Quantitative analysis of brain and spinach leaf lipids employing silicic acid column chromatography and acetone for elution of glycolipids

Hydroxy fatty acids in the surface Earth system

Lipids are ubiquitous and highly abundant in a wide range of organisms and have been found in various types of environmental media. These molecules play a crucial role as organic tracers by providing a chemical perspective on viewing the material world, as well as offering a wealth of information on metabolic activities. Among the diverse lipid compounds, hydroxy fatty acids (HFAs) with one to multiple hydroxyl groups attached to the carbon chain stand out as important biomarkers for different sources of organic matter. HFAs are widespread in nature and are involved in biotransformation and oxidation processes in living organisms. The unique chemical and physical properties attributed to the hydroxyl group make HFAs ideal biomarkers in biomedicine and environmental toxicology, as well as organic geochemistry. The molecular distribution patterns of HFAs can be unique and diagnostic for a given class of organisms, including animals, plants, and microorganisms. Thus, HFAs can act as a valuable proxy for understanding the ecological relationships between different organisms and their environment. Furthermore, HFAs have numerous industrial applications due to their higher reactivity, viscosity, and solvent miscibility. This review paper integrates the latest research on the sources and chemical analyses of HFAs, as well as their applications in industrial/medicinal production and as biomarkers in environmental studies. This review article also provides insights into the biogeochemical cycles of HFAs in the surface Earth system, highlighting the importance of these compounds in understanding the complex interactions between living organisms and the environment.

Insights into the mechanisms of interaction between inhalable lipid-polymer hybrid nanoparticles and pulmonary surfactant

Pulmonary delivery of small interfering RNA (siRNA) using nanoparticle-based delivery systems is promising for local treatment of respiratory diseases. We designed dry powder inhaler formulations of siRNA-loaded lipid-polymer hybrid nanoparticles (LPNs) with aerosolization properties optimized for inhalation therapy. Interactions between LPNs and pulmonary surfactant (PS) determine the fate of inhaled LPNs, but interaction mechanisms are unknown. Here we used surface-sensitive techniques to study how physicochemical properties and pathological microenvironments influence interactions between siRNA-loaded LPNs and supported PS layers. PS was deposited on SiO₂ surfaces as single bilayer or multilayers and characterized using quartz crystal microbalance with dissipation monitoring and Fourier-transform infrared spectroscopy with attenuated total reflection. Immobilization of PS as multilayers, resembling the structural PS organization in the alveolar subphase, effectively reduced the relative importance of interactions between PS and the underlying surface. However, the binding affinity between PS and LPNs was identical in the two models. The physicochemical LPN properties influenced the translocation pathways and retention time of LPNs. Membrane fluidity and electrostatic interactions were decisive for the interaction strength between LPNs and PS. Experimental conditions reflecting pathological microenvironments promoted LPN deposition. Hence, these results shed new light on design criteria for LPN transport through the air-blood barrier.

Polyhydroxyalkanoate Nanoparticles for Pulmonary Drug Delivery: Interaction with Lung Surfactant

Polyhydroxyalkanoates (PHA) are polyesters produced intracellularly by many bacterial species as energy storage materials, which are used in biomedical applications, including drug delivery systems, due to their biocompatibility and biodegradability. In this study, we evaluated the potential application of this nanomaterial as a basis of inhaled drug delivery systems. To that end, we assessed the possible interaction between PHA nanoparticles (NPs) and pulmonary surfactant using dynamic light scattering, Langmuir balances, and epifluorescence microscopy. Our results demonstrate that NPs deposited onto preformed monolayers of DPPC or DPPC/POPG bind these surfactant lipids. This interaction facilitated the translocation of the nanomaterial towards the aqueous subphase, with the subsequent loss of lipid from the interface. NPs that remained at the interface associated with liquid expanded (LE)/tilted condensed (TC) phase boundaries, decreasing the size of condensed domains and promoting the intermixing of TC and LE phases at submicroscopic scale. This provided the stability necessary for attaining high surface pressures upon compression, countering the destabilization induced by lipid loss. These effects were observed only for high NP loads, suggesting a limit for the use of these NPs in pulmonary drug delivery.

