WorldWideScience

Sample records for fluorescent sterol dehydroergosterol

  1. Free-cholesterol loading does not trigger phase separation of the fluorescent sterol dehydroergosterol in the plasma membrane of macrophages

    DEFF Research Database (Denmark)

    Wüstner, Daniel

    2008-01-01

    membrane distribution of the fluorescent cholesterol-mimicking sterol dehydroergosterol (DHE) was investigated in FC-loaded J774 macrophages. Wide field fluorescence and deconvolution microscopy were combined with quantitative assessment of sterol distribution in straightened plasma membrane image segments...... with increased membrane cholesterol content, sterols do not form a separate phase in the plasma membrane....

  2. The role of ABC proteins Aus1p and Pdr11p in the uptake of external sterols in yeast: dehydroergosterol fluorescence study

    DEFF Research Database (Denmark)

    Kohut, Peter; Wüstner, Daniel; Hronska, L;

    2011-01-01

    applied the fluorescent ergosterol analog dehydroergosterol (DHE) to monitor the initial steps of sterol uptake by three independent approaches: fluorescence spectroscopy, fluorescence microscopy and sterol quantification by HPLC. Using specific fluorescence characteristics of DHE we showed that the entry...... of sterol molecules into plasma membrane is not spontaneous but requires assistance of two ABC (ATP-binding cassette) pumps--Aus1p or Pdr11p. DHE taken up by uptake-competent hem1ΔAUS1PDR11 cells could be directly visualized by UV-sensitive wide field fluorescence microscopy. HPLC analysis of sterols...... revealed significant amounts of exogenous ergosterol and DHE (but not cholesterol) associated with uptake-deficient hem1Δaus1Δpdr11Δ cells. Fluorescent sterol associated with these cells did not show the characteristic emission spectrum of membrane-integrated DHE. The amount of cell-associated DHE...

  3. Selective visualization of fluorescent sterols in Caenorhabditis elegans by bleach-rate-based image segmentation

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Landt Larsen, Ane; Færgeman, Nils J.

    2010-01-01

    The nematode Caenorhabditis elegans is a genetically tractable model organism to investigate sterol transport. In vivo imaging of the fluorescent sterol, dehydroergosterol (DHE), is challenged by C. elegans' high autofluorescence in the same spectral region as emission of DHE. We present a method...... autofluorescence and compare our method with three-photon excitation microscopy of sterol in selected tissues. Bleach-rate-based UV-WF imaging is a useful tool for genetic screening experiments on sterol transport, as exemplified by RNA interference against the rme-2 gene coding for the yolk receptor and for worm...

  4. Quantitative assessment of sterol traffic in living cells by dual labeling with dehydroergosterol and BODIPY-cholesterol

    DEFF Research Database (Denmark)

    Wustner, D.; Solanko, L.; Sokol, Olena;

    2011-01-01

    and followed a stretched exponential decay, while the fluorescence lifetime of BCh2 was comparable in various cellular regions. Our results indicate that BCh2 is suitable for analyzing sterol uptake pathways and inter-organelle sterol flux in living cells. The BODIPY-moiety affects lipid phase preference...... simultaneous imaging of both sterols in model membranes and living cells. BCh2 had a lower affinity than DHE for the biologically relevant liquid-ordered phase in model membranes. Still, DHE and BCh2 trafficked from the plasma membrane to the endocytic recycling compartment (ERC) of BHK cells with identical...... kinetics. This transport pathway was strongly reduced after energy depletion of cells or expression of the dominant-negative clathrin heavy chain. The partitioning into lipid droplets of BHK and HeLa cells was higher for BCh2 than for DHE. Within droplets, the photodegradation of BCh2 was enhanced...

  5. Potential of ultraviolet widefield imaging and multiphoton microscopy for analysis of dehydroergosterol in cellular membranes

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Brewer, Jonathan R.; Bagatolli, Luis;

    2011-01-01

    Dehydroergosterol (DHE) is an intrinsically fluorescent sterol with absorption/emission in the ultraviolet (UV) region and biophysical properties similar to those of cholesterol. We compared the potential of UV-sensitive low-light-level wide-field (UV-WF) imaging with that of multiphoton (MP) exc...

  6. Spatiotemporal analysis of endocytosis and membrane distribution of fluorescent sterols in living cells

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Faergeman, Nils J

    2008-01-01

    Distribution and dynamics of cholesterol in the plasma membrane as well as internalization pathways for sterol from the cell surface are of great cell biological interest. Here, UV-sensitive wide field microscopy of the intrinsically fluorescent sterols, dehydroergosterol (DHE) and cholestatrienol...... (CTL) combined with advanced image analysis were used to study spatiotemporal sterol distribution in living macrophages, adipocytes and fibroblasts. Sterol endocytosis was directly visualized by time-lapse imaging and noise-robust tracking revealing confined motion of DHE containing vesicles in close...... proximity to the cell membrane. Spatial surface intensity patterns of DHE as well as that of the lipid marker DiIC12 being assessed by statistical image analysis persisted over several minutes in cells having a constant overall curvature. Sites of sterol endocytosis appeared indistinguishable from other...

  7. Chromatic aberration correction and deconvolution for UV sensitive imaging of fluorescent sterols in cytoplasmic lipid droplets

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Faergeman, Nils J

    2008-01-01

    Intrinsically fluorescent sterols, like dehydroergosterol (DHE), mimic cholesterol closely and are therefore suitable to determine cholesterol transport by fluorescence microscopy. Disadvantages of DHE are its low quantum yield, rapid bleaching, and the fact that its excitation and emission...... macrophage foam cells and in adipocytes. We used deconvolution microscopy and developed image segmentation techniques to assess the DHE content of lipid droplets in both cell types in an automated manner. Pulse-chase studies and colocalization analysis were performed to monitor the redistribution of DHE upon...

  8. Chromatic aberration correction and deconvolution for UV sensitive imaging of fluorescent sterols in cytoplasmic lipid droplets.

    Science.gov (United States)

    Wüstner, Daniel; Faergeman, Nils J

    2008-08-01

    Intrinsically fluorescent sterols, like dehydroergosterol (DHE), mimic cholesterol closely and are therefore suitable to determine cholesterol transport by fluorescence microscopy. Disadvantages of DHE are its low quantum yield, rapid bleaching, and the fact that its excitation and emission is in the UV region of the spectrum. Thus, one has to deal with chromatic aberration and low signal-to-noise ratio. We developed a method to correct for chromatic aberration between the UV channel and the red/green channel in multicolor imaging of DHE compared with the lipid droplet marker Nile Red in living macrophage foam cells and in adipocytes. We used deconvolution microscopy and developed image segmentation techniques to assess the DHE content of lipid droplets in both cell types in an automated manner. Pulse-chase studies and colocalization analysis were performed to monitor the redistribution of DHE upon adipocyte differentiation. DHE is targeted to transferrin-positive recycling endosomes in preadipocytes but associates with droplets in mature adipocytes. Only in adipocytes but not in foam cells fluorescent sterol was confined to the droplet-limiting membrane. We developed an approach to visualize and quantify sterol content of lipid droplets in living cells with potential for automated high content screening of cellular sterol transport.

  9. Potential of ultraviolet widefield imaging and multiphoton microscopy for analysis of dehydroergosterol in cellular membranes

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Brewer, Jonathan R.; Bagatolli, Luis

    2011-01-01

    Dehydroergosterol (DHE) is an intrinsically fluorescent sterol with absorption/emission in the ultraviolet (UV) region and biophysical properties similar to those of cholesterol. We compared the potential of UV-sensitive low-light-level wide-field (UV-WF) imaging with that of multiphoton (MP...... found that the lateral resolution of MP microscopy is ∼1.5-fold higher than that of UV-WF deconvolution microscopy, allowing for improved spatiotemporal analysis of plasma membrane sterol distribution. Surface intensity patterns of DHE with a diameter of 0.2 μm persisting over several minutes could...

  10. A fluorescence method to detect and quantitate sterol esterification by lecithin:cholesterol acyltransferase.

    Science.gov (United States)

    Homan, Reynold; Esmaeil, Nadia; Mendelsohn, Laurel; Kato, Gregory J

    2013-10-01

    We describe a simple but sensitive fluorescence method to accurately detect the esterification activity of lecithin:cholesterol acyltransferase (LCAT). The new assay protocol employs a convenient mix, incubate, and measure scheme. This is possible by using the fluorescent sterol dehydroergosterol (DHE) in place of cholesterol as the LCAT substrate. The assay method is further enhanced by incorporation of an amphiphilic peptide in place of apolipoprotein A-I as the lipid emulsifier and LCAT activator. Specific fluorescence detection of DHE ester synthesis is achieved by employing cholesterol oxidase to selectively render unesterified DHE nonfluorescent. The assay accurately detects LCAT activity in buffer and in plasma that is depleted of apolipoprotein B lipoproteins by selective precipitation. Analysis of LCAT activity in plasmas from control subjects and sickle cell disease (SCD) patients confirms previous reports of reduced LCAT activity in SCD and demonstrates a strong correlation between plasma LCAT activity and LCAT content. The fluorescent assay combines the sensitivity of radiochemical assays with the simplicity of nonradiochemical assays to obtain accurate and robust measurement of LCAT esterification activity. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Interaction of the P-Glycoprotein Multidrug Transporter with Sterols.

    Science.gov (United States)

    Clay, Adam T; Lu, Peihua; Sharom, Frances J

    2015-11-01

    The ABC transporter P-glycoprotein (Pgp, ABCB1) actively exports structurally diverse substrates from within the lipid bilayer, leading to multidrug resistance. Many aspects of Pgp function are altered by the phospholipid environment, but its interactions with sterols remain enigmatic. In this work, the functional interaction between purified Pgp and various sterols was investigated in detergent solution and proteoliposomes. Fluorescence studies showed that dehydroergosterol, cholestatrienol, and NBD-cholesterol interact intimately with Pgp, resulting in both quenching of protein Trp fluorescence and enhancement of sterol fluorescence. Kd values indicated binding affinities in the range of 3-9 μM. Collisional quenching experiments showed that Pgp-bound NBD-cholesterol was protected from the external milieu, resonance energy transfer was observed between Pgp Trp residues and the sterol, and the fluorescence emission of bound sterol was enhanced. These observations suggested an intimate interaction of bound sterols with the transporter at a protected nonpolar site. Cholesterol hemisuccinate altered the thermal unfolding of Pgp and greatly stabilized its basal ATPase activity in both a detergent solution and reconstituted proteoliposomes of certain phospholipids. Other sterols, including dehydroergosterol, did not stabilize the basal ATPase activity of detergent-solubilized Pgp, which suggests that this is not a generalized sterol effect. The phospholipid composition and cholesterol hemisuccinate content of Pgp proteoliposomes altered the basal ATPase and drug transport cycles differently. Sterols may interact with Pgp and modulate its structure and function by occupying part of the drug-binding pocket or by binding to putative consensus cholesterol-binding (CRAC/CARC) motifs located within the transmembrane domains.

  12. Two-photon time-lapse microscopy of BODIPY-cholesterol reveals anomalous sterol diffusion in chinese hamster ovary cells

    DEFF Research Database (Denmark)

    Lund, F. W.; Lomholt, M. A.; Solanko, L. M.

    2012-01-01

    Background: Cholesterol is an important membrane component, but our knowledge about its transport in cells is sparse. Previous imaging studies using dehydroergosterol (DHE), an intrinsically fluorescent sterol from yeast, have established that vesicular and non-vesicular transport modes contribute...... to sterol trafficking from the plasma membrane. Significant photobleaching, however, limits the possibilities for in-depth analysis of sterol dynamics using DHE. Co-trafficking studies with DHE and the recently introduced fluorescent cholesterol analog BODIPY-cholesterol (BChol) suggested that the latter...... probe has utility for prolonged live-cell imaging of sterol transport. Results: We found that BChol is very photostable under two-photon (2P)-excitation allowing the acquisition of several hundred frames without significant photobleaching. Therefore, long-term tracking and diffusion measurements...

  13. Visualization of sterol-rich membrane domains with fluorescently-labeled theonellamides.

    Directory of Open Access Journals (Sweden)

    Shinichi Nishimura

    Full Text Available Cholesterol plays important roles in biological membranes. The cellular location where cholesterol molecules work is prerequisite information for understanding their dynamic action. Bioimaging probes for cholesterol molecules would be the most powerful means for unraveling the complex nature of lipid membranes. However, only a limited number of chemical or protein probes have been developed so far for cytological analysis. Here we show that fluorescently-labeled derivatives of theonellamides act as new sterol probes in mammalian cultured cells. The fluorescent probes recognized cholesterol molecules and bound to liposomes in a cholesterol-concentration dependent manner. The probes showed patchy distribution in the plasma membrane, while they stained specific organelle in the cytoplasm. These data suggest that fTNMs will be valuable sterol probes for studies on the role of sterols in the biological membrane under a variety of experimental conditions.

  14. Osh proteins regulate membrane sterol organization but are not required for sterol movement between the ER and PM

    Science.gov (United States)

    Georgiev, Alexander; Sullivan, David P.; Kersting, Michael C.; Dittman, Jeremy S.; Beh, Christopher T.; Menon, Anant K.

    2011-01-01

    Sterol transport between the endoplasmic reticulum (ER) and plasma membrane (PM) occurs by an ATP-dependent, non-vesicular mechanism that is presumed to require sterol transport proteins (STPs). In Saccharomyces cerevisiae, homologues of the mammalian oxysterol-binding protein (Osh1–7) have been proposed to function as STPs. To evaluate this proposal we took two approaches. First we used dehydroergosterol (DHE) to visualize sterol movement in living cells by fluorescence microscopy. DHE was introduced into the PM under hypoxic conditions and observed to redistribute to lipid droplets on growing the cells aerobically. Redistribution required ATP and the sterol acyltransferase Are2, but did not require PM-derived transport vesicles. DHE redistribution occurred robustly in a conditional yeast mutant (oshΔ osh4-1ts) that lacks all functional Osh proteins at 37°C. In a second approach we used a pulse-chase protocol to analyze the movement of metabolically radiolabeled ergosterol from the ER to the PM. Arrival of radiolabeled ergosterol at the PM was assessed in isolated PM-enriched fractions as well by extracting sterols from intact cells with methyl-β-cyclodextrin. These experiments revealed that whereas ergosterol is transported effectively from the ER to the PM in Osh-deficient cells, the rate at which it moves within the PM to equilibrate with the methyl-β-cyclodextrin extractable sterol pool is slowed. We conclude (i) that the role of Osh proteins in nonvesicular sterol transport between the PM, ER and lipid droplets is either minimal, or subsumed by other mechanisms and (ii) that Osh proteins regulate the organization of sterols at the PM. PMID:21689253

  15. Two-photon time-lapse microscopy of BODIPY-cholesterol reveals anomalous sterol diffusion in chinese hamster ovary cells

    Directory of Open Access Journals (Sweden)

    Lund Frederik W

    2012-10-01

    Full Text Available Abstract Background Cholesterol is an important membrane component, but our knowledge about its transport in cells is sparse. Previous imaging studies using dehydroergosterol (DHE, an intrinsically fluorescent sterol from yeast, have established that vesicular and non-vesicular transport modes contribute to sterol trafficking from the plasma membrane. Significant photobleaching, however, limits the possibilities for in-depth analysis of sterol dynamics using DHE. Co-trafficking studies with DHE and the recently introduced fluorescent cholesterol analog BODIPY-cholesterol (BChol suggested that the latter probe has utility for prolonged live-cell imaging of sterol transport. Results We found that BChol is very photostable under two-photon (2P-excitation allowing the acquisition of several hundred frames without significant photobleaching. Therefore, long-term tracking and diffusion measurements are possible. Two-photon temporal image correlation spectroscopy (2P-TICS provided evidence for spatially heterogeneous diffusion constants of BChol varying over two orders of magnitude from the cell interior towards the plasma membrane, where D ~ 1.3 μm2/s. Number and brightness (N&B analysis together with stochastic simulations suggest that transient partitioning of BChol into convoluted membranes slows local sterol diffusion. We observed sterol endocytosis as well as fusion and fission of sterol-containing endocytic vesicles. The mobility of endocytic vesicles, as studied by particle tracking, is well described by a model for anomalous subdiffusion on short time scales with an anomalous exponent α ~ 0.63 and an anomalous diffusion constant of Dα = 1.95 x 10-3 μm2/sα. On a longer time scale (t > ~5 s, a transition to superdiffusion consistent with slow directed transport with an average velocity of v ~ 6 x 10-3 μm/s was observed. We present an analytical model that bridges the two regimes and fit this model to vesicle

  16. Following Intracellular Cholesterol Transport by Linear and Non-Linear Optical Microscopy of Intrinsically Fluorescent Sterols

    DEFF Research Database (Denmark)

    Wustner, D.

    2012-01-01

    analysis like pixel-wise bleach rate fitting and multiphoton image correlation spectroscopy are introduced. Several applications of the new technology including observation of vectorial sterol trafficking in polarized human hepatoma cells for investigation of reverse cholesterol transport are presented....... the cellular movement of this essential lipid molecule. In this article, a survey of the various methods being used for analysis of sterol trafficking is given. Various classical biochemical methods are presented and their suitability for analysis of sterol trafficking is assessed. Special emphasis...

  17. Multicolor bleach-rate imaging enlightens in vivo sterol transport

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Sage, Daniel

    2011-01-01

    ) labelled with GFP-tagged RME-1 (GFP-RME-1) in the intestine of both, wild-type nematodes and mutant animals lacking intestinal gut granules (glo1-mutants). DHE-enriched intestinal organelles of glo1-mutants were decorated with GFPrme8, a marker for early endosomes. No co-localization was found......, dehydroergosterol (DHE) in the genetically tractable model organism Caenorhabditis elegans (C. elegans). DHE is structurally very similar to cholesterol and ergosterol, two sterols used by the sterol-auxotroph nematode. We developed a new computational method measuring fluorophore bleaching kinetics at every pixel...... with a lysosomal marker, GFP-LMP1. Our new methods hold great promise for further studies on endosomal sterol transport in C. elegans....

  18. Characterization of the sterol and phosphatidylinositol 4-phosphate binding properties of Golgi-associated OSBP-related protein 9 (ORP9.

    Directory of Open Access Journals (Sweden)

    Xinwei Liu

    Full Text Available Oxysterol binding protein (OSBP and OSBP-related proteins (ORPS have a conserved lipid-binding fold that accommodates cholesterol, oxysterols and/or phospholipids. The diversity of OSBP/ORPs and their potential ligands has complicated the analysis of transfer and signalling properties of this mammalian gene family. In this study we explored the use of the fluorescent sterol cholestatrienol (CTL to measure sterol binding by ORP9 and competition by other putative ligands. Relative to cholesterol, CTL and dehydroergosterol (DHE were poor ligands for OSBP. In contrast, both long (ORP9L and short (ORP9S variants of ORP9 rapidly extracted CTL, and to a lesser extent DHE, from liposomes. ORP9L and ORP9S also extracted [32P]phosphatidylinositol 4-phosphate (PI-4P from liposomes, which was inhibited by mutating two conserved histidine residues (HH488,489AA at the entrance to the binding pocket but not by a mutation in the lid region that inhibited cholesterol binding. Results of direct binding and competition assays showed that phosphatidylserine was poorly extracted from liposomes by ORP9 compared to CTL and PI-4P. ORP9L and PI-4P did not co-localize in the trans-Golgi/TGN of HeLa cells, and siRNA silencing of ORP9L expression did not affect PI-4P distribution in the Golgi apparatus. However, transient overexpression of ORP9L or ORP9S in CHO cells, but not the corresponding PI-4P binding mutants, prevented immunostaining of Golgi-associated PI-4P. The apparent sequestration of Golgi PI-4P by ORP9S was identified as a possible mechanism for its growth inhibitory effects. These studies identify ORP9 as a dual sterol/PI-4P binding protein that could regulate PI-4P in the Golgi apparatus.

  19. Bioorthogonal probes for imaging sterols in cells.

    Science.gov (United States)

    Jao, Cindy Y; Nedelcu, Daniel; Lopez, Lyle V; Samarakoon, Thilani N; Welti, Ruth; Salic, Adrian

    2015-03-01

    Cholesterol is a fundamental lipid component of eukaryotic membranes and a precursor of potent signaling molecules, such as oxysterols and steroid hormones. Cholesterol and oxysterols are also essential for Hedgehog signaling, a pathway critical in embryogenesis and cancer. Despite their importance, the use of imaging sterols in cells is currently very limited. We introduce a robust and versatile method for sterol microscopy based on C19 alkyne cholesterol and oxysterol analogues. These sterol analogues are fully functional; they rescue growth of cholesterol auxotrophic cells and faithfully recapitulate the multiple roles that sterols play in Hedgehog signal transduction. Alkyne sterol analogues incorporate efficiently into cellular membranes and can be imaged with high resolution after copper(I)-catalyzed azide-alkyne cycloaddition reaction with fluorescent azides. We demonstrate the use of alkyne sterol probes for visualizing the subcellular distribution of cholesterol and for two-color imaging of sterols and choline phospholipids. Our imaging strategy should be broadly applicable to studying the role of sterols in normal physiology and disease.

  20. Sterol requirements in Drosophila melanogaster

    OpenAIRE

    Almeida de Carvalho, Maria Joao

    2009-01-01

    Sterol is an abundant component of eukaryotic cell membranes and is thought to influence membrane properties such as permeability, fluidity and microdomain formation. Drosophila is an excellent model system in which to study functional requirements for membrane sterol because, although it does not synthesize sterol, it nevertheless requires sterols to complete development. Moreover, Drosophila normally incorporates sterols into cell membranes. Thus, dietary sterol depletion can be used to ...

  1. Sterol metabolism of insects

    NARCIS (Netherlands)

    Ritter, F.J.; Wientjens, W.H.J.M.

    1967-01-01

    This article surveys the present knowledge of the sterol metabolism of insects. It is emphasized that a high degree of purity of the dietary sterols and the climination of the influence of symbionts are essential to present ambiguity in interpreting results. It is pointed out that a sharp distinctio

  2. Plant sterol metabolism. Δ7-Sterol-C5-Desaturase (STE1/DWARF7), Δ5,7-Sterol-Δ7-Reductase (DWARF5) and Δ24-Sterol-Δ24-Reductase (DIMINUTO/DWARF1) show multiple subcellular localizations in Arabidopsis thaliana (Heynh) L

    DEFF Research Database (Denmark)

    Silvestro, Daniele; Andersen, Tonni Grube; Schaller, Hubert

    2013-01-01

    Sterols are crucial lipid components that regulate membrane permeability and fluidity and are the precursors of bioactive steroids. The plant sterols exist as three major forms, free sterols, steryl glycosides and steryl esters. The storage of steryl esters in lipid droplets has been shown...... to contribute to cellular sterol homeostasis. To further document cellular aspects of sterol biosynthesis in plants, we addressed the question of the subcellular localization of the enzymes implicated in the final steps of the post-squalene biosynthetic pathway. In order to create a clear localization map...... of steroidogenic enzymes in cells, the coding regions of ¿(7)-sterol-C(5)-desaturase (STE1/DWARF7), ¿(24)-sterol-¿(24)-reductase (DIMINUTO/DWARF1) and ¿(5,7)-sterol-¿(7)-reductase (DWARF5) were fused to the yellow fluorescent protein (YFP) and transformed into Arabidopsis thaliana mutant lines deficient...

  3. Plant sterol metabolism. Δ7-Sterol-C5-Desaturase (STE1/DWARF7), Δ5,7-Sterol-Δ7-Reductase (DWARF5) and Δ24-Sterol-Δ24-Reductase (DIMINUTO/DWARF1) show multiple subcellular localizations in Arabidopsis thaliana (Heynh) L

    DEFF Research Database (Denmark)

    Silvestro, Daniele; Andersen, Tonni Grube; Schaller, Hubert;

    2013-01-01

    to contribute to cellular sterol homeostasis. To further document cellular aspects of sterol biosynthesis in plants, we addressed the question of the subcellular localization of the enzymes implicated in the final steps of the post-squalene biosynthetic pathway. In order to create a clear localization map...... of steroidogenic enzymes in cells, the coding regions of ¿(7)-sterol-C(5)-desaturase (STE1/DWARF7), ¿(24)-sterol-¿(24)-reductase (DIMINUTO/DWARF1) and ¿(5,7)-sterol-¿(7)-reductase (DWARF5) were fused to the yellow fluorescent protein (YFP) and transformed into Arabidopsis thaliana mutant lines deficient...... in the corresponding enzymes. All fusion proteins were found to localize in the endoplasmic reticulum in functionally complemented plants. The results show that both ¿(5,7)-sterol-¿(7)-reductase and ¿(24)-sterol-¿(24)-reductase are in addition localized to the plasma membrane, whereas ¿(7)-sterol-C(5)-desaturase...

  4. Sterol Synthesis in Diverse Bacteria.

    Science.gov (United States)

    Wei, Jeremy H; Yin, Xinchi; Welander, Paula V

    2016-01-01

    Sterols are essential components of eukaryotic cells whose biosynthesis and function has been studied extensively. Sterols are also recognized as the diagenetic precursors of steranes preserved in sedimentary rocks where they can function as geological proxies for eukaryotic organisms and/or aerobic metabolisms and environments. However, production of these lipids is not restricted to the eukaryotic domain as a few bacterial species also synthesize sterols. Phylogenomic studies have identified genes encoding homologs of sterol biosynthesis proteins in the genomes of several additional species, indicating that sterol production may be more widespread in the bacterial domain than previously thought. Although the occurrence of sterol synthesis genes in a genome indicates the potential for sterol production, it provides neither conclusive evidence of sterol synthesis nor information about the composition and abundance of basic and modified sterols that are actually being produced. Here, we coupled bioinformatics with lipid analyses to investigate the scope of bacterial sterol production. We identified oxidosqualene cyclase (Osc), which catalyzes the initial cyclization of oxidosqualene to the basic sterol structure, in 34 bacterial genomes from five phyla (Bacteroidetes, Cyanobacteria, Planctomycetes, Proteobacteria, and Verrucomicrobia) and in 176 metagenomes. Our data indicate that bacterial sterol synthesis likely occurs in diverse organisms and environments and also provides evidence that there are as yet uncultured groups of bacterial sterol producers. Phylogenetic analysis of bacterial and eukaryotic Osc sequences confirmed a complex evolutionary history of sterol synthesis in this domain. Finally, we characterized the lipids produced by Osc-containing bacteria and found that we could generally predict the ability to synthesize sterols. However, predicting the final modified sterol based on our current knowledge of sterol synthesis was difficult. Some bacteria

  5. Plant sterol metabolism. Δ(7-Sterol-C5-desaturase (STE1/DWARF7, Δ(5,7-sterol-Δ(7-reductase (DWARF5 and Δ(24-sterol-Δ(24-reductase (DIMINUTO/DWARF1 show multiple subcellular localizations in Arabidopsis thaliana (Heynh L.

    Directory of Open Access Journals (Sweden)

    Daniele Silvestro

    Full Text Available Sterols are crucial lipid components that regulate membrane permeability and fluidity and are the precursors of bioactive steroids. The plant sterols exist as three major forms, free sterols, steryl glycosides and steryl esters. The storage of steryl esters in lipid droplets has been shown to contribute to cellular sterol homeostasis. To further document cellular aspects of sterol biosynthesis in plants, we addressed the question of the subcellular localization of the enzymes implicated in the final steps of the post-squalene biosynthetic pathway. In order to create a clear localization map of steroidogenic enzymes in cells, the coding regions of Δ(7-sterol-C(5-desaturase (STE1/DWARF7, Δ(24-sterol-Δ(24-reductase (DIMINUTO/DWARF1 and Δ(5,7-sterol-Δ(7-reductase (DWARF5 were fused to the yellow fluorescent protein (YFP and transformed into Arabidopsis thaliana mutant lines deficient in the corresponding enzymes. All fusion proteins were found to localize in the endoplasmic reticulum in functionally complemented plants. The results show that both Δ(5,7-sterol-Δ(7-reductase and Δ(24-sterol-Δ(24-reductase are in addition localized to the plasma membrane, whereas Δ(7-sterol-C(5-desaturase was clearly detected in lipid particles. These findings raise new challenging questions about the spatial and dynamic cellular organization of sterol biosynthesis in plants.

  6. The effects of sterol structure upon sterol esterification.

    Science.gov (United States)

    Lin, Don S; Steiner, Robert D; Merkens, Louise S; Pappu, Anuradha S; Connor, William E

    2010-01-01

    Cholesterol is esterified in mammals by two enzymes: LCAT (lecithin cholesterol acyltransferase) in plasma and ACAT(1) and ACAT(2) (acyl-CoA cholesterol acyltransferases) in the tissues. We hypothesized that the sterol structure may have significant effects on the outcome of esterification by these enzymes. To test this hypothesis, we analyzed sterol esters in plasma and tissues in patients having non-cholesterol sterols (sitosterolemia and Smith-Lemli-Opitz syndrome). The esterification of a given sterol was defined as the sterol ester percentage of total sterols. The esterification of cholesterol in plasma by LCAT was 67% and in tissues by ACAT was 64%. Esterification of nine sterols (cholesterol, cholestanol, campesterol, stigmasterol, sitosterol, campestanol, sitostanol, 7-dehydrocholesterol and 8-dehydrocholesterol) was examined. The relative esterification (cholesterol being 1.0) of these sterols by the plasma LCAT was 1.00, 0.95, 0.89, 0.40, 0.85, 0.82 and 0.80, 0.69 and 0.82, respectively. The esterification by the tissue ACAT was 1.00, 1.29, 0.75, 0.49, 0.45, 1.21 and 0.74, respectively. The predominant fatty acid of the sterol esters was linoleic acid for LCAT and oleic acid for ACAT. We compared the esterification of two sterols differing by only one functional group (a chemical group attached to sterol nucleus) and were able to quantify the effects of individual functional groups on sterol esterification. The saturation of the A ring of cholesterol increased ester formation by ACAT by 29% and decreased the esterification by LCAT by 5.9%. Esterification by ACAT and LCAT was reduced, respectively, by 25 and 11% by the presence of an additional methyl group on the side chain of cholesterol at the C-24 position. This data supports our hypothesis that the structure of the sterol substrate has a significant effect on its esterification by ACAT or LCAT.

  7. Identification of a novel dehydroergosterol enhancing microglial anti-inflammatory activity in a dairy product fermented with Penicillium candidum.

    Directory of Open Access Journals (Sweden)

    Yasuhisa Ano

    Full Text Available Despite the ever-increasing number of dementia patients worldwide, fundamental therapeutic approaches to treat this disease remain to be established. Preventive approaches such as diet, exercise and learning attract attention. Several epidemiological studies suggest that ingestion of fermented dairy products prevents cognitive decline in the elderly. These reports indicate that specific ingredients in the fermented dairy products elicit an anti-inflammatory or anti-oxidative activity that facilitates neuroprotection. The responsible components remain to be investigated. A number of studies have shown that inflammation caused by microglia is closely related to exaggeration of the pathology and cognitive decline seen in the elderly. Many researchers have proposed that controlling microglial activities could be effective in preventing and possibly curing dementia. In the present study, to elucidate specific compounds that regulate microglial activity from dairy products, repeated purification by HPLC, combined with evaluation using primary microglia, facilitated the identification of dehydroergosterol (DHE as a novel component of the extract that enhances microglial anti-inflammatory activity. DHE contains three conjugated double bonds in a steroid ring system and is an analogue of ergosterol. Despite their related chemical structures, the anti-inflammatory activity of DHE is markedly stronger than that of ergosterol. P. candidum for camembert cheese produces DHE, but P. Roqueforti for blue cheese and Aspergillus do not. DHE also induces CD11b-positive microglia cells into CD206-positive M2 type microglia. Neurotoxicity and neuronal cell death induced by excessively activated microglia is suppressed by treatment with DHE. Thus, this is the first report to demonstrate that DHE, identified as a responsible compound in dairy products, can induce microglia into a preferable phenotype for our brain environment and can be safely introduced into the body

  8. Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast

    DEFF Research Database (Denmark)

    Marek, Magdalena; Silvestro, Daniele; Fredslund, Maria D.

    2014-01-01

    Sterol uptake in fungi is a multistep process that involves interaction between external sterols and the cell wall, incorporation of sterol molecules into the plasma membrane, and subsequent integration into intracellular membranes for turnover. ATP-binding cassette (ABC) transporters have been...... implicated in sterol uptake, but key features of their activity remain to be elucidated. Here, we apply fluorescent cholesterol (NBD-cholesterol) to monitor sterol uptake under anaerobic and aerobic conditions in two fungal species, Candida glabrata (Cg) and Saccharomyces cerevisiae (Sc). We found...... that in both fungal species, ABC transporter-dependent uptake of cholesterol under anaerobic conditions and in mutants lacking HEM1 gene is promoted in the presence of the serum protein albumin that is able to bind the sterol molecule. Furthermore, the C. glabrata ABC transporter CgAus1p expressed in S...

  9. "Dinoflagellate Sterols" in marine diatoms.

    Science.gov (United States)

    Giner, José-Luis; Wikfors, Gary H

    2011-10-01

    Sterol compositions for three diatom species, recently shown to contain sterols with side chains typically found in dinoflagellates, were determined by HPLC and ¹H NMR spectroscopic analyses. The centric diatom Triceratium dubium (=Biddulphia sp., CCMP 147) contained the highest percentage of 23-methylated sterols (37.2% (24R)-23-methylergosta-5,22-dienol), whereas the pennate diatom Delphineis sp. (CCMP 1095) contained the cyclopropyl sterol gorgosterol, as well as the 27-norsterol occelasterol. The sterol composition of Ditylum brightwellii (CCMP 358) was the most complex, containing Δ⁰- and Δ⁷-sterols, in addition to the predominant Δ⁵-sterols. A pair of previously unknown sterols, stigmasta-5,24,28-trienol and stigmasta-24,28-dienol, were detected in D. brightwellii and their structures were determined by NMR spectroscopic analysis and by synthesis of the former sterol from saringosterol. Also detected in D. brightwellii was the previously unknown 23-methylcholesta-7,22-dienol. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Plant Sterols: Diversity, Biosynthesis, and Physiological Functions.

    Science.gov (United States)

    Valitova, J N; Sulkarnayeva, A G; Minibayeva, F V

    2016-08-01

    Sterols, which are isoprenoid derivatives, are structural components of biological membranes. Special attention is now being given not only to their structure and function, but also to their regulatory roles in plants. Plant sterols have diverse composition; they exist as free sterols, sterol esters with higher fatty acids, sterol glycosides, and acylsterol glycosides, which are absent in animal cells. This diversity of types of phytosterols determines a wide spectrum of functions they play in plant life. Sterols are precursors of a group of plant hormones, the brassinosteroids, which regulate plant growth and development. Furthermore, sterols participate in transmembrane signal transduction by forming lipid microdomains. The predominant sterols in plants are β-sitosterol, campesterol, and stigmasterol. These sterols differ in the presence of a methyl or an ethyl group in the side chain at the 24th carbon atom and are named methylsterols or ethylsterols, respectively. The balance between 24-methylsterols and 24-ethylsterols is specific for individual plant species. The present review focuses on the key stages of plant sterol biosynthesis that determine the ratios between the different types of sterols, and the crosstalk between the sterol and sphingolipid pathways. The main enzymes involved in plant sterol biosynthesis are 3-hydroxy-3-methylglutaryl-CoA reductase, C24-sterol methyltransferase, and C22-sterol desaturase. These enzymes are responsible for maintaining the optimal balance between sterols. Regulation of the ratios between the different types of sterols and sterols/sphingolipids can be of crucial importance in the responses of plants to stresses.

  11. Phylogenetic distribution of fungal sterols.

    Directory of Open Access Journals (Sweden)

    John D Weete

    Full Text Available BACKGROUND: Ergosterol has been considered the "fungal sterol" for almost 125 years; however, additional sterol data superimposed on a recent molecular phylogeny of kingdom Fungi reveals a different and more complex situation. METHODOLOGY/PRINCIPAL FINDINGS: The interpretation of sterol distribution data in a modern phylogenetic context indicates that there is a clear trend from cholesterol and other Delta(5 sterols in the earliest diverging fungal species to ergosterol in later diverging fungi. There are, however, deviations from this pattern in certain clades. Sterols of the diverse zoosporic and zygosporic forms exhibit structural diversity with cholesterol and 24-ethyl -Delta(5 sterols in zoosporic taxa, and 24-methyl sterols in zygosporic fungi. For example, each of the three monophyletic lineages of zygosporic fungi has distinctive major sterols, ergosterol in Mucorales, 22-dihydroergosterol in Dimargaritales, Harpellales, and Kickxellales (DHK clade, and 24-methyl cholesterol in Entomophthorales. Other departures from ergosterol as the dominant sterol include: 24-ethyl cholesterol in Glomeromycota, 24-ethyl cholest-7-enol and 24-ethyl-cholesta-7,24(28-dienol in rust fungi, brassicasterol in Taphrinales and hypogeous pezizalean species, and cholesterol in Pneumocystis. CONCLUSIONS/SIGNIFICANCE: Five dominant end products of sterol biosynthesis (cholesterol, ergosterol, 24-methyl cholesterol, 24-ethyl cholesterol, brassicasterol, and intermediates in the formation of 24-ethyl cholesterol, are major sterols in 175 species of Fungi. Although most fungi in the most speciose clades have ergosterol as a major sterol, sterols are more varied than currently understood, and their distribution supports certain clades of Fungi in current fungal phylogenies. In addition to the intellectual importance of understanding evolution of sterol synthesis in fungi, there is practical importance because certain antifungal drugs (e.g., azoles target reactions in

  12. Survival strategies of a sterol auxotroph

    Science.gov (United States)

    Carvalho, Maria; Schwudke, Dominik; Sampaio, Julio L.; Palm, Wilhelm; Riezman, Isabelle; Dey, Gautam; Gupta, Gagan D.; Mayor, Satyajit; Riezman, Howard; Shevchenko, Andrej; Kurzchalia, Teymuras V.; Eaton, Suzanne

    2010-01-01

    The high sterol concentration in eukaryotic cell membranes is thought to influence membrane properties such as permeability, fluidity and microdomain formation. Drosophila cannot synthesize sterols, but do require them for development. Does this simply reflect a requirement for sterols in steroid hormone biosynthesis, or is bulk membrane sterol also essential in Drosophila? If the latter is true, how do they survive fluctuations in sterol availability and maintain membrane homeostasis? Here, we show that Drosophila require both bulk membrane sterol and steroid hormones in order to complete adult development. When sterol availability is restricted, Drosophila larvae modulate their growth to maintain membrane sterol levels within tight limits. When dietary sterol drops below a minimal threshold, larvae arrest growth and development in a reversible manner. Strikingly, membrane sterol levels in arrested larvae are dramatically reduced (dropping sixfold on average) in most tissues except the nervous system. Thus, sterols are dispensable for maintaining the basic membrane biophysical properties required for cell viability; these functions can be performed by non-sterol lipids when sterols are unavailable. However, bulk membrane sterol is likely to have essential functions in specific tissues during development. In tissues in which sterol levels drop, the overall level of sphingolipids increases and the proportion of different sphingolipid variants is altered. These changes allow survival, but not growth, when membrane sterol levels are low. This relationship between sterols and sphingolipids could be an ancient and conserved principle of membrane homeostasis. PMID:20940226

  13. Phylogenetic Distribution of Fungal Sterols

    Science.gov (United States)

    Weete, John D.; Abril, Maritza; Blackwell, Meredith

    2010-01-01

    Background Ergosterol has been considered the “fungal sterol” for almost 125 years; however, additional sterol data superimposed on a recent molecular phylogeny of kingdom Fungi reveals a different and more complex situation. Methodology/Principal Findings The interpretation of sterol distribution data in a modern phylogenetic context indicates that there is a clear trend from cholesterol and other Δ5 sterols in the earliest diverging fungal species to ergosterol in later diverging fungi. There are, however, deviations from this pattern in certain clades. Sterols of the diverse zoosporic and zygosporic forms exhibit structural diversity with cholesterol and 24-ethyl -Δ5 sterols in zoosporic taxa, and 24-methyl sterols in zygosporic fungi. For example, each of the three monophyletic lineages of zygosporic fungi has distinctive major sterols, ergosterol in Mucorales, 22-dihydroergosterol in Dimargaritales, Harpellales, and Kickxellales (DHK clade), and 24-methyl cholesterol in Entomophthorales. Other departures from ergosterol as the dominant sterol include: 24-ethyl cholesterol in Glomeromycota, 24-ethyl cholest-7-enol and 24-ethyl-cholesta-7,24(28)-dienol in rust fungi, brassicasterol in Taphrinales and hypogeous pezizalean species, and cholesterol in Pneumocystis. Conclusions/Significance Five dominant end products of sterol biosynthesis (cholesterol, ergosterol, 24-methyl cholesterol, 24-ethyl cholesterol, brassicasterol), and intermediates in the formation of 24-ethyl cholesterol, are major sterols in 175 species of Fungi. Although most fungi in the most speciose clades have ergosterol as a major sterol, sterols are more varied than currently understood, and their distribution supports certain clades of Fungi in current fungal phylogenies. In addition to the intellectual importance of understanding evolution of sterol synthesis in fungi, there is practical importance because certain antifungal drugs (e.g., azoles) target reactions in the synthesis of

  14. Study of Behavior of Sterols at Interfaces

    Science.gov (United States)

    Klein, P. D.; Knight, J. C.; Szczepanik, P. A.

    1968-01-01

    Behavior of sterols and sterol acetates on various types of interfaces indicates that the function of a sterol depends upon a surface orientation and surface energy of the interface. Column-chromatographic techniques determine the retention volume of various sterols under standard conditions.

  15. Bioactivities of six sterols isolated from marine invertebrates.

    Science.gov (United States)

    Zhou, Xuefeng; Sun, Jianfan; Ma, Wanlei; Fang, Wei; Chen, Zhefan; Yang, Bin; Liu, Yonghong

    2014-02-01

    Epidioxy sterols and sterols with special side chains, such as hydroperoxyl sterols, usually obtained from marine natural products, are attractive for bioactivities. To isolate and screen bioactive and special sterols from China Sea invertebrates. Two hydroperoxyl sterols (1 and 2) from the sponge Xestospongia testudinaria Lamarck (Petrosiidae), three epidioxy sterols (3-5) from the sea urchin Glyptocidaris crenularis A. Agassiz (Glyptocidaridae), sponge Mycale sp. (Mycalidae) and gorgonian Dichotella gemmacea Milne Edwards and Haime (Ellisellidae) and an unusual sterol with 25-acetoxy-19-oate (6) also from D. gemmacea were obtained and identified. Using high-throughput screening, their bioactivities were tested toward Forkhead box O 3a (Foxo3a), 3-hydroxy-3-methylglutaryl CoA reductase gene fluorescent protein (HMGCR-GFP), nuclear factor kappa B (NF-κB) luciferase, peroxisome proliferator-activated receptor-γ co-activator 1α (PGC-1α), protein-tyrosine phosphatase 1B (PTP1B), mitochondrial membrane permeabilization (MMP) and adenosine monophosphate-activated protein kinase. Their structures were determined by comparing their nuclear magnetic resonance data with those reported in the literature. Three epidioxy sterols (3-5) showed inhibitory activities toward Foxo3a, HMGCR-GFP and NF-κB-luciferase with the IC50 values 4.9-6.8 μg/mL. The hydroperoxyl sterol 29-hydroperoxystigmasta-5,24(28)-dien-3-ol (2) had diverse inhibitory activities against Foxo3a, HMGCR-GFP, NF-κB-luciferase, PGC-1α, PTP1B and MMP, with IC50 values of 3.8-19.1 μg/mL. The bioactivities of 3-5 showed that 5α,8α-epidioxy is the active group. Otherwise, the most plausible biosynthesis pathway for 1 and 2 in sponge involves the abstraction of an allylic proton by an activated oxygen, such as O2, along with migration of carbon-carbon double bond. Therefore, the bioactive and unstable steroid should be biosynthesized in sponge under a special ecological environment to act as a defensive

  16. Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast.

    Science.gov (United States)

    Marek, Magdalena; Silvestro, Daniele; Fredslund, Maria D; Andersen, Tonni G; Pomorski, Thomas G

    2014-12-01

    Sterol uptake in fungi is a multistep process that involves interaction between external sterols and the cell wall, incorporation of sterol molecules into the plasma membrane, and subsequent integration into intracellular membranes for turnover. ATP-binding cassette (ABC) transporters have been implicated in sterol uptake, but key features of their activity remain to be elucidated. Here, we apply fluorescent cholesterol (NBD-cholesterol) to monitor sterol uptake under anaerobic and aerobic conditions in two fungal species, Candida glabrata (Cg) and Saccharomyces cerevisiae (Sc). We found that in both fungal species, ABC transporter-dependent uptake of cholesterol under anaerobic conditions and in mutants lacking HEM1 gene is promoted in the presence of the serum protein albumin that is able to bind the sterol molecule. Furthermore, the C. glabrata ABC transporter CgAus1p expressed in S. cerevisiae requires the presence of serum or albumin for efficient cholesterol uptake. These results suggest that albumin can serve as sterol donor in ABC transporter-dependent sterol uptake, a process potentially important for growth of C. glabrata inside infected humans.

  17. Sterols of the fungi - Distribution and biosynthesis

    Science.gov (United States)

    Weete, J. D.

    1973-01-01

    The importance of sterols in the growth and reproduction in fungi is becoming increasingly apparent. This article concerns the composition and biosynthesis of ergosterol in these organisms. Comparison to plant and animal sterol formation are made.

  18. Distribution and functions of sterols and sphingolipids.

    Science.gov (United States)

    Hannich, J Thomas; Umebayashi, Kyohei; Riezman, Howard

    2011-05-01

    Sterols and sphingolipids are considered mainly eukaryotic lipids even though both are present in some prokaryotes, with sphingolipids being more widespread than sterols. Both sterols and sphingolipids differ in their structural features in vertebrates, plants, and fungi. Interestingly, some invertebrates cannot synthesize sterols de novo and seem to have a reduced dependence on sterols. Sphingolipids and sterols are found in the plasma membrane, but we do not have a clear picture of their precise intracellular localization. Advances in lipidomics and subcellular fractionation should help to improve this situation. Genetic approaches have provided insights into the diversity of sterol and sphingolipid functions in eukaryotes providing evidence that these two lipid classes function together. Intermediates in sphingolipid biosynthesis and degradation are involved in signaling pathways, whereas sterol structures are converted to hormones. Both lipids have been implicated in regulating membrane trafficking.

  19. Sterols of the fungi - Distribution and biosynthesis

    Science.gov (United States)

    Weete, J. D.

    1973-01-01

    The importance of sterols in the growth and reproduction in fungi is becoming increasingly apparent. This article concerns the composition and biosynthesis of ergosterol in these organisms. Comparison to plant and animal sterol formation are made.

  20. Analysis of Cholesterol Trafficking with Fluorescent Probes

    DEFF Research Database (Denmark)

    Maxfield, Frederick R.; Wustner, Daniel

    2012-01-01

    Cholesterol plays an important role in determining the biophysical properties of biological membranes, and its concentration is tightly controlled by homeostatic processes. The intracellular transport of cholesterol among organelles is a key part of the homeostatic mechanism, but sterol transport...... that can bind to cholesterol to reveal its distribution in cells. We also discuss the use of intrinsically fluorescent sterols that closely mimic cholesterol, as well as some minimally modified fluorophore-labeled sterols. Methods for imaging these sterols by conventional fluorescence microscopy...... and by multiphoton microscopy are described. Some label-free methods for imaging cholesterol itself are also discussed briefly....

  1. Universal Behavior of Membranes with Sterols

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Rowat, Amy C.; Brief, E.

    2006-01-01

    Lanosterol is the biosynthetic precursor of cholesterol and ergosterol, sterols that predominate in the membranes of mammals and lower eukaryotes, respectively. These three sterols are structurally quite similar, yet their relative effects on membranes have been shown to differ. Here we study...... to different degrees by these structurally distinct sterols, yet nonetheless exhibit universal behavior....

  2. Plant Sterol Diversity in Pollen from Angiosperms.

    Science.gov (United States)

    Villette, Claire; Berna, Anne; Compagnon, Vincent; Schaller, Hubert

    2015-08-01

    Here we have examined the composition of free sterols and steryl esters of pollen from selected angiosperm species, as a first step towards a comprehensive analysis of sterol biogenesis in the male gametophyte. We detected four major sterol structural groups: cycloartenol derivatives bearing a 9β,19-cyclopropyl group, sterols with a double bond at C-7(8), sterols with a double bond at C-5(6), and stanols. All these groups were unequally distributed among species. However, the distribution of sterols as free sterols or as steryl esters in pollen grains indicated that free sterols were mostly Δ(5)-sterols and that steryl esters were predominantly 9β,19-cyclopropyl sterols. In order to link the sterol composition of a pollen grain at anthesis with the requirement for membrane lipid constituents of the pollen tube, we germinated pollen grains from Nicotiana tabacum, a model plant in reproductive biology. In the presence of radiolabelled mevalonic acid and in a time course series of measurements, we showed that cycloeucalenol was identified as the major neosynthesized sterol. Furthermore, the inhibition of cycloeucalenol neosynthesis by squalestatin was in full agreement with a de novo biogenesis and an apparent truncated pathway in the pollen tube.

  3. Characteristics of sterol uptake in Saccharomyces cerevisiae.

    OpenAIRE

    Lorenz, R T; Rodriguez, R J; Lewis, T A; Parks, L W

    1986-01-01

    A Saccharomyces cerevisiae sterol auxotroph, FY3 (alpha hem1 erg7 ura), was used to probe the characteristics of sterol uptake in S. cerevisiae. The steady-state cellular concentration of free sterol at the late exponential phase of growth could be adjusted within a 10-fold range by varying the concentration of exogenously supplied sterol. When cultured on 1 microgram of sterol ml-1, the cells contained a minimal cellular free-cholesterol concentration of 0.85 nmol/mg (dry weight) and were te...

  4. Multiple Functions of Sterols in Yeast Endocytosis

    Science.gov (United States)

    Heese-Peck, Antje; Pichler, Harald; Zanolari, Bettina; Watanabe, Reika; Daum, Günther; Riezman, Howard

    2002-01-01

    Sterols are essential factors for endocytosis in animals and yeast. To investigate the sterol structural requirements for yeast endocytosis, we created a variety of ergΔ mutants, each accumulating a distinct set of sterols different from ergosterol. Mutant erg2Δerg6Δ and erg3Δerg6Δ cells exhibit a strong internalization defect of the α-factor receptor (Ste2p). Specific sterol structures are necessary for pheromone-dependent receptor hyperphosphorylation, a prerequisite for internalization. The lack of phosphorylation is not due to a defect in Ste2p localization or in ligand–receptor interaction. Contrary to most known endocytic factors, sterols seem to function in internalization independently of actin. Furthermore, sterol structures are required at a postinternalization step of endocytosis. ergΔ cells were able to take up the membrane marker FM4-64, but exhibited defects in FM4-64 movement through endosomal compartments to the vacuole. Therefore, there are at least two roles for sterols in endocytosis. Based on sterol analysis, the sterol structural requirements for these two processes were different, suggesting that sterols may have distinct functions at different places in the endocytic pathway. Interestingly, sterol structures unable to support endocytosis allowed transport of the glycosylphosphatidylinositol-anchored protein Gas1p from the endoplasmic reticulum to Golgi compartment. PMID:12181337

  5. C26 sterol in a human urine.

    Science.gov (United States)

    Ikekawa, N; Fujimoto, Y; Isiguro, M; Suwa, S; Hirayama, Y; Mizunuma, H

    1979-06-15

    A new C26 sterol, 22-trans-27-norcholesta-5,22-dien-3 beta-ol, was found in the urine of a 6-year-old girl, with a clinical diagnosis of congenital adrenal hyperplasia of the salt losing type, accompanied by symptoms of mixed sex anatomy and skin pigmentation. The structure of the sterol was determined by comparison with the synthetic compound. The sterol was also detected in ther serum. This appears to be the first case in which a C26 sterol has occurred in mammalia.

  6. The sterols of calcareous sponges (Calcarea, Porifera).

    Science.gov (United States)

    Hagemann, Andrea; Voigt, Oliver; Wörheide, Gert; Thiel, Volker

    2008-11-01

    Sponges are sessile suspension-feeding organisms whose internal phylogenetic relationships are still the subject of intense debate. Sterols may have the potential to be used as independent markers to test phylogenetic hypotheses. Twenty representative specimens of calcareous sponges (class Calcarea, phylum Porifera) with a broad coverage within both subclasses Calcinea and Calcaronea were analysed for their sterol content. Two major pseudohomologous series were found, accompanied by some additional sterols. The first series encompassing conventional C(27) to C(29)Delta(5,7,22) sterols represented the major sterols, with ergosterol (ergosta-5,7,22-trien-3beta-ol, C(28)Delta(5,7,22)) being most prominent in many species. The second series consisted of unusual C(27) to C(29)Delta(5,7,9(11),22) sterols. Cholesterol occurred sporadically, mostly in trace amounts. The sterol patterns did not resolve intraclass phylogenetic relationships, namely the distinction between the subclasses, Calcinea and Calcaronea. This pointed towards major calcarean lipid traits being established prior to the separation of subclasses. Furthermore, calcarean sterol patterns clearly differ from those found in Hexactinellida, whereas partial overlap occurred with some Demospongiae. Hence, sterols only partly reflect the phylogenetic separation of Calcarea from both of the other poriferan classes that was proposed by recent molecular work and fatty acid analyses.

  7. Depot sterols in comparisons with structural sterols in Cancer pagurus and Eriocheir sinensis

    NARCIS (Netherlands)

    Zandee, D.I.; Kruitwagen, E.C.J.

    1975-01-01

    The differences in sterol content and sterol composition between the midgut gland and remaining parts (structural lipids) of male and female specimens of Cancer pagurus and Eriocheir sinensis are investigated. There are no differences in sterol content in the structural lipids between male and femal

  8. Building Synthetic Sterols Computationally - Unlocking the Secrets of Evolution?

    DEFF Research Database (Denmark)

    Róg, Tomasz; Pöyry, Sanja; Vattulainen, Ilpo

    2015-01-01

    Cholesterol is vital in regulating the physical properties of animal cell membranes. While it remains unclear what renders cholesterol so unique, it is known that other sterols are less capable in modulating membrane properties, and there are membrane proteins whose function is dependent on chole......Cholesterol is vital in regulating the physical properties of animal cell membranes. While it remains unclear what renders cholesterol so unique, it is known that other sterols are less capable in modulating membrane properties, and there are membrane proteins whose function is dependent...... on cholesterol. Practical applications of cholesterol include its use in liposomes in drug delivery and cosmetics, cholesterol-based detergents in membrane protein crystallography, its fluorescent analogs in studies of cholesterol transport in cells and tissues, etc. Clearly, in spite of their difficult...... dynamics simulation studies that have predicted new synthetic sterols with properties comparable to those of cholesterol. We also discuss more recent experimental studies that have vindicated these predictions. The paper highlights the strength of computational simulations in making predictions...

  9. Dietary plant sterols accumulate in the brain

    NARCIS (Netherlands)

    Jansen, PJ; Lutjohann, D; Abildayeva, K; Vanmierlo, T; Plosch, T; Plat, J; von Bergmann, K; Groen, AK; Ramaekers, FCS; Kuipers, F; Mulder, M

    2006-01-01

    Dietary plant sterols and cholesterol have a comparable chemical structure. It is generally assumed that cholesterol and plant sterols do not cross the blood-brain barrier, but quantitative data are lacking. Here, we report that mice deficient for ATP-binding cassette transporter G5 (Abcg5) or Abcg8

  10. Comparative molecular modelling of biologically active sterols

    Science.gov (United States)

    Baran, Mariusz; Mazerski, Jan

    2015-04-01

    Membrane sterols are targets for a clinically important antifungal agent - amphotericin B. The relatively specific antifungal action of the drug is based on a stronger interaction of amphotericin B with fungal ergosterol than with mammalian cholesterol. Conformational space occupied by six sterols has been defined using the molecular dynamics method to establish if the conformational features correspond to the preferential interaction of amphotericin B with ergosterol as compared with cholesterol. The compounds studied were chosen on the basis of structural features characteristic for cholesterol and ergosterol and on available experimental data on the ability to form complexes with the antibiotic. Statistical analysis of the data obtained has been performed. The results show similarity of the conformational spaces occupied by all the sterols tested. This suggests that the conformational differences of sterol molecules are not the major feature responsible for the differential sterol - drug affinity.

  11. Sterols and sterol oxides in the potato products, and sterols in the vegetable oils used for industrial frying operations

    Directory of Open Access Journals (Sweden)

    Dutta, Paresh Chandra

    1996-04-01

    Full Text Available The objective of this study was to determine the composition of sterols in vegetable oils used in industrial frying operations, and sterols and sterol oxides in the fried potato products. The sterols and sterol oxides were enriched by saponification of oils and by solid phase extraction. Preparative thin layer chromatography, capillary gas chromatography, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy, were used to give qualitative and quantitative data. The results revealed that the content of desmethylsterols in palm oil, sunflower oil, high oleic sunflower oil, and rapeseed oil/palm oil blend were, 790, 4501, 3550, and 4497 ppm, respectively. Sitosterol was the major desmethylsterol in all samples. Palm oil also contained the lowest levels of total unsaponifiables. The sterols and unsaponifiable contents in sunflower oil were, to some extent, higher than in higholeic sunflower oil. The compositions of sterols after two days of frying were neither markedly different in the oils nor in the potato products fried in these oils compared with the original oils. Isomerised sterols were tentatively quantified to account for 10 ppm, 50 ppm and 20 ppm, in rapeseed oil/palm oil blend, sunflower oil, and high-oleic sunflower oils, respectively. Lipids extracted from French fries prepared in rapeseed oil/palm oil blend contained the highest levels of total sterol oxides, 191 ppm, and epoxides of both sitosterol and campesterol were the major contributors, together at a level of 172 ppm. On the other hand, lipids extracted from French fries prepared in sunflower oil and high-oleic sunflower oil contained 7α-hydroxy-, 7β-hydroxy-, 7-keto- and both epimers of epoxysitosterol, generally in equal amounts. All samples also contained small amounts of different oxidation products of campesterol and stigmasterol.

  12. Thresholds for sterol-limited growth of Daphnia magna: a comparative approach using 10 different sterols.

    Science.gov (United States)

    Martin-Creuzburg, Dominik; Oexle, Sarah; Wacker, Alexander

    2014-09-01

    Arthropods are incapable of synthesizing sterols de novo and thus require a dietary source to cover their physiological demands. The most prominent sterol in animal tissues is cholesterol, which is an indispensable structural component of cell membranes and serves as precursor for steroid hormones. Instead of cholesterol, plants and algae contain a variety of different phytosterols. Consequently, herbivorous arthropods have to metabolize dietary phytosterols to cholesterol to meet their requirements for growth and reproduction. Here, we investigated sterol-limited growth responses of the freshwater herbivore Daphnia magna by supplementing a sterol-free diet with increasing amounts of 10 different phytosterols and comparing thresholds for sterol-limited growth. In addition, we analyzed the sterol composition of D. magna to explore sterol metabolic constraints and bioconversion capacities. We show that dietary phytosterols strongly differ in their potential to support somatic growth of D. magna. The dietary threshold concentrations obtained by supplementing the different sterols cover a wide range (3.5-34.4 μg mg C(-1)) and encompass the one for cholesterol (8.9 μg mg C(-1)), indicating that certain phytosterols are more efficient in supporting somatic growth than cholesterol (e.g., fucosterol, brassicasterol) while others are less efficient (e.g., dihydrocholesterol, lathosterol). The dietary sterol concentration gradients revealed that the poor quality of particular sterols can be alleviated partially by increasing dietary concentrations, and that qualitative differences among sterols are most pronounced at low to moderate dietary concentrations. We infer that the dietary sterol composition has to be considered in zooplankton nutritional ecology to accurately assess potential sterol limitations under field conditions.

  13. Sterols in spermatogenesis and sperm maturation

    Science.gov (United States)

    Keber, Rok; Rozman, Damjana; Horvat, Simon

    2013-01-01

    Mammalian spermatogenesis is a complex developmental program in which a diploid progenitor germ cell transforms into highly specialized spermatozoa. One intriguing aspect of sperm production is the dynamic change in membrane lipid composition that occurs throughout spermatogenesis. Cholesterol content, as well as its intermediates, differs vastly between the male reproductive system and nongonadal tissues. Accumulation of cholesterol precursors such as testis meiosis-activating sterol and desmosterol is observed in testes and spermatozoa from several mammalian species. Moreover, cholesterogenic genes, especially meiosis-activating sterol-producing enzyme cytochrome P450 lanosterol 14α-demethylase, display stage-specific expression patterns during spermatogenesis. Discrepancies in gene expression patterns suggest a complex temporal and cell-type specific regulation of sterol compounds during spermatogenesis, which also involves dynamic interactions between germ and Sertoli cells. The functional importance of sterol compounds in sperm production is further supported by the modulation of sterol composition in spermatozoal membranes during epididymal transit and in the female reproductive tract, which is a prerequisite for successful fertilization. However, the exact role of sterols in male reproduction is unknown. This review discusses sterol dynamics in sperm maturation and describes recent methodological advances that will help to illuminate the complexity of sperm formation and function. PMID:23093550

  14. Biofuels. Altered sterol composition renders yeast thermotolerant

    DEFF Research Database (Denmark)

    Caspeta, Luis; Chen, Yun; Ghiaci, Payam

    2014-01-01

    adaptive laboratory evolution to select yeast strains with improved growth and ethanol production at ≥40°C. Sequencing of the whole genome, genome-wide gene expression, and metabolic-flux analyses revealed a change in sterol composition, from ergosterol to fecosterol, caused by mutations in the C-5 sterol...... desaturase gene, and increased expression of genes involved in sterol biosynthesis. Additionally, large chromosome III rearrangements and mutations in genes associated with DNA damage and respiration were found, but contributed less to the thermotolerant phenotype....

  15. Biosynthesis and composition of sterols and sterol esters in the land snail Cepaea nemoralis (L.) (gastropoda, pulmonata, stylommatophora)

    NARCIS (Netherlands)

    Horst, D.J. van der; Voogt, P.A.

    1972-01-01

    1. 1. The biosynthesis and composition of sterols and sterol esters were studied in the land snail Cepaea nemoralis after injection of Na-1-14C-acetate. 2. 2. Free and esterified sterols appeared to be synthesized by the animals, whilst the specific radioactivity of the sterols from the esters was

  16. Biosynthesis and composition of sterols and sterol esters in the land snail Cepaea nemoralis (L.) (gastropoda, pulmonata, stylommatophora)

    NARCIS (Netherlands)

    Horst, D.J. van der; Voogt, P.A.

    1972-01-01

    1. 1. The biosynthesis and composition of sterols and sterol esters were studied in the land snail Cepaea nemoralis after injection of Na-1-14C-acetate. 2. 2. Free and esterified sterols appeared to be synthesized by the animals, whilst the specific radioactivity of the sterols from the esters was

  17. Sterol superlattice affects antioxidant potency and can be used to assess adverse effects of antioxidants.

    Science.gov (United States)

    Olsher, Michelle; Chong, Parkson Lee-Gau

    2008-11-01

    We have developed a fluorescence method to examine how membrane sterol lateral organization affects the potency of antioxidants, and used this information to evaluate possible adverse effects of lipid-soluble antioxidants seen in recent clinical studies. In the presence of an antioxidant, the lag time (tau) produced during free radical-induced sterol oxidation in lipid vesicles reflects the potency of the antioxidant. The ascorbic acid-induced tau value varies with sterol mol% in a biphasic manner, showing a minimum at the critical sterol mole fraction for maximal superlattice formation (C r), in ascorbic acid concentrations antioxidant potency. In contrast, the biphasic change in tau at C r was observed only at doses of ascorbyl palmitate antioxidant than its water-soluble counterpart as judged by the tau value, it can easily perturb sterol lateral organization by insertion into membrane bilayers, which could impose detrimental effects on cells. The threshold antioxidant concentration (C th) to abolish biphasic change in tau at C r may vary with antioxidant and could be used to assess potential adverse effects of other lipid-soluble antioxidants.

  18. Sterols from the Madagascar Sponge Fascaplysinopsis sp.

    Directory of Open Access Journals (Sweden)

    Yoel Kashman

    2010-12-01

    Full Text Available The sponge Fascaplysinopsis sp. (order Dictyoceratida, Family Thorectidae from the west coast of Madagascar (Indian Ocean is a particularly rich source of bioactive nitrogenous macrolides. The previous studies on this organism led to the suggestion that the latter should originate from associated microsymbionts. In order to evaluate the influence of microsymbionts on lipid content, 10 samples of Fascaplysinopsis sp. were investigated for their sterol composition. Contrary to the secondary metabolites, the sterol patterns established were qualitatively and quantitatively stable: 14 sterols with different unsaturated nuclei, D5, D7 and D5,7, were identified; the last ones being the main sterols of the investigated sponges. The chemotaxonomic significance of these results for the order Dictyoceratida is also discussed in the context of the literature. The conjugated diene system in D5,7 sterols is known to be unstable and easily photo-oxidized during storage and/or experiments to produce 5a,8a-epidioxy sterols. However, in this study, no 5a,8a-epidioxysterols (or only trace amounts were observed. Thus, it was supposed that photo-oxidation was avoided thanks to the natural antioxidants detected in Fascaplysinopsis sp. by both the DPPH and b-caroten bleaching assays.

  19. Sterols from the Madagascar sponge Fascaplysinopsis sp.

    Science.gov (United States)

    Aknin, Maurice; Gros, Emmanuelle; Vacelet, Jean; Kashman, Yoel; Gauvin-Bialecki, Anne

    2010-12-17

    The sponge Fascaplysinopsis sp. (order Dictyoceratida, Family Thorectidae) from the west coast of Madagascar (Indian Ocean) is a particularly rich source of bioactive nitrogenous macrolides. The previous studies on this organism led to the suggestion that the latter should originate from associated microsymbionts. In order to evaluate the influence of microsymbionts on lipid content, 10 samples of Fascaplysinopsis sp. were investigated for their sterol composition. Contrary to the secondary metabolites, the sterol patterns established were qualitatively and quantitatively stable: 14 sterols with different unsaturated nuclei, Δ(5), Δ(7) and Δ(5,7), were identified; the last ones being the main sterols of the investigated sponges. The chemotaxonomic significance of these results for the order Dictyoceratida is also discussed in the context of the literature. The conjugated diene system in Δ(5,7) sterols is known to be unstable and easily photo-oxidized during storage and/or experiments to produce 5α,8α-epidioxy sterols. However, in this study, no 5α,8α-epidioxysterols (or only trace amounts) were observed. Thus, it was supposed that photo-oxidation was avoided thanks to the natural antioxidants detected in Fascaplysinopsis sp. by both the DPPH and β-caroten bleaching assays.

  20. Plant sterols in food: No consensus in guidelines

    Energy Technology Data Exchange (ETDEWEB)

    Weingärtner, Oliver, E-mail: oweingartner@aol.com [Abteilung für Kardiologie, Klinikum Oldenburg, European Medical School Oldenburg-Groningen, Carl von Ossietzky Universität, Oldenburg (Germany); Baber, Ronny [Institut für Laboratoriumsmedizin, Klinische Chemie und Molekulare Diagnostik, Universität Leipzig, Leipzig (Germany); LIFE – Leipziger Forschungszentrum für Zivilisationserkrankungen, Universität Leipzig, Leipzig (Germany); Teupser, Daniel [Institut für Laboratoriumsmedizin, Ludwig-Maximilians-Universität, München (Germany)

    2014-04-11

    Highlights: • Plant sterols are used as food supplement to reduce serum cholesterol levels. • Reductions in serum cholesterol levels are achieved at the expense of increased plant sterol levels. • The potential atherogenicity of increased serum plant sterol levels is controversially debated. • This dispute is reflected by different guideline recommendations in regard to plant sterols. - Abstract: Plant sterols are supplemented in foods to reduce cardiovascular risk. Randomized controlled trials show 2 g of plant sterols a day reduce serum cholesterol by about 10%. This reduction in serum cholesterol levels is achieved at the expense of increased serum plant sterol levels. Findings in patients with phytosterolemia, in experimental studies and in clinical trials have lead to speculations that plant sterols might be atherogenic. In view of emerging safety issues the role of plant sterols in cardiovascular prevention has become controversial. This review reflects the ongoing controversial scientific debate and points out recent developments in guidelines of national and international societies.

  1. STARD4 Membrane Interactions and Sterol Binding.

    Science.gov (United States)

    Iaea, David B; Dikiy, Igor; Kiburu, Irene; Eliezer, David; Maxfield, Frederick R

    2015-08-01

    The steroidogenic acute regulatory protein-related lipid transfer (START) domain family is defined by a conserved 210-amino acid sequence that folds into an α/β helix-grip structure. Members of this protein family bind a variety of ligands, including cholesterol, phospholipids, sphingolipids, and bile acids, with putative roles in nonvesicular lipid transport, metabolism, and cell signaling. Among the soluble START proteins, STARD4 is expressed in most tissues and has previously been shown to transfer sterol, but the molecular mechanisms of membrane interaction and sterol binding remain unclear. In this work, we use biochemical techniques to characterize regions of STARD4 and determine their role in membrane interaction and sterol binding. Our results show that STARD4 interacts with anionic membranes through a surface-exposed basic patch and that introducing a mutation (L124D) into the Omega-1 (Ω1) loop, which covers the sterol binding pocket, attenuates sterol transfer activity. To gain insight into the attenuating mechanism of the L124D mutation, we conducted structural and biophysical studies of wild-type and L124D STARD4. These studies show that the L124D mutation reduces the conformational flexibility of the protein, resulting in a diminished level of membrane interaction and sterol transfer. These studies also reveal that the C-terminal α-helix, and not the Ω1 loop, partitions into the membrane bilayer. On the basis of these observations, we propose a model of STARD4 membrane interaction and sterol binding and release that requires dynamic movement of both the Ω1 loop and membrane insertion of the C-terminal α-helix.

  2. Involvement of the Phospholipid Sterol Acyltransferase1 in Plant Sterol Homeostasis and Leaf Senescence1[W

    Science.gov (United States)

    Bouvier-Navé, Pierrette; Berna, Anne; Noiriel, Alexandre; Compagnon, Vincent; Carlsson, Anders S.; Banas, Antoni; Stymne, Sten; Schaller, Hubert

    2010-01-01

    Genes encoding sterol ester-forming enzymes were recently identified in the Arabidopsis (Arabidopsis thaliana) genome. One belongs to a family of six members presenting homologies with the mammalian Lecithin Cholesterol Acyltransferases. The other one belongs to the superfamily of Membrane-Bound O-Acyltransferases. The physiological functions of these genes, Phospholipid Sterol Acyltransferase1 (PSAT1) and Acyl-CoA Sterol Acyltransferase1 (ASAT1), respectively, were investigated using Arabidopsis mutants. Sterol ester content decreased in leaves of all mutants and was strongly reduced in seeds from plants carrying a PSAT1-deficient mutation. The amount of sterol esters in flowers was very close to that of the wild type for all lines studied. This indicated further functional redundancy of sterol acylation in Arabidopsis. We performed feeding experiments in which we supplied sterol precursors to psat1-1, psat1-2, and asat1-1 mutants. This triggered the accumulation of sterol esters (stored in cytosolic lipid droplets) in the wild type and the asat1-1 lines but not in the psat1-1 and psat1-2 lines, indicating a major contribution of the PSAT1 in maintaining free sterol homeostasis in plant cell membranes. A clear biological effect associated with the lack of sterol ester formation in the psat1-1 and psat1-2 mutants was an early leaf senescence phenotype. Double mutants lacking PSAT1 and ASAT1 had identical phenotypes to psat1 mutants. The results presented here suggest that PSAT1 plays a role in lipid catabolism as part of the intracellular processes at play in the maintenance of leaf viability during developmental aging. PMID:19923239

  3. High lipid order of Arabidopsis cell-plate membranes mediated by sterol and DYNAMIN-RELATED PROTEIN1A function.

    Science.gov (United States)

    Frescatada-Rosa, Márcia; Stanislas, Thomas; Backues, Steven K; Reichardt, Ilka; Men, Shuzhen; Boutté, Yohann; Jürgens, Gerd; Moritz, Thomas; Bednarek, Sebastian Y; Grebe, Markus

    2014-12-01

    Membranes of eukaryotic cells contain high lipid-order sterol-rich domains that are thought to mediate temporal and spatial organization of cellular processes. Sterols are crucial for execution of cytokinesis, the last stage of cell division, in diverse eukaryotes. The cell plate of higher-plant cells is the membrane structure that separates daughter cells during somatic cytokinesis. Cell-plate formation in Arabidopsis relies on sterol- and DYNAMIN-RELATED PROTEIN1A (DRP1A)-dependent endocytosis. However, functional relationships between lipid membrane order or lipid packing and endocytic machinery components during eukaryotic cytokinesis have not been elucidated. Using ratiometric live imaging of lipid order-sensitive fluorescent probes, we show that the cell plate of Arabidopsis thaliana represents a dynamic, high lipid-order membrane domain. The cell-plate lipid order was found to be sensitive to pharmacological and genetic alterations of sterol composition. Sterols co-localize with DRP1A at the cell plate, and DRP1A accumulates in detergent-resistant membrane fractions. Modifications of sterol concentration or composition reduce cell-plate membrane order and affect DRP1A localization. Strikingly, DRP1A function itself is essential for high lipid order at the cell plate. Our findings provide evidence that the cell plate represents a high lipid-order domain, and pave the way to explore potential feedback between lipid order and function of dynamin-related proteins during cytokinesis.

  4. Quantification of sterol lipids in plants by quadrupole time-of-flight mass spectrometry

    OpenAIRE

    Wewer, Vera; Dombrink, Isabel; vom Dorp, Katharina; Dörmann, Peter

    2011-01-01

    Glycerolipids, sphingolipids, and sterol lipids constitute the major lipid classes in plants. Sterol lipids are composed of free and conjugated sterols, i.e., sterol esters, sterol glycosides, and acylated sterol glycosides. Sterol lipids play crucial roles during adaption to abiotic stresses and plant-pathogen interactions. Presently, no comprehensive method for sterol lipid quantification in plants is available. We used nanospray ionization quadrupole-time-of-flight mass spectrometry (Q-TOF...

  5. Quantitative and qualitative analysis of sterols/sterolins and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-06-03

    Jun 3, 2008 ... Quantitative and qualitative analysis of sterols/sterolins ... method was developed to identify and quantify sterols (especially β-sitosterol) in chloroform extracts of ... Studies with phytosterols, especially β-sitosterol, have.

