As more and more studies have shown that lipid molecules play an important role in the whole biology,in-depth analysis of lipid structure has become particularly important in lipidomics.Mass spectrometry(MS),as the pr...As more and more studies have shown that lipid molecules play an important role in the whole biology,in-depth analysis of lipid structure has become particularly important in lipidomics.Mass spectrometry(MS),as the preferred tool for lipid analysis,has greatly promoted the development of this field.However,the existing MS methods still face many difficulties in the in-depth or even comprehensive analysis of lipid structure.In this review,we discuss recent advances in MS methods based on double bond-specific chemistries for the resolving of C=C location and geometry isomers of lipids.This progress has greatly advanced the lipidomics analysis to a deeper structural level and facilitated the development of structural lipid biology.展开更多
Various chemical and gas-liquid chromatographic analyses indicate that the lipid A,backbone of the lipopolysaccharide(LPS)isolated from B.fragilis NCTC 9343 is chemically con-stitutεd by a β1,6-interlinked D-glucosa...Various chemical and gas-liquid chromatographic analyses indicate that the lipid A,backbone of the lipopolysaccharide(LPS)isolated from B.fragilis NCTC 9343 is chemically con-stitutεd by a β1,6-interlinked D-glucosamine disaccharide.It is phosphorylated at its 1-positionby a glvcosidic-linkage while the ester-linked phosphate at 4’—position present generally in otherlipid A is depleted.The lipid A is lower fatty acylated in the amount of 5.2 fatty acids/lipid Amolecule(of which 0.73 forms 3-acyloxyacyl groups).The LPS containing such an incompletelipid A component has been shown endowina with a weaker endotoxicitv.展开更多
Peculiar properties of morphological structures of organelle membranes were studied by fluorescent confocal microscopy. The list of objects in our experiments was represented by mitochondria, chloroplasts and vacuoles...Peculiar properties of morphological structures of organelle membranes were studied by fluorescent confocal microscopy. The list of objects in our experiments was represented by mitochondria, chloroplasts and vacuoles. During this study, identification of lipid microinclusions having the form of such lipid-protein structural microformations as lipid-protein microdomains, vesicles and membrane tubular structures (cytoplasmic transvacuolar strands and nanotubes) located in organelle membranes or bound up with them was conducted. Such membrane probes as laurdan, DPH, ANS and bis-ANS were used. Comparison of fluorescence intensity of these membrane probes was conducted. This investigation of the morphological properties of lipid-protein structural microformations was accompanied with analysis of 1) the phase state and 2) dynamics of microviscosity variations in the membrane elements of isolated plant cell organelles. Distributions of laurdan fluorescence generalized polarization (GP) values for the membrane on the whole and for the intensively fluorescing membrane segments were obtained. It was discovered that the microviscosity of intensively fluorescing membrane segments essentially differed from the microviscosity of the rest part of the membrane. In conclusion, some results of the study of peculiar properties of lipid-protein structural microformations related to the structure of organelle membranes and the discoveries made in this investigation are discussed.展开更多
The normal development and maintenance of central neural functions are highly correlated with the amount of docosahexaenoic acid(DHA;ω-3 fatty acid)accumulated in the brain.DHA incorporated at the sn-2 position of li...The normal development and maintenance of central neural functions are highly correlated with the amount of docosahexaenoic acid(DHA;ω-3 fatty acid)accumulated in the brain.DHA incorporated at the sn-2 position of lipids is well absorbed by intestinal mucosa and utilized efficiently in vivo.However,modern consumers have a reduced direct intake of DHA and increased intake of saturated fats or ω-6 fatty acid oils,resulting in behavioral and neurophysiological deficits.To provide an understanding