Compositions of glycerolipids and fatty acid compositions of glycerolipids were compared among Synechocystis sp. PCC 6803 cells grown in the BG-11 medium containing different concentrations of glucose and Na2S2O3 in t...Compositions of glycerolipids and fatty acid compositions of glycerolipids were compared among Synechocystis sp. PCC 6803 cells grown in the BG-11 medium containing different concentrations of glucose and Na2S2O3 in this study. It was found that Na2S2O3 can effectively increase the percentage of sulphoquinovosyl diacylglycerol (SQDG) and phosphatidylglycerol (PG) to total membrane lipids and the simultaneous application of glucose with Na2S2O3 can counteract the effect of Na2S2O3. In addition, Na2S2O3 can significantly increase the percentage of palmitic acid (C, 16:0) in fatty acid composition of monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG) and decrease the fatty acid unsaturation degree accordingly, and these effects can also be eliminated by glucose. These results indicate that Na2S2O3 can take as a reductant to make membrane lipids in a low unsaturated state, and the simultaneous application of glucose can decrease the reducing power of Na2S2O3. In addition, Na2S2O3 can take as a sulfur donor for the synthesis of SQDG.展开更多
Plastidial ω-3 desaturase FAD7 is a major contributor to trienoic fatty acid biosynthesis in the leaves of Arabidopsis plants. However, the precise contribution of the other plastidial ω-3 desaturase, FAD8, is poorl...Plastidial ω-3 desaturase FAD7 is a major contributor to trienoic fatty acid biosynthesis in the leaves of Arabidopsis plants. However, the precise contribution of the other plastidial ω-3 desaturase, FAD8, is poorly understood. Fatty acid and lipid analysis of several ω-3 desaturase mutants, including two insertion lines of AtFAD7 and AtFAD8, showed that FAD8 partially compensated the disruption of the AtFAD7 gene at 22℃, indicating that FAD8 was active at this growth temperature, contrasting to previous observations that circumscribed the FAD8 activity at low temperatures. Our data revealed that FAD8 had a higher selectivity for 18：2 acyl-lipid substrates and a higher preference for lipids other than galactolipids, particularly phosphatidylglycerol, at any of the temperatures studied. Differences in the mechanism controlling AtFAD7 and AtFAD8 gene expression at different temperatures were also detected. Confocal microscopy and biochemical analysis of FAD8-YFP over-expressing lines confirmed the chloroplast envelope localization of FAD8. Co-localization experiments suggested that FAD8 and FAD7 might be located in close vicinity in the envelope membrane. FAD8-YFP over-expressing lines showed a specific increase in 18：3 fatty acids at 22℃. Together, these results indicate that the function of both plastidial ω-3 desaturases is coordinated in a non-redundant manner.展开更多
The biosynthesis of glycolipids in E.fascicula-tus was studied by 14C label and chase. The fatty acids in sulphoquinovosyl diacylglycerol (SQDG) were almost 16-car-bon and 18-carbon ones. In addition to the two fatty ...The biosynthesis of glycolipids in E.fascicula-tus was studied by 14C label and chase. The fatty acids in sulphoquinovosyl diacylglycerol (SQDG) were almost 16-car-bon and 18-carbon ones. In addition to the two fatty acids, monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG) contained 8.5 mol% and 31.0 mol% of eicosapentaenoic acid (20 : 5), respectively, and this fatty acid was usually distributed in the sn-1 position of the glyc-erol backbone. When plants were incubated with [2-14C] acetate, differences existed in the positional distribution of the labeled fatty acids in sn-1 and sn-2 among the three glycerolipids. In SQDG, 14C-labeled fatty acids were distributed uniformly in the sn-1 and sn-2 positions. In DGDG, 14C-labeled fatty acids were mainly distributed in the sn-2 position. In MGDG, the radioactivity of fatty acids in sn-1 position was far greater than that in sn-2 position after a 30 min pulse label, and the difference in radioactivity between the two positions展开更多
Yellow sarson(Brassica rapa ssp. trillocularis) is an important rapeseed-mustard species of Brassica rapa due to its high seed oil content. Glycerolipids and fatty acid composition affect seed germination and determin...Yellow sarson(Brassica rapa ssp. trillocularis) is an important rapeseed-mustard species of Brassica rapa due to its high seed oil content. Glycerolipids and fatty acid composition affect seed germination and determine the quality of seed oil. To date, no information is available on the composition of individual glycerolipids in this species. Therefore, in this study the glycerolipid profiling of yellow sarson seeds was performed using ultra high performance liquid chromatography coupled to triple time-of-flight mass spectrometry(UPLC-Triple-TOF-MS).A fast and efficient chromatographic separation of glycerolipids was accomplished based on an UPLCTMBEH C8 column within 22 min.In ESI positive ion mode, TOF-MS scan-information dependent acquisition-product ion scan was carried out to acquire both high resolution MS and MS/MS information from one injection. According to MS/MS spectra, predominant fragmentation patterns of glycerolipids were elucidated in detail. Based on retention time, accurate mass, isotopic distribution, and fragmentation