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PubMed1999

Phytosterol metabolism and absorption in the generalist grasshopper, Schistocerca americana (Orthoptera: Acrididae).

A series of experiments, using GLC, RP-HPLC, and GC-MS techniques, were performed to examine the metabolic fate and absorption of different dietary sterols in the grasshopper Schistocerca americana. In the first experiment, grasshoppers were reared on diets containing different sterols presented singly. Cholesterol was the dominant tissue sterol recovered from cholesterol and "soybean sitosterol" fed grasshoppers but among the grasshoppers fed diets with stigmasterol and spinach sterols (both unsuitable for growth and development), the amount of cholesterol recovered was not different from that of newly hatched grasshoppers. In the second experiment, grasshoppers were given diets containing mixtures of soybean sitosterol and stigmasterol and the metabolic fate of these dietary sterols was recorded. Results from this experiment suggest that the presence of an unsuitable dietary sterol does not interfere with cholesterol production from sitosterol. They also demonstrate that large quantities of unmetabolized dietary sterols with C-24 ethyl groups are recovered from grasshoppers fed diets containing stigmasterol. Finally, tissue sterol profiles of grasshoppers with and without their midguts were compared. Results suggest that the midgut is the major tissue where unmetabolized dietary sterols accumulate. How these sterol metabolic constraints impact development and survival is discussed as well as the impact they might have on grasshopper feeding behavior. Arch.

Absorption↗
PubMed2005

Separation of phytosterol oxidation products by combination of different polarity gas chromatography capillary columns.

The number of characterized phytosterol oxidation products (POPs) from both ring- and side-chain structures has increased during recent decades, resulting in difficulties in the separation of POPs on different gas chromatography (GC) capillary columns. The main objective of this study was to separate a mixture of 29 purified and characterized oxidation products from sito-, campe- and stigmasterol using GC capillary columns with different polarity. For the first time in the area of POPs analysis, the separation efficiency of the combination of two capillary GC columns with different polarities was investigated. A non-polar 5% phenyl coated (DB5-MS) and a mid-polar 35% phenyl coated (DB35-MS) column was combined with a pressfit connector. The main improvement was enhanced base line separation for many of the analyzed POPs, compared with the separations achieved using the individual columns. However, three pairs of POPs co-eluted: 24-hydroxysitosterol/campesterol-5beta,6beta-epoxide, stigmasterol-5beta,6beta-epoxide/campesterol-5alpha,6alpha-epoxide and stigmasterol-5alpha,6alpha-epoxide/campestanetriol.

Chromatography, Gas↗
PubMed2005

Quantitative determination of cholesterol, sitosterol, and sitostanol in cultured Caco-2 cells by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

In this study, we describe a simple liquid extraction (methanol/choloroform, 1:1, v/v) method for endogenous free cholesterol and administered sterols extracted from cultured Caco-2 cells. To quantify sterol contents in Caco-2 cells, a new HPLC-APCI-MS method was developed. All the sterols were baseline separated using reversed-phase column (C8, 2.1 mm x 150 mm, 3.5 microm) and isocratic conditions (90%, v/v, methanol-water mixture containing 0.2 mM ammonium acetate). The full scan mass spectra of sterols were measured by an ion trap mass spectrometer equipped with an APCI ion source. The intense fragment ions resulting from the loss of water [M+H-H2O]+ (m/z 369, 395, 397 and 399 for cholesterol, stigmasterol, sitosterol, and sitostanol, respectively) were used for determinations. The absolute extraction recovery of sterols from the spiked cell samples were 109.7+/-26.2, 105.7+/-5.1, 109.8+/-5.0 and 99.0+/-7.0% for cholesterol, stigmasterol, sitosterol, and sitostanol, respectively. Furthermore, no significant matrix effect was observed for the sterols in the cell samples. The sample assay was based on the internal standard method using stigmasterol as an internal standard. The method was linear over the concentration ranges of 0.45-9.0 microM (cholesterol) and 0.225-7.2 microM (sitosterol and sitostanol). The within- and between-day precision was less than 7% and accuracy ranged from 93.51 to 101.77%. The lowest limit of quantitation (LLOQ) was 0.225 microM for sitosterol and sitostanol, and 0.45 microM for cholesterol. The accuracy range was 95-106% and precision was lower than 9% for all LLOQ values.

Caco-2 Cells↗
PubMed1999

Optimisation of plant sterols incorporation in human keratinocyte plasma membrane and modulation of membrane fluidity.

