Kinetics of lipid raft formation at lipid monolayer-bilayer junction probed by surface plasmon resonance

Ryu, Yong-Sang,Yun, Hansik,Chung, Taerin,Suh, Jeng-Hun,Kim, Sungho,Lee, Kyookeun,Wittenberg, Nathan J.,Oh, Sang-Hyun,Lee, Byoungho,Lee, Sin-Doo Elsevier Applied Science 2019 Biosensors & bioelectronics Vol. No.

<P><B>Abstract</B></P> <P>A label-free, non-dispruptive, and real-time analytical device to monitor the dynamic features of biomolecules and their interactions with neighboring molecules is an essential prerequisite for biochip- and diagonostic assays. To explore one of the central questions on the lipid-lipid interactions in the course of the liquid-ordered (<I>l</I> <SUB> <I>o</I> </SUB>) domain formation, called rafts, we developed a method of reconstituting continuous but spatially heterogeneous lipid membrane platforms with molayer-bilayer juntions (MBJs) that enable to form the <I>l</I> <SUB> <I>o</I> </SUB> domains in a spatiotemporally controlled manner. This allows us to detect the time-lapse dynamics of the lipid-lipid interactions during raft formation and resultant membrane phase changes together with the raft-associated receptor-ligand binding through the surface plasmon resonance (SPR). For cross-validation, using epifluorescence microscopy, we demonstrated the underlying mechanisms for raft formations that the infiltration of cholesterols into the sphingolipid-enriched domains plays a crucial roles in the membrane phase-separation. Our membrane platform, being capable of monitoring dynamic interactions among lipids and performing the systematic optical analysis, will unveil physiological roles of cholesterols in a variety of biological events.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Continuous but spatially heterogeneous membranes were probed by the SPR for monitoring the kinetic behavior of lipid-lipid interactions </LI> <LI> The accompanying biochemical activity of ligand-receptor binding. Our monolayer-bilayer junction methodology of manipulating the bio-membranes enables to precisely control the phase-separation of l<SUB>o</SUB> domains at pre-defined regions on a SPR-based biochip and to unveil the kinetics of the raft formation together with raft-associated receptor-ligand interactions </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Continuous but spatially heterogeneous membranes were probed by the SPR for monitoring the kinetic behavior of lipid-lipid interactions (a) and the accompanying biochemical activity of ligand-receptor binding. Our monolayer-bilayer junction methodology of manipulating the bio-membranes enables to precisely control the phase-separation of <I>l</I> <SUB> <I>o</I> </SUB> domains at pre-defined regions (b) on a SPR-based biochip and to unveil the kinetics of the raft formation together with raft-associated receptor-ligand interactions (c).</P> <P>[DISPLAY OMISSION]</P>

피지내 과산화지질이 기미와 여드름의 치료에 미치는 영향

오지원,함정희 梨花女子大學校 醫科大學 醫科學硏究所 1991 EMJ (Ewha medical journal) Vol.14 No.3

To evaluate correlation between the amounts of lipid peroxide in skin surface lipid and clinical aspect of lipid-relating cutaneous disorders, such as melasma and acne, skin surface lipid samples were collected by using cup method from the faces of 20 acne women and 20 melasma women, before and 3 months after topical treatment with 2% hydroquinone and 2.5% benzoyl peroxide, respectively. The amounts of total lipids and lipid peroxide in skin surface lipid were measured by spectrophotometer and statistically analyzed by student's t-test. The results were as follows; 1) Before treatmentin comparison with control group, melasma group showed increase of the amounts of lipid peroxide and the ratio of lipid peroxide to total lipids. But acne group showed significant increase of the ratio of lipid peroxide to total lipids as well as the amounts of total lipids and lipid peroxide. 2) After treatment, in comparison with pretreatment, melasma group showed significant decrease of the amounts of lipid peroxide and the ratio of lipid peroxide to total lipids. And in acne group, the amounts of total lipids and lipid peroxide were also decreased significantly. The amounts of lipid peroxide in skin surface lipid decreased at the time of improvements of clinical aspects in melasma and acne. This data suggest that clinical aspect of melasma and acne is related to the amounts of lipid peroxide in skin surface lipid.