  6. Enzyme mechanisms for sterol C-methylations.

    Science.gov (United States)

    Nes, W David

    2003-09-01

    The mechanisms by which sterol methyl transferases (SMT) transform olefins into structurally different C-methylated products are complex, prompting over 50 years of intense research. Recent enzymological studies, together with the latest discoveries in the fossil record, functional analyses and gene cloning, establish new insights into the enzymatic mechanisms of sterol C-methylation and form a basis for understanding regulation and evolution of the sterol pathway. These studies suggest that SMTs, originated shortly after life appeared on planet earth. SMTs, including those which ultimately give rise to 24 alpha- and 24 beta-alkyl sterols, align the si(beta)-face pi-electrons of the Delta(24)-double bond with the S-methyl group of AdoMet relative to a set of deprotonation bases in the active site. From the orientation of the conformationally flexible side chain in the SMT Michaelis complex, it has been found that either a single product is formed or cationic intermediates are partitioned into multiple olefins. The product structure and stereochemistry of SMT action is phylogenetically distinct and physiologically significant. SMTs control phytosterol homeostasis and their activity is subject to feedback regulation by specific sterol inserts in the membrane. A unified conceptual framework has been formulated in the steric-electric plug model that posits SMT substrate acceptability on the generation of single or double 24-alkylated side chains, which is the basis for binding order, stereospecificity and product diversity in this class of AdoMet-dependent methyl transferase enzymes. The focus of this review is the mechanism of the C-methylation process which, as discussed, can be altered by point mutations in the enzyme to direct the shape of sterol structure to optimize function.

  7. Biological removal of phyto-sterols in pulp mill effluents.

    Science.gov (United States)

    Mahmood-Khan, Zahid; Hall, Eric R

    2013-12-15

    Phyto-sterols and extractives found in pulp mill effluents are suspected to cause endocrine abnormalities in receiving water fish. The control of sterols in pulp mill effluents through biological secondary wastewater treatment was studied using two lab-scale bioreactor systems. After achieving a stable performance, both bioreactor systems successfully removed (>90%) sterols and the estimated biodegradation was up to 80%. Reactor 1 system operating at 6.7 ± 0.2 pH effectively treated pulp mill effluent sterols spiked up to 4500 μg/L in 11 h HRT and 11 day SRT. However, Reactor 2 system operating at 7.6 ± 0.2 pH performed relatively poorly. Retention time reductions beyond critical values deteriorated the performance of treatment systems and quickly reduced the sterols biodegradation. The biodegradation loss was indicated by mixed liquor sterols content that started increasing. This biodegradation loss was compensated by the increased role of bio-adsorption and the overall sterols removal remained relatively high. Hence, a relatively small (20-30%) loss in the overall sterols removal efficiency did not fully reflect the associated major (60-70%) loss in the sterols biodegradation because the amount of sterols accumulated in the sludge due to adsorption increased so the estimate of sterols removal through adsorption increased from 30-40% to 70-80% keeping the overall sterols removal still high.

  8. Deficiency in the Lipid Exporter ABCA1 Impairs Retrograde Sterol Movement and Disrupts Sterol Sensing at the Endoplasmic Reticulum.

    Science.gov (United States)

    Yamauchi, Yoshio; Iwamoto, Noriyuki; Rogers, Maximillian A; Abe-Dohmae, Sumiko; Fujimoto, Toyoshi; Chang, Catherine C Y; Ishigami, Masato; Kishimoto, Takuma; Kobayashi, Toshihide; Ueda, Kazumitsu; Furukawa, Koichi; Chang, Ta-Yuan; Yokoyama, Shinji

    2015-09-25

    Cellular cholesterol homeostasis involves sterol sensing at the endoplasmic reticulum (ER) and sterol export from the plasma membrane (PM). Sterol sensing at the ER requires efficient sterol delivery from the PM; however, the macromolecules that facilitate retrograde sterol transport at the PM have not been identified. ATP-binding cassette transporter A1 (ABCA1) mediates cholesterol and phospholipid export to apolipoprotein A-I for the assembly of high density lipoprotein (HDL). Mutations in ABCA1 cause Tangier disease, a familial HDL deficiency. Several lines of clinical and experimental evidence suggest a second function of ABCA1 in cellular cholesterol homeostasis in addition to mediating cholesterol efflux. Here, we report the unexpected finding that ABCA1 also plays a key role in facilitating retrograde sterol transport from the PM to the ER for sterol sensing. Deficiency in ABCA1 delays sterol esterification at the ER and activates the SREBP-2 cleavage pathway. The intrinsic ATPase activity in ABCA1 is required to facilitate retrograde sterol transport. ABCA1 deficiency causes alternation of PM composition and hampers a clathrin-independent endocytic activity that is required for ER sterol sensing. Our finding identifies ABCA1 as a key macromolecule facilitating bidirectional sterol movement at the PM and shows that ABCA1 controls retrograde sterol transport by modulating a certain clathrin-independent endocytic process.

  9. Nuclear hormone receptors put immunity on sterols.

    Science.gov (United States)

    Santori, Fabio R

    2015-10-01

    Nuclear hormone receptors (NHRs) are transcription factors regulated by small molecules. The functions of NHRs range from development of primary and secondary lymphoid organs, to regulation of differentiation and function of DCs, macrophages and T cells. The human genome has 48 classic (hormone and vitamin receptors) and nonclassic (all others) NHRs; 17 nonclassic receptors are orphans, meaning that the endogenous ligand is unknown. Understanding the function of orphan NHRs requires the identification of their natural ligands. The mevalonate pathway, including its sterol and nonsterol intermediates and derivatives, is a source of ligands for many classic and nonclassic NHRs. For example, cholesterol biosynthetic intermediates (CBIs) are natural ligands for RORγ/γt. CBIs are universal endogenous metabolites in mammalian cells, and to study NHRs that bind CBIs requires ligand-free reporters system in sterol auxotroph cells. Furthermore, RORγ/γt shows broad specificity to sterol lipids, suggesting that RORγ/γt is either a general sterol sensor or specificity is defined by an abundant endogenous ligand. Unlike other NHRs, which regulate specific metabolic pathways, there is no connection between the genetic programs induced by RORγ/γt and ligand biosynthesis. In this review, we summarize the roles of nonclassic NHRs and their potential ligands in the immune system.

  10. Two New Sterols from Bolbostemma paniculatum

    Institute of Scientific and Technical Information of China (English)

    Wen Yong LIU; Wei Dong ZHANG; Hai Sheng CHEN; Zheng Bing GU; Ting Zhao LI; Wan Sheng CHEN

    2003-01-01

    Two new sterols were isolated from bulbs of Bolbostemma paniculatum (Maxim.)Franquet. Their structures were elucidated as stigmasta-7, 22, 25-triene-3-O-nonadecanoic acidester (1) and stigmasta-7, 22, 25-triene-3-O-β-D- (6'-palmitoyl) glucopyranoside (2) by chemicaland spectroscopic methods.

  11. Distribution of sterols in the fungi. I - Fungal spores

    Science.gov (United States)

    Weete, J. D.; Laseter, J. L.

    1974-01-01

    Mass spectrometry was used to examine freely extractable sterols from spores of several species of fungi. Ergosterol was the most common sterol produced by any individual species, but it was completely absent from two species belonging to apparently distantly related groups of fungi: the aquatic Phycomycetes and the rust fungi. This fact could have taxonomic or phylogenetic implications. The use of glass capillary columns in the resolution of the sterols is shown to eliminate some of the difficulty inherent in this process.

  12. Distribution of sterols in the fungi. I - Fungal spores

    Science.gov (United States)

    Weete, J. D.; Laseter, J. L.

    1974-01-01

    Mass spectrometry was used to examine freely extractable sterols from spores of several species of fungi. Ergosterol was the most common sterol produced by any individual species, but it was completely absent from two species belonging to apparently distantly related groups of fungi: the aquatic Phycomycetes and the rust fungi. This fact could have taxonomic or phylogenetic implications. The use of glass capillary columns in the resolution of the sterols is shown to eliminate some of the difficulty inherent in this process.

  13. [Plant sterols, cholesterol precursors and oxysterols: small amounts, big effects].

    Science.gov (United States)

    Olkkonen, Vesa M; Gylling, Helena; Ikonen, Elina

    2015-01-01

    Noncholesterol sterols are present in the body in very low concentrations compared with cholesterol. Minor structural changes in sterols give them completely individual biological activities. Steroid hormones are the best known example of this. The knowledge of other relatives of cholesterol, particularly plant sterols, cholesterol precursors and oxysterols, their properties, physiological effects, significance in disease processes and diagnostic applications has recently undergone a rapid increase.

  14. Non-cholesterol sterols and cholesterol metabolism in sitosterolemia.

    Science.gov (United States)

    Othman, Rgia A; Myrie, Semone B; Jones, Peter J H

    2013-12-01

    Sitosterolemia (STSL) is a rare autosomal recessive disease, manifested by extremely elevated plant sterols (PS) in plasma and tissue, leading to xanthoma and premature atherosclerotic disease. Therapeutic approaches include limiting PS intake, interrupting enterohepatic circulation of bile acid using bile acid binding resins such as cholestyramine, and/or ileal bypass, and inhibiting intestinal sterol absorption by ezetimibe (EZE). The objective of this review is to evaluate sterol metabolism in STSL and the impact of the currently available treatments on sterol trafficking in this disease. The role of PS in initiation of xanthomas and premature atherosclerosis is also discussed. Blocking sterols absorption with EZE has revolutionized STSL patient treatment as it reduces circulating levels of non-cholesterol sterols in STSL. However, none of the available treatments including EZE have normalized plasma PS concentrations. Future studies are needed to: (i) explore where cholesterol and non-cholesterol sterols accumulate, (ii) assess to what extent these sterols in tissues can be mobilized after blocking their absorption, and (iii) define the factors governing sterol flux.

  15. Cholesterol homeostasis: How do cells sense sterol excess?

    Science.gov (United States)

    Howe, Vicky; Sharpe, Laura J; Alexopoulos, Stephanie J; Kunze, Sarah V; Chua, Ngee Kiat; Li, Dianfan; Brown, Andrew J

    2016-09-01

    Cholesterol is vital in mammals, but toxic in excess. Consequently, elaborate molecular mechanisms have evolved to maintain this sterol within narrow limits. How cells sense excess cholesterol is an intriguing area of research. Cells sense cholesterol, and other related sterols such as oxysterols or cholesterol synthesis intermediates, and respond to changing levels through several elegant mechanisms of feedback regulation. Cholesterol sensing involves both direct binding of sterols to the homeostatic machinery located in the endoplasmic reticulum (ER), and indirect effects elicited by sterol-dependent alteration of the physical properties of membranes. Here, we examine the mechanisms employed by cells to maintain cholesterol homeostasis.

  16. Involvement of heme biosynthesis in control of sterol uptake by Saccharomyces cerevisiae.

    OpenAIRE

    Lewis, T A; Taylor, F R; Parks, L W

    1985-01-01

    Wild-type Saccharomyces cerevisiae do not accumulate exogenous sterols under aerobic conditions, and a mutant allele conferring sterol auxotrophy (erg7) could be isolated only in strains with a heme deficiency. delta-Aminolevulinic acid (ALA) fed to a hem1 (ALA synthetase-) erg7 (2,3-oxidosqualene cyclase-) sterol-auxotrophic strain of S. cerevisiae inhibited sterol uptake, and growth was negatively affected when intracellular sterol was depleted. The inhibition of sterol uptake (and growth o...

  17. SUPLEMENTASI STEROL LEMBAGA GANDUM (Triticum sp. PADA MARGARIN (Supplementation of Margarine with Wheat Germ Sterol

    Directory of Open Access Journals (Sweden)

    Sri Anna Marliyati1*

    2010-06-01

    Full Text Available Margarine is a water in oil (w/o emulsion product which is widely used for household cooking and baking industry. Consuming of margarine, which contains trans fatty acid may cause health problem due to the increase of LDL cholesterol. Since margarine is also a good carrier of phytosterol which prevent the absorption of cholesterol, there is a possibility to formulate a healthier margarine. In this research formulation and characteristics of products was investigated. The research work consisted of two steps: (1 supplementation of wheat germ sterol into margarine (two methods and (2 analysis of physical, chemical characteristics and hedonic score. Parameters of physical characteristics were melting point and emulsion stability, whereas chemical characteristics were water and oil contents. The hedonic test was carried out based on product’s color, odor, taste, texture, and spreadability. Results showed that method II of supplementation produced better margarine than method I, in which the concentration of sterol in the margarine was higher with a melting point similar to that of control, better emulsion stability, and higher hedonic score. Supplementation process was carried out by mixing sterol into fat phase melted at 50 0C, followed by mixing with aqueous phase at 4 0C. Sterol used for method II was extracted using mixed solvent of hexane and ethanol at the ratio of 1:2 (v/v, which was resulted from previous experimentation.

  18. Two New Sterols from Amoora yunnanensis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two new sterols, 3β,7α,16β-trihydroxy-stigmast-5,22-diene 1, 3β,7α,16β-trihydroxy-stigmast-5-ene 2, were isolated together with two known ergosterols, ergosta-5,24(28)-diene-3β,7α-diol, ergosta-5,24(28)-diene-3β,7α,16β-triol from the bark of Amoora yunnanensis (H. L. Li) C. Y. Wu. Their structures were deduced on the basis of spectral data.

  19. Sterols from the Fungus Catathelasma imperiale

    Institute of Scientific and Technical Information of China (English)

    YANG, Sheng-Ping; XU, Jun; YUE, Jian-Min

    2003-01-01

    Eight ergostane-type sterols and three their derivatives (one mono-linoleate and two mono-glucosides) were isolated from the ethyl acetate soluble fraction of the fungus Catathelasma imperiale. Two of them are novel compounds, namely 22E, 24R-ergosta-7,22-diene-3β, 5α-diol-6β-linoleate (1) and 22E, 24R-ergosta-7,22-diene-3β,5β,6α-triol (5) with an uncommon cisfused A/B ring. Structures of these compounds were demonstrated on the basis of their chemical evidences and spectroscopic methods, especially 2D NMR techniques.

  20. A reappraisal of the mechanism by which plant sterols promote neutral sterol loss in mice.

    Directory of Open Access Journals (Sweden)

    Gemma Brufau

    Full Text Available UNLABELLED: Dietary plant sterols (PS reduce serum total and LDL-cholesterol in hyperlipidemic animal models and in humans. This hypocholesterolemic effect is generally ascribed to inhibition of cholesterol absorption. However, whether this effect fully explains the reported strong induction of neutral sterol excretion upon plant sterol feeding is not known. Recent data demonstrate that the intestine directly mediates plasma cholesterol excretion into feces, i.e., without involvement of the hepato-biliary route. OBJECTIVE: Aim of this study was to determine whether stimulation of fecal neutral sterol loss during PS feeding is (partly explained by increased intestinal cholesterol excretion and to assess the role of the cholesterol transporter Abcg5/Abcg8 herein. METHODS AND RESULTS: Wild-type mice were fed a control diet or diets enriched with increasing amounts of PS (1%, 2%, 4% or 8%, wt/wt for two weeks. In addition, Abcg5(-/- mice were fed either control or 8% PS diet. PS feeding resulted in a dose-dependent decrease of fractional cholesterol absorption (∼2-7-fold reduction in wild-type mice and ∼80% reduction in Abcg5(-/- mice. Furthermore, PS feeding led to a strong, dose-independent induction of neutral sterol excretion (3.4-fold in wild-types and 2.7-fold in Abcg5(-/- mice without changes in biliary cholesterol secretion. It was calculated that PS feeding stimulated intestinal cholesterol excretion by ∼500% in wild-type mice and by ∼250% in Abcg5(-/-. CONCLUSIONS: Our data indicate that in mice the cholesterol-lowering effects of PS are to a large extent attributable to stimulation of intestinal, non-bile derived, cholesterol excretion. The Abcg5/Abcg8 heterodimer is involved in facilitating this PS-induced flux of cholesterol.

  1. Reduced fecal sterol excretion in subjects with familial hypoalphalipoproteinemia

    NARCIS (Netherlands)

    El Harchaoui, Karim; Franssen, Remco; Hovingh, G. Kees; Bisoendial, Radjesh J.; Stellaard, Frans; Kuipers, Folkert; Kastelein, John J. P.; Kuivenhoven, Jan Albert; Stroes, Erik S. G.; Groen, Albert K.

    2009-01-01

    BACKGROUND: Fecal bile acid and neutral sterol excretion are the obligate endpoints of the reverse cholesterol transport pathway (RCT). In studies in mice, no evidence was found for a relation between HDL-cholesterol (HDL-c) levels and fecal sterol excretion. In this study, we have evaluated this re

  2. Detailed sterol compositions of two pathogenic rust fungi.

    Science.gov (United States)

    Giner, José-Luis; Zhao, Hui

    2004-08-01

    Teliospores of cedar-apple rust Gymnosporangium juniperi-virginianae were collected from the eastern red cedar Juniperus virginiana, and aeciospores of quince rust G. clavipes were collected from the fruit of English hawthorn Crataegus laevigata. The sterol fractions were separated by HPLC, and their identities were determined by 600 MHz 1H NMR. Twenty-six sterols were isolated from G. juniperi-virginianae and 18 sterols were isolated from G. clavipes. The principal sterol of both fungi was (Z)-stigmasta-7,24(28)-dien-3beta-ol. Other major sterols were (24S)-ergost-7-en-3beta-ol, (24S)-stigmast-7-en-3beta-ol, and (24S)-stigmasta-5,7-dien-3beta-ol. The sterols of the hosts were found to be very different from those of the fungi. The 24-alkyl sterols of the fungi had the 24alpha-configuration, whereas those of the hosts had the 24beta-configuration. Similarities to the sterol composition of the AIDS pneumonia fungus Pneumocystis carinii are discussed.

  3. Composition of plant sterols and stanols in supplemented food products

    Science.gov (United States)

    All fruits, vegetables, grains and other plant materials contain small amounts of plant sterols, which are essential for the function of the biological membranes in living cells. The average human consumption of plant sterols has been estimated to be about 150-350 mg/day and trace amounts of stanol...

  4. STEROLS AS BIOMARKERS IN GYMNODINIUM BREVE DISTRIBUTION IN DINOFLAGELLATES

    Science.gov (United States)

    The sterol composition of marine microalgae has been shown to be a chemotaxonomic property potentially of value in distinguishing members of different algal classes. For example, members of the class Dinophyceae display sterol compositions ranging from as few as two (cholesterol ...

  5. Sterol Ring System Oxidation Pattern in Marine Sponges

    Directory of Open Access Journals (Sweden)

    S. Ramakrishna Rao

    2005-06-01

    Full Text Available Abstract: The marine sponges (Porifera are a unique group of sedentary organisms from which several novel natural products are reported, many of which have useful biological activities. In producing unusual sterols, they occupy a preeminent position among the various groups of organisms. The polar sterols of sponges reported as at the end of the year 2002 number about 250; their ring structure changing a hundred times. The oxidation pattern in the sterol ring system, from the point of view of biogenesis seems to be mainly of four types. Each sponge species is able to produce sterols fitting into one of the four main biogenetic pathways viz., (i 3β-hydroxy-Δ5-sterol pathway, (ii 3β-hydroxy-Δ7-sterol pathway, (iii 3β-hydroxy-Δ5,7-sterol pathway, and (iv 3α-hydroxy sterol pathway.

  6. Δ24-Sterol Methyltransferase Plays an Important Role in the Growth and Development of Sporothrix schenckii and Sporothrix brasiliensis

    Science.gov (United States)

    Borba-Santos, Luana P.; Visbal, Gonzalo; Gagini, Thalita; Rodrigues, Anderson M.; de Camargo, Zoilo P.; Lopes-Bezerra, Leila M.; Ishida, Kelly; de Souza, Wanderley; Rozental, Sonia

    2016-01-01

    Inhibition of Δ24-sterol methyltransferase (24-SMT) in Sporothrix schenckii sensu stricto and Sporothrix brasiliensis was investigated in vitro. The effects on fungal growth and sterol composition of the 24-SMT inhibitor 22-hydrazone-imidazolin-2-yl-chol-5-ene-3β-ol (H3) were compared to those of itraconazole. MIC and MFC analysis showed that H3 was more effective than itraconazole against both species in both their filamentous and yeast forms. H3 showed fungistatic activity in a time-kill assay, with inhibitory activity stronger than that of itraconazole. GC analysis of cell sterol composition showed that sterols present in control cells (ergosterol and precursors) were completely replaced by 14α-methylated sterols after H3 exposure. Itraconazole only partially inhibited ergosterol synthesis but completely arrested synthesis of other sterols found in control cells, promoting accumulation of nine 14α-methyl sterols. Based on these results, we propose a schematic model of sterol biosynthesis pathways in S. schenckii and S. brasiliensis. Effects on cell morphology due to 24-SMT inhibition by H3 as analyzed by SEM and TEM included irregular cell shape, reduced cytoplasmic electron-density, and reduced thickness of the microfibrillar cell wall layer. Moreover, 24-SMT inhibition by H3 promoted mitochondrial disturbance, as demonstrated by alterations in MitoTracker® Red CMXRos fluorescence intensity evaluated by flow cytometry. When used in conjunction with itraconazole, H3 enhanced the effectiveness of itraconazole against all tested strains, reducing at least half (or more) the MIC values of itraconazole. In addition, cytotoxicity assays revealed that H3 was more selective toward these fungi than was itraconazole. Thus, 24-SMT inhibition by H3 was an effective antifungal strategy against S. schenckii and S. brasiliensis. Inhibition of the methylation reaction catalyzed by 24-SMT has a strong antiproliferative effect via disruption of ergosterol homeostasis

  7. Δ(24)-Sterol Methyltransferase Plays an Important Role in the Growth and Development of Sporothrix schenckii and Sporothrix brasiliensis.

    Science.gov (United States)

    Borba-Santos, Luana P; Visbal, Gonzalo; Gagini, Thalita; Rodrigues, Anderson M; de Camargo, Zoilo P; Lopes-Bezerra, Leila M; Ishida, Kelly; de Souza, Wanderley; Rozental, Sonia

    2016-01-01

    Inhibition of Δ(24)-sterol methyltransferase (24-SMT) in Sporothrix schenckii sensu stricto and Sporothrix brasiliensis was investigated in vitro. The effects on fungal growth and sterol composition of the 24-SMT inhibitor 22-hydrazone-imidazolin-2-yl-chol-5-ene-3β-ol (H3) were compared to those of itraconazole. MIC and MFC analysis showed that H3 was more effective than itraconazole against both species in both their filamentous and yeast forms. H3 showed fungistatic activity in a time-kill assay, with inhibitory activity stronger than that of itraconazole. GC analysis of cell sterol composition showed that sterols present in control cells (ergosterol and precursors) were completely replaced by 14α-methylated sterols after H3 exposure. Itraconazole only partially inhibited ergosterol synthesis but completely arrested synthesis of other sterols found in control cells, promoting accumulation of nine 14α-methyl sterols. Based on these results, we propose a schematic model of sterol biosynthesis pathways in S. schenckii and S. brasiliensis. Effects on cell morphology due to 24-SMT inhibition by H3 as analyzed by SEM and TEM included irregular cell shape, reduced cytoplasmic electron-density, and reduced thickness of the microfibrillar cell wall layer. Moreover, 24-SMT inhibition by H3 promoted mitochondrial disturbance, as demonstrated by alterations in MitoTracker(®) Red CMXRos fluorescence intensity evaluated by flow cytometry. When used in conjunction with itraconazole, H3 enhanced the effectiveness of itraconazole against all tested strains, reducing at least half (or more) the MIC values of itraconazole. In addition, cytotoxicity assays revealed that H3 was more selective toward these fungi than was itraconazole. Thus, 24-SMT inhibition by H3 was an effective antifungal strategy against S. schenckii and S. brasiliensis. Inhibition of the methylation reaction catalyzed by 24-SMT has a strong antiproliferative effect via disruption of ergosterol homeostasis

  8. ∆24-sterol methyltransferase plays an important role in the growth and development of Sporothrix schenckii and Sporothrix brasiliensis

    Directory of Open Access Journals (Sweden)

    Luana Pereira Borba-Santos

    2016-03-01

    Full Text Available Inhibition of ∆24-sterol methyltransferase (24-SMT in Sporothrix schenckii sensu stricto and Sporothrix brasiliensis was investigated in vitro. The effects on fungal growth and sterol composition of the 24-SMT inhibitor 22-hydrazone-imidazolin-2-yl-chol-5-ene-3-ol (H3 were compared to those of itraconazole. MIC and MFC analysis showed that H3 was more effective than itraconazole against both species in both their filamentous and yeast forms. H3 showed fungistatic activity in a time-kill assay, with inhibitory activity stronger than that of itraconazole. GC analysis of cell sterol composition showed that sterols present in control cells (ergosterol and precursors were completely replaced by 14-methylated sterols after H3 exposure. Itraconazole only partially inhibited ergosterol synthesis but completely arrested synthesis of other sterols found in control cells, promoting accumulation of nine 14-methyl sterols. Based on these results, we propose a schematic model of sterol biosynthesis pathways in S. schenckii and S. brasiliensis. Effects on cell morphology due to 24-SMT inhibition by H3 as analyzed by SEM and TEM included irregular cell shape, reduced cytoplasmic electron-density, and reduced thickness of the microfibrillar cell wall layer. Moreover, 24-SMT inhibition by H3 promoted mitochondrial disturbance, as demonstrated by alterations in MitoTracker® Red CMXRos fluorescence intensity evaluated by flow cytometry. When used in conjunction with itraconazole, H3 enhanced the effectiveness of itraconazole against all tested strains, reducing at least half (or more the MIC values of itraconazole. In addition, cytotoxicity assays revealed that H3 was more selective towards these fungi than was itraconazole. Thus, 24-SMT inhibition by H3 was an effective antifungal strategy against S. schenckii and S. brasiliensis. Inhibition of the methylation reaction catalyzed by 24-SMT has a strong antiproliferative effect via disruption of

  9. Origin assessment of EV olive oils by esterified sterols analysis.

    Science.gov (United States)

    Giacalone, Rosa; Giuliano, Salvatore; Gulotta, Eleonora; Monfreda, Maria; Presti, Giovanni

    2015-12-01

    In this study extra virgin olive oils of Italian and non-Italian origin (from Spain, Tunisia and blends of EU origin) were differentiated by GC-FID analysis of sterols and esterified sterols followed by chemometric tools. PCA allowed to highlight the high significance of esterified sterols to characterise extra virgin olive oils in relation to their origin. SIMCA provided a sensitivity and specificity of 94.39% and 91.59% respectively; furthermore, an external set of 54 extra virgin olive oils bearing a designation of Italian origin on the labelling was tested by SIMCA. Prediction results were also compared with organoleptic assessment. Finally, the poor correlation found between ethylesters and esterified sterols allowed to hazard the guess, worthy of further investigations, that esterified sterols may prove to be promising in studies of geographical discrimination: indeed they appear to be independent of those factors causing the formation of ethyl esters and related to olive oil production.

  10. Sterols of Pneumocystis carinii hominis organisms isolated from human lungs

    DEFF Research Database (Denmark)

    Kaneshiro, E S; Amit, Z; Chandra, Jan Suresh

    1999-01-01

    The opportunistic pathogen Pneumocystis carinii causes pneumonia (P. carinii pneumonia, or PCP) in immunocompromised individuals such as AIDS patients. Rat-derived P. carinii carinii organisms have distinct sterols which are not synthesized by mammals and not found in other microbes infecting...... mammalian lungs. The dominant sterol present in the organism is cholesterol (which is believed to be scavenged from the host), but other sterols in P. carinii carinii have an alkyl group at C-24 of the sterol side chain (C(28) and C(29) 24-alkylsterols) and a double bond at C-7 of the nucleus. Recently...... in conjunction with analyses of chemically synthesized authentic standards. The sterol composition of isolated P. carinii hominis organisms has yet to be reported. If P. carinii from animal models is to be used for identifying potential drug targets and for developing chemotherapeutic approaches to clear human...

  11. Sterols and Fatty Acids of the Harmful Dinoflagellate Cochlodinium polykrikoides.

    Science.gov (United States)

    Giner, José-Luis; Ceballos, Harriette; Tang, Ying-Zhong; Gobler, Christopher J

    2016-02-01

    Sterol and fatty acid compositions were determined for Cochlodinium polykrikoides, a toxic, bloom-forming dinoflagellate of global significance. The major sterols were dinosterol (40% of total sterols), dihydrodinosterol (32%), and the rare 4α-methyl Δ(8(14)) sterol, amphisterol (23%). A minor sterol, 4α-methylergost-24(28)-enol was also detected (5.0%). The fatty acids had a high proportion of PUFAs (47%), consisting mainly of EPA (20%) and the relatively uncommon octadecapentaenoic acid (18 : 5, 22%). While unlikely to be responsible for toxicity to fish, these lipids may contribute to the deleterious effects of this alga to invertebrates. Copyright © 2016 Verlag Helvetica Chimica Acta AG, Zürich.

  12. Diversity of Sterol Composition in Tunisian Pistacia lentiscus Seed Oil.

    Science.gov (United States)

    Mezni, Faten; Labidi, Arbia; Khouja, Mohamed Larbi; Martine, Lucy; Berdeaux, Olivier; Khaldi, Abdelhamid

    2016-05-01

    Pistacia lentiscus L. seed oil is used in some Mediterranean forest area for culinary and medicinal purposes. In this study, we aim to examine, for the first time, the effect of growing area on sterol content of Pistacia lentiscus seed oil. Fruits were harvested from 13 different sites located in northern and central Tunisia. Gas chromatography-flame-ionization detection (GC-FID) was used to quantify sterols and gas chromatography/mass spectrometry (GC/MS) was used to identify them. The major sterol identified was β-sitosterol with a value ranging from 854.12 to 1224.09 mg/kg of oil, thus making up more than 54% of the total sterols. The other two main sterols were cycloartenol (11%) and 24-methylene-cycloartenol (5%). Statistical results revealed that growing location significantly (P < 0.001) affected phytosterol levels in these oils.

  13. Profiling and Metabolism of Sterols in the Weaver Ant Genus Oecophylla.

    Science.gov (United States)

    Vidkjær, Nanna H; Jensen, Karl-Martin V; Gislum, René; Fomsgaard, Inge S

    2016-01-01

    Sterols are essential to insects because they are vital for many biochemical processes, nevertheless insects cannot synthesize sterols but have to acquire them through their diet. Studies of sterols in ants are sparse and here the sterols of the weaver ant genus Oecophylla are identified for the first time. The sterol profile and the dietary sterols provided to a laboratory Oecophylla longinoda colony were analyzed. Most sterols originated from the diet, except one, which was probably formed via dealkylation in the ants and two sterols of fungal origin, which likely originate from hitherto unidentified endosymbionts responsible for supplying these two compounds. The sterol profile of a wild Oecophylla smaragdina colony was also investigated. Remarkable qualitative similarities were established between the two species despite the differences in diet, species, and origin. This may reflect a common sterol need/aversion in the weaver ants. Additionally, each individual caste of both species displayed unique sterol profiles.

  14. ATP-binding cassette transporters and sterol O-acyltransferases interact at membrane microdomains to modulate sterol uptake and esterification.

    Science.gov (United States)

    Gulati, Sonia; Balderes, Dina; Kim, Christine; Guo, Zhongmin A; Wilcox, Lisa; Area-Gomez, Estela; Snider, Jamie; Wolinski, Heimo; Stagljar, Igor; Granato, Juliana T; Ruggles, Kelly V; DeGiorgis, Joseph A; Kohlwein, Sepp D; Schon, Eric A; Sturley, Stephen L

    2015-11-01

    A key component of eukaryotic lipid homeostasis is the esterification of sterols with fatty acids by sterol O-acyltransferases (SOATs). The esterification reactions are allosterically activated by their sterol substrates, the majority of which accumulate at the plasma membrane. We demonstrate that in yeast, sterol transport from the plasma membrane to the site of esterification is associated with the physical interaction of the major SOAT, acyl-coenzyme A:cholesterol acyltransferase (ACAT)-related enzyme (Are)2p, with 2 plasma membrane ATP-binding cassette (ABC) transporters: Aus1p and Pdr11p. Are2p, Aus1p, and Pdr11p, unlike the minor acyltransferase, Are1p, colocalize to sterol and sphingolipid-enriched, detergent-resistant microdomains (DRMs). Deletion of either ABC transporter results in Are2p relocalization to detergent-soluble membrane domains and a significant decrease (53-36%) in esterification of exogenous sterol. Similarly, in murine tissues, the SOAT1/Acat1 enzyme and activity localize to DRMs. This subcellular localization is diminished upon deletion of murine ABC transporters, such as Abcg1, which itself is DRM associated. We propose that the close proximity of sterol esterification and transport proteins to each other combined with their residence in lipid-enriched membrane microdomains facilitates rapid, high-capacity sterol transport and esterification, obviating any requirement for soluble intermediary proteins.

  15. Fast and accurate method for total 4-desmethyl sterol(s) content in spreads, fat-blends and raw materials

    NARCIS (Netherlands)

    Duchateau, G.S.M.J.E.; Bauer-Plank, C.G.; Louter, A.J.H.; Ham, M. van der; Boerma, J.A.; Rooijen, J.J.M. van; Zandbelt, P.A.

    2002-01-01

    Plant sterols are added as their FA esters to vegetable oil table spreads at levels of approximately 8% as a means to reduce blood cholesterol levels. A new chromatographic method was designed to quantify quickly the level of plant sterol FA esters in incoming (raw) materials and to monitor their

  16. Comparison of Enzymatic Hydrolysis and Acid Hydrolysis of Sterol Glycosides from Foods Rich in Δ(7)-Sterols.

    Science.gov (United States)

    Münger, Linda H; Jutzi, Sabrina; Lampi, Anna-Maija; Nyström, Laura

    2015-08-01

    In this study, we present the difference in sterol composition of extracted steryl glycosides (SG) hydrolyzed by either enzymatic or acid hydrolysis. SG were analyzed from foods belonging to the plant families Cucurbitaceae (melon and pumpkin seeds) and Amaranthaceae (amaranth and beetroot), both of which are dominated by Δ(7)-sterols. Released sterols were quantified by gas chromatography with a flame ionization detector (GC-FID) and identified using gas chromatography/mass spectrometry (GC-MS). All Δ(7)-sterols identified (Δ(7)-stigmastenyl, spinasteryl, Δ(7)-campesteryl, Δ(7)-avenasteryl, poriferasta-7,25-dienyl and poriferasta-7,22,25-trienyl glucoside) underwent isomerization under acidic conditions and high temperature. Sterols with an ethylidene or methylidene side chain were found to form multiple artifacts. The artifact sterols coeluted with residues of incompletely isomerized Δ(7)-sterols, or Δ(5)-sterols if present, and could be identified as Δ(8(14))-sterols on the basis of relative retention time, and their MS spectra as trimethylsilyl (TMS) and acetate derivatives. For instance, SG from melon were composed of 66% Δ(7)-stigmastenol when enzymatic hydrolysis was performed, whereas with acid hydrolysis only 8% of Δ(7)-stigmastenol was determined. The artifact of Δ(7)-stigmastenol coeluted with residual non-isomerized spinasterol, demonstrating the high risk of misinterpretation of compositional data obtained after acid hydrolysis. Therefore, the accurate composition of SG from foods containing sterols with a double bond at C-7 can only be obtained by enzymatic hydrolysis or by direct analysis of the intact SG.

  17. Sterols of Saccharomyces cerevisiae erg6 Knockout Mutant Expressing the Pneumocystis carinii S-Adenosylmethionine:Sterol C-24 Methyltransferase.

    Science.gov (United States)

    Kaneshiro, Edna S; Johnston, Laura Q; Nkinin, Stephenson W; Romero, Becky I; Giner, José-Luis

    2015-01-01

    The AIDS-associated lung pathogen Pneumocystis is classified as a fungus although Pneumocystis has several distinct features such as the absence of ergosterol, the major sterol of most fungi. The Pneumocystis carinii S-adenosylmethionine:sterol C24-methyltransferase (SAM:SMT) enzyme, coded by the erg6 gene, transfers either one or two methyl groups to the C-24 position of the sterol side chain producing both C28 and C29 24-alkylsterols in approximately the same proportions, whereas most fungal SAM:SMT transfer only one methyl group to the side chain. The sterol compositions of wild-type Sacchromyces cerevisiae, the erg6 knockout mutant (Δerg6), and Δerg6 expressing the P. carinii or the S. cerevisiae erg6 gene were analyzed by a variety of chromatographic and spectroscopic procedures to examine functional complementation in the yeast expression system. Detailed sterol analyses were obtained using high performance liquid chromatography and proton nuclear magnetic resonance spectroscopy ((1)H-NMR). The P. carinii SAM:SMT in the Δerg6 restored its ability to produce the C28 sterol ergosterol as the major sterol, and also resulted in low levels of C29 sterols. This indicates that while the P. carinii SAM:SMT in the yeast Δerg6 cells was able to transfer a second methyl group to the side chain, the action of Δ(24(28)) -sterol reductase (coded by the erg4 gene) in the yeast cells prevented the formation and accumulation of as many C29 sterols as that found in P. carinii.

  18. Sterol Composition in Infant Formulas and Estimated Intake.

    Science.gov (United States)

    Claumarchirant, Lorena; Matencio, Esther; Sanchez-Siles, Luis Manuel; Alegría, Amparo; Lagarda, María Jesús

    2015-08-19

    Sterol contents in infant formulas (IFs) from the European market were determined, and their intakes by infants between 0 and 6 months were evaluated. Total animal sterols (mg/100 mL) ranged from 1.71 to 5.46, cholesterol being the main animal sterol (1.46-5.1). In general, cholesterol and desmosterol were lower than the human milk (HM) values indicated by other authors. Total plant sterol (mg/100 mL) ranged from 3.1 to 5.0. β-Sitosterol, the most abundant phytosterol, ranged from 1.82 to 3.01, followed by campesterol (0.72-1.15), stigmasterol (0.27-0.53), and brassicasterol (0.14-0.28). Cholesterol intake (mg/day) ranged from 9 to 51 and plant sterol intake (mg/day) from 19 to 50. The sterol profile of IFs is highly dependent on the type and quantity of fats used in their formula. The use of bovine milk fat and milk fat globule membrane in the IFs can approximate the profile of animal sterols to those found in HM, though cholesterol intakes in breastfed infants are still higher than in formula-fed infants.

  19. Sterols of a contemporary lacustrine sediment. [in English postglacial lake

    Science.gov (United States)

    Gaskell, S. J.; Eglinton, G.

    1976-01-01

    Results are reported for detailed sterol analyses of several depths (corresponding to between zero and about 150 yr in age) in a contemporary lacustrine sediment from a freshwater lake of postglacial origin in England. Delta 5-, delta 22-, and delta 5,22-sterols are identified along with 5 alpha- and 5 beta-stanols as well as a C26 stanol with a C7 side chain. Solvent extraction yields carbon number distributions for the 5 alpha- and 5 beta-stanol sediment constituents that parallel the corresponding delta 5-sterol distributions. The amounts of 5 alpha-stanols are found to exceed those of 5 beta-stanols in the sediment, and variations in the ratio of 5 alpha- to 5 beta-stanol between sediment samples from similar depths are shown to suggest an inhomogeneity of the sediment. It is found that the sterol composition of sediment cores varies markedly with depth, reflecting both the effects of a sterol hydrogenation process and a changing input to the sediment. It is concluded that C29 sterols, of probable higher-plant origin, predominate at lower sediment depths while C27 sterols, possibly derived from autochthonous sources, are more abundant in the surface sediment.

  20. Sterols of a contemporary lacustrine sediment. [in English postglacial lake

    Science.gov (United States)

    Gaskell, S. J.; Eglinton, G.

    1976-01-01

    Results are reported for detailed sterol analyses of several depths (corresponding to between zero and about 150 yr in age) in a contemporary lacustrine sediment from a freshwater lake of postglacial origin in England. Delta 5-, delta 22-, and delta 5,22-sterols are identified along with 5 alpha- and 5 beta-stanols as well as a C26 stanol with a C7 side chain. Solvent extraction yields carbon number distributions for the 5 alpha- and 5 beta-stanol sediment constituents that parallel the corresponding delta 5-sterol distributions. The amounts of 5 alpha-stanols are found to exceed those of 5 beta-stanols in the sediment, and variations in the ratio of 5 alpha- to 5 beta-stanol between sediment samples from similar depths are shown to suggest an inhomogeneity of the sediment. It is found that the sterol composition of sediment cores varies markedly with depth, reflecting both the effects of a sterol hydrogenation process and a changing input to the sediment. It is concluded that C29 sterols, of probable higher-plant origin, predominate at lower sediment depths while C27 sterols, possibly derived from autochthonous sources, are more abundant in the surface sediment.

  1. Sterol composition from inflorescences of Hieracium pilosella L.

    Directory of Open Access Journals (Sweden)

    Tadeusz Krzaczek

    2011-01-01

    Full Text Available The fraction of sterol acetates from the inflorescences of Hieracium pilosella has been isolated in the typical way from petroleum ether extract. By means of the weight method the total amount of sterols was determined (0.2659%. The mixtures of sterol acetates and free sterols were investigated using GC-MS techniques. The occurrence of about 18 sterols has been observed. Cholesterol, cholest-8(14-en-3b-ol, cholesta-5.7-dien-3b-ol, cholest-7-en-3b-ol, ergosta-5.24-dien-3b-ol, campesterol, stigmasterol, b-sitosterol, fucosterol, 5a-stigmast-7-en-3a-ol were identified. The probable structures of lophenol, isofucosterol, 5a-stigmasta-7.24-dien-3b-ol, lanosta-9(11.24-dien-3b-ol and 24-ethylidene lophenol were stated on the basis of literature data. The last 4 sterols occur in a vestigial quantity, which made its identification impossible. Sitos erol and cholesterol are remarkably dominating sterols in the fraction.

  2. Quantification of sterol lipids in plants by quadrupole time-of-flight mass spectrometry

    Science.gov (United States)

    Wewer, Vera; Dombrink, Isabel; vom Dorp, Katharina; Dörmann, Peter

    2011-01-01

    Glycerolipids, sphingolipids, and sterol lipids constitute the major lipid classes in plants. Sterol lipids are composed of free and conjugated sterols, i.e., sterol esters, sterol glycosides, and acylated sterol glycosides. Sterol lipids play crucial roles during adaption to abiotic stresses and plant-pathogen interactions. Presently, no comprehensive method for sterol lipid quantification in plants is available. We used nanospray ionization quadrupole-time-of-flight mass spectrometry (Q-TOF MS) to resolve and identify the molecular species of all four sterol lipid classes from Arabidopsis thaliana. Free sterols were derivatized with chlorobetainyl chloride. Sterol esters, sterol glycosides, and acylated sterol glycosides were ionized as ammonium adducts. Quantification of molecular species was achieved in the positive mode after fragmentation in the presence of internal standards. The amounts of sterol lipids quantified by Q-TOF MS/MS were validated by comparison with results obtained with TLC/GC. Quantification of sterol lipids from leaves and roots of phosphate-deprived A. thaliana plants revealed changes in the amounts and molecular species composition. The Q-TOF method is far more sensitive than GC or HPLC. Therefore, Q-TOF MS/MS provides a comprehensive strategy for sterol lipid quantification that can be adapted to other tandem mass spectrometers. PMID:21382968

  3. Neutral Sterols of Cephalic Glands of Stingless Bees and Their Correlation with Sterols from Pollen

    Directory of Open Access Journals (Sweden)

    Maria Juliana Ferreira-Caliman

    2012-01-01

    de novo and, thus, all phytophagous insects depend on an exogenous source of sterols for growth, development, and reproduction. The sterol requirements of social bees are not fully known due to the fact that there is no well-defined diet available throughout the year with regard to floral resources. Our study aimed to characterize the sterols present in pollen stored in Melipona marginata and Melipona scutellaris colonies, as well as evaluating their presence in the mandibular, hypopharyngeal, and cephalic salivary gland secretions. We analyzed the chemical composition of pollen stored in the colonies and the composition of the cephalic glands of workers in three adult functional phases (newly emerged, nurses, and foragers by gas chromatography and mass spectrometry. The results showed that the pollen analyzed contained campesterol, stigmasterol, sitosterol, isofucosterol, lanosterol, and small amounts of cholesterol. The glands showed the same compounds found in the pollen analyzed, except lanosterol that was not found in M. scutellaris glands. Surprisingly, cholesterol was found in some glands with relative ratios greater than those found in pollen.

  4. Paleoproterozoic sterol biosynthesis and the rise of oxygen

    Science.gov (United States)

    Gold, David A.; Caron, Abigail; Fournier, Gregory P.; Summons, Roger E.

    2017-03-01

    Natural products preserved in the geological record can function as ‘molecular fossils’, providing insight into organisms and physiologies that existed in the deep past. One important group of molecular fossils is the steroidal hydrocarbons (steranes), which are the diagenetic remains of sterol lipids. Complex sterols with modified side chains are unique to eukaryotes, although simpler sterols can also be synthesized by a few bacteria. Sterol biosynthesis is an oxygen-intensive process; thus, the presence of complex steranes in ancient rocks not only signals the presence of eukaryotes, but also aerobic metabolic processes. In 1999, steranes were reported in 2.7 billion year (Gyr)-old rocks from the Pilbara Craton in Australia, suggesting a long delay between photosynthetic oxygen production and its accumulation in the atmosphere (also known as the Great Oxidation Event) 2.45-2.32 Gyr ago. However, the recent reappraisal and rejection of these steranes as contaminants pushes the oldest reported steranes forward to around 1.64 Gyr ago (ref. 6). Here we use a molecular clock approach to improve constraints on the evolution of sterol biosynthesis. We infer that stem eukaryotes shared functionally modern sterol biosynthesis genes with bacteria via horizontal gene transfer. Comparing multiple molecular clock analyses, we find that the maximum marginal probability for the divergence time of bacterial and eukaryal sterol biosynthesis genes is around 2.31 Gyr ago, concurrent with the most recent geochemical evidence for the Great Oxidation Event. Our results therefore indicate that simple sterol biosynthesis existed well before the diversification of living eukaryotes, substantially predating the oldest detected sterane biomarkers (approximately 1.64 Gyr ago), and furthermore, that the evolutionary history of sterol biosynthesis is tied to the first widespread availability of molecular oxygen in the ocean-atmosphere system.

  5. Paleoproterozoic sterol biosynthesis and the rise of oxygen.

    Science.gov (United States)

    Gold, David A; Caron, Abigail; Fournier, Gregory P; Summons, Roger E

    2017-03-16

    Natural products preserved in the geological record can function as 'molecular fossils', providing insight into organisms and physiologies that existed in the deep past. One important group of molecular fossils is the steroidal hydrocarbons (steranes), which are the diagenetic remains of sterol lipids. Complex sterols with modified side chains are unique to eukaryotes, although simpler sterols can also be synthesized by a few bacteria. Sterol biosynthesis is an oxygen-intensive process; thus, the presence of complex steranes in ancient rocks not only signals the presence of eukaryotes, but also aerobic metabolic processes. In 1999, steranes were reported in 2.7 billion year (Gyr)-old rocks from the Pilbara Craton in Australia, suggesting a long delay between photosynthetic oxygen production and its accumulation in the atmosphere (also known as the Great Oxidation Event) 2.45-2.32 Gyr ago. However, the recent reappraisal and rejection of these steranes as contaminants pushes the oldest reported steranes forward to around 1.64 Gyr ago (ref. 6). Here we use a molecular clock approach to improve constraints on the evolution of sterol biosynthesis. We infer that stem eukaryotes shared functionally modern sterol biosynthesis genes with bacteria via horizontal gene transfer. Comparing multiple molecular clock analyses, we find that the maximum marginal probability for the divergence time of bacterial and eukaryal sterol biosynthesis genes is around 2.31 Gyr ago, concurrent with the most recent geochemical evidence for the Great Oxidation Event. Our results therefore indicate that simple sterol biosynthesis existed well before the diversification of living eukaryotes, substantially predating the oldest detected sterane biomarkers (approximately 1.64 Gyr ago), and furthermore, that the evolutionary history of sterol biosynthesis is tied to the first widespread availability of molecular oxygen in the ocean-atmosphere system.

  6. Sterol composition of the Adriatic Sea algae Ulva lactuca, Codium dichotomum, Cystoseira adriatica and Fucus virsoides

    Directory of Open Access Journals (Sweden)

    RADOMIR KAPETANOVIC

    2005-12-01

    Full Text Available The sterol composition of two green algae and two brown algae from the South Adriatic was determined. In the green alga Ulva lactuca, the principal sterols were cholesterol and isofucosterol. In the brown alga Cystoseira adriatica, the main sterols were cholesterol and stigmast-5-en-3ß-ol, while the characteristic sterol of the brown algae, fucosterol, was found only in low concentration. The sterol fractions of the green alga Codium dichotomum and the brown alga Fucus virsoides contained practically only one sterol each, comprising more than 90 % of the total sterols (clerosterol in the former and fucosterol in the latter.

  7. Two New C29 Sterols from Clerodendrum colebrookianum

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    From the aerial parts of Clerodendrum colebrookianum Walp., two new C29 sterols, colebrin A and colebrin B, were isolated, along with a known compound, clerosterol .The structures of the new compounds were elucidated on the basis of spectral evidence.

  8. New cytotoxic oxygenated sterols from the marine bryozoan Cryptosula pallasiana.

    Science.gov (United States)

    Tian, Xiang-Rong; Tang, Hai-Feng; Li, Yu-Shan; Lin, Hou-Wen; Chen, Xiao-Li; Ma, Ning; Yao, Min-Na; Zhang, Ping-Hu

    2011-01-28

    Six new sterols (1-6), together with seven known sterols (7-13), were isolated from the CCl(4) extract of the marine bryozoan Cryptosula pallasiana, four (3-6) of which have already been reported as synthetic sterols. This is the first time that these compounds (3-6) are reported as natural sterols. The structures of the new compounds were determined on the basis of the extensive spectroscopic analysis, including two-dimensional (2D) NMR and HR-ESI-MS data. Compounds 1-4, 7 and 10-13 were evaluated for their cytotoxicity against HL-60 human myeloid leukemia cell line, and all of the evaluated compounds exhibited moderate cytotoxicity to HL-60 cells with a range of IC(50) values from 14.73 to 22.11 µg/mL except for compounds 12 and 13.

  9. New Cytotoxic Oxygenated Sterols from the Marine Bryozoan Cryptosula pallasiana

    Directory of Open Access Journals (Sweden)

    Ping-Hu Zhang

    2011-01-01

    Full Text Available Six new sterols (1–6, together with seven known sterols (7–13, were isolated from the CCl4 extract of the marine bryozoan Cryptosula pallasiana, four (3–6 of which have already been reported as synthetic sterols. This is the first time that these compounds (3–6 are reported as natural sterols. The structures of the new compounds were determined on the basis of the extensive spectroscopic analysis, including two-dimensional (2D NMR and HR-ESI-MS data. Compounds 1–4, 7 and 10–13 were evaluated for their cytotoxicity against HL-60 human myeloid leukemia cell line, and all of the evaluated compounds exhibited moderate cytotoxicity to HL-60 cells with a range of IC50 values from 14.73 to 22.11 µg/mL except for compounds 12 and 13.

  10. Kinetic imaging of NPC1L1 and sterol trafficking between plasma membrane and recycling endosomes in hepatoma cells

    DEFF Research Database (Denmark)

    Hartwig Petersen, Nicole; Færgeman, Nils J; Yu, Liqing;

    2008-01-01

    Niemann-Pick C1-like 1 (NPC1L1) is a recently identified protein that mediates intestinal cholesterol absorption and regulates biliary cholesterol excretion. The itineraries and kinetics of NPC1L1 trafficking remain uncertain. In this study, we have visualized movement of NPC1L1-enhanced green...... fluorescent protein (NPC1L1-EGFP) and cholesterol analogues in hepatoma cells. At steady state about 42% of NPC1L1 resided in the transferrin (Tf) positive, sterol enriched endocytic recycling compartment (ERC), while time-lapse microscopy demonstrated NPC1L1 traffic between plasma membrane and ERC...... exclusively in the canalicular membrane, where the protein is highly mobile. Our study demonstrates dynamic trafficking of NPC1L1 between cell surface and intracellular compartments and suggests that this transport is involved in NPC1L1 mediated cellular sterol uptake....

  11. Sterols in a unicellular relative of the metazoans

    Science.gov (United States)

    Kodner, Robin B.; Summons, Roger E.; Pearson, Ann; King, Nicole; Knoll, Andrew H.

    2008-01-01

    Molecular clocks suggest that animals originated well before they first appear as macroscopic fossils, but geologic tests of these hypotheses have been elusive. A rare steroid hydrocarbon, 24-isopropylcholestane, has been hypothesized to be a biomarker for sponges or their immediate ancestors because of its relatively high abundance in pre-Ediacaran to Early Cambrian sedimentary rocks and oils. Biolipid precursors of this sterane have been reported to be prominent in several demosponges. Whether 24-isopropylcholestane can be interpreted as a sponge (and, hence, animal) biomarker, and so provide clues about early metazoan history, depends on an understanding of the distribution of sterol biosynthesis among animals and their protistan relatives. Accordingly, we characterized the sterol profile of the choanoflagellate Monosiga brevicollis, a representative of the unicellular sister group of animals. M. brevicollis does not produce a candidate sterol precursor for 24-isopropylcholestane under our experimental growth conditions. It does, however, produce a number of other sterols, and comparative genomics confirms its biosynthetic potential to produce the full suite of compounds recovered. Consistent with the phylogenetic position of choanoflagellates, the sterol profile and biosynthetic pathway of M. brevicollis display characteristics of both fungal and poriferan sterol biosynthesis. This is an example in which genomic and biochemical information have been used together to investigate the taxonomic specificity of a fossil biomarker. PMID:18632573

  12. Fiber, intestinal sterols, and colon cancer.

    Science.gov (United States)

    Huang, C T; Gopalakrishna, G S; Nichols, B L

    1978-03-01

    It has been postulated that dietary fiber's protective effect against the development of colon cancer, diverticular disease, and atherosclerosis may be due to the adsorption and/or dilution of intestinal sterols such as bile acids and neural sterols and their bacterial metabolites by component(s) of fiber. Dietary fiber is made up of four major components-cellulose, hemicellulose, lignin, and pectin. There is evidence that hemicellulose and pectin may induce an increase in fecal bile acid excretion in man which may be accompanied by a decrease in serum cholesterol. Natural fibers, such as rolled oats, alfalfa, guar gum, and Bengal gram have been shown to have hypocholesterolemic properties of alfalfa, wheat straw, and some other fibers found considerable amounts of bile acids in vitro. On the other hand, wheat bran, oat hulls, and all the synthetic fibers tested bound only negligible amounts of bile acids under the same conditions. Vegetarians in the United States have lower plasma lipids and different plasma lipoprotein patterns than those of comparable control populations on regular mixed diet. They also have smaller daily fractional turnover rates of cholic acid and deoxycholic acid pool size. In addition, populations on a mixed Western diet, where the rate of large bowel cancer is high (North American, English, Scottish, etc.) degraded and excreted cholesterol and bile acid metabolites to a greater degree than populations where the rate of colon cancer is comparatively low (Ugandan, Japanese, etc). It cannot be denied that the fiber theory linking fiber deficiency with the development of colon cancer and other diseases, is simple, attractive and appears to be firmly based in common sense. When subjected to research studies, however, the situation appears much more complex than expected. Although some progress is being made, the data are often contradictory and confusing, probably due to lack of adequate documentation of fiber intake (e.g., use of dietary fiber

  13. SURVEY OF THE STEROL COMPOSITION OF THE MARINE DINOFLAGELLATES KARENIA BREVIS, KARENIA MIKIMOTOI, AND KARLODINIUM MICRUM: DISTRIBUTION OF STEROLS WITHIN OTHER MEMBERS OF THE CLASS DINOPHYCEAE

    Science.gov (United States)

    The sterol composition of different marine microalgae was examined to determine the utility of sterols as biomarkers to distinguish members of various algal classes. For example, members of the class Dinophyceae possess certain 4-methyl sterols, such as dinosterol, which are rare...

  14. Activation of Sterol Regulatory Element Binding Factors by Fenofibrate and Gemfibrozil Stimulate Myelination in Zebrafish

    Directory of Open Access Journals (Sweden)

    Yuhei Nishimura

    2016-07-01

    Full Text Available Oligodendrocytes are major myelin-producing cells and play essential roles in the function of a healthy nervous system. However, they are also one of the most vulnerable neural cell types in the central nervous system (CNS, and myelin abnormalities in the CNS are found in a wide variety of neurological disorders, including multiple sclerosis, adrenoleukodystrophy, and schizophrenia. There is an urgent need to identify small molecular weight compounds that can stimulate myelination. In this study, we performed comparative transcriptome analysis to identify pharmacodynamic effects common to miconazole and clobetasol, which have been shown to stimulate myelination by mouse oligodendrocyte progenitor cells (OPCs. Of the genes differentially expressed in both miconazole- and clobetasol-treated mouse OPCs compared with untreated cells, we identified differentially expressed genes (DEGs common to both drug treatments. Gene ontology analysis revealed that these DEGs are significantly associated with the sterol biosynthetic pathway, and further bioinformatics analysis suggested that sterol regulatory element binding factors (SREBFs might be key upstream regulators of the DEGs. In silico screening of a public database for chemicals associated with SREBF activation identified fenofibrate, a peroxisome proliferator-activated receptor α (PPARα agonist, as a drug that increases the expression of known SREBF targets, raising the possibility that fenofibrate may also stimulate myelination. To test this, we performed in vivo imaging of zebrafish expressing a fluorescent reporter protein under the control of the myelin basic protein (mbp promoter. Treatment of zebrafish with fenofibrate significantly increased expression of the fluorescent reporter compared with untreated zebrafish. This increase was attenuated by co-treatment with fatostatin, a specific inhibitor of SREBFs, confirming that the fenofibrate effect was mediated via SREBFs. Furthermore, incubation

  15. Identifying avian sources of faecal contamination using sterol analysis.

    Science.gov (United States)

    Devane, Megan L; Wood, David; Chappell, Andrew; Robson, Beth; Webster-Brown, Jenny; Gilpin, Brent J

    2015-10-01

    Discrimination of the source of faecal pollution in water bodies is an important step in the assessment and mitigation of public health risk. One tool for faecal source tracking is the analysis of faecal sterols which are present in faeces of animals in a range of distinctive ratios. Published ratios are able to discriminate between human and herbivore mammal faecal inputs but are of less value for identifying pollution from wildfowl, which can be a common cause of elevated bacterial indicators in rivers and streams. In this study, the sterol profiles of 50 avian-derived faecal specimens (seagulls, ducks and chickens) were examined alongside those of 57 ruminant faeces and previously published sterol profiles of human wastewater, chicken effluent and animal meatwork effluent. Two novel sterol ratios were identified as specific to avian faecal scats, which, when incorporated into a decision tree with human and herbivore mammal indicative ratios, were able to identify sterols from avian-polluted waterways. For samples where the sterol profile was not consistent with herbivore mammal or human pollution, avian pollution is indicated when the ratio of 24-ethylcholestanol/(24-ethylcholestanol + 24-ethylcoprostanol + 24-ethylepicoprostanol) is ≥0.4 (avian ratio 1) and the ratio of cholestanol/(cholestanol + coprostanol + epicoprostanol) is ≥0.5 (avian ratio 2). When avian pollution is indicated, further confirmation by targeted PCR specific markers can be employed if greater confidence in the pollution source is required. A 66% concordance between sterol ratios and current avian PCR markers was achieved when 56 water samples from polluted waterways were analysed.

  16. Sterols of Pneumocystis carinii hominis Organisms Isolated from Human Lungs

    Science.gov (United States)

    Kaneshiro, Edna S.; Amit, Zunika; Chandra, Jyotsna; Baughman, Robert P.; Contini, Carlo; Lundgren, Bettina

    1999-01-01

    The opportunistic pathogen Pneumocystis carinii causes pneumonia (P. carinii pneumonia, or PCP) in immunocompromised individuals such as AIDS patients. Rat-derived P. carinii carinii organisms have distinct sterols which are not synthesized by mammals and not found in other microbes infecting mammalian lungs. The dominant sterol present in the organism is cholesterol (which is believed to be scavenged from the host), but other sterols in P. carinii carinii have an alkyl group at C-24 of the sterol side chain (C28 and C29 24-alkylsterols) and a double bond at C-7 of the nucleus. Recently, pneumocysterol (C32), which is essentially lanosterol with a C-24 ethylidene group, was detected in lipids extracted from a formalin-fixed human P. carinii-infected lung, and its structures were elucidated by gas-liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectrometry in conjunction with analyses of chemically synthesized authentic standards. The sterol composition of isolated P. carinii hominis organisms has yet to be reported. If P. carinii from animal models is to be used for identifying potential drug targets and for developing chemotherapeutic approaches to clear human infections, it is important to determine whether the 24-alkylsterols of organisms found in rats are also present in organisms in humans. In the present study, sterol analyses of P. carinii hominis organisms isolated from cryopreserved human P. carinii-infected lungs and from bronchoalveolar lavage fluid were performed. Several of the same distinct sterols (e.g., fungisterol and methylcholest-7-ene-3β-ol) previously identified in P. carinii carinii were also present in organisms isolated from human specimens. Pneumocysterol was detected in only some of the samples. PMID:10548595

  17. Free and Esterified Sterol Distribution in Four Romanian Vegetable Oil

    Directory of Open Access Journals (Sweden)

    Francisc Vasile DULF

    2010-09-01

    Full Text Available The unsaponifiable lipid fraction of plant-based foods is a potential source of bioactive components such as phytosterols, triterpenoids, carotenoids, tocopherols and various hydrocarbons. The free and esterified sterol concentrations in four Romanian edible oils (corn germ, wheat germ, sweet almond and grape seed oil were determined, including individual values for β-sitosterol, campesterol, stigmasterol, Δ5-avenasterol, sitostanol, campestanol, and cholesterol. Free and esterified sterols were separated by solid-phase extraction (SPE, saponified, and analyzed as trimethylsilyl ether derivatives using gas-chromatography (GC with flame ionization detector (FID. Differences in total sterol content and the proportion of esterified (ES and free sterols (FS were evident for studied oil samples. In general, β-sitosterol was the most prevalent phytosterol, ranging in concentration from 158.3 mg/100 g in grape seed oil to 478.5 mg/100 g in corn germ oil. Only in these two vegetable oil, we identified trace amount of cholesterol (<3 mg/100g. The total sterol concentrations ranged from 199.9 mg/100g (sweet almond oil to 745.2 mg/100 g (corn germ oil. In corn germ and wheat germ oil, the dominant form of sterols was the esterified one (60.7% ES and 55.6% ES, respectively, of total sterols. This study consolidates the view that vegetable oils are good natural sources of phytosterols. The analyses of these components provide rich information about the identity and quality of vegetable oils. The corn germ and wheat germ oils proved to be the richest sources in phytosterols, being recommended as functional oils.

  18. Detection of non-sterol isoprenoids by HPLC-MS/MS

    Science.gov (United States)

    Henneman, Linda; van Cruchten, Arno G.; Denis, Simone W.; Amolins, Michael W.; Placzek, Andrew T.; Gibbs, Richard A.; Kulik, Willem; Waterham, Hans R.

    2012-01-01

    Isoprenoids constitute an important class of biomolecules that participate in many different cellular processes. Most available detection methods only allow the identification of one or two specific non-sterol isoprenoid intermediates following radioactive or fluorescent labeling. We here report a rapid, non-radioactive and sensitive procedure for the simultaneous detection and quantification of the 8 main non-sterol intermediates of the isoprenoid biosynthesis pathway by means of tandem mass spectrometry. Intermediates were analyzed by HPLC-MS/MS in the multiple reaction monitoring mode using a silica-based C18 HPLC column. For quantification, their stable-isotope-labeled analogues were used as internal standards. HepG2 cells were used to validate the method. Mevalonate, phosphomevalonate and the 6 subsequent isoprenoid-pyrophosphates were readily determined with detection limits ranging from 0.03 to 1.0 μmol/L. The intra- and interassay variations for HepG2 cell homogenates supplemented with isoprenoid intermediates were 3.6–10.9% and 4.4–11.9%, respectively. Under normal culturing conditions, isoprenoid intermediates in HepG2 cells were below detection limits. However, incubation of the cells with pamidronate, an inhibitor of farnesyl pyrophosphate synthase, resulted in increased levels of MVA, IPP/DMAPP and GPP. This method will be suitable to measure profiles of isoprenoid intermediates in cells with compromised isoprenoid biosynthesis, and to determine the specificity of potential inhibitors of the pathway. PMID:18782552

  19. Sterols indicate water quality and wastewater treatment efficiency.

    Science.gov (United States)

    Reichwaldt, Elke S; Ho, Wei Y; Zhou, Wenxu; Ghadouani, Anas

    2017-01-01

    As the world's population continues to grow, water pollution is presenting one of the biggest challenges worldwide. More wastewater is being generated and the demand for clean water is increasing. To ensure the safety and health of humans and the environment, highly efficient wastewater treatment systems, and a reliable assessment of water quality and pollutants are required. The advance of holistic approaches to water quality management and the increasing use of ecological water treatment technologies, such as constructed wetlands and waste stabilisation ponds (WSPs), challenge the appropriateness of commonly used water quality indicators. Instead, additional indicators, which are direct measures of the processes involved in the stabilisation of human waste, have to be established to provide an in-depth understanding of system performance. In this study we identified the sterol composition of wastewater treated in WSPs and assessed the suitability of human sterol levels as a bioindicator of treatment efficiency of wastewater in WSPs. As treatment progressed in WSPs, the relative abundance of human faecal sterols, such as coprostanol, epicoprostanol, 24-ethylcoprostanol, and sitostanol decreased significantly and the sterol composition in wastewater changed significantly. Furthermore, sterol levels were found to be correlated with commonly used wastewater quality indicators, such as BOD, TSS and E. coli. Three of the seven sterol ratios that have previously been used to track sewage pollution in the environment, detected a faecal signal in the effluent of WSPs, however, the others were influenced by high prevalence of sterols originating from algal and fungal activities. This finding poses a concern for environmental assessment studies, because environmental pollution from waste stabilisation ponds can go unnoticed. In conclusion, faecal sterols and their ratios can be used as reliable indicators of treatment efficiency and water quality during wastewater

  20. Plant phloem sterol content: forms, putative functions, and implications for phloem-feeding insects

    Directory of Open Access Journals (Sweden)

    Spencer eBehmer

    2013-09-01

    Full Text Available All eukaryotes contain sterols, which serve as structural components in cell membranes, and as precursors for important hormones. Plant vegetative tissues are known to contain mixtures of sterols, but very little is known about the sterol composition of phloem. Plants are food for many animals, but plant-feeding arthropods (including phloem-feeding insets are unique among animals in that they have lost the ability to synthesize sterols, and must therefore acquire these essential nutrients from their food, or via endosymbionts. Our paper starts by providing a very brief overview of variation in plant sterol content, and how different sterols can affect insect herbivores, including those specializing on phloem. We then describe an experiment, where we bulk collected phloem sap exudate from bean and tobacco, and analyzed its sterol content. This approach revealed two significant observations concerning phloem sterols. First, the phloem exudate from each plant was found to contain sterols in three different fractions – free sterols, sterols conjugated to lipids (acylated, and sterols conjugated to carbohydrates (glycosylated. Second, for both plants, cholesterol was identified as the dominant sterol in each phloem exudate fraction; the remaining sterol in the fraction was a mixture of common phytosterols. We discuss our phloem exudate sterol profiles in a plant physiology/biochemistry context, and how it relates to the nutritional physiology/ecology of phloem-feeding insects. We close by proposing important next steps that will advance our knowledge concerning plant phloem sterol biology, and how phloem-sterol content might affect phloem-feeding insects.

  1. Sterols as biomarkers in the surface microlayer of the estuarine areas.

    Science.gov (United States)

    Alsalahi, Murad Ali; Latif, Mohd Talib; Ali, Masni Mohd; Dominick, Doreena; Khan, Md Firoz; Mustaffa, Nur Ili Hamizah; Nadzir, Mohd Shahrul Mohd; Nasher, Essam; Zakaria, Mohamad Pauzi

    2015-04-15

    This study aims to determine the concentration of sterols used as biomarkers in the surface microlayer (SML) in estuarine areas of the Selangor River, Malaysia. Samples were collected during different seasons through the use of a rotation drum. The analysis of sterols was performed using gas chromatography equipped with a flame ionisation detector (GC-FID). The results showed that the concentrations of total sterols in the SML ranged from 107.06 to 505.55 ng L(-1). The total sterol concentration was found to be higher in the wet season. Cholesterol was found to be the most abundant sterols component in the SML. The diagnostic ratios of sterols show the influence of natural sources and waste on the contribution of sterols in the SML. Further analysis, using principal component analysis (PCA), showed distinct inputs of sterols derived from human activity (40.58%), terrigenous and plant inputs (22.59%) as well as phytoplankton and marine inputs (17.35%).

  2. Comparative seasonal sterol profiles in edible parts of Mediterranean fish and shellfish species.

    Science.gov (United States)

    Ozyurt, Gülsün; Kuley, Esmeray; Etyemez, Miray; Ozoğul, Fatih

    2013-06-01

    The effect of different seasons on sterol content of seafoods was investigated. There were four sterols (cholesterol, sitosterol, desmosterol and stigmasterol) identified, with cholesterol being the predominant sterol. Stigmasterol was a minor component in fish muscle, whilst sitosterol was one of the main phytosterols found in fish muscle. Cholesterol content of fish consisted of 38-100% of total sterols in fish and 54-80% of total sterols in shellfish. The highest cholesterol content of fish muscle was found in summer and the lowest in autumn, whereas season did not have any effect on cholesterol level of green tiger prawn and speckled shrimp. Total sterol content of fish muscle ranged from 49 to 110 mg/100 g, although the range of total sterols in shrimp muscle was between 62 and 91 mg/100 g. The result of the study showed that total sterols in fish were generally found at lower levels in winter compared with other seasons.

  3. A data mining approach to dinoflagellate clustering according to sterol composition: Correlations with evolutionary history.

    Science.gov (United States)

    This study examined the sterol compositions of 102 dinoflagellates (including several previously unexamined species) using clustering techniques as a means of determining the relatedness of the organisms. In addition, dinoflagellate sterol-based relationships were compared statistically to dinoflag...

  4. Sterols and sphingolipids: Dynamic duo or partners in crime?

    Science.gov (United States)

    Gulati, Sonia; Liu, Ying; Munkacsi, Andrew B.; Wilcox, Lisa; Sturley, Stephen L.

    2010-01-01

    One manner in which eukaryotic cells respond to their environments is by optimizing the composition and proportions of sterols and sphingolipids in membranes. The physical association of the planar ring of sterols with the acyl chains of phospholipids, particularly sphingolipids, produces membrane micro-heterogeneity that is exploited to coordinate several crucial pathways. We hypothesize that these lipid molecules play an integrated role in human disease; when one of the partners is mis-regulated, pathology frequently ensues. Sterols and sphingolipid levels are not coordinated by the action of a single master regulator, however the cross talk between their metabolic pathways is considerable. We describe our perspectives on the key components of synthesis, catabolism and transport of these lipid partners with an emphasis on evolutionarily conserved reactions that produce disease states when defective. PMID:20362613

  5. New Marine Sterols from a Gorgonian Pinnigorgia sp.

    Science.gov (United States)

    Chang, Yu-Chia; Hwang, Tsong-Long; Chao, Chih-Hua; Sung, Ping-Jyun

    2017-03-03

    Continuous chemical investigation of the gorgonian coral Pinnigorgia sp. resulted in the isolation of two new sterols, 5α,6α-epoxy-(22E,24R)-3β,11-dihydroxy-9,11-secoergosta-7-en-9-one (1) and (22R)-acetoxy-(24ξ)-ergosta-5-en-3β,25-diol (2). The structures of sterols 1 and 2 were elucidated using spectroscopic methods. Sterol 1 displayed inhibitory effects on the generation of superoxide anions and the release of elastase by human neutrophils with IC50 values of 8.65 and 5.86 μM, respectively. The structure of a known metabolite, pubinernoid A (3), is revised as (+)-loliolide (4).

  6. Sterol and genomic analyses validate the sponge biomarker hypothesis.

    Science.gov (United States)

    Gold, David A; Grabenstatter, Jonathan; de Mendoza, Alex; Riesgo, Ana; Ruiz-Trillo, Iñaki; Summons, Roger E

    2016-03-01

    Molecular fossils (or biomarkers) are key to unraveling the deep history of eukaryotes, especially in the absence of traditional fossils. In this regard, the sterane 24-isopropylcholestane has been proposed as a molecular fossil for sponges, and could represent the oldest evidence for animal life. The sterane is found in rocks ∼650-540 million y old, and its sterol precursor (24-isopropylcholesterol, or 24-ipc) is synthesized today by certain sea sponges. However, 24-ipc is also produced in trace amounts by distantly related pelagophyte algae, whereas only a few close relatives of sponges have been assayed for sterols. In this study, we analyzed the sterol and gene repertoires of four taxa (Salpingoeca rosetta, Capsaspora owczarzaki, Sphaeroforma arctica, and Creolimax fragrantissima), which collectively represent the major living animal outgroups. We discovered that all four taxa lack C30 sterols, including 24-ipc. By building phylogenetic trees for key enzymes in 24-ipc biosynthesis, we identified a candidate gene (carbon-24/28 sterol methyltransferase, or SMT) responsible for 24-ipc production. Our results suggest that pelagophytes and sponges independently evolved C30 sterol biosynthesis through clade-specific SMT duplications. Using a molecular clock approach, we demonstrate that the relevant sponge SMT duplication event overlapped with the appearance of 24-isopropylcholestanes in the Neoproterozoic, but that the algal SMT duplication event occurred later in the Phanerozoic. Subsequently, pelagophyte algae and their relatives are an unlikely alternative to sponges as a source of Neoproterozoic 24-isopropylcholestanes, consistent with growing evidence that sponges evolved long before the Cambrian explosion ∼542 million y ago.

  7. Simultaneous Effects of Light Intensity and Phosphorus Supply on the Sterol Content of Phytoplankton

    OpenAIRE

    Maike Piepho; Dominik Martin-Creuzburg; Alexander Wacker

    2010-01-01

    Sterol profiles of microalgae and their change with environmental conditions are of great interest in ecological food web research and taxonomic studies alike. Here, we investigated effects of light intensity and phosphorus supply on the sterol content of phytoplankton and assessed potential interactive effects of these important environmental factors on the sterol composition of algae. We identified sterol contents of four common phytoplankton genera, Scenedesmus, Chlamydomonas, Cryptomonas ...

  8. Study on sterols from brown algae (Sargassum muticum)

    Institute of Scientific and Technical Information of China (English)

    WANG Peirong; XU Guanjun; BIAN Lizeng; ZHANG Shuichang; SONG Fuqing

    2006-01-01

    Various △5-3β-sterenols, whose carbon numbers range from C19-C23 to C26-C30and some compounds have many stereomers maximal up to six,have been detected out from the extract of brown algae (Sargassum muticum), which means that steranes with lower carbon numbers are likely different in the origin, and some corresponding sterol stereoisomers may have already existed in their precursor organisms. This provides some experimental evidence for supplementing and amending the traditional interpretation of the sterol stereoisomer transformation during the deposition and diagenesis of organic matter.

