShake,LIGO,SIPHT,and Epigenomics).The evaluations show that the BAHA-KHA model has the best performance in comparison with the AHA,KHA,PSO and GA algorithms.The BAHA-KHA model has reduced the makespan rate by about 18%and the energy consumption by about 24%in comparison with GA.This is a preview of subscription content,log in via an institution to check access.展开更多
This work conducted a four-week metabolism test on rats to study the digestion and absorption characteristics of five protein-based krill products prepared from Antarctic krill as raw material.It aimed to provide theo...This work conducted a four-week metabolism test on rats to study the digestion and absorption characteristics of five protein-based krill products prepared from Antarctic krill as raw material.It aimed to provide theoretical support for the effective use of Antarctic krill protein and the development of novel protein resources.The results showed that the weight gain and true digestibility of the rats fed with krill meat,surimi and ordinary krill powder were significantly higher(P<0.05)than those of the rats fed with traditional casein.Compared to casein,proteins from the five Antarctic krill products were found to significantly improve the net protein utilization(P<0.05),and reduce the total cholesterol and triglycerides in the serum of rats(P<0.05).In summary,the Antarctic krill protein-based products with high nutritional values can be used as a potential novel protein resource in the food industry.展开更多
The different forms fluoine in different parts of molting process of krill was analyzed by culture of Antarctic krill (Euphausia superba). The results shaw that fluorine amount in cuticle is up to 90% of total in the ...The different forms fluoine in different parts of molting process of krill was analyzed by culture of Antarctic krill (Euphausia superba). The results shaw that fluorine amount in cuticle is up to 90% of total in the krill. During the krill molting process, the fluorine content in cuticle and muscle varies alternatively. This is to say, the fluorine content in new cuticle and muscle is much lower after molted, the fluorine in krill comes from seawater by biological absorption of the krill, and the fluorine absorbed by krill lost with the old cuticle at the end stage of molting process. Meanwhile, the new molting process starts again. The evidence is proved by the change of different forms fluorine content in cuticle and muscle during krill’s molting process. At last the author proposes the fluorine enriching process model of Antarctic krill.展开更多
Phospholipids are one of the major bioactive ingredients of Antarctic krill Euphausea superba. A feasible and effective extraction method of Antarctic krill oil was investigated and modified by orthogonal test which t...Phospholipids are one of the major bioactive ingredients of Antarctic krill Euphausea superba. A feasible and effective extraction method of Antarctic krill oil was investigated and modified by orthogonal test which the ratio of solid to liquid was 1:2.5, extraction time was 5 min, ratio of ethyl acetate (EA) and n-butanol (BuOH) was 1:1. With this method, the extract of krill oil has a higher phospholipids content of 27.7% - 42.3%, together with total oil yields of 4.15% - 6.18%.展开更多
Antarctic krill(Euphausia superba)oil has been gaining increasing attention due to its nutritional and functional potentials.Krill oil usually contains a high concentration(about 50%)of phospholipids(AKOP)rich in DHA ...Antarctic krill(Euphausia superba)oil has been gaining increasing attention due to its nutritional and functional potentials.Krill oil usually contains a high concentration(about 50%)of phospholipids(AKOP)rich in DHA and EPA accompanied with 30%–40%triacylglycerols.Phospholipids can be made into liposomes without emulsifiers due to its amphiphilic characteristics.However,the absorption kinetics of AKOP liposome in vivo is not clear,which restrict the molecular mechanism analysis related to its distinct bioactivities.The lipid analysis in serum,small intestinal content and wall was carried out after oral administration of AKOP liposome to illustrate its absorption kinetics in blood and the digestive tract of healthy mice by single gavage.The major type of the obtained AKOP was phosphatidylcholine,and the total contents of the DHA and EPA were 29.31%.AKOP liposome was almost completely digested in the small intestine in 1 h and the hydrolysis products could be quickly absorbed by intestinal enterocytes.The DHA in serum peaked at 2 h after administration of AKOP liposome.AKOP liposome could be quickly digested and absorbed in vivo.The obtained results might provide a scientific basis for the molecular mechanism analysis related to distinct bioactivities of Antarctic krill oil phospholipid.展开更多
The aim of the study is to investigate the existing form and the partitioning pattern of fluoride in krill (Euphusia superba) by analysing the fluoride and other elements in various part of krill, primarily to approac...The aim of the study is to investigate the existing form and the partitioning pattern of fluoride in krill (Euphusia superba) by analysing the fluoride and other elements in various part of krill, primarily to approach the potential concentrating mechanism and the effect of fluoride in krill on the geochemical characteristics of fluoride in the Antarctic ecoenvironment. The results of the study show that the amount of flouride in various part of krill has a considerable difference. Most of fluoride is concentrated in the carapace, up to 4028μg/g, and the head and legs, respectively 2724μg/g and 2828μg/g. The muscle contains the least flouride with amount of 226μg/g. The amount of fluoride in whole freeze-dried krill is averagely 1232μg/g, which indicates that the functional position of fluoride in krill is mainly located at the crust. Only a few of fluoride is found in the chitin of the carapaces (200μg/g), which exhibits that fluoride in the carapaces exists mostly in the form of the展开更多