of the integrated beneficial effects of DHA on the human brain,this review introduces the positional difference(sn-2 and sn-1,3 positions)of DHA on a glycerol skeleton in natural fats and oils,and further discusses the possible functional mechanism regarding DHA supplementation and the gut-brain axis.The multiple bidirectional routes in this axis offer a novel insight into the interaction between DHA supplementation,the gut microbiota,and brain health.To achieve high sn-2 DHA in diets,it is suggested that sn-2 DHA lipids be enzymatically produced in more efficient and economical ways by improving the specific activities of lipases and optimizing the purification procedures.These types of diets will benefit individuals with strong needs for sn-2 ω-3 lipids such as infants,children,and pregnant and lactating women.展开更多
Experiments were conducted to study the effects of selenium (Se) on glutathione peroxidase(GSH-Px) activity and the accumulation of malonaldehyde(MDA),the product of lipid peroxidation in soybean seedling, as well as ...Experiments were conducted to study the effects of selenium (Se) on glutathione peroxidase(GSH-Px) activity and the accumulation of malonaldehyde(MDA),the product of lipid peroxidation in soybean seedling, as well as the effect of Se on cell ultra structure of soybean leaf and nascent root under salt stress. Results showed that appropriate amount of Se addition increased GSH-Px activity in soybean leaves from 0. 810 to 1. 421μmol·g-1 fresh weight·min-1 F = 9.12, and reduced the concentration of MDA from 20.17 to 16.16 μmol·g-1 fresh weight, F = 5.44. Under salt stress,no obvious damage on chloplast membrane was observed in Se treated seedlings,and the structures of chloplast and mitochondrion were integrate,whereas in control (no Se addition),the cell membrane was destroyed seriously,chloplast degraded and mitochondrion disappeared. Compared with control,Se addition increased the dry matter weight of seedling by 2.92% to 21.86%, F =5.97.展开更多
Lipids possess a wide range of biological activities in plants, animals and humans. They also serve as important components of our daily diet and provide both energy and essential fatty acids;they also act as carriers...Lipids possess a wide range of biological activities in plants, animals and humans. They also serve as important components of our daily diet and provide both energy and essential fatty acids;they also act as carriers of fat-soluble vitamins and help in their absorption. Lipids are crucial as a heating medium for food processing and affect the texture, mouth feel and flavour of foods. Structured lipids (SL) are triacylglycerols (TAG) modified to alter the fatty acid composition and/or their location in the glycerol backbone via chemical or enzymatic means. SL may offer the most efficient means of delivering target fatty acids for nutritive or therapeutic purposes as well as to alleviate specific disease and metabolic conditions. This document discusses chemistry, composition, classification, function, occurrence in food and biological activities of lipids. It also sheds light on different aspects of structured lipids, including SL applications, synthesis (chemical vs. enzymatic), SL and aquaculture and future considerations for SL.展开更多
Recently, the effect of ligand receptor interaction on the membrane structure of liposomes has been studied extensively. However, little is known about how it exists on biological membranes. In this paper, the effect ...Recently, the effect of ligand receptor interaction on the membrane structure of liposomes has been studied extensively. However, little is known about how it exists on biological membranes. In this paper, the effect of Con-canavalin A (ConA) receptor interaction on the structure of cell membranes was studied by Circular Dichroism (CD) and 3lP Nuclear Magnetic Resonance (NMR).CD results of both the purified macrophage membranes and human erythrocyte ghosts (EG) showed that the conformation of membrane proteins changed after ConA bind ing.For further research, 31P-NMR was used to detect the organization of phospholipid molecules on macrophage mem branes. After ConA binding, the tendency to form non bi-layer structure increased with the amount of ConA. The changes of 31P-NMR spectra of living macrophages might be partly due to the above stated reason too.In addition, ConA-receptor interaction also induced similar results of 31P-NMR spectra in EG. In contrast, wheat germ agglutinin (WGA ), another kind of lectin, rarely showed the same influence.展开更多
