SUPEROXIDE DISMUTASE ACTIVITY AND MEMBRANE LIPIDS COMPOSITION OF ERYTHROCYTES IN PATIENTS WITH DILATEDCARDIOMYOPATHY

Objective To rurther conflrm the role or lipld-peroxldation caused by oxygen free radicals injury played in the pathogenesis of dllsted cardlomypathy. MethOds The superoxide dismutase activities and lipids composltion of erythrocytes in 18 patients with dilated cardiomyopathy and 16 healthy controls were measured. Results Superoxide dlsmutase(SOD) activites of erythrocytes were lower in dilated cardiomyopathy(DCM) patients than that in healthy controls (P <o. oo1 ). The lipids composition of erythrocytes has changed in the DCM patients compared with healthy controls: total liplds changed little (P >o. o5); total phospholipids were lower, but not significantly (P>o. o5): total cholesterol increased significantly (P <o. o5). The cholesterol to phospholipids molecular ratio of erythrocyte membrane has increased remarkably (P >o. o5). Conclusion It can be supposed that decreased SOD activitles play an important role in the damage or membrane system and the pathogensis of DCM.

On COVID-19 and Membrane Lipids and Public Health

Coronavirus has a lipid membrane.Whist replication requires hijacking the RNA tools of the host to synthesize virion protein,that then has to be wrapped in a lipid membrane to enable the budding off which extends the infection.Recent studies implicate certain essential fatty acids with replication suppression properties.The lipid membrane is commonly thought of as a fatty barrier to water solubles.It is however highly ordered and compositionally specific to cellular and sub cellular functions.There will likely also be an optimum specificity for the viral coat.Whist DNA,RNA and protein compositions are not affected by diet,the lipid membrane is.Moreover,the greater sensitivity of males over females to inadequacy of these essential fatty acids and membrane integrity has been known since the 1960 s.With evidence that arachidonic and docosahexaenoic acids exhibiting anti-viral,immune,anti-inflammatory,blood pressure control and resolvin activity,their status needs to be urgently examined in relation to the prevention and therapy for Covid-19.It would also be advisable to re-assess food policy.The lipid requirements for the membrane rich systems as in the brain,nervous,vascular and immune systems have not been considered.There is little doubt these were significant in shaping the human genome over several million years.Departure from such conditions would be predicted to put populations at risk to disorder and infection,with males being more at risk than females.

Changes in Unsaturated Levels of Fatty Acids in Thylakoid PSII Membrane Lipids During Chilling-induced Resistance in Rice

Temperature is one of the abiotic factors limiting growth and productivity of plants. In the present work, the effect of low non-freezing temperature, as an inducer of ＂chilling resistance＂, was studied in three cultivars of rice （Oryza sativa L.）, japonica cv. 9516 （j-9516）, the two parental lines of superhigh-yield hybrid rice between subspecies, Peiai/E32 （ji-PE）, and the traditional indica hybrid rice Shanyou 63 （i-SY63）. Leaves of chill-treated rice showed chilling-induced resistance, as an increase of their low-temperature tolerance was measured using chlorophyll fluorescence measurements, revealing a change in photosystem II （PSII） efficiency. After 5 d of exposure to 11 ~C under low light （100 pmol·m^-2·s^-1）, levels of unsaturated fatty acids in PSII thylakoid membrane lipids decreased during the initial 1-2 d, then increased slowly and reached 99.2%, 95.3% and 90.1% of the initial value （0 d） in j-9516, ji-PE and i-SY63, respectively, on the fifth day. However, under medium light （600 μmol·m^-2·s^-1）, all cultivars experienced similar substantial photoinhibition, which approached steady state levels after a decline in levels of unsaturated fatty acids in PSII thylakoid membrane lipids to about 57.1%, 53.8% and 44.5% of the initial values （0 d） in j-9516, ji-PE and i-SY63 on the fifth day. Under either chilling-induced resistance （the former） or low temperature photoinhibition （the latter） conditions, the changes of other physiological parameters such as D1 protein contents, electron transport activities of PSII （ETA）, Fv/Fm, xanthophyl cycle activities expressed by DES （deepoxide state） were consistent with that of levels of unsaturated fatty acids in PSII thylakoid membrane lipids. So there were negative correlations between saturated levels of fatty acids （16：1（3t）, 16：0, 18：0）, especially the 16：1（3t） fatty acid on thylakoid membrane and other physiological parameters, such as D1 protein contents, ETA and （A＋Z）/（A＋V＋Z）. A specific role of desaturation of fatty acids and the photoprotective pigments of the xanthophyl cycle, leading to an acclimation response in thylakoid membrane lipids may be involved. We conclude that chilling-induced resistance is accelerated by the unsaturation of thylakoid membranes, and the ability of rice plants to cold-harden can be enhanced by genetic engineering.