Dietary PlsEtn Ameliorates Colon Mucosa Inflammatory Stress and ACF in DMH-Induced Colon Carcinogenesis Mice: Protective Role of Vinyl Ether Linkage

Ethanolamine plasmalogen (PlsEtn), a sub-class of ethanolamine glycerophospholipids (EtnGpl), is a universal phospholipid in mammalian membranes. Several researchers are interested in the relationship between colon carcinogenesis and colon PlsEtn levels. Here, we evaluated the functional role of dietary purified EtnGpl from the ascidian muscle (87.3 mol% PlsEtn in EtnGpl) and porcine liver (7.2 mol% PlsEtn in EtnGpl) in 1,2-dimethylhydrazine (DMH)-induced aberrant crypt foci (ACF) in vivo, and elucidated the possible underlying mechanisms behind it. Dietary EtnGpl-suppressed DMH-induced aberrant crypt with one foci (AC1) and total ACF formation (P < 0.05). ACF suppression by dietary ascidian muscle EtnGpl was higher compared with dietary porcine liver EtnGpl. Additionally, dietary EtnGpl decreased DMH-induced oxidative damage, overproduction of TNF-α, and expression of apoptosis-related proteins in the colon mucosa. The effect of dietary ascidian muscle EtnGpl showed superiority compared with dietary porcine liver EtnGpl. Our results demonstrate the mechanisms by which dietary PlsEtn suppress ACF formation and apoptosis. Dietary PlsEtn attained this suppression by reducing colon inflammation and oxidative stress hence a reduction in DMH-induced intestinal impairment. These findings provide new insights about the functional role of dietary PlsEtn during colon carcinogenesis.

A Broad-Spectrum Antiviral Peptide Blocks Infection of Viruses by Binding to Phosphatidylserine in the Viral Envelope

The ongoing threat of viral infections and the emergence of antiviral drug resistance warrants a ceaseless search for new antiviral compounds. Broadly-inhibiting compounds that act on elements shared by many viruses are promising antiviral candidates. Here, we identify a peptide derived from the cowpox virus protein CPXV012 as a broad-spectrum antiviral peptide. We found that CPXV012 peptide hampers infection by a multitude of clinically and economically important enveloped viruses, including poxviruses, herpes simplex virus-1, hepatitis B virus, HIV-1, and Rift Valley fever virus. Infections with non-enveloped viruses such as Coxsackie B3 virus and adenovirus are not affected. The results furthermore suggest that viral particles are neutralized by direct interactions with CPXV012 peptide and that this cationic peptide may specifically bind to and disrupt membranes composed of the anionic phospholipid phosphatidylserine, an important component of many viral membranes. The combined results strongly suggest that CPXV012 peptide inhibits virus infections by direct interactions with phosphatidylserine in the viral envelope. These results reiterate the potential of cationic peptides as broadly-acting virus inhibitors.

A Genome-Wide Haploid Genetic Screen Identifies Heparan Sulfate-Associated Genes and the Macropinocytosis Modulator TMED10 as Factors Supporting Vaccinia Virus Infection

Vaccinia virus is a promising viral vaccine and gene delivery candidate and has historically been used as a model to study poxvirus-host cell interactions. We employed a genome-wide insertional mutagenesis approach in human haploid cells to identify host factors crucial for vaccinia virus infection. A library of mutagenized HAP1 cells was exposed to modified vaccinia virus Ankara (MVA). Deep-sequencing analysis of virus-resistant cells identified host factors involved in heparan sulfate synthesis, Golgi organization, and vesicular protein trafficking. We validated EXT1, TM9SF2, and TMED10 (TMP21/p23/p24δ) as important host factors for vaccinia virus infection. The critical roles of EXT1 in heparan sulfate synthesis and vaccinia virus infection were confirmed. TM9SF2 was validated as a player mediating heparan sulfate expression, explaining its contribution to vaccinia virus infection. In addition, TMED10 was found to be crucial for virus-induced plasma membrane blebbing and phosphatidylserine-induced macropinocytosis, presumably by regulating the cell surface expression of the TAM receptor Axl.IMPORTANCE Poxviruses are large DNA viruses that can infect a wide range of host species. A number of these viruses are clinically important to humans, including variola virus (smallpox) and vaccinia virus. Since the eradication of smallpox, zoonotic infections with monkeypox virus and cowpox virus are emerging. Additionally, poxviruses can be engineered to specifically target cancer cells and are used as a vaccine vector against tuberculosis, influenza, and coronaviruses. Poxviruses rely on host factors for most stages of their life cycle, including attachment to the cell and entry. These host factors are crucial for virus infectivity and host cell tropism. We used a genome-wide knockout library of host cells to identify host factors necessary for vaccinia virus infection. We confirm a dominant role for heparin sulfate in mediating virus attachment. Additionally, we show that TMED10, previously not implicated in virus infections, facilitates virus uptake by modulating the cellular response to phosphatidylserine.