Water-washing removes fluoride from Antarctic krill but produces large volumes of wash water containing water-soluble proteins and fluoride. The freeze concentration method was tested to determine if it could be used ...Water-washing removes fluoride from Antarctic krill but produces large volumes of wash water containing water-soluble proteins and fluoride. The freeze concentration method was tested to determine if it could be used to recover water-soluble proteins while leaving the fluoride in solution. After freezing and thawing the wash water, protein and fluoride contents of the thawed fractions were determined to explore the melting regularity of components in the wash water. The highest concentration factors of protein and fluoride were obtained after 80 min of thawing, such as 1.48 ± 0.06 and 1.35 ± 0.04 times, respectively. The free amino-nitrogen(FAN) content and sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern results revealed that the highest concentrations of all ingredients were obtained after 80 min of the process. The degree of hydrolysis of all fractions from the thawing process fluctuated in a narrow range around 12% during the entire process, indicating that the thawing order did not change with various proteins or time during the entire thawing course. These results demonstrate that the freeze concentration method can be used to concentrate protein solutions, even those with fluoride. It was concluded that condensation was achieved and no ingredient could be separated, regardless of fluoride, amino acids, or different proteins in the water.展开更多
Each type of fishery has its own characteristic behavior, and understanding this condition is an important part of devel- oping and managing fishing operations comprehensively. Based on the random walk model, the rela...Each type of fishery has its own characteristic behavior, and understanding this condition is an important part of devel- oping and managing fishing operations comprehensively. Based on the random walk model, the relationship between distance and frequency distribution of adjacent fishing positions was analyzed by the Commission for Conservation of Antarctic Marine Living Resources (CCAMLR) Subareas 48.1, 48.2, and 48.3. The frequency of distances between consecutive hauls demonstrated a heavy- tailed distribution, which could be used to estimate the value of parameter μ in the power function F(l)~ l μ of a random walk model to determine the type of random walk patterns that characterize Chinese krill fishery. Results indicated that the fishing pattern of the Chinese krill fishery is consistent with the Lévy random walk model, with which the step-length is applied to analyze the walking pattern. When a defined walk in a space of dimension is greater than one, the steps made are in isotropic random directions. Fur- thermore, a strong and positive correlation between fishing behavior (using the parameter μ as an indicator) and catch per unit effort of the Chinese krill fishery was observed.展开更多
Antarctic krill is thought to undergo an annual cycle of biological processes to cope with seasonal changes in their environment. The question of whether, and to what degree, seasonal environmental parameters such as ...Antarctic krill is thought to undergo an annual cycle of biological processes to cope with seasonal changes in their environment. The question of whether, and to what degree, seasonal environmental parameters such as photoperiod, food availability and temperature govern metabolism in krill is not clear. In this long-term laboratory study, respiration rates were determined in krill incubated under simulated natural light cycle or total darkness, subjected to fed or starved conditions and on krill kept at different temperatures (-1°C, 1°C and 3°C). There was a strong and significant increasing trend of respiration rates with month in all experimental treatments. In August (late winter), the mean respiration rates ranged between 0.22 - 0.35 μL O2 mg.DW-1.hr-1 for krill in both simulated seasonal light and complete darkness, and 0.25 - 0.26 μL O2 mg.DW-1.hr-1 for both fed and starved krill. Mean maximal respiration rates were recorded in October and December for all light and feeding treatments (0.46 - 0.56 μL O2 mg.DW-1.hr-1). Mean respiration rates for krill in the temperature treatments ranged between 0.24 - 0.30 μL O2 mg.DW-1.hr-1 in September reaching mean maximal rates in November and February (0.60 - 0.71 μL O2 mg.DW-1.hr-1). The covariate total length of krill was found to be non-significant and there was generally no significant interaction of experimental treatment with month and only for photoperiod comparison was the treatment main effect significant. The dark treatment gave higher respiration rates, and this needs careful interpretation. Results here suggest that, although light, food availability and temperature significantly affect metabolic rates,展开更多