  9. Sterol Biosynthesis Pathway as Target for Anti-trypanosomatid Drugs

    Directory of Open Access Journals (Sweden)

    Wanderley de Souza

    2009-01-01

    Full Text Available Sterols are constituents of the cellular membranes that are essential for their normal structure and function. In mammalian cells, cholesterol is the main sterol found in the various membranes. However, other sterols predominate in eukaryotic microorganisms such as fungi and protozoa. It is now well established that an important metabolic pathway in fungi and in members of the Trypanosomatidae family is one that produces a special class of sterols, including ergosterol, and other 24-methyl sterols, which are required for parasitic growth and viability, but are absent from mammalian host cells. Currently, there are several drugs that interfere with sterol biosynthesis (SB that are in use to treat diseases such as high cholesterol in humans and fungal infections. In this review, we analyze the effects of drugs such as (a statins, which act on the mevalonate pathway by inhibiting HMG-CoA reductase, (b bisphosphonates, which interfere with the isoprenoid pathway in the step catalyzed by farnesyl diphosphate synthase, (c zaragozic acids and quinuclidines, inhibitors of squalene synthase (SQS, which catalyzes the first committed step in sterol biosynthesis, (d allylamines, inhibitors of squalene epoxidase, (e azoles, which inhibit C14α-demethylase, and (f azasterols, which inhibit Δ24(25-sterol methyltransferase (SMT. Inhibition of this last step appears to have high selectivity for fungi and trypanosomatids, since this enzyme is not found in mammalian cells. We review here the IC50 values of these various inhibitors, their effects on the growth of trypanosomatids (both in axenic cultures and in cell cultures, and their effects on protozoan structural organization (as evaluted by light and electron microscopy and lipid composition. The results show that the mitochondrial membrane as well as the membrane lining the protozoan cell body and flagellum are the main targets. Probably as a consequence of these primary effects, other important changes take

  10. Tomato UDP-Glucose Sterol Glycosyltransferases: A Family of Developmental and Stress Regulated Genes that Encode Cytosolic and Membrane-Associated Forms of the Enzyme

    Directory of Open Access Journals (Sweden)

    Karla Ramirez-Estrada

    2017-06-01

    Full Text Available Sterol glycosyltransferases (SGTs catalyze the glycosylation of the free hydroxyl group at C-3 position of sterols to produce sterol glycosides. Glycosylated sterols and free sterols are primarily located in cell membranes where in combination with other membrane-bound lipids play a key role in modulating their properties and functioning. In contrast to most plant species, those of the genus Solanum contain very high levels of glycosylated sterols, which in the case of tomato may account for more than 85% of the total sterol content. In this study, we report the identification and functional characterization of the four members of the tomato (Solanum lycopersicum cv. Micro-Tom SGT gene family. Expression of recombinant SlSGT proteins in E. coli cells and N. benthamiana leaves demonstrated the ability of the four enzymes to glycosylate different sterol species including cholesterol, brassicasterol, campesterol, stigmasterol, and β-sitosterol, which is consistent with the occurrence in their primary structure of the putative steroid-binding domain found in steroid UDP-glucuronosyltransferases and the UDP-sugar binding domain characteristic for a superfamily of nucleoside diphosphosugar glycosyltransferases. Subcellular localization studies based on fluorescence recovery after photobleaching and cell fractionation analyses revealed that the four tomato SGTs, like the Arabidopsis SGTs UGT80A2 and UGT80B1, localize into the cytosol and the PM, although there are clear differences in their relative distribution between these two cell fractions. The SlSGT genes have specialized but still largely overlapping expression patterns in different organs of tomato plants and throughout the different stages of fruit development and ripening. Moreover, they are differentially regulated in response to biotic and abiotic stress conditions. SlSGT4 expression increases markedly in response to osmotic, salt, and cold stress, as well as upon treatment with abscisic

  11. Influence of the sterol aliphatic side chain on membrane properties: a molecular dynamics study.

    Science.gov (United States)

    Robalo, João R; Ramalho, J P Prates; Huster, Daniel; Loura, Luís M S

    2015-09-21

    Following a recent experimental investigation of the effect of the length of the alkyl side chain in a series of cholesterol analogues (Angew. Chem., Int. Ed., 2013, 52, 12848-12851), we report here an atomistic molecular dynamics characterization of the behaviour of methyl-branched side chain sterols (iso series) in POPC bilayers. The studied sterols included androstenol (i-C0-sterol) and cholesterol (i-C8-sterol), as well as four other derivatives (i-C5, i-C10, i-C12 and i-C14-sterol). For each sterol, both subtle local effects and more substantial differential alterations of membrane properties along the iso series were investigated. The location and orientation of the tetracyclic ring system is almost identical in all compounds. Among all the studied sterols, cholesterol is the sterol that presents the best matching with the hydrophobic length of POPC acyl chains, whereas longer-chained sterols interdigitate into the opposing membrane leaflet. In accordance with the experimental observations, a maximal ordering effect is observed for intermediate sterol chain length (i-C5, cholesterol, i-C10). Only for these sterols a preferential interaction with the saturated sn-1 chain of POPC (compared to the unsaturated sn-2 chain) was observed, but not for either shorter or longer-chained derivatives. This work highlights the importance of the sterol alkyl chain in the modulation of membrane properties and lateral organization in biological membranes.

  12. Efficacy and safety of plant stanols and sterols in the control of blood cholesterol levels

    NARCIS (Netherlands)

    Katan, M.B.; Grundy, S.M.; Jones, P.J.H.; Law, M.R.; Miettinen, T.; Paoletti, R.

    2003-01-01

    Foods with plant stanol or sterol esters lower serum cholesterol levels. We summarize the deliberations of 32 experts on the efficacy and safety of sterols and stanols. A meta-analysis of 41 trials showed that intake of 2 g/d of stanols or sterols reduced low-density lipoprotein (LDL) by 10%; higher

  13. 4-Methyl Sterols Regulate Fission Yeast SREBP-Scap under Low Oxygen and Cell Stress*

    Science.gov (United States)

    Hughes, Adam L.; Lee, Chih-Yung S.; Bien, Clara M.; Espenshade, Peter J.

    2008-01-01

    In fission yeast, orthologs of mammalian SREBP and Scap, called Sre1 and Scp1, monitor oxygen-dependent sterol synthesis as a measure of cellular oxygen supply. Under low oxygen conditions, sterol synthesis is inhibited and Sre1 cleavage is activated. However, the sterol signal for Sre1 activation is unknown. In this study, we characterize the sterol signal for Sre1 activation using a combination of Sre1 cleavage assays and gas chromatography sterol analysis. We find that Sre1 activation is regulated by levels of the 4-methyl sterols 24-methylene lanosterol and 4,4-dimethylfecosterol under conditions of low oxygen and cell stress. Both increases and decreases in the level of these ergosterol pathway intermediates induce Sre1 proteolysis in a Scp1-dependent manner. The SREBP ortholog in the pathogenic fungus Cryptococcus neoformans is also activated by high levels of 4-methyl sterols, suggesting that this signal for SREBP activation is conserved among unicellular eukaryotes. Finally, we provide evidence that the sterol sensing domain of Scp1 is important for regulating Sre1 proteolysis. The conserved mutations Y247C, L264F, and D392N in Scp1 that render Scap insensitive to sterols cause constitutive Sre1 activation. These findings indicate that unlike Scap, fission yeast Scp1 responds to 4-methyl sterols and thus shares properties with mammalian HMG-CoA reductase, a sterol sensing domain protein whose degradation is regulated by the 4-methyl sterol lanosterol. PMID:17595166

  14. Free Sterols of the red alga Chondria armata (Kutz.) Okamura

    Digital Repository Service at National Institute of Oceanography (India)

    Govenkar, M.B.; Wahidullah, S.

    The free sterols of the red alga, Chondria armata have been identified by means of NMR, EIMS and GCMS analyses. The mixture contained besides cholesterol, C sub(28) and C sub(29) saturated as well as unsaturated components. The major component...

  15. Minor sterols from the sponge Ircinia ramosa (Killer)

    Digital Repository Service at National Institute of Oceanography (India)

    Parameswaran, P.S.; Naik, C.G.; Das, B.; Kamat, S.Y.

    Three sterols, isolated from the lipid fraction of the sponge Ircinia ramosa were characterised as cholest-5-en-3 beta-ol-7-one (7-oxo cholesterol, 1), cholest 5-23-dien-b beta ol-7-one (7-oxo demosterol, 2) and 24E-ethyl cholest-5-en-3 beta -ol-7...

  16. Shotgun lipidomic analysis of chemically sulfated sterols compromises analytical sensitivity

    DEFF Research Database (Denmark)

    Casanovas, Albert; Hannibal-Bach, Hans Kristian; Jensen, Ole Nørregaard

    2014-01-01

    Fourier transform mass spectrometry (FTMS) for identification and quantification of lipid species [6]. Shotgun lipidomics affords extensive lipidome coverage by combining the analysis of lipid extracts in positive and negative ion mode [1, 3]. Notably, sterols such as cholesterol and ergosterol exhibit...

  17. Sterols from the Lakshadweep sponge, Ircinia ramosa (Killer)

    Digital Repository Service at National Institute of Oceanography (India)

    Parameswaran, P.S.; Naik, C.G.; Das, B.; Kamat, S.Y.

    Four monohydroxy sterols, viz, (22E,24S)-24-methylcholest-5,22-dien-3(beta)-ol (3), cholesterol (4), 24(Xi)-ethylcholesterol (8) and the corresponding Delta super(4)-3 ketones, viz. (22E,24S)-24-methylcholest-4,22-dien-3-one (1), cholest-4-en-3-one...

  18. An Abietane Diterpene and a Sterol from Fungus Phellinus igniarius

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new abietane diterpene 12-hydroxy-7-oxo-5, 8, 11, 13-tetraene-18, 6-abietanolide,together with a new natural sterol stigmasta-7, 22-diene-3β, 5α, 6α-triol have been isolated from the fruiting body of the fungus Phellinus igniarius. Their structures were elucidated by spectroscopic methods including 2D NMR techniques.

  19. Sterols and squalene in apricot (Prunus armeniaca L.) kernel oils: the variety as a key factor.

    Science.gov (United States)

    Rudzińska, Magdalena; Górnaś, Paweł; Raczyk, Marianna; Soliven, Arianne

    2017-01-01

    The profile of sterols and squalene content in oils recovered from the kernels of 15 apricot (Prunus armeniaca L.) varieties were investigated. Nine sterols (campesterol, β-sitosterol, Δ5-avenasterol, 24-methylene-cycloartanol, cholesterol, gramisterol, Δ7-stigmasterol, Δ7-avenasterol and citrostadienol) were identified in apricot kernel oils. The β-sitosterol was the predominant sterol in each cultivar and consisted of 76-86% of the total detected sterols. The content of total sterols and squalene were significantly affected by the variety and ranged between 215.7-973.6 and 12.6-43.9 mg/100 g of oil, respectively.

  20. Increased plant sterol and stanol levels in brain of Watanabe rabbits fed rapeseed oil derived plant sterol or stanol esters

    DEFF Research Database (Denmark)

    Fricke, Christiane B.; Schrøder, Malene; Poulsen, Morten

    2007-01-01

    of these components in brain tissue of homozygous and heterozygous Watanabe rabbits, an animal model for familial hypercholesterolemia. Homozygous animals received either a standard diet, RSO stanol or RSO sterol ester while heterozygous animals were additionally fed with 2 g cholesterol/kg to the respective diet...

  1. Comparative analysis of sterol acquisition in the oomycetes Saprolegnia parasitica and Phytophthora infestans

    Science.gov (United States)

    Dahlin, Paul; Srivastava, Vaibhav; Ekengren, Sophia; McKee, Lauren S.; Bulone, Vincent

    2017-01-01

    The oomycete class includes pathogens of animals and plants which are responsible for some of the most significant global losses in agriculture and aquaculture. There is a need to replace traditional chemical means of controlling oomycete growth with more targeted approaches, and the inhibition of sterol synthesis is one promising area. To better direct these efforts, we have studied sterol acquisition in two model organisms: the sterol-autotrophic Saprolegnia parasitica, and the sterol-heterotrophic Phytophthora infestans. We first present a comprehensive reconstruction of a likely sterol synthesis pathway for S. parasitica, causative agent of the disease saprolegniasis in fish. This pathway shows multiple potential routes of sterol synthesis, and draws on several avenues of new evidence: bioinformatic mining for genes with sterol-related functions, expression analysis of these genes, and analysis of the sterol profiles in mycelium grown in different media. Additionally, we explore the extent to which P. infestans, which causes the late blight in potato, can modify exogenously provided sterols. We consider whether the two very different approaches to sterol acquisition taken by these pathogens represent any specific survival advantages or potential drug targets. PMID:28152045

  2. Sterol biosynthesis is required for heat resistance but not extracellular survival in leishmania.

    Science.gov (United States)

    Xu, Wei; Hsu, Fong-Fu; Baykal, Eda; Huang, Juyang; Zhang, Kai

    2014-10-01

    Sterol biosynthesis is a crucial pathway in eukaryotes leading to the production of cholesterol in animals and various C24-alkyl sterols (ergostane-based sterols) in fungi, plants, and trypanosomatid protozoa. Sterols are important membrane components and precursors for the synthesis of powerful bioactive molecules, including steroid hormones in mammals. Their functions in pathogenic protozoa are not well characterized, which limits the development of sterol synthesis inhibitors as drugs. Here we investigated the role of sterol C14α-demethylase (C14DM) in Leishmania parasites. C14DM is a cytochrome P450 enzyme and the primary target of azole drugs. In Leishmania, genetic or chemical inactivation of C14DM led to a complete loss of ergostane-based sterols and accumulation of 14-methylated sterols. Despite the drastic change in lipid composition, C14DM-null mutants (c14dm(-)) were surprisingly viable and replicative in culture. They did exhibit remarkable defects including increased membrane fluidity, failure to maintain detergent resistant membrane fraction, and hypersensitivity to heat stress. These c14dm(-) mutants showed severely reduced virulence in mice but were highly resistant to itraconazole and amphotericin B, two drugs targeting sterol synthesis. Our findings suggest that the accumulation of toxic sterol intermediates in c14dm(-) causes strong membrane perturbation and significant vulnerability to stress. The new knowledge may help improve the efficacy of current drugs against pathogenic protozoa by exploiting the fitness loss associated with drug resistance.

  3. Distribution of sterols and the sources of pollution in surface sediments of Ulungur lake, Xinjiang.

    Science.gov (United States)

    Yao, Xiaorui; Lu, Jianjiang; Liu, Zilong; Ran, Dan; Huang, Yating

    2013-01-01

    Domestic sewage discharged into lakes brings great pressure to the ecological environment. This study selected sediment from an inland lake as a research object to evaluate pollution of the environment. Eight sterols were used to evaluate the content of pollutants, while the ratios of sterols were used as the index to analyze the sources of pollution. The correlations were analyzed between sterols and total organic carbon (TOC), salinity and particle size. The distribution and composition of sterol compounds were determined in 12 surface sediment samples collected from Ulungur lake. The total concentrations of detected sterols in the sediments ranged from 1.3 to 36.3 μg/g.dw. The most abundant sterol detected was β-sitosterol (STI) with average concentrations of 2.6 μg/g.dw, followed by cholesterol (CHOE), stigmasterol (STIG) and stigmastanol (STAN). The concentration of coprostanol (COP) was between 0.03 and 1.66 μg/g.dw. Through correlation analysis, it was found that there was a significant correlation between fecal sterols and plant sterols. So the plant sterols shall not be neglected in evaluating the sources of pollution for their impact to identify the fecal sources. The study suggests that the composition and distribution of sterols in surface sediment provide useful information for environmental contamination monitoring and assessment in the inland lake.

  4. Sterol Biosynthesis Is Required for Heat Resistance but Not Extracellular Survival in Leishmania

    Science.gov (United States)

    Xu, Wei; Hsu, Fong-Fu; Baykal, Eda; Huang, Juyang; Zhang, Kai

    2014-01-01

    Sterol biosynthesis is a crucial pathway in eukaryotes leading to the production of cholesterol in animals and various C24-alkyl sterols (ergostane-based sterols) in fungi, plants, and trypanosomatid protozoa. Sterols are important membrane components and precursors for the synthesis of powerful bioactive molecules, including steroid hormones in mammals. Their functions in pathogenic protozoa are not well characterized, which limits the development of sterol synthesis inhibitors as drugs. Here we investigated the role of sterol C14α-demethylase (C14DM) in Leishmania parasites. C14DM is a cytochrome P450 enzyme and the primary target of azole drugs. In Leishmania, genetic or chemical inactivation of C14DM led to a complete loss of ergostane-based sterols and accumulation of 14-methylated sterols. Despite the drastic change in lipid composition, C14DM-null mutants (c14dm −) were surprisingly viable and replicative in culture. They did exhibit remarkable defects including increased membrane fluidity, failure to maintain detergent resistant membrane fraction, and hypersensitivity to heat stress. These c14dm − mutants showed severely reduced virulence in mice but were highly resistant to itraconazole and amphotericin B, two drugs targeting sterol synthesis. Our findings suggest that the accumulation of toxic sterol intermediates in c14dm − causes strong membrane perturbation and significant vulnerability to stress. The new knowledge may help improve the efficacy of current drugs against pathogenic protozoa by exploiting the fitness loss associated with drug resistance. PMID:25340392

  5. Sterol biosynthesis is required for heat resistance but not extracellular survival in leishmania.

    Directory of Open Access Journals (Sweden)

    Wei Xu

    2014-10-01

    Full Text Available Sterol biosynthesis is a crucial pathway in eukaryotes leading to the production of cholesterol in animals and various C24-alkyl sterols (ergostane-based sterols in fungi, plants, and trypanosomatid protozoa. Sterols are important membrane components and precursors for the synthesis of powerful bioactive molecules, including steroid hormones in mammals. Their functions in pathogenic protozoa are not well characterized, which limits the development of sterol synthesis inhibitors as drugs. Here we investigated the role of sterol C14α-demethylase (C14DM in Leishmania parasites. C14DM is a cytochrome P450 enzyme and the primary target of azole drugs. In Leishmania, genetic or chemical inactivation of C14DM led to a complete loss of ergostane-based sterols and accumulation of 14-methylated sterols. Despite the drastic change in lipid composition, C14DM-null mutants (c14dm(- were surprisingly viable and replicative in culture. They did exhibit remarkable defects including increased membrane fluidity, failure to maintain detergent resistant membrane fraction, and hypersensitivity to heat stress. These c14dm(- mutants showed severely reduced virulence in mice but were highly resistant to itraconazole and amphotericin B, two drugs targeting sterol synthesis. Our findings suggest that the accumulation of toxic sterol intermediates in c14dm(- causes strong membrane perturbation and significant vulnerability to stress. The new knowledge may help improve the efficacy of current drugs against pathogenic protozoa by exploiting the fitness loss associated with drug resistance.

  6. Differential effects of fenpropimorph and fenhexamid, two sterol biosynthesis inhibitor fungicides, on arbuscular mycorrhizal development and sterol metabolism in carrot roots.

    Science.gov (United States)

    Campagnac, Estelle; Fontaine, Joël; Sahraoui, Anissa Lounès-Hadj; Laruelle, Frédéric; Durand, Roger; Grandmougin-Ferjani, Anne

    2008-12-01

    Sterols composition of transformed carrot roots incubated in presence of increasing concentrations of fenpropimorph (0.02; 0.2; 2mgl(-1)) and fenhexamid (0.02; 0.2; 2; 20mgl(-1)), colonized or not by Glomus intraradices was determined. In mycorrhizal roots treated with fenpropimorph, normal Delta(5)-sterols were replaced by unusual compounds such as 9beta,19-cyclopropylsterols (24-methylpollinastanol), Delta(8,14)-sterols (ergosta-8,14-dienol, stigmasta-8,14-dienol), Delta(8)-sterols (Delta(8) sitosterol) and Delta(7)-sterols (ergosta-7,22-dienol). After application of fenpropimorph, a drastic reduction of the mycorrhizal root growth, root colonization and extraradical fungal development was observed. Application of fenhexamid did not modify sterol profiles and the total colonization of roots. But the arbuscule frequency of the fungal partner was significantly affected. Comparison of the effects caused by the tested fungicides indicates that the usual phytosterols may be involved in symbiosis development. Indeed, observed modifications of root sterols composition could explain the high fenpropimorph toxicity to the AM symbiosis. However, the absence of sterolic modifications in the roots treated with fenhexamid could account for its more limited impact on mycorrhization.

  7. Single particle tracking with sterol modulation reveals the cholesterol-mediated diffusion properties of integrin receptors

    Science.gov (United States)

    Arora, Neha; Syed, Aleem; Sander, Suzanne; Smith, Emily A.

    2014-12-01

    A combination of sterol modulation with cyclodextrins plus fluorescence microscopy revealed a biophysical mechanism behind cholesterol’s influence on the diffusion of a ubiquitous class of receptors called integrins. The heterogeneous diffusion of integrins bound to ligand-coated quantum dots was measured using single particle tracking (SPT), and the ensemble changes in integrin diffusion were measured by fluorescence recovery after photobleaching (FRAP). A 25 ± 1% reduction of membrane cholesterol resulted in three significant changes to the diffusion of ligand-bound αPS2CβPS integrins as measured by SPT. There was a 23% increase in ligand-bound mobile integrins; there was a statistically significant increase in the average diffusion coefficient inside zones of confined diffusion, and histograms of confined integrin trajectories showed an increased frequency in the range of 0.1-1 μm2 s-1 and a decreased frequency in the 0.001-0.1 μm2 s-1 range. No statistical change was measured in the duration of confinement nor the size of confined zones. Restoring the cholesterol-depleted cells with exogenous cholesterol or exogenous epicholesterol resulted in similar diffusion properties. Epicholesterol differs from cholesterol in the orientation of a single hydroxyl group. The ability of epicholesterol to substitute for cholesterol suggests a biophysical mechanism for cholesterol’s effect on integrin diffusion. Influences of bilayer thickness, viscosity and organization are discussed as possible explanations for the measured changes in integrin diffusion when the membrane cholesterol concentration is reduced.

  8. New anti-inflammatory sterols from a gorgonian Pinnigorgia sp.

    Science.gov (United States)

    Su, Yin-Di; Cheng, Ching-Hsiao; Wen, Zhi-Hong; Wu, Yang-Chang; Sung, Ping-Jyun

    2016-07-01

    Chemical investigation on the EtOAc-soluble fraction from the MeOH/DCM extract of a gorgonian Pinnigorgia sp. afforded two new sterols, 11-acetoxy-24S-methyl-3β,5α,6α-trihydroxy-9,11-secocholest-7-en-9-one (1) and 5β,6β-epoxy-(22E,24R)-ergosta-8,22-diene-3β,7β-diol (2). The structures of sterols 1 and 2 were elucidated on the basis of spectroscopic analysis and by comparison of their spectroscopic data with those of related analogues. Both 1 and 2 were shown to significantly inhibit the accumulation of the pro-inflammatory iNOS and COX-2 protein in LPS-stimulated RAW264.7 macrophage cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. The sterols of Cucurbita moschata ("calabacita") seed oil.

    Science.gov (United States)

    Rodriguez, J B; Gros, E G; Bertoni, M H; Cattaneo, P

    1996-11-01

    From the sterol fraction of seed oil from commercial Cucurbita moschata Dutch ("calabacita") delta 5 and delta 7 sterols having saturated and unsaturated side chain were isolated by chromatographic procedures and characterized by spectroscopic (1H and 13C-nuclear magnetic resonance, mass spectrometry) methods. The main components were identified as 24S-ethyl 5 alpha-cholesta-7,22E-dien-3 beta-ol (alpha-spinasterol); 24S-ethyl 5 alpha-cholesta-7,22E,25-trien-3 beta-ol (25-dehydrochondrillasterol); 24S-ethyl 5 alpha-cholesta-7,25-dien-3 beta-ol; 24R-ethyl-cholesta-7-en-3 beta-ol (delta 7-stigmastenol) and 24-ethyl-cholesta-7, 24(28)-dien-3 beta-ol (delta 7,24(28)-stigmastadienol).

  10. The Identification of Two New Sterols from Marine Organism

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two new sterol have been isolated from the South China Sea marine organism. Compound 1 was isolated from the sponge Polymastia sobustia and compound 2 was obtained from the soft coral Sinularia inexplicata. Their structures were established as 3β -hydroxy- stigmast-5en-7-one and 24 - methylene cholestan -3β, 6β, 9α, 19 -tetrol by variety of spectral analysis such as IR, EIMS, 1DNMR, 1H-1H COSY, HMQC, HMBC, NOESY.

  11. [Sterol extracts from Begonia Sinensis Rhizome against respiratory inflammation].

    Science.gov (United States)

    Yao, Yong; Jiang, Wei; Li, Yu-shan

    2015-08-01

    The acute and chronic respiratory tract inflammation models were made to investigate the effect and mechanism of sterol extracts from Begonia Sinensis Rhizome (BSR). The first model of acute lung injury was made with Kunming mice by inhaling cigarette smoke, then the mice were treated with different concentrations of BSR sterol extracts. Lung tissue morphology was detected by HE staining, TNF-alpha/MPO were detected by Elisa, and cPLA2 protein were, detected by Western blotting respectively. Results showed that in model group, lung sheet became real, alveolar space shrank or disappeared, alveolar septum was thickened, plenty of inflammatory cells were infiltrated, capillary blood vessels were congestive and the expression of TNF-α, MPO, cPLA2 increased; after administration, a small amount of inflammatory cells were infiltrated, alveolar septum became obvious, capillary congestion status was significantly relieved and the expression of TNF-α, MPO, cPLA2 decreased (P < 0.05). The second model of chronic respiratory tract inflammation in BALB/c mice with bronchial asthma was induced by OVA, then the mice were treated with different concentrations of BSR sterol extracts. Lung tissue morphology was detected by HE staining, indexes such as IL-4, IL-5, IL-13 were detected by Elisa, and the cPLA2 protein expression was detected by Western blotting respectively. Results showed that in model group, a lot of inflammatory cells around lung vessels and bronchi exuded, bronchial goblet cells proliferated and the expression of IL-4, IL-5, IL-13, cPLA2 increased; after administration, inflammatory and goblet cell hyperplasia reduced, the expression of IL-4, IL-5, IL-13, cPLA2 also decreased (P < 0.05). The above results showed BSR sterol extracts could resist against respiratory inflammation by inhibiting cPLA2 in a dose-dependent manner.

  12. Maintaining cholesterol homeostasis:Sterol regulatory element-binding proteins

    Institute of Scientific and Technical Information of China (English)

    Lutz W. Weber; Meinrad Boll; Andreas Stampfl

    2004-01-01

    The molecular mechanism of how hepatocytes maintain cholesterol homeostasis has become much more transparent with the discovery of sterol regulatory element binding proteins (SREBPs) in recent years. These membrane proteins are members of the basic helix-loop-helix-leucine zipper (bHLHZip) family of transcription factors. They activate the expression of at least 30 genes involved in the synthesis of cholesterol and lipids. SREBPs are synthesized as precursor proteins in the endoplasmic reticulum (ER), where they form a complex with another protein, SREBP cleavage activating protein (SCAP).The SCAP molecule contains a sterol sensory domain. In the presence of high cellular sterol concentrations SCAP confines SREBP to the ER. With low cellular concentrations, SCAP escorts SREBP to activation in the Golgi. There, SREBP undergoes two proteolytic cleavage steps to release the mature, biologically active transcription factor, nuclear SREBP (nSREBP). nSREBP translocates to the nucleus and binds to sterol response elements (SRE) in the promoter/enhancer regions of target genes. Additional transcription factors are required to activate transcription of these genes. Three different SREBPs are known, SREBPs-1a, -1c and -2. SREBP-1a and -1c are isoforms produced from a single gene by alternate splicing. SREBP-2is encoded by a different gene and does not display any isoforms. It appears that SREBPs alone, in the sequence described above, can exert complete control over cholesterol synthesis, whereas many additional factors (hormones,cytokines, etc.) are required for complete control of lipid metabolism. Medicinal manipulation of the SREBP/SCAP system is expected to prove highly beneficial in the management of cholesterol-related disease.

  13. Sterol-Rich Membrane Domains Define Fission Yeast Cell Polarity.

    Science.gov (United States)

    Makushok, Tatyana; Alves, Paulo; Huisman, Stephen Michiel; Kijowski, Adam Rafal; Brunner, Damian

    2016-05-19

    Cell polarization is crucial for the functioning of all organisms. The cytoskeleton is central to the process but its role in symmetry breaking is poorly understood. We study cell polarization when fission yeast cells exit starvation. We show that the basis of polarity generation is de novo sterol biosynthesis, cell surface delivery of sterols, and their recruitment to the cell poles. This involves four phases occurring independent of the polarity factor cdc42p. Initially, multiple, randomly distributed sterol-rich membrane (SRM) domains form at the plasma membrane, independent of the cytoskeleton and cell growth. These domains provide platforms on which the growth and polarity machinery assembles. SRM domains are then polarized by the microtubule-dependent polarity factor tea1p, which prepares for monopolar growth initiation and later switching to bipolar growth. SRM polarization requires F-actin but not the F-actin organizing polarity factors for3p and bud6p. We conclude that SRMs are key to cell polarization.

  14. Distribution of free and glycosylated sterols within Cycas micronesica plants

    Science.gov (United States)

    Marler, Thomas E.; Shaw, Christopher A.

    2010-01-01

    Flour derived from Cycas micronesica seeds was once the dominant source of starch for Guam's residents. Cycad consumption has been linked to high incidence of human neurodegenerative diseases. We determined the distribution of the sterols stigmasterol and β-sitosterol and their derived glucosides stigmasterol β-d-glucoside and β-sitosterol β-d-glucoside among various plant parts because they have been identified in cycad flour and have been shown to elicit neurodegenerative outcomes. All four compounds were common in seeds, sporophylls, pollen, leaves, stems, and roots. Roots contained the greatest concentration of both free sterols, and photosynthetic leaflet tissue contained the greatest concentration of both steryl glucosides. Concentration within the three stem tissue categories was low compared to other organs. Reproductive sporophyll tissue contained free sterols similar to seeds, but greater concentration of steryl glucosides than seeds. One of the glucosides was absent from pollen. Concentration in young seeds was higher than old seeds as reported earlier, but concentration did not differ among age categories of leaf, sporophyll, or vascular tissue. The profile differences among the various tissues within these organs may help clarify the physiological role of these compounds. PMID:20157629

  15. Sterols of Saccharomyces cerevisiae erg6 Knockout Mutant Expressing the Pneumocystis carinii S-Adenosylmethionine:Sterol C-24 Methyltransferase (SAM:SMT)

    Science.gov (United States)

    Kaneshiro, Edna S.; Johnston, Laura Q.; Nkinin, Stephenson W.; Romero, Becky I.; Giner, José-Luis

    2014-01-01

    The AIDS-associated lung pathogen Pneumocystis is classified as a fungus although Pneumocystis has several distinct features such as the absence of ergosterol, the major sterol of most fungi. The P. carinii S-adenosylmethionine:sterol C24-methyltransferase (SAM:SMT) enzyme, coded by the erg6 gene, transfers either one or two methyl groups to the C-24 position of the sterol side chain producing both C28 and C29 24-alkylsterols in approximately the same proportions whereas most fungal SAM:SMT transfer only one methyl group to the side chain. The sterol compositions of wild type Sacchromyces cerevisiae, the erg6 knockout mutant (Δerg6), and Δerg6 expressing the P. carinii or the S. cerevisiae erg6 gene were analyzed by a variety of chromatographic and spectroscopic procedures to examine functional complementation in the yeast expression system. Detailed sterol analyses were obtained using high performance liquid chromatography (HPLC) and proton nuclear magnetic resonance spectroscopy (1H-NMR). The P. carinii SAM:SMT in the Δerg6 restored its ability to produce the C28 sterol ergosterol as the major sterol, and also resulted in low levels of C29 sterols. This indicates that while the P. carinii SAM:SMT in the yeast Δerg6 cells was able to transfer a second methyl group to the side chain, the action of Δ24(28)-sterol reductase (coded by the erg4 gene) in the yeast cells prevented the formation and accumulation of as many C29 sterols as that found in P. carinii. PMID:25230683

  16. 甾体衍生物的合成%SYNTHESIS OF STEROL DERIVATIVES BASED ON STEROL METHYLTRANSFERASE ENZYME

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To study on sterol methytranferase enzyme. METHODS:Target compounds were synthesized from cycloartenoland 24(28)-methylenecycloartenol extracted from γ-oryzanol. RESULTS: 11 sterol derivatives were successfully synthesized. CONCLUSIONS:The target compounds were purified by HPLC and their structures were confirmed by NMR and GC/MS. The methods are simple and operable.%目的:研究甾体甲基化转移酶。方法:从γ-oryzanol提取的cycloartenol和 24(28)-methylenecycloartenol为初始原料合成目标化合物。结果:成功地合成了11个甾体衍生物。结论:目标化合物均经HPLC 纯化;结构均经NMR和GC/MS确证,方法简便易行。

  17. Absence of sterols constrains food quality of cyanobacteria for an invasive freshwater bivalve.

    Science.gov (United States)

    Basen, Timo; Rothhaupt, Karl-Otto; Martin-Creuzburg, Dominik

    2012-09-01

    The accumulation of cyanobacterial biomass may severely affect the performance of aquatic consumers. Here, we investigated the role of sterols in determining the food quality of cyanobacteria for the invasive clam Corbicula fluminea, which has become a common benthic invertebrate in many freshwater ecosystems throughout the world. In standardized growth experiments, juvenile clams were fed mixtures of different cyanobacteria (Anabaena variabilis, Aphanothece clathrata, Synechococcus elongatus) or sterol-containing eukaryotic algae (Cryptomonas sp., Nannochloropsis limnetica, Scenedesmus obliquus). In addition, the cyanobacterial food was supplemented with different sterols. We provide evidence that somatic growth of C. fluminea on cyanobacterial diets is constrained by the absence of sterols, as indicated by a growth-enhancing effect of sterol supplementation. Thus, our findings contribute to our understanding of the consequences of cyanobacterial mass developments for benthic consumers and highlight the importance of considering sterols as potentially limiting nutrients in aquatic food webs.

  18. Functional characterization of a C-4 sterol methyl oxidase from the endomycorrhizal fungus Glomus intraradices.

    Science.gov (United States)

    Oger, Elodie; Ghignone, Stefano; Campagnac, Estelle; Fontaine, Joël; Grandmougin-Ferjani, Anne; Lanfranco, Luisa

    2009-01-01

    Sterols are crucial components of eukaryotic membranes that control membrane fluidity and permeability. They play an important role in cell signaling, polarity and sorting. Since many steps in the pathway are essential, sterol biosynthesis inhibitors (SBI) are widely used as antifungal agents. This work reports the identification and the characterization of a C-4 sterol methyl oxidase (SMO), the first gene involved in the sterol biosynthetic pathway, so far described from an arbuscular mycorrhizal fungus. The sequence, called GintSMO, shows a primary structure, a hydrophobicity profile and a pattern of histidine-rich motifs which are typical of C-4 methyl sterol oxidases. The complementation assay in a Saccharomyces cerevisiae mutant strain demonstrates that GintSMO encodes a functional SMO. Changes in GintSMO transcript levels and in the amount of the sterol precursor squalene were observed in in vitro grown extraradical structures exposed to the fenpropimorph SBI fungicide.

  19. Sterol O-Acyltransferase 2-Driven Cholesterol Esterification Opposes Liver X Receptor-Stimulated Fecal Neutral Sterol Loss.

    Science.gov (United States)

    Warrier, Manya; Zhang, Jun; Bura, Kanwardeep; Kelley, Kathryn; Wilson, Martha D; Rudel, Lawrence L; Brown, J Mark

    2016-02-01

    Statin drugs have proven a successful and relatively safe therapy for the treatment of atherosclerotic cardiovascular disease (CVD). However, even with the substantial low-density lipoprotein (LDL) cholesterol lowering achieved with statin treatment, CVD remains the top cause of death in developed countries. Selective inhibitors of the cholesterol esterifying enzyme sterol-O acyltransferase 2 (SOAT2) hold great promise as effective CVD therapeutics. In mouse models, previous work has demonstrated that either antisense oligonucleotide (ASO) or small molecule inhibitors of SOAT2 can effectively reduce CVD progression, and even promote regression of established CVD. Although it is well known that SOAT2-driven cholesterol esterification can alter both the packaging and retention of atherogenic apoB-containing lipoproteins, here we set out to determine whether SOAT2-driven cholesterol esterification can also impact basal and liver X receptor (LXR)-stimulated fecal neutral sterol loss. These studies demonstrate that SOAT2 is a negative regulator of LXR-stimulated fecal neutral sterol loss in mice.

  20. Sterol regulation of acetyl coenzyme A carboxylase: a mechanism for coordinate control of cellular lipid.

    OpenAIRE

    Lopez, J.M.; Bennett, M K; Sanchez, H B; Rosenfeld, J M; Osborne, T E

    1996-01-01

    Transcription from the housekeeping promoter for the acetyl coenzyme A carboxylase (ACC) gene, which encodes the rate-controlling enzyme of fatty acid biosynthesis, is shown to be regulated by cellular sterol levels through novel binding sites for the sterol-sensitive sterol regulatory element binding protein (SREBP)-1 transcription factor. The position of the SREBP sites relative to those for the ubiquitous auxiliary transcription factor Sp1 is reminiscent of that previously described for th...

  1. [Sources, Migration and Conversion of Dissolved Sterols in Qingmuguan Underground River].

    Science.gov (United States)

    Liang, Zuo-bing; Shen, Li-cheng; Sun, Yu-chuan; Wang, Zun-bo; Jiang, Ze-li; Zhang Mei; LIAO, Yu; Xie, Zheng-lan; Zhang, Yuan-zhu

    2015-11-01

    Water samples were collected from the Qinmuguan underground river from July to November in 2013. By gas chromatography-mass spectrometer (GC-MS), dissolved sterols were quantitatively analyzed. The results show that the average variation content of dissolved sterols ranges from 415 to 629 ng x L(-1), with the increasing migration distance of dissolved sterols in underground river, its contents are decreased. Between the inlet and outlet of Qingmuguan underground river, the average variation contents of dissolved sterol are between 724 and 374 ng x L(-1), and the average variation ratios of the content of stigmasterol with cholesterol range from 0.29 to 0.12. In short, their values are decreased accompanied by the increasing migration distance of underground river. The composing component in dissolved sterols varied differently between July to December, and the main component of dissolved sterols is cholesterin, the ratios of the content of dissolved sterols with cholesterin to the total dissolved sterols range from 37.30% to 94.85%. In addition, the ratios of the content of dissolved sterols with coprostanol to cholesterin, coprostanol to cholesterin are below 0.2 respectively, indicating the water quality of underground river is not contaminated by domestic sewage, but with the passage of time water quality tends to deterioration.

  2. Propiconazole inhibits the sterol 14α-demethylase in Glomus irregulare like in phytopathogenic fungi.

    Science.gov (United States)

    Calonne, Maryline; Sahraoui, Anissa Lounès-Hadj; Campagnac, Estelle; Debiane, Djouher; Laruelle, Frédéric; Grandmougin-Ferjani, Anne; Fontaine, Joël

    2012-04-01

    The increasing concentrations impact (0.02, 0.2 and 2 mg L(-1)) of a Sterol Biosynthesis Inhibitor (SBI) fungicide, propiconazole, was evaluated on development and sterol metabolism of two non-target organisms: mycorrhizal or non-mycorrhizal transformed chicory roots and the arbuscular mycorrhizal fungus (AMF) Glomus irregulare using monoxenic cultures. In this work, we provide the first evidence of a direct impact of propiconazole on the AMF by disturbing its sterol metabolism. A significant decrease in end-products sterols contents (24-methylcholesterol and in 24-ethylcholesterol) was observed concomitantly to a 24-methylenedihydrolanosterol accumulation indicating the inhibition of a key enzyme in sterol biosynthesis pathway, the sterol 14α-demethylase like in phytopathogenic fungi. A decrease in end-product sterol contents in propiconazole-treated roots was also observed suggesting a slowing down of the sterol metabolism in plant. Taken together, our findings suggest that the inhibition of the both AM symbiotic partners development by propiconazole results from their sterol metabolism alterations.

  3. Plant sterols, cholesterol precursors and oxysterols: Minute concentrations-Major physiological effects.

    Science.gov (United States)

    Olkkonen, Vesa M; Gylling, Helena; Ikonen, Elina

    2017-05-01

    Non-cholesterol sterols are present in our body at very low concentrations as compared to cholesterol. Small changes in the structure of sterol molecules confer them highly distinct biological activities. The best-known example are steroid hormones derived from cholesterol. During the past decade, our knowledge of also other biomolecules related to or derived from cholesterol, particularly plant sterols, biosynthetic precursors of cholesterol, and oxysterols, has expanded rapidly. In this review article we recapitulate the latest insights into the properties and physiological activities of these non-cholesterol sterols, as well as their importance in disease processes and potential as diagnostic biomarkers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Impact of ice melting on distribution of particulate sterols in glacial fjords of Chilean Patagonia

    Science.gov (United States)

    Gutiérrez, Marcelo H.; Riquelme, Pablo; Pantoja, Silvio

    2016-04-01

    We analyzed variability in abundance and composition of sterols in waters of the fjord adjacent to glacier Jorge Montt, one of the fastest retreated glaciers in Patagonian Icefields. The study was carried out between August 2012 and November 2013 under different meltwater scenarios. Distribution of sterols in surface and bottom waters was determined by Gas Chromatography coupled to Mass Spectrometry. Sterol concentration ranged from 18 to 1726 ng/L in surface and bottom waters and was positive correlated with chlorophyll-a concentration. Under high melting conditions in austral summer, surface meltwaters showed high concentrations of sterols and were dominated by methylene-cholesterol, a representative sterol of centric diatoms. In the area near open ocean and in austral autumn, winter and spring in proglacial fjord, lower sterol concentrations in surface waters were accompanied by other microalgae sterols and an increase in relative abundance of plant sterols, evidencing a different source of organic matter. In autumn, when high meltwater flux was also evidenced, presence of stanols and an uncommon tri-unsaturated sterol suggests influence of meltwaters in composition of sterols in the downstream fjord. We conclude that ice melting can modify sterol composition by setting conditions for development of a singular phytoplankton population able to thrive in surface meltwater and by carrying glacier organic matter into Patagonian glacial fjords. In projected ice melting scenario, these changes in organic matter quantity and quality can potentially affect availability of organic substrates for heterotrophic activity and trophic status of glacial fjords. This research was funded by COPAS Sur-Austral (PFB-31)

  5. A Novel C30 Sterol from Porana racemosa

    Institute of Scientific and Technical Information of China (English)

    LIBo-Gang; CHENBin; WANGDing-Yong; YEQi; ZHANGGuo-Lin

    2004-01-01

    A novel C30 sterol, (22E, 24ξ)-24-n-propylcholest-7, 22-dien-3β-ol (racemosol, 1), along withscopoletin (2), scopolin (3), umbelliferone (4), methylβ-D-frucopyranoside (5), syringaresinol-4-O-β-D-glucopyranoside (6), quercetin-3-O-β-D-glucopyranoside (7), quercetin-3-O-α-L-rhamnopyranoside (8),eupatilin (9), kaempferol-3-O-β-D-glucopyranoside (10) and (E)-N-2-(2,3-dihydroxyphenyl) ethyl cinnamamide(11), was isolated from the whole plants of Porana racemosa Roxb. Their structures were elucidatedpredominantly by spectral evidence.

  6. Effect of Sterol Structure on Chain Ordering of an Unsaturated Phospholipid: A 2H-NMR Study of POPC/Sterol Membranes

    Science.gov (United States)

    Shaghaghi, Mehran; Thewalt, Jenifer; Zuckermann, Martin

    2012-10-01

    The physical properties of biological membranes are considerably altered by the presence of sterols. In particular, sterols help to maintain the integrity of the cell by adjusting the fluidity of the plasma membrane. Cholesterol is in addition an important component of lipid rafts which are hypothesized to compartmentalize the cell membrane surface thereby making it possible for certain proteins to function. Using 2H-NMR spectroscopy, we studied the effect of a series of different sterols on the chain ordering of POPC, an unsaturated phospholipid present in eukaryotic cell membranes. We were able to assigned specific roles to the structural differences between the sterols by comparing the manner in which they affect the average lipid chain conformation of POPC.

  7. Plant sterol intakes and colorectal cancer risk in the Netherlands : cohort study on diet and cancer

    NARCIS (Netherlands)

    Normén, A.L.; Brants, H.A.M.; Voorrips, L.E.; Andersson, H.A.; Brandt, P.A. van den

    2001-01-01

    Background: Plant sterols in vegetable foods might prevent colorectal cancer. Objective: The objective was to study plant sterol intakes in relation to colorectal cancer risk in an epidemiologic study. Design: The study was performed within the framework of the Netherlands Cohort Study on Diet and C

  8. The biosynthesis, absorption, and origin of cholesterol and plant sterols in the Florida land crab.

    Science.gov (United States)

    Douglass, T S; Connor, W E; Lin, D S

    1981-08-01

    In order to study the biosynthesis, composition, and origin of sterols in the Florida land crabs, Cardisoma guanhumi (Latreille), we fed 17 male crabs either a cholesterol-free or a high cholesterol diet for 2 to 7 weeks. The origin of sterols in these crabs, whether from biosynthesis or from the diet, was determined by tahree procedures: the incorporation of isotopic mevalonate into the cholesterol when the diet was cholesterol-free; the absorption of isotopic cholesterol and sitosterol from the diet; the cholesterol and plant sterol concentrations of hepatopancreas, plasma, and muscle under conditions of cholesterol-free and high cholesterol diets. In addition, the interconversion of cholesterol and sitosterol was investigated. Dietary sterols of plant and animal sources were readily absorbed and provided the major source of sterols for this species of crab. The biosynthesis of cholesterol from mevalonate in this crab was minimal. However, cholesterol was synthesized from dietary sitosterol by dealkylation. Cholesterol and the three plant sterols (24 epsilon-methyl cholesterol, stigmasterol, and sitosterol) were found in the hepatopancreas, plasma, and muscle of the crab. Plant sterols contributed from 9 to 37% of the total sterols in the hepatopancreas, plasma, and muscle of the crabs fed a cholesterol-free diet.

  9. Specific Sterols Required for the Internalization Step of Endocytosis in Yeast

    Science.gov (United States)

    Munn, Alan L.; Heese-Peck, Antje; Stevenson, Brian J.; Pichler, Harald; Riezman, Howard

    1999-01-01

    Sterols are major components of the plasma membrane, but their functions in this membrane are not well understood. We isolated a mutant defective in the internalization step of endocytosis in a gene (ERG2) encoding a C-8 sterol isomerase that acts in the late part of the ergosterol biosynthetic pathway. In the absence of Erg2p, yeast cells accumulate sterols structurally different from ergosterol, which is the major sterol in wild-type yeast. To investigate the structural requirements of ergosterol for endocytosis in more detail, several erg mutants (erg2Δ, erg6Δ, and erg2Δerg6Δ) were made. Analysis of fluid phase and receptor-mediated endocytosis indicates that changes in the sterol composition lead to a defect in the internalization step. Vesicle formation and fusion along the secretory pathway were not strongly affected in the ergΔ mutants. The severity of the endocytic defect correlates with changes in sterol structure and with the abundance of specific sterols in the ergΔ mutants. Desaturation of the B ring of the sterol molecules is important for the internalization step. A single desaturation at C-8,9 was not sufficient to support internalization at 37°C whereas two double bonds, either at C-5,6 and C-7,8 or at C-5,6 and C-8,9, allowed internalization. PMID:10564282

  10. Sterols of the green-pigmented, aberrant plastid dinoflagellate, Lepidodinium chlorophorum (Dinophyceae).

    Science.gov (United States)

    Leblond, Jeffrey D; Lasiter, Andrew D

    2012-01-01

    Lepidodinium chlorophorum is a green-pigmented dinoflagellate with an aberrant, tertiary plastid of chlorophyte ancestry rather than the typical red algal, secondary endosymbiont found in the vast majority of photosynthetic dinoflagellates. To date, only one published study exists on the galactolipids of L. chlorophorum, with nothing known about other lipid classes, including sterols. Our objectives were to examine the sterol composition of L. chlorophorum to determine if it produces any unique sterols with the potential to serve as biomarkers, and to compare it to members of the Chlorophyceae to determine if it has inherited any signature green algal sterols from its chlorophyte-derived endosymbiont. We have found that L. chlorophorum produces 6 sterols, all with a 4α-methyl substituent and none of which are known to occur in the Chlorophyceae. Rather, the sterols produced by L. chlorophorum place it within a group of dinoflagellates that have the common dinoflagellate sterols, dinosterol and dinostanol, as part of their sterol composition. Copyright © 2011 Elsevier GmbH. All rights reserved.

  11. Surfactants and Sterols Concentrations in the Surface Microlayer of the Estuarine Areas of Selangor River, Malaysia

    Science.gov (United States)

    Latif, M. T.; Alsalahi, M. A.; Ali, M. M.; Dominick, D.; Khan, M. F.; Wahid, N. B. A.; Mustaffa, N. I. H.

    2016-02-01

    This study aims to determine the concentration of surfactant and sterols as biomarkers in the surface microlayer (SML) in estuarine areas of the Selangor River, Malaysia. SML samples were collected during different seasons using a rotation drum method. The compositions of surfactants were determined as methylene blue active substances (MBAS) and disulphine blue active substances (DBAS) as anionic and cationic surfactants respectively. The concentration of sterols was determined using a gas chromatography equipped with a flame ionization detector (GC-FID). The results show that the concentrations of surfactants around the estuarine area were dominated by anionic surfactants (MBAS) with average concentrations of 0.39 µmol L-1. .The concentrations of total sterols in the SML ranged from 107.06 to 505.55 ng L-1. The surfactants and total sterol concentrations were found to be higher in the wet season compare to dry season. Cholesterol was found to be the most abundant sterols component in the SML of the Selangor River. The diagnostic ratios of sterols show the influence of natural sources and waste on the contribution of sterols in the SML. Further analysis, using principal component analysis (PCA), showed distinct inputs of sterols derived from human activity (40.58%), terrigenous and plant inputs (22.59%) as well as phytoplankton and marine inputs (17.35%).

  12. The use of the Dhcr7 knockout mouse to accurately determine the origin of fetal sterols

    Science.gov (United States)

    Tint, G. S.; Yu, Hongwei; Shang, Quan; Xu, Guorong; Patel, Shailendra B.

    2006-01-01

    Mice with a targeted mutation of 3β-hydroxysterol Δ7-reductase (Dhcr7) that cannot convert 7-dehydrocholesterol to cholesterol were used to identify the origin of fetal sterols. Because their heterozygous mothers synthesize cholesterol normally, virtually all sterols found in a Dhcr7 knockout fetus having a Δ7 or a Δ8 double bond must have been synthesized by the fetus itself but any cholesterol had to have come from the mother. Early in gestation, most fetal sterols were of maternal origin, but at approximately E13–14, in situ synthesis became increasingly important, and by birth, 55–60% of liver and lung sterols had been made by the fetus. In contrast, at E10–11, upon formation of the blood-brain barrier, the brain rapidly became the source of almost all of its own sterols (90% at birth). New, rapid, de novo sterol synthesis in brain was confirmed by the observation that concentrations of C24,25-unsaturated sterols were low in the brains of all very young fetuses but increased rapidly beginning at approximately E11–12. Reduced activity of sterol C24,25-reductase (Dhcr24) in brain, suggested by the abundance of C24,25-unsaturated compounds, seems to be the result of suppressed Dhcr24 expression. The early fetal brain also appears to conserve cholesterol by keeping cholesterol 24-hydroxylase expression low until approximately E18. PMID:16651660

  13. Effect of plant sterols and tannins on Phytophthora ramorum growth and sporulation

    Science.gov (United States)

    The acquisition of plant sterols, mediated via elicitins, is required for growth and sporulation of Phytophthora spp. In this paper, we looked at the interaction between elicitins, sterols, and tannins. When ground leaf tissue was added to growth media, P. ramorum growth and sporulation was greates...

  14. The sterols isolated from Evening Primrose oil modulate the release of proinflammatory mediators.

    Science.gov (United States)

    Montserrat-de la Paz, Sergio; Fernández-Arche, Angeles; Angel-Martín, María; García-Giménez, María Dolores

    2012-09-15

    Evening Primrose oil is a natural product extracted by cold-pressed from Oenothera biennis L. seeds. The unsaponifiable matter of this oil is an important source of interesting minor compounds, like long-chain fatty alcohols, sterols and tocopherols. In the present study, sterols were isolated from the unsaponifiable matter of Evening Primrose oil, and the composition was identified and quantified by GC and GC-MS. The major components of sterols fraction were β-Sitosterol and campesterol. We investigated the ability of sterols from Evening Primrose oil to inhibit the release of different proinflammatory mediators in vitro by murine peritoneal macrophages stimulated with lipopolysaccharide. Sterols significantly and dose-dependently decreased nitric oxide production. Western blot analysis showed that nitric oxide reduction was a consequence of the inhibition of inducible nitric oxide synthetase expression. Sterols also reduced tumor necrosis factor-α, interleukine 1β and tromboxane B₂. However, sterols did not reduce prostaglandin E₂. The reduction of eicosanoid release was related to the inhibition of cyclooxygenase-2 expression. These results showed that sterols may have a protective effect on some mediators involved in inflammatory damage development, suggesting its potential value as a putative functional component of Evening Primrose oil.

  15. Plasma plant sterols serve as poor markers of cholesterol absorption in man

    NARCIS (Netherlands)

    Jakulj, Lily; Mohammed, Hussein; van Dijk, Theo H.; Boer, Theo; Turner, Scott; Groen, Albert K.; Vissers, Maud N.; Stroes, Erik S. G.

    The validation of the use of plasma plant sterols as a marker of cholesterol absorption is frail. Nevertheless, plant sterol concentrations are routinely used to describe treatment-induced changes in cholesterol absorption. Their use has also been advocated as a clinical tool to tailor

  16. A potential biochemical mechanism underlying the influence of sterol deprivation stress on Caenorhabditis elegans longevity

    Science.gov (United States)

    To investigate the biochemical mechanism for sterol-mediated alteration in aging in Caenorhabditis elegans, we established sterol depletion conditions by treating worms with azacoprostane, which reduced mean lifespan of adult C. elegans by 35%. Proteomic analyses of egg proteins from treated and un...

  17. Sterol ratios as a tool for sewage pollution assessment of river sediments in Serbia.

    Science.gov (United States)

    Matić Bujagić, Ivana; Grujić, Svetlana; Jauković, Zorica; Laušević, Mila

    2016-06-01

    In this work, source pollution tracing of the sediments of the Danube River and its tributaries in Serbia was performed using sterol ratios. Improved liquid chromatography-tandem mass spectrometry method, which enabled complete chromatographic separation of four analytes with identical fragmentation reactions (epicoprostanol, coprostanol, epicholestanol and cholestanol), was applied for the determination of steroid compounds (hormones, human/animal and plant sterols). A widespread occurrence of sterols was identified in all analyzed samples, whereas the only detected hormones were mestranol and 17α-estradiol. A human-sourced sewage marker coprostanol was detected at the highest concentration (up to 1939 ng g(-1)). The ratios between the key sterol biomarkers, as well as the percentage of coprostanol relative to the total sterol amount, were applied with the aim of selecting the most reliable for distinction between human-sourced pollution and the sterols originated from the natural sources in river sediments. The coprostanol/(cholesterol + cholestanol) and coprostanol/epicoprostanol ratios do not distinguish between human and natural sources of sterols in the river sediments in Serbia. The most reliable sterol ratios for the sewage pollution assessment of river sediments in the studied area were found to be coprostanol/(coprostanol + cholestanol), coprostanol/cholesterol and epicoprostanol/coprostanol. For the majority of sediments, human-derived pollution was determined. Two sediment samples were identified as influenced by a combination of human and natural biogenic sources. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Regulation of Sterol Biosynthesis in the Human Fungal Pathogen Aspergillus fumigatus: Opportunities for Therapeutic Development

    Science.gov (United States)

    Dhingra, Sourabh; Cramer, Robert A.

    2017-01-01

    Sterols are a major component of eukaryotic cell membranes. For human fungal infections caused by the filamentous fungus Aspergillus fumigatus, antifungal drugs that target sterol biosynthesis and/or function remain the standard of care. Yet, an understanding of A. fumigatus sterol biosynthesis regulatory mechanisms remains an under developed therapeutic target. The critical role of sterol biosynthesis regulation and its interactions with clinically relevant azole drugs is highlighted by the basic helix loop helix (bHLH) class of transcription factors known as Sterol Regulatory Element Binding Proteins (SREBPs). SREBPs regulate transcription of key ergosterol biosynthesis genes in fungi including A. fumigatus. In addition, other emerging regulatory pathways and target genes involved in sterol biosynthesis and drug interactions provide additional opportunities including the unfolded protein response, iron responsive transcriptional networks, and chaperone proteins such as Hsp90. Thus, targeting molecular pathways critical for sterol biosynthesis regulation presents an opportunity to improve therapeutic options for the collection of diseases termed aspergillosis. This mini-review summarizes our current understanding of sterol biosynthesis regulation with a focus on mechanisms of transcriptional regulation by the SREBP family of transcription factors. PMID:28203225

  19. Applying Clustering and Phylogeny Analysis to Study Dinoflagellates based on Sterol Composition.

    Science.gov (United States)

    Sterol compositions of dinoflagellates have been studied for several decades as a means of assessing whether certain species possess unique chemical biomarkers. However, no attempt has been made to compile the results from numerous studies to examine how sterol compositions may relate to the phylog...

  20. Investigations of the capacity of synthesizing 3β-sterols in mollusca—VI. The biosynthesis and composition of 3β-sterols in the neogastropods Purpura lapillus and Murex brandaris

    NARCIS (Netherlands)

    Voogt, P.A.

    1972-01-01

    1. 1. It is shown that Purpura lapillus and Murex brandaris are capable of synthesizing sterols from mevalonate and acetate. The biosynthesis of sterols from acetate proceeds only at a slow rate. This phenomenon is compared with that observed in Natica cataena. 2. 2. The composition of the sterol m

  1. Investigations of the capacity of synthesizing 3β-sterols in mollusca—VI. The biosynthesis and composition of 3β-sterols in the neogastropods Purpura lapillus and Murex brandaris

    NARCIS (Netherlands)

    Voogt, P.A.

    1972-01-01

    1. 1. It is shown that Purpura lapillus and Murex brandaris are capable of synthesizing sterols from mevalonate and acetate. The biosynthesis of sterols from acetate proceeds only at a slow rate. This phenomenon is compared with that observed in Natica cataena. 2. 2. The composition of the sterol m

  2. Submicellar bile salts stimulate phosphatidylcholine transfer activity of sterol carrier protein 2.

    Science.gov (United States)

    Leonard, A N; Cohen, D E

    1998-10-01

    To explore a potential role for sterol carrier protein 2 (SCP2, also known as non-specific lipid transfer protein) in hepatocellular phospholipid trafficking, we examined the influence of submicellar bile salt concentrations on phosphatidylcholine (PC) transfer activity of SCP2. We measured rate constants for first-order transfer of sn-1 palmitoyl, sn-2 parinaroyl PC, a naturally fluorescent self-quenching phospholipid between model membranes. Purified bovine liver SCP2 promoted transfer of PC from donor to acceptor small unilamellar vesicles. Taurine- and glycine-conjugated bile salts (anionic steroid detergent-like molecules), at concentrations well below their critical micellar concentrations, stimulated PC transfer activity of SCP2 80- to 140-fold. Rate constants increased in proportion to bile salt concentration, temperature, and bile salt-membrane binding affinity. Sodium taurofusidate, a conjugated fungal bile salt analog, also activated PC transfer whereas no effect was observed with the anionic and non-ionic straight chain detergents sodium dodecyl sulfate and octylglucoside, respectively. Thermodynamic and kinetic analyses of PC transfer support a mechanism in which bile salts stimulate SCP2 activity by partitioning into donor vesicles and enhancing membrane association of SCP2. These results imply that under physiological conditions, SCP2 may contribute to hepatocellular selection and transport of biliary PCs.

  3. Plant sterol ester diet supplementation increases serum plant sterols and markers of cholesterol synthesis, but has no effect on total cholesterol levels.

    Science.gov (United States)

    Weingärtner, Oliver; Bogeski, Ivan; Kummerow, Carsten; Schirmer, Stephan H; Husche, Constanze; Vanmierlo, Tim; Wagenpfeil, Gudrun; Hoth, Markus; Böhm, Michael; Lütjohann, Dieter; Laufs, Ulrich

    2017-05-01

    This double-blind, randomized, placebo-controlled, cross-over intervention-study was conducted in healthy volunteers to evaluate the effects of plant sterol ester supplemented margarine on cholesterol, non-cholesterol sterols and oxidative stress in serum and monocytes. Sixteen volunteers, average age 34 years, with no or mild hypercholesterolemia were subjected to a 4 week period of daily intake of 3g plant sterols per day supplied via a supplemented margarine on top of regular eating habits. After a wash-out period of one week, volunteers switched groups. Compared to placebo, a diet supplementation with plant sterols increased serum levels of plant sterols such as campesterol (+0.16±0.19mg/dL, p=0.005) and sitosterol (+0.27±0.18mg/dL, pcholesterol synthesis such as desmosterol (+0.05±0.07mg/dL, p=0.006) as well as lathosterol (+0.11±0.16mg/dL, p=0.012). Cholesterol serum levels, however, were not changed significantly (+18.68±32.6mg/dL, p=0.052). These findings could not be verified in isolated circulating monocytes. Moreover, there was no effect on monocyte activation and no differences with regard to redox state after plant sterol supplemented diet. Therefore, in a population of healthy volunteers with no or mild hypercholesterolemia, consumption of plant sterol ester supplemented margarine results in increased concentrations of plant sterols and cholesterol synthesis markers without affecting total cholesterol in the serum, activation of circulating monocytes or redox state. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Method Development for the Determination of Free and Esterified Sterols in Button Mushrooms (Agaricus bisporus).

    Science.gov (United States)

    Hammann, Simon; Vetter, Walter

    2016-05-04

    Ergosterol is the major sterol in button mushrooms (Agaricus bisporus) and can occur as free alcohol or esterified with fatty acids (ergosteryl esters). In this study, gas chromatography with mass spectrometry in the selected ion monitoring mode (GC/MS-SIM) was used to determine ergosterol and ergosteryl esters as well as other sterols and steryl esters in button mushrooms. Different quality control measures were established and sample preparation procedures were compared to prevent the formation of artifacts and the degradation of ergosteryl esters. The final method was then used for the determination of ergosterol (443 ± 44 mg/100 g dry matter (d.m.)) and esterified ergosterol (12 ± 6 mg/100 g d.m.) in button mushroom samples (n = 4). While the free sterol fraction was vastly dominated by ergosterol (∼90% of five sterols in total), the steryl ester fraction was more diversified (nine sterols in total, ergosterol ∼55%) and consisted primarily of linoleic acid esters.

  5. Fatty acids and sterols of Griffonia seeds oil

    Directory of Open Access Journals (Sweden)

    Ramazanov, Zakir

    2003-03-01

    Full Text Available Lipids, fatty acids and sterols of Griffonia simplicifolia seeds oil were studied. Fatty acid composition is 18:2 - 60 %, 16:0, 18:0, 18:1 - 9-18 %, and 20:0 - 3-4 %. The main sterol is β-sitosterol - 60 %, stigmasterol is 29 %, and campesterol is 11 %. Linoleic acid can be relatively simply enriched to 95 % separating the other fatty acids as urea adducts.Se han estudiado los lípidos, ácidos grasos y esteroles del aceite de semillas de Griffonia simplicifolia. La composición en ácidos grasos es 18:2 – 60 %, 16:0, 18:0, 18:1 – 9-18 %, y 20:0 – 3-4 %. El principal esterol es el β-sitosterol – 60 %, el estigmasterol constituye el 29 %, y el campesterol el 11 %. El ácido linoleico puede enriquecerse hasta el 95 % separando los otros ácidos grasos como aductos de urea.

  6. Cerebral Accumulation of Dietary Derivable Plant Sterols does not Interfere with Memory and Anxiety Related Behavior in Abcg5-/- Mice

    NARCIS (Netherlands)

    T. Vanmierlo (Tim); K. Rutten (Kris); L.C. van Vark-van der Zee (Leonie); S. Friedrichs (Silvia); V.W. Bloks (Vincent ); A. Blokland (Arjan); F.C.S. Ramaekers (Franks); E.J.G. Sijbrands (Eric); H. Steinbusch; J. Prickaerts (Jos); F. Kuipers (Folkert); D. Lütjohann; M. Mulder (Monique)

    2011-01-01

    textabstractPlant sterols such as sitosterol and campesterol are frequently applied as functional food in the prevention of atherosclerosis. Recently, it became clear that plasma derived plant sterols accumulate in murine brains. We questioned whether plant sterols in the brain are associ/+ mice for

  7. Serum lipid and antioxidant responses in hypercholesterolemic men and women receiving plant sterol esters vary by apolipoprotein E genotype

    Science.gov (United States)

    Plant sterol esters reduce serum total cholesterol (TC) and LDL cholesterol (LDL-C), but with striking inter-individual variability. In this randomized, double-blind, controlled study, serum lipid, plant sterol, fat-soluble vitamin, and carotenoid responses to plant sterols were studied according to...

  8. Fecal sterols, seasonal variability, and probable sources along the ring of cenotes, Yucatan, Mexico.

    Science.gov (United States)

    Arcega-Cabrera, F; Velázquez-Tavera, N; Fargher, L; Derrien, M; Noreña-Barroso, E

    2014-11-01

    Rapid development in Yucatan has had a dramatic impact on the environment, especially the water supply. Groundwater is the only source of water in Yucatan, since surface water is virtually absent due to the karstic nature of the soil. The ring of cenotes (RC) is a geological feature which functions as a source of water and as nodes in the underground river system that canalizes water towards the coast. Numerous productive and domestic activities take place around the RC in the absence of wastewater treatment or sewage systems. Consequently, a number of researchers have hypothesized that pollutants could migrate from the land surface to the underlying aquifer and, eventually, to the coast. Therefore, the present study investigates the relationship among sources of fecal sterols and their levels in cenotes, using the expected levels of fecal sterols obtained by a spatial analysis of the sources and a Pollution Source Index. Accordingly, expected levels are compared with the detected levels of fecal sterols in 5 areas around the RC. Regarding levels, observed during a sampling campaign carried out along the RC during September 2011 (rainy season) and May 2012 (dry season), varied from low to high concentrations of sterols (0.5-2396.42 μg g(-1)) and fecal sterols (0.3-1690.18 μg g(-1)). These concentrations showed no relationship between neighboring cenotes, where similar fecal sterol concentrations or gradients were expected. When comparing expected fecal sterols levels with the detected ones, only two of the five analyzed areas concur, suggesting that no clear relationship exists among sources and fecal sterols levels at the regional scale. Multivariate analysis showed that fecal sterols were associated with sterols and fine grain particulates during the rainy season, which suggests co-transport. During the dry season, fecal sterols associated with fine grain particulate and organic matter, which indicates a change to a deposition phenomenon. These findings

  9. Fecal sterols, seasonal variability, and probable sources along the ring of cenotes, Yucatan, Mexico

    Science.gov (United States)

    Arcega-Cabrera, F.; Velázquez-Tavera, N.; Fargher, L.; Derrien, M.; Noreña-Barroso, E.

    2014-11-01

    Rapid development in Yucatan has had a dramatic impact on the environment, especially the water supply. Groundwater is the only source of water in Yucatan, since surface water is virtually absent due to the karstic nature of the soil. The ring of cenotes (RC) is a geological feature which functions as a source of water and as nodes in the underground river system that canalizes water towards the coast. Numerous productive and domestic activities take place around the RC in the absence of wastewater treatment or sewage systems. Consequently, a number of researchers have hypothesized that pollutants could migrate from the land surface to the underlying aquifer and, eventually, to the coast. Therefore, the present study investigates the relationship among sources of fecal sterols and their levels in cenotes, using the expected levels of fecal sterols obtained by a spatial analysis of the sources and a Pollution Source Index. Accordingly, expected levels are compared with the detected levels of fecal sterols in 5 areas around the RC. Regarding levels, observed during a sampling campaign carried out along the RC during September 2011 (rainy season) and May 2012 (dry season), varied from low to high concentrations of sterols (0.5-2396.42 μg g- 1) and fecal sterols (0.3-1690.18 μg g- 1). These concentrations showed no relationship between neighboring cenotes, where similar fecal sterol concentrations or gradients were expected. When comparing expected fecal sterols levels with the detected ones, only two of the five analyzed areas concur, suggesting that no clear relationship exists among sources and fecal sterols levels at the regional scale. Multivariate analysis showed that fecal sterols were associated with sterols and fine grain particulates during the rainy season, which suggests co-transport. During the dry season, fecal sterols associated with fine grain particulate and organic matter, which indicates a change to a deposition phenomenon. These findings indicate

  10. Cholesterol metabolism and serum non-cholesterol sterols: summary of 13 plant stanol ester interventions.

    Science.gov (United States)

    Hallikainen, Maarit; Simonen, Piia; Gylling, Helena

    2014-04-27

    The efficacy and safety of plant stanols added to food products as serum cholesterol lowering agents have been demonstrated convincingly, but their effects on cholesterol metabolism and on serum non-cholesterol sterols is less evaluated. The aim of this study was to assess the validity of serum non-cholesterol sterols and squalene as bioindices of cholesterol synthesis and absorption, and to examine how the individual serum non-cholesterol sterols respond to consumption of plant stanols. We collected all randomized, controlled plant stanol ester (STAEST) interventions in which serum cholestanol, plant sterols campesterol and sitosterol, and at least two serum cholesterol precursors had been analysed. According to these criteria, there was a total of 13 studies (total 868 subjects without lipid-lowering medication; plant stanol doses varied from 0.8 to 8.8 g/d added in esterified form; the duration of the studies varied from 4 to 52 weeks). Serum non-cholesterol sterols were assayed with gas-liquid chromatography, cholesterol synthesis with the sterol balance technique, and fractional cholesterol absorption with the dual continuous isotope feeding method. The results demonstrated that during the control and the STAEST periods, the serum plant sterol/cholesterol- and the cholestanol/cholesterol-ratios reflected fractional cholesterol absorption, and the precursor sterol/cholesterol-ratios reflected cholesterol synthesis. Plant sterol levels were dose-dependently reduced by STAEST so that 2 g of plant stanols reduced serum campesterol/cholesterol-ratio on average by 32%. Serum cholestanol/cholesterol-ratio was reduced less frequently than those of the plant sterols by STAEST, and the cholesterol precursor sterol ratios did not change consistently in the individual studies emphasizing the importance of monitoring more than one surrogate serum marker. Serum non-cholesterol sterols are valid markers of cholesterol absorption and synthesis even during cholesterol

  11. Fluorescence spectroscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2016-01-01

    Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses...

  12. Lipid-lowering Activity of Natural and Semi-Synthetic Sterols and Stanols.

    Science.gov (United States)

    Taha, Dhiaa A; Wasan, Ellen K; Wasan, Kishor M; Gershkovich, Pavel

    2015-01-01

    Consumption of plant sterols/ stanols has long been demonstrated to reduce plasma cholesterol levels. The objective of this review is to demonstrate the lipid-lowering activity and anti-atherogenic effects of natural and semi-synthetic plant sterols/ stanols based on evidence from cell-culture studies, animal studies and clinical trials. Additionally, this review highlights certain molecular mechanisms by which plant sterols/ stanols lower plasma cholesterol levels with a special emphasis on factors that affect the cholesterol-lowering activity of plant sterols/stanols. The crystalline nature and the poor oil solubility of these natural products could be important factors that limit their cholesterol-lowering efficiency. Several attempts have been made to improve the cholesterol-lowering activity by enhancing the bioavailability of crystalline sterols and stanols. Approaches involved reduction of the crystal size and/or esterification with fatty acids from vegetable or fish oils. However, the most promising approach in this context is the chemical modification of plant sterols /stanols into water soluble disodium ascorbyl phytostanyl phosphates analogue by esterification with ascorbic acid. This novel semi-synthetic stanol derivative has improved efficacy over natural plant sterols/ stanols and can provide additional benefits by combining the cholesterol-lowering properties of plant stanols with the antioxidant potential of ascorbic acid. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

  13. An HPLC method for the quantification of sterols in edible seaweeds.

    Science.gov (United States)

    Sánchez-Machado, D I; López-Hernández, J; Paseiro-Losada, P; López-Cervantes, J

    2004-04-01

    This study presents an HPLC method for the quantification of sterols in edible seaweeds. Sterols were identified by HPLC/mass spectrometry (HPLC-MS) in positive APCI mode. The samples were saponified by refluxing with 1 m ethanolic KOH, and the non-saponifiable fraction was extracted with hexane. Sterols were quantified by HPLC with UV detection (HPLC-UV), on a 15 x 0.4 cm Kromasil 100 C(18) 5 micro m column (mobile phase 30:70 v/v methanol:acetonitrile; fl ow rate 1.2 mL/min; column temperature 30 degrees C; detection wavelength 205 nm). Method repeatability for fucosterol was good (coefficient of variation 2.4%). Sterol contents were determined in canned or dried brown seaweeds (Himanthalia elongata, Undaria pinnatifida, Laminaria ochroleuca) and red seaweeds (Palmaria sp., Porphyra sp.). The predominant sterol was fucosterol in brown seaweeds (83-97% of total sterol content; 662-2320 micro g/g dry weight), and desmosterol in red seaweeds (87-93% of total sterol content; 187-337 micro g/g dry weight).

  14. Effects of plant sterols and stanols on intestinal cholesterol metabolism: suggested mechanisms from past to present.

    Science.gov (United States)

    De Smet, Els; Mensink, Ronald P; Plat, Jogchum

    2012-07-01

    Plant sterols and stanols are natural food ingredients found in plants. It was already shown in 1950 that they lower serum low-density lipoprotein cholesterol (LDL-C) concentrations. Meta-analysis has reported that a daily intake of 2.5 g plant sterols/stanols reduced serum LDL-C concentrations up to 10%. Despite many studies, the underlying mechanism remains to be elucidated. Therefore, the proposed mechanisms that have been presented over the past decades will be described and discussed in the context of the current knowledge. In the early days, it was suggested that plant sterols/stanols compete with intestinal cholesterol for incorporation into mixed micelles as well as into chylomicrons. Next, the focus shifted toward cellular processes. In particular, a role for sterol transporters localized in the membranes of enterocytes was suggested. All these processes ultimately lowered intestinal cholesterol absorption. More recently, the existence of a direct secretion of cholesterol from the circulation into the intestinal lumen was described. First results in animal studies suggested that plant sterols/stanols activate this pathway, which also explains the increased fecal neutral sterol content and as such could explain the cholesterol-lowering activity of plant sterols/stanols.