The in vitro effects of plant sterols were investigated with regard to their uptake and membrane lipid fluidity in human keratinocytes. Among the different media tested to transport sterols (liposomes, micelles and organic solvents), the best results in terms of incorporation and viability were obtained by the use of the organic solvents dimethylsulfoxide and ethanol. After 48 h incubation exogenous sterol can account for about 30% of the total cell sterol content. The total sterol amount in plasma membranes increased 2-fold after incubation with cholesterol, whereas it was not altered when phytosterols were incorporated. The incorporation of cholesterol, sitosterol and stigmasterol led to an increase in the percent of unsaturated fatty acid C18:1 in the plasma membrane. The effect of this uptake on membrane fluidity was studied by means of fluorescence polarisation using DPH and TMA-DPH as fluorescent probes. Whereas cholesterol and sitosterol had no significant effect on the DPH fluorescence anisotropy (rs), the presence of stigmasterol induced a 12% decrease of rs reflecting an increase in membrane fluidity. We can conclude from this study that in the presence of sitosterol, the mean fluidity of the membrane is regulated whereas stigmasterol triggers a looseness of molecular packing of phospholipids acyl chains, in accordance with previous results obtained on purely lipid model membranes.

Cell Line↗
PubMed1999

Safety evaluation of phytosterol esters. Part 4. Faecal concentrations of bile acids and neutral sterols in healthy normolipidaemic volunteers consuming a controlled diet either with or without a phytosterol ester-enriched margarine.

A study was conducted in 12 healthy males and 12 females (mean age 36 years) to assess the impact of a margarine enriched with phytosterol esters on faecal concentrations of bile acids and sterols. During the run-in period, volunteers consumed 40 g of a control margarine for 21 consecutive days if male, and for 28 days if female. Half of the volunteers were then randomly allocated to consume the control margarine for another 21 or 28 days, respectively. The remaining subjects consumed 40 g of a margarine containing 8.6 g vegetable oil phytosterol (46% (w/w) beta-sitosterol, 26% campesterol, 20% stigmasterol). Throughout the total study subjects consumed the same diet adjusted for individual energy requirements. The phytosterol ester-enriched spread significantly enhanced faecal neutral sterol concentrations from about 40 mg/g to 190 mg/g dry weight faeces. Faecal neutral sterol metabolites increased from about 30 mg/g to about 50 mg/g. The major parent sterols excreted were cholesterol, sitosterol, campesterol and stigmasterol. Sitosterol, campesterol and stigmasterol comprised 28%, 15% and 12% of the total faecal neutral sterols, reflecting the composition of the sterol enriched margarine. The major sterol metabolites excreted were metabolites formed by, predominantly, oxidation at the 3-position and metabolites saturated at the 5,6 position in a beta-configuration. Faecal secondary bile acid concentration was reduced by vegetable oil sterols from 7.6 mg/g dry faeces to 6.0 mg/g. Consumption of vegetable oil phytosterols slightly but significantly increased the faecal concentration of 4-cholesten-3-one. However, 4-cholesten-3-one concentration remained very low (< 2 mg/g) and in line with values reported in the literature for subjects fed high or low fat diets. No sterol oxides could be detected in the faeces. We conclude that in healthy adult males and females a high intake of vegetable oil phytosterol esters does increase the amount of neutral sterols in the faeces, as expected, but does not result in the increased formation of bile acids or sterol metabolites.

Adult↗
PubMed1989

Lipid Composition of Plasma Membranes and Endomembranes Prepared from Roots of Barley (Hordeum vulgare L.) : Effects of Salt.

Membrane fractions enriched in endoplasmic reticulum (ER), tonoplast and Golgi membranes (TG) and plasma membranes (PM) were prepared from barley (Hordeum vulgare L. cv CM 72) roots and the lipid compositions of the three fractions were analyzed and compared. Plants were grown in an aerated nutrient solution with or without 100 millimolar NaCl. Each membrane fraction had a characteristic lipid composition. The mole per cent of the individual phospholipids, glycolipids, and sterols in each fraction was not altered when roots were grown in 100 millimolar NaCl. The ER had the highest percentages of phosphatidylinositol and phosphatidylcholine of the three fractions (7 and 45 mole per cent, respectively, of the total lipid). The TG contained the highest percentage of glycosylceramide (13 mole per cent). The PM had the highest percentage of phosphatidylserine (3 mole per cent) and nearly equal percentages of phosphatidylethanolamine (15 mole per cent and phosphatidylcholine (18 mole per cent). The most abundant sterols in membranes prepared from barley roots were stigmasterol (10 mole per cent), sitosterol (50 mole per cent), and 24zeta-methylcholesterol (40 mole per cent of the total sterol). Salt-treated plants contained a slightly higher percentage of stigmasterol than controls. The percentage of stigmasterol increased with age and a simple cause and effect relationship between salt treatment and sterol composition was not observed.

