Purification of antimicrobial peptide from Antarctic Krill (Euphausia superba) and its function mechanism

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 5.0 mg mL^?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: 1) CMCC-1 could inhibit cell division at logarithmic phase. 2) The protein and reducing sugar content, and the conductivity of culture medium increased, and the activity of alkaline phosphatase and β-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 cells 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 of S. 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 of S. aureu.     

Study on the distribution,abundance and growth condition of Antarctic Krill(Euphausia superba)in the Prydz Bay region,Antarctica during the Austral summer of 1999/2000

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 -3and 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 fa     

Evaluation of the biological toxicity of fluorine in Antarctic krill

Antarctic krill is a potentially nutritious food source for humans, but fluorine(F) toxicity is a matter of concern. To evaluate the toxicity of F in Antarctic krill, 30 Wistar rats were divided into three groups with different dietary regimens: a control group, a krill treatment group(150 mg·kg-1 F), and a sodium fluoride(NaF) treatment group(150 mg·kg-1 F). After three months, F concentrations in feces, plasma, and bone were determined, and the degree of dental and skeletal fluorosis was assessed. The F concentrations in plasma and bone from the krill treatment group were 0.167 0±0.020 4 mg.L-1 and 2 709.8±301.9 mg·kg-1, respectively, compared with 0.043 8±0.005 5 mg·L-1 and 442.4±60.7 mg·kg-1, respectively, in samples from the control group. Concentrations of F in plasma and bone in the krill treatment group were higher than in the control group, but lower than in the NaF treatment group. The degree of dental fluorosis in the krill treatment group was moderate, compared with severe in the NaF treatment group and normal in the control group. The degree of skeletal fluorosis did not change significantly in any group. These results showed that the toxicity of F in Antarctic krill was lower than for an equivalent concentration of F in NaF, but it was toxic for rats consuming krill in large quantities. To conclude, we discuss possible reasons for the reduced toxicity of F in Antarctic krill. The present study provides a direct toxicological reference for the consideration of Antarctic krill for human consumption.     

Evaluation of the biological toxicity of lfuorine in Antarctic krill

Antarctic krill is a potentially nutritious food source for humans, but lfuorine （F） toxicity is a matter of concern. To evaluate the toxicity of F in Antarctic krill, 30 Wistar rats were divided into three groups with different dietary regimens：a control group, a krill treatment group （150 mg＆#183;kg-1 F）, and a sodium lfuoride （NaF） treatment group （150 mg＆#183;kg-1 F）. After three months, F concentrations in feces, plasma, and bone were determined, and the degree of dental and skeletal lfuorosis was assessed. The F concentrations in plasma and bone from the krill treatment group were 0.167 0＆#177;0.020 4 mg.L-1 and 2 709.8＆#177;301.9 mg＆#183;kg-1, respectively, compared with 0.043 8＆#177;0.005 5 mg＆#183;L-1 and 442.4＆#177;60.7 mg＆#183;kg-1, respectively, in samples from the control group. Concentrations of F in plasma and bone in the krill treatment group were higher than in the control group, but lower than in the NaF treatment group. The degree of dental lfuorosis in the krill treatment group was moderate, compared with severe in the NaF treatment group and normal in the control group. The degree of skeletal lfuorosis did not change signiifcantly in any group. These results showed that the toxicity of F in Antarctic krill was lower than for an equivalent concentration of F in NaF, but it was toxic for rats consuming krill in large quantities. To conclude, we discuss possible reasons for the reduced toxicity of F in Antarctic krill. The present study provides a direct toxicological reference for the consideration of Antarctic krill for human consumption.     

扁舵鲣抗氧化肽分离纯化及结构鉴定

【目的】从扁舵鲣(Auxis thazard)的木瓜蛋白酶酶解产物中分离鉴定具有较高1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除率的抗氧化肽。【方法】用木瓜蛋白酶水解扁舵鲣,以DPPH自由基清除能力为检测指标,通过超滤、凝胶过滤层析和反向高效液相色谱分离抗氧化肽,再经过超高效液相/三重四级杆飞行时间质谱(UPLC/Xevo G2-XS QTOF)进行结构鉴定。【结果】从酶解产物中获得3种抗氧化肽,其氨基酸序列分别为β-丙氨酸-1-甲基-L-组氨酸(241 u)、Gly-Ala-Gly-Gly-Pro(357 u)和Val-Glu(246 u)。【结论】扁舵鲣的木瓜蛋白酶酶解产物含有抗氧化活性的肽类,可为其抗氧化肽的开发提供理论依据。     