Seeds of Centranthus ruber and Valeriana officinalis Contain Conjugated Linolenic Acids with Reported Antitumor Effects

Conjugated linolenic acids (CLNs) are naturally occurring fatty acids that are believed to have anticancer properties. In this study, we examined various plant seeds from herbs to discover seed oils containing CLNs. The ultraviolet spectra of total lipids from these seeds were measured. An absorption maximum around 270 nm was observed in seed oils belonging to the Valerianaceae family (Centranthus ruber and Valeriana officinalis). When the fatty acid compositions of these seed oils were measured, CLNs were detected. By silica column chromatography, neutral lipids (NLs), glycolipids, and phospholipids were eluted from seed oils of C. ruber and V. officinalis. Then, fatty acid compositions of these fractions were measured. This revealed that most of the CLNs in these seed oils existed in the NL fraction. When the NL fractions of these seed oils were reacted with lipase, CLNs showed good sensitivity to lipase hydrolysis. This suggested that the CLNs in the seed oils of C. ruber and V. officinalis existed predominantly at the sn-1,3 position of triacylglycerol and less at the sn-2 position. These results suggested that the CLNs from the seed oils of C. ruber and V. officinalis could easily be taken up by cancer cells as free fatty acids and had good potential as antitumor substances.

Antimicrobial Activity of Various Parts of Tomato Plants Varied with Different Solvent Extracts

The antimicrobial activity of acetone, hexane, dichloromethane, and methanol extracts from leaves, stems, immature green fruits, and red fruits of tomato plants was examined against six phytopathogens. The minimum inhibitory concentration (MIC) of the acetonic extracts from these four plant parts was lower than that of the other solvents. Among the acetonic extracts, tomato leaves had a lower MIC than the other tomato parts. The acetonic extract from tomato leaves was therefore selected as a source of antimicrobial substances. The acetonic extract from tomato leaves inhibited mycelial growth of Fusarium oxysporum f. sp. lycopersici, Glomerella cingulata, and Rhizoctonia solani. Mycelial growth of R. solani treated with acetone extract from leaves showed more susceptibility than the other phytopathogens. Using 0.31 mg/ml of the acetonic extract from leaves, mycelial growth of R. solani on days 1, 2, and 3 decreased by 50.0, 52.1, and 64.0%, respectively, compared with acetone solvent treatment. The antimicrobial compounds effective against R. solani were identified as linolenic acid and caffeic acid by bioautography and GC-MS. These two compounds were used to treat six phytopathogens to confirm their antimicrobial activities. Linolenic acid inhibited mycelial growth of R. solani, while caffeic acid showed only slight antimicrobial activity. Results indicated that we propose extracts from tomato leaves which included antimicrobial compounds may provide a new lead in the pursuit of new biological sources of agrochemical candidates.

Changes in Lipid Profiles of Dried Clams ( Mactra chinensis Philippi and Ruditapes philippinarum) during Accelerated Storage and Prediction of Shelf Life

To predict the shelf life through an Arrhenius model and evaluate the changes in lipid profiles, two types of dried clams were stored at 50 and 65 °C and collected periodically for analysis. The predicted shelf life values of the two dried clam samples were 530 ± 14 and 487 ± 24 h (24 °C), and the relative errors between the actual and predicted values were 5.7 and 6.8%, respectively. During accelerated storage, the peroxide value, p-anisidine value, thiobarbituric acid-reactive substances value, total oxidation value, acid value, and free fatty acid content all increased, while the levels of triacylglycerol, phosphatidylcholine, phosphatidylethanolamine, major glycerophospholipid molecular species, and polyunsaturated fatty acid (PUFA) decreased. Moreover, content of phospholipid containing PUFA decreased significantly than that of triacylglycerol containing PUFA. Results indicated that the Arrhenius model was suitable for the shelf life prediction of dried clams and accelerated storage caused loss in quality of dried clams in terms of lipids.