  15. Sterols of the green-pigmented, freshwater raphidophyte, Gonyostomum semen, from Scandinavian lakes.

    Science.gov (United States)

    Leblond, Jeffrey D; Dahmen, Aaron S; Lebret, Karen; Rengefors, Karin

    2013-01-01

    Sterols are a class of membrane-reinforcing, ringed lipids which have a long history of examination in algae as a means of deriving chemotaxonomic relationships and as potential lipidic biomarkers. The Raphidophyceae represent a class of harmful, bloom-forming, marine and freshwater algae. To date, there have been four published examinations of their sterol composition, focusing primarily on brown-pigmented, marine species within the genera, Chattonella, Fibrocapsa, and Heterosigma. Lacking in these examinations has been the species Gonyostomum semen Ehrenb., which is a green-pigmented, freshwater raphidophyte with a worldwide distribution. The goal of this study was to examine the sterol composition of this nuisance alga, determine the potential of using its sterol profile as a biomarker, and finally to determine if there is any intraspecific variability between isolates. We have examined 21 isolates of G. semen from a number of Scandinavian lakes, and all were found to produce two major sterols, 24-ethylcholesta-5,22E-dien-3β-ol and 24-ethylcholest-5-en-3β-ol, and 24-methylcholest-5-en-3β-ol as a minor sterol; the presence of 24-ethylcholesta-5,22E-dien-3β-ol differentiates G. semen from brown-pigmented, marine raphidophytes which generally lack it. The results of this study indicate that isolates of G. semen from geographically separate lakes across Finland and Scandinavia have the same sterol biosynthetic pathway, and that there is no evolutionary divergence between the isolates with regard to sterol composition. The sterols of G. semen are not considered to be useful biomarkers for this particular organism because they are commonly found in other algae and plants. © 2013 The Author(s) Journal of Eukaryotic Microbiology © 2013 International Society of Protistologists.

  16. Zinc finger transcription factors displaced SREBP proteins as the major Sterol regulators during Saccharomycotina evolution.

    Directory of Open Access Journals (Sweden)

    Sarah L Maguire

    2014-01-01

    Full Text Available In most eukaryotes, including the majority of fungi, expression of sterol biosynthesis genes is regulated by Sterol-Regulatory Element Binding Proteins (SREBPs, which are basic helix-loop-helix transcription activators. However, in yeasts such as Saccharomyces cerevisiae and Candida albicans sterol synthesis is instead regulated by Upc2, an unrelated transcription factor with a Gal4-type zinc finger. The SREBPs in S. cerevisiae (Hms1 and C. albicans (Cph2 have lost a domain, are not major regulators of sterol synthesis, and instead regulate filamentous growth. We report here that rewiring of the sterol regulon, with Upc2 taking over from SREBP, likely occurred in the common ancestor of all Saccharomycotina. Yarrowia lipolytica, a deep-branching species, is the only genome known to contain intact and full-length orthologs of both SREBP (Sre1 and Upc2. Deleting YlUPC2, but not YlSRE1, confers susceptibility to azole drugs. Sterol levels are significantly reduced in the YlUPC2 deletion. RNA-seq analysis shows that hypoxic regulation of sterol synthesis genes in Y. lipolytica is predominantly mediated by Upc2. However, YlSre1 still retains a role in hypoxic regulation; growth of Y. lipolytica in hypoxic conditions is reduced in a Ylupc2 deletion and is abolished in a Ylsre1/Ylupc2 double deletion, and YlSre1 regulates sterol gene expression during hypoxia adaptation. We show that YlSRE1, and to a lesser extent YlUPC2, are required for switching from yeast to filamentous growth in hypoxia. Sre1 appears to have an ancestral role in the regulation of filamentation, which became decoupled from its role in sterol gene regulation by the arrival of Upc2 in the Saccharomycotina.

  17. Sterol Lipid Metabolism in Down Syndrome Revisited: Down Syndrome Is Associated with a Selective Reduction in Serum Brassicasterol Levels

    Directory of Open Access Journals (Sweden)

    Gavin Tansley

    2012-01-01

    Full Text Available Over the past 15 years, insights into sterol metabolism have improved our understanding of the relationship between lipids and common conditions such as atherosclerosis and Alzheimer’s Disease (AD. A better understanding of sterol lipid metabolism in individuals with Down Syndrome (DS may help elucidate how this population’s unique metabolic characteristics influence their risks for atherosclerosis and AD. To revisit the question of whether sterol lipid parameters may be altered in DS subjects, we performed a pilot study to assess traditional serum sterol lipids and lipoproteins, as well as markers of sterol biosynthesis, metabolites, and plant sterols in 20 subjects with DS compared to age-matched controls. Here we report that the levels of nearly all lipids and lipoproteins examined are similar to control subjects, suggesting that trisomy 21 does not lead to pronounced general alterations in sterol lipid metabolism. However, the levels of serum brassicasterol were markedly reduced in DS subjects.

  18. Bioactive polyhydroxylated sterols from the marine sponge Haliclona crassiloba.

    Science.gov (United States)

    Cheng, Zhong-Bin; Xiao, Han; Fan, Cheng-Qi; Lu, Ya-Nan; Zhang, Ge; Yin, Sheng

    2013-12-20

    Four new polyhydroxylated sterols, named halicrasterols A-D (1-4), together with six known analogs (5-10) were isolated from the marine sponge Haliclona crassiloba. Compounds 1 and 2 represented rare examples of steroids featuring 17(20)E-double bonds. The structures of 1-10 were elucidated by spectroscopic analysis and comparison with reported data. This is the first report of a steroid profile for this species. The antimicrobial activities of 1-10 were evaluated against a panel of bacterial and fungal strains in vitro, and compounds 4 and 9 showed moderate activity against some of the Gram-positive strains with MICs ranging from 4 to 32 μg/mL. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Synthesis of Molecularly Imprinted Polymer for Sterol Separation

    Directory of Open Access Journals (Sweden)

    Yuangsawad Ratanaporn

    2016-01-01

    Full Text Available Molecular imprinted polymer (MIP was prepared by bulk polymerization in acetone using acrylamide as a functional monomer, ethylene glycol dimethacrylate as a crosslinker, stigmasterol as a template and benzoyl peroxide as an initiator. The obtained MIPs were characterized using a scanning electron microscope and a fourier transform infrared spectrophotometer. Performance in sterol adsorption of MIPs prepared under various conditions was investigated using a model solution of phytosterols in heptane, comparing with a nonimprinted polymer (NIP. Statistical analysis revealed that the amounts of crosslinker and template strongly affected the performance of MIP while the amount of solvent slightly affected the performance of MIP. MIP synthesized under the optimal condition had adsorption capacity of 1.28 mgsterols/gads which were 1.13 times of NIP.

  20. Gas chromatography-mass spectrometry study of sterols from Pinus elliotti tissues.

    Science.gov (United States)

    Laseter, J. L.; Evans, R.; Weete, J. D.; Walkinshaw, C. H.

    1973-01-01

    A comparative study of the sterol components of slash pine (Pinus elliotti) callus tissue cultures, seeds, and seedlings was carried out using GC-MS techniques. Cholesterol, desmosterol, campesterol, stigmasterol, sitosterol and cycloeucalenol were identified in all tissues while lophenol and 24-methylenelophenol were identified in only the seed and seedlings. 24-Ethylidenelophenol was detected in trace concentrations in only the seedlings. Sitosterol was the predominant sterol component, i.e., 80.8, 38.1 and 47.8% of the tissue culture, seed and seedling sterols, respectively.

  1. Bioactive sterols from marine resources and their potential benefits for human health.

    Science.gov (United States)

    Kim, Se-Kwon; Van Ta, Quang

    2012-01-01

    Bioactive agents from marine resources have shown their valuable health beneficial effects. Therefore, increase knowledge on novel functional ingredients with biological activities from marine animal and microbe has gained much attention. Sterols are recognized as potential in development functional food ingredients and pharmaceutical agents. Marine resources, with a great diversity, can be a very interesting natural resource of sterols. This chapter focuses on biological activities of marine animal and microbe sterols with potential health beneficial applications in functional foods and pharmaceuticals. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Distribution and factors affecting adsorption of sterols in the surface sediments of Bosten Lake and Manas Lake, Xinjiang.

    Science.gov (United States)

    Liu, Jiang; Yao, Xiaorui; Lu, Jianjiang; Qiao, Xiuwen; Liu, Zilong; Li, Shanman

    2016-03-01

    This study investigated the concentrations and distribution of eight sterol compounds in the surface sediments of Bosten Lake and Manas Lake, Xinjiang, China. The ratios of sterols as diagnostic indices were used to identify pollution sources. The sediment of the two lakes was selected as an adsorbent to investigate the adsorption behaviour of sterols. Results showed that the sterols were widely distributed in the sediments of the lakes in the study areas. The total concentrations of the detected sterols in Bosten Lake and in Manas Lake were 1.584-27.897 and 2.048-18.373 μg g(-1)∙dw, respectively. In all of the sampling sites, the amount of faecal sterols was less than that of plant sterols. β-sitosterol was the dominant plant sterol with a mean concentration of 2.378 ± 2.234 μg g(-1)∙dw; cholesterol was the most abundant faecal sterol with a mean concentration of 1.060 ± 1.402 μg g(-1)∙dw. The pollution level was higher in Bosten Lake than in Manas Lake. Majority of the ratios clearly demonstrated that the contamination by human faecal sources was occurring at stations which are adjacent to residential areas and water inlets. The adsorption behaviour of sterols to sediment suggested that the sterol adsorption coefficients were reduced as temperature increased. As salinity increased, the adsorption quantity also increased. As pH increased, the sediment adsorption of sterol slightly increased because the strong alkaline solution is not conducive to the adsorption of sterols. The ratios between sterols did not change largely with the change in external factors.

  3. Non-cholesterol Sterols in the Diagnosis and Treatment of Dyslipidemias: A Review.

    Science.gov (United States)

    Baila-Rueda, Lucía; Cenarro, Ana; Civeira, Fernando

    2016-01-01

    Non-cholesterol sterols have been used as markers of cholesterol intestinal absorption and hepatic synthesis, leading to a better understanding of cholesterol homeostasis in humans. This review discusses the main noncholesterol sterols that are clinically useful, different methods to quantify the factors associated with blood concentration, and the potential role of non-cholesterol sterols in the diagnosis and treatment of different types of dyslipidemia. The main indication is the use of non-cholesterol sterols for the diagnosis of rare diseases associated with defects in cholesterol synthesis or anomalies in the absorption and/or elimination of phytosterols. However, other potential uses, including the diagnosis of certain hypercholesterolemias and the individualization of lipid-lowering therapies, are promising as they could help treat a wider population.

  4. Reminiscences of research on the chemistry and biology of natural sterols in insects, plants and humans.

    Science.gov (United States)

    Ikekawa, Nobuo; Fujimoto, Yoshinori; Ishiguro, Masaji

    2013-01-01

    Natural sterols often occur as a heterogeneous mixture of homologs, which had disturbed the progress of steroid research. Development and application of GC methodology overcame this difficulty and enabled us to obtain detailed sterol profiles. Together, fine synthesis of stereo-defined isomers and homologs of steroids having oxygenated side chains allowed us to compare them with natural samples as well as to investigate structure-activity relationship. Advance of HPLC technology also facilitated the determination of the stereochemical structure of naturally occurring steroidal compounds, which were obtained only in minute amounts. This review highlights three topics out of our steroid research that have been performed mainly at Tokyo Institute of Technology around 1970-1990. These are sterol metabolism in insects focusing on the mechanism of the conversion of plant sterols to cholesterol and ecdysone biosynthesis, the synthesis and biochemical research of active forms of vitamin D3 derivatives, and the synthesis and microanalysis of plant hormone brassinosteroids.

  5. Unsaturated lipid matrices protect plant sterols from degradation during heating treatment.

    Science.gov (United States)

    Barriuso, Blanca; Astiasarán, Iciar; Ansorena, Diana

    2016-04-01

    The interest in plant sterols enriched foods has recently enhanced due to their healthy properties. The influence of the unsaturation degree of different fatty acids methyl esters (FAME: stearate, oleate, linoletate and linolenate) on a mixture of three plant sterols (PS: campesterol, stigmasterol and β-sitosterol) was evaluated at 180 °C for up to 180 min. Sterols degraded slower in the presence of unsaturated FAME. Both PS and FAME degradation fit a first order kinetic model (R(2)>0.9). Maximum oxysterols concentrations were achieved at 20 min in neat PS and 120 min in lipid mixtures and this maximum amount decreased with increasing their unsaturation degree. In conclusion, the presence of FAME delayed PS degradation and postponed oxysterols formation. This protective effect was further promoted by increasing the unsaturation degree of FAME. This evidence could help industries to optimize the formulation of sterol-enriched products, so that they could maintain their healthy properties during cooking or processing.

  6. Behavior of plant plasma membranes under hydrostatic pressure as monitored by fluorescent environment-sensitive probes.

    Science.gov (United States)

    Roche, Yann; Klymchenko, Andrey S; Gerbeau-Pissot, Patricia; Gervais, Patrick; Mély, Yves; Simon-Plas, Françoise; Perrier-Cornet, Jean-Marie

    2010-08-01

    We monitored the behavior of plasma membrane (PM) isolated from tobacco cells (BY-2) under hydrostatic pressures up to 3.5kbar at 30 degrees C, by steady-state fluorescence spectroscopy using the newly introduced environment-sensitive probe F2N12S and also Laurdan and di-4-ANEPPDHQ. The consequences of sterol depletion by methyl-beta-cyclodextrin were also studied. We found that application of hydrostatic pressure led to a marked decrease of hydration as probed by F2N12S and to an increase of the generalized polarization excitation (GPex) of Laurdan. We observed that the hydration effect of sterol depletion was maximal between 1 and 1.5 kbar but was much less important at higher pressures (above 2 kbar) where both parameters reached a plateau value. The presence of a highly dehydrated gel state, insensitive to the sterol content, was thus proposed above 2.5 kbar. However, the F2N12S polarity parameter and the di-4-ANEPPDHQ intensity ratio showed strong effect on sterol depletion, even at very high pressures (2.5-3.5 kbar), and supported the ability of sterols to modify the electrostatic properties of membrane, notably its dipole potential, in a highly dehydrated gel phase. We thus suggested that BY-2 PM undergoes a complex phase behavior in response to the hydrostatic pressure and we also emphasized the role of phytosterols to regulate the effects of high hydrostatic pressure on plant PM.

  7. Characterization, mutagenesis and mechanistic analysis of an ancient algal sterol C24-methyltransferase: Implications for understanding sterol evolution in the green lineage.

    Science.gov (United States)

    Haubrich, Brad A; Collins, Emily K; Howard, Alicia L; Wang, Qian; Snell, William J; Miller, Matthew B; Thomas, Crista D; Pleasant, Stephanie K; Nes, W David

    2015-05-01

    Sterol C24-methyltransferases (SMTs) constitute a group of sequence-related proteins that catalyze the pattern of sterol diversity across eukaryotic kingdoms. The only gene for sterol alkylation in green algae was identified and the corresponding catalyst from Chlamydomonas reinhardtii (Cr) was characterized kinetically and for product distributions. The properties of CrSMT were similar to those predicted for an ancient SMT expected to possess broad C3-anchoring requirements for substrate binding and formation of 24β-methyl/ethyl Δ(25(27))-olefin products typical of primitive organisms. Unnatural Δ(24(25))-sterol substrates, missing a C4β-angular methyl group involved with binding orientation, convert to product ratios in favor of Δ(24(28))-products. Remodeling the active site to alter the electronics of Try110 (to Leu) results in delayed timing of the hydride migration from methyl attack of the Δ(24)-bond, that thereby produces metabolic switching of product ratios in favor of Δ(25(27))-olefins or impairs the second C1-transfer activity. Incubation of [27-(13)C]lanosterol or [methyl-(2)H3]SAM as co-substrates established the CrSMT catalyzes a sterol methylation pathway by the "algal" Δ(25(27))-olefin route, where methylation proceeds by a conserved SN2 reaction and de-protonation proceeds from the pro-Z methyl group on lanosterol corresponding to C27. This previously unrecognized catalytic competence for an enzyme of sterol biosynthesis, together with phylogenomic analyses, suggest that mutational divergence of a promiscuous SMT produced substrate- and phyla-specific SMT1 (catalyzes first biomethylation) and SMT2 (catalyzes second biomethylation) isoforms in red and green algae, respectively, and in the case of SMT2 selection afforded modification in reaction channeling necessary for the switch in ergosterol (24β-methyl) biosynthesis to stigmasterol (24α-ethyl) biosynthesis during the course of land plant evolution.

  8. Determining Antifungal Target Sites in the Sterol Pathway of the Yeasts Candida and Saccharomyces

    Science.gov (United States)

    1999-10-01

    earliest convenience to discuss this draft. With kind regards, Gregory J. Hanson Paralegal Enclosure Patent Protection for High Technol DNA ENCODING...an isolated nucleic acid segment comprising a nucleic acid sequence encoding a Candida albicans sterol methyltransferase (ERG6), a biologically active... biologically active variant or subunit thereof, e.g., a polypeptide having SEQ ID 15 NO:2. Methods to isolate and purify sterol methyltransferase are known

  9. Enhanced Membrane Fusion in Sterol-enriched Vacuoles Bypasses the Vrp1p RequirementD⃞

    OpenAIRE

    Tedrick, Kelly; Trischuk, Tim; Lehner, Richard; Eitzen, Gary

    2004-01-01

    Organization of lipids into membrane microdomains is a vital mechanism of protein processing. Here we show that overexpression of ERG6, a gene involved in ergosterol synthesis, elevates sterol levels 1.5-fold on the vacuole membrane and enhances their homotypic fusion. The mechanism of sterol-enhanced fusion is not via more efficient sorting, but instead promotes increased kinetics of fusion subreactions. We initially isolated ERG6 as a suppressor of a vrp1Δ growth defect selective for vacuol...

  10. Enhanced Membrane Fusion in Sterol-enriched Vacuoles Bypasses the Vrp1p RequirementD⃞

    OpenAIRE

    Tedrick, Kelly; Trischuk, Tim; Lehner, Richard; Eitzen, Gary

    2004-01-01

    Organization of lipids into membrane microdomains is a vital mechanism of protein processing. Here we show that overexpression of ERG6, a gene involved in ergosterol synthesis, elevates sterol levels 1.5-fold on the vacuole membrane and enhances their homotypic fusion. The mechanism of sterol-enhanced fusion is not via more efficient sorting, but instead promotes increased kinetics of fusion subreactions. We initially isolated ERG6 as a suppressor of a vrp1Δ growth defect selective for vacuol...

  11. Sterol Distribution in Sediments from Chaiwobu Lake and Caohai Basin and Its Geochemical Significance

    Institute of Scientific and Technical Information of China (English)

    史继扬; 林树基; 等

    1994-01-01

    In order to understand the distribution characteristics of biomarkers in source rocks,which may be related to organic input,Quaternary sediments from the Caohai Basin and the Chaiwobu Lake were analyzed for sterols,As a result,various sterols,have been found in the sediments.The composition of sterols in the sediments revealed that cholesterols and cholestadienols are more abundant than their C29 counterparts in the Chaiwobu Lake sediments and that C29 sterols are more abundant in the peats from the Caohai Basin,It is also found that stanol/sterol ratios in clays are higher than in peats.Studies show that organic input to the Chaiwobu Lake is mainly plankton and zooplankton and to the Caohai Basin is mainly terrestrial high plant.The authors have proposed that the relative abundance of C27 or C29 sterane in source rocks may reflect input characteristics to some extent and the stanol/sterol ratios may reflect the redox conditions of the depositional environments.

  12. Sterol metabolism in the filasterean Capsaspora owczarzaki has features that resemble both fungi and animals

    Science.gov (United States)

    Molina, María Celeste; Ruiz-Trillo, Iñaki; Uttaro, Antonio D.

    2016-01-01

    Sterols are essential for several physiological processes in most eukaryotes. Sterols regulate membrane homeostasis and participate in different signalling pathways not only as precursors of steroid hormones and vitamins, but also through its role in the formation of lipid rafts. Two major types of sterols, cholesterol and ergosterol, have been described so far in the opisthokonts, the clade that comprise animals, fungi and their unicellular relatives. Cholesterol predominates in derived bilaterians, whereas ergosterol is what generally defines fungi. We here characterize, by a combination of bioinformatic and biochemical analyses, the sterol metabolism in the filasterean Capsaspora owczarzaki, a close unicellular relative of animals that is becoming a model organism. We found that C. owczarzaki sterol metabolism combines enzymatic activities that are usually considered either characteristic of fungi or exclusive to metazoans. Moreover, we observe a differential transcriptional regulation of this metabolism across its life cycle. Thus, C. owczarzaki alternates between synthesizing 7-dehydrocholesterol de novo, which happens at the cystic stage, and the partial conversion—via a novel pathway—of incorporated cholesterol into ergosterol, the characteristic fungal sterol, in the filopodial and aggregative stages. PMID:27383626

  13. In Vitro and In Vivo Anticancer Effects of Sterol Fraction from Red Algae Porphyra dentata

    Directory of Open Access Journals (Sweden)

    Katarzyna Kazłowska

    2013-01-01

    Full Text Available Porphyra dentata, an edible red macroalgae, is used as a folk medicine in Asia. This study evaluated in vitro and in vivo the protective effect of a sterol fraction from P. dentata against breast cancer linked to tumor-induced myeloid derived-suppressor cells (MDSCs. A sterol fraction containing cholesterol, β-sitosterol, and campesterol was prepared by solvent fractionation of methanol extract of P. dentata  in silica gel column chromatography. This sterol fraction in vitro significantly inhibited cell growth and induced apoptosis in 4T1 cancer cells. Intraperitoneal injection of this sterol fraction at 10 and 25 mg/kg body weight into 4T1 cell-implanted tumor BALB/c mice significantly inhibited the growth of tumor nodules and increased the survival rate of mice. This sterol fraction significantly decreased the reactive oxygen species (ROS and arginase activity of MDSCs in tumor-bearing mice. Therefore, the sterol fraction from P. dentata showed potential for protecting an organism from 4T1 cell-based tumor genesis.

  14. Quantitation of fatty acids, sterols, and tocopherols in turpentine (Pistacia terebinthus Chia) growing wild in Turkey.

    Science.gov (United States)

    Matthäus, Bertrand; Ozcan, Mehmet Musa

    2006-10-04

    The chemical composition (fatty acids, tocopherols, and sterols) of the oil from 14 samples of turpentine (Pistacia terebinthus L.) fruits is presented in this study. The oil content of the samples varied in a relatively small range between 38.4 g/100 g and 45.1 g/100 g. The dominating fatty acid of the oil is oleic acid, which accounted for 43.0 to 51.3% of the total fatty acids. The total content of vitamin E active compounds in the oils ranged between 396.8 and 517.7 mg/kg. The predominant isomers were alpha- and gamma-tocopherol, with approximate equal amounts between about 110 and 150 mg/kg. The seed oil of P. terebinthus also contained different tocotrienols, with gamma-tocotrienol as the dominate compound of this group, which amounted to between 79 and 114 mg/kg. The total content of sterols of the oils was determined to be between 1341.3 and 1802.5 mg/kg, with beta-sitosterol as the predominent sterol that accounted for more than 80% of the total amount of sterols. Other sterols in noteworthy amounts were campesterol, Delta5-avenasterol, and stigmasterol, which came to about 3-5% of the total sterols.

  15. Glyceride structure and sterol composition of SOS-7 halophyte oil

    Directory of Open Access Journals (Sweden)

    El-Shami, S. M.

    1991-06-01

    Full Text Available Glyceride structure of SOS-7 halophyte oil was studied using the lipase hydrolysis technique. This halophyte sample was obtained from 1988 harvest planted in Ghardaka, on the border of the Red Sea, Egypt. The oilseed was ground and extracted for its oil using commercial hexane in Soxhlet extractor. The unsaturated fatty acids were found centralized in the 2-position of triglycerides, whereas oleic and linolenic acids showed more preference for this position. It was found that P3 was the major component of GS3, whereas P2L and PStL; PL2, POL and StL2 are predominating among GS2U and GSU3 respectively. L3 manifested itself as the principal constituent of GU3 type. Sterol composition of the halophyte oil was determined by GLC as TMS derivative. It was found that the oil contains campsterol, β-sitosterol, stigmasterol and 7-stigmasterol of which 7-stigmasterol is the major sterol and constitute 52.4%.

    Se ha estudiado usando la técnica de hidrólisis mediante lipasa la estructura glicerídica de aceite de halofito SOS-7. Esta muestra de halofito fue obtenida a partir de una cosecha de 1988 plantada en Ghardaka, en la orilla del Mar Rojo, Egipto. Para la extracción del aceite de la semilla molida se utilizó hexano comercial en extractor Soxhlet. Los ácidos grasos insaturados se encontraron centralizados en la posición 2 de los triglicéridos, siendo los ácidos oleico y linolénico los que mostraron mayor preferencia por esta posición. Se encontró que P3 fue el componente mayoritario de GS3, mientras que P2L y PStL; PL2 POL y StL2 son los predominantes para GS2U y GSU3 respectivamente. L3 se manifestó como el principal constituyente de los GU3. La composición esterólica del aceite de halofito se determinó por GLC como derivados del

  16. Effects of seaweed sterols fucosterol and desmosterol on lipid membranes

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Bagatolli, Luis A.; Duelund, Lars

    2017-01-01

    techniques, including calorimetry, fluorescence microscopy, vesicle-fluctuation analysis, and atomic force microscopy, we have found that fucosterol and desmosterol, found in red and brown macroalgae (seaweeds), similar to cholesterol support liquid-ordered membrane phases and induce coexistence between...

  17. Faecal sterols as indicators of sewage contamination in estuarine sediments of the Tay Estuary, Scotland: an extended baseline survey

    Science.gov (United States)

    Reeves, A. D.; Patton, D.

    2005-06-01

    Sterol ratios are used to identify sources, occurrence and partitioning of faecal matter in sediments of the Tay Estuary, Scotland. The 5β/(5α+5β) ratio is used to discriminate between sewage and biogenic sterol sources by comparing the concentrations of coprostanols to cholesterol plus coprostanols. This index shows unambiguous sewage pollution in the Invergowrie Bay area (values >0.7). The coprostanol/epicoprostanol index is used to differentiate between human and non-human faecal inputs. Ratios confirmed the primary source as human-derived faecal material. The coprostanol/cholesterol ratio was calculated in order to elucidate the contribution of different biogenic sources to the sedimentary sterol budget. Ratios of >1 clearly indicate faecal sterol sources. Invergowrie Bay displayed no sterol signature other than sewage. A biogenic source of cholesterol influenced total sterol concentrations upstream of the City of Dundee. Attention is directed to the potential role of density fronts in compartmentalization of faecal material in bottom sediments.

  18. Nuclear envelope remnants: fluid membranes enriched in sterols and polyphosphoinositides.

    Directory of Open Access Journals (Sweden)

    Marie Garnier-Lhomme

    Full Text Available BACKGROUND: The cytoplasm of eukaryotic cells is a highly dynamic compartment where membranes readily undergo fission and fusion to reorganize the cytoplasmic architecture, and to import, export and transport various cargos within the cell. The double membrane of the nuclear envelope that surrounds the nucleus, segregates the chromosomes from cytoplasm and regulates nucleocytoplasmic transport through pores. Many details of its formation are still unclear. At fertilization the sperm devoid of nuclear envelope pores enters the egg. Although most of the sperm nuclear envelope disassembles, remnants of the envelope at the acrosomal and centriolar fossae do not and are subsequently incorporated into the newly forming male pronuclear envelope. Remnants are conserved from annelid to mammalian sperm. METHODOLOGY/PRINCIPAL FINDINGS: Using lipid mass spectrometry and a new application of deuterium solid-state NMR spectroscopy we have characterized the lipid composition and membrane dynamics of the sperm nuclear envelope remnants in isolated sperm nuclei. CONCLUSIONS/SIGNIFICANCE: We report nuclear envelope remnants are relatively fluid membranes rich in sterols, devoid of sphingomyelin, and highly enriched in polyphosphoinositides and polyunsaturated phospholipids. The localization of the polybasic effector domain of MARCKS illustrates the non-nuclear aspect of the polyphosphoinositides. Based on their atypical biophysical characteristics and phospholipid composition, we suggest a possible role for nuclear envelope remnants in membrane fusion leading to nuclear envelope assembly.

  19. Phase behaviour of sterols and vitamins in supercritical CO2

    Directory of Open Access Journals (Sweden)

    Gerszt R.

    2000-01-01

    Full Text Available Extraction with supercritical solvents has been used in different areas, such as petroleum desasphaltation, descaffeination of coffee and tea and in the separation of other types of natural products. The supercritical solvent most frequently utilized in the extraction of natural products is carbon dioxide (CO2 due to its several advantages over other solvents such as low cost, atoxicity and volatility. The design, evaluation and optimization of a supercritical extraction that is based on phase equilibrium require phase equilibrium data. This type of data is very scarce for natural compounds like sterols and vitamins. These natural compounds are produced synthetically, but nowadays interest in their extraction from natural sources is increasing. Therefore, the objective of this work is to study the thermodynamic modelling equilibrium of systems containing vitamins A, D, E and K, using the predictive LCVM model. The sensitivity of critical properties in the calculation of the phase behavior was also studied. This study proved that the choice of a group contribution method to calculate thermodynamic properties is very important for obtaining good results in the phase equilibrium calculations.

  20. Influence of cholesterol and ergosterol on membrane dynamics: a fluorescence approach.

    Science.gov (United States)

    Arora, Ajuna; Raghuraman, H; Chattopadhyay, Amitabha

    2004-06-11

    Sterols are essential membrane components of eukaryotic cells and are important for membrane organization and function. Cholesterol is the most representative sterol present in higher eukaryotes. It is often found distributed non-randomly in domains or pools in biological and model membranes. Cholesterol-rich functional microdomains (lipid rafts) are often implicated in cell signaling and membrane traffic. Interestingly, lipid rafts have also recently been isolated from organisms such as yeast and Drosophila, which have ergosterol as their major sterol component. Although detailed biophysical characterization of the effect of cholesterol on membranes is well documented, the effect of ergosterol on the organization and dynamics of membranes is not very clear. We have monitored the effect of cholesterol and ergosterol on the dynamic properties of both fluid (POPC) and gel (DPPC) phase membranes utilizing the environment-sensitive fluorescent membrane probe DPH. Our results from steady state and time-resolved fluorescence measurements show, for the first time, differential effects of ergosterol and cholesterol toward membrane organization. These novel results are relevant in the context of lipid rafts in ergosterol-containing organisms such as Drosophila which maintain a low level of sterol compared to higher eukaryotes.

  1. Postprandial plasma oxyphytosterol concentrations after consumption of plant sterol or stanol enriched mixed meals in healthy subjects.

    Science.gov (United States)

    Baumgartner, Sabine; Mensink, Ronald P; Konings, Maurice; Schött, Hans-F; Friedrichs, Silvia; Husche, Constanze; Lütjohann, Dieter; Plat, Jogchum

    2015-07-01

    Epidemiological studies have reported inconsistent results on the relationship between increased plant sterol concentrations with cardiovascular risk, which might be related to the formation of oxyphytosterols (plant sterol oxidation products) from plant sterols. However, determinants of oxyphytosterol formation and metabolism are largely unknown. It is known, however, that serum plant sterol concentrations increase after daily consumption of plant sterol enriched products, while concentrations decrease after plant stanol consumption. Still, we have earlier reported that fasting oxyphytosterol concentrations did not increase after consuming a plant sterol- or a plant stanol enriched margarine (3.0g/d of plant sterols or stanols) for 4weeks. Since humans are in a non-fasting state for most part of the day, we have now investigated effects on oxyphytosterol concentrations during the postprandial state. For this, subjects consumed a shake (50g of fat, 12g of protein, 67g of carbohydrates), containing no, or 3.0g of plant sterols or plant stanols. Blood samples were taken up to 8h and after 4h subjects received a second shake (without plant sterols or plant stanols). Serum oxyphytosterol concentrations were determined in BHT-enriched EDTA plasma via GC-MS/MS. 7β-OH-campesterol and 7β-OH-sitosterol concentrations were significantly higher after consumption of a mixed meal enriched with plant sterol esters compared to the control and plant stanol ester meal. These increases were seen only after consumption of the second shake, illustrative for a second meal effect. Non-oxidized campesterol and sitosterol concentrations also increased after plant sterol consumption, in parallel with 7β-OH concentrations and again only after the second meal. Apparently, plant sterols and oxyphytosterols follow the same second meal effect as described for dietary cholesterol. However, the question remains whether the increase in oxyphytosterols in the postprandial phase is due to

  2. Sterol Lipid Metabolism in Down Syndrome Revisited: Down Syndrome Is Associated with a Selective Reduction in Serum Brassicasterol Levels

    OpenAIRE

    2012-01-01

    Over the past 15 years, insights into sterol metabolism have improved our understanding of the relationship between lipids and common conditions such as atherosclerosis and Alzheimer’s Disease (AD). A better understanding of sterol lipid metabolism in individuals with Down Syndrome (DS) may help elucidate how this population’s unique metabolic characteristics influence their risks for atherosclerosis and AD. To revisit the question of whether sterol lipid parameters may be altered in DS subje...

  3. Formation of Plant Sterol Oxidation Products in Foods during Baking and Cooking Using Margarine without and with Added Plant Sterol Esters

    NARCIS (Netherlands)

    Lin, Y.; Knol, D.; Menéndez-Carreño, M.; Blom, W.A.M.; Matthee, J.; Janssen, H.G.; Trautwein, E.A.

    2016-01-01

    Plant sterols (PS) in foods are subject to thermal oxidation to form PS oxidation products (POP). This study measured POP contents of 19 foods prepared by typical household baking and cooking methods using margarines without (control) and with 7.5% added PS (as 12.5% PS-esters, PS-margarine). Median

  4. Formation of Plant Sterol Oxidation Products in Foods during Baking and Cooking Using Margarine without and with Added Plant Sterol Esters

    NARCIS (Netherlands)

    Lin, Y.; Knol, D.; Menéndez-Carreño, M.; Blom, W.A.M.; Matthee, J.; Janssen, H.G.; Trautwein, E.A.

    2016-01-01

    Plant sterols (PS) in foods are subject to thermal oxidation to form PS oxidation products (POP). This study measured POP contents of 19 foods prepared by typical household baking and cooking methods using margarines without (control) and with 7.5% added PS (as 12.5% PS-esters, PS-margarine). Median

  5. Distribution of fecal sterols in surface sediment of Sungai Tebrau, Johor

    Science.gov (United States)

    Nordin, N.; Ali, M. M.

    2013-11-01

    Decreasing quality of aquatic environments may harm human health in general. Sewage pollution from human and animal excretions is a major cause of environmental quality depletion. This study investigates the distribution of sewage contamination level in twenty surface sediment samples taken from Sungai Tebrau, Johor. Four principal fecal sterols have been identified and were found in all sediment samples, which are coprostanol, cholesterol, epicoprostanol and also cholestanol. Cholesterol as the major sterol and most abundant compound derived from a variety of sources ranged from 32.92 to 1,100.55 ngg-1 dry weights. Meanwhile, major fecal sterol, coprostanol has the lowest quantity of total sterol in all samples, constituting only 13% of total sterol. It ranged from 12.63 to 565.42 ngg-1 dry weights, but only two stations (ST12 and ST14) are sewage contaminated. Squatters and residential areas are a major contributor of poorly treated sewage into the aquatic environment. Coprostanol concentration alone is not reliable to indicate sewage contamination; diagnostic indices enhance reliability of sterols as a marker for sewage contamination. Indices applied in this study are coprostanol/cholesterol, coprostanol/(coprostanol+cholestanol) and also epicoprostanol/coprostanol. Resultsof coprostanol/cholesterol, coprostanol/(coprostanol+cholestanol) indices supported the findings that both ST12 and ST14 samples are contaminated with sewage. All samples consist of relativelyhigh concentration of epicoprostanol and high ratio value of epicoprostanol/coprostanol. Generally, it can be concluded that these sampling sites are not contaminated with sewage even though fecal sterols were detected in all samples as they were found to be at low concentration.

  6. Antiproliferative effect of polyphenols and sterols of virgin argan oil on human prostate cancer cell lines.

    Science.gov (United States)

    Bennani, H; Drissi, A; Giton, F; Kheuang, L; Fiet, J; Adlouni, A

    2007-01-01

    The aim of our study has to evaluate the antiproliferative effect of polyphenols and sterols extracted from the virgin argan oil on three human prostatic cell lines (DU145, LNCaP, and PC3). Cytotoxicity, anti-proliferative effects and nuclear morphological changes of cells were analyzed after treatment with sterols and polyphenols. The results were compared to 2-methoxyestradiol (2ME(2)) as positive control. Polyphenols and sterols of virgin argan oil and 2ME(2) exhibited a dose-response cytotoxic effect and antiproliferative action on the three tested cell lines. The antiproliferative effect of polyphenols was similar for the DU145 and LNCaP cell lines; the GI(50) (defined as the concentration inhibiting growth by 50% in comparison with the control) was respectively 73 and 70microg/ml. The antiproliferative effect of sterols was 46 and 60microg/ml as GI(50) for the DU145 and LNCaP cell lines. For the PC3 cell line, the best antiproliferative effect was obtained by argan sterols with GI(50)=43microg/ml. On the other hand, the nuclear morphology analyses have shown an increased proportion of pro-apoptotic of nuclei in LNCaP cell treated with IC(50) of polyphenols or sterols compared to control cells. Our results show for the first time the antiproliferative and pro-apoptotic effects of polyphenols and sterols extracted from virgin argan oil and confirm the antiproliferative and pro-apoptotic effects of 2ME(2) on prostate cancer cell lines. These data suggest that argan oil may be interesting in the development of new strategies for prostate cancer prevention.

  7. Changes in the Sterol Composition of the Plasma Membrane Affect Membrane Potential, Salt Tolerance and the Activity of Multidrug Resistance Pumps in Saccharomyces cerevisiae.

    Science.gov (United States)

    Kodedová, Marie; Sychrová, Hana

    2015-01-01

    We investigated the impact of the deletions of genes from the final steps in the biosynthesis of ergosterol (ERG6, ERG2, ERG3, ERG5, ERG4) on the physiological function of the Saccharomyces cerevisiae plasma membrane by a combination of biological tests and the diS-C3(3) fluorescence assay. Most of the erg mutants were more sensitive than the wild type to salt stress or cationic drugs, their susceptibilities were proportional to the hyperpolarization of their plasma membranes. The different sterol composition of the plasma membrane played an important role in the short-term and long-term processes that accompanied the exposure of erg strains to a hyperosmotic stress (effect on cell size, pH homeostasis and survival of yeasts), as well as in the resistance of cells to antifungal drugs. The pleiotropic drug-sensitive phenotypes of erg strains were, to a large extent, a result of the reduced efficiency of the Pdr5 efflux pump, which was shown to be more sensitive to the sterol content of the plasma membrane than Snq2p. In summary, the erg4Δ and erg6Δ mutants exhibited the most compromised phenotypes. As Erg6p is not involved in the cholesterol biosynthetic pathway, it may become a target for a new generation of antifungal drugs.

  8. Potential of BODIPY-cholesterol for analysis of cholesterol transport and diffusion in living cells

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Lund, Frederik Wendelboe; Röhrl, Clemens

    2016-01-01

    Cholesterol is an abundant and important lipid component of cellular membranes. Analysis of cholesterol transport and diffusion in living cells is hampered by the technical challenge of designing suitable cholesterol probes which can be detected for example by optical microscopy. One strategy...... is to use intrinsically fluorescent sterols, as dehydroergosterol (DHE), having minimal chemical alteration compared to cholesterol but giving low fluorescence signals in the UV region of the spectrum. Alternatively, one can use dye-tagged cholesterol analogs and in particular BODIPY-cholesterol (BChol......), whose synthesis and initial characterization was pioneered by Robert Bittman. Here, we give a general overview of the properties and applications but also limitations of BODIPY-tagged cholesterol probes for analyzing intracellular cholesterol trafficking. We describe our own experiences...

  9. Plant sterols and plant stanols in the management of dyslipidaemia and prevention of cardiovascular disease.

    Science.gov (United States)

    Gylling, Helena; Plat, Jogchum; Turley, Stephen; Ginsberg, Henry N; Ellegård, Lars; Jessup, Wendy; Jones, Peter J; Lütjohann, Dieter; Maerz, Winfried; Masana, Luis; Silbernagel, Günther; Staels, Bart; Borén, Jan; Catapano, Alberico L; De Backer, Guy; Deanfield, John; Descamps, Olivier S; Kovanen, Petri T; Riccardi, Gabriele; Tokgözoglu, Lale; Chapman, M John

    2014-02-01

    This EAS Consensus Panel critically appraised evidence relevant to the benefit to risk relationship of functional foods with added plant sterols and/or plant stanols, as components of a healthy lifestyle, to reduce plasma low-density lipoprotein-cholesterol (LDL-C) levels, and thereby lower cardiovascular risk. Plant sterols/stanols (when taken at 2 g/day) cause significant inhibition of cholesterol absorption and lower LDL-C levels by between 8 and 10%. The relative proportions of cholesterol versus sterol/stanol levels are similar in both plasma and tissue, with levels of sterols/stanols being 500-/10,000-fold lower than those of cholesterol, suggesting they are handled similarly to cholesterol in most cells. Despite possible atherogenicity of marked elevations in circulating levels of plant sterols/stanols, protective effects have been observed in some animal models of atherosclerosis. Higher plasma levels of plant sterols/stanols associated with intakes of 2 g/day in man have not been linked to adverse effects on health in long-term human studies. Importantly, at this dose, plant sterol/stanol-mediated LDL-C lowering is additive to that of statins in dyslipidaemic subjects, equivalent to doubling the dose of statin. The reported 6-9% lowering of plasma triglyceride by 2 g/day in hypertriglyceridaemic patients warrants further evaluation. Based on LDL-C lowering and the absence of adverse signals, this EAS Consensus Panel concludes that functional foods with plant sterols/stanols may be considered 1) in individuals with high cholesterol levels at intermediate or low global cardiovascular risk who do not qualify for pharmacotherapy, 2) as an adjunct to pharmacologic therapy in high and very high risk patients who fail to achieve LDL-C targets on statins or are statin- intolerant, 3) and in adults and children (>6 years) with familial hypercholesterolaemia, in line with current guidance. However, it must be acknowledged that there are no randomised, controlled

  10. Sterol composition of shellfish species commonly consumed in the United States

    Directory of Open Access Journals (Sweden)

    Katherine M. Phillips

    2012-10-01

    Full Text Available Background: Shellfish can be a component of a healthy diet due to a low fat and high protein content, but the cholesterol content of some species is often cited as a reason to limit their consumption. Data on levels of non-cholesterol sterols in commonly consumed species are lacking. Objective: Shellfish were sampled and analyzed to update sterol data in the United States Department of Agriculture (USDA National Nutrient Database for Standard Reference. Design: Using a nationwide sampling plan, raw shrimp and sea scallops, canned clams, and steamed oysters, blue crab, and lobster were sampled from 12 statistically selected supermarkets across the United States in 2007-08. For each species, four composites were analyzed, each comprised of samples from three locations; shrimp and scallops from six single locations were also analyzed separately. Using validated analytical methodology, 14 sterols were determined in total lipid extracts after saponification and derivatization to trimethylsilyethers, using gas chromatography for quantitation and mass spectrometry for confirmation of components. Results: Crab, lobster, and shrimp contained significant cholesterol (96.2–27 mg/100 g; scallops and clams had the lowest concentrations (23.4–30.1 mg/100 g. Variability in cholesterol among single-location samples of shrimp was low. The major sterols in the mollusks were brassicasterol (12.6–45.6 mg/100 g and 24-methylenecholesterol (16.7–41.9 mg/100 g, with the highest concentrations in oysters. Total non-cholesterol sterols were 46.5–75.6 mg/100 g in five single-location scallops samples, but 107 mg/100 g in the sixth, with cholesterol also higher in that sample. Other prominent non-cholesterol sterols in mollusks were 22-dehydrocholesterol, isofucosterol, clionasterol, campesterol, and 24-norcholesta-5,22-diene-3β-ol (4–21 mg/100 g. Conclusions: The presence of a wide range of sterols, including isomeric forms, in shellfish makes the analysis

  11. Effect of plant sterols on the lipid profile of patients with hypercholesterolaemia. Randomised, experimental study

    Directory of Open Access Journals (Sweden)

    Lloret Ángeles

    2011-09-01

    Full Text Available Abstract Background Studies have been conducted on supplementing the daily diet with plant sterol ester-enriched milk derivatives in order to reduce LDL-cholesterol levels and, consequently, cardiovascular risk. However, clinical practice guidelines on hypercholesterolaemia state that there is not sufficient evidence to recommend their use in subjects with hypercholesterolaemia. The main objective of this study is to determine the efficacy of the intake of 2 g of plant sterol esters a day in lowering LDL-cholesterol levels in patients diagnosed with hypercholesterolaemia. The specific objectives are: 1 to quantify the efficacy of the daily intake of plant sterol esters in lowering LDL-cholesterol, total cholesterol and cardiovascular risk in patients with hypercholesterolaemia; 2 to evaluate the occurrence of adverse effects of the daily intake of plant sterol esters; 3 to identify the factors that determine a greater reduction in lipid levels in subjects receiving plant sterol ester supplements. Methods/Design Randomised, double-blind, placebo controlled experimental trial carried out at family doctors' surgeries at three health centres in the Health Area of Albacete (Spain. The study subjects will be adults diagnosed with "limit" or "defined" hypercholesterolaemia and who have LDL cholesterol levels of 130 mg/dl or over. A dairy product in the form of liquid yoghurt containing 2 g of plant sterol ester per container will be administered daily after the main meal, for a period of 24 months. The control group will receive a daily unit of yogurt not supplemented with plant sterol esters that has a similar appearance to the enriched yoghurt. The primary variable is the change in lipid profile at 1, 3, 6, 12, 18 and 24 months. The secondary variables are: change in cardiovascular risk, adherence to the dairy product, adverse effects, adherence to dietary recommendations, frequency of food consumption, basic physical examination data, health

  12. Effect of plant sterols on the lipid profile of patients with hypercholesterolaemia. Randomised, experimental study.

    Science.gov (United States)

    Párraga, Ignacio; López-Torres, Jesús; Andrés, Fernando; Navarro, Beatriz; del Campo, José M; García-Reyes, Mercedes; Galdón, María P; Lloret, Angeles; Precioso, Juan C; Rabanales, Joseba

    2011-09-12

    Studies have been conducted on supplementing the daily diet with plant sterol ester-enriched milk derivatives in order to reduce LDL-cholesterol levels and, consequently, cardiovascular risk. However, clinical practice guidelines on hypercholesterolaemia state that there is not sufficient evidence to recommend their use in subjects with hypercholesterolaemia. The main objective of this study is to determine the efficacy of the intake of 2 g of plant sterol esters a day in lowering LDL-cholesterol levels in patients diagnosed with hypercholesterolaemia. The specific objectives are: 1) to quantify the efficacy of the daily intake of plant sterol esters in lowering LDL-cholesterol, total cholesterol and cardiovascular risk in patients with hypercholesterolaemia; 2) to evaluate the occurrence of adverse effects of the daily intake of plant sterol esters; 3) to identify the factors that determine a greater reduction in lipid levels in subjects receiving plant sterol ester supplements. Randomised, double-blind, placebo controlled experimental trial carried out at family doctors' surgeries at three health centres in the Health Area of Albacete (Spain). The study subjects will be adults diagnosed with "limit" or "defined" hypercholesterolaemia and who have LDL cholesterol levels of 130 mg/dl or over. A dairy product in the form of liquid yoghurt containing 2 g of plant sterol ester per container will be administered daily after the main meal, for a period of 24 months. The control group will receive a daily unit of yogurt not supplemented with plant sterol esters that has a similar appearance to the enriched yoghurt. The primary variable is the change in lipid profile at 1, 3, 6, 12, 18 and 24 months. The secondary variables are: change in cardiovascular risk, adherence to the dairy product, adverse effects, adherence to dietary recommendations, frequency of food consumption, basic physical examination data, health problems, lipid-lowering medication, physical activity

  13. Subinhibitory concentration of octenidine and pirtenidine: influence on the lipid and sterol contents of Candida albicans.

    Science.gov (United States)

    Ghannoum, M A; Moussa, N M; Whittaker, P; Swairjo, I; Abu-Elteen, K H

    1992-01-01

    The effect of subinhibitory concentrations of octenidine and pirtenidine on the lipid and sterol composition of Candida albicans was investigated. The total lipid and sterol contents of C. albicans grown in the presence of either octenidine or pirtenidine were reduced compared with control-grown cells. The major differences in the lipid composition of drug-grown and control cells were phosphatidylglycerol, phosphatidylcholine and monogalactosyldiacylglycerol, which increased in the presence of octenidine and pirtenidine. Lower proportions of phosphatidic acid were found in yeasts grown in the presence of the drugs when compared with control C. albicans. Fatty acid analysis of control-grown cells showed that the major fatty acids were C16 and C18. Drug-grown cells had higher proportions of palmitic and linolenic acids but lower proportion of oleic acid. The C16/C18 ratios were higher for octenidine- and pirtenidine-grown cells than control cells. Differences in the fatty acid composition of major phospholipids and neutral lipids between drug-grown and control yeasts were also observed. Sterol analysis of control-grown cells showed that the major sterol present was ergosterol (65.9%). A significant increase in squalene and 4,14-dimethylzymosterol was observed in pirtenidine-treated cells, while octenidine-treated cells showed an increase in zymosterol and obtusifoliol contents. Our results suggest that octenidine and pirtenidine affect the lipids and sterol of C. albicans in different ways. The implications of these findings on the mode of action of these two drugs is discussed.

  14. Changes in the sterol compositions of milk thistle oil (Silybium marianum L.) during seed maturation

    Energy Technology Data Exchange (ETDEWEB)

    Harrabi, S.; Curtis, S.; Hayet, F.; Mayer, P.M.

    2016-07-01

    In this study, the total lipid content and sterol compositions were determined during the development of milk thistle seeds. The oil content increased to a maximum value of 36±1.7% and then declined to reach a value of 30.5±0.9% at full maturity. The sterol content of milk thistle seeds was affected by the ripening degree of the seeds. At the early stages of seed maturation, Δ7 -stigmastenol was the most abundant sterol followed by β-sitosterol. However, at full maturity, β-sitosterol was the most predominant sterol (46.50±0.8%). As the seed developed, campesterol and stigmasterol amounts increased, while Δ7 -avenasterol content decreased. It can be concluded that milk thistle seed oil has a characteristic sterol pattern comparable to the ones elucidated for olive oil and corn oil. The extracted oil from milk thistle seeds is rich in phytosterols and could be used in foodpreparation and human nutrition. (Author)

  15. Crystal structure of the human sterol transporter ABCG5/ABCG8.

    Science.gov (United States)

    Lee, Jyh-Yeuan; Kinch, Lisa N; Borek, Dominika M; Wang, Jin; Wang, Junmei; Urbatsch, Ina L; Xie, Xiao-Song; Grishin, Nikolai V; Cohen, Jonathan C; Otwinowski, Zbyszek; Hobbs, Helen H; Rosenbaum, Daniel M

    2016-05-26

    ATP binding cassette (ABC) transporters play critical roles in maintaining sterol balance in higher eukaryotes. The ABCG5/ABCG8 heterodimer (G5G8) mediates excretion of neutral sterols in liver and intestines. Mutations disrupting G5G8 cause sitosterolaemia, a disorder characterized by sterol accumulation and premature atherosclerosis. Here we use crystallization in lipid bilayers to determine the X-ray structure of human G5G8 in a nucleotide-free state at 3.9 Å resolution, generating the first atomic model of an ABC sterol transporter. The structure reveals a new transmembrane fold that is present in a large and functionally diverse superfamily of ABC transporters. The transmembrane domains are coupled to the nucleotide-binding sites by networks of interactions that differ between the active and inactive ATPases, reflecting the catalytic asymmetry of the transporter. The G5G8 structure provides a mechanistic framework for understanding sterol transport and the disruptive effects of mutations causing sitosterolaemia.

  16. Assessment of Fecal Contamination in Oklahoma Water Systems through the Use of Sterol Fingerprints

    Directory of Open Access Journals (Sweden)

    Yueming Lu

    2016-11-01

    Full Text Available Fecal contamination is a major concern for water quality management, since the fecal materials are associated with pathogens that can cause illness wherever water is used for recreational, drinking and aquaculture purposes. In order to monitor source(s of fecal contamination in Oklahoma water systems, sterol profiles were previously examined in rural and urban samples collected from the Illinois River Basin and the Norman Wastewater Treatment Plant (WWTP, respectively. Two distinctive, qualitatively and quantitatively, sterol fingerprints were recognized. Despite the effective removal of organic material by the Norman WWTP, human-derived sterol fingerprints, characterized by a predominance of fecal stanols such as coprostanol, were still significant in the output from the plant. The source of fecal material in the Illinois River samples (rural was defined as being characteristic of corn-feed chicken manure originating from surrounding feedlots through the principal component analysis (PCA of the sterol distributions and carbon compound specific isotope analysis of selected sterols (CSIA, δ13C. Thiosteranes, formed during sludge treatments, were also shown to be useful tracers for monitoring sludge application in agriculture fields. The results obtained were used to provide water management authorities with qualitative insights into the source of fecal material inputs into the environment.

  17. Fomentarols A-D, sterols from the polypore macrofungus Fomes fomentarius.

    Science.gov (United States)

    Zang, Yi; Xiong, Juan; Zhai, Wen-Zhu; Cao, Lei; Zhang, Sheng-Ping; Tang, Yu; Wang, Ji; Su, Jing-Jing; Yang, Guo-Xun; Zhao, Yun; Fan, Hui; Xia, Gang; Wang, Chuan-Gui; Hu, Jin-Feng

    2013-08-01

    Four (1-4) hitherto unknown and seven (5-11) known ergostane-type sterols were isolated from the EtOH extract of the dried fruiting bodies of the polypore macrofungus Fomes fomentarius. On the basis of spectroscopic analysis, the structures of polyhydroxylated sterols 1-4 were elucidated to be (22E,24R)-3β,5α,6β,14α-tetrahydroxyergosta-7,9(11),22-triene (fomentarol A, 1), (22E,24R)-3β,5β,6α,7α-tetrahydroxy-8α,9α-dihydroergosta-14,22-diene (fomentarol B, 2), (22E,24R)-3β,5α-dihydroxy-6β-ethoxyergosta-7,22-diene (fomentarol C, 3), and (22E,24S)-3β,25-dihydroxy-15α-O-β-D-glucopyranosylergosta-7,22-dien-6-one (fomentarol D, 4), respectively. Rings A/B and B/C are in turn cis-fused in compound 2, which is uncommon in natural ergostane-type sterols. The potential biogenetic relationship of 2 and other ergostane-type sterols isolated from F. fomentarius was briefly discussed. Moderate cytotoxic effects of the isolated sterols against a small panel of human cancer cell lines were also established. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. A Novel Sterol Desaturase-Like Protein Promoting Dealkylation of Phytosterols in Tetrahymena thermophila▿

    Science.gov (United States)

    Tomazic, Mariela L.; Najle, Sebastián R.; Nusblat, Alejandro D.; Uttaro, Antonio D.; Nudel, Clara B.

    2011-01-01

    The gene TTHERM_00438800 (DES24) from the ciliate Tetrahymena thermophila encodes a protein with three conserved histidine clusters, typical of the fatty acid hydroxylase superfamily. Despite its high similarity to sterol desaturase-like enzymes, the phylogenetic analysis groups Des24p in a separate cluster more related to bacterial than to eukaryotic proteins, suggesting a possible horizontal gene transfer event. A somatic knockout of DES24 revealed that the gene encodes a protein, Des24p, which is involved in the dealkylation of phytosterols. Knocked-out mutants were unable to eliminate the C-24 ethyl group from C29 sterols, whereas the ability to introduce other modifications, such as desaturations at positions C-5(6), C-7(8), and C-22(23), were not altered. Although C-24 dealkylations have been described in other organisms, such as insects, neither the enzymes nor the corresponding genes have been identified to date. Therefore, this is the first identification of a gene involved in sterol dealkylation. Moreover, the knockout mutant and wild-type strain differed significantly in growth and morphology only when cultivated with C29 sterols; under this culture condition, a change from the typical pear-like shape to a round shape and an alteration in the regulation of tetrahymanol biosynthesis were observed. Sterol analysis upon culture with various substrates and inhibitors indicate that the removal of the C-24 ethyl group in Tetrahymena may proceed by a mechanism different from the one currently known. PMID:21257793

  19. Comparison and analysis of fatty acids, sterols, and tocopherols in eight vegetable oils.

    Science.gov (United States)

    Li, Changmo; Yao, Yunping; Zhao, Guozhong; Cheng, Wen; Liu, Huilin; Liu, Chunyang; Shi, Zhen; Chen, Yao; Wang, Shuo

    2011-12-14

    The similarities and differences of eight vegetable oils produced in China were investigated in terms of their fatty acid, sterol, and tocopherol compositions and subsequent data processing by hierarchical clustering analysis and principal component analysis. The lipid profiles, acquired by analytical techniques tailored to each lipid class, revealed great similarities among the fatty acid profiles of corn and sesame oil as well as few differences in their sterol profiles. It turns out that not only was there great similarity between the fatty acid profiles of corn oil and sesame oil but also there were not too many differences for the sterol profiles. Sunflower and tea-seed oil showed similar sterol compositions, while the tea-seed oil tocopherol was very similar to palm oil. The results demonstrated that the use of only one of these profiles was unreliable for indentifying oil origin and authenticity. In contrast, the use of the sterol or tocopherol profile together with the fatty acid profile more accurately discriminates these oils.

  20. Effect of plant sterols and tannins on Phytophthora ramorum growth and sporulation.

    Science.gov (United States)

    Stong, Rachel A; Kolodny, Eli; Kelsey, Rick G; González-Hernández, M P; Vivanco, Jorge M; Manter, Daniel K

    2013-06-01

    Elicitin-mediated acquisition of plant sterols is required for growth and sporulation of Phytophthora spp. This study examined the interactions between elicitins, sterols, and tannins. Ground leaf tissue, sterols, and tannin-enriched extracts were obtained from three different plant species (California bay laurel, California black oak, and Oregon white oak) in order to evaluate the effect of differing sterol/tannin contents on Phytophthora ramorum growth. For all three species, high levels of foliage inhibited P. ramorum growth and sporulation, with a steeper concentration dependence for the two oak samples. Phytophthora ramorum growth and sporulation were inhibited by either phytosterols or tannin-enriched extracts. High levels of sterols diminished elicitin gene expression in P. ramorum; whereas the tannin-enriched extract decreased the amount of 'functional' or ELISA-detectable elicitin, but not gene expression. Across all treatment combinations, P. ramorum growth and sporulation correlated strongly with the amount of ELISA-detectable elicitin (R (2) = 0.791 and 0.961, respectively).

  1. Towards New Insights in the Sterol/Amphotericin Nanochannels Formation: A Molecular Dynamic Simulation Study.

    Science.gov (United States)

    Boukari, Khaoula; Balme, Sébastien; Janot, Jean-Marc; Picaud, Fabien

    2016-06-01

    Amphotericin B (AmB) is a well-known polyene which self-organizes into membrane cell in order to cause the cell death. Its specific action towards fungal cell is not fully understood but was proved to become from sterol composition. The mechanism was shown experimentally to require the formation of stable sterol/polyene couples which could then organize in a nanochannel. This would allow the leakage of ions responsible for the death of fungal cells, only. In this present study, we investigate the arrangement of AmB/sterols in biological membrane using molecular dynamic simulations in order to understand the role of the sterol structure on the antifungal action of the polyene. We show in particular that the nanochannels tend to close up when cell was composed with cholesterol (animal cell) due to strong interaction between amphotericin and sterol. On the other side, with ergosterol (fungal cell) the largest interactions between amphotericin and lipid membrane lead to the appearance of large hole that could favor the important leakage of ions and thus, the fungal cell death. This work appears as a good complement in the extensive studies linked to the understanding of the antifungal molecules in membrane cells.

  2. Analysis of vascular development in the hydra sterol biosynthetic mutants of Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Margaret Pullen

    Full Text Available The control of vascular tissue development in plants is influenced by diverse hormonal signals, but their interactions during this process are not well understood. Wild-type sterol profiles are essential for growth, tissue patterning and signalling processes in plant development, and are required for regulated vascular patterning.Here we investigate the roles of sterols in vascular tissue development, through an analysis of the Arabidopsis mutants hydra1 and fackel/hydra2, which are defective in the enzymes sterol isomerase and sterol C-14 reductase respectively. We show that defective vascular patterning in the shoot is associated with ectopic cell divisions. Expression of the auxin-regulated AtHB8 homeobox gene is disrupted in mutant embryos and seedlings, associated with variably incomplete vascular strand formation and duplication of the longitudinal axis. Misexpression of the auxin reporter proIAA2ratioGUS and mislocalization of PIN proteins occurs in the mutants. Introduction of the ethylene-insensitive ein2 mutation partially rescues defective cell division, localization of PIN proteins, and vascular strand development.The results support a model in which sterols are required for correct auxin and ethylene crosstalk to regulate PIN localization, auxin distribution and AtHB8 expression, necessary for correct vascular development.

  3. Microbial symbionts shape the sterol profile of the xylem-feeding woodwasp, Sirex noctilio.

    Science.gov (United States)

    Thompson, Brian M; Grebenok, Robert J; Behmer, Spencer T; Gruner, Daniel S

    2013-01-01

    The symbiotic fungus Amylostereum areolatum is essential for growth and development of larvae of the invasive woodwasp, Sirex noctilio. In the nutrient poor xylem of pine trees, upon which Sirex feeds, it is unknown whether Amylostereum facilitates survival directly through consumption (mycetophagy) and/or indirectly through digestion of recalcitrant plant polymers (external rumen hypothesis). We tested these alternative hypotheses for Amylostereum involvement in Sirex foraging using the innate dependency of all insects on dietary sources of sterol and the unique sterols indicative of fungi and plants. We tested alternative hypotheses by using GC-MS to quantify concentrations of free and bound sterol pools from multiple life-stages of Sirex, food sources, and waste products in red pine (Pinus resinosa). Cholesterol was the primary sterol found in all life-stages of Sirex. However, cholesterol was not found in significant quantities in either plant or fungal resources. Ergosterol was the most prevalent sterol in Amylostereum but was not detectable in either wood or insect tissue (importance for fungal enzymes, including the external digestion of recalcitrant plant polymers (e.g., lignin and cellulose), shaping this insect-fungal symbiosis.

  4. Regulation of squalene synthase, a key enzyme of sterol biosynthesis, in tobacco.

    Science.gov (United States)

    Devarenne, Timothy P; Ghosh, Anirban; Chappell, Joe

    2002-07-01

    Squalene synthase (SS) represents a putative branch point in the isoprenoid biosynthetic pathway capable of diverting carbon flow specifically to the biosynthesis of sterols and, hence, is considered a potential regulatory point for sterol metabolism. For example, when plant cells grown in suspension culture are challenged with fungal elicitors, suppression of sterol biosynthesis has been correlated with a reduction in SS enzyme activity. The current study sought to correlate changes in SS enzyme activity with changes in the level of the corresponding protein and mRNA. Using an SS-specific antibody, the initial suppression of SS enzyme activity in elicitor-challenged cells was not reflected by changes in the absolute level of the corresponding polypeptide, implicating a post-translational control mechanism for this enzyme activity. In comparison, the absolute level of the SS mRNA did decrease approximately 5-fold in the elicitor-treated cells, which is suggestive of decreased transcription of the SS gene. Study of SS in intact plants was also initiated by measuring the level of SS enzyme activity, the level of the corresponding protein, and the expression of SS gene promoter-reporter gene constructs in transgenic plants. SS enzyme activity, polypeptide level, and gene expression were all localized predominately to the shoot apical meristem, with much lower levels observed in leaves and roots. These later results suggest that sterol biosynthesis is localized to the apical meristems and that apical meristems may be a source of sterols for other plant tissues.

  5. Traditional herbal medicines: potential degradation of sterols and sterolins by microbial contaminants

    Directory of Open Access Journals (Sweden)

    S. Govender

    2010-01-01

    Full Text Available Medicinal plants with a high content of sterols and sterolins, such as Bulbine natalensis (rooiwortel and Hypoxis hemerocallidea (African potato, are commonly and inappropriately used in South Africa for the treatment of HIV/AIDS due to the inaccessibility of antiretroviral drugs. This study investigated the presence of active compounds, such as sterols and sterolins, in the herbal medicines. The research was carried out in the Nelson Mandela Metropole area. The effect of microbial contaminants isolated from the medicines on sterols and sterolins of rooiwortel extracts was assessed. Sterols and sterolins were detected in rooiwortel, raw African potatoes and one ready-made mixture. Co-incubation of rooiwortel with bacteria (Bacillus spp. and Pseudomonas putida and fungi (Aspergillus spp., Penicillium spp. and Mucor spp. that were isolated from these samples increased the rate of degradation of sterols and sterolins over time, with slower degradation at 4°C than at 28°C.

  6. Biological investigations of Indian phaeophyceae: 17. Seasonal variation of antibacterial activity of total sterols obtained from frozen samples of Sargassum johnstonii Setchell et Gardner

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.P.S.

    From lipid fraction of frozen samples of Sargassum johnstonii unsaponifiable part was extracted with diethyl ether to isolate total sterols. The extracted sterols were obtained for a period of nine months and tested against test bacteria...

  7. Plant Sterols as Anticancer Nutrients: Evidence for Their Role in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Bruce J. Grattan

    2013-01-01

    Full Text Available While many factors are involved in the etiology of cancer, it has been clearly established that diet significantly impacts one’s risk for this disease. More recently, specific food components have been identified which are uniquely beneficial in mitigating the risk of specific cancer subtypes. Plant sterols are well known for their effects on blood cholesterol levels, however research into their potential role in mitigating cancer risk remains in its infancy. As outlined in this review, the cholesterol modulating actions of plant sterols may overlap with their anti-cancer actions. Breast cancer is the most common malignancy affecting women and there remains a need for effective adjuvant therapies for this disease, for which plant sterols may play a distinctive role.

  8. New marine sterols from an algal-bearing gorgonian coral Pinnigorgia sp.

    Science.gov (United States)

    Chang, Yu-Chia; Chen, Nan-Fu; Hwang, Tsong-Long; Tseng, Chung-Chih; Wu, Tung-Ying; Peng, Bo-Rong; Wen, Zhi-Hong; Fang, Lee-Shing; Wu, Yang-Chang; Sheu, Jyh-Horng; Sung, Ping-Jyun

    2016-11-01

    Four new marine sterols, (22E,24R)-ergosta-5,22-diene-3β,11α-diol (1), (24S)-ergosta-5-ene-3β,11α-diol (2), 5α,6α-epoxy-23-demethylgorgost-8-ene-3β,7α-diol (3), and 5α,6α-epoxy-23-demethylgorgost-8(14)-ene-3β,7α-diol (4), along with a known metabolite, 23-demethylgorgost-7-ene-3β,5α,6β-triol (5), were isolated from an algal-bearing gorgonian coral Pinnigorgia sp., collected off the waters of Taiwan. The structures of these sterols were elucidated on the basis of spectroscopic methods. Sterols 1-5 were tested for in vitro cytotoxicity in hepatic stellate cells (HSCs). Proliferation of HSCs plays a key role in the pathogenesis of liver fibrosis. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Sewage contamination of sediments from two Portuguese Atlantic coastal systems, revealed by fecal sterols.

    Science.gov (United States)

    Rada, Jesica P A; Duarte, Armando C; Pato, Pedro; Cachada, Anabela; Carreira, Renato S

    2016-02-15

    Fecal sterols in sediments were used to assess the degree of sewage contamination in Ria de Aveiro lagoon and Mondego River estuary for the first time. Coprostanol, the major fecal sterol, averaged 1.82 ± 4.12 μg g(-1), with maxima of 16.6 μg g(-1). The northwestern sector of the Ria and a marina at Mondego estuary showed the highest level of sewage contamination. This scenario was confirmed by several diagnostic ratios based on fecal sterols and other phytosterols. Our data revealed that in spite of the improvements achieved in the last decades, there is still a need for control the organic inputs into the aquatic environment in the studied regions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Action of lovastatin, simvastatin, and pravastatin on sterol synthesis and their antiproliferative effect in cultured myoblasts from human striated muscle

    NARCIS (Netherlands)

    Vliet, A.K. van; Nègre-Arrariou, P.; Thiel, G.C.F. van; Bolhuis, P.A.; Cohen, L.H.

    1996-01-01

    Lovastatin, simvastatin, and pravastatin are fairly strong inhibitors of sterol synthesis in human myoblasts in culture. Lovastatin and simvastatin have IC50 values of 19 ± 6 nM and 4.0 ± 2.3 nM, respectively. Pravastatin is a weaker inhibitor of sterol synthesis (IC50 value of 110 ± 38 nM). Through

  11. Triglycerides, fatty acids, sterols, mono- and disaccharides and sugar alcohols in human milk and current types of infant formula milk

    NARCIS (Netherlands)

    Huisman, M; vanBeusekom, CM; Nijeboer, HJ; Muskiet, FAJ; Boersma, ER

    Objective: To investigate differences in the fatty acid composition, sterols, minor carbohydrates and sugar alcohols between human and formula milk. Design: We analyzed the concentrations of triglycerides, sterols, di- and monosaccharides and sugar alcohols, as well as the fatty acid composition of

  12. Concentrations of surfactants and sterols in the surface microlayer of the estuarine areas of Selangor River, Malaysia

    Science.gov (United States)

    Alsalahi, Murad Ali; Talib Latif, Mohd; Mohd Ali, Masni; Dominick, Doreena; Firoz Khan, Md; Bahiyah Abd Wahid, Nurul; Ili Hamizah Mustaffa, Nur

    2016-04-01

    This study determined the concentration of surfactant and sterols as biomarkers in the surface microlayer (SML) in estuarine areas of the Selangor River, Malaysia. SML samples were collected during different seasons using a rotation drum method. The compositions of surfactants in SML were determined as methylene blue active substances (MBAS) and disulphine blue active substances (DBAS) as anionic and cationic surfactants respectively. The concentration of sterols was determined using a gas chromatography equipped with a flame ionisation detector (GC-FID). The results show that the concentrations of surfactants around the estuarine area were dominated by anionic surfactants (MBAS) with average concentrations of 0.39 μmol L-1. The concentrations of total sterols in the SML ranged from 107.06 to 505.55 ng L-1. The surfactants and total sterol concentrations were found to be higher in the wet season. Cholesterol was found to be the most abundant sterols component in the SML of the Selangor River. The diagnostic ratios of sterols show the influence of natural sources and waste on the contribution of sterols in the SML. Further analysis, using principal component analysis (PCA), showed distinct inputs of sterols derived from human activity (40.58%), terrigenous and plant inputs (22.59%) as well as phytoplankton and marine inputs (17.35%).

  13. Potential of the desert locust schistocerca gregaria (Orthoptera: Acrididae) as an unconventional source of dietary and therapeutic sterols

    Science.gov (United States)

    Insects are increasingly being recognized not only as a source of food to feed the ever growing world population but also as potential sources of new products and therapeutic agents, among which are sterols. In this study, we sought to profile sterols and their derivatives present in the desert locu...

  14. Triglycerides, fatty acids, sterols, mono- and disaccharides and sugar alcohols in human milk and current types of infant formula milk

    NARCIS (Netherlands)

    Huisman, M; vanBeusekom, CM; Nijeboer, HJ; Muskiet, FAJ; Boersma, ER

    1996-01-01

    Objective: To investigate differences in the fatty acid composition, sterols, minor carbohydrates and sugar alcohols between human and formula milk. Design: We analyzed the concentrations of triglycerides, sterols, di- and monosaccharides and sugar alcohols, as well as the fatty acid composition of

  15. A LONG CHAIN ALCOHOL AND TWO STEROL COMPOUNDS FROM THE HEXANE EXTRACT OF STEM BARK OF Aglaia odorata Lour. (Meliaceae

    Directory of Open Access Journals (Sweden)

    Tukiran Tukiran

    2010-06-01

    Full Text Available A long chain alcohol, 1-eicosanol together with two sterols, β-sitosterol and stigmasterol had been isolated from hexane extract of stem bark of pacar cina (Aglaia odorata Lour (Meliaceae. These structures had been established based on spectroscopic data (IR and NMR and by comparison to those of standard compounds.   Keywords: Aglaia odorata Lour, Alcohol, Meliaceae, Sterol

  16. Plant oxidosqualene metabolism: cycloartenol synthase-dependent sterol biosynthesis in Nicotiana benthamiana.

    Science.gov (United States)

    Gas-Pascual, Elisabet; Berna, Anne; Bach, Thomas J; Schaller, Hubert

    2014-01-01

    The plant sterol pathway exhibits a major biosynthetic difference as compared with that of metazoans. The committed sterol precursor is the pentacyclic cycloartenol (9β,19-cyclolanost-24-en-3β-ol) and not lanosterol (lanosta-8,24-dien-3β-ol), as it was shown in the late sixties. However, plant genome mining over the last years revealed the general presence of lanosterol synthases encoding sequences (LAS1) in the oxidosqualene cyclase repertoire, in addition to cycloartenol synthases (CAS1) and to non-steroidal triterpene synthases that contribute to the metabolic diversity of C30H50O compounds on earth. Furthermore, plant LAS1 proteins have been unambiguously identified by peptidic signatures and by their capacity to complement the yeast lanosterol synthase deficiency. A dual pathway for the synthesis of sterols through lanosterol and cycloartenol was reported in the model Arabidopsis thaliana, though the contribution of a lanosterol pathway to the production of 24-alkyl-Δ(5)-sterols was quite marginal (Ohyama et al. (2009) PNAS 106, 725). To investigate further the physiological relevance of CAS1 and LAS1 genes in plants, we have silenced their expression in Nicotiana benthamiana. We used virus induced gene silencing (VIGS) based on gene specific sequences from a Nicotiana tabacum CAS1 or derived from the solgenomics initiative (http://solgenomics.net/) to challenge the respective roles of CAS1 and LAS1. In this report, we show a CAS1-specific functional sterol pathway in engineered yeast, and a strict dependence on CAS1 of tobacco sterol biosynthesis.

  17. Plant Oxidosqualene Metabolism: Cycloartenol Synthase–Dependent Sterol Biosynthesis in Nicotiana benthamiana

    Science.gov (United States)

    Gas-Pascual, Elisabet; Berna, Anne; Bach, Thomas J.; Schaller, Hubert

    2014-01-01

    The plant sterol pathway exhibits a major biosynthetic difference as compared with that of metazoans. The committed sterol precursor is the pentacyclic cycloartenol (9β,19-cyclolanost-24-en-3β-ol) and not lanosterol (lanosta-8,24-dien-3β-ol), as it was shown in the late sixties. However, plant genome mining over the last years revealed the general presence of lanosterol synthases encoding sequences (LAS1) in the oxidosqualene cyclase repertoire, in addition to cycloartenol synthases (CAS1) and to non-steroidal triterpene synthases that contribute to the metabolic diversity of C30H50O compounds on earth. Furthermore, plant LAS1 proteins have been unambiguously identified by peptidic signatures and by their capacity to complement the yeast lanosterol synthase deficiency. A dual pathway for the synthesis of sterols through lanosterol and cycloartenol was reported in the model Arabidopsis thaliana, though the contribution of a lanosterol pathway to the production of 24-alkyl-Δ5-sterols was quite marginal (Ohyama et al. (2009) PNAS 106, 725). To investigate further the physiological relevance of CAS1 and LAS1 genes in plants, we have silenced their expression in Nicotiana benthamiana. We used virus induced gene silencing (VIGS) based on gene specific sequences from a Nicotiana tabacum CAS1 or derived from the solgenomics initiative (http://solgenomics.net/) to challenge the respective roles of CAS1 and LAS1. In this report, we show a CAS1-specific functional sterol pathway in engineered yeast, and a strict dependence on CAS1 of tobacco sterol biosynthesis. PMID:25343375

  18. Plasma plant sterols serve as poor markers of cholesterol absorption in man[S

    Science.gov (United States)

    Jakulj, Lily; Mohammed, Hussein; van Dijk, Theo H.; Boer, Theo; Turner, Scott; Groen, Albert K.; Vissers, Maud N.; Stroes, Erik S. G.