Influences of 1-methylcyclopropene-containing papers on the metabolisms of membrane lipids in Anxi persimmons during storage

Objectives:The aim of this work was to analyse the effects of 1-methylcyclopropene(1-MCP)treatment on the metabolisms of membrane lipids in postharvest Anxi persimmons during storage.Materials and methods:Anxi persimmon(Diospyros kaki L.f.cv.Anxi)fruits were treated by paper containing 1-MCP with a concentration of 1.35μl/l.The cellular membrane permeability was analysed by the electric conductivity meter.The activities of lipoxygenase(LOX),phospholipase(PLD)and lipase were determined by spectrophotometry.The component and relative amounts of membrane fatty acids were determined using gas chromatograph(GC).Results:The 1-MCP-treated Anxi persimmons manifested a lower electrolyte leakage rate,lower LOX,PLD and lipase activities,higher levels of unsaturated fatty acids(USFAs),higher ratio of USFAs to saturated fatty acids(SFAs)(U/S),higher index of USFAs(IUFA),but lower levels of SFAs.Conclusions:The degradation and the metabolisms of membrane lipids could be suppressed by 1-MCP treatment,which might be accountable for the delaying softening of postharvest Anxi persimmons during storage.

Effects of dehydration speed on the metabolism of membrane lipids and its relation to the browning of the Thompson seedless grape

Xinjiang is the main producing area of raisins and the largest green raisins production base in China.The browning of Thompson seedless grape raisin is extremely serious during the drying process,and has become the key issue in the development of Xinjiang raisin industry.Previous studies have shown that dehydration speed has a great impact on the browning of Thompson seedless grape,but few relevant mechanisms have been studied.Here,we demonstrate the effect of dehydration speed on lipid metabolism and its relation to the browning of the Thompson seedless grape during drying.Compared to slow dehydration treatment,rapid dehydration treatment of the Thompson seedless grape exhibited a lower degree of browning and activities of lipoxygenase(LOX),a higher index of unsaturated fatty acids and degree of unsaturated fatty acid.Moreover,the Thompson seedless grape treated with rapid dehydration resulted in a lower rate of superoxide anion production,hydrogen peroxide content,membrane permeability,and malondialdehyde content.These findings demonstrate that rapid dehydration inhibiting the browning of Thompson seedless grapes might be due to the inhibiting activities of LOX and the lower accumulation of reactive oxygen species.These activities can inhibit lipid peroxidation and slow the decomposition of unsaturated fatty acid in the membrane in Thompson seedless grapes,protecting the cellular membrane structural integrity,which may result in less contact of polyphenol oxidase with phenolic substrates and less enzymatic browning during drying.The results provide a theoretical basis for the application of rapid dehydration in drying Thompson seedless grapes.

Effects of salinity on activities of H^+-ATPase, H^+-PPase and membrane lipid composition in plasma membrane and tonoplast vesicles isolated from soybean(Glycine max L.) seedlings

The effects of NaCl stress on the H +-ATPase, H +-PPase activity and lipid composition of plasma membrane(PM) and tonoplast(TP) vesicles isolated from roots and leaves of two soybean cultivars(Glycine max L.) differing in salt tolerance(Wenfeng7, salt-tolerant; Union, salt-sensitive) were investigated. When Wenfeng7 was treated with 0.3%(W/V) NaCl for 3 d, the H +-ATPase activities in PM and TP from roots and leaves exhibited a reduction and an enhancement, respectively. The H +-PPase activity in TP from roots also increased. Similar effects were not observed in roots of Union. In addition, the increases of phospholipid content and ratios of phospholipid to galactolipid in PM and TP from roots and leaves of Wenfeng7 may also change membrane permeability and hence affect salt tolerance.

