Background:Diterpenoid esters are considered to be the main toxic components and bioactive constituents of Euphorbia lathyris L.(EL).Euphorbia factors L1(EF1),L2(EF2),and L3(EF3),the main diterpenoid esters of EL,have...Background:Diterpenoid esters are considered to be the main toxic components and bioactive constituents of Euphorbia lathyris L.(EL).Euphorbia factors L1(EF1),L2(EF2),and L3(EF3),the main diterpenoid esters of EL,have been found to cause intestinal diarrhea and induce intestinal inflammation in mice.This research aimed to explore the effects of major diterpenoid esters from EL on intestinal inflammation,as well as to clarify their possible targets and molecular mechanisms in vivo and vitro.Methods:Caco-2 cells and BALB/c mice were intervened with EFL1,EFL2,and EFL3,respectively.The expressions of TLR4,NLRP3,NF-κB p65,LXRα,ABCA1,TNF-αand IL-1βwere measured by Real-time PCR and ELISA.Cholesterol efflux levels were examined using cholesterol efflux kit.Flow cytometry was applied to detect lipid rafts abundance.Confocal microscopy was applied to investigate co-localization of lipid rafts and TLR4.Results:Our results revealed that EFL1,EFL2,and EFL3 inhibited LXRα,ABCA1 expression,and cholesterol efflux,promoted colocalization of TLR4 and lipid rafts,and up-regulated TLR4,NLRP3,NF-κB p65,TNF-αand IL-1βexpressions.Conclusion:These findings reveal that the mechanisms by which EFL1,EFL2,and EFL3 induce intestinal inflammation may be associated with LXRα/ABCA1-regulated lipid rafts and TLR4-mediated pathways.展开更多
Caveolae and non-caveolar lipid rafts are two types of membrane lipid microdomains that play important roles in insulin-stimulated glucose uptake in adipocytes. In order to ascertain their specific functions in this p...Caveolae and non-caveolar lipid rafts are two types of membrane lipid microdomains that play important roles in insulin-stimulated glucose uptake in adipocytes. In order to ascertain their specific functions in this process, caveolae were ablated by caveolin-1 RNA interference. In Cav-1 RNAi adipocytes, neither insulin-stimulated glucose uptake nor Glut-4 （glucose transporter 4） translocation to membrane lipid microdomains was affected by the ablation of caveolae. With a modified sucrose density gradient, caveolae and non-caveolar lipid rafts could be separated. In the wild-type 3T3- L l adipocytes, Glut-4 was found to be translocated into both caveolae and non-caveolar lipid rafts. However, in Cav1 RNAi adipocytes, Glut-4 was localized predominantly in non-caveolar lipid rafts. After the removal of insulin, caveolaelocalized Glut-4 was internalized faster than non-caveolar lipid raft-associated Glut-4. The internalization of Glut-4 from plasma membrane was significantly decreased in Cav-1 RNAi adipocytes. These results suggest that insulin-stimulated Glut-4 translocation and glucose uptake are caveolae-independent events. Caveolae play a role in the internalization of Glut-4 from plasma membrane after the removal of insulin.展开更多
Amyloid-beta peptide is the main component of amyloid plaques, which are found in Alzhei- mer＇s disease. The generation and deposition of amyloid-beta is one of the crucial factors for the onset and progression of Al...Amyloid-beta peptide is the main component of amyloid plaques, which are found in Alzhei- mer＇s disease. The generation and deposition of amyloid-beta is one of the crucial factors for the onset and progression of Alzheimer＇s disease. Lipid rafts are glycolipid-rich liquid domains of the plasma membrane, where certain types of protein tend to aggregate and intercalate. Lipid rafts are involved in the generation of amyloid-beta oligomers and the formation of amyloid-beta peptides. In this paper, we review the mechanism by which lipid rafts disturb the aberrant deg- radative autophagic-lysosomal pathway of amyloid-beta, which plays an important role in the pathological process of Alzheimer＇s disease. Moreover, we describe this mechanism from the view of the Two-system Theory of fasciology and thus, suggest that lipid rafts may be a new target of Alzheimer＇s disease treatment.展开更多
Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007.The primary source of the Yellow Sea green tides is the attached algae on the Pyropia...Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007.The primary source of the Yellow Sea green tides is the attached algae on the Pyropia aquaculture rafts in the Subei Shoal.Ulva prolifera and Blidingia(Italic)sp.are the main species observed on Pyropia aquaculture rafts in the Subei Shoal.We found that U.prolifera has strong buoyancy and a rapid growth rate,which may explain why it is the dominant species of green tides that occur in the China's sea area of the Yellow Sea.The growth rate of floating U.prolifera was about 20%–31%d–1,which was much higher than Blidingia(Italic)sp.There were about 1.7×104 t of attached algae on the Pyropia aquaculture rafts in May 2012.We found that 39%of attached algae could float when the tide rose in the Subei Shoal,and U.prolifera accounted for 63%of the floating algae.Our analysis estimated that about 4000 t of attached U.prolifera floated into the surrounding waters of the Subei Shoal during the recycling period of aquaculture rafts.These results suggest that the initial floating biomass of large-scale green tides in the Yellow Sea is determined by the U.prolifera biomass attached to Pyropia aquaculture rafts,further impacting the scale of the green tide。展开更多
Apatinib,an oral anti-angiogenic agent,has been shown to have anti-cancer effects for several cancer cell types.However,little is known about the direct anti-tumor activity of apatinib for breast cancer cells.Herein,t...Apatinib,an oral anti-angiogenic agent,has been shown to have anti-cancer effects for several cancer cell types.However,little is known about the direct anti-tumor activity of apatinib for breast cancer cells.Herein,the direct effect of apatinib on breast cancer cells and its mechanism of action were assessed.Cell viability was measured with a Cell Counting Kit-8.Cell apoptosis was assessed by flow cytometry.The expression of caspase-8 and the cleavage of poly ADP ribose polymerase were assessed by Western blotting analysis.Lipid rafts and Fas distribution were determined by immunofluorescence microscopy.Apatinib suppressed breast cancer cell proliferation in a dose-dependent manner.Furthermore,apatinib enhanced the aggregation of lipid rafts and the redistribution of Fas into lipid rafts.Pretreatment with methyl-β-cyclodextrin,a cholesterol-sequestering agent,significantly reversed Fas redistribution and apatinib-induced apoptosis.In conclusion,these results demonstrated that apatinib induced apoptosis of breast cancer cells partially through recruitment of Fas into lipid rafts.展开更多
GP64 is the major envelope glycoprotein associated with the budded virus (BV) of Autographa californica nucleopolyhedrovirus (AcMNPV) and is essential for attachment and budding of BV particles. Confocal microscopy an...GP64 is the major envelope glycoprotein associated with the budded virus (BV) of Autographa californica nucleopolyhedrovirus (AcMNPV) and is essential for attachment and budding of BV particles. Confocal microscopy and flotation assays established the presence of lipid raft domains within the plasma membranes of AcMNPV-infected Sf9 cells and suggested the association of GP64 with lipid rafts during infection. GP64 and filamentous actin (F-actin) were found to co-localise at the cell cortex at 24 and 48 hpi and an additional restructuring of F-actin during infection was visualised, resulting in a strongly polarised distribution of both F-actin and GP64 at the cell cortex. Depletion of F-actin, achieved by treatment of Sf9 cells with latrunculin B (LB), resulted in the redistribution of GP64 with significant cytoplasmic aggregation and reduced presence at the plasma membrane. Treatment with LB also resulted in reduced production of BV in Sf9 cells. Analysis of virus gene transcription confirmed this reduction was not due to decreased trafficking of nucleocapsids to the nucleus or to decreased production of infectious progeny nucleocapsids. Reduced BV production due to a lack of GP64 at the plasma membrane of AcMNPV-infected Sf9 cells treated with LB, suggests a key role for F-actin in the egress of BV.展开更多
Lipid rafts are sterol and sphingolipid rich membrane domains that possibly may play roles in multiple cellular processes. These domains are still the matter of debate and it is still unknown by which mechanism if any...Lipid rafts are sterol and sphingolipid rich membrane domains that possibly may play roles in multiple cellular processes. These domains are still the matter of debate and it is still unknown by which mechanism if any and organisms promote their formation. This study centers on the ease of in vitro formation of lipid rafts-like structures as it relates to the relative availability of sphingolipids, phospholipids, cholesterol, and membrane proteins. Following a 12 h incubation period, isolation and extraction of the lipid rafts-like assemblies, the composition of the structures was evaluated using HPLC. Cholesterol and sphingomyelin were detected at 206 nm and phosphatidylcholine was detected at 254 nm. Identification of lactose permease, a typical membrane protein, was done using FTIR. The thermal stability of the produced structures was also determined. Results show that the addition of cholesterol significantly increased both the amount of insoluble lipid rafts-like structures and their stability, and that the availability of a minimum amount of sphingolipid was necessary to produce larger amounts of more stable structures. However, the addition of phospholipids hindered the formation of lipid rafts-like assemblies and those formed were generally less stable.展开更多