    2013-01-01

    The validation of the use of plasma plant sterols as a marker of cholesterol absorption is frail. Nevertheless, plant sterol concentrations are routinely used to describe treatment-induced changes in cholesterol absorption. Their use has also been advocated as a clinical tool to tailor cholesterol-lowering therapy. Prior to wider implementation, however, the validity of plant sterols as absorption markers needs solid evaluation. Therefore, we compared plasma plant sterol concentrations to gold-standard stable isotope-determined cholesterol absorption. Plasma campesterol/TC concentrations (camp/TC) were measured in a population of 175 mildly hypercholesterolemic individuals (age: 59.7 ± 5.6 years; BMI: 25.5 ± 2.9kg/m2; LDL-C: 4.01 ± 0.56 mmol/l). We compared cholesterol absorption according to the plasma dual-isotope method in subjects with the highest camp/TC concentrations (N = 41, camp/TC: 2.14 ± 0.68 μg/mg) and the lowest camp/TC concentrations (N = 39, camp/TC: 0.97 ± 0.22 μg/mg). Fractional cholesterol absorption did not differ between the groups (24 ± 12% versus 25 ± 16%, P = 0.60), nor was it associated with plasma camp/TC concentrations in the total population of 80 individuals (β = 0.13; P = 0.30, adjusted for BMI and plasma triglycerides). Our findings do not support a relation between plasma plant sterol concentrations and true cholesterol absorption and, therefore, do not favor the use of these sterols as markers of cholesterol absorption. This bears direct consequences for the interpretation of earlier studies, as well as for future studies targeting intestinal regulation of cholesterol metabolism. PMID:23178226

  19. Recent advances in plant sterol%植物甾醇的研究进展

    Institute of Scientific and Technical Information of China (English)

    张斌; 郁听; 栗磊; 孟祥河

    2015-01-01

    研究发现,植物甾醇能同时降低血清中总胆固醇含量和低密度脂蛋白胆固醇水平,并在2010年被我国批准为新资源食品.文中简要介绍了植物甾醇的性质、来源及生理功能,总结了典型的植物甾醇分离提取工艺,并综述了植物甾醇的改性研究和甾醇氧化产物研究进展,重点阐述了天然植物甾醇及其氧化物的安全性问题,为甾醇的工业应用提供一定的借鉴作用.%Researches have found out that plant sterol could reduce total cholesterol and lower the density lipoprotein cholesterol in serum.And it had been approved as a new resource food by our country in 2010.This paper briefly introduced the properties,sources and physiological functions of plant sterol.At the same time,we summarized the processes of separation and extraction of typical plant sterol,as well as the modification research and progress of research of plant sterol oxidation products.We put emphasis on the safety of natural plant sterol and its oxidation products,which could provide a certain reference for industrial application of plant sterol.

  20. Tracing the Temporal and Spatial Variations in the Origin of Fecal Material in Three Oklahoma Watersheds Using Sterol Fingerprints

    Science.gov (United States)

    Lu, Y.; Philp, P. R.

    2014-12-01

    Organic wastes, in particular fecal material, are qualified as one of the major causes of water quality deterioration. Their accumulation in water bodies may increase algal proliferation and eutrophication and the number of pathogenic organisms, which are responsible for many intestinal diseases especially when the water is used for recreational activities and/or as a supply for drinking water. In order to estimate the risk level associated with primary body contact in recreational water bodies, enumeration of some specific micro-organisms, such as Enterococci and Escherichia coli, are commonly used. Sterol distributions can provide some relevant information on the origin of fecal material in water system, since they are ubiquitous organic compounds and their distributions in many warm-blooded animal feces can be used as evidence for their source. In this study, we monitored fecal material contamination in three Oklahoma watersheds based on sterol fingerprints over a one-year period (2012 ~ 2013). The sterols from sediments and water samples (sterols associated to suspended particles as well as free sterols in water) were recovered using sonication and solid phase extraction (SPE), respectively, using different organic solvents. They were then identified and quantified by gas chromatography - mass spectrometry (GC-MS) using an internal standard. The GC-MS was previously calibrated with a sterol mixture injected at different concentrations. Our primary results show that the concentration of total sterols generally increases from the Upper Canadian sterols commonly represent a small proportion (sterols quantified in these three basins. Their distributions show a significant contribution from herbivore feces. By means of this monitoring, we are able to determine the presence of fecal contamination and provide a better understanding on the ability of using sterol fingerprints to determine the origin of the fecal contamination. Additionally, such a sampling strategy

  1. Fluorescent microspheres

    Science.gov (United States)

    Rembaum, A.

    1978-01-01

    Latex particles with attached antibodies have potential biochemical and environmental applications. Human red blood cells and lymphocytes have been labeled with fluorescent microspheres by either direct or indirect immunological technique. Immunolatex spheres can also be used for detecting and localizing specific cell surface receptors. Hormones and toxins may also be bondable.

  2. The biological activity of a-mangostin, a larvicidal botanic mosquito sterol carrier protein-2 inhibitor

    Science.gov (United States)

    Alpha-mangostin derived from mangosteen was identified as a mosquito sterol carrier protein-2 inhibitor via high throughput insecticide screening. Alpha-mangostin was tested for its larvicidal activity against 3rd instar larvae of six mosquito species and the LC50 values range from 0.84 to 2.90 ppm....

  3. Multidrug Transporters and Alterations in Sterol Biosynthesis Contribute to Azole Antifungal Resistance in Candida parapsilosis.

    Science.gov (United States)

    Berkow, Elizabeth L; Manigaba, Kayihura; Parker, Josie E; Barker, Katherine S; Kelly, Stephen L; Rogers, P David

    2015-10-01

    While much is known concerning azole resistance in Candida albicans, considerably less is understood about Candida parapsilosis, an emerging species of Candida with clinical relevance. We conducted a comprehensive analysis of azole resistance in a collection of resistant C. parapsilosis clinical isolates in order to determine which genes might play a role in this process within this species. We examined the relative expression of the putative drug transporter genes CDR1 and MDR1 and that of ERG11. In isolates overexpressing these genes, we sequenced the genes encoding their presumed transcriptional regulators, TAC1, MRR1, and UPC2, respectively. We also sequenced the sterol biosynthesis genes ERG3 and ERG11 in these isolates to find mutations that might contribute to this phenotype in this Candida species. Our findings demonstrate that the putative drug transporters Cdr1 and Mdr1 contribute directly to azole resistance and suggest that their overexpression is due to activating mutations in the genes encoding their transcriptional regulators. We also observed that the Y132F substitution in ERG11 is the only substitution occurring exclusively among azole-resistant isolates, and we correlated this with specific changes in sterol biosynthesis. Finally, sterol analysis of these isolates suggests that other changes in sterol biosynthesis may contribute to azole resistance in C. parapsilosis.

  4. Protective effects of Aloe sterols against UVB-induced photoaging in hairless mice.

    Science.gov (United States)

    Misawa, Eriko; Tanaka, Miyuki; Saito, Marie; Nabeshima, Kazumi; Yao, Ruiqing; Yamauchi, Kouji; Abe, Fumiaki; Yamamoto, Yuki; Furukawa, Fukumi

    2017-03-01

    Aloe vera is a traditional medical plant whose gel has been widely used in skin care. Previously, we have identified Aloe sterols from Aloe vera as active ingredients. This study investigated the protective effects of Aloe sterols without polysaccharides, against ultraviolet B (UVB)-induced skin photoaging in mice using Aloe vera gel extract (AVGE) obtained by supercritical fluid extraction. Aloe vera gel extract was supplemented in the diet (12 or 120 ppm), and HR-1 hairless mice were exposed to UVB irradiation for 7 weeks. Skin measurements and histological and analytical studies were performed. Repeated UVB irradiation induced rough wrinkling of skin with water content reduction and hyperkeratosis. AVGE administration resulted in the significant improvement of UVB-induced skin dryness, epidermal thickness, and wrinkle formation. The AVGE group also suppressed the degenerations of dermal collagen fibers and the appearance of cutaneous apoptosis cells induced by UVB. Furthermore, AVGE administration reduced the excess elevation of pro-inflammatory cytokines (IL-1β and TNF-α) and matrix metalloproteinases (MMP-2, MMP-9, MMP-12, and MMP-13) in UVB-exposed skin. The dietary ingestion of Aloe sterols protected against chronic UVB damage in mouse skin, and our results suggest that Aloe sterols may prevent skin photoaging through the anti-inflammation and MMP regulation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Hydroxylated sterols : matabolism and effects on steroid production and steroid uptake

    NARCIS (Netherlands)

    J.G.M. Huijmans (Jan)

    1989-01-01

    textabstractThe isolated rat adrenal cell was used as a model system. The isolation technique for rat adrenal cells has been extensively studied : in our laboratory (Falke et al., 1975a,b, 1976a,b) . Starting with these cells we looked at the properties of hydroxylated sterols as a precursor for ste

  6. Segregation of sphingolipids and sterols during formation of secretory vesicles at the trans-Golgi network

    DEFF Research Database (Denmark)

    Klemm, Robin W; Ejsing, Christer S.; Surma, Michal A

    2009-01-01

    The trans-Golgi network (TGN) is the major sorting station in the secretory pathway of all eukaryotic cells. How the TGN sorts proteins and lipids to generate the enrichment of sphingolipids and sterols at the plasma membrane is poorly understood. To address this fundamental question in membrane...

  7. Parameters for Martini sterols and hopanoids based on a virtual-site description

    NARCIS (Netherlands)

    Melo, M. N.; Ingolfsson, H. I.; Marrink, S. J.

    2015-01-01

    Sterols play an essential role in modulating bilayer structure and dynamics. Coarse-grained molecular dynamics parameters for cholesterol and related molecules are available for the Martini force field and have been successfully used in multiple lipid bilayer studies. In this work, we focus on the u

  8. Sterols from Thai Marine Sponge Petrosia (Strongylophora) sp. and Their Cytotoxicity.

    Science.gov (United States)

    Pailee, Phanruethai; Mahidol, Chulabhorn; Ruchirawat, Somsak; Prachyawarakorn, Vilailak

    2017-02-23

    Eight new sterols (1-5 and 11-13), together with eight known compounds (6-10 and 14-16) were isolated from marine sponge Petrosia sp. The structures of these compounds were elucidated on the basis of extensive spectroscopic analysis. The cytotoxicity of some compounds against a panel of human cancer cell lines is also reported.

  9. Amino acids, fatty acids and sterols profile of some marine organisms from Portuguese waters.

    Science.gov (United States)

    Pereira, David M; Valentão, Patrícia; Teixeira, Natércia; Andrade, Paula B

    2013-12-01

    Marine organisms have been increasingly regarded as good sources of new drugs for human therapeutics and also as nutrients for human diet. The amino acids, fatty acids and sterols profiles of the widely consumed echinoderms Paracentrotus lividus Lamarck (sea urchin), Holothuria forskali Chiaje (sea cucumber), the gastropod molluscs Aplysia fasciata Poiret and Aplysia punctata Cuvier (sea hares), from Portuguese waters, were established by GC-MS analysis. Overall, 10 amino acids, 14 fatty acids and 4 sterols were determined. In general, all species presented the 10 amino acids identified, with the exceptions of H. forskali, in which no glycine, proline, trans-4-hydroxy-proline or phenylalanine were found, and of A. fasciata which did not contain proline. Unsaturated fatty acids were predominant compounds, with those from the ω-6 series, being in higher amounts than their ω-3 homologues, and cholesterol being the main sterol. The amino acids, fatty acids and sterols qualitative and quantitative composition of A. fasciata, A. punctata and H. forskali is reported here for the first time. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. [Sorption isotherms and sorption thermodynamics of faecal sterols on offshore sediment].

    Science.gov (United States)

    Zhang, Xiao-Lei; Xue, Wen-Ping; Xu, Heng-Zhen; Ma, Xin-Dong

    2012-10-01

    Experiments of faecal sterols adsorption from aqueous solutions onto Dalian offshore sediment were done by a batch equilibrium method,and the sorption of 12 kinds of faecal sterols in sediment were investigated in this paper. It was shown that the adsorption equilibrium time was 24 h, and after 24 h the variation tendency of 5 kinds of fingerprint values was stable. It indicated that adsorption isothermal data was interpreted by the Henry, Freundlich, Langmuir, Duhinin-Radushkevich(D-R) and Temkin equations, and demonstrated that the other 4 isotherms provided stronger data fitting than the Langumir isotherm. It inferred that from D-R model the mean free energy of adsorption process of 12 kinds of faecal sterols was from 7 071.1 J x mol(-1) to 9 128.7 J x mol(-1), and concluded that it was mainly physical adsorption of the sorptive process of 12 kinds of faecal sterols in sediment. It discovered that from the Temkin model the value of K(f) of cholestanone was the maximum, and extrapolated that cholestanone was adsorbed most easily on sediment. It stated that the enthalpy and entropy change of the adsorption were both less than zero, and inferred that the adsorption process was exothermic and spontaneous.

  11. Effects of plant sterols and olive oil phenols on serum lipoproteins in humans

    NARCIS (Netherlands)

    Vissers, M.N.

    2001-01-01

    The studies described in this thesis investigated whether minor components from vegetable oils can improve health by decreasing cholesterol concentrations or oxidative modification of low-density-lipoprotein (LDL) particles.

    The plant sterolsβ-sitosterol and sitostanol are

  12. Plant sterols for adults with hypercholesterolemia treated with or without medication (statins

    Directory of Open Access Journals (Sweden)

    Raquel Bernácer

    2015-07-01

    Full Text Available Hypercholesterolemia is the most common coronary risk factor among the Spanish population; 37.4% of the Spanish adult population have cholesterol levels between 190 and 240 mg/dl. Foods enriched with plant sterols (PS can effectively reduce plasma cholesterol in patients with high levels. However, its effectiveness and safety in adults with moderate hypercholesterolemia who are on medication (statins or not has been less studied. The aim of this review is to establish the possible role of plant sterols in the control of hypercholesterolemia, as well as how safe they are for people with moderate hypercholesterolemia treated with statins. The main studies were looked at, regardless of design, language or publication date which studied the connection between “plant sterols” and “hypercholesterolemia”, using Pubmed/Medline, SCOPUS and Google Scholar databases. The studies brought together in this review show that an intake of between 2 and 3g/day of plant sterols effectively reduces plasma cholesterol levels in patients with hypercholesterolemia. Both clinical studies and available meta-analyses do not indicate any problems related to the drug-nutrient interaction associated with the use of plant sterol-enriched foods. In patients with moderate hypercholesterolemia where the use of statins is not justified a healthy diet, exercise and foods high in PS can provide the best therapeutic approach.

  13. Role of STARD4 and NPC1 in intracellular sterol transport.

    Science.gov (United States)

    Maxfield, Frederick R; Iaea, David B; Pipalia, Nina H

    2016-12-01

    Cholesterol plays an important role in determining the biophysical properties of membranes in mammalian cells, and the concentration of cholesterol in membranes is tightly regulated. Cholesterol moves among membrane organelles by a combination of vesicular and nonvesicular transport pathways, but the details of these transport pathways are not well understood. In this review, we discuss the mechanisms for nonvesicular sterol transport with an emphasis on the role of STARD4, a small, soluble, cytoplasmic sterol transport protein. STARD4 can rapidly equilibrate sterol between membranes, especially membranes with anionic lipid headgroups. We also discuss the sterol transport in late endosomes and lysosomes, which is mediated by a soluble protein, NPC2, and a membrane protein, NPC1. Homozygous mutations in these proteins lead to a lysosomal lipid storage disorder, Niemann-Pick disease type C. Many of the disease-causing mutations in NPC1 are associated with degradation of the mutant NPC1 proteins in the endoplasmic reticulum. Several histone deacetylase inhibitors have been found to rescue the premature degradation of the mutant NPC1 proteins, and one of these is now in a small clinical trial.

  14. Sedimentary 4-desmethyl sterols and n-alkanols in an eutrophic urban estuary, Capibaribe River, Brazil.

    Science.gov (United States)

    Fernandes, M B; Sicre, M A; Cardoso, J N; Macêdo, S J

    1999-06-15

    Sterols, n-alkanols, organic carbon (OC), C/N ratios and carbon isotope data (delta 13C) were investigated in sediments of the urban Capibaribe River estuary, NE Brazil, in order to assess allochthonous and autochthonous sources of organic matter (OM). Sedimentary OC values are high, but C/N ratios and delta 13C data generally fall within the range of values reported in other riverine systems, and suggest mixed inputs from aquatic and terrestrial matter. Mean values for total 4-desmethyl sterols and high molecular weight (HMW) n-alkanols are 11.0 micrograms/g and 2.8 micrograms/g, respectively. Sterols are found at highest levels in areas of enhanced urban outfalls. They can be related to major planktonic species growing in riverine waters. Stanol/stenol ratios suggest a high degree of alteration of the autochthonous OM as a result of elevated temperatures and microbiological proliferation. Even though sterols suggest the importance of autochthonous inputs to the river, HMW n-alkanols indicate major terrigenous accumulation at the mouth and 10 km upriver. Coprostanol and epicoprostanol levels are comparable to other sewage contaminated hydrosystems, but not as high as expected given the importance of sewage outfalls and low riverine water discharge. However, high (coprostanol)/(coprostanol + cholestanol) ratio values indicate that fecal contamination is significant.

  15. Safety of long-term consumption of plant sterol esters-enriched spread

    NARCIS (Netherlands)

    Hendriks, H.F.J.; Brink, E.J.; Meijer, G.W.; Princen, H.M.G.; Ntanios, F.Y.

    2003-01-01

    Objective: To evaluate both efficacy and safety in humans of long-term consumption of spreads containing plant sterol esters. Design: Randomized double-blind placebo-controlled parallel trial. Subjects: Hundred and eighty-five healthy volunteers (35-64y). Intervention: Volunteers daily consumed 20g

  16. [Using plant sterols in clinical practice: From the chemistry to the clinic].

    Science.gov (United States)

    Meco López, José Félix; Pascual Fuster, Vicente; Solà Alberich, Rosa

    This paper describes what are plant sterols, the chemical structure to understand their mechanism of cholesterol-lowering action, and indications and contraindications in clinical practice. Copyright © 2016 Sociedad Española de Arteriosclerosis. Publicado por Elsevier España, S.L.U. All rights reserved.

  17. Sterol homeostasis requires regulated degradation of squalene monooxygenase by the ubiquitin ligase Doa10/Teb4

    DEFF Research Database (Denmark)

    Foresti, Ombretta; Ruggiano, Annamaria; Hannibal-Bach, Hans K

    2013-01-01

    ligase implicated in a branch of the endoplasmic reticulum (ER)-associated protein degradation (ERAD) pathway. Since the other branch of ERAD is required for HMGR regulation, our results reveal a fundamental role for ERAD in sterol homeostasis, with the two branches of this pathway acting together...

  18. Sardisterol, A New Polyhydroxylated Sterol from the Soft Coral Sarcophyton digitatum Moser

    Institute of Scientific and Technical Information of China (English)

    SU, Jing-Yu; YANG, Ruo-Lin

    2001-01-01

    A new polyhydroxylated sterol, named sardisterol, was isolated from the soft coral Sarcophyton digitatum Moser. Its structure was determined as (22R, 24ξ)-methyicholest-5-en-3β,22, 25, 28-tetraol-3-acetate on the basis of spectroscopic methods.

  19. Sterol and sesquiterpenoid biosynthesis during a growth cycle of tobacco cell suspension cultures.

    Science.gov (United States)

    Chappell, J; Von Lanken, C; Vögeli, U; Bhatt, P

    1989-05-01

    The accumulation and biosynthesis of sterols and fungal elicitor-inducible sesquiterpenoids by tobacco (Nicotiana tabacum) cell suspension cultures were examined as a function of a 10 day culture cycle. Sterols accumulated concomitantly with fresh weight gain. The rate of sterol biosynthesis, measured as the incorporation rate of [(14)C]acetate and [(3)H]mevalonate, was maximal when the cultures entered into their rapid phase of growth. Changes in squalene synthetase enzyme activity correlated more closely with thein vivo synthesis rate and accumulation of sterols than 3-hydroxy-3-methylglutaryl CoA reductase (HMGR) enzyme activity. Cell cultures entering into the rapid phase of growth also responded maximally to fungal elicitor as measured by the production of capsidiol, an extracellular sesquiterpenoid. However, the rate of sesquiterpenoid biosynthesis, measured as the incorporation rate of [(14)C]acetate and [(3)H]mevalonate, could not be correlated with elicitor-inducible HMGR or sesquiterpene cyclase enzyme activities, nor elicitor-suppressible squalene synthetase enzyme activity.

  20. Effects of plant sterols and olive oil phenols on serum lipoproteins in humans

    NARCIS (Netherlands)

    Vissers, M.N.

    2001-01-01

    The studies described in this thesis investigated whether minor components from vegetable oils can improve health by decreasing cholesterol concentrations or oxidative modification of low-density-lipoprotein (LDL) particles.The plant sterolsβ-sitosterol and sitostanol are known to decrease cholester

  1. Sterol-dependent nuclear import of ORP1S promotes LXR regulated trans-activation of apoE

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sungsoo, E-mail: sungsoo.lee@utsouthwestern.edu [Departments of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039 (United States); Wang, Ping-Yuan [Departments of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039 (United States); Jeong, Yangsik; Mangelsdorf, David J. [Departments of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041 (United States); Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041 (United States); Anderson, Richard G.W. [Departments of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039 (United States); Michaely, Peter, E-mail: peter.michaely@utsouthwestern.edu [Departments of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039 (United States)

    2012-10-01

    Oxysterol binding protein related protein 1S (ORP1S) is a member of a family of sterol transport proteins. Here we present evidence that ORP1S translocates from the cytoplasm to the nucleus in response to sterol binding. The sterols that best promote nuclear import of ORP1S also activate the liver X receptor (LXR) transcription factors and we show that ORP1S binds to LXRs, promotes binding of LXRs to LXR response elements (LXREs) and specifically enhances LXR-dependent transcription via the ME.1 and ME.2 enhancer elements of the apoE gene. We propose that ORP1S is a cytoplasmic sterol sensor, which transports sterols to the nucleus and promotes LXR-dependent gene transcription through select enhancer elements. -- Highlights: Black-Right-Pointing-Pointer ORP1S translocates to the nucleus in response to sterol binding. Black-Right-Pointing-Pointer The sterols that best promote nuclear import of ORP1S are LXR agonists. Black-Right-Pointing-Pointer ORP1S binds to LXRs, enhances binding of LXRs to LXREs and promotes LXR-dependent transcription of apoE.

  2. Synthesis of Hydroxylated Sterols in Transgenic Arabidopsis Plants Alters Growth and Steroid Metabolism1[C][W][OA

    Science.gov (United States)

    Beste, Lisa; Nahar, Nurun; Dalman, Kerstin; Fujioka, Shozo; Jonsson, Lisbeth; Dutta, Paresh C.; Sitbon, Folke

    2011-01-01

    To explore mechanisms in plant sterol homeostasis, we have here increased the turnover of sterols in Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum) plants by overexpressing four mouse cDNA encoding cholesterol hydroxylases (CHs), hydroxylating cholesterol at the C-7, C-24, C-25, or C-27 positions. Compared to the wild type, the four types of Arabidopsis transformant showed varying degrees of phenotypic alteration, the strongest one being in CH25 lines, which were dark-green dwarfs resembling brassinosteroid-related mutants. Gas chromatography-mass spectrometry analysis of extracts from wild-type Arabidopsis plants revealed trace levels of α and β forms of 7-hydroxycholesterol, 7-hydroxycampesterol, and 7-hydroxysitosterol. The expected hydroxycholesterol metabolites in CH7-, CH24-, and CH25 transformants were identified and quantified using gas chromatography-mass spectrometry. Additional hydroxysterol forms were also observed, particularly in CH25 plants. In CH24 and CH25 lines, but not in CH7 ones, the presence of hydroxysterols was correlated with a considerable alteration of the sterol profile and an increased sterol methyltransferase activity in microsomes. Moreover, CH25 lines contained clearly reduced levels of brassinosteroids, and displayed an enhanced drought tolerance. Equivalent transformations of potato plants with the CH25 construct increased hydroxysterol levels, but without the concomitant alteration of growth and sterol profiles observed in Arabidopsis. The results suggest that an increased hydroxylation of cholesterol and/or other sterols in Arabidopsis triggers compensatory processes, acting to maintain sterols at adequate levels. PMID:21746809

  3. Dissecting the sterol C-4 demethylation process in higher plants. From structures and genes to catalytic mechanism.

    Science.gov (United States)

    Rahier, Alain

    2011-03-01

    Sterols become functional only after removal of the two methyl groups at C-4. This review focuses on the sterol C-4 demethylation process in higher plants. An intriguing aspect in the removal of the two C-4 methyl groups of sterol precursors in plants is that it does not occur consecutively as it does in yeast and animals, but is interrupted by several enzymatic steps. Each C-4 demethylation step involves the sequential participation of three individual enzymatic reactions including a sterol methyl oxidase (SMO), a 3β-hydroxysteroid-dehydrogenase/C4-decarboxylase (3βHSD/D) and a 3-ketosteroid reductase (SR). The distant location of the two C-4 demethylations in the sterol pathway requires distinct SMOs with respective substrate specificity. Combination of genetic and molecular enzymological approaches allowed a thorough identification and functional characterization of two distinct families of SMOs genes and two 3βHSD/D genes. For the latter, these studies provided the first molecularly and functionally characterized HSDs from a short chain dehydrogenase/reductase family in plants, and the first data on 3-D molecular interactions of an enzyme of the postoxidosqualene cyclase sterol biosynthetic pathway with its substrate in animals, yeast and higher plants. Characterization of these three new components involved in C-4 demethylation participates to the completion of the molecular inventory of sterol synthesis in higher plants.

  4. Effect of unialgal diets on the composition of fatty acids and sterols in juvenile ark shell Tegillarca granosa Linnaeus.

    Science.gov (United States)

    Xu, Jilin; Zhou, Haibo; Yan, Xiaojun; Zhou, Chengxu; Zhu, Peng; Ma, Bin

    2012-04-18

    This study has investigated the effects of six different unialgal diets ( Chaetoceros calcitrans , Platymonas helgolandica , Chlorella sp., Isochrysis galbana , Nannochloropsis oculata , and Pavlova viridis ) on the composition of fatty acids and sterols in juvenile ark shell Tegillarca granosa Linnaeus. The best feeding effects on the growth of shellfish were found in C. calcitrans, followed by I. galbana and P. viridis, whereas Chlorella sp. and N. oculata exhibited relatively poor effects. The fatty acid and sterol compositions in the six microalgae and the juvenile ark shell after feeding were analyzed, and 39 fatty acids and 18 sterols were identified. Although the results demonstrate a close correlation between the sterol compositions in algal species and juvenile ark shell, a similar correlation was not observed between fatty acids. In the juvenile ark shell fed microalgae, the ratio of total saturated fatty acids (SFA) rapidly decreases, whereas the proportion of total polyunsaturated fatty acids (PUFAs) increases considerably. The abundances of AA, EPA, and DHA increase most significantly in shellfish with better growth (fed C. calcitrans, I. galbana, and P. viridis). The number of sterol species is reduced, but the total sterol content in groups fed corresponding microalgae increases, and abundant plant sterols, instead of cholesterol, are accumulated in juvenile ark shell fed appropriate microalgae I. galbana and P. viridis. Therefore, to be more conducive to human health, I. galbana and P. viridis, of the six experimental microalgae, are recommended for artificial ark shell culture.

  5. Increased sesquiterpenoid biosynthesis and an apparent decrease in sterol biosynthesis in elicitor-treated tobacco cell suspension cultures

    Energy Technology Data Exchange (ETDEWEB)

    Voegeli, U.; Bhatt, P.N.; Chappell, J.

    1987-04-01

    Addition of fungel elicitor prepared from Phytophthora parasitica to tobacco cell suspension cultures leads to an increased production of the phytoalexin capsidiol. Capsidiol is a sesquiterpenoid which is most likely synthesized from farnesylpyrophosphat (FPP) by a bicyclic cyclase reaction. Because FPP is also a substrate for squalene synthetase and therefore a precursor of sterol biosynthesis, the question arises whether or not the accumulation of capsidiol in elicitor-treated cells occurs at the expense of sterol biosynthesis. (/sup 14/C)-acetate was given to elicitor-treated and control (no treatment) cell cultures and incorporation into sterols and capsidiol determined. No labeled capsidiol was detected in control cells. In elicitor-treated cells about 12-15% of the radioactivity taken up by the cells was incorporated into capsidiol. In contrast, control cells incorporated 4 times more radioactivity into sterols than elicitor-treated cells. Similar results were obtained using (/sup 3/H)-mevalonate as a precursor of capsidiol and sterol biosynthesis. Likely explanations for the apparently decline in sterol biosynthesis in elicitor-treated cells include: (1) inhibition of squalene synthetase; (2) induction of capsidiol synthesizing enzymes; and (3) metabolic channeling of FPP into capsidiol versus sterols. These possibilities will be discussed further together with other results.

  6. Dissociated sterol-based liver X receptor agonists as therapeutics for chronic inflammatory diseases.

    Science.gov (United States)

    Yu, Shan; Li, Sijia; Henke, Adam; Muse, Evan D; Cheng, Bo; Welzel, Gustav; Chatterjee, Arnab K; Wang, Danling; Roland, Jason; Glass, Christopher K; Tremblay, Matthew

    2016-07-01

    Liver X receptor (LXR), a nuclear hormone receptor, is an essential regulator of immune responses. Activation of LXR-mediated transcription by synthetic agonists, such as T0901317 and GW3965, attenuates progression of inflammatory disease in animal models. However, the adverse effects of these conventional LXR agonists in elevating liver lipids have impeded exploitation of this intriguing mechanism for chronic therapy. Here, we explore the ability of a series of sterol-based LXR agonists to alleviate inflammatory conditions in mice without hepatotoxicity. We show that oral treatment with sterol-based LXR agonists in mice significantly reduces dextran sulfate sodium colitis-induced body weight loss, which is accompanied by reduced expression of inflammatory markers in the large intestine. The anti-inflammatory property of these agonists is recapitulated in vitro in mouse lamina propria mononuclear cells, human colonic epithelial cells, and human peripheral blood mononuclear cells. In addition, treatment with LXR agonists dramatically suppresses inflammatory cytokine expression in a model of traumatic brain injury. Importantly, in both disease models, the sterol-based agonists do not affect the liver, and the conventional agonist T0901317 results in significant liver lipid accumulation and injury. Overall, these results provide evidence for the development of sterol-based LXR agonists as novel therapeutics for chronic inflammatory diseases.-Yu, S., Li, S., Henke, A., Muse, E. D., Cheng, B., Welzel, G., Chatterjee, A. K., Wang, D., Roland, J., Glass, C. K., Tremblay, M. Dissociated sterol-based liver X receptor agonists as therapeutics for chronic inflammatory diseases.

  7. The relative effect of sterols and hopanoids on lipid bilayers: when comparable is not identical.

    Science.gov (United States)

    Poger, David; Mark, Alan E

    2013-12-19

    Sterols are the hallmarks of eukaryotic membranes where they are often found in specialized functional microdomains of the plasma membrane called lipid rafts. Despite some notable exceptions, prokaryotes lack sterols. However, growing evidence has suggested the existence of raft-like domains in the plasma membrane of bacteria. A structurally related family of triterpenoids found in some bacteria called hopanoids has long been assumed to be bacterial surrogates for sterols in membranes. Although the effect of sterols, in particular cholesterol, on lipid bilayers has been extensively characterized through experimental and simulation studies, those of hopanoids have hardly been investigated. In this study, molecular dynamics simulations are used to examine the effect of two hopanoids, diploptene (hop-22(29)-ene) and bacteriohopanetetrol ((32R,33S,34S)-bacteriohopane-32,33,34,35-tetrol), on a model bilayer. The results are compared with those obtained for cholesterol and a pure phosphatidylcholine bilayer. It is shown that diploptene and bacteriohopanetetrol behave very differently under the conditions simulated. Whereas bacteriohopanetetrol adopted a cholesterol-like upright orientation in the bilayer, diploptene partitioned between the two leaflets inside the bilayer. Analysis of various structural properties (area per lipid, electron density profile, tilt angle of the lipids, and conformation and order parameters of the phosphatidylcholine tails) in bacteriohopanetetrol- and cholesterol-containing bilayers indicates that the condensing and ordering effect of bacteriohopanetetrol is weaker than that of cholesterol. The simulations suggest that the chemical diversity of hopanoids may lead to a broader range of functional roles in bacterial membranes than sterols in eukaryotic membranes.

  8. Glucal-conjugated sterols as novel vascular leakage blocker: structure-activity relationship focusing on the C17-side chain.

    Science.gov (United States)

    Kim, Kyeojin; Maharjan, Sony; Lim, Changjin; Kim, Nam-Jung; Agrawal, Vijayendra; Han, Young Taek; Lee, Sujin; An, Hongchan; Yun, Hwayoung; Choi, Hyun-Jung; Kwon, Young-Guen; Suh, Young-Ger

    2014-03-21

    A series of glucal-conjugated sterols as novel vascular leakage blocker were identified through design, synthesis and biologically evaluation. In addition, the structure-activity relationship (SAR) of the glucal-conjugated sterols focusing on the C17-side chain was also established. The sterol analogs linked with the rigid C17-side chain side chains exhibited potent cell survival activities. In particular, analog 21l, which possesses a cyclopentyl oxime moiety, was shown to have excellent pharmacological effects on retinal vascular leakage in a diabetic mouse model. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  9. Regulation of Calcium-Independent Phospholipase A2 Expression by Adrenoceptors and Sterol Regulatory Element Binding Protein-Potential Crosstalk Between Sterol and Glycerophospholipid Mediators.

    Science.gov (United States)

    Chew, Wee-Siong; Ong, Wei-Yi

    2016-01-01

    Calcium-independent phospholipase A2 (iPLA2) is an 85-kDa enzyme that releases docosahexaenoic acid (DHA) from glycerophospholipids. DHA can be metabolized to resolvins and neuroprotectins that have anti-inflammatory properties and effects on neural plasticity. Recent studies show an important role of prefrontal cortical iPLA2 in hippocampo-prefrontal cortical LTP and antidepressant-like effect of the norepinephrine reuptake inhibitor (NRI) antidepressant, maprotiline. In this study, we elucidated the cellular mechanisms through which stimulation of adrenergic receptors could lead to increased iPLA2 expression. Treatment of SH-SY5Y neuroblastoma cells with maprotiline, another tricyclic antidepressant with noradrenaline reuptake inhibiting properties, nortriptyline, and the adrenergic receptor agonist, phenylephrine, resulted in increased iPLA2β mRNA expression. This increase was blocked by inhibitors to alpha-1 adrenergic receptor, mitogen-activated protein (MAP) kinase or extracellular signal-regulated kinase (ERK) 1/2, and sterol regulatory element-binding protein (SREBP). Maprotiline and phenylephrine induced binding of SREBP-2 to sterol regulatory element (SRE) region on the iPLA2 promoter, as determined by electrophoretic mobility shift assay (EMSA). Together, results indicate that stimulation of adrenoreceptors causes increased iPLA2 expression via MAP kinase/ERK 1/2 and SREBP, and suggest a possible mechanism for effect of CNS noradrenaline on neural plasticity and crosstalk between sterol and glycerophospholipid mediators, that may play a role in physiological or pathophysiological processes in the brain and other organs.

  10. The effects of growth temperature on the methyl sterol and phospholipid fatty acid composition of Methylococcus capsulatus (Bath)

    Science.gov (United States)

    Jahnke, L. L.

    1992-01-01

    Growth of Methylococcus capsulatus (Bath) at temperatures ranging from 30 to 50 degrees C resulted in changes to the whole cell lipid constituents. As temperature was lowered, the overall proportion of hexadecenoic acid (C16:1) increased, and the relative proportions of the delta 9, delta 10 and delta 11 C16:1 double bond positional isomers changed. Methyl sterol content also increased as the growth temperature was lowered. The highest amounts of methyl sterol were found in 30 degrees C cells and the lowest in 50 degrees C cells (sterol-phospholipid ratios of 0.077 and 0.013, respectively). The data are consistent with a membrane modulating role for the sterol produced by this prokaryotic organism.

  11. Structural Features and Potent Antidepressant Effects of Total Sterols and β-sitosterol Extracted from Sargassum horneri.

    Science.gov (United States)

    Zhao, Donghai; Zheng, Lianwen; Qi, Ling; Wang, Shuran; Guan, Liping; Xia, Yanan; Cai, Jianhui

    2016-06-28

    The purified total sterols and β-sitosterol extracted from Sargassum horneri were evaluated for their antidepressant-like activity using the forced swim test (FST) and tail suspension test (TST) in mice. Total sterols and β-sitosterol significantly reduced the immobility time in the FST and TST. Total sterols were administered orally for 7 days at doses of 50, 100, and 200 mg/kg, and β-sitosterol was administered intraperitoneally at doses of 10, 20, and 30 mg/kg. β-sitosterol had no effect on locomotor activity in the open field test. In addition, total sterols and β-sitosterol significantly increased NE, 5-HT, and the metabolite 5-HIAA in the mouse brain, suggesting that the antidepressant-like activity may be mediated through these neurotransmitters.

  12. Baseline concentrations of faecal sterols and assessment of sewage input into different inlets of Admiralty Bay, King George Island, Antarctica.

    Science.gov (United States)

    Martins, César C; Aguiar, Sabrina N; Wisnieski, Edna; Ceschim, Liziane M M; Figueira, Rubens C L; Montone, Rosalinda C

    2014-01-15

    The Antarctic region is one of the best preserved environments in the world. However, human activities such as the input of sewage result in the alteration of this pristine site. We report baseline values of faecal sterols in Admiralty Bay, Antarctica. Four sediment cores were collected during the 2006/2007 austral summer at the Ezcurra (THP and BAR), Mackelar (REF) and Martel (BTP) inlets. Concentrations of faecal sterols (coprostanol+epicoprostanol) were sterols in core layers for THP, BAR, REF and BTP, were 0.04 ± 0.02, 0.03 ± 0.01, 0.07 ± 0.01 and 0.04 ± 0.02 μg g(-1), respectively. These results established as natural contributions of faecal sterols, suggesting that these markers can be useful indicators of human-derived faecal input and contributing to monitoring programs to prevent anthropogenic impacts. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. The effects of growth temperature on the methyl sterol and phospholipid fatty acid composition of Methylococcus capsulatus (Bath)

    Science.gov (United States)

    Jahnke, Linda L.

    1992-01-01

    Growth of Methylococcus capsulatus (Bath) at temperatures ranging from 30 to 50 C resulted in changes to the whole cell lipid constituents. As temperature was lowered, the overall proportion of hexadecenoic acid (C16:1) increased, and the relative proportions of the Delta9, Delta10, and Delta11 C16:1 double bond positional isomers changed. Methyl sterol content also increased as the growth temperature was lowered. The highest amounts of methyl sterol were found in 30 C cells and the lowest in 50 C cells (sterol-phospholipid ratios of 0.077 and 0.013, respectively). The data are consistent with a membrane modulating role for the sterol produced by this prokaryotic organism.

  14. Structural Features and Potent Antidepressant Effects of Total Sterols and β-sitosterol Extracted from Sargassum horneri

    Directory of Open Access Journals (Sweden)

    Donghai Zhao

    2016-06-01

    Full Text Available The purified total sterols and β-sitosterol extracted from Sargassum horneri were evaluated for their antidepressant-like activity using the forced swim test (FST and tail suspension test (TST in mice. Total sterols and β-sitosterol significantly reduced the immobility time in the FST and TST. Total sterols were administered orally for 7 days at doses of 50, 100, and 200 mg/kg, and β-sitosterol was administered intraperitoneally at doses of 10, 20, and 30 mg/kg. β-sitosterol had no effect on locomotor activity in the open field test. In addition, total sterols and β-sitosterol significantly increased NE, 5-HT, and the metabolite 5-HIAA in the mouse brain, suggesting that the antidepressant-like activity may be mediated through these neurotransmitters.

  15. Structural Features and Potent Antidepressant Effects of Total Sterols and β-sitosterol Extracted from Sargassum horneri

    Science.gov (United States)

    Zhao, Donghai; Zheng, Lianwen; Qi, Ling; Wang, Shuran; Guan, Liping; Xia, Yanan; Cai, Jianhui

    2016-01-01

    The purified total sterols and β-sitosterol extracted from Sargassum horneri were evaluated for their antidepressant-like activity using the forced swim test (FST) and tail suspension test (TST) in mice. Total sterols and β-sitosterol significantly reduced the immobility time in the FST and TST. Total sterols were administered orally for 7 days at doses of 50, 100, and 200 mg/kg, and β-sitosterol was administered intraperitoneally at doses of 10, 20, and 30 mg/kg. β-sitosterol had no effect on locomotor activity in the open field test. In addition, total sterols and β-sitosterol significantly increased NE, 5-HT, and the metabolite 5-HIAA in the mouse brain, suggesting that the antidepressant-like activity may be mediated through these neurotransmitters. PMID:27367705

  16. Cholesterol lowering effect of a soy drink enriched with plant sterols in a French population with moderate hypercholesterolemia

    Directory of Open Access Journals (Sweden)

    Bard Jean-Marie

    2008-10-01

    Full Text Available Abstract Background Plant sterols are an established non-pharmacological means to reduce total and LDL blood cholesterol concentrations and are therefore recommended for cholesterol management by worldwide-renown health care institutions. Their efficacy has been proven in many types of foods with the majority of trials conducted in spreads or dairy products. As an alternative to dairy products, soy based foods are common throughout the world. Yet, there is little evidence supporting the efficacy of plant sterols in soy-based foods. The objective of this study was to investigate the effect of a soy drink enriched with plant sterols on blood lipid profiles in moderately hypercholesterolemic subjects. Methods In a randomized, placebo-controlled double-blind mono-centric study, 50 subjects were assigned to 200 ml of soy drink either enriched with 2.6 g plant sterol esters (1.6 g/d free plant sterol equivalents or without plant sterols (control for 8 weeks. Subjects were instructed to maintain stable diet pattern and physical activity. Plasma concentrations of lipids were measured at initial visit, after 4 weeks and after 8 weeks. The primary measurement was the change in LDL cholesterol (LDL-C. Secondary measurements were changes in total cholesterol (TC, non-HDL cholesterol (non-HDL-C, HDL cholesterol (HDL-C and triglycerides. Results Regular consumption of the soy drink enriched with plant sterols for 8 weeks significantly reduced LDL- C by 0.29 mmol/l or 7% compared to baseline (p 96%, and products were well tolerated. Conclusion Daily consumption of a plant sterol-enriched soy drink significantly decreased total, non-HDL and LDL cholesterol and is therefore an interesting and convenient aid in managing mild to moderate hypercholesterolemia.

  17. Methyl sterol and cyclopropane fatty acid composition of Methylococcus capsulatus grown at low oxygen tensions

    Science.gov (United States)

    Jahnke, L. L.; Nichols, P. D.

    1986-01-01

    The sterol and fatty acid concentrations for M. capsulatus grown in fed-batch cultures over a wide range of oxygen tensions (0.1-10.6 percent) and at a constant methane level are evaluated. The analyses reveal that the biomass decreases as oxygen levels are lowered; the sterol concentration increases when the oxygen range is between 0.5-1.1 percent and decreases when the oxygen range is below 0.5 percent; and the amount of monounsaturated C16 decreases and the concentration of cyclopropane fatty acids increases after oxygen is reduced. It is noted that growth and membrane synthesis occur at low oxygen concentrations and that the synthesis of membrane lipids responds to growth conditions.

  18. Microbial water quality and sedimentary faecal sterols as markers of sewage contamination in Kuwait.

    Science.gov (United States)

    Lyons, B P; Devlin, M J; Abdul Hamid, S A; Al-Otiabi, A F; Al-Enezi, M; Massoud, M S; Al-Zaidan, A S; Smith, A J; Morris, S; Bersuder, P; Barber, J L; Papachlimitzou, A; Al-Sarawi, H A

    2015-11-30

    Microbial water quality and concentrations of faecal sterols in sediment have been used to assess the degree of sewage contamination in Kuwait's marine environment. A review of microbial (faecal coliform, faecal streptococci and Escherichia coli) water quality data identified temporal and spatial sources of pollution around the coastline. Results indicated that bacterial counts regularly breach regional water quality guidelines. Sediments collected from a total of 29 sites contained detectable levels of coprostanol with values ranging from 29 to 2420 ng g(-1) (dry weight). Hot spots based on faecal sterol sediment contamination were identified in Doha Bay and Sulaibikhat Bay, which are both smaller embayments of Kuwait Bay. The ratio of epicoprostanol/coprostanol indicates that a proportion of the contamination was from raw or partially treated sewage. Sewage pollution in these areas are thought to result from illegal connections and discharges from storm drains, such as that sited at Al-Ghazali.

  19. The Hypoxic Regulator of Sterol Synthesis Nro1 Is a Nuclear Import Adaptor

    Energy Technology Data Exchange (ETDEWEB)

    T Yeh; C Lee; L Amzel; P Espenshade; M Bianchet

    2011-12-31

    Fission yeast protein Sre1, the homolog of the mammalian sterol regulatory element-binding protein (SREBP), is a hypoxic transcription factor required for sterol homeostasis and low-oxygen growth. Nro1 regulates the stability of the N-terminal transcription factor domain of Sre1 (Sre1N) by inhibiting the action of the prolyl 4-hydroxylase-like Ofd1 in an oxygen-dependent manner. The crystal structure of Nro1 determined at 2.2 {angstrom} resolution shows an all-{alpha}-helical fold that can be divided into two domains: a small N-terminal domain, and a larger C-terminal HEAT-repeat domain. Follow-up studies showed that Nro1 defines a new class of nuclear import adaptor that functions both in Ofd1 nuclear localization and in the oxygen-dependent inhibition of Ofd1 to control the hypoxic response.

  20. Impact of Lipid Components and Emulsifiers on Plant Sterols Bioaccessibility from Milk-Based Fruit Beverages.

    Science.gov (United States)

    Alvarez-Sala, Andrea; Garcia-Llatas, Guadalupe; Cilla, Antonio; Barberá, Reyes; Sánchez-Siles, Luis Manuel; Lagarda, María Jesús

    2016-07-20

    Sterol bioaccessibility (BA) of three plant sterol (PS)-enriched milk-based fruit beverages (MFb) with different fat contents (1.1-2.4%), lipid sources (animal or vegetable), and without or with emulsifiers (whey proteins enriched with milk fat globule membrane (MFGM) or soy lecithin) was evaluated after simulated gastrointestinal digestion. The BA of total PS followed the order 31.4% (MFbM containing milk fat and whey proteins enriched with MFGM) = 28.2% (MFbO containing extra virgin olive oil and soy lecithin) > 8.7% (MFb without fat addition). Total and individual PS content in the bioaccessible fractions followed the order MFbM > MFbO > MFb. Consequently, formulation with MFGM is proposed in beverages of this kind to ensure optimum bioavailability of PS. Our results suggest that the BA of PS is influenced by the type and quantity of fat and the emulsifier type involved.

  1. Parameters for Martini sterols and hopanoids based on a virtual-site description

    Science.gov (United States)

    Melo, M. N.; Ingólfsson, H. I.; Marrink, S. J.

    2015-12-01

    Sterols play an essential role in modulating bilayer structure and dynamics. Coarse-grained molecular dynamics parameters for cholesterol and related molecules are available for the Martini force field and have been successfully used in multiple lipid bilayer studies. In this work, we focus on the use of virtual sites as a means of increasing the stability of cholesterol and cholesterol-like structures. We improve and extend the Martini parameterization of sterols in four different ways: 1—the cholesterol parameters were adapted to make use of virtual interaction sites, which markedly improves numerical stability; 2—cholesterol parameters were also modified to address reported shortcomings in reproducing correct lipid phase behavior in mixed membranes; 3—parameters for ergosterol were created and adapted from cholesterols; and 4—parameters for the hopanoid class of bacterial polycyclic molecules were created, namely, for hopane, diploptene, bacteriohopanetetrol, and for their polycyclic base structure.

  2. Cytotoxic 5α,8α-epidioxy sterols from the marine sponge Monanchora sp.

    Science.gov (United States)

    Mun, Bora; Wang, Weihong; Kim, Hiyoung; Hahn, Dongyup; Yang, Inho; Won, Dong Hwan; Kim, Eun-hee; Lee, Jihye; Han, Chulkyeong; Kim, Hyunji; Ekins, Merrick; Nam, Sang-Jip; Choi, Hyukjae; Kang, Heonjoong

    2015-01-01

    Three new sterols, 5α,8α-epidioxy-24-norcholesta-6,9(11),22-trien-3β-ol (1), 5α,8α-epidioxy-cholesta-6,9(11),24-trien-3β-ol (2), and 5α,8α-epidioxy-cholesta-6,23-dien-3β,25-diol (3), with four known sterols (4-7) were isolated from a marine sponge Monanchora sp. Their chemical structures were elucidated by extensive spectroscopic analysis. Compounds 1 and 3-7 showed moderate cytotoxicity against several human carcinoma cell lines including renal (A-498), pancreatic (PANC-1 and MIA PaCa-2), and colorectal (HCT 116) cancer cell lines.

  3. The effect of a combination of plant sterol-enriched foods in mildly hypercholesterolemic subjects.

    Science.gov (United States)

    Madsen, Martin B; Jensen, Anne-Mette; Schmidt, Erik B

    2007-12-01

    The purpose of this study was to evaluate the effect of low-fat products enriched with plant sterols in addition to a National Cholesterol Education Program step 1 diet on serum lipids and lipoproteins. This study was a double-blind, randomised, placebo-controlled cross-over design with a run-in period and 2 intervention periods, each lasting 4 weeks. A total of 46 mildly hypercholesterolemic subjects (age 50.6+/-9.8) completed the trial. The study products consisted of 20 g low-fat margarine (35% fat) and 250 ml low-fat milk (0.7% fat), in total delivering 2.3g plant sterols/d. Serum total and low-density lipoprotein cholesterol were significantly reduced by 5.5% (pUnilever Denmark A/S.

  4. Fatty acid and sterol contents during tulip leaf senescence induced by methyl jasmonate

    Directory of Open Access Journals (Sweden)

    Marian Saniewski

    2013-12-01

    Full Text Available It has been shown previously that methyl jasmonate (JA-Me applied in lanolin paste on the bottom surface of intact tulip leaves causes a rapid and intense its senescence. The aim of this work was to study the effect of JA-Me on free and bound fatty acid and sterol contents during tulip leaf senescence. The main free and bound fatty acids of tulip leaf, in decreasing order of their abundance, were linolenic, linoleic, palmitic, oleic, stearic and myristic acids. Only the content of free linolenic acid decreased after treatment with JA-Me during visible stage of senescence. ß-Sitosterol (highest concentration, campesterol, stigmasterol and cholesterol were identified in tulip leaf. Methyl jasmonate evidently increased the level of ß-sitosterol, campesterol and stigmasterol during induced senescence. It is suggested that the increase in sterol concentrations under the influence of methyl jasmonate induced changes in membrane fluidity and permeability, which may be responsible for senescence.

  5. Arenicolsterol A, a Novel Cytotoxic Enolic Sulfated Sterol from a Marine Annelid Arenicola cristata

    Institute of Scientific and Technical Information of China (English)

    CHEN Bin; SHEN Xian-Rong; KONG Ji-Lie

    2005-01-01

    Marine organisms are the important source of the bioactive metabolites. A novel enolic sulfated sterol, arenicolsterol A, has been isolated from a marine annelid Arenicola cristata collected in the coast of Mainland of China.The structure was elucidated using all sorts of spectroscopic data including ESIMS, 1D and 2D NMR etc. The cytotoxic bioactivity of this sterol was evaluated by MTT assay. It could inhibit the growth of human cervix cancer cell line (Hela) and human non-small cell lung cancer cell line (NCI-h6) with IC50 of (3.1 ±0.6) μg/mL and (7.6±0.8) μg/mL.

  6. [Terpenoids and sterols from Ricinus communis and their activities against diabetes].

    Science.gov (United States)

    Li, Shen-Hua; Deng, Qing; Zhu, Li; Lai, Chun-Hua; Wang, Heng-Shan; Tan, Qin-Gang

    2014-02-01

    Seven terpenoids and three sterols were isolated from the methanol extracts of the aerial parts of Ricinus communis by chromatography methods and their structures were identified by spectra analysis as ficusic acid( 1), phytol(2), callyspinol(3) , lupeol(4), 30-norlupan-3beta-ol-20-one(5) , lup-20(29)-en-3beta,15alpha-diol(6) , acetylaleuritolic acid( 7), stigmast4-en-3-one(8) , stig-mast-4-en-6beta-ol-3-one(9) , and stigmast4-en-3,6-dione(10). Compounds 1-3 and 5-10 were obtained from this species for the first time and 5 and 6 showed significant inhibitive activity and good selectivity against 11beta-HSD of mouse and human in vitro. [Key words] Ricinus communis; terpenoids; sterols; 11beta-HSD

  7. Vesicle fluctuation analysis of the effects of sterols on membrane bending rigidity

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Rowat, Amy C.; Ipsen, John H.

    2004-01-01

    Sterols are regulators of both biological function and structure. The role of cholesterol in promoting the structural and mechanical stability of membranes is widely recognized. Knowledge of how the related sterols, lanosterol and ergosterol, affect membrane mechanical properties is sparse. This ...... on vesicle behaviour are also discussed. These recent modifications render vesicle fluctuation analysis an efficient and accurate method for determining how cholesterol, lanosterol, and ergosterol increase membrane bending rigidity........ This paper presents a comprehensive comparison of the effects of cholesterol, lanosterol, and ergosterol upon the bending elastic properties of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine giant unilamellar vesicles. Measurements are made using vesicle fluctuation analysis, a nonintrusive technique...... that we have recently improved for determining membrane bending rigidity. Giving a detailed account of the vesicle fluctuation analysis technique, we describe how the gravitational stabilization of the vesicles enhances image contrast, vesicle yield, and the quality of data. Implications of gravity...

  8. Vesicle fluctuation analysis of the effects of sterols on membrane bending rigidity

    DEFF Research Database (Denmark)

    Henriksen, J.; Rowat, Amy Catherine; Ipsen, John Hjorth

    2004-01-01

    Sterols are regulators of both biological function and structure. The role of cholesterol in promoting the structural and mechanical stability of membranes is widely recognized. Knowledge of how the related sterols, lanosterol and ergosterol, affect membrane mechanical properties is sparse. This ...... on vesicle behaviour are also discussed. These recent modifications render vesicle fluctuation analysis an efficient and accurate method for determining how cholesterol, lanosterol, and ergosterol increase membrane bending rigidity........ This paper presents a comprehensive comparison of the effects of cholesterol, lanosterol, and ergosterol upon the bending elastic properties of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine giant unilamellar vesicles. Measurements are made using vesicle fluctuation analysis, a nonintrusive technique...... that we have recently improved for determining membrane bending rigidity. Giving a detailed account of the vesicle fluctuation analysis technique, we describe how the gravitational stabilization of the vesicles enhances image contrast, vesicle yield, and the quality of data. Implications of gravity...

  9. Effects of plant stanol ester consumption on fasting plasma oxy(phyto)sterol concentrations as related to fecal microbiota characteristics.

    Science.gov (United States)

    Baumgartner, Sabine; Mensink, Ronald P; Smet, Els De; Konings, Maurice; Fuentes, Susana; de Vos, Willem M; Plat, Jogchum

    2016-03-03

    Information regarding dietary effects on plasma oxyphytosterol concentrations as well as on the origin of oxyphytosterols is scarce. We hypothesized that plant sterols are oxidized in the intestinal lumen, mediated by microbial activity, followed by uptake into the circulation. To address this hypothesis, we carried out, a randomized, double blind, crossover study in 13 healthy subjects, who consumed for 3 weeks control and plant stanol ester enriched margarines (3.0g/d plant stanols) separated by a 4-week wash-out period. Plasma oxy(phyto)sterols were determined via GC-MS/MS, while microbiota analyses were performed on fecal DNA using a phylogenetic microarray to assess microbial composition and diversity. Plasma plant sterol concentrations did not correlate with plasma oxyphytosterols concentrations at baseline. Plant stanol consumption reduced serum sitosterol and campesterol concentrations (-37% and -38%), respectively (pmicrobiota composition and diversity of the faecal contents were not different between the two periods, we observed significant correlations between several specific bacterial groups and plasma plant sterol, but not with plasma oxyphytosterol concentrations. In conclusion, plant stanol ester consumption reduced serum plant sterol and plasma oxyphytosterol concentrations, while intestinal microbiota composition and diversity were not changed. To definitely answer the effects of microbiota on oxyphytosterol formation, future studies could examine oxyphytosterol concentrations after changing intestinal microbial composition or by measuring intestinal oxyphytosterol formation after providing labelled non-oxidized plant sterols.

  10. A novel processing system of sterol regulatory element-binding protein-1c regulated by polyunsaturated fatty acid.

    Science.gov (United States)

    Nakakuki, Masanori; Kawano, Hiroyuki; Notsu, Tatsuto; Imada, Kazunori; Mizuguchi, Kiyoshi; Shimano, Hitoshi

    2014-05-01

    The proteolytic cascade is the key step in transactivation of sterol regulatory element-binding proteins (SREBPs), a transcriptional factor of lipid synthesis. Proteolysis of SREBP-2 is strictly regulated by sterols, but that of SREBP-1c was not strongly sterol-regulated, but inhibited by polyunsaturated fatty acids (PUFAs). In this study, the proteolytic processing of SREBP-1 and -2 was examined by transfection studies of cDNA-encoding mutants in which all the known cleavage sites were disrupted. In cultured cells, sterol-regulated SREBP-2 processing was completely eliminated by mutation of cleavage sites. In contrast, the corresponding SREBP-1c mutants as well as wild type exhibited large amounts of cleaved products in the nuclear extracts from culture cells and murine liver in vivo. The nuclear form of the mutant SREBP-1c was induced by delipidated condition and suppressed by eicosapentaenoic acid, an n-3 PUFA, but not by sterols. This novel processing mechanism was affected by neither SREBP cleavage-activating protein (SCAP) nor insulin-induced gene (Insig)-1, unlike SREBP-2, but abolished by a serine protease inhibitor. Through analysis of deletion mutant, a site-2 protease recognition sequence (DRSR) was identified to be involved in this novel processing. These findings suggest that SREBP-1c cleavage could be subjected to a novel PUFA-regulated cleavage system in addition to the sterol-regulatory SCAP/Insig system.

  11. Structural Sterols Are Involved in Both the Initiation and Tip Growth of Root Hairs in Arabidopsis thaliana[W

    Science.gov (United States)

    Ovečka, Miroslav; Berson, Tobias; Beck, Martina; Derksen, Jan; Šamaj, Jozef; Baluška, František; Lichtscheidl, Irene K.

    2010-01-01

    Structural sterols are abundant in the plasma membrane of root apex cells in Arabidopsis thaliana. They specifically accumulate in trichoblasts during the prebulging and bulge stages and show a polar accumulation in the tip during root hair elongation but are distributed evenly in mature root hairs. Thus, structural sterols may serve as a marker for root hair initiation and growth. In addition, they may predict branching events in mutants with branching root hairs. Structural sterols were detected using the sterol complexing fluorochrome filipin. Application of filipin caused a rapid, concentration-dependent decrease in tip growth. Filipin-complexed sterols accumulated in globular structures that fused to larger FM4-64–positive aggregates in the tip, so-called filipin-induced apical compartments, which were closely associated with the plasma membrane. The plasma membrane appeared malformed and the cytoarchitecture of the tip zone was affected. Trans-Golgi network/early endosomal compartments containing molecular markers, such as small Rab GTPase RabA1d and SNARE Wave line 13 (VTI12), locally accumulated in these filipin-induced apical compartments, while late endosomes, endoplasmic reticulum, mitochondria, plastids, and cytosol were excluded from them. These data suggest that the local distribution and apical accumulation of structural sterols may regulate vesicular trafficking and plasma membrane properties during both initiation and tip growth of root hairs in Arabidopsis. PMID:20841426

  12. Primary hyperlipidemias in children: effect of plant sterol supplementation on plasma lipids and markers of cholesterol synthesis and absorption.

    Science.gov (United States)

    Guardamagna, O; Abello, F; Baracco, V; Federici, G; Bertucci, P; Mozzi, A; Mannucci, L; Gnasso, A; Cortese, C

    2011-06-01

    Plant sterols lower serum cholesterol concentration. Available data have confirmed the lipid-lowering efficacy in adults, while there is a relative dearth of data in children and almost exclusively restricted to subjects with familial hypercholesterolemia (FH). Aim of the present study was to evaluate the efficacy, tolerability and safety of plant sterol supplementation in children with different forms of primary hyperlipidemias. The effect of plant sterol consumption on plasma lipids was evaluated in 32 children with heterozygous FH, 13 children with Familial Combined Hyperlipidemia (FCH) and 13 children with Undefined Hypercholesterolemia (UH) in a 12-week open-label intervention study using plant sterol-enriched yoghurt. Plasma lipids and apolipoproteins were measured by routine methods. Markers of cholesterol synthesis (lathosterol) and absorption (campesterol and sitosterol) were measured by GC-MS. Tolerability and adherence to recommended regimen was very high. A significant reduction was observed in LDL-cholesterol in the three groups (10.7, 14.2 and 16.0% in FH, FCH and UH, respectively). Lathosterol concentrations were unchanged, reflecting a lack of increased synthesis of cholesterol. Of the two absorption markers, only sitosterol showed a slight but significant increase. Daily consumption of plant sterol dairy products favorably changes lipid profile by reducing LDL-cholesterol. To our knowledge, this is the first report of the use of plant sterols-enriched foods in treating children with primary hyperlipidemia such as FCH and UH, likely to be the most frequent form also in the young age in the western populations.

  13. Assessment of Fecal Contamination in Oklahoma Water Systems through the Use of Sterol Fingerprints

    OpenAIRE

    Yueming Lu; R. Paul Philp; Coralie Biache

    2016-01-01

    Fecal contamination is a major concern for water quality management, since the fecal materials are associated with pathogens that can cause illness wherever water is used for recreational, drinking and aquaculture purposes. In order to monitor source(s) of fecal contamination in Oklahoma water systems, sterol profiles were previously examined in rural and urban samples collected from the Illinois River Basin and the Norman Wastewater Treatment Plant (WWTP), respectively. Two distinctive, qual...

  14. Molecular aspects of polyene- and sterol-dependent pore formation in thin lipid membranes.

    Science.gov (United States)

    Dennis, V W; Stead, N W; Andreoli, T E

    1970-03-01

    Amphotericin B modifies the permeability properties of thin lipid membranes formed from solutions containing sheep red cell phospholipids and cholesterol. At 10(-6)M amphotericin B, the DC membrane resistance fell from approximately 10(8) to approximately 10(2) ohm-cm(2), and the membranes became Cl(-)-, rather than Na(+)-selective; the permeability coefficients for hydrophilic nonelectrolytes increased in inverse relationship to solute size, and the rate of water flow during osmosis increased 30-fold. These changes may be rationalized by assuming that the interaction of amphotericin B with membrane-bound sterol resulted in the formation of aqueous pores. N-acetylamphotericin B and the methyl ester of N-acetylamphotericin B, but not the smaller ring compounds, filipin, rimocidin, and PA-166, produced comparable permeability changes in identical membranes, and amphotericin B and its derivatives produced similar changes in the properties of membranes formed from phospholipid-free sterol solutions. However, amphotericin B did not affect ionic selectivity or water and nonelectrolyte permeability in membranes formed from solutions containing phospholipids and no added cholesterol, or when cholesterol was replaced by either cholesterol palmitate, dihydrotachysterol, epicholesterol, or Delta5-cholesten-3-one. Phospholipid-free sterol membranes exposed to amphotericin B or its derivatives were anion-selective, but the degree of Cl(-) selectivity varied among the compounds, and with the aqueous pH. The data are discussed with regard to, first, the nature of the polyene-sterol interactions which result in pore formation, and second, the functional groups on amphotericin B responsible for membrane anion selectivity.

  15. Sterol composition of marine algae from Karachi coast of Arabian Sea

    OpenAIRE

    Ahmad, V.U.; Perveen, S; Shaiq Ali, M.; Uddin, S; Rehman, A.; Shameel, M.

    1992-01-01

    During the course of chemical investigation of marine algae collected from Karachi coast of Arabian Sea, five sterols named as sarangosterol(1), 23-methyl cholesta-5, 25-dien-3ß-ol(2) from Endarachne binghamiae (brown alga), sargasterol(3) from Dictyota indica (brown alga), cholesterol(4) from Laurencia obtusa (red alga) and clerosterol(5) from Codium iyengarii (green alga) have been isolated. Their structures were elucidated with the help of spectroscopic means.

  16. Biosynthesis of sterols and triterpenes in cell suspension cultures of Uncaria tomentosa.

    Science.gov (United States)

    Flores-Sánchez, Isvett J; Ortega-López, Jaime; del Carmen Montes-Horcasitas, María; Ramos-Valdivia, Ana C

    2002-12-01

    Pectin administered to Uncaria tomentosa cell suspension cultures, was found to increase the production of triterpene acids (ursolic and oleanolic acid), however, neither growth nor sterol accumulation were affected. Cell cultures showed that pectin treatment caused a rapid threefold increase in the activities of enzymes involved in the biosynthesis of C(5) and C(30 )isoprenoid, such as isopentenyl diphosphate isomerase and squalene synthase. The activity of a farnesyl diphosphatase, which could divert the flux of farnesyl diphosphate to farnesol, was two times lower in elicited than in control cells. Elicited cells also transformed more rapidly a higher percentage of [5-(3)H]mevalonic acid into triterpene acids. Interestingly, addition of terbinafine, an inhibitor of squalene epoxidase, to elicited cell cultures inhibited sterol accumulation while triterpene production was not inhibited. These results suggest that in U. tomentosa cells, both the previously mentioned enzymes and those involved in squalene 2,3-oxide formation play an important regulatory role in the biosynthesis of sterols and triterpenes.

  17. Fluorinated Sterols Are Suicide Inhibitors of Ergosterol Biosynthesis and Growth in Trypanosoma brucei.

    Science.gov (United States)

    Leaver, David J; Patkar, Presheet; Singha, Ujjal K; Miller, Matthew B; Haubrich, Brad A; Chaudhuri, Minu; Nes, W David

    2015-10-22

    Trypanosoma brucei, the causal agent for sleeping sickness, depends on ergosterol for growth. Here, we describe the effects of a mechanism-based inhibitor, 26-fluorolanosterol (26FL), which converts in vivo to a fluorinated substrate of the sterol C24-methyltransferase essential for sterol methylation and function of ergosterol, and missing from the human host. 26FL showed potent inhibition of ergosterol biosynthesis and growth of procyclic and bloodstream forms while having no effect on cholesterol biosynthesis or growth of human epithelial kidney cells. During exposure of cloned TbSMT to 26-fluorocholesta-5,7,24-trienol, the enzyme is gradually killed as a consequence of the covalent binding of the intermediate C25 cation to the active site (kcat/kinact = 0.26 min(-1)/0.24 min(-1); partition ratio of 1.08), whereas 26FL is non-productively bound. These results demonstrate that poisoning of ergosterol biosynthesis by a 26-fluorinated Δ(24)-sterol is a promising strategy for developing a new treatment for trypanosomiasis.

  18. A comprehensive method for extraction and quantitative analysis of sterols and secosteroids from human plasma.

    Science.gov (United States)

    McDonald, Jeffrey G; Smith, Daniel D; Stiles, Ashlee R; Russell, David W

    2012-07-01

    We describe the development of a method for the extraction and analysis of 62 sterols, oxysterols, and secosteroids from human plasma using a combination of HPLC-MS and GC-MS. Deuterated standards are added to 200 μl of human plasma. Bulk lipids are extracted with methanol:dichloromethane, the sample is hydrolyzed using a novel procedure, and sterols and secosteroids are isolated using solid-phase extraction (SPE). Compounds are resolved on C₁₈ core-shell HPLC columns and by GC. Sterols and oxysterols are measured using triple quadrupole mass spectrometers, and lathosterol is measured using GC-MS. Detection for each compound measured by HPLC-MS was ∪ 1 ng/ml of plasma. Extraction efficiency was between 85 and 110%; day-to-day variability showed a relative standard error of <10%. Numerous oxysterols were detected, including the side chain oxysterols 22-, 24-, 25-, and 27-hydroxycholesterol, as well as ring-structure oxysterols 7α- and 4β-hydroxycholesterol. Intermediates from the cholesterol biosynthetic pathway were also detected, including zymosterol, desmosterol, and lanosterol. This method also allowed the quantification of six secosteroids, including the 25-hydroxylated species of vitamins D₂ and D₃. Application of this method to plasma samples revealed that at least 50 samples could be extracted in a routine day.

  19. Lanosterol metabolism and sterol regulatory element binding protein (SREBP) expression in male germ cell maturation.

    Science.gov (United States)

    Fon Tacer, Klementina; Kalanj-Bognar, Svjetlana; Waterman, Michael R; Rozman, Damjana

    2003-06-01

    Expression of genes involved in cholesterol biosynthesis in male germ cells is insensitive to the negative cholesterol feedback regulation, in contrast to cholesterol level-sensitive/sterol regulatory element binding protein (SREBP)-dependent gene regulation in somatic cells. The role of sterol regulatory element binding proteins in spermatogenic cells was an enigma until recently, when a soluble, 55kDa cholesterol-insensitive form of SREBP2 (SREBP2gc) was discovered [Mol. Cell. Endocrinol. 22 (2002) 8478], being translated from a germ cell-specific SREBP2 mRNA. Our RT-PCR results also show that SREBP2 as well as SREBP1c mRNAs are detectable in prepubertal and postpubertal male germ cells while SREBP1a is not detected. Surprisingly, three SREBP2 immunoreactive proteins (72, 63 and 55kDa), that are not present in mouse liver nuclei, reside in testis nuclei of prepubertal and adult mice. The 55kDa protein is likely SREBP2gc, the other two isoforms are novel. HPLC measurements in liver and testes of fasted prepubertal and postpubertal mice showed no significant difference in cholesterol level. However, FF-MAS and lanosterol/testis-meiosis activating sterol (T-MAS) intermediates that are detectable mainly in testes, increase in fasted postpubertal mice which coincides well with the elevated level of 68kDa SREBP2. Similar to SREBP2gc, the two novel SREBP2 immunoreactive proteins seem to be insensitive to the level of cholesterol.

  20. Mitochondrial function and regulation of macrophage sterol metabolism and inflammatory responses

    Institute of Scientific and Technical Information of China (English)

    Annette; Graham; Anne-Marie; Allen

    2015-01-01

    The aim of this review is to explore the role of mitochondria in regulating macrophage sterol homeostasis and inflammatory responses within the aetiology of atherosclerosis.Macrophage generation of oxysterol activators of liver X receptors(LXRs),via sterol 27-hydroxylase,is regulated by the rate of flux of cholesterolto the inner mitochondrial membrane,via a complex of cholesterol trafficking proteins.Oxysterols are key signalling molecules,regulating the transcriptional activity of LXRs which coordinate macrophage sterol metabolism and cytokine production,key features influencing the impact of these cells within atherosclerotic lesions.The precise identity of the complex of proteins mediating mitochondrial cholesterol trafficking in macrophages remains a matter of debate,but may include steroidogenic acute regulatory protein and translocator protein.There is clear evidence that targeting either of these proteins enhances removal of cholesterol via LXRα-dependent induction of ATP binding cassette transporters(ABCA1,ABCG1) and limits the production of inflammatory cytokines; interventions which influence mitochondrial structure and bioenergetics also impact on removal of cholesterol from macrophages.Thus,molecules which can sustain or improve mitochondrial structure,the function of the electron transport chain,or increase the activity of components of the protein complex involved in cholesterol transfer,may therefore have utility in limiting or regressing atheroma development,reducing the incidence of coronary heart disease and myocardial infarction.

  1. Divergent changes in serum sterols during a strict uncooked vegan diet in patients with rheumatoid arthritis.

    Science.gov (United States)

    Agren, J J; Tvrzicka, E; Nenonen, M T; Helve, T; Hänninen, O

    2001-02-01

    The effects of a strict uncooked vegan diet on serum lipid and sterol concentrations were studied in patients with rheumatoid arthritis. The subjects were randomized into a vegan diet group (n 16), who consumed a vegan diet for 2-3 months, or into a control group (n 13), who continued their usual omnivorous diets. Serum total and LDL-cholesterol and -phospholipid concentrations were significantly decreased by the vegan diet. The levels of serum cholestanol and lathosterol also decreased, but serum cholestanol:total cholesterol and lathosterol:total cholesterol did not change. The effect of a vegan diet on serum plant sterols was divergent as the concentration of campesterol decreased while that of sitosterol increased. This effect resulted in a significantly greater sitosterol:campesterol value in the vegan diet group than in the control group (1.48 (SD 0.39) v. 0.72 (SD 0.14); P vegan diet changes the relative absorption rates of these sterols and/or their biliary clearance.

  2. Role of membrane sterols and cortical microtubules in gravity resistance in plants

    Science.gov (United States)

    Hoson, T.; Koizumi, T.; Matsumoto, S.; Kumasaki, S.; Soga, K.; Wakabayashi, K.; Sakaki, T.

    Resistance to the gravitational force is a principal graviresponse in plants comparable to gravitropism Nevertheless only limited information has been obtained for this graviresponse We have examined mechanisms of signal perception transformation and transduction of the perceived signal and response to the transduced signal in gravity resistance using hypergravity conditions produced by centrifugation In Arabidopsis hypocotyls hypergravity treatment greatly increased the expression level of 3-hydroxy-3-methylglutaryl-Coenzyme A reductase HMGR which catalyzes a reaction producing mevalonic acid a key precursor of terpenoids such as membrane sterols Geranyl diphosphate synthase gene was also up-regulated by hypergravity whereas the expression of other genes involved in membrane lipid metabolism was not influenced Hypergravity caused an increase in sterol content in azuki bean epicotyls but not in phospholipid glycolipid or fatty acid content Also hypergravity did not influence fatty acid composition in any lipid class Thus the effect of hypergravity on membrane lipid metabolism was specific for sterol synthesis On the other hand alpha- and beta-tubulin genes were up-regulated by hypergravity treatment in Arabidopsis hypocotyls Hypergravity also induced reorientation of cortical microtubules in azuki epicotyls the percentage of epidermal cells with transverse microtubles was decreased whereas that with longitudinal microtubules was increased Inhibitors of HMGR action and microtubule-disrupting agents completely prevented the gravity resistance

  3. Correlation of neomycin, faecal neutral and acid sterols with colon carcinogenesis in rats.

    Science.gov (United States)

    Panda, S K; Chattoraj, S C; Broitman, S A

    1999-06-01

    High fat diets have been implicated in incidence of colon cancer both in epidemiological and animal studies. Present investigation deals with the incidence, location and numbers of large and small bowel tumours induced by 1,2-dimethyl hydrazine (DMH) in rats fed high fat diets and neomycin. Neomycin was used to modify the faecal sterol metabolism and the relationship of the high fat diet and faecal neutral and acid sterols to the large bowel tumorigenesis was evaluated. DMH administered rats were fed with (a) 20% safflower oil; (b) 20% safflower oil and neomycin; (c) 20% safflower oil, cholesterol and cholic acid; and (d) 20% safflower oil, cholesterol, cholic acid and neomycin. Neomycin was found to be associated with both increase and decrease of tumour numbers. The faecal sterols lithocholic and deoxycholic acids were found to have no participation, while cholesterol and cholic acid were found to decrease with increase in tumour numbers. However, faecal coprostanol has been found to have a significant positive correlation with tumorigenesis in all dietary groups. Therefore coprostanol might possibly be associated with colon carcinogenesis in DMH-fed rats and cholesterol metabolism in gut appears to be related to the development of tumours.

