BACKGROUND Previous epidemiologic investigations have consistently demonstrated a strong association between the ratio of cholesterol to total lipids in medium very-lowdensity lipoprotein(VLDL)and the occurrence of pe...BACKGROUND Previous epidemiologic investigations have consistently demonstrated a strong association between the ratio of cholesterol to total lipids in medium very-lowdensity lipoprotein(VLDL)and the occurrence of peptic ulcers(PU).However,the precise causal relationship between these factors remains ambiguous.Consequently,this study aims to elucidate the potential correlation between the ratio of cholesterol to total lipids in medium VLDL and the incidence of peptic ulcer.AIM To investigate the ratio of cholesterol to total lipids in medium very-low-density lipoprotein(VLDL)association with PU via genetic methods,guiding future clinical research.METHODS Genome-wide association study(GWAS)datasets for the ratio of cholesterol to total lipids in intermediate VLDL and peptic ulcer were retrieved from the IEU OpenGWAS project(https://gwas.mrcieu.ac.uk).For the forward Mendelian randomization(MR)analysis,72 single nucleotide polymorphisms(SNPs)were identified as instrumental variables.These SNPs were selected based on their association with the ratio of cholesterol to total lipids in intermediate VLDL,with peptic ulcer as the outcome variable.Conversely,for the inverse MR analysis,no SNPs were identified with peptic ulcer as the exposure variable and the ratio of cholesterol to total lipids in intermediate VLDL as the outcome.All MR analyses utilized inverse variance weighted(IVW)as the primary analytical method.Additionally,weighted median and MR-Egger methods were employed as supplementary analytical approaches to assess causal effects.Egger regression was used as a supplementary method to evaluate potential directional pleiotropy.Heterogeneity and multiplicity tests were conducted using the leave-one-out method to evaluate result stability and mitigate biases associated with multiple testing.RESULTS The genetically predicted ratio of cholesterol to total lipids in medium VLDL was significantly associated with an elevated risk of peptic ulcer(IVW:OR=2.557,95%CI=1.274-5.132,P=0.008).However,no causal association of peptic ulcer with the ratio of cholesterol to total lipids in medium VLDL was observed in the inverse Mendelian randomization analysis.CONCLUSION In conclusion,our study reveals a significant association between the ratio of cholesterol to total lipids in medium VLDL and an elevated risk of peptic ulcers.However,further validation through laboratory investigations and larger-scale studies is warranted to strengthen the evidence and confirm the causal relationship between these factors.展开更多
Four strains of Cylindrotheca (B156, B164, B196, and B200) were harvested at three phases in the growth curve and their total lipid and fatty acid composition were determined. Total lipid reached highest values in the...Four strains of Cylindrotheca (B156, B164, B196, and B200) were harvested at three phases in the growth curve and their total lipid and fatty acid composition were determined. Total lipid reached highest values in the late stationary phase in B156 (24.0%), B164 (26.6%) and B200 (17.3%), in the exponential phase in B196 (15.5%). Saturated fatty acids increased with the development of the culture in B156 and B196, and reached their highest values in the late stationary phase in B156 (41.7%) and B196 (45.1%), in the early stationary phase in B164 (45.4%) and B200 (37.6%). Monounsaturated fatty acids increased with the development of the culture in B196 and B200, and reached their highest values in the late stationary phase in B196 (32.4%) and B200 (32.8%), in the early stationary phase in B164 (31.0%) and in the exponential phase in B156 (29.3%). Polyunsaturated fatty acids decreased in the later phases of the culture in B164, B196 and B200, and peaked in the exponential phase in B164 (29.5%), B196 (42.9%) and B200 (37.3%), and in the early stationary phase in B156 (32.0%).展开更多