The cationic amphiphilic lipid type compound 1,1’-{[3,5-bis(dodecyloxycarbonyl)-4-phenyl-1,4- dihydropyridin-2,6-diyl]dimethylene} bispyridinium dibromide (1,4-DHP lipid) (charge +2), is a gene transfection agent. Th...The cationic amphiphilic lipid type compound 1,1’-{[3,5-bis(dodecyloxycarbonyl)-4-phenyl-1,4- dihydropyridin-2,6-diyl]dimethylene} bispyridinium dibromide (1,4-DHP lipid) (charge +2), is a gene transfection agent. The electronic structure of 1,4-DHP lipid molecule was investigated by ab initio quantum mechanics, the charges were derived, and the supramolecular structure formed by 1,4-DHP lipid molecules in water was investigated by means of molecular dynamics simulation, f99 force field, version AMBER 8.0. During the molecular dynamics simulations of 10 ns of MD 1,4-DHP lipid formed a worm-like micellae, which was preserved during the time course of 300 ns of MD simulations. Result was confirmed with the electron microscopy showing extended, rod-like structures as one of the 1,4-DHP lipid supramolecular structures, which are expected to be formed at high 1,4-DHP lipid concentrations.展开更多
The biological pump,driven by phytoplankton production and death,plays a crucial role in the ocean’s sequestration of atmospheric CO_(2).In particular,marginal seas with high primary productivity show a significant c...The biological pump,driven by phytoplankton production and death,plays a crucial role in the ocean’s sequestration of atmospheric CO_(2).In particular,marginal seas with high primary productivity show a significant capacity for carbon fixation.Variations in phytoplankton biomass and community structure are key factors influencing the efficiency of the marine biological pump.The Taiwan Strait(TS)is a unique shallow conduit that connects the East China Sea(ECS)and the South China Sea(SCS),which are subject to seasonal monsoons and episodic events(e.g.,typhoons and floods).Thus,its planktonic ecosystem is significantly influenced by physical processes such as strong ocean currents,coastal upwelling and river discharge,resulting in noticeable seasonal variability.In this study,we examined spatiotemporal patterns of phytoplankton biomass and community structure using phytoplankton-sourced biomarkers from suspended particles in surface waters across all four seasons from 2019 to 2020 in the TS.The findings highlight notable seasonal disparities in phytoplankton biomass,with spring and summer exhibiting significantly higher levels compared to autumn and winter.In order to determine phytoplankton ecosystem responses to various physical and biological processes on a seasonal scale,we used Empirical Orthogonal/Eigen Function(EOF)analysis to investigate the covarying spatiotemporal patterns of:marine-sourced biomarkers and terrestrial-sourced biomarkers in surface suspended particles,a biomass indicator(Chl a),water-mass indicators[sea surface temperature(SST),sea surface salinity(SSS),nutrients],and a hydrodynamic indicator[total suspended solids at surface/bottom water,(TSS_S and TSS_B)].The results identified six physical-biological coupling modes that influence seasonal variations in marine phytoplankton ecosystems within the energetic strait system.Additionally,an in-depth understanding of the coupling between physical process and lipid biomarker signals from suspended particles in the contemporary marine environment can offer valuable insights for interpreting ancient sediment records of phytoplankton ecosystem evolution in the TS.展开更多