Cholesterol,as a common lipid on mammalian cell membranes,plays an important role in the formation of lipid rafts.Recent experiments suggest that the strength of cholesterol's regulation on lipid rafts can be affe...Cholesterol,as a common lipid on mammalian cell membranes,plays an important role in the formation of lipid rafts.Recent experiments suggest that the strength of cholesterol's regulation on lipid rafts can be affected by the length of the unsaturated phospholipid acyl chain on the membrane.In order to understand this observation,a simplified toy model containing three different molecules is proposed in this paper,where the tail length of phospholipids is considered.This model shows the regulation of membrane cholesterol on the phase separation of the lipid mixture and the formation of nano-domains,and also suggests that the configuration entropy of phospholipid tails is an essential factor.展开更多
Emodin [1,3,8-Trihydroxy-6-methylanthraquinone] has been reported to exhibit vascular anti-inflammatory properties.However,the relevant anti-inflammatory mechanisms are not well understood.The present study was design...Emodin [1,3,8-Trihydroxy-6-methylanthraquinone] has been reported to exhibit vascular anti-inflammatory properties.However,the relevant anti-inflammatory mechanisms are not well understood.The present study was design to explore the molecular target(s) of emodin展开更多
Aim: Heating by nanoparticles, which are located in the tissue to be treated, is a well-recognized method in hyperthermic oncology. Our objective is to investigate selective, nanoscopic heating without concentrating e...Aim: Heating by nanoparticles, which are located in the tissue to be treated, is a well-recognized method in hyperthermic oncology. Our objective is to investigate selective, nanoscopic heating without concentrating extra artificial nanoparticles. We have in silico calculation to study the heating of the transmembrane protein clusters (rafts) on cell-membrane. The transmembrane protein domains have significantly higher dielectric constant than their lipid neighborhood in the membrane. This difference causes a local gradient in the Specific Absorption Rate (SAR), which could be a factor of heating of the membranes locally, as well as exciting the receptors for various signal transduction in the cells. We suppose that this process determines the observed cellular effects of modulated electro-hyperthermia (mEHT, trade-name: oncothermia). Materials and Methods: In silico models with highly specialized software (Computer Simulation Technology (CST), Darmstadt, Germany) were performed visualizing the selectivity for the membrane domains. Local raft models were created to simulate the electromagnetic (EM) effect of a 13.56 MHz excitation between two perfect electrical conductor plates, simulating the equipotential conditions of the sides of the membrane in the vicinity of the raft. The simulations were performed with near-field (EQS) solver of CST. The electric field, current density, and electric loss density were monitored by the simulations. The applied material properties and parameters refer to the recent literature. Results: In silico models show ten times higher energy-absorption of the transmembrane domains than that of its lipid-membrane surrounding, and intra- and extracellular neighborhood. Depending on the size, orientation, and location of the membrane rafts, the value of SAR varies, but we use only two simplified models to see the absorption properties. Taking into account the characteristics of the EM field effects we showed that the selective energy-absorption increased further by the cell-cell interactions. The model-calculation could confirm the opportunity of the local membrane heating. Conclusion: Our results indicate the heating in nanoscopic range with energy-absorption by the transmembrane proteins. The heated protein-clusters (membrane rafts) are used the same way as the artificial nanoparticles, while these absorbers are natural parts of the biological system.展开更多