Fatty acid composition and total lipid content of 8 strains of marine diatoms ( Nitzschia frustrula, Nitzschia closterium, Nitzschia incerta, Navicula pelliculosa,Phaeodactylum tricornutum, Synedra fragilaroides ) wer...Fatty acid composition and total lipid content of 8 strains of marine diatoms ( Nitzschia frustrula, Nitzschia closterium, Nitzschia incerta, Navicula pelliculosa,Phaeodactylum tricornutum, Synedra fragilaroides ) were examined. The microalgae were grown under defined conditions and harvested at the late exponential phase. The major fatty acids in most strains were 14:0 (1.0%-6.3%), 16:0 (13.5%-26.4%), 16:1n-7 (21.1%-46.3%) and 20:5n-3 (6.5%-19.5%). The polyunsaturated fatty acids 16:2n-4, 16:3n-4, 16:4n-1 and 20:4n-6 also comprised a significant proportion of the total fatty acids in some strains. The characteristic fatty acid composition of diatoms is readily distinguishable from those of other microalgal groups. Significant concentration of the polyunsaturated fatty acid 20:5n-3 (eicosapentaenoic acid) was present in each strain, with the highest proportion in B222 (19.5%).展开更多
The effect of light intensity (1500 lx and 5000 lx) on the total lipid and fatty acid composition of six strains of marine diatoms Cylindrotheca fusiformis (B211), Phaeodactylum tricornutum (B114, B118 and B221) Nitzs...The effect of light intensity (1500 lx and 5000 lx) on the total lipid and fatty acid composition of six strains of marine diatoms Cylindrotheca fusiformis (B211), Phaeodactylum tricornutum (B114, B118 and B221) Nitzschia closterium (B222) and Chaetoceros gracilis (B13) was investigated. The total lipids of B13, B114, and B211 grown at 5000 lx were lower than those grown at 1500 lx. No evident changes were observed in B118, B221 and B222. Fatty acid composition changed considerably at different light intensity although no consistent correlation between the relative proportion of a single FA and light intensity. The major fatty acids of the 6 strains were 14:0, 16:0, 16:1(n-7) and 20:5(n-3). Cylindrotheca fusiformis had high percentage of 20:4n-6 (9.2-10.9%). The total polyunsaturated fatty acid in all 6 strains decreased with increasing light intensity. The percentage of the highly unsaturated fatty acid eicosapentaenoic acid (EPA) decreased with increasing light intensity in all strains except Chaetoceros gracilis.展开更多
Nitrogen deficiency is an effective strategy for enhancing lipid production in microalgae. Close relationships exist among lipid production, microalgal species, and nitrogen sources. We report growth, lipid accumulati...Nitrogen deficiency is an effective strategy for enhancing lipid production in microalgae. Close relationships exist among lipid production, microalgal species, and nitrogen sources. We report growth, lipid accumulation, and fatty acid composition in four microalgae （Chloroeoccum ellipsoideum UTEX972, Chlorococcum nivale LB2225, Chlorococcum tatrense UTEX2227, and Scenedesmus deserticola JNU19） under nitrate- and urea-nitrogen deficiencies. We found three patterns of response to nitrogen deficiency： Type-A （decrease in biomass and increase in lipid content）, Type-B （reduction in both biomass and lipid content）, and Type-C （enhancement of both biomass and lipid content）. Type-C microalgae are potential candidates for large-scale oil production. Chlorococcum ellipsoideum, for example, exhibited a neutral lipid production of up to 239.6 mg/（L＇d） under urea-nitrogen deficiency. In addition, nitrogen deficiency showed only a slight influence on lipid fractions and fatty acid composition. Our study provides useful information for further screening hyper-lipid microalgal strains for biofuel production.展开更多
Microalgae Tetraselmis subcordiformis and Nannochloropsis oculata were cultured at 15,20,25,30,and 35℃ and their properties as potential biofuel resources were examined.The results indicate that T.subcordiformis and ...Microalgae Tetraselmis subcordiformis and Nannochloropsis oculata were cultured at 15,20,25,30,and 35℃ and their properties as potential biofuel resources were examined.The results indicate that T.subcordiformis and N.oculata grew best at 20℃ and 25℃ and yielded the highest total lipids at 20℃and 30℃,respectively.With increased temperature,neutral lipid and polyunsaturated fatty acids(FAs)decreased while saturated FAs increased,accompanied by increased monounsaturated FAs(MUFAs) in T.subcordiformis and decreased MUFAs in N.oculata;meanwhile,the predicted cetane number of FA methyl esters increased from 45.3 to 47.6 in T.subcordiformis and from 52.3 to 60.3 in N.oculata.Therefore,optimizing culture temperatures is important for improving microalgal biodiesel production.展开更多