  4. Fatty acids, sterols, and antioxidant activity in minimally processed avocados during refrigerated storage.

    Science.gov (United States)

    Plaza, Lucía; Sánchez-Moreno, Concepción; de Pascual-Teresa, Sonia; de Ancos, Begoña; Cano, M Pilar

    2009-04-22

    Avocado ( Persea americana Mill.) is a good source of bioactive compounds such as monounsaturated fatty acids and sterols. The impact of minimal processing on its health-promoting attributes was investigated. Avocados cut into slices or halves were packaged in plastic bags under nitrogen, air, or vacuum and stored at 8 degrees C for 13 days. The stabilities of fatty acids and sterols as well as the effect on antioxidant activity were evaluated. The main fatty acid identified and quantified in avocado was oleic acid (about 57% of total content), whereas beta-sitosterol was found to be the major sterol (about 89% of total content). In general, after refrigerated storage, a significant decrease in fatty acid content was observed. Vacuum/halves and air/slices were the samples that maintained better this content. With regard to phytosterols, there were no significant changes during storage. Antioxidant activity showed a slight positive correlation against stearic acid content. At the end of refrigerated storage, a significant increase in antiradical efficiency (AE) was found for vacuum samples. AE values were quite similar among treatments. Hence, minimal processing can be a useful tool to preserve health-related properties of avocado fruit.

  5. Novel approach to determining the absolute configurations at the C3-positions of various types of sterols based on an induced circular dichroism.

    Science.gov (United States)

    Fujiwara, Toshio; Taniguchi, Yuka; Katsumoto, Yukiteru; Tanaka, Takeyuki; Ozeki, Minoru; Iwasaki, Hiroki; Node, Manabu; Yamashita, Masayuki; Hosoi, Shinzo

    2012-10-01

    Circular dichroism (CD) spectra of the 2,2'-binaphthyl ester derived from Δ(5)-sterols showed not bisignate CD but diagnostic CD bands at around 210 and 240 nm. These bands might be attributable to an interaction between an olefinic chromophore and a binaphthyl one. Various types of unsaturated sterols were thus derivatized followed by complete hydrogenation, to give saturated sterols. As a result, CD spectra of the binaphthyl derivatives of the saturated sterols showed bisignate curves centered at 240 nm (3S(β): positive chirality; 3R(α): negative one). This suggested a straightforward and practical method for discriminating the absolute stereogenic center at the C-3 positions of sterols based on an induced CD. This finding should contribute significantly to the analysis of metabolites of various types of sterols. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Changes in the sterol compositions of milk thistle oil (Silybium marianum L. during seed maturation

    Directory of Open Access Journals (Sweden)

    Harrabi, S.

    2016-03-01

    Full Text Available In this study, the total lipid content and sterol compositions were determined during the development of milk thistle seeds. The oil content increased to a maximum value of 36±1.7% and then declined to reach a value of 30.5±0.9% at full maturity. The sterol content of milk thistle seeds was affected by the ripening degree of the seeds. At the early stages of seed maturation, Δ7-stigmastenol was the most abundant sterol followed by β-sitosterol. However, at full maturity, β-sitosterol was the most predominant sterol (46.50±0.8%. As the seed developed, campesterol and stigmasterol amounts increased, while Δ7-avenasterol content decreased. It can be concluded that milk thistle seed oil has a characteristic sterol pattern comparable to the ones elucidated for olive oil and corn oil. The extracted oil from milk thistle seeds is rich in phytosterols and could be used in food preparation and human nutrition.En este estudio se determinaron la composición de lípidos totales y esteroles durante el desarrollo de semillas de cardo mariano. El contenido de aceite incrementó a un valor máximo de 36±1,7% y posteriormente disminuyó hasta alcanzar un valor de 30,5±0,9% cuando la maduración fue completa. El contenido de esteroles de las semillas de cardo mariano se ve afectado por el grado de maduración de las semillas. En las primeras etapas de la maduración de las semillas el Δ7-estigmastenol fué el esterol más abundante, seguido de β-sitosterol. Sin embargo en plena madurez, β-sitosterol fue el esterol predominante (46,50±0,8%. A medida que las semillas se desarrollan las cantidades de campesterol y estigmasterol aumentan, mientras que el contenido Δ7-avenasterol disminuye. Se puede concluir que el aceite de semillas de cardo mariano tiene un patrón característico de esteroles en comparación con lo especificado para los aceites de oliva y de maíz. El aceite extraído de las semillas del cardo mariano es rica en fitoesteroles y podr

  7. Final report of the amended safety assessment of PEG-5, -10, -16, -25, -30, and -40 soy sterol.

    Science.gov (United States)

    2004-01-01

    PEGs Soy Sterol are polyethylene glycol (PEG) derivatives of soybean oil sterols used in a variety of cosmetic formulations as surfactants and emulsifying agents, skin-conditioning agents, and cleansing and solubilizing agents. When the safety of these ingredients were first reviewed, the available data were insufficient to support safety. New data have since been received and the safety of these ingredients in cosmetics has been substantiated. Current concentration of use ranges from a low of 0.05% in makeup preparations to 2% in moisturizers and several other products. PEGs Soy Sterol are produced by the reaction of the soy sterol hydroxyl with ethylene oxide. In general, ethoxylated fatty acids can contain 1,4-dioxane as a byproduct of ethoxylation. The soy sterols include campesterol, stigmasterol, and beta-sitosterol. The distribution of sterols found in oils derived from common plants is similar, with beta-sitosterol comprising a major component. Impurities include sterol hydrocarbons and cholesterol (4% to 6%) and triterpine alcohols, keto-steroids, and other steroid-like substances (4% to 6%). No pesticide residues were detected. PEGS: Because PEGs are an underlying structure in PEGs Soy Sterols, the previous assessment of PEGs was considered. It is generally recognized that the PEG monomer, ethylene glycol, and certain of its monoalkyl ethers are reproductive and developmental toxins. Given the methods of manufacture of PEGs Soy Sterol, there is no likelihood of ethylene glycol or its alkyl ethers being present. Also, the soybean oil sterol ethers in this ingredient are chemically different from the ethylene glycol alkyl ethers of concern. PEGs are not carcinogenic, although sensitization and nephrotoxicity were observed in burn patients treated with a PEG-based cream. No evidence of systemic toxicity or sensitization was found in studies with intact skin. Plant Phytosterols: Intestinal absorption of ingested plant phytosterols is on the order of 5%, with

  8. A highly specific and sensitive quantification analysis of the sterols in silkworm larvae by high performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Igarashi, Fumihiko; Hikiba, Juri; Ogihara, Mari H; Nakaoka, Takayoshi; Suzuki, Minoru; Kataoka, Hiroshi

    2011-12-15

    The biochemical quantification of sterols in insects has been difficult because only small amounts of tissues can be obtained from insect bodies and because sterol metabolites are structurally related. We have developed a highly specific and sensitive quantitative method for determining of the concentrations of seven sterols-7-dehydrocholesterol, desmosterol, cholesterol, ergosterol, campesterol, stigmasterol, and β-sitosterol-using a high performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (HPLC/APCI-MS/MS). The sterols were extracted from silkworm larval tissues using the Bligh and Dyer method and were analyzed using HPLC/APCI-MS/MS with selected reaction monitoring, using cholesterol-3,4-(13)C(2) as an internal standard. The detection limits of the method were between 12.1 and 259 fmol. The major sterol in most silkworm larval tissues was cholesterol, whereas only small quantities of the dietary sterols were detected. Thus, a simple, sensitive, and specific method was successfully developed for the quantification of the sterol concentrations in each tissue of an individual silkworm larva. This method will be a useful tool for investigating to molecular basis of sterol physiology in insects, facilitating the quantification of femtomole quantities of sterols in biological samples. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. Sterol composition of virgin olive oil of forty-three olive cultivars from the World Collection Olive Germplasm Bank of Cordoba.

    Science.gov (United States)

    Kyçyk, Onejda; Aguilera, Maria Paz; Gaforio, José Juan; Jiménez, Antonio; Beltrán, Gabriel

    2016-09-01

    In olive oil, sterols constitute the majority of the unsaponifiable fraction. In recent years there has been increased interest in the sterols of olive oil for their health benefits and their importance to virgin olive oil (VOO) quality regulation. Forty-three olive (Olea europaea L.) cultivars from the World Olive Germplasm Bank, IFAPA Centro 'Alameda de Obispo', Cordoba, Spain were studied for their oil sterol composition and total content. The main sterols found in olive oil were β-sitosterol, Δ(5) -avenasterol, campesterol and stigmasterol, most of them showing high variability. Most cultivars showed total sterol contents within the limits established by EU regulations, although 28% of VOOs analysed were outside the limits established for total content and/or for individual sterols. Over the group of cultivars, total sterol contents ranged from 855 to 2185 mg kg(-1) . The high variability observed was due to the genetic component, since other agronomic and technological factors were similar. Because of the high variability, the sterol fraction can be considered as a useful tool to characterize and discriminate monovarietal VOOs. The results can be useful for nutritionists for VOO inclusion in nutrition studies. Furthermore, the variability observed can be applied in olive breeding projects to select the parents of new olive cultivars with an improved sterol fraction. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  10. Tritium Suicide Selection Identifies Proteins Involved in the Uptake and Intracellular Transport of Sterols in Saccharomyces cerevisiae▿

    Science.gov (United States)

    Sullivan, David P.; Georgiev, Alexander; Menon, Anant K.

    2009-01-01

    Sterol transport between the plasma membrane (PM) and the endoplasmic reticulum (ER) occurs by a nonvesicular mechanism that is poorly understood. To identify proteins required for this process, we isolated Saccharomyces cerevisiae mutants with defects in sterol transport. We used Upc2-1 cells that have the ability to take up sterols under aerobic conditions and exploited the observation that intracellular accumulation of exogenously supplied [3H]cholesterol in the form of [3H]cholesteryl ester requires an intact PM-ER sterol transport pathway. Upc2-1 cells were mutagenized using a transposon library, incubated with [3H]cholesterol, and subjected to tritium suicide selection to isolate mutants with a decreased ability to accumulate [3H]cholesterol. Many of the mutants had defects in the expression and trafficking of Aus1 and Pdr11, PM-localized ABC transporters that are required for sterol uptake. Through characterization of one of the mutants, a new role was uncovered for the transcription factor Mot3 in controlling expression of Aus1 and Pdr11. A number of mutants had transposon insertions in the uncharacterized Ydr051c gene, which we now refer to as DET1 (decreased ergosterol transport). These mutants expressed Aus1 and Pdr11 normally but were severely defective in the ability to accumulate exogenously supplied cholesterol. The transport of newly synthesized sterols from the ER to the PM was also defective in det1Δ cells. These data indicate that the cytoplasmic protein encoded by DET1 is involved in intracellular sterol transport. PMID:19060182

  11. Acyl-CoA:cholesterol acyltransferases (ACATs/SOATs): Enzymes with multiple sterols as substrates and as activators.

    Science.gov (United States)

    Rogers, Maximillian A; Liu, Jay; Song, Bao-Liang; Li, Bo-Liang; Chang, Catherine C Y; Chang, Ta-Yuan

    2015-07-01

    Cholesterol is essential to the growth and viability of cells. The metabolites of cholesterol include: steroids, oxysterols, and bile acids, all of which play important physiological functions. Cholesterol and its metabolites have been implicated in the pathogenesis of multiple human diseases, including: atherosclerosis, cancer, neurodegenerative diseases, and diabetes. Thus, understanding how cells maintain the homeostasis of cholesterol and its metabolites is an important area of study. Acyl-coenzyme A:cholesterol acyltransferases (ACATs, also abbreviated as SOATs) converts cholesterol to cholesteryl esters and play key roles in the regulation of cellular cholesterol homeostasis. ACATs are most unusual enzymes because (i) they metabolize diverse substrates including both sterols and certain steroids; (ii) they contain two different binding sites for steroidal molecules. In mammals, there are two ACAT genes that encode two different enzymes, ACAT1 and ACAT2. Both are allosteric enzymes that can be activated by a variety of sterols. In addition to cholesterol, other sterols that possess the 3-beta OH at C-3, including PREG, oxysterols (such as 24(S)-hydroxycholesterol and 27-hydroxycholesterol, etc.), and various plant sterols, could all be ACAT substrates. All sterols that possess the iso-octyl side chain including cholesterol, oxysterols, various plant sterols could all be activators of ACAT. PREG can only be an ACAT substrate because it lacks the iso-octyl side chain required to be an ACAT activator. The unnatural cholesterol analogs epi-cholesterol (with 3-alpha OH in steroid ring B) and ent-cholesterol (the mirror image of cholesterol) contain the iso-octyl side chain but do not have the 3-beta OH at C-3. Thus, they can only serve as activators and cannot serve as substrates. Thus, within the ACAT holoenzyme, there are site(s) that bind sterol as substrate and site(s) that bind sterol as activator; these sites are distinct from each other. These features form

  12. A liquid chromatography-tandem mass spectrometry-based method for the simultaneous determination of hydroxy sterols and bile acids.

    Science.gov (United States)

    John, Clara; Werner, Philipp; Worthmann, Anna; Wegner, Katrin; Tödter, Klaus; Scheja, Ludger; Rohn, Sascha; Heeren, Joerg; Fischer, Markus

    2014-12-01

    Recently, hydroxy sterols and bile acids have gained growing interest as they are important regulators of energy homoeostasis and inflammation. The high number of different hydroxy sterols and bile acid species requires powerful analytical tools to quantify these structurally and chemically similar analytes. Here, we introduce a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method for rapid quantification of 34 sterols (hydroxy sterols, primary, secondary bile acids as well as their taurine and glycine conjugates). Chromatographic baseline separation of isomeric hydroxy sterols and bile acids is obtained using a rugged amide embedded C18 (polar embedded) stationary phase. The current method features a simple extraction protocol validated for blood plasma, urine, gall bladder, liver, feces, and adipose tissue avoiding solid phase extraction as well as derivatization procedures. The total extraction recovery for representative analytes ranged between 58-86% in plasma, 85% in urine, 79-92% in liver, 76-98% in adipose tissue, 93-104% in feces and 62-79% in gall bladder. The validation procedure demonstrated that the calibration curves were linear over the selected concentration ranges for 97% of the analytes, with calculated coefficients of determination (R2) of greater than 0.99. A feeding study in wild type mice with a standard chow and a cholesterol-enriched Western type diet illustrated that the protocol described here provides a powerful tool to simultaneously quantify cholesterol derivatives and bile acids in metabolically active tissues and to follow the enterohepatic circulation.

  13. Diet micronutrient balance matters: How the ratio of dietary sterols/steroids affects development, growth and reproduction in two lepidopteran insects.

    Science.gov (United States)

    Jing, Xiangfeng; Grebenok, Robert J; Behmer, Spencer T

    2014-08-01

    Insects lack the ability to synthesize sterols de novo so they acquire this essential nutrient from their food. Cholesterol is the dominant sterol found in most insects, but in plant vegetative tissue it makes up only a small fraction of the total sterol profile. Instead, plants mostly contain phytosterols; plant-feeding insects generate the majority of their cholesterol by metabolizing phytosterols. However, not all phytosterols are readily converted to cholesterol, and some are even deleterious when ingested above a threshold level. In a recent study we showed that caterpillars reared on tobacco accumulating novel sterols/steroids exhibited reduced performance, even when suitable sterols were present. In the current study we examined how the dominant sterols (cholesterol and stigmasterol) and steroids (cholestanol and cholestanone) typical of the modified tobacco plants affected two insect herbivores (Heliothis virescens and Helicoverpa zea). The sterols/steroids were incorporated into synthetic diets singly, as well as in various combinations, ratios and amounts. For each insect species, a range of performance values was recorded for two generations, with the eggs from the 1st-generation adults as the source of neonates for the 2nd-generation. Performance on the novel steroids (cholestanol and cholestanone) was extremely poor compared to suitable sterols (cholesterol and stigmasterol). Additionally, performance tended to decrease as the ratio of the novel dietary steroids increased. We discuss how the balance of different dietary sterols/steroids affected our two caterpillar species, relate this back to recent studies on sterol/steroid metabolism in these two species, and consider the potential application of sterol/steroid modification in crops. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Sterols with antileishmanial activity isolated from the roots of Pentalinon andrieuxii.

    Science.gov (United States)

    Pan, Li; Lezama-Davila, Claudio M; Isaac-Marquez, Angelica P; Calomeni, Edward P; Fuchs, James R; Satoskar, Abhay R; Kinghorn, A Douglas

    2012-10-01

    A new cholesterol derivative, pentalinonsterol (cholest-4,20,24-trien-3-one, 1), and a new polyoxygenated pregnane sterol glycoside, pentalinonside (2), together with 18 known compounds, including 14 sterols (3-16), three coumarins (17-19), and a triterpene (20), were isolated from a n-hexane partition of a methanol extract of the roots of the Mexican medicinal plant Pentalinon andrieuxii. Structure elucidation of compounds 1 and 2 was accomplished by spectroscopic data interpretation. All isolates were evaluated in vitro for their antileishmanial activity. Among these compounds, 6,7-dihydroneridienone (15) was found to be the most potent principle against promastigotes of Leishmania mexicana (L. mexicana). The cholesterol analogue, pentalinonsterol (1), together with two known sterols, 24-methylcholest-4,24(28)-dien-3-one (3) and neridienone (16), also exhibited significant leishmanicidal activity in this same bioassay. Compounds 1, 3, 15, 16, cholest-4-en-3-one (4), and cholest-5,20,24-trien-3β-ol (7), showed strong antileishmanial activity against amastigotes of L. mexicana, and 4 was found to be the most potent agent with an IC(50) value of 0.03μM. All the isolates were also evaluated for their cytotoxicity in non-infected bone marrow-derived macrophages, but none of these compounds was found active towards this cell line. The intracellular parasites treated with compounds 1, 3, 4, 15, and 16 were further studied by electron microscopy; morphological abnormalities and destruction of the amastigotes were observed, as a result of treatment with these compounds. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Evidence that the intra-amoebal Legionella drancourtii acquired a sterol reductase gene from eukaryotes

    Directory of Open Access Journals (Sweden)

    Fournier Pierre-Edouard

    2009-03-01

    Full Text Available Abstract Background Free-living amoebae serve as a natural reservoir for some bacteria that have evolved into «amoeba-resistant» bacteria. Among these, some are strictly intra-amoebal, such as Candidatus "Protochlamydia amoebophila" (Candidatus "P. amoebophila", whose genomic sequence is available. We sequenced the genome of Legionella drancourtii (L. drancourtii, another recently described intra-amoebal bacterium. By comparing these two genomes with those of their closely related species, we were able to study the genetic characteristics specific to their amoebal lifestyle. Findings We identified a sterol delta-7 reductase-encoding gene common to these two bacteria and absent in their relatives. This gene encodes an enzyme which catalyses the last step of cholesterol biosynthesis in eukaryotes, and is probably functional within L. drancourtii since it is transcribed. The phylogenetic analysis of this protein suggests that it was acquired horizontally by a few bacteria from viridiplantae. This gene was also found in the Acanthamoeba polyphaga Mimivirus genome, a virus that grows in amoebae and possesses the largest viral genome known to date. Conclusion L. drancourtii acquired a sterol delta-7 reductase-encoding gene of viridiplantae origin. The most parsimonious hypothesis is that this gene was initially acquired by a Chlamydiales ancestor parasite of plants. Subsequently, its descendents transmitted this gene in amoebae to other intra-amoebal microorganisms, including L. drancourtii and Coxiella burnetii. The role of the sterol delta-7 reductase in prokaryotes is as yet unknown but we speculate that it is involved in host cholesterol parasitism.

  16. Phytoestrogens and sterols in waters with cyanobacterial blooms - Analytical methods and estrogenic potencies.

    Science.gov (United States)

    Procházková, Tereza; Sychrová, Eliška; Javůrková, Barbora; Večerková, Jaroslava; Kohoutek, Jiří; Lepšová-Skácelová, Olga; Bláha, Luděk; Hilscherová, Klára

    2017-03-01

    Compounds with estrogenic potencies and their adverse effects in surface waters have received much attention. Both anthropogenic and natural compounds contribute to overall estrogenic activity in freshwaters. Recently, estrogenic potencies were also found to be associated with cyanobacteria and their blooms in surface waters. The present study developed and compared the solid phase extraction and LC-MS/MS analytical approaches for determination of phytoestrogens (8 flavonoids - biochanin A, coumestrol, daidzein, equol, formononetin, genistein, naringenin, apigenin - and 5 sterols - ergosterol, β-sitosterol, stigmasterol, campesterol, brassicasterol) and cholesterol in water. The method was used for analyses of samples collected in stagnant water bodies dominated by different cyanobacterial species. Concentrations of individual flavonoids ranged from below the limit of detection to 3.58 ng/L. Sterols were present in higher amounts up to 2.25 μg/L. Biological potencies of these phytoestrogens in vitro were characterized using the hERα-HeLa-9903 cell line. The relative estrogenic potencies (compared to model estrogen - 17β-estradiol) of flavonoids ranged from 2.25E-05 to 1.26E-03 with coumestrol being the most potent. None of the sterols elicited estrogenic response in the used bioassay. Estrogenic activity was detected in collected field water samples (maximum effect corresponding to 2.07 ng/L of 17β-estradiol equivalents, transcriptional assay). At maximum phytoestrogens accounted for only 1.56 pg/L of 17β-estradiol equivalents, contributing maximally 8.5% of the total estrogenicity of the water samples. Other compounds therefore, most likely of anthropogenic origin such as steroid estrogens, are probably the major drivers of total estrogenic effects in these surface waters.

  17. Epigenetic modifier-induced biosynthesis of novel acetylenic sterols from Cladosporium colocasiae.

    Science.gov (United States)

    Liu, Dong-Ze; Liang, Bo-Wen; Li, Xiao-Fei; Yu, Zhi-Yuan

    2014-09-01

    The addition of an HDAC inhibitor, suberoylanilide hydroxamic acid (SBHA), to the culture medium of Cladosporium colocasiae, dramatically altered its metabolic profiles. Analysis of the culture broth extract led to the isolation of two new acetylenic sterols (1-2). The isolated compounds were further evaluated for their cytotoxic and antibacterial activities. Compound 1 showed activity against Bacillus subtilis, affording a zone of inhibition of 12mm at 100μg/disk. However, none of them showed noticeable growth inhibitory effects. Copyright © 2014. Published by Elsevier Inc.

  18. Click chemistry decoration of amino sterols as promising strategy to developed new leishmanicidal drugs.

    Science.gov (United States)

    Porta, Exequiel O J; Carvalho, Paulo B; Avery, Mitchell A; Tekwani, Babu L; Labadie, Guillermo R

    2014-01-01

    A series of 1,2,3-triazolylsterols was prepared from pregnenolone through reductive amination and copper(I)-catalyzed azide-alkyne cycloaddition (click chemistry). The newly generated stereocenter of the key propargylamino intermediate provided a mixture of diastereomers which were separated chromatographically, and the configuration of the R isomer was determined by X-ray crystallography. Ten triazolyl sterols were prepared, and the products and intermediates were screened in vitro against different parasites, with some compounds presenting IC50 values in the low micromolar range against Leishmania donovani. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Can Sterol Carrie Protein-2 function as a solubility tag in E.coli?

    OpenAIRE

    Lundén, Amanda

    2016-01-01

    Expressing foreign proteins in E.coli is a major challenge because they often tend to develop into unsolvable and inactive proteins. They aggregate into so called  inclusion bodies which prevent expression of the protein. This problem might be avoided by fusing the gene of the foreign protein with a soluble protein called solubility tags, which  function is to enhance the solubility of the foreign protein. This report investigates whether Sterol Carrier Protein-2 (SCP-2) could function as a s...

  20. Human Sterol Regulatory Element-Binding Protein 1a Contributes Significantly to Hepatic Lipogenic Gene Expression

    OpenAIRE

    Andreas Bitter; Nüssler, Andreas K.; Thasler, Wolfgang E.; Kathrin Klein; Zanger, Ulrich M.; Matthias Schwab; Oliver Burk

    2015-01-01

    Background/Aims: Sterol regulatory element-binding protein (SREBP) 1, the master regulator of lipogenesis, was shown to be associated with non-alcoholic fatty liver disease, which is attributed to its major isoform SREBP1c. Based on studies in mice, the minor isoform SREBP1a is regarded as negligible for hepatic lipogenesis. This study aims to elucidate the expression and functional role of SREBP1a in human liver. Methods: mRNA expression of both isoforms was quantified in cohorts of human li...

  1. Moving out: from sterol transport to drug resistance - the ABCG subfamily of efflux pumps.

    Science.gov (United States)

    Moitra, Karobi; Silverton, Latoya; Limpert, Katy; Im, Kate; Dean, Michael

    2011-01-01

    The ATP binding cassette (ABC) proteins are typically ATP-driven transmembrane pumps that have been evolutionarily conserved from bacteria to humans. In humans these transporters are subdivided into seven subfamilies, ranging from A to G. The ABCG subfamily of transporters is the primary focus of this review. This subfamily of proteins has been conserved throughout evolution and plays a central role in several cellular processes, such as sterol homeostasis and multidrug resistance. Functional polymorphisms/mutations in some of these G-subfamily transporters have clinical consequences in humans.

  2. Identification of hopanoid, sterol, and tetrahymanol production in the aerobic methanotroph Methylomicrobium alcaliphilum 20Z

    Science.gov (United States)

    Welander, P. V.; Summons, R. E.

    2013-12-01

    Correlating the occurrence of molecular biosignatures preserved in the rock record with specific microbial taxa is a compelling strategy for studying microbial life in the context of the Earth's distant past. Polycyclic triterpenoids, including the hopanes and steranes, comprise classes of biomarkers that are readily detected in a variety of ancient sediments and are clearly recognized as the diagenetic products of modern day bacterial hopanoids and eukaryotic sterols. Thus, based on the distribution of these lipids in extant microbes, the occurrence of their diagenetic products in the rock record is often utilized as evidence for the existence of specific bacterial and eukaryotic taxa in ancient ecosystems. However, questions have arisen about our understanding of the taxonomic distribution of many of these molecular biomarkers in extant microbes. This is prompting reassessments of the use of polycyclic triterpenoids as geological proxies for microbial taxa, especially in the light of the poorly defined issue of microbial diversity. Recently, significant effort has been put forth to better understand the biosynthesis, function, and regulation of these lipid molecules in a variety of modern organisms so that a more informed interpretation of their occurrence in the rock record can be reached. Here we report the unprecedented production of three different classes of polycyclic triterpenoid biomarker lipids in one bacterium. Methylomicrobium alcaliphilum 20Z, a member of the Gammaproteobacteria, is a halotolerant alkaliphilic aerobic methanotroph previously isolated from a moderately saline soda lake in Tuva (Central Asia). In this study, M. alcaliphilum is shown to produce C-3 methylated and unmethylated aminohopanoids commonly associated with other mesophilic aerobic methanotrophs. In addition, this organism is also able to produce 4,4-dimethyl sterols and surprisingly, the gammacerane triterpenoid tetrahymanol. Previously, tetrahymanol production has only been

  3. Recombinant sterol esterase from Ophiostoma piceae: an improved biocatalyst expressed in Pichia pastoris

    Directory of Open Access Journals (Sweden)

    Cedillo Víctor

    2012-06-01

    Full Text Available Abstract Background The ascomycete Ophiostoma piceae produces a sterol esterase (OPE with high affinity towards p-nitrophenol, glycerol and sterol esters. Its hydrolytic activity on natural mixtures of triglycerides and sterol esters has been proposed for pitch biocontrol in paper industry since these compounds produce important economic losses during paper pulp manufacture. Results Recently, this enzyme has been heterologously expressed in the methylotrophic yeast Pichia pastoris, and the hydrolytic activity of the recombinant protein (OPE* studied. After the initial screening of different clones expressing the enzyme, only one was selected for showing the highest production rate. Different culture conditions were tested to improve the expression of the recombinant enzyme. Complex media were better than minimal media for production, but in any case the levels of enzymatic activity were higher (7-fold in the best case than those obtained from O. piceae. The purified enzyme had a molecular mass of 76 kDa, higher than that reported for the native enzyme under SDS-PAGE (60 kDa. Steady-state kinetic characterization of the recombinant protein showed improved catalytic efficiency for this enzyme as compared to the native one, for all the assayed substrates (p-nitrophenol, glycerol, and cholesterol esters. Different causes for this were studied, as the increased glycosylation degree of the recombinant enzyme, their secondary structures or the oxidation of methionine residues. However, none of these could explain the improvements found in the recombinant protein. N-terminal sequencing of OPE* showed that two populations of this enzyme were expressed, having either 6 or 8 amino acid residues more than the native one. This fact affected the aggregation behaviour of the recombinant protein, as was corroborated by analytical ultracentrifugation, thus improving the catalytic efficiency of this enzyme. Conclusion P. pastoris resulted to be an optimum

  4. Transcriptional integration of metabolism by the nuclear sterol-activated receptors LXR and FXR.

    Science.gov (United States)

    Calkin, Anna C; Tontonoz, Peter

    2012-03-14

    Nuclear receptors are integrators of hormonal and nutritional signals, mediating changes to metabolic pathways within the body. Given that modulation of lipid and glucose metabolism has been linked to diseases including type 2 diabetes, obesity and atherosclerosis, a greater understanding of pathways that regulate metabolism in physiology and disease is crucial. The liver X receptors (LXRs) and the farnesoid X receptors (FXRs) are activated by oxysterols and bile acids, respectively. Mounting evidence indicates that these nuclear receptors have essential roles, not only in the regulation of cholesterol and bile acid metabolism but also in the integration of sterol, fatty acid and glucose metabolism.

  5. Sterols and triterpenoids as potential anti-inflammatories: Molecular docking studies for binding to some enzymes involved in inflammatory pathways.

    Science.gov (United States)

    Loza-Mejía, Marco A; Salazar, Juan Rodrigo

    2015-11-01

    Triterpenes and sterols are good candidates for the development of anti-inflammatory drugs and use in chemoprevention or chemotherapy of cancer via the interaction with therapeutic targets related to inflammation, such as COX-1 and -2; LOX-5; MPO, PLA2 and i-NOS. In this study, we use molecular docking to evaluate the potential binding of a database of selected sterol and triterpenoid compounds with several skeletons against enzymes related to inflammation to propose structural requirements beneficial for anti-inflammatory activity that can be used for the design of more potent and selective anti-inflammatory and antitumor drugs. Our results suggest that the substitution pattern is important and that there is an important relationship between the class of sterol or triterpenoid skeleton and enzyme binding.

  6. Effect of Transition Metal Ions on the B Ring Oxidation of Sterols and their Kinetics in Oil-in-Water Emulsions

    Science.gov (United States)

    Lu, Baiyi; Hu, Yinzhou; Huang, Weisu; Wang, Mengmeng; Jiang, Yuan; Lou, Tiantian

    2016-06-01

    This study investigated the effect of metal ions on the oxidation of sterols and their kinetics in oil-in-water emulsions. Sterol substrates were added with different metal ions (Cu2+, Fe2+, Mn2+, Zn2+, Na+, and Mg2+) of five concentrations and investigated after 2 h of heating at 90 °C. The substrates added with Fe2+ and Cu2+ were heated continuously to evaluate the kinetics of four sterols and their corresponding sterol oxidation products (SOPs). Sterol oxidation increased as the metal ion concentration increased and the heating time was prolonged. The capability of the metal ions oxidizing sterols ranked as followed: Fe2+ > Cu2+ > Mn2+ > Zn2+ > Mg2+ ≈ Na+. 7-Ketosterol, 7β/7α-Hydroxysterol, 5β,6β/5α,6α-Epoxysterol, and Triols were the main oxides on the B ring, whereas 6β-Hydroxysterol was not or only slightly influenced. The acceleration of sterol degradation induced by Fe2+ and Cu2+, as well as the formation of oxidation products, followed first-order formation/elimination kinetics. The acceleration effect may be partly ascribed to the increase in elimination rate constant and formation rate constant. Transition metal ions can significantly induce sterol oxidation, which reduces food nutritional quality and triggers the formation of undesirable compounds, such as SOPs.

  7. GC-MS method for determining faecal sterols as biomarkers of human and pastoral animal presence in freshwater sediments.

    Science.gov (United States)

    Battistel, Dario; Piazza, Rossano; Argiriadis, Elena; Marchiori, Enrico; Radaelli, Marta; Barbante, Carlo

    2015-11-01

    In order to determine sterols and stanols in freshwater sediments to reconstruct the past presence of humans and pastoral animals, we developed an analytical method based on pressurised liquid extraction (PLE), clean-up performed using solid phase extraction (SPE) and sterol determination using gas chromatography-mass spectrometry (GC-MS) analysis. PLE extraction conditions were optimised using dichloromethane (DCM) and DCM/methanol mixtures. Clean-up was performed with 2 g silica SPE cartridges, and the concentrated extracts were eluted with 70 mL DCM. Extraction yield was evaluated using an in-house reference material spiked with (13)C-labelled cholesterol and aged for 10 days. In comparison with pre-extraction, where the sediment is extracted and then spiked with a known analyte concentration, this approach preserves the original composition of the sediment. DCM and DCM/methanol mixtures resulted in high extraction yields ranging from 86 to 92 % with good reproducibility (relative standard deviation (RSD) 5-8 %). PLE extraction yields obtained with DCM as the extracting solvent were about 1.5 times higher than extractions using an ultrasonic bath. The solvent extraction mixture and matrix composition strongly affected the solvent extraction composition where higher overall recoveries (70-80 %) for each compound were obtained with DCM. The extraction mixture and matrix composition also affected the analyte concentrations, resulting in a method precision ranging from 1 to 18 %. Diatomaceous earth spiked with 10 to 100 ng of sterols, and environmental samples fortified with suitable amounts of sterols provided apparent recovery values ranging from 90 to 110 %. We applied the method to environmental samples both close to and upstream from sewage discharge zones, resulting in substantially higher faecal sterol (FeSt) concentrations near the sewage. In addition, we also applied the method to a 37-cm freshwater sediment core in order to evaluate its applicability for

  8. Substrate Preferences and Catalytic Parameters Determined by Structural Characteristics of Sterol 14[alpha]-Demethylase (CYP51) from Leishmania infantum

    Energy Technology Data Exchange (ETDEWEB)

    Hargrove, Tatiana Y.; Wawrzak, Zdzislaw; Liu, Jialin; Nes, W. David; Waterman, Michael R.; Lepesheva, Galina I. (Vanderbilt); (TTU); (NWU)

    2012-05-14

    Leishmaniasis is a major health problem that affects populations of {approx}90 countries worldwide, with no vaccine and only a few moderately effective drugs. Here we report the structure/function characterization of sterol 14{alpha}-demethylase (CYP51) from Leishmania infantum. The enzyme catalyzes removal of the 14{alpha}-methyl group from sterol precursors. The reaction is essential for membrane biogenesis and therefore has great potential to become a target for antileishmanial chemotherapy. Although L. infantum CYP51 prefers C4-monomethylated sterol substrates such as C4-norlanosterol and obtusifoliol (V{sub max} of {approx}10 and 8 min{sup -1}, respectively), it is also found to 14{alpha}-demethylate C4-dimethylated lanosterol (V{sub max} = 0.9 min{sup -1}) and C4-desmethylated 14{alpha}-methylzymosterol (V{sub max} = 1.9 min{sup -1}). Binding parameters with six sterols were tested, with K{sub d} values ranging from 0.25 to 1.4 {mu}m. Thus, L. infantum CYP51 is the first example of a plant-like sterol 14{alpha}-demethylase, where requirements toward the composition of the C4 atom substituents are not strict, indicative of possible branching in the postsqualene portion of sterol biosynthesis in the parasite. Comparative analysis of three CYP51 substrate binding cavities (Trypanosoma brucei, Trypanosoma cruzi, and L. infantum) suggests that substrate preferences of plant- and fungal-like protozoan CYP51s largely depend on the differences in the enzyme active site topology. These minor structural differences are also likely to underlie CYP51 catalytic rates and drug susceptibility and can be used to design potent and specific inhibitors.

  9. Fundamentals of fluorescence and fluorescence microscopy.

    Science.gov (United States)

    Wolf, David E

    2013-01-01

    This chapter discusses the fundamental physics of fluorescence. The application of fluorescence to microscopy represents an important transition in the development of microscopy, particularly as it applies to biology. It enables quantitating the amounts of specific molecules within a cell, determining whether molecules are complexing on a molecular level, measuring changes in ionic concentrations within cells and organelles, and measuring molecular dynamics. This chapter also discusses the issues important to quantitative measurement of fluorescence and focuses on four of quantitative measurements of fluorescence--boxcar-gated detection, streak cameras, photon correlation, and phase modulation. Although quantitative measurement presents many pitfalls to the beginner, it also presents significant opportunities to one skilled in the art. This chapter also examines how fluorescence is measured in the steady state and time domain and how fluorescence is applied in the modern epifluorescence microscope.

  10. Effects of a Plant Sterol or Stanol Enriched Mixed Meal on Postprandial Lipid Metabolism in Healthy Subjects

    Science.gov (United States)

    Baumgartner, Sabine; Mensink, Ronald P.; Plat, Jogchum

    2016-01-01

    Background Evidence is increasing that plant sterols and stanols not only lower fasting serum low-density lipoprotein concentrations, but also those of triglycerides (TG). Insight into effects of these components on postprandial TG metabolism, an emerging risk factor for cardiovascular disease, is missing. Objective Our objective was to examine the 8-hour postprandial response after consuming plant sterol or stanol enriched margarine as part of a mixed meal. Methods This postprandial study was part of a randomized crossover study in which 42 subjects consumed plant sterol enriched (3 g/d plant sterols), plant stanol enriched (3 g/d plant stanols), and control margarines for 4 weeks. After each period, subjects consumed a shake enriched with 3g plant sterols (sterol period), 3g plant stanols (stanol period) or no addition (control period). Subjects received a second shake with no addition after 4 hours. Results TG and apoB48 incremental areas under the curves (iAUC) of the total (0-8h) and 1st meal response (0-4h) were comparable between the meals and in all age categories (I:18-35y, II:36-52y, III:53-69y). In subjects aged 53-69y, TG iAUC after the 2nd meal (4-8h) was higher in the stanol period as compared with the sterol (63.1±53.0 mmol/L/min; P sterol period (67.1±77.0 mg/L/min; P < 0.05) and tended to be higher than after the control period (43.1±64.5 mg/L/min; P = 0.08) in subjects aged 53-69y. These increased postprandial responses may be due to reduced lipoprotein lipase activity, since postprandial apoCIII/II ratios were increased after stanol consumption compared with the control meal. Conclusion Postprandial TG and apoB48 responses are age-dependently increased after plant stanol consumption, which might be related to a changed clearance of triglyceride-rich lipoproteins. Trial Registration ClinicalTrials.gov NCT01559428 PMID:27611192

  11. Synthesis of Hydroxylated Sterols(Ⅱ)--Synthesis of 24-Methylenecholest-4-en-3β,6α-diol

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ In our study on the soft coral,Alcyonium patagonicum,a new hydroxylated sterol,24-methylenecholest-4-en-3β,6α-diol(1) exhibiting a potent activity to murine leukemia cells(IC50=1 μg/mL) has been isolated[1] and synthesized[2,3].As a part of our studies on the relationship between the chemical structure and the biological activity of the hydroxylated sterols,the synthesis of 24-methylenecholest-4-en-3β,6α-diol(2) is reported here.

  12. Towards squalamine mimics: synthesis and antibacterial activities of head-to-tail dimeric sterol-polyamine conjugates.

    Science.gov (United States)

    Chen, Wen-Hua; Wennersten, Christine; Moellering, Robert C; Regen, Steven L

    2013-03-01

    Four dimeric sterol-polyamine conjugates have been synthesized from the homo- and hetero-connection of monomeric sterol-polyamine analogs in a head-to-tail manner. These dimeric conjugates show strong antibacterial activity against a broad spectrum of Gram-positive bacteria, whereas their corresponding activities against Gram-negative bacteria are relatively moderate. Though no significant difference was observed in the activities of these conjugates, cholic acid-containing dimeric conjugates generally exhibit higher activities than the corresponding deoxycholic acid-derived analogs. This is in contrast to the finding that a monomeric deoxycholic acid-spermine conjugate was more active than the corresponding cholic acid-derived analog.

  13. Effect of rapeseed oil derived plant sterol and stanol esters on atherosclerosis parameters in cholesterol challenged heterozygous Watanabe Heritable Hyperlipidemic rabbits

    DEFF Research Database (Denmark)

    Schrøder, Malene; Fricke, Christiane; Pilegaard, Kirsten

    2009-01-01

    Rapeseed oil (RSO) is a novel source of plant sterols, containing the unique brassicasterol in concentrations higher than allowed for plant sterol blends in food products in the European Union. Effects of RSO sterols and stanols on aortic atherosclerosis were studied in cholesterol-fed heterozygous...... Watanabe heritable hyperlipidaemic (Hh-WHHL) rabbits. Four groups (n 18 per group) received a cholesterol-added (2 g/kg) standard chow or this diet with added RSO stanol esters (17 g/kg), RSO stanol esters (34 g/kg) or RSO sterol esters (34 g/kg) for 18 weeks. Feeding RSO stanol esters increased plasma...... campestanol (P sterol esters increased concentrations of plasma campesterol (P

  14. Acute sterol o-acyltransferase 2 (SOAT2 knockdown rapidly mobilizes hepatic cholesterol for fecal excretion.

    Directory of Open Access Journals (Sweden)

    Stephanie M Marshall

    Full Text Available The primary risk factor for atherosclerotic cardiovascular disease is LDL cholesterol, which can be reduced by increasing cholesterol excretion from the body. Fecal cholesterol excretion can be driven by a hepatobiliary as well as a non-biliary pathway known as transintestinal cholesterol efflux (TICE. We previously showed that chronic knockdown of the hepatic cholesterol esterifying enzyme sterol O-acyltransferase 2 (SOAT2 increased fecal cholesterol loss via TICE. To elucidate the initial events that stimulate TICE, C57Bl/6 mice were fed a high cholesterol diet to induce hepatic cholesterol accumulation and were then treated for 1 or 2 weeks with an antisense oligonucleotide targeting SOAT2. Within 2 weeks of hepatic SOAT2 knockdown (SOAT2HKD, the concentration of cholesteryl ester in the liver was reduced by 70% without a reciprocal increase in hepatic free cholesterol. The rapid mobilization of hepatic cholesterol stores resulted in a ∼ 2-fold increase in fecal neutral sterol loss but no change in biliary cholesterol concentration. Acute SOAT2HKD increased plasma cholesterol carried primarily in lipoproteins enriched in apoB and apoE. Collectively, our data suggest that acutely reducing SOAT2 causes hepatic cholesterol to be swiftly mobilized and packaged onto nascent lipoproteins that feed cholesterol into the TICE pathway for fecal excretion.

  15. Structural Insights into Inhibition of Sterol 14[alpha]-Demethylase in the Human Pathogen Trypanosoma cruzi

    Energy Technology Data Exchange (ETDEWEB)

    Lepesheva, Galina I.; Hargrove, Tatiana Y.; Anderson, Spencer; Kleshchenko, Yuliya; Furtak, Vyacheslav; Wawrzak, Zdzislaw; Villalta, Fernando; Waterman, Michael R. (Vanderbilt); (NWU); (Meharry)

    2010-09-02

    Trypanosoma cruzi causes Chagas disease (American trypanosomiasis), which threatens the lives of millions of people and remains incurable in its chronic stage. The antifungal drug posaconazole that blocks sterol biosynthesis in the parasite is the only compound entering clinical trials for the chronic form of this infection. Crystal structures of the drug target enzyme, Trypanosoma cruzi sterol 14{alpha}-demethylase (CYP51), complexed with posaconazole, another antifungal agent fluconazole and an experimental inhibitor, (R)-4{prime}-chloro-N-(1-(2,4-dichlorophenyl)-2-(1H-imid-azol-1-yl)ethyl)biphenyl-4-carboxamide (VNF), allow prediction of important chemical features that enhance the drug potencies. Combined with comparative analysis of inhibitor binding parameters, influence on the catalytic activity of the trypanosomal enzyme and its human counterpart, and their cellular effects at different stages of the Trypanosoma cruzi life cycle, the structural data provide a molecular background to CYP51 inhibition and azole resistance and enlighten the path for directed design of new, more potent and selective drugs to develop an efficient treatment for Chagas disease.

  16. Sterols associated with small unilamellar vesicles (SUVs): intrinsic mobility role for 1H NMR detection.

    Science.gov (United States)

    Mouret, Liza; Da Costa, Grégory; Bondon, Arnaud

    2014-07-01

    Small unilamellar vesicles (SUVs) of phospholipids are often used as a membrane model system for studying the interaction of molecules. When using NMR under the standard liquid-state conditions, SUV phospholipid proton spectra can be recorded, exhibiting sharp signals. This is not only because of the fast vesicular tumbling but also because of the combination of this tumbling with the individual motion of the lipids inside the bilayer. This appears evident because addition of cholesterol is responsible of broader resonances because of the slowing down of the lipid motion. On the other hand, no (1)H signal is detected for cholesterol in the bilayer. This lack of detection of the inserted molecules explains why generally SUVs are not considered as a good model for NMR studies under the standard liquid-state conditions. Here, we use two other sterols in order to demonstrate that an increase of the molecular mobility inside the bilayer could allow the detection of their proton resonances. For desmosterol and lanosterol, which show higher mobility inside the bilayer, with increasing lateral diffusion rates, (1)H sterol signals are detected in contrast to cholesterol. For the fast diffusing lanosterol, no significant improvement in detection is observed using deuterated lipids, demonstrating that homonuclear dipolar coupling is fully averaged out. Furthermore, in the case of low mobility such as for cholesterol, the use of a fast magic angle spinning probe is shown to be efficient to recover the full proton spectrum. Copyright © 2014 John Wiley & Sons, Ltd.

  17. Alpha-amylase inhibitory activity and sterol composition of the marine algae, Sargassum glaucescens.

    Science.gov (United States)

    Payghami, Nasrin; Jamili, Shahla; Rustaiyan, Abdolhossein; Saeidnia, Soodabeh; Nikan, Marjan; Gohari, Ahmad Reza

    2014-01-01

    Sargassum species (phaeophyceae) are economically important brown algae in southern parts of Iran. Sargassum is mainly harvested as a row material in alginate production industries and is a source of plant foods or plant bio-stimulants even a component of animal foods. In this study, Sargassum glaucescens, collected from the seashore of Chabahar, was employed for phytochemical and biological evaluations. For that purpose, the dried algae was extracted by methanol and subjected to different chromatographic separation methods. Six sterols, fucosterol (1), 24(S)-hydroxy-24-vinylcholesterol (2), 24(R)-hydroxy-24-vinylcholesterol (3), stigmasterol (4), β-sitosterol (5) and cholesterol (6) were identified by spectroscopic methods including (1)H-NMR, (13)C-NMR and mass spectroscopy. In vitro alpha-amylase inhibitory test was performed on the methanolic extract and the results revealed a potent inhibition (IC50 = 8.9 ± 2.4 mg/mL) of the enzyme compared to acarbose as a positive control. Various biological activities and distribution of sterols in Sargassum genus have been critically reviewed here. The results concluded that these algae are a good candidate for further anti-diabetic investigations in animals and human.

  18. Sterols from Mytilidae show anti-aging and neuroprotective effects via anti-oxidative activity.

    Science.gov (United States)

    Sun, Yujuan; Lin, Yanfei; Cao, Xueli; Xiang, Lan; Qi, Jianhua

    2014-11-25

    For screening anti-aging samples from marine natural products, K6001 yeast strain was employed as a bioassay system. The active mussel extract was separated to give an active sterol fraction (SF). SF was further purified, and four sterol compounds were obtained. Their structures were determined to be cholesterol (CHOL), brassicasterol, crinosterol, and 24-methylenecholesterol. All compounds showed similar anti-aging activity. To understand the action mechanism involved, anti-oxidative experiments, reactive oxygen species (ROS) assays, and malondialdehyde (MDA) tests were performed on the most abundant compound, CHOL. Results indicated that treatment with CHOL increases the survival rate of yeast under oxidative stress and decreases ROS and MDA levels. In addition, mutations of uth1, skn7, sod1, and sod2, which feature a K6001 background, were employed and the lifespans of the mutations were not affected by CHOL. These results demonstrate that CHOL exerts anti-aging effects via anti-oxidative stress. Based on the connection between neuroprotection and anti-aging, neuroprotective experiments were performed in PC12 cells. Paraquat was used to induce oxidative stress and the results showed that the CHOL and SF protect the PC12 cells from the injury induced by paraquat. In addition, these substance exhibited nerve growth factor (NGF) mimic activities again confirmed their neuroprotective function.

  19. Neutron diffraction studies of the interaction between amphotericin B and lipid-sterol model membranes

    Science.gov (United States)

    Foglia, Fabrizia; Lawrence, M. Jayne; Demeė, Bruno; Fragneto, Giovanna; Barlow, David

    2012-10-01

    Over the last 50 years or so, amphotericin has been widely employed in treating life-threatening systemic fungal infections. Its usefulness in the clinic, however, has always been circumscribed by its dose-limiting side-effects, and it is also now compromised by an increasing incidence of pathogen resistance. Combating these problems through development of new anti-fungal agents requires detailed knowledge of the drug's molecular mechanism, but unfortunately this is far from clear. Neutron diffraction studies of the drug's incorporation within lipid-sterol membranes have here been performed to shed light on this problem. The drug is shown to disturb the structures of both fungal and mammalian membranes, and co-localises with the membrane sterols in a manner consistent with trans-membrane pore formation. The differences seen in the membrane lipid ordering and in the distributions of the drug-ergosterol and drug-cholesterol complexes within the membranes are consistent with the drug's selectivity for fungal vs. human cells.

  20. Crystallographic and NMR studies on sterols from green alga Chaetomorpha basiretorsa Setchell

    Institute of Scientific and Technical Information of China (English)

    SHI Dayong; XU Feng; HE Juan; SHI Jiangong; FAN Xiao; HAN Lijun

    2008-01-01

    Chemical investigation of the ethanol extract of the marine green alga Chaetomorpha basiretorsa Setchell led to the isolation of a new sterol stigrnast-4,28-dien-3α,6β-diol 1 in addition to the five known sterols of β-1awsaritol 2,saringosterol 3,24-hydroper- oxy-24-vinyl-cholesterol 4,β-stigmasterol 5,29-hydroxystigmasta-5,24(28)-dien-3β-ol 6.Compounds were isolated by normal phase silica gel and Scphadex LH-20 gel colum chromatography,reverse phase HPLC and recrystalization.Their structures were elucidated by spectroscopic methods including MS,IR 1D/2D NMR and X-ray analysis.Cytotoxicity of compounds was screened by using the standard MTT method.All these compounds were isolated from the green alga Chaetomorpha basiretorsa Setchell for the first time and they were inactive (50% inhibitory concentration was greater than 10 μg/cm3) against KB,Bel-7402,PC- 3M,Ketr 3 and MCF-7 cell lines.

  1. Targeting Ergosterol biosynthesis in Leishmania donovani: essentiality of sterol 14 alpha-demethylase.

    Directory of Open Access Journals (Sweden)

    Laura-Isobel McCall

    2015-03-01

    Full Text Available Leishmania protozoan parasites (Trypanosomatidae family are the causative agents of cutaneous, mucocutaneous and visceral leishmaniasis worldwide. While these diseases are associated with significant morbidity and mortality, there are few adequate treatments available. Sterol 14alpha-demethylase (CYP51 in the parasite sterol biosynthesis pathway has been the focus of considerable interest as a novel drug target in Leishmania. However, its essentiality in Leishmania donovani has yet to be determined. Here, we use a dual biological and pharmacological approach to demonstrate that CYP51 is indispensable in L. donovani. We show via a facilitated knockout approach that chromosomal CYP51 genes can only be knocked out in the presence of episomal complementation and that this episome cannot be lost from the parasite even under negative selection. In addition, we treated wild-type L. donovani and CYP51-deficient strains with 4-aminopyridyl-based inhibitors designed specifically for Trypanosoma cruzi CYP51. While potency was lower than in T. cruzi, these inhibitors had increased efficacy in parasites lacking a CYP51 allele compared to complemented parasites, indicating inhibition of parasite growth via a CYP51-specific mechanism and confirming essentiality of CYP51 in L. donovani. Overall, these results provide support for further development of CYP51 inhibitors for the treatment of visceral leishmaniasis.

  2. Direct analysis of sterols by derivatization matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and tandem mass spectrometry.

    Science.gov (United States)

    Hailat, Iyad; Helleur, Robert J

    2014-01-30

    Free sterols are neutral molecules that are difficult to analyze by MALDI or ESI and their molecular ions easily fragment. In order to increase their ionization efficiency and selectivity, sterols were derivatized by different reagents. Selected sterols were converted into their corresponding picolinyl esters, N-methylpyridyl ethers and sulphated esters. The derivatives were optimized for MALDI-TOFMS analysis through proper selection of the matrix. MALDI-TOF/TOF experiments were carried out to study the fragmentation pathways of the derivatives and their use in structural elucidation. Lipid extracts from mussels were used as test samples for MALDI analysis of sterols in biological samples also analyzed by GC/MS for comparison. Sterol picolinyl esters were identified as sodiated adducts [M+Na](+) and the signal significantly enhanced after addition of sodium acetate (20 mM). Sterol N-methylpyridyl ethers were easily detected as [M](+) while sulphated sterols were best detected as [M-H](-). The ester bonds of picolinyl and sulphated esters easily cleaved in MS/MS resulting in diagnostic derivative fragments at m/z 146.03 and 96.89, respectively. Cleavage of the ether bond of N-methylpyridyl ethers gave a diagnostic fragment ion at m/z 110.04. Sterol profiles in mussels obtained by MALDI-TOFMS were in close agreement with those obtained by GC/MS. Two sterols (cholesterol and β-sitosterol) were selected for quantification as their sulphated and picolinyl esters. Calibration curves gave excellent correlation coefficients. Suitable matrices for picolinyl esters are DHB and THAP, for N-methylpyridyl ethers THAP, and for sulphated esters p-nitroaniline and dithranol. Using cholesterol, the limits of detection (LODs) for sulphated esters were 0.2 µg/mL and for picolinyl esters, 1.5 µg/mL. N-Methylpyridyl ethers were found unsuitable for sterol quantitation. Copyright © 2013 John Wiley & Sons, Ltd.

  3. “Profiling Sterols in Cerebrotendinous Xanthomatosis: Utility of Girard Derivatization and High Resolution Exact Mass LC-ESI-MSn Analysis”

    Science.gov (United States)

    Sandlers, Yana; Pappu, Anuradha S.; Merkens, Louise S.; Duell, Barton; Lear, Steven R.; Erickson, Sandra K.; Steiner, Robert D.

    2011-01-01

    In this study we profile free 3-oxo sterols present in plasma from patients affected with the neurodegenerative disorder of sterol and bile acid metabolism cerebrotendinous xanthomatosis (CTX), utilizing a combination of charge-tagging and LC-ESI-MSn performed with an LTQ-Orbitrap Discovery instrument. In addition, we profile sterols in plasma from 24 month old cyp27A1 gene knockout mice lacking the enzyme defective in CTX. Charge-tagging was accomplished by reaction with cationic Girard's P (GP) reagent 1-(carboxymethyl) pyridinium chloride hydrazide, an approach uniquely suited to studying the 3-oxo sterols that accumulate in CTX, as Girard's reagent reacts with the sterol oxo moiety to form charged hydrazone derivatives. The ability to selectively generate GP-tagged 3-oxo-4-ene and 3-oxo-5(H) saturated plasma sterols enabled ESI-MSn analysis of these sterols in the presence of a large excess (3 orders of magnitude) of cholesterol. Often cholesterol detected in biological samples makes it challenging to quantify minor sterols, with cholesterol frequently removed prior to analysis. We derivatized plasma (10μl) without SPE removal of cholesterol to ensure detection of all sterols - present in plasma. We were able to measure 4-cholesten-3-one in plasma from untreated CTX patients (1207 ± 302 ng/ml, mean ± SD, n=4), as well as other intermediates in a proposed pathway to 5αa-cholestanol. In addition, a number of bile acid precursors were identified in plasma using this technique. GP-tagged sterols were identified utilizing high resolution exact mass spectra (± 5 ppm), as well as MS2 ([M]+→) spectra that possessed characteristic neutral loss of 79 Da (pyridine) fragment ions, and MS3 ([M]+→[M-79]+→) spectra that provided additional structurally informative fragment ions. PMID:21168372

  4. Reviews in fluorescence 2010

    CERN Document Server

    Geddes, Chris D

    2011-01-01

    ""Reviews in Fluorescence 2010"", the seventh volume of the book serial from Springer, serves as a comprehensive collection of current trends and emerging hot topics in the field of fluorescence and closely related disciplines. It summarizes the year's progress in fluorescence and its applications, with authoritative analytical reviews specialized enough to be attractive to professional researchers, yet also appealing to the wider audience of scientists in related disciplines of fluorescence. ""Reviews in Fluorescence"" offers an essential reference material for any lab working in the fluoresc

  5. Principles of fluorescence techniques

    CERN Document Server

    2016-01-01

    Fluorescence techniques are being used and applied increasingly in academics and industry. The Principles of Fluorescence Techniques course will outline the basic concepts of fluorescence techniques and the successful utilization of the currently available commercial instrumentation. The course is designed for students who utilize fluorescence techniques and instrumentation and for researchers and industrial scientists who wish to deepen their knowledge of fluorescence applications. Key scientists in the field will deliver theoretical lectures. The lectures will be complemented by the direct utilization of steady-state and lifetime fluorescence instrumentation and confocal microscopy for FLIM and FRET applications provided by leading companies.

  6. Effects of plant stanol ester consumption on fasting plasma oxy(phyto)sterol concentrations as related to fecal microbiota characteristics

    NARCIS (Netherlands)

    Baumgartner, Sabine; Mensink, Ronald P.; Smet, De Els; Konings, Maurice; Fuentes Enriquez de Salamanca, Susana; Vos, de Willem M.; Plat, Jogchum

    2016-01-01

    Information regarding dietary effects on plasma oxyphytosterol concentrations as well as on the origin of oxyphytosterols is scarce. We hypothesized that plant sterols are oxidized in the intestinal lumen, mediated by microbial activity, followed by uptake into the circulation. To address this hy

  7. Use of Enterococcus, BST and sterols as indicators for poultry pollution source tracking in surface and groundwater

    Science.gov (United States)

    This study has applied Enterococcus, Bacterial Source Tracking (BST) and sterol analysis for pollution source identification from poultry sources. Fecal contamination was detected in 100% of surface water and 15% of groundwater sites tested. E. faecium was the dominant species in aged litter sampl...

  8. The effect of plant sterols and different low doses of omega-3 fatty acids from fish oil on lipoprotein subclasses

    NARCIS (Netherlands)

    Jacobs, D.M.; Mihaleva, V.V.; Schalkwijk, D.B. van; Graaf, A.A. de; Vervoort, J.; Dorsten, F.A. van; Ras, R.T.; Demonty, I.; Trautwein, E.A.; Duynhoven, J. van

    2015-01-01

    Scope: Consumption of a low-fat spread enriched with plant sterols (PS) and different low doses (<2 g/day) of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil reduces serum triglycerides (TGs) and low-density lipoprotein-cholesterol (LDL-Chol) and thus beneficially affects

  9. Vitamin D and sterol composition of ten types of mushrooms from retail suppliers in the United States

    Science.gov (United States)

    Vitamin D, ergosterol, ergosterol metabolites, and phytosterols were analyzed in ten mushroom types sampled nationwide in the U.S. to update the USDA Nutrient Database for Standard Reference. Sterols were analyzed by GC-FID with mass spectrometric confirmation of components. Vitamin D was assayed ...

  10. Identification and engineering of cholesterol oxidases involved in the initial step of sterols catabolism in Mycobacterium neoaurum.

    Science.gov (United States)

    Yao, Kang; Wang, Feng-Qing; Zhang, Huai-Cheng; Wei, Dong-Zhi

    2013-01-01

    Mycobacteria have been modified to transform sterols to produce valuable steroids. Here, we demonstrated that the oxidation of sterols to sterones is a rate-limiting step in the catabolic pathway of sterols in Mycobacterium neoaurum. Two cholesterol oxidases ChoM1 and ChoM2 involved in the step were identified in M. neoaurum and the ChoM2 shared up to 45% identity with other cholesterol oxidases. We demonstrated that the combination of ChoM1 and ChoM2 plays a significant role in this step. Accordingly, we developed a strategy to overcome this rate-limiting step by augmenting the activity of cholesterol oxidases in M. neoaurum strains to enhance their transformation productivity of sterols to valuable steroids. Our results indicated that the augmentation of ChoM2 achieved 5.57g/l androst-1,4-diene-3,17-dione in M. neoaurum NwIB-01MS and 6.85g/l androst-4-ene-3,17-dione in M. neoaurum NwIB-R10, greatly higher than the original yield, 3.87g/l androst-1,4-diene-3,17-dione and 4.53g/l androst-4-ene-3,17-dione, respectively. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Lamellar self-assemblies of single-chain amphiphiles and sterols and their derived liposomes: distinct compositions and distinct properties.

    Science.gov (United States)

    Cui, Zhong-Kai; Lafleur, Michel

    2014-02-01

    Typically, single-chain amphiphiles and sterols do not form fluid lamellar phases once hydrated individually. Most of the single-chain amphiphiles form actually micelles in aqueous environments, while sterols display a very limited solubility in water. However, under certain conditions, mixtures of single-chain amphiphiles and sterols lead to the formation of stable fluid bilayers. Over the past decade, several of these systems leading to fluid lamellar self-assemblies have been identified and this article reviews the current knowledge relative to these non-phospholipid bilayers made of single-chain amphiphiles and sterols. It presents an integrated view about the molecular features that are required for their stability, the properties they share, and the origin of these characteristics. It was also shown that these lamellar systems could lead to the formation of unilamellar vesicles, similar to phospholipid based liposomes. These vesicles display distinct properties that make them potentially appealing for technological applications; they display a limited permeability, they are stable, they are formed with molecules that are relatively chemically inert (and relatively cheap), and they can be readily functionalized. The features of these distinct liposomes and their technological applications are reviewed. Finally, the putative biological implications of these non-phospholipid fluid bilayers are also discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Faecal sterols as sewage markers in the Langat River, Malaysia: Integration of biomarker and multivariate statistical approaches

    Institute of Scientific and Technical Information of China (English)

    Nur Hazirah Adnan; Mohamad Pauzi Zakaria; Hafizan Juahir; Masni Mohd Ali

    2012-01-01

    The Langat River in Malaysia has been experiencing anthropogenic input from urban,rural and industrial activities for many years.Sewage contamination,possibly originating from the greater than three million inhabitants of the Langat River Basin,were examined.Sediment samples from 22 stations (SL01-SL22) along the Langat River were collected,extracted and analysed by GC-MS.Six different sterols were identified and quantified.The highest sterol concentration was found at station SL02 (618.29 ng/g dry weight),which situated in the Balak River whereas the other sediment samples ranged between 11.60 and 446.52 ng/g dry weight.Sterol ratios were used to identify sources,occurrence and partitioning of faecal matter in sediments and majority of the ratios clearly demonstrated that sewage contamination was occurring at most stations in the Langat River.A multivariate statistical analysis was used in conjunction with a combination of biomarkers to better understand the data that clearly separated the compounds.Most sediments of the Langat River were found to contain low to mid-range sewage contamination with some containing ‘significant' levels of contamination.This is the first report on sewage pollution in the Langat River based on a combination of biomarker and multivariate statistical approaches that will establish a new standard for sewage detection using faecal sterols.

  13. The substance composition of sterols in the sediments from the Chukchi Sea, the Bering Sea and global climatic significance

    Institute of Scientific and Technical Information of China (English)

    Lu Bing; Hu Chuanyu; Pan Jianming; Xue Bin; YaoMei

    2006-01-01

    The compounds of sterols such as C27 、C28 、C29 and C3o are recorded from C-8 core of the Chukchi Sea. The double bond position is located at 5-, 5 ,22 as well as 22-,24-. The compound of sterols such as C27、C28、C29 are recorded from B2-9core of the Bering Sea. The double bond position is located at 5-, 5, 22 as well as 22. The composition characteristics of sterols indicate that the substance is mainly contributed by the terrigenous origin and marine silicate organisms. The results are also suggest that the record of abnormal sterols from the surface sediments (2 -0 cm)in the Chukchi Sea and the Bering Sea represent the period from 1980s to the late 1990s. The strong signal of the Arctic warming is preserved in the sediments, which indicates the eco- environmental change responding to climatic effect of circumjacent.

  14. BIOCHEMISTRY OF DINOFLAGELLATE LIPIDS, WITH PARTICULAR REFERENCE TO THE FATTY ACID AND STEROL COMPOSITION OF A KARENIA BREVIS BLOOM

    Science.gov (United States)

    Leblond, Jeffrey D., Terence J. Evens and Peter J. Chapman. 2003. Biochemistry of Dinoflagellate Lipids, with Particular Reference to the Fatty Acid and Sterol Composition of a Karenia brevis Bloom. Phycologia. 42(4):324-331. (ERL,GB 1160). The harmful marine dinoflagella...

  15. Heterogeneous expression of cholesterol 7α-hydroxylase and sterol 27- hydroxylase genes in the rat liver lobulus

    NARCIS (Netherlands)

    Twisk, J.; Hoekman, M.F.M.; Mager, W.H.; Moorman, A.F.M.; Boer, P.A.J. de; Scheja, L.; Princen, H.M.G.; Gebhardt, R.

    1995-01-01

    We investigated the lobular localization and molecular level of expression of cholesterol 7α-hydroxylase and sterol 27-hydroxylase, two key enzymes in bile acid synthesis, in isolated periportal and pericentral hepatocytes and by in situ hybridization of rat liver. Enzyme activity, mRNA, and gene tr

  16. Hair sterol signatures coupled to multivariate data analysis reveal an increased 7β-hydroxycholesterol production in cognitive impairment.

    Science.gov (United States)

    Son, Hyun-Hwa; Lee, Do-Yup; Seo, Hong Seog; Jeong, Jihyeon; Moon, Ju-Yeon; Lee, Jung-Eun; Chung, Bong Chul; Kim, Eosu; Choi, Man Ho

    2016-01-01

    Altered cholesterol metabolism could be associated with cognitive impairment. The quantitative profiling of 19 hair sterols was developed using gas chromatography-mass spectrometry coupled to multivariate data analysis. The limit of quantification of all sterols ranged from 5 to 20 ng/g, while the calibration linearity was higher than 0.98. The precision (% CV) and accuracy (% bias) ranged from 3.2% to 9.8% and from 83.2% to 119.4%, respectively. Among the sterols examined, 8 were quantitatively detected from two strands of 3-cm-long scalp hair samples of female participants, including mild cognitive impairment (MCI, n=15), Alzheimer's disease (AD, n=31), and healthy controls (HC, n=36). The cognitive impairment (MCI or AD) was correlated with a higher metabolic rate than that of HCs based on 7β-hydroxycholesterol (Phair sample metabolic ratios of 7β-hydroxycholesterol to cholesterol, which is an accepted, sensitive, and specific tool for discriminating HCs from individuals with MCI or AD. In conclusion, improved diagnostic values can be obtained using hair sterol signatures coupled with MMSE scores. This method may prove useful for predictive diagnosis in population screening of cognitive impairment.

  17. Serum TG-lowering properties of plant sterols and stanols are associated with decreased hepatic VLDL secretion

    NARCIS (Netherlands)

    Schonewille, Marleen; Brufau Dones, Gemma; Shiri-Sverdlov, Ronit; Groen, Albert K.; Plat, Jogchum

    2014-01-01

    Plant sterols and stanols are structurally similar to cholesterol and when added to the diet they are able to reduce serum total- and LDL-cholesterol concentrations. They also lower serum triglyceride concentrations in humans, particularly under conditions of hypertriglyceridemia. The aim of this

  18. The origin of fetal sterols in second-trimester amniotic fluid : endogenous synthesis or maternal-fetal transport?

    NARCIS (Netherlands)

    Baardman, Maria E.; Erwich, Jan Jaap H. M.; Berger, Rolf M. F.; Hofstra, Robert M. W.; Kerstjens-Frederikse, Wilhelmina S.; Luetjohann, Dieter; Plosch, Torsten; Lutjohann, D.

    2012-01-01

    OBJECTIVE: Cholesterol is crucial for fetal development. To gain more insight into the origin of the fetal cholesterol pool in early human pregnancy, we determined cholesterol and its precursors in the amniotic fluid of uncomplicated, singleton human pregnancies. STUDY DESIGN: Total sterols were cha

  19. BIOCHEMISTRY OF DINOFLAGELLATE LIPIDS, WITH PARTICULAR REFERENCE TO THE FATTY ACID AND STEROL COMPOSITION OF A KARENIA BREVIS BLOOM

    Science.gov (United States)

    Leblond, Jeffrey D., Terence J. Evens and Peter J. Chapman. 2003. Biochemistry of Dinoflagellate Lipids, with Particular Reference to the Fatty Acid and Sterol Composition of a Karenia brevis Bloom. Phycologia. 42(4):324-331. (ERL,GB 1160). The harmful marine dinoflagella...

  20. Online LC-GC analysis of free sterols/stanols and intact steryl/stanyl esters in cereals.

    Science.gov (United States)

    Esche, Rebecca; Scholz, Birgit; Engel, Karl-Heinz

    2013-11-20

    The suitability of online liquid chromatography-gas chromatography for the analysis of free sterols/stanols, steryl/stanyl fatty acid esters, and trans-steryl/stanyl ferulic acid esters in cereals is demonstrated. The silylated lipid extracts were fractionated via liquid chromatography on a normal phase, and the fractions containing the sterol classes were transferred online to the gas chromatograph for the analysis of their individual compositions. The study provides for the first time data on free sterols/stanols and intact steryl/stanyl esters in sweet corn, popcorn, and proso millet. Sweet corn revealed the highest contents of free sterols/stanols and steryl/stanyl fatty acid esters, and popcorn, in turn, the highest amounts of trans-steryl/stanyl ferulic acid esters. The distribution patterns of the proso millet samples revealed pronounced differences from those of sweet corn and popcorn as they particularly exhibited high proportions of free cholesterol and cholesteryl fatty acid esters. Furthermore, no trans-steryl/stanyl ferulic acid esters could be detected.

  1. Serum TG-lowering properties of plant sterols and stanols are associated with decreased hepatic VLDL secretion

    NARCIS (Netherlands)

    Schonewille, Marleen; Brufau Dones, Gemma; Shiri-Sverdlov, Ronit; Groen, Albert K.; Plat, Jogchum

    2014-01-01

    Plant sterols and stanols are structurally similar to cholesterol and when added to the diet they are able to reduce serum total- and LDL-cholesterol concentrations. They also lower serum triglyceride concentrations in humans, particularly under conditions of hypertriglyceridemia. The aim of this st

  2. Effects of Inhibitors of [Delta]24(25)-Sterol Methyl Transferase on the Ultrastructure of Epimastigotes of Trypanosoma cruzi

    Science.gov (United States)

    Braga, Marina V.; Magaraci, Filippo; Orenes Lorente, Silvia; Gilbert, Ian; de Souza, Wanderley

    2005-12-01

    Trypanosoma cruzi is the ethiological agent of Chagas disease. New compounds are being developed based on the biosynthesis and function of sterols, because T. cruzi has a requirement for specific endogenous sterols for growth and survival. Sterol biosynthesis inhibitors (SBIs) are drugs commonly used against fungal diseases. These drugs act by depleting essential and specific membrane components and/or inducing the accumulation of toxic intermediary or lateral products of the biosynthetic pathway. In this work we present the effects of WSP488, WSP501, and WSP561, specific inhibitors of [Delta]24(25)-sterol methyl transferase, on the ultrastructure of T. cruzi epimastigotes. All three drugs inhibited parasite multiplication at low concentrations, with IC50 values of 0.48, 0.44, and 0.48 [mu]M, respectively, and induced marked morphological changes including (a) blockage of cell division; (b) swelling of the mitochondrion, with several projections and depressions; (c) swelling of the perinuclear space; (d) presence of autophagosomes and myelin-like figures; (e) enlargement of the flagellar pocket and of a cytoplasmic vacuole located in close association with the flagellar pocket; (f) detachment of the membrane of the cell body; and (g) formation of a vesicle at the surface of the parasite between the flagellar pocket and the cytostome. Our results show that these drugs are potent in vitro inhibitors of growth of T. cruzi.

  3. Sebaceous lipid profiling of bat integumentary tissues: quantitative analysis of free Fatty acids, monoacylglycerides, squalene, and sterols.

    Science.gov (United States)

    Pannkuk, Evan L; Gilmore, David F; Fuller, Nathan W; Savary, Brett J; Risch, Thomas S

    2013-12-01

    White-nose syndrome (WNS) is a fungal disease caused by Pseudogymnoascus destructans and is devastating North American bat populations. Sebaceous lipids secreted from host integumentary tissues are implicated in the initial attachment and recognition of host tissues by pathogenic fungi. We are interested in determining if ratios of lipid classes in sebum can be used as biomarkers to diagnose severity of fungal infection in bats. To first establish lipid compositions in bats, we isolated secreted and integral lipid fractions from the hair and wing tissues of three species: big brown bats (Eptesicus fuscus), Eastern red bats (Lasiurus borealis), and evening bats (Nycticeius humeralis). Sterols, FFAs, MAGs, and squalene were derivatized as trimethylsilyl esters, separated by gas chromatography, and identified by mass spectrometry. Ratios of sterol to squalene in different tissues were determined, and cholesterol as a disease biomarker was assessed. Free sterol was the dominant lipid class of bat integument. Squalene/sterol ratio is highest in wing sebum. Secreted wing lipid contained higher proportions of saturated FFAs and MAGs than integral wing or secreted hair lipid. These compounds are targets for investigating responses of P. destructans to specific host lipid compounds and as biomarkers to diagnose WNS. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

  4. Fluorescence correlation spectroscopy

    NARCIS (Netherlands)

    Hink, M.A.; Verveer, P.J.