Extrinsic plasmalogens suppress neuronal apoptosis in mouse neuroblastoma Neuro-2A cells: importance of plasmalogen molecular species

Plasmalogen, especially those having 22:6, suppressed neuronal apoptosisviadeath receptor and mitochondrial pathways. These mechanisms of action of plasmalogen may be responsible for regulation of membrane functions and second messenger production.

Acyl-lipid metabolism

Acyl lipids in Arabidopsis and all other plants have a myriad of diverse functions. These include providing the core diffusion barrier of the membranes that separates cells and subcellular organelles. This function alone involves more than 10 membrane lipid classes, including the phospholipids, galactolipids, and sphingolipids, and within each class the variations in acyl chain composition expand the number of structures to several hundred possible molecular species. Acyl lipids in the form of triacylglycerol account for 35% of the weight of Arabidopsis seeds and represent their major form of carbon and energy storage. A layer of cutin and cuticular waxes that restricts the loss of water and provides protection from invasions by pathogens and other stresses covers the entire aerial surface of Arabidopsis. Similar functions are provided by suberin and its associated waxes that are localized in roots, seed coats, and abscission zones and are produced in response to wounding. This chapter focuses on the metabolic pathways that are associated with the biosynthesis and degradation of the acyl lipids mentioned above. These pathways, enzymes, and genes are also presented in detail in an associated website (ARALIP: http://aralip.plantbiology.msu.edu/). Protocols and methods used for analysis of Arabidopsis lipids are provided. Finally, a detailed summary of the composition of Arabidopsis lipids is provided in three figures and 15 tables.

Studies on the lipids of sheep red blood cells. II. The incorporation of phosphorus into phospholipids of HK and LK cells

The incorporation of inorganic phosphate (as NaH(2)PO(4)) into the phospholipids of sheep red blood cells was studied in vitro in blood samples from five highpotassium (HK) and five low-potassium (LK) sheep. The erythrocytes from HK sheep incorporated more activity in 4 hr than those from the LK sheep. However no activity was incorporated into the major phospholipids of the cells (phosphatidyl ethanolamine, phosphatidyl serine, and sphingomyelin) of either group. The phosphatidic acid fraction was labeled in both groups and to a significantly greater extent in the HK samples. However the highest activity in the phospholipid of sheep red-cells was located in three unknown compounds not previously detected. Their specific activities were the same in the HK and the LK samples although they were present in slightly larger amounts in the HK samples. In general, incorporation was at a rather low level, and from stoichiometric considerations it was concluded that the metabolism in the red-cell phospholipids could not be directly involved in the active transport of ions across the cell membrane. This work also confirmed a previous report that no quantitative differences exist among the major phospholipid classes in the two types of cells.

Acyl-lipid metabolism

Acyl lipids in Arabidopsis and all other plants have a myriad of diverse functions. These include providing the core diffusion barrier of the membranes that separates cells and subcellular organelles. This function alone involves more than 10 membrane lipid classes, including the phospholipids, galactolipids, and sphingolipids, and within each class the variations in acyl chain composition expand the number of structures to several hundred possible molecular species. Acyl lipids in the form of triacylglycerol account for 35% of the weight of Arabidopsis seeds and represent their major form of carbon and energy storage. A layer of cutin and cuticular waxes that restricts the loss of water and provides protection from invasions by pathogens and other stresses covers the entire aerial surface of Arabidopsis. Similar functions are provided by suberin and its associated waxes that are localized in roots, seed coats, and abscission zones and are produced in response to wounding. This chapter focuses on the metabolic pathways that are associated with the biosynthesis and degradation of the acyl lipids mentioned above. These pathways, enzymes, and genes are also presented in detail in an associated website (ARALIP: http://aralip.plantbiology.msu.edu/). Protocols and methods used for analysis of Arabidopsis lipids are provided. Finally, a detailed summary of the composition of Arabidopsis lipids is provided in three figures and 15 tables.