Journal Article↗
PubMed1974

Beta-sitosterolemia and xanthomatosis. A newly described lipid storage disease in two sisters.

Although the usual diet may contain 150-250 mg of plant sterols, chiefly beta-sitosterol, only trace amounts of these sterols have heretofore been found in human or animal blood and tissues. We now report elevated plant sterol levels in the blood and tissues of two sisters with extensive tendon xanthomas but normal plasma cholesterol levels. Besides beta-sitosterolemia and xanthomatosis, no other physical, mental, or biochemical abnormalities were detected.Repeatedly, the plasmas of the two sisters have contained 27.1 and 17.7 mg/100 ml of beta-sitosterol, 9.7 and 8.2 mg/100 ml of campesterol, and 0.5 and 0.5 mg/100 ml of stigmasterol, respectively. These plant sterols constituted 15.6 and 11.3% of the total plasma sterols. Some 60% of the plasma beta-sitosterol and campesterol was esterified; the measurable stigmasterol was entirely unesterified. The transport of the plasma beta-sitosterol and campesterol was largely in low density lipoproteins (76 and 83%, respectively). High density lipoproteins carried the remainder. Plant sterols were barely detectable in the very low density lipoprotein fraction. Only trace amounts of stigmasterol could be detected in the low density and high density lipoprotein fractions. The plant sterol content of the red blood cells averaged 12-13 mg/100 ml packed cells or about 13% of the total sterols. Two tendon xanthoma biopsies with the usual high concentration of cholesterol had 36.7 and 4.0 mg of plant sterols/g dry wt, of which 25.7 and 2.9 mg were beta-sitosterol, entirely in the free form. Plant sterols were also found in adipose tissue (0.2 mg/g wet wt) and in skin surface lipids (3.2 mg/g of lipid). The intestinal absorption of beta-sitosterol in both the patients, measured by two techniques, indicated greatly increased absorption of this sterol (about 24 and 28% in the patients L. H. and R. H., respectively, normal absorption being <5%). We suggest that increased absorption of beta-sitosterol must be considered as one cause of this disease. The reason for the extensive xanthomatosis in these two patients remains unknown. Perhaps in some way plant sterols initiated the development of xanthomas with otherwise normal plasma cholesterol levels. Clinical atherosclerosis has not yet occurred. The occurrence of beta-sitosterolemia in these two sisters with un-affected parents suggests an inherited recessive trait.

Adipose Tissue↗
PubMed2026

Elucidating the Mechanism of Xiaoqinglong Decoction in Chronic Urticaria Treatment: An Integrated Approach of Network Pharmacology, Bioinformatics Analysis, Molecular Docking, and Molecular Dynamics Simulations.