Fibroblast growth factor receptors(FGFRs)play an important role in the regulation of cell proliferation,migration and differentiation,while the juxtamembrane domain(JMD)of FGFRs is the key in mediating these transmemb...Fibroblast growth factor receptors(FGFRs)play an important role in the regulation of cell proliferation,migration and differentiation,while the juxtamembrane domain(JMD)of FGFRs is the key in mediating these transmembrane signal transduction processes.Here,we expressed and purified the JMD(398K-470R)of FGFR1 with the presence of transmembrane domain(377I-397Y).The results from nuclear magnetic resonance(NMR)chemical shift analysis demonstrate that the main structure of JMD is disordered.Yet,the N-terminus of JMD was observed to form a short a-helix upon introducing negatively charged lipid 1,2-dioleoyl-sn-glycero-3-phospho-L-serine(DOPS)into its membrane mimic bicelles.Moreover,the N-terminus of JMD interacts with FRS2a,which is a substrate 2a of FGFR.Hence,we propose a model that FGFR1-JMD may interact with FRS2a and negatively charged lipids competitively.Our study provides a new understanding on the role of the JMD of FGFRs.展开更多
The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H2O2 for 60 min at 37 oC have been studied. The followin...The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H2O2 for 60 min at 37 oC have been studied. The following flavonoids;quercetin, rutin and morin significantly protected eryt-hrocytes against lipid peroxidation caused by H2O2. This inhibition of lipid peroxidation could be explained by the presence of at least two hydroxyl groups in ring B of the flavonoid structure, regardless of their positions. However, the flavonoids;quercetin, 3,5,7-trihy- droxy-4'-methoxy flavone-7-rutinoside and 3- hydroxy flavone significantly protected eryt-hrocytes against protein degradation. This inhibition could also be explained by the presence of a hydroxyl group at C-3 in ring C of the flavonoid structure. Quercetin and 3,5,7-trihydroxy-4'- methoxy flvone-7-rutinoside significantly protected erythrocytes against loss of deformability and increased osmotic fragility, indicating that the loss of erythrocyte deformability and the increase in osmotic fragility of erythrocytes exposed to H2O2 are related to protein degradation rather than to lipid peroxidation. The other flavonoids (chrysin, 2-carboxy ethyl dihydroxy flavone, apigenin, cirsimaritin, α-naphto flavone and flavanone) failed to protect erythrocytes against the observed oxidative damages. The results demonstrate the importance of the chemical groups substituted on the basic skeleton of the flavonoids in dictating the type of antioxidant activity, and also demonstrate the hemorheological potentials of flavonoids that have particular protein-antioxidant activities.展开更多
脂质是生物体的重要组成成分,参与细胞膜流动、神经递质传递和运输以及能量供应等多个过程。研究表明,癌细胞为了适应不断变化的生物微环境和快速增殖的需求,其脂质代谢过程不同于正常细胞。因而,对脂质组分进行快速检测、识别及监测研...脂质是生物体的重要组成成分,参与细胞膜流动、神经递质传递和运输以及能量供应等多个过程。研究表明,癌细胞为了适应不断变化的生物微环境和快速增殖的需求,其脂质代谢过程不同于正常细胞。因而,对脂质组分进行快速检测、识别及监测研究,对了解生命过程、监测诊疗过程变化、提升诊疗效率等具有重要意义。质谱是直接获取分子结构最有效的手段之一,在生物分子及脂质鉴定中具有独特优势。近年来,常压质谱技术(ambient mass spectrometry,AMS)不断涌现,该技术无需样品预处理,为直接快速脂质识别及监测提供了有效手段。软电离技术的不断发展也为复杂多样的脂质分子检测提供了广阔的发展空间。电喷雾离子化(ESI)作为主要的软电离技术之一,易于离子化中高极性的生物样品,能够满足生物体内大多数脂质的检测需求。因此,研究人员基于ESI技术,开展了广泛的癌症脂质代谢研究,实现了不同脂质的鉴定和相对定量研究。由于脂质存在丰富的异构体,人们又创新性地将各种化学衍生法和其他技术与AMS结合起来,实现了对复杂脂质结构异构体的准确识别和相对定量研究。基于此,本文综述了近5年用于脂质检测的主要常压质谱技术及应用进展,并汇总了质谱解析脂质精细结构的典型策略。展开更多
Background The nutritional support is one of the important therapeutic strategies for the elderly patients with severe sepsis,but there is controversial in choosing a parenteral nutrition formulation.This study was de...Background The nutritional support is one of the important therapeutic strategies for the elderly patients with severe sepsis,but there is controversial in choosing a parenteral nutrition formulation.This study was designed to compare the therapeutic effects of structured lipid emulsion,physically mixed medium,and long-chain fat emulsion in the treatment of severe sepsis in elderly patients.Methods A total number of 64 elder patients with severe sepsis were enrolled in the study.After a week of enteral nutritional support,the patients were randomly divided into research （structured lipid emulsion as parenteral alimentation） and control groups （physically mixed medium and long-chain fat emulsion as parenteral alimentation）.The alterations of plasma albumin,lipid metabolism,and blood glucose level were recorded after parenteral alimentation and were compared between the two groups.Results The plasma levels of albumin,prealbumin,cholesterol,and