Oil Characteristics and Nutritional Composition of the Ridge Gourd (Luffa acutangula Roxb.) Seeds Grown in Bangladesh

The aim of the work was a comparative study of oil characteristics and nutritional composition of seeds of two local varieties of ridge gourd collected from different districts of Bangladesh: Prince ridge gourd (PRG) and Hercules ridge gourd (HRG). Most of the physicochemical characteristics reported herein, of the seed oils of both varieties were significantly (p < 0.05) affected by sampling locations. Acylglycerol classes were estimated to be monoacylglycerols (1.6-1.9% in PRG and 1.4-1.6% in HRG), diacylglycerols (4.0-4.6% in PRG and 2.6-3.0% in HRG) and triacylglycerols (84.6-86.7% in PRG and 86.7-88.3% in HRG) whereas lipid classes to be neutral lipids (92.5-94.2% in PRG and 91.7-94.9% in HRG), glycolipids (2.8-3.2% in PRG and 2.5-3.9% in HRG) and phospholipids (1.9-2.4% in PRG and 1.2-2.6% in HRG). Glyceride and lipid compositions of PRG seed oil did not show any significant difference (p < 0.05) between the two samples of Rajshahi and Dinajpur districts. HRG samples had similar values for diacylglycerol contents. GLC analysis showed the presence of only four fatty acids from series C16:0 to C18:2. Linoleic acid was the major ranging from 49.5% to 51.0% in PRG and 48.6% to 49.2% in HRG. Both varieties contained considerable amounts of lipid (26.8-28.2% in PRG and 23.2-25.4% in HRG), protein (20.8-23.1% in PRG and 25.9-26.8% in HRG) and other essential nutrients. Most of the nutrient contents in PRG samples differed significantly (p < 0.05) than those found in HRG samples. Nutrient information reported herein illustrates the benefits to public health for those, who consume this plant fruit.

Lipid and fatty acid composition of mesocarp and seed of avocado fruits harvested at northern range in Japan

The lipid and fatty acid composition of the mesocarp and seed of avocado fruit grown and harvested in Japan, which is located at the northern range of the avacado, was investigated and compared to an imported avocado purchased commercially. The potential of the avocado mesocarp as an agricultural product in Japan was also explored. Total lipids (TL) accounted for approximately 20% of the mesocarp. Further analysis showed that the neutral lipid (NL) fraction accounted for at least 95% of the TL, and almost 90% of NL was triacylglycerol. Monoenoic acids accounted for at least 65% of the total fatty acids, and oleic acid, which is regarded as an especially important functional component of avacado accounted for approximately 50% of the monounsaturated fatty acids. A comparison of the Japanese avocado cultivars and an imported avocado cultivar in the present study revealed no significant differences in the lipid and fatty acid compositions. Therefore, production of avocado fruit, which is rich in various nutritional components, is expected to be increased on a larger number of farms in Japan in the future. It is believed to be necessary to carry out further verification, such as the establishment of a cultivation technique adoptable to Japan, examination of optimal soil and land features, and cultivar selection.

Enhanced solvent extraction of polar lipids associated with rubber particles from Hevea brasiliensis

Biochemical studies of lipids bound to rubber particles have been complicated due to the solubility of polyisoprene chains in most extracting solvents and the rather delicate nature of polar lipids that are often denatured when traditional solvent extraction techniques are employed. In this paper, we describe a traditional technique and accompanying solvents that permit optimal extraction of rubber particle bound lipids. The technique, which is validated after characterizing the lipid extracts by elemental analysis, silica column adsorption and thin layer chromatography, appeared more suitable for extracting total lipids with optimal glycolipid and phospholipid contents. This technique is proposed as an alternative to traditional extraction methods used for solid natural rubber as it offers advantages with respect to ease of application, extract quality, extraction yields and reproducibility.