INTRODUCTION: Xiaoqinglong Decoction (XQLD) is a traditional Chinese medicinal formula commonly used to treat chronic urticaria (CU). However, its underlying therapeutic mechanisms remain incompletely characterized. This study employed an integrated approach combining network pharmacology, bioinformatics, molecular docking, and molecular dynamics simulations to identify the active components, potential targets, and related signaling pathways involved in XQLD's therapeutic action against CU, thereby providing a mechanistic foundation for its clinical application. METHODS: The active components of XQLD and their corresponding targets were identified using the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. CU-related targets were retrieved from the OMIM and GeneCards databases. Subsequently, core components and targets were determined via protein-protein interaction (PPI) network analysis and component-target-pathway network construction. Topological analyses were performed using Cytoscape software to prioritize core nodes within these networks. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted via the DAVID database to identify enriched biological processes and signaling pathways. Molecular docking was performed to evaluate binding interactions between key components and core targets, while molecular dynamics (MD) simulations were employed to assess the stability of the component-target complexes with the lowest binding energy. Finally, CU-related targets of XQLD were validated using datasets from the Gene Expression Omnibus (GEO) database. RESULTS: A total of 135 active components and 249 potential targets of XQLD were identified, alongside 1,711 CU-related targets. Core components, such as quercetin, kaempferol, beta-sitosterol, naringenin, stigmasterol, and luteolin, exhibited high degree values in the constructed networks. The core targets identified included AKT1, TNF, IL6, TP53, PTGS2, CASP3, BCL2, ESR1, PPARG, and MAPK3. GO and KEGG pathway enrichment analyses revealed the PI3K-Akt signaling pathway as a central regulatory mechanism. Molecular docking studies demonstrated strong binding affinities between active components and core targets, with the stigmasterol-AKT1 complex exhibiting the lowest binding energy (-11.4 kcal/mol) and high stability in MD simulations. Validation using GEO datasets identified 12 core genes shared between CU-related targets and XQLD-associated targets, including PTGS2 and IL6, which were also prioritized as core targets in the network pharmacology analyses. DISCUSSION: This study comprehensively integrates multidisciplinary approaches to clarify the potential molecular mechanisms of XQLD in treating CU, highlighting its multitarget and multipathway synergistic effects. Molecular docking and dynamics simulations confirm the stable interaction between stigmasterol and the core target AKT1. Additionally, GEO dataset analysis verifies the pathogenic relevance of targets such as PTGS2 and IL6, significantly enhancing the credibility of our findings. These results provide a modern scientific basis for the traditional therapeutic effects of XQLD on CU and have important implications for developing multitarget treatments for this condition. However, this study mainly relies on database mining and computational simulations. Further in vitro and in vivo experimental validations are needed to confirm the predicted component-target-pathway interactions. CONCLUSION: This study identifies the active components, potential targets, and pathways through which XQLD exerts therapeutic effects on CU. These findings provide a theoretical foundation for further mechanistic studies and support their clinical application in the treatment of CU.

Molecular Docking Simulation↗
PubMedDate not supplied

[Effect of drought on the content of polar lipids and sterols in wheat leaves].

Composition of lipids and sterols in leaf tissues of winter wheat varieties with different drought resistance was investigated under the heat and water deficit. The data obtained have shown that the water deficit induced accumulation of sulpholipids and sitosterol accompanied by a decrease of stigmasterol in resistant plants. A decrease of monogalactosyldiacylglycerol, sulpholipid, phosphatidyl choline and sitosterol was observed against an increase of the stigmasterol content in the sensitive plants. The action of high temperature induced accumulation of sulpholipid, phosphatidyl glycerol, sitosterol and cholesterol accompanied by a decrease of campasterol and stigmasterol in a resistant variety. A sensitive variety was characterized by a decrease of sulpholipid and sitosterol.

Cholesterol↗
PubMed1998

Involvement of the mevalonic acid pathway and the glyceraldehyde-pyruvate pathway in terpenoid biosynthesis of the liverworts Ricciocarpos natans and Conocephalum conicum.

The incorporation of 13C-labeled glucose into borneol, bornyl acetate, the sesquiterpenes cubebanol and ricciocarpin A, phytol, and stigmasterol has been studied in axenic cultures of the liverworts Ricciocarpos natans and Conocephalum conicum. Quantitative 13C NMR spectroscopic analysis of the resulting labeling patterns showed that the isoprene building blocks of the sesquiterpenes and stigmasterol are built up via the mevalonic acid pathway, whereas the isoprene units of the monoterpenes and the diterpene phytol are exclusively derived from the glyceraldehyde-pyruvate pathway. These results indicate the involvement of both isopentenyl diphosphate biosynthetic pathways in different cellular compartments.

Camphanes↗
PubMed1975

Unique pathways of sterol metabolism in the Mexican bean beetle, a plant-feeding insect.

Radiolabeled sterols, 14C-cholesterol, 14C-cholestanol, 3H-stigmasterol, 3H-stigmastanol, and 3H-sitosterol, were fed to larvae of the Mexican bean beetle, Epilachna varivestis Mulsant, bu coating soybean leaves. Free sterol and sterol ester fractions from treated insects were isolated and analyzed, and in each case nearly 30% or more of total radiolabeled sterols retained by the insect were found in the sterol ester fraction after 8 days. delta5-Dietary sterols were readily reduced to stanols, and C29-stanols thus produced were dealkylated to cholestanol. Significant amounts of labeled lathosterol were formed from delta5-C29 sterols; little, if any, radiolabeled cholesterol was detected in insects fed either of the labeled delta5-phytosterols, stigmasterol or sitosterol. Sterol metabolism of this insect thus differs considerably from that found for most phytophagous insects.

Animals↗
PubMed1975

Dealkylation of 24-ethylsterols by Tetrahymena pyriformis.