Lipid turnover between membrane lipids and neutral lipids via inhibition of diacylglyceryl <i>N</i>,<i>N</i>,<i>N</i>-trimethylhomoserine synthesis in <i>Chlamydomonas reinhardtii</i>

Lee, Jun-Woo,Shin, Sang-Yoon,Kim, Hee-Sik,Jin, EonSeon,Lee, Hyung-Gwan,Oh, Hee-Mock Elsevier 2017 Algal research Vol.27 No.-

<P><B>Abstract</B></P> <P> <I>Chlamydomonas reinhardtii</I> of the microalgal model species lacks phosphatidylcholine (PC), and PC is replaced by diacylglyceryl <I>N</I>,<I>N</I>,<I>N</I>-trimethylhomoserine (DGTS). DGTS is a betaine lipid that is placed in the endoplasmic reticulum (ER) and is synthesized by a single gene, <I>BTA1</I>. In this study, we aimed to ascertain the turnover between membrane and neutral lipids via <I>BTA1</I> knockdown transformants. Transgenic lines CrBta-hm13 and CrBta-hm31 were 80% and 60% downregulated in <I>BTA1</I> gene expression levels, respectively. Both transformants had half the amount of DGTS, which coincided with decreased monogalactosyldiacylglycerol (MGDG), which was increased approximately threefold in neutral lipids. While the reduction of DGTS was shown to arise from inhibition of DGTS synthesis, decreased MGDG was affected by internal stress, such as ER stress, which was induced to have a decreased amount of DGTS in the ER. However, galactolipids, except for MGDG, and phospholipids in the transformants were maintained at similar levels. In the transformants, the molar proportion of C16:4 and C18:3(9,12,15), which are the major fatty acids of MGDG, was significantly increased in triacylglycerol (TAG) because of MGDG degradation. Thus, lipid turnover arising from the downregulation of DGTS and induction of ER stress caused a decrease in DGTS and MGDG, which generated a synergy effect on the accumulation of TAG. This study implies that genetic modification of a membrane lipid synthesis pathway could not only be a suitable approach to target accumulation of TAG, but could also suggest a mechanism for the lipid turnover between membrane lipids and neutral lipids.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The expression of <I>BTA1</I> was downregulated by amiRNAs in CrBta-hm13 (by 80%) and CrBta-hm31 (by 60%). </LI> <LI> DGTS and MGDG were decreased in both transformants, whereas neutral lipids were increased ca. 3-fold. </LI> <LI> Lipid turnover in the form of TAG accumulation was caused by DGTS reduction and ER stress induction. </LI> <LI> The increased neutral lipids and decreased glycolipids in CrBta-hm13 are suitable for the biodiesel production. </LI> </UL> </P>

Lipid emulsion 투여가 면역계와 감염에 미치는 영향에 관한 문헌적 고찰

김정식,박광준,박경호,신완균,조남춘 한국병원약사회 1998 병원약사회지 Vol.15 No.3

Lipid emulsion is an integral component of total parenteral nutrition (TPN). Not only are these emulsions a valuable calorie source but they also provide a supply of essential fatty acids. Children have large energy requirement to grow up, so energy supply with lipid emulsions is especially important in children. But, it is supposed that lipid emulsions suppress the immune function and there has been controversy about the effect of lipid emulsion on immune system. The reluctancy to administer lipid emulsion as well as no lipid emulsion administration for long period has been observed in our hospital because it has been suggested that lipid emulsions possess immunosuppressive properties. This review analyzes the effect of lipid emulsion on immune system. For this purpose, we reviewd 25 relevant studies. Studies on the effect of lipid emulsion on polymorphonuclear (PMN) cell, lymphocyte, monocyte or macrophage have been evaluated. The studies that show lipid emulsions cause an impairment of PMN cell and lymphocyte function were most in vitro studies. And many of these studies have been performed under highly artificial condition in which the dose of lipid emulsion has been inappropriate to clinical practice. In vivo studies show that lipid emulsions no effect on PMN function or enhance the function of PMN on the contrary. The studies that investigate the effect of lipid emulsion on lymphocyte showed conflicting results. Ota et al were unable to detect significant immunologic changes following lipid emulsion infusion. Conversely it has been observed that following a course of preoperative lipid-based TPN in patient with cancer of gastrointestinal tract lymphocyte function was impaired. But, these studies performed in gastrointestinal cancer patient who have already depressed lymphocyte function and chose lipid-based regimen in which lipid emulsion provided more than a half of calorie. In the studies that show lipid emulsion have no immunosuppressive effects, lipid was administered in a rate or dose less than maximum recommended rate or dose. From the studies reviewed, it can be deduced that lipid emulsion do not supress immune system when administered in the recommended dosage.