Effects of Vitamin E on the Activities of Protective Enzymes and Membrane Lipid Peroxidation in Leymus Chinensis under Drought Stress

Leymus chinensis seedlings were treated with 0.05--10 mmol/L vitamin E under osmotic stress in the presence of polyethylene glycol（PEG） as the stress reagent. The effects of the different concentrations of exogenous vitamin E on the activities of SOD, POD and free proline, and the MDA contents under drought stress were examined so as to ascertain the mechanism of Leymus chinensis resistance to drought stress and explore the possible preventive measures. The results indicate that the activities of SOD and POD decreased but the free proline and MDA contents increased as drought stress was accentuated, showing an enhancement of oxidative stress that may cause a decline in membrane stabilization. However, the activities of SOD and POD and the free proline content increased, whereas the MDA content reduced in Leymus chinensis pretreated with vitamin E in comparison with that of the control. This indicates that exogenous vitamin E enhanced the antioxidation of Leymus chinensis seedlings. It suggests that cytomembrane can be protected from damage by increasing the free proline content and the activities of SOD and POD that result in enhancing the drought resistance of Leymus chinensis seedlings.

Mechanical responses of the bio-nano interface: A molecular dynamics study of graphene-coated lipid membrane

Bio-nano interfaces between biological materials and functional nanodevices are of vital importance in relevant energy and information exchange processes, which thus demand an in-depth understanding. One of the critical issues from the application viewpoint is the stability of the bio-nano hybrid under mechanical perturbations. In this work we explore mechanical responses of the interface between lipid bilayer and graphene under hydrostatic coating provides remarkable resistance to the pressure or indentation loads, We find that graphene loads, and the intercalated water layer offers additional protection. These findings are discussed based on molecular dynamics simulation results that elucidate the molecular level mechanisms, which provide a basis for the rational design of bionanotechnology- enabled aoolications such as biomedical devices and nanotheraoeutics.

Membrane Lipid Replacement: Clinical Studies Using a Natural Medicine Approach to Restoring Membrane Function and Improving Health

Functional oral supplements containing cell membrane glycerolphospholipids and antioxidants have been used to safely replace damaged membrane lipids that accumulate during aging and in various clinical conditions. This approach differs from other dietary and intravenous interventions in the composition of phospholipids and the presence of fructooligosaccharides that protect the phospholipids against oxidation and bile and enzymatic damage. Various chronic clinical conditions are characterized by membrane phospholipid oxidative damage, resulting in loss of cellular function. Recent clinical trials have shown the benefits of Membrane Lipid Replacement in replenishing damaged membrane lipids and restoring mitochondrial function, resulting in reductions in fatigue in aged subjects and patients with a variety of clinical diagnoses. Recent in vitro experiments with nonphysiological concentrations of phospholipids did not result in enhancement of mitochondrial electron transport enzyme activities. This can be explained by the use of the wrong phospholipid fatty acids, over-dilution of membrane constituents and mitochondrial swelling. A similar phenomenon was seen when human sperm were incubated in vitro with high concentrations of glycerolphospholipids and their motility was assessed. Only lower, more physiological concentrations of glycerolphospholipids stimulated sperm motility. Additional studies are needed to determine the functional effects of Membrane Lipid Replacement on other cellular membranes, such as the plasma membrane and other intracellular membranes of various cells and tissues.

Dynamic and adaptive membrane lipid remodeling in leaves of sorghum under salt stress

Salt stress limits plant growth and development.In this study,changes in membrane lipids were investigated in leaves of sorghum seedlings subjected to salt stress(150 mmol L^(-1)NaCl).Galactolipids(DGDG and MGDG)accounted for more than 65%of the total glycerolipids in sorghum leaves.The predominance of C36 molecular species in MGDG suggested that sorghum is an 18:3 plant.Under Na Cl treatment,the content of major phospholipids(PC and PE)increased,accompanied by the activation of their metabolism pathways at the transcriptional level.In contrast,the proportion of MGDG and PG dropped drastically,leading to a decreased ratio of plastidic to non-plastidic lipids.An adjustment of glycerolipid pathway between the cytosolic and plastidic compartments was triggered by salt stress,as reflected by the increased conversion of PC to PA,providing precursors for galactolipid synthesis.The elevated DGDG resulted in increased DGDG/MGDG and bilayer/non-bilayer lipid ratios.The double-bond index of PC,PE,and DGDG increased markedly,evidently owing to the increased expression of FAD3 and FAD8.These findings will be helpful for understanding dynamic membrane lipid changes and adaptive lipid remodeling in sorghum response to salt stress.