triglyceride were decreased in all the patients after one week of enteral nutritional support treatment （t=7.78,P=0.000; t=10.21,P=0.000; t=7.99,P=0.000; and t=10.99,P=0.000）.Further parenteral alimentation with different lipid emulsions had significant effects on the serum prealbumin and albumin （t=3.316,P=0.002; t=3.200,P=0.002）,whilst had no effects on the blood glucose and triglyceride level （t=7.78,P=0.000; t=4.228,P=0.000）.In addition,the two groups had a significantly different Apache Ⅱ score,ventilator time,and hospital stay time （t=-2.213,P=0.031;t=2.317,P=0.024; t=2.514,P=0.015）.Conclusions The structured lipid emulsion was safe as parenteral nutrition for elderly patients with severe sepsis.It was demonstrated to be superior to the physically mixed medium and long-chain fat emulsion with respect to the protein synthesis and prognosis.展开更多
基金financially supported by the National Natural Science Foundation of China(No.22074111)National Key Research and Development Program of China(No.2021YFC2700700)the Opening fund of Hubei Key Laboratory of Bioinorganic Chemistry&Materia Medica(No.BCMM202303)。
文摘As more and more studies have shown that lipid molecules play an important role in the whole biology,in-depth analysis of lipid structure has become particularly important in lipidomics.Mass spectrometry(MS),as the preferred tool for lipid analysis,has greatly promoted the development of this field.However,the existing MS methods still face many difficulties in the in-depth or even comprehensive analysis of lipid structure.In this review,we discuss recent advances in MS methods based on double bond-specific chemistries for the resolving of C=C location and geometry isomers of lipids.This progress has greatly advanced the lipidomics analysis to a deeper structural level and facilitated the development of structural lipid biology.
文摘Various chemical and gas-liquid chromatographic analyses indicate that the lipid A,backbone of the lipopolysaccharide(LPS)isolated from B.fragilis NCTC 9343 is chemically con-stitutεd by a β1,6-interlinked D-glucosamine disaccharide.It is phosphorylated at its 1-positionby a glvcosidic-linkage while the ester-linked phosphate at 4’—position present generally in otherlipid A is depleted.The lipid A is lower fatty acylated in the amount of 5.2 fatty acids/lipid Amolecule(of which 0.73 forms 3-acyloxyacyl groups).The LPS containing such an incompletelipid A component has been shown endowina with a weaker endotoxicitv.
文摘Peculiar properties of morphological structures of organelle membranes were studied by fluorescent confocal microscopy. The list of objects in our experiments was represented by mitochondria, chloroplasts and vacuoles. During this study, identification of lipid microinclusions having the form of such lipid-protein structural microformations as lipid-protein microdomains, vesicles and membrane tubular structures (cytoplasmic transvacuolar strands and nanotubes) located in organelle membranes or bound up with them was conducted. Such membrane probes as laurdan, DPH, ANS and bis-ANS were used. Comparison of fluorescence intensity of these membrane probes was conducted. This investigation of the morphological properties of lipid-protein structural microformations was accompanied with analysis of 1) the phase state and 2) dynamics of microviscosity variations in the membrane elements of isolated plant cell organelles. Distributions of laurdan fluorescence generalized polarization (GP) values for the membrane on the whole and for the intensively fluorescing membrane segments were obtained. It was discovered that the microviscosity of intensively fluorescing membrane segments essentially differed from the microviscosity of the rest part of the membrane. In conclusion, some results of the study of peculiar properties of lipid-protein structural microformations related to the structure of organelle membranes and the discoveries made in this investigation are discussed.
基金supported by the Chinese Scholarship Council(201706790068)the Free Exploration Founded Project of the State Key Laboratory of Food Science and Technology at Jiangnan University(SKLF-ZZA-201705)supported in part by Food Science Research,University of Georgia.