A diatom was purified with colony selection and continuous dilution methods. It was identified to Cylindrotheca closterium according to its morphological characteristics and rbc L and 18 s r RNA gene sequences. The al...A diatom was purified with colony selection and continuous dilution methods. It was identified to Cylindrotheca closterium according to its morphological characteristics and rbc L and 18 s r RNA gene sequences. The alga was not sensitive to ampicillin and neomycin, but sensitive to chloramphenicol which inhibited its growth at concentrations ranging from 50 to 150 μg m L-1. The purified alga was easy to culture and its specific growth rate was 0.207 ± 0.002(d-1). It was resistant to pollution and could be harvested in an easy way. It was relatively high in lipid content(20.08% ± 0.67% of dry weight) and the combined amount of its 16:0 and 16:1(n-7), the most suitable resource of biodiesel, was as high as 64% of the total fatty acids, while the amount of polyunsaturated fatty acids reached 19.96%–20% of the total fatty acids. Thus the purified C. closterium can be cultured as a biodiesel producer or a nutrition supplement producer.展开更多
Emiliania huxleyi is the most prominent modern coccolithophore,a group of marine unicellular eukaryotes that play a critical role in ocean biogeochemistry.Coccolithoviruses are large double stranded DNA viruses,which ...Emiliania huxleyi is the most prominent modern coccolithophore,a group of marine unicellular eukaryotes that play a critical role in ocean biogeochemistry.Coccolithoviruses are large double stranded DNA viruses,which is responsible for the demise of large oceanic blooms formed by E.huxleyi.E.huxleyi virus(EhVs)acquired a series of enzyme-coding genes predicted to be involved in the sphingolipid biosynthesis by horizontal gene transfer between virus-host.Currently,there is limited experimental validation identifying the functions of these genes in EhV.Genetic transformation of eukaryotic cells is a powerful tool to get an insight into gene functions of the studied organisms.Serine palmitoyltransferase(SPT)catalyzes the first committed step in de novo sphingolipid biosynthetic pathway.Here,a novel vector system for the transformation of E.huxleyi was designed.It contained fragments of promoter and terminator sequences of E.huxleyi endogenic fucoxanthin chlorophyll a/c-binding protein gene“fcp”and harbored EhV-99B1 spt gene.The resultant recombinant transformation vectors pEhux-I-spt and pEhux-II were co-transferred into E.huxleyi BOF92 by electroporation.Transformants were obtained upon glufosinate-ammonium selection,and confirmed by Southern hybridization,genome PCR,qRT-PCR and Western blot screening of spt gene,which indicated that spt gene was integrated into the nuclear genome and was expressed at the mRNA and protein levels.The expression of the viral spt gene led to differences in lipid compositions analyzed using thin-layer chromatography(TLC).The results present the genetic transformation system for E.huxleyi,providing additional genetic resource with potential for exploring basic biological questions such as the virus-host interactions.展开更多
Objective:To identify the alleralinn of the membrane polenlial and llie effect of carolenoid extracts from Chlorococcum hnmicola(C.humicola) on membrane hound ATPases and lipid peroxidation.Methods:The lolal carotenoi...Objective:To identify the alleralinn of the membrane polenlial and llie effect of carolenoid extracts from Chlorococcum hnmicola(C.humicola) on membrane hound ATPases and lipid peroxidation.Methods:The lolal carotenoids were extracted from C.humicola.Four groups of Swiss albino mice were treated as control,Benzo(a)pyrene[B(a)P],total carotenoids,B(a)P+ total caralenoids respectively for a period of 60 days.Membrane lipid peroxidation and ATPases(Total ATPases,Ca^(2+)-ATPases.Mg^(2+)-ATPases.Na^+K^+- ATPasei were determined in lung,liver and erythrocyte samples.Results:The activity of lolal ATPase was found to be significantly increased in the B(a)P treated liver and lung tissue.Erythrocyte membrane also showed higher ATPase activity which was significantly reverted on total carolenoid treatment.Conclusions: It can be concluded that the changes in membrane potential favour the functional deterioration of physiological system.The overall findings demonstrates that the animals post treated with carolenoid extract from C.humicola may maintains the alterations in membrane bound ATPase and lipid peroxidation in tissues against the carcinogenic chemical and hence aid in establishing the membrane potential action.Then-fore C.humicola can be further extended to exploits its possible application for various health benefits as neulraceulicals and food additives.展开更多