Effects of Low-Phosphorus Stress on Membrane Lipid Peroxidation and Protective Enzyme Activities in Leaves of Different Rice (Oryza sativa)Cultivars

Membrane lipid peroxidation and protective enzyme activity in leaves of low-phosphorus-tolerant rice cultivars Dalidao and Liantangzao 3, and low-phosphorus-sensitive cultivars Huzhanqi and Xinsanbaili were studied under low phosphorus stress with sandy culture. Results indicated that low-phosphorus stress aggravated the membrane lipid peroxidation in rice leaves, and it was more severe in low-phosphorus-sensitive cultivars than that in low-phosphorus-tolerant eultivars. During the period of low-phosphorus stress, the activities of SOD, CAT and POD maintained relatively stable in low-phosphorustolerant cultivars, whereas those increased obviously at early stage and subsequently decreased rapidly in the low-phosphorus-sensitive cultivars, suggesting that the absolute activities of protective enzymes had no relation with the low-phosphorus stress, while the changing trend was reverse.

Effects of Wounding and Exogenous Jasmonic Acid on the Peroxidation of Membrane Lipid in Pea Seedlings Leaves

The changes of malondialdehyde （MDA）, H2O2, and O2^7 content, or the activities of superoxide dismutase （SOD）, catalase （CAT）, ascrobate peroxidase （APX）, peroxidase （POD）, phenylalanine ammonia lyase （PAL）, and polyphenol oxidase （PPO） in pea seedlings （Pisum sativum L.） under wounding and treatment of exogenous jasmonic acid （JA） were investigated. The results showed that the activities of both phenylalanine ammonia lyase （PAL） and polyphenol oxidase （PPO） were significantly increased by wounding and application of JA. The metabolism of reaction oxidative species （ROS） was enhanced, especially O2^7 and H2O2 appeared to rapidly increase. The activities of antioxidant enzymes such as SOD, CAT, APX and POD were also increased. Treatment of JA of 1 or 10 μmol L^-1 could effectively induce plant defense response, and thus decrease the peroxidation of cell membrane lipid. However, high concentration of JA （100 μmol L^-1） resulted in unbalance of metabolism of ROS and promoted the peroxidation of cell membrane lipid. We thus suggested that JA, under the suitable concentration, could induce defense response of pea seedlings to wounding.

DYNAMIC PARAMETER OF MEMBRANE LIPID IN LUNG CANCER CELL LINES, CARCINOGENESIS CELLS AND CANCER CELLS ISOLATED FROM PATIENTS WITH LUNG CANCER

With the aid of the Fluorescent lipophilic probe DPH (1, 6- diphenyl- 1, 3, 5- hexatriene ), the degree of microviscosity (η) and lipid fluidity (LFU) obtained from lung cancer lines and carcinogenesis cells induced by irradiation as well as the patients with lung cancer were quantitatively monitored by Fluorescence polarization. The results have shown a marked decreased in η and a significant increase in LFU in various tumor cells as compared to normal cells. Sometime, the degree of fluidity in carcinogenesis cells Induced by radiation and the patients with lung cancer have shown to be similar pattern. The possibility that these dynamic parameter may serve as a diagnostic tool for an early detection of lung cancer is discussed.

First integrals of the axisymmetric shape equation of lipid membranes

The shape equation of lipid membranes is a fourth-order partial differential equation. Under the axisymmetric condi- tion, this equation was transformed into a second-order ordinary differential equation （ODE） by Zheng and Liu （Phys. Rev. E 48 2856 （1993））. Here we try to further reduce this second-order ODE to a first-order ODE. First, we invert the usual process of variational calculus, that is, we construct a Lagrangian for which the ODE is the corresponding Euler-Lagrange equation. Then, we seek symmetries of this Lagrangian according to the Noether theorem. Under a certain restriction on Lie groups of the shape equation, we find that the first integral only exists when the shape equation is identical to the Will- more equation, in which case the symmetry leading to the first integral is scale invariance. We also obtain the mechanical interpretation of the first integral by using the membrane stress tensor.

Study of Oligonucleotide Fixation on Bilayer Lipid Membranes by Patch-clamp Pipette Support

One kind of novel BLMs was fabricated by patch-clamp pipette technology characterized in considerably sensitive to changes of electrochemical parameters.Detectiye currents and voltage presented linear relationship when BLMs was formed and it could be confirmed by Gramicidin method.Ion current was increased by dihexyl (C_ (12)) modified ssDNA fixed on the BLMs and also indicated linear relationship to ssDNA's concentration due to the interaction of (C_ 12)-ssDNA and BLMs.Further more,the regression equations were different from BLMs fixed with ssDNA probe and a blank control BLM in the same experimental conditions.The ssDNA probe was successfully fixed on patch-clamp pipette supported-BLMs.Based on our studies,a biosensor with reactive element of patch-clamp pipette-supported BLMs has been established.