Antarctic krill (Euphausia superba) were collected from the Prydz Bay region during the austral summer of 1999/2000. The sample-collection was made at 15 sites in 3 longitudinal transects. Although krill were encounte...Antarctic krill (Euphausia superba) were collected from the Prydz Bay region during the austral summer of 1999/2000. The sample-collection was made at 15 sites in 3 longitudinal transects. Although krill were encountered at 14 sites, the abundance was comparatively low in general. The main component of the krill population was of post-larval stages. The mean numerical and weight density of krill integrated for all sampling stations in the survey area were 16.17 ind.1000 m-3 and 12.02 g 1000 m-3 , respectively. In the survey area, stations with larger krill density are mainly located in the slope zone, except that the largest sample was collected in the open sea zone. No krill occurred in the only station of the shelf zone during our investigation. Krill collected from the slope zone were under better growth condition than those from the open sea zone, but when the survey area is considered as a whole, the growth condition is normal. The results of the comprehensive analysis of the environmental factors show that the three large sample stations seem to be related with the cold water mass at 75 m depth and the confluence area between the high and low Chl a centers at the depth of 25 m.展开更多
Lipase from Antarctic krill,with a molecular weight of 71.27kDa,was purified with ammonium sulfate precipitation and a series of chromatographic separations over ion exchange(DEAE)and gel filtration columns(Sephacryl ...Lipase from Antarctic krill,with a molecular weight of 71.27kDa,was purified with ammonium sulfate precipitation and a series of chromatographic separations over ion exchange(DEAE)and gel filtration columns(Sephacryl S-100),resulting in 5.2%recovery with a 22.4-fold purification ratio.The optimal pH and temperature for enzyme activity were 8.0 and 45℃,respectively.Purified lipase had Km and Vmax values of 3.27mmolL−1 and 2.4Umg−1,respectively,using p-nitrophenyl laurate as the substrate.Lipase activity was enhanced by adding Ca2+and Mg2+ions in the concentration ranges of 0–0.5mmolL−1 and 0–0.3mmolL−1,respectively,while the activity was inhibited by a further increase in these ion concentrations.Fe3+and Cu2+ions showed obvious inhibitory effects on enzyme activity,and the inhibition rates were 71.8%and 53.3%when the ion concentrations were 0.5mmolL−1.展开更多
Antarctic krill is the key species of ecological system in the Amundsen Sea.At present,the suitable distribution is unobtainable by scientifi c surveys or data from the fi shery.In this paper,the maximum entropy algor...Antarctic krill is the key species of ecological system in the Amundsen Sea.At present,the suitable distribution is unobtainable by scientifi c surveys or data from the fi shery.In this paper,the maximum entropy algorithm(Maxent)was used to obtain the potential distribution of adult Antarctic krill in order to provide useful information and reasonable reference for the policy on protecting potential krill habitats around the Amundsen Sea.Occurrence points and 17 environmental variables were used to simulate the distributions.Results show that the high and moderate suitable habitats lie between 65°S and 72°S in the Amundsen Sea.The high suitable habitat accounts for 8.1%of the total area of the Amundsen Sea.The sea ice persistence(ICE),total phytoplankton(PHYC),and the minimum value of dissolved iron(Fe_min)are the three dominant contributors to the model.Results from the response curves show that Antarctic krill preferred habitats with ICE of 0.42-0.93,PHYC of 2.48-2.77 mmol/m^(3) and Fe_min of(7.10×10^(-5))-(9.45×10^(-5))mmol/m 3.Positive trends existed in the PHYC of the high and moderate suitable habitat,and a positive trend existed in the Fe_min of moderate suitable habitat.However,the probability of presence of Antarctic krill will decrease if the increase of the PHYC and Fe_min continues.展开更多
The cause of the concentration of fluoride in Antaractic krill is studied by the analysis of the characteristics of fluoride change in the cuticle of the krill before and after moulting. Associated with other related ...The cause of the concentration of fluoride in Antaractic krill is studied by the analysis of the characteristics of fluoride change in the cuticle of the krill before and after moulting. Associated with other related information, the source and accumulating mechanism of fluoride in krill are also disscussed. Results show that as an inorganic medium the cuticle of krill has the second concentrating function and action to fluoride after moulting, which has nothing to do with the biological action of the krill. The fluoride is concentrated from seawater, which is prosecuted mainly in the form of ion exchange.展开更多
Age groups of Antarctic krill ( Euphausia superba Dana) in the Prydz Bay region were studied by distribution mixture analysis based on length/frequency data collected by R/V Jidi during the 1989/1990 and 1990/1991 aus...Age groups of Antarctic krill ( Euphausia superba Dana) in the Prydz Bay region were studied by distribution mixture analysis based on length/frequency data collected by R/V Jidi during the 1989/1990 and 1990/1991 austral summer. Five age groups were determined, i.e. 1 +, 2 +, 3 +, 4 +, and 5 + , or six age groups in all, if the 0 + larvae were included. The mean body length of 1 + to 5 + age groups was 25.70 mm, 40.47 mm, 45.52 mm, 50.52 mm and 54.52 mm respectively. Supposing the difference in body length between successive age groups is a reflection of the yearly growth, the maximum growth rate occurred during the period from 1 + juveniles to 2 + subadults (14.77 mm/a). From 2 + subadults to 3 + adults the growth rate dropped steeply (5.05 mm/a) because at this stage, increase of body length was substituted, to a great extent, by the growth of sexual products. From 3 + onwards the growth rate was maintained at a relatively low level and decreased slowly with age. The relative abundance of age groups 1 + and 2 +, in our sample must be much lower than that in the real population owing to both the large mesh size we used and the distribution difference between juveniles and adults. If we left aside 1 + and 2 + age groups and just looked at the relative abundance of adults, we found that age group 3 + dominated the adult population and that the relative abundance decreased sharply with increasing age. If this situation is normal, one can expect an extremely high mortality rate in adults, 82.6% from 3 + to 4 + and 94.0% from 4 + to 5 +. This is reasonably expectable for the Prydz Bay region.展开更多