When Tetrahymena pyriformis was incubated with sitosterol ([24R]-24-ethylcholest-5-en-3 beta-ol]) or its trans-delta22-derivative (stigmasterol), the C-24-dealkylated product, cholesta-5,7,trans-22-trien-3 beta-ol, was obtained in both cases. 24(S)-24-Ethylcholesta-5,7,trans-22-trien-3 beta-ol also was found to be a metabolite. When sitosterol was the substrate, 24(R)-24-ethylcholesta-5,7-dien-3 beta-ol was obtained as a third product. Identifications were made by mass spectroscopy, quantitative chromatography, labeling with 14C, and by other means. The dealkylated product (cholestratrienol) represented 30 percent of the sterols isolable after incubation. The administration of sterols to this organism did not induce sterol biosynthesis, since 2-14C-mevalonate failed to yield radioactive sterol in the presence of added stigmasterol.

Animals↗
PubMed1995

Comparative studies of metabolism of 4-desmethyl, 4-monomethyl and 4,4-dimethyl sterols in Manduca sexta.

To investigate the metabolism and possible deleterious effects of 4-methyl and 4,4-dimethyl steroids in Manduca sexta, the 4,4-dimethyl sterols lanosterol and cycloartenol, the 4-methyl sterol obtusifoliol and the 4,4-dimethyl pentacyclic triterpenoid alpha-amyrin were fed in an artificial agar-based diet at various concentrations. Utilization and metabolism of these four compounds were compared with sitosterol, stigmasterol, brassicasterol, ergosterol and 24-methylenecholesterol, 24-alkyl sterols that are readily dealkylated and converted to cholesterol in Manduca and in most phytophagous insects. None of the 4-methylated compounds significantly inhibited development except at very high dietary concentrations. The delta 24-bonds of lanosterol and cycloartenol were effectively reduced by the Manduca delta 24-sterol reductase enzyme, as is the delta 24-bond of desmosterol which, in most phytophagous insects, is an intermediate in the conversion of sitosterol, stigmasterol and other C28 and C29 phytosterols to cholesterol. On the other hand, the 24-methylene substituent of obtusifoliol was not dealkylated. Each of the 4-desmethyl C28 and C29 sterols was readily converted to cholesterol, and a significant amount of 7-dehydrocholesterol was derived from ergosterol metabolism. The reason for the differences in substrate specificity of these sterols is not clear, but the information may be useful in the development of new, specific, mechanism-based inhibitors of sterol metabolism.

Animals↗
PubMed1988

Interaction of the polyene antibiotic filipin with model and natural membranes containing plant sterols.

The interaction of the polyene antibiotic, filipin, with individual or mixed plant sterols (stigmasterol, sitosterol, campesterol and 24-methylpollinastanol) incorporated into large unilamellar vesicles (LUV) of soybean phosphatidylcholine (PC) as well as the filipin interaction with purified membrane fractions from maize roots containing these sterols was investigated by ultraviolet (UV) absorption and and circular dichroism (CD) spectroscopy. With both types of membrane preparation, dramatic changes in the UV absorption and CD spectra of the antibiotic were evidenced. When LUV containing stigmasterol, sitosterol and/or campesterol were incubated with low filipin concentrations (i.e., for filipin/sterol molar ratios (rst) lower than 1), CD signal characteristic of the formation of filipin-sterol complexes were observed. At higher rst values, the filipin-sterol interaction was shown to be in competition with a filipin-phospholipid interaction. With 24-methylpollinastanol-containing LUV, the filipin-phospholipid interaction was detected even at rst values lower than 1, which suggests a lower affinity of filipin for this sterol and emphasizes the structural differences between delta 5-sterols and 9 beta,19-cyclopropylsterols. With sterol-free soybean PC LUV, a filipin-phospholipid interaction could also be evidenced. With maize root cell membranes containing either delta 5-sterols or 9 beta,19-cyclopropylsterols, CD spectra similar to those obtained in the presence of LUV having these sterols as components were observed. Thus, the protein component of the membranes does not appear to be an important feature.

Cell Membrane↗
PubMed1990

Effects of steroid molecules on the dynamical structure of dioleoylphosphatidylcholine and digalactosyldiacylglycerol bilayers.