文摘The normal development and maintenance of central neural functions are highly correlated with the amount of docosahexaenoic acid(DHA;ω-3 fatty acid)accumulated in the brain.DHA incorporated at the sn-2 position of lipids is well absorbed by intestinal mucosa and utilized efficiently in vivo.However,modern consumers have a reduced direct intake of DHA and increased intake of saturated fats or ω-6 fatty acid oils,resulting in behavioral and neurophysiological deficits.To provide an understanding of the integrated beneficial effects of DHA on the human brain,this review introduces the positional difference(sn-2 and sn-1,3 positions)of DHA on a glycerol skeleton in natural fats and oils,and further discusses the possible functional mechanism regarding DHA supplementation and the gut-brain axis.The multiple bidirectional routes in this axis offer a novel insight into the interaction between DHA supplementation,the gut microbiota,and brain health.To achieve high sn-2 DHA in diets,it is suggested that sn-2 DHA lipids be enzymatically produced in more efficient and economical ways by improving the specific activities of lipases and optimizing the purification procedures.These types of diets will benefit individuals with strong needs for sn-2 ω-3 lipids such as infants,children,and pregnant and lactating women.
文摘Experiments were conducted to study the effects of selenium (Se) on glutathione peroxidase(GSH-Px) activity and the accumulation of malonaldehyde(MDA),the product of lipid peroxidation in soybean seedling, as well as the effect of Se on cell ultra structure of soybean leaf and nascent root under salt stress. Results showed that appropriate amount of Se addition increased GSH-Px activity in soybean leaves from 0. 810 to 1. 421μmol·g-1 fresh weight·min-1 F = 9.12, and reduced the concentration of MDA from 20.17 to 16.16 μmol·g-1 fresh weight, F = 5.44. Under salt stress,no obvious damage on chloplast membrane was observed in Se treated seedlings,and the structures of chloplast and mitochondrion were integrate,whereas in control (no Se addition),the cell membrane was destroyed seriously,chloplast degraded and mitochondrion disappeared. Compared with control,Se addition increased the dry matter weight of seedling by 2.92% to 21.86%, F =5.97.
文摘Lipids possess a wide range of biological activities in plants, animals and humans. They also serve as important components of our daily diet and provide both energy and essential fatty acids;they also act as carriers of fat-soluble vitamins and help in their absorption. Lipids are crucial as a heating medium for food processing and affect the texture, mouth feel and flavour of foods. Structured lipids (SL) are triacylglycerols (TAG) modified to alter the fatty acid composition and/or their location in the glycerol backbone via chemical or enzymatic means. SL may offer the most efficient means of delivering target fatty acids for nutritive or therapeutic purposes as well as to alleviate specific disease and metabolic conditions. This document discusses chemistry, composition, classification, function, occurrence in food and biological activities of lipids. It also sheds light on different aspects of structured lipids, including SL applications, synthesis (chemical vs. enzymatic), SL and aquaculture and future considerations for SL.
文摘Recently, the effect of ligand receptor interaction on the membrane structure of liposomes has been studied extensively. However, little is known about how it exists on biological membranes. In this paper, the effect of Con-canavalin A (ConA) receptor interaction on the structure of cell membranes was studied by Circular Dichroism (CD) and 3lP Nuclear Magnetic Resonance (NMR).CD results of both the purified macrophage membranes and human erythrocyte ghosts (EG) showed that the conformation of membrane proteins changed after ConA bind ing.For further research, 31P-NMR was used to detect the organization of phospholipid molecules on macrophage mem branes. After ConA binding, the tendency to form non bi-layer structure increased with the amount of ConA. The changes of 31P-NMR spectra of living macrophages might be partly due to the above stated reason too.In addition, ConA-receptor interaction also induced similar results of 31P-NMR spectra in EG. In contrast, wheat germ agglutinin (WGA ), another kind of lectin, rarely showed the same influence.
文摘The cationic amphiphilic lipid type compound 1,1’-{[3,5-bis(dodecyloxycarbonyl)-4-phenyl-1,4- dihydropyridin-2,6-diyl]dimethylene} bispyridinium dibromide (1,4-DHP lipid) (charge +2), is a gene transfection agent. The electronic structure of 1,4-DHP lipid molecule was investigated by ab initio quantum mechanics, the charges were derived, and the supramolecular structure formed by 1,4-DHP lipid molecules in water was investigated by means of molecular dynamics simulation, f99 force field, version AMBER 8.0. During the molecular dynamics simulations of 10 ns of MD 1,4-DHP lipid formed a worm-like micellae, which was preserved during the time course of 300 ns of MD simulations. Result was confirmed with the electron microscopy showing extended, rod-like structures as one of the 1,4-DHP lipid supramolecular structures, which are expected to be formed at high 1,4-DHP lipid concentrations.