Purification and Characterization of a Novel Hydrolase That Can Specifically Degrade the Polysaccharide Isolated from Green Seaweed Ulva prolifera

The extracellular polysaccharide hydrolase-producing strain EP-1 was isolated from seawater and identified as Paenibacillus pabuli. Furthermore, a homogeneous extracellular polysaccharide hydrolase from Paenibacillus pabuli EP-1 was purified by combining ion-exchange chromatography and size exclusion chromatography with a purification fold of 90.69 and recovery of 16.23%. Characterization of the purified polysaccharide hydrolase revealed a molecular mass of 38 k Da and optimum activity at 45℃ and pH 6.0. The polysaccharide hydrolase maintained its stability within a wide range of pH(3.0–12.0) and thermal stability when the temperature was below 50℃. The presence of Hg²⁺, Fe²⁺, Mn²⁺, Co²⁺ and SDS notably decreased hydrolase activity, and organic solvents such as formaldehyde, acetone, DMF and acetonitrile completely inhibited hydrolase activity. The purified hydrolase had no activity on agar, carrageenan, gellan gum, sodium alginate, or starch, but effectively hydrolyzed the polysaccharide from Ulva prolifera. The Km and Vmax values of this hydrolase were 43.84 mg m L^-1 and 4.33 mg m L^-1 min^-1, respectively. The sequence analysis with quantitative time-of-flight mass spectrometry indicated that the hydrolase was an endoglucanase.     

Influence of sea ice and sea surface temperature on the abundance of Antarctic krill in Area 48.2

In this paper we examine the relationship between Antarctic krill catch, sea ice concentration, and sea surface tempera- ture （SST）. Data on the Antarctic krill catch from 2003 to 2010 in CCAMLR Area 48.2 were combined with sea ice and SST data. Results showed that krill fishing in Area 48.2 took place from February to August each year but the catch was concentrated from March to July, with production during this period accounting for about 99.3% of the annual catch. Regression analysis showed that the catch per unit effort （CPUE） was clearly related to sea ice concentration and SST intervals. CPUE was negatively correlated with the area of sea ice among years （R2=0.64）, and the correlation was strongest （R2=0.71） when sea ice concentration was greater than 90%. Over the months the CPUE initially increased, then decreased as the area of sea ice increased. The relationship was strongest （R2=0.88） when the concentration of sea ice was 60%--70%. There was no negative correlation among years between CPUE and the ice-free area when S ST was between -2 ℃ and 3 ℃ （R2=0.21）, but there was a significant negative correlation when SST was between 1 ℃ and 2℃ （R2=0.82）. Over the months, CPUE initially increased then decreased with increasing sea ice-free area, and the relationship was strongest （R2=0.94） when SST was between 0℃and 1 ℃. This study shows that sea ice concentra- tion and SST have significant effects on the abundance of krill in Area 48.2, and the findings have practical significance for the use and conservation of Antarctic krill resources.     

Purification and Characterization of An Alkaline Protease from Acetes chinensis

An alkaline protease from Acetes chinensis was purified and characterized in this study. The steps of purification include ammonium sulfate precipitation, ion-exchange chromatography with Q-sepharose Fast Flow, gel filtration chromatography with S300 and the second ion-exchange chromatography with Q-sepharose Fast Flow. The protease was isolated and purified, which was present and active on protein substrates （azocasein and casein）. The specific protease activity was 17.15 folds and the recovery was 4.67. The molecular weight of the protease was estimated at 23.2kD by SDS-PAGE. With azocasein as the susbstrate, the optimal temperature was 55℃ and the optimal pH value was 5.5. Ion Ca^2＋ could enhance the proteolytic activity of the protease, while Cu^2＋, EDTA and PMSF could inhibit its activity.     