Study of Sweet-Sensitive Taste Sensor with Lipid/Polymer Membranes

A sweet-sensitive taste sensor was investigated with potetiometric measurement.The transducer was a lipid/polymer membrane composed of tetradodecylammonium bromide,di-n-octylphenylphosphonate and polyvinyl chloride,which surface was modified with polyphenol and the solvent 30% EtOH,100 mmol/L KC1 and 10 mmol/L KOH.Balancing hydrophobic/ hydrophilic property and charge density on the membrane surface was susceptible to sensitivity for sweetener.Interaction between the membrane and sweet taste substances such as sucrose was detected as membrane potential change.

Study on Biologic Activity for Membrane of Normal Bone Marrow Cells with Infection of Epidemic Hemorrhagic Fever Virus

Using DPH fluorescence probe, the membrane of normal bone marrow cells with infection of epidemic hemorrhagic fever virus (EHFV) was labeled. The membrane lipid fluidity was obviously decreased from the membrane lipid fluorescence polarization. The membrane lipid fluidity of lympho- cyte, monocyte and neutrophilic granulocyte was dynamically observed. After culturing the cells for 1, 6, 24 and 72 h, it was found that all the membrane lipid fluidity of the infected cells was de- creased obviously with the longer the culturing time, the more obvious it. Compared with the normal control groups, there was a significant difference statistically (P<0. 05-0. 01). It was suggested that the decrease of the membrane lipid fluidity of normal bone marrow cell with infection of EHFV had correlation with the degree of virus invading and cellfunction injury.

Challenges in the theoretical investigations of lipid membrane configurations

We report some key results in the theoretical investigations of configurations of lipid membranes and present several challenges in this field,which involve（i）the exact solutions to the shape equation of lipid vesicles,（ii）the exact solutions to the governing equations of open lipid membranes,（iii）the neck condition of two-phase vesicles in the budding state,（iv） the nonlocal theory of membrane elasticity,and（v）the relationship between the symmetry and the magnitude of the free energy.

Conductance and Capacity of Plain Lipid Membranes under Conditions of Variable Gravity

Biological cell membranes are complex structures containing mainly lipids and proteins. Functional aspects of such membranes are usually attributed to membrane integral proteins. However, it is well established that parameters of the lipid matrix are modifying the function of proteins. Additionally, electrical capacity and conductance of the plain lipid matrix of membranes are contributing directly to cellular functions as there is, for example, the propagation of action potentials. Accordingly the dependence of these parameters on changes of gravity might be important in the field of life sciences under space conditions. In this study consequently we have performed experiments in parabolic flight campaigns utilizing the patch-clamp technology to investigate conductance and capacity of plain lipid vesicle membranes under conditions of changing gravity. Both capacity and conductance were found to be gravity dependent. The changes in capacity could be contributed to changes in membrane geometry. Significant permeability in plain lipid membranes could be only observed at high potentials, where spontaneous current fluctuations occurred. The probability of these fluctuations was gravity dependent.

Protective Roles of Brassinolide on Rice Seedlings under High Temperature Stress

Two indica rice （Oryza sativa L.） materials, Xieqingzao B （sensitive to heat stress） and 082 （tolerant to heat stress） were used to study the role of brassinolide （BR） in protection of rice seedlings from heat stress. Young seedlings were subjected to high temperature （38℃/30℃） and sprayed with 0.005 mg/L of BR. Analysis was conducted on the contents of chlorophyll, protein and malondialdehyde （MDA）, the leakage of electrolyte, the activities of peroxidase （POD） and superoxide dismutase （SOD） and their isozymes expression levels in leaves. Under the high temperature treatment, application of BR significantly increased the contents of chlorophyll and protein, and the activities of POD and SOD, and reduced the content of MDA and the leakage of electrolyte in the leaves of the heat-sensitive material Xieqingzao B, whereas BR had less effect on those of the heat-tolerant material 082 relatively. The BR treatment enhanced the expression of POD isozymes in the leaves of both materials. Under the high temperature stress and BR treatment, the expression of four SOD isozymes reduced in 082, but the expression of two SOD isozymes increased in Xieqingzao B. This suggests that BR plays an important role in protection of rice seedlings from heat stress by enhancing the activities or expression level of protective enzymes in the leaves. The materials with various heat-tolerance might differ in the mechanism of response to heat stress with BR application.