To investigate the dynamics of submersible mussel rafts, the finite element program Aqua-FETM, developed by the University of New Hampshire（UNH）, was applied to rafts moored at the surface and submerged. The submerg...To investigate the dynamics of submersible mussel rafts, the finite element program Aqua-FETM, developed by the University of New Hampshire（UNH）, was applied to rafts moored at the surface and submerged. The submerged configuration is used to reduce wave forcing and to avoid contact with floating ice during winters in northern waters. Each raft consists of three pontoons connected by a grid framework. Rafts are intended to support densely spaced mussel ropes hung from the framework. When submerged, the pontoons are flooded, and the raft is held vertically by floats attached by lines. The computer models were developed in Aqua-FE？ to simulate the effects of waves and current. They were validated by comparison with wave tank results by use of a 1/10 scale raft physical model. Comparisons showed good agreement for the important heave（vertical） and pitch（rotational） motions, though there was a tendency towards conservative results for wave and current drag. Full-scale simulations of surface and submerged single raft and two rafts connected in tandem were performed. Submerged raft wave response was found to be reduced relative to that at the surface for both the single and two-raft configurations. In particular, the vertical motion of mussel rope connection points was significantly reduced by submergence, resulting in reduced potential for mussel drop-off. For example, the maximum vertical velocities of mussel rope attachment points in the submerged two raft case were 7%-20% of the corresponding velocities when at the surface.展开更多
Foundation pit excavation engineering is an old subject full of decision making. Yet, it still deserves further research due to the associated high failure cost and the complexity of the geological conditions and/or t...Foundation pit excavation engineering is an old subject full of decision making. Yet, it still deserves further research due to the associated high failure cost and the complexity of the geological conditions and/or the surrounding existing infrastructure around it. This article overviews the risk control practice of foundation pit excavation projects in close proximity to <span style="font-family:Verdana;">existing</span><span style="font-family:Verdana;"> disconnected piled raft. More focus is given to geotechnical aspects. The review begins with achievements to ensure excavation performance </span><span style="font-family:Verdana;">requirements,</span><span style="font-family:Verdana;"> and follows to discuss the complex </span><span style="font-family:Verdana;">soil structure</span><span style="font-family:Verdana;"> interaction involved among the fundamental components</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">: </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">the retaining wall, mat, piles, cushion, and the soil. After bringing consensus points to practicing engineers and </span><span style="font-family:Verdana;">decision makers</span><span style="font-family:Verdana;">, it then suggests possible future research directions.</span></span></span></span>展开更多
For a long time, lipid rafts have been thought to participate in regulating neurotransmitter release. However, the existence of lipid rafts on synaptic vesicles （SVs） and the mechanism by which exocytosisrelative pr...For a long time, lipid rafts have been thought to participate in regulating neurotransmitter release. However, the existence of lipid rafts on synaptic vesicles （SVs） and the mechanism by which exocytosisrelative proteins distribute on this structure have not been fully investigated. There is also much controversial data concerning rafts on SVs and synaptic vesicle proteins which makes the results difficult to interpret. This study systematically analyzed the existence and properties of lipid rafts on purified SVs by sucrose density gradient centrifugation, cholesterol depletion, and temperature variation. The data reveals that typical lipid rafts on SVs are both cholesterol dependent and temperature sensitive. Previous confusing results may have been caused by improper treatment or side effects of particular reagent. We also screened the lateral distribution of major exocytosis-related SV proteins and found that only the synaptobrevin （syb） and synaptotagmin （syt） produce detectable association with lipid rafts in 1% Triton X-100.展开更多
基金supported by the National Natural Science Foundation of China(Grant no.82074021,82374040)the Beijing Nova Program(Grant no.20240484548).