patterns, the composition of 144 glycerolipids and fatty acids were finally identified in yellow sarson seeds, including 77 triacylglycerols, 32 diacylglycerols, 18sulfoquinovosyl-diacylglycerols, 5 monogalactosyl-diaclyglycerols, and 12 digalactosyl-diacylglycerols. Of them, the most abundant glycerolipids in yellow sarson seeds were triacylglycerols, the major storage form of seed oil in plants. In addition, diacylglycerols were found as a minor component of glycerolipids. The lowest amounts of glycerolipids detected in seeds were glycosyl-acylglycerols. The results revealed the composition and relative content of glycerolipids in yellow sarson seeds, which will provide a more comprehensive assessment of the quality of seed oil and also help to select functional cultivars with higher beneficial glycerolipids. This profiling method has the advantages of high throughput, high sensitivity and good accuracy, which will provide a reliable analysis platform for glycerolipids metabolism in plants.展开更多
Precise structural identification of photosynthetic polar glycerolipids in microalga Tetraselmis chuii has been established using Ultra Performance Liquid Chromatography–Electrospray ionization-Quadrupole-Time of Fli...Precise structural identification of photosynthetic polar glycerolipids in microalga Tetraselmis chuii has been established using Ultra Performance Liquid Chromatography–Electrospray ionization-Quadrupole-Time of Flight Mass Spectrometry(UPLC-ESI-Q-TOF-MS)by direct analysis of the total lipids extract.The mass spectrometry was performed in reflective time-of-flight using electron spraying ionization in both positive and negative modes.The structural determination was based on the char-acteristic product ions yielded by different glycerolipids under ESI-MS/MS mode,and confirmed the molecular species by the carboxylate anions produced by glycerolipids in the negative mode.As a result,more than 40 lipid molecular species,including 11 monogalactosyldiacylglycerols(MGDG),7 digalactosyldiacylglycerols(DGDG),16 sulfoquinovosyldiacylglycerols(SQDG),and 9 phosphatidyl-glycerols(PG),were detected in Tetraselmis chuii,which had never been identified before in this mi-croalga.Furthermore,some intact lipid molecules with hydroxylated fatty acids that could not be de-tected by the traditional GC-MS method were found this time,providing novel information for the pho-tosynthetic lipidome of Tetraselmis chuii.Comparative studies on fatty acids at the sn-2 position showed that SQDG and MGDG are dominantly biosynthesized through the prokaryotic pathway,PG is a typically mixed biosynthetic pathway,while DGDG is somewhat peculiar with C14:0 and C16:0 at its sn-2 position.This method could provide a full structural profile of intact photosynthetic lipid molecular species,which may be applied to study the physiological and ecological functions of lipid by monitor-ing their individual changes.展开更多
文摘Compositions of glycerolipids and fatty acid compositions of glycerolipids were compared among Synechocystis sp. PCC 6803 cells grown in the BG-11 medium containing different concentrations of glucose and Na2S2O3 in this study. It was found that Na2S2O3 can effectively increase the percentage of sulphoquinovosyl diacylglycerol (SQDG) and phosphatidylglycerol (PG) to total membrane lipids and the simultaneous application of glucose with Na2S2O3 can counteract the effect of Na2S2O3. In addition, Na2S2O3 can significantly increase the percentage of palmitic acid (C, 16:0) in fatty acid composition of monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG) and decrease the fatty acid unsaturation degree accordingly, and these effects can also be eliminated by glucose. These results indicate that Na2S2O3 can take as a reductant to make membrane lipids in a low unsaturated state, and the simultaneous application of glucose can decrease the reducing power of Na2S2O3. In addition, Na2S2O3 can take as a sulfur donor for the synthesis of SQDG.
文摘Plastidial ω-3 desaturase FAD7 is a major contributor to trienoic fatty acid biosynthesis in the leaves of Arabidopsis plants. However, the precise contribution of the other plastidial ω-3 desaturase, FAD8, is poorly understood. Fatty acid and lipid analysis of several ω-3 desaturase mutants, including two insertion lines of AtFAD7 and AtFAD8, showed that FAD8 partially compensated the disruption of the AtFAD7 gene at 22℃, indicating that FAD8 was active at this growth temperature, contrasting to previous observations that circumscribed the FAD8 activity at low temperatures. Our data revealed that FAD8 had a higher selectivity for 18：2 acyl-lipid substrates and a higher preference for lipids other than galactolipids, particularly phosphatidylglycerol, at any of the temperatures studied. Differences in the mechanism controlling AtFAD7 and AtFAD8 gene expression at different temperatures were also detected. Confocal microscopy and biochemical analysis of FAD8-YFP over-expressing lines confirmed the chloroplast envelope localization of FAD8. Co-localization experiments suggested that FAD8 and FAD7 might be located in close vicinity in the envelope membrane. FAD8-YFP over-expressing lines showed a specific increase in 18：3 fatty acids at 22℃. Together, these results indicate that the function of both plastidial ω-3 desaturases is coordinated in a non-redundant manner.