福安肽-03的分离纯化及其一级结构解析

通过盐析、离子交换、凝胶过滤和疏水层析等分离纯化,同步进行抗血管生成和抗肿瘤生长检测,从赤魟(Dasyatis akajei)组织获得强抗血管生成成分福安肽-03(Fuantai-03,FAT-03)的纯品(纯度>95%);使用Edman降解法测定FAT-03 N-末端氨基酸组成和序列,RACE系统技术解析FAT-03的一级结构。结果表明:FAT-03明显抑制鸡胚绒毛尿囊膜血管生成和BALB/c裸小鼠Lewis肺癌的生长及肝转移,且其效果与剂量相关。FAT-03分子的一级结构即其氨基酸组成和序列已被确定。     

Identification and Characterization of a Novel Alkali-and High Temperature-Tolerant Lipase(Lip4346) from a Macroalgae-Associated Bacterial Strain

A novel lipase gene(lip4346)encoding a primary translation product with 176 amino acids was screened from the genome fine mapping of the macroalgae-associated bacterial strain Microbulbifer sp.YNDZ01.Macroalgae were collected from the coast of the Halmahera Island of Indonesia.The lip4346 gene was cloned and heterologously expressed in Escherichia coli.The purified recombinant Lip4346 protein had a molecular mass of 19 k Da,a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE),and a maximum enzyme activity of 31.2 U m L-1.The optimal temperature and pH for the lipase activity of Lip4346 were 70℃and 10.0,respectively.Lip4346 was tolerant with a number of organic solvents and detergents,and was active toward triacylglycerols and p-nitrophenyl esters with short-and medium-chain lengths.The unique characteristics of Lip4346 indicate that it is a promising nonaqueous biocatalyst for industrial applications.     

Novel Lipase from Golden Pompano (Trachinotus ovatus) Viscera: Purification,Characterization,and Application in the Concentrating of n-3 Polyunsaturated Fatty Acids

Lipases have been widely applied in a variety of industrial fields,such as food,pharmaceuticals,biofuels,and biotechnology.Recent years have witnessed a great interest in modifying lipids for the production of triacylglycerols enriched with n-3 polyunsaturated fatty acids (PUFAs).Here,a novel salt-tolerant,organic solvent-stable,and bile salt-activated lipase was purified from golden pompano (Trachinotus ovatus) viscera,which was named as golden pompano lipase (GPL).GPL had a specific activity o...     

Definition of Arctic and Antarctic Sea Ice Variation Index

1　Introduction Itiswellknownthatseaiceinthepolarregionplaysanimportantroleintheglobal climatechangesasapartofclimatesystem(Carleton1989;YuanandMartinson2000, 2001;ChengandBian2002;LiuandMartinson2002;LiuandZhang2004;Gigorand Wallace2002etal).Infact,numerousmodelingstudiessuggestanimportantinfluence throughtheseaicefieldsalone(Grumbine1994,Meehl1990,Rindetal.1995).Inor dertounderstandthevariabilityofArcticandAntarcticseaicealongwiththepossiblecon nectionswithclimaticanomaliesindetail…     

Comparison of the defluoridation efficiency of calcium phosphate and chitin in the exoskeleton of Antarctic krill

Calcium （Ca）, phosphorus （P）, and chitin are the main components of the exoskeleton of krill. Defluoridation of a solution of sodium fluoride （NaF） using calcium phosphate （Ca3（PO4）2） and chitin as defluoridation agents was studied. Orthogonal experiments were designed to find the optimum reaction conditions for defluoridation, to obtain the maximum defluoridation efficiency and fluoride removal capacity of calcium phosphate and chitin. At the same time, a comparison of the capacity of the two defluoridation agents was made. The results suggest that calcium phosphate has a far greater capability than chitin for the removal of fluoride （F） from water under similar reaction conditions. It is also suggested that Antarctic krill is likely to adsorb fluoride via compounds such as calcium phosphate, hydroxyapatite, and other compounds of Ca and P with the general form （Ca, X）x（PO4, HPO4, Y）y（OH, Z）z, in addition to chitin.     