As one of the most common and dominant species in the Southern Ocean, Antarctic krill(Euphausia superba)play a significant role in food web structure and the process of energy flow. The diet of Antarctic krill in the ...As one of the most common and dominant species in the Southern Ocean, Antarctic krill(Euphausia superba)play a significant role in food web structure and the process of energy flow. The diet of Antarctic krill in the Prydz Bay during austral summer of 2012/2013 was investigated and the ontogenetic shift in krill diet was evaluated using the stable isotope method. The nitrogen stable isotope values(δ^(15) N) of adults((2.78±0.58)‰) were much higher than those of juveniles((1.69±0.70)‰), whereas the carbon stable isotope values(δ^(13) C) of adults(–(28.26±1.08)‰) were slightly lower than those of juveniles(–(27.48±1.35)‰). Particulate organic matter(POM)from 0, 25, and 50 m depth combined(0/25/50 m) represented phytoplankton food items. The results showed that phytoplankton food items in surface water and mesozooplankton were two essential food items for Antarctic krill in the Prydz Bay during summer. POM(0/25/50 m) contributes 56%–69% and 26%–34% to the diet of juvenile and adult krill, respectively, whereas mesozooplankton composes 13%–34% and 58%–71% of the diet of juvenile and adult krill, respectively. Thus, an ontogenetic diet shift from POM(0/25/50 m), which consists mainly of phytoplankton, to a higher trophic level diet containing mesozooplankton, was detected. The capacity for adults to consume more zooplankton food items may minimize their food competition with juveniles, which rely mostly on phytoplankton food items. This suggests "diet shift with ontogeny" which may somehow help krill keep their dietary energy budget balanced and well adapted to the Antarctic marine ecosystem as a dominant species.展开更多
基金the financial support provided by the National Natural Science Foundation of China(32022067)。
文摘Enzymatic hydrolysis,isolation,and purification might make a great deal of difference in antioxidant activity and antigenicity of peptide components.This study aimed to isolate and purify antioxidant peptide components from Antarctic krill and evaluate their allergenicity of them.Electron paramagnetic resonance(EPR)spectroscopy results indicated 3-10 kDa Antarctic krill hydrolysates(AKHs)had higher DPPH and·OH radical scavenging rates.And the second component(N2-2)purified 3-10 kDa hydrolysate showed better ability to scavenge DPPH and·OH radicals(P<0.05),which were(47.43±2.18)%and(34.33±1.25)%,respectively.Additionally,indirect-ELISA results revealed that N2-1 had a weaker ability to bind specific IgE and that N2-2 had a lower binding capability to specific IgG1(P<0.05).And N2-2 had a higher EC50 value of(5.29±0.95)ng/mL(P<0.05)in cell degranulation assay,which was about 13.80 times that of Antarctic krill.Therefore,N2-2 might be the potential source of the antioxidant peptides with lower allergenicity.
基金supported by the National Key R&D Program of China(Nos.2020YFD0901204,2017YFC1600706)the Natural Science Foundation of Shanghai(No.22ZR 1478500)。
文摘The objective of this study was to determine the quality changes and shelf life of ready-to-eat roasted Antarctic krill,either untreated(CT)or treated with sodium diacetate(SD)or sodium diacetate and a deoxidizer(SDD),during storage at room temperature(25℃)by using sensory,physiochemical,and microbial assessment.Additionally,fluoride accumulation in this food product was used to evaluate its safety.Analysis showed that the addition of SD and SDD resulted in better sensory scores compared of that of CT samples(P<0.05).Accordingly,microorganism growth and total basic nitrogen(TVB-N)were maintained at a low level for the duration of storage with SD and SDD treatments.The total viable counts of SD and SDD reached(4.58±0.08)log(CFU g^(−1))and(4.20±0.11)log(CFUg^(−1)),respectively.The mold was found after 6 and 18 days for SD and SDD treatment,and the numbers reached 5.2×10^(6) and 8.5×10^(4) respectively at the end of shelf life.The TVB-N values from CT continuously increased during the whole storage.While TVB-N values from SD and SDD remained significantly less change(P<0.05)during the early 20 days of the storage,and the values reached(12.11±0.07)mg(100 g)^(−1) and(10.88±0.15)mg(100 g)^(−1) on day 33 and day 70,respectively.Importantly,SDD treatment effectively minimized the oxidation values and retained the color of ready-to-eat roasted Antarctic krill.Our results showed that the shelf life of ready-to-eat roasted Antarctic krill treated with SDD was extended by up to 52 days.Additionally,rats fed ready-to-eat roasted Antarctic krill showed accumulation of fluoride exclusively in the thighbone.The accumulation of fluoride residues in the thighbone showed concentration-dependent.The concentrations of fluoride residues in rats were(1760.03±38.21),(2371.52±42.15)mgkg^(−1) and(3615.44±30.53)mgkg^(−1),which were less than sodium fluoride feeding group(4621.01±28.67)mgkg^(−1).The results suggested that the SD and SDD treatments led to better quality and shelf life extension of ready-to-eat roasted Antarctic krill during storage at room temperature(25℃).Therefore,the ready-to-eat roasted Antarctic krill can be of great interest to the seafood industry.
