The research explored the extraction techniques of organic solvents of Antarctic kril oil and the effects of freezing temperature, extractant proportion, ex-traction time, drying temperature and ratio of material and ...The research explored the extraction techniques of organic solvents of Antarctic kril oil and the effects of freezing temperature, extractant proportion, ex-traction time, drying temperature and ratio of material and liquid on extraction ratio of Antarctic kril oil. Based on single-factor experiments, optimal extraction conditions were concluded as per response surface methodology, as fol ows： freezing tempera-ture at -38.5 ℃, the ratio of material and liquid at 1 g：6.7 ml, and drying tempera-ture at 66.8 ℃, where the yield rate of crude oil reached 13.71%.展开更多
The preliminary purification and antimicrobial mechanism of antimicrobial peptide from Antarctic Krill were studied in this paper. The results showed that the molecular weight range of antimicrobial polypeptide （CMC...The preliminary purification and antimicrobial mechanism of antimicrobial peptide from Antarctic Krill were studied in this paper. The results showed that the molecular weight range of antimicrobial polypeptide （CMCC-1） obtained by cation exchange chromatography was between 245-709D as detected by molecular sieve chromatography, and the minimum inhibition concentration （MIC） of CMCC-1 against Staphylococcus aureus was 5.0mgmL^-1. The antimicrobial mechanism of CMCC-1 was studied with S. aureus as indicator bacterium. Compared with control group, the results of the experimental group in which S. aureus was treated with CMCC-1 were as follows： l） CMCC-1 could inhibit cell division at logarithmic phase. 2） The protein and reducing sugar con- tent, and the conductivity of culture medium increased, and the activity of alkaline phosphatase and [3-galactosidase could be detected in the culture medium. 3） Observation under scanning electron microscope revealed that somatic morphology became irregular, and then somatic surface became coarse. The cell became much smaller, and most somatic ceils gathered. The boundary between cells became dim and finally fused as a whole. 4） Observation under transmission electron microscope showed that the surface of S. aureus became rough and the reproducing ability was restrained. The cell wall became thin and the cytoplasm shrunk. Substances inside cell leaked out, which caused cells death. 5） SDS-PAGE analysis showed that some bands disappeared, and the residual bands became vague. 6） The genomic DNA electrophoresis results showed that the genomic DNA bands ofS. aureus were not degraded but the brightness significantly reduced. Thus, it is supposed that CMCC-1 could destroy the cell wall and membrane of S. aureu, increase the cell membrane permeability and the leaking-out of intracellular substances, and thus cause the death ofS. aureu.展开更多
Ice krill is the keystone species in the neritic ecosystem in the Southern Ocean, where it replaces the more oceanic Antarctic krill. It is essential to understand the variation of target strength （TS in dB re l m^2...Ice krill is the keystone species in the neritic ecosystem in the Southern Ocean, where it replaces the more oceanic Antarctic krill. It is essential to understand the variation of target strength （TS in dB re l m^2） with the different body size to accurately estimate ice krill stocks. However, there is comparatively little knowledge of the acoustic backscatter of ice krill. The TS of individual, formalin-preserved, tethered ice krill was measured in a freshwater test tank at 38, 120, and 200 kHz with a calibrated split-beam echo sounder system. Mean TS was obtained from 21 individual ice krill with a broad range of body lengths （L： 13-36 iron）. The length （L, mm） to wet weight （W; mg） relationship for ice krill was 11/=0.001 21g^103~L35s （R2=0.96）. The mean TS-to-length relationship were TS38kHz=-177.4＋57log10（L）, （R^2=0.86）; TS120kHz= -129.9＋31.561ogf0（L）, （R2=0.87）; and TS200kHz=-117.6＋24.661ogre（L）, （R2=0.84）. Empirical estimates of the relationship between the TS and body length of ice krill were established at 38, 120, and 200 kHz and compared with predictions obtained from both the linear regression model of Greene et al. （1991） and the Stochastic Distorted Wave Born Approximation （SDWBA） model. This result might be applied to improve acoustic detection and density estimation of ice krill in the Southern Ocean. Further comparative studies are needed with in situ target strength including various body lengths of ice krill.展开更多