文摘Background:Diterpenoid esters are considered to be the main toxic components and bioactive constituents of Euphorbia lathyris L.(EL).Euphorbia factors L1(EF1),L2(EF2),and L3(EF3),the main diterpenoid esters of EL,have been found to cause intestinal diarrhea and induce intestinal inflammation in mice.This research aimed to explore the effects of major diterpenoid esters from EL on intestinal inflammation,as well as to clarify their possible targets and molecular mechanisms in vivo and vitro.Methods:Caco-2 cells and BALB/c mice were intervened with EFL1,EFL2,and EFL3,respectively.The expressions of TLR4,NLRP3,NF-κB p65,LXRα,ABCA1,TNF-αand IL-1βwere measured by Real-time PCR and ELISA.Cholesterol efflux levels were examined using cholesterol efflux kit.Flow cytometry was applied to detect lipid rafts abundance.Confocal microscopy was applied to investigate co-localization of lipid rafts and TLR4.Results:Our results revealed that EFL1,EFL2,and EFL3 inhibited LXRα,ABCA1 expression,and cholesterol efflux,promoted colocalization of TLR4 and lipid rafts,and up-regulated TLR4,NLRP3,NF-κB p65,TNF-αand IL-1βexpressions.Conclusion:These findings reveal that the mechanisms by which EFL1,EFL2,and EFL3 induce intestinal inflammation may be associated with LXRα/ABCA1-regulated lipid rafts and TLR4-mediated pathways.
文摘Caveolae and non-caveolar lipid rafts are two types of membrane lipid microdomains that play important roles in insulin-stimulated glucose uptake in adipocytes. In order to ascertain their specific functions in this process, caveolae were ablated by caveolin-1 RNA interference. In Cav-1 RNAi adipocytes, neither insulin-stimulated glucose uptake nor Glut-4 （glucose transporter 4） translocation to membrane lipid microdomains was affected by the ablation of caveolae. With a modified sucrose density gradient, caveolae and non-caveolar lipid rafts could be separated. In the wild-type 3T3- L l adipocytes, Glut-4 was found to be translocated into both caveolae and non-caveolar lipid rafts. However, in Cav1 RNAi adipocytes, Glut-4 was localized predominantly in non-caveolar lipid rafts. After the removal of insulin, caveolaelocalized Glut-4 was internalized faster than non-caveolar lipid raft-associated Glut-4. The internalization of Glut-4 from plasma membrane was significantly decreased in Cav-1 RNAi adipocytes. These results suggest that insulin-stimulated Glut-4 translocation and glucose uptake are caveolae-independent events. Caveolae play a role in the internalization of Glut-4 from plasma membrane after the removal of insulin.
基金supported by a grant from Projects of High-tech Industrialization of Guangdong Province of China,No.2011B010500004a grant from National Financial Major Project of China
文摘Amyloid-beta peptide is the main component of amyloid plaques, which are found in Alzhei- mer＇s disease. The generation and deposition of amyloid-beta is one of the crucial factors for the onset and progression of Alzheimer＇s disease. Lipid rafts are glycolipid-rich liquid domains of the plasma membrane, where certain types of protein tend to aggregate and intercalate. Lipid rafts are involved in the generation of amyloid-beta oligomers and the formation of amyloid-beta peptides. In this paper, we review the mechanism by which lipid rafts disturb the aberrant deg- radative autophagic-lysosomal pathway of amyloid-beta, which plays an important role in the pathological process of Alzheimer＇s disease. Moreover, we describe this mechanism from the view of the Two-system Theory of fasciology and thus, suggest that lipid rafts may be a new target of Alzheimer＇s disease treatment.
