The cDNA of the delta-12 fatty acid desaturase gene, IgFAD2, was cloned from the marine microalgae Isochrysis galbana, a species capable of producing docosahexaenoic acid. Sequence analysis indicated that the open rea...The cDNA of the delta-12 fatty acid desaturase gene, IgFAD2, was cloned from the marine microalgae Isochrysis galbana, a species capable of producing docosahexaenoic acid. Sequence analysis indicated that the open reading frame measured a length of 1 158 bp and encoded 386 amino acids with a predicted molecular weight of 42.8 kDa and an isoelectric point of 9.2. Computational analysis of the protein sequence of IgFAD2 showed typical features of membrane-bound desaturase such as three conserved histidine boxes along with four membranespanning regions that were universally present among plant desaturases. Quantitative real-time PCR results showed that the abundance of IgFAD2 transcript was significantly upregulated under different environmental stresses including low temperature(15℃), high salinity(salinity of 62 and 93), and nitrogen starvation(220 μmol/L). Heterologous expression indicated that yeast cells transformed with a plasmid construct containing IgFAD2 could convert endogenous oleic acid(18:1^(?9), OA) into linoleic acid(18:2^(?9, 12), LA). These findings confirm that I. galbana IgFAD2 plays important roles in the biosynthetic pathways of unsaturated fatty acids.展开更多
In most bacteria,plants and algae,fatty acid biosynthesis is catalyzed by a group of freely dissociable proteins known as the type II fatty acid synthase(FAS II) system.In the FAS II system,enoylacyl carrier protein r...In most bacteria,plants and algae,fatty acid biosynthesis is catalyzed by a group of freely dissociable proteins known as the type II fatty acid synthase(FAS II) system.In the FAS II system,enoylacyl carrier protein reductase(ENR) acts as a determinant for completing the cycles of fatty acid elongation.In this study,the cDNA sequence of ENR,designated as IgENR,was isolated from the microalga Isochrysis galbana CCMM5001.RACE(rapid amplification of cDNA ends) was used to isolate the full-length cDNA of IgENR(1 503 bp),which contains an open reading frame(ORF) of 1 044 bp and encodes a protein of 347 amino acids.The genomic DNA sequence of IgENR is interrupted by four introns.The putative amino acid sequence is homologous to the ENRs of seed plants and algae,and they contain common coenzymebinding sites and active site motifs.Under different stress conditions,real-time quantitative polymerase chain reaction(RT-qPCR) showed the expression of IgENR was upregulated by high temperature(35℃),and downregulated by depleted nitrogen(0 mol/L).To clarify the mechanism of lipids accumulating lipids,other genes involved in lipids accumulation should be studied.展开更多
Phenol is a common industrial chemical produced and transported worldwide largely.Therefore,accidental spillage of phenol in the ocean causes an increasing concern.Microalgae are promising to remove phenol from marine...Phenol is a common industrial chemical produced and transported worldwide largely.Therefore,accidental spillage of phenol in the ocean causes an increasing concern.Microalgae are promising to remove phenol from marine waters.However,temperature and light intensity are two main factors that markedly influence biodegradation in marine environments.In this study,a marine golden alga Isochrysis galbana is selected to research the removal of phenol under different temperatures(10-30℃)and light intensities(0-240μmol/(m^2·s)).The results show that the most suitable temperature and light intensity for phenol removal are 20℃and 180μmol/(m2·s),respectively,and 100 mg/L of phenol can be completely removed by microalga in 24 h at these conditions.I.galbana can also remove phenol under dark and low-temperature conditions.The removal of phenol by I.galbana at diverse temperatures and light intensities conform to first-order kinetics,and the process under dark conditions conform to zero-order kinetics.Thus,I.galbana can be used in the in-situ bioremediation of polluted seawater by phenol.展开更多