文摘Fog Computing(FC)provides processing and storage resources at the edge of the Internet of Things(IoT).By doing so,FC can help reduce latency and improve reliability of IoT networks.The energy consumption of servers and computing resources is one of the factors that directly affect conservation costs in fog environments.Energy consumption can be reduced by efficacious scheduling methods so that tasks are offloaded on the best possible resources.To deal with this problem,a binary model based on the combination of the Krill Herd Algorithm(KHA)and the Artificial Hummingbird Algorithm(AHA)is introduced as Binary KHA-AHA(BAHA-KHA).KHA is used to improve AHA.Also,the BAHA-KHA local optimal problem for task scheduling in FC environments is solved using the dynamic voltage and frequency scaling(DVFS)method.The Heterogeneous Earliest Finish Time(HEFT)method is used to discover the order of task flow execution.The goal of the BAHA-KHA model is to minimize the number of resources,the communication between dependent tasks,and reduce energy consumption.In this paper,the FC environment is considered to address the workflow scheduling issue to reduce energy consumption and minimize makespan on fog resources.The results were tested on five different workflows(Montage,CyberShake,LIGO,SIPHT,and Epigenomics).The evaluations show that the BAHA-KHA model has the best performance in comparison with the AHA,KHA,PSO and GA algorithms.The BAHA-KHA model has reduced the makespan rate by about 18%and the energy consumption by about 24%in comparison with GA.This is a preview of subscription content,log in via an institution to check access.
基金financially supported by the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2022 QNLM030002)the National Key R&D Program of China‘Formation Mechanism of Antarctic Krill Fishery and Key Technologies for Efficient Utilization of Resources’:Antarctic Krill High Value Product Creation and Industrialization Demonstration(No.2018YFC1406806)the Technology Innovation Project of Qingdao Marine Science and Technology Pilot National Laboratory,Shandong Provincial Marine Science,the Technology Fund Major‘Dark Blue Fishery’4-2:Construction of Antarctic Krill Processing Technology Process System(No.2018SDKJ0304-2)。
文摘This work conducted a four-week metabolism test on rats to study the digestion and absorption characteristics of five protein-based krill products prepared from Antarctic krill as raw material.It aimed to provide theoretical support for the effective use of Antarctic krill protein and the development of novel protein resources.The results showed that the weight gain and true digestibility of the rats fed with krill meat,surimi and ordinary krill powder were significantly higher(P<0.05)than those of the rats fed with traditional casein.Compared to casein,proteins from the five Antarctic krill products were found to significantly improve the net protein utilization(P<0.05),and reduce the total cholesterol and triglycerides in the serum of rats(P<0.05).In summary,the Antarctic krill protein-based products with high nutritional values can be used as a potential novel protein resource in the food industry.
基金National Natural Science Foundation of China under contract No. 0487013 and Office ofPolar Expedtion of China.
文摘The different forms fluoine in different parts of molting process of krill was analyzed by culture of Antarctic krill (Euphausia superba). The results shaw that fluorine amount in cuticle is up to 90% of total in the krill. During the krill molting process, the fluorine content in cuticle and muscle varies alternatively. This is to say, the fluorine content in new cuticle and muscle is much lower after molted, the fluorine in krill comes from seawater by biological absorption of the krill, and the fluorine absorbed by krill lost with the old cuticle at the end stage of molting process. Meanwhile, the new molting process starts again. The evidence is proved by the change of different forms fluorine content in cuticle and muscle during krill’s molting process. At last the author proposes the fluorine enriching process model of Antarctic krill.
文摘Phospholipids are one of the major bioactive ingredients of Antarctic krill Euphausea superba. A feasible and effective extraction method of Antarctic krill oil was investigated and modified by orthogonal test which the ratio of solid to liquid was 1:2.5, extraction time was 5 min, ratio of ethyl acetate (EA) and n-butanol (BuOH) was 1:1. With this method, the extract of krill oil has a higher phospholipids content of 27.7% - 42.3%, together with total oil yields of 4.15% - 6.18%.