Effects of Skin Surface Lipids on Skin Health

Faqing Feng,Laiji Ma,Zhaohui Qu,Yinmao Dong,Fan Yi 한국피부과학연구원 2019 아시안뷰티화장품학술지 Vol.17 No.1

Skin surface lipids are composed of sebaceous glands secreting lipids and epidermal disintegration lipids. The main components include triglycerides, free fatty acids, wax esters, squalene, cholesterol and so on. Skin surface lipids adhere to the surface of the skin and rely on their physical, chemical and biological properties to be important for skin health. This article reviews the relevant literatures at home and abroad, briefly describes the effects of skin surface lipids on skin moisturization, anti-oxidation and maintenance of micro-ecology, and mainly introduces the oxidation/metabolism of squalene/free fatty acids, which is more affected by external harmful factors than other skin surface lipids. As well as, the effects on skin health of squalene oxidation products and triglyceride metabolites are introduced. Above all, the oxidation/metabolism of skin surface lipids and the role of their products are illustrated in order to reveal the relationship between skin surface lipids and skin health and to provide a theoretical reference for the research and development of cosmetics by regulating skin surface lipids. Keywords: Skin surface lipids, Squalene, Free fatty acids, Oxidation

Observation of chitosan coated lipid nanoparticles with different lipid compositions under simulated <i>in vitro</i> digestion system

Shin, Gye Hwa,Kim, Jun Tae IRL Press 2018 Food hydrocolloids Vol.84 No.-

<P><B>Abstract</B></P> <P>The effects of lipid composition and chitosan coating on lipid digestion ability were investigated using a simulated <I>in vitro</I> digestion system, including oral, gastric, and small intestine stages. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) were prepared with only palm oil and the mixture of palm oil and medium-chain triglyceride (MCT) oil, respectively. Chitosan-coated SLNs (CS-SLNs) and NLCs (CS-NLCs) were prepared with a drop-wise method. CS-NLCs were more completely digested than the NLCs, while the NLCs showed higher free fatty acid release than SLNs. Chitosan coating increased the particle size of both SLNs and NLCs from 100.0 to 104.9 nm to 130.0 and 146.5 nm, respectively. Chitosan coating also increased the initial digestion rate of NLCs by modulating lipid droplet aggregation. But, chitosan coating showed little impact on the digestion of SLNs because SLNs did not strongly impact the lipid droplet aggregation state. These results have important implications for the fabrication of functional foods and beverages to achieve control of lipid digestion in the gastrointestinal tract.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Four lipid nanoparticles were prepared to compare the lipid digestion. </LI> <LI> The particles were subjected to an <I>in vitro</I> simulated digestive system and compared. </LI> <LI> NLC showed more rapid digestion than SLN due to the liquid lipid. </LI> <LI> Free fatty acid release profile of CS-SLN was almost same to that of SLN. </LI> <LI> CS-NLC showed greater free fatty acid release than NLC. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Culture Tube Method for the Determination of Total Cholesterol in Egg Yolk Lipid

Ha, Yeong-Lae,Kim, Jeong-Ok The Korean Society of Food Science and Nutrition 1994 한국식품영양과학회지 Vol.23 No.6

A simple, reproducible , and accurate enzymatic method using a cholesterol assay kit was developed to quantify total cholesterol content in egg yolk. Total egg yolk lipid was extracted with hexane : isopropanol(3 : 2, v/v) mixture. Samples containing various amount of the total lipid(0-3mg) in optically identifical culture tubes were reacted for 10 min in a water bath (37$^{\circ}C$) with the enzyme solution (5ml) from the cholesterol assay kit. Cholesterol content of the reaction mixturesin culture tubes was spectrophotometrically determined by two different ways : (1) using the culture tube as a curvette(designate culture tube method ; CTM) and (2) the quartz cvette containing the reaction mixture transferred from the culture tube (designate standard cvette method, SCM). CTM revealed lower cholesterol content in 0.1-1.0mg lipid sample range that SCM did, but not significant. For more than 2.0mg lipid sample, CTM gave significantly (p<0.01) lower cholesterol content relative to that by SCM, suggesting that SCM give a false positive result from the sample containing more than 2 mg lipid due to the interference of absorbance by lipid dispersed in the reaction solution . Cholesterol content of less than 1.0mg lipid sample by CTM was proportional to the amount of lipid used, but its linear relationship was not seen in more than 2mg lipid sample. Thus, to determine the appropriate lipid amounts (mg) analyzed . A constant level (41$\mu\textrm{g}$/mg) of cholesterol concentration was observed from the sample containing 0.1-1mg lipid. after which the cholesterol level was dropped to less than 41$\mu\textrm{g}$ /mg. Cholesterol concentration in egg yolk samples quantified by CTM was in accordance with that by GC method. These results suggest that CTM is an useful method for the quantification of cholesterol in egg yolk lipid and other lipids as well.