Production of silkworms with conjugated linoleic acid (CLA) incorporated into their lipids by dietary CLA

Silkworms with conjugated linoleic acid (CLA) incorporated into their lipids (designated CLA silkworms) were produced to enhance the quality of silkworms having a synergistic effect with CLA functions by dietary synthetic CLA. Silkworm larvae were fed fresh mulberry leaves (control diet) until the third instar stage and were then subjected to various levels (0%, 0.1%, 1%, 5%, and 10%) of CLA-sprayed mulberry leaves (designated CLA diet) beginning on the first day of the fourth instar stage and continuing to the third day of the fifth instar stage. CLA contents in CLA silkworms increased proportionally with increasing CLA levels of CLA diets. CLA silkworms on a 1% CLA diet contained 2.2 g CLA/100 g lipid without body weight reduction, whereas CLA silkworms on a 10% CLA diet contained 14.8 g CLA/100 g lipid with a significant reduction of body weight, relative to the control silkworms. The CLA content in the lipids of CLA silkworms on a 10% CLA diet was significantly higher than that of CLA silkworms on a 5% CLA diet. A 0.1% CLA diet was not sufficient to accumulate CLA in the silkworms. Most of the CLA (approximately 99%) of silkworm lipids was present in triglyceride (TG) with a similar ratio of c9,t11 and t10,c12 CLA isomers. These results suggest that a 1% CLA diet was suitable for the production of CLA silkworms.

Wound-Induced Metabolism in Potato (Solanum tuberosum) Tubers: Biosynthesis of Aliphatic Domain Monomers

Suberin, a cell specific, wall-associated biopolymer, is formed during normal plant growth and development as well as in response to stress conditions such as wounding. It is characterized by the deposition of both a poly(phenolic) domain (SPPD) in the cell wall and a poly(aliphatic) domain (SPAD) thought to be deposited between the cell wall and plasma membrane. Although the monomeric components that comprise the SPPD and SPAD are well known, the biosynthesis and deposition of suberin is poorly understood. Using wound healing potato tubers as a model system, we have tracked the flux of carbon into the aliphatic monomers of the SPAD in a time course fashion. From these analyses, we demonstrate that newly formed fatty acids undergo one of two main metabolic fates during wound-induced suberization: (1) desaturation followed by oxidation to form the 18:1 omega-hydroxy and dioic acids characteristic of potato suberin, and (2) elongation to very long chain fatty acids (C20 to C28), associated with reduction to 1-alkanols, decarboxylation to n-alkanes and minor amounts of hydroxylation. The partitioning of carbon between these two metabolic fates illustrates metabolic regulation during wound healing, and provides insight into the organization of fatty acid metabolism.

Radical scavenging activity of black cumin (Nigella sativa L.), coriander (Coriandrum sativum L.), and niger (Guizotia abyssinica Cass.) crude seed oils and oil fractions

Crude vegetable oils are usually oxidatively more stable than the corresponding refined oils. Tocopherols, phospholipids (PL), phytosterols, and phenols are the most important natural antioxidants in crude oils. Processing of vegetable oils, moreover, could induce the formation of antioxidants. Black cumin (Nigella sativa L.), coriander (Coriandrum sativum L.), and niger (Guizotia abyssinica Cass.) crude seed oils were extracted with n-hexane and the oils were further fractionated into neutral lipids (NL), glycolipids (GL), and PL. Crude oils and their fractions were investigated for their radical scavenging activity (RSA) toward the stable galvinoxyl radical by electron spin resonance (ESR) spectrometry and toward 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical by spectrophotometric method. Coriander seed oil and its fractions exhibited the strongest RSA compared to black cumin and niger seed oils. The data correlated well with the total content of polyunsaturated fatty acids, unsaponifiables, and PL, as well as the initial peroxide values of crude oils. In overall ranking, RSA of oil fractions showed similar patterns wherein the PL exhibited greater activity to scavenge both free radicals followed by GL and NL, respectively. The positive relationship observed between the RSA of crude oils and their color intensity suggests the Maillard reaction products may have contributed to the RSA of seed oils and their polar fractions. The results demonstrate the importance of minor components in crude seed oils on their oxidative stability, which will reflect on their food value and shelf life. As part of the effort to assess the potential of these seed oils, the information is also of importance in processing and utilizing the crude oils and their byproducts.