The ESR spectra of cholestane spin labels (CSL) in dioleoylphosphatidylcholine (DOPC) bilayers containing 20 wt% of cholesterol, 7-dehydrocholesterol, beta-sitosterol, stigmasterol and lanosterol exhibit a marked similarity, thus indicating that these steroids induced the same effects on the lipid bilayer over the temperature range 21-55 degrees C. The incorporation of these steroids into the DOPC bilayers enhances the orientational order of the CSL molecules at every temperature studied, but only induces a pronounced slow-down in their rotational motions at temperatures above 35 degrees C. Similar results were obtained in DOPC/ergosterol multilamellar liposomes, but the changes are now less pronounced than in the other five DOPC/steroid systems. In contrast, the addition of stigmasterol to digalactosyldiacylglycerol (DGDG) bilayers appears to increase the order parameter mean value of P2, without affecting the diffusion coefficients. Furthermore, the incorporation of 7-dehydrocholesterol to DGDG bilayers causes a large enhancement in the orientational order, but has only a small effect on D perpendicular of the CSL molecules. Importantly, this latter effect appears to be independent of temperature. The marked changes in the rates of the rotational motion brought about by the addition of steroids, contrasts with the lack of a significant effect of unsaturation on the bilayer dynamics reported by us previously (Korstanje et al. (1989), Biochim. Biophys. Acta 980, 225-233, and 982, 196-204).

Chemical Phenomena↗
PubMed1979

Absorbability of plant sterols and their distribution in rabbit tissues.

Rabbits were fed a low cholesterol diet containing 2% plant sterols for 10 weeks to determine the absorbability of these sterols and their deposition in the tissues. We found campesterol and beta-sitosterol in the blood and tissues. The plasma campesterol levels were 4.34--13.3 mg/100 ml, whereas, beta-sitosterol levels were 0.41--1 mg/100 ml. Stigmasterol was not detected. The total plasma plant sterol concentration was about 10% of the total plasma sterol. The mean terminal plasma cholesterol concentration averaged 60% higher (55 vs. 88 mg/100 ml, P less than 0.001) than the mean initial value. Campesterol was the preponderant sterol in all tissues studied, including the aorta. Sitosterol was found in small amounts in the tissues of the abdominal organs. Stigmasterol was not detected in any tissue studied. Esterified campesterol and sitosterol were detected in trace amounts in most tissues. Campesterol and sitosterol, particularly the former, accumulated in the tissues including the aorta.

Animals↗
PubMed1987

Paclobutrazol inhibition of sterol biosynthesis in a cell suspension culture and evidence of an essential role for 24-ethylsterol in plant cell division.

Growth of a celery (Apium gravidens) cell suspension culture was inhibited by the synthetic plant growth regulator paclobutrazol. Paclobutrazol caused a reduction in the incorporation of [2-14C]acetate into the 4-demethyl sterols (campesterol, sitosterol, stigmasterol) but radioactivity accumulated in the 4 alpha-methylsterols. The accumulating 4 alpha-methylsterols were identified as obtusifoliol and cycloeucalenol indicating that paclobutrazol was inhibiting sterol biosynthesis by blocking 14 alpha-demethylation. The inhibition of celery cell growth by paclobutrazol could be partially overcome by addition of cholesterol to the culture medium. However, addition of stigmasterol restored growth to the control value suggesting an essential role for a 24-ethylsterol to support plant cell division.

Acetates↗
PubMed1988

Schistosoma mansoni: sterol and phospholipid composition of cercariae, schistosomula, and adults.

The sterol and phospholipid composition of cercariae, schistosomula, and adult Schistosoma mansoni was analyzed by gas-liquid chromatography and high-performance liquid chromatography (HPLC). Cercariae and schistosomula contained cholesterol, desmosterol, campesterol, stigmasterol, and beta-sitosterol while adults contained only cholesterol. In all stages cholesterol comprised greater than 50% of the total sterols, and in cercariae and schistosomula desmosterol comprised 38 and 21% of the total sterols, respectively. The other three sterols, campesterol, stigmasterol, and beta-sitosterol, made up approximately 10% of the total. The same five sterols found in cercariae and schistosomula were present in the hepatopancreas of uninfected snails but with a much higher desmosterol concentration in the parasite, 38%, than in the snail, 2%. As in cercariae and schistosomula the three minor sterols comprised approximately 10%. Thus, the sterol composition of cercariae and schistosomula was similar but not identical to that of the snail host. Phosphatidylcholine was the major phospholipid of all three stages (50%) as determined by two HPLC procedures. The remaining phospholipids consisted of phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol. In addition, in adults there were small quantities of sphingomyelin and lysophosphatidylcholine. The percentage of each phospholipid was similar among stages with the exception of a slight increase in phosphatidylserine in adults compared to cercariae and schistosomula. These results show that a characteristic lipid composition is found in cercariae, schistosomula, and adults.

Animals↗