文摘BACKGROUND Previous epidemiologic investigations have consistently demonstrated a strong association between the ratio of cholesterol to total lipids in medium very-lowdensity lipoprotein(VLDL)and the occurrence of peptic ulcers(PU).However,the precise causal relationship between these factors remains ambiguous.Consequently,this study aims to elucidate the potential correlation between the ratio of cholesterol to total lipids in medium VLDL and the incidence of peptic ulcer.AIM To investigate the ratio of cholesterol to total lipids in medium very-low-density lipoprotein(VLDL)association with PU via genetic methods,guiding future clinical research.METHODS Genome-wide association study(GWAS)datasets for the ratio of cholesterol to total lipids in intermediate VLDL and peptic ulcer were retrieved from the IEU OpenGWAS project(https://gwas.mrcieu.ac.uk).For the forward Mendelian randomization(MR)analysis,72 single nucleotide polymorphisms(SNPs)were identified as instrumental variables.These SNPs were selected based on their association with the ratio of cholesterol to total lipids in intermediate VLDL,with peptic ulcer as the outcome variable.Conversely,for the inverse MR analysis,no SNPs were identified with peptic ulcer as the exposure variable and the ratio of cholesterol to total lipids in intermediate VLDL as the outcome.All MR analyses utilized inverse variance weighted(IVW)as the primary analytical method.Additionally,weighted median and MR-Egger methods were employed as supplementary analytical approaches to assess causal effects.Egger regression was used as a supplementary method to evaluate potential directional pleiotropy.Heterogeneity and multiplicity tests were conducted using the leave-one-out method to evaluate result stability and mitigate biases associated with multiple testing.RESULTS The genetically predicted ratio of cholesterol to total lipids in medium VLDL was significantly associated with an elevated risk of peptic ulcer(IVW:OR=2.557,95%CI=1.274-5.132,P=0.008).However,no causal association of peptic ulcer with the ratio of cholesterol to total lipids in medium VLDL was observed in the inverse Mendelian randomization analysis.CONCLUSION In conclusion,our study reveals a significant association between the ratio of cholesterol to total lipids in medium VLDL and an elevated risk of peptic ulcers.However,further validation through laboratory investigations and larger-scale studies is warranted to strengthen the evidence and confirm the causal relationship between these factors.
文摘Four strains of Cylindrotheca (B156, B164, B196, and B200) were harvested at three phases in the growth curve and their total lipid and fatty acid composition were determined. Total lipid reached highest values in the late stationary phase in B156 (24.0%), B164 (26.6%) and B200 (17.3%), in the exponential phase in B196 (15.5%). Saturated fatty acids increased with the development of the culture in B156 and B196, and reached their highest values in the late stationary phase in B156 (41.7%) and B196 (45.1%), in the early stationary phase in B164 (45.4%) and B200 (37.6%). Monounsaturated fatty acids increased with the development of the culture in B196 and B200, and reached their highest values in the late stationary phase in B196 (32.4%) and B200 (32.8%), in the early stationary phase in B164 (31.0%) and in the exponential phase in B156 (29.3%). Polyunsaturated fatty acids decreased in the later phases of the culture in B164, B196 and B200, and peaked in the exponential phase in B164 (29.5%), B196 (42.9%) and B200 (37.3%), and in the early stationary phase in B156 (32.0%).
基金Project supported by the Hi-Tech“863”Programs of the China Ministry of Science and Technology(863-819-02-01).