Relationship between Antarctic sea ice and the climate in summer of China

The variations of sea ice are different in different regions in Antarctica, thus have different impacts on local atmospheric circulation and global climatic system. The relationships between the sea ice in Ross Sea and Weddell Sea regions and the synoptic climate in summer of China are investigated in this paper via diagnostic analysis methods by using global sea ice concentration gridded data covering Jan. 1968 through Dec. 2002 obtained from Hadley Center, combined with Geopotential Height on 500hPa and 100hPa over North Hemisphere and monthly precipitation and air temperatures data covering the corresponding period over 160 meteorological stations in China obtained from CMA （ China Meteorological Administration）. Results disclose that both these two regions are of indicative meanings to the climate in summer of China. The Ross Sea Region is the key sea ice region to the precipitation in Northeast China in summer. More sea ice in this region in September will result in less precipitation in Northeast China in the following June. Weddell Sea Region is the key sea ice region to the air temperature in Northeast China in summer. More sea ice in this region in September will contribute to lower air temperature in Northeast China in the following June.     

Distributions of surface sediments surrounding the Antarctic Peninsula and its environmental significance

We analyzed grain size composition to provide information on the types and distributions as well as depositional varieties of marine surface sediments from the area surrounding the Antarctic Peninsula. The samples retrieved from the study area contain gravel, sand, silt and clay. As suggested by bathymetry and morphology, the study area is characterized by neritic, hemipelagic and pelagic deposits. The glacial-marine sediments can be divided into two types, residual paratill and compound paratill, which are primarily transported by glaciers and as ice-rafted debris. Ocean current effects on deposition are more obvious, and the deposit types are distributed consistently with terrain variations.     

Cloning,Expression and Characterization of a Lipase Gene from Marine Bacterium Pseudoalteromonas lipolytica SCSIO 04301

Absract A lipase gene, lip1233, isolated from Pseudoalteromonas lipolytica SCSIO 04301, was cloned and expressed in E. coli. The enzyme comprised 810 amino acid residues with a deduced molecular weight of 80 k Da. Lip1233 was grouped into the lipase family X because it contained a highly conserved motif GHSLG. The recombinant enzyme was purified with Ni-NTA affinity chromatography. The optimal temperature and p H value of Lip1233 were 45℃ and 8.0, respectively. It retained more than 70% of original activity after being incubated in p H ranging from 6.0 to 9.5 for 30 min. It was stable when the temperature was below 45℃, but was unstable when the temperature was above 55℃. Most metal ions tested had no significant effect on the activity of Lip1233. Lip1233 remained more than original activity in some organic solvents at the concentration of 30%(v/v). It retained more than 30% activity after incubated in pure organic solvents for 12 h, while in hexane the activity was nearly 100%. Additionally, Lip1233 exhibited typical halotolerant characteristic as it was active under 4M Na Cl. Lip1233 powder could catalyze efficiently the synthesis of fructose esters in hexane at 40℃. These characteristics demonstrated that Lip1233 is applicable to elaborate food processing and organic synthesis.     

Purification and characterization of iron-cofactored superoxide dismutase from Enteromorpha linza

A superoxide dismutase was purified from Enteromorpha linza using a simple and safe procedure, which comprised phosphate buffer extraction, ammonium sulphate precipitation, ion exchange chromatography on Q-sepharose column, and gel filtration chromatography on Superdex 200 10/300GL. The E. linza superoxide dismutase （E/SOD） was purified 103.6-fold, and a yield of 19.1% and a specific activity of 1 750 U/rag protein were obtained. The SDS-PAGE exhibited E/SOD a single band near 23 kDa and the gel filtration study showed E/SOD＇s molecular weight is near 46 kDa in nondenatured condition, indicating it＇s a homodimeric protein. E/SOD is an iron-cofactored superoxide dismutase （Fe-SOD） because it was inhibited by hydrogen peroxide, insensitive to potassium cyanide. The optimal temperature for its maximal enzyme activity was 35℃, and it still had 29.8% relative activity at 0℃, then E/SOD can be classified as a cold-adapted enzyme. E/SOD was stable when temperature was below 40℃ or the pH was within the range of 5 10. The first 11 N-terminal amino acids orE/SOD were ALELKAPPYEL, comparison of its N-terminal sequence with other Fe-SOD N-terminal sequences at the same position suggests it is possibly a chloroplastic Fe-SOD.     

Purification and characterization of lectin from humoral fluids of Charybdis feriatus

1 INTRODUCTION Lectins have been regarded as having a puta- tive role in non-self recognition in vertebrate and invertebrate immunities (Arason, 1996; Matsushita, 1996; Olafsen, 1996; Vasta et al., 1999; Wilson, et al., 1999; Marques and Barracco, 2000). …