This study conducted a bibliometric analysis of 1251 articles related to Antarctic krill from 1960 to 2015, based on the Core Collection in Thomson Reuters＇ Web of Science. We analyzed the results from four aspects：...This study conducted a bibliometric analysis of 1251 articles related to Antarctic krill from 1960 to 2015, based on the Core Collection in Thomson Reuters＇ Web of Science. We analyzed the results from four aspects： annual distribution, Web of Science categories and the major journals, inter- national collaboration and author keywords. The Antarctic krill research has developed rapidly since 1978, with an increasing article output. The studies mostly focused on the fields of marine and freshwater biology, oceanography, and ecology. Polar Biology, Marine Ecology-Progress Series and Deep-Sea Research Part II-Topical Studies in Oceanography, were the top three journals to publish the Antarctic krill-related papers. Although Russia is the earliest state to report Antarctic krill, U.S.A. and England were leaders with the largest output quantity and the highest cooperation frequencies. The researches in PR China have taken a blooming since 2009 and will play a more and more important role in the world. The frequencies of author keywords were counted. The high-frequency keywords were further divided into four groups with cohesive subgroup analysis, which suggested the major themes. This paper depicts the existing publica- tions on Antarctic krill. Our goal is to serve a point of reference and provide the direction for the future work.展开更多
The information of trophic relationship is important for studying the Southern Ocean ecosystems. In this study, three dominant krill species, Euphausia superba, Thysanoessa macrura and Euphausia crystallorophias, were...The information of trophic relationship is important for studying the Southern Ocean ecosystems. In this study, three dominant krill species, Euphausia superba, Thysanoessa macrura and Euphausia crystallorophias, were collected from Prydz Bay, Antarctica, during austral summer of 2009/2010. The composition of fatty acids in these species was studied. E. superba and T. macrura showed a similar fatty acid composition which was dominated by C140, C16：0, EPA （eicosapentenoic acid） and DHA （decosahexenoic acid） while E. crystallorophias showed higher contents of C 18：1（n-9）, C 18： 1 （n-7）, DHA and EPA than the former two. Higher fatty acid ratios of C 18：1（n-9）/18：1（n-7）, PUFA （polyunsaturated fatty acid）/SFA （saturated fatty acid）, and 18PUFA/16PUFA indicated that E. crystallorophias should be classified as a typical onmivore with a higher trophic position compared with E. superba and T. rnacrura.展开更多
基金Supported by Postgraduate Scientific Research Foundation(A-2500-11-0079)Shanghai Engineering Research Center of Aquatic-Product Processing&Preservation Foundation(11DZ2280300)Aquaculture Genetics and Breeding Technology Center in Shanghai Ocean University(ZF1206)~~
文摘The research explored the extraction techniques of organic solvents of Antarctic kril oil and the effects of freezing temperature, extractant proportion, ex-traction time, drying temperature and ratio of material and liquid on extraction ratio of Antarctic kril oil. Based on single-factor experiments, optimal extraction conditions were concluded as per response surface methodology, as fol ows： freezing tempera-ture at -38.5 ℃, the ratio of material and liquid at 1 g：6.7 ml, and drying tempera-ture at 66.8 ℃, where the yield rate of crude oil reached 13.71%.
基金supported by the National Science and Technology Pillar Program(2013BAD13B03)National Natural Science Foundation of China(Grant 31201311)Special Scientific Research Funds for Central Non-profit Institutes,Yellow Sea Fisheries Research Institute(20603022012001)
文摘The preliminary purification and antimicrobial mechanism of antimicrobial peptide from Antarctic Krill were studied in this paper. The results showed that the molecular weight range of antimicrobial polypeptide （CMCC-1） obtained by cation exchange chromatography was between 245-709D as detected by molecular sieve chromatography, and the minimum inhibition concentration （MIC） of CMCC-1 against Staphylococcus aureus was 5.0mgmL^-1. The antimicrobial mechanism of CMCC-1 was studied with S. aureus as indicator bacterium. Compared with control group, the results of the experimental group in which S. aureus was treated with CMCC-1 were as follows： l） CMCC-1 could inhibit cell division at logarithmic phase. 2） The protein and reducing sugar con- tent, and the conductivity of culture medium increased, and the activity of alkaline phosphatase and [3-galactosidase could be detected in the culture medium. 3） Observation under scanning electron microscope revealed that somatic morphology became irregular, and then somatic surface became coarse. The cell became much smaller, and most somatic ceils gathered. The boundary between cells became dim and finally fused as a whole. 4） Observation under transmission electron microscope showed that the surface of S. aureus became rough and the reproducing ability was restrained. The cell wall became thin and the cytoplasm shrunk. Substances inside cell leaked out, which caused cells death. 5） SDS-PAGE analysis showed that some bands disappeared, and the residual bands became vague. 6） The genomic DNA electrophoresis results showed that the genomic DNA bands ofS. aureus were not degraded but the brightness significantly reduced. Thus, it is supposed that CMCC-1 could destroy the cell wall and membrane of S. aureu, increase the cell membrane permeability and the leaking-out of intracellular substances, and thus cause the death ofS. aureu.