本文研究了培养液中添加0、0.5、1.0、1.5和2.0 mg/m L NaHCO_3对球等鞭金藻(Isochrysis galbana)生长、细胞蛋白质含量及脂肪酸组成的影响,并进一步探讨了添加适宜NaHCO_3后不同培养阶段对细胞营养组成的影响。结果表明:NaHCO_3对球等...本文研究了培养液中添加0、0.5、1.0、1.5和2.0 mg/m L NaHCO_3对球等鞭金藻(Isochrysis galbana)生长、细胞蛋白质含量及脂肪酸组成的影响,并进一步探讨了添加适宜NaHCO_3后不同培养阶段对细胞营养组成的影响。结果表明:NaHCO_3对球等鞭金藻的生长和细胞营养价值有显著影响。批次培养模式下培养液中添加1.5 mg/m L NaHCO_3可以获得最大细胞密度和比生长率。球等边金藻细胞中蛋白质含量随培养液中NaHCO_3添加量的增大而显著减少;而细胞中得单不饱和脂肪酸(MUFA)显著增加,多不饱和脂肪酸(PUFA)显著降低。在添加1.5 mg/m L NaHCO_3的培养条件下,不同培养阶段的藻细胞蛋白和脂肪酸组成也有显著变化,随着培养时间的延长,SFA和MUFA含量逐渐增加,PUFA含量则显著减少。培养液中添加NaHCO_3有助于提升球等鞭金藻作为生物柴油原料的品质。展开更多
Marine microalga Isochrysis galbana is an important feed species with a high nutritional value.Different from other uni-cellular algae,its cell contains two chloroplasts which are the major sites for lipid synthesis.H...Marine microalga Isochrysis galbana is an important feed species with a high nutritional value.Different from other uni-cellular algae,its cell contains two chloroplasts which are the major sites for lipid synthesis.Here,we optimized a chloroplast isola-tion approach suitable for the isolation of I.galbana chloroplasts and determined the purity and integrity of the isolated chloroplasts through microscopic observations and enzyme activity assay.The chloroplast lipids were analyzed with a ultrahigh-performance li-quid chromatography-Q Exactive Orbitrap-mass spectrometry.This newly developed isolation approach is simple and reliable to isolate chloroplasts with high integrity and purity.The average yield of intact chloroplasts was 15.3%±0.1%.Glycolipids and acyl-glycerols were the main chloroplast lipids.Glycolipids accounted for 56.6%of chloroplast lipid.Digalactosyldiacylglycerol(DGDG),monogalactosyldiacylglycerol(MGDG)and sulfoquinovosyldiacylglycerol(SQDG)were the main glyceroglycolipids.The fatty acyl R1/R2 were mostly 18:4/16:1,18:3/16:1 and 18:4/18:5 in DGDGs,14:0/18:4,18:4/18:5,18:4/18:4 and 18:3/18:4 in MGDGs and 16:0/14:0,16:0/18:3,and 18:4/18:3 in SQDGs.In addition,diacylglycerol(DAG)was the most abundant acylglycerols;the content of 22:6/18:4-DAG was the highest.There was a little amount of glycosphingolipid(GSL)in chloroplast.Digalactosylmonoglyceride(DGMG),monogalactosylmonoglyceride(MGMG),sulfoquinovosylmonoacylglycerol(SQMG),monoglyceride(MAG),phospholi-pids(PLs),ceramide(Cer)and betaine lipids were nearly undetectable in chloroplast.The fatty acid proportions of DGDGs,MGDGs,SQDGs,DAGs,triglycerides(TAGs)and GSLs were either higher or lower than or similar to those of whole-cell.Collectively,our isolation approach is applicable to many aspects of chloroplast biology,and may offer a reference for the isolation of chloroplasts from other marine microalgae.展开更多
Effects of heavy metals on Isochrysis galbana (Parke ) were studied in our laboratory. The research focused on toxic effects of metals on algal cells, effects of water-soluble and lipid-soluble organic ligands on meta...Effects of heavy metals on Isochrysis galbana (Parke ) were studied in our laboratory. The research focused on toxic effects of metals on algal cells, effects of water-soluble and lipid-soluble organic ligands on metal toxicity and processes of metal uptake by cells. Interactions between two metals and the mechanisms involved were also studied in detail. Finally, some relationships between toxicity and chemical property of metals were revealed.展开更多
基金The Basic Scientific Fund for National Public Research Institutes of China under contract No.2017Q09the Aoshan Science and Technology Innovation Project of Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2016ASKJ02+3 种基金the National Natural Science Foundation of China-Shandong Joint Funded Project under contract No.U1606404the National Natural Science Foundation of China under contract Nos 41776176 and 41806201the 973 Project from Chinese Ministry of Science and Technology under contract No.2015CB755904the Shandong Provincial Natural Science Foundation under contract No.ZR2015PD003