文摘Fatty acid composition and total lipid content of 8 strains of marine diatoms ( Nitzschia frustrula, Nitzschia closterium, Nitzschia incerta, Navicula pelliculosa,Phaeodactylum tricornutum, Synedra fragilaroides ) were examined. The microalgae were grown under defined conditions and harvested at the late exponential phase. The major fatty acids in most strains were 14:0 (1.0%-6.3%), 16:0 (13.5%-26.4%), 16:1n-7 (21.1%-46.3%) and 20:5n-3 (6.5%-19.5%). The polyunsaturated fatty acids 16:2n-4, 16:3n-4, 16:4n-1 and 20:4n-6 also comprised a significant proportion of the total fatty acids in some strains. The characteristic fatty acid composition of diatoms is readily distinguishable from those of other microalgal groups. Significant concentration of the polyunsaturated fatty acid 20:5n-3 (eicosapentaenoic acid) was present in each strain, with the highest proportion in B222 (19.5%).
文摘The effect of light intensity (1500 lx and 5000 lx) on the total lipid and fatty acid composition of six strains of marine diatoms Cylindrotheca fusiformis (B211), Phaeodactylum tricornutum (B114, B118 and B221) Nitzschia closterium (B222) and Chaetoceros gracilis (B13) was investigated. The total lipids of B13, B114, and B211 grown at 5000 lx were lower than those grown at 1500 lx. No evident changes were observed in B118, B221 and B222. Fatty acid composition changed considerably at different light intensity although no consistent correlation between the relative proportion of a single FA and light intensity. The major fatty acids of the 6 strains were 14:0, 16:0, 16:1(n-7) and 20:5(n-3). Cylindrotheca fusiformis had high percentage of 20:4n-6 (9.2-10.9%). The total polyunsaturated fatty acid in all 6 strains decreased with increasing light intensity. The percentage of the highly unsaturated fatty acid eicosapentaenoic acid (EPA) decreased with increasing light intensity in all strains except Chaetoceros gracilis.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(Nos.2009AA064401,2013AA065805)the National Natural Science Foundation of China(Nos.31170337,41176105)the National Basic Research Program of China(973 Program)(No.2011CB2009001)
文摘Nitrogen deficiency is an effective strategy for enhancing lipid production in microalgae. Close relationships exist among lipid production, microalgal species, and nitrogen sources. We report growth, lipid accumulation, and fatty acid composition in four microalgae （Chloroeoccum ellipsoideum UTEX972, Chlorococcum nivale LB2225, Chlorococcum tatrense UTEX2227, and Scenedesmus deserticola JNU19） under nitrate- and urea-nitrogen deficiencies. We found three patterns of response to nitrogen deficiency： Type-A （decrease in biomass and increase in lipid content）, Type-B （reduction in both biomass and lipid content）, and Type-C （enhancement of both biomass and lipid content）. Type-C microalgae are potential candidates for large-scale oil production. Chlorococcum ellipsoideum, for example, exhibited a neutral lipid production of up to 239.6 mg/（L＇d） under urea-nitrogen deficiency. In addition, nitrogen deficiency showed only a slight influence on lipid fractions and fatty acid composition. Our study provides useful information for further screening hyper-lipid microalgal strains for biofuel production.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2009AA064401)the Special Fundation for Marine Renewable Energy from the State Oceanic Administration of China(No.SHME2011SW02)the Shanghai Universities First-class Disciplines Project of Fisheries(A)
文摘Microalgae Tetraselmis subcordiformis and Nannochloropsis oculata were cultured at 15,20,25,30,and 35℃ and their properties as potential biofuel resources were examined.The results indicate that T.subcordiformis and N.oculata grew best at 20℃ and 25℃ and yielded the highest total lipids at 20℃and 30℃,respectively.With increased temperature,neutral lipid and polyunsaturated fatty acids(FAs)decreased while saturated FAs increased,accompanied by increased monounsaturated FAs(MUFAs) in T.subcordiformis and decreased MUFAs in N.oculata;meanwhile,the predicted cetane number of FA methyl esters increased from 45.3 to 47.6 in T.subcordiformis and from 52.3 to 60.3 in N.oculata.Therefore,optimizing culture temperatures is important for improving microalgal biodiesel production.