文摘Antarctic krill(Euphausia superba)oil has been gaining increasing attention due to its nutritional and functional potentials.Krill oil usually contains a high concentration(about 50%)of phospholipids(AKOP)rich in DHA and EPA accompanied with 30%–40%triacylglycerols.Phospholipids can be made into liposomes without emulsifiers due to its amphiphilic characteristics.However,the absorption kinetics of AKOP liposome in vivo is not clear,which restrict the molecular mechanism analysis related to its distinct bioactivities.The lipid analysis in serum,small intestinal content and wall was carried out after oral administration of AKOP liposome to illustrate its absorption kinetics in blood and the digestive tract of healthy mice by single gavage.The major type of the obtained AKOP was phosphatidylcholine,and the total contents of the DHA and EPA were 29.31%.AKOP liposome was almost completely digested in the small intestine in 1 h and the hydrolysis products could be quickly absorbed by intestinal enterocytes.The DHA in serum peaked at 2 h after administration of AKOP liposome.AKOP liposome could be quickly digested and absorbed in vivo.The obtained results might provide a scientific basis for the molecular mechanism analysis related to distinct bioactivities of Antarctic krill oil phospholipid.
基金Project was supported by the State Antarctic Committeethe National Natural Science Foundation of China
文摘The aim of the study is to investigate the existing form and the partitioning pattern of fluoride in krill (Euphusia superba) by analysing the fluoride and other elements in various part of krill, primarily to approach the potential concentrating mechanism and the effect of fluoride in krill on the geochemical characteristics of fluoride in the Antarctic ecoenvironment. The results of the study show that the amount of flouride in various part of krill has a considerable difference. Most of fluoride is concentrated in the carapace, up to 4028μg/g, and the head and legs, respectively 2724μg/g and 2828μg/g. The muscle contains the least flouride with amount of 226μg/g. The amount of fluoride in whole freeze-dried krill is averagely 1232μg/g, which indicates that the functional position of fluoride in krill is mainly located at the crust. Only a few of fluoride is found in the chitin of the carapaces (200μg/g), which exhibits that fluoride in the carapaces exists mostly in the form of the
基金supported by the Key Research and Development Project of Shandong Province (No.2015 GSF115005)the Huimin Special Fund of Qingdao Municipal Achievement Transformation Plan (No.15-9-2-120NSH)the National Natural Science Foundation of China (No.31101380)
文摘Water-washing removes fluoride from Antarctic krill but produces large volumes of wash water containing water-soluble proteins and fluoride. The freeze concentration method was tested to determine if it could be used to recover water-soluble proteins while leaving the fluoride in solution. After freezing and thawing the wash water, protein and fluoride contents of the thawed fractions were determined to explore the melting regularity of components in the wash water. The highest concentration factors of protein and fluoride were obtained after 80 min of thawing, such as 1.48 ± 0.06 and 1.35 ± 0.04 times, respectively. The free amino-nitrogen(FAN) content and sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern results revealed that the highest concentrations of all ingredients were obtained after 80 min of the process. The degree of hydrolysis of all fractions from the thawing process fluctuated in a narrow range around 12% during the entire process, indicating that the thawing order did not change with various proteins or time during the entire thawing course. These results demonstrate that the freeze concentration method can be used to concentrate protein solutions, even those with fluoride. It was concluded that condensation was achieved and no ingredient could be separated, regardless of fluoride, amino acids, or different proteins in the water.
基金sponsored partly by the National Key R&D Program of China (No. 2018YFC1406801)the National Natural Science Foundation of China (No. 41776185)the Key Course Construction Program of the Shanghai Municipal Education Commission (Biological Oceanography) (No. A1-0201-00-1204)
文摘Each type of fishery has its own characteristic behavior, and understanding this condition is an important part of devel- oping and managing fishing operations comprehensively. Based on the random walk model, the relationship between distance and frequency distribution of adjacent fishing positions was analyzed by the Commission for Conservation of Antarctic Marine Living Resources (CCAMLR) Subareas 48.1, 48.2, and 48.3. The frequency of distances between consecutive hauls demonstrated a heavy- tailed distribution, which could be used to estimate the value of parameter μ in the power function F(l)~ l μ of a random walk model to determine the type of random walk patterns that characterize Chinese krill fishery. Results indicated that the fishing pattern of the Chinese krill fishery is consistent with the Lévy random walk model, with which the step-length is applied to analyze the walking pattern. When a defined walk in a space of dimension is greater than one, the steps made are in isotropic random directions. Fur- thermore, a strong and positive correlation between fishing behavior (using the parameter μ as an indicator) and catch per unit effort of the Chinese krill fishery was observed.