基金This work was supportedby the National Natural Science Foundation of China (Grant No. 39890390), the One-Hundred-Scientist Program of the Chinese Academy of Sciences, the State Basic Research Development Plan of China (Grant No. G1998010100) and the I
文摘The biosynthesis of glycolipids in E.fascicula-tus was studied by 14C label and chase. The fatty acids in sulphoquinovosyl diacylglycerol (SQDG) were almost 16-car-bon and 18-carbon ones. In addition to the two fatty acids, monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG) contained 8.5 mol% and 31.0 mol% of eicosapentaenoic acid (20 : 5), respectively, and this fatty acid was usually distributed in the sn-1 position of the glyc-erol backbone. When plants were incubated with [2-14C] acetate, differences existed in the positional distribution of the labeled fatty acids in sn-1 and sn-2 among the three glycerolipids. In SQDG, 14C-labeled fatty acids were distributed uniformly in the sn-1 and sn-2 positions. In DGDG, 14C-labeled fatty acids were mainly distributed in the sn-2 position. In MGDG, the radioactivity of fatty acids in sn-1 position was far greater than that in sn-2 position after a 30 min pulse label, and the difference in radioactivity between the two positions
基金supported by the National Risk Assessment Project for the Project of Risk Assessment on Vegetable Products (GJFP2017002)the Basic Scientific Research Project of Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences (1610102016023)
文摘Yellow sarson(Brassica rapa ssp. trillocularis) is an important rapeseed-mustard species of Brassica rapa due to its high seed oil content. Glycerolipids and fatty acid composition affect seed germination and determine the quality of seed oil. To date, no information is available on the composition of individual glycerolipids in this species. Therefore, in this study the glycerolipid profiling of yellow sarson seeds was performed using ultra high performance liquid chromatography coupled to triple time-of-flight mass spectrometry(UPLC-Triple-TOF-MS).A fast and efficient chromatographic separation of glycerolipids was accomplished based on an UPLCTMBEH C8 column within 22 min.In ESI positive ion mode, TOF-MS scan-information dependent acquisition-product ion scan was carried out to acquire both high resolution MS and MS/MS information from one injection. According to MS/MS spectra, predominant fragmentation patterns of glycerolipids were elucidated in detail. Based on retention time, accurate mass, isotopic distribution, and fragmentation patterns, the composition of 144 glycerolipids and fatty acids were finally identified in yellow sarson seeds, including 77 triacylglycerols, 32 diacylglycerols, 18sulfoquinovosyl-diacylglycerols, 5 monogalactosyl-diaclyglycerols, and 12 digalactosyl-diacylglycerols. Of them, the most abundant glycerolipids in yellow sarson seeds were triacylglycerols, the major storage form of seed oil in plants. In addition, diacylglycerols were found as a minor component of glycerolipids. The lowest amounts of glycerolipids detected in seeds were glycosyl-acylglycerols. The results revealed the composition and relative content of glycerolipids in yellow sarson seeds, which will provide a more comprehensive assessment of the quality of seed oil and also help to select functional cultivars with higher beneficial glycerolipids. This profiling method has the advantages of high throughput, high sensitivity and good accuracy, which will provide a reliable analysis platform for glycerolipids metabolism in plants.
基金Supported by the Program for Changjiang Scholars and Innovative Research Team in Universities(PCSIRT)(Grant No.IRT0734)Project of National Ocean Bureau(Grant No.200805067)+1 种基金Project of Ministry of Science and Technology(Grant No.2007BAD43B09)K.C.Wong Magna Fund in Ningbo University
文摘Precise structural identification of photosynthetic polar glycerolipids in microalga Tetraselmis chuii has been established using Ultra Performance Liquid Chromatography–Electrospray ionization-Quadrupole-Time of Flight Mass Spectrometry(UPLC-ESI-Q-TOF-MS)by direct analysis of the total lipids extract.The mass spectrometry was performed in reflective time-of-flight using electron spraying ionization in both positive and negative modes.The structural determination was based on the char-acteristic product ions yielded by different glycerolipids under ESI-MS/MS mode,and confirmed the molecular species by the carboxylate anions produced by glycerolipids in the negative mode.As a result,more than 40 lipid molecular species,including 11 monogalactosyldiacylglycerols(MGDG),7 digalactosyldiacylglycerols(DGDG),16 sulfoquinovosyldiacylglycerols(SQDG),and 9 phosphatidyl-glycerols(PG),were detected in Tetraselmis chuii,which had never been identified before in this mi-croalga.Furthermore,some intact lipid molecules with hydroxylated fatty acids that could not be de-tected by the traditional GC-MS method were found this time,providing novel information for the pho-tosynthetic lipidome of Tetraselmis chuii.Comparative studies on fatty acids at the sn-2 position showed that SQDG and MGDG are dominantly biosynthesized through the prokaryotic pathway,PG is a typically mixed biosynthetic pathway,while DGDG is somewhat peculiar with C14:0 and C16:0 at its sn-2 position.This method could provide a full structural profile of intact photosynthetic lipid molecular species,which may be applied to study the physiological and ecological functions of lipid by monitor-ing their individual changes.