基金supported by the Major State Basic Research Development Program of China (973 Program) (2011CB200901)National Technical Supporting Project Foundation (2011BAD14B01)Energy Project from State Bureau of Oceanic Administration (Grant No. GHME2011SW03)
文摘A diatom was purified with colony selection and continuous dilution methods. It was identified to Cylindrotheca closterium according to its morphological characteristics and rbc L and 18 s r RNA gene sequences. The alga was not sensitive to ampicillin and neomycin, but sensitive to chloramphenicol which inhibited its growth at concentrations ranging from 50 to 150 μg m L-1. The purified alga was easy to culture and its specific growth rate was 0.207 ± 0.002(d-1). It was resistant to pollution and could be harvested in an easy way. It was relatively high in lipid content(20.08% ± 0.67% of dry weight) and the combined amount of its 16:0 and 16:1(n-7), the most suitable resource of biodiesel, was as high as 64% of the total fatty acids, while the amount of polyunsaturated fatty acids reached 19.96%–20% of the total fatty acids. Thus the purified C. closterium can be cultured as a biodiesel producer or a nutrition supplement producer.
基金Supported by the National Natural Science Foundation of China(Nos.41576166,21707042,31771972)the Fujian Province Natural Science Foundation of China(Nos.2019J01696,2017J01447,2017J01636)。
文摘Emiliania huxleyi is the most prominent modern coccolithophore,a group of marine unicellular eukaryotes that play a critical role in ocean biogeochemistry.Coccolithoviruses are large double stranded DNA viruses,which is responsible for the demise of large oceanic blooms formed by E.huxleyi.E.huxleyi virus(EhVs)acquired a series of enzyme-coding genes predicted to be involved in the sphingolipid biosynthesis by horizontal gene transfer between virus-host.Currently,there is limited experimental validation identifying the functions of these genes in EhV.Genetic transformation of eukaryotic cells is a powerful tool to get an insight into gene functions of the studied organisms.Serine palmitoyltransferase(SPT)catalyzes the first committed step in de novo sphingolipid biosynthetic pathway.Here,a novel vector system for the transformation of E.huxleyi was designed.It contained fragments of promoter and terminator sequences of E.huxleyi endogenic fucoxanthin chlorophyll a/c-binding protein gene“fcp”and harbored EhV-99B1 spt gene.The resultant recombinant transformation vectors pEhux-I-spt and pEhux-II were co-transferred into E.huxleyi BOF92 by electroporation.Transformants were obtained upon glufosinate-ammonium selection,and confirmed by Southern hybridization,genome PCR,qRT-PCR and Western blot screening of spt gene,which indicated that spt gene was integrated into the nuclear genome and was expressed at the mRNA and protein levels.The expression of the viral spt gene led to differences in lipid compositions analyzed using thin-layer chromatography(TLC).The results present the genetic transformation system for E.huxleyi,providing additional genetic resource with potential for exploring basic biological questions such as the virus-host interactions.
基金Supported by Bharathiar university.coimbatore,Tamilnadu India
文摘Objective:To identify the alleralinn of the membrane polenlial and llie effect of carolenoid extracts from Chlorococcum hnmicola(C.humicola) on membrane hound ATPases and lipid peroxidation.Methods:The lolal carotenoids were extracted from C.humicola.Four groups of Swiss albino mice were treated as control,Benzo(a)pyrene[B(a)P],total carotenoids,B(a)P+ total caralenoids respectively for a period of 60 days.Membrane lipid peroxidation and ATPases(Total ATPases,Ca^(2+)-ATPases.Mg^(2+)-ATPases.Na^+K^+- ATPasei were determined in lung,liver and erythrocyte samples.Results:The activity of lolal ATPase was found to be significantly increased in the B(a)P treated liver and lung tissue.Erythrocyte membrane also showed higher ATPase activity which was significantly reverted on total carolenoid treatment.Conclusions: It can be concluded that the changes in membrane potential favour the functional deterioration of physiological system.The overall findings demonstrates that the animals post treated with carolenoid extract from C.humicola may maintains the alterations in membrane bound ATPase and lipid peroxidation in tissues against the carcinogenic chemical and hence aid in establishing the membrane potential action.Then-fore C.humicola can be further extended to exploits its possible application for various health benefits as neulraceulicals and food additives.