文摘Antarctic krill is thought to undergo an annual cycle of biological processes to cope with seasonal changes in their environment. The question of whether, and to what degree, seasonal environmental parameters such as photoperiod, food availability and temperature govern metabolism in krill is not clear. In this long-term laboratory study, respiration rates were determined in krill incubated under simulated natural light cycle or total darkness, subjected to fed or starved conditions and on krill kept at different temperatures (-1°C, 1°C and 3°C). There was a strong and significant increasing trend of respiration rates with month in all experimental treatments. In August (late winter), the mean respiration rates ranged between 0.22 - 0.35 μL O2 mg.DW-1.hr-1 for krill in both simulated seasonal light and complete darkness, and 0.25 - 0.26 μL O2 mg.DW-1.hr-1 for both fed and starved krill. Mean maximal respiration rates were recorded in October and December for all light and feeding treatments (0.46 - 0.56 μL O2 mg.DW-1.hr-1). Mean respiration rates for krill in the temperature treatments ranged between 0.24 - 0.30 μL O2 mg.DW-1.hr-1 in September reaching mean maximal rates in November and February (0.60 - 0.71 μL O2 mg.DW-1.hr-1). The covariate total length of krill was found to be non-significant and there was generally no significant interaction of experimental treatment with month and only for photoperiod comparison was the treatment main effect significant. The dark treatment gave higher respiration rates, and this needs careful interpretation. Results here suggest that, although light, food availability and temperature significantly affect metabolic rates,
基金This study was supported by the CAS know ledge innov ation program KZCX2-303.
文摘Antarctic krill (Euphausia superba) were collected from the Prydz Bay region during the austral summer of 1999/2000. The sample-collection was made at 15 sites in 3 longitudinal transects. Although krill were encountered at 14 sites, the abundance was comparatively low in general. The main component of the krill population was of post-larval stages. The mean numerical and weight density of krill integrated for all sampling stations in the survey area were 16.17 ind.1000 m-3 and 12.02 g 1000 m-3 , respectively. In the survey area, stations with larger krill density are mainly located in the slope zone, except that the largest sample was collected in the open sea zone. No krill occurred in the only station of the shelf zone during our investigation. Krill collected from the slope zone were under better growth condition than those from the open sea zone, but when the survey area is considered as a whole, the growth condition is normal. The results of the comprehensive analysis of the environmental factors show that the three large sample stations seem to be related with the cold water mass at 75 m depth and the confluence area between the high and low Chl a centers at the depth of 25 m.
基金supported by the Marine S&T Fund of Shandong Province for the Pilot National Laboratory for Marine Science and Technology (Qingdao) (Nos. 2018 SDKJ0304-4-2, 2018SDKJ0303-1)the Central Public-Interest Scientific Institution Basal Research Fund, Chinese Academy of Fishery Sciences (Nos. 2017HY-XKQ01-01, 2016ZD0902, 2018GH10)+3 种基金the Central Public-Interest Scientific Institution Basal Research Fund, YSFRI, CAFS (No. 20603022018025)the Aoshan S&T Innovation Project from Qingdao National Laboratory for Marine Science and Technology (No. 2015ASKJ02-02-04)the Antarctic Marine Biological Resources Development and Utilization Project from the Ministry of Agriculture and Rural Affairs, People’s Republic of China (2017)the Financial Fund of the Ministry of Agriculture and Rural Affairs, People’s Republic of China (Nos. NFZX2018, FSTICE2019)
文摘Lipase from Antarctic krill,with a molecular weight of 71.27kDa,was purified with ammonium sulfate precipitation and a series of chromatographic separations over ion exchange(DEAE)and gel filtration columns(Sephacryl S-100),resulting in 5.2%recovery with a 22.4-fold purification ratio.The optimal pH and temperature for enzyme activity were 8.0 and 45℃,respectively.Purified lipase had Km and Vmax values of 3.27mmolL−1 and 2.4Umg−1,respectively,using p-nitrophenyl laurate as the substrate.Lipase activity was enhanced by adding Ca2+and Mg2+ions in the concentration ranges of 0–0.5mmolL−1 and 0–0.3mmolL−1,respectively,while the activity was inhibited by a further increase in these ion concentrations.Fe3+and Cu2+ions showed obvious inhibitory effects on enzyme activity,and the inhibition rates were 71.8%and 53.3%when the ion concentrations were 0.5mmolL−1.