基金The National Key R&D Program of China under contract Nos 2016YFC1402104 and 2016YFC1402106the National Natural Science Foundation of China under contract No.41606190+2 种基金the Shandong Natural Science Foundation under contract No.ZR2016DB22the Foundation of Key Laboratory of Integrated Monitoring and Applied Technologies for Marine Harmful Algal Blooms,SOA under contract No.MATHAB 201806the Creative Team Project of the Laboratory for Marine Ecology and Environmental Science,Qingdao National Laboratory for Marine Science and Technology under contract No.LMEES-CTSP-2018-3
文摘Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007.The primary source of the Yellow Sea green tides is the attached algae on the Pyropia aquaculture rafts in the Subei Shoal.Ulva prolifera and Blidingia(Italic)sp.are the main species observed on Pyropia aquaculture rafts in the Subei Shoal.We found that U.prolifera has strong buoyancy and a rapid growth rate,which may explain why it is the dominant species of green tides that occur in the China's sea area of the Yellow Sea.The growth rate of floating U.prolifera was about 20%–31%d–1,which was much higher than Blidingia(Italic)sp.There were about 1.7×104 t of attached algae on the Pyropia aquaculture rafts in May 2012.We found that 39%of attached algae could float when the tide rose in the Subei Shoal,and U.prolifera accounted for 63%of the floating algae.Our analysis estimated that about 4000 t of attached U.prolifera floated into the surrounding waters of the Subei Shoal during the recycling period of aquaculture rafts.These results suggest that the initial floating biomass of large-scale green tides in the Yellow Sea is determined by the U.prolifera biomass attached to Pyropia aquaculture rafts,further impacting the scale of the green tide。
基金The Science and Technology Foundation of Shenyang City(Grant No.RC170545)the Science and Technology Foundation of Liaoning Province(Grant No.20170540995)the National Science Foundation of China(Grant No.81302313)
文摘Apatinib,an oral anti-angiogenic agent,has been shown to have anti-cancer effects for several cancer cell types.However,little is known about the direct anti-tumor activity of apatinib for breast cancer cells.Herein,the direct effect of apatinib on breast cancer cells and its mechanism of action were assessed.Cell viability was measured with a Cell Counting Kit-8.Cell apoptosis was assessed by flow cytometry.The expression of caspase-8 and the cleavage of poly ADP ribose polymerase were assessed by Western blotting analysis.Lipid rafts and Fas distribution were determined by immunofluorescence microscopy.Apatinib suppressed breast cancer cell proliferation in a dose-dependent manner.Furthermore,apatinib enhanced the aggregation of lipid rafts and the redistribution of Fas into lipid rafts.Pretreatment with methyl-β-cyclodextrin,a cholesterol-sequestering agent,significantly reversed Fas redistribution and apatinib-induced apoptosis.In conclusion,these results demonstrated that apatinib induced apoptosis of breast cancer cells partially through recruitment of Fas into lipid rafts.
基金supported by aBBSRC grant (LAK, RDP)a BBSRC-funded PhDstudentship (FJH)
文摘GP64 is the major envelope glycoprotein associated with the budded virus (BV) of Autographa californica nucleopolyhedrovirus (AcMNPV) and is essential for attachment and budding of BV particles. Confocal microscopy and flotation assays established the presence of lipid raft domains within the plasma membranes of AcMNPV-infected Sf9 cells and suggested the association of GP64 with lipid rafts during infection. GP64 and filamentous actin (F-actin) were found to co-localise at the cell cortex at 24 and 48 hpi and an additional restructuring of F-actin during infection was visualised, resulting in a strongly polarised distribution of both F-actin and GP64 at the cell cortex. Depletion of F-actin, achieved by treatment of Sf9 cells with latrunculin B (LB), resulted in the redistribution of GP64 with significant cytoplasmic aggregation and reduced presence at the plasma membrane. Treatment with LB also resulted in reduced production of BV in Sf9 cells. Analysis of virus gene transcription confirmed this reduction was not due to decreased trafficking of nucleocapsids to the nucleus or to decreased production of infectious progeny nucleocapsids. Reduced BV production due to a lack of GP64 at the plasma membrane of AcMNPV-infected Sf9 cells treated with LB, suggests a key role for F-actin in the egress of BV.