基金Supported by the Korea Polar Research Institute(No.PP14020)the Korea Institute of Ocean Science and Technology(No.PN65250)
文摘Ice krill is the keystone species in the neritic ecosystem in the Southern Ocean, where it replaces the more oceanic Antarctic krill. It is essential to understand the variation of target strength （TS in dB re l m^2） with the different body size to accurately estimate ice krill stocks. However, there is comparatively little knowledge of the acoustic backscatter of ice krill. The TS of individual, formalin-preserved, tethered ice krill was measured in a freshwater test tank at 38, 120, and 200 kHz with a calibrated split-beam echo sounder system. Mean TS was obtained from 21 individual ice krill with a broad range of body lengths （L： 13-36 iron）. The length （L, mm） to wet weight （W; mg） relationship for ice krill was 11/=0.001 21g^103~L35s （R2=0.96）. The mean TS-to-length relationship were TS38kHz=-177.4＋57log10（L）, （R^2=0.86）; TS120kHz= -129.9＋31.561ogf0（L）, （R2=0.87）; and TS200kHz=-117.6＋24.661ogre（L）, （R2=0.84）. Empirical estimates of the relationship between the TS and body length of ice krill were established at 38, 120, and 200 kHz and compared with predictions obtained from both the linear regression model of Greene et al. （1991） and the Stochastic Distorted Wave Born Approximation （SDWBA） model. This result might be applied to improve acoustic detection and density estimation of ice krill in the Southern Ocean. Further comparative studies are needed with in situ target strength including various body lengths of ice krill.
文摘This study conducted a bibliometric analysis of 1251 articles related to Antarctic krill from 1960 to 2015, based on the Core Collection in Thomson Reuters＇ Web of Science. We analyzed the results from four aspects： annual distribution, Web of Science categories and the major journals, inter- national collaboration and author keywords. The Antarctic krill research has developed rapidly since 1978, with an increasing article output. The studies mostly focused on the fields of marine and freshwater biology, oceanography, and ecology. Polar Biology, Marine Ecology-Progress Series and Deep-Sea Research Part II-Topical Studies in Oceanography, were the top three journals to publish the Antarctic krill-related papers. Although Russia is the earliest state to report Antarctic krill, U.S.A. and England were leaders with the largest output quantity and the highest cooperation frequencies. The researches in PR China have taken a blooming since 2009 and will play a more and more important role in the world. The frequencies of author keywords were counted. The high-frequency keywords were further divided into four groups with cohesive subgroup analysis, which suggested the major themes. This paper depicts the existing publica- tions on Antarctic krill. Our goal is to serve a point of reference and provide the direction for the future work.
基金supported by Polar Project of State Oceanic Administration,China (CHINARE2013-01-05-02 and CHINARE2013-04-01-05)the National Natural Science Foundation of China (41206180)
文摘The information of trophic relationship is important for studying the Southern Ocean ecosystems. In this study, three dominant krill species, Euphausia superba, Thysanoessa macrura and Euphausia crystallorophias, were collected from Prydz Bay, Antarctica, during austral summer of 2009/2010. The composition of fatty acids in these species was studied. E. superba and T. macrura showed a similar fatty acid composition which was dominated by C140, C16：0, EPA （eicosapentenoic acid） and DHA （decosahexenoic acid） while E. crystallorophias showed higher contents of C 18：1（n-9）, C 18： 1 （n-7）, DHA and EPA than the former two. Higher fatty acid ratios of C 18：1（n-9）/18：1（n-7）, PUFA （polyunsaturated fatty acid）/SFA （saturated fatty acid）, and 18PUFA/16PUFA indicated that E. crystallorophias should be classified as a typical onmivore with a higher trophic position compared with E. superba and T. rnacrura.