    2015-01-01

    Fluorescence fluctuation spectroscopy techniques allow the quantification of fluorescent molecules present at the nanomolar concentration level. After a brief introduction to the technique, this chapter presents a protocol including background information in order to measure and quantify the molecul

  5. Safe biodegradable fluorescent particles

    Science.gov (United States)

    Martin, Sue I.; Fergenson, David P.; Srivastava, Abneesh; Bogan, Michael J.; Riot, Vincent J.; Frank, Matthias

    2010-08-24

    A human-safe fluorescence particle that can be used for fluorescence detection instruments or act as a safe simulant for mimicking the fluorescence properties of microorganisms. The particle comprises a non-biological carrier and natural fluorophores encapsulated in the non-biological carrier. By doping biodegradable-polymer drug delivery microspheres with natural or synthetic fluorophores, the desired fluorescence can be attained or biological organisms can be simulated without the associated risks and logistical difficulties of live microorganisms.

  6. Incomplete sterols and hopanoids pathways in ciliates: gene loss and acquisition during evolution as a source of biosynthetic genes.

    Science.gov (United States)

    Tomazic, Mariela L; Poklepovich, Tomas J; Nudel, Clara B; Nusblat, Alejandro D

    2014-05-01

    Polycyclic triterpenoids, such as sterols and hopanoids, are essential components of plasmatic membrane in eukaryotic organisms. Although it is generally assumed that ciliates do not synthesize sterols, and many of them are indeed auxotrophic, a large set of annotated genomic sequences and experimental data from recently studied organisms indicate that they can carry putative genes and respond to the presence/absence of precursors in various ways. The pre-squalene pathway, for instance, is largely present in all sequenced ciliates except in Ichthyophthirius multifiliis; although Paramecium tetraurelia lacks the squalene synthase and Oxytricha trifallax the squalene hopene synthase, in addition to the former. On the other hand, the post-squalene pathway, requiring oxygen in several steps, is mostly incomplete in all ciliates analyzed. Nevertheless, a number of predicted genes, with high sequence similarity to C-4 methyl oxidase/s, C-14 demethylase, C-5 and C-7 desaturases and C-24 reductase of sterols are found in Tetrahymena and Paramecium, and scattered in other Stichotrichia ciliates. Moreover, several of these sequences are present in multiples paralogs, like the C-7 desaturase in Paramecium, that carries six versions of the only one present in Tetrahymena. The phylogenetic analyses suggest a mixed origin for the genes involved in the biosynthesis of sterols and surrogates in this phylum; while the genes encoding enzymes of the pre-squalene pathway are most likely of bacterial origin, those involved in the post-squalene pathway, including the processing of sterols obtained from the environment, may have been partially retained or acquired indistinctly from lower eukaryotes or prokaryotes. This particular combination of diverse gene/s acquisition patterns allows for survival in conditions of poor oxygen availability, in which tetrahymanol and other hopanoids may be advantageous, but also conditions of excess oxygen availability and abundant sterols, in which the

  7. Sterol-inhibiting fungicide impacts on soil microbial ecology in Atlantic Coastal Plain soils

    Science.gov (United States)

    White, P. M.; Potter, T. L.; Strickland, T. C.

    2008-12-01

    Seventy-five percent of the peanuts (Arachus hypogaia) produced in the United States are grown in the Atlantic Coastal Plain region. Portions of this area, including Alabama and Georgia, exhibit a subtropical climate that promotes soil-borne plant fungal diseases. Most fields receive repeated fungicide applications during the growing season to suppress the disease causing organisms, such as Sclerotium rolfsii, Rhizoctonia solani, and Cylindrocladium parasiticum. Information regarding fungicide effects on the soil microbial community, with components principally responsible for transformation and fate of fungicides and other soil-applied pesticides, is limited. The objectives of the study were to assess soil microbial community response to (1) varying rates of the sterol-inhibiting fungicide tebuconazole (0, single application, season max, 2x season max), and (2) field rates of the sterol-inhibitors cyproconazole, prothioconazole, tebuconazole, and flutriafol, and thiol-competitor chlorothalonil. The sterol-inhibitors exhibited different half lives, as listed in the FOOTPRINT database, ranging from 1300 d. Chlorothalonil was chosen because it is the most frequently applied fungicide to peanut. Shifts in the fungi, gram positive and gram negative bacteria, were monitored during the experiments using phospholipid fatty acid (PLFA) profiles. Ergosterol levels and pesticide decay rates were also monitored to evaluate the effectiveness of the fungicide and soil residence time, respectively. In the rate study, the highest rate of tebuconazole reduced the fungal biomarker 18:2ω6,9c to 2.6 nmol g-1 dry soil at 17 d, as compared to the control (4.1 nmol g-1 dry soil). However, levels of the fungal PLFA biomarker were similar regardless of rate at 0 and 32 d. The gram negative bacterial PLFA mole percent was greater at 17 d for the two highest rates of tebuconazole, but was similar at 0 and 32 d. Gram positive and fungal mole percents were not affected at any time point

  8. Miscibility and interactions of animal and plant sterols with choline plasmalogen in binary and multicomponent model systems.

    Science.gov (United States)

    Hąc-Wydro, Katarzyna; Luty, Katarzyna

    2014-04-01

    In this work miscibility and interactions of sterols with choline plasmalogen (PC-plasm) in Langmuir monolayers were studied. Moreover, the properties of cholesterol/phosphatidylcholine/plasmalogen mixtures of different PC-plasm concentration were investigated. The foregoing systems were treated as a model of cancer cell membranes, which are of higher plasmalogen level than normal cells. Finally, the influence of β-sitosterol and stigmasterol (phytosterols differing in anticancer potency) on these mixtures was verified. The properties of monolayers were analyzed based on the parameters derived from the surface pressure-area isotherms and images taken with Brewster Angle Microscope. It was found that at 30% of sterol in sterol/plasmalogen monolayer the lipids are immiscible and 3D crystallites are formed within the film. Cholesterol molecules mix favorably with PC-plasm at Xchol ≥ 0.5, while the investigated phytosterols only at their prevailing proportion in binary system. The increase of choline plasmalogen in cholesterol/phosphatidylcholine monolayer causes destabilization of the system. Moreover, the incorporation of phytosterols into cholesterol/phosphatidylcholine+PC-plasm mixtures disturbed membrane morphology and this effect was stronger for β-sitosterol as compared to stigmasterol. It was concluded that the presence of vinyl ether bond at sn-1 position in PC-plasm molecule strongly affects miscibility of choline plasmalogen with sterols. The comparison of the collected data with those reported in literature allowed one to conclude that miscibility and interactions of sterols with PC-plasm are less favorable than those with phosphatidylcholine. It was also suggested that overexpression of plasmalogens in cancer cell membranes may be a factor differentiating sensitivity of cells to anticancer effect of phytosterols. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. The effect of methyl jasmonate on triterpene and sterol metabolisms of Centella asiatica, Ruscus aculeatus and Galphimia glauca cultured plants.

    Science.gov (United States)

    Mangas, Susana; Bonfill, Mercè; Osuna, Lidia; Moyano, Elisabeth; Tortoriello, Jaime; Cusido, Rosa M; Piñol, M Teresa; Palazón, Javier

    2006-09-01

    Considering that exogenously applied methyl jasmonate can enhance secondary metabolite production in a variety of plant species and that 2,3-oxidosqualene is a common precursor of triterpenes and sterols in plants, we have studied Centella asiatica and Galphimia glauca (both synthesizing triterpenoid secondary compounds) and Ruscus aculeatus (which synthesizes steroidal secondary compounds) for their growth rate and content of free sterols and respective secondary compounds, after culturing with or without 100 microM methyl jasmonate. Our results show that elicited plantlets of G. glauca and to a higher degree C. asiatica (up to 152-times more) increased their content of triterpenoids directly synthesized from 2,3-oxidosqualene (ursane saponins and nor-seco-friedelane galphimines, respectively) at the same time as growth decreased. In contrast, the free sterol content of C. asiatica decreased notably, and remained practically unaltered in G. glauca. However, in the case of R. aculeatus, which synthesizes steroidal saponins (mainly spirostane type) indirectly from 2,3-oxidosqualene after the latter is converted to the plant phytosterol-precursor cycloartenol, while the growth rate and free sterol content clearly decreased, the spirostane saponine content was virtually unchanged (aerial part) or somewhat lower (roots) in presence of the same elicitor concentration. Our results suggest that while methyl jasmonate may be used as an inducer of enzymes involved in the triterpenoid synthesis downstream from 2,3-oxidosqualene in both C. asiatica and G. glauca plantlets, in those of C. asiatica and R. aculeatus it inhibited the enzymes involved in sterol synthesis downstream from cycloartenol.

  10. In Vitro Antileishmanial Activity of Sterols from Trametes versicolor (Bres. Rivarden).

    Science.gov (United States)

    Leliebre-Lara, Vivian; Monzote Fidalgo, Lianet; Pferschy-Wenzig, Eva-Maria; Kunert, Olaf; Nogueiras Lima, Clara; Bauer, Rudolf

    2016-08-10

    Two ergostanes, 5α,8α-epidioxy-22E-ergosta-6,22-dien-3β-ol (1) and 5α-ergost-7,22-dien-3β-ol (2), and a lanostane, 3β-hydroxylanostan-8,24-diene-21-oic acid (trametenolic acid) (3), were isolated from an n-hexane extract prepared from the fruiting body of Trametes versicolor (Bres. Rivarden). The activity of the isolated sterols was evaluated against promastigotes and amastigotes of Leishmania amazonensis Lainson and Shaw, 1972. The lanostane, compound (3), showed the best inhibitory response (IC50 promastigotes 2.9 ± 0.1 μM and IC50 amastigotes 1.6 ± 0.1 μM). This effect was 25-fold higher compared with its cytotoxic effect on peritoneal macrophages from BALB/c mice. Therefore, trametenolic acid could be regarded as a promising lead for the synthesis of compounds with antileishmanial activity.

  11. Protective immunization against visceral leishmaniasis using Leishmania sterol 24-c-methyltransferase formulated in adjuvant.

    Science.gov (United States)

    Goto, Yasuyuki; Bogatzki, Lisa Y; Bertholet, Sylvie; Coler, Rhea N; Reed, Steven G

    2007-10-16

    We present here the identification and characterization of Leishmania sterol 24-c-methyltransferase (SMT), as well as data on protection of mice immunized with this Ag formulated in MPL-SE. Serological evaluation revealed that SMT is recognized by VL patients. C57BL/6 mice immunized with this vaccine candidate plus MPL-SE showed Ag-specific Th1 immune responses characterized by robust production of IFN-gamma upon specific Ag re-exposure in vitro. Upon challenge with L. infantum, mice immunized with SMT plus MPL-SE showed significant lower parasite burdens in both spleens and livers compared with non-immunized mice or mice injected with adjuvant alone. The results indicate that SMT/MPL-SE can be an effective vaccine candidate for use against VL.

  12. Fatty acids and sterols composition, and antioxidant activity of oils extracted from plant seeds.

    Science.gov (United States)

    Kozłowska, Mariola; Gruczyńska, Eliza; Ścibisz, Iwona; Rudzińska, Magdalena

    2016-12-15

    This study determined and compared the contents of bioactive components in plant seed oils extracted with n-hexane (Soxhlet method) and chloroform/methanol (Folch method) from coriander, caraway, anise, nutmeg and white mustard seeds. Oleic acid dominated among unsaturated fatty acids in nutmeg and anise seed oils while petroselinic acid was present in coriander and caraway oils. Concerning sterols, β-sitosterol was the main component in seed oils extracted with both methods. The content of total phenolics in nutmeg, white mustard and coriander seed oils extracted with chloroform/methanol was higher than in their counterparts prepared with n-hexane. The seed oil samples extracted according to the Folch method exhibited a higher ability to scavenge DPPH radicals compared to the oil samples prepared with the Soxhlet method. DPPH values of the methanolic extracts derived from oils produced with the Folch method were also higher than in the oils extracted with n-hexane.

  13. Two novel C29-5beta-sterols from the stems of Opuntia dillenii.

    Science.gov (United States)

    Jiang, Jianqin; Li, Yanfang; Chen, Zhen; Min, Zhida; Lou, Fengchang

    2006-12-01

    Two novel C29-5beta-sterols, opuntisterol [(24R)-24-ethyl-5beta-cholest-9-ene-6beta,12alpha-diol] (1) and opuntisteroside [(24R)-24-ethyl-6beta-[(beta-d-glucopyranosyl)oxy]-5beta-cholest-9-ene-12alpha-ol] (2), together with nine known compounds, beta-sitosterol (3), taraxerol (4), friedelin (5), methyl linoleate (6), 7-oxositosterol (7), 6beta-hydroxystigmast-4-ene-3-one (8), daucosterol (9), methyl eucomate (10) and eucomic acid (11), were isolated from the stems of Opuntia dillenii collected in Guizhou Province, China. Their structures were elucidated mainly by spectroscopic analysis. The absolute configuration of 1 were deduced from comparative 1H NMR data of the (S)- and (R)-methoxyphenyl acetate derivatives. Compounds 6-8, 10 and 11 were isolated from O. dillenii for the first time.

  14. Plant ecdysteroids: plant sterols with intriguing distributions, biological effects and relations to plant hormones.

    Science.gov (United States)

    Tarkowská, Danuše; Strnad, Miroslav

    2016-09-01

    The present review summarises current knowledge of phytoecdysteroids' biosynthesis, distribution within plants, biological importance and relations to plant hormones. Plant ecdysteroids (phytoecdysteroids) are natural polyhydroxylated compounds that have a four-ringed skeleton, usually composed of either 27 carbon atoms or 28-29 carbon atoms (biosynthetically derived from cholesterol or other plant sterols, respectively). Their physiological roles in plants have not yet been confirmed and their occurrence is not universal. Nevertheless, they are present at high concentrations in various plant species, including commonly consumed vegetables, and have a broad spectrum of pharmacological and medicinal properties in mammals, including hepatoprotective and hypoglycaemic effects, and anabolic effects on skeletal muscle, without androgenic side-effects. Furthermore, phytoecdysteroids can enhance stress resistance by promoting vitality and enhancing physical performance; thus, they are considered adaptogens. This review summarises current knowledge of phytoecdysteroids' biosynthesis, distribution within plants, biological importance and relations to plant hormones.

  15. Screening of Sterol Esterase-producing Strain Chryseobacterium sp.and Its Emzymatic Properties%甾醇酯酶菌株Chryseobacterium sp.的筛选及酶学性质研究

    Institute of Scientific and Technical Information of China (English)

    曾诚; 范远鑫; 丁少军

    2013-01-01

    Twenty four strains for production of sterol esterase were screened from soil by using a plate assay in a medium containing sterol ester as a substrate and rhodamine B as the fluorescent.Among these strains,the jxpLT,which was found to produce the highest level of sterol esterase,belongs to genus Chryseobacterium based on 16S rDNA sequencing analysis and then was designated as Chryseobacterium sp.jxpLT.The maximum enzyme activity of this strain was 0.194 IU/mL after 18 h incubation under the optimized culture conditions.The sterol esterase was preliminary purified by ion exchange chromatography on DEAE Sepharose Fast Flow column and its enzymatic properties were investigated.This enzyme showed an optimum activity at pH 7.5 and 40 ℃.The enzyme had a good stability below 45 ℃ and the pH in 5.0-9.0.Chryseobacterittm sp.jxpLT sterol esterase can hydrolyze cholesterol esters and PNP esters of different fatty acids.It may have the potential to solve the pitch problems caused by lipophilic extractives during wood mechanical pulping process.%设计了一种以植物甾醇酯为底物,罗丹明B为荧光指示剂的平板筛选方法,从土壤中筛选得到24株具有甾醇酯酶活性的菌株,其中编号为jxpLT的菌株具有最高产酶活性,经16S rDNA鉴定表明菌株jxpLT属于金黄杆菌属,命名为Chryseobacterium sp.jxpLT.在优化的产酶条件下,菌株jxpLT培养18h产酶活性最高可达到0.194 IU/mL.初步纯化了Chryseobacterium sp.jxpLT的甾醇酯酶并研究其部分酶学性质,该酶的酶促反应最适温度为40℃,最适pH值为7.5,其在45℃以下,pH值5.0~9.0具有较好的稳定性.该酶对不同碳链长度的脂肪酸胆固醇酯和对硝基苯酚酯具有广泛的底物特异性,显示该甾醇酯酶具有解决机械制浆造纸工艺中树脂障碍问题的潜力.

  16. Conversion of Exogenous Cholesterol into Glycoalkaloids in Potato Shoots, Using Two Methods for Sterol Solubilisation

    Science.gov (United States)

    Petersson, Erik V.; Nahar, Nurun; Dahlin, Paul; Broberg, Anders; Tröger, Rikard; Dutta, Paresh C.; Jonsson, Lisbeth; Sitbon, Folke

    2013-01-01

    Steroidal glycoalkaloids (SGA) are toxic secondary metabolites naturally occurring in the potato, as well as in certain other Solanaceous plant species, such as tomato, eggplant and pepper. To investigate the steroidal origin of SGA biosynthesis, cut potato shoots were fed cholesterol labelled with deuterium (D) in the sterol ring structure (D5- or D6-labelled), or side chain (D7-labelled), and analysed after three or five weeks. The labelled cholesterol and presence of D-labelled SGA were analysed by GC-MS and LC-MS/MS, respectively. When feeding D-labelled cholesterol solubilised in Tween-80, labelled cholesterol in free form became present in both leaves and stems, although the major part was recovered as steryl esters. Minor amounts of D-labelled SGA (α-solanine and α-chaconine) were identified in cholesterol-treated shoots, but not in blank controls, or in shoots fed D6-27-hydroxycholesterol. Solubilising the labelled cholesterol in methyl-β-cyclodextrin instead of Tween-80 increased the levels of labelled SGA up to 100-fold, and about 1 mole% of the labelled cholesterol was recovered as labelled SGA in potato leaves. Both side chain and ring structure D labels were retained in SGA, showing that the entire cholesterol molecule is converted to SGA. However, feeding side chain D7-labelled cholesterol resulted in D5-labelled SGA, indicating that two hydrogen atoms were released during formation of the SGA nitrogen-containing ring system. Feeding with D7-sitosterol did not produce any labelled SGA, indicating that cholesterol is a specific SGA precursor. In conclusion, we have demonstrated a superior performance of methyl-β-cyclodextrin for delivery of cholesterol in plant tissue feeding experiments, and given firm evidence for cholesterol as a specific sterol precursor of SGA in potato. PMID:24349406

  17. Conversion of exogenous cholesterol into glycoalkaloids in potato shoots, using two methods for sterol solubilisation.

    Directory of Open Access Journals (Sweden)

    Erik V Petersson

    Full Text Available Steroidal glycoalkaloids (SGA are toxic secondary metabolites naturally occurring in the potato, as well as in certain other Solanaceous plant species, such as tomato, eggplant and pepper. To investigate the steroidal origin of SGA biosynthesis, cut potato shoots were fed cholesterol labelled with deuterium (D in the sterol ring structure (D5- or D6-labelled, or side chain (D7-labelled, and analysed after three or five weeks. The labelled cholesterol and presence of D-labelled SGA were analysed by GC-MS and LC-MS/MS, respectively. When feeding D-labelled cholesterol solubilised in Tween-80, labelled cholesterol in free form became present in both leaves and stems, although the major part was recovered as steryl esters. Minor amounts of D-labelled SGA (α-solanine and α-chaconine were identified in cholesterol-treated shoots, but not in blank controls, or in shoots fed D6-27-hydroxycholesterol. Solubilising the labelled cholesterol in methyl-β-cyclodextrin instead of Tween-80 increased the levels of labelled SGA up to 100-fold, and about 1 mole% of the labelled cholesterol was recovered as labelled SGA in potato leaves. Both side chain and ring structure D labels were retained in SGA, showing that the entire cholesterol molecule is converted to SGA. However, feeding side chain D7-labelled cholesterol resulted in D5-labelled SGA, indicating that two hydrogen atoms were released during formation of the SGA nitrogen-containing ring system. Feeding with D7-sitosterol did not produce any labelled SGA, indicating that cholesterol is a specific SGA precursor. In conclusion, we have demonstrated a superior performance of methyl-β-cyclodextrin for delivery of cholesterol in plant tissue feeding experiments, and given firm evidence for cholesterol as a specific sterol precursor of SGA in potato.

  18. Formation of Plant Sterol Oxidation Products in Foods during Baking and Cooking Using Margarine without and with Added Plant Sterol Esters.

    Science.gov (United States)

    Lin, Yuguang; Knol, Diny; Menéndez-Carreño, María; Blom, Wendy A M; Matthee, Joep; Janssen, Hans-Gerd; Trautwein, Elke A

    2016-01-27

    Plant sterols (PS) in foods are subject to thermal oxidation to form PS oxidation products (POP). This study measured POP contents of 19 foods prepared by typical household baking and cooking methods using margarines without (control) and with 7.5% added PS (as 12.5% PS-esters, PS-margarine). Median POP contents per portion size of cooked foods were 0.57 mg (range 0.05-1.11 mg) with control margarine versus 1.42 mg (range 0.08-20.5 mg) with PS-margarine. The oxidation rate of PS (ORP) was 0.50% (median) with the PS-margarine and 3.66% with the control margarine. Using the PS-margarine, microwave-cooked codfish had the lowest POP content, with 0.08 mg per portion, while shallow-fried potatoes had the highest POP content, 20.5 mg per portion. Median POP contents in cookies, muffins, banana bread, and sponge cake baked with the control or PS-margarine were 0.12 mg (range 0.11-0.21 mg) and 0.24 mg (range 0.19-0.60 mg) per portion, with a corresponding ORP of 1.38% and 0.06%, respectively. POP contents in all the cooked and baked foods did not exceed 20.5 mg per typical portion size. A wide variation in the distribution of individual POP among different foods existed, with 7-keto-PS and 5,6-epoxy-PS being the major oxidation products.

  19. Reduction of cholesterol absorption by dietary plant sterols and stanols in mice is independent of the Abcg5/8 transporter

    NARCIS (Netherlands)

    Plosch, Torsten; Kruit, Janine K.; Bloks, Vincent W.; Huijkman, Nicolette C. A.; Havinga, Rick; Duchateau, Guns S. M. J. E.; Lin, Yuguang; Kuipers, Folkert

    2006-01-01

    Dietary supplementation with plant sterols, stanols, and their esters reduces intestinal cholesterol absorption, thus lowering plasma LDL cholesterol concentration in humans. It was suggested that these beneficial effects are attributable in part to induction of genes involved in intestinal choleste

  20. Corn fiber oil lowers plasma cholesterol levels and increases cholesterol excretion greater than corn oil and similar to diets containing soy sterols and soy stanols in hamsters.

    Science.gov (United States)

    Wilson, T A; DeSimone, A P; Romano, C A; Nicolosi, R J

    2000-09-01

    The aims of this study were to compare the cholesterol-lowering properties of corn fiber oil (CFO) to corn oil (CO), whether the addition of soy stanols or soy sterols to CO at similar levels in CFO would increase CO's cholesterol-lowering properties, and the mechanism(s) of action of these dietary ingredients. Fifty male Golden Syrian hamsters were divided into 5 groups of 10 hamsters each, based on similar plasma total cholesterol (TC) levels. The first group of hamsters was fed a chow-based hypercholesterolemic diet containing either 5% coconut oil + 0.24% cholesterol (coconut oil), 5% CO, 5% CFO, 5% CO + 0.6% soy sterols (sterol), or 5% CO + 0.6% soy stanols (stanol) in place of the coconut oil for 4 weeks. The stanol diet significantly inhibited the elevation of plasma TC compared to all other dietary treatments. Also, the CFO and sterol diets significantly inhibited the elevation of plasma TC compared to the CO and coconut oil diets. The CFO, sterol, and stanol diets significantly inhibited the elevation of plasma non-high density lipoprotein cholesterol compared to the CO and coconut oil diets. The stanol diet significantly inhibited the elevation of plasma high density lipoprotein cholesterol (HDL-C) compared to all other dietary treatments. The sterol diet significantly inhibited the elevation of plasma HDL-C compared to the CO and coconut oil diets, whereas the CFO diet significantly inhibited the elevation of plasma HDL-C compared to the coconut oil diet only. No differences were observed between the CFO and CO for plasma HDL-C. There were no differences observed between groups for plasma triglycerides. The CO and CFO diets had significantly less hepatic TC compared to the coconut oil, sterol, and stanol diets. The CO and CFO diets had significantly less hepatic free cholesterol compared to the sterol and stanol diets but not compared to the coconut oil diet; whereas the coconut oil and sterol diets had significantly less hepatic free cholesterol

  1. Inhibition of Sterol Biosynthesis by 2-Isopropyl-4-dimethylamino-5-methylphenyl-1-piperidine Carboxylate Methyl Chloride in Tobacco and Rat Liver Preparations.

    Science.gov (United States)

    Douglas, T J; Paleg, L G

    1972-03-01

    2-Isopropyl-4-dimethylamino-5-methylphenyl-1-piperidine carboxylate methyl chloride, 90%, applied to rootless tobacco (Nicotiana tabacum cv. Samson) seedlings inhibits the incorporation of (14)C-mevalonate into sterols. Concomitantly, the retardant causes the accumulation of squalene-2,3-epoxide, an intermediate in sterol biosynthesis. The results with tobacco are identical to those produced by the retardant in cell-free rat liver preparations.

  2. Inoculation of the nonlegume Capsicum annuum L. with Rhizobium strains. 2. Changes in sterols, triterpenes, fatty acids, and volatile compounds.

    Science.gov (United States)

    Silva, Luís R; Azevedo, Jessica; Pereira, Maria J; Carro, Lorena; Velazquez, Encarna; Peix, Alvaro; Valentão, Patrícia; Andrade, Paula B

    2014-01-22

    Peppers (Capsicum spp.) are consumed worldwide, imparting flavor, aroma, and color to foods, additionally containing high concentrations of biofunctional compounds. This is the first report about the effect of the inoculation of two Rhizobium strains on sterols, triterpenes, fatty acids, and volatile compounds of leaves and fruits of pepper (Capsicum annuum L.) plants. Generally, inoculation with strain TVP08 led to the major changes, being observed a decrease of sterols and triterpenes and an increase of fatty acids, which are related to higher biomass, growth, and ripening of pepper fruits. The increase of volatile compounds may reflect the elicitation of plant defense after inoculation, since the content on methyl salicylate was significantly increased in inoculated material. The findings suggest that inoculation with Rhizobium strains may be employed to manipulate the content of interesting metabolites in pepper leaves and fruits, increasing potential health benefits and defense abilities of inoculated plants.

  3. Pregna-5,17(20)-dien-21-oyl amides affecting sterol and triglyceride biosynthesis in Hep G2 cells.

    Science.gov (United States)

    Stulov, Sergey V; Mankevich, Olga V; Dugin, Nikita O; Novikov, Roman A; Timofeev, Vladimir P; Misharin, Alexander Yu

    2013-04-01

    Synthesis of series [17(20)Z]- and [17(20)E]-pregna-5,17(20)-dien-21-oyl amides, containing polar substituents in amide moiety, based on rearrangement of 17α-bromo-21-iodo-3β-acetoxypregn-5-en-20-one caused by amines, is presented. The titled compounds were evaluated for their potency to regulate sterol and triglyceride biosynthesis in human hepatoma Hep G2 cells in comparison with 25-hydroxycholesterol. Three [17(20)E]-pregna-5,17(20)-dien-21-oyl amides at a concentrations of 5 μM inhibited sterol biosynthesis and stimulated triglyceride biosynthesis; their regulatory potency was dependent on the structure of amide moiety; the isomeric [17(20)Z]-pregna-5,17(20)-dien-21-oyl amides were inactive.

  4. The influence of amphotericin B on the molecular organization and structural properties of DPPC lipid membranes modified by sterols

    Science.gov (United States)

    Kamiński, Daniel M.; Pociecha, Damian; Górecka, Ewa; Gagoś, Mariusz

    2015-02-01

    In this work, we studied the influence of the polyene antibiotic amphotericin B (AmB) on dipalmitoylphosphatidylcholine (DPPC) multibilayers modified by cholesterol and ergosterol investigated by means of X-ray diffraction. The periodic structures related to AmB-DPPC-sterol complexes in multibilayers are completely created in temperatures above the main lipid phase transition. The differences between all observed multilayer structures are related to the thickness. Multibilayers composed of lipid and sterols have similar thickness of 51 Å. Addition of amphotericin B leads to creation of new periodic structures. Multibilayers composed of lipid-ergosterol-AmB have thickness of 44 Å which does not change with temperature. Multibilayers composed of lipid-cholesterol-AmB at 20 °C are 43 Å and gets thicker at 50 °C. Most probably this is caused by weaker van der Vaals cholesterol-amphotericin B interactions.

  5. Esterificación quimioselectiva de fitosteroles de madera mediante lipasas Chemoselective transesterification of wood steroles by lipases

    Directory of Open Access Journals (Sweden)

    Álvaro Gregorio

    2008-07-01

    estanol; enzima inmovilizadaThe chemoselective transesterification of wood sterols is a novel type application of lipases that is considered within a technological platform for the upgrading of black liquor from the Kraft pulping process. Wood sterols are a mixture of sterols and stanols (saturated sterols in which more than 90% is represented by β-sitosterol and β-sitostanol. Both products are oriented to different markets, representing the fractionation of the wood sterols a significant added value. Both substances are structurally similar which precludes its separation by physical operations, being its fractionation by chemoselective esterification with lipases a very appealing strategy. Several commercial lipases were evaluated in their capacity for the selective transesterification of stanols and two of them were selected: one immobilized and one non-supported. The process was optimized with the immobilized lipase obtaining more than 90% esterification of sterols with around 20% esterification of sterols, which satisfied the criterion of selectivity. The immobilized enzyme was however poorly stable because of protein desorption during the reaction; therefore, several strategies of immobilization of the non-supported lipase were developed, best results being obtained with butyl Sepabeads® as support. The selected biocatalyst was tested in the sequential batch reaction of transesterification, proving that the biocatalyst can be used for five sequential batches with very little loss of activity and insignificant reduction in conversion and productivity, which satisfies the profitability criterion of the process. Key words: Lipase; enzymatic transesterification; wood sterols; stanol esters; immobilized enzyme.

  6. A New Cytotoxic Sterol Produced By an Endophytic Fungus from Castaniopsis Fissa at the Couth China Sea Coast

    Institute of Scientific and Technical Information of China (English)

    Hou Jin LI; Yong Cheng LIN; L. L. P. VRIJMOED; E. B. G. JONES

    2004-01-01

    A new sterol,ergosta-8(9),22-diene-3,5,6,7-tetraol(3β,5α,6β,7α,22E)(A)together with three known sterols:3β,5α,6β-trihydroxyergosta-7,22-diene(B),3β-hydroxy-5α,8α-epidioxyer-gosta-6,22-diene(C)and ergosterol(D)were isolated from the mycelia of an unidentified endophytic fungus separated from Castaniopsis fissa(chestnut tree).Compound A exhibited potent selective cytotoxicity against Bel-7402,NCI4460 and L-02 cell lines with IC50values 8.445,5.03,13.621μg/mL,respectively.

  7. Sterol Composition and Biosynthetic Genes of Vitrella brassicaformis, a Recently Discovered Chromerid: Comparison to Chromera velia and Phylogenetic Relationship with Apicomplexan Parasites.

    Science.gov (United States)

    Khadka, Manoj; Salem, Mohamed; Leblond, Jeffrey D

    2015-01-01

    Vitrella brassicaformis is the second discovered species in the Chromerida, and first in the family Vitrellaceae. Chromera velia, the first discovered species, forms an independent photosynthetic lineage with V. brassicaformis, and both are closely related to peridinin-containing dinoflagellates and nonphotosynthetic apicomplexans; both also show phylogenetic closeness with red algal plastids. We have utilized gas chromatography/mass spectrometry to identify two free sterols, 24-ethylcholest-5-en-3β-ol, and a minor unknown sterol which appeared to be a C(28:4) compound. We have also used RNA Seq analysis to identify seven genes found in the nonmevalonate/methylerythritol pathway (MEP) for sterol biosynthesis. Subsequent genome analysis of V. brassicaformis showed the presence of two mevalonate (MVA) pathway genes, though the genes were not observed in the transcriptome analysis. Transcripts from four genes (dxr, ispf, ispd, and idi) were selected and translated into proteins to study the phylogenetic relationship of sterol biosynthesis in V. brassicaformis and C. velia to other groups of algae and apicomplexans. On the basis of our genomic and transcriptomic analyses, we hypothesize that the MEP pathway was the primary pathway that apicomplexans used for sterol biosynthesis before they lost their sterol biosynthesis ability, although contribution of the MVA pathway cannot be discounted.

  8. Development of a fast sample treatment for the analysis of free and bonded sterols in human serum by LC-MS.

    Science.gov (United States)

    Mendiara, Isabel; Domeño, Celia; Nerín, Cristina

    2012-12-01

    The analysis of sterols in biological fluids allows the clinical study of cholesterol related diseases. This research is focused on reducing the sample processing time of the determination of free and bonded sterols in human serum. Ten sterols were studied: cholesterol precursors (desmosterol, lanosterol, and cholestanol); phytosterols (stigmasterol, campesterol, sitosterol, and sitostanol) and oxysterols (7-α-hydroxy-4-cholesten-3-one, 24-hydroxycholesterol, and 27-hydroxycholesterol). Ultrasound assistance was used to diminish the reaction time during the alkaline hydrolysis for determining total sterols. Different retention mechanisms of solid-phase extraction were compared, two reversed-phase sorbents DSC-18 and polymeric Oasis-HLB and a novel zirconia-coated silica phase. DSC-18 and zirconia-coated silica were the most suitable sorbents to analyze these metabolites. The resulting extracts were analyzed by liquid chromatography coupled to mass spectrometry. The analytical parameters were determined and better values were observed with DSC-18 cartridges for most sterols. LOQ were in the low ng/mL level. Recoveries were in the range 85-99%. Average intermediate precision was 15%. Accuracy for both cartridges was more than 92%. Zirconia-coated silica showed better performance for the oxysterols, with recoveries around 90%. The procedure allows the determination of free and bonded sterol precursors, phytosterols, and oxysterols in human serum. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The response of the grape berry moth (Lobesia botrana) to a dietary phytopathogenic fungus (Botrytis cinerea): the significance of fungus sterols.

    Science.gov (United States)

    Mondy; Corio-Costet

    2000-12-01

    A Tortricidae (Lobesia botrana) has a mutualistic relationship with the fungus (Botrytis cinerea). In this study, we investigated the growth, survival, fecundity and amount of sterols and steroids in larvae of this vineyard pest reared on artificial diets containing mycelium (3%) or purified sterols (0.01%) of the phytopathogenic fungus. Two principal questions related to the physiological and biochemical basis of this mutualistic relationship were addressed: (1) how the fungus influences growth, survival, fecundity, sterol and steroid contents of the insect and (2) are fungal sterols involved in the biochemical basis of mutualism? The presence of fungus in the diet led to a decrease of total duration of larval development (mean gain 5.1-9.4 days compared to the total duration in control of 42.9 days), an increase in survival (mean gain 50-76.3%) and fecundity (gain of 94-102%). These positive effects of the fungus on the biology and physiology of the insect were directly correlated to the presence of fungal sterols in the diet. Fungal sterols are one of the biochemical basis of the mutualistic relationship between L. botrana and B. cinerea.

  10. A search for mosquito larvicidal compounds by blocking the sterol carrying protein, AeSCP-2, through computational screening and docking strategies

    Directory of Open Access Journals (Sweden)

    R Barani Kumar

    2010-01-01

    Full Text Available Background: Sterol is a very vital compound for most of the insects and mosquitoes to complete their life cycle. Unfortunately mosquitoes cannot synthesize the sterol, it depends on mammals for the same. Mosquitoes take the sterol from the plant decays during their larval stage in the form of phytosterol, which is then converted to cholesterol for further growth and reproduction. This conversion occurs with the help of the sterol carrier protein 2(SCP2. Methods: Mosquito populations are controlled by plant-based inhibitors, which inhibit sterol carrier protein (SCPI-Sterol carrier protein inhibitor activity. In this article, we explain the methods of inhibiting Aedes aegypti SCP2 by insilico methods including natural inhibitor selection and filtrations by virtual screening and interaction studies. Results: In this study protein-ligand interactions were carried out with various phytochemicals, as a result of virtual screening Alpha-mangostin and Panthenol were found to be good analogs, and were allowed to dock with the mosquito cholesterol carrier protein AeSCP-2. Conclusion: Computational selections of SCPIs are highly reliable and novel methods for discovering new and more effective compounds to control mosquitoes.

  11. Structural studies on meiosis-activating sterols and structurally related compounds : potential ligands of the FF-MAS receptor

    NARCIS (Netherlands)

    Boer, D.R.

    2001-01-01

    Meiosis Activating Sterols (MAS) are key regulatory factors in the meiotic cell cycle. Two compounds in this family, Follicular Fluid-MAS (FF-MAS or 4,4-dimethyl-5a-cholest-8,14,24-triene-3b-ol) and Testicular-MAS (T-MAS or 4,4-dimethyl-5a-cholest-8,14-diene-3b-ol), have been isolated and

  12. A Perspective on Free Radical Autoxidation: The Physical Organic Chemistry of Polyunsaturated Fatty Acid and Sterol Peroxidation

    OpenAIRE

    2013-01-01

    This Perspective describes advances from the author’s laboratory on the free radical reactions of organic compounds with molecular oxygen. Polyunsaturated fatty acids (PUFAs) and sterols are particularly prone to undergo radical chain oxidation and evidence suggests that this process, known as lipid peroxidation, occurs in vivo under a variety of conditions that are the result of an oxidative stress. Cyclic peroxides, hydroperoxides, and epoxy-alcohols are major products formed from peroxidat...

  13. Randomised controlled trial of use by hypercholesterolaemic patients of a vegetable oil sterol-enriched fat spread.

    Science.gov (United States)

    Neil, H A; Meijer, G W; Roe, L S

    2001-06-01

    Plant sterols may be a useful additive therapy in the treatment of hypercholesterolaemic patients. The purpose of this study was to determine the effect of a fat spread enriched with vegetable oil sterols on plasma lipid, lipoprotein and apolipoprotein concentrations. A randomised double blind placebo-controlled crossover trial with two consecutive periods of 8 weeks was conducted. 30 patients with heterozygous familial hypercholesterolaemia treated concurrently with an HMG-CoA reductase inhibitor (statin) and 32 patients with type IIa primary hypercholesterolaemia with a total cholesterol concentration >6.5 mmol/l not taking lipid-lowering drug therapy were recruited from a hospital lipid clinic. The active treatment was a fortified fat spread (25 g/day) providing 2.5 g of plant sterols. The control spread was indistinguishable in taste and appearance. Comparison at the end of the two 8-week trial periods showed a statistically significant reduction in total and LDL-cholesterol with use of the fortified spread but the results were confounded by a carry-over effect, which was partly explained by changes in the background diet. Because a carry-over effect was present, further analyses were restricted to the parallel arms of the first treatment period and were conducted on an intention to treat basis. After 4 weeks, LDL-cholesterol had decreased by 0.04 mmol/l ([0.8%] 95% confidence interval -0.44-0.37 NS) in the placebo group and decreased by -0.76 mmol/l ([15.0%] 95% CI -1.03--0.48, Pvegetable oil sterols reduces LDL-cholesterol by 10-15% with no difference in response between hypercholesterolaemic patients prescribed statins and those not taking lipid-lowering drug therapy.

  14. Expression of C-5 sterol desaturase from an edible mushroom in fisson yeast enhances its ethanol and thermotolerance.

    Science.gov (United States)

    Kamthan, Ayushi; Kamthan, Mohan; Datta, Asis

    2017-01-01

    Bioethanol is an environment friendly and renewable source of energy produced by the fermentation of agricultural raw material by a variety of microorganisms including yeast. Obtaining yeast strains that are tolerant to stresses like high levels of ethanol and high temperature is highly desirable as it reduces cost and increases yield during bioethanol production. Here, we report that heterologous expression of C-5 Sterol desaturase (FvC5SD)-an ergosterol biosynthesis enzyme from an edible mushroom Flammulina velutipes in fission yeast, not only imparts increased thermotolerance but also tolerance towards high ethanol concentration and low pH. This tolerance could be attributed to an increase of ≈1.5 fold in the level of ergosterol and oleic acid (C-18 unsaturated fatty acid) as analysed by gas chromatography- mass spectrometry. FvC5SD is a membrane localized iron binding enzyme that introduces double bond at C-5 position into the Δ7-sterol substrates to yield Δ5, 7- sterols as products. In F. velutipes, FvC5SD transcript was observed to be upregulated by ≈5 fold under low pH condition and by ≈ 9 folds and ≈5 fold at 40°C and 4°C respectively when compared to normal growth temperature of 23°C. Besides, susceptibility to cell wall inhibiting drugs like Congo red and Calcoflour white was also found to increase in FvC5SD expressing S. pombe strain. Alteration in membrane sterol and fatty acid composition could also lead to increase in susceptibility to cell wall inhibiting drugs. Thus, this study has immense industrial application and can be employed to ensure competitiveness of fermentation process.

  15. Hepatic entrapment of esterified cholesterol drives continual expansion of whole body sterol pool in lysosomal acid lipase-deficient mice.

    Science.gov (United States)

    Aqul, Amal; Lopez, Adam M; Posey, Kenneth S; Taylor, Anna M; Repa, Joyce J; Burns, Dennis K; Turley, Stephen D

    2014-10-15

    Cholesteryl ester storage disease (CESD) results from loss-of-function mutations in LIPA, the gene that encodes lysosomal acid lipase (LAL). Hepatomegaly and deposition of esterified cholesterol (EC) in multiple organs ensue. The present studies quantitated rates of synthesis, absorption, and disposition of cholesterol, and whole body cholesterol pool size in a mouse model of CESD. In 50-day-old lal(-/-) and matching lal(+/+) mice fed a low-cholesterol diet, whole animal cholesterol content equalled 210 and 50 mg, respectively, indicating that since birth the lal(-/-) mice sequestered cholesterol at an average rate of 3.2 mg·day(-1)·animal(-1). The proportion of the body sterol pool contained in the liver of the lal(-/-) mice was 64 vs. 6.3% in their lal(+/+) controls. EC concentrations in the liver, spleen, small intestine, and lungs of the lal(-/-) mice were elevated 100-, 35-, 15-, and 6-fold, respectively. In the lal(-/-) mice, whole liver cholesterol synthesis increased 10.2-fold, resulting in a 3.2-fold greater rate of whole animal sterol synthesis compared with their lal(+/+) controls. The rate of cholesterol synthesis in the lal(-/-) mice exceeded that in the lal(+/+) controls by 3.7 mg·day(-1)·animal(-1). Fractional cholesterol absorption and fecal bile acid excretion were unchanged in the lal(-/-) mice, but their rate of neutral sterol excretion was 59% higher than in their lal(+/+) controls. Thus, in this model, the continual expansion of the body sterol pool is driven by the synthesis of excess cholesterol, primarily in the liver. Despite the severity of their disease, the median life span of the lal(-/-) mice was 355 days.

  16. 甾醇酯微胶囊制备工艺研究%Research on preparation of sterol ester microcapsules

    Institute of Scientific and Technical Information of China (English)

    夏辉; 刘欣荣

    2012-01-01

    研究了喷雾干燥法制备微胶囊化甾醇酯的工艺。研究结果表明:微胶囊化甾醇酯的最优乳化条件为:复合乳化剂配比(单甘酯∶蔗糖酯)为1∶9;乳化剂用量0.75%;壁材用量20%;壁材比(变性淀粉∶麦芽糊精)为1∶5;芯材/壁材为0.5。喷雾干燥法制备甾醇酯微胶囊的最佳工艺参数为:进料温度50~60℃、均质压力50 MPa、进风温度180℃、出风温度80℃、喷雾压力180 KPa。在此工艺条件下微胶囊化效率可达77.8%。%The preparation of sterol esters microcapsules by spray drying was studied.The result showed that the optimum emulsification conditions of sterol esters microcapsule were the ratio of glycerol monoester to sucrose fatty acid ester 1∶ 9,emulsifier 0.75%,emulsion concentration 20%,the ratio of starch to maltodextrane1∶ 5,and the ratio of sterol esters to wall material was 0.5.The optimal parameters for preparing sterol esters microcapsules by spray drying were feed temperature 50~60 ℃,homogenizing pressure 50 MPa,temperatures of inlet wind and outlet wind 180 ℃ and 80 ℃,spray pressure 180 Kpa.The microencapsulating efficiency was 77.8% at these conditions.

  17. Cloning and expression of two sterol C-24 methyltransferase genes from upland cotton (Gossypium hirsuturm L.)

    Institute of Scientific and Technical Information of China (English)

    Ming Luo; Kunling Tan; Zhongyi Xiao; Mingyu Hu; Peng Liao; Kuijun Chen

    2008-01-01

    Brassinosteroids (BRs) are an important class of plant steroidal hormones that are essential in a wide variety of physiological processes. Two kinds of intermediates, sitosterol and campesterol, play a crucial role in cell elongation, cellulose biosynthesis, and accumulation. To illuminate the effects of sitosterol and campesterol on the development of cotton (Gossypium hirsuturm L.) fibers through screening cotton fiber EST database and contigging the candidate ESTs, two key genes GhSMT2-1 and GhSMT2-2 controlling the sitosterol biosynthesis were cloned from developing fibers of upland cotton cv. Xuzhou 142. The full length of GhSMT2-1 was 1, 151bp, including an 8bp 5'-untranslated region (UTR), a 1, 086bp open reading frame (ORF), and a 57bp 3'-UTR. GhSMT2-1 gene encoded a polypeptide of 361 amino acid residues with a predicted molecular mass of 40kDa. The full length of GhSMT2-2 was 1, 166bp, including an 18bp 5'-UTR, a 1, 086bp ORF, and a 62bp 3'-UTR. GhSMT2-2 gene encoded a polypeptide of 361 amino acid residues with a predicted molecular mass of 40kDa. The two deduced amino acid sequences had high homology with the SMT2 from Arabidopsis thaliana and Nicotiana tabacum. Furthermore, the typical conserved structures characterized by the sterol C-24 methyltransferase, such as region I (LDVGCGVGGPIVIRAI), region Ⅱ (IEATCHAP), and region Ⅲ (YEWGWGQSFHF), were present in both deduced proteins. Southern blotting analysis indicated that GhSMT2-1 or GhSMT2-2 was a single copy in upland cotton genome. Quantitative real-time RT-PCR analysis revealed that the highest expression levels of both genes were detected in 10 DPA (day post anthesis) fibers, while the lowest levels were observed in cotyledon and leaves. The expression level of GhSMT2-1 was 10 times higher than that of GhSMT2-2 in all the organs and tissues detected. These results indicate that the homologue of sterol C-24 methyltransferase gene was cloned from upland cotton and both GhSMT2 genes play a crucial

  18. Sterol structure determines the separation of phases and the curvature of the liquid-ordered phase in model membranes.

    Science.gov (United States)

    Bacia, Kirsten; Schwille, Petra; Kurzchalia, Teymuras

    2005-03-01

    The existence of lipid rafts in biological membranes in vivo is still debated. In contrast, the formation of domains in model systems has been well documented. In giant unilamellar vesicles (GUVs) prepared from ternary mixtures of dioleoyl-phosphatidylcholine/sphingomyelin/cholesterol, a clear separation of liquid-disordered and sphingomyelin-enriched, liquid-ordered phases could be observed. This phase separation can lead to the fission of the liquid-ordered phase from the vesicle. Here we show that in cholesterol-containing GUVs, the phase separation can involve dynamic redistribution of lipids from one phase into another as a result of a cross-linking perturbation. We found that the molecular structure of a sterol used for the preparation of GUVs determines (i) its ability to induce phase separation and (ii) the curvature (positive or negative) of the formed liquid-ordered phase. As a consequence, the latter can pinch off to the outside or inside of the vesicle. Remarkably, some mixtures of sterols induce liquid-ordered domains exhibiting both positive and negative curvature, which can lead to a new type of budding behavior in GUVs. Our findings could have implications for the role of sterols in various cell-biological processes such as budding of secretory vesicles, endocytosis, or formation of multivesicular bodies.

  19. Secretion and Signaling Activities of Lipoprotein-Associated Hedgehog and Non-Sterol-Modified Hedgehog in Flies and Mammals

    Science.gov (United States)

    Kumari, Veena; Ehrhart-Bornstein, Monika; Bornstein, Stefan R.; Eaton, Suzanne

    2013-01-01

    Hedgehog (Hh) proteins control animal development and tissue homeostasis. They activate gene expression by regulating processing, stability, and activation of Gli/Cubitus interruptus (Ci) transcription factors. Hh proteins are secreted and spread through tissue, despite becoming covalently linked to sterol during processing. Multiple mechanisms have been proposed to release Hh proteins in distinct forms; in Drosophila, lipoproteins facilitate long-range Hh mobilization but also contain lipids that repress the pathway. Here, we show that mammalian lipoproteins have conserved roles in Sonic Hedgehog (Shh) release and pathway repression. We demonstrate that lipoprotein-associated forms of Hh and Shh specifically block lipoprotein-mediated pathway inhibition. We also identify a second conserved release form that is not sterol-modified and can be released independently of lipoproteins (Hh-N*/Shh-N*). Lipoprotein-associated Hh/Shh and Hh-N*/Shh-N* have complementary and synergistic functions. In Drosophila wing imaginal discs, lipoprotein-associated Hh increases the amount of full-length Ci, but is insufficient for target gene activation. However, small amounts of non-sterol-modified Hh synergize with lipoprotein-associated Hh to fully activate the pathway and allow target gene expression. The existence of Hh secretion forms with distinct signaling activities suggests a novel mechanism for generating a diversity of Hh responses. PMID:23554573

  20. Lipid profile and non-cholesterol sterols in obese women's serum after supplementing with plant stanol ester.

    Science.gov (United States)

    Stelmach-Mardas, Marta; Walkowiak, Jarosław; Zagrodzki, Paweł; Grygiel-Górniak, Bogna; Przysławski, Juliusz

    2014-01-01

    The aim of this study was to assess the influence of increased plant stanol ester intake on lipid profile and serum ratio of non-cholesterol sterols to cholesterol in obese women (50 years of age) with dyslipidemia. 90 females were assigned into 2 treatment groups: For a period of 4 weeks, group 1 was receiving a yoghurt, enriched with 2 g of plant stanol ester (PS group), and group 2 was receiving a yoghurt drink without extra stanols. Anthropometric measurements included body height and weight. Lipid profile was determined by commercially available enzymatic methods. Serum non-cholesterol sterols and stanols concentrations were quantitated by gas chromatography. The study was single-blind and placebo-controlled. The yoghurt drink enriched with plant stanol ester significantly reduced serum total cholesterol, LDL cholesterol, and non-HDL cholesterol levels (p sterols to cholesterol: campesterol, sitosterol, sitostanol, and avenasterol. Plant stanol esters influence the concentration of total cholesterol, particularly LDL cholesterol. This effect seems to be related to the reduced dietary cholesterol absorption. © 2014 S. Karger GmbH, Freiburg.

  1. A comprehensive method for extraction and quantitative analysis of sterols and secosteroids from human plasma[S

    Science.gov (United States)

    McDonald, Jeffrey G.; Smith, Daniel D.; Stiles, Ashlee R.; Russell, David W.

    2012-01-01

    We describe the development of a method for the extraction and analysis of 62 sterols, oxysterols, and secosteroids from human plasma using a combination of HPLC-MS and GC-MS. Deuterated standards are added to 200 μl of human plasma. Bulk lipids are extracted with methanol:dichloromethane, the sample is hydrolyzed using a novel procedure, and sterols and secosteroids are isolated using solid-phase extraction (SPE). Compounds are resolved on C18 core-shell HPLC columns and by GC. Sterols and oxysterols are measured using triple quadrupole mass spectrometers, and lathosterol is measured using GC-MS. Detection for each compound measured by HPLC-MS was ∪ 1 ng/ml of plasma. Extraction efficiency was between 85 and 110%; day-to-day variability showed a relative standard error of <10%. Numerous oxysterols were detected, including the side chain oxysterols 22-, 24-, 25-, and 27-hydroxycholesterol, as well as ring-structure oxysterols 7α- and 4β-hydroxycholesterol. Intermediates from the cholesterol biosynthetic pathway were also detected, including zymosterol, desmosterol, and lanosterol. This method also allowed the quantification of six secosteroids, including the 25-hydroxylated species of vitamins D2 and D3. Application of this method to plasma samples revealed that at least 50 samples could be extracted in a routine day. PMID:22517925

  2. Genetic variation in plant CYP51s confers resistance against voriconazole, a novel inhibitor of brassinosteroid-dependent sterol biosynthesis.

    Directory of Open Access Journals (Sweden)

    Wilfried Rozhon

    Full Text Available Brassinosteroids (BRs are plant steroid hormones with structural similarity to mammalian sex steroids and ecdysteroids from insects. The BRs are synthesized from sterols and are essential regulators of cell division, cell elongation and cell differentiation. In this work we show that voriconazole, an antifungal therapeutic drug used in human and veterinary medicine, severely impairs plant growth by inhibiting sterol-14α-demethylation and thereby interfering with BR production. The plant growth regulatory properties of voriconazole and related triazoles were identified in a screen for compounds with the ability to alter BR homeostasis. Voriconazole suppressed growth of the model plant Arabidopsis thaliana and of a wide range of both monocotyledonous and dicotyledonous plants. We uncover that voriconazole toxicity in plants is a result of a deficiency in BRs that stems from an inhibition of the cytochrome P450 CYP51, which catalyzes a step of BR-dependent sterol biosynthesis. Interestingly, we found that the woodland strawberry Fragaria vesca, a member of the Rosaceae, is naturally voriconazole resistant and that this resistance is conferred by the specific CYP51 variant of F. vesca. The potential of voriconazole as a novel tool for plant research is discussed.

  3. Feedback regulation of cholesterol synthesis:sterol-accelerated ubiquitination and degradation of HMG CoA reductase

    Institute of Scientific and Technical Information of China (English)

    Russell A DeBose-Boyd

    2008-01-01

    3Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase produces mevalonate,an important intermediate in the synthesis of cholesterol and essential nonsterol isoprenoids.The reductase is subject to an exorbitant amount of feedback control through multiple mechanisms that are mediated by sterol and nonsterol end-products of mevalonate metabolism.Here,Ⅰwill discuss recent advances that shed light on one mechanism for control of reductase,which involves rapid degradation of the enzyme.Accumulation of certain sterols triggers binding of reductase to endoplasmic reticulum (ER) membrane proteins called Insig-1 and Insig-2.Reductase-Insig binding results in recruitment of a membrane-associated ubiquitin ligase called gp78,which initiates ubiquitination of reductase.This ubiquitination is an obligatory reaction for recognition and degradation of reductase from ER membranes by cytosolic 26S proteasomes.Thus,sterol-accelerated degradation of reductase represents an example of how a general cellular process (ER-associated degradation) is used to control an important metabolic pathway (cholesterol synthesis).

  4. [Determination of β-sitosterol and total sterols content and antioxidant activity of oil in acai (Euterpe oleracea)].

    Science.gov (United States)

    He, Cheng; Li, Wei; Zhang, Jian-Jun; Qu, Sheng-Sheng; Li, Jia-Jing; Wang, Lin-Yuan

    2014-12-01

    In order to establish a method for the determination of the sterols of the oil in the freeze-dried acai (Euterpe oleracea Mart.) and to evaluate its antioxidant activities, a saponification/extraction procedure and high performance liquid chromatography (HPLC) analysis method were developed and validated for the analysis of phytosterols in PEE (Petroleum ether extract). Separation was achieved on a Purosper STAR LP C18 column with a binary, gradient solvent system of acetonitrile and isopropanol. Evaporative light scattering detection (ELSD) was used to quantify β-sitosterol and the total sterols. Peak identification was verified by retention times and spikes with external standards. Standard curves were constructed (r = 0.999 2) to allow for sample quantification. Recovery of the saponification and extraction was demonstrated via analysis of spiked samples. The highest content of total sterols is β-sitosterol. The antioxidant activities of the extracts were evaluated using the total oxyradical scavenging capacity assay (TOSC assay). The result showed that the PEE exhibited significant antioxidant properties, sample concentration and the antioxidant capacity had a certain relevance.

  5. Determination of fatty acid, tocopherol and phyto sterol contents of the oils of various poppy (Papaver somniferum L.) seeds.

    Energy Technology Data Exchange (ETDEWEB)

    Enric, H.; Tekin, A.; Musa Ozcan, M.

    2009-07-01

    The fatty acid, tocopherol and sterol contents of the oils of several poppy seeds were investigated. The main fatty acids in poppy seed oils were linoleic (687.6-739.2 g kg{sup -}1), oleic (141.3-192.8 g kg{sup -}1) and palmitic (76.8-92.8 g kg{sup -}1). The oils contained an appreciable amount of {gamma}-tocopherol (195.37-280.85 mg kg{sup -}1), with a mean value of 261.31 mg kg-1 and {alpha}-tocopherol (21.99-45.83 mg kg{sup -}1), with a mean value of 33.03 mg kg{sup -}1. The concentrations of total sterol ranged from 1099.84 mg kg{sup -}1 (K.pembe) to 4816.10 mg kg-1 (2. sinif beyaz), with a mean value of 2916.20 mg kg{sup -}1. The major sterols were {beta}-sitosterol, ranging from 663.91 to 3244.39 mg kg{sup -}1; campesterol, ranging from 228.59 to 736.50 mg kg{sup -}1; and {delta}{sup 5}-avenasterol, ranging from 103.90 to 425.02 mg kg{sup -}1. The studied varieties of poppy seeds from Turkey were found to be a potential source of valuable oil. (Author) 31 refs.

  6. Fluorescence antibunching microscopy

    CERN Document Server

    Schwartz, Osip

    2011-01-01

    Breaking the diffraction limit in microscopy by utilizing quantum properties of light has been the goal of intense research in the recent years. We propose a quantum superresolution technique based on non-classical emission statistics of fluorescent markers, routinely used as contrast labels for bio-imaging. The technique can be readily implemented using standard fluorescence microscopy equipment.

  7. Fluorescence of atopic allergens

    NARCIS (Netherlands)

    Berrens, L.

    1967-01-01

    Purified atopic allergens have been found to emit flue fluorescence upon irradiation with ultraviolet light of 365 mμ wavelength. The maximum of fluorescence is in the region 445–490 mμ and the intensity is of the same order of magnitude for different atopic allergens. Synthetic model compounds, inc

  8. Fluorescent Lamp Replacement Study

    Science.gov (United States)

    2017-07-01

    Light-emitting diode, LED, lighting, fluorescent, waste reduction, energy conservation, net zero , mercury 16. SECURITY CLASSIFICATION OF: 17. LIMITATION...Center (ATC) to assess the benefits of converting fluorescent tube lighting to light-emitting diode (LED) technology. The report documents the waste ...1-15 SECTION 2. SUBTESTS 2.1 HAZARDOUS WASTE REDUCTION

  9. LEDs for fluorescence microscopy

    NARCIS (Netherlands)

    Young, I.T.; Garini, Y.; Dietrich, H.R.C.; Van Oel, W.; Liqui Lung, G.

    2004-01-01

    Traditional light sources for fluorescence microscopy have been mercury lamps, xenon lamps, and lasers. These sources have been essential in the development of fluorescence microscopy but each can have serious disadvantages: lack of near monochromaticity, heat generation, cost, lifetime of the light

  10. Sterol regulatory element binding transcription factor 1 (SREBF1) polymorphism and milk fatty acid composition.

    Science.gov (United States)

    Nafikov, R A; Schoonmaker, J P; Korn, K T; Noack, K; Garrick, D J; Koehler, K J; Minick-Bormann, J; Reecy, J M; Spurlock, D E; Beitz, D C

    2013-04-01

    Milk is known to contain high concentrations of saturated fatty acids-such as palmitic (16:0), myristic (14:0), and lauric (12:0) acids-that can raise plasma cholesterol in humans, making their presence in milk undesirable. The main objective of our candidate gene study was to develop genetic markers that can be used to improve the healthfulness of bovine milk. The sterol regulatory element binding transcription factor 1 (SREBF1) known to regulate the transcription of lipogenic genes together with SREBF chaperone and insulin induced gene 1 were the candidate genes. The results showed significant association of the overall SREBF1 haplotypes with milk production and variations in lauric (12:0) and myristic (14:0) acid concentrations in milk. Haplotype H1 of SREBF1 was the most desirable to improve milk healthfulness because it was significantly associated with lower lauric (12:0) and myristic (14:0) acid concentrations compared with haplotype H3 of SREBF1, and lower lauric acid (12:0) concentration compared with haplotype H2 of SREBF1. Haplotype H1 of SREBF1, however, was significantly associated with lower milk production compared with haplotype H3 of SREBF1. We did not detect any significant associations between genetic polymorphisms in insulin induced gene 1 (INSIG1) and SREBF chaperone and milk fatty acid composition. In conclusion, genetic polymorphisms in SREBF1 can be used to develop genetic tools for the selection of animals producing milk with healthier fatty acid composition.

  11. Presence of methyl sterol and bacteriohopanepolyol in an outer-membrane preparation from Methylococcus capsulatus (Bath)

    Science.gov (United States)

    Jahnke, Linda L.; Stan-Lotter, Helga; Kato, Katharine; Hochstein, Lawrence I.

    1992-01-01

    Cytoplasmic/intracytoplasmic and outer membrane preparations of Methylococcus capsulatus (Bath) were isolated by sucrose density gradient centrifugation of a total membrane fraction prepared by disruption using a French pressure cell. The cytoplasmic and/or intracytoplasmic membrane fraction consisted of two distinct bands, Ia and Ib (buoyant densities 1.16 and 1.18 g ml (exp -1), respectively) that together contained 57% of the protein, 68% of the phospholipid, 73% of the ubiquinone and 89% of the CN-sensitive NADH oxidase activity. The only apparent difference between these two cytoplasmic bands was a much higher phospholipid content for Ia. The outer membrane fraction (buoyant density 1.23-1.24 g ml (exp -1)) contained 60% of the lipopolysaccharide-associated, beta-hydroxypalmitic acid, 74% of the methylsterol, and 66% of the bacteriohopanepolyol (BHP); phospholipid to methyl sterol or BHP ratios were 6:1. Methanol dehydrogenase activity and a c-type cytochrome were also present in this outer membrane fraction. Phospholipase A activity was present in borh the cytoplasmic membrane and outer membrane fractions. The unique distribution of cyclic triterpenes may reflect a specific role in conferring outer membrane stability in this methanotrophic bacterium.

  12. Polyoxygenated sterols from the South China Sea soft coral Sinularia sp.

    Science.gov (United States)

    Li, Rui; Shao, Chang-Lun; Qi, Xin; Li, Xiu-Bao; Li, Jing; Sun, Ling-Ling; Wang, Chang-Yun

    2012-07-01

    Chemical investigation of the ethanol extract of soft coral Sinularia sp. collected from the South China Sea led to the isolation of three new polyoxygenated sterols, (3S,23R,24S)-ergost-5-ene-3β,23α,25-triol (1), (24S)-ergostane-6-acetate-3β,5α,6β,25-tetraol (2), (24S)-ergostane-6-acetate-3β,6β,12β,25-tetraol (3) together with three known ones (4-6). The structures, including relative configurations of the new compounds (1-3), were elucidated by detailed analysis of spectroscopic data (IR, UV, NMR, MS) and by comparison with related reported compounds. The absolute configuration of 1 was further determined by modified Mosher's method. Compound 5 exhibited moderate cytotoxicity against K562 cell line with an IC(50) value of 3.18 μM, but also displayed strong lethality toward the brine shrimp Artemia salina with a LC(50) value of 0.96 μM.

  13. New sterols with anti-inflammatory potentials against cyclooxygenase-2 and 5-lipoxygenase from Paphia malabarica.

    Science.gov (United States)

    Joy, Minju; Chakraborty, Kajal; Raola, Vamshi Krishna

    2017-06-01

    Marine bivalves occupy a leading share in the total edible molluscs at the coastline regions of south-eastern Asia, and are found to possess significant nutritional and biological potential. Various in vitro evaluation (antioxidant and anti-inflammatory) guided purification of ethyl acetate-methanol (EtOAc-MeOH) extract of bivalve clam, Paphia malabarica characterised two new sterol derivatives as 23-gem-dimethylcholesta-5-en-3β-ol (1) and (22E)-24(1),24(2)-methyldihomocholest-5,22-dien-3β-ol (2) collected from the south-west coast of Arabian Sea. Their structures were unambiguously assigned on the basis of 1D, 2D NMR spectroscopy and mass spectrometry. The antioxidant and anti-inflammatory activities of 2 as determined by DPPH/ABTS(+) radical scavenging and anti-cyclooxygenase-2/5-lipoxygenase assays were significantly greater (IC50  1 mg/mL). Structure-activity relationship analysis revealed that the bioactivities of these compounds were directly proportional to the electronic and lipophilic parameters. This is the first report of the occurrence and characterisation of 23-gem-dimethyl-3β-hydroxy-Δ(5)-cholestane nucleus and C-30 dihomosterol from marine organisms.

  14. The in-process removal of sterol glycosides by ultrafiltration in biodiesel production

    Directory of Open Access Journals (Sweden)

    André Y. Tremblay

    2017-03-01

    Full Text Available Minor components found in biodiesel can affect its stability and cold flow properties. Without extensive post treatments, trace compounds such as sterol glycosides (SG can remain at unacceptable levels in finished biodiesel fuels. This study proposes to remove SG from reacted Fatty Acid Methyl Ester (FAME mixtures using ultrafiltration. Degummed soybean oil was transesterified using methanol and a catalyst (sodium methoxide. The mixtures were immediately ultrafiltered after the reaction and the FAMEs from the retentate and permeate were analyzed for SG. The highest separation for SG (86 % was obtained when the reaction conditions were 0.7 wt.% catalyst and 4:1 MeOH:Oil ratio. The lowest separation (0% was observed at 0.3 wt.% catalyst and 4:1 MeOH:Oil ratio. The higher separations were explained by the deprotonation of the hydroxyl groups on SG. This decreased the solubility of SG in the reacted FAME phase. The separation was lowest, when unreacted oil along with monoacylglycerides (MG and diacylglycerides (DG solubilized SG in the reacted mixture. The separation was also low when high methanol to oil ratios were used in the transesterification. The lowest concentration of SG measured in FAMEs treated by ultrafiltration was 3.4 ppm. The results indicate that ultrafiltration is an effective method to remove SG from soybean FAMEs.

  15. Sterols from the red algae, Gracilaria salicornia and Hypnea flagelliformis, from Persian Gulf

    Science.gov (United States)

    Nasir, Masoumeh; Saeidnia, Soodabeh; Mashinchian-Moradi, Ali; Gohari, Ahmad R.

    2011-01-01

    Context: Two of the important algae from Persian Gulf are Gracilaria salicornia and Hypnea flageliformis (Rhodophyta). Antibacterial, antifungal, and cytotoxic effects of the mentioned algae have been presented in the previous studies. Aim: In this study, the isolation and structural elucidation of the sterols from these algae are reported. Materials and Methods: The separation and purification of the compounds were carried out with silica gel, sephadex LH20 column chromatography (CC) and HPLC to obtain six pure compounds 1-6. The structural elucidation of the constituents was based on the data obtained from H-NMR,13C-NMR, HMBC, HSQC, DEPT, and EI-MS. Results: The isolated compounds from G. salicornia were identified as 22-dehydrocholesterol (1), cholesterol (2), oleic acid (3), and stigmasterol (4), and the isolated constituents from H. flagelliformis were identified as 22-dehydrocholesterol (1), cholesterol (2), oleic acid (3), cholesterol oleate (5), and (22E)-cholesta-5,22-dien-3β-ol-7-one (6) based on the spectral data compared to those reported in the literature. Conclusion: Red algae are enriched with cholesterol polysaccharides. We first reported the presence of cholesteryl oleate and (22E)-cholesta-5,22-dien-3β-ol-7-one in H. flagelliformis. PMID:21716930

  16. Sterols from the red algae, Gracilaria salicornia and Hypnea flagelliformis, from Persian Gulf

    Directory of Open Access Journals (Sweden)

    Masoumeh Nasiri

    2011-01-01

    Full Text Available Context: Two of the important algae from Persian Gulf are Gracilaria salicornia and Hypnea flageliformis (Rhodophyta. Antibacterial, antifungal, and cytotoxic effects of the mentioned algae have been presented in the previous studies. Aim: In this study, the isolation and structural elucidation of the sterols from these algae are reported. Materials and Methods: The separation and purification of the compounds were carried out with silica gel, sephadex LH 20 column chromatography (CC and HPLC to obtain six pure compounds 1-6 . The structural elucidation of the constituents was based on the data obtained from H-NMR, 13 C-NMR, HMBC, HSQC, DEPT, and EI-MS. Results: The isolated compounds from G. salicornia were identified as 22-dehydrocholesterol (1, cholesterol (2, oleic acid (3, and stigmasterol (4, and the isolated constituents from H. flagelliformis were identified as 22-dehydrocholesterol (1, cholesterol (2, oleic acid (3, cholesterol oleate (5, and (22E-cholesta-5,22-dien-3β-ol-7-one (6 based on the spectral data compared to those reported in the literature. Conclusion: Red algae are enriched with cholesterol polysaccharides. We first reported the presence of cholesteryl oleate and (22E-cholesta-5,22-dien-3b-ol-7-one in H. flagelliformis.

  17. The IDOL–UBE2D complex mediates sterol-dependent degradation of the LDL receptor

    Science.gov (United States)

    Zhang, Li; Fairall, Louise; Goult, Benjamin T.; Calkin, Anna C.; Hong, Cynthia; Millard, Christopher J.; Tontonoz, Peter; Schwabe, John W.R.

    2011-01-01

    We previously identified the E3 ubiquitin ligase IDOL as a sterol-dependent regulator of the LDL receptor (LDLR). The molecular pathway underlying IDOL action, however, remains to be determined. Here we report the identification and biochemical and structural characterization of an E2–E3 ubiquitin ligase complex for LDLR degradation. We identified the UBE2D family (UBE2D1–4) as E2 partners for IDOL that support both autoubiquitination and IDOL-dependent ubiquitination of the LDLR in a cell-free system. NMR chemical shift mapping and a 2.1 Å crystal structure of the IDOL RING domain–UBE2D1 complex revealed key interactions between the dimeric IDOL protein and the E2 enzyme. Analysis of the IDOL–UBE2D1 interface also defined the stereochemical basis for the selectivity of IDOL for UBE2Ds over other E2 ligases. Structure-based mutations that inhibit IDOL dimerization or IDOL–UBE2D interaction block IDOL-dependent LDLR ubiquitination and degradation. Furthermore, expression of a dominant-negative UBE2D enzyme inhibits the ability of IDOL to degrade the LDLR in cells. These results identify the IDOL–UBE2D complex as an important determinant of LDLR activity, and provide insight into molecular mechanisms underlying the regulation of cholesterol uptake. PMID:21685362

  18. Fluconazole Binding and Sterol Demethylation in Three CYP51 Isoforms Indicate Differences in Active Site Topology

    Energy Technology Data Exchange (ETDEWEB)

    Bellamine, A.; Lepesheva, Galina I.; Waterman, Mike (Vanderbilt)

    2010-11-16

    14{alpha}-Demethylase (CYP51) is a key enzyme in all sterol biosynthetic pathways (animals, fungi, plants, protists, and some bacteria), catalyzing the removal of the C-14 methyl group following cyclization of squalene. Based on mutations found in CYP51 genes from Candida albicans azole-resistant isolates obtained after fluconazole treatment of fungal infections, and using site-directed mutagenesis, we have found that fluconazole binding and substrate metabolism vary among three different CYP51 isoforms: human, fungal, and mycobacterial. In C. albicans, the Y132H mutant from isolates shows no effect on fluconazole binding, whereas the F145L mutant results in a 5-fold increase in its IC{sub 50} for fluconazole, suggesting that F145 (conserved only in fungal 14{alpha}-demethylases) interacts with this azole. In C. albicans, F145L accounts, in part, for the difference in fluconazole sensitivity reported between mammals and fungi, providing a basis for treatment of fungal infections. The C. albicans Y132H and human Y145H CYP51 mutants show essentially no effect on substrate metabolism, but the Mycobacterium tuberculosis F89H CYP51 mutant loses both its substrate binding and metabolism. Because these three residues align in the three isoforms, the results indicate that their active sites contain important structural differences, and further emphasize that fluconazole and substrate binding are uncoupled properties.

  19. Presence of methyl sterol and bacteriohopanepolyol in an outer-membrane preparation from Methylococcus capsulatus (Bath)

    Science.gov (United States)

    Jahnke, Linda L.; Stan-Lotter, Helga; Kato, Katharine; Hochstein, Lawrence I.

    1992-01-01

    Cytoplasmic/intracytoplasmic and outer membrane preparations of Methylococcus capsulatus (Bath) were isolated by sucrose density gradient centrifugation of a total membrane fraction prepared by disruption using a French pressure cell. The cytoplasmic and/or intracytoplasmic membrane fraction consisted of two distinct bands, Ia and Ib (buoyant densities 1.16 and 1.18 g ml (exp -1), respectively) that together contained 57% of the protein, 68% of the phospholipid, 73% of the ubiquinone and 89% of the CN-sensitive NADH oxidase activity. The only apparent difference between these two cytoplasmic bands was a much higher phospholipid content for Ia. The outer membrane fraction (buoyant density 1.23-1.24 g ml (exp -1)) contained 60% of the lipopolysaccharide-associated, beta-hydroxypalmitic acid, 74% of the methylsterol, and 66% of the bacteriohopanepolyol (BHP); phospholipid to methyl sterol or BHP ratios were 6:1. Methanol dehydrogenase activity and a c-type cytochrome were also present in this outer membrane fraction. Phospholipase A activity was present in borh the cytoplasmic membrane and outer membrane fractions. The unique distribution of cyclic triterpenes may reflect a specific role in conferring outer membrane stability in this methanotrophic bacterium.

  20. Fluorescence and Spectral Imaging

    Directory of Open Access Journals (Sweden)

    Ralph S. DaCosta

    2007-01-01

    Full Text Available Early identification of dysplasia remains a critical goal for diagnostic endoscopy since early discovery directly improves patient survival because it allows endoscopic or surgical intervention with disease localized without lymph node involvement. Clinical studies have successfully used tissue autofluorescence with conventional white light endoscopy and biopsy for detecting adenomatous colonic polyps, differentiating benign hyperplastic from adenomas with acceptable sensitivity and specificity. In Barrett's esophagus, the detection of dysplasia remains problematic because of background inflammation, whereas in the squamous esophagus, autofluorescence imaging appears to be more dependable. Point fluorescence spectroscopy, although playing a crucial role in the pioneering mechanistic development of fluorescence endoscopic imaging, does not seem to have a current function in endoscopy because of its nontargeted sampling and suboptimal sensitivity and specificity. Other point spectroscopic modalities, such as Raman spectroscopy and elastic light scattering, continue to be evaluated in clinical studies, but still suffer the significant disadvantages of being random and nonimaging. A recent addition to the fluorescence endoscopic imaging arsenal is the use of confocal fluorescence endomicroscopy, which provides real-time optical biopsy for the first time. To improve detection of dysplasia in the gastrointestinal tract, a new and exciting development has been the use of exogenous fluorescence contrast probes that specifically target a variety of disease-related cellular biomarkers using conventional fluorescent dyes and novel potent fluorescent nanocrystals (i.e., quantum dots. This is an area of great promise, but still in its infancy, and preclinical studies are currently under way.