文摘Lipid rafts are sterol and sphingolipid rich membrane domains that possibly may play roles in multiple cellular processes. These domains are still the matter of debate and it is still unknown by which mechanism if any and organisms promote their formation. This study centers on the ease of in vitro formation of lipid rafts-like structures as it relates to the relative availability of sphingolipids, phospholipids, cholesterol, and membrane proteins. Following a 12 h incubation period, isolation and extraction of the lipid rafts-like assemblies, the composition of the structures was evaluated using HPLC. Cholesterol and sphingomyelin were detected at 206 nm and phosphatidylcholine was detected at 254 nm. Identification of lactose permease, a typical membrane protein, was done using FTIR. The thermal stability of the produced structures was also determined. Results show that the addition of cholesterol significantly increased both the amount of insoluble lipid rafts-like structures and their stability, and that the availability of a minimum amount of sphingolipid was necessary to produce larger amounts of more stable structures. However, the addition of phospholipids hindered the formation of lipid rafts-like assemblies and those formed were generally less stable.
基金fiancial support from the National Natural Science Foundation of China(NSFC No.61475196)。
文摘Cholesterol,as a common lipid on mammalian cell membranes,plays an important role in the formation of lipid rafts.Recent experiments suggest that the strength of cholesterol's regulation on lipid rafts can be affected by the length of the unsaturated phospholipid acyl chain on the membrane.In order to understand this observation,a simplified toy model containing three different molecules is proposed in this paper,where the tail length of phospholipids is considered.This model shows the regulation of membrane cholesterol on the phase separation of the lipid mixture and the formation of nano-domains,and also suggests that the configuration entropy of phospholipid tails is an essential factor.
基金supported by National Natural Science Foundation of China,30700151Youth Investigator Fund from UESTC,Y02018023601062
文摘Emodin [1,3,8-Trihydroxy-6-methylanthraquinone] has been reported to exhibit vascular anti-inflammatory properties.However,the relevant anti-inflammatory mechanisms are not well understood.The present study was design to explore the molecular target(s) of emodin
文摘Aim: Heating by nanoparticles, which are located in the tissue to be treated, is a well-recognized method in hyperthermic oncology. Our objective is to investigate selective, nanoscopic heating without concentrating extra artificial nanoparticles. We have in silico calculation to study the heating of the transmembrane protein clusters (rafts) on cell-membrane. The transmembrane protein domains have significantly higher dielectric constant than their lipid neighborhood in the membrane. This difference causes a local gradient in the Specific Absorption Rate (SAR), which could be a factor of heating of the membranes locally, as well as exciting the receptors for various signal transduction in the cells. We suppose that this process determines the observed cellular effects of modulated electro-hyperthermia (mEHT, trade-name: oncothermia). Materials and Methods: In silico models with highly specialized software (Computer Simulation Technology (CST), Darmstadt, Germany) were performed visualizing the selectivity for the membrane domains. Local raft models were created to simulate the electromagnetic (EM) effect of a 13.56 MHz excitation between two perfect electrical conductor plates, simulating the equipotential conditions of the sides of the membrane in the vicinity of the raft. The simulations were performed with near-field (EQS) solver of CST. The electric field, current density, and electric loss density were monitored by the simulations. The applied material properties and parameters refer to the recent literature. Results: In silico models show ten times higher energy-absorption of the transmembrane domains than that of its lipid-membrane surrounding, and intra- and extracellular neighborhood. Depending on the size, orientation, and location of the membrane rafts, the value of SAR varies, but we use only two simplified models to see the absorption properties. Taking into account the characteristics of the EM field effects we showed that the selective energy-absorption increased further by the cell-cell interactions. The model-calculation could confirm the opportunity of the local membrane heating. Conclusion: Our results indicate the heating in nanoscopic range with energy-absorption by the transmembrane proteins. The heated protein-clusters (membrane rafts) are used the same way as the artificial nanoparticles, while these absorbers are natural parts of the biological system.