Influence of emulsifying component composition on creams formulated with fractionated milkfat

Dairy systems formulated with fractionated milkfat and milk-derived components have compositional differences that may affect functionality and nutritional aspects as compared to natural dairy products. The composition of 20% milkfat creams formulated with emulsifying components (skim milk, sweet buttermilk, and butter-derived aqueous phase) and low- or medium-melt fractionated butteroil was compared with natural cream. Cream separation temperatures (49 and 55 degrees C) and processing conditions (commercial and pilot plant) in obtaining emulsifying components were examined for effect on content of surface active agents. Individual fatty acids, lipids, cholesterol, phospholipids, protein levels, and types varied with components. Separation temperature influenced the cholesterol level in the aqueous phase. A commercially produced aqueous phase contained less total lipid, protein, cholesterol, and phospholipid than aqueous phase obtained in the pilot plant. Milkfat globule membrane concentration of emulsifying components affected phospholipid and cholesterol content of formulated creams. Butteroil type affected cholesterol levels and cream formulations.

Possible role of ginsenoside Rb1 on regulation of rat liver triglycerides

We have studied the effects of ginsenoside Rb1 (GRb1) on the change in lipid contents in rat liver. When GRb1 was administered intraperitoneally to rats, liver microsomal cytochrome P-450 content and NADPH-cytochrome P-450 reductase activity were lower than those in control rats. The contents of triglyceride (TG) and cholesterol were decreased, but those of total phospholipid, phosphatidylcholine, and phosphatidylethanolamine were increased in the GRb1-treated group compared with controls. These results indicate that GRb1 might be involved in lipid metabolism by regulating the activity of microsomal cytochrome P-450 monooxygenase. Although liver TG levels were reduced by GRb1, the levels of TG and beta-lipoprotein in serum from the GRb1-treated group did not change as compared with those in controls. Thus we suggest that the decrease in liver TG levels with GRb1-treatment is not associated with the secretion of TG-rich very low-density lipoprotein. Furthermore, the level of cAMP was also significantly increased in the GRb1-treated group as compared with that in controls. Additionally, the cAMP level was more markedly increased as compared with that in the GRb1-treated group or control group when GRb, was exogenously added to the reaction system for measuring cAMP production in homogenates from control group liver. Accordingly, these results demonstrate that GRb1 might lower TG levels via cAMP-production in the liver, and GRb1 might be an interesting candidate to for a modulator of cAMP-mediated effects, especially within the liver steatosis system.

Characterization of galactosyl glycerolipids in the HT29 human colon carcinoma cell line

Glycoglycerolipids constitute a family of glycolipids with apparently very restricted expression in human tissues. They have previously been detected only in the testis and the nervous system. In the present study, two glycoglycerolipids were isolated from the HT29 human colon carcinoma cell line. The glycoglycerolipids were structurally characterized as a monogalactosylglycerolipid (1-O-alkyl-2-O-acyl-3-O-(beta-galactosyl)-sn-glycerol) and a digalactosylglycerolipid (1-O-alkyl-2-O-acyl-3-O-(beta-galactosyl(1-4)alpha-galactosyl)-sn-glycerol) using NMR and mass spectrometry. This digalactosylglycerolipid has not previously been structurally characterized. When HT29 cells were allowed to differentiate into more enterocyte-like cells by culture in glucose-free medium, expression of both of these glycoglycerolipids was greatly diminished. The presence of glycoglycerolipids in a human colon carcinoma cell line indicates that expression of this family of glycolipids may not be as restricted as previously thought. Instead this class of glycolipids may serve as differentiation antigens in various normal tissues and in tumor development. The Galalpha1-4Gal epitope was previously identified as a receptor for bacterial adhesins and toxins. The finding that this epitope is also linked to a glycerolipid moiety opens up new possible roles for this carbohydrate receptor in intracellular signaling.

Haemolytic glycoglycerolipids from Gymnodinium species

Glycoglycerolipids derived from microalgae can be a source of biologically active substances including toxins. Such glycolipids were analysed in two isolates of toxic marine dinoflagellates from European waters. The lipids of Gymnodinium mikimotoi contained 17% of monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG), while in Gymnodinium sp. the proportion was 35%. MGDG and DGDG from both species were haemolytic. The major unsaturated fatty acid in both algal glycolipids was 18:5 omega 3.