基金Supported by the Impact and Response of Antarctic Seas to Climate Change from Polar Research Institute of China(No.RFSOCC2020-2022-No.18)the National Science Foundation of Tianjin(No.19JCZDJC40600)the National Natural Science Foundation of China(No.42176198)。
文摘Antarctic krill is the key species of ecological system in the Amundsen Sea.At present,the suitable distribution is unobtainable by scientifi c surveys or data from the fi shery.In this paper,the maximum entropy algorithm(Maxent)was used to obtain the potential distribution of adult Antarctic krill in order to provide useful information and reasonable reference for the policy on protecting potential krill habitats around the Amundsen Sea.Occurrence points and 17 environmental variables were used to simulate the distributions.Results show that the high and moderate suitable habitats lie between 65°S and 72°S in the Amundsen Sea.The high suitable habitat accounts for 8.1%of the total area of the Amundsen Sea.The sea ice persistence(ICE),total phytoplankton(PHYC),and the minimum value of dissolved iron(Fe_min)are the three dominant contributors to the model.Results from the response curves show that Antarctic krill preferred habitats with ICE of 0.42-0.93,PHYC of 2.48-2.77 mmol/m^(3) and Fe_min of(7.10×10^(-5))-(9.45×10^(-5))mmol/m 3.Positive trends existed in the PHYC of the high and moderate suitable habitat,and a positive trend existed in the Fe_min of moderate suitable habitat.However,the probability of presence of Antarctic krill will decrease if the increase of the PHYC and Fe_min continues.
文摘The cause of the concentration of fluoride in Antaractic krill is studied by the analysis of the characteristics of fluoride change in the cuticle of the krill before and after moulting. Associated with other related information, the source and accumulating mechanism of fluoride in krill are also disscussed. Results show that as an inorganic medium the cuticle of krill has the second concentrating function and action to fluoride after moulting, which has nothing to do with the biological action of the krill. The fluoride is concentrated from seawater, which is prosecuted mainly in the form of ion exchange.
文摘Age groups of Antarctic krill ( Euphausia superba Dana) in the Prydz Bay region were studied by distribution mixture analysis based on length/frequency data collected by R/V Jidi during the 1989/1990 and 1990/1991 austral summer. Five age groups were determined, i.e. 1 +, 2 +, 3 +, 4 +, and 5 + , or six age groups in all, if the 0 + larvae were included. The mean body length of 1 + to 5 + age groups was 25.70 mm, 40.47 mm, 45.52 mm, 50.52 mm and 54.52 mm respectively. Supposing the difference in body length between successive age groups is a reflection of the yearly growth, the maximum growth rate occurred during the period from 1 + juveniles to 2 + subadults (14.77 mm/a). From 2 + subadults to 3 + adults the growth rate dropped steeply (5.05 mm/a) because at this stage, increase of body length was substituted, to a great extent, by the growth of sexual products. From 3 + onwards the growth rate was maintained at a relatively low level and decreased slowly with age. The relative abundance of age groups 1 + and 2 +, in our sample must be much lower than that in the real population owing to both the large mesh size we used and the distribution difference between juveniles and adults. If we left aside 1 + and 2 + age groups and just looked at the relative abundance of adults, we found that age group 3 + dominated the adult population and that the relative abundance decreased sharply with increasing age. If this situation is normal, one can expect an extremely high mortality rate in adults, 82.6% from 3 + to 4 + and 94.0% from 4 + to 5 +. This is reasonably expectable for the Prydz Bay region.
基金Chinese Polar Environment Comprehensive Investigation&Assessment Programmes under contract No.CHINARE2016-01-05the Scientific and Technological Innovation Project financially supported by Qingdao National Laboratory for Marine Science and Technology under contract No.2015ASKJ01the National Natural Science Foundation of China under contract No.41206180
文摘As one of the most common and dominant species in the Southern Ocean, Antarctic krill(Euphausia superba)play a significant role in food web structure and the process of energy flow. The diet of Antarctic krill in the Prydz Bay during austral summer of 2012/2013 was investigated and the ontogenetic shift in krill diet was evaluated using the stable isotope method. The nitrogen stable isotope values(δ^(15) N) of adults((2.78±0.58)‰) were much higher than those of juveniles((1.69±0.70)‰), whereas the carbon stable isotope values(δ^(13) C) of adults(–(28.26±1.08)‰) were slightly lower than those of juveniles(–(27.48±1.35)‰). Particulate organic matter(POM)from 0, 25, and 50 m depth combined(0/25/50 m) represented phytoplankton food items. The results showed that phytoplankton food items in surface water and mesozooplankton were two essential food items for Antarctic krill in the Prydz Bay during summer. POM(0/25/50 m) contributes 56%–69% and 26%–34% to the diet of juvenile and adult krill, respectively, whereas mesozooplankton composes 13%–34% and 58%–71% of the diet of juvenile and adult krill, respectively. Thus, an ontogenetic diet shift from POM(0/25/50 m), which consists mainly of phytoplankton, to a higher trophic level diet containing mesozooplankton, was detected. The capacity for adults to consume more zooplankton food items may minimize their food competition with juveniles, which rely mostly on phytoplankton food items. This suggests "diet shift with ontogeny" which may somehow help krill keep their dietary energy budget balanced and well adapted to the Antarctic marine ecosystem as a dominant species.