基金financially supported by the Small Business Innovation Research(SBIR)program of the USDA National Institute for Food and Agriculture(NIFA)(Grant No.2013-33610-21190)to Pemaquid Mussel FarmsDuring her time at the University of New Hampshire where this study was completedsupported by a graduate student fellowship funded by the People’s Republic of China
文摘To investigate the dynamics of submersible mussel rafts, the finite element program Aqua-FETM, developed by the University of New Hampshire（UNH）, was applied to rafts moored at the surface and submerged. The submerged configuration is used to reduce wave forcing and to avoid contact with floating ice during winters in northern waters. Each raft consists of three pontoons connected by a grid framework. Rafts are intended to support densely spaced mussel ropes hung from the framework. When submerged, the pontoons are flooded, and the raft is held vertically by floats attached by lines. The computer models were developed in Aqua-FE？ to simulate the effects of waves and current. They were validated by comparison with wave tank results by use of a 1/10 scale raft physical model. Comparisons showed good agreement for the important heave（vertical） and pitch（rotational） motions, though there was a tendency towards conservative results for wave and current drag. Full-scale simulations of surface and submerged single raft and two rafts connected in tandem were performed. Submerged raft wave response was found to be reduced relative to that at the surface for both the single and two-raft configurations. In particular, the vertical motion of mussel rope connection points was significantly reduced by submergence, resulting in reduced potential for mussel drop-off. For example, the maximum vertical velocities of mussel rope attachment points in the submerged two raft case were 7%-20% of the corresponding velocities when at the surface.
文摘Foundation pit excavation engineering is an old subject full of decision making. Yet, it still deserves further research due to the associated high failure cost and the complexity of the geological conditions and/or the surrounding existing infrastructure around it. This article overviews the risk control practice of foundation pit excavation projects in close proximity to <span style="font-family:Verdana;">existing</span><span style="font-family:Verdana;"> disconnected piled raft. More focus is given to geotechnical aspects. The review begins with achievements to ensure excavation performance </span><span style="font-family:Verdana;">requirements,</span><span style="font-family:Verdana;"> and follows to discuss the complex </span><span style="font-family:Verdana;">soil structure</span><span style="font-family:Verdana;"> interaction involved among the fundamental components</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">: </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">the retaining wall, mat, piles, cushion, and the soil. After bringing consensus points to practicing engineers and </span><span style="font-family:Verdana;">decision makers</span><span style="font-family:Verdana;">, it then suggests possible future research directions.</span></span></span></span>
基金Supported by the National Key Basic Research and Development (973) Program of China (No. 2004CB720005)
文摘For a long time, lipid rafts have been thought to participate in regulating neurotransmitter release. However, the existence of lipid rafts on synaptic vesicles （SVs） and the mechanism by which exocytosisrelative proteins distribute on this structure have not been fully investigated. There is also much controversial data concerning rafts on SVs and synaptic vesicle proteins which makes the results difficult to interpret. This study systematically analyzed the existence and properties of lipid rafts on purified SVs by sucrose density gradient centrifugation, cholesterol depletion, and temperature variation. The data reveals that typical lipid rafts on SVs are both cholesterol dependent and temperature sensitive. Previous confusing results may have been caused by improper treatment or side effects of particular reagent. We also screened the lateral distribution of major exocytosis-related SV proteins and found that only the synaptobrevin （syb） and synaptotagmin （syt） produce detectable association with lipid rafts in 1% Triton X-100.