文摘The cDNA of the delta-12 fatty acid desaturase gene, IgFAD2, was cloned from the marine microalgae Isochrysis galbana, a species capable of producing docosahexaenoic acid. Sequence analysis indicated that the open reading frame measured a length of 1 158 bp and encoded 386 amino acids with a predicted molecular weight of 42.8 kDa and an isoelectric point of 9.2. Computational analysis of the protein sequence of IgFAD2 showed typical features of membrane-bound desaturase such as three conserved histidine boxes along with four membranespanning regions that were universally present among plant desaturases. Quantitative real-time PCR results showed that the abundance of IgFAD2 transcript was significantly upregulated under different environmental stresses including low temperature(15℃), high salinity(salinity of 62 and 93), and nitrogen starvation(220 μmol/L). Heterologous expression indicated that yeast cells transformed with a plasmid construct containing IgFAD2 could convert endogenous oleic acid(18:1^(?9), OA) into linoleic acid(18:2^(?9, 12), LA). These findings confirm that I. galbana IgFAD2 plays important roles in the biosynthetic pathways of unsaturated fatty acids.
基金Supported by the National Natural Science Foundation of China(No.41106148)the Ocean Public Welfare Scientific Research Project(Nos.GHME2001SW02,200905019,200805039)the Science and Technology Development Program of Shandong Province(No.2011GHY11533)
文摘In most bacteria,plants and algae,fatty acid biosynthesis is catalyzed by a group of freely dissociable proteins known as the type II fatty acid synthase(FAS II) system.In the FAS II system,enoylacyl carrier protein reductase(ENR) acts as a determinant for completing the cycles of fatty acid elongation.In this study,the cDNA sequence of ENR,designated as IgENR,was isolated from the microalga Isochrysis galbana CCMM5001.RACE(rapid amplification of cDNA ends) was used to isolate the full-length cDNA of IgENR(1 503 bp),which contains an open reading frame(ORF) of 1 044 bp and encodes a protein of 347 amino acids.The genomic DNA sequence of IgENR is interrupted by four introns.The putative amino acid sequence is homologous to the ENRs of seed plants and algae,and they contain common coenzymebinding sites and active site motifs.Under different stress conditions,real-time quantitative polymerase chain reaction(RT-qPCR) showed the expression of IgENR was upregulated by high temperature(35℃),and downregulated by depleted nitrogen(0 mol/L).To clarify the mechanism of lipids accumulating lipids,other genes involved in lipids accumulation should be studied.
基金Supported by the National Marine Hazard Mitigation Service,Ministry of Natural Resource of the People’s Republic of China through its Commissioned Research Scheme(No.2018AA019)。
文摘Phenol is a common industrial chemical produced and transported worldwide largely.Therefore,accidental spillage of phenol in the ocean causes an increasing concern.Microalgae are promising to remove phenol from marine waters.However,temperature and light intensity are two main factors that markedly influence biodegradation in marine environments.In this study,a marine golden alga Isochrysis galbana is selected to research the removal of phenol under different temperatures(10-30℃)and light intensities(0-240μmol/(m^2·s)).The results show that the most suitable temperature and light intensity for phenol removal are 20℃and 180μmol/(m2·s),respectively,and 100 mg/L of phenol can be completely removed by microalga in 24 h at these conditions.I.galbana can also remove phenol under dark and low-temperature conditions.The removal of phenol by I.galbana at diverse temperatures and light intensities conform to first-order kinetics,and the process under dark conditions conform to zero-order kinetics.Thus,I.galbana can be used in the in-situ bioremediation of polluted seawater by phenol.