Membrane lipid perturbation modifies the set point of the temperature of heat shock response in yeast

Addition of a saturated fatty acid (SFA) induced a strong increase in heat shock (HS) mRNA transcription when cells were heat-shocked at 37 degrees C, whereas treatment with an unsaturated fatty acid (UFA) reduced or eliminated the level of HS gene transcription at 37 degrees C. Transcription of the delta 9-desaturase gene (Ole1) of Histoplasma capsulatum, whose gene product is responsible for the synthesis of UFA, is up-regulated in a temperature-sensitive strain. We show that when the L8-14C mutant of Saccharomyces cerevisiae, which has a disrupted Ole1 gene, is complemented with its own Ole1 coding region under control of its own promoter or Ole1 promoters of H. capsulatum, the level of HS gene transcription depends on the activity of the promoters. Fluorescence anisotropy of mitochondrial membranes of completed strains corresponded to the different activity of the Ole1 promoter used. We propose that the SFA/UFA ratio and perturbation of membrane lipoprotein complexes are involved in the perception of rapid temperature changes and under HS conditions disturbance of the preexisting membrane physical state causes transduction of a signal that induces transcription of HS genes.

Preparation and characterization of glucosylated aminoglycerophospholipids

Natural aminophospholipids were isolated from egg yolk and from human red blood cells. Glucosylated ethanolamine and serine phosphatides were prepared by exposing synthetic and natural aminophospholipids to glucose for 3-18 h at pH 7.4. The glucosylation products were resolved from parent phospholipids by normal-phase high-performance liquid chromatography and were identified by on-line mass spectrometry with an electrospray interface. The soft ionization method allowed us to detect the glucosylation products as molecular ions of the Schiff bases. The Schiff bases could be stabilized by sodium cyanoborohydride reduction. The molecular species of the ethanolamine and serine phosphatides reacted in proportion to their molar concentration in the mixtures. The yields of the glucosylation products varied with time of reaction and the concentration of glucose in the medium. At 50 mM glucose and 0.6 mg/mL phosphatidylethanolamine, 20% of the aminophospholipid was glycated in 18 h at 37 degrees C.

Quantitative chromatographic analysis of inositol phospholipids and related compounds

The metabolism of phospholipids and the mobilization of second messengers such as inositol-1,4,5-trisphosphate, 1,2-diacylglycerol (DAG) and arachidonic acid (AA) from phospholipids is commonly studied by radiolabelling phospholipids with [3H]myo-inositol or [32P]ATP and measuring the incorporation of radioactivity in different phospholipids or their hydrolysis products. However, for the radiolabelling method to accurately reflect changes in the compound's mass, it is essential that the tissue is labelled to isotopic equilibrium which is difficult to achieve. To circumvent the disadvantages of the radiolabelling method, several analytical procedures have been developed for the mass analysis of phospholipids and inositolphosphates (IPs). Quantitation of the mass or the radiolabelling of phospholipids is a complex multi-step procedure that involves quantitative isolation of phospholipids, fractionation of individual phospholipids and either determination of radioactivity in each component or the measurement of their mass. Phospholipids, DAG and AA are extracted from tissue sample with organic solvents such as chloroform-methanol (2:1) containing HCl or formic acid. The extract is separated by TLC, cartridge-column chromatography or HPLC on a reversed-phase column. Phospholipids are quantitated by measuring inorganic phosphate, absorption at 200 nm or mass spectrometry. Inositol phosphates are extracted with perchloric acid or trichloroacetic acid and separated by ion-exchange cartridge-column or HPLC with an ion-exchange column. IPs are quantitated by measuring inorganic phosphate or by using enzymatic reaction, metal-dye coupling, NMR or mass spectrometry.

Detection and time-course analysis of phospholipid hydroperoxide in soybean seedlings after treatment with fungal elicitor, by chemiluminescence-HPLC assay

Direct evidence for the existence of phosphatidylcholine hydroperoxide (PCOOH) and the determination of the changes in PCOOH after treatment of soybean seedlings with fungal elicitor, were examined using chemiluminescence-HPLC of hydroperoxide specific assay. PCOOH was transiently accumulated within 6 h after elicitor treatment but such an event was not observed in control plants, thus suggesting that accumulation of PCOOH was a response to fungal elicitor in the host plant. The result suggested that singlet oxygen had participated in the lipid hydroperoxidation, since non-conjugated fatty acid hydroperoxide isomers due to the singlet oxygen oxidation were detected in the phospholipid fraction. The reaction of lipid hydroperoxidation, preceding the induction of a defense compound, may be involved in the triggering of a plant defense mechanism against fungal invasion.