基金The National Key Research and Development Program of China under contract No.2019YFE0124700the Scientific Research Foundation of Third Institute of Oceanography,MNR under contract Nos 2019018 and 2019017+2 种基金the National Natural Science Foundation of China under contract Nos 42076038,U22A20585 and 41776099the Guangdong Basic and Applied Basic Research Foundation under contract No.2021A1515011886the STU Scientific Research Start-Up Foundation for Talents under contract No.NTF18011.
文摘The biological pump,driven by phytoplankton production and death,plays a crucial role in the ocean’s sequestration of atmospheric CO_(2).In particular,marginal seas with high primary productivity show a significant capacity for carbon fixation.Variations in phytoplankton biomass and community structure are key factors influencing the efficiency of the marine biological pump.The Taiwan Strait(TS)is a unique shallow conduit that connects the East China Sea(ECS)and the South China Sea(SCS),which are subject to seasonal monsoons and episodic events(e.g.,typhoons and floods).Thus,its planktonic ecosystem is significantly influenced by physical processes such as strong ocean currents,coastal upwelling and river discharge,resulting in noticeable seasonal variability.In this study,we examined spatiotemporal patterns of phytoplankton biomass and community structure using phytoplankton-sourced biomarkers from suspended particles in surface waters across all four seasons from 2019 to 2020 in the TS.The findings highlight notable seasonal disparities in phytoplankton biomass,with spring and summer exhibiting significantly higher levels compared to autumn and winter.In order to determine phytoplankton ecosystem responses to various physical and biological processes on a seasonal scale,we used Empirical Orthogonal/Eigen Function(EOF)analysis to investigate the covarying spatiotemporal patterns of:marine-sourced biomarkers and terrestrial-sourced biomarkers in surface suspended particles,a biomass indicator(Chl a),water-mass indicators[sea surface temperature(SST),sea surface salinity(SSS),nutrients],and a hydrodynamic indicator[total suspended solids at surface/bottom water,(TSS_S and TSS_B)].The results identified six physical-biological coupling modes that influence seasonal variations in marine phytoplankton ecosystems within the energetic strait system.Additionally,an in-depth understanding of the coupling between physical process and lipid biomarker signals from suspended particles in the contemporary marine environment can offer valuable insights for interpreting ancient sediment records of phytoplankton ecosystem evolution in the TS.
基金Special Foundation of President of the Chinese Academy of Sciences(Grant No.,YZJJ2021QN33,YZJJ2020QN27)Collaborative Innovation Program of Hefei Science Center,CAS(2020HSC-CIP008).
文摘Fibroblast growth factor receptors(FGFRs)play an important role in the regulation of cell proliferation,migration and differentiation,while the juxtamembrane domain(JMD)of FGFRs is the key in mediating these transmembrane signal transduction processes.Here,we expressed and purified the JMD(398K-470R)of FGFR1 with the presence of transmembrane domain(377I-397Y).The results from nuclear magnetic resonance(NMR)chemical shift analysis demonstrate that the main structure of JMD is disordered.Yet,the N-terminus of JMD was observed to form a short a-helix upon introducing negatively charged lipid 1,2-dioleoyl-sn-glycero-3-phospho-L-serine(DOPS)into its membrane mimic bicelles.Moreover,the N-terminus of JMD interacts with FRS2a,which is a substrate 2a of FGFR.Hence,we propose a model that FGFR1-JMD may interact with FRS2a and negatively charged lipids competitively.Our study provides a new understanding on the role of the JMD of FGFRs.