文摘本文研究了培养液中添加0、0.5、1.0、1.5和2.0 mg/m L NaHCO_3对球等鞭金藻(Isochrysis galbana)生长、细胞蛋白质含量及脂肪酸组成的影响,并进一步探讨了添加适宜NaHCO_3后不同培养阶段对细胞营养组成的影响。结果表明:NaHCO_3对球等鞭金藻的生长和细胞营养价值有显著影响。批次培养模式下培养液中添加1.5 mg/m L NaHCO_3可以获得最大细胞密度和比生长率。球等边金藻细胞中蛋白质含量随培养液中NaHCO_3添加量的增大而显著减少;而细胞中得单不饱和脂肪酸(MUFA)显著增加,多不饱和脂肪酸(PUFA)显著降低。在添加1.5 mg/m L NaHCO_3的培养条件下,不同培养阶段的藻细胞蛋白和脂肪酸组成也有显著变化,随着培养时间的延长,SFA和MUFA含量逐渐增加,PUFA含量则显著减少。培养液中添加NaHCO_3有助于提升球等鞭金藻作为生物柴油原料的品质。
基金supported by the Ningbo Science and Technology Research Projects(No.2019B10006)the Na-tional Key Research and Development Program of China(No.2019YFD0900400)+3 种基金the Zhejiang Major Science Pro-ject(No.2019C02057)the China Agriculture Research System of MOF and MARA,the Natural Science Founda-tion of Ningbo(No.2019A610416)the Ningbo Science and Technology Research Projects(No.2019C10023)the National Natural Science Foundation of China(No.31801724).
文摘Marine microalga Isochrysis galbana is an important feed species with a high nutritional value.Different from other uni-cellular algae,its cell contains two chloroplasts which are the major sites for lipid synthesis.Here,we optimized a chloroplast isola-tion approach suitable for the isolation of I.galbana chloroplasts and determined the purity and integrity of the isolated chloroplasts through microscopic observations and enzyme activity assay.The chloroplast lipids were analyzed with a ultrahigh-performance li-quid chromatography-Q Exactive Orbitrap-mass spectrometry.This newly developed isolation approach is simple and reliable to isolate chloroplasts with high integrity and purity.The average yield of intact chloroplasts was 15.3%±0.1%.Glycolipids and acyl-glycerols were the main chloroplast lipids.Glycolipids accounted for 56.6%of chloroplast lipid.Digalactosyldiacylglycerol(DGDG),monogalactosyldiacylglycerol(MGDG)and sulfoquinovosyldiacylglycerol(SQDG)were the main glyceroglycolipids.The fatty acyl R1/R2 were mostly 18:4/16:1,18:3/16:1 and 18:4/18:5 in DGDGs,14:0/18:4,18:4/18:5,18:4/18:4 and 18:3/18:4 in MGDGs and 16:0/14:0,16:0/18:3,and 18:4/18:3 in SQDGs.In addition,diacylglycerol(DAG)was the most abundant acylglycerols;the content of 22:6/18:4-DAG was the highest.There was a little amount of glycosphingolipid(GSL)in chloroplast.Digalactosylmonoglyceride(DGMG),monogalactosylmonoglyceride(MGMG),sulfoquinovosylmonoacylglycerol(SQMG),monoglyceride(MAG),phospholi-pids(PLs),ceramide(Cer)and betaine lipids were nearly undetectable in chloroplast.The fatty acid proportions of DGDGs,MGDGs,SQDGs,DAGs,triglycerides(TAGs)and GSLs were either higher or lower than or similar to those of whole-cell.Collectively,our isolation approach is applicable to many aspects of chloroplast biology,and may offer a reference for the isolation of chloroplasts from other marine microalgae.
基金This paper was published in Chinese in Acta Scientiae Circumstautiae,8(2),1988
文摘Effects of heavy metals on Isochrysis galbana (Parke ) were studied in our laboratory. The research focused on toxic effects of metals on algal cells, effects of water-soluble and lipid-soluble organic ligands on metal toxicity and processes of metal uptake by cells. Interactions between two metals and the mechanisms involved were also studied in detail. Finally, some relationships between toxicity and chemical property of metals were revealed.