Optimal Dietary Protein and Lipid Levels for Growth of Long-nosed Barbel, Hemibarbus longirostris

Kim, Yi-Oh,Hwang, Gyu-Deok,Lee, Sang-Min The Korean Society of Fisheries and Aquatic Scienc 2009 Fisheries and Aquatic Sciences Vol.12 No.4

A 10-week feeding trial with four dietary protein levels (22%, 32%, 42% and 52%) and two dietary lipid levels (8% and 17%) was conducted to investigate the optimum dietary protein and lipid levels for growth of long-nosed barbel fingerlings. Survival rate of fish was not affected by either the dietary protein or the dietary lipid level. Weight gain and feed efficiency were affected by the dietary protein level (P<0.01), but not by the lipid level, and increased with the dietary protein level at the both lipid levels. Weight gain and feed efficiency of fish fed the 52% protein diets with 8-17% dietary lipids were not significantly different from those of fish fed the 42% protein diets with 8-17% dietary lipids and 32% protein diet with 17% dietary lipid. Daily feed intake of fish was not affected by either dietary protein or dietary lipid level. Protein efficiency ratio and protein retention rate of fish fed the 32% protein diet with 17% dietary lipid were significantly higher than those of fish fed the 52% protein diets with 8-17% dietary lipids. Moisture content of fish fed the diets containing 8% lipid were higher than those of fish fed the diets containing 17% dietary lipid at each protein level. Crude lipid content of fish fed the diets containing 17% dietary lipid were higher than that of fish the fed the diet containing 8% dietary lipid at each protein level. The results of this study indicated that 32% protein and 17% lipid could be the optimum dietary level for growth of juvenile long-nosed barbel.

Optimal Dietary Protein and Lipid Levels for Growth of Long-nosed Barbel, Hemibarbus longirostris

김이오,황규덕,이상민 한국수산과학회 2009 Fisheries and Aquatic Sciences Vol.12 No.4

A 10-week feeding trial with four dietary protein levels (22%, 32%, 42% and 52%) and two dietary lipid levels (8% and 17%) was conducted to investigate the optimum dietary protein and lipid levels for growth of long-nosed barbel fingerlings. Survival rate of fish was not affected by either the dietary protein or the dietary lipid level. Weight gain and feed efficiency were affected by the dietary protein level (P<0.01), but not by the lipid level, and increased with the dietary protein level at the both lipid levels. Weight gain and feed efficiency of fish fed the 52% protein diets with 8-17% dietary lipids were not significantly different from those of fish fed the 42% protein diets with 8-17% dietary lipids and 32% protein diet with 17% dietary lipid. Daily feed intake of fish was not affected by either dietary protein or dietary lipid level. Protein efficiency ratio and protein retention rate of fish fed the 32% protein diet with 17% dietary lipid were significantly higher than those of fish fed the 52% protein diets with 8-17% dietary lipids. Moisture content of fish fed the diets containing 8% lipid were higher than those of fish fed the diets containing 17% dietary lipid at each protein level. Crude lipid content of fish fed the diets containing 17% dietary lipid were higher than that of fish the fed the diet containing 8% dietary lipid at each protein level. The results of this study indicated that 32% protein and 17% lipid could be the optimum dietary level for growth of juvenile long-nosed barbel.

Effects of Dietary Protein and Lipid Levels on Growth, Feed Utilization and Body Composition of Adult Starry Flounder (Platichthys stellatus)

이종하,조성환,임한규,이상민,김경덕 한국수산과학회 2004 Fisheries and Aquatic Sciences Vol.7 No.4

A 25-week feeding trial of two dietary protein (47 and 52%) and three dietary lipid level (7, 12 and 17%) factorial design with three replications were conducted to determine effects of dietary protein and lipid levels on growth, feed utilization and body composition of adult starry flounder (Platichthys stellatus), average initial weight 332 g, during the winter season. Survival of fish was not affected by either dietary protein or dietary lipid level. Weight gain, feed efficiency and protein efficiency ratio improved with dietary protein and lipid levels except for those of fish fed the 52% protein diet with 17% lipid. The best growth and feed utilization were observed in the 52% protein diet with 12% lipid, but were not significantly different from those of fish fed the 52% protein diet with 17% lipid or the 47% protein diets with 17% lipid levels. Hepatosomatic and visceralsomatic indexes were significantly influenced by dietary protein level, but not by dietary lipid level. None of moisture, crude protein, crude lipid, or glycogen contents of dorsal muscle or liver in starry flounder except for crude lipid in dorsal muscle was significantly influenced by either dietary protein or dietary lipid level. Plasma cholesterol concentration was significantly influenced by both dietary protein and dietary lipid levels. The results of this study suggest that the diets containing 47% protein with 17% lipid or 52% protein with 12-17% lipid are optimal for growth and feed utilization of adult starry flounder under these experimental conditions.