文摘The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H2O2 for 60 min at 37 oC have been studied. The following flavonoids;quercetin, rutin and morin significantly protected eryt-hrocytes against lipid peroxidation caused by H2O2. This inhibition of lipid peroxidation could be explained by the presence of at least two hydroxyl groups in ring B of the flavonoid structure, regardless of their positions. However, the flavonoids;quercetin, 3,5,7-trihy- droxy-4'-methoxy flavone-7-rutinoside and 3- hydroxy flavone significantly protected eryt-hrocytes against protein degradation. This inhibition could also be explained by the presence of a hydroxyl group at C-3 in ring C of the flavonoid structure. Quercetin and 3,5,7-trihydroxy-4'- methoxy flvone-7-rutinoside significantly protected erythrocytes against loss of deformability and increased osmotic fragility, indicating that the loss of erythrocyte deformability and the increase in osmotic fragility of erythrocytes exposed to H2O2 are related to protein degradation rather than to lipid peroxidation. The other flavonoids (chrysin, 2-carboxy ethyl dihydroxy flavone, apigenin, cirsimaritin, α-naphto flavone and flavanone) failed to protect erythrocytes against the observed oxidative damages. The results demonstrate the importance of the chemical groups substituted on the basic skeleton of the flavonoids in dictating the type of antioxidant activity, and also demonstrate the hemorheological potentials of flavonoids that have particular protein-antioxidant activities.
文摘脂质是生物体的重要组成成分,参与细胞膜流动、神经递质传递和运输以及能量供应等多个过程。研究表明,癌细胞为了适应不断变化的生物微环境和快速增殖的需求,其脂质代谢过程不同于正常细胞。因而,对脂质组分进行快速检测、识别及监测研究,对了解生命过程、监测诊疗过程变化、提升诊疗效率等具有重要意义。质谱是直接获取分子结构最有效的手段之一,在生物分子及脂质鉴定中具有独特优势。近年来,常压质谱技术(ambient mass spectrometry,AMS)不断涌现,该技术无需样品预处理,为直接快速脂质识别及监测提供了有效手段。软电离技术的不断发展也为复杂多样的脂质分子检测提供了广阔的发展空间。电喷雾离子化(ESI)作为主要的软电离技术之一,易于离子化中高极性的生物样品,能够满足生物体内大多数脂质的检测需求。因此,研究人员基于ESI技术,开展了广泛的癌症脂质代谢研究,实现了不同脂质的鉴定和相对定量研究。由于脂质存在丰富的异构体,人们又创新性地将各种化学衍生法和其他技术与AMS结合起来,实现了对复杂脂质结构异构体的准确识别和相对定量研究。基于此,本文综述了近5年用于脂质检测的主要常压质谱技术及应用进展,并汇总了质谱解析脂质精细结构的典型策略。
文摘Background The nutritional support is one of the important therapeutic strategies for the elderly patients with severe sepsis,but there is controversial in choosing a parenteral nutrition formulation.This study was designed to compare the therapeutic effects of structured lipid emulsion,physically mixed medium,and long-chain fat emulsion in the treatment of severe sepsis in elderly patients.Methods A total number of 64 elder patients with severe sepsis were enrolled in the study.After a week of enteral nutritional support,the patients were randomly divided into research （structured lipid emulsion as parenteral alimentation） and control groups （physically mixed medium and long-chain fat emulsion as parenteral alimentation）.The alterations of plasma albumin,lipid metabolism,and blood glucose level were recorded after parenteral alimentation and were compared between the two groups.Results The plasma levels of albumin,prealbumin,cholesterol,and triglyceride were decreased in all the patients after one week of enteral nutritional support treatment （t=7.78,P=0.000; t=10.21,P=0.000; t=7.99,P=0.000; and t=10.99,P=0.000）.Further parenteral alimentation with different lipid emulsions had significant effects on the serum prealbumin and albumin （t=3.316,P=0.002; t=3.200,P=0.002）,whilst had no effects on the blood glucose and triglyceride level （t=7.78,P=0.000; t=4.228,P=0.000）.In addition,the two groups had a significantly different Apache Ⅱ score,ventilator time,and hospital stay time （t=-2.213,P=0.031;t=2.317,P=0.024; t=2.514,P=0.015）.Conclusions The structured lipid emulsion was safe as parenteral nutrition for elderly patients with severe sepsis.It was demonstrated to be superior to the physically mixed medium and long-chain fat emulsion with respect to the protein synthesis and prognosis.