  1. Distribution characteristics of sterols in surface sediment of Dalian Bay%大连湾表层沉积物中甾醇的分布特征

    Institute of Scientific and Technical Information of China (English)

    冀平; 赵元凤; 徐恒振; 王洪艳; 姚子伟; 马新东

    2013-01-01

    11 sterols in the surface sediment samples in Dalian Bay were determined by GC/MS,and the distribution characteristics at 17 stations in this area were discussed.The results show that the total concentration range was (0 ~ 6.833) × 10-6,the sterols range was (1.627 ~34.617) × 10-6.The distribution appeared that the concentration of total sterols around the sewage ouffall was higher than that far away from the outfall.The main kinds of sterols were C27 sterols and C29 sterols and the source of sterols was a large number of domestic sewage.%采用气相色谱/质谱对大连湾表层沉积物中11种甾醇进行了监测,探讨了大连湾17个站位的表层沉积物中甾醇的分布特征.结果表明,大连湾17个站位的表层沉积物中11种甾醇的含量范围为1.627×10-6~34.617×10-6;甾醇分布呈现出近岸区高于离岸海区,近排污口区高于远排污口区的态势;甾醇种类主要为C27甾醇和C29甾醇;其来源主要是大量生活污水的输入.

  2. New method to determine free sterols/oxysterols in food matrices using gas chromatography and ion trap mass spectrometry (GC-IT-MS).

    Science.gov (United States)

    Szterk, Arkadiusz; Pakuła, Lucyna

    2016-05-15

    Sterols/oxysterols in food may be free or bound i.e. esterified with fatty acids. Methods commonly applied to determine those compounds in such matrices (based on various analytical techniques) usually start with hydrolysis of the food lipid fraction, which means that the results are no good indication of concentration of free sterols/oxysterols only. But only free oxysterols are proatherogenic factors, bound ones are not. There are some published methods selectively sensitive to free oxysterols only, but they are capable to determine only a few compounds and feature very low recovery rates. The aim of this work was to develop a method to determine various free (non-esterified) sterols/oxysterols in various food matrices. The developed method is based on the GC-IT-MS technique used in the chemical ionization mode. It was applied to determine 16 different free sterols/oxysterols in egg powder, cheese, butter, milk and salami. Fat extracted from the given matrix is purified on a specially prepared silica-gel bed to separate the sterol fraction from the oxysterol one. Sterols are silylated using N,O-bis(trimethylsilyl)trifluoroacetamide and trimethylchlorosilane BSTFA:TMCS, then GC-IT-MS analysed. The method features high recovery rates (75-95%), high reproducibility (RSD<20%), and sensitivity within the 0.01-0.3 mg 100 g(-1) range, depending on the analysed compound. The method is ideally suited for determination of free sterols/oxysterols. Besides, should total concentration of both free and bound forms be of interest, food lipids may be transesterificated before the silica-gel bed purification step.

  3. Highly thermostable fluorescent proteins

    Science.gov (United States)

    Bradbury, Andrew M [Santa Fe, NM; Waldo, Geoffrey S [Santa Fe, NM; Kiss, Csaba [Los Alamos, NM

    2012-05-01

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  4. Highly thermostable fluorescent proteins

    Science.gov (United States)

    Bradbury, Andrew M.; Waldo, Geoffrey S.; Kiss, Csaba

    2011-03-22

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  5. Introduction to fluorescence

    CERN Document Server

    Jameson, David M

    2014-01-01

    "An essential contribution to educating scientists in the principles of fluorescence. It will also be an important addition to the libraries of practitioners applying the principles of molecular fluorescence."-Ken Jacobson, Kenan Distinguished Professor of Cell Biology and Physiology, University of North Carolina at Chapel Hill"An exquisite compendium of fluorescence and its applications in biochemistry enriched by a very exciting historical perspective. This book will become a standard text for graduate students and other scientists."-Drs. Zygmunt (Karol) Gryczynski and Ignacy Gryczynski, University of North Texas Health Science Center"… truly a masterwork, combining clarity, precision, and good humor. The reader, novice or expert, will be pleased with the text and will not stop reading. It is a formidable account of the fluorescence field, which has impacted the life sciences so considerably in the last 60 years."-Jerson L. Silva, M.D., Ph.D., Professor and Director, National Institute of Science and Tech...

  6. Functional Fluorescent Organic Nanoparticles

    OpenAIRE

    Campioli, Elisa

    2013-01-01

    This thesis presents an extensive study on fluorescent organic nanoparticles and fluorescent organic binary and ternary nanoassemblies. In particular the attention is focused on the preparation and characterization of organic nanoparticles and new nanocomposites obtained from different types of small organic molecules, their stabilization and the use of these materials for biological and optoelectronics applications. The work deals at the beginning with the description of some methods used...

  7. Effects of plant sterols derived from Aloe vera gel on human dermal fibroblasts in vitro and on skin condition in Japanese women

    Directory of Open Access Journals (Sweden)

    Tanaka M

    2015-02-01

    Full Text Available Miyuki Tanaka,1 Eriko Misawa,1 Koji Yamauchi,1 Fumiaki Abe,1 Chiaki Ishizaki2 1Functional Food Research Department, Food Science and Technology Institute, Morinaga Milk Industry Co, Ltd, Zama, Kanagawa, 2Ebisu Skin Research Center, Inforward, Inc., Tokyo, Japan Background: Aloe is known for its topical use for treating wounds and burns. Many previous studies reported the healing effects of Aloe vera. However, there are few clinical studies on the effect of orally administered A. vera gel on the skin. Aloe sterols are a type of plant sterols that have the capability to regulate the metabolism of glucose and lipids. In a recent study, we confirmed that ingested Aloe sterols reached the peripheral tissues through the bloodstream. However, their influence on dermal fibroblasts has not been investigated. Methods: First, we investigated the capability of Aloe sterols (cycloartenol and lophenol to stimulate human dermal fibroblasts in vitro. Then, we investigated the effect of intake of Aloe vera gel powder (AVGP containing 40 µg Aloe sterols on the skin conditions in Japanese women with dry skin in a randomized, double-blind, placebo-controlled trial. Results: After cocultivation with Aloe sterols, the production of collagen and hyaluronic acid increased by approximately two-fold and 1.5-fold, and gene expression levels of these enzymes responsible for their synthesis were also observed in human dermal fibroblasts. An increase in arm skin hydration was observed at 8 weeks in the AVGP group, whereas a slight decrease in arm skin hydration was noted in the placebo group. However, there was no statistical difference between AVGP and placebo groups in skin moisture. In subgroup analysis, the change in the mean wrinkle depth was significantly lower in the AVGP group than in the control group. In addition, percent body fat after 8 weeks was significantly lower in the AVGP group. No AVGP intake-dependent harmful phenomenon was observed during the intake

  8. Comparison of bile salt/phosphatidylcholine mixed micelles in solubilization to sterols and stability.

    Science.gov (United States)

    Guo, Qin; Cai, Jie; Li, Pengyu; Xu, Dongling; Ni, Xiaomin; Wen, Hui; Liu, Dan; Lin, Suizhen; Hu, Haiyan

    2016-01-01

    Androst-3β,5α,6β-triol (Triol) is a promising neuroprotective agent, but its poor solubility restricts its development into parenteral preparations. In this study, Triol is significantly solubilized by bile salt/phosphatidylcholine mixed micelles (BS/PC-MM). All BS/PC-MM systems are tested to remarkably improve the drug solubility with various stabilities after drug loading. Among them, the sodium glycocholate (SGC)/egg phosphatidylcholine (EPC) system with 2:1 ratio in weight and the total concentration of SGC and EPC of 100 mg/mL is proved to produce stable mixed micelles with high drug loading. It is found that the stability of drug-loaded mixed micelles is quite different, which might be related to the change in critical micelle concentration (CMC) after incorporating drugs. SGC/EPC and SGC/soya phosphatidylcholine (SPC) remain transparent under accelerated conditions and manifest a decreased CMC (dropping from 0.105 to 0.056 mg/mL and from 0.067 to 0.024 mg/mL, respectively). In contrast, swine bile acid-sodium salt (SBA-Na)/PC and sodium deoxycholate (SDC)/PC are accompanied by drug precipitation and reached the maximum CMC on the first and the third days, respectively. Interestingly, the variation of CMC under accelerated testing conditions highly matches the drug-precipitating event in the primary stability experiment. In brief, the bile salt/phosphatidylcholine system exists as a potential strategy of improving sterol drug solubility. CMC variation under accelerated testing conditions might be a simple and easy method to predict the stability of drug-loaded mixed micelles.

  9. Overexpression of Sterol Carrier Protein 2 in Patients with Hereditary Cholesterol Gallstones

    Directory of Open Access Journals (Sweden)

    Zhang Ju

    2011-02-01

    Full Text Available Abstract Background Lithogenic bile is the major cause of cholesterol gallstone, but its pathogenesis is not well understood. The hypersecretion of biliary cholesterol is believed to be an important cause of lithogenic bile. Sterol Carrier Protein 2 (SCP2 participates in cholesterol trafficking and lipid metabolism in hepatocytes and may play a key role in cholesterol gallstone formation. Methods 21 cholesterol gallstone genealogies were studied to investigate the expression of SCP2 gene in liver tissue of hereditary and non-hereditary cholesterol gallstone patients as well as non-gallstone patients. The mRNA expression of liver SCP2 in 28 hereditary patients, 30 non-hereditary cholesterol gallstone patients and 32 non-gallstone patients was measured by Reverse Transcription Polymerase Chain Reaction (RT-PCR. The protein expression of liver SCP2 was also detected in all the patients by Western blotting. At the same time, the bile was also analyzed with biochemical techniques and the Cholesterol Saturation Index (CSI was calculated. Results The mRNA and protein expression of SCP2 was significantly increased in cholesterol gallstone patients compared to those of non-gallstone patients. Moreover, SCP2 was expressed at higher levels in hereditary cholesterol gallstone patients than that of non-hereditary cholesterol gallstone patients. There was significant difference observed in CSI between cholesterol gallstone patients and non-gallstone patients, but not in CSI between hereditary and non-hereditary cholesterol gallstone patients. Conclusions SCP2 was overexpressed in hereditary cholesterol gallstone patients compared to non-hereditary cholesterol gallstone patients. This finding indicated that SCP2 might be one of the genetic factors contributing to cholesterol gallstone formation, which was always accompanied by the increase of bile lithogenicity.

  10. Human Sterol Regulatory Element-Binding Protein 1a Contributes Significantly to Hepatic Lipogenic Gene Expression

    Directory of Open Access Journals (Sweden)

    Andreas Bitter

    2015-01-01

    Full Text Available Background/Aims: Sterol regulatory element-binding protein (SREBP 1, the master regulator of lipogenesis, was shown to be associated with non-alcoholic fatty liver disease, which is attributed to its major isoform SREBP1c. Based on studies in mice, the minor isoform SREBP1a is regarded as negligible for hepatic lipogenesis. This study aims to elucidate the expression and functional role of SREBP1a in human liver. Methods: mRNA expression of both isoforms was quantified in cohorts of human livers and primary human hepatocytes. Hepatocytes were treated with PF-429242 to inhibit the proteolytic activation of SREBP precursor protein. SREBP1a-specifc and pan-SREBP1 knock-down were performed by transfection of respective siRNAs. Lipogenic SREBP-target gene expression was analyzed by real-time RT-PCR. Results: In human liver, SREBP1a accounts for up to half of the total SREBP1 pool. Treatment with PF-429242 indicated SREBP-dependent auto-regulation of SREBP1a, which however was much weaker than of SREBP1c. SREBP1a-specifc knock-down also reduced significantly the expression of SREBP1c and of SREBP-target genes. Regarding most SREBP-target genes, simultaneous knock-down of both isoforms resulted in effects of only similar extent as SREBP1a-specific knock-down. Conclusion: We here showed that SREBP1a is significantly contributing to the human hepatic SREBP1 pool and has a share in human hepatic lipogenic gene expression.

  11. Cloning and expression of a cDNA encoding human sterol carrier protein 2

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Ritsu; Kallen, C.B.; Babalola, G.O.; Rennert, H.; Strauss, J.F. III (Univ. of Pennsylvania School of Medicine, Philadelphia (United States)); Billheimer, J.T. (E.I. DuPont de Nemours, Inc., Wilmington, DE (United States))

    1991-01-15

    The authors report the cloning and expression of a cDNA encoding human sterol carrier protein 2 (SCP{sub 2}). The 1.3-kilobase (kb) cDNA contains an open reading frame which encompasses a 143-amino acid sequence which is 89% identical to the rat SCP{sub 2} amino acid sequence. The deduced amino acid sequence of the polypeptide reveals a 20-residue amino-terminal leader sequence in front of the mature polypeptide, which contains a carboxyl-terminal tripeptide (Ala-Lys-Leu) related to the peroxisome targeting sequence. The expressed cDNA in COS-7 cells yields a 15.3-kDa polypeptide and increased amounts of a 13.2-kDa polypeptide, both reacting with a specific rabbit antiserum to rat liver SCP{sub 2}. The cDNA insert hybridizes with 3.2- and 1.8-kb mRNA species in human liver poly(A){sup +} RNA. In human fibroblasts and placenta the 1.8-kb mRNA was most abundant. Southern blot analysis suggests either that there are multiple copies of the SCP{sub 2} gene in the human genome or that the SCP{sub 2} gene is very large. Coexpression of the SCP{sub 2} cDNA with expression vectors for cholesterol side-chain cleavage enzyme and adrenodoxin resulted in a 2.5-fold enhancement of progestin synthesis over that obtained with expression of the steroidogenic enzyme system alone. These findings are concordant with the notion that SCP{sub 2} plays a role in regulating steroidogenesis, among other possible functions.

  12. Oral Delivery of a Synthetic Sterol Reduces Axonopathy and Inflammation in a Rodent Model of Glaucoma

    Science.gov (United States)

    Lambert, Wendi S.; Carlson, Brian J.; Formichella, Cathryn R.; Sappington, Rebecca M.; Ahlem, Clarence; Calkins, David J.

    2017-01-01

    Glaucoma is a group of optic neuropathies associated with aging and sensitivity to intraocular pressure (IOP). The disease is the leading cause of irreversible blindness worldwide. Early progression in glaucoma involves dysfunction of retinal ganglion cell (RGC) axons, which comprise the optic nerve. Deficits in anterograde transport along RGC axons to central visual structures precede outright degeneration, and preventing these deficits is efficacious at abating subsequent progression. HE3286 is a synthetic sterol derivative that has shown therapeutic promise in models of inflammatory disease and neurodegenerative disease. We examined the efficacy of HE3286 oral delivery in preventing loss of anterograde transport in an inducible model of glaucoma (microbead occlusion). Adult rats received HE3286 (20 or 100 mg/kg) or vehicle daily via oral gavage for 4 weeks. Microbead occlusion elevated IOP ~30% in all treatment groups, and elevation was not affected by HE3286 treatment. In the vehicle group, elevated IOP reduced anterograde axonal transport to the superior colliculus, the most distal site in the optic projection, by 43% (p = 0.003); HE3286 (100 mg/kg) prevented this reduction (p = 0.025). HE3286 increased brain-derived neurotrophic factor (BDNF) in the optic nerve head and retina, while decreasing inflammatory and pathogenic proteins associated with elevated IOP compared to vehicle treatment. Treatment with HE3286 also increased nuclear localization of the transcription factor NFκB in collicular and retinal neurons, but decreased NFκB in glial nuclei in the optic nerve head. Thus, HE3286 may have a neuroprotective influence in glaucoma, as well as other chronic neurodegenerations. PMID:28223915

  13. Effects of Dietary Plant Sterols and Stanol Esters with Low- and High-Fat Diets in Chronic and Acute Models for Experimental Colitis.

    Science.gov (United States)

    te Velde, Anje A; Brüll, Florence; Heinsbroek, Sigrid E M; Meijer, Sybren L; Lütjohann, Dieter; Vreugdenhil, Anita; Plat, Jogchum

    2015-10-15

    In this study, we evaluated the effects of dietary plant sterols and stanols as their fatty acid esters on the development of experimental colitis. The effects were studied both in high- and low-fat diet conditions in two models, one acute and another chronic model of experimental colitis that resembles gene expression in human inflammatory bowel disease (IBD). In the first experiments in the high fat diet (HFD), we did not observe a beneficial effect of the addition of plant sterols and stanols on the development of acute dextran sulphate sodium (DSS) colitis. In the chronic CD4CD45RB T cell transfer colitis model, we mainly observed an effect of the presence of high fat on the development of colitis. In this HFD condition, the presence of plant sterol or stanol did not result in any additional effect. In the second experiments with low fat, we could clearly observe a beneficial effect of the addition of plant sterols on colitis parameters in the T cell transfer model, but not in the DSS model. This positive effect was related to the gender of the mice and on Treg presence in the colon. This suggests that especially dietary plant sterol esters may improve intestinal inflammation in a T cell dependent manner.

  14. 三种植物甾醇调控SRE元件和3T3-L1细胞脂肪化活性的作用%Effects of Three Plant Sterols on Activity of Sterol Regulatory Element and Adipogenesis of 3T3L-1

    Institute of Scientific and Technical Information of China (English)

    陈彦光; 张弦; 刘健

    2013-01-01

    [目的]为了研究植物甾醇对脂质代谢的调控作用.[方法]利用所构建的SRE荧光素酶活性测定系统,体外考察了豆甾醇、β-谷甾醇和菜油甾醇3种常见的植物甾醇对SRE元件的调控活性.[结果]植物甾醇能够增强SRE元件活性.植物甾醇也可以增加3T3-L1细胞的脂肪化作用.[结论]植物甾醇可能正调控脂质的合成.%[Objective] The research aimed to study the regulating effect of plant sterol on lipid metabolism.[Method] Luciferase reporter vector pGL3-basic that contained one or three sterol regulatory element (SRE) was transfected into HepG2,and luciferase activity of three plant sterols (stigmasterol,β-sitosterol and campesterol) was analyzed.[Result] The plant sterols had positive regulator of SRE.And plant sterols could increase adipogenesis of 3T3L-1.[Conclusion] Plant sterols could increase adipogenesis by increasing SRE activity.

  15. Composition and sources of aliphatic lipids and sterols in sediments of a tropical island, southern South China Sea: preliminary assessment.

    Science.gov (United States)

    Mohd Tahir, N; Pang, S Y; Abdullah, N A; Suratman, S

    2013-12-01

    Near-shore surface sediment was collected from five stations off Redang Island located on the eastern coast of Peninsular Malaysia. Freeze-dried sediments were Soxhlet extracted and then fractionated using column chromatography into aliphatic and polar fractions. Determination of these fractions was carried out using gas chromatography mass spectrometry. The concentration of total resolved aliphatic hydrocarbons in sediments ranged from 157 to 308 ng/g. The distribution of aliphatic fraction showed the presence of n-alkanes ranging from nC15 to nC33 with a minor odd-to-even predominance exhibiting carbon maximum, depending on station, at nC17, nC26, nC29 or nC31. Calculation of Carbon Preference Index (CPI) for CPI(15-33) gave values ranging from 1.09 to 1.46. n-Alkanol in all sediment exhibits even-to-odd carbon predominance ranging from nC16 to nC28 and maximising at nC22. n-Fatty acids distribution ranged from nC14 to nC24 with a dominant maximum at nC16 and exhibiting high values of short chain fatty acids (≤nC20) to long chain fatty acids (>nC20) ratios. Unsaturated fatty acids, particularly nC16:1 and nC18:1 is also ubiquitous in all samples. Cholesterol is the most abundant compound amongst the sterol group ranging from 42.8 to 62.6% of the total sterols. β-Sitosterol, brassicasterol and stigmasterol, are also present but of relatively lower amount. These observations suggest that the aliphatic lipids and sterols in the study area originate, mainly, from biogenic sources of marine microbial with minor contribution from epiticular waxes of terrestrial plants.

  16. The occurrence of PAHs and faecal sterols in Dublin Bay and their influence on sedimentary microbial communities.

    Science.gov (United States)

    Murphy, Brian T; O'Reilly, Shane S; Monteys, Xavier; Reid, Barry F; Szpak, Michal T; McCaul, Margaret V; Jordan, Sean F; Allen, Christopher C R; Kelleher, Brian P

    2016-05-15

    The source, concentration, and potential impact of sewage discharge and incomplete organic matter (OM) combustion on sedimentary microbial populations were assessed in Dublin Bay, Ireland. Polycyclic aromatic hydrocarbons (PAHs) and faecal steroids were investigated in 30 surface sediment stations in the bay. Phospholipid fatty acid (PLFA) content at each station was used to identify and quantify the broad microbial groups present and the impact of particle size, total organic carbon (%TOC), total hydrogen (%H) and total nitrogen (%N) was also considered. Faecal sterols were found to be highest in areas with historical point sources of sewage discharge. PAH distribution was more strongly associated with areas of deposition containing high %silt and %clay content, suggesting that PAHs are from diffuse sources such as rainwater run-off and atmospheric deposition. The PAHs ranged from 12 to 3072ng/g, with 10 stations exceeding the suggested effect range low (ERL) for PAHs in marine sediments. PAH isomer pair ratios and sterol ratios were used to determine the source and extent of pollution. PLFAs were not impacted by sediment type or water depth but were strongly correlated to, and influenced by PAH and sewage levels. Certain biomarkers such as 10Me16:0, i17:0 and a17:0 were closely associated with PAH polluted sediments, while 16:1ω9, 16:1ω7c, Cy17:0, 18:1ω6, i16:0 and 15:0 all have strong positive correlations with faecal sterols. Overall, the results show that sedimentary microbial communities are impacted by anthropogenic pollution. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Crystal Structures of Trypanosoma brucei Sterol 14[alpha]-Demethylase and Implications for Selective Treatment of Human Infections

    Energy Technology Data Exchange (ETDEWEB)

    Lepesheva, Galina I.; Park, Hee-Won; Hargrove, Tatiana Y.; Vanhollebeke, Benoit; Wawrzak, Zdzislaw; Harp, Joel M.; Sundaramoorthy, Munirathinam; Nes, W. David; Pays, Etienne; Chaudhuri, Minu; Villalta, Fernando; Waterman, Michael R. (ULdB); (Vanderbilt); (TTU); (Toronto); (NWU); (Meharry)

    2010-01-25

    Sterol 14{alpha}-demethylase (14DM, the CYP51 family of cytochrome P450) is an essential enzyme in sterol biosynthesis in eukaryotes. It serves as a major drug target for fungal diseases and can potentially become a target for treatment of human infections with protozoa. Here we present 1.9 {angstrom} resolution crystal structures of 14DM from the protozoan pathogen Trypanosoma brucei, ligand-free and complexed with a strong chemically selected inhibitor N-1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethyl-4-(5-phenyl-1,3,4-oxadi-azol-2-yl)benzamide that we previously found to produce potent antiparasitic effects in Trypanosomatidae. This is the first structure of a eukaryotic microsomal 14DM that acts on sterol biosynthesis, and it differs profoundly from that of the water-soluble CYP51 family member from Mycobacterium tuberculosis, both in organization of the active site cavity and in the substrate access channel location. Inhibitor binding does not cause large scale conformational rearrangements, yet induces unanticipated local alterations in the active site, including formation of a hydrogen bond network that connects, via the inhibitor amide group fragment, two remote functionally essential protein segments and alters the heme environment. The inhibitor binding mode provides a possible explanation for both its functionally irreversible effect on the enzyme activity and its selectivity toward the 14DM from human pathogens versus the human 14DM ortholog. The structures shed new light on 14DM functional conservation and open an excellent opportunity for directed design of novel antiparasitic drugs.

  18. Determination of Dynamics of Plant Plasma Membrane Proteins with Fluorescence Recovery and Raster Image Correlation Spectroscopy.

    Science.gov (United States)

    Laňková, Martina; Humpolíčková, Jana; Vosolsobě, Stanislav; Cit, Zdeněk; Lacek, Jozef; Čovan, Martin; Čovanová, Milada; Hof, Martin; Petrášek, Jan

    2016-04-01

    A number of fluorescence microscopy techniques are described to study dynamics of fluorescently labeled proteins, lipids, nucleic acids, and whole organelles. However, for studies of plant plasma membrane (PM) proteins, the number of these techniques is still limited because of the high complexity of processes that determine the dynamics of PM proteins and the existence of cell wall. Here, we report on the usage of raster image correlation spectroscopy (RICS) for studies of integral PM proteins in suspension-cultured tobacco cells and show its potential in comparison with the more widely used fluorescence recovery after photobleaching method. For RICS, a set of microscopy images is obtained by single-photon confocal laser scanning microscopy (CLSM). Fluorescence fluctuations are subsequently correlated between individual pixels and the information on protein mobility are extracted using a model that considers processes generating the fluctuations such as diffusion and chemical binding reactions. As we show here using an example of two integral PM transporters of the plant hormone auxin, RICS uncovered their distinct short-distance lateral mobility within the PM that is dependent on cytoskeleton and sterol composition of the PM. RICS, which is routinely accessible on modern CLSM instruments, thus represents a valuable approach for studies of dynamics of PM proteins in plants.

  19. An unexpectedly high degree of specialization and a widespread involvement in sterol metabolism among the C. elegans putative aminophospholipid translocases

    Directory of Open Access Journals (Sweden)

    Miteva Yana

    2008-10-01

    Full Text Available Abstract Background P-type ATPases in subfamily IV are exclusively eukaryotic transmembrane proteins that have been proposed to directly translocate the aminophospholipids phosphatidylserine and phosphatidylethanolamine from the exofacial to the cytofacial monolayer of the plasma membrane. Eukaryotic genomes contain many genes encoding members of this subfamily. At present it is unclear why there are so many genes of this kind per organism or what individual roles these genes perform in organism development. Results We have systematically investigated expression and developmental function of the six, tat-1 through 6, subfamily IV P-type ATPase genes encoded in the Caenorhabditis elegans genome. tat-5 is the only ubiquitously-expressed essential gene in the group. tat-6 is a poorly-transcribed recent duplicate of tat-5. tat-2 through 4 exhibit tissue-specific developmentally-regulated expression patterns. Strong expression of both tat-2 and tat-4 occurs in the intestine and certain other cells of the alimentary system. The two are also expressed in the uterus, during spermatogenesis and in the fully-formed spermatheca. tat-2 alone is expressed in the pharyngeal gland cells, the excretory system and a few cells of the developing vulva. The expression pattern of tat-3 is almost completely different from those of tat-2 and tat-4. tat-3 expression is detectable in the steroidogenic tissues: the hypodermis and the XXX cells, as well as in most cells of the pharynx (except gland, various tissues of the reproductive system (except uterus and spermatheca and seam cells. Deletion of tat-1 through 4 individually interferes little or not at all with the regular progression of organism growth and development under normal conditions. However, tat-2 through 4 become essential for reproductive growth during sterol starvation. Conclusion tat-5 likely encodes a housekeeping protein that performs the proposed aminophospholipid translocase function routinely

  20. Sterol Regulatory Element Binding Protein 1a Regulates Hepatic Fatty Acid Partitioning by Activating Acetyl Coenzyme A Carboxylase 2

    OpenAIRE

    Im, Seung-Soon; Hammond, Linda E.; Yousef, Leyla; Nugas-Selby, Cherryl; Shin, Dong-Ju; Seo, Young-Kyo; Fong, Loren G.; Young, Stephen G.; Osborne, Timothy F.

    2009-01-01

    We generated a line of mice in which sterol regulatory element binding protein 1a (SREBP-1a) was specifically inactivated by insertional mutagenesis. Homozygous mutant mice were completely viable despite expressing SREBP-1a mRNA below 5% of normal, and there were minimal effects on expression of either SREBP-1c or -2. Microarray expression studies in liver, where SREBP-1a mRNA is 1/10 the level of the highly similar SREBP-1c, demonstrated that only a few genes were affected. The only downregu...

  1. Isolation and structure elucidation of halymeniaol, a new antimalarial sterol derivative from the red alga Halymenia floresii.

    Science.gov (United States)

    Meesala, Srinu; Gurung, Pratima; Karmodiya, Krishanpal; Subrayan, Parameswaran; Watve, Milind G

    2017-06-29

    A new mono-hydroxy acetylated sterol derivative: 12β-hydroxy-3β, 15α, 16β-triacetoxy-cholest-5-en-7-one (halymeniaol) (1), and cholesterol (2) were isolated from the marine red alga Halymenia floresii. The structure of the compound 1 (halymeniaol) was established from its spectral data, derived from HRMS/MS and 2D NMR. Compound 1 exhibited growth inhibitory activity against chloroquine-resistant Plasmodium falciparum 3D7 strain with an IC50 of 3.0 μM.

  2. Genes encoding chimeras of Neurospora crassa erg-3 and human TM7SF2 proteins fail to complement Neurospora and yeast sterol C-14 reductase mutants

    Indian Academy of Sciences (India)

    A Prakash; Durgadas P Kasbekar

    2002-03-01

    The human gene TM7SF2 encodes a polypeptide (SR-1) with high sequence similarity to sterol C-14 reductase, a key sterol biosynthetic enzyme in fungi, plants and mammals. In Neurospora and yeast this enzyme is encoded by the erg-3 and erg24 genes respectively. In an effort to demonstrate sterol C-14 reductase activity for SR-1 we constructed six recombinant genes coding for chimeras of the Neurospora erg-3 and SR-1 protein sequences and tested them for complementation of the Neurospora erg-3 mutant. To our surprise, all the chimeras failed to complement erg-3. A few of the chimeric proteins were also tested against the yeast erg24 mutant, but again there was no complementation. We discuss some reasons that might account for these unexpected findings.

  3. Antibacterial, antioxidant and cytotoxic studies of total saponin, alkaloid and sterols contents of decoction of Joshanda: identification of components through thin layer chromatography.

    Science.gov (United States)

    Khan, Haroon; Khan, Murad Ali; Abdullah

    2015-03-01

    The current study was aimed to assess antibacterial, antioxidant and cytotoxic activity of total saponin, alkaloid and sterol contents of Joshanda decoction followed by its constituent's analysis via thin layer chromatography (TLC). Saponins and alkaloids showed prominent antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Bacillus cereus and Klebsiella pneumoniae whereas sterols only against S. aureus. Saponin and alkaloid contents of 97 and 108 µg/ml, respectively, showed prominent free radical scavenging activity against 1,1-diphenyl-2-picrylhidrazyl, with mild cytotoxicity in brine shrimp cytotoxic test. Under ultraviolet light at 254 nm, TLC of total saponins showed eight different compounds, total sterols comprising three while total alkaloids two compounds of various polarities. It is concluded that the various contents of Joshanda decoction possess outstanding susceptibility against bacteria implicating primarily upper respiratory tract infections augmented by strong antioxidant activity. © The Author(s) 2012.

  4. 烟草甾醇合成代谢分子调控研究进展%Advances in the Molecular Regulation of Tobacco Sterol Biosynthesis Metabolism

    Institute of Scientific and Technical Information of China (English)

    闫宁; 龚达平; 张忠锋

    2015-01-01

    Plant sterols in tobacco leaves can generate the carcinogen - polycyclic aromatic hydrocarbons (PAHs) in the combustion process of cigarette. In this article, the roles of plant sterols in tobacco harm reduction research, the regulation of plant growth and development, and the response to plant stress were primarily discussed, and the plant sterol biosynthetic pathway and key enzymes in this pathway were mainly introduced.%烟叶中的甾醇在卷烟燃烧过程中生成致癌物-多环芳烃(PAHs)。笔者主要阐述了植物甾醇在卷烟减害研究、调控植物生长发育和响应植物胁迫中的作用,重点介绍了植物甾醇合成代谢途径以及该途径中的关键酶基因。

  5. Alterations in composition of sterols and in properties of erythrocyte membranes in rats with Shvetz experimental leukosis and after UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Palamarchyuk, V.I.; Trikash, I.O. (AN Ukrainskoj SSR, Kiev. Inst. Biokhimii)

    1983-05-01

    Sterol composition of erythrocyte membrane is studied in experimental Schwetz leukosis. Interconnections of alteration in sterol composition and membrane properties are investigated, as well as the effect of UV-radiation on the alteration of sterol composition of erythrocyte membrane and lifetime of animals With leukosis. The effect of UV-radiation on survival of the leukosis animals has been studied which showed that irradiation of rats in the dose of 8 mWt/min/cm/sup 2/ for 12 days increases the lifetime of animals by several days, i.e. increases resistance of animals to leukosis. In the case of short-time UV-radiation of rats the cholesterine amount in erythrocyte membranes increases by 9% as compared with the norm, simultaneously, other substances appear. Acidic resistance of erythrocytes of irradiated animals also increases. The supposition is made that alterations promote the increase of organism resistance to leukosis.

  6. Low concentrations of the non-ionic detergent Nonidet P-40 interfere with sterol biogenesis and viability of the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Hronská, Lucia; Mrózová, Zuzana; Valachovic, Martin; Hapala, Ivan

    2004-09-01

    Mild non-ionic detergents are used for solubilization of hydrophobic substrates in yeast growth media at concentrations 0.1-1%. Our data show that low concentrations of Nonidet P-40 may significantly affect lipid biogenesis in the yeast Saccharomyces cerevisiae. The uptake and esterification of external [4-14C]-cholesterol is strongly reduced in hem1 mutants treated with low concentrations of Nonidet P-40. Significant inhibitory effect of NP-40 on sterol uptake and esterification was evident both in non-growing and growing cells supplemented with external cholesterol. Increased levels of sterol precursors (squalene, lanosterol) in hem1 cells grown in complex medium with cholesterol indicated general interference of NP-40 with sterol biosynthesis. NP-40 in the growth medium affected also cell viability estimated as the colony forming ability. More attention should be therefore paid to possible effects of mild detergents at low concentrations generally considered to be harmless, especially in cells with disturbed lipid biogenesis.

  7. Validation of a method for the determination of sterols and triterpenes in the aerial part of Justicia anselliana (Nees) T. Anders by capillary gas chromatography.

    Science.gov (United States)

    Kpoviéssi, Dossou Sika Salomé; Gbaguidi, Fernand; Gbénou, Joachim; Accrombessi, Georges; Moudachirou, Mansourou; Rozet, Eric; Hubert, Philippe; Quetin-Leclercq, Joëlle

    2008-12-01

    An accurate and sensitive method, combining soxhlet extraction, solid phase-extraction and capillary gas chromatography is described for the quantitative determination of one triterpene (lupeol) and three sterols (stigmasterol, campesterol and beta-sitosterol) and the detection of another triterpene (alpha-amyrin) from the aerial part of Justicia anselliana. This is the first method allowing the quantification of sterols and triterpenes in this plant. It has been fully validated in order to be able to compare the sterol and triterpene composition of different samples of J. anselliana and therefore help to explain the allelopathic activity due to these compounds. This method showed that the aerial part of J. anselliana contained (292+/-2)mg/kg of lupeol, (206+/-1)mg/kg of stigmasterol, (266+/-2)mg/kg of campesterol and (184+/-9)mg/kg of beta-sitosterol.

  8. Nine New Fluorescent Probes

    Science.gov (United States)

    Lin, Tsung-I.; Jovanovic, Misa V.; Dowben, Robert M.

    1989-06-01

    Absorption and fluorescence spectroscopic studies are reported here for nine new fluorescent probes recently synthesized in our laboratories: four pyrene derivatives with substituents of (i) 1,3-diacetoxy-6,8-dichlorosulfonyl, (ii) 1,3-dihydroxy-6,8-disodiumsulfonate, (iii) 1,3-disodiumsulfonate, and (iv) l-ethoxy-3,6,8-trisodiumsulfonate groups, and five [7-julolidino] coumarin derivatives with substituents of (v) 3-carboxylate-4-methyl, (vi) 3- methylcarboxylate, (vii) 3-acetate-4-methyl, (viii) 3-propionate-4-methyl, and (ix) 3-sulfonate-4-methyl groups. Pyrene compounds i and ii and coumarin compounds v and vi exhibit interesting absorbance and fluorescence properties: their absorption maxima are red shifted compared to the parent compound to the blue-green region, and the band width broadens considerably. All four blue-absorbing dyes fluoresce intensely in the green region, and the two pyrene compounds emit at such long wavelengths without formation of excimers. The fluorescence properties of these compounds are quite environment-sensitive: considerable spectral shifts and fluorescence intensity changes have been observed in the pH range from 3 to 10 and in a wide variety of polar and hydrophobic solvents with vastly different dielectric constants. The high extinction and fluorescence quantum yield of these probes make them ideal fluorescent labeling reagents for proteins, antibodies, nucleic acids, and cellular organelles. The pH and hydrophobicity-dependent fluorescence changes can be utilized as optical pH and/or hydrophobicity indicators for mapping environmental difference in various cellular components in a single cell. Since all nine probes absorb in the UV, but emit at different wavelengths in the visible, these two groups of compounds offer an advantage of utilizing a single monochromatic light source (e.g., a nitrogen laser) to achieve multi-wavelength detection for flow cytometry application. As a first step to explore potential application in

  9. Stroboscopic fluorescence lifetime imaging.

    Science.gov (United States)

    Holton, Mark D; Silvestre, Oscar R; Errington, Rachel J; Smith, Paul J; Matthews, Daniel R; Rees, Paul; Summers, Huw D

    2009-03-30

    We report a fluorescence lifetime imaging technique that uses the time integrated response to a periodic optical excitation, eliminating the need for time resolution in detection. A Dirac pulse train of variable period is used to probe the frequency response of the total fluorescence per pulse leading to a frequency roll-off that is dependent on the relaxation rate of the fluorophores. The technique is validated by demonstrating wide-field, realtime, lifetime imaging of the endocytosis of inorganic quantum dots by a cancer cell line. Surface charging of the dots in the intra-cellular environment produces a switch in the fluorescence lifetime from approximately 40 ns to technique offers lifetime based imaging at video rates with standard CCD cameras and has application in probing millisecond cell dynamics and in high throughput imaging assays.

  10. Sterol content analysis suggests altered eburicol 14alpha-demethylase (CYP51) activity in isolates of Mycosphaerella graminicola adapted to azole fungicides.

    Science.gov (United States)

    Bean, Tim P; Cools, Hans J; Lucas, John A; Hawkins, Nathaniel D; Ward, Jane L; Shaw, Michael W; Fraaije, Bart A

    2009-06-01

    The recent decline in the effectiveness of some azole fungicides in controlling the wheat pathogen Mycosphaerella graminicola has been associated with mutations in the CYP51 gene encoding the azole target, the eburicol 14alpha-demethylase (CYP51), an essential enzyme of the ergosterol biosynthesis pathway. In this study, analysis of the sterol content of M. graminicola isolates carrying different variants of the CYP51 gene has revealed quantitative differences in sterol intermediates, particularly the CYP51 substrate eburicol. Together with CYP51 gene expression studies, these data suggest that mutations in the CYP51 gene impact on the activity of the CYP51 protein.

  11. Aloe sterol supplementation improves skin elasticity in Japanese men with sunlight-exposed skin: a 12-week double-blind, randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Tanaka M

    2016-11-01

    Full Text Available Miyuki Tanaka,1 Yuki Yamamoto,2 Eriko Misawa,1 Kazumi Nabeshima,1 Marie Saito,1 Koji Yamauchi,1 Fumiaki Abe,1 Fukumi Furukawa2 1Functional Food Ingredients Department, Food Ingredients & Technology Institute, Morinaga Milk Industry Co., Ltd., Zama, Kanagawa, 2Department of Dermatology, Wakayama Medical University, Kimiidera, Wakayama, Japan Background/objective: Recently, it was confirmed that the daily oral intake of plant sterols of Aloe vera gel (Aloe sterol significantly increases the skin barrier function, moisture, and elasticity in photoprotected skin. This study aimed to investigate whether Aloe sterol intake affected skin conditions following sunlight exposure in Japanese men. Methods: We performed a 12-week, randomized, double-blind, placebo-controlled study to evaluate the effects of oral Aloe sterol supplementation on skin conditions in 48 apparently healthy men (age range: 30–59 years; average: 45 years. The subjects were instructed to expose the measurement position of the arms to the sunlight outdoors every day for 12 weeks. The skin parameters were measured at 0 (baseline, 4, 8, and 12 weeks. Results: Depending on the time for the revelation of the sunlight, the b* value and melanin index increased and the skin moisture decreased. After taking an Aloe sterol tablet daily for 12 weeks, the skin elasticity index (R2, R5, and R7 levels were significantly higher than the baseline value. There were no differences between the groups in these skin elasticity values. In the subgroup analysis of subjects aged <46 years, the change in the R5 and R7 was significantly higher in the Aloe group than in the placebo group at 8 weeks (P=0.0412 and P=0.0410, respectively. There was a difference in the quantity of sun exposure between each subject, and an additional clinical study that standardizes the amount of ultraviolet rays is warranted. No Aloe sterol intake-dependent harmful phenomenon was observed during the intake period

  12. Evidence for a role of sterol 27-hydroxylase in glucocorticoid metabolism in vivo.

    Science.gov (United States)

    Vögeli, Isabelle; Jung, Hans H; Dick, Bernhard; Erickson, Sandra K; Escher, Robert; Funder, John W; Frey, Felix J; Escher, Geneviève

    2013-11-01

    The intracellular availability of glucocorticoids is regulated by the enzymes 11β-hydroxysteroid dehydrogenase 1 (HSD11B1) and 11β-hydroxysteroid dehydrogenase 2 (HSD11B2). The activity of HSD11B1 is measured in the urine based on the (tetrahydrocortisol+5α-tetrahydrocortisol)/tetrahydrocortisone ((THF+5α-THF)/THE) ratio in humans and the (tetrahydrocorticosterone+5α-tetrahydrocorticosterone)/tetrahydrodehydrocorticosterone ((THB+5α-THB)/THA) ratio in mice. The cortisol/cortisone (F/E) ratio in humans and the corticosterone/11-dehydrocorticosterone (B/A) ratio in mice are markers of the activity of HSD11B2. In vitro agonist treatment of liver X receptor (LXR) down-regulates the activity of HSD11B1. Sterol 27-hydroxylase (CYP27A1) catalyses the first step in the alternative pathway of bile acid synthesis by hydroxylating cholesterol to 27-hydroxycholesterol (27-OHC). Since 27-OHC is a natural ligand for LXR, we hypothesised that CYP27A1 deficiency may up-regulate the activity of HSD11B1. In a patient with cerebrotendinous xanthomatosis carrying a loss-of-function mutation in CYP27A1, the plasma concentrations of 27-OHC were dramatically reduced (3.8 vs 90-140 ng/ml in healthy controls) and the urinary ratios of (THF+5α-THF)/THE and F/E were increased, demonstrating enhanced HSD11B1 and diminished HSD11B2 activities. Similarly, in Cyp27a1 knockout (KO) mice, the plasma concentrations of 27-OHC were undetectable (<1 vs 25-120 ng/ml in Cyp27a1 WT mice). The urinary ratio of (THB+5α-THB)/THA was fourfold and that of B/A was twofold higher in KO mice than in their WT littermates. The (THB+5α-THB)/THA ratio was also significantly increased in the plasma, liver and kidney of KO mice. In the liver of these mice, the increase in the concentrations of active glucocorticoids was due to increased liver weight as a consequence of Cyp27a1 deficiency. In vitro, 27-OHC acts as an inhibitor of the activity of HSD11B1. Our studies suggest that the expression of CYP27A1

  13. Sterols and polyphenols of fucoids from the Murmansk coast of the Barents Sea

    Directory of Open Access Journals (Sweden)

    Tkach A. V.

    2017-06-01

    Full Text Available The results of polyphenols and sterols content in fucus algae from the Murmansk coast of the Barents Sea have been presented. Maximum concentrations of polyphenols (7.06–9.62 % have been found in all of fucus algae from the Lodeynaya Bay characterized by the highest levels of heavy metal contamination. While comparing Fucoids of Murman by content of polyphenols it has been shown that the minimum values are typical for A. nodosum (1.5–3.3 %, higher concentrations (an average of 1.7–2.0 times higher – for representatives of F. vesiculosus and F. serratus. The character of changes in the content of total polyphenols in fucus algae of Murman has been studied by three-way multivariate analyses of variance (MANOVA. It has been shown that the degree of salinity of sea water is most significant. The factor of the habitat of algae (the complex of individual abiotic characteristics of the specific location has had a smaller influence. Seasonal factor has turned out to be insignificant in relation to the dynamics of accumulation of polyphenols for all investigated Fucoids. However, the detailed study of each species of algae has revealed a seasonal dependence of the polyphenols content for the two species from the Kola Bay, namely representatives of Fucus vesiculosus and Fucus distichus accumulate polyphenols in spring. The most significant influence on the total polyphenols content of algae from Murman has interaction of habitat factors, salinity and season (38.75 %. It has been established that Fucus vesiculosus has the most quantities of fucosterol, total polyphenols and the amount of extractive substances in comparison with other species of the Barents Sea flora, such as F. serratus, F. distichus and A. nodosum. It has been shown that the algae growing in the Yarnyshnaya Bay (Eastern coast of the Barents Sea contain two times more fucosterol and polyphenols than those living in the Belokamennaya Bay, 13 times more than the algae from the cape

  14. Nanosecond fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Leskovar, B.

    1985-03-01

    This article is a summary of a short course lecture given in conjunction with the 1984 Nuclear Science Symposium. Measuring systems for nanosecond fluorescence spectroscopy using single-photon counting techniques are presented. These involve systems based on relaxation-type spark gap light pulser and synchronously pumped mode-locked dye lasers. Furthermore, typical characteristics and optimization of operating conditions of the critical components responsible for the system time resolution are discussed. A short comparison of the most important deconvolution methods for numerical analysis of experimental data is given particularly with respect to the signal-to-noise ratio of the fluorescence signal. 22 refs., 8 figs.

  15. Growth inhibition and ultrastructural alterations induced by Δ24(25-sterol methyltransferase inhibitors in Candida spp. isolates, including non-albicans organisms

    Directory of Open Access Journals (Sweden)

    Nakamura Celso

    2009-04-01

    Full Text Available Abstract Background Although Candida species are commensal microorganisms, they can cause many invasive fungal infections. In addition, antifungal resistance can contribute to failure of treatment. The purpose of this study was to evaluate the antifungal activity of inhibitors of Δ24(25-sterol methyltransferase (24-SMTI, 20-piperidin-2-yl-5α-pregnan-3β-20(R-diol (AZA, and 24(R,S,25-epiminolanosterol (EIL, against clinical isolates of Candida spp., analysing the ultrastructural changes. Results AZA and EIL were found to be potent growth inhibitors of Candida spp. isolates. The median MIC50 was 0.5 μg.ml-1 for AZA and 2 μg.ml-1 for EIL, and the MIC90 was 2 μg.ml-1 for both compounds. All strains used in this study were susceptible to amphotericin B; however, some isolates were fluconazole- and itraconazole-resistant. Most of the azole-resistant isolates were Candida non-albicans (CNA species, but several of them, such as C. guilliermondii, C. zeylanoides, and C. lipolytica, were susceptible to 24-SMTI, indicating a lack of cross-resistance. Reference strain C. krusei (ATCC 6258, FLC-resistant was consistently susceptible to AZA, although not to EIL. The fungicidal activity of 24-SMTI was particularly high against CNA isolates. Treatment with sub-inhibitory concentrations of AZA and EIL induced several ultrastructural alterations, including changes in the cell-wall shape and thickness, a pronounced disconnection between the cell wall and cytoplasm with an electron-lucent zone between them, mitochondrial swelling, and the presence of electron-dense vacuoles. Fluorescence microscopy analyses indicated an accumulation of lipid bodies and alterations in the cell cycle of the yeasts. The selectivity of 24-SMTI for fungal cells versus mammalian cells was assessed by the sulforhodamine B viability assay. Conclusion Taken together, these results suggest that inhibition of 24-SMT may be a novel approach to control Candida spp. infections, including

  16. Expression of SREBP-1c Requires SREBP-2-mediated Generation of a Sterol Ligand for LXR in Livers of Mice

    Science.gov (United States)

    Rong, Shunxing; Cortés, Víctor A; Rashid, Shirya; Anderson, Norma N; McDonald, Jeffrey G; Liang, Guosheng; Moon, Young-Ah; Hammer, Robert E; Horton, Jay D

    2017-01-01

    The synthesis of cholesterol and fatty acids (FA) in the liver is independently regulated by SREBP-2 and SREBP-1c, respectively. Here, we genetically deleted Srebf-2 from hepatocytes and confirmed that SREBP-2 regulates all genes involved in cholesterol biosynthesis, the LDL receptor, and PCSK9; a secreted protein that degrades LDL receptors in the liver. Surprisingly, we found that elimination of Srebf-2 in hepatocytes of mice also markedly reduced SREBP-1c and the expression of all genes involved in FA and triglyceride synthesis that are normally regulated by SREBP-1c. The nuclear receptor LXR is necessary for Srebf-1c transcription. The deletion of Srebf-2 and subsequent lower sterol synthesis in hepatocytes eliminated the production of an endogenous sterol ligand required for LXR activity and SREBP-1c expression. These studies demonstrate that cholesterol and FA synthesis in hepatocytes are coupled and that flux through the cholesterol biosynthetic pathway is required for the maximal SREBP-1c expression and high rates of FA synthesis. DOI: http://dx.doi.org/10.7554/eLife.25015.001 PMID:28244871

  17. Xanthohumol Improves Diet-induced Obesity and Fatty Liver by Suppressing Sterol Regulatory Element-binding Protein (SREBP) Activation.

    Science.gov (United States)

    Miyata, Shingo; Inoue, Jun; Shimizu, Makoto; Sato, Ryuichiro

    2015-08-14

    Sterol regulatory element-binding proteins (SREBPs) are key transcription factors that stimulate the expression of genes involved in fatty acid and cholesterol biosynthesis. Here, we demonstrate that a prenylated flavonoid in hops, xanthohumol (XN), is a novel SREBP inactivator that reduces the de novo synthesis of fatty acid and cholesterol. XN independently suppressed the maturation of SREBPs of insulin-induced genes in a manner different from sterols. Our results suggest that XN impairs the endoplasmic reticulum-to-Golgi translocation of the SREBP cleavage-activating protein (SCAP)-SREBP complex by binding to Sec23/24 and blocking SCAP/SREBP incorporation into common coated protein II vesicles. Furthermore, in diet-induced obese mice, dietary XN suppressed SREBP-1 target gene expression in the liver accompanied by a reduction of the mature form of hepatic SREBP-1, and it inhibited the development of obesity and hepatic steatosis. Altogether, our data suggest that XN attenuates the function of SREBP-1 by repressing its maturation and that it has the potential of becoming a nutraceutical food or pharmacological agent for improving metabolic syndrome.

  18. Xanthohumol Improves Diet-induced Obesity and Fatty Liver by Suppressing Sterol Regulatory Element-binding Protein (SREBP) Activation*

    Science.gov (United States)

    Miyata, Shingo; Inoue, Jun; Shimizu, Makoto; Sato, Ryuichiro

    2015-01-01

    Sterol regulatory element-binding proteins (SREBPs) are key transcription factors that stimulate the expression of genes involved in fatty acid and cholesterol biosynthesis. Here, we demonstrate that a prenylated flavonoid in hops, xanthohumol (XN), is a novel SREBP inactivator that reduces the de novo synthesis of fatty acid and cholesterol. XN independently suppressed the maturation of SREBPs of insulin-induced genes in a manner different from sterols. Our results suggest that XN impairs the endoplasmic reticulum-to-Golgi translocation of the SREBP cleavage-activating protein (SCAP)-SREBP complex by binding to Sec23/24 and blocking SCAP/SREBP incorporation into common coated protein II vesicles. Furthermore, in diet-induced obese mice, dietary XN suppressed SREBP-1 target gene expression in the liver accompanied by a reduction of the mature form of hepatic SREBP-1, and it inhibited the development of obesity and hepatic steatosis. Altogether, our data suggest that XN attenuates the function of SREBP-1 by repressing its maturation and that it has the potential of becoming a nutraceutical food or pharmacological agent for improving metabolic syndrome. PMID:26140926

  19. TM6SF2 and MAC30, new enzyme homologues in sterol metabolism and common metabolic disease.

    Directory of Open Access Journals (Sweden)

    Luis eSanchez-Pulido

    2014-12-01

    Full Text Available Carriers of the Glu167Lys coding variant in the TM6SF2 gene have recently been identified as being more susceptible to non-alcoholic fatty liver disease (NAFLD, yet exhibit lower levels of circulating lipids and hence are protected against cardiovascular disease. Despite the physiological importance of these observations, the molecular function of TM6SF2 remains unknown, and no sequence similarity with functionally characterised proteins has been identified. In order to trace its evolutionary history and to identify functional domains, we embarked on a computational protein sequence analysis of TM6SF2. We identified a new domain, the EXPERA domain, which is conserved among TM6SF, MAC30/TMEM97 and EBP (D8,D7 sterol isomerase protein families. EBP mutations are the cause of chondrodysplasia punctata 2 X-linked dominant (CDPX2, also known as Conradi-Hünermann-Happle syndrome, a defective cholesterol biosynthesis disorder. Our analysis of evolutionary conservation among EXPERA domain-containing families and the previously suggested catalytic mechanism for the EBP enzyme, indicate that TM6SF and MAC30/TMEM97 families are both highly likely to possess, as for the EBP family, catalytic activity as sterol isomerases. This unexpected prediction of enzymatic functions for TM6SF and MAC30/TMEM97 is important because it now permits detailed experiments to investigate the function of these key proteins in various human pathologies, from cardiovascular disease to cancer.

  20. Activity of cycloartane-type triterpenes and sterols isolated from Musa paradisiaca fruit peel against Leishmania infantum chagasi.

    Science.gov (United States)

    Silva, A A S; Morais, S M; Falcão, M J C; Vieira, I G P; Ribeiro, L M; Viana, S M; Teixeira, M J; Barreto, F S; Carvalho, C A; Cardoso, R P A; Andrade-Junior, H F

    2014-09-25

    The aim of the study was to evaluate in vitro the antileishmanial activity of triterpenes and sterols isolated from Musa paradisiaca (banana) fruit peel used traditionally to treat leishmaniasis. The compounds were isolated from the ethanolic extract of the peel of the banana fruit by column chromatography. The chemical structure of compounds was determined by (1)H and (13)C - nuclear magnetic resonance spectroscopy. The cytotoxicity was measured in RAW 264.7 cells and LLC-MK2. Leishmanicidal activity against L. infantum chagasi promastigotes was performed by the MTT colorimetric method and activity against amastigotes was assayed in mammalian cells using in situ ELISA method. Five compounds were identified, consisting of three triterpenes: cycloeucalenone, 31-norcyclolaudenone and 24-methylene-cicloartanol and a mixture of two sterols: beta-sitosterol and stigmasterol. With the exception of cycloeucalenone, all compounds showed statistically similar activity against promastigote to pentamidine. While, acting against amastigotes, excluding 31-norcyclolaudenone, other compounds showed activity similar to amphotericin B. All compounds showed low cytotoxicity in mammalian cells. This study partially confirms the use of Musa paradisiaca in folk medicine against leishmaniasis. Further in vivo studies are necessary to evaluate the efficacy. Copyright © 2014 Elsevier GmbH. All rights reserved.

  1. Leishmania infantum sterol 24-c-methyltransferase formulated with MPL-SE induces cross-protection against L. major infection.

    Science.gov (United States)

    Goto, Yasuyuki; Bhatia, Ajay; Raman, Vanitha S; Vidal, Silvia E Z; Bertholet, Sylvie; Coler, Rhea N; Howard, Randall F; Reed, Steven G

    2009-05-11

    The enzyme sterol 24-c-methyltranferase (SMT) is required for the biosynthesis of ergosterol, the major membrane sterol in Leishmania parasites. SMT and ergosterol are not found in mammals, so this protein may be an attractive target for anti-leishmanial vaccines and drugs. We have previously demonstrated that SMT from L. infantum, which causes visceral leishmaniasis, is a protective antigen against this parasite. Because this protein is highly conserved among Leishmania species, we evaluated the potential of SMT to cross-protect against a different form of leishmaniasis. Here, we show that immunization with L. infantum SMT, formulated with monophosphoryl lipid A in stable emulsion (MPL-SE), protects mice from cutaneous leishmaniasis caused by L. major. In BALB/c mice the vaccine preparation induced antigen-specific multi-functional CD4(+) T cells capable of producing IFN-gamma, IL-2, and/or TNF-alpha upon antigen re-exposure, and MPL-SE was indispensable to direct immune responses to SMT towards Th1. Mice immunized with the SMT/MPL-SE vaccine developed significantly smaller lesions following ear challenge with L. major. These results suggest that SMT is a promising vaccine antigen for multiple forms of leishmaniasis.

  2. Optimization and modeling for the synthesis of sterol esters from deodorizer distillate by lipase-catalyzed esterification.

    Science.gov (United States)

    Zhang, Xinyu; Yu, Jiang; Zeng, Aiwu

    2017-03-01

    In this paper, cotton seed oil deodorizer distillate (CSODD), was recovered to obtain fatty acid sterol ester (FASE), which is one of the biological activated substances added as human therapeutic to lower cholesterol. Esterification reactions were carried out using Candida rugosa lipase as a catalyst, and the conversion of phytosterol was optimized using response surface methodology. The highest conversion (90.8 ± 0.4%) was reached at 0.84 wt% enzyme load, 1:25 solvent/CSODD mass ratio, and 44.2 °C after 12 H reaction. A kinetic model based on the reaction rate equation was developed to describe the reaction process. The activation energy of the reaction was calculated to be 56.9 kJ/mol and the derived kinetic parameters provided indispensable basics for further study. The optimization and kinetic research of synthesizing FASE from deodorizer distillate provided necessary information for the industrial applications in the near future. Experimental results showed that the proposed process is a promising alternative to recycle sterol esters from vegetable oil deodorizer distillates in a mild, efficient, and environmental friendly method. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

  3. Sterol intermediates of cholesterol biosynthesis inhibit hair growth and trigger an innate immune response in cicatricial alopecia.

    Directory of Open Access Journals (Sweden)

    Sreejith P Panicker

    Full Text Available Primary cicatricial alopecia (PCA is a group of inflammatory hair disorders that cause scarring and permanent hair loss. Previous studies have implicated PPARγ, a transcription factor that integrates lipogenic and inflammatory signals, in the pathogenesis of PCA. However, it is unknown what triggers the inflammatory response in these disorders, whether the inflammation is a primary or secondary event in disease pathogenesis, and whether the inflammatory reaction reflects an autoimmune process. In this paper, we show that the cholesterol biosynthetic pathway is impaired in the skin and hair follicles of PCA patients. Treatment of hair follicle cells with BM15766, a cholesterol biosynthesis inhibitor, or 7-dehydrocholesterol (7-DHC, a sterol precursor, stimulates the expression of pro-inflammatory chemokine genes. Painting of mouse skin with 7-DHC or BM15766 inhibits hair growth, causes follicular plugging and induces the infiltration of inflammatory cells into the interfollicular dermis. Our results demonstrate that cholesterologenic changes within hair follicle cells trigger an innate immune response that is associated with the induction of toll-like receptor (TLR and interferon (IFN gene expression, and the recruitment of macrophages that surround the hair follicles and initiate their destruction. These findings reveal a previously unsuspected role for cholesterol precursors in PCA pathogenesis and identify a novel link between sterols and inflammation that may prove transformative in the diagnosis and treatment of these disorders.

  4. Heterologous expression of a fungal sterol esterase/lipase in different hosts: Effect on solubility, glycosylation and production.

    Science.gov (United States)

    Vaquero, María Eugenia; Barriuso, Jorge; Medrano, Francisco Javier; Prieto, Alicia; Martínez, María Jesús

    2015-12-01

    Ophiostoma piceae secretes a versatile sterol-esterase (OPE) that shows high efficiency in both hydrolysis and synthesis of triglycerides and sterol esters. This enzyme produces aggregates in aqueous solutions, but the recombinant protein, expressed in Komagataella (synonym Pichia) pastoris, showed higher catalytic efficiency because of its higher solubility. This fact owes to a modification in the N-terminal sequence of the protein expressed in Pichia pastoris, which incorporated 4-8 additional amino acids, affecting its aggregation behavior. In this study we present a newly engineered P. pastoris strain with improved protein production. We also produced the recombinant protein in the yeast Saccharomyces cerevisiae and in the prokaryotic host Escherichia coli, corroborating that the presence of these N-terminal extra amino acids affected the protein's solubility. The OPE produced in the new P. pastoris strain presented the same physicochemical properties than the old one. An inactive form of the enzyme was produced by the bacterium, but the recombinant esterase from both yeasts was active even after its enzymatic deglycosylation, suggesting that the presence of N-linked carbohydrates in the mature protein is not essential for enzyme activity. Although the yield in S. cerevisiae was lower than that obtained in P. pastoris, this work demonstrates the importance of the choice of the heterologous host for successful production of soluble and active recombinant protein. In addition, S. cerevisiae constitutes a good engineering platform for improving the properties of this biocatalyst.

  5. Curcumin up-regulates LDL receptor expression via the sterol regulatory element pathway in HepG2 cells.

    Science.gov (United States)

    Dou, Xiaobing; Fan, Chunlei; Wo, Like; Yan, Jin; Qian, Ying; Wo, Xingde

    2008-09-01

    Plasma low-density lipoprotein-cholesterol (LDL-C) is mainly taken up and cleared by the hepatocellular LDL receptor (LDL-R). LDL-R gene expression is regulated by the sterol regulatory element binding proteins (SREBPs). Previous studies have shown that curcumin reduces plasma LDL-C and has hypolipidemic and anti-atherosclerotic effects. Herein, we investigated the effect of curcumin on LDL-R expression and its molecular mechanism in HepG2 cells. Curcumin increased LDL-R expression (mRNA and protein) and the resultant uptake of DiI-LDL in a dose- and time-dependent manner. Using a GFP reporter system in a transfected HepG2/SRE-GFP cell line, we found that curcumin activated the sterol regulatory element of the LDL-R promoter. In HepG2/Insig2 cells, curcumin reversed the inhibition of LDL-R expression induced by Insig2 overexpression. These data demonstrate that curcumin increases LDL-R protein expression and uptake activity via the SREBPs pathway. These findings contribute to our further understanding of the cholesterol-lowering and anti-atherosclerotic effects of curcumin.

  6. Analysis of monoglycerides, diglycerides, sterols, and free fatty acids in coconut (Cocos nucifera L.) oil by 31P NMR spectroscopy.

    Science.gov (United States)

    Dayrit, Fabian M; Buenafe, Olivia Erin M; Chainani, Edward T; de Vera, Ian Mitchelle S

    2008-07-23

    Phosphorus-31 nuclear magnetic resonance spectroscopy ( (31)P NMR) was used to differentiate virgin coconut oil (VCO) from refined, bleached, deodorized coconut oil (RCO). Monoglycerides (MGs), diglycerides (DGs), sterols, and free fatty acids (FFAs) in VCO and RCO were converted into dioxaphospholane derivatives and analyzed by (31)P NMR. On the average, 1-MG was found to be higher in VCO (0.027%) than RCO (0.019%). 2-MG was not detected in any of the samples down to a detection limit of 0.014%. On the average, total DGs were lower in VCO (1.55%) than RCO (4.10%). When plotted in terms of the ratio [1,2-DG/total DGs] versus total DGs, VCO and RCO samples grouped separately. Total sterols were higher in VCO (0.096%) compared with RCO (0.032%), and the FFA content was 8 times higher in VCO than RCO (0.127% vs 0.015%). FFA determination by (31)P NMR and titration gave comparable results. Principal components analysis shows that the 1,2-DG, 1,3-DG, and FFAs are the most important parameters for differentiating VCO from RCO.

  7. Analysis of sterol and other components present in unsaponifiable matters of mahua, sal and mango kernel oil.

    Science.gov (United States)

    Dhara, Rupali; Bhattacharyya, Dipak K; Ghosh, Mahua

    2010-01-01

    The amount and characterization of phytosterol and other minor components present in three Indian minor seed oils, mahua (Madhuca latifolia), sal (Shorea robusta) and mango kernel (Mangifera indica), have been done. Theses oils have shown commercial importance as cocoa-butter substitutes because of their high symmetrical triglycerides content. The conventional thin layer chromatography (TLC), gas chromatography (GC) & gas chromatography-mass spectroscopy (GC-MS) techniques were used to characterize the components and the high performance thin layer chromatography (HPTLC) technique was used to quantify the each group of components. The experimental data showed that the all the three oils are rich in sterol content and among all the sterols, beta-sitosterol occupies the highest amount. Sal oil contains appreciable amount of cardenolides, gitoxigenin. Tocopherol is present only in mahua oil and oleyl alcohol is present in mango kernel oil. Hydrocarbon, squalene, is present in all the three oils. The characterization of these minor components will help to detect the presence of the particular oil in specific formulations and to assess its stability as well as nutritional quality of the specific oil.

  8. Silencing of sterol glycosyltransferases modulates the withanolide biosynthesis and leads to compromised basal immunity of Withania somnifera

    Science.gov (United States)

    Singh, Gaurav; Tiwari, Manish; Singh, Surendra Pratap; Singh, Surendra; Trivedi, Prabodh Kumar; Misra, Pratibha

    2016-01-01

    Sterol glycosyltransferases (SGTs) catalyse transfer of glycon moiety to sterols and their related compounds to produce diverse glyco-conjugates or steryl glycosides with different biological and pharmacological activities. Functional studies of SGTs from Withania somnifera indicated their role in abiotic stresses but details about role under biotic stress are still unknown. Here, we have elucidated the function of SGTs by silencing SGTL1, SGTL2 and SGTL4 in Withania somnifera. Down-regulation of SGTs by artificial miRNAs led to the enhanced accumulation of withanolide A, withaferin A, sitosterol, stigmasterol and decreased content of withanoside V in Virus Induced Gene Silencing (VIGS) lines. This was further correlated with increased expression of WsHMGR, WsDXR, WsFPPS, WsCYP710A1, WsSTE1 and WsDWF5 genes, involved in withanolide biosynthesis. These variations of withanolide concentrations in silenced lines resulted in pathogen susceptibility as compared to control plants. The infection of Alternaria alternata causes increased salicylic acid, callose deposition, superoxide dismutase and H2O2 in aMIR-VIGS lines. The expression of biotic stress related genes, namely, WsPR1, WsDFS, WsSPI and WsPR10 were also enhanced in aMIR-VIGS lines in time dependent manner. Taken together, our observations revealed that a positive feedback regulation of withanolide biosynthesis occurred by silencing of SGTLs which resulted in reduced biotic tolerance. PMID:27146059

  9. Fluorescence Experiments with Quinine

    Science.gov (United States)

    O'Reilly, James E.

    1975-01-01

    Describes a series of experiments which illustrate the analytical capabilities of fluorescence, and outlines two straightforward analyses involving real analyses. These experiments are suitable for an undergraduate instrumental analysis course and require approximately six to seven hours of laboratory time. (MLH)

  10. FLEX: fluorescence explorer

    NARCIS (Netherlands)

    Stoll, M.Ph.; Court, A.J.; Smorenburg, C.; Visser, H.; Crocco, L.; Heilimo, J.; Honig, A.

    1999-01-01

    FLEX is a scientifically driven space mission to provide demonstration/validation of the instrumentation and technique for measuring the natural fluorescence of vegetation in the Fraunhofer lines. The payload consists of high spectral resolution (0.1-0.3 nm) CCD imaging grating spectrometer with two

  11. Structural complex of sterol 14[alpha]-demethylase (CYP51) with 14[alpha]-methylenecyclopropyl-[delta]7-24, 25-dihydrolanosterol[S

    Energy Technology Data Exchange (ETDEWEB)

    Hargrove, Tatiana Y.; Wawrzak, Zdzislaw; Liu, Jialin; Waterman, Michael R.; Nes, W. David; Lepesheva, Galina I. (Vanderbilt); (TTU); (NWU)

    2012-06-28

    Sterol 14{alpha}-demethylase (CYP51) that catalyzes the removal of the 14{alpha}-methyl group from the sterol nucleus is an essential enzyme in sterol biosynthesis, a primary target for clinical and agricultural antifungal azoles and an emerging target for antitrypanosomal chemotherapy. Here, we present the crystal structure of Trypanosoma (T) brucei CYP51 in complex with the substrate analog 14{alpha}-methylenecyclopropyl-{Delta}7-24,25-dihydrolanosterol (MCP). This sterol binds tightly to all protozoan CYP51s and acts as a competitive inhibitor of F105-containing (plant-like) T. brucei and Leishmania (L) infantum orthologs, but it has a much stronger, mechanism-based inhibitory effect on I105-containing (animal/fungi-like) T. cruzi CYP51. Depicting substrate orientation in the conserved CYP51 binding cavity, the complex specifies the roles of the contact amino acid residues and sheds new light on CYP51 substrate specificity. It also provides an explanation for the effect of MCP on T. cruzi CYP51. Comparison with the ligand-free and azole-bound structures supports the notion of structural rigidity as the characteristic feature of the CYP51 substrate binding cavity, confirming the enzyme as an excellent candidate for structure-directed design of new drugs, including mechanism-based substrate analog inhibitors.

  12. Feeding conditions control the expression of genes involved in sterol metabolism in peripheral blood mononuclear cells of normoweight and diet-induced (cafeteria) obese rats

    NARCIS (Netherlands)

    Caimari, A.; Oliver, P.; Rodenburg, W.; Keijer, J.; Palou, A.

    2010-01-01

    Peripheral blood mononuclear cells (PBMC) are easily obtainable cells from blood whose gene expression profiles have been proven to be highly robust in distinguishing a disease state from healthy state. Sterol metabolism is of physiological importance, and although its nutritional response in liver

  13. Trichodiene production in a Trichoderma harzianum erg1-silenced strain provides evidence of the importance of the sterol biosynthetic pathway in inducing plant defense-related gene expression

    Science.gov (United States)

    Trichoderma species are often used as biocontrol agents against plant-pathogenic fungi. A complex molecular interaction occurs among the biocontrol agent, the antagonistic fungus, and the plant. Terpenes and sterols produced by the biocontrol fungus have been found to affect gene expression in both ...

  14. Feeding conditions control the expression of genes involved in sterol metabolism in peripheral blood mononuclear cells of normoweight and diet-induced (cafeteria) obese rats

    NARCIS (Netherlands)

    Caimari, A.; Oliver, P.; Rodenburg, W.; Keijer, J.; Palou, A.

    2010-01-01

    Peripheral blood mononuclear cells (PBMC) are easily obtainable cells from blood whose gene expression profiles have been proven to be highly robust in distinguishing a disease state from healthy state. Sterol metabolism is of physiological importance, and although its nutritional response in liver

  15. Spreads enriched with three different levels of vegetable oil sterols and the degree of cholesterol lowering in normocholesterolaemic and mildly hypercholesterolaemic subjects

    NARCIS (Netherlands)

    Hendriks, H.F.J.; Weststrate, J.A.; Vliet, T. van; Meijer, G.W.

    1999-01-01

    Objective: To investigate the dose-response relationship between cholesterol lowering and three different, relatively low intake levels of plant sterols (0.83, 1.61, 3.24 g/d) from spreads. To investigate the effects on lipid-soluble (pro)vitamins. Design: A randomized double-blind placebo

  16. Potential of gas chromatography-atmospheric pressure chemical ionization-time-of-flight mass spectrometry for the determination of sterols in human plasma.

    Science.gov (United States)

    Matysik, S; Schmitz, G; Bauer, S; Kiermaier, J; Matysik, F-M

    2014-04-11

    The application of Gas Chromatography (GC)-Atmospheric Pressure Chemical Ionization (APCI)-Time-of-Flight Mass Spectrometry (TOF-MS) is presented for sterol analysis in human plasma. A commercial APCI interface was modified to ensure a well-defined humidity which is essential for controlled ionization. In the first step, optimization regarding flow rates of auxiliary gases was performed by using a mixture of model analytes. Secondly, the qualitative and quantitative analysis of sterols including oxysterols, cholesterol precursors, and plant sterols as trimethylsilyl-derivatives was successfully carried out. The characteristics of APCI together with the very good mass accuracy of TOF-MS data enable the reliable identification of relevant sterols in complex matrices. Linear calibration lines and plausible results for healthy volunteers and patients could be obtained whereas all mass signals were extracted with an extraction width of 20 ppm from the full mass data set. One advantage of high mass accuracy can be seen in the fact that from one recorded run any search for m/z can be performed. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Co-opted oxysterol-binding ORP and VAP proteins channel sterols to RNA virus replication sites via membrane contact sites.

    Science.gov (United States)

    Barajas, Daniel; Xu, Kai; de Castro Martín, Isabel Fernández; Sasvari, Zsuzsanna; Brandizzi, Federica; Risco, Cristina; Nagy, Peter D

    2014-10-01

    Viruses recruit cellular membranes and subvert cellular proteins involved in lipid biosynthesis to build viral replicase complexes and replication organelles. Among the lipids, sterols are important components of membranes, affecting the shape and curvature of membranes. In this paper, the tombusvirus replication protein is shown to co-opt cellular Oxysterol-binding protein related proteins (ORPs), whose deletion in yeast model host leads to decreased tombusvirus replication. In addition, tombusviruses also subvert Scs2p VAP protein to facilitate the formation of membrane contact sites (MCSs), where membranes are juxtaposed, likely channeling lipids to the replication sites. In all, these events result in redistribution and enrichment of sterols at the sites of viral replication in yeast and plant cells. Using in vitro viral replication assay with artificial vesicles, we show stimulation of tombusvirus replication by sterols. Thus, co-opting cellular ORP and VAP proteins to form MCSs serves the virus need to generate abundant sterol-rich membrane surfaces for tombusvirus replication.

  18. 植物甾醇的应用及检测方法研究进展%Advancements of Study on Application and Detection of Plant Sterol

    Institute of Scientific and Technical Information of China (English)

    石馨; 魏雪冬; 刘波; 赵晶

    2014-01-01

    植物甾醇作为一种天然活性物质,安全性极高。近年来,植物甾醇被广泛应用于食品、乳品、医药、化妆品、饲料等行业,具有广阔的研究及应用前景。本文介绍了植物甾醇的生理功能及其应用进展,并对植物甾醇的检测方法进行了简述。%As a natural active substance, plant sterol has high security. In recent years, plant sterol has been widely applied in food, dairy, medical science, cosmetics, animal food and so on. It has a broad research and application prospects. This paper reviews the advancement of study on physiological function and application of plant sterol. Accordingly, it also introduces the detection method of plant sterol.

  19. Lathosterol to cholesterol ratio in serum predicts cholesterol lowering response to plant sterol consumption in a dual center, randomized, single-blind placebo controlled trial

    Science.gov (United States)

    Benefits of plant sterols (PS) for cholesterol lowering are compromised by large variability in efficacy across individuals. High fractional cholesterol synthesis measured by deuterium incorporation has been associated with non-response to PS consumption; however, prospective studies showing this as...

  20. Purification of nonspecific lipid transfer protein (sterol carrier protein 2) from human liver and its deficiency in livers from patients with cerebro-hepato-renal (Zellweger) syndrome

    NARCIS (Netherlands)

    Amerongen, A. van; Helms, J.B.; Krift, T.P. van der; Schutgens, R.B.H.; Wirtz, K.W.A.

    1987-01-01

    The nonspecific lipid transfer protein (i.e., sterol carrier protein 2) from human liver was purified to homogeneity using ammonium sulfate precipitation, CM-cellulose chromatography, molecular sieve chromatography and fast protein liquid chromatography. Its amino acid